JPWO2018225613A1 - Imaging optical system and endoscope - Google Patents

Abstract

An endoscope application for stereoscopic vision, an imaging optical system which achieves both of high pixel count and flare reduction, and a channel, and an flare reduced endoscope. The imaging optical system includes two imaging optical systems OBJ-R and OBJ-L arranged in parallel, and the configuration of the flare stop of the two imaging optical systems OBJ-R and OBJ-L is different. Do. The optical axes Ax1 of the two imaging optical systems have the two imaging optical systems OBJ-R and OBJ-L used for imaging for three-dimensional observation and the channel CH for inserting the treatment tool. The distance between Ax2 is 2 mm or less, and the angle between the line connecting the center of the line connecting the centers of the lenses on the most object side of the two imaging optical systems and the center of the channel is , ± 45 degrees.

Description

  The present invention relates to an imaging optical system and an endoscope.

  Conventionally, stereoscopic observation systems are known. The stereoscopic observation system uses a method of imaging by imaging two images different in parallax on the imaging plane of the imaging device on substantially the same plane for stereoscopic viewing. And in a prior art structure, in order to obtain two images from which parallax differs, it has two different optical systems (for example, refer patent document 1, 2).

Unexamined-Japanese-Patent No. 2014-046075 JP, 2006-288821, A

  In prior art arrangements, flare may occur in the area between the two imaging optics. Such flare is not preferable because it degrades the quality of the observation image.

  The present invention has been made in view of the above, and is an endoscope application for stereoscopic vision, which has an imaging optical system which achieves both increase in number of pixels and reduction of flare, and a channel, and the flare is reduced. It aims at providing an endoscope.

  In order to solve the problems described above and to achieve the object, the present invention is characterized by having two optical systems for imaging in parallel and having different configurations of flare diaphragms of the optical systems for two imaging. It is an imaging optical system.

  The present invention according to another aspect has two optical systems for imaging in parallel, and the diameter of the lens on the most image side of the optical system of one of the two optical systems for imaging is the other optical system. This imaging optical system is characterized in that it is larger than the diameter of the lens on the most image side of the system.

  Furthermore, the present invention according to still another aspect has two optical systems for imaging used for imaging for three-dimensional observation and a channel through which a treatment tool is inserted, and optical axes of the optical systems for two imaging The distance between the two is less than 2 mm, and the angle between the line connecting the center of the line connecting the centers of the lenses on the most object side of the two imaging optical systems and the center of the channel is ± It is an endoscope characterized by being within 45 degrees.

  The present invention is an endoscope application for stereoscopic vision, which can provide an imaging optical system which achieves both increase in number of pixels and reduction of flare, and provides an endoscope having a channel and reduced flare. The effect of being able to

It is a figure which shows the lens cross-section structure of the imaging optical system which concerns on 1st Embodiment. It is a figure which shows the lens cross-section structure of the imaging optical system which concerns on 2nd Embodiment. (A) is a figure which shows the lens cross-section structure of the imaging optical system which concerns on 3rd Embodiment. (B) is a figure which shows the front structure of the one part lens of the imaging optical system which concerns on 3rd Embodiment. (A) is a figure showing the tip composition seen from the tip side of the endoscope concerning a 4th embodiment. (B) is a figure which shows the whole endoscope apparatus. It is a figure which shows the lens cross-section structure of the optical system for imaging which concerns on each embodiment. It is a figure which shows the flare which generate | occur | produces in the conventional imaging optical system.

  Below, based on the drawing which concerns on embodiment, it demonstrates in detail. The present invention is not limited by this embodiment.

First Embodiment
FIG. 1 is a view showing the lens cross-sectional configuration of the imaging optical system 100 according to the first embodiment. The present embodiment is characterized in that it has two imaging optical systems OBJ-R and OBJ-L in parallel, and the configuration of the flare stop of the two imaging optical systems OBJ-R and OBJ-L is different. Do. For example, the optical system OBJ-R is an optical system for imaging for the right eye. The optical system OBJ-L is an optical system for imaging for the left eye.

  The present embodiment and all of the second and third embodiments described below are imaging optical systems used for endoscopic imaging for three-dimensional observation, and the lens L1 on the most object side has two concave portions It is one optical member which has L11 and L12.

  The optical system for three-dimensional observation is an optical system OBJ-R and an optical system OBJ-L that generate two optical images having parallax with each other. For example, the optical system OBJ-R forms an image for the right eye, and the optical system OBJ-L forms an image for the left eye. The distance between the two optical axes Ax1 and Ax2 is 2 mm or less.

  Further, according to a preferable mode of the present embodiment, first, the two imaging optical systems OBJ-R and OBJ-L have the flare stop FS having the same configuration. Further, the flare stop FS3 is disposed only on the image side of the lens L5 on the most image side of one optical system OBJ-L.

Here, the occurrence of flare in a conventional imaging optical system will be described. FIG. 6 is a view showing a flare generated in a conventional imaging optical system. In the optical system OBJ-R for the right eye and the optical system OBJ-L for the left eye, light beams RAY-R and RAY-L shown by solid lines from an object (not shown) are incident on the imaging surface I to form an image Form.
Here, for example, in the optical system OBJ-L for the left eye, the light ray RAYf indicated by a broken line is reflected by the side surface of the lens L5 to cause flare. In particular, when the image quality is enhanced by using many pixels by increasing the number of pixels of the imaging device, it is necessary to form an optical image on a wider range of the imaging device surface. The position on the image plane of -R becomes high. Along with this, the height of the light beam at the lens L5 is increased, so that the light is reflected on the side surface of the lens to be flared.

  On the other hand, in the present embodiment, as shown in FIG. 1, the flare stop FS3 is disposed only on the image side of the lens L5 on the most image side of one optical system OBJ-L. Thereby, it is possible to reduce the flare that is generated by reflection on the side surface of the lens L5. Therefore, the quality of the observation image can be improved.

Second Embodiment
FIG. 2 is a diagram showing the lens cross-sectional configuration of the imaging optical system according to the second embodiment. In the imaging optical system 200 according to the second embodiment, one optical system OBJ-R of the two optical systems OBJ-L and OBJ-R and the other optical system OBJ-L are the same in the optical system. The flare diaphragms FS1 and FS2 are provided at the respective positions. The aperture diameter (aperture diameter) φ1 of the flare stop FS1 of one optical system OBJ-L is preferably smaller than the aperture diameter φ2 of the flare stop FS2 of the other optical system OBJ-R.

The values of the opening diameter are shown below.
Opening diameter φ1 = 0.5 (mm) of flare stop FS1
Opening diameter φ2 of the flare stop FS2 = 0.7 (mm)

  With such a flare stop configuration, a light ray having a high image height, which is originally a flare, is blocked by the flare stop FS1 having a smaller aperture diameter φ1. This can reduce the occurrence of flare.

  In the present embodiment, the brightness of the image of the optical system having the smaller aperture diameter is reduced. For this reason, the brightness is different between the right-eye image and the left-eye image. Therefore, it is preferable to adjust the gain by increasing electrically for the darker image. That is, when both the aperture diameters φ1 and φ2 are reduced, it is necessary to increase the electrical gain for both images, which causes a problem that electrical noise increases. In the present embodiment, this problem is avoided.

Third Embodiment
FIG. 3A is a view showing the lens cross-sectional configuration of the imaging optical system 300 according to the third embodiment.

  The present embodiment includes two imaging optical systems OBJ-R and OBJ-L in parallel, and one of the two imaging optical systems OBJ-R and OBJ-L is an optical system OBJ-R. The diameter LL1 of the lens L5 closest to the image is characterized by being larger than the diameter LL2 of the lens L5 closest to the image of the other optical system OBJ-L.

  FIG. 3B is a front view showing a lens of a part of the imaging optical system according to the third embodiment. The lens L5 on the most image side of the two imaging optical systems OBJ-R and OBJ-L has a shape that is circularly symmetrical with respect to the optical axes Ax1 and Ax2, and linearly cuts an arc portion in the parallax direction y The diameter of the lens L5 on the most image side of the two imaging optical systems OBJ-R and OBJ-L has the linear portion D, and the distance LL from the optical axes Ax1 and Ax2 to the linear portion D is referred to.

  In the lens L5, the diameter LL1 is made larger than the diameter LL2. As a result, even if the height of the light beam in the lens L5 is increased due to the increase in the number of pixels, the reflection of the light beam on the side surface of the lens L5 can be reduced. As a result, flare can be reduced.

Fourth Embodiment
FIG. 4A is a view showing a tip configuration as viewed from the tip side of the endoscope 400 according to the fourth embodiment. The present embodiment includes two imaging optical systems OBJ-L and OBJ-R used for imaging for three-dimensional observation, a channel CH for inserting a treatment tool, and illumination optical systems IL1 and IL2, The distance between the optical axes Ax1 and Ax2 of the two imaging optical systems OBJ-L and OBJ-R is 2 mm or less, and the center of the lens on the most object side of the two imaging optical systems OBJ-R and OBJ-L The angle α between the straight line connecting the center C1 of the line connecting the two and the center C2 of the channel CH and the line is characterized by being within ± 45 degrees.
(Endoscope explanation)
FIG. 4B is a view showing a schematic configuration of the endoscope apparatus 10 having the imaging optical system according to the embodiment. The endoscope device 10 is configured of an endoscope 400 and an extracorporeal device 7. The endoscope 400 includes an insertion unit 3, an operation unit 2, a connection cord 5 and a connector 6. Further, the in vitro apparatus 7 includes a power supply device, a video processor (not shown) that processes a video signal from the endoscope 400, and a display unit 8 that monitors and displays the video signal from the video processor.
The insertion portion 3 is formed of a slender and flexible member which can be inserted into a patient's body cavity, and the distal end portion is a rigid distal end rigid portion 1. A user (not shown) can perform various operations with an angle knob or the like provided on the operation unit 2.
Also, a connection cord 5 is extended from the operation unit 2. The connection cord portion 5 is connected to the in vitro device 7 via the connector 6.
Further, the connection cord unit 5 communicates the power supply voltage signal from the power supply device or the video processor, the drive signal from the imaging device, etc. to the imaging system (not shown) incorporated in the distal end rigid portion 1 and Communicate the video signal to the video processor. The video processor in the external device 7 can be connected to peripheral devices such as a video printer and a recording device (not shown). The video processor can perform predetermined signal processing on the video signal from the imaging system to display an endoscopic image on the display screen (monitor) of the display unit 8.
Moreover, the endoscope 400 of the present embodiment is not limited to the configuration in which the insertion portion 3 has flexibility. For example, a rigid endoscope in which the insertion portion 3 is not bent may be used.

  In the upper digestive tract endoscope, it is common to insert and remove the treatment instrument through the channel CH from a position obliquely below the screen side. This is in consideration of the operability of the treatment tool and the reduction in the diameter of the endoscope. Then, as shown in FIG. 4A and FIG. 6, when a bright spot exists in the parallax direction y, flare occurs only in the optical system closer to the bright spot.

  A bright spot is generated when the treatment tool is irradiated with illumination light from the illumination optical systems IL1 and IL2. That is, the treatment tool is made of metal such as silver, and has a very high light reflectance as compared to the tissue of the digestive tract. For this reason, when a treatment tool, for example, a forceps is inserted and removed from the channel CH, the reflected light from the forceps becomes a strong bright spot. Therefore, only in the left eye imaging close to the forceps, a horizontal streak-like flare occurs.

  Further, according to a preferable aspect of the present embodiment, of the two imaging optical systems OBJ-R and OBJ-L, the imaging optical system OBJ-L close to the channel CH has a flare preventing portion. Is preferred.

  Here, the flare preventing portion is the configuration for reducing the flare described in the first embodiment, the second embodiment, and the third embodiment.

  Thereby, in the endoscope which has the above-mentioned imaging optical system, it is effective in the ability to reduce the flare by the luminescent point in a treatment tool etc. In each of the above embodiments, the parallax is short, it corresponds to the increase in the number of pixels, and the flare and the like can be reduced. That is, when the parallax is shortened, it is necessary to reduce the diameter in the parallax direction of the lens L5 closest to the image (LL1 and LL2 in FIG. 3). However, when the lens diameter is reduced, as shown in FIG. 6, light is reflected on the side surface of the lens L5 and flare occurs. In the present embodiment, attention is paid to the fact that the bright spot (strong light) causing flare is generated due to the reflection of the treatment tool, and the channel for inserting and removing the treatment tool and the flare prevention unit are limited to only a specific optical system. By arranging, the above-mentioned effect is realized.

  Each embodiment will be described below. FIG. 5 is a view showing the lens cross-sectional configuration of the optical system for imaging according to each of the above embodiments.

(Numerical example of optical system for imaging)
The lens data of the two imaging optical systems OBJ-R and OBJ-L in the first to fourth embodiments are the same. Therefore, data of one of the two imaging optical systems OBJ-R and OBJ-L is shown below as a representative example.

  The imaging optical system includes, in order from the object side, a plano-concave first lens L1 having a negative refractive power with a concave surface facing the image side, and a meniscus-shaped first lens L1 having a negative refractive power with a concave surface facing the object side 2 lens L2, a third lens L3 having a plano-convex shape having a positive refracting power with a flat surface facing the image side, a filter F1 that is a parallel flat plate, a brightness stop S, a positive refraction with a flat surface facing the object side A fourth lens L4 having a plano-convex shape having a force, a fifth lens L5 having a positive refractive power and a cover glass having a positive refractive power in which a biconvex positive lens and a negative meniscus lens having a convex surface facing the image side are joined It has F2 and CCD cover glass CG.

  Further, the object side of the infrared absorption filter F1 is coated with a YAG laser cut coating, and the image side is coated with an LD laser cut coating. Further, the cover glass F2 and the CCD cover glass CG are joined. d16 is an adhesive layer.

  Below, numerical data of each of the above examples are shown. In the symbols, r is the radius of curvature of each lens surface, d is the distance between each lens surface, ne is the refractive index of e-line of each lens, ν d is the Abbe number of each lens, and F no is the F number. Also, the aperture is an aperture stop.

Numerical embodiment 1
Unit mm

Plane data Plane number rd ne dd
1 0.35 0.35 1.88815 40.76
2 0.592 0.564 1
3-1.522 0.46 1. 85504 23. 78
4-2.406 0.04 1
5 4.079 0.63 1.85504 23.78
6 0.03 0.03 1
7 0.4 0.4 1.49557 75.00
8 0.3 0.38 1
9 (aperture) ∞ 0.03 1
10 0.4 0.42 1.75453 35.33
11-1.717 0.437 1
12 1.381 0.82 1.69979 55.53
13-0.907 0.36 1.93429 18.90
14-4.334 0.38 1
15 0.5 0.5 1.51825 64.14
16 0.01 0.01 1.515 64.00
17 0.35 0.35 1.507 63.26
Image plane ∞

Various data focal length 0.43
Maximum image height 0.429
Angle of view 163.4
Fno 3.77
Object distance 7.25

Note that the above-described imaging optical system may simultaneously satisfy a plurality of configurations. This is preferable in order to obtain a good imaging optical system and an endoscope. Moreover, the combination of preferable structure is arbitrary.
As mentioned above, although various embodiments of the present invention were described, the present invention is not restricted only to these embodiments, and is an embodiment which constituted combining the composition of these embodiments suitably in the range which does not deviate from the meaning. The form is also within the scope of the present invention. For example, the optical system can be variously modified. The optical system may be a zoom optical system having a movable portion. Further, although the lens L1 is configured by one optical member in the present embodiment, two optical systems may be configured by different members. Further, the lens L1 to the lens L3 may be a common lens in the two optical systems. In that case, the distance between the optical axes of the lens L4 and the lens L5 may be 2 mm or less.

  As described above, the present invention is used for an endoscope for stereoscopic vision, and is useful for an imaging optical system that achieves both increased pixel count and reduced flare, and an endoscope having a channel and reduced flare. .

100, 200, 300 imaging optical system 400 endoscope L1-L5 lens Ax1, Ax2 optical axis S brightness aperture F1 filter F2 cover glass CG CCD cover glass L11, L12 concave part FS, FS1, FS2, FS3 flare aperture OBJ- Optical system for R, OBJ-L imaging
IL1, IL2 illumination optics CH channel φ1, φ2 aperture diameter LL1, LL2 diameter

In order to solve the problems described above and to achieve the object, the present invention has two optical systems for imaging in parallel , and a flare stop is provided only on the image side of the lens on the most image side of one optical system. It is an imaging optical system characterized by being disposed .

Claims (7)

Have two optical systems for imaging in parallel,
An imaging optical system characterized in that the configurations of flare diaphragms of the two imaging optical systems are different.   The imaging optical system according to claim 1, wherein a flare stop is disposed only on the image side of the lens closest to the image side of one of the optical systems. One of the optical system and the other have a flare stop at the same position in the optical system,
The imaging optical system according to claim 1, wherein the aperture diameter of the flare stop included in one of the optical systems is smaller than the aperture diameter of the flare stop included in the other optical system. Have two optical systems for imaging in parallel,
An imaging optical system, wherein a diameter of a lens on the most image side of one of the two imaging optical systems is larger than a diameter of a lens on the most image side of the other optical system. The lens on the most image side of the two imaging optical systems has a linear portion obtained by linearly cutting an arc portion in the parallax direction out of shapes circularly symmetrical with respect to the optical axis,
The imaging optical system according to claim 4, wherein a diameter of the lens on the most image side of the two imaging optical systems is a distance from an optical axis to the linear portion. Two imaging optical systems used for imaging for three-dimensional observation;
And a channel through which the treatment tool is passed;
The distance between the optical axes of the two imaging optical systems is 2 mm or less.
The angle between the line connecting the center of the line connecting the centers of the lenses on the most object side of the two imaging optical systems to the center of the channel and the line is within ± 45 degrees. An endoscope characterized by that. The endoscope according to claim 6, wherein the optical system for imaging close to the channel among the two optical systems for imaging has a flare preventing portion.

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