WO2015118634A1 - Lighting device, observation device, and observation method - Google Patents

Abstract

A lighting device wherein a sample is lighted by interference fringes, the device provided with: a light bundle generating unit that generates first and second light bundles from light that is emitted from a light source; a phase imparting unit that creates a phase difference between the first light bundle and the second light bundle; an interference optical system that interferes with the first light bundle and the second light bundle and generates interference fringes; and a drive control unit that drives the light bundle generating unit and the phase imparting unit and that alters the phase difference or the direction of the interference fringes or both.

Description

Illumination device, observation device, and observation method

The present invention relates to an illumination device, an observation device, and an observation method.

There is a super-resolution microscope that enables observation beyond the resolution of the optical system in a microscope apparatus. As a form of this super-resolution microscope, the specimen is illuminated with spatially modulated illumination light to obtain a modulated image, and the modulation component contained in the modulated image is removed (demodulated), thereby super-resolution of the specimen. A structured illumination microscope (SIM) that generates an image is known (see, for example, Patent Document 1). In this method, a super-resolution image is generated based on a plurality of images picked up by applying phase modulation to the illumination light beam, thereby enabling observation beyond the resolution of the optical system.

US Pat. No. 6,239,909

M.G.L.Gustafsson, D.A.Agard, J.W.Sedat ”Doubling the lateral resolution of wide-field fluorescence microscopy using structured illumination, Proceedings of the SPIE-The International Society for 919Optical Engineering.

However, there is a problem that the time for generating a super-resolution image cannot be shortened depending on the above-described microscope apparatus.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an illumination device, an observation device, and an observation method that can shorten the time for generating a super-resolution image.

[1] One embodiment of the present invention is an illumination device that illuminates a specimen with interference fringes, a light beam generation unit that generates a first light beam and a second light beam from light emitted from a light source; A phase applying unit that provides a phase difference between the first light bundle and the second light bundle; an interference optical system that generates interference fringes by causing the first light bundle and the second light bundle to interfere; and An illumination device comprising: a drive control unit that drives each of the bundle generation unit and the phase applying unit to change at least one of the direction of the interference fringes and the phase difference.

[2] Further, according to an embodiment of the present invention, an image is formed by the above-described illumination device, an imaging optical system that forms an image of a sample illuminated by the interference fringe by the illumination device, and the imaging optical system. An observation apparatus comprising: an imaging unit that captures an image of the specimen; and a calculation unit that generates an image of the specimen based on the image captured by the imaging unit.

[3] Further, according to an embodiment of the present invention, the above-described illumination device illuminates the specimen with interference fringes and is imaged by an imaging optical system that forms an image of the specimen illuminated by the illumination. An observation method comprising: capturing an image of the sample; and a calculation procedure for generating an image of the sample based on the image of the sample captured by the imaging.

According to the present invention, it is possible to shorten the time for generating the super-resolution image.

1 is a schematic diagram illustrating an observation apparatus according to a first embodiment of the present invention. It is the top view of the diffraction grating seen from the direction of the optical axis of an illumination optical system. It is a top view of the shutter member seen from the direction of the optical axis of an illumination optical system. It is a figure which shows the position on the conjugate surface of the spot light formed by converging each diffracted light diffracted by the diffraction grating on the conjugate surface. It is a figure which shows a transmissive member. It is a figure which shows the light beam from a shutter member to an illumination area | region. It is a schematic diagram which shows an example of the 1st positional relationship of a light beam production | generation part and a phase provision part. It is a schematic diagram which shows an example of the 2nd positional relationship of a light beam production | generation part and a phase provision part. It is a schematic diagram which shows an example of the 3rd positional relationship of a light beam production | generation part and a phase provision part. It is a sequence diagram which shows an example of the control sequence by a drive control part. It is a perspective view which shows the modification of a shutter member. It is a figure which shows schematic structure of the illuminating device of a modification. It is a figure which shows the observation apparatus which concerns on 2nd Embodiment. It is a figure which shows a diffraction grating. It is a figure which shows the position of the spot in the conjugate plane of each diffracted light. It is a schematic diagram which shows an example of the positional relationship of a light beam production | generation part and a phase provision part. It is a schematic diagram which shows an example of the direction of the interference fringe which a drive control part controls. It is a figure which shows the modification of an illuminating device. It is a figure which shows the modification of a light beam production | generation part. It is a figure which shows the modification of a phase provision part. It is a figure which shows the modification of an observation apparatus. It is a figure which shows the modification of an optical path rotation member. It is a figure which shows the observation apparatus which concerns on 3rd Embodiment. It is the top view which looked at the shutter member and the transmissive member from the direction of the optical axis. It is a schematic diagram which shows the 1st example of the positional relationship of a light beam production | generation part and a phase provision part. It is a schematic diagram which shows the 2nd example of the positional relationship of a light beam production | generation part and a phase provision part. It is a sequence diagram which shows an example of the control sequence by a drive control part.

[First embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing an observation apparatus according to the first embodiment of the present invention. The observation apparatus 1 of this embodiment is a microscope apparatus that observes a specimen SP such as a living body cell, for example.

The observation apparatus 1 includes an illumination device 10, an imaging optical system 200, an imaging unit 210, and a calculation unit 220. The illumination device 10 illuminates the specimen SP with interference fringes. The imaging optical system 200 forms an image of the specimen SP (interference fringe image) illuminated by the illumination device 10 with the interference fringes. The imaging unit 210 captures an image of the specimen SP imaged by the imaging optical system 200. The computing unit 220 generates an image of the specimen SP based on the image captured by the imaging unit 210.

The illumination device 10 forms interference fringes on the predetermined illumination area LA with the illumination light IL. The specimen SP is arranged on or near the illumination area LA. That is, the illuminating device 10 illuminates the specimen SP with the illumination light IL and forms interference fringes on the specimen SP.

The illumination device 10 according to the present embodiment includes a light source device 100, a light beam generation unit 110, a phase adding unit 120, an illumination optical system 150, and a drive control unit 160. The light beam generation unit 110 generates a first light beam and a second light beam from the light emitted from the light source device 100. The diffracted light LM1 shown in FIG. 1 is an example of a first light beam. The diffracted light LM2 shown in FIG. 1 is an example of a second light beam. The phase imparting unit 120 imparts a phase difference between the first light flux and the second light flux. The illumination optical system 150 generates interference fringes by causing the first light flux and the second light flux to interfere in the illumination area LA (so-called two-beam interference). The drive control unit 160 drives each of the light flux generation unit 110 and the phase imparting unit 120, and the interference fringe direction and the interference fringe phase (that is, the phase difference between the first light flux and the second light flux) and To control. The illumination optical system 150 is an example of an interference optical system. Here, the direction of the interference fringes indicates a direction in which the light intensity periodically changes in the light intensity distribution of the interference fringes formed in the illumination area LA.

The light source device 100 according to the present embodiment includes a light source 101, a light guide member 102, and a collimator 103. The light source 101 includes a light emitting element such as a laser diode. The light guide member 102 includes, for example, an optical fiber, and guides light from the light source 101 to the collimator 103. In the present embodiment, the collimator 103 that uses an emission end face from which light is emitted from the light guide member 102 as a secondary light source makes the light emitted from the secondary light source parallel light.

The light beam generation unit 110 according to the present embodiment includes a diffraction grating 111 and a shutter member 131. The diffraction grating 111 is disposed in the optical path between the light source device 100 and the illumination optical system 150. In the present embodiment, the light emitted from the light source 101 and diffracted by the diffraction grating 111 is appropriately referred to as illumination light IL. The shutter member 131 is disposed on the optical path between the diffraction grating 111 and the illumination area LA. The phase applying unit 120 according to the present embodiment includes a transmission member 141 that transmits at least part of the light from the light source 101. The transmission member 141 is disposed on the optical path between the diffraction grating 111 and the illumination area LA. The transmitting member 141 is an example of the phase applying unit 120. Details of the light flux generation unit 110 and the phase applying unit 120 will be described later.

The illumination optical system 150 according to the present embodiment is a refractive optical system including a plurality of lens members. The illumination optical system 150 includes a projection lens 151, a relay lens 152, a diaphragm member 155, a field lens 153, a dichroic mirror 156, an excitation filter 156a, a barrier filter 156b, and an objective lens 154.

In the present embodiment, at least one of the projection lens 151, the relay lens 152, the field lens 153, and the objective lens 154 includes a lens member having a rotationally symmetric shape around a predetermined symmetry axis. Examples of such a lens member include a spherical lens and an aspheric lens. In the present embodiment, the symmetry axis of the rotationally symmetric lens member included in the illumination optical system 150 is appropriately referred to as an optical axis AX1 of the illumination optical system 150.

The projection lens 151 forms an image of the light exit end face of the light guide member 102 on the conjugate plane OS1. A plane conjugate with the diffraction grating 111 is defined as a conjugate plane OS2. An intermediate image of the diffraction grating 111 is formed on the conjugate plane OS2. A plane optically conjugate with the conjugate plane OS2 is defined as a conjugate plane OS3. Since the conjugate plane OS2 is optically conjugate with the diffraction grating 111, the conjugate plane OS3 is optically conjugate with the diffraction grating 111. The illumination area LA of the illumination device 10 is set in the vicinity of the conjugate plane OS3 so that the focusing accuracy of the interference fringes formed on the conjugate plane OS3 or the specimen SP is within an allowable range.

The diaphragm member 155 is a so-called field diaphragm, and is disposed on or near the conjugate plane OS2. Since the diaphragm member 155 is disposed on the conjugate surface OS2 optically conjugate with the illumination area LA, the outer shape of the illumination area LA is similar to the outer shape of the passage area through which the illumination light IL passes in the diaphragm member 155. Thus, the diaphragm member 155 defines the shape of the illumination area LA.

The illumination optical system 150 according to the present embodiment is an epi-illumination system. The objective lens 154 serves as both a part of the illumination optical system 150 and a part of the imaging optical system 200. In the illumination optical system 150, the optical path from the field lens 153 to the illumination area LA is bent by a dichroic mirror 156. The dichroic mirror 156 is disposed in the optical path between the field lens 153 and the objective lens 154. In the dichroic mirror 156, the surface on which the light from the field lens 153 is incident is inclined with respect to the optical axis AX1 of the illumination optical system 150. The surface on which light from the field lens 153 is incident on the dichroic mirror 156 has a characteristic that at least a part of the illumination light IL from the field lens 153 is reflected. At least a part of the light that has entered the dichroic mirror 156 from the field lens 153 is reflected by the dichroic mirror 156, the traveling direction is bent, and enters the illumination area LA through the objective lens 154.

The imaging optical system 200 according to the present embodiment includes an objective lens 154 and an imaging lens 157. The objective lens 154 and the imaging lens 157 form an image of the conjugate plane OS3 or the specimen SP on the conjugate plane OS4. The conjugate plane OS4 corresponds to an image plane when the conjugate plane OS3 or the specimen SP is the object plane. An image of the specimen SP illuminated by the illumination light IL is formed on the conjugate plane OS4. In the present embodiment, one or both of the objective lens 154 and the imaging lens 157 includes a lens member having a rotationally symmetric shape around a predetermined symmetry axis, and this symmetry axis is called the optical axis AX2 of the imaging optical system 200. . The optical axis AX2 of the imaging optical system 200 is coaxial with the optical axis of the objective lens 154. For example, the optical axis AX2 is set almost perpendicular to the optical axis of the illumination optical system 150 from the projection lens 151 to the field lens 153. Is done.

In the present embodiment, the dichroic mirror 156 is disposed in the optical path between the objective lens 154 and the imaging lens 157, and has a characteristic that at least part of the light from the specimen SP illuminated by the illumination light IL passes. Have The surface of the dichroic mirror 156 on which the light from the specimen SP is incident is inclined at an angle of, for example, about 45 ° with respect to each of the optical axis AX1 of the illumination optical system 150 and the optical axis AX2 of the imaging optical system 200. Yes. The light from the specimen SP illuminated by the illumination light IL enters the conjugate plane OS4 via the objective lens 154, the dichroic mirror 156, and the imaging lens 157. In the present embodiment, the dichroic mirror 156 has spectral characteristics, such that the wavelength band including the wavelength of the illumination light IL is reflected, and the wavelength band including the wavelength of the fluorescence emitted by the fluorescent material included in the specimen SP is transmitted. have. The excitation filter 156a is a spectral characteristic filter for preventing unnecessary autofluorescence generated in the light source device 100 and the illumination optical system 150 from being guided to the specimen SP and the imaging optical system 200, and transmits the wavelength of the illumination light IL. Spectral characteristics. The barrier filter 156b is for preventing the illumination light IL from being reflected by the dichroic mirror 156 and partially irradiating the specimen SP so that it does not travel through the imaging optical system along with the fluorescence. The device has an optical capacity of 5 or more for the wavelength band of the light IL, and the wavelength band including the fluorescence wavelength of the specimen SP has a high transmittance. The above is equivalent to the functions of an excitation filter, a dichroic mirror, and a barrier filter in a general fluorescence microscope.

The imaging unit 210 according to the present embodiment includes an imaging element 211 and an imaging control unit 212. The image sensor 211 includes an image sensor such as a CCD sensor or a CMOS sensor. The image sensor 211 includes a light receiving surface on which a plurality of photodiodes are arranged, and a readout circuit that reads signals from the plurality of photodiodes. The light receiving surface of the image sensor 211 is disposed on a conjugate surface OS4 that is optically conjugate with the illumination area LA in which the specimen SP is disposed. The light receiving surface of the image sensor 211 may be displaced from the conjugate surface OS4 within the range of the focal depth in the direction of the optical axis AX2 of the imaging optical system 200. The imaging control unit 212 controls the readout circuit of the imaging element 211 to control imaging timing and the like, and A / D converts the signal from the readout circuit and transfers the signal to the arithmetic unit 220. The calculation unit 220 performs a calculation for generating an image of the specimen SP based on the signal transferred from the image sensor 211. Specifically, interference fringes of a plurality of phases (that is, a plurality of phase differences between the first and second light beams) controlled by the drive control unit 160 in each direction are sampled. The calculation unit 220 is formed on the top, and sequentially generates an image of the sample on which each interference fringe is formed. For example, the interference fringes have three directions, and three kinds of phase differences (that is, three kinds of phase differences of the second light flux with respect to the first light flux) are formed on the sample. In this case, the calculation unit 220 generates nine images. Note that the direction of the interference fringes and the type of the phase difference need not be three, and each may be three or more.

Next, the light flux generation unit 110 will be described in more detail. The light beam generation unit 110 includes a diffraction grating 111 and a shutter member 131.

The diffraction grating 111 in the present embodiment is a phase type diffraction grating in which concave and convex grooves are formed on a quartz substrate, and diffracts light incident from the light source device 100. The diffraction grating 111 according to the present embodiment has a plate shape and is disposed substantially perpendicular to the optical axis AX1 of the illumination optical system 150. The diffraction grating 111 has a fixed relative position to the illumination optical system 150 and is provided so as not to rotate. The diffraction grating 111 has a periodic structure in which irregularities are periodically arranged in a direction parallel to a plane intersecting the optical axis AX1 of the illumination optical system 150. Note that the diffraction grating 111 may be a phase-type diffraction grating in which a recess having a periodic structure is embedded with a material having a refractive index different from that of the protrusion. An amplitude type diffraction grating having a light shielding film may be used. Further, a diffraction grating such as CGH may be used, and various diffraction gratings can be applied.

FIG. 2 is a plan view of the diffraction grating 111 viewed from the direction of the optical axis AX1 of the illumination optical system 150. FIG. As shown in FIG. 2, the diffraction grating 111 according to the present embodiment is a so-called multidirectional diffraction grating, and a period in which unevenness is periodically arranged in each of the first direction D1, the second direction D2, and the third direction D3. It has a structure. The first direction D1, the second direction D2, and the third direction D3 are different directions on a plane orthogonal to the optical axis AX1 of the illumination optical system 150. The periodic structure of the diffraction grating 111 shown in FIG. 2 is a so-called triangular lattice shape, and the first direction D1, the second direction D2, and the third direction D3 are approximately in the circumferential direction around the optical axis AX1 of the illumination optical system 150. It is distributed at intervals of 120 °. The light incident on the diffraction grating 111 is diffracted by the respective periodic structures in the first direction D1, the second direction D2, and the third direction D3.

That is, the light beam generation unit 110 has a periodic structure in three or more directions different from each other, and divides an incident light beam into a plurality of light beams distributed in three or more directions (multidirectional diffraction). Grid).

Due to diffraction by the periodic structure in the first direction D1, diffracted light including + (plus) 1st order diffracted light, 0th order diffracted light, and − (minus) 1st order diffracted light is refracted by the projection lens 151 and enters the shutter member 131. In the following description, the direction in which the light incident on each point of the diffraction grating 111 is diffracted by the diffraction grating 111 is appropriately referred to as a diffraction direction.

In the following description, the + 1st order diffracted light and the −1st order diffracted light diffracted by the periodic structure in the first direction D1 in the diffraction grating 111 are appropriately referred to as the + 1st order diffracted light in the first direction D1 and the −1st order diffracted light in the first direction D1. .

The + 1st order diffracted light and the −1st order diffracted light diffracted by the periodic structure in the second direction D2 are appropriately referred to as the + 1st order diffracted light in the second direction D2 and the −1st order diffracted light in the second direction D2.

+ 1st order diffracted light and −1st order diffracted light diffracted by the periodic structure in the third direction D3 are appropriately referred to as + 1st order diffracted light in the third direction D3 and −1st order diffracted light in the third direction D3.

The + 1st order diffracted light LM1 emitted from each point on the periodic structure of the diffraction grating 111 is refracted by the projection lens 151, and is a point A1 on the conjugate plane OS1 determined by the diffraction angle from the diffraction grating 111 and the focal length of the projection lens 151. And is incident on the shutter member 131. The −1st order diffracted light LM2 emitted from each point on the periodic structure of the diffraction grating 111 is refracted by the projection lens 151, and is a point on the conjugate plane OS1 determined by the diffraction angle from the diffraction grating 111 and the focal length of the projection lens 151. The light is focused on A2 and enters the shutter member 131. The position of the point A2 is point-symmetric with the position of the point A1 with respect to the optical axis AX1 of the illumination optical system 150. Between the projection lens 151 and the conjugate plane OS1, the optical path of the + 1st order diffracted light in each diffraction direction is point-symmetric with respect to the optical path of the −1st order diffracted light in the same diffraction direction with respect to the optical axis AX1 of the illumination optical system 150.

The shutter member 131 in the present embodiment is disposed in the optical path between the projection lens 151 and the conjugate plane OS1. The shutter member 131 is plate-shaped, and the surface on which the diffracted light from the projection lens 151 is incident is substantially perpendicular to the optical axis AX1 of the illumination optical system 150. The shutter member 131 can rotate around the rotation axis AX3. In the present embodiment, the rotation axis AX3 of the shutter member 131 is coaxial with the optical axis AX1 of the illumination optical system 150. The shutter member 131 is rotatable relative to the optical path of each order of diffracted light in each diffraction direction from the diffraction grating 111.

The shutter member 131 rotates around the rotation axis AX3 by torque supplied from a driving unit such as an electric motor. This drive unit is controlled by the drive control unit 160 to rotate the shutter member 131. The drive control unit 160 can control the rotation angle of the shutter member 131 by controlling the drive unit. Here, the rotation angle is an angle when the rotated body is rotated by a certain angle around a certain rotation axis. For example, the rotation angle of the shutter member 131 being 120 ° refers to a case where the shutter member 131 is rotated by 120 ° around the rotation axis AX3. The drive control unit 160 can control the relative rotation angle between the optical path of each order of diffracted light in each diffraction direction from the diffraction grating 111 and the shutter member 131 by controlling the rotation angle of the shutter member 131. .

FIG. 3 is a plan view of the shutter member 131 viewed from the direction of the optical axis AX1 of the illumination optical system 150. FIG. As shown in FIG. 3, the shutter member 131 includes a passage portion AT through which light can pass and a light shielding portion AS that blocks light.

The light shielding part AS blocks the light from the projection lens 151 by one or both of absorption and reflection. The light shielding part AS is, for example, a light shielding film formed on a base material, and the passage part AT is, for example, a region inside an opening formed in the base material constituting the light shielding part AS. The passage portion AT may be a gap between the light shielding portions AS, or may include a member that is disposed between the light shielding portions AS and through which light passes.

In the present embodiment, the shutter member 131 has a disk shape. At least a part of the light shielding part AS is arranged at a position different from the passing part AT in the circumferential direction around the rotation axis AX3. In the present embodiment, the passage portion AT is an opening and includes a first passage portion ATa and a second passage portion ATb. Each of the first passage portion ATa and the second passage portion ATb is an opening having a triangular shape when viewed from the direction of the rotation axis AX3. As the first passing portion ATa and the second passing portion ATb are separated from the rotation axis AX3 in the radial direction from the rotation axis AX3, the dimensions in the direction orthogonal to the radial direction increase. As an example, as shown in FIG. 3, the shutter member 131 includes a first passage portion ATa having a central angle θa centered on the rotation axis AX3 and a center angle θb of 20 °, and a second passage portion. ATb. Further, in the shutter member 131, the rotation axis AX3 and the periphery thereof (for example, the region AS0 shown in FIG. 3) are not opened but are light shielding portions AS.

The first passage portion ATa is disposed at a point symmetrical with the second passage portion ATb with respect to the optical axis AX1 of the illumination optical system 150. As described above, the optical path of the + 1st order diffracted light in each diffraction direction is point-symmetric with respect to the optical path of the −1st order diffracted light in the same diffraction direction with respect to the optical axis AX1 of the illumination optical system 150. In a state where the first passage portion ATa is arranged in the optical path of the + 1st order diffracted light diffracted by the periodic structure in the first direction D1 (hereinafter, this state is referred to as the first state for convenience), the second passage portion ATb is Arranged in the optical path of the first-order diffracted light diffracted by the periodic structure in the direction D1. That is, in the first state, the + 1st order diffracted light and the −1st order diffracted light diffracted by the periodic structure in the first direction D1 pass through the shutter member 131 via the first passage portion ATa and the second passage portion ATb, respectively. . On the other hand, in the first state, the light-shielding portion AS is disposed in the optical path of ± first-order diffracted light diffracted by the periodic structure in the second direction D2 and in the optical path of ± first-order diffracted light diffracted by the periodic structure in the third direction D3. . That is, the optical path of ± first-order diffracted light diffracted by the periodic structure in the second direction D2 and the optical path of ± first-order diffracted light diffracted by the periodic structure in the third direction D3 are shielded by the shutter member 131.

The first passage portion ATa can be arranged in the optical path of the + 1st order diffracted light diffracted by the periodic structure in the second direction D2 by the rotation of the shutter member 131. In a state where the first passage portion ATa is disposed in the optical path of the + 1st order diffracted light diffracted by the periodic structure in the second direction D2 (hereinafter, this state is referred to as a second state for convenience), the second passage portion ATb is It is arranged in the optical path of −1st order diffracted light diffracted by the periodic structure in two directions D2. In the second state, the light-shielding part AS is arranged in the optical path of ± first-order diffracted light diffracted by the periodic structure in the first direction D1 and in the optical path of ± first-order diffracted light diffracted by the periodic structure in the third direction D3.

The first passage portion ATa can be arranged on the optical path of the + 1st order diffracted light diffracted by the periodic structure in the third direction D3 by the rotation of the shutter member 131. In a state where the first passage portion ATa is disposed in the optical path of the + 1st order diffracted light diffracted by the periodic structure in the third direction D3 (hereinafter, this state is referred to as a third state for convenience), the second passage portion ATb It is arranged in the optical path of −1st order diffracted light diffracted by the periodic structure in the three directions D3. In the third state, the light-shielding part AS is arranged in the optical path of ± first-order diffracted light diffracted by the periodic structure in the first direction D1 and in the optical path of ± first-order diffracted light diffracted by the periodic structure in the second direction D2.

As described above, among the plurality of diffracted lights diffracted by the diffraction grating 111, the diffracted light passing through the passing part AT and the diffracted light blocked by the light shielding part AS are selected according to the rotation angle of the shutter member 131. In other words, the shutter member 131 converts ± first-order diffracted light distributed along one diffraction direction out of the plurality of light bundles divided by the diffraction grating 111 into the first light flux and the second light flux directed toward the illumination area LA. Choose as.

That is, the light beam generation unit 110 includes two light beams distributed along one direction among a plurality of light beams distributed along each of three or more directions divided by the diffraction grating 111 (multidirectional diffraction grating). Is included as a first light flux and a second light flux. The shutter member 131 is an example of a light beam selection unit.

FIG. 4 is a diagram showing the position on the conjugate plane OS1 of the spot light formed by converging each diffracted light diffracted by the diffraction grating 111 on the conjugate plane OS1. As shown in FIG. 4, the region A1 where the spot of the + 1st order diffracted light diffracted by the periodic structure in the first direction D1 is diffracted by the periodic structure in the first direction D1 with respect to the optical axis AX1 of the illumination optical system 150. It is point-symmetric with the region A2 where the spot of the first-order diffracted light is arranged. In the region A3 where the spot of the + 1st order diffracted light diffracted by the periodic structure in the second direction D2 is arranged, the spot of the first order diffracted light diffracted by the periodic structure in the second direction D2 is arranged with respect to the optical axis AX1 of the illumination optical system 150. And point symmetry with respect to the region A4. In the region A5 where the spot of the + 1st order diffracted light diffracted by the periodic structure in the third direction D3 is arranged, the spot of the first order diffracted light diffracted by the periodic structure in the third direction D3 is arranged with respect to the optical axis AX1 of the illumination optical system 150. And point symmetry with respect to the region A6.

The region A1 to the region A6 surround the optical axis AX1 of the illumination optical system 150 and are arranged in a discrete manner. As an example, the area A1 to the area A6 are arranged 60 degrees apart in the circumferential direction around the optical axis AX1 of the illumination optical system 150. In the following description, the angle in the circumferential direction around the optical axis AX1 of the illumination optical system 150 is also referred to as a rotation angle for convenience. That is, when the position in the circumferential direction around the optical axis AX1 of the illumination optical system 150 in which the region A1 is disposed is used as a reference (that is, the rotation angle is 0 °), the region A2 is rotated at a rotation angle of 180 ° and the region A3 is rotated. The region A4 is disposed at a rotation angle of 240 °, the region A5 is disposed at a rotation angle of 120 °, and the region A6 is disposed at a rotation angle of 300 °.

Next, the phase imparting unit 120 will be described in more detail. The phase providing unit 120 includes a transmission member 141 that transmits at least part of the light from the light source 101. The transmitting member 141 is disposed at the position of the conjugate plane OS1. The transmission member 141 is a plate-like member, and the surface on which light from the light source 101 enters is substantially perpendicular to the optical axis AX1 of the illumination optical system 150. The transmission member 141 is rotatable around the rotation axis AX4. In the present embodiment, the rotation axis AX4 of the transmission member 141 is coaxial with the optical axis AX1 of the illumination optical system 150. The transmissive member 141 can rotate relative to the optical path of each order of diffracted light in each diffraction direction from the diffraction grating 111.

The transmission member 141 is rotated by torque supplied from a driving unit (not shown) such as an electric motor. This drive unit is controlled by the drive control unit 160 to rotate the transmission member 141. The drive control unit 160 can control the rotation angle of the transmission member 141 by controlling the drive unit. The drive control unit 160 can control the relative rotation angle between the optical path of each order of diffracted light from the diffraction grating 111 and the transmission member 141 by controlling the rotation angle of the transmission member 141. .

5A is a perspective view of the transmissive member 141, FIG. 5B is a plan view of the transmissive member 141 viewed from the direction of the optical axis AX1 of the illumination optical system 150, and FIG. 5C is an end view of the transmissive member 141. It is the side view seen from the direction.

As shown in FIG. 5A, the transmissive member 141 according to the present embodiment has a disk shape. The transmissive member 141 includes a first region 121 and a second region 122. The transmission member 141 in the second region 122 and the transmission member 141 in the first region 121 are materials that can transmit the diffracted light diffracted by the diffraction grating 111. The transmitting member 141 transmits the diffracted light diffracted by the diffraction grating 111 with the phase of the diffracted light passing through the first region 121 and the phase of the diffracted light passing through the second region 122 being different from each other. . That is, a phase difference is set between the diffracted light transmitted through the first region 121 and the diffracted light transmitted through the second region 122. Here, for convenience, the transmission member sets the first region 121 as a reference phase region by giving a phase difference to the diffracted light transmitted through the second region 122 with reference to the phase of the diffracted light transmitted through the first region 121. And At this time, the second region 122 converts the phase of the transmitted diffracted light into a phase different from the reference phase and passes it. In the following description, the second region 122 is also referred to as a phase modulation region 122. The phase difference imparted to the diffracted light transmitted through the first region 121 and the diffracted light transmitted through the second region 122 is, for example, 0 (that is, the same phase) and 2π / 3. In this case, the phase of the diffracted light transmitted through the second region 122 is advanced or delayed by 2π / 3 with respect to the diffracted light transmitted through the first region 121. That is, the phase difference of the −1st order diffracted light with respect to the + 1st order diffracted light is set to three types of 0, 2π / 3, and −2π / 3. Note that how to change the phase difference will be described later. Note that the phase difference to be applied is not limited to 2π / 3 but may be other values.

In this embodiment, the transmission member 141 is a phase plate in which a magnesium fluoride film is formed on a quartz substrate. In this phase plate, the first region 121 is a quartz substrate, and the second region 122 is a quartz substrate and a magnesium fluoride film formed on the quartz substrate. The optical distance in the thickness direction of the transmission member 141 in the second region 122 is longer than the optical distance in the thickness direction of the transmission member 141 in the first region 121 and is different. The transmitting member 141 is not limited to a phase plate in which a magnesium fluoride film is formed on a quartz substrate, but may be a phase plate in which a silicon dioxide film is formed on a quartz substrate. It may be polished to form regions of different thickness on a quartz substrate.

As shown in FIG. 5 (b), the transmissive member 141 has a circular shape when viewed from the direction of the optical axis AX1 of the illumination optical system 150, and a rotation axis AX4 is set at the center thereof. In the circumferential direction around the rotation axis AX4, the second region 122 and the first region 121 are different regions of the transmission member 141.

Referring to the optical axis AX <b> 1 of the illumination optical system 150, at least a part of the region that is point-symmetric with the second region 122 is the first region 121. The second region 122 is distributed in a range of less than 180 ° in the circumferential direction around the rotation axis AX4. The first region 121 is distributed in a range exceeding 180 ° in the circumferential direction around the rotation axis AX4. As an example, the second region 122 is distributed in a range of 40 ° in the circumferential direction around the rotation axis AX4.

As shown in FIG. 5C, in the transmissive member 141 according to this embodiment, the thickness in the second region 122 is substantially the same as the thickness in the first region 121. In the transmissive member 141, the optical distance in the second region 122 is different from the optical distance in the first region 121 because the refractive index of the second region 122 is different from the refractive index of the first region 121. In the present embodiment, the refractive index of the second region 122 is larger than the refractive index of the first region 121, and the optical distance in the second region 122 is longer than the optical distance in the first region 121. As a result, the transmissive member 141 adjusts the phase difference between the light beam transmitted through the second region 122 and the light beam transmitted through the first region 121 so that the phase of the light beam passing through the second region 122 is delayed.

FIG. 6 is a view showing light fluxes from the shutter member 131 to the illumination area LA when the rotation angles of the shutter member 131 and the transmission member 141 are predetermined rotation angles. In FIG. 6, a part of light rays Ca of the + 1st order diffracted light passes through the first passage portion ATa of the shutter member 131 and enters the second region 122 of the transmission member 141. The light beam Ca passes through the second region 122 of the transmissive member 141, is reflected by the dichroic mirror 156, and enters the objective lens 154. The light beam Ca is refracted by the objective lens 154 and is incident on the specimen SP disposed in the illumination area LA. The partial light ray Cb of the −1st order diffracted light passes through the second passage portion ATb of the shutter member 131 and enters the first region 121 of the transmission member 141. The light ray Cb passes through the first region 121 of the transmissive member 141, is reflected by the dichroic mirror 156, and enters the objective lens 154. The light beam Cb is refracted by the objective lens 154 and enters the sample SP so as to intersect the light beam Ca of the + 1st order diffracted light on the sample SP arranged in the illumination area LA.

Thus, the + 1st order diffracted light and the −1st order diffracted light that have passed through the passage portion AT of the shutter member 131 interfere on the sample SP (so-called two-beam interference), and interference fringes are formed on the sample SP. The intensity distribution on the conjugate plane OS3 (illumination area LA) of the interference fringes between the + 1st order diffracted light and the −1st order diffracted light has an intensity corresponding to the phase difference between the + 1st order diffracted light and the −1st order diffracted light in the illumination area LA. In other words, the intensity distribution in the conjugate plane OS3 (illumination area LA) of the interference fringes can be controlled by controlling the phase difference between the + 1st order diffracted light and the −1st order diffracted light in the illumination area LA.

By the way, in this embodiment, the illuminating device 10 forms interference fringes by two-beam interference between the + 1st order diffracted light and the −1st order diffracted light. Therefore, the illumination device 10 blocks the 0th-order diffracted light transmitted without being diffracted by the diffraction grating 111 at any position between the diffraction grating 111 and the illumination area LA.

As shown in FIG. 1, the 0th-order diffracted light A3 from each point on the periodic structure of the diffraction grating 111 is refracted by the projection lens 151 and reaches the intersection A0 between the optical axis AX1 of the illumination optical system 150 and the conjugate plane OS1. Condensate. The distance between the spot light collected by the ± 1st order diffracted light diffracted by the diffraction grating 111 and the spot light collected by the 0th order diffracted light is the position of the conjugate plane OS1 in the optical path between the projection lens 151 and the relay lens 152. It becomes maximum at. Therefore, the illumination device 10 according to the present embodiment blocks the 0th-order diffracted light by the light blocking member disposed at or near the conjugate plane OS1. Specifically, the illumination device 10 according to the present embodiment blocks the 0th-order diffracted light by the shutter member 131. As described above, in the shutter member 131, the rotation axis AX3 and the surrounding area AS0 are the light shielding portion AS. This area AS0 is arranged in the vicinity of the intersection A0 regardless of the rotation angle of the shutter member 131. Further, the 0th-order diffracted light is collected at the intersection A0 between the optical axis AX1 of the illumination optical system 150 and the conjugate plane OS1 regardless of the rotation angle of the diffraction grating 111.
That is, regardless of the rotation angle of the shutter member 131 and the rotation angle of the diffraction grating 111, the optical path of the 0th-order diffracted light is shielded by the shutter member 131.

Such a light blocking member that blocks the 0th-order diffracted light is arranged at any position in the optical path between the diffraction grating 111 and the illumination area LA so that the optical path of the 0th-order diffracted light does not overlap with the optical path of ± 1st-order diffracted light. May be. The number of such light shielding members may be one or plural. Further, such a light shielding member may be provided on one or more members disposed between the diffraction grating 111 and the illumination area LA. For example, one or both of the shutter member 131 and the transmission member 141 may be provided. It may be provided.

[Operation of drive control unit]
Next, the operation of the drive control unit 160 will be described. The drive control unit 160 drives the light beam generation unit 110 and the phase applying unit 120, respectively, to control the direction and phase of the interference fringes. Specific examples of the direction and phase of the interference fringes controlled by the drive control unit 160 will be described with reference to FIGS. In the present embodiment, the direction of the interference fringes by ± 1st order diffracted light is changed in three directions, and the three kinds of phase differences of ± 1st order diffracted light (that is, −1st order diffracted light with respect to + 1st order diffracted light) The phase difference is changed to three types) and nine times of imaging are executed.

FIG. 7 is a schematic diagram illustrating an example of a first positional relationship between the light beam generation unit 110 and the phase providing unit 120 of the present embodiment. As described above, the light beam generation unit 110 includes the diffraction grating 111 and the shutter member 131. Moreover, the phase provision part 120 is provided with the permeation | transmission member 141 provided with the 1st area | region 121 and the 2nd area | region 122 as mentioned above. The drive control unit 160 controls the direction and phase of the interference fringes by driving the transmission member 141 of the phase applying unit 120 and the shutter member 131 of the light beam generation unit 110 in conjunction with each other.

Here, a specific example of a mechanism in which the drive control unit 160 controls the phase of the interference fringe out of the direction and phase of the interference fringe will be described first. Next, a specific example of a mechanism in which the drive control unit 160 controls the interference fringe direction out of the interference fringe direction and phase will be described. Next, a specific example of a mechanism in which the drive control unit 160 controls the interference fringe direction and phase in synchronization will be described.

[Control of interference fringe phase]
First, a specific example of a mechanism in which the drive control unit 160 controls the phase of the interference fringes will be described with reference to FIG. As described above, from the diffraction grating 111, the + 1st order diffracted light diffracted by the periodic structure in the first direction D1, the −1st order diffracted light diffracted by the periodic structure in the first direction D1, and the periodic structure in the second direction D2. Diffracted + 1st order diffracted light, −1st order diffracted light diffracted by the periodic structure in the second direction D2, + 1st order diffracted light diffracted by the periodic structure in the third direction D3, and −1 diffracted by the periodic structure in the third direction D3 Next-order diffracted light is emitted.

In the following description, + 1st order diffracted light diffracted by the periodic structure in the first direction D1 and −1st order diffracted light diffracted by the periodic structure in the first direction D1 are collectively referred to as diffracted light L1. The + 1st order diffracted light diffracted by the periodic structure in the second direction D2 and the −1st order diffracted light diffracted by the periodic structure in the second direction D2 are collectively referred to as diffracted light L2, and the periodic structure in the third direction D3. The + 1st order diffracted light diffracted by the above and the −1st order diffracted light diffracted by the periodic structure in the third direction D3 are collectively referred to as diffracted light L3. That is, the diffraction grating 111 emits three sets of diffracted light, that is, diffracted light L1, diffracted light L2, and diffracted light L3.

In the following description, in the case of distinguishing the + 1st order diffracted light and the −1st order diffracted light from the diffracted light L1, the + 1st order diffracted light diffracted by the periodic structure in the first direction D1 is diffracted light. A −1st order diffracted light diffracted by the periodic structure in the first direction D1 is denoted as L1-1, and is denoted as diffracted light L1-2. Similarly, the + 1st order diffracted light diffracted by the periodic structure in the second direction D2 is described as diffracted light L2-1, the −1st order diffracted light diffracted by the periodic structure in the second direction D2 is described as diffracted light L2-2, and the third direction The + 1st order diffracted light diffracted by the periodic structure of D3 is referred to as diffracted light L3-1, and the −1st order diffracted light diffracted by the periodic structure of the third direction D3 is referred to as diffracted light L3-2.
In the following description, the position shown in FIG. 7 on the shutter member 131 is set as a reference point P, and the rotation angle of the reference point P around the rotation axis AX3 (or the optical axis AX1 coaxial with the rotation axis AX3) is The rotation angle of the shutter member 131 will be described. In the following description, the position shown in FIG. 7 on the transmissive member 141 is set as a reference point Q, and the rotation angle of the reference point Q around the rotation axis AX4 (or the optical axis AX1 coaxial with the rotation axis AX4) is The rotation angle of the transmissive member 141 will be described.

Here, the diffracted light L1-1 is an example of the first light beam, and the diffracted light L1-2 is an example of the second light beam. That is, the diffraction grating 111 as the light beam generation unit 110 generates a first light beam and a second light beam from the light emitted from the light source 101.

The drive control unit 160 rotationally drives the shutter member 131 so that the passage portion AT of the shutter member 131 is disposed at the position shown in FIG. 7A (positions where the rotation angle is 0 ° and the rotation angle is 180 °). Accordingly, when the reference of the rotation angle (that is, the rotation angle of 0 °) is set as shown in FIG. 4 described above, the diffraction incident on the position of the rotation angle of 0 ° among the six diffracted lights emitted from the diffraction grating 111. The light L1-1 passes through the first passage portion ATa, and the diffracted light L1-2 incident on the rotation angle of 180 ° passes through the second passage portion ATb. Of the six diffracted lights emitted from the diffraction grating 111, the remaining four diffracted lights, that is, the diffracted light L2-1 incident on the rotation angle of 60 ° and the diffracted light L2 incident on the rotation angle of 240 °. -2, the diffracted light L3-1 incident on the rotation angle 120 ° and the diffracted light L3-2 incident on the rotation angle 300 ° are respectively shielded by the light shielding portion of the shutter member 131. Further, the 0th-order diffracted light is shielded by the shutter member 131 regardless of the rotation angle of the shutter member 131 and the rotation angle of the diffraction grating 111 as described above.

Further, the drive control unit 160 rotationally drives the transmissive member 141 so that the second region 122 of the transmissive member 141 is disposed at the position shown in FIG. 7A (position of the rotation angle 0 °). As a result, of the two diffracted lights that have passed through the passage portion AT of the shutter member 131, one of the diffracted lights L1-1 passes through the second region 122, the phase of which is modulated, and the diffracted light L1- 1 '. Of the two diffracted lights that have passed through the passage portion AT of the shutter member 131, the other diffracted light L1-2 passes through the first region 121. In this way, the phase imparting unit 120 imparts a phase difference between the diffracted light L1-1 and the diffracted light L1-2 having the same phase.

Here, as described above, the diffracted light L1-1 is an example of the first light beam, and the diffracted light L1-2 is an example of the second light beam. That is, the phase imparting unit 120 imparts a phase difference between the first light flux and the second light flux.

Here, an angle formed by two radii passing through both ends of the arc of the first passage portion ATa is defined as a central angle θa of the first passage portion ATa, and an angle formed by the two radii passing through both ends of the arc of the second passage portion ATb. The central angle θb of the second passage portion ATb is used. As described with reference to FIG. 3, the first passage portion ATa and the second passage portion ATb of the shutter member 131 each have a central angle (center angle θa and center angle θb) of 20 °. It is an opening. Here, the drive control unit 160 rotates the shutter member 131 and the transmission member 141 continuously without stopping. For this reason, when the shutter member 131 is continuously rotated, it enters the position of the rotation angle 0 ° after the reference point P reaches the rotation angle 0 ° until the reference point P reaches the rotation angle 20 °. The diffracted light L1-1 that continues to pass through the first passage portion ATa. Similarly, the diffracted light L1-2 incident on the rotation angle 180 ° from the reference point P reaching the rotation angle 0 ° to the reference point P reaching the rotation angle 20 ° Continue to pass through the passing portion ATb.
Further, the second region 122 of the transmission member 141 is distributed in a range from −20 ° to 20 ° in the circumferential direction around the rotation axis AX4 with the position of the reference point Q being 0 °. For this reason, when the transmission member 141 is continuously rotated, the reference point Q reaches the rotation angle of 0 ° until the reference point Q reaches the rotation angle of 20 ° after the reference point Q reaches the rotation angle of −20 °. The incident diffracted light L1-1 continues to pass through the second region 122. Similarly, the diffracted light L1-2 incident on the rotation angle of 180 ° from the reference point Q reaching the rotation angle −20 ° to the reference point Q reaching the rotation angle 20 ° It continues to pass through one area 121.
At this time, the drive control unit 160 continuously rotates the shutter member 131 and the transmission member 141. Specifically, the drive controller 160 rotates the reference point Q of the transmissive member 141 while rotating the reference point P of the shutter member 131 until the rotation angle reaches 20 ° from the rotation angle 0 °. Rotation is driven until the rotation angle reaches 20 °. Thus, the diffracted light L1-1 passes through the first passage portion ATa and the second region 122 after the reference point P reaches the rotation angle 0 ° and until the reference point P reaches the rotation angle 20 °. The diffracted light L1-2 continues to pass through the second passage portion ATb and the first region 121.

Next, with reference to FIG. 7B, a description will be given of a case where the drive control unit 160 changes the phase of the interference fringes without changing the direction of the interference fringes illuminated in the illumination area LA from that in FIG. To do. The drive control unit 160 starts from the state of FIG. 7A described above so that the second region 122 of the transmission member 141 is disposed at the position shown in FIG. 7B (position where the rotation angle is 120 °). 141 is continuously rotated. On the other hand, the drive control unit 160 displays the shutter member 131 so that the light flux passing through the shutter member 131 remains unchanged from the state of FIG. 7A to the diffracted light L1-1 and the diffracted light L1-2. 7 is continuously rotated from the state of (a). As a result, the two diffracted lights L1-1 and L1-2 that have passed through the passage portion AT of the shutter member 131 both pass through the first region 121. Accordingly, the phases of the diffracted light L1-1 and the diffracted light L1-2 are the same even after passing through the transmission member 141. This is different from the case shown in FIG. 7 (a), that is, the case where there is a phase difference between the diffracted light L1-1 ′ and the diffracted light L1-2 after passing through the transmitting member 141, and the presence or absence of the phase difference. To do.
Here, when the shutter member 131 is continuously rotated, it enters the position at the rotation angle of 0 ° after the reference point P reaches the rotation angle of 180 ° until the reference point P reaches the rotation angle of 200 °. The diffracted light L1-1 that continues continues to pass through the second passage portion ATb. Similarly, the diffracted light L1-2 incident on the rotation angle 180 ° from the reference point P reaching the rotation angle 180 ° until the reference point P reaches the rotation angle 200 ° is the first diffracted light L1-2. Continue to pass through the passage part ATa.
Further, when the transmission member 141 is continuously rotated, the light enters the position at the rotation angle of 0 ° after the reference point Q reaches the rotation angle of 100 ° until the reference point Q reaches the rotation angle of 140 °. Both the diffracted light L1-1 and the diffracted light L1-2 incident on the rotation angle of 180 ° continue to pass through the first region 121.
At this time, the drive control unit 160 continuously rotates the shutter member 131 and the transmission member 141 simultaneously. Specifically, the drive control unit 160 rotates the reference point Q of the transmissive member 141 while rotating the reference point P of the shutter member 131 from the rotation angle of 180 ° to the rotation angle of 200 °. Until the rotation angle reaches 140 °. Thus, the diffracted light L1-1 passes through the second passage portion ATb and the first region 121 after the reference point P reaches the rotation angle of 180 ° until the reference point P reaches the rotation angle of 200 °. The diffracted light L1-2 continues to pass through the first passage portion ATa and the first region 121.

Next, referring to FIG. 7C, the drive control unit 160 turns the transmission member 141 counterclockwise with respect to the traveling direction of the light bundle, and further rotates by 60 ° with respect to the case shown in FIG. The case where only rotational driving is performed will be described. The drive controller 160 rotationally drives the transmissive member 141 so that the second region 122 of the transmissive member 141 is disposed at the position shown in FIG. As a result, of the two diffracted lights L1-1 and L1-2 that have passed through the passage portion AT of the shutter member 131, one diffracted light L1-2 passes through the second region 122 and its phase is modulated. The phase-modulated diffracted light L1-2 ′ is obtained. Of the two diffracted lights that have passed through the passage portion AT of the shutter member 131, the other diffracted light L1-1 passes through the first region 121. In this way, the phase applying unit 120 provides a phase difference between the diffracted light L1-1 and the diffracted light L1-2 having the same phase. This is because, in the case shown in FIG. 7A, that is, the diffracted light L1-1 ′ and the diffracted light L1-2 that have passed through the transmitting member 141 have a phase difference between the two diffracted lights. It is different in that the relationship is reversed.
Here, the relationship between the shutter member 131, the diffracted light L1-1 incident on the rotation angle of 0 °, and the diffracted light L1-2 incident on the rotation angle of 180 ° is shown in FIG. Since it is the same as that described with reference to FIG.
Further, when the transmission member 141 is continuously rotated, the light enters the position at the rotation angle of 0 ° after the reference point Q reaches the rotation angle of 160 ° until the reference point Q reaches the rotation angle of 200 °. The diffracted light L1-1 continues to pass through the first region 121, and the diffracted light L1-2 incident on the rotation angle of 180 ° continues to pass through the second region 122.
At this time, the drive control unit 160 continuously rotates the shutter member 131 and the transmission member 141 simultaneously. Specifically, the drive controller 160 rotates the reference point Q of the transmission member 141 while rotating the reference point P of the shutter member 131 until the rotation angle reaches 20 ° from the rotation angle 0 °. Until the rotation angle reaches 200 °. Thus, the diffracted light L1-1 passes through the first passage portion ATa and the first region 121 after the reference point P reaches the rotation angle of 0 ° and until the reference point P reaches the rotation angle of 20 °. The diffracted light L1-2 continues to pass through the second passage portion ATb and the second region 122.

As described with reference to FIGS. 7A to 7C, the drive control unit 160 drives the light beam generation unit 110 and the phase providing unit 120 to generate the diffracted light L1-1 and the diffracted light L1-2. Changes the region of the transmissive member 141 when the light passes through the transmissive member 141. Thereby, the direction of the interference fringes generated by the diffracted light L1-1 and the diffracted light L1-2 does not change, and the phase difference between the diffracted light L1-1 and the diffracted light L1-2 changes in three ways. That is, the drive control unit 160 drives the light beam generation unit 110 and the phase providing unit 120 to change the phase difference when the direction of the interference fringes is a predetermined direction.

Up to this point, an example of a mechanism by which the drive control unit 160 controls the phase difference of the interference fringes has been described with reference to FIGS. 7 (a) to (c). Next, an example of a mechanism in which the drive control unit 160 controls the direction of interference fringes will be described with reference to FIGS. 8 and 9.

[Control of interference fringe direction]
FIG. 8 is a schematic diagram illustrating an example of a second positional relationship between the light beam generation unit 110 and the phase providing unit 120 of the present embodiment. The drive control unit 160 rotationally drives the shutter member 131 and the transmission member 141 in synchronization with each other so that the state shown in FIG. 7A is changed to the state shown in FIG. 8A. That is, the drive control unit 160 controls the direction of the interference fringes by rotationally driving the shutter member 131 and the transmission member 141 in synchronization. Specifically, the drive control unit 160 drives the shutter member 131 and the transmissive member 141 to rotate in a counterclockwise direction with respect to the traveling direction of the light bundle. At this time, the rotation angle of each diffracted light emitted from the diffraction grating 111 does not change. For this reason, when the shutter member 131 and the transmission member 141 are driven to rotate counterclockwise and the rotation angle changes from 0 ° to 60 °, the light flux passing through the shutter member 131 is changed to FIG. The diffracted light L1-1 and diffracted light L1-2 shown in FIG. 8 are switched to the diffracted light L2-1 and diffracted light L2-2 shown in FIG. Therefore, the angle of the diffracted light emitted from the transmission member 141 is displaced counterclockwise by a rotation angle of 60 °. As a result, the angle of the diffracted light incident on the objective lens 154 is displaced counterclockwise by 60 °, and the direction of the interference fringes is displaced counterclockwise by 60 °.
Also in the state shown in FIG. 8A, as in the state shown in FIG. 7A, the diffraction is performed while the shutter member 131 continuously rotates by 20 ° after the diffracted light starts to pass through the passing portion AT. The light continues to pass through the passing part AT. Specifically, the shutter member 131 is continuously rotated so that the reference point P reaches the rotation angle of 60 ° and the reference point P reaches the rotation angle of 80 °. The incident diffracted light L2-1 continues to pass through the first passage portion ATa. Similarly, the diffracted light L2-2 incident on the rotation angle 240 ° from the reference point P reaching the rotation angle 60 ° to the reference point P reaching the rotation angle 80 ° Continue to pass through the passing portion ATb.
Further, when the transmission member 141 is continuously rotated, the light enters the position at the rotation angle of 60 ° after the reference point Q reaches the rotation angle of 40 ° until the reference point Q reaches the rotation angle of 80 °. The diffracted light L2-1 continues to pass through the second region 122. Similarly, the diffracted light L2-2 incident on the rotation angle 240 ° from the reference point Q reaching the rotation angle 40 ° to the reference point Q reaching the rotation angle 80 ° is the first diffracted light L2-2. It continues to pass through the region 121.
Therefore, the diffracted light L2-1 passes through the first passage portion ATa and the second region 122 until the reference point P reaches the rotation angle 80 ° after the reference point P reaches the rotation angle 60 °. Subsequently, the diffracted light L2-2 continues to pass through the second passage portion ATb and the first region 121.

FIG. 9 is a schematic diagram illustrating an example of a third positional relationship between the light beam generation unit 110 and the phase providing unit 120 of the present embodiment. The drive control unit 160 rotationally drives the shutter member 131 and the transmission member 141 in synchronization with each other so that the state shown in FIG. 9A is changed to the state shown in FIG. At this time, the rotation angle of each diffracted light emitted from the diffraction grating 111 does not change. For this reason, when the shutter member 131 and the transmission member 141 are driven to rotate counterclockwise and the rotation angle changes from 60 ° to 120 °, the light flux passing through the shutter member 131 is changed to FIG. The diffracted light L2-1 and diffracted light L2-2 shown in FIG. 9 are switched to the diffracted light L3-1 and diffracted light L3-2 shown in FIG. Therefore, the angle of the diffracted light emitted from the transmission member 141 is further displaced counterclockwise by 60 ° with respect to the case shown in FIG. As a result, the angle of the diffracted light incident on the objective lens 154 is further displaced counterclockwise by a rotation angle of 60 °, so that the direction of the interference fringes is further displaced counterclockwise by a rotation angle of 60 °. In this way, the drive control unit 160 controls the direction of the interference fringes.

That is, the drive control unit 160 drives the light beam generation unit 110 and the phase providing unit 120 to change the direction of the interference fringes when the phase difference is a predetermined phase difference.

Also in the state shown in FIG. 9A, as in the state shown in FIGS. 7A and 8A, after the diffracted light starts to pass through the passage portion AT, the shutter member 131 continuously 20 During the rotation, the diffracted light continues to pass through the passing portion AT. Specifically, the shutter member 131 is continuously rotated so that the reference point P reaches the rotation angle 120 ° and the reference point P reaches the rotation angle 140 ° until the reference angle P reaches the rotation angle 120 °. The incident diffracted light L3-1 continues to pass through the first passage portion ATa. Similarly, the diffracted light L3-2 incident on the rotation angle 300 ° from the reference point P reaching the rotation angle 120 ° to the reference point P reaching the rotation angle 140 ° Continue to pass through the passing portion ATb.
Further, when the transmission member 141 is continuously rotated, the light enters the position at the rotation angle of 120 ° from the time when the reference point Q reaches the rotation angle of 100 ° until the reference point Q reaches the rotation angle of 140 °. The diffracted light L3-1 continues to pass through the second region 122. Similarly, the diffracted light L3-2 incident on the rotation angle 300 ° from the reference point Q reaching the rotation angle 100 ° until the reference point Q reaches the rotation angle 140 ° is the first diffracted light L3-2. It continues to pass through the region 121.
Therefore, the diffracted light L3-1 passes through the first passage portion ATa and the second region 122 until the reference point P reaches the rotation angle 140 ° after the reference point P reaches the rotation angle 120 °. Subsequently, the diffracted light L3-2 continues to pass through the second passage portion ATb and the first region 121.

[Synchronous control of interference fringe direction and phase]
FIG. 10 is a sequence diagram illustrating an example of a control sequence by the drive control unit 160 of the present embodiment. The drive control unit 160 drives the shutter member 131 and the transmission member 141 to rotate in synchronization with the exposure operation (or imaging operation) of the imaging unit 210.

The drive control unit 160 rotationally drives the shutter member 131 at a predetermined rotational speed in accordance with the exposure operation of the imaging unit 210. As a result, the rotation angle of the passing portion AT of the shutter member 131 changes, and the diffracted light L1, the diffracted light L2, and the diffracted light L3 sequentially pass through the shutter member 131. Here, the shutter member 131 includes a passage portion AT having a predetermined size. For this reason, when the shutter member 131 continues to rotate, the diffracted light continuously passes for a predetermined period. Hereinafter, the shutter member 131 includes a passage portion AT having a central angle of 20 °, and the transmission member 141 includes a second region 122 having a central angle of 40 °. I will explain it. Here, an angle formed by two radii passing through both ends of the arc of the second region 122 of the transmissive member 141 is defined as a central angle of the second region 122.

First, the control operation of the drive control unit 160 at the timings T1 to T3 will be described. At timings T1 to T3, the drive control unit 160 drives the shutter member 131 and the transmission member 141 to rotate by matching the rotation speed of the shutter member 131 with the rotation speed of the transmission member 141.
Specifically, the drive control unit 160 rotationally drives the shutter member 131 so that the shutter member 131 has a rotation angle of 0 ° at timing T1, which is the first exposure start timing of the imaging unit 210. That is, at timing T1, the drive control unit 160 rotates the shutter member 131 so that the position of the reference point P of the shutter member 131 coincides with the position of the rotation angle 0 ° as shown in FIG. To drive. Further, the drive control unit 160 starts the shutter member from the timing T1 so that the position of the reference point P of the shutter member 131 becomes a rotation angle of 20 ° at the timing T1 ′ that is the first exposure end timing of the imaging unit 210. 131 is continuously rotated. That is, the drive control unit 160 rotationally drives the shutter member 131 so that the position of the reference point P of the shutter member 131 coincides with the position of the rotation angle of 20 ° at the timing T1 ′. As described above, since the shutter member 131 includes the passage portion AT having a central angle of 20 °, the diffracted light L1 passes through the shutter member 131 between the timing T1 and the timing T1 ′.

At this time, the drive control unit 160 rotationally drives the transmissive member 141 so that the position of the reference point Q of the transmissive member 141 is 0 ° at the timing T1. That is, at timing T1, the drive control unit 160 rotates the transmission member 141 so that the position of the reference point Q of the transmission member 141 coincides with the position of the rotation angle 0 ° as shown in FIG. To drive. Further, the drive controller 160 rotationally drives the transmissive member 141 so that the position of the reference point Q of the transmissive member 141 becomes a rotation angle of 20 ° at the timing T1 '. That is, the drive control unit 160 continuously drives the transmission member 141 to rotate from timing T1 so that the position of the reference point Q of the transmission member 141 coincides with the position of the rotation angle of 20 ° at the timing T1 ′. . As described above, the transmissive member 141 includes the second region 122 having a central angle of 40 °. For this reason, the diffracted light L1-1 passes through the second region 122 and the diffracted light L1-2 passes through the first region 121 between timing T1 and timing T1 '. Therefore, during the exposure of the imaging unit 210 (between timing T1 and timing T1 ′), the shutter member 131 and the transmission member 141 are continuously rotated by the drive control unit 160, but interference formed in the illumination area LA. The direction and phase of the stripes are constant.

The drive control unit 160 continuously drives the shutter member 131 to rotate from timing T1 ′ so that the shutter member 131 has a rotation angle of 60 ° at timing T2, which is the second exposure start timing of the imaging unit 210. To do. That is, at timing T2, the drive control unit 160 rotates the shutter member 131 such that the position of the reference point P of the shutter member 131 coincides with the position of the rotation angle 60 ° as shown in FIG. The shutter member 131 is rotationally driven without stopping. Further, the drive control unit 160 continuously rotates the shutter member 131 from timing T2 so that the shutter member 131 has a rotation angle of 80 ° at timing T2 ′ that is the second exposure end timing of the imaging unit 210. To do. That is, the drive control unit 160 makes the shutter member 131 stop at the timing T2 ′ without stopping the rotation of the shutter member 131 so that the position of the reference point P of the shutter member 131 coincides with the position of the rotation angle of 80 °. Is driven to rotate. Accordingly, the diffracted light L2 passes through the shutter member 131 between the timing T2 and the timing T2 '.

At this time, the drive controller 160 continuously rotates the transmission member 141 from timing T1 'so that the transmission member 141 has a rotation angle of 60 ° at timing T2. That is, at timing T2, the drive control unit 160 rotates the transmission member 141 so that the position of the reference point Q of the transmission member 141 coincides with the position of the rotation angle 60 ° as shown in FIG. The transmission member 141 is rotationally driven without stopping. Further, the drive control unit 160 continuously drives the transmission member 141 to rotate from timing T2 so that the transmission member 141 has a rotation angle of 80 ° at timing T2 '. That is, the drive control unit 160 makes the transmission member 141 stop the rotation of the transmission member 141 so that the position of the reference point Q of the transmission member 141 coincides with the position of the rotation angle of 80 ° at the timing T2 ′. Is driven to rotate. Thus, the diffracted light L2-1 passes through the second region 122 and the diffracted light L2-2 passes through the first region 121 between the timing T2 and the timing T2 '. Therefore, during the exposure of the imaging unit 210 (between timing T2 and timing T2 ′), the shutter member 131 and the transmission member 141 are continuously rotated by the drive control unit 160, but interference formed in the illumination area LA. The direction and phase of the stripes are constant.

The drive control unit 160 continuously drives the shutter member 131 to rotate from timing T2 ′ so that the shutter member 131 has a rotation angle of 120 ° at timing T3, which is the third exposure start timing of the imaging unit 210. To do. That is, at timing T3, the drive control unit 160 rotates the shutter member 131 such that the position of the reference point P of the shutter member 131 coincides with the position of the rotation angle 120 ° as shown in FIG. The shutter member 131 is rotationally driven without stopping.

At this time, the drive controller 160 continuously rotates the transmission member 141 from timing T2 'so that the transmission member 141 has a rotation angle of 120 ° at timing T3. That is, at timing T3, the drive control unit 160 rotates the transmission member 141 so that the position of the reference point Q of the transmission member 141 coincides with the position of the rotation angle 120 ° as shown in FIG. The transmission member 141 is rotationally driven without stopping.

When the timing of performing the exposure operation of the imaging unit 210 is a constant time interval, the drive control unit 160 drives the shutter member 131 to rotate at a constant rotational speed, so that the diffracted lights L1 to L3 are emitted from the shutter member. The timing of passing through 131 can be synchronized with the timing of the imaging unit 210 performing the exposure operation.

Next, the control operation of the drive control unit 160 at timings T3 to T7 will be described. The timings T3 to T7 differ from the controls at timings T1 to T3 in that the drive control unit 160 performs control to rotate the transmission member 141 at a speed lower than the rotation speed of the shutter member 131.

When reaching the timing T <b> 3, the drive control unit 160 rotates the transmission member 141 at a speed that is ¼ of the rotation speed of the shutter member 131. In addition, the drive control unit 160 performs the shutter member 131 between the timing T3 ′ and the timing T4 ′ that is the fourth exposure end timing of the imaging unit 210 in the same manner as the control between the timings T1 to T3 described above. Drive.
Specifically, the drive control unit 160 continuously moves the shutter member 131 from the timing T3 so that the rotation angle of the shutter member 131 is 140 ° at the timing T3 ′ that is the third exposure end timing of the imaging unit 210. To rotate. That is, the drive control unit 160 makes the shutter member 131 stop at the timing T3 ′ without stopping the rotation of the shutter member 131 so that the position of the reference point P of the shutter member 131 coincides with the position of the rotation angle 140 °. Is driven to rotate. Accordingly, the diffracted light L3 passes through the shutter member 131 between the timing T3 and the timing T3 ′.
At this time, the drive control unit 160 continuously rotates the transmission member 141 from timing T3 so that the transmission member 141 has a rotation angle of 125 ° at timing T3 ′. That is, the drive control unit 160 makes the transmission member 141 stop the rotation of the transmission member 141 so that the position of the reference point Q of the transmission member 141 coincides with the position of the rotation angle 125 ° at the timing T3 ′. Is driven to rotate. Thereby, the diffracted light L3-1 passes through the second region 122 and the diffracted light L3-2 passes through the first region 121 between the timing T3 and the timing T3 ′. Therefore, during the exposure of the imaging unit 210 (between timing T3 and timing T3 ′), the shutter member 131 and the transmission member 141 are continuously rotated by the drive control unit 160, but interference formed in the illumination area LA. The direction and phase of the stripes are constant.

Further, the drive control unit 160 continuously rotates and drives the shutter member 131 from the timing T3 ′ so that the shutter member 131 has a rotation angle of 180 ° at the timing T4. That is, the drive control unit 160 at the timing T4 that is the fourth exposure start timing of the imaging unit 210, as shown in FIG. 7B, the position of the reference point P of the shutter member 131 and the position of the rotation angle of 180 °. So that the shutter member 131 is rotated without stopping the rotation of the shutter member 131. Further, the drive control unit 160 drives the shutter member 131 to rotate continuously low from timing T4 so that the shutter member 131 has a rotation angle of 200 ° at timing T4 ′, which is the fourth exposure end timing of the imaging unit 210. To do. That is, the drive control unit 160 makes the shutter member 131 stop at the timing T4 ′ without stopping the rotation of the shutter member 131 so that the position of the reference point P of the shutter member 131 coincides with the position of the rotation angle of 200 °. Is driven to rotate. Thereby, the diffracted light L1 passes through the shutter member 131 between the timing T4 and the timing T4 ′.
At this time, the drive control unit 160 continuously rotates the transmission member 141 from timing T3 ′ so that the transmission member 141 has a rotation angle of 135 ° at timing T4. That is, at timing T4, the drive control unit 160 causes the position of the reference point Q of the transmission member 141 and the position of the rotation angle 135 ° to coincide with each other without stopping the rotation of the transmission member 141. Rotation drive. Furthermore, the drive control unit 160 continuously drives the transmission member 141 to rotate from timing T4 so that the transmission member 141 has a rotation angle of 140 ° at timing T4 ′. That is, at timing T4 ′, the drive control unit 160 makes the position of the reference point Q of the transmission member 141 coincide with the position of the rotation angle of 140 ° without stopping the rotation of the transmission member 141. Is driven to rotate. Thereby, both the diffracted light L1-1 and the diffracted light L1-2 pass through the first region 121 between the timing T4 and the timing T4 ′. Therefore, during the exposure of the imaging unit 210 (between timing T4 and timing T4 ′), the shutter member 131 and the transmission member 141 are continuously rotated by the drive control unit 160, but interference formed in the illumination area LA. The direction and phase of the stripes are constant.

In addition, the drive control unit 160 continuously drives the shutter member 131 to rotate from timing T4 ′ so that the shutter member 131 has a rotation angle of 240 ° at timing T5 which is the fifth exposure start timing of the imaging unit 210. To do. That is, at timing T5, the drive controller 160 rotates the shutter member 131 so that the position of the reference point P of the shutter member 131 coincides with the position of the rotation angle of 180 ° as shown in FIG. 8B. The shutter member 131 is rotationally driven without stopping. Further, the drive control unit 160 continuously rotates the shutter member 131 from timing T5 so that the shutter member 131 has a rotation angle of 260 ° at timing T5 ′ that is the fifth exposure end timing of the imaging unit 210. To do. That is, the drive control unit 160 makes the position of the reference point P of the shutter member 131 coincide with the position of the rotation angle 260 ° at the timing T5 ′ so that the rotation of the shutter member 131 is not stopped. Is driven to rotate. Thereby, the diffracted light L2 passes through the shutter member 131 between the timing T5 and the timing T5 ′.
At this time, the drive control unit 160 continuously rotates the transmission member 141 from timing T4 ′ so that the transmission member 141 has a rotation angle of 150 ° at timing T5. That is, at timing T4, the drive control unit 160 causes the position of the reference point Q of the transmissive member 141 and the position of the rotation angle 150 ° to coincide with each other without stopping the rotation of the transmissive member 141. Rotation drive. Furthermore, the drive control unit 160 continuously rotates the transmission member 141 from timing T5 so that the transmission member 141 has a rotation angle of 155 ° at timing T5 ′. That is, at timing T5 ′, the drive control unit 160 makes the position of the reference point Q of the transmission member 141 coincide with the position of the rotation angle 155 ° without stopping the rotation of the transmission member 141. Is driven to rotate. Thus, both the diffracted light L1-1 and the diffracted light L1-2 pass through the first region 121 between the timing T5 and the timing T5 ′. Therefore, during exposure of the imaging unit 210 (between timing T5 and timing T5 ′), the shutter member 131 and the transmission member 141 are continuously rotated by the drive control unit 160, but interference formed in the illumination area LA. The direction and phase of the stripes are constant.

Further, the drive control unit 160 continuously drives the shutter member 131 to rotate from timing T5 ′ so that the shutter member 131 has a rotation angle of 300 ° at timing T6, which is the sixth exposure start timing of the imaging unit 210. To do. That is, at timing T6, the drive control unit 160 rotates the shutter member 131 so that the position of the reference point P of the shutter member 131 coincides with the position of the rotation angle 300 ° as shown in FIG. 9B. The shutter member 131 is rotationally driven without stopping. Further, the drive control unit 160 continuously rotates and drives the shutter member 131 from the timing T6 so that the shutter member 131 has a rotation angle of 320 ° at the timing T6 ′ that is the sixth exposure end timing of the imaging unit 210. To do. That is, the drive control unit 160 makes the shutter member 131 stop at the timing T6 ′ without stopping the rotation of the shutter member 131 so that the position of the reference point P of the shutter member 131 coincides with the position of the rotation angle of 320 °. Is driven to rotate. Accordingly, the diffracted light L3 passes through the shutter member 131 between the timing T6 and the timing T6 ′.
At this time, the drive control unit 160 continuously drives the transmission member 141 from timing T5 ′ so that the transmission member 141 has a rotation angle of 165 ° at timing T6. That is, at timing T6, the drive control unit 160 causes the position of the reference point Q of the transmission member 141 and the position of the rotation angle of 165 ° to coincide with each other without stopping the rotation of the transmission member 141. Rotation drive. Further, the drive control unit 160 continuously drives the transmission member 141 to rotate from timing T6 so that the transmission member 141 has a rotation angle of 170 ° at timing T6 ′. That is, at timing T6 ′, the drive control unit 160 makes the position of the reference point Q of the transmission member 141 coincide with the position of the rotation angle of 170 ° without stopping the rotation of the transmission member 141. Is driven to rotate. Thereby, the diffracted light L1-1 and the diffracted light L1-2 pass through the first region 121 between the timing T6 and the timing T6 ′. Therefore, during the exposure of the imaging unit 210 (between timing T6 and timing T6 ′), the shutter member 131 and the transmission member 141 are continuously rotated by the drive control unit 160, but interference formed in the illumination area LA. The direction and phase of the stripes are constant.

The control operation of the drive control unit 160 at timings T7 to T9 'is the same as the control at timings T1 to T3'. That is, at the timings T7 to T9 ′, the shutter member 131 and the transmission member 141 are synchronized with each other except that the phase difference between the + 1st order diffracted light and the −1st order diffracted light emitted at the timings T1 to T3 ′ is opposite to each other. This is the same in that it is controlled. Therefore, detailed description of the control operation of the drive control unit 160 at the timings T7 to T9 'is omitted.

Then, the calculation unit 220 generates nine images of the specimen SP on which nine types of interference fringes having different directions and phase differences are projected, and generates a super-resolution image from the nine images generated by a known method. To do. The rotation drive of the shutter member 131 and the transmission member 141 by the drive control unit 160 is continued without stopping until the imaging unit 210 captures all nine types of specimen SP images. In addition, if the time until generation of a super-resolution image from nine images is short, the rotation of the shutter member 131 and the transmission member 141 by the drive control unit 160 causes the calculation unit 220 to perform super-resolution from the nine images. In other words, it can be continued until an image is generated.

In this way, the drive control unit 160 drives the light beam generation unit 110 and the phase providing unit 120 to set one of the first light beam and the second light beam to the first region 121 (reference). The incident position in the first region 121 (reference phase region) and the incident position in the phase modulation region 122 are changed while the other light beam is incident on the phase modulation region 122. Thus, the direction of the interference fringes is changed when the phase difference is a predetermined phase difference.

Further, in this way, the drive control unit 160 rotates the light beam generation unit 110 about the optical axis of the illumination optical system 150 (interference optical system) as a rotation center, so that the first along the optical axis. The direction of the interference fringes is controlled by changing the optical path between the light beam and the second light beam.

As described above, the observation apparatus 1 according to the present embodiment drives the light flux generation unit 110 and the phase providing unit 120, and controls the drive control unit 160 that controls at least one of the direction of interference fringes and the phase difference. I have. The drive control unit 160 drives the light beam selecting unit and the phase applying unit 120 to cause at least one of the first light beam and the second light beam to enter the phase applying unit 120 and to cause the phase applying unit 120 to enter the phase applying unit 120. By changing the upper position, the direction of the interference fringes is changed when the previous phase difference is a predetermined phase difference. By providing this drive control unit 160, the observation apparatus 1 has the following effects.

That is, the drive control unit 160 drives the shutter member 131 and the transmission member 141 to rotate continuously. Accordingly, the drive control unit 160 performs control to switch the diffracted lights L1 to L3 emitted to the objective lens 154 to each other. At this time, the drive control unit 160 switches the diffracted light without stopping the rotation of the shutter member 131 and the transmission member 141. Here, as in the past, after stopping the rotating shutter member 131 and the transmission member 141, an interference fringe in a predetermined direction that interferes with a predetermined phase difference is formed on the sample SP to capture an image of the sample SP. (For example, change the direction of the interference fringe by ± 1st order diffracted light in 3 directions, and change the phase difference of ± 1st order diffracted light into 3 types of fast, in-phase, and slow phase for each direction) In the case where a super-resolution image is generated from a plurality of obtained images (for example, nine images), the rotating shutter member 131 and the transmissive member 141 are stopped. And the time required to accelerate the stopped shutter member 131 and transmission member 141 to a desired rotational speed, the time until the super-resolution image is generated becomes longer and the observation efficiency becomes lower. The drive control unit 160 included in the observation apparatus 1 can switch the phase difference of the beam bundle to be interfered and the direction of the interference fringes without stopping the rotation of the shutter member 131 and the transmission member 141, and thus the shutter member 131. In addition, since it does not take time to stop and accelerate the transmission member 141, it is possible to shorten the time until the generation of the super-resolution image, and to efficiently observe the specimen SP.

Further, the drive controller 160 continuously rotates the shutter member 131 and the transmissive member 141 while changing the rotation speed of the transmissive member 141. Specifically, the drive controller 160 continuously rotates and drives the shutter member 131 at the same time between the timings T1 and T3 with the rotational speed of the shutter member 131 and the rotational speed of the transmission member 141 matched. In addition, the drive control unit 160 continuously drives the transmission member 141 to rotate at a speed that is ¼ of the rotation speed of the shutter member 131 between the timings T3 and T7. The drive control unit 160 drives to rotate continuously with the rotation speed of the shutter member 131 and the rotation speed of the transmission member 141 matched between the timings T7 to T9 ′. As described above, the drive controller 160 changes the direction of the interference fringes by ± first-order diffracted light into the three directions diffracted by the periodic structure of the first direction D1 to the third direction D3, and the interference fringes in each direction. The phase difference of the ± first-order diffracted light is changed into three types: fast phase, in-phase, and slow phase. That is, the drive control unit 160 changes nine combinations of the direction of the interference fringes and the phase difference of the diffracted light. Here, when the rotation speed of the transmission member 141 is not variable, in order to change the direction of the interference fringe and the phase difference of the diffracted light in nine ways, at least one of the shutter member 131 and the transmission member 141 is used. There is a period during which the rotation of the motor stops. In this case, a time from the rotating state to the stop and a time to accelerate from the stopped state to the desired speed are required, so the time to generate the super-resolution image is required. become longer. Therefore, the sample SP cannot be observed efficiently. The drive control unit 160 of the present embodiment determines the phase difference of the diffracted light and the direction of the interference fringes due to the diffracted light while rotating and driving at a variable speed without stopping the shutter member 131 and the transmissive member 141. Can be changed. Therefore, according to the observation apparatus 1, since the super-resolution image can be generated without stopping the shutter member 131 and the transmission member 141, the specimen SP can be observed efficiently.
In this example, the case where only the rotation speed of the transmission member 141 is variable has been described. However, the drive control unit 160 may change the rotation speed of at least one of the shutter member 131 and the transmission member 141. The above-described effects can be achieved. Further, the rotational speeds of both the shutter member 131 and the transmission member 141 may be variable.

Also, in so-called live cell imaging for observing live cells, conventionally, it took a long time to generate a super-resolution image, so if the live cells move before generating a super-resolution image, the desired resolution is achieved. A super-resolution image could not be obtained. On the other hand, since the observation apparatus 1 can shorten the time required to generate a super-resolution image, even a living cell that has been fast moving and has not been able to obtain a desired resolution until now has its super-resolution. An image can be generated at a desired resolution.

[Modification]
Next, a modified example of the shutter member 131 will be described. FIG. 11A and FIG. 11B are perspective views showing modifications of the shutter member 131, respectively. As for the shutter member 131 shown to Fig.11 (a), each planar shape of 1st passage part ATa and 2nd passage part ATb is circular. As the distance from the rotation axis AX3 in the radial direction from the rotation axis AX3, the first passage portion ATa and the second passage portion ATb increase in size in the direction orthogonal to the radial direction, and then decrease after the size becomes maximum. . In the shutter member 131 shown in FIG. 11B, the planar shape of each of the first passage portion ATa and the second passage portion ATb is a fan shape. The first passage portion ATa and the second passage portion ATb are disposed up to the outer periphery of the shutter member 131, respectively. Thus, the shape of the first passage portion ATa and the shape of the second passage portion AT can be changed as appropriate.

Next, a modified example of the lighting device 10 will be described. FIG. 12 is a diagram illustrating a schematic configuration of a lighting device 10 according to a modification. FIG. 12 shows components disposed in the optical path from the light source device 100 to the shutter member 131.

The illumination device 10 of the present modification includes a wave plate 140A that changes the polarization state of the light beam generated by the diffraction grating 111 to linearly polarized light. The illumination optical system 150 generates interference fringes by converting the light beam, which is converted into linearly polarized light by the wave plate 140A, into S-polarized light in the vicinity of the specimen SP shown in FIG.

In FIG. 12, the light emitted from the light source device 100 is, for example, first linearly polarized light whose polarization direction is a direction PD1 shown in FIG. The illumination device 10 converts the first linearly polarized light whose direction is the direction PD1 into second linearly polarized light having a polarization direction different from that of the first linearly polarized light, and illuminates the illumination area LA with the illumination light IL of the second linearly polarized light. . The polarization direction of the second linearly polarized light is, for example, a direction PD2 shown in FIG. Here, the first linearly polarized light is the linearly polarized light shown in FIG. 1 and the like, and the second linearly polarized light is S-polarized light with respect to the specimen SP.

The illumination device 10 includes a quarter wavelength plate 142 and a quarter wavelength plate 143. In this illuminating device 10, the shutter member 131 is disposed in the optical path between the diffraction grating 111 and the relay lens 152 shown in FIG. The quarter wavelength plate 142 is disposed in the optical path between the light source device 100 and the diffraction grating 111. The quarter wave plate 142 has a fixed rotation angle relative to the polarization direction of the first linearly polarized light from the light source. The fast axis or slow axis (axis AXa shown in FIG. 12) of the quarter wavelength plate 142 is arranged at an angle of about 45 ° with respect to the polarization direction of the first linearly polarized light. Light from the light source 101 is converted into circularly polarized light through the quarter-wave plate 142 and is incident on the diffraction grating 111.

The quarter wave plate 143 is at least a part of the wave plate 140B. The relative rotation angle of the quarter-wave plate 143 with respect to the shutter member 131 is fixed. In this modification, the shutter member 131 can rotate, and the quarter-wave plate 143 can rotate in synchronization with the shutter member 131. The quarter wavelength plate 143 is disposed at a position away from the shutter member 131 and is driven by a drive unit different from the shutter member 131. The drive unit of the quarter-wave plate 143 is controlled by the drive control unit 160 shown in FIG. 1 so that the relative rotation angle between the quarter-wave plate 143 and the passage part AT of the shutter member 131 is maintained. The quarter wave plate 143 is driven to rotate. The fast axis or slow axis (axis AXb shown in FIG. 12) of the quarter-wave plate 143 is relative to the line connecting the center of the first passage portion ATa and the center of the second passage portion ATb of the shutter member 131. It is arranged at an angle of about 45 °. The diffracted light diffracted by the diffraction grating 111 is circularly polarized light, is transmitted through the quarter-wave plate 143, and is converted to S-polarized light with respect to the specimen SP.

The driving unit of the shutter member 131 may include at least a part of the driving unit of the quarter wavelength plate 143. Further, the quarter wavelength plate 143 may be attached to the shutter member 131, and the relative position to the shutter member 131 may be fixed.

As described above, the illumination device 10 includes the linear polarization unit that changes the polarization state of the light beam generated by the light beam generation unit 110 to linearly polarized light. Further, the illumination optical system 150 (interference optical system) generates an interference fringe by converting the light beam, which has been linearly polarized by the linearly polarized light portion, into S-polarized light in the vicinity of the sample. The illumination device 10 can improve the contrast of the interference fringes in the vicinity of the sample by using the S-polarized light beam.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. Note that the description of the configuration and operation that are the same as those of the first embodiment described above is simplified or omitted.
FIG. 13 is a diagram showing an observation apparatus 1a according to the second embodiment, and FIG. 14 is a diagram showing a diffraction grating 111 according to this embodiment. The observation device 1a of the present embodiment is different from the first embodiment in the configuration of the illumination device 10a. The observation apparatus 1a of the present embodiment is different from the first embodiment in that the illumination apparatus 10a includes a diffraction grating 112 having a periodic structure in one direction instead of a plurality of directions.
Further, +1 is diffracted by the diffraction grating 112 along the periphery of the optical axis AX1 of the illumination optical system 150, not the passage portion AT (the first passage portion ATa and the second passage portion ATb) having a shape like the shutter member 131. The second embodiment is different from the first embodiment in that a shutter member 133 having a circular opening passing portion (not shown) that allows the passage of the first-order diffracted light and the minus first-order diffracted light is provided. The illumination device 10a of the present embodiment is different from the first embodiment in that the illumination device 10a includes a drive control unit 160a that does not rotate the shutter member 133 but rotates the diffraction grating 112 and the transmission member 141. Note that the zero-order diffracted light from the diffraction grating 112 is shielded by the shutter member 133. Note that the shape of the passage portion (not shown) of the shutter member 133 is not limited to the annular opening, and it is only necessary to have a passage portion that shields the 0th-order diffracted light and allows the ± 1st-order diffracted light to pass.

As shown in FIG. 14, the diffraction grating 112 has a periodic structure in one direction, and divides an incident light bundle into a plurality of light bundles including a first light bundle and a second light bundle distributed along one direction. To do. That is, the diffraction grating 112 is a one-way diffraction grating having one diffraction direction. The diffraction grating 112 can rotate around the rotation axis AX5. In the present embodiment, the rotation axis AX5 of the diffraction grating 112 is coaxial with the optical axis AX1 of the illumination optical system 150.

The diffraction grating 112 is rotated by torque supplied from a drive unit (not shown) such as an electric motor. This drive unit is controlled by the drive control unit 160 a to rotate the diffraction grating 112. The drive control unit 160 a can control the rotation angle of the diffraction grating 112 by controlling the drive unit of the diffraction grating 112.

FIG. 15 is a diagram showing the position of the spot light on the conjugate plane OS1 formed by condensing each diffracted light diffracted by the diffraction grating 112. FIG. As shown in FIG. 15, the spot position D1 of the + 1st order diffracted light is point-symmetric with respect to the position D2 of the spot of the −1st order diffracted light with respect to the optical axis AX1 of the illumination optical system 150. The spot position D1 of the + 1st order diffracted light and the position D2 of the spot of the −1st order diffracted light are maintained in point symmetry with respect to the optical axis AX1 of the illumination optical system 150 as the diffraction grating 112 rotates, while maintaining the optical axis AX1. Changes to rotate around.

Returning to the description of FIG. 13, the transmission member 141 is rotatable as described in the first embodiment. The drive control unit 160 a can control the relative rotation angle between the diffraction grating 112 and the transmission member 141 by controlling the drive unit of the diffraction grating 112 and the drive unit of the transmission member 141. The transmitting member 141 is disposed at the position of the conjugate plane OS1, and the spot position D1 of the + 1st order diffracted light and the position D2 of the spot of the −1st order diffracted light shown in FIG. Correspond. That is, the position of the spot on the transmission member 141 changes according to the relative rotation angle between the diffraction grating 112 and the transmission member 141.

As shown in FIG. 5 and the like, the transmission member 141 has a second region 122 and a first region 121. The drive control unit 160a controls the relative rotation angle between the diffraction grating 112 and the transmissive member 141, so that the region where the spot light of the diffracted light is formed in the transmissive member 141 is the second region 122 and the first region. 121 can be switched. For example, the drive control unit 160a may set the relative rotation angle between the diffraction grating 112 and the transmission member 141 so that both the spot light of the + 1st order diffracted light and the spot light of the −1st order diffracted light are arranged in the first region 121. Can be controlled. Further, the drive control unit 160a includes the diffraction grating 112 and the transmission member 141 so that the spot light of the + 1st order diffracted light is formed in the second region 122 and the spot light of the −1st order diffracted light is formed in the first region 121. Relative rotation angle can be controlled. Since the optical distance in the thickness direction of the transmission member 141 differs between the second region 122 and the second region, the drive control unit 160a controls the phase difference between the + 1st order diffracted light and the −1st order diffracted light that have passed through the transmission member 141. it can. A specific example in which the drive control unit 160a controls the phase difference between the + 1st order diffracted light and the −1st order diffracted light will be described with reference to FIG.

FIG. 16 is a schematic diagram illustrating an example of a positional relationship between the light beam generation unit 110 and the phase providing unit 120 of the present embodiment. The drive control unit 160a rotationally drives the diffraction grating 112 so that the diffracted light is incident on the positions shown in FIG. 16A (for example, the positions having a rotation angle of 0 ° and a rotation angle of 180 °). As a result, of the two diffracted lights emitted from the diffraction grating 112, the diffracted light L1-1 incident on the rotation angle of 0 ° is transmitted through the second region 122 and the phase thereof is modulated. The modulated diffracted light L1-1 ′ is obtained. Further, the diffracted light L1-2 incident on the rotation angle of 180 ° is transmitted through the first region 121. In this way, the phase imparting unit 120 imparts a phase difference between the diffracted light L1-1 and the diffracted light L1-2 having the same phase.

Next, referring to FIG. 16 (b), the drive control unit 160a does not change the rotation angle of the diffraction grating 112, and rotates the transmission member 141 counterclockwise with respect to the traveling direction of the light bundle by 90 °. A case of rotational driving will be described. The drive control unit 160a rotationally drives the transmissive member 141 so that the second region 122 of the transmissive member 141 is disposed at the position illustrated in FIG. As a result, the two diffracted lights L1-1 and L1-2 are both transmitted through the first region 121. Therefore, the phases of the diffracted light L1-1 and the diffracted light L1-2 are the same even after transmission through the transmission member 141. This is different from the case shown in FIG. 16A, that is, the case where there is a phase difference between the diffracted light L1-1 ′ and the diffracted light L1-2 after being transmitted through the transmitting member 141, in terms of the presence or absence of the phase difference. To do.

Next, referring to FIG. 16C, the drive control unit 160a turns the transmission member 141 counterclockwise with respect to the traveling direction of the light bundle, and further rotates by 90 ° with respect to the case shown in FIG. The case where only rotational driving is performed will be described. The drive control unit 160a rotationally drives the transmissive member 141 so that the second region 122 of the transmissive member 141 is disposed at the position illustrated in FIG. As a result, the diffracted light L1-2 passes through the second region 122 and its phase is modulated, and becomes a diffracted light L1-2 'after phase modulation. Further, the diffracted light L1-1 passes through the first region 121. In this way, the phase applying unit 120 provides a phase difference between the diffracted light L1-1 and the diffracted light L1-2 having the same phase. This is because the diffracted light L1-1 ′ and the diffracted light L1-2 transmitted through the transmitting member 141 are the phase difference between the diffracted light and the phase-advanced phase as shown in FIG. It is different in that the relationship is reversed.

Up to this point, an example of a mechanism in which the drive control unit 160a controls the phase difference of the interference fringes has been described with reference to FIGS. 16 (a) to 16 (c). Next, an example of a mechanism by which the drive control unit 160a controls the direction of the interference fringes will be described with reference to FIG.

FIG. 17 is a schematic diagram illustrating an example of the direction of interference fringes controlled by the drive control unit 160a of the present embodiment. The drive control unit 160a controls the direction of the interference fringes by rotating and driving the diffraction grating 112 and the transmission member 141 in synchronization. Specifically, the drive controller 160a drives the diffraction grating 112 and the transmission member 141 to rotate in a counterclockwise direction with respect to the traveling direction of the light beam. At this time, the position at which each diffracted light emitted from the diffraction grating 112 enters the transmission member 141 changes as the diffraction grating 112 rotates. For this reason, when the diffraction grating 112 and the transmission member 141 are rotated counterclockwise and the rotation angle changes from 0 ° to 120 °, the position of the diffracted light emitted from the transmission member 141 is counterclockwise. (See FIG. 17B). As a result, the position of the diffracted light incident on the objective lens 154 is displaced 120 ° counterclockwise, so that the direction of the interference fringes is displaced 120 ° counterclockwise.

Further, when the diffraction grating 112 and the transmission member 141 are driven to rotate counterclockwise and the rotation angle changes from 120 ° to 240 °, the position of the diffracted light emitted from the transmission member 141 is further counterclockwise. (See FIG. 17C). As a result, the position of the diffracted light incident on the objective lens 154 is further displaced by 120 ° counterclockwise, so that the direction of the interference fringes is further displaced by 120 ° counterclockwise. In this way, the drive control unit 160a controls the direction of the interference fringes.

[Synchronous control of interference fringe direction and phase]
The drive controller 160a changes the direction and phase of the interference fringes by continuously rotating the diffraction grating 112 and the transmission member 141 described above without stopping them. Here, when the diffraction grating 112 is continuously rotated without being stopped, a period in which diffracted light emitted from the diffraction grating 112 is generated in a direction other than a desired direction is generated. The illumination device 10a includes a diaphragm member 155 that blocks light so that light from the relay lens 152 does not enter the illumination area LA during a period in which diffracted light emitted from the diffraction grating 112 is generated in a direction other than a desired direction. ing.

In the present embodiment, the diaphragm member 155 can change one or both of the shape and size of the region through which the light from the relay lens 152 passes. The drive controller 160a can block the light from the relay lens 152 at an arbitrary timing by controlling the diaphragm member 155.

For example, the drive controller 160a may block the light from the relay lens 152 by the diaphragm member 155 so that the light from the relay lens 152 does not enter the illumination area LA at the timing when the diffraction grating 112 is arranged at a rotation angle other than desired. it can. Accordingly, the drive control unit 160a can block diffracted light in a diffraction direction other than desired so as not to enter the illumination area LA. As described above, the diaphragm member 155 can block at least a part of the light bundles generated by the diffraction grating 112 during the change of the interference fringes by the drive control unit 160a.

In addition, the drive control unit 160a receives the light from the relay lens 152 at the timing when the spot light formed by condensing the diffracted light on the transmission member 141 is arranged across the second region 122 and the first region 121. This light can be blocked by the diaphragm member 155 so as not to enter the illumination area LA. That is, the diaphragm member 155 can block at least a part of the light bundles generated by the diffraction grating 112 during the change from the phase difference by the drive control unit 160a.

That is, the illumination optical system 150 includes a light shielding unit that shields at least a part of the light bundles generated by the light bundle generation unit 110 during the change of the direction and phase of the interference fringes by the drive control unit 160a. I have.

The drive control unit 160a controls the diaphragm member 155 at a predetermined timing according to the exposure operation of the imaging unit 210, and continuously rotates and drives the diffraction grating 112 and the transmission member 141 without stopping. As a result, the direction and phase of the interference fringes are changed. Here, first, a case will be described in which the direction of the interference fringes is changed in three ways for the diffracted light L1-1 'and the diffracted light L1-2 that have a phase difference. Next, the case where the direction of the interference fringe is changed in three ways for the diffracted light L1-1 and the diffracted light L1-2 having the same phase will be described. Next, the case where the direction of the interference fringe is changed in three ways for the diffracted light L1-1 and the diffracted light L1-2 'having a phase difference will be described. Accordingly, the drive control unit 160a changes the combinations of the interference fringe direction and the phase difference of the diffracted light in nine ways.

First, the case where the direction of the interference fringe is changed in three ways for the diffracted light L1-1 ′ and the diffracted light L1-2 having a phase difference will be described. The drive controller 160a rotationally drives the diffraction grating 112 and the transmission member 141 so that the diffracted light is incident on the positions shown in FIG. 17A (for example, the positions of the rotation angle 0 ° and the rotation angle 180 °). To do. As a result, of the two diffracted lights emitted from the diffraction grating 112, the diffracted light L1-1 incident on the rotation angle of 0 ° is transmitted through the second region 122 and the phase thereof is modulated. The modulated diffracted light L1-1 ′ is obtained. Further, the diffracted light L1-2 incident on the rotation angle of 180 ° is transmitted through the first region 121. At this time, the drive controller 160a controls the diaphragm member 155 to cause the diffracted light L1-1 ′ and the diffracted light L1-2 to enter the illumination area LA.
Next, the drive controller 160a controls the diaphragm member 155 to shield the diffracted light L1-1 ′ and the diffracted light L1-2, and further stops both the diffraction grating 112 and the transmissive member 141. Without rotating continuously. The drive controller 160a controls the diaphragm member 155 to control the diffracted light L1-1 ′ and the diffracted light L1- at the timing when the diffraction grating 112 and the transmissive member 141 are displaced counterclockwise by 120 ° by this rotational drive. 2 enters the illumination area LA.
Next, the drive controller 160a controls the diaphragm member 155 to shield the diffracted light L1-1 ′ and the diffracted light L1-2, and further stops both the diffraction grating 112 and the transmissive member 141. Without rotating continuously. By this rotational drive, at the timing when the diffraction grating 112 and the transmission member 141 are further displaced by 120 ° counterclockwise, the drive control unit 160a controls the diaphragm member 155 to control the diffracted light L1-1 ′ and the diffracted light. L1-2 is made incident on the illumination area LA.
In this way, the drive control unit 160a changes the positions where the diffracted light L1-1 ′ and the diffracted light L1-2 having a phase difference from each other enter the illumination area LA in three ways.

Next, the case where the direction of the interference fringe is changed in three ways for the diffracted light L1-1 and the diffracted light L1-2 having the same phase will be described. The drive control unit 160a controls the diaphragm member 155 to block the diffracted light L1-1 ′ and the diffracted light L1-2, and continuously stops the diffraction grating 112 and the transmission member 141 without stopping them. Rotational drive. At this time, the drive control unit 160a increases the rotation speed of the transmission member 141 faster than the rotation speed of the diffraction grating 112, and continuously rotates the diffraction grating 112 and the transmission member 141 without stopping both. To drive. Specifically, the drive control unit 160a displaces the diffraction grating 112 and the transmission member 141 so as to displace the transmission member 141 by 210 degrees counterclockwise while the diffraction grating 112 is displaced 120 degrees counterclockwise. Rotation drive. Thereby, the diffraction grating 112 and the transmissive member 141 are in the state shown in FIG. That is, the two diffracted lights L1-1 and L1-2 incident on the transmissive member 141 are both transmitted through the first region 121. Therefore, the phases of the diffracted light L1-1 and the diffracted light L1-2 are the same even after transmission through the transmission member 141. At this time, the drive control unit 160a controls the diaphragm member 155 to cause the diffracted light L1-1 and the diffracted light L1-2 to enter the illumination area LA.
Next, the drive control unit 160a controls the diaphragm member 155 to shield the diffracted light L1-1 and the diffracted light L1-2, and further stops neither the diffraction grating 112 nor the transmissive member 141. To continuously rotate. At this time, the drive control unit 160a rotates the diffraction grating 112 and the transmission member 141 at the same rotational speed. At the timing when the diffraction grating 112 and the transmission member 141 are further displaced counterclockwise by 120 ° due to this rotational drive, the drive control unit 160a controls the diaphragm member 155 to control the diffracted light L1-1 and the diffracted light L1- 2 enters the illumination area LA.
Next, the drive control unit 160a controls the diaphragm member 155 to shield the diffracted light L1-1 and the diffracted light L1-2, and further stops neither the diffraction grating 112 nor the transmissive member 141. To continuously rotate. By this rotational drive, at the timing when the diffraction grating 112 and the transmission member 141 are further displaced by 120 ° counterclockwise, the drive control unit 160a controls the diaphragm member 155 to control the diffracted light L1-1 and the diffracted light L1. -2 is incident on the illumination area LA.
In this way, the drive control unit 160a changes the positions at which the diffracted light L1-1 and diffracted light L1-2 having the same phase are incident on the illumination area LA in three ways.

Next, the case where the direction of the interference fringe is changed in three ways for the diffracted light L1-1 and the diffracted light L1-2 ′ having a phase difference from each other will be described. The drive controller 160a controls the diaphragm member 155 to shield the diffracted light L1-1 and the diffracted light L1-2, and continuously stops the diffraction grating 112 and the transmissive member 141 without stopping them. To rotate. At this time, the drive control unit 160a increases the rotation speed of the transmission member 141 faster than the rotation speed of the diffraction grating 112, and continuously rotates the diffraction grating 112 and the transmission member 141 without stopping both. To drive. Specifically, the drive control unit 160a displaces the diffraction grating 112 and the transmission member 141 so as to displace the transmission member 141 by 210 degrees counterclockwise while the diffraction grating 112 is displaced 120 degrees counterclockwise. Rotation drive. Thereby, the diffraction grating 112 and the transmissive member 141 are in the state shown in FIG. That is, the diffracted light L1-2 passes through the second region 122 and its phase is modulated to become a diffracted light L1-2 ′ after phase modulation. Further, the diffracted light L1-1 passes through the first region 121. At this time, the drive controller 160a controls the diaphragm member 155 to cause the diffracted light L1-1 and the diffracted light L1-2 ′ to enter the illumination area LA.
Next, the drive control unit 160a controls the diaphragm member 155 to shield the diffracted light L1-1 and the diffracted light L1-2 ′, and further stops both the diffraction grating 112 and the transmissive member 141. Without rotating continuously. At this time, the drive control unit 160a rotates the diffraction grating 112 and the transmission member 141 at the same rotational speed. At the timing when the diffraction grating 112 and the transmission member 141 are further displaced counterclockwise by 120 ° due to this rotational drive, the drive control unit 160a controls the diaphragm member 155 to control the diffracted light L1-1 and the diffracted light L1- 2 'is made incident on the illumination area LA.
Next, the drive control unit 160a controls the diaphragm member 155 to shield the diffracted light L1-1 and the diffracted light L1-2 ′, and further stops both the diffraction grating 112 and the transmissive member 141. Without rotating continuously. By this rotational drive, at the timing when the diffraction grating 112 and the transmission member 141 are further displaced by 120 ° counterclockwise, the drive control unit 160a controls the diaphragm member 155 to control the diffracted light L1-1 and the diffracted light L1. -2 ′ is incident on the illumination area LA.
In this way, the drive control unit 160a changes the positions where the diffracted light L1-1 and the diffracted light L1-2 ′ having a phase difference from each other enter the illumination area LA in three ways.

Then, the calculation unit 220 generates nine images of the specimen SP on which nine types of interference fringes having different directions and phase differences are projected, and generates a super-resolution image from the nine images generated by a known method. To do. The rotation drive of the diffraction grating 112 and the transmission member 141 by the drive control unit 160a is continued without stopping until the imaging unit 210 captures all nine types of specimen SP images. In addition, if the time until generation of a super-resolution image from nine images is short, the rotational drive of the diffraction grating 112 and the transmission member 141 by the drive control unit 160a is performed by the calculation unit 220 from the nine images. In other words, it can be continued until an image is generated.

As described above, the observation apparatus 1a of the present embodiment includes the drive control unit 160a that drives the light beam generation unit 110 and the phase providing unit 120 to control the direction and phase of interference fringes. The light beam generation unit 110 of the observation apparatus 1a has a periodic structure in one direction, and diffracts the incident light beam into a plurality of light beams including a first light beam and a second light beam distributed in one direction. A grid 112 is provided. Further, the drive control unit 160a drives the diffraction grating 112 (light bundle splitting unit) and the phase applying unit 120 to cause at least one of the first light bundle or the second light bundle to enter the phase providing unit 120, and By changing the position on the phase applying unit 120 to be incident, the direction of the interference fringes is changed when the phase difference is a predetermined phase difference. By providing this drive control unit 160a, the observation apparatus 1a has the same effect as the observation apparatus 1.

In addition, the drive control unit 160a changes the direction of the interference fringes without stopping the rotation of the diffraction grating 112. Here, as in the conventional case, when stopping the rotating diffraction grating 112 or accelerating the stopped diffraction grating 112, a driving unit (not shown) particularly immediately before or after the rotation stops, For example, when a driving unit (not shown) vibrates due to backlash or the like, the vibration of the driving unit is transmitted to the diffraction grating 112, and the diffraction grating 112 vibrates. At this time, in the diffraction grating 112, particularly on the sample SP due to a vibration component along the rotation direction of the diffraction grating 112 or a vibration component in a direction parallel to the incident surface of the diffraction grating 112 on which the light beam from the light source 101 is incident. Since the contrast (S / N ratio) of the interference fringes formed in the image quality decreases, the resolution of the super-resolution image decreases. Therefore, in order to capture an image in which interference fringes with sufficient contrast are formed on the specimen SP, it is necessary to wait for an imaging operation by the imaging unit 210 until vibration of a driving unit (not shown) is stabilized. Causes a problem that the time required for imaging becomes long.
The drive control unit 160a included in the observation apparatus 1a can switch the direction of the diffracted light without stopping the rotation of the diffraction grating 112 and the transmission member 141, so that the degree of vibration generated in the diffraction grating 112 can be reduced. Can do. Therefore, according to the observation apparatus 1a, the time for generating the super-resolution image by eliminating the waiting time until the vibration of the diffraction grating 112 is stabilized while maintaining the resolution of the super-resolution image at a desired resolution. Can be shortened.
Further, as described above, the diffraction grating 112 and the transmission member 141 are continuously rotated without stopping. Therefore, according to this observation apparatus 1a, there is no time for stopping or accelerating, which occurs when the diffraction grating 112 and the transmission member 141 are stopped and rotated intermittently. The time for generating an image can be shortened.

Further, the drive control unit 160a drives the diffraction grating 112 and the transmission member 141 to rotate by changing the rotation speed of the transmission member 141. As described above, the drive control unit 160a changes the phase difference of the ± 1st order diffracted light with respect to the interference fringes in each direction while changing the direction of the interference fringe due to the ± 1st order diffracted light in three directions. Change to 3 types of phases. That is, the drive control unit 160a changes the combinations of the interference fringe direction and the phase difference of the diffracted light in nine ways. Here, when the rotation speed of the transmission member 141 is not variable, in order to change the direction of the interference fringes and the phase difference of the diffracted light in these nine ways, at least one of the diffraction grating 112 and the transmission member 141 is used. There is a period during which the rotation of the motor stops. In this case, if the diffraction grating 112 is stopped, the resolution of the super-resolution image is lowered due to the vibration, so that the imaging operation may be waited until the vibration is stabilized. In this case, the imaging time becomes long. Occurs. On the other hand, if the transmitting member 141 is stopped, it takes time to stop and accelerate. The drive control unit 160a of the present embodiment changes the phase difference of the diffracted light and the direction of the interference fringes due to the diffracted light while rotating and rotating the diffraction grating 112 and the transmission member 141 without changing the speed. Can be made. Therefore, according to this observation apparatus 1a, it is possible to shorten the time for generating the super-resolution image.
In this example, the case where only the rotation speed of the transmission member 141 is made variable has been described. However, if the drive control unit 160a makes the rotation speed of at least one of the diffraction grating 112 and the transmission member 141 variable, The effects described above can be achieved.

Also, in so-called live cell imaging for observing live cells, conventionally, it took a long time to generate a super-resolution image, so if the live cells move before generating a super-resolution image, the desired resolution is achieved. A super-resolution image could not be obtained. On the other hand, since the observation apparatus 1a can shorten the time required to generate a super-resolution image, even a living cell that has been fast moving and has not been able to obtain a desired resolution until now has its super-resolution. An image can be generated at a desired resolution.

In the present embodiment, the drive control unit 160a continuously rotates the diffraction grating 112 and the transmission member 141 until the image of the specimen SP necessary for generating a super-resolution image is captured. The transmission member 141 may be intermittently rotated only by continuously rotating only the diffraction grating 112. In this case, the drive controller 160a changes the direction of the interference fringes formed on the sample SP and changes the phase difference of the interference fringes (the phase difference between the + 1st order diffracted light and the −1st order diffracted light). At least one of them may be controlled so as to temporarily stop the transmissive member 141. Even in this case, it is not necessary to wait for the imaging operation by the imaging unit 210 until the vibration of the driving unit (not shown) (vibration of the diffraction grating 112) is stabilized as described above, so that a super-resolution image with a desired resolution can be obtained. The time until generation can be shortened.

[Modification]
Next, a modified example of the lighting device 10a will be described. FIG. 18 is a diagram showing an illumination device 10a according to this modification. The illumination device 10 a includes a light shielding member 158 arranged between the light guide member 102 and the collimator 103 of the light source device 100. As with the diaphragm member 155 described with reference to FIG. 13, the light shielding member 158 is variable in one or both of the shape and size of the region through which light passes.

The drive control unit 160a can control the light shielding member 158 similarly to the diaphragm member 155 of FIG. The drive controller 160a can block the light from the light source 101 by the light blocking member 158 so that the light from the light source 101 does not enter the illumination area LA at the timing when the diffraction grating 112 is arranged at a rotation angle other than desired. That is, the light shielding member 158 can suppress the diffracted light having a diffraction direction other than the desired light from entering the illumination area LA. In addition, the drive control unit 160a prevents the light from the light source 101 from entering the illumination area LA at the timing when the spot light of the diffracted light on the transmission member 141 is arranged across the second area 122 and the first area 121. In addition, this light can be blocked by the light blocking member 158. That is, the light shielding member 158 can suppress the diffracted light having a phase difference other than that desired from being incident on the illumination area LA.

As shown in FIG. 18, when the light shielding member 158 is arranged at a position where the size of the spot light of the light from the light source 101 is smaller than the size of the spot light on the conjugate plane OS2, for example, the light shielding member 158 can be reduced in size. . The light shielding member 158 may be disposed at any position in the optical path between the light source 101 and the light receiving surface of the imaging unit 210. For example, the drive control unit 160a may prevent the imaging unit 210 from detecting light from the specimen SP that is illuminated at a timing when one or both of the phase difference and the diffraction direction of the diffracted light are in a state other than desired. The shutter 210 may be controlled.

FIG. 19 is a diagram illustrating a modified example of the light beam generation unit 110. The beam bundle generator 110 includes a base member 114 and a plurality of diffraction gratings 112 attached to the base member 114. The base member 114 is rotatable around the rotation axis AX6. The plurality of diffraction gratings 113 are arranged so as to surround the rotation axis AX6. Each of the plurality of diffraction gratings 113 has a circular shape when viewed from the direction of the rotation axis AX6 of the base member 114. The rotation axis AX6 is arranged non-coaxially with the optical axis AX1.

The plurality of diffraction gratings 113 include a first diffraction grating 113a, a second diffraction grating 113b, and a third diffraction grating 113c. The first diffraction grating 113a, the second diffraction grating 113b, and the third diffraction grating 113c are arranged at a pitch of about 120 ° in the circumferential direction around the rotation axis AX6. The diffraction direction of the first diffraction grating 113a, the diffraction direction of the second diffraction grating 113b, and the diffraction direction of the third diffraction grating 113c are set to different directions on the plane orthogonal to the rotation axis AX6. Here, the diffraction direction of the first diffraction grating 113a forms an angle of about 120 ° with the diffraction direction of the second diffraction grating 113b. Further, the diffraction direction of the third diffraction grating 113c forms an angle of about 120 ° with the second diffraction grating 113b in the direction opposite to the direction of the diffraction direction of the first diffraction grating 113a with respect to the diffraction direction of the second diffraction grating 113b. ing.

The first diffraction grating 113a is rotatable on the base member 114 around the center of the first diffraction grating 113a viewed from the direction of the rotation axis AX6 of the base member 114. Similarly to the first diffraction grating 113a, the second diffraction grating 113b and the third diffraction grating 113c can rotate on the base member 114.

In FIG. 19, the first diffraction grating 113 a, the second diffraction grating 113 b, and the third diffraction grating 113 c are all connected to one gear 115. The first diffraction grating 113a, the second diffraction grating 113b, and the third diffraction grating 113c rotate in conjunction with each other as the gear 115 rotates. The gear 115 rotates in parallel with the base member 114.
Here, the exposure area PE shown in FIG. 19 is an area through which light emitted from the collimator 103 is transmitted. The position of the exposure region PE does not change even when the base member 114 rotates. Accordingly, when the first diffraction grating 113a, the second diffraction grating 113b, and the third diffraction grating 113c rotate around the rotation axis AX6 as the base member 114 rotates, each diffraction grating sequentially passes through the exposure region PE. To do.

Here, it is assumed that the gear 115 does not rotate. In this case, the first diffraction grating 113a rotates around the rotation axis AX6 as the base member 114 rotates, and the diffraction direction changes. The rotation speed of the gear 115 is set according to the rotation speed of the base member 114 so as to cancel the change in the diffraction direction of the first diffraction grating 113a due to the rotation around the rotation axis AX6 of the base member 114. Therefore, the diffraction direction of the first diffraction grating 113a does not change even when the base member 114 and the gear 115 rotate. Further, as in the first diffraction grating 113a, the diffraction directions of the second diffraction grating 113b and the third diffraction grating 113c do not change even when the base member 114 and the gear 115 rotate.
As described above, when the diffraction grating 112 having a periodic structure in one direction is continuously rotated, the diffraction direction changes according to the rotation of the diffraction grating 112. For this reason, when the diffraction grating 112 is continuously rotated, if the exposure time of the imaging unit 210 is increased, the contrast of the interference fringes formed on the specimen SP may be reduced, and the resolution of the super-resolution image may be reduced. There is sex. On the other hand, according to the plurality of diffraction gratings 113 according to this modification, even if the diffraction gratings 113 are continuously rotated, the diffraction direction is maintained in a constant direction while each diffraction grating 113 passes through the exposure region PE. Can do. Therefore, according to the plurality of diffraction gratings 113 according to this modification, a super-resolution image with a desired resolution can be obtained even if the exposure time of the imaging unit 210 is increased.
In addition, the drive control unit 160a of the present embodiment rotationally drives the diffraction grating 113 without stopping it. Therefore, according to this observation apparatus 1a, the standby time until the vibration of the diffraction grating 113 is stabilized can be eliminated, so that the time for generating a super-resolution image can be shortened.

Next, a modified example of the phase applying unit 120 will be described. 20 (a) to 20 (c) are diagrams showing modifications of the phase applying unit 120, respectively.

In the phase imparting unit 120 shown in FIG. 20A, a member having a property of transmitting light is disposed in the second region 122, and the first region 121 is a vacuum region or a gas region. Thus, no member may be disposed in one of the second region 122 and the first region 121. For example, the second region 122 is a vacuum region or a gas region, and light is transmitted to the first region 121. A member having the property of transmitting may be arranged. The first area 121 may be a liquid area such as water or oil.

20B is different from the configuration of FIG. 5C in the magnitude relationship between the optical distance of the second region 122 and the optical distance of the first region 121 of the transmission member 141. In this modification, the refractive index of the second region 122 is smaller than the refractive index of the first region 121, and the optical distance in the second region 122 is smaller than the optical distance in the first region 121. As a result, the transmissive member 141 adjusts the phase difference between the light flux that passes through the second region 122 and the light flux that passes through the first region 121 so that the phase of the light flux that passes through the second region 122 advances. As described above, the phase applying unit 120 may advance or relatively delay the phase of the light beam transmitted through the second region 122 with respect to the phase of the light beam transmitted through the first region 121.

20C is different from the configuration of FIG. 5C in the shape of the second region 122 of the transmission member 141. In this modification, the shape of the second region 122 viewed from the direction of the optical axis AX1 of the illumination optical system 150 is a circular shape. As described above, the shape of the second region 122 and the shape of the first region 121 can be set to arbitrary shapes.

Next, a modification of the observation apparatus 1a will be described. FIG. 21 is a diagram showing an observation apparatus 1a according to this modification. The observation apparatus 1a of this modification is different from the configuration of FIG. 13 in the light beam generation unit 110. In the observation apparatus 1a, the light beam generation unit 110 includes an optical path rotating member 159. The optical path rotating member 159 is disposed in the optical path between the diffraction grating 112 and the transmission member 141. In this observation apparatus 1a, the optical path of the diffracted light diffracted by the diffraction grating 112 is rotated around the optical axis AX1 of the illumination optical system 150 by the optical path rotating member 159 instead of rotating the diffraction grating 112.

FIG. 22 is a view showing an optical path rotating member 159 according to this modification. The optical path rotating member 159 is an optical member called a dove prism or an image rotating prism. The optical path rotating member 159 includes an incident side end surface STI on which light from the diffraction grating 112 is incident, an inner surface SI on which light incident from the incident side end surface STI is reflected, and light reflected on the inner surface SI to the outside of the optical path rotating member 159. And an exit-side end face STO that exits. The incident-side end surface STI is inclined with respect to the optical axis AX1 of the illumination optical system 150. The exit-side end surface STO is inclined with respect to the optical axis AX1 symmetrically with respect to the incident-side end surface STI with respect to a plane perpendicular to the optical axis AX1 of the illumination optical system 150. The cross-sectional shape of the optical path rotating member 159 in a plane perpendicular to these three planes is an isosceles trapezoid. In this isosceles trapezoid, one of the two oblique sides corresponds to the incident side end surface STI, the other of the two oblique sides corresponds to the emission side end surface STO, and the bottom corresponds to the inner surface SI.

The diffracted light that has entered the incident side end surface STI from the diffraction grating 112 is refracted by the incident side end surface STI and is incident on the inner surface SI. In this embodiment, the diffracted light from the incident side end surface STI is reflected by the inner surface SI by satisfying the total reflection condition at the inner surface SI. The diffracted light reflected by the inner surface SI enters the emission-side end surface STO, is refracted by the emission-side end surface STO, and is emitted to the outside of the optical path rotating member 159.

The optical path rotating member 159 can rotate around the rotation axis AX7. The rotation axis AX7 is disposed on a line connecting the center of the incident side end face STI and the center of the emission side end face STO. The rotation axis AX7 is coaxial with the optical axis AX1 of the illumination optical system 150. The optical path rotating member 159 is rotated by torque supplied from the driving unit. This drive unit is controlled by the drive control unit 160a shown in FIG. 21 to rotate the optical path rotating member 159. The drive control unit 160a can control the rotation angle of the optical path rotation member 159 by controlling the drive unit.

Between the diffraction grating 112 and the optical path rotating member 159, the optical path of the + 1st order diffracted light L1-1 and the optical path of the −1st order diffracted light L1-2 are point symmetric with respect to the rotation axis AX7. In FIG. 22, the inner surface SI of the optical path rotating member 159 is perpendicular to the plane including the + 1st order diffracted light L1-1 and the −1st order diffracted light L1-2. Such a rotation angle of the optical path rotation member 159 is appropriately referred to as a reference angle. When the optical path rotating member 159 is at the reference angle, the optical path of the + 1st order diffracted light L1-1 and the optical path of the −1st order diffracted light L1-2 between the transmission member 141 and the optical path rotating member 159 shown in FIG. Compared with the optical path between the diffraction grating 112 and the optical path rotating member 159, the positional relationship is reversed with respect to a plane passing through the rotation axis AX7 and parallel to the inner surface SI. When the optical path rotating member 159 is rotated around the rotation axis AX7, the optical path of the + 1st order diffracted light L1-1 and the optical path of the −1st order diffracted light L1-2 between the diffraction grating 112 and the optical path rotating member 159 are rotated. It rotates about the rotation axis AX7 while maintaining a point-symmetrical positional relationship with respect to AX7. As a result, the spot light of the + 1st order diffracted light L1-1 and the spot light of the −1st order diffracted light L1-2 formed in the transmitting member 141 shown in FIG. 21 are point-symmetric with respect to the optical axis AX1 of the illumination optical system 150. It rotates around the optical axis AX1 while maintaining the positional relationship. The drive controller 160a controls the rotation angle of the optical path rotating member 159, thereby controlling the position of the spot light of the + 1st order diffracted light L1-1 and the spot light of the −1st order diffracted light L1-2 formed on the transmission member 141. You can control the position.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. In addition, about the structure and operation | movement similar to each embodiment mentioned above, description is simplified or abbreviate | omitted.
FIG. 23 is a diagram showing an observation apparatus 1b according to the third embodiment. The observation apparatus 1b of the present embodiment is different from the above-described embodiments in that the specimen SP is illuminated with a three-beam interference fringe generated using zero-order diffracted light in addition to ± first-order diffracted light.

When these three light beams are caused to interfere, on the specimen SP, there are interference fringes (interference fringes A) by two light beams of ± 1st order diffracted light, 0th order diffracted light and 1st order diffracted light, 0th order diffracted light and −1st order diffracted light, An interference fringe (interference fringe B) having a period twice that of the interference fringe A is formed and present. Of these, the interference caused by the 0th-order diffracted light and the 1st-order diffracted light, and the 0th-order diffracted light and the -1 diffracted light order are not symmetrical with respect to the optical axis. As a result, the combined wave of these diffracted lights becomes interference fringes having a structure not only in the direction perpendicular to the optical axis but also in the optical axis direction on the specimen SP.

The specimen structured and illuminated with the three-beam interference fringes is modulated in the optical axis direction in addition to the modulation in the direction perpendicular to the same optical axis as the embodiment structured and illuminated with the two-beam interference fringes. Therefore, when a modulated image is acquired and an appropriate image calculation is performed, a so-called sectioning image with improved resolution in the optical axis direction can be obtained.

MGLGustafsson, DAAgard, JWSedat, “Doubling the lateral resolution of wide-field fluorescence microscopy using structured illumination”, Proceedings of the SPIE-The International Society for Optical Engineering (2000) vol.3919, vol.3919 50. (Non-Patent Document 2).

There are five unknowns in the image restoration calculation of structured illumination by three-beam interference. Among the components that the spatial frequency information of the sample is diffracted by the structured illumination, those included in the modulated image are the zero-order component and the ± first-order component in the fZ = 0 plane of the wave number space, Although there are seven components of the four components in the fZ ≠ 0 plane of the wave number space, the structure of the sample in the optical axis direction is investigated by the specimen z-feeding (movement in the optical axis direction), etc. This is because it is not necessary to separate two pairs in which only the sign of fz is different among the components in the fZ ≠ 0 plane in the wave number space. Therefore, it is necessary to acquire at least five types of phase modulation images having different phase differences between diffracted lights in each direction of the interference fringes. This observation apparatus 1b acquires five types of phase-modulated images in each of the three directions of the interference fringes described above and a total of 15 phase-modulated images. The configuration of the observation apparatus 1b will be described.

The observation device 1b includes an illumination device 10b and a drive control unit 160b.
The illuminating device 10 b includes a diffraction grating 111 as the light beam generation unit 110. This diffraction grating 111 is a three-way diffraction grating, like the diffraction grating 111 provided in the observation apparatus 1 described above. The diffraction grating 111 has a fixed relative position to the illumination optical system 150 and is provided so as not to rotate.
The illumination device 10 b includes a shutter member 132 as the light beam generation unit 110 and a transmission member 144 as the phase applying unit 120. An example of the configuration of the shutter member 132 and the transmission member 144 will be described with reference to FIG.

FIG. 24 is a plan view of the shutter member 132 and the transmission member 144 according to the present embodiment as viewed from the direction of the optical axis AX1. As shown in FIG. 23, the shutter member 132 is arranged in the optical path between the diffraction grating 111 and the illumination area LA with the rotation axis AX3 of the shutter member 132 and the optical axis AX1 of the illumination optical system 150 being coaxial. ing. The shutter member 132 can rotate around the rotation axis AX3, and rotates around the rotation axis AX3 by torque supplied from a driving unit (not shown) such as an electric motor. This drive unit is controlled by the drive control unit 160b to rotate the shutter member 132. The drive control unit 160b can control the rotation angle of the shutter member 132 by controlling the drive unit.

Further, as shown in FIG. 24A, the shutter member 132 is the same as the shutter member 131 described above in that it has a passage portion AT through which light can pass and a light shielding portion AS that blocks light. The shutter member 132 is different from the shutter member 131 described above in that the shutter member 132 includes a third passage portion ATc in addition to the first passage portion ATa and the second passage portion ATb. The third passage portion ATc is a circular opening around the rotation axis AX3 with the rotation axis AX3 as the center. The shutter member 131 described above does not have an opening corresponding to the third passage portion ATc, and shields the 0th-order diffracted light incident from the diffraction grating 111. On the other hand, the shutter member 132 allows the 0th-order diffracted light to pass therethrough without being blocked by the third passage portion ATc. Similarly to the shutter member 131 described above, the shutter member 132 allows ± first-order diffracted light to pass through the first passage portion ATa and the second passage portion ATb. That is, according to the shutter member 132, 0th-order diffracted light can be transmitted in addition to ± 1st-order diffracted light. The first passage portion ATa and the second passage portion ATb are arranged in the order of the light shielding portion, the second passage portion ATb, the light shielding portion, and the first passage portion ATa in the counterclockwise direction from the reference point P on the shutter member 132. The

As shown in FIG. 23, the transmitting member 144 is disposed at the position of the conjugate plane OS1. The transmission member 144 is a plate-like member, the surface on which light from the light source 101 is incident is substantially perpendicular to the optical axis AX1 of the illumination optical system 150, and the rotation axis AX4 of the transmission member 144 and the optical axis. AX1 is arranged coaxially. The transmission member 144 can rotate around the rotation axis AX4, and rotates around the rotation axis AX4 by torque supplied from a drive unit such as an electric motor. This drive unit is controlled by the drive control unit 160b to rotate the transmission member 144. The drive control unit 160b can control the rotation angle of the transmission member 144 by controlling the drive unit.

Further, as shown in FIG. 24B, the transmissive member 144 is similar to the transmissive member 141 described above in that it includes a first region 121 (reference phase region) and a second region 122 (phase modulation region). . In addition, the transmission member 144 is different from the transmission member 141 described above in that the second region 122 includes four regions each having a thickness different from that of the first region 121. The four regions included in the second region 122 are an A region 122a, a B region 122b, a C region 122c, and a D region 122d. In the transmissive member 144, the central angles of the first region 121 and the A region 122a to D region 122d are each 60 °.
The first region 121 and the A region 122a are arranged at rotationally symmetric positions around the rotation axis AX4. Further, the B region 122b and the D region 122d are disposed at rotationally symmetric positions around the rotation axis AX4. Further, the C region 122c includes the periphery of the rotation axis AX4, and the two C regions 122c are arranged at rotationally symmetric positions around the rotation axis AX4. These regions are arranged in the order of C region 122c, B region 122b, A region 122a, C region 122c, D region 122d, and first region 121 in the counterclockwise direction from the reference point Q on the transmission member 144. .

The thicknesses of the A region 122a to the D region 122d are set as follows. That is, the thickness of the A region 122a is set so that the phase difference between the diffracted light transmitted through the first region 121 and the diffracted light transmitted through the A region 122a is equivalent to 16π / 5.
The thickness of the B region 122b is set so that the phase difference between the diffracted light transmitted through the first region 121 and the diffracted light transmitted through the B region 122b is equivalent to 14π / 5.
The thickness of the C region 122c is set so that the phase difference between the diffracted light transmitted through the first region 121 and the diffracted light transmitted through the C region 122c is equivalent to 8π / 5.
The thickness of the D region 122d is set so that the phase difference between the diffracted light transmitted through the first region 121 and the diffracted light transmitted through the D region 122d is equivalent to 2π / 5.

Next, with reference to FIGS. 25 to 27, a description will be given of a procedure in which the drive control unit 160b acquires five types of phase-modulated images for each of the three interference fringe directions.
25 and 26 are schematic diagrams illustrating an example of the positional relationship between the light beam generation unit and the phase providing unit. The drive controller 160b sets the rotation angle of the shutter member 132 and the rotation angle of the transmission member 144 without stopping the shutter member 132 and the transmission member 144, and 18 of patterns 1 to 18 shown in FIG. 25 and FIG. Change the street. In this example, the drive control unit 160b matches the rotation speed of the shutter member 132 with the rotation speed of the transmission member 144, and causes the 0th-order diffracted light and the ± 1st-order diffracted light to pass through the shutter member 132. Thus, the shutter member 132 and the transmission member 144 are continuously driven to rotate. Further, as described above, the 0th-order diffracted light is transmitted through the C region 122 c of the transmission member 144 regardless of the rotation angle of the shutter member 132 and the rotation angle of the transmission member 144. Hereinafter, description of the 0th-order diffracted light passing through the C region 122c of the transmissive member 144 is omitted.

First, patterns 1 to 3 in FIG. 25 will be described. The drive controller 160b sets the shutter member 132 to a rotation angle of 0 ° and the transmission member 144 to a rotation angle of 0 ° (Pattern 1: Time T10 to Time T10 ′ in FIG. 27). In this pattern 1, ± 1st-order diffracted light in the first direction D1 passes through the shutter member 132. The + 1st order diffracted light passes through the first region 121 (region A1 where the spot is formed on the conjugate plane OS1) of the transmission member 144. Further, the −1st order diffracted light passes through the A region 122a (region A2 where the spot is formed on the conjugate plane OS1) of the transmitting member 144. Hereinafter, the position of the reference point P of the shutter member 132 in the pattern 1 is referred to as the origin position of the shutter member 132. Further, the position of the reference point Q of the transmission member 144 in the pattern 1 is referred to as the origin position of the transmission member 144.

Next, the drive control unit 160b rotates the reference point P 60 degrees counterclockwise from the origin position with respect to the shutter member 132 to a rotation angle 60 °, and the transmission member 144 sets the reference point Q counterclockwise from the origin position. The rotation angle is 80 ° (pattern 2: time T11 to time T11 ′ in FIG. 27). In the pattern 2, ± 1st order diffracted light in the second direction D2 passes through the shutter member 132. The + 1st order diffracted light is transmitted through the first region 121 (region A3 where a spot is formed on the conjugate plane OS1) of the transmission member 144. Further, the −1st order diffracted light passes through the A region 122a (the region A4 where the spot is formed on the conjugate plane OS1) of the transmitting member 144.

Next, the drive control unit 160b rotates the reference point P by 120 ° counterclockwise from the origin position for the shutter member 132 at a rotation angle of 120 °, and the transmission member 144 sets the reference point Q counterclockwise from the origin position. The rotation angle is 160 ° rotated by 160 ° (Pattern 3: Time T12 to Time T12 ′ in FIG. 27). In the pattern 3, ± 1st-order diffracted light in the third direction D3 passes through the shutter member 132. The + 1st order diffracted light is transmitted through the first region 121 (region A5 where a spot is formed on the conjugate plane OS1) of the transmission member 144. Further, the −1st order diffracted light passes through the A region 122a (the region A6 where the spot is formed on the conjugate plane OS1) of the transmitting member 144.

As described above, in the patterns 1 to 3, the drive control unit 160b transmits the + 1st order diffracted light in the first direction D1 to the third direction D3 through the first region 121 and the −1st order diffracted light through the A region 122a. Further, the shutter member 132 and the transmission member 144 are driven to rotate. As a result, in the patterns 1 to 3, the phase difference of the ± first-order diffracted light becomes −16π / 5 (that is, 4π / 5). The phase difference between the + 1st order diffracted light and the 0th order diffracted light is −8π / 5 (ie, 2π / 5). The phase difference between the −1st order diffracted light and the 0th order diffracted light is −8π / 5 (ie, 2π / 5). That is, in the patterns 1 to 3, the drive control unit 160b changes the direction of the interference fringes in three ways without changing the phase difference of each diffracted light.

Next, patterns 4 to 6 in FIG. 25 will be described. The drive control unit 160b rotates the reference point P 180 degrees counterclockwise from the origin position for the shutter member 132 and rotates the reference point Q 240 degrees counterclockwise from the origin position for the transmission member 144. The rotation angle is set to 240 ° (pattern 4: time T13 to time T13 ′ in FIG. 27). In the pattern 4, ± 1st order diffracted light diffracted by the periodic structure in the first direction D1 passes through the shutter member 132. The + 1st order diffracted light passes through the D region 122a of the transmissive member 144. Further, the −1st order diffracted light passes through the B region 122b of the transmission member 144. For this reason, in the pattern 4, the phase difference of the ± first-order diffracted light is −12π / 5 (that is, 8π / 5). In addition, the phase difference between the + 1st order diffracted light and the 0th order diffracted light is −6π / 5 (that is, 4π / 5). The phase difference between the −1st order diffracted light and the 0th order diffracted light is −6π / 5 (ie, 4π / 5).

In the patterns 5 to 6, in the second direction D2 and the third direction D3 as well as the pattern 4, the + 1st order diffracted light is transmitted through the D region 122a of the transmission member 144, and the −1st order diffracted light is transmitted through the B of the transmission member 144. The region 122b is transmitted. In this way, in the patterns 4 to 6, the drive control unit 160b has the + 1st order diffracted light diffracted by the periodic structure in the first direction D1 to the third direction D3 in the D region 122a, the −1st order diffracted light in the B region 122b, The shutter member 132 and the transmissive member 144 are rotationally driven so as to transmit each. That is, in the patterns 4 to 6, the drive control unit 160b changes the direction of the interference fringes in three ways without changing the phase difference of each diffracted light.

Hereinafter, since the patterns 7 to 15 are the same as described above, the description thereof is omitted. Note that in the patterns 16 to 18 shown in FIG. 25, the imaging unit 210 does not capture a phase-modulated image. When the pattern 9 (from time T18 to time T18 ′ in FIG. 27) changes to the pattern 10 (from time T19 to time T19 ′ in FIG. 27), the drive control unit 160b causes the light shielding member (for example, the diaphragm member 155). The shutter member 132 and the transmission member 144 are rotationally driven while shielding the diffracted light. Thereby, interference fringes due to unnecessary diffracted light can be prevented from being formed on the specimen SP (in other words, unnecessary diffracted light can be prevented from entering the imaging unit 210).

In this way, the drive controller 160b can generate 15 different interference fringe states by changing the phase difference of the diffracted light to 5 ways and the direction of the interference fringes to 3 ways. Specifically, the following phase difference can be given to each diffracted light in each direction of the interference fringes.

+ 1st order: -1st order + 1st order: 0th order 0th order: -1st order (patterns 1, 2, 3) 4π / 5 2π / 5 2π / 5
(Pattern 4, 5, 6) 8π / 5 4π / 5 4π / 5
(Pattern 7, 8, 9) 0 0 0
(Patterns 10, 11, and 12) 16π / 5 8π / 5 8π / 5
(Patterns 13, 14, and 15) 12π / 5 6π / 5 6π / 5

As described above, the observation apparatus 1b according to the present embodiment can change the phase difference of the diffracted light in five ways while changing the direction of the interference fringes in three ways when the three light beams interfere with each other. When a modulated image obtained by imaging the interference fringes is acquired and appropriate image calculation is performed, a so-called sectioning image with improved resolution in the optical axis direction is obtained. That is, according to the observation apparatus 1b, the resolving power in the optical axis direction can also be improved.

According to the observation apparatus 1b of the present embodiment, the time until a super-resolution image is generated can be shortened as in the first embodiment described above.

The observation apparatus 1b may rotate the shutter member 131 and the transmission member 144 in the direction opposite to the above-described direction.
Further, this observation apparatus 1b may include a diffraction grating 112 that is a one-way diffraction grating as in the second embodiment described above, instead of the diffraction grating 111 and the shutter member 131. In this case, the diffraction grating 112 is a unidirectional diffraction grating, like the diffraction grating 112 provided in the observation apparatus 1a described above, and rotates by torque supplied from a driving unit (not shown) such as an electric motor. This drive unit is controlled by the drive control unit 160b to rotate the diffraction grating 112. The drive control unit 160 b can control the rotation angle of the diffraction grating 112 by controlling the drive unit of the diffraction grating 112.
In this case, the diffraction grating 112 and the transmission member 144 may be continuously rotated, or only the diffraction grating 112 may be continuously rotated.
Even with this configuration, the observation device 1b of the present embodiment can change the phase difference of the diffracted light in five ways while changing the direction of the interference fringes in three ways when the three light beams interfere with each other. it can.
In this case, similarly to the second embodiment described above, it is possible to shorten the time until a super-resolution image is generated.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and appropriate modifications may be made without departing from the spirit of the present invention. it can. You may combine the structure as described in each embodiment mentioned above.

In FIG. 2 and the like, the diffraction grating 111 is a three-way diffraction grating having three diffraction directions, but may be a two-way diffraction grating having two diffraction directions, or may have many diffraction directions having four or more diffraction directions. It may be a directional diffraction grating. The diffraction grating 111 may be tilted non-perpendicularly with respect to the optical axis AX1 of the illumination optical system 150.

In FIG. 1 and the like, the shutter member 131 (or the shutter member 132; the same in the following description) is disposed in the optical path between the projection lens 151 and the conjugate plane OS1, but the diffraction grating 111 and the illumination region Between LA, the optical paths of a plurality of light beams diffracted by the diffraction grating 111 may be arranged at any position where they do not overlap each other. For example, the shutter member 131 may be disposed in the optical path between the conjugate plane OS1 and the relay lens 152, may be disposed between the diffraction grating 111 and the projection lens 151, or may be the objective lens 154. In FIG. 2, the optical axis may be disposed at or near the position of a plane optically conjugate with the conjugate plane OS1. However, the spot size of each diffracted light is minimized at the position of the conjugate plane OS1 in the optical path between the projection lens 151 and the relay lens 152, and the interval between the spots of the diffracted light is between the projection lens 151 and the relay lens 152. In this optical path, the maximum is obtained at the position of the conjugate plane OS1. Therefore, the closer the shutter member 131 is to the conjugate plane OS1 in the direction of the optical axis AX1 of the illumination optical system 150, the easier it is for the light beam to be selected by the shutter member 131.

The shutter member 131 does not have to be disk-shaped, and for example, the outer shape of the illumination optical system 150 viewed from the direction of the optical axis AX1 is triangular, rectangular, other polygons, ellipse, straight line, or free curve. Or any of the shapes enclosed by both sides may be sufficient. The shutter member 131 may not be plate-shaped, and may be block-shaped, for example. The rotation axis of the shutter member 131 may be inclined with respect to the optical axis AX1 with respect to the optical axis AX1 of the illumination optical system 150.

In FIG. 5 and the like, the transmissive member 141 (or the transmissive member 144; the same in the following description) is plate-shaped, but may be block-shaped. The transmissive member 141 may be disposed at any position where the optical paths of the plurality of diffracted lights emitted from the diffraction grating 111 do not overlap with each other in the optical path between the diffraction grating 111 and the illumination area LA. In FIG. 5 and the like, each of the second region 122 and the first region 121 is one, but one or both of the second region 122 and the first region 121 are at different positions in the circumferential direction around the rotation axis AX4. A plurality of arranged regions may be included. The number of regions having different optical distances in the transmissive member 141 is two, but may be three or more.
Further, in FIG. 5 and the like, the transmission member 141 has been described as being disposed at the position of the conjugate plane OS1, but the present invention is not limited to this. The transmission member 141 may be disposed at a position where the + 1st order diffracted light and the −1st order diffracted light are incident on different positions on the transmission member 141, for example, between the projection lens 151 and the relay lens 152. It suffices to be arranged at the position of

It should be noted that the transmission member 141 may be provided with a center-of-gravity adjustment unit so that the center of gravity of the transmission member 141 is disposed on the rotation axis AX4. This center-of-gravity adjustment unit may be, for example, a film provided at a position where diffracted light from the diffraction grating 111 is not incident. Further, the shape of the transmission member 141 may be adjusted so that the center of gravity of the transmission member 141 is disposed on the rotation axis AX4, and a notch, a hole, or the like may be formed for adjusting the center of gravity.

In addition, about the structure of the light source device 100, it can change suitably. In the above-described embodiment, the light source device 100 is a part of the illumination devices 10, 10a, and 10b. However, at least a part of the light source device 100 may be an external device of the illumination devices 10, 10a, and 10b. The light source 101 is not limited to a laser diode, and can be various light emitting elements such as a semiconductor laser, a solid-state laser, and a gas laser.

Note that the light blocking member that prevents the formation of interference fringes due to unnecessary diffracted light on the specimen SP may not be the diaphragm member 155, for example, a laser shutter (not shown) provided in the light source device 100. In addition, various members can be used for light shielding. Moreover, it may not be a light shielding member, for example, you may stop the laser generation of the light source device 100 temporarily.

In addition, although each lens is drawn by one member in FIG. 1 etc., the number of lens members which each lens has may be one, and may be two or more. The illumination optical system 150 may include a cut lens obtained by cutting a part of a rotationally symmetric lens member, or may include a rotationally asymmetric free-form surface lens.

In FIG. 1 and the like, the illumination optical system 150 is a refractive optical system that does not include a reflective member having power, but a catadioptric optical system that includes both a lens member having power and a reflective member having power. It may be. Further, the illumination optical system 150 may be a reflective optical system that includes a reflective member having power and does not include a lens member having power. The reflecting member having power is, for example, a concave mirror or a convex mirror.

The illumination optical system 150 may include one or both of a reflecting member having no power and a transmitting member having no power in any of the refractive system, the catadioptric system, and the reflecting system. Good.

In addition, an example has been described in which the drive control units 160 and 160b switch between the rotation operation and the stop operation of the transmission member 141 while continuously rotating the shutter member 131 between the timings T3 ′ to T7. Not limited to this. For example, the drive control units 160 and 160b rotate the shutter member 131 continuously between timings T3 ′ to T7, and set the rotation speed of the transmission member 141 to a rotation speed slower than the rotation speed of the shutter member 131. The transmission member 141 may be controlled to be continuously rotated. More specifically, the drive control units 160 and 160b change the rotation speed of the transmission member 141 to 1/3 of the rotation speed of the shutter member 131 between the timings T3 ′ to T7, and sets the transmission member 141. You may control so that it may rotate continuously.

In the above description, the configuration in which the drive control units 160 and 160b control the shutter member 131 and the transmission member 141 in accordance with the exposure timing controlled by the imaging control unit 212 has been described, but the present invention is not limited thereto. For example, the drive control units 160 and 160b may be configured to control the exposure timing of the imaging unit 210.

In addition, each part with which each control part (The drive control part 160, 160a, 160b, the imaging control part 212, the calculating part 220) with which observation apparatus 1, 1a, 1b of each embodiment mentioned above is provided is implement | achieved by dedicated hardware. Or may be realized by a memory and a microprocessor.

In addition, although the drive control parts 160, 160a, and 160b of each above-mentioned embodiment are provided in the illuminating devices 10, 10a, and 10b, they do not need to be provided in the illuminating devices 10, 10a, and 10b. For example, as long as it is inside the observation device 1, 1a, 1b, it may be outside the illumination device 10, 10a, 10b, or inside an arithmetic unit (not shown) outside the observation device 1, 1a, 1b. There may be. Similarly, the calculation unit 220 may also be inside a calculation device (not shown) outside the observation devices 1, 1a, 1b. Further, the drive control units 160, 160a, 160b and the calculation unit 220 may be inside a common calculation device (not shown) outside the observation devices 1, 1a, 1b.

In addition, each control part with which the observation apparatus 1, 1a, 1b is comprised is comprised with memory and CPU (central processing unit), and the program for implement | achieving the function of each part with which a display apparatus is provided is loaded to memory, and is performed. The function may be realized by.

Also, a program for realizing the functions of the control units included in the observation apparatuses 1, 1a, and 1b is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed. By doing so, you may perform the process by each part with which a control part is provided. Here, the “computer system” includes an OS and hardware such as peripheral devices.

Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM or a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory in a computer system serving as a server or a client in that case, and a program that holds a program for a certain period of time are also included. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

Note that the requirements of the above-described embodiments can be combined as appropriate. Some components may not be used. In addition, as long as it is permitted by law, a part of the description of the text is incorporated with the disclosure of all published publications and US patents related to the illumination device, the observation device, the observation method, etc. cited in the above embodiments and modifications. And

DESCRIPTION OF SYMBOLS 1, 1a, 1b ... Observation apparatus, 10, 10a, 10b ... Illumination device, 101 ... Light source, 110 ... Ray bundle production | generation part, 111 ... Diffraction grating (multi-directional diffraction grating), 112 ... Diffraction grating, 120 ... Phase provision part 121 ... 1st area | region (reference | standard phase area | region), 122 ... 2nd area | region (phase modulation area | region), 150 ... Illumination optical system (interference optical system), 160, 160a, 160b ... Drive control part

Claims (17)

In an illumination device that illuminates a specimen with interference fringes,
A light flux generation unit that generates a first light flux and a second light flux from light emitted from the light source;
A phase imparting section that imparts a phase difference between the first light flux and the second light flux;
An interference optical system that generates interference fringes by causing the first light flux and the second light flux to interfere with each other;
An illumination apparatus comprising: a drive control unit that drives each of the light beam generation unit and the phase providing unit to change at least one of the direction of the interference fringes and the phase difference. The drive control unit
The lighting device according to claim 1, wherein the light flux generation unit and the phase providing unit are driven to change the phase difference when the direction of the interference fringes is a predetermined direction. The drive control unit
The lighting device according to claim 1, wherein the light flux generation unit and the phase providing unit are driven to change the direction of the interference fringes when the phase difference is a predetermined phase difference. The light flux generator is
A multidirectional diffraction grating having a periodic structure in three or more directions different from each other and dividing an incident light beam into a plurality of light beams;
A light bundle selection unit that selects two light bundles among the plurality of light bundles divided by the multidirectional diffraction grating as the first light bundle and the second light bundle;
The drive control unit
The light beam selecting unit and the phase providing unit are respectively driven so that at least one of the first light beam or the second light beam is incident on the phase applying unit and on the phase applying unit to be incident The lighting device according to claim 3, wherein the direction of the interference fringes is changed when the phase difference is a predetermined phase difference by changing a position. The light flux generator is
A beam bundle splitting unit that has a periodic structure in one direction and divides an incident beam bundle into a plurality of beam bundles including the first beam bundle and the second beam bundle;
The drive control unit
Driving the light beam splitting unit and the phase applying unit to cause at least one of the first light beam bundle or the second light beam to enter the phase applying unit, and the position on the phase applying unit to be incident 5. The illumination device according to claim 3, wherein the direction of the interference fringes is changed when the phase difference is a predetermined phase difference. The phase applying unit is
A reference phase region through which the incident light bundle passes,
A phase modulation region that converts an incident light beam into a light beam having a phase different from the phase of the light beam that has passed through the reference phase region;
The drive control unit
Driving the light beam generation unit and the phase providing unit to cause one light beam of the first light beam and the second light beam to be incident on the reference phase region, and the other light beam to By changing the incident position in the reference phase area and the incident position in the phase modulation area while entering the phase modulation area, the interference occurs when the phase difference has a predetermined phase difference. The illumination device according to any one of claims 3 to 5, wherein a direction of the stripe is changed. The drive control unit
By rotating the light beam generation unit about the optical axis of the interference optical system as a rotation center, the optical path between the first light beam and the second light beam is changed along the optical axis to change the optical path. The direction of an interference fringe is controlled. The illuminating device as described in any one of Claims 1-6 characterized by the above-mentioned. The light flux generation unit generates a third light flux from light emitted from a light source,
The phase imparting unit imparts a phase difference to each of the first light flux and the second light flux, the second light flux and the third light flux, and the third light flux and the first light flux. ,
4. The interference optical system generates interference fringes by causing the first light bundle, the second light bundle, and the third light bundle to interfere with each other. 5. The lighting device described in 1. A light shielding unit that shields at least a part of the light bundles generated by the light bundle generation unit while the direction of the interference fringes and the phase difference are changed by the drive control unit. The lighting device according to any one of claims 1 to 8, wherein the lighting device is characterized. A polarization unit that converts the polarization state of the light beam generated by the light beam generation unit into linearly polarized light,
The interference optical system is
10. The interference fringe is generated by making the light beam that has been linearly polarized by the polarization unit into S-polarized light with respect to the sample in the vicinity of the sample. The lighting device described in 1. The phase applying unit is
It is arrange | positioned in the conjugate surface formed by condensing of diffracted light. The illuminating device as described in any one of Claims 1-10 characterized by the above-mentioned. In an illumination device that illuminates a specimen with interference fringes,
A light flux generation unit that generates a first light flux and a second light flux from light emitted from the light source;
A phase imparting section that imparts a phase difference between the first light flux and the second light flux;
An interference optical system that generates interference fringes by causing the first light flux and the second light flux to interfere with each other;
A drive control unit that continuously drives the light beam generation unit and intermittently drives the phase providing unit to change at least one of the direction of the interference fringes and the phase difference. A lighting device. The drive control unit
The phase difference is changed when the direction of the interference fringes is a predetermined direction by continuously driving the light beam generation unit and driving the phase applying unit intermittently. 12. The lighting device according to 12. The drive control unit
The beam bundle generating unit is continuously driven, and the phase applying unit is intermittently driven to change the direction of the interference fringes when the phase difference is a predetermined phase difference. The lighting device according to claim 12. The light flux generator is
A beam bundle splitting unit that has a periodic structure in one direction and divides an incident beam bundle into a plurality of beam bundles including the first beam bundle and the second beam bundle;
The drive control unit
Continuously driving the light beam generating unit, driving the phase applying unit intermittently, and causing at least one of the first light beam or the second light beam to enter the phase applying unit; and The direction of the interference fringes is changed when the phase difference is a predetermined phase difference by changing a position on the phase applying unit to be incident. 15. The lighting device according to claim 1. The lighting device according to any one of claims 1 to 15,
An imaging optical system that forms an image of the specimen illuminated by the interference fringe by the illumination device;
An imaging unit that captures an image of the specimen imaged by the imaging optical system;
An observation device comprising: a calculation unit that generates an image of the specimen based on the image captured by the imaging unit. The illumination device according to any one of claims 1 to 15 illuminates a specimen with interference fringes;
Capturing an image of the specimen imaged by an imaging optical system that forms an image of the specimen illuminated by the illumination;
An observation method comprising: a calculation procedure for generating an image of the sample based on the image of the sample imaged by the imaging.

Images