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WO2013114725A1 - Optical system for stereo-endoscope - Google Patents

Optical system for stereo-endoscope Download PDF

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Publication number
WO2013114725A1
WO2013114725A1 PCT/JP2012/081575 JP2012081575W WO2013114725A1 WO 2013114725 A1 WO2013114725 A1 WO 2013114725A1 JP 2012081575 W JP2012081575 W JP 2012081575W WO 2013114725 A1 WO2013114725 A1 WO 2013114725A1
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WIPO (PCT)
Prior art keywords
positive lens
pair
lens group
optical system
lens groups
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PCT/JP2012/081575
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French (fr)
Japanese (ja)
Inventor
浪井　泰志
福島　郁俊
光次郎 金野
Original Assignee
オリンパスメディカルシステムズ株式会社
オリンパス株式会社
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Application filed by オリンパスメディカルシステムズ株式会社, オリンパス株式会社 filed Critical オリンパスメディカルシステムズ株式会社
Publication of WO2013114725A1 publication Critical patent/WO2013114725A1/en

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    • 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
    • A61B1/00163—Optical arrangements
    • A61B1/00193—Optical arrangements adapted for stereoscopic vision
    • 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
    • G02B23/2415—Stereoscopic endoscopes

Definitions

  • the present invention relates to a stereoscopic endoscope optical system.
  • a stereoscopic endoscope including an optical system that forms two images having parallax on substantially the same plane is known (see, for example, Patent Document 1 and Patent Document 2).
  • the optical system of Patent Document 1 includes a pair of first group lenses having negative power and an array of second group lenses having two positive powers arranged in order from the object side.
  • the optical system of Patent Document 2 includes two sets of first group lenses having negative power arranged in order from the object side, and one set of second group lenses having positive power.
  • optical systems are arranged so that the optical axis of the first group lens and the optical axis of the second group lens are decentered, so that two light beams incident from the subject to the first group lens with a left-right spacing. While passing through the first group lens and the second group lens, the interval between these two light beams is deflected to form an image on the image pickup surface of the image pickup device that is also arranged side by side.
  • the present invention provides the following means. Aspects of the present invention include a pair of negative lens groups arranged at the distal end of an insertion portion of an endoscope and arranged in order from the object side with respective optical axes spaced from each other on the left and right sides, and the negative lenses. A pair of first positive lens groups disposed coaxially behind the group, a second positive lens group disposed eccentrically with respect to the first positive lens group, and a pair of the first lenses A pair of lens elements disposed between the first positive lens group and the second positive lens group, and deflects the light transmitted through the first positive lens group and makes it incident on the second positive lens group. This is a stereoscopic endoscope optical system including the optical axis deflection member.
  • the two light beams from the object are diverged by the negative lens group and converged by the first positive lens group, and then deflected by the optical axis deflecting member, so that the distance between the two light beams is increased.
  • the light beam is incident on the optical axis of the second positive lens unit arranged eccentrically with respect to the first positive lens unit.
  • the second positive beam can be simply passed through the optical axis deflecting member without sufficiently securing the dimension in the optical axis direction as in the case where the distance between the two light beams is adjusted only by the eccentricity of the lens.
  • the interval between the light beams can be adjusted according to the position of the lens group. Further, by arranging the optical axis deflecting member downstream of the negative lens group and the positive lens group with respect to the object, light in a substantially parallel light beam is incident on the optical axis deflecting member, and aberrations in the optical axis deflecting member Can be suppressed. Therefore, it is possible to shorten the dimension in the optical axis direction and improve the optical performance.
  • the optical axis deflecting member may be a transmissive prism that deflects light transmitted through the first positive lens group twice and enters the second positive lens group. Good. With this configuration, it is not necessary to adjust the position between the reflecting surfaces of the mirrors as in the case of deflecting light by the reflection of a plurality of mirrors, and the occurrence of image tilt can be prevented.
  • the optical axis deflecting member may be configured by at least one reflecting surface.
  • the light transmitted through the first positive lens group is deflected by being reflected by the reflecting surface, and is decentered with respect to the first positive lens group. Incident to the positive lens group. Therefore, when the optical axis of the first positive lens group and the optical axis of the second positive lens group are not parallel, the light from the first positive lens is adjusted by adjusting the angle of the reflecting surface. To be incident near the center of the optical axis of the second positive lens group.
  • a pair of the second positive lens group may be provided corresponding to the pair of the first positive lens groups.
  • the pair of lenses constituting the pair of second positive lens groups may be integrally formed. With this configuration, the lens can be easily manufactured by sharing the lens pair constituting the second positive lens group.
  • the pair of second positive lens groups may be arranged in a direction orthogonal to the arrangement direction of the pair of first positive lens groups.
  • the left and right lens pairs constituting the pair of negative lens groups and the pair of first positive lens groups may be integrally formed.
  • a cylindrical light shielding member that shields light from the pair of negative lens groups and the pair of first positive lens groups over the entire circumference may be provided. With this configuration, stray light can be reduced.
  • a pupil position may be disposed inside the optical axis deflection member.
  • FIG. 1 is a schematic configuration diagram illustrating a stereoscopic endoscope optical system according to a first embodiment of the present invention. It is a lens block diagram of the stereoscopic endoscope optical system of FIG. It is the schematic block diagram which looked at the stereoscopic endoscope optical system which concerns on 2nd Embodiment of this invention from the direction orthogonal to the parallel direction of a negative lens group. It is the schematic block diagram which looked at FIG. 3 from the direction orthogonal to the parallel direction of a negative lens group.
  • FIG. 4 is a perspective view of the stereoscopic endoscope optical system of FIG. 3.
  • FIG. 4 is a perspective view of the stereoscopic endoscope optical system of FIG. 3 as viewed in the axial direction from the object side.
  • FIG. 12 It is a lens block diagram of the stereoscopic endoscope optical system of FIG. It is the schematic block diagram which looked at the stereoscopic endoscope optical system which concerns on the modification of 2nd Embodiment of this invention from the direction orthogonal to the parallel direction of a negative lens group. It is the schematic block diagram which looked at FIG. 12 from the direction orthogonal to the parallel direction of a negative lens group. It is a perspective view of the stereoscopic endoscope optical system of FIG. FIG. 13 is a perspective view of the stereoscopic endoscope optical system of FIG. 12 as viewed in the axial direction from the object side. It is the perspective view which looked at the stereoscopic endoscope optical system of FIG.
  • the stereoscopic endoscope optical system 100 can be disposed at the distal end of the insertion portion of the endoscope.
  • the stereoscopic endoscope optical system 100 includes a pair of negative lens groups 10 arranged in order from the object side, and a pair into which light transmitted through the negative lens group 10 is incident.
  • the first positive lens group 20, the prism pair (optical axis deflecting member) 30 that deflects the light transmitted through the first positive lens group 20, and the light deflected by the prism pair 30 is incident thereon.
  • 2 positive lens groups 40 are examples of the prism pair.
  • the pair of negative lens groups 10 includes a pair of left and right lenses 11 that are integrally molded, and has a common optical path.
  • the optical axes of the lens pair 11 are respectively arranged with a space left and right.
  • the pair of negative lens groups 10 has a negative refractive power. Thereby, the pair of negative lens groups 10 can collect light emitted from a wide range of subjects arranged on the object side.
  • the first positive lens group 20 includes two lens pairs 21 and 23 arranged in the axial direction. These lens pairs 21 and 23 are disposed coaxially with the lens pair 11 of the pair of negative lens groups 10 and are integrally molded.
  • the first positive lens group 20 has a positive refractive power for converging light.
  • the left and right lens pairs 11 and 21 and the left and right lens pairs 21 and 23 constituting the pair of first positive lens groups 20 are integrally molded, respectively. It is possible to further reduce the dimension in the optical axis direction by intersecting the light rays forming two images having parallax.
  • the prism pair 30 deflects and transmits the light from the first positive lens group 20 twice and makes it incident on the second positive lens group 40.
  • the prism pair 30 is composed of, for example, two parallelogram prisms 31 made of parallelepipeds.
  • the prisms 31 are arranged along the parallel direction of the lens pair 11 constituting the negative lens group 10. These prisms 31 have an entrance surface 31a and an exit surface 31b that are parallel to each other. The entrance surface 31a and the exit surface 31b of each prism 31 are arranged so as to widen the distance between the optical axes of the light beams emitted from the pair of first positive lens groups 20.
  • the prism 31 deflects the light beam formed by the first positive lens group 20 in the direction of widening the interval between the optical axes when entering from the incident surface 31a, and emits the light beam on the output surface 31b. At this time, the optical axis is deflected in a direction to make it parallel.
  • the optical axis of the first positive lens group 20 and the optical axis of the second positive lens group 40 coincide with each other. .
  • the two light beams that have passed through the pair of first positive lens groups 10 pass through the pair of prism pairs 30 to enlarge only the interval between the optical axes without changing the parallel direction thereof. And is incident on the second positive lens group 20.
  • the second positive lens group 40 is provided as a pair corresponding to the pair of first positive lens groups 20, and is configured by an integrally molded lens pair 41.
  • the second positive lens group 40 is arranged eccentrically with respect to the first positive lens group 20 and has a positive refractive power for converging the light deflected by the prism 31.
  • the light beam emitted from the second positive lens group 40 is incident on the image pickup surface 51a of the image pickup device 50 such as a CCD arranged at the subsequent stage.
  • FIG. 2 shows a lens configuration of the stereoscopic endoscope optical system 100 according to the present embodiment, and lens data is shown below.
  • the stereoscopic endoscope optical system 100 has, for example, an object distance of 20 mm, a focal length of 0.6187 mm, an F value of 4.2, an imaging area (one side) of 0.6 mm ⁇ 0.8 mm, a negative lens group
  • the lens interval of 10 is 0.7 mm
  • the imaging interval of the left and right images is 1.0 mm.
  • a symbol Ln indicates a surface interval of the surface number n. The same applies to FIGS.
  • Lens data surface number Radius Distance Refractive index Dispersion 0 ⁇ 0.24 1.88815 40.7645 1 0.391285 0.18 2 4.44471 0.18 1.88815 40.7645 3 0.84 0.36 1.58565 46.4224 4 -1.08018 0.12 5 -6.86009 0.42 1.51825 64.1411 6 -0.64267 0.18 7 ⁇ 0.72 1.51564 75.009 8 ⁇ 0.268192 9 0.97587 0.78 1.57124 56.363 10 -0.79221 0.29474 1.93429 18.8966 11 -4.1074 0.601262 The inclination angles of the surfaces r7 and r8 constituting the prism 31 are 32.5 °.
  • the stereoscopic endoscope optical system 100 configured as described above will be described.
  • light emitted from a subject is incident on a pair of negative lens groups 10 having an optical axis spaced apart from each other.
  • the light is diverged and emitted as a substantially parallel light beam having parallax.
  • the luminous flux emitted from the negative lens group 10 is incident on and converged on the first positive lens group 20 disposed in the subsequent stage.
  • the light beam that has passed through the first positive lens group 20 is incident on the incident surface 31 of the prism 31 that constitutes the prism pair 30.
  • the light beam that has entered the prism pair 30 is deflected in a direction in which the interval between the optical axes is widened on the incident surface 31a, and then is deflected in the direction in which the interval between the optical axes is paralleled on the exit surface 31b.
  • the two light beams incident on the pair of prisms 30 pass through the prism pair 30 with only the interval between the optical axes enlarged without changing the parallel direction of the first positive lens.
  • the light beams are incident on the optical axis of the second positive lens group 40 arranged eccentrically with respect to the group 20.
  • the light beams incident on the second positive lens group 40 are converged and emitted, and enter the imaging surface 51a of the imaging device 50. Thereby, two images having parallax are formed on the same imaging surface 51 a of the imaging element 50.
  • the light is deflected by the prism pair 30 so that the interval between the two light beams is adjusted only by the eccentricity of the deflection lens. Even if the dimension in the optical axis direction is not sufficiently secured, the interval between the light beams can be adjusted according to the position of the second positive lens group 40.
  • the prism pair 30 by arranging the prism pair 30 at the subsequent stage of the negative lens group 10 and the first positive lens group 20 with respect to the object, light of a substantially parallel light beam is incident on the prism pair 30, and the prism pair 30. Occurrence of aberrations can be suppressed. Thereby, the optical performance can be improved and the dimension in the optical axis direction can be shortened.
  • the stereoscopic endoscope optical system 200 according to the second embodiment of the present invention has one each for reflecting and deflecting light instead of the prism pair 30 as an optical axis deflecting member.
  • a pair of second positive lens groups 40 is employed, in which a prismatic prism 130 having two reflective surfaces 131a and 131b parallel to each other is adopted.
  • the second embodiment differs from the first embodiment in that it includes a pair of second positive lens groups 140 arranged in a direction orthogonal to the arrangement direction of the first positive lens group 120.
  • portions having the same configuration as those of the stereoscopic endoscope optical system 100 according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.
  • the pair of negative lens groups 110 includes two lens pairs 13 and 15 arranged in the axial direction, and these lens pairs 13 and 15 are arranged in parallel at an interval in one direction.
  • the first positive lens group 120 includes two lens pairs 25 and 27 arranged in the axial direction. These lens pairs 25 and 27 are provided at intervals in one direction, and are arranged coaxially with the lens pairs 13 and 15 of the pair of negative lens groups 110, respectively.
  • the second positive lens group 140 includes a lens pair 43 having a positive refractive power and arranged in parallel in a direction orthogonal to the parallel direction of the lens pairs 25 and 27 constituting the first positive lens group 120. 35.
  • the light beam emitted from the second positive lens group 140 is directly incident on the image pickup surface 51a of the image pickup element 50 arranged at the subsequent stage.
  • the pair of second positive lens groups 140 are formed in a cross-sectional shape that is long in the parallel direction of the lens pairs 25 and 27 of the pair of first positive lens groups 120 and short in the direction perpendicular thereto.
  • the luminous flux is incident on the imaging surface 51 a side by side in a direction orthogonal to the parallel direction of the lens pairs 25 and 27 of the first positive lens group 120.
  • the prism mirror pair 130 reflects the light from the first positive lens group 120 twice and makes it incident on the second positive lens group 140.
  • the prism mirror pair 130 includes two mirrors 131 having two reflecting surfaces 131a and 131b arranged in parallel to each other.
  • the prism mirror pair 130 is disposed at an angle of 22.2 ° with respect to the arrangement direction of the first positive lens group 120.
  • the mirror 131 viewed from the direction of arrow A shown in FIGS. 6 and 7 is shown in FIG. 9A.
  • 9A shows a state where the mirror 131 of FIG. 9A is viewed in the arrow B direction (direction in which the mirrors 131 overlap)
  • FIG. 9C shows a state where the mirror 131 of FIG. 9A is viewed from the image sensor 50 side.
  • the reflecting surfaces 131a of the mirrors 131 are provided so as to be inclined and opposed to the pair of first positive lens groups 120, respectively, and positions corresponding to the optical axes of the first positive lens groups 110, respectively.
  • the center position is arranged.
  • the reflecting surface 131b of each mirror 131 is provided so as to be inclined and opposed to the pair of second positive lens groups 140, and coincides with the optical axis of each second positive lens group 140.
  • the center position is arranged at the position to be.
  • the pair of prism mirrors 130 is arranged in parallel at the center position in the direction orthogonal to the parallel direction of the lens pairs 25 and 27 constituting each first positive lens group 120.
  • the light beam is converted so that the parallel direction of the optical axes of the first positive lens group 120 is rotated by 90 °.
  • the prism mirror pair 130 has a diaphragm 33 as shown in FIG. 10 at the joint between the mirrors 131, and the pupil position is arranged inside. Thereby, the light can be collected inside the prism mirror pair 130 and the axial dimension of the prism mirror pair 130 can be reduced.
  • the diaphragm 33 has, for example, a diameter of 0.36 mm. 9A, 9 ⁇ / b> C, and 10, reference numeral 131 c indicates a joint portion between the mirrors 131.
  • FIG. 11 shows a lens configuration of the stereoscopic endoscope optical system 200 according to the present embodiment, and lens data is shown below.
  • the stereoscopic endoscope optical system 200 has, for example, an object distance of 36 mm, a focal length of 1.1 mm, an F value of 6.2, an imaging area (one side) of 0.9 mm ⁇ 0.68 mm, a negative lens group
  • the lens interval of 10 is 2.0 mm, and the imaging interval of the left and right images is 0.8312 mm.
  • the prism mirror pair 130 includes the two reflecting surfaces 131a and 131b manufactured in parallel with high accuracy, so that the pair of negative electrodes is emitted from the subject.
  • the light beams transmitted through the lens group 110 and the pair of first positive lens groups 120 are reflected twice by the two reflecting surfaces 131a and 131b in the mirror 131 and are incident on the pair of second positive lens groups 140. .
  • each pair of prism mirrors 130 is disposed at an angle of 22.2 ° with respect to the arrangement direction of the first positive lens group 120, and the reflection surface 131b thereof is parallel to the reflection surface 131a. Since the two light beams emitted from the respective reflecting surfaces 131b are rotated by 90 ° in the parallel direction when entering the two reflecting surfaces 131a. Then, the two light beams reflected by the reflecting surface 131 b of the mirror 131 are incident on the pair of second positive lens groups 140, converged by the positive refractive power, and incident on the image sensor 50. Thereby, two images having parallax are formed on the same imaging surface 51 a of the imaging element 50.
  • two light beams having a parallax emitted from the same subject and spaced in parallel in one direction are arranged in the parallel direction.
  • Stereo imaging can be performed by making two light beams arranged in orthogonal directions incident on the imaging surface. Accordingly, since two light beams formed in a cross-sectional shape that is long in the direction parallel to the first positive lens group 120 and short in the direction perpendicular thereto are imaged in two steps in the short side direction, the parallax is reduced. Even if it is relatively large, the center position of image formation can be brought close to with high precision. Further, the image pickup device 50 can be effectively used by forming two light beams in two rows in the short side direction.
  • the stereoscopic endoscope optical system 200 includes the second positive lens group 140 configured by the lens pairs 43 and 45 that are arranged in parallel at an interval in one direction.
  • a second positive lens group 141 composed of a pair of lenses 47 and 49 integrally molded may be provided. Good. In this way, the lens can be easily manufactured by sharing the lens pairs 47 and 49 constituting the second positive lens group 141.
  • the prism mirror pair 130 is disposed at an angle of 30 ° with respect to the arrangement direction of the first positive lens group 120.
  • the distance between the optical axes of the lens pair 15 is 2.0 mm.
  • the mirror 131 viewed from the direction of arrow C shown in FIG. 15 is shown in FIG. 18A.
  • 18B shows the mirror 131 viewed in the direction of arrow D in FIG. 18A.
  • the reflection surface 131b of the mirror 131 is disposed at an angle of 1.845 ° with respect to the reflection surface 131a, for example.
  • the diaphragm 33 has a diameter of 0.84 mm.
  • FIG. 20 shows a lens configuration of the stereoscopic endoscope optical system 200 according to this modification, and lens data is shown below.
  • This stereoscopic endoscope optical system 200 has, for example, an object distance of 100 mm, a focal length of 1.5225 mm, an F value of 4.78, an imaging area (one side) of 0.6 mm ⁇ 0.8 mm, a negative lens group
  • the lens interval of 110 is 2.0 mm, and the imaging interval of the left and right images is 0.6 mm.
  • the stereoscopic endoscope optical system 300 according to the third embodiment of the present invention employs a mirror pair 230 having at least one reflecting surface 231a that reflects and deflects light as an optical axis deflecting member.
  • the same reference numerals are given to portions having the same configurations as those of the stereoscopic endoscope optical system 100 according to the first embodiment and the stereoscopic endoscope optical system 200 according to the second embodiment, and description thereof is omitted. .
  • the pair of second positive lens groups 141 are arranged so that the optical axes thereof intersect the optical axes of the pair of first positive lens groups 120.
  • the optical axes of the pair of second positive lens groups 241 are arranged so as to be substantially orthogonal to the optical axes of the pair of first positive lens groups 120.
  • the mirror pair 230 is composed of mirrors 231 each having a reflecting surface 231a.
  • the mirrors 231 are arranged in parallel with each other on the optical axis of the pair of first positive lens groups 120.
  • each mirror 231 is arranged with an angle shifted in the arrangement direction of the pair of second positive lens groups 241 while the reflecting surfaces 231a are inclined in the direction facing each other.
  • the mirror pair 230 reflects and deflects the light transmitted through the pair of first positive lens groups 120 in a direction substantially orthogonal to the reflecting surface 231a, and the optical axis of the second positive lens group 241 is reflected. It can be incident near the center. Then, through the second positive lens group 241, the two light beams are converted so as to be rotated by 90 ° with respect to the parallel direction of the optical axes of the first positive lens group 120, and the imaging surface of the imaging device 50 is converted. It can be made incident on 51a.
  • the optical axis of the first positive lens group 120 and the optical axis of the second positive lens group 241 are not parallel.
  • the angle of the reflecting surface 231a is adjusted to deflect two light beams having a parallax that are emitted from the same subject and spaced in parallel in one direction so that the second positive lens group 241
  • Stereo imaging is performed by making the light incident near the center of the optical axis and entering the imaging surface 51a as two light beams in which the optical axes are arranged in a direction orthogonal to the parallel direction of the optical axis of the first positive imaging element 120. it can.
  • the embodiment of the present invention has been described in detail with reference to the drawings.
  • the specific configuration is not limited to this embodiment, and includes design changes and the like within a scope not departing from the gist of the present invention.
  • the present invention is not limited to those applied to each of the above embodiments, and may be applied to embodiments in which these embodiments are appropriately combined, and is not particularly limited.
  • the stereoscopic endoscope optical system 100, 200, 300 includes the pair of negative lens groups 10, 110 and the pair of first positive lens groups 20, 120 over the entire circumference. It is good also as providing the cylindrical light-shielding member which light-shields. By doing so, stray light can be reduced.

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Abstract

In order to shorten the dimension along the optical axis while enhancing optical performance, an optical system (100) for a stereo-endoscope is provided with, in order from the object side and disposed at the distal end of an insertion part of an endoscope,: a pair of negative lens groups (10), the optical axes of which are spaced apart to the left and right; a pair of first positive lens groups (20) disposed on the same axis at a stage subsequent to the negative lens groups (10); a second positive lens group (40) disposed eccentrically from the first positive lens group (20); and a pair of prism pairs (31) for polarizing the light transmitted through the first positive lens groups (20) and causing the resultant light to be incident on the second positive lens group (40), the prism pairs (31) being disposed between the pair of first positive lens groups (20) and the second positive lens group (40).

Description

立体視内視鏡光学系Stereoscopic endoscope optical system
　本発明は、立体視内視鏡光学系に関するものである。 The present invention relates to a stereoscopic endoscope optical system.
　従来、視差を有する２つの画像を略同一の平面上に結像する光学系を備える立体視内視鏡が知られている（例えば、特許文献１および特許文献２参照。）。
　特許文献１の光学系は、物体側から順に配列された負のパワーを有する１組の第１群レンズと、正のパワーを有する２組の第２群レンズとを備えている。また、特許文献２の光学系は、物体側から順に配列された負のパワーを有する２組の第１群レンズと、正のパワーを有する１組の第２群レンズとを備えている。 Conventionally, a stereoscopic endoscope including an optical system that forms two images having parallax on substantially the same plane is known (see, for example, Patent Document 1 and Patent Document 2).
The optical system of Patent Document 1 includes a pair of first group lenses having negative power and an array of second group lenses having two positive powers arranged in order from the object side. Further, the optical system of Patent Document 2 includes two sets of first group lenses having negative power arranged in order from the object side, and one set of second group lenses having positive power.
　これらの光学系は、第１群レンズの光軸と第２群レンズの光軸とを偏心させて配置することにより、被写体から第１群レンズに左右に間隔をあけて入射された２つの光束が第１群レンズおよび第２群レンズを通過する間にこれら２つの光束の間隔を偏向して、同じく左右に並べて配置された撮像素子の撮像面に結像させることとしている。 These optical systems are arranged so that the optical axis of the first group lens and the optical axis of the second group lens are decentered, so that two light beams incident from the subject to the first group lens with a left-right spacing. While passing through the first group lens and the second group lens, the interval between these two light beams is deflected to form an image on the image pickup surface of the image pickup device that is also arranged side by side.
米国特許第５１９１２０３号明細書US Pat. No. 5,191,203 特開平８－１２２６６５号公報JP-A-8-122665
　しかしながら、２つの光束の間隔をレンズの偏心のみによって調節する場合、光束の大部分がレンズの軸外に入射されて光軸に対して傾斜して通過するため、収差を小さく抑えるには、光軸方向の寸法を十分に確保する必要があり、小型化を図ることができないという不都合がある。特に、内視鏡装置においては、挿入部の先端に配置される光学系を光軸方向に短縮する必要がある。 However, when the distance between the two light beams is adjusted only by the eccentricity of the lens, most of the light beams are incident off the axis of the lens and pass through the optical axis at an angle. There is an inconvenience that it is necessary to ensure a sufficient dimension in the axial direction, and it is impossible to reduce the size. In particular, in an endoscope apparatus, it is necessary to shorten the optical system arranged at the distal end of the insertion portion in the optical axis direction.
　本発明は、光学性能を向上しつつ光軸方向の寸法を短縮することができる立体視内視鏡光学系を提供することを目的としている。 It is an object of the present invention to provide a stereoscopic endoscope optical system that can shorten the dimension in the optical axis direction while improving optical performance.
　上記目的を達成するために、本発明は以下の手段を提供する。
　本発明の態様は、内視鏡の挿入部の先端に配置され、物体側から順に、左右に間隔をあけてそれぞれの光軸が配置された一対の負のレンズ群と、各該負のレンズ群の後段に同軸に配置された一対の第１の正のレンズ群と、該第１の正のレンズ群に対して偏心して配置された第２の正のレンズ群と、一対の前記第１の正のレンズ群と前記第２の正のレンズ群との間に配置され、各前記第１の正のレンズ群を透過した光を偏向して前記第２の正のレンズ群に入射させる一対の光軸偏向部材とを備える立体視内視鏡光学系である。 In order to achieve the above object, the present invention provides the following means.
Aspects of the present invention include a pair of negative lens groups arranged at the distal end of an insertion portion of an endoscope and arranged in order from the object side with respective optical axes spaced from each other on the left and right sides, and the negative lenses. A pair of first positive lens groups disposed coaxially behind the group, a second positive lens group disposed eccentrically with respect to the first positive lens group, and a pair of the first lenses A pair of lens elements disposed between the first positive lens group and the second positive lens group, and deflects the light transmitted through the first positive lens group and makes it incident on the second positive lens group. This is a stereoscopic endoscope optical system including the optical axis deflection member.
　本態様によれば、物体からの２つの光束は、負のレンズ群により発散されて第１の正のレンズ群により収束された後、光軸偏向部材によって偏向されてその２つの光束の間隔が変更されることで、第１の正のレンズ群に対して偏心して配置された第２の正のレンズ群の光軸上にそれぞれ入射される。 According to this aspect, the two light beams from the object are diverged by the negative lens group and converged by the first positive lens group, and then deflected by the optical axis deflecting member, so that the distance between the two light beams is increased. By being changed, the light beam is incident on the optical axis of the second positive lens unit arranged eccentrically with respect to the first positive lens unit.
　この場合において、レンズの偏心のみによって２つの光束の間隔を調節する場合のように光軸方向の寸法を十分に確保しなくても、光軸偏向部材を通過させるだけで、第２の正のレンズ群の位置に合わせて光束の間隔を調節することができる。また、物体に対して負のレンズ群および正のレンズ群の後段に光軸偏向部材を配置することで、光軸偏向部材に略平行な光束の光を入射させて、光軸偏向部材における収差の発生を抑制することができる。したがって、光軸方向の寸法の短縮および光学性能の向上を図ることができる。 In this case, the second positive beam can be simply passed through the optical axis deflecting member without sufficiently securing the dimension in the optical axis direction as in the case where the distance between the two light beams is adjusted only by the eccentricity of the lens. The interval between the light beams can be adjusted according to the position of the lens group. Further, by arranging the optical axis deflecting member downstream of the negative lens group and the positive lens group with respect to the object, light in a substantially parallel light beam is incident on the optical axis deflecting member, and aberrations in the optical axis deflecting member Can be suppressed. Therefore, it is possible to shorten the dimension in the optical axis direction and improve the optical performance.
　上記態様においては、前記光軸偏向部材が、前記第１の正のレンズ群を透過した光を２回偏向して前記第２の正のレンズ群に入射させる透過型のプリズムであることとしてもよい。
　このように構成することで、複数のミラーの反射によって光を偏向させる場合のようなミラーの反射面間の位置調節を不要とし、像の倒れの発生を防止することができる。 In the above aspect, the optical axis deflecting member may be a transmissive prism that deflects light transmitted through the first positive lens group twice and enters the second positive lens group. Good.
With this configuration, it is not necessary to adjust the position between the reflecting surfaces of the mirrors as in the case of deflecting light by the reflection of a plurality of mirrors, and the occurrence of image tilt can be prevented.
　上記態様においては、前記光軸偏向部材が、少なくとも１つの反射面により構成されることとしてもよい。
　このように構成することで、第１の正のレンズ群を透過した光が反射面によって反射されることにより偏向されて、第１の正のレンズ群に対して偏心して配置された第２の正のレンズ群に入射される。したがって、第１の正のレンズ群の光軸と第２の正のレンズ群の光軸とが平行ではない場合において、反射面の角度を調整することで、第１の正のレンズからの光を偏向して第２の正のレンズ群の光軸の中心近くに入射させることができる。 In the above aspect, the optical axis deflecting member may be configured by at least one reflecting surface.
With this configuration, the light transmitted through the first positive lens group is deflected by being reflected by the reflecting surface, and is decentered with respect to the first positive lens group. Incident to the positive lens group. Therefore, when the optical axis of the first positive lens group and the optical axis of the second positive lens group are not parallel, the light from the first positive lens is adjusted by adjusting the angle of the reflecting surface. To be incident near the center of the optical axis of the second positive lens group.
　上記態様においては、前記第２の正のレンズ群が、一対の前記第１の正のレンズ群に対応して一対設けられていることとしてもよい。
　このように構成することで、一対の第１の正のレンズ群を透過した光が一対の第２の正のレンズ群にそれぞれ入射される。 In the above aspect, a pair of the second positive lens group may be provided corresponding to the pair of the first positive lens groups.
With this configuration, light transmitted through the pair of first positive lens groups is incident on the pair of second positive lens groups, respectively.
　上記態様においては、一対の前記第２の正のレンズ群を構成するレンズ対が一体的に成形されていることとしてもよい。
　このように構成することで、第２の正のレンズ群を構成するレンズ対の共有化により、レンズの製作を容易にすることができる。 In the above aspect, the pair of lenses constituting the pair of second positive lens groups may be integrally formed.
With this configuration, the lens can be easily manufactured by sharing the lens pair constituting the second positive lens group.
　上記態様においては、一対の前記第２の正のレンズ群が、一対の前記第１の正のレンズ群の配列方向に対して直交する方向に配列されていることとしてもよい。
　このように構成することで、同一の被写体から発せられた一方向に間隔をあけて並列する視差のある２つの光束を、その並列方向に直交する方向に並んだ２つの光束として撮像面に入射させて立体撮影を行うことができる。したがって、第１の正のレンズ群の並列方向に長くこれに直交する方向に短い断面形状に形成された２つの光束が、それぞれ短辺方向に並んで結像されるので、視差が比較的大きい場合であっても、結像の中心位置を精度よく近接させることができる。 In the above aspect, the pair of second positive lens groups may be arranged in a direction orthogonal to the arrangement direction of the pair of first positive lens groups.
With this configuration, two light beams having a parallax emitted from the same subject and spaced in parallel in one direction are incident on the imaging surface as two light beams aligned in a direction perpendicular to the parallel direction. Stereoscopic imaging can be performed. Accordingly, the two light beams formed in a cross-section that is long in the direction parallel to the first positive lens group and short in the direction perpendicular thereto are imaged side by side in the short-side direction, so that the parallax is relatively large. Even in this case, the center position of the image formation can be brought close with high precision.
　上記態様においては、一対の前記負のレンズ群および一対の前記第１の正のレンズ群を構成する左右のレンズ対が、一体的に成形されていることとしてもよい。
　このように構成することで、視差を有する２つの画像を形成する光線を交差させて、光軸方向の寸法をより短縮することができる。 In the above aspect, the left and right lens pairs constituting the pair of negative lens groups and the pair of first positive lens groups may be integrally formed.
By comprising in this way, the light beam which forms two images which have parallax can be made to cross | intersect, and the dimension of an optical axis direction can be shortened more.
　上記態様においては、一対の前記負のレンズ群および一対の前記第１の正のレンズ群をそれぞれ全周にわたって遮光する筒状の遮光部材を備えることとしてもよい。
　このように構成することで、迷光を低減することができる。 In the above aspect, a cylindrical light shielding member that shields light from the pair of negative lens groups and the pair of first positive lens groups over the entire circumference may be provided.
With this configuration, stray light can be reduced.
　上記態様においては、前記光軸偏向部材の内部に、瞳位置が配置されていることとしてもよい。
　このように構成することで、光軸偏向部材の内部で光を集め、光軸偏向部材の軸方向の寸法を小さくすることができる。 In the above aspect, a pupil position may be disposed inside the optical axis deflection member.
With this configuration, light can be collected inside the optical axis deflection member, and the axial dimension of the optical axis deflection member can be reduced.
　本発明によれば、光学性能を向上しつつ光軸方向の寸法を短縮することができるという効果を奏する。 According to the present invention, it is possible to shorten the dimension in the optical axis direction while improving the optical performance.
本発明の第１実施形態に係る立体視内視鏡光学系を示す概略構成図である。1 is a schematic configuration diagram illustrating a stereoscopic endoscope optical system according to a first embodiment of the present invention. 図１の立体視内視鏡光学系のレンズ構成図である。It is a lens block diagram of the stereoscopic endoscope optical system of FIG. 本発明の第２実施形態に係る立体視内視鏡光学系を負のレンズ群の並列方向に直交する方向から見た概略構成図である。It is the schematic block diagram which looked at the stereoscopic endoscope optical system which concerns on 2nd Embodiment of this invention from the direction orthogonal to the parallel direction of a negative lens group. 図３を負のレンズ群の並列方向に直交する方向から見た概略構成図である。It is the schematic block diagram which looked at FIG. 3 from the direction orthogonal to the parallel direction of a negative lens group. 図３の立体視内視鏡光学系の斜視図である。FIG. 4 is a perspective view of the stereoscopic endoscope optical system of FIG. 3. 図３の立体視内視鏡光学系を物体側から軸方向に見た斜視図である。FIG. 4 is a perspective view of the stereoscopic endoscope optical system of FIG. 3 as viewed in the axial direction from the object side. 図３の立体視内視鏡光学系を負のレンズ群の並列方向に直交する方向から見た斜視図である。It is the perspective view which looked at the stereoscopic endoscope optical system of FIG. 3 from the direction orthogonal to the parallel direction of a negative lens group. 図３の立体視内視鏡光学系を負のレンズ群の並列方向にから見た斜視図である。It is the perspective view which looked at the stereoscopic endoscope optical system of FIG. 3 from the parallel direction of the negative lens group. 図６および図７の矢印Ａ方向から見たミラーを示す図である。It is a figure which shows the mirror seen from the arrow A direction of FIG. 6 and FIG. 図９Ａの矢印Ｂ方向から見たミラーを示す図である。It is a figure which shows the mirror seen from the arrow B direction of FIG. 9A. 図９Ａのミラーを撮像素子側から見た様子を示す図である。It is a figure which shows a mode that the mirror of FIG. 9A was seen from the image pick-up element side. 図３のプリズムミラー対のミラーどうしの接合部には設けられた絞りを示す図である。It is a figure which shows the aperture | diaphragm provided in the junction part of the mirrors of the prism mirror pair of FIG. 図３の立体視内視鏡光学系のレンズ構成図である。It is a lens block diagram of the stereoscopic endoscope optical system of FIG. 本発明の第２実施形態の変形例に係る立体視内視鏡光学系を負のレンズ群の並列方向に直交する方向から見た概略構成図である。It is the schematic block diagram which looked at the stereoscopic endoscope optical system which concerns on the modification of 2nd Embodiment of this invention from the direction orthogonal to the parallel direction of a negative lens group. 図１２を負のレンズ群の並列方向に直交する方向から見た概略構成図である。It is the schematic block diagram which looked at FIG. 12 from the direction orthogonal to the parallel direction of a negative lens group. 図１２の立体視内視鏡光学系の斜視図である。It is a perspective view of the stereoscopic endoscope optical system of FIG. 図１２の立体視内視鏡光学系を物体側から軸方向に見た斜視図である。FIG. 13 is a perspective view of the stereoscopic endoscope optical system of FIG. 12 as viewed in the axial direction from the object side. 図１２の立体視内視鏡光学系を負のレンズ群の並列方向に直交する方向から見た斜視図である。It is the perspective view which looked at the stereoscopic endoscope optical system of FIG. 12 from the direction orthogonal to the parallel direction of a negative lens group. 図１２の立体視内視鏡光学系を負のレンズ群の並列方向に見た斜視図である。It is the perspective view which looked at the stereoscopic endoscope optical system of FIG. 12 in the parallel direction of the negative lens group. 図１５の矢印Ｃ方向から見たミラーを示す図である。It is a figure which shows the mirror seen from the arrow C direction of FIG. 図１８Ａの矢印Ｄ方向から見たミラーを示す図である。It is a figure which shows the mirror seen from the arrow D direction of FIG. 18A. プリズムミラー対のミラーどうしの接合部には設けられた絞りを示す図である。It is a figure which shows the stop provided in the junction part of the mirrors of a prism mirror pair. 図１２の立体視内視鏡光学系のレンズ構成図である。It is a lens block diagram of the stereoscopic endoscope optical system of FIG. 本発明の第３実施形態に係る立体視内視鏡光学系を負のレンズ群の並列方向に見た概略構成図である。It is the schematic block diagram which looked at the stereoscopic endoscope optical system which concerns on 3rd Embodiment of this invention in the parallel direction of the negative lens group.
　〔第１実施形態〕
　本発明の第１実施形態に係る立体視内視鏡光学系について図面を参照して以下に説明する。
　本実施形態に係る立体視内視鏡光学系１００は、内視鏡の挿入部の先端に配置することができるようになっている。この立体視内視鏡光学系１００は、図１に示されるように、物体側から順に配置された、一対の負のレンズ群１０と、負のレンズ群１０を透過した光が入射される一対の第１の正のレンズ群２０と、第１の正のレンズ群２０を透過した光を偏向するプリズム対（光軸偏向部材）３０と、プリズム対３０により偏向された光が入射される第２の正のレンズ群４０とを備えている。 [First Embodiment]
A stereoscopic endoscope optical system according to a first embodiment of the present invention will be described below with reference to the drawings.
The stereoscopic endoscope optical system 100 according to the present embodiment can be disposed at the distal end of the insertion portion of the endoscope. As shown in FIG. 1, the stereoscopic endoscope optical system 100 includes a pair of negative lens groups 10 arranged in order from the object side, and a pair into which light transmitted through the negative lens group 10 is incident. The first positive lens group 20, the prism pair (optical axis deflecting member) 30 that deflects the light transmitted through the first positive lens group 20, and the light deflected by the prism pair 30 is incident thereon. 2 positive lens groups 40.
　一対の負のレンズ群１０は、一体的に成形された左右のレンズ対１１により構成されており、共通の光路を有している。この負のレンズ群１０には、レンズ対１１の各光軸が左右に間隔をあけてそれぞれ配置されている。また、一対の負のレンズ群１０は負の屈折力を有している。これにより、一対の負のレンズ群１０は、物体側に配置されている被写体の広い範囲から発せられた光を集めることができるようになっている。 The pair of negative lens groups 10 includes a pair of left and right lenses 11 that are integrally molded, and has a common optical path. In the negative lens group 10, the optical axes of the lens pair 11 are respectively arranged with a space left and right. The pair of negative lens groups 10 has a negative refractive power. Thereby, the pair of negative lens groups 10 can collect light emitted from a wide range of subjects arranged on the object side.
　第１の正のレンズ群２０は、軸方向に配列された２つのレンズ対２１，２３により構成されている。これらレンズ対２１，２３は、一対の負のレンズ群１０のレンズ対１１と同軸に配置されており、それぞれ一体的に成形されている。また、第１の正のレンズ群２０は光を収束する正の屈折力を有している。 The first positive lens group 20 includes two lens pairs 21 and 23 arranged in the axial direction. These lens pairs 21 and 23 are disposed coaxially with the lens pair 11 of the pair of negative lens groups 10 and are integrally molded. The first positive lens group 20 has a positive refractive power for converging light.
　このように、一対の負のレンズ群１０を構成する左右のレンズ対１１および一対の第１の正のレンズ群２０を構成する左右のレンズ対２１，２３をそれぞれ一体的に成形することで、視差を有する２つの画像を形成する光線を交差させて、光軸方向の寸法をより短縮することができる。 In this way, the left and right lens pairs 11 and 21 and the left and right lens pairs 21 and 23 constituting the pair of first positive lens groups 20 are integrally molded, respectively. It is possible to further reduce the dimension in the optical axis direction by intersecting the light rays forming two images having parallax.
　プリズム対３０は、第１の正のレンズ群２０からの光を２回偏向して透過させて、第２の正のレンズ群４０に入射させるようになっている。このプリズム対３０は、例えば、平行６面体からなる２つの平行四辺形のプリズム３１により構成されている。 The prism pair 30 deflects and transmits the light from the first positive lens group 20 twice and makes it incident on the second positive lens group 40. The prism pair 30 is composed of, for example, two parallelogram prisms 31 made of parallelepipeds.
　各プリズム３１は、負のレンズ群１０を構成するレンズ対１１の並列方向に沿って配列されている。これらのプリズム３１は、相互に平行な入射面３１ａおよび出射面３１ｂを備えている。各プリズム３１の入射面３１ａおよび出射面３１ｂは、一対の第１の正のレンズ群２０から出射された光束の光軸の間隔を広げるように配置されている。 The prisms 31 are arranged along the parallel direction of the lens pair 11 constituting the negative lens group 10. These prisms 31 have an entrance surface 31a and an exit surface 31b that are parallel to each other. The entrance surface 31a and the exit surface 31b of each prism 31 are arranged so as to widen the distance between the optical axes of the light beams emitted from the pair of first positive lens groups 20.
　具体的には、プリズム３１は、第１の正のレンズ群２０によって形成された光束を入射面３１ａから入射する際に光軸の間隔を広げる方向に偏向し、出射面３１ｂでは光束を出射する際に光軸の間隔を平行にする方向に偏向するようになっている。プリズム３１の入射面３１ａと出射面３１ｂの距離を調整することで、第１の正のレンズ群２０の光軸と第２の正のレンズ群４０の光軸とが一致するようになっている。 Specifically, the prism 31 deflects the light beam formed by the first positive lens group 20 in the direction of widening the interval between the optical axes when entering from the incident surface 31a, and emits the light beam on the output surface 31b. At this time, the optical axis is deflected in a direction to make it parallel. By adjusting the distance between the entrance surface 31a and the exit surface 31b of the prism 31, the optical axis of the first positive lens group 20 and the optical axis of the second positive lens group 40 coincide with each other. .
　これにより、一対の第１の正のレンズ群１０を通過した２つの光束は、一対のプリズム対３０を通過することによって、その並列方向を変更されることなくその光軸の間隔のみを拡大させられて第２の正のレンズ群２０に入射されるようになっている。 As a result, the two light beams that have passed through the pair of first positive lens groups 10 pass through the pair of prism pairs 30 to enlarge only the interval between the optical axes without changing the parallel direction thereof. And is incident on the second positive lens group 20.
　第２の正のレンズ群４０は、一対の第１の正のレンズ群２０に対応して一対設けられており、一体的に成形されたレンズ対４１により構成されている。また、第２の正のレンズ群４０は、第１の正のレンズ群２０に対して偏心して配置されており、プリズム３１により偏向された光を収束する正の屈折力を有している。この第２の正のレンズ群４０から出射された光束は、その後段に配置されているＣＣＤのような撮像素子５０の撮像面５１ａに入射されるようになっている。 The second positive lens group 40 is provided as a pair corresponding to the pair of first positive lens groups 20, and is configured by an integrally molded lens pair 41. The second positive lens group 40 is arranged eccentrically with respect to the first positive lens group 20 and has a positive refractive power for converging the light deflected by the prism 31. The light beam emitted from the second positive lens group 40 is incident on the image pickup surface 51a of the image pickup device 50 such as a CCD arranged at the subsequent stage.
　本実施形態に係る立体視内視鏡光学系１００のレンズ構成を図２に示し、レンズデータを下記に示す。この立体視内視鏡光学系１００は、例えば、物体距離が２０ｍｍ、焦点距離が０．６１８７ｍｍ、Ｆ値が４．２、撮像エリア（片側）が０．６ｍｍ×０．８ｍｍ、負のレンズ群１０のレンズ間隔が０．７ｍｍ、左右の像の結像間隔が１．０ｍｍとなっている。図２において、符号ｒｎ（ｎ＝０，１，２・・）は面番号ｎの曲面を示し、符号Ｌｎは面番号ｎの面間隔を示している。図９，１６において同様である。 FIG. 2 shows a lens configuration of the stereoscopic endoscope optical system 100 according to the present embodiment, and lens data is shown below. The stereoscopic endoscope optical system 100 has, for example, an object distance of 20 mm, a focal length of 0.6187 mm, an F value of 4.2, an imaging area (one side) of 0.6 mm × 0.8 mm, a negative lens group The lens interval of 10 is 0.7 mm, and the imaging interval of the left and right images is 1.0 mm. In FIG. 2, a symbol rn (n = 0, 1, 2,...) Indicates a curved surface having a surface number n, and a symbol Ln indicates a surface interval of the surface number n. The same applies to FIGS.
レンズデータ
面番号　　　半径　　　　　　距離　　　　　屈折率　　　　　　分散
　0　　　　　∞　　　　　　0.24　　　　　1.88815　　　　　　40.7645
　1　　　　0.391285　　　　0.18　
　2　　　　4.44471　　　　 0.18　　　　　1.88815　　　　　　40.7645
　3　　　　0.84　　　　　　0.36　　　　　1.58565　　　　　　46.4224
　4　　　－1.08018　　　　 0.12
　5　　　－6.86009　　　　 0.42　　　　　1.51825　　　　　　64.1411
　6　　　－0.64267　　　　 0.18
　7　　　　　∞　　　　　　0.72　　　　　1.51564　　　　　　75.009
　8　　　　　∞　　　　　　0.268192　
　9　　　　0.97587　　　　 0.78　　　　　1.57124　　　　　　56.363
　10　　 －0.79221　　　　 0.29474　　　 1.93429　　　　　　18.8966
　11　　 －4.1074　　　　　0.601262
　プリズム３１を構成する面ｒ７、ｒ８の傾き角は３２．５°を有している。 Lens data surface number Radius Distance Refractive index Dispersion 0 ∞ 0.24 1.88815 40.7645
1 0.391285 0.18
2 4.44471 0.18 1.88815 40.7645
3 0.84 0.36 1.58565 46.4224
4 -1.08018 0.12
5 -6.86009 0.42 1.51825 64.1411
6 -0.64267 0.18
7 ∞ 0.72 1.51564 75.009
8 ∞ 0.268192
9 0.97587 0.78 1.57124 56.363
10 -0.79221 0.29474 1.93429 18.8966
11 -4.1074 0.601262
The inclination angles of the surfaces r7 and r8 constituting the prism 31 are 32.5 °.
　このように構成された本実施形態に係る立体視内視鏡光学系１００の作用について説明する。
　本実施形態に係る立体視内視鏡光学系１００によれば、被写体から発せられた光は、間隔をあけた光軸を有する一対の負のレンズ群１０に入射され、負のレンズ群１０により発散されて視差を有する略平行な光束となって出射される。 The operation of the stereoscopic endoscope optical system 100 according to this embodiment configured as described above will be described.
According to the stereoscopic endoscope optical system 100 according to the present embodiment, light emitted from a subject is incident on a pair of negative lens groups 10 having an optical axis spaced apart from each other. The light is diverged and emitted as a substantially parallel light beam having parallax.
　負のレンズ群１０から出射された光束は、その後段に配置されている第１の正のレンズ群２０にそれぞれ入射して収束される。第１の正のレンズ群２０を透過した光束は、プリズム対３０を構成するプリズム３１の入射面３１に入射される。 The luminous flux emitted from the negative lens group 10 is incident on and converged on the first positive lens group 20 disposed in the subsequent stage. The light beam that has passed through the first positive lens group 20 is incident on the incident surface 31 of the prism 31 that constitutes the prism pair 30.
　プリズム対３０内に入射した光束は、入射面３１ａにおいて光軸の間隔を広げる方向に偏向された後、出射面３１ｂにおいて光軸の間隔を平行にする方向に偏向されて出射される。これにより、一対のプリズム対３０に入射された２つの光束は、その並列方向を変更されることなくその光軸の間隔のみを拡大させられてプリズム対３０を通過し、第１の正のレンズ群２０に対して偏心して配置された第２の正のレンズ群４０の光軸上にそれぞれ入射される。 The light beam that has entered the prism pair 30 is deflected in a direction in which the interval between the optical axes is widened on the incident surface 31a, and then is deflected in the direction in which the interval between the optical axes is paralleled on the exit surface 31b. As a result, the two light beams incident on the pair of prisms 30 pass through the prism pair 30 with only the interval between the optical axes enlarged without changing the parallel direction of the first positive lens. The light beams are incident on the optical axis of the second positive lens group 40 arranged eccentrically with respect to the group 20.
　第２の正のレンズ群４０に入射された光束は、それぞれ収束されて出射されて撮像素子５０の撮像面５１ａに入射される。これにより、視差を有する２つの画像が撮像素子５０の同一の撮像面５１ａ上に結像される。 The light beams incident on the second positive lens group 40 are converged and emitted, and enter the imaging surface 51a of the imaging device 50. Thereby, two images having parallax are formed on the same imaging surface 51 a of the imaging element 50.
　以上説明したように本実施形態に係る立体視内視鏡光学系１００によれば、プリズム対３０により光を偏向することで、偏向レンズの偏心のみによって２つの光束の間隔を調節する場合のように光軸方向の寸法を十分に確保しなくても、第２の正のレンズ群４０の位置に合わせて光束の間隔を調節することができる。また、物体に対して負のレンズ群１０および第１の正のレンズ群２０の後段にプリズム対３０を配置することで、プリズム対３０に略平行な光束の光を入射させて、プリズム対３０における収差の発生を抑制することができる。これにより、光学性能の向上および光軸方向の寸法の短縮化を図ることができる。 As described above, according to the stereoscopic endoscope optical system 100 according to the present embodiment, the light is deflected by the prism pair 30 so that the interval between the two light beams is adjusted only by the eccentricity of the deflection lens. Even if the dimension in the optical axis direction is not sufficiently secured, the interval between the light beams can be adjusted according to the position of the second positive lens group 40. In addition, by arranging the prism pair 30 at the subsequent stage of the negative lens group 10 and the first positive lens group 20 with respect to the object, light of a substantially parallel light beam is incident on the prism pair 30, and the prism pair 30. Occurrence of aberrations can be suppressed. Thereby, the optical performance can be improved and the dimension in the optical axis direction can be shortened.
〔第２実施形態〕
　次に、本発明の第２実施形態に係る立体視内視鏡光学系２００について、以下に説明する。
　本実施形態に係る立体視内視鏡光学系２００は、図３～図１１に示すように、光軸偏向部材としてプリズム対３０に代えて、光を反射して偏向するために、それぞれ１つの反射面を有する三角柱のプリズムを張り合わせ、相互に平行な２つの反射面１３１ａ，１３１ｂを備えるプリズムミラー対１３０を採用する点と、一対の第２の正のレンズ群４０に代えて、一対の第１の正のレンズ群１２０の配列方向に対して直交する方向に配列されている一対の第２の正のレンズ群１４０を備える点で、第１実施形態と異なる。
　以下、第１実施形態に係る立体視内視鏡光学系１００と構成を共通する箇所には、同一符号を付して説明を省略する。 [Second Embodiment]
Next, the stereoscopic endoscope optical system 200 according to the second embodiment of the present invention will be described below.
As shown in FIG. 3 to FIG. 11, the stereoscopic endoscope optical system 200 according to the present embodiment has one each for reflecting and deflecting light instead of the prism pair 30 as an optical axis deflecting member. Instead of the pair of second positive lens groups 40, a pair of second positive lens groups 40 is employed, in which a prismatic prism 130 having two reflective surfaces 131a and 131b parallel to each other is adopted. The second embodiment differs from the first embodiment in that it includes a pair of second positive lens groups 140 arranged in a direction orthogonal to the arrangement direction of the first positive lens group 120.
In the following, portions having the same configuration as those of the stereoscopic endoscope optical system 100 according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.
　一対の負のレンズ群１１０は、軸方向に配列された２つのレンズ対１３，１５により構成され、これらレンズ対１３，１５が一方向に間隔をあけて並列して配置されている。
　第１の正のレンズ群１２０は、軸方向に配列された２つのレンズ対２５，２７により構成されている。これらレンズ対２５，２７は、それぞれ一方向に間隔をあけて設けられ、一対の負のレンズ群１１０のレンズ対１３，１５とそれぞれ同軸に配置されている。 The pair of negative lens groups 110 includes two lens pairs 13 and 15 arranged in the axial direction, and these lens pairs 13 and 15 are arranged in parallel at an interval in one direction.
The first positive lens group 120 includes two lens pairs 25 and 27 arranged in the axial direction. These lens pairs 25 and 27 are provided at intervals in one direction, and are arranged coaxially with the lens pairs 13 and 15 of the pair of negative lens groups 110, respectively.
　第２の正のレンズ群１４０は、第１の正のレンズ群１２０を構成するレンズ対２５，２７の並列方向に直交する方向に並列して配置された正の屈折力を有するレンズ対４３，３５により構成されている。第２の正のレンズ群１４０から出射された光束は、その後段に配置されている撮像素子５０の撮像面５１ａにそのまま入射されるようになっている。 The second positive lens group 140 includes a lens pair 43 having a positive refractive power and arranged in parallel in a direction orthogonal to the parallel direction of the lens pairs 25 and 27 constituting the first positive lens group 120. 35. The light beam emitted from the second positive lens group 140 is directly incident on the image pickup surface 51a of the image pickup element 50 arranged at the subsequent stage.
　すなわち、一対の第２の正のレンズ群１４０によって、一対の第１の正のレンズ群１２０の各レンズ対２５，２７の並列方向に長く、これに直交する方向に短い断面形状に形成された光束が、第１の正のレンズ群１２０の各レンズ対２５，２７の並列方向に直交する方向に並んで撮像面５１ａに入射されるようになっている。 That is, the pair of second positive lens groups 140 are formed in a cross-sectional shape that is long in the parallel direction of the lens pairs 25 and 27 of the pair of first positive lens groups 120 and short in the direction perpendicular thereto. The luminous flux is incident on the imaging surface 51 a side by side in a direction orthogonal to the parallel direction of the lens pairs 25 and 27 of the first positive lens group 120.
　プリズムミラー対１３０は、第１の正のレンズ群１２０からの光を２回反射して第２の正のレンズ群１４０に入射させるようになっている。このプリズムミラー対１３０は、相互に平行に配置された２つの反射面１３１ａ，１３１ｂを有する２つのミラー１３１により構成されている。 The prism mirror pair 130 reflects the light from the first positive lens group 120 twice and makes it incident on the second positive lens group 140. The prism mirror pair 130 includes two mirrors 131 having two reflecting surfaces 131a and 131b arranged in parallel to each other.
　また、プリズムミラー対１３０は、例えば、図６に示すように、第１の正のレンズ群１２０の配列方向に対して２２．２°傾けられて配置されている。図６および図７に示す矢印Ａ方向から見たミラー１３１を図９Ａに示す。また、図９Ａのミラー１３１を矢印Ｂ方向（ミラー１３１どうしが重なる方向）に見た様子を図９Ｂに示し、図９Ａのミラー１３１を撮像素子５０側から見た様子を図９Ｃに示す。 Further, for example, as shown in FIG. 6, the prism mirror pair 130 is disposed at an angle of 22.2 ° with respect to the arrangement direction of the first positive lens group 120. The mirror 131 viewed from the direction of arrow A shown in FIGS. 6 and 7 is shown in FIG. 9A. 9A shows a state where the mirror 131 of FIG. 9A is viewed in the arrow B direction (direction in which the mirrors 131 overlap), and FIG. 9C shows a state where the mirror 131 of FIG. 9A is viewed from the image sensor 50 side.
　各ミラー１３１の反射面１３１ａは、一対の第１の正のレンズ群１２０に対してそれぞれ傾斜して対向するように設けられ、各第１の正のレンズ群１１０の光軸にそれぞれ一致する位置にその中心位置が配置されている。また、各ミラー１３１の反射面１３１ｂは、一対の第２の正のレンズ群１４０に対してそれぞれ傾斜して対向するように設けられ、各第２の正のレンズ群１４０の光軸にそれぞれ一致する位置にその中心位置が配置されている。 The reflecting surfaces 131a of the mirrors 131 are provided so as to be inclined and opposed to the pair of first positive lens groups 120, respectively, and positions corresponding to the optical axes of the first positive lens groups 110, respectively. The center position is arranged. In addition, the reflecting surface 131b of each mirror 131 is provided so as to be inclined and opposed to the pair of second positive lens groups 140, and coincides with the optical axis of each second positive lens group 140. The center position is arranged at the position to be.
　すなわち、一対のプリズムミラー対１３０は、各第１の正のレンズ群１２０を構成する各レンズ対２５，２７の並列方向に直交する方向にその中心位置が並列して配置されており、一対の第１の正のレンズ群１２０の光軸の並列方向を９０°回転させるように光束を変換するようになっている。 That is, the pair of prism mirrors 130 is arranged in parallel at the center position in the direction orthogonal to the parallel direction of the lens pairs 25 and 27 constituting each first positive lens group 120. The light beam is converted so that the parallel direction of the optical axes of the first positive lens group 120 is rotated by 90 °.
　また、プリズムミラー対１３０は、ミラー１３１どうしの接合部に、図１０に示すような絞り３３を有し、内部に瞳位置が配置されている。これにより、プリズムミラー対１３０の内部で光を集め、プリズムミラー対１３０の軸方向の寸法を小さくすることができる。絞り３３は、例えば、直径が０．３６ｍｍを有している。図９Ａ、図９Ｃおよび図１０において、符合１３１ｃはミラー１３１どうしの接合部を示している。 Also, the prism mirror pair 130 has a diaphragm 33 as shown in FIG. 10 at the joint between the mirrors 131, and the pupil position is arranged inside. Thereby, the light can be collected inside the prism mirror pair 130 and the axial dimension of the prism mirror pair 130 can be reduced. The diaphragm 33 has, for example, a diameter of 0.36 mm. 9A, 9 </ b> C, and 10, reference numeral 131 c indicates a joint portion between the mirrors 131.
　本実施形態に係る立体視内視鏡光学系２００のレンズ構成を図１１に示し、レンズデータを下記に示す。この立体視内視鏡光学系２００は、例えば、物体距離が３６ｍｍ、焦点距離が１．１ｍｍ、Ｆ値が６．２、撮像エリア（片側）が０．９ｍｍ×０．６８ｍｍ、負のレンズ群１０のレンズ間隔が２．０ｍｍ、左右の像の結像間隔が０．８３１２ｍｍを有している。 FIG. 11 shows a lens configuration of the stereoscopic endoscope optical system 200 according to the present embodiment, and lens data is shown below. The stereoscopic endoscope optical system 200 has, for example, an object distance of 36 mm, a focal length of 1.1 mm, an F value of 6.2, an imaging area (one side) of 0.9 mm × 0.68 mm, a negative lens group The lens interval of 10 is 2.0 mm, and the imaging interval of the left and right images is 0.8312 mm.
レンズデータ
面番号　　　半径　　　　　　距離　　　　　屈折率　　　　　　分散
　1　　　　　∞　　　　　　0.25　　　　　1.7682　　　　　　71.799
　2　　　　　∞　　　　　　0.2
　3　　　－3.88208　　　　 0.2　　　　　 1.8061　　　　　　40.9253
　4　　　　1.0592　　　　　0.1
　5　　　　1.85329　　　　 0.4338　　　　1.84666　　　　　 23.7775
　6　　　　6.81469　　　　 0.099388
　7　　　－3.10035　　　　 0.414536　　　1.883　　　　　　 40.7645
　8　　　－2.57913　　　　 0.0455
　9　　　　∞　　　　　　　2.1　　　　　 1.79952　　　　　 42.2243
　10　　　 ∞　　　　　　　0.115
　11　　　 20.9847　　　　 0.39　　　　　1.883　　　　　　 40.7645
　12　　 －2.6545　　　　　0.025
　13　　　 3.09887　　　　 0.517985　　　1.72916　　　　　 54.6792
　14　　 －1.94096　　　　 0.317985　　　1.92286　　　　　 18.8966
　15　　 －7.8794　　　　　2.08415 Lens data surface number Radius Distance Refractive index Dispersion 1 ∞ 0.25 1.7682 71.799
2 ∞ 0.2
3 -3.88208 0.2 1.8061 40.9253
4 1.0592 0.1
5 1.85329 0.4338 1.84666 23.7775
6 6.81469 0.099388
7 -3.10035 0.414536 1.883 40.7645
8 -2.57913 0.0455
9 ∞ 2.1 1.79952 42.2243
10 ∞ 0.115
11 20.9847 0.39 1.883 40.7645
12 -2.6545 0.025
13 3.09887 0.517985 1.72916 54.6792
14 -1.94096 0.317985 1.92286 18.8966
15 -7.8794 2.08415
　このように構成された本実施形態に係る立体視内視鏡光学系２００の作用について以下に説明する。
　本実施形態に係る立体視内視鏡光学系２００によれば、プリズムミラー対１３０が相互に精度よく平行に製造された２つの反射面１３１ａ，１３１ｂを備えるので、被写体から発せられて一対の負のレンズ群１１０および一対の第１の正のレンズ群１２０を透過した光束は、ミラー１３１において２つの反射面１３１ａ，１３１ｂによって２回反射されて一対の第２の正のレンズ群１４０入射される。 The operation of the stereoscopic endoscope optical system 200 according to this embodiment configured as described above will be described below.
According to the stereoscopic endoscope optical system 200 according to the present embodiment, the prism mirror pair 130 includes the two reflecting surfaces 131a and 131b manufactured in parallel with high accuracy, so that the pair of negative electrodes is emitted from the subject. The light beams transmitted through the lens group 110 and the pair of first positive lens groups 120 are reflected twice by the two reflecting surfaces 131a and 131b in the mirror 131 and are incident on the pair of second positive lens groups 140. .
　各プリズムミラー対１３０は、図６に示すように、第１の正のレンズ群１２０の配列方向に対して２２．２°傾けられて配置され、その反射面１３１ｂは反射面１３１ａの並列方向に対して直交する方向に並列しているので、各反射面１３１ｂから出射される２つの光束は、２つの反射面１３１ａに入射される際の並列方向を９０°回転させられる。そして、ミラー１３１の反射面１３１ｂにより反射された２つの光束は、一対の第２の正のレンズ群１４０に入射され、正の屈折力によって収束されて撮像素子５０に入射される。これにより、視差を有する２つの画像が撮像素子５０の同一の撮像面５１ａ上に結像される。 As shown in FIG. 6, each pair of prism mirrors 130 is disposed at an angle of 22.2 ° with respect to the arrangement direction of the first positive lens group 120, and the reflection surface 131b thereof is parallel to the reflection surface 131a. Since the two light beams emitted from the respective reflecting surfaces 131b are rotated by 90 ° in the parallel direction when entering the two reflecting surfaces 131a. Then, the two light beams reflected by the reflecting surface 131 b of the mirror 131 are incident on the pair of second positive lens groups 140, converged by the positive refractive power, and incident on the image sensor 50. Thereby, two images having parallax are formed on the same imaging surface 51 a of the imaging element 50.
　以上説明したように本実施形態に係る立体視内視鏡光学系２００によれば、同一の被写体から発せられた一方向に間隔をあけて並列する視差のある２つの光束を、その並列方向に直交する方向に並んだ２つの光束として撮像面に入射させて立体撮影を行うことができる。したがって、第１の正のレンズ群１２０の並列方向に長くこれに直交する方向に短い断面形状に形成された２つの光束がそれぞれ短辺方向に２段に並んで結像されるので、視差が比較的大きい場合であっても、結像の中心位置を精度よく近接させることができる。また、２つの光束をそれぞれ短辺方向に２段に並んで結像させることで、撮像素子５０を有効利用することができる。 As described above, according to the stereoscopic endoscope optical system 200 according to this embodiment, two light beams having a parallax emitted from the same subject and spaced in parallel in one direction are arranged in the parallel direction. Stereo imaging can be performed by making two light beams arranged in orthogonal directions incident on the imaging surface. Accordingly, since two light beams formed in a cross-sectional shape that is long in the direction parallel to the first positive lens group 120 and short in the direction perpendicular thereto are imaged in two steps in the short side direction, the parallax is reduced. Even if it is relatively large, the center position of image formation can be brought close to with high precision. Further, the image pickup device 50 can be effectively used by forming two light beams in two rows in the short side direction.
　本実施形態は以下のように変形することができる。
　すなわち、本実施形態においては、立体視内視鏡光学系２００が、一方向に間隔あけて並列して配置されたレンズ対４３，４５により構成された第２の正のレンズ群１４０を備えることとしたが、これに代えて、例えば、図１２～図２０に示すように、それぞれ一体的に成形されたレンズ対４７，４９により構成された第２の正のレンズ群１４１を備えることとしてもよい。
　このようにすることで、第２の正のレンズ群１４１を構成するレンズ対４７，４９の共有化により、レンズの製作を容易にすることができる。 This embodiment can be modified as follows.
That is, in the present embodiment, the stereoscopic endoscope optical system 200 includes the second positive lens group 140 configured by the lens pairs 43 and 45 that are arranged in parallel at an interval in one direction. However, instead of this, for example, as shown in FIGS. 12 to 20, a second positive lens group 141 composed of a pair of lenses 47 and 49 integrally molded may be provided. Good.
In this way, the lens can be easily manufactured by sharing the lens pairs 47 and 49 constituting the second positive lens group 141.
　本変形例においては、例えば、図１５に示すように、プリズムミラー対１３０は、第１の正のレンズ群１２０の配列方向に対して３０°傾けられて配置されている。レンズ対１５は、例えば、光軸間の距離が２．０ｍｍ離れている。図１５に示す矢印Ｃ方向から見たミラー１３１を図１８Ａに示す。また、図１８Ａの矢印Ｄ方向に見たミラー１３１を図１８Ｂに示す。図１８Ｂに示されるように、ミラー１３１の反射面１３１ｂは、例えば、反射面１３１ａに対して１．８４５°傾けられて配置されている。また、例えば、図１９に示すように、絞り３３は直径０．８４ｍｍを有している。 In this modification, for example, as shown in FIG. 15, the prism mirror pair 130 is disposed at an angle of 30 ° with respect to the arrangement direction of the first positive lens group 120. For example, the distance between the optical axes of the lens pair 15 is 2.0 mm. The mirror 131 viewed from the direction of arrow C shown in FIG. 15 is shown in FIG. 18A. 18B shows the mirror 131 viewed in the direction of arrow D in FIG. 18A. As shown in FIG. 18B, the reflection surface 131b of the mirror 131 is disposed at an angle of 1.845 ° with respect to the reflection surface 131a, for example. Further, for example, as shown in FIG. 19, the diaphragm 33 has a diameter of 0.84 mm.
　本変形例に係る立体視内視鏡光学系２００のレンズ構成を図２０に示し、レンズデータを下記に示す。この立体視内視鏡光学系２００は、例えば、物体距離が１００ｍｍ、焦点距離が１．５２２５ｍｍ、Ｆ値が４．７８、撮像エリア（片側）が０．６ｍｍ×０．８ｍｍ、負のレンズ群１１０のレンズ間隔が２．０ｍｍ、左右の像の結像間隔が０．６ｍｍを有している。 FIG. 20 shows a lens configuration of the stereoscopic endoscope optical system 200 according to this modification, and lens data is shown below. This stereoscopic endoscope optical system 200 has, for example, an object distance of 100 mm, a focal length of 1.5225 mm, an F value of 4.78, an imaging area (one side) of 0.6 mm × 0.8 mm, a negative lens group The lens interval of 110 is 2.0 mm, and the imaging interval of the left and right images is 0.6 mm.
レンズデータ
面番号　　　半径　　　　　　距離　　　　　屈折率　　　　　　分散
　1　　　　　∞　　　　　　0.192308　　　1.883　　　　　　　40.7645
　2　　　　0.730093　　　　0.288462　　　1　　　　　　　　　0
　3　　　　4.17455　　　　 0.834291　　　1.80809　　　　　　22.7604
　4　　　－0.62432　　　　 0.179487　　　1.883　　　　　　　40.7645
　5　　　－3.08454　　　　 0.192308　　　1　　　　　　　　　0
　6　　　－2.55081　　　　 0.174905　　　1.92286　　　　　　18.8966
　7　　　　2.87829　　　　 0.514948　　　1.61405　　　　　　54.9893
　8　　　－1.02528　　　　 0.320513　　　1　　　　　　　　　0
　9　　　　無限　　　　　　2.26　　　　　1.804　　　　　　　46.5697
　10　　　 無限　　　　　　1.1　　　　　 1　　　　　　　　　0
　11　　　 4.78258　　　　 1.41026　　　 1.497　　　　　　　81.5447
　12　　 －3.92316　　　　 0.385276　　　1.72342　　　　　　37.955
　13　　 －10.7025　　　　 0.032051　　　1　　　　　　　　　0
　14　　　 2.71385　　　　 1.53846　　　 1.43875　　　　　　94.9446
　15　　 －5.57641　　　　 0.383851　　　1.72　　　　　　　 50.2298
　16　　 －16.9955　　　　 2.26688　　　 1　　　　　　　　　0 Lens data surface number Radius Distance Refractive index Dispersion 1 ∞ 0.192308 1.883 40.7645
2 0.730093 0.288462 1 0
3 4.17455 0.834291 1.80809 22.7604
4 -0.62432 0.179487 1.883 40.7645
5 -3.08454 0.192308 1 0
6 -2.55081 0.174905 1.92286 18.8966
7 2.87829 0.514948 1.61405 54.9893
8 -1.02528 0.320513 1 0
9 Infinite 2.26 1.804 46.5697
10 Infinite 1.1 1 0
11 4.78258 1.41026 1.497 81.5447
12 -3.92316 0.385276 1.72342 37.955
13 -10.7025 0.032051 1 0
14 2.71385 1.53846 1.43875 94.9446
15 -5.57641 0.383851 1.72 50.2298
16 -16.9955 2.26688 1 0
〔第３実施形態〕
　次に、本発明の第３実施形態に係る立体視内視鏡光学系３００について、以下に説明する。
　本実施形態に係る立体視内視鏡光学系３００は、図２１に示すように、光軸偏向部材として、光を反射して偏向する少なくとも１つの反射面２３１ａを有するミラー対２３０を採用する点で、第２実施形態と異なる。
　以下、第１実施形態に係る立体視内視鏡光学系１００、第２実施形態に係る立体視内視鏡光学系２００と構成を共通する箇所には、同一符号を付して説明を省略する。 [Third Embodiment]
Next, the stereoscopic endoscope optical system 300 according to the third embodiment of the present invention will be described below.
As shown in FIG. 21, the stereoscopic endoscope optical system 300 according to the present embodiment employs a mirror pair 230 having at least one reflecting surface 231a that reflects and deflects light as an optical axis deflecting member. This is different from the second embodiment.
Hereinafter, the same reference numerals are given to portions having the same configurations as those of the stereoscopic endoscope optical system 100 according to the first embodiment and the stereoscopic endoscope optical system 200 according to the second embodiment, and description thereof is omitted. .
　本実施形態に係る一対の第２の正のレンズ群１４１は、その光軸が一対の第１の正のレンズ群１２０の各光軸に対して交差するように配置されている。具体的には、一対の第２の正のレンズ群２４１の光軸は、一対の第１の正のレンズ群１２０の光軸に対して略直交するように配置されている。 The pair of second positive lens groups 141 according to the present embodiment are arranged so that the optical axes thereof intersect the optical axes of the pair of first positive lens groups 120. Specifically, the optical axes of the pair of second positive lens groups 241 are arranged so as to be substantially orthogonal to the optical axes of the pair of first positive lens groups 120.
　ミラー対２３０は、それぞれ反射面２３１ａを有するミラー２３１により構成されている。各ミラー２３１は、例えば、一対の第１の正のレンズ群１２０の光軸上に相互に並列して配置されている。また、各ミラー２３１は、それぞれ反射面２３１ａを相互に向き合う方向に傾けつつ、一対の第２の正のレンズ群２４１の配列方向に角度をずらして配置されている。 The mirror pair 230 is composed of mirrors 231 each having a reflecting surface 231a. For example, the mirrors 231 are arranged in parallel with each other on the optical axis of the pair of first positive lens groups 120. In addition, each mirror 231 is arranged with an angle shifted in the arrangement direction of the pair of second positive lens groups 241 while the reflecting surfaces 231a are inclined in the direction facing each other.
　これにより、ミラー対２３０は、一対の第１の正のレンズ群１２０を透過した光を反射面２３１ａにより略直交する方向に反射して偏向し、第２の正のレンズ群２４１の光軸の中心近くに入射さることができるようになっている。そして、第２の正のレンズ群２４１を介して、２つの光束を第１の正のレンズ群１２０の光軸の並列方向に対して９０°回転させるように変換して撮像素子５０の撮像面５１ａに入射させることができるようになっている。 Thereby, the mirror pair 230 reflects and deflects the light transmitted through the pair of first positive lens groups 120 in a direction substantially orthogonal to the reflecting surface 231a, and the optical axis of the second positive lens group 241 is reflected. It can be incident near the center. Then, through the second positive lens group 241, the two light beams are converted so as to be rotated by 90 ° with respect to the parallel direction of the optical axes of the first positive lens group 120, and the imaging surface of the imaging device 50 is converted. It can be made incident on 51a.
　このように構成された本実施形態に係る立体視内視鏡光学系３００によれば、第１の正のレンズ群１２０の光軸と第２の正のレンズ群２４１の光軸とが平行ではない場合において、反射面２３１ａの角度を調整することで、同一の被写体から発せられた一方向に間隔をあけて並列する視差のある２つの光束を偏向して第２の正のレンズ群２４１の光軸の中心近くに入射させ、第１の正の撮像素子１２０の光軸の並列方向に直交する方向に光軸が並んだ２つの光束として撮像面５１ａに入射させて立体撮影を行うことができる。 According to the stereoscopic endoscope optical system 300 according to the present embodiment configured as described above, the optical axis of the first positive lens group 120 and the optical axis of the second positive lens group 241 are not parallel. In the case where there is not, the angle of the reflecting surface 231a is adjusted to deflect two light beams having a parallax that are emitted from the same subject and spaced in parallel in one direction so that the second positive lens group 241 Stereo imaging is performed by making the light incident near the center of the optical axis and entering the imaging surface 51a as two light beams in which the optical axes are arranged in a direction orthogonal to the parallel direction of the optical axis of the first positive imaging element 120. it can.
　以上、本発明の実施形態について図面を参照して詳述してきたが、具体的な構成はこの実施形態に限られるものではなく、本発明の要旨を逸脱しない範囲の設計変更等も含まれる。例えば、本発明を上記の各実施形態に適用したものに限定されることなく、これらの実施形態を適宜組み合わせた実施形態に適用してもよく、特に限定されるものではない。 As described above, the embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like within a scope not departing from the gist of the present invention. For example, the present invention is not limited to those applied to each of the above embodiments, and may be applied to embodiments in which these embodiments are appropriately combined, and is not particularly limited.
　また、上記各実施形態においては、立体視内視鏡光学系１００，２００，３００が、一対の負のレンズ群１０，１１０および一対の第１の正のレンズ群２０，１２０をそれぞれ全周にわたって遮光する筒状の遮光部材を備えることとしてもよい。このようにすることで、迷光を低減することができる。 In each of the above embodiments, the stereoscopic endoscope optical system 100, 200, 300 includes the pair of negative lens groups 10, 110 and the pair of first positive lens groups 20, 120 over the entire circumference. It is good also as providing the cylindrical light-shielding member which light-shields. By doing so, stray light can be reduced.
　１０，１１０　負のレンズ群
　２０，１２０　第１の正のレンズ群
　３０　プリズム対（光軸偏向部材）
　３１　プリズム
　４０，１４０，１４１　第２の正のレンズ群
　１００，２００，３００　立体視内視鏡光学系
　１３０　ミラー対（光軸偏向部材）
　１３１　ミラー
　２３１ａ　反射面 10, 110 Negative lens group 20, 120 First positive lens group 30 Prism pair (optical axis deflecting member)
31 Prism 40, 140, 141 Second positive lens group 100, 200, 300 Stereoscopic endoscope optical system 130 Mirror pair (optical axis deflecting member)
131 mirror 231a reflecting surface

Claims (9)

  1. 　内視鏡の挿入部の先端に配置され、物体側から順に、
    　左右に間隔をあけてそれぞれの光軸が配置された一対の負のレンズ群と、
    　各該負のレンズ群の後段に同軸に配置された一対の第１の正のレンズ群と、
    　該第１の正のレンズ群に対して偏心して配置された第２の正のレンズ群と、
    　一対の前記第１の正のレンズ群と前記第２の正のレンズ群との間に配置され、各前記第１の正のレンズ群を透過した光を偏向して前記第２の正のレンズ群に入射させる一対の光軸偏向部材とを備える立体視内視鏡光学系。     Placed at the tip of the insertion part of the endoscope, in order from the object side,
    A pair of negative lens groups in which the respective optical axes are arranged at intervals on the left and right;
    A pair of first positive lens groups coaxially disposed downstream of each negative lens group;
    A second positive lens group arranged eccentric with respect to the first positive lens group;
    The second positive lens is disposed between a pair of the first positive lens group and the second positive lens group, and deflects light transmitted through each of the first positive lens groups. A stereoscopic endoscope optical system comprising a pair of optical axis deflecting members incident on the group.
  2. 　前記光軸偏向部材が、前記第１の正のレンズ群を透過した光を偏向して前記第２の正のレンズ群に入射させる透過型のプリズムである請求項１に記載の立体視内視鏡光学系。 2. The stereoscopic vision according to claim 1, wherein the optical axis deflecting member is a transmissive prism that deflects light transmitted through the first positive lens group and causes the light to be incident on the second positive lens group. Mirror optical system.
  3. 　前記光軸偏向部材が、少なくとも１つの反射面により構成される請求項１に記載の立体視内視鏡光学系。 The stereoscopic endoscope optical system according to claim 1, wherein the optical axis deflecting member is constituted by at least one reflecting surface.
  4. 　前記第２の正のレンズ群が、一対の前記第１の正のレンズ群に対応して一対設けられている請求項１から請求項３のいずれかに記載の立体視内視鏡光学系。 The stereoscopic endoscope optical system according to any one of claims 1 to 3, wherein a pair of the second positive lens group is provided corresponding to the pair of the first positive lens groups.
  5. 　一対の前記第２の正のレンズ群を構成するレンズ対が一体的に成形されている請求項４に記載の立体視内視鏡光学系。 The stereoscopic endoscope optical system according to claim 4, wherein a pair of lenses constituting the pair of second positive lens groups is integrally formed.
  6. 　一対の前記第２の正のレンズ群が、一対の前記第１の正のレンズ群の配列方向に対して直交する方向に配列されている請求項４または請求項５に記載の立体視内視鏡光学系。 The stereoscopic internal view according to claim 4 or 5, wherein the pair of second positive lens groups are arranged in a direction orthogonal to an arrangement direction of the pair of first positive lens groups. Mirror optical system.
  7. 　一対の前記負のレンズ群あるいは、一対の前記第１の正のレンズ群を構成する左右のレンズ対が、一体的に成形されている請求項１から請求項６のいずれかに記載の立体視内視鏡光学系。 The stereoscopic view according to any one of claims 1 to 6, wherein the pair of negative lens groups or the left and right lens pairs constituting the pair of first positive lens groups are integrally formed. Endoscopic optical system.
  8. 　一対の前記負のレンズ群あるいは、一対の前記第１の正のレンズ群をそれぞれ全周にわたって遮光する筒状の遮光部材を備える請求項１から請求項７のいずれかに記載の立体視内視鏡光学系。 The stereoscopic internal view according to any one of claims 1 to 7, further comprising a cylindrical light shielding member that shields the pair of negative lens groups or the pair of first positive lens groups over the entire circumference. Mirror optical system.
  9. 　前記光軸偏向部材の内部に瞳位置が配置されている請求項１から請求項８のいずれかに記載の立体視内視鏡光学系。 The stereoscopic endoscope optical system according to any one of claims 1 to 8, wherein a pupil position is disposed inside the optical axis deflection member.
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