JPH08220449A - Stereoscopic vision endoscope - Google Patents

Abstract

PURPOSE: To provide a stereoscopic vision endoscope capable of making the spread of an optical path after division small and making the arranged space of a secondary optical system small. CONSTITUTION: This endoscope is provided with an insertion part 1 and an observation part 2, and an objective lens system 11 forming the image of an object, a 1st relay lens system 12 transmitting the image formed by the lens system 11, and a 2nd relay lens system 13 forming an exit pupil are arranged inside the insertion part 1. A pair of pupil division prisms 70 and 71 and a pair of secondary optical systems 30a and 30b receiving divided luminous fluxes are arranged in the observation part 2. The secondary optical systems 30a and 30b are constituted of image-formation lens systems 32a and 32b and image receiving elements 34a and 34b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stereoscopic endoscope for stereoscopically observing and photographing an object.

[0002]

2. Description of the Related Art A stereoscopic endoscope divides an image transmitted by this primary optical system into a left and right primary optical system including an objective lens system for forming an object image and a relay lens system for transmitting this image. Industry for observing the inside of a body cavity or for observing the inside of a machine such as an engine, which is provided with a pupil dividing means and a secondary optical system for observing or picking up two divided images, respectively. It is used for various purposes. A stereoscopic endoscope of this type is disclosed in, for example, Japanese Patent Laid-Open No. 6-194.
No. 581 is disclosed.

In a conventional stereoscopic endoscope, a reflecting optical element such as a roof mirror and a reflecting prism is used as a pupil dividing means, and the divided luminous fluxes are separated from each other in a direction perpendicular to the optical axis of the primary optical system. Reflected in. The secondary optical system is provided with a pair of reflecting surfaces for reflecting the light flux reflected by the pupil splitting means again and directing it in the same direction.

[0004]

However, in the conventional stereoscopic endoscope, the pupil is divided by using the reflecting surface, and as described above, each separated light beam is directed to the optical axis of the primary optical system. On the other hand, since the light beams travel vertically and away from each other, there is a problem that the arrangement space of the secondary optical system that receives the separated light beams becomes large.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is a stereoscopic view in which the space between the optical paths after division can be reduced to reduce the space for arranging the secondary optical system. The purpose is to provide an endoscope.

[0006]

In order to achieve the above object, a stereoscopic endoscope according to the present invention includes a primary optical system having an objective lens system and a relay lens system arranged in order from the object side, A pupil division prism which is arranged at a pupil position of a primary optical system, divides a light flux in the pupil into two regions so that an object can be observed from different directions, and refracts the divided light flux in different directions. It has a pair of secondary optical system which takes in the light flux divided by.

[0007]

Embodiments of the stereoscopic endoscope according to the present invention will be described below.

[0008]

First Embodiment As shown in FIG. 1, a stereoscopic endoscope according to a first embodiment includes a tubular insertion portion 1 to be inserted into a narrow space such as a body cavity and a proximal end side of the insertion portion 1. And an observation unit 2 connected to the.

Inside the insertion section 1, an objective lens system 11 for forming an image of an object, which is composed of four elements in three groups, and an objective lens system 11 are provided.
The first relay lens system 12 including a plurality of lens systems for transmitting the image formed by and the second relay lens system 13 forming the exit pupil are sequentially arranged from the object side, and these lens systems are arranged. The primary optical system 10 is configured by the above.

In the observing section 2, the luminous flux in the pupil is divided into two regions so that the object can be observed from different directions, and
A pair of wedge-shaped pupil division prisms 70 and 71 for refracting the divided luminous fluxes in different directions are arranged so as to match the pupil position of the primary optical system 10, and these pupil division prisms 7 are arranged.
A pair of secondary optical systems 30a and 30b for receiving the light beams divided by 0 and 71 are arranged.

The pupil division prism 70 is constructed as an achromatic prism in which two prisms 70a and 70b having different dispersion values are bonded together in order to reduce chromatic aberration. Similarly, the other pupil division prism 71 also has two prisms 7.
It is configured as an achromatic prism by laminating 1a and 71b.

Conditions for achromatization are as follows: the apex angle of each prism is A1, A2, the dispersion value is V1, V2, and the refractive index is N.
It is given by the following equation, where Dt is the composite deviation angle of 1, N2 and both prisms.

[0013]

[Equation 1] A1 = Dt.V1 / ((N1-1). (V1-V2)) A2 = Dt.V2 / ((N2-1). (V2-V1))

The pupil splitting prisms 70 and 71 split the light flux reaching the pupil of the primary optical system 10 into two left and right components so that stereoscopic viewing is possible, and the respective components are split into the primary optical system 1 and the primary optical system 1.
The wedges are arranged symmetrically with respect to the optical axis Ax1 with the tip end side of the wedge directed toward the optical axis Ax1 of the primary optical system 10 so as to refract in a direction away from the optical axis Ax1.

Each of the secondary optical systems 30a and 30b comprises image forming lens systems 32a and 32b and image receiving elements 34a and 34b. The light beams split into the two regions by the pupil splitting prisms 70 and 71 are respectively formed into the imaging lens systems 32a and 3a.
2b is transmitted and an image is formed on the image pickup devices 34a and 34b such as CCD. The imaging lens systems 32a and 32b are arranged so as to be inclined with respect to the optical axis Ax1 of the primary optical system 10 so that their optical axes are parallel to the optical paths refracted by the pupil division prisms 70 and 71. And image pickup devices 34a and 34b
Are arranged so that their light receiving surfaces are perpendicular to the optical axes of the imaging lens systems 32a and 32b.

In order to enable stereoscopic vision, it is necessary to observe one object from different directions. For that purpose,
It is necessary to guide light beams that have passed through different regions in the pupil to the left and right secondary optical systems. Therefore, the pupil division prism 70,
Reference numeral 71 is provided at the pupil position of the primary optical system 10 symmetrically with respect to the optical axis. Thereby, the secondary optical systems 30a, 30
The central axis of the light beam incident on b has a predetermined interval on the pupil, and parallax corresponding to this interval can be given between the images captured by the respective imaging elements. The central axis of the light beam incident on the secondary optical system is defined as the axis passing through the center of gravity of the cross section of the divided light beam.

Therefore, a stereoscopic image can be obtained by displaying the images taken by the image pickup devices 34a and 34b on separate displays and observing the displays separately with the right eye and the left eye. Further, the image picked up by the image pickup means can be recorded by the VTR or the like while maintaining the stereoscopic information.

When the prism is used to deflect the optical path as described above, trapezoidal distortion occurs in the image formed on the image pickup device. In this embodiment, the image captured by the image sensor is subjected to image processing such as affine transformation to correct the trapezoidal distortion.

According to the first embodiment, by using the prism as the pupil splitting element, the angle formed by the split light beams can be set to the necessary minimum, and the space for disposing the secondary optical system can be made smaller than before. be able to. In particular, when an image is captured using the image sensor as in the first embodiment, it is not necessary to match the axial interval of the secondary optical system with the pupil distance, unlike the case of direct observation with the naked eye, and thus the imaging lens The size of the observation unit 2 can be minimized in accordance with the size of the image pickup device. Further, since the optical axes of the secondary optical system do not have to be parallel, the configuration of the secondary optical system can be simplified to only the imaging lens and the image pickup element.

[0020]

Second Embodiment FIG. 2 is an overall explanatory view showing a stereoscopic endoscope according to a second embodiment. In the second embodiment, the pupil division prisms 70, 71 are spaced apart from each other in the center, and the rectangular light shielding plate 22 is arranged so as to cover the space. Other configurations are the same as those of the first embodiment. By disposing the light shielding plate 22, the central portion of the pupil is shielded from light and the secondary optical systems 30a, 30
The distance between the central axes of the light beams incident on b (the distance between the incident axes) is set to be larger than that in the first embodiment in which the light shielding plate 22 is not provided.

When the distance between the central axes of the light beams entering the secondary optical system increases, the amount of light entering the secondary optical system decreases, but if the distance from the objective lens system to the observed object is the same, then the object Since the prospective angle becomes large, the three-dimensional effect (uplifting degree) can be increased. Therefore, a stereoscopic effect can be obtained even when the object distance is farther.

Even when the pupil division prisms 70 and 71 are arranged in contact with each other as shown in FIG. 3, the relay lens system 13 side is arranged so as to cover the tips of the wedges of both prisms. By providing the light-shielding plate 22 in the second embodiment, it is possible to obtain the effect of widening the interval between the incident axes as in the second embodiment. Further, in the case of the example in FIG. 3, if the width of the light shielding plate 22 can be changed, the stereoscopic effect can be changed during observation.

Also in the case of the second embodiment, since trapezoidal distortion occurs in the image on the image pickup element, image processing such as affine transformation is necessary when displaying this.

[0024]

Third Embodiment FIG. 4 is an overall explanatory view showing a third embodiment of the stereoscopic endoscope according to the present invention. In this embodiment, the secondary optical systems 30a and 30b are configured to allow visual observation. Since the configuration of the insertion section 1 is the same as that of the above-described embodiment, only the configuration of the observation section 2 will be described.

In the observation section 2, a pair of pupil division prisms 70 and 71 as pupil division means are arranged, and a pair of secondary optics for receiving the light beams divided by these pupil division prisms 70 and 71. Systems 30a, 30b are arranged. Each of the secondary optical systems 30a and 30b includes optical path deflecting prisms 72a and 72b, image forming lens systems 32a and 32b, and eyepiece lens systems 33a and 33b.

The light beams refracted by the pupil division prisms 70, 71 and refracted in the direction away from the optical axis Ax1 are refracted by the optical path deflecting prisms 72a, 72b in the direction parallel to the optical axis Ax1 of the primary optical system 10 and are combined. Image lens system 32
The light enters each of the left and right eyes of the observer via a, 32b and the eyepiece lens systems 33a, 33b, and the observer can stereoscopically observe the object.

The pupil division prisms 70 and 71 and the optical path deflecting prisms 72a and 72b are made of the same material and have the same apex angle, and the chromatic aberration generated on one side can be canceled by the other, so that each prism can be offset. It is not necessary to attach them alone to correct chromatic aberration.

When the prisms are used in combination as described above, trapezoidal distortion does not occur and the optical axes of the secondary optical system can be made parallel to each other, so that direct observation can be performed with the naked eye.

Also in the configuration of the third embodiment, the image pickup device is provided at the image plane position of the image forming lens systems 32a and 32b instead of the eyepiece lens systems 33a and 33b.
Similarly to, a stereoscopic image can be taken out as a video signal. In this case, image processing such as affine transformation for correcting trapezoidal distortion is unnecessary.

[0030]

[Embodiment 4] FIG. 5 is an optical path diagram of essential parts showing Embodiment 4 of a stereoscopic endoscope according to the present invention. Pupil division prism 7
Reference numeral 3 denotes a roof prism in which the thickness in the optical axis direction becomes thinner toward both ends with the optical axis Ax1 of the primary optical system as the center. The light fluxes incident on the incident end faces 73a and 73b are deflected toward the opposite side to the incident side with the optical axis as a boundary,
It is incident on the secondary optical systems 30a and 30b located on the opposite sides of the respective surfaces with the optical axis Ax1 interposed therebetween.

The light beams incident on the secondary optical systems 30a and 30b are imaged on the image pickup devices 34a and 34b by the image forming lenses 32a and 32b, respectively. In the fourth embodiment, the image on the image sensor includes trapezoidal distortion, and therefore image processing such as affine transformation is necessary to correct this.

FIG. 6 shows a modification of the fourth embodiment. In this example, the roof prism 73 and the imaging lenses 32a and 32b
A single optical path deflecting prism 74 is disposed between and. The light flux incident on one entrance end surface 73a of the pupil division prism 23 is emitted from the exit end surface 74a of the optical path deflecting prism 74 and enters the imaging lens 32a, and the light flux incident on the other entrance end surface 73b is emitted from the other. The light is emitted from the end face 74b and enters the imaging lens 32b.

Also in this example, since the apex angle of the pupil division prism 73 and the apex angle of the optical path deflecting prism 74 are set to be equal and each prism is made of the same material, the optical axis of the secondary optical system is set. Can be made parallel and the occurrence of chromatic aberration and trapezoidal distortion can be prevented.

[0034]

Fifth Embodiment FIG. 7 is an explanatory view of an observation section showing a fifth embodiment of the stereoscopic endoscope according to the present invention. The endoscope with a stereoscopic configuration according to the fifth embodiment includes an insertion portion 1 provided with a primary optical system 10.
A rigid endoscope for monocular vision is constructed only by this, and an observing section 2 provided with a pupil dividing means and a secondary optical system is attached to this rigid endoscope as a binocular vision adapter. The optical configuration is the same as that of the first embodiment shown in FIG.

A collar-shaped hood 14 is attached to the proximal end side of the insertion portion 1 to come into contact with the periphery of the observer's eyes when observing with a single eye to block ambient light. The observation part 2 is fixed to the insertion part 1 via an attachment 50 attached to the hood 14.

The attachment 50 includes a mounting ring 51 which is attached to the hood 14 from the observation section 2 side and surrounds the hood 14 from the outside, and a mounting piece 52 which is in contact with the hood 14 from the object side and is attached to the mounting ring 51. , A fixing bolt 5 for fixing the contact piece 52 to the mounting ring 51
And 3.

The mounting ring 51 has a disc portion 51a which is in contact with the hood 14 and has an opening formed in the center, and the disc portion 5a.
A cylindrical portion 51b that rises from the peripheral portion of 1a toward the object side and surrounds the outer periphery of the hood 14, and a flange portion 51c that is formed from the object-side tip of this cylindrical portion toward the inner periphery are integrally configured. ing. The contact piece 52 is a small piece having an L-shaped cross section, and is located at least at three circumferential positions.
4 is attached to the mounting ring 51.

On the outer peripheral portion of the surface of the mounting ring 51 on the observation portion 2 side, adjustment bolts 54 projecting toward the observation portion 2 side are fixed at three locations in the circumferential direction. In the observation section 2,
An outer flange 2b is formed in the peripheral portion on the insertion portion 1 side, and a through hole 2c into which the adjustment bolt 54 is inserted is formed in the outer flange 2b. Adjustment bolt 54
The nuts 55 and 56 located on both sides of the outer flange 2b while being inserted into the through hole 2c.
The insertion part 1 fixed to b and fixed to the attachment 50 is fixed to the observation part 2.

In the fifth embodiment, the three adjusting bolts 5
By adjusting the positions of the nuts 55 and 56 that are screwed into the screw 4, the positional relationship between the attachment 50 and the observation unit 2 can be three-dimensionally adjusted.

[0040]

As described above, according to the present invention, by utilizing the refraction effect of the prism for dividing the pupil, the spread angle of the divided light flux is made smaller than that using the reflection effect. Therefore, the space for disposing the secondary optical system can be reduced.

[Brief description of drawings]

FIG. 1 is an overall plan view showing a first embodiment of a stereoscopic endoscope of the present invention.

FIG. 2 is a plan view of an observation section showing a second embodiment of the stereoscopic endoscope of the present invention.

FIG. 3 is an optical path diagram of a main part showing a modified example of the second embodiment.

FIG. 4 is an overall plan view showing a third embodiment of the stereoscopic endoscope of the present invention.

FIG. 5 is an optical path diagram of a main part showing a fourth embodiment of the stereoscopic endoscope according to the present invention.

FIG. 6 is an optical path diagram of a main part showing a modified example of the fourth embodiment.

FIG. 7 is a plan view of an observation section showing a fifth embodiment of the stereoscopic endoscope according to the present invention.

[Explanation of symbols]

 1 Insertion Part 2 Observation Part 10 Primary Optical System 11 Objective Lens System 12 First Relay Lens System 13 Second Relay Lens System 14 Hood 30a, 30b Secondary Optical System 32a, 32b Imaging Lens System 34a, 34b Imaging Device 70 , 71 pupil division prism

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[Procedure amendment]

[Submission date] February 8, 1996

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 5

[Correction method] Change

[Correction content]

Claims (10)

[Claims] 1. A primary optical system having an objective lens system and a relay lens system sequentially arranged from the object side, and a primary optical system arranged at a pupil position of the primary optical system so that the object can be observed from different directions. Is divided into two regions, and the split light beam is refracted in different directions, and a pair of secondary optical systems for taking in the light beam split by the pupil division prism are provided. And stereoscopic endoscope. 2. The stereoscopic endoscope according to claim 1, wherein each of the pupil division prisms is an achromatic prism that reduces chromatic aberration due to the prism. 3. The stereoscopic vision according to claim 1, wherein the pupil division prism is composed of a pair of wedge-shaped prisms symmetrically arranged about an optical axis of the primary optical system. mirror. 4. The wedge-shaped prism is arranged such that a tip of the wedge is directed toward the optical axis so as to refract the divided light beam in a direction away from the optical axis of the primary optical system. The stereoscopic endoscope according to claim 3. 5. The pupil-splitting prism is a roof-type prism which is centered on the optical axis of the primary optical system and is distant from the center, and thus the thickness in the optical axis direction is reduced. The stereoscopic endoscope described. 6. The optical system according to claim 1, wherein the secondary optical system includes an optical path deflecting prism that refracts the light beam refracted by the pupil division prism in a direction parallel to the optical axis of the primary optical system. The stereoscopic endoscope described. 7. The stereoscopic endoscope according to claim 6, wherein the optical path deflecting prism has the same vertex angle and the same material as those of the pupil division prism. 8. The stereoscopic endoscope according to claim 6, wherein one optical path deflecting prism is arranged in each secondary optical system. 9. The secondary optical system comprises an imaging lens system for forming an image of each of the light beams split by the split prism, and an image pickup device for shooting the image. The stereoscopic endoscope according to. 10. The secondary optical system includes an imaging lens system for forming an image of each of the light beams split by the split prism, and an eyepiece lens system for guiding the image to an eye of an observer. The stereoscopic endoscope according to claim 1.