JP2012202777A - Observation device and observation method - Google Patents

Abstract

An object of the present invention is to realize observation capable of suitable detection according to an object to be observed.
A first branching means 3 for branching incident light into first reference light and first measurement light, and first illumination for obliquely illuminating the first measurement light on an object to be observed. An illumination optical system, first combining means 4 for combining the transmitted light from the observation object illuminated obliquely and the first reference light, and the first reference light and the transmitted light from the observation object A transmission type observation device provided with a first detection means 16 for detecting the first interference light, and a second branching means 4 for branching the incident light into a second reference light and a second measurement light; The second illumination optical system for illuminating the object to be observed with the second measurement light, the second combining means 4 for combining the second reference light and the reflected light from the object to be observed, and the second reference And a reflection type observation device including second detection means for detecting second interference light between the light and the reflected light from the object to be observed.
[Selection] Figure 5

Description

  The present invention relates to an observation apparatus and an observation method.

  One of the non-destructive tomographic techniques is optical coherence tomography (OCT) (see Non-Patent Document 1, etc.). OCT can measure the refractive index distribution, spectral information, polarization information, and the like of an object to be observed by using light having a wide wavelength range as a probe. In addition, it is possible to observe the three-dimensional structure of the object to be observed without staining or noninvasively. Therefore, OCT is suitable for in vivo cells.

E.A. Swanson, J.A. Izatt, M.R. Michael, D. Huang, C.P. Lin, J.S. Shuman, C.A. Puliafito, J.G. Fujimoto, 18 (21) 1864-1866, Optics Letters (1993)

  On the other hand, there is also a demand for observing the three-dimensional structure of an object to be observed using OCT in a cultured cell, an intracellular organ, or the like, without staining or noninvasively. However, the above-mentioned observed objects such as cultured cells and intracellular organs vary in size and shape, and depending on the resolution and characteristics of the OCT apparatus, it is often impossible to detect a three-dimensional structure uniformly. .

  The present invention has been made in view of the above problems, and an object thereof is to provide an observation apparatus and an observation method capable of suitable detection according to an object to be observed.

  In one aspect of the observation apparatus of the present invention, a first branching unit that splits incident light into first reference light and first measurement light, and the first measurement light obliquely with respect to the object to be observed. A first illumination optical system for illuminating incident light; a first observation optical system for observing transmitted light from the observation object illuminated obliquely; and the first reference based on the first measurement light. A first reference optical system for forming light, first combining means for combining the first reference light and the transmitted light from the object to be observed, and the first reference light and the object to be observed. First detection means for detecting first interference light with the transmitted light, and first position information acquisition means for acquiring position information of the object along the optical axis direction of the observation optical system. A transmission-type observation device provided; a second branching unit that branches incident light into second reference light and second measurement light; and A second illumination optical system that illuminates the second measurement light, a second observation optical system that observes the reflected light from the illuminated object to be observed, and the second measurement light based on the second measurement light. A second reference optical system for forming the reference light, second combining means for combining the second reference light and the reflected light from the object to be observed, the second reference light and the object to be observed Second detection means for detecting second interference light with reflected light from the object, and second position information acquisition means for acquiring position information of the observation object along the optical axis direction of the observation optical system A reflection type observation device.

  Note that switching means for switching between the transmission type observation device and the reflection type observation device may be provided.

  Further, the first detection means and the second detection means may be the same.

  The first illumination optical system may include an oblique incident means for obliquely incident on the object to be observed.

  The first measurement light in a direction orthogonal to at least one optical axis of the first illumination optical system, the second illumination optical system, the first observation optical system, and the second observation optical system. Alternatively, a scanning unit that scans the second measurement light may be provided.

  In addition, at least one of the first detection unit or the second detection unit may be a spectrum detector that spectrally detects the first interference light or the second interference light.

  Further, in order to make light of a predetermined polarization incident on the half-wave plate or the quarter-wave plate disposed in the first reference light or the first measurement light and the first branching unit. A first polarizing element, a second polarizing element that transmits a part of the first interference light including a polarization direction that is determined based on the predetermined polarized light, and polarized light that is transmitted by the first polarizing element You may provide the 1st control means which changes simultaneously the direction and the polarization direction which the said 2nd polarizing element permeate | transmits.

  In order to make light of a predetermined polarization incident on the half-wave plate or quarter-wave plate arranged in the second reference light or the second measurement light, and the second branching unit. A third polarizing element, a fourth polarizing element that transmits part of the second interference light including a polarization direction that is determined based on the predetermined polarization, and polarized light that is transmitted by the third polarizing element. You may provide the 2nd control means to change simultaneously the direction and the polarization direction which the said 4th polarizing element permeate | transmits.

  Further, the second polarizing element and the fourth polarizing element may be at the same position.

  According to one aspect of the observation method of the present invention, incident light is branched into first reference light and first measurement light, and the first measurement light is obliquely incident on the object to be observed, so that the oblique incidence is performed. The transmitted light from the illuminated object to be observed is observed to form the first reference light based on the first measurement light, and the first reference light and the transmitted light from the object to be observed And a transmission type observation method for acquiring positional information of the object to be observed along the optical axis direction of the observation optical system, and incident light as a second reference light and a second reference light. Branching into measurement light, illuminating the object to be observed with the second measurement light, observing reflected light from the illuminated object to be observed, and using the second measurement light as a reference Interference light obtained by combining the second reference light and the reflected light from the object to be detected is detected, and the reference light is aligned along the optical axis direction of the observation optical system. Said and a method reflective observation that acquires position information of the object under observation, and is characterized in that the observation by switching between the reflective observation method and the transmission observation method.

  ADVANTAGE OF THE INVENTION According to this invention, the observation apparatus and observation method which can perform the suitable detection according to the to-be-observed object are realizable.

It is a block diagram of the OCT apparatus of 1st Embodiment. It is a figure explaining the annular zone mask 22 in the OCT apparatus of 1st Embodiment. It is a figure explaining the optical path in the OCT apparatus of a 1st embodiment. It is a figure explaining the aperture 13 in the OCT apparatus of 1st Embodiment. It is a block diagram of the OCT apparatus of 2nd Embodiment. It is a figure for demonstrating the OCT apparatus of 2nd Embodiment.

  The OCT apparatus according to the first embodiment of the present invention will be described below.

  FIG. 1 is a configuration diagram of the OCT apparatus according to the first embodiment. As shown in FIG. 1, the OCT apparatus includes a light source 1, a collimating lens 2, beam splitters 3 and 4, a beam expander 21, total reflection mirrors 7 and 8, an annular mask 22, objective lenses 9 and 10, sample 11, and sample. A stage 12, an aperture 13, a dispersion correction optical member 14, a cylindrical lens 15, a spectrum detector 16, a control device 17, a calculation device 18, and the like are arranged. The control device 17 controls each part of the light source 1, the objective lens 9, the sample stage 12, the spectrum detector 16, and the annular mask 22, and sends the spectrum signal acquired by the spectrum detector 16 to the arithmetic device 18.

  In the sample 11, for example, a cultured cell as an object to be observed is cultured in a container (not shown). In addition, as a container mentioned above, various things, such as a petri dish, a flask, a well plate, a microplate, can be used. In addition, a slide glass can be used instead of the container.

  The sample 11 is installed on the sample stage 12. The sample stage 12 is movable in a plane (xy plane) perpendicular to the optical axis direction of the objective lenses 9 and 10, and performs scanning in the xy direction when detected by the OCT apparatus (details will be described later).

  The light source 1 is a white light source that simultaneously emits temporally coherent short light. For example, a super luminescence diode (SLD), a titanium sapphire laser, a white LED, or the like is applied.

  The illumination light L0 emitted from the light source 1 is collimated to a predetermined beam diameter by the collimating lens 2 and enters the beam splitter 3. The illumination light L0 that has entered the beam splitter 3 is branched into a reference light Lr that travels toward the dispersion correction optical member 14 and a measurement light Lm that travels toward the sample 11.

  The reference light Lr enters the beam splitter 4 through the dispersion correction optical member 14 and the total reflection mirror 8.

  Here, the dispersion correction optical member 14 is an element mainly for maintaining the balance of the interferometer in the OCT apparatus. The balance of the interferometer here refers to the balance of chromatic dispersion of the sample arm and the reference arm of the interferometer. This balance may be lost due to an optical material such as an objective lens and a medium (a culture solution or the like) included in the sample.

  Therefore, the dispersion correcting optical member 14 includes a member for correcting the balance loss caused by the optical material such as an objective lens, and a member for correcting the balance loss caused by the medium included in the sample. . The member for correcting the balance loss caused by the optical material described above has a correction amount corresponding to each optical member arranged on the sample arm. In addition, the member for correcting the balance loss caused by the medium described above is preferably a member whose correction amount is variable in accordance with the type and amount of the medium. As an example, a glass block or the like is used as a member for correcting the balance loss caused by the optical material. Further, as a member for correcting the balance loss caused by the medium, an AOPDF (Acousto-Optic programmable dispersive filter), a prism pair that can be inserted and changed, and the like are used. In addition, when the correction amount and the correction content can be corrected by calculation processing, the dispersion correction optical member 14 may be substituted by calculation processing.

  The reference light Lr is adjusted by such a dispersion correcting optical member 14 so as to have dispersion balanced with the sample arm. The reference light Lr that has passed through the dispersion correction optical member 14 is hereinafter referred to as reference light Lr ′.

  On the other hand, the measurement light Lm enters the beam expander 21 and is collimated to a predetermined beam diameter. If the beam diameter of the light emitted from the light source 1 is sufficiently wide, the beam expander 21 need not be used. Then, the measurement light Lm that has passed through the total reflection mirror 7 is guided to the annular mask 22. The measurement light Lm is formed in an annular shape by the annular mask 22, and the measurement light Lm ′ formed in an annular shape is irradiated on the sample 11 by the objective lens 9. The annular illumination obliquely enters the measurement light with respect to the sample 11 (details will be described later).

  Here, the zonal mask 22 is a measurement that is arranged at the pupil position of the objective lens 9 (pupil position opposite to the sample 11), guided from the beam splitter 3, and converted by the beam expander 21. A part of the light Lm is shielded. Note that other members may be used as long as they are elements that can form a light beam having a width with respect to the sample 11 so as to be obliquely incident. For example, a zoom lens in which a convex axicon lens and a concave axicon lens are combined may be used. As shown in FIG. 2, the annular zone mask 22 is a mask having an annular opening, and the annular zone diameter is d. An annular pattern having a bandwidth ρ is formed at the pupil position of the objective lens 9 due to the balance between the aperture band width and the distance from the annular mask 22 to the pupil position of the objective lens 9. At this time, the relationship of the following equation holds for the depth of focus.

Depth of focus = 2ρf / D˜ρ / NA (Formula 1)
In Equation 1, f represents the focal length of the objective lens 9, and NA represents the effective NA of the objective lens. Furthermore, the ring zone mask 22 can change the ring zone diameter D and the band width ρ of the opening according to control by the control device 17 (details will be described later).

  Measurement light (hereinafter referred to as measurement light Lm ′) formed annularly by the annular mask 22 is guided to the objective lens 9.

  The measurement light Lm ′ is condensed by the objective lens 9 and irradiated toward one point (condensing point) in the deep part of the sample 11. Note that the relative position in the z direction between the sample 11 and the objective lens 9 is adjusted in advance so that the focal plane of the objective lens 11 covers the region where the object to be observed (such as cultured cells) in the sample 11 is present.

  In the sample 11 in the irradiation region of the measurement light Lm ′ (hereinafter referred to as “irradiation spot”), diffracted light of various angles may be generated. Of these diffracted lights, the light traveling in the same direction as the measurement light Lm ′ toward the condensing point is captured by the objective lens 10 through the aperture 13.

  The specification of the objective lens 10 is the same as the specification of the objective lens 9 described above, and the arrangement destination of the objective lens 10 is a position facing the objective lens 9 with the sample 11 interposed therebetween. The focal plane of the objective lens 10 coincides with the focal plane of the objective lens 9, and the focal point of the objective lens 10 coincides with the focal point of the objective lens 9.

  Further, the objective lens 9 has a variable numerical aperture NA by being controlled by the control device 17 or by arranging a revolver or the like on which the objective lens 9 is installed.

  Hereinafter, of the transmitted light traveling from the irradiation spot toward the objective lens 10, the light captured by the objective lens 10 is referred to as “measurement light Lm”. The measurement light Lm ″ passes through the objective lens 10 and then enters the beam splitter 4.

  Here, details from the illumination light L0 emitted from the light source 1 to the measurement light Lm ″ incident on the beam splitter 4 will be described with reference to FIG.

  3 is an optical path diagram from the illumination light L0 emitted from the light source 1 to the measurement light Lm ″ incident on the beam splitter 4. As shown in FIG. 3, the illumination light L0 emitted from the light source 1 is a collimating lens. The measurement light Lm is converted to a predetermined beam diameter by the beam expander 21. Further, the measurement light Lm that has passed through the total reflection mirror 7 is applied to the annular mask 22. The measurement light Lm is formed in an annular shape by the annular mask 22, and the measurement light Lm ′ formed in an annular shape is irradiated onto the sample 11 by the objective lens 9. At this time, the measurement light Lm ′ is The sample 11 is obliquely incident on the sample 11. In the sample 11, diffracted light is generated according to the contents of the observation object of the sample 11. Of the diffracted light, the sample 11 is transmitted. The component is captured by the objective lens 10. However, at this time, the aperture 13 blocks a part of the transmitted light (0th-order diffracted light component), which, as shown in FIG. It is a stop for mainly taking out the scattered component by the sample 12 among the measurement light which was arrange | positioned between the objective lenses 10 and permeate | transmitted the sample 12. FIG.

  FIG. 4 shows an enlarged view of the vicinity of the aperture 13. As shown in FIG. 4, the aperture 13 has a predetermined aperture, and transmits only the diffracted light in the vicinity of the center (hatched portion in FIG. 3) among the diffracted light transmitted through the sample 11, and transmits the other light. Cut off.

  Then, the measurement light Lm ″ incident on the beam splitter 4 is combined with the reference light Lr ′ incident on the beam splitter 4 from the reference arm side, and travels toward the cylindrical lens 15. The combined reference light Lr. 'And the measurement light Lm ”are collectively referred to as“ combined light ”or“ interference light ”. The interference light directed toward the cylindrical lens 15 is guided by the cylindrical lens 15 to the entrance slit of the spectrum detector 16.

  As shown in FIG. 1, the spectrum detector 16 includes a slit plate 16a having a slit opening at a condensing point of the interference light, a collimator mirror 16b for converting the interference light that has passed through the slit plate 16a into parallel light, A reflective diffraction grating 16c that separates the interference light that has become parallel light into a plurality of wavelength components, a condensing mirror 16d that condenses the wavelength components at positions shifted from each other, and each of the light that is condensed at positions shifted from each other. And a line sensor 16e for individually detecting the intensity of the wavelength component. With this configuration, the spectrum detector 16 generates an intensity signal (that is, a spectrum signal) for each wavelength component of the interference light. This spectrum signal is sent to the control device 17.

  Here, the sample stage 12 described above can displace the sample 11 in the xy direction under the control of the control device 17. Therefore, when the sample stage 12 is driven, the irradiation spot on the sample 11 moves in the xy direction.

  Therefore, the control device 17 drives the sample stage 12 to perform two-dimensional scanning on the sample 11 in the xy direction with the irradiation spot, and when the irradiation spot is at each xy position, drives the line sensor 16e to obtain the spectrum signal. By taking in, the spectrum signal of each xy position is acquired. These spectrum signals are sent to the arithmetic unit 18.

  The computing device 18 obtains structural information in the z direction at each xy position by individually Fourier-transforming the spectrum signal at each xy position. Thereby, the three-dimensional image information in the xyz direction becomes known (details will be described later). The arithmetic unit 18 displays the structural information of the sample 11 that has become known on a monitor (not shown).

  The control device 17 controls the z resolution in OCT by controlling the revolver holding the objective lens 9 of the above-described OCT device and the annular zone mask 22 according to the sample 11. Such control is for performing detection with an optimum resolution in accordance with the size and shape of the observation object included in the sample 11.

  The z resolution in the present embodiment depends not only on the coherence length but also on the numerical aperture NA of the objective lens 9. It is known that two structures located at a distance L1 apart in the depth direction (z direction) are measured by contracting (1-cos θ) times when performing interference measurement.

  On the other hand, it is known that the optical path length difference of the structure in which the distance in the z direction is separated by L1 is 2 * L1 in the normal reflection type OCT. Therefore, the z resolution in the above-described transmission type and illumination by oblique incidence is 2 / (1-cos θ) times the z resolution in the OCT having the normal reflection type configuration.

  The numerical aperture NA of the objective lens 9 can be expressed by the following equation.

NA = sin θ = d / 2f (Expression 2)
In Expression 2, d indicates an effective pupil system of the objective lens 9, and f indicates a focal length of the objective lens 9.

From Equation 2, it can be seen that the numerical aperture NA of the objective lens 9 depends on the effective pupil system d and the focal length f of the objective lens. Further, it can be seen from Equation 1 that if the numerical aperture NA of the objective lens 9 can be controlled, the depth of focus is also controlled. Since the depth of focus and the z resolution are in a trade-off relationship, the z resolution can be increased by reducing the depth of focus.
Here, the numerical aperture NA is a value unique to the objective lens 9. Therefore, the effective pupil diameter d and the focal length f of the objective lens 9 itself are also unique values. In order to change the effective pupil diameter, it is conceivable that the upper limit is d and the effective pupil diameter is reduced by a diaphragm or the like. The z resolution can be increased as the effective pupil diameter is increased. In order to make the depth of focus deep and to make full use of the effective pupil diameter d of the objective lens 9, a stop having a comparable diameter may be used.

  It can also be seen from Equation 1 that the band width of the ring formed by the ring mask 22 also contributes to the z resolution. The narrower the band width ρ, the shallower the depth of focus and the higher the z resolution. For this reason, the z resolution can be controlled by varying the size of the annular zone with the upper limit of the outer diameter of the annular zone formed on the pupil by the annular zone mask 22 as d.

  Further, in order to perform detection with an optimal resolution according to the size and shape of the object to be observed, the effective pupil system d of the objective lens 9 and the ring zone diameter D of the ring mask 22 are determined according to the object to be observed. Should be optimized. This control can also optimize the depth of focus of the objective lens 9.

[Second Embodiment]
The OCT apparatus according to the second embodiment of the present invention will be described below.

  FIG. 5 is a configuration diagram of the OCT apparatus according to the second embodiment. In FIG. 5, the same components as those shown in FIG. As shown in FIG. 5, the OCT apparatus according to the present embodiment is an OCT apparatus having both the configurations of the transmission-type OCT apparatus and the reflection-type OCT apparatus described in the first embodiment.

  As shown in FIG. 5, the OCT apparatus of this embodiment includes a flipper mirror 51, total reflection mirrors 52 and 53, a dispersion correction optical member 54, a plane mirror (reference mirror) 55 in addition to the components shown in FIG. Is placed.

  The flipper mirror 51 is disposed between the collimator lens 2 and the beam splitter 3, and guides the illumination light L 0 transmitted through the collimator lens 2 to either the beam splitter 3 or the total reflection mirror 52. The total reflection mirrors 52 and 53 guide the illumination light L 0 guided by the flipper mirror 51 to the beam splitter 4.

  The dispersion correction optical member 54 is a reflection-type OCT dispersion correction optical member, and the configuration thereof is the same as that of the dispersion correction optical member 14 described in the first embodiment. Further, the plane mirror (reference mirror) 55 is a mirror used at the time of reflective OCT, and is the same mirror as the reference mirror 41 described in the second embodiment. The dispersion correcting optical member 54 and the reference mirror 55 can be inserted into and removed from the optical path (details will be described later).

  In FIG. 5, illustration of the control device 17 and the arithmetic device 18 and illustration of arrows of the control system are omitted. The control device 17 controls each part of the light source 1, the objective lens 9, the sample stage 12, the spectrum detector 16, and the annular mask 22, and interlocks each part of the flipper mirror 51, the dispersion correction optical member 54, and the reference mirror 55. And control. Moreover, the control apparatus 17 sends the spectrum signal acquired by the spectrum detector 16 to the calculating apparatus 18 similarly to 1st Embodiment.

  Here, a difference in characteristics between the transmission type OCT apparatus and the reflection type OCT apparatus will be described. FIG. 6A is an example when observing an observation object (cell C) with a transmission type OCT apparatus, and FIG. 6B is an example when observing the observation object (cell C) with a reflection type OCT apparatus. It is an example. As shown in FIG. 6A, the transmission type OCT apparatus is suitable for observation of a side wall (portion surrounded by a dotted line in FIG. 6A). On the other hand, the reflective OCT apparatus is suitable for observation in the horizontal plane direction (portion surrounded by a dotted line in FIG. 6B).

  Therefore, the OCT apparatus according to the present embodiment performs detection more suitable for an object to be observed by having both configurations of a transmission type OCT apparatus and a reflection type OCT apparatus.

  First, transmissive OCT will be described. The control device 17 executes transmissive OCT using each part in the frame of A1 in FIG. The control device 17 guides the illumination light L0 transmitted through the collimator lens 2 to the beam splitter 3 by turning off the flipper mirror 51. At this time, the control device 17 puts the dispersion correcting optical member 54 and the reference mirror 55 in a state of being separated from the optical path. The illumination light L0 guided to the beam splitter 3 passes through each part and reaches the spectrum detector 16 as described in the first embodiment. Since the processing in each part is the same as that in the first embodiment, description thereof is omitted.

  Next, the reflection type OCT will be described. The control device 17 executes reflection type OCT using each part in the frame A2 in FIG. The control device 17 guides the illumination light L0 transmitted through the collimator lens 2 to the total reflection mirror 52 by turning on the flipper mirror 51. At this time, the control device 17 puts the dispersion correcting optical member 54 and the reference mirror 55 into the optical path.

  The illumination light L 0 guided to the total reflection mirror 52 is guided to the beam splitter 4 through the total reflection mirror 53. Then, the light is branched into a reference light Lr traveling toward the reference mirror 55 inserted in the optical path and a measurement light Lm traveling toward the sample 11.

  When the reference light Lr enters the reference mirror 55 from the front via the dispersion correction optical member 54, the reference light Lr is reflected by the reference mirror 55, and returns to the beam splitter 4 again through the dispersion correction optical member 54.

  On the other hand, when the measurement light Lm is incident on the objective lens 10 (from the side opposite to the case of the transmission type OCT), the measurement light Lm receives the condensing action of the objective lens 10 and travels to one point (condensing point) in the deep part of the sample 11. And concentrate. Note that the relative position in the z direction between the sample 11 and the objective lens 10 is adjusted in advance so that the focal plane of the objective lens 10 is on the region where the object to be observed (cultured cells or the like) in the sample 11 is present. At this time, the control device 17 opens the aperture 13.

  Of the reflected light at the irradiation spot of the sample 11, the light that follows the optical path of the measurement light Lm toward the condensing point in the opposite direction is captured by the objective lens 10. Then, the measurement light Lm ′ captured by the objective lens 10 follows the optical path of the measurement light Lm in the reverse direction and enters the beam splitter 4.

  The measurement light Lm ′ that has entered the beam splitter 4 combines the optical path with the reference light Lr ′ that has returned to the beam splitter 4 and travels toward the cylindrical lens 15. Here, the optical path length of the single optical path of the reference light (the optical path length of the reference arm) and the optical path length of the single optical path of the measurement light (optical path length of the measurement arm) are equalized by the action of the optical member 54 for dispersion correction. I'm doing it.

  Then, the interference light directed toward the cylindrical lens 15 is guided by the cylindrical lens 15 to the entrance slit of the spectrum detector 16. The configuration and operation of the spectrum detector 16 are the same as those in the first embodiment.

  In accordance with the principle described in the first embodiment, the control device 17 converts each part such as the objective lens 9, the annular mask 22, the flipper mirror 51, the dispersion correction optical member 54, and the reference mirror 55 of the OCT device described above into the sample 11. Accordingly, the z resolution in OCT is controlled by controlling in conjunction with each other. By such control, it becomes possible to irradiate measurement light from various directions to the object to be observed included in the sample 11, and to capture the three-dimensional structure evenly.

  As described above, according to the present embodiment, in the OCT apparatus capable of detecting the intensity of interference light by both the transmission type and the reflection type, the numerical aperture of the objective lens is controlled in accordance with the content of detection by the detection means. And switching control between the transmission type and the reflection type. Therefore, detection according to the object to be observed can be made more finely. In particular, according to the present embodiment, it can be expected that omnidirectional information of an object to be observed is obtained by performing OCT by appropriately switching between a transmission type and a reflection type.

[Supplement of the second embodiment]
In the OCT apparatus according to the second embodiment, the objective lens 10 that functions as the objective lens next to the reflective OCT is changed to an objective lens having a variable numerical aperture NA in the same manner as the objective lens 9. Alternatively, the z resolution may be variable. An OCT apparatus having both a configuration of a reflective OCT apparatus with variable z resolution and a configuration of a normal transmission OCT apparatus with unchanged resolution is also effective as a specific aspect of the present invention.

[Modification of Embodiment]
The OCT apparatus according to the first and second embodiments described above employs a method (stage scan type) in which the sample 11 side is displaced by moving the sample stage 12, but the irradiation spot side is displaced. A method (beam scanning type) may be adopted. Two methods may be selectively used or may be used in combination.

  Moreover, although the OCT apparatus of each embodiment mentioned above employ | adopted the method (Fourier domain type) which carries out the spectral detection of the white interference light using a light source (white light source), it scans a light source wavelength and interferes with each wavelength. A method of detecting light in a time division manner (wavelength scanning type) may be employed.

  Incidentally, when the Fourier domain type is adopted, it is not necessary to perform spectral detection, so by using an imaging device instead of the spectrum detector 18, the interference light intensity at each position in the xy direction on the sample 11 is collectively displayed. It may be detected.

  Moreover, although the OCT apparatus of each embodiment mentioned above employ | adopted the method (Fourier domain type) which carries out the spectral detection of the interference light using a light source (white light source), it uses a light source (white light source), and is measured. You may employ | adopt the method (time domain type) which scans the optical path length difference of light and reference light, and detects white interference light for every scanning position.

  Incidentally, when the time domain type is adopted, it is not necessary to perform spectral detection, so by using an image sensor instead of the spectrum detector 18, the interference light intensity at each position in the xy direction on the sample 11 is collectively displayed. It may be detected.

  In the OCT apparatus of each embodiment described above, a polarization component may be used. For example, there is a difference between the polarization direction of the reference light toward the detection means and the polarization direction of the measurement light toward the object to be observed, and the reference light toward the detection means from the measurement light toward the detection means By removing different components, detection using a polarization component can be performed.

DESCRIPTION OF SYMBOLS 1 ... Light source, 3 and 4 beam splitter, 9, 10 ... Objective lens, 11 ... Sample, 13 ... Aperture, 14, 54 ... Optical member for dispersion | distribution correction, 16 ... Spectrum detector, 17 ... Control apparatus, 18 ... Arithmetic unit , 22 ... ring zone mask, 42 ... optical scanner

Claims (10)

First branching means for branching incident light into first reference light and first measurement light;
A first illumination optical system for obliquely illuminating the first measurement light with respect to the object to be observed;
A first observation optical system for observing transmitted light from the observation object illuminated obliquely;
A first reference optical system for forming the first reference light based on the first measurement light;
First combining means for combining the first reference light and the transmitted light from the object to be observed;
First detection means for detecting first interference light between the first reference light and the transmitted light from the object to be observed;
A transmission type observation apparatus comprising: first position information acquisition means for acquiring position information of the object to be observed along the optical axis direction of the observation optical system;
Second branching means for branching incident light into second reference light and second measurement light;
A second illumination optical system that illuminates the second measurement light on the object to be observed;
A second observation optical system for observing reflected light from the illuminated object to be observed;
A second reference optical system for forming the second reference light based on the second measurement light;
Second combining means for combining the second reference light and the reflected light from the object to be observed;
Second detection means for detecting second interference light between the second reference light and reflected light from the object to be observed;
An observation apparatus comprising: a reflection type observation apparatus including a second position information acquisition unit configured to acquire position information of the object to be observed along an optical axis direction of the observation optical system. The observation apparatus according to claim 1,
An observation device comprising switching means for switching between a transmission type observation device and a reflection type observation device. In the observation apparatus according to claim 1 or claim 2,
The observation apparatus, wherein the first detection means and the second detection means are the same. In the observation apparatus according to claim 1 to claim 3,
The first illumination optical system includes an oblique incident means for obliquely incident on the object to be observed. In the observation apparatus according to any one of claims 1 to 4,
The first measuring light or the second illuminating optical system, the second illuminating optical system, the first observing optical system, or the first observing light in the direction orthogonal to at least one optical axis of the second observing optical system. An observation apparatus comprising: a scanning unit that scans the second measurement light. In the observation apparatus as described in any one of Claims 1-5,
At least one of the first detection means or the second detection means is:
An observation device, wherein the observation device is a spectrum detector that spectrally detects the first interference light or the second interference light. In the observation apparatus according to any one of claims 1 to 6,
A half-wave plate or a quarter-wave plate disposed in the first reference light or the first measurement light;
A first polarizing element for making light of a predetermined polarization incident on the first branching means;
A second polarizing element that transmits a part of the first interference light including a polarization direction determined based on the predetermined polarization;
An observation apparatus comprising: a first control unit that simultaneously changes a polarization direction transmitted by the first polarization element and a polarization direction transmitted by the second polarization element. In the observation apparatus according to any one of claims 1 to 7,
A half-wave plate or a quarter-wave plate disposed in the second reference light or the second measurement light;
A third polarizing element for entering light of a predetermined polarization into the second branching unit;
A fourth polarizing element that transmits a part of the second interference light including a polarization direction determined based on the predetermined polarization;
An observation apparatus comprising: a second control unit that simultaneously changes a polarization direction transmitted by the third polarization element and a polarization direction transmitted by the fourth polarization element. The observation device according to claim 8,
The observation apparatus, wherein the second polarizing element and the fourth polarizing element are in the same position. The incident light is branched into a first reference light and a first measurement light,
The first measurement light is obliquely incident on the object to be observed,
Observe the transmitted light from the observation object illuminated obliquely,
Forming the first reference light based on the first measurement light;
Detecting interference light obtained by combining the first reference light and the transmitted light from the object to be observed;
A transmission type observation method for acquiring position information of the object to be observed along the optical axis direction of the observation optical system;
The incident light is branched into a second reference light and a second measurement light,
Illuminating the object to be observed with the second measurement light;
Observe the reflected light from the illuminated object to be observed,
Forming the second reference light in the previous period based on the second measurement light;
Detecting interference light obtained by combining the second reference light and the reflected light from the object to be observed;
A reflection type observation method for acquiring position information of the object to be observed along the optical axis direction of the observation optical system;
An observation method characterized by switching between the transmission type observation method and the reflection type observation method.

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