WO2017187814A1 - Endoscope objective optical system - Google Patents

Endoscope objective optical system Download PDF

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Publication number
WO2017187814A1
WO2017187814A1 PCT/JP2017/009657 JP2017009657W WO2017187814A1 WO 2017187814 A1 WO2017187814 A1 WO 2017187814A1 JP 2017009657 W JP2017009657 W JP 2017009657W WO 2017187814 A1 WO2017187814 A1 WO 2017187814A1
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Prior art keywords
optical system
endoscope objective
lens
objective optical
intermediate region
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PCT/JP2017/009657
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French (fr)
Japanese (ja)
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菅武志
市之瀬淳
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オリンパス株式会社
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Priority to JP2017551338A priority Critical patent/JPWO2017187814A1/en
Publication of WO2017187814A1 publication Critical patent/WO2017187814A1/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
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/11—Anti-reflection coatings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/04—Reversed telephoto objectives
    • 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
    • G02B23/26—Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes using light guides

Definitions

  • the present invention relates to an endoscope objective optical system.
  • a stereoscopic observation system uses a method of imaging two stereoscopic images with different parallaxes formed on an imaging surface of an imaging device on substantially the same plane (see, for example, Patent Documents 1 and 2). And in the structure of a prior art, in order to obtain two images with different parallax, it has two different optical systems.
  • flare may occur in the area between the two optical systems. Such flare is undesirable because it degrades the quality of the observed image.
  • the present invention has been made in view of the above, and an object thereof is to provide an endoscope objective optical system that is easy to manufacture and that can reduce flare generated between two optical systems. To do.
  • At least some embodiments of the present invention are endoscope objective optical systems used for endoscopic imaging for stereoscopic observation, and are the most object side.
  • the lens is one optical member having two concave surface portions, and is characterized in that reflected light reducing means is provided in an intermediate region between the two concave surface portions (L11, L12).
  • the present invention has an effect of providing an endoscope objective optical system that is easy to manufacture and can reduce flare generated between two optical systems.
  • FIG. 10 is a diagram illustrating a lens cross-sectional configuration of an endoscope objective optical system according to Example 2.
  • FIG. 1 is a diagram illustrating a lens cross-sectional configuration of the endoscope objective optical system according to the first embodiment.
  • This embodiment is an endoscope objective optical system used for imaging for an endoscope for stereoscopic observation, and the lens L1 on the most object side is one optical member having two concave portions, and two concave portions.
  • the present invention is characterized in that reflected light reducing means is provided in an intermediate area A between L11 and L12.
  • the optical system for stereoscopic observation is a first optical system LNS1 and a second optical system LNS2 that generate two optical images having parallax with each other.
  • the first optical system LNS1 forms an image for the right eye
  • the second optical system LNS2 forms an image for the left eye.
  • the most object side lens is a lens L1 of one optical member having two concave portions L11 and L12. Reflected light reducing means is provided in an intermediate region A between the two concave portions L11 and L12.
  • FIG. 2 is a diagram showing a front configuration of the lens L1 closest to the object side of the endoscope objective optical system according to the first embodiment.
  • the reflected light reducing means is an intermediate region A in which the two concave surface portions L11 and L12 are connected by a gently convex surface.
  • FIG. 3 is a diagram illustrating a cross-sectional configuration of the most object side lens L1 in the present embodiment.
  • FIG. 5A shows a cross-sectional configuration of the most object side lens L1 of the conventional configuration.
  • the shape between the two concave surface portions L11 and L12 has a sharp and sharp shape portion B.
  • the light ray RAY1 incident on the sharp and sharp shaped part B is totally reflected by the concave part L12, totally reflected by the concave part L11, and further reflected by a plane. As a result, flare occurs.
  • the shape between the two concave surface portions L11 and L12 has a sharp and sharp shape portion B.
  • the light ray RAY1 'incident on the sharp pointed portion B is reflected by the sharp pointed portion B and further reflected by a plane. As a result, flare occurs.
  • the sharp and sharp shape portion B even if an antireflection film is coated, total reflected light cannot be reduced. Further, the sharp and sharp shape portion B has a problem that it is easily broken during the manufacture of the lens L1.
  • the reflected light reducing means is preferably an antireflection coating applied to the intermediate region A.
  • the light ray RAY2 shown in FIG. 3 may be emitted to the image side by being reflected twice in the lens L1, and may cause flare. Such flare can be reduced by the antireflection coating.
  • the antireflection coating may be coated on the two concave portions L11 and L12 and the intermediate region A at a time. For this reason, the cost at the time of manufacture can be reduced by man-hour reduction.
  • the sphere notch depth of the intermediate region A provided with the reflected light reducing means is shallower than the sphere notch depth of the concave surface part.
  • FIG. 4 is a diagram showing a lens cross-sectional configuration of the lens L1 closest to the object side of the endoscope objective optical system. The sphere missing depth will be described.
  • the notch depth of the concave surface portion means a length dp1 between the intersection P2 of the edge portion P1 and the optical axis AX1 and the top surface position P3 of the concave surface of the concave surface portion L11.
  • the sphere notch depth of the intermediate region A refers to a length dp2 between the vertex position P4 of the intermediate region A and the position P5 corresponding to the top surface position P3 of the concave surface of the concave surface portion L11.
  • the sphere notch depth of the intermediate region A becomes shallower than the sphere notch depths of the concave surface portions L11 and L12. For this reason, flare as shown in FIG. 5A can be reduced.
  • FIG. 6 is a diagram illustrating a lens cross-sectional configuration of the endoscope objective optical system according to the second embodiment.
  • the present embodiment is an endoscope objective optical system used for endoscope imaging for stereoscopic observation, and the lens L1 closest to the object side is one optical member having two concave portions L11 and L12.
  • the optical system for stereoscopic observation is a first optical system LNS1 and a second optical system LNS2 that generate two optical images having parallax with each other.
  • the first optical system LNS1 forms an image for the right eye
  • the second optical system LNS2 forms an image for the left eye.
  • the middle of the two concave surface portions L11 and L12 has a sharp pointed shape.
  • the reflected light reducing means is a flare that is disposed on the image side of the lens L1 that is an optical member and has two openings FS1 and FS2 corresponding to the two concave surface portions L11 and L12.
  • the aperture FS, and the two openings FS1 and FS2, the length a from the edge near the intermediate region to the optical axis is preferably shorter than the length b from the other edge to the optical axis.
  • FIG. 7 is a diagram showing a front configuration of the flare stop FS.
  • the light-shielding portion is indicated by hatching.
  • Each of the two openings FS1 and FS2 has an octagonal irregular shape. As described above, the length a ⁇ length b is satisfied.
  • the two openings FS1 and FS2 are configured such that the opening diameters on the opposite sides are small.
  • the flare as shown in FIGS. 5A and 5B occurs in the region between the concave portions L11 and L12. According to the flare stop FS of this embodiment, only such flare can be effectively reduced.
  • the flare stop FS is composed of a single metal plate. Therefore, compared with the case where the flare stop is manufactured using two metal plates having one opening, in the present embodiment, no gap is generated between the openings FS1 and FS2, and therefore, more effective. Flare can be reduced. In addition, since the flare stop FS is composed of a single metal plate, assembly during manufacture is easy.
  • FIG. 8A is a diagram showing the right-eye image brightness distribution.
  • FIG. 8B is a diagram showing the left-eye image brightness distribution.
  • LNS1 right eye image
  • LNS2 left eye image
  • FIG. 9 is a diagram showing a schematic configuration of an endoscope system having an endoscope objective optical system according to the present embodiment.
  • a shading correction unit 103 is provided in the image processing apparatus 102.
  • a signal from the image sensor IMG is input to the image processing apparatus 102 via the A / D conversion unit 101.
  • the shading correction unit 103 corrects the brightness distribution with an odd or higher order function in the parallax direction. Accordingly, the screen can be observed with uniform brightness on the display unit 104. Further, since shading correction is performed only in a specific direction, image quality deterioration (noise increase due to gain) accompanying correction can be minimized.
  • the opening shape of the flare stop FS is rotationally symmetric, it is necessary to reduce the opening diameter in all directions from the viewpoint of flare countermeasures. In this case, it is necessary to increase the image gain in the peripheral part in all directions for both the left eye image and the right eye image. Therefore, the image has a poor S / N compared to the present embodiment.
  • the flare can be further effectively reduced by using the flare stop FS described in the second embodiment.
  • FIG. 10 is a diagram illustrating a lens cross-sectional configuration of the endoscope optical system according to the present embodiment.
  • the present embodiment has a first optical system LNS1 and a second optical system LNS2 that generate two optical images having parallax with each other.
  • Each optical system includes, in order from the object side, a plano-concave negative lens L1 having a concave surface on the image side, a negative meniscus lens L2 having a convex surface on the image side, a parallel plate F1, an aperture stop S,
  • the lens includes a convex positive lens L3, a biconvex positive lens L4, a negative meniscus lens L5 having a convex surface on the image side, a plano-convex positive lens L6 having a convex surface on the object side, and a parallel plate CG.
  • the planoconvex positive lens L6 is a field lens. Thereby, focus adjustment accuracy can be relaxed.
  • FIG. 11 is a diagram illustrating a lens cross-sectional configuration of the endoscope optical system according to the present embodiment.
  • the lens data is the same as in Example 1 except that a flare stop FS is provided on the image side surface of the lens L1.
  • r are the radii of curvature of the lens surfaces
  • d is the spacing between the lens surfaces
  • nd is the refractive index of the d-line of each lens
  • ⁇ d is the Abbe number of each lens.
  • S is an aperture stop
  • FS is a flare stop.
  • the present invention is not limited to these embodiments, and may be implemented by appropriately combining the configurations of these embodiments without departing from the spirit of the present invention.
  • the form is also within the scope of the present invention.
  • the optical system is not limited to the single focus optical system of the present embodiment, and can also be applied to a zoom optical system.
  • the present embodiment has two optical systems, but the present invention is not limited to this. There are three or more optical systems, and images of any two of these optical systems are selected for stereoscopic observation. It may be configured to. In that case, the optical member and reflected light reducing means of this embodiment may be applied to the two optical systems with the shortest parallax.
  • the two optical systems have individual lenses, but the lens on the image side of L1 is used as a common lens (one concave or convex lens) for the two optical systems. It may be deformed. Further, an anti-reflection coating may be added to the flat portion on the object side of L1 (surface number 1 in the numerical example) to further reduce flare.
  • the present invention is easy to manufacture and is useful for an endoscope objective optical system that can reduce flare generated between two optical systems.
  • LNS1 First optical system LNS2 Second optical system AX1, AX2 Optical axis IMG Imaging element I Image plane (imaging plane) L11, L12 Concave portion L1-L6 Lens F1, F2, CG Parallel plate S Brightness stop FS Flare stop A Middle area B Sharp pointed shape

Abstract

The present invention addresses the problem of providing an endoscope objective optical system having a configuration that is easy to produce, and is capable of reducing flare generated between the two optical systems used for acquiring two images with different disparities for 3D viewing. The endoscope objective optical system according to the present invention is used in endoscopic imaging for 3D observation. A lens L1 closest to an object is an optical member having two concave surfaces. A reflection light attenuation means is provided in an intermediate region located between two concave surfaces L11, L12.

Description

内視鏡対物光学系Endoscope objective optical system
　本発明は、内視鏡対物光学系に関するものである。 The present invention relates to an endoscope objective optical system.
　従来、立体観察システムが知られている。立体観察システムは、立体視用に視差の異なる２つの画像を略同一の平面上の撮像素子の撮像面に結像させて撮像する方法を用いている（例えば、特許文献１、２参照）。そして、従来技術の構成では、視差の異なる２つの画像を得るために、２つの異なる光学系を有している。 Conventionally, a stereoscopic observation system is known. The stereoscopic observation system uses a method of imaging two stereoscopic images with different parallaxes formed on an imaging surface of an imaging device on substantially the same plane (see, for example, Patent Documents 1 and 2). And in the structure of a prior art, in order to obtain two images with different parallax, it has two different optical systems.
国際公開第２０１３－１０８５００号International Publication No. 2013-108500 特開平１１－６９６７号公報Japanese Patent Laid-Open No. 11-6967
　技術の構成では、２つの光学系の間の領域においてフレアが発生することがある。このようなフレアは、観察画像の質を劣化させるため好ましくない。 In the technology configuration, flare may occur in the area between the two optical systems. Such flare is undesirable because it degrades the quality of the observed image.
　本発明は、上記に鑑みてなされたものであって、製造が容易な構成であって、２つの光学系の間において発生するフレアを低減できる内視鏡対物光学系を提供することを目的とする。 The present invention has been made in view of the above, and an object thereof is to provide an endoscope objective optical system that is easy to manufacture and that can reduce flare generated between two optical systems. To do.
　上述した課題を解決し、目的を達成するために、本発明の少なくとも幾つかの実施形態は、立体観察用の内視鏡用撮像に使用する内視鏡対物光学系であり、最も物体側のレンズは２つの凹面部を有する１つの光学部材であり、２つの凹面部（Ｌ１１、Ｌ１２）の中間領域に反射光低減手段を設けたことを特徴とする。 In order to solve the above-described problems and achieve the object, at least some embodiments of the present invention are endoscope objective optical systems used for endoscopic imaging for stereoscopic observation, and are the most object side. The lens is one optical member having two concave surface portions, and is characterized in that reflected light reducing means is provided in an intermediate region between the two concave surface portions (L11, L12).
　本発明は、製造が容易な構成であって、２つの光学系の間において発生するフレアを低減できる内視鏡対物光学系を提供できるという効果を奏する。 The present invention has an effect of providing an endoscope objective optical system that is easy to manufacture and can reduce flare generated between two optical systems.
第１実施形態に係る内視鏡対物光学系のレンズ断面構成を示す図である。It is a figure which shows the lens cross-section structure of the endoscope objective optical system which concerns on 1st Embodiment. 第１実施形態に係る内視鏡対物光学系の最も物体側のレンズの正面構成を示す図である。It is a figure which shows the front structure of the lens of the most object side of the endoscope objective optical system which concerns on 1st Embodiment. 第１実施形態に係る内視鏡対物光学系の最も物体側のレンズ断面構成を示す図である。It is a figure which shows the lens cross-section structure of the most object side of the endoscope objective optical system which concerns on 1st Embodiment. 第１実施形態に係る内視鏡対物光学系の最も物体側のレンズ断面構成を示す他の図である。It is another figure which shows the lens cross-sectional structure of the most object side of the endoscope objective optical system which concerns on 1st Embodiment. （ａ）、（ｂ）は、内視鏡対物光学系の最も物体側のレンズで発生するフレアを示す図である。(A), (b) is a figure which shows the flare which generate | occur | produces with the lens of the most object side of an endoscope objective optical system. 第２実施形態に係る内視鏡対物光学系のレンズ断面構成を示す図である。It is a figure which shows the lens cross-section structure of the endoscope objective optical system which concerns on 2nd Embodiment. 第２実施形態に係る内視鏡対物光学系のフレア絞りの正面構成を示す図である。It is a figure which shows the front structure of the flare stop of the endoscope objective optical system which concerns on 2nd Embodiment. （ａ）、（ｂ）は、それぞれ第２実施形態に係る内視鏡対物光学系の右目画像、左目画像の明るさ分布を示す図である。(A), (b) is a figure which shows the brightness distribution of the right-eye image of the endoscope objective optical system which concerns on 2nd Embodiment, and a left-eye image, respectively. 第２実施形態に係る内視鏡対物光学系を有する内視鏡システムの概略構成を示す図である。It is a figure which shows schematic structure of the endoscope system which has an endoscope objective optical system which concerns on 2nd Embodiment. 実施例１に係る内視鏡対物光学系のレンズ断面構成を示す図である。It is a figure which shows the lens cross-section structure of the endoscope objective optical system which concerns on Example 1. FIG. 実施例２に係る内視鏡対物光学系のレンズ断面構成を示す図である。FIG. 10 is a diagram illustrating a lens cross-sectional configuration of an endoscope objective optical system according to Example 2.
　以下に、実施形態に係る内視鏡対物光学系を図面に基づいて詳細に説明する。なお、この実施形態により、この発明が限定されるものではない。 Hereinafter, an endoscope objective optical system according to an embodiment will be described in detail based on the drawings. In addition, this invention is not limited by this embodiment.
（第１実施形態）
　図１は、第１実施形態に係る内視鏡対物光学系のレンズ断面構成を示す図である。本実施形態は、立体観察用の内視鏡用撮像に使用する内視鏡対物光学系であり、最も物体側のレンズＬ１は２つの凹面部を有する１つの光学部材であり、２つの凹面部Ｌ１１、Ｌ１２の中間領域Ａに反射光低減手段を設けたことを特徴とする。 (First embodiment)
FIG. 1 is a diagram illustrating a lens cross-sectional configuration of the endoscope objective optical system according to the first embodiment. This embodiment is an endoscope objective optical system used for imaging for an endoscope for stereoscopic observation, and the lens L1 on the most object side is one optical member having two concave portions, and two concave portions. The present invention is characterized in that reflected light reducing means is provided in an intermediate area A between L11 and L12.
　立体観察用の光学系は、互いに視差を有する２つの光学像を生成する、第１の光学系ＬＮＳ１と第２の光学系ＬＮＳ２である。例えば、第１の光学系ＬＮＳ１は右目用の画像を結像し、第２の光学系ＬＮＳ２は左目用の画像を結像する。 The optical system for stereoscopic observation is a first optical system LNS1 and a second optical system LNS2 that generate two optical images having parallax with each other. For example, the first optical system LNS1 forms an image for the right eye, and the second optical system LNS2 forms an image for the left eye.
　最も物体側のレンズは２つの凹面部Ｌ１１、Ｌ１２を有する１つの光学部材のレンズＬ１である。２つの凹面部Ｌ１１、Ｌ１２の中間領域Ａに反射光低減手段が設けられている。 The most object side lens is a lens L1 of one optical member having two concave portions L11 and L12. Reflected light reducing means is provided in an intermediate region A between the two concave portions L11 and L12.
　図２は、第１実施形態に係る内視鏡対物光学系の最も物体側のレンズＬ１の正面構成を示す図である。 FIG. 2 is a diagram showing a front configuration of the lens L1 closest to the object side of the endoscope objective optical system according to the first embodiment.
　また、本実施形態の好ましい態様によれば、反射光低減手段は、２つの凹面部Ｌ１１、Ｌ１２をなだらかな凸形状の面で接続した中間領域Ａであることが望ましい。 Further, according to a preferred aspect of the present embodiment, it is desirable that the reflected light reducing means is an intermediate region A in which the two concave surface portions L11 and L12 are connected by a gently convex surface.
　図３は、本実施形態における、最も物体側のレンズＬ１の断面構成を示す図である。本実施形態と対比するため、図５（ａ）に従来構成の最も物体側のレンズＬ１の断面構成を示す。 FIG. 3 is a diagram illustrating a cross-sectional configuration of the most object side lens L1 in the present embodiment. For comparison with the present embodiment, FIG. 5A shows a cross-sectional configuration of the most object side lens L1 of the conventional configuration.
　図５（ａ）に示す構成では、２つの凹面部Ｌ１１、Ｌ１２の間の形状は、尖った鋭利な形状部Ｂを有している。尖った鋭利な形状部Ｂに入射した光線ＲＡＹ１は、凹面部Ｌ１２で全反射し、凹面部Ｌ１１で全反射し、さらに平面で反射する。これにより、フレアを生じてしまう。 In the configuration shown in FIG. 5A, the shape between the two concave surface portions L11 and L12 has a sharp and sharp shape portion B. The light ray RAY1 incident on the sharp and sharp shaped part B is totally reflected by the concave part L12, totally reflected by the concave part L11, and further reflected by a plane. As a result, flare occurs.
　図５（ｂ）に示す構成では、２つの凹面部Ｌ１１、Ｌ１２の間の形状は、尖った鋭利な形状部Ｂを有している。尖った鋭利な形状部Ｂに入射した光線ＲＡＹ１’は、尖った鋭利な形状部Ｂで反射し、さらに平面で反射する。これにより、フレアを生じてしまう。 In the configuration shown in FIG. 5B, the shape between the two concave surface portions L11 and L12 has a sharp and sharp shape portion B. The light ray RAY1 'incident on the sharp pointed portion B is reflected by the sharp pointed portion B and further reflected by a plane. As a result, flare occurs.
　尖った鋭利な形状部Ｂでは、反射防止膜をコーティングしても、全反射光を低減できない。また、尖った鋭利な形状部Ｂは、レンズＬ１の製造時に割れやすいという問題も有している。 In the sharp and sharp shape portion B, even if an antireflection film is coated, total reflected light cannot be reduced. Further, the sharp and sharp shape portion B has a problem that it is easily broken during the manufacture of the lens L1.
　ここで、本実施形態の好ましい態様によれば、反射光低減手段は、中間領域Ａに施した反射防止コートであることが好ましい。なだらかな凸形状の中間領域Ａであっても、図３に示す光線ＲＡＹ２は、レンズＬ１内で２回反射することで像側へ射出してしまい、フレアを生ずることがある。反射防止コートにより、このようなフレアを低減できる。 Here, according to a preferred aspect of the present embodiment, the reflected light reducing means is preferably an antireflection coating applied to the intermediate region A. Even in the gently convex intermediate region A, the light ray RAY2 shown in FIG. 3 may be emitted to the image side by being reflected twice in the lens L1, and may cause flare. Such flare can be reduced by the antireflection coating.
　これにより、中間領域Ａにおいて反射し、平面で反射する光量を低減できるため、フレアを低減できる。 This makes it possible to reduce the amount of light reflected at the intermediate area A and reflected by a flat surface, thereby reducing flare.
　反射防止コートは、中間領域Ａだけでなく、２つの凹面部Ｌ１１、Ｌ１２の有効範囲に施すことが好ましい。これにより、２つの凹面部Ｌ１１、Ｌ１２と中間領域Ａとに一度に反射防止コートをコーティングすれば良い。このため、工数削減により、製造時のコストを低減できる。 It is preferable to apply the antireflection coating not only to the intermediate region A but also to the effective range of the two concave portions L11 and L12. Accordingly, the antireflection coat may be coated on the two concave portions L11 and L12 and the intermediate region A at a time. For this reason, the cost at the time of manufacture can be reduced by man-hour reduction.
　また、本実施形態の好ましい態様によれば、反射光低減手段を設けた中間領域Ａの球欠深さは、凹面部の球欠深さよりも浅いことが望ましい。 Further, according to a preferred aspect of the present embodiment, it is desirable that the sphere notch depth of the intermediate region A provided with the reflected light reducing means is shallower than the sphere notch depth of the concave surface part.
　図４は、内視鏡対物光学系の最も物体側のレンズＬ１のレンズ断面構成を示す図である。球欠深さについて説明する。 FIG. 4 is a diagram showing a lens cross-sectional configuration of the lens L1 closest to the object side of the endoscope objective optical system. The sphere missing depth will be described.
　凹面部の球欠深さとは、縁部Ｐ１と光軸ＡＸ１との交点Ｐ２と、凹面部Ｌ１１の凹面の面頂位置Ｐ３と、の間の長さｄｐ１をいう。また、中間領域Ａの球欠深さとは、中間領域Ａの頂点位置Ｐ４と、凹面部Ｌ１１の凹面の面頂位置Ｐ３に対応する位置Ｐ５と、の間の長さｄｐ２をいう。 The notch depth of the concave surface portion means a length dp1 between the intersection P2 of the edge portion P1 and the optical axis AX1 and the top surface position P3 of the concave surface of the concave surface portion L11. Further, the sphere notch depth of the intermediate region A refers to a length dp2 between the vertex position P4 of the intermediate region A and the position P5 corresponding to the top surface position P3 of the concave surface of the concave surface portion L11.
　そして、ｄｐ１＞ｄｐ２であることが望ましい。これにより、中間領域Ａの球欠深さが、凹面部Ｌ１１、Ｌ１２の球欠深さよりも浅くなる。このため、図５（ａ）で示すような、フレアを低減できる。 And it is desirable that dp1> dp2. As a result, the sphere notch depth of the intermediate region A becomes shallower than the sphere notch depths of the concave surface portions L11 and L12. For this reason, flare as shown in FIG. 5A can be reduced.
（第２実施形態）
　図６は、第２実施形態に係る内視鏡対物光学系のレンズ断面構成を示す図である。本実施形態は、立体観察用の内視鏡用撮像に使用する内視鏡対物光学系であり、最も物体側のレンズＬ１は２つの凹面部Ｌ１１、Ｌ１２を有する１つの光学部材である。 (Second Embodiment)
FIG. 6 is a diagram illustrating a lens cross-sectional configuration of the endoscope objective optical system according to the second embodiment. The present embodiment is an endoscope objective optical system used for endoscope imaging for stereoscopic observation, and the lens L1 closest to the object side is one optical member having two concave portions L11 and L12.
　立体観察用の光学系は、互いに視差を有する２つの光学像を生成する、第１の光学系ＬＮＳ１と第２の光学系ＬＮＳ２である。例えば、第１の光学系ＬＮＳ１は右目用の画像を結像し、第２の光学系ＬＮＳ２は左目用の画像を結像する。 The optical system for stereoscopic observation is a first optical system LNS1 and a second optical system LNS2 that generate two optical images having parallax with each other. For example, the first optical system LNS1 forms an image for the right eye, and the second optical system LNS2 forms an image for the left eye.
　２つの凹面部Ｌ１１、Ｌ１２の中間は、尖った鋭利な形状を有している。 The middle of the two concave surface portions L11 and L12 has a sharp pointed shape.
　そして、本実施形態の好ましい態様によれば、反射光低減手段は、光学部材であるレンズＬ１の像側に配置され、２つの凹面部Ｌ１１、Ｌ１２に対応する２つの開口ＦＳ１、ＦＳ２を有するフレア絞りＦＳであり、２つの開口ＦＳ１、ＦＳ２は、中間領域付近の縁から光軸までの長さａが、その他の部分の縁から光軸までの長さｂより短いことが望ましい。 And according to the preferable aspect of this embodiment, the reflected light reducing means is a flare that is disposed on the image side of the lens L1 that is an optical member and has two openings FS1 and FS2 corresponding to the two concave surface portions L11 and L12. The aperture FS, and the two openings FS1 and FS2, the length a from the edge near the intermediate region to the optical axis is preferably shorter than the length b from the other edge to the optical axis.
　図７は、フレア絞りＦＳの正面構成を示す図である。遮光部分は、斜線を付して示す。２つの開口ＦＳ１、ＦＳ２は、それぞれ８角形の異形開口形状を有している。そして、上述したように、長さａ＜長さｂを満足している。 FIG. 7 is a diagram showing a front configuration of the flare stop FS. The light-shielding portion is indicated by hatching. Each of the two openings FS1 and FS2 has an octagonal irregular shape. As described above, the length a <length b is satisfied.
　換言すると、２つの開口ＦＳ１、ＦＳ２は、対向する側の開口径が小さく構成されている。本実施形態では、図５（ａ）、（ｂ）で示すようなフレアは、凹面部Ｌ１１、Ｌ１２の間の領域で発生する。本実施形態のフレア絞りＦＳによれば、このようなフレアのみを効果的に低減できる。 In other words, the two openings FS1 and FS2 are configured such that the opening diameters on the opposite sides are small. In the present embodiment, the flare as shown in FIGS. 5A and 5B occurs in the region between the concave portions L11 and L12. According to the flare stop FS of this embodiment, only such flare can be effectively reduced.
　またフレア絞りＦＳは、１枚の金属板で構成することが望ましい。これにより、１つの開口を有する１枚の金属板を２枚使用してフレア絞りを製造する場合に比較して、本実施形態では、開口ＦＳ１、ＦＳ２の間に隙間を生じないため、より効果的にフレアを低減できる。また、フレア絞りＦＳを１枚の金属板で構成するため、製造時の組立も容易である。 Also, it is desirable that the flare stop FS is composed of a single metal plate. Thereby, compared with the case where the flare stop is manufactured using two metal plates having one opening, in the present embodiment, no gap is generated between the openings FS1 and FS2, and therefore, more effective. Flare can be reduced. In addition, since the flare stop FS is composed of a single metal plate, assembly during manufacture is easy.
　本実施形態では、フレア絞りＦＳの視差方向の開口径が小さい。このため、得られる画像の明るさ分布は、図８（ａ）、（ｂ）のようになる。図８（ａ）は、右目画像明るさ分布を示す図である。図８（ｂ）は、左目画像明るさ分布を示す図である。このように、視差方向の片側だけが暗くなる。暗くなる方向は右目画像（ＬＮＳ１）、左目画像（ＬＮＳ２）で逆になる。このため、左右画像で明るさが異なるという問題が発生する。 In this embodiment, the opening diameter in the parallax direction of the flare stop FS is small. For this reason, the brightness distribution of the obtained image is as shown in FIGS. FIG. 8A is a diagram showing the right-eye image brightness distribution. FIG. 8B is a diagram showing the left-eye image brightness distribution. Thus, only one side in the parallax direction becomes dark. The direction of darkness is reversed between the right eye image (LNS1) and the left eye image (LNS2). This causes a problem that the brightness differs between the left and right images.
　図９は、本実施形態に係る内視鏡対物光学系を有する内視鏡システムの概略構成を示す図である。本実施形態では、図９に示すように、画像処理装置１０２内にシェーディング補正部１０３を設けている。撮像素子ＩＭＧからの信号は、Ａ／Ｄ変換部１０１を介して画像処理装置１０２に入力される。 FIG. 9 is a diagram showing a schematic configuration of an endoscope system having an endoscope objective optical system according to the present embodiment. In this embodiment, as shown in FIG. 9, a shading correction unit 103 is provided in the image processing apparatus 102. A signal from the image sensor IMG is input to the image processing apparatus 102 via the A / D conversion unit 101.
　シェーディング補正部１０３は、視差方向に３次以上の奇関数で明るさ分布を補正する。これにより、表示部１０４において、画面が均一の明るさで観察できる。また、特定の方向だけにシェーディング補正を行うため、補正に伴う画質劣化（ゲインによるノイズ増）は最小限にできる。 The shading correction unit 103 corrects the brightness distribution with an odd or higher order function in the parallax direction. Accordingly, the screen can be observed with uniform brightness on the display unit 104. Further, since shading correction is performed only in a specific direction, image quality deterioration (noise increase due to gain) accompanying correction can be minimized.
　仮に、フレア絞りＦＳの開口形状を回転対称にすると、フレア対策の観点で、全方向で開口径を小さくする必要がある。その場合、左目画像、右目画像とも全方向の周辺部の画像ゲインを上げる必要が生ずる。よって、本実施形態に比べて、Ｓ／Ｎが悪い画像となってしまう。 If the opening shape of the flare stop FS is rotationally symmetric, it is necessary to reduce the opening diameter in all directions from the viewpoint of flare countermeasures. In this case, it is necessary to increase the image gain in the peripheral part in all directions for both the left eye image and the right eye image. Therefore, the image has a poor S / N compared to the present embodiment.
　なお、上記第１実施形態の構成において、第２実施形態で述べたフレア絞りＦＳを用いることで、さらの効果的にフレアを低減できる。 In the configuration of the first embodiment, the flare can be further effectively reduced by using the flare stop FS described in the second embodiment.
（実施例１）
　実施例１に係る内視鏡光学系について説明する。図１０は、本実施例に係る内視鏡光学系のレンズ断面構成を示す図である。 Example 1
An endoscope optical system according to Example 1 will be described. FIG. 10 is a diagram illustrating a lens cross-sectional configuration of the endoscope optical system according to the present embodiment.
　本実施例は、互いに視差を有する２つの光学像を生成する、第１の光学系ＬＮＳ１と、第２の光学系ＬＮＳ２と、を有する。それぞれの光学系は、物体側から順に、像側に凹面を向けた平凹負レンズＬ１と、像側に凸面を向けた負メニスカスレンズＬ２と、平行平板Ｆ１と、明るさ絞りＳと、両凸正レンズＬ３と、両凸正レンズＬ４と、像側に凸面を向けた負メニスカスレンズＬ５と、物体側に凸面を向けた平凸正レンズＬ６と、平行平板ＣＧと、から構成される。 The present embodiment has a first optical system LNS1 and a second optical system LNS2 that generate two optical images having parallax with each other. Each optical system includes, in order from the object side, a plano-concave negative lens L1 having a concave surface on the image side, a negative meniscus lens L2 having a convex surface on the image side, a parallel plate F1, an aperture stop S, The lens includes a convex positive lens L3, a biconvex positive lens L4, a negative meniscus lens L5 having a convex surface on the image side, a plano-convex positive lens L6 having a convex surface on the object side, and a parallel plate CG.
　平凸正レンズＬ６は、フィールドレンズである。これにより、ピント調整精度を緩和できる。 The planoconvex positive lens L6 is a field lens. Thereby, focus adjustment accuracy can be relaxed.
（実施例２）
　実施例２に係る内視鏡光学系について説明する。図１１は、本実施例に係る内視鏡光学系のレンズ断面構成を示す図である。レンズＬ１の像側面にフレア絞りＦＳを設けた点を除いて、レンズデータは実施例１と同じである。 (Example 2)
An endoscope optical system according to Example 2 will be described. FIG. 11 is a diagram illustrating a lens cross-sectional configuration of the endoscope optical system according to the present embodiment. The lens data is the same as in Example 1 except that a flare stop FS is provided on the image side surface of the lens L1.
　以下に、上記各実施例の数値データを示す。記号は、ｒは各レンズ面の曲率半径、ｄは各レンズ面間の間隔、ｎｄは各レンズのｄ線の屈折率、νｄは各レンズのアッベ数である。また、Ｓは明るさ絞り、ＦＳはフレア絞りである。 The numerical data of each of the above examples is shown below. Symbols r are the radii of curvature of the lens surfaces, d is the spacing between the lens surfaces, nd is the refractive index of the d-line of each lens, and νd is the Abbe number of each lens. Further, S is an aperture stop, and FS is a flare stop.
数値実施例１
単位  ｍｍ
 
面データ
  面番号            r         d          nd       νd
    1               ∞       0.2500    1.88815    40.76    
    2              0.5920    0.5400        
    3             -2.6449    0.8360    1.85504    23.78    
    4             -2.8388    0.1900         
    5               ∞       0.4000    1.49557    75.00    
    6               ∞       0.0807         
    7(S)            ∞       0.1338         
    8              3.6829    0.6446    1.83932    37.16    
    9             -2.2104    0.3395        
    10             1.5521    0.7800    1.69979    55.53    
    11            -0.8302    0.3523    1.93429    18.90    
    12           -35.2793    0.3040       
    13             1.5026    0.5000    1.51825    64.14    
    14              ∞       0.3500    1.50700    63.26    
撮像面              ∞ 
 
　全系焦点距離ｆ１         0.41769 
　視差  １．１ｍｍ
 
球欠深さ
 ｄｐ１＝０．３７
 ｄｐ２＝０．２６ Numerical example 1
Unit mm

Surface data Surface number r d nd νd
1 ∞ 0.2500 1.88815 40.76
2 0.5920 0.5400
3 -2.6449 0.8360 1.85504 23.78
4 -2.8388 0.1900
5 ∞ 0.4000 1.49557 75.00
6 ∞ 0.0807
7 (S) ∞ 0.1338
8 3.6829 0.6446 1.83932 37.16
9 -2.2104 0.3395
10 1.5521 0.7800 1.69979 55.53
11 -0.8302 0.3523 1.93429 18.90
12 -35.2793 0.3040
13 1.5026 0.5000 1.51825 64.14
14 ∞ 0.3500 1.50700 63.26
Imaging surface ∞

Total focal length f1 0.41769
Parallax 1.1mm

Sphere missing depth dp1 = 0.37
dp2 = 0.26
数値実施例2
単位  ｍｍ
 
面データ
  面番号            r         d          nd       νd
    1               ∞       0.2500    1.88815    40.76    
    2              0.5920    0.3700        
    3(FS)          ∞        0.1700
    4             -2.6449    0.8360    1.85504    23.78    
    5             -2.8388    0.1900         
    6               ∞       0.4000    1.49557    75.00    
    7               ∞       0.0807         
    8(S)            ∞       0.1338         
    9              3.6829    0.6446    1.83932    37.16    
    10            -2.2104    0.3395        
    11             1.5521    0.7800    1.69979    55.53    
    12            -0.8302    0.3523    1.93429    18.90    
    13           -35.2793    0.3040       
    14             1.5026    0.5000    1.51825    64.14    
    15              ∞       0.3500    1.50700    63.26    
撮像面              ∞ 
 
　全系焦点距離ｆ１         0.41769 
　視差  １．１ｍｍ
 
　フレア絞りＦＳのパラメータ
　長さａ＝０．４０ｍｍ
　長さｂ＝０．４５ｍｍ
  Numerical example 2
Unit mm

Surface data Surface number r d nd νd
1 ∞ 0.2500 1.88815 40.76
2 0.5920 0.3700
3 (FS) ∞ 0.1700
4 -2.6449 0.8360 1.85504 23.78
5 -2.8388 0.1900
6 ∞ 0.4000 1.49557 75.00
7 ∞ 0.0807
8 (S) ∞ 0.1338
9 3.6829 0.6446 1.83932 37.16
10 -2.2104 0.3395
11 1.5521 0.7800 1.69979 55.53
12 -0.8302 0.3523 1.93429 18.90
13 -35.2793 0.3040
14 1.5026 0.5000 1.51825 64.14
15 ∞ 0.3500 1.50700 63.26
Imaging surface ∞

Total focal length f1 0.41769
Parallax 1.1mm

Parameters of flare stop FS Length a = 0.40mm
Length b = 0.45mm
　以上、本発明の種々の実施形態について説明したが、本発明は、これらの実施形態のみに限られるものではなく、その趣旨を逸脱しない範囲で、これら実施形態の構成を適宜組合せて構成した実施形態も本発明の範疇となるものである。例えば、光学系は本実施例の単焦点光学系に限られるものではなく、ズーム光学系などにも適用可能である。また、本実施例は、２つの光学系を有しているが、それに限られるものではなく、３つ以上の光学系を有し、そのうち任意の２つの光学系の画像を選択するし立体観察する構成であってもよい。その場合、視差が最も短い２つの光学系において、本実施例の光学部材、反射光低減手段を適用すればよい。また、本実施例は２つの光学系で個別のレンズを有する構成としているが、Ｌ１よりも像側のレンズを、２つの光学系で共通のレンズ（１つの凹、又は凸形状のレンズ）に変形しても良い。また、Ｌ１の物体側の平面部（数値実施例の面番号１）に反射防止コートを追加し、更なるフレア低減を行っても良い。 Although various embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and may be implemented by appropriately combining the configurations of these embodiments without departing from the spirit of the present invention. The form is also within the scope of the present invention. For example, the optical system is not limited to the single focus optical system of the present embodiment, and can also be applied to a zoom optical system. In addition, the present embodiment has two optical systems, but the present invention is not limited to this. There are three or more optical systems, and images of any two of these optical systems are selected for stereoscopic observation. It may be configured to. In that case, the optical member and reflected light reducing means of this embodiment may be applied to the two optical systems with the shortest parallax. In this embodiment, the two optical systems have individual lenses, but the lens on the image side of L1 is used as a common lens (one concave or convex lens) for the two optical systems. It may be deformed. Further, an anti-reflection coating may be added to the flat portion on the object side of L1 (surface number 1 in the numerical example) to further reduce flare.
　以上のように、本発明は、製造が容易な構成であって、２つの光学系の間において発生するフレアを低減できる内視鏡対物光学系に有用である。 As described above, the present invention is easy to manufacture and is useful for an endoscope objective optical system that can reduce flare generated between two optical systems.
　ＬＮＳ１　第１の光学系
　ＬＮＳ２　第２の光学系
　ＡＸ１、ＡＸ２　光軸
　ＩＭＧ　撮像素子
　Ｉ　像面（撮像面）　
　Ｌ１１、Ｌ１２　凹面部
　Ｌ１～Ｌ６　レンズ
　Ｆ１、Ｆ２、ＣＧ　平行平板
　Ｓ　明るさ絞り
　ＦＳ　フレア絞り
　Ａ　中間領域
　Ｂ　尖った鋭利な形状部 LNS1 First optical system LNS2 Second optical system AX1, AX2 Optical axis IMG Imaging element I Image plane (imaging plane)
L11, L12 Concave portion L1-L6 Lens F1, F2, CG Parallel plate S Brightness stop FS Flare stop A Middle area B Sharp pointed shape

Claims (5)

  1. 　立体観察用の内視鏡用撮像に使用する内視鏡対物光学系であり、
    　最も物体側のレンズは２つの凹面部を有する１つの光学部材であり、
    　前記２つの凹面部の中間領域に反射光低減手段を設けたことを特徴とする内視鏡対物光学系。     An endoscope objective optical system used for imaging for an endoscope for stereoscopic observation,
    The most object side lens is one optical member having two concave portions,
    An endoscope objective optical system, characterized in that reflected light reducing means is provided in an intermediate region between the two concave surface portions.
  2. 　前記反射光低減手段は、前記２つの凹面部をなだらかな凸形状の面で接続した前記中間領域であることを特徴とする請求項１に記載の内視鏡対物光学系。 2. The endoscope objective optical system according to claim 1, wherein the reflected light reducing means is the intermediate region in which the two concave surface portions are connected by a gently convex surface.
  3. 　前記反射光低減手段は、前記中間領域に施した反射防止コートであることを特徴とする請求項１または２に記載の内視鏡対物光学系。 The endoscope objective optical system according to claim 1 or 2, wherein the reflected light reducing means is an antireflection coating applied to the intermediate region.
  4. 　前記反射光低減手段を設けた前記中間領域の球欠深さは、前記凹面部の球欠深さよりも浅いことを特徴とする請求項１～３のいずれか一項に記載の内視鏡対物光学系。 The endoscope objective according to any one of claims 1 to 3, wherein a sphere notch depth of the intermediate region provided with the reflected light reducing means is shallower than a sphere notch depth of the concave surface part. Optical system.
  5. 　前記反射光低減手段は、前記光学部材の像側に配置され、前記２つの凹面部に対応する２つの開口を有するフレア絞りであり、
    　前記２つの開口は、前記中間領域付近の縁から光軸までの長さが、その他の部分の縁から光軸までの長さより短いことを特徴とする請求項１に記載の内視鏡対物光学系。
          The reflected light reducing means is a flare stop disposed on the image side of the optical member and having two openings corresponding to the two concave surface portions,
    2. The endoscope objective optical according to claim 1, wherein the length of the two openings from the edge near the intermediate region to the optical axis is shorter than the length from the edge of the other part to the optical axis. system.
PCT/JP2017/009657 2016-04-25 2017-03-10 Endoscope objective optical system WO2017187814A1 (en)

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PCT/JP2017/009657 WO2017187814A1 (en) 2016-04-25 2017-03-10 Endoscope objective optical system

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Citations (5)

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JP2003005096A (en) * 2001-06-27 2003-01-08 Olympus Optical Co Ltd Endoscopic apparatus
JP2003169775A (en) * 2001-12-06 2003-06-17 Olympus Optical Co Ltd Electronic endoscope
WO2013108500A1 (en) * 2012-01-18 2013-07-25 オリンパスメディカルシステムズ株式会社 Stereoscopic endoscope optical assembly
WO2014147856A1 (en) * 2013-03-22 2014-09-25 オリンパス株式会社 Optical system for three-dimensional imaging, device for three-dimensional imaging, and endoscope
WO2015107733A1 (en) * 2014-01-15 2015-07-23 オリンパス株式会社 Optical system, stereoscopic image pickup device, and endoscope

Family Cites Families (1)

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JP2002357701A (en) * 2001-06-01 2002-12-13 Ricoh Co Ltd Compound scanning lens

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003005096A (en) * 2001-06-27 2003-01-08 Olympus Optical Co Ltd Endoscopic apparatus
JP2003169775A (en) * 2001-12-06 2003-06-17 Olympus Optical Co Ltd Electronic endoscope
WO2013108500A1 (en) * 2012-01-18 2013-07-25 オリンパスメディカルシステムズ株式会社 Stereoscopic endoscope optical assembly
WO2014147856A1 (en) * 2013-03-22 2014-09-25 オリンパス株式会社 Optical system for three-dimensional imaging, device for three-dimensional imaging, and endoscope
WO2015107733A1 (en) * 2014-01-15 2015-07-23 オリンパス株式会社 Optical system, stereoscopic image pickup device, and endoscope

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