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WO2009041290A1 - Système optique et endoscope comprenant ce système - Google Patents

Système optique et endoscope comprenant ce système Download PDF

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Publication number
WO2009041290A1
WO2009041290A1 PCT/JP2008/066504 JP2008066504W WO2009041290A1 WO 2009041290 A1 WO2009041290 A1 WO 2009041290A1 JP 2008066504 W JP2008066504 W JP 2008066504W WO 2009041290 A1 WO2009041290 A1 WO 2009041290A1
Authority
WO
WIPO (PCT)
Prior art keywords
group
optical system
image
transparent medium
central axis
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2008/066504
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English (en)
Japanese (ja)
Inventor
Takayoshi Togino
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Olympus Corp
Original Assignee
Olympus Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Olympus Corp filed Critical Olympus Corp
Publication of WO2009041290A1 publication Critical patent/WO2009041290A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B23/00—Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices
    • G02B23/24—Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes
    • G02B23/2407—Optical details
    • G02B23/2423—Optical details of the distal end
    • G02B23/243—Objectives for endoscopes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/00064—Constructional details of the endoscope body
    • A61B1/00071—Insertion part of the endoscope body
    • A61B1/0008—Insertion part of the endoscope body characterised by distal tip features
    • A61B1/00096—Optical elements
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/04—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor combined with photographic or television appliances
    • A61B1/041—Capsule endoscopes for imaging
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
    • G02B17/08—Catadioptric systems
    • G02B17/0856—Catadioptric systems comprising a refractive element with a reflective surface, the reflection taking place inside the element, e.g. Mangin mirrors

Definitions

  • the present invention relates to an optical system and an endoscope using the same, and more particularly to an imaging optical system or a projection optical system having a function of forming an image around a rotationally symmetric axis as an annular image on an image sensor. is there.
  • the present invention has been made in view of such a situation of the prior art, and the purpose thereof is to enable a wide observation angle of view to be imaged on an image sensor with a simple configuration, and to achieve a compact and inexpensive optical.
  • a system and an endoscope using the system are provided.
  • the optical system of the present invention that achieves the above object is an optical system that is rotationally symmetric about the central axis in a cross section including the central axis, wherein the optical system is an aperture disposed on the object side on the central axis.
  • a transparent medium having a refractive index greater than 1 disposed on the image plane side of the opening the transparent medium including the first transmission surface disposed on the central axis in the vicinity of the opening,
  • the first reflecting surface is disposed on the image plane side from the first transmission surface and has a concave surface facing the image surface side.
  • the first reflecting surface is disposed on the opposite side of the image surface from the first reflecting surface, and the concave surface is directed to the image surface side.
  • the transmission surface is formed of a curved surface, and the light beam incident on the transparent medium passes through the aperture in the order of forward ray tracing, and the first transmission surface. Through the transparent medium, reflected by the first reflecting surface to the opposite side of the image plane, reflected by the second reflecting surface to the image plane side, and passed through the second transmitting surface from the transparent medium to the image plane.
  • a substantially Z-shaped first optical path going out to the side, and at least a portion of the first optical path between the first reflecting surface and the second reflecting surface is configured on one side with respect to the central axis.
  • the intermediate image is formed in an annular shape on the image plane without forming an intermediate image in the first optical path.
  • the first reflecting surface is configured to be reflected by a total reflection action and a reflection coating, and the reflecting coating is applied only in the vicinity of the central axis of the first reflecting surface.
  • the first transmission surface and the second reflection surface are arranged on the object side of the transparent medium.
  • the first transmission surface and the second reflection surface may have the same shape at the same position.
  • the first reflection surface and the second transmission surface may be arranged on the image surface side of the transparent medium.
  • first reflection surface and the second transmission surface have the same shape at the same position.
  • a third transmission surface is provided in the vicinity of the central axis of the first reflection surface, and a light beam incident on the transparent medium passes through the opening in the order of forward ray tracing, passes through the first transmission surface, and passes through the first transmission surface.
  • a second optical path is formed which enters inside and passes through the third transmission surface and exits from the transmission medium to the image plane side.
  • a lens is disposed on the object side and / or the image plane side of the transparent medium.
  • the transparent medium is formed by joining a first transparent medium and a second transparent medium having different refractive indexes.
  • R 1 be the curvature of the first reflecting surface and R 2 be the curvature of the second reflecting surface. 0.2 ⁇ R 1 / R 2 ⁇ 3- ⁇ ⁇ ⁇ (3) The condition is satisfied.
  • the first reflecting surface and the second reflecting surface are each composed of a rotationally symmetric aspherical surface.
  • the first reflecting surface and the second reflecting surface are spherical surfaces.
  • the present invention for achieving the above object is an endoscope using the optical system.
  • FIG. 2 is a cross-sectional view taken along the central axis of the optical system according to Example 1 of the present invention. (Fig. 3)
  • FIG. 2 is a transverse aberration diagram for the whole optical system of Example 1.
  • FIG. 5 is a cross-sectional view taken along the central axis of the optical system of Example 2-1 of the present invention.
  • FIG. 10 is a diagram showing transverse aberration diagrams of the first optical path of the whole optical system of Example 2-1 and 2-2.
  • FIG. 6 is a cross-sectional view taken along the central axis of the optical system of Example 2-2 of the present invention.
  • FIG. 10 is a diagram showing a lateral aberration diagram of the second optical path of the whole optical system of Example 2-2. (Fig. 8)
  • FIG. 6 is a cross-sectional view taken along the central axis of the optical system of Example 3-1 of the present invention.
  • FIG. 10 is a diagram showing lateral aberration diagrams of the first optical path of the entire optical system of Examples 3-1 and 3-2.
  • FIG. 5 is a cross-sectional view taken along the central axis of the optical system of Example 3-2 of the present invention.
  • FIG. 10 is a diagram showing a lateral aberration diagram of the second optical path of the whole optical system of Example 3-2. (Fig. 1 2)
  • FIG. 6 is a transverse aberration diagram for the whole optical system of Example 4.
  • FIG. 3 is a diagram showing an example in which the optical system of the present invention is used as a photographing optical system at the tip of an endoscope.
  • FIG. 3 is a diagram showing an example in which the optical system of the present invention is used as a photographing optical system for a capsule endoscope.
  • FIG. 3 is a diagram showing an example in which the optical system of the present invention is used as an imaging optical system for an automobile.
  • FIG. 3 is a diagram showing an example in which the optical system of the present invention is used as a photographing optical system for photographing an outdoor subject.
  • optical system of the present invention will be described below based on examples.
  • FIG. 2 is a cross-sectional view taken along the central axis (rotation symmetry axis) 2 of the optical system 1 of Example 1 described later.
  • FIG. 2 is a cross-sectional view taken along the central axis (rotation symmetry axis) 2 of the optical system 1 of Example 1 described later.
  • An optical system 1 according to the present invention is rotationally symmetric with respect to a central axis 2 and includes an aperture S and a transparent medium L, and forms or projects an image without forming an intermediate image in the optical path. It is.
  • the parallel plate near the image plane 5 is the cover glass C b 2 of the image sensor.
  • the optical system 1 of Example 1 is configured so as to be rotationally symmetric around the central axis 2 in a cross section including the central axis 2, and is disposed on the object side on the central axis 2, and the image plane of the aperture S
  • a transparent medium L having a refractive index greater than 1 and the transparent medium L is a first transmission surface disposed on the central axis 2 near the opening S.
  • a first optical path A is formed, and at least the rear first group first reflective surface 2 2 and the rear first group second reflective surface 2 3 of the first optical path A are configured only on one side with respect to the central axis 2.
  • an intermediate image is not formed in the first optical path A, but is formed in an annular shape on the image plane 5.
  • the aperture S is in the vicinity of the first transmission surface 21 in the first group on the rear side of the object side. If the aperture S is arranged on the image side of the transparent medium L of the present invention, astigmatism is greatly generated and a flat image is generated. Cannot be formed. In addition, the tilt angle of the main light beam is increased, resulting in poor telecentricity. Furthermore, interference between the effective diameters of the rear first group first transmission surface 21 and the rear first group second reflection surface 23 occurs, and it becomes impossible to increase the angle of view. [0 0 2 7]
  • the rear first group first reflecting surface 2 2 and the rear first group second reflecting surface 2 3 face the concave side toward the image side, and the rear first group first reflecting surface 2 2 and the rear first group second reflecting surface 2 3 It is important that the optical path between is constructed on one side without straddling the axis of rotational symmetry and is a Z-shaped optical path.
  • the reflecting surface between the transmitting surfaces and configuring the reflecting surface as an internal reflecting surface it is possible to reduce the occurrence of aberrations such as field curvature.
  • the inclination of the light ray that strikes the rear first group first reflecting surface 2 2 becomes smaller than that in the air, a good result is obtained for a wide angle of view.
  • the rear first group first reflecting surface 2 2 is configured so that light having a wide angle of view is reflected by total reflection, and the incident angle at which the rear first group first reflecting surface 2 2 is not totally reflected near the center of the angle of view. It is preferable to apply a reflective coating 4 a to the center of the rear first group first reflecting surface 22 so as to reflect the light beam. As a result, it is possible to capture an image of the center of the angle of view. Furthermore, since the rear part of the first group 1st reflecting surface 2 2 is totally reflected, it is desirable that this part is not subjected to reflection coating. As a result, the central beam is not prevented from exiting the optical system.
  • the rear first group first transmission surface 21 and the rear first group second reflection surface 23 be disposed close to the object side of the transparent medium L. This makes the mutual plane This reduces the interference of light rays at the lens and makes it possible to secure a wide angle of view.
  • the rear first group first reflecting surface 2 2 and the rear first group second transmitting surface 24 be disposed close to the image surface 5 side of the transparent medium L. This makes it possible to shorten the transparent medium and the image plane 5. The total length of the optical system can be shortened.
  • the rear first group second reflecting surface 23 be provided with a reflective coating 4 b on the periphery, and the central portion is provided with the rear first group first transmitting surface 21 or the opening S. It is desirable not to ping.
  • the rear first group first reflecting surface 2 2 and the rear first group second transmitting surface 2 4 are preferably configured in the same place and in the same shape. With this configuration, it is possible to partially use total reflection for the rear first group first reflecting surface 22, and a wide angle of view of the optical system can be obtained.
  • the rear first group first transmitting surface 2 1 and the rear first group second reflecting surface 2 3 are preferably formed in the same place and in the same shape. This configuration improves workability.
  • the rear first group third reflecting surface 25 is provided near the central axis of the rear first group first reflecting surface 22, and the light beam incident on the transparent medium L has an aperture S in the order of forward ray tracing.
  • the second optical path B is formed that exits from the transparent medium L to the image plane 5 side. This makes it possible to capture the image of the central part.
  • a lens is disposed on the object side and / or the image plane side of the transparent medium L. With this, the angle of view can be increased.
  • the transparent medium L is configured by joining a first transparent medium and a second transparent medium having different refractive indexes, so that lateral chromatic aberration and the like can be reduced.
  • conditional expression (1) when the lower limit is exceeded, the telecentricity deteriorates, and in particular, when using an image sensor such as C CD, the amount of peripheral light is insufficient. If the upper limit is exceeded, the outer diameter of the optical system becomes too large and the optical system becomes large.
  • Conditional expression (2) defines the total length of the optical system with respect to the image height. If the lower limit is exceeded, the telecentricity also deteriorates and the peripheral light quantity is insufficient. If the upper limit is exceeded, the total length becomes too long, and a compact optical system cannot be constructed.
  • Conditional expression (3) regulates the ratio of the power of the two reflecting surfaces. If the lower limit is exceeded, the radius of curvature of the rear first group, first reflecting surface 2 2 becomes smaller, and the rear first group first 2 Compared to the positive power of the reflecting surface 2 3, the negative power of the rear 1st group 1st reflecting surface 2 2 becomes larger and the total length of the optical system cannot be shortened. When the upper limit is exceeded, the curvature of the rear first group second reflecting surface 23 becomes smaller, the positive power of the rear first group second reflecting surface 23 becomes too large, and a large curvature of field on the object side occurs.
  • all the embodiments are configured by a spherical surface, but may be configured by a normal aspherical surface.
  • the parallel plane on the object side is for protecting the optical system and may be omitted.
  • the parallel plane on the image side is for protecting the image sensor and may be omitted.
  • the coordinate system uses the point where the diaphragm and the center axis 2 intersect as the origin O of the decentered optical surface, and the direction perpendicular to the center axis 2 as the Y axis direction.
  • the plane of the paper in Fig. 1 is the Y-Z plane.
  • FIG. 3 shows a lateral aberration diagram of the entire optical system of this example.
  • the angle shown in the center indicates (horizontal field angle, vertical field angle), and lateral aberrations in the Y direction (meridinal direction) and X direction (sagittal direction) at that field angle.
  • a negative field angle means a clockwise angle in the Y-axis positive direction for the horizontal field angle, and a clockwise angle in the positive X-axis direction for the vertical field angle. same as below.
  • the transmission surface and the reflection surface of the transparent medium L having a refractive index larger than 1 concentrically symmetric with respect to the central axis 2 of the optical system 1 are configured as spherical surfaces that are partially shared in the optical path. is there.
  • the optical system 1 includes a front group G f, a rear group G b, and an aperture S arranged coaxially with the central axis 2 between the front group G f and the rear group G b.
  • the rear group G b It consists of rear 1 group G b 1 and rear 2 group G b 2.
  • the front group G f consists of a front group cover glass C f whose refractive index is rotationally symmetric about the central axis 2 and greater than 1.
  • the front cover glass C f is composed of parallel flat plates, and the front group first transmission surface 1 1 and the front group second transmission surface 1 2 formed on the image side with respect to the front group first transmission surface 1 1. And have.
  • Rear group 1 G b 1 has a rotationally symmetric refractive index greater than 1 around the central axis 2 It consists of a transparent medium.
  • the transparent medium L is formed on the image side with respect to the rear first group first transmission surface 2 1 and the rear first group first transmission surface 2 1 formed of a spherical surface on the central axis 2, and a part of the reflection coating 4 a
  • the rear 1st group 1st reflecting surface 2 2 having negative power and the rear 1st group 1st reflecting surface 2 2 are arranged on the opposite side of the image plane 5 and the reflective coating 4b is used.
  • a rear first group second reflecting surface 2 3 having a positive power and a rear first group second reflecting surface 2 4 having a positive power.
  • Rear 1st group 1st transmission surface 2 1 and rear 1st group 2nd reflection surface 2 3 have the same position and the same shape, Rear 1st group 1st reflection surface 2 2 and Rear 1st group 2nd transmission surface 2 4 are the same It consists of the same shape.
  • the rear 2 group G b 2 is composed of a rear 2 group cover glass C b 2 force whose refractive index rotationally symmetric about the central axis 2 is greater than 1.
  • Rear 2nd group cover glass Cb2 consists of parallel flat plate, rear 2nd group 1st transmission surface 3 1 and rear 2nd group 1st transmission surface 3 1 formed on the image side with respect to rear 2nd group 1st transmission surface 3 1 Surface 3 2.
  • the optical system 1 forms the optical path A.
  • the light beam incident from the object plane of optical system 1 is the front group of front group cover glass C f, first transmission surface 1 1, front group second transmission surface 1 2, front group cover glass C f and transparent medium L And enters the transparent medium L through an opening S arranged coaxially with the central axis 2.
  • the transparent medium L it enters after the first group 1 first transmission surface 2 1, and the rear 1 group 1 reflection surface 2 2 is partly reflective coating 4 a, and part is totally reflected and opposite to the image surface 5 Reflected on the back, 1st group 2nd reflecting surface 2 3 Reflected on the image surface 5 side by the reflective coating 4b, and then 1st group 2nd transmitting surface 2 4 It has a light path.
  • the rear 2nd group cover glass Cb 2 passes through the rear 2nd group 1st transmission surface 3 1 and the rear 2nd group 2nd transmission surface 3 2 to a predetermined radial position away from the central axis 2 of the image plane 5. It forms an image in an annular shape.
  • Example 1 The specification of Example 1 is Angle of view 20.00-60.0 °
  • FIG. 5 shows a lateral aberration diagram of the first optical path in the optical system of this example.
  • the transmission surface and the reflection surface of the transparent medium L having a refractive index larger than 1 concentrically symmetric with respect to the central axis 2 of the optical system 1 are configured as spherical surfaces that are partially shared in the optical path. is there.
  • the optical system 1 includes a front group, a rear group G b, and an aperture S arranged coaxially with the central axis 2 between the front group G f and the rear group G b, and the rear group G b It consists of group 1 G b 1 and rear group 2 G b 2.
  • the front group G ⁇ consists of a front group cover glass C f having a refractive index rotationally symmetric around the central axis 2 greater than 1.
  • the front cover glass C f is composed of a parallel plate, and includes a front group transmission surface 1 1 and a front group second transmission surface 1 2 formed on the image side with respect to the front group first transmission surface 1 1.
  • the rear group 1 G b 1 consists of a transparent medium with a refractive index greater than 1 which is rotationally symmetric about the central axis 2.
  • the transparent medium L is formed on the image side with respect to the rear first group first transmission surface 2 1 and the rear first group first transmission surface 2 1 formed of a spherical surface on the central axis 2, and a part of the reflection coating 4 a
  • the rear first group first reflecting surface 2 2 having negative power and the rear first group first reflecting surface 2 2 are arranged on the opposite side of the image plane 5, and the reflection coating 4 b is positive.
  • Rear 1st group 1st transmission surface 2 1 and rear 1st group 2nd reflection surface 2 3 have the same position and the same shape
  • Rear 1st group 1st reflection surface 2 2 and Rear 1st group 2nd transmission surface 2 4 are the same It consists of the same shape.
  • the rear 2 group G b 2 is composed of the rear 2 group cover glass C b 2 having a rotationally symmetric refractive index greater than 1 around the central axis 2.
  • Rear 2nd group cover glass Cb2 consists of parallel flat plates, and rear 2nd group 1st transmission surface 3 1 and rear 2nd group 1st transmission surface 3 1 are formed on the image side 2nd rear group 2 And a second transmission surface 3 2.
  • the optical system 1 forms the first optical path A.
  • the light beam incident from the object plane of the optical system 1 is the front group first transmission surface 1 1, front group second transmission surface 1 2, and front group cover glass C C of the front group cover glass C f; It enters the transparent medium L through an opening S arranged coaxially with the central axis 2 between f and the transparent medium L.
  • the transparent medium L it enters after the first group 1 first transmission surface 2 1, and part of the rear 1 group 1 reflection surface 2 2 is partially reflective coating 4 a, and the other part is reflected to the opposite side of the image surface 5 by total reflection.
  • the rear group 2 cover glass Cb 2 passes through the rear group 2 first transmitting surface 3 1 and the rear group 2 second transmitting surface 3 2, and is positioned at a predetermined radial position away from the central axis 2 of the image surface 5. It forms an image in an annular shape.
  • FIG. 7 shows a lateral aberration diagram of the second optical path B of the optical system of this example.
  • the lateral aberration diagram of the first optical path A of the optical system of this example is the same as FIG.
  • the transmission surface and the reflection surface of the transparent medium L having a refractive index larger than 1 concentrically symmetric with respect to the central axis 2 of the optical system 1 are configured as spherical surfaces that are partially shared in the optical path. is there.
  • the optical system 1 includes a front group G f, a rear group G b, and an aperture S arranged coaxially with the central axis 2 between the front group G ⁇ and the rear group G b. After 1 group G b 1 and After 2 group G b 2
  • the front group G f consists of a front group cover glass C f whose refractive index is rotationally symmetric about the central axis 2 and greater than 1.
  • the front cover glass C f is composed of parallel flat plates, and the front group first transmission surface 1 1 and the front group second transmission surface 1 2 formed on the image side with respect to the front group first transmission surface 1 1. And have.
  • the rear group 1 G b 1 consists of a transparent medium L having a refractive index that is rotationally symmetric about the central axis 2 and greater than 1.
  • the transparent medium L is formed on the image side with respect to the rear group 1 first transmission surface 21 and the rear group 1 first transmission surface 21 on the central axis 2, and a part of the reflection medium 4 a
  • the rear first group first reflecting surface 2 2 having negative power and the rear first group first reflecting surface 2 2 are arranged on the opposite side of the image plane 5, and the reflecting coating 4 b is positive.
  • the rear first group second reflecting surface 2 3 having the following power and the rear first group second reflecting surface 2 3 disposed on the image plane 5 side from the rear first group second reflecting surface 2 3 and having the positive power. Further, it has a rear first group third transmission surface 25 formed on the image side with respect to the rear first group first transmission surface 21 and having a positive power.
  • the rear 2 group G b 2 is composed of the rear 2 group cover glass C b 2 having a rotationally symmetric refractive index greater than 1 around the central axis 2.
  • the rear 2nd group cover glass Cb2 is formed of a flat plate, and is formed on the image side with respect to the rear 2nd group first transmitting surface 3 1 and the rear 2nd group first transmitting surface 3 1. 2 transmissive surface 3 2.
  • the optical system 1 forms a first optical path A and a second optical path B.
  • the first optical path A the light beam incident from the object plane of the optical system 1 is divided into the front group first transmission surface 1 1, the front group second transmission surface 1 2, and the front group cover glass C f of the front group cover glass C f. It enters the transparent medium L via an opening S arranged coaxially with the central axis 2 between C ⁇ and the transparent medium L.
  • the transparent medium L In the transparent medium L, it enters after the first group 1st transmission surface 2 1, part of it is reflective coating 4 a, and part is totally reflected, and the back 1 group 1st reflection surface 2 2 is opposite to the image surface 5 Reflected by the first group 2nd reflecting surface 2 3 and reflected by the reflective coating 4b to the image surface 5 side, then passed through the first group 2nd transmitting surface 2 4 and exited from the transparent medium L. It has a letter-shaped optical path. After that, the rear second group cover glass Cb 2 passes through the rear second group first transmission surface 3 1 and the rear second group second transmission surface 3 2, and then circles at a predetermined radial position away from the central axis 2 of the image plane 5. An image is formed in a ring shape.
  • the rear 1st group 1st reflecting surface 2 2 is reflected to the opposite side of the image surface 5 and the other part is divided into two optical paths passing through the 1st group 3rd transmitting surface 25 and connected to the same position on the image surface 5. Imaged.
  • the light beam incident from the object surface of the optical system 1 is transmitted through the front group first transmission surface 1 1, front group second transmission surface 1 2, and front group cover.
  • the glass C f and the transparent medium L enter the transparent medium L through an opening S arranged coaxially with the central axis 2.
  • the transparent medium L has an optical path that passes through the rear group 1 and the first transparent surface 21 and exits from the transparent medium L through the rear group 1 and the third transparent surface 25. Then rear 2nd group cover glass Cb 2 rear 2nd group 1st transparent -
  • An image is formed on the central axis 2 of the image plane 5 through the oversurface 3 1 and the rear second group second transmission surface 3 2.
  • Example 2-2 The specifications of Example 2-2 are as follows:
  • FIG. 9 shows a lateral aberration diagram of the entire optical system of this example.
  • the transmission surface and the reflection surface of the transparent medium L having a refractive index larger than 1 concentrically symmetric with respect to the central axis 2 of the optical system 1 are configured as a spherical surface that is partially shared in the optical path, and
  • a front lens group L f and a rear second lens group L b 2 are arranged before and after the transparent medium L.
  • the optical system 1 includes a front group G f, a rear group G b, and an aperture S arranged coaxially with the central axis 2 between the front group G f and the rear group G b.
  • the rear group G b It consists of the first group G b 1 and the second group G b 2.
  • the front group G f consists of a front group lens L f with a refractive index greater than 1 which is rotationally symmetric about the central axis 2.
  • the front lens group L f is composed of a negative meniscus lens with a convex surface facing the object side, and is arranged on the front group first transmission surface 1 1 and front group first transmission surface 1 1.
  • it has a front group second transmission surface 1 2 formed on the image side.
  • the rear group 1 G b 1 consists of a transparent medium L having a refractive index that is rotationally symmetric about the central axis 2 and greater than 1.
  • the transparent medium L is formed on the image side with respect to the rear group 1 first transmission surface 21 and the rear group 1 first transmission surface 21 on the central axis 2, and a part of the reflection medium 4 a
  • the rear first group first reflecting surface 2 2 having negative power and the rear first group first reflecting surface 2 2 are arranged on the side opposite to the image plane 5, and a part of the reflecting coating 4 b is provided.
  • Rear 1st group 2nd reflecting surface 2 3 with positive power and rear 1st group 2nd reflecting surface 2 3 are arranged on the image plane 5 side from the rear 1st group 2nd reflecting surface 2 3 and have rear 1st group 2nd transmitting surface 2 4 with positive power .
  • Rear 1st group 1st transmission surface 2 1 and rear 1st group 2nd reflection surface 2 3 have the same position and the same shape
  • Rear 1st group 1st reflection surface 2 2 and rear 1st group 2nd transmission surface 2 4 are the same It consists of the same shape.
  • the rear second group G b 2 is composed of the rear second group lens L b 2 having a rotationally symmetric refractive index greater than 1 around the central axis 2.
  • the rear second group lens L b 2 is a plano-concave lens having a concave surface facing the object side, and is formed on the image side with respect to the rear second group first transmission surface 3 1 and the rear second group first transmission surface 3 1.
  • the optical system 1 forms the optical path A.
  • the light beam incident from the object plane of the optical system 1 is the front group first transmission surface 1 1 and front group second transmission surface 1 2 of the front group lens L f, the front group lens L f and the transparent medium L.
  • the transparent medium L it enters through the first group 1 and the first transmission surface 2 1, and the rear group 1 and the first reflection surface 2 2 are partially reflective coating 4 a and partly opposite to the image surface 5 due to total reflection.
  • Example 3-1 The specifications of Example 3-1 are as follows:
  • FIG. 11 shows a lateral aberration diagram of the second optical path of the optical system of this example.
  • the lateral aberration diagram of the first optical path in the optical system of this example is the same as FIG.
  • the transmission surface and the reflection surface of the transparent medium L having a refractive index larger than 1 concentrically symmetric with respect to the central axis 2 of the optical system 1 are configured as spherical surfaces that are partially shared in the optical path. is there.
  • the optical system 1 includes a front group G i, a rear group G b, and an aperture S arranged coaxially with the central axis 2 between the front group G ⁇ and the rear group G b, and the rear group G b It consists of rear 1 group G b 1 and rear 2 group G b 2.
  • the front group G f is composed of a front group lens f having a refractive index which is rotationally symmetric about the central axis 2 and greater than 1.
  • the front lens group L f is composed of a negative meniscus lens having a convex surface directed toward the object side.
  • the front lens group L f is formed on the image side with respect to the front group first transmission surface 11 and the front group first transmission surface 11. 2 transmissive surface 1 2.
  • the rear group 1 G b 1 consists of a transparent medium L having a refractive index that is rotationally symmetric about the central axis 2 and greater than 1.
  • Transparent medium L consists of a spherical surface on center axis 2 1st transmission surface 2 1 and rear 1st group 1st transmission surface 2 1 formed on the image side with respect to the rear 1st group 1st reflection surface 2 2
  • the rear first group second reflecting surface 2 3 which is disposed on the opposite side to the image surface 5 with respect to the rear first group first reflecting surface 2 2, partially reflectively coated 4 b, and has a positive power
  • the rear first group second reflecting surface 2 3 is disposed on the image plane 5 'side and has a rear first group second transmitting surface 24 having positive power. Further, it has a rear first group third transmission surface 25 formed on the image side with respect to the rear first group first transmission surface 21 and having a positive power.
  • the rear second group G b 2 is composed of the rear second group lens L b 2 having a rotationally symmetric refractive index greater than 1 around the central axis 2.
  • the rear second group lens L b 2 is composed of a plano-concave lens having a concave surface facing the object side, and is formed on the image side with respect to the rear second group first transmission surface 3 1 and the rear second group first transmission surface 3 1.
  • the optical system 1 forms a first optical path A and a second optical path B.
  • the light beam incident from the object plane of the optical system 1 is the front group first transmission surface 1 1, front group second transmission surface 1 2, front group lens L f, and front group lens L f.
  • the transparent medium L enters the transparent medium L through the opening S arranged coaxially with the central axis 2 between the transparent media L.
  • the rear first group first reflecting surface 2 2 and the image surface 5 Reflected to the opposite side, reflected back to the image surface 5 side by the reflective coating 4b at the rear 1st group 2nd reflecting surface 2 3 and then exited from the transparent medium L via the rear 1st group 2nd transmitting surface 2 4 It has a Z-shaped optical path.
  • the rear second group lens L b 2 passes through the rear second group first transmission surface 3 1 and the rear second group second transmission surface 3, and then annulars at a predetermined radial position away from the central axis 2 of the image surface 5. To form an image.
  • part of the optical path through which the central principal ray passes through the boundary between the rear group 1 first reflecting surface 22 and the rear group 1 third transmitting surface 25 is due to reflection coating.
  • Rear 1st group 1st reflecting surface 2 2 is reflected to the opposite side of image plane 5
  • the light beam is divided into two light paths passing through the third transmission surface 25 and imaged at the same position on the image surface 5.
  • the light beam incident from the object plane of the optical system 1 is transmitted through the front group first transmission surface 11 and front group second transmission surface 1 2 of the front group lens L f, and the front group lens L
  • the light enters the transparent medium L through the opening S arranged coaxially with the central axis 2 between f and the transparent medium L.
  • the transparent medium L has an optical path that passes through the first group first transmitting surface 21 after the first group and exits from the transparent medium L through the third group third transmitting surface 25 after the first group. Thereafter, an image is formed on the central axis 2 of the image plane 5 through the rear second group first transmission surface 3 1 and the rear second group first transmission surface 3 2 of the rear second group lens L b 2.
  • Example 3-2 The specifications of Example 3-2 are as follows:
  • FIG. 4 A cross-sectional view taken along the central axis 2 of the optical system 1 of Example 4 is shown in FIG. Also, the lateral aberration diagram of the second optical path of the optical system of this example is not shown in FIG.
  • the transmission surface and the reflection surface of the transparent medium L having a refractive index larger than 1 concentrically symmetric with respect to the central axis 2 of the optical system 1 are configured as spherical surfaces that are partially shared in the optical path. is there.
  • the optical system 1 includes a front group G f, a rear group G b, and an aperture S arranged coaxially with the central axis 2 between the front group G f and the rear group G b.
  • the rear group G b It consists of rear 1 group G b 1 and rear 2 group G b 2.
  • the front group G f consists of a front group cover glass C f whose refractive index is rotationally symmetric about the central axis 2 and greater than 1.
  • the front cover glass C f is composed of parallel flat plates, and the front group first transmission surface 1 1 and the front group second transmission surface 1 2 formed on the image side with respect to the front group first transmission surface 1 1. And have.
  • the rear group 1 G b 1 consists of a transparent medium L having a refractive index that is rotationally symmetric about the central axis 2 and greater than 1.
  • the transparent medium L is composed of a cemented lens having a birefringent positive lens L a as the rear first group first transparent medium and a biconcave positive lens L b as the rear first group second transparent medium having different refractive indexes, and is centered.
  • a rear group 1 first transmission surface 2 1 made of a spherical surface on axis 2 and a part of the transparent medium L are coated with reflection coating 4 a, and are formed on the image side with respect to the rear group 1 first transmission surface 2 1.
  • the first group 1st reflecting surface 2 2 having negative power and the transparent medium L are reflected and coated 4b, and the rear 1 group 1st reflecting surface 2 2 is disposed on the opposite side of the image plane 5;
  • Rear 1st group 1st transmission surface 2 1 and Rear 1st group 2nd reflection surface 2 3 have the same position and shape.
  • Rear 1st group 1st reflection surface 2 2 and Rear 1st group 2nd transmission surface 2 4 It consists of the same shape at the same position.
  • the rear 2 group G b 2 is composed of the rear 2 group cover glass C b 2 having a rotationally symmetric refractive index greater than 1 around the central axis 2.
  • the rear 2nd group cover glass Cb2 is formed of a flat plate, and is formed on the image side with respect to the rear 2nd group first transmitting surface 3 1 and the rear 2nd group first transmitting surface 3 1. 2 transmissive surface 3 1. [0 0 9 9]
  • the optical system 1 forms the optical path A.
  • the light beam incident from the object plane of the optical system 1 is divided into the front group first transmission surface 1 1, front group second transmission surface 1 2 and front group cover one glass C f of the front group cover glass C f.
  • the transparent medium L it enters after the first group first transmitting surface 2 1, passes through the refracting surface 20 ab, and partly reflects coating 4 a and partly on the rear group 1 first reflecting surface 2 2.
  • the rear 2nd group cover glass Cb 2 passes through the rear 2nd group 1st transmission surface 3 1 and the rear 2nd group 2nd transmission surface 3 2, and then circles at a predetermined radial position away from the central axis 2 of the image plane 5.
  • An image is formed in a ring shape.
  • the maximum image height is I max (mm)
  • the minimum image height is I min ( ⁇ )
  • the maximum field angle of the rear group G r is 0 max (degrees)
  • the minimum field angle of the rear group G r is 0 min ( Degree)
  • focal length F (mm) (I max-I min) / ( ⁇ max- ⁇ min)
  • rear group G r outer diameter D (mm) rear group excluding parallel flat protective glass
  • the curvature of the rear group first reflective surface 2 2 is 1
  • the curvature of the rear group second reflective surface 2 3 is R 2
  • Example 1 Example 2
  • Example 3 Example 4 I max 1.00 0.95 1.00 0.99 ⁇ max 60.00 60.00 66.76 60.00
  • FIG. 14 shows an arrangement example of the image and the image sensor of this embodiment.
  • Figure 14 (a) is an example using an image sensor with a screen ratio of 16: 9.
  • Fig. 14 (b) is an example in which an image sensor 50 having a screen ratio of 4: 3 is used, and the size of the image sensor 50 is matched with the image B 1 in the second optical path B.
  • Fig. 1 4 As in (a), the vertical image is not used.
  • FIG. 14 (c) is an example in which an image sensor 50 having a screen ratio of 4: 3 is used, and the size of the image sensor 50 is matched with the image A 1 in the first optical path A. In this way, if the arrangement is made, both the image A 1 of the first optical path A and the image B 1 of the second optical path B can be captured.
  • FIG. 15 is a diagram for illustrating an example in which the photographing optical system 10 1 according to the present invention is used as a photographing optical system at the distal end of the endoscope.
  • FIG. 15 (a) shows a rigid endoscope 110. This is an example in which an imaging optical system according to the present invention is attached to the tip 110 a of the camera and an image is taken and observed.
  • Figure 15 (b) shows the schematic configuration of the tip.
  • FIG. 15 (c) shows an image captured on the display device 1 1 4 by attaching the panoramic imaging optical system 1 0 1 according to the present invention to the tip of the flexible electronic endoscope 1 1 3 in the same manner. This is an example in which image processing is performed to correct distortion and display.
  • FIG. 16 shows an example in which a photographic optical system 10 1 according to the present invention is attached to a capsule endoscope 120 and images of 360 ° omnidirectional images are taken and observed.
  • a flare stop 1 0 7 is provided for a casing having an opening 10 6 extending in the circumferential direction in front of the first transmission surface 1 1 of the front group G f of the imaging optical system 1 0 1 according to the present invention. This prevents flare light from entering.
  • the photographing optical system 10 1 for the endoscope by using the photographing optical system 10 1 for the endoscope, the image behind the photographing optical system 100 1 can be imaged and observed from a different angle from the conventional angle. Various parts can be imaged and observed.
  • Fig. 17 (a) shows an image taken through each imaging optical system 1 0 1 on a display device in a car with the imaging optical system 1 0 1 according to the present invention attached as an imaging optical system in front of the automobile 1 3 0.
  • Fig. 17 (b) shows an example in which the processed image is subjected to image processing to correct distortion and displayed at the same time.
  • the present invention as a photographic optical system at the top of An example in which multiple photographic optical systems 1 0 1 are installed and images taken through each photographic optical system 1 0 1 on a display device in a car is subjected to image processing to correct distortion and simultaneously displayed FIG.
  • FIG. 17 (a) ⁇ it is preferable that the left and right images can be captured widely by matching the size of the image sensor 50 with the left and right positions of the image A 1 in the first optical path A. .
  • the projection optical system 100 is used as the projection optical system of the projection apparatus 140, and a panoramic image is displayed on the display element arranged on the image plane 5.
  • a 360 ° omnidirectional image is projected and displayed on a screen 1 4 1 arranged in 360 ° omnidirectional through 0-2.
  • FIG. 19 shows a projection apparatus using the photographing optical system 1 0 1 according to the present invention indoors, with the photographing apparatus 15 1 using the photographing optical system 1 0 1 according to the present invention attached to the outside of the building 1 5 0. 1 5 1 is arranged and connected so that the image captured by the imaging device 1 51 is sent to the projection device 1 4 0 via the electric wire 15 2.
  • an outdoor 360 ° omnidirectional subject P is photographed by the photographing device 1 5 1 through the photographing optical system 1 0 1, and the video signal is projected through the electric wire 15 2.
  • optical system of the present invention it is possible to obtain a compact optical system with good resolving power with good aberration correction that can observe a wide angle of view or project an image with a wide angle of view with a simple configuration. it can.

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Abstract

L'invention concerne un système optique et un endoscope comprenant ce système. Ce système comporte une première surface transmissive (21), une seconde surface réfléchissante (22) et une seconde surface transmissive (24) qui sont toutes des surfaces sphériques. Un flux lumineux entrant dans un matériau transparent (L) forme un premier chemin optique (A) présentant sensiblement une forme de Z, le faisceau se propageant selon la trajectoire suivante: il pénètre dans le matériau transparent (L) à travers une ouverture (S) et la première surface transmissive (21), est réfléchi du côté opposé à une surface de formation d'image par la première surface réfléchissante (22), puis est réfléchi du côté de la surface de formation d'image par la seconde surface réfléchissante (23), et sort enfin du matériau transparent (L) du côté de la surface de formation d'image à travers la seconde surface transmissive (24). Au moins une partie du chemin optique (A), comprise entre la première surface réfléchissante (22) et la seconde surface réfléchissante (23), se forme d'un seul côté d'un axe central (2). Une image de forme annulaire est créée sur la surface de formation d'image (5) sans qu'une image intermédiaire ne soit formée dans le premier chemin optique (A).
PCT/JP2008/066504 2007-09-27 2008-09-08 Système optique et endoscope comprenant ce système Ceased WO2009041290A1 (fr)

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JP2007-251101 2007-09-27
JP2007251101A JP2009080411A (ja) 2007-09-27 2007-09-27 光学系及びそれを用いた内視鏡

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JP7005207B2 (ja) * 2017-07-26 2022-01-21 キヤノン株式会社 光学系、それを備える撮像装置及び投影装置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04274406A (ja) * 1990-12-13 1992-09-30 Hughes Aircraft Co 画像センサの同時二重視野
JP2004361777A (ja) * 2003-06-06 2004-12-24 Nikon Corp ソリッド型カタディオプトリック光学系

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04274406A (ja) * 1990-12-13 1992-09-30 Hughes Aircraft Co 画像センサの同時二重視野
JP2004361777A (ja) * 2003-06-06 2004-12-24 Nikon Corp ソリッド型カタディオプトリック光学系

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