JP2013254125A - Stereoscopic imaging optical system and endoscope including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stereoscopic imaging optical system that has a compact and simple configuration and photographs right and left images with an arbitrary angle of convergence, and an endoscope including the stereoscopic imaging optical system.SOLUTION: An stereoscopic imaging optical system includes: a front lens group Gf having a single optical axis Lc; a back lens group Gb located on an opposite side relative to the front lens group, and having a single optical axis Lc arranged coaxially with that of the front lens group Gf; and a deflection unit 2 arranged at a position including an image forming surface Im forming an image once between the front lens group Gf and the back lens group Gb, and deflecting light beams.

Description

  The present invention relates to a stereoscopic imaging optical system capable of stereoscopic observation and an endoscope including the same.

  Conventionally, an optical system that forms two images with different parallax on a substantially identical plane for stereoscopic viewing has been disclosed (see Patent Documents 1 to 3).

  The technique described in Patent Document 1 performs pupil division by time division.

Japanese Patent No. 4750175

  However, in the technique described in Patent Document 1, two images with different parallax are formed on an imaging surface for stereoscopic viewing, and the left and right optical paths are captured in a time division manner for stereoscopic viewing. The two optical paths are selectively selected in a time-sharing manner to pick up left and right images. Therefore, a movable part for switching the left and right images at high speed is required, which increases the size.

  An object of the present invention is to provide a stereoscopic imaging optical system that captures left and right images at an arbitrary convergence angle and an endoscope including the same, while having a small and simple structure.

  A stereoscopic imaging optical system according to an embodiment of the present invention is a front lens group having a single optical axis, and is positioned on the opposite side of the object from the front lens group, and is disposed coaxially with the front lens group. And a rear lens group having a single optical axis, and a deflecting unit arranged at a position including an imaging surface that forms an image once between the front lens group and the rear lens group, and deflects the light beam. It is characterized by that.

  Further, an entrance pupil position is provided on the object side from the most object side surface of the front lens group.

Further, the distance in the optical axis direction between the center position of the deflecting unit in the optical axis direction and the imaging plane satisfies the following conditional expression (1).
d <| F | (1)
However,
d is the distance in the optical axis direction between the center position of the deflecting unit in the optical axis direction and the imaging plane;
F is the focal length of the entire system,
It is.

  The deflection unit includes two plate glasses, a bellows portion that connects the two plate glasses, and a liquid filled in a space surrounded by the two plate glasses and the bellows portion.

  The deflection unit includes two plate glasses, one of which has a flat surface and the other of which has an inclined surface. The two plate glasses are arranged so that the flat surface is orthogonal to the optical axis, and the optical axis is Each is arranged rotatably at the center.

  Furthermore, an endoscope according to an embodiment of the present invention includes the stereoscopic imaging optical system and an imaging element having an imaging surface disposed on the image side of the stereoscopic imaging optical system. .

  According to a stereoscopic imaging optical system and an endoscope including the same according to an embodiment of the present invention, it is possible to capture left and right images at an arbitrary convergence angle while having a small and simple structure.

It is sectional drawing of the stereo imaging optical system which concerns on one Embodiment of this invention. 3 is a cross-sectional view of the stereoscopic imaging optical system of Example 1. FIG. FIG. 3 is a diagram illustrating a deflecting unit used in Example 1. 2 is a diagram illustrating a left-right observation state of the stereoscopic imaging optical system of Example 1. FIG. FIG. 4 is an aberration diagram of the stereoscopic imaging optical system according to Example 1. FIG. 4 is an aberration diagram of the stereoscopic imaging optical system according to Example 1. 6 is a cross-sectional view of a stereoscopic imaging optical system of Example 2. FIG. 6 is a diagram illustrating a left-right observation state of the stereoscopic imaging optical system according to Example 2. FIG. 6 is an aberration diagram of the stereoscopic imaging optical system of Example 2. FIG. 6 is an aberration diagram of the stereoscopic imaging optical system of Example 2. FIG. 6 is a cross-sectional view of a stereoscopic imaging optical system of Example 3. FIG. FIG. 10 is a diagram illustrating a deflecting unit used in Example 3. It is a figure which shows the operating state of the deflection | deviation part used for Example 3. FIG. 6 is a diagram illustrating a left-right observation state of the stereoscopic imaging optical system of Example 3. FIG. FIG. 6 is an aberration diagram of the stereoscopic imaging optical system according to Example 3. FIG. 6 is an aberration diagram of the stereoscopic imaging optical system according to Example 3. It is a figure which shows an example of an endoscope. It is a figure which shows an example of a video endoscope. It is a figure which shows an example of a surgical microscope.

  A stereoscopic imaging optical system according to an embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view of a stereoscopic imaging optical system according to an embodiment of the present invention. The cross section is a YZ cross section of a coordinate system described later.

  A stereoscopic imaging optical system 1 according to an embodiment of the present invention includes a front lens group Gf having a single optical axis Lc, a position opposite to the object with respect to the front lens group Gf, and coaxial with the front lens group Gf. A deflection lens that is disposed at a position including a rear lens group Gb having a single optical axis Lc and an imaging plane Im that forms an image once between the front lens group Gf and the rear lens group Gb. Part 2.

  The light beam exiting the object enters the front lens group Gf having a single optical axis, forms a thick light beam, and forms an image once in the optical path between the front lens group Gf and the rear lens group Gb. The aerial image formed once is relayed with a relatively thin light beam by the rear lens group Gb having the stop S, and is imaged on the imaging surface.

  At this time, the deflecting unit 2 is arranged at a position including the imaging surface Im formed once, and the light beam is swung left and right by the deflecting unit 2 to fix the stop S in the rear lens group Gb. However, the entrance pupil E can be moved in the direction perpendicular to the optical axis Lc by the deflecting unit 2. Then, it is possible to perform stereoscopic imaging of an image of an arbitrary viewpoint by imaging in accordance with the moving position of the entrance pupil E.

The distance in the optical axis direction between the center position 2 ′ of the deflecting unit 2 in the optical axis Lc direction and the imaging plane Im satisfies the following conditional expression (1).
d <| F | (1)
However,
d is the distance in the optical axis Lc direction between the center position 2 ′ of the deflecting unit 2 in the optical axis Lc direction and the imaging plane Im;
F is the focal length of the entire system,
It is.

  If the conditional expression (1) is not satisfied, the movement of the image position by the deflecting unit 2 increases beyond the resolution limit, and the resolving power is significantly reduced.

  By disposing the deflecting unit 2 at a position including the imaging surface Im, the object plane and the deflecting unit 2 have a conjugate positional relationship, and even if the deflection angle is changed by the deflecting unit 2, the temporary image position does not move. Even if the image is picked up during the change, the image can be picked up without blurring and degrading the resolution and contrast. The distance in the optical axis direction between the center position 2 ′ of the deflecting unit 2 in the optical axis Lc direction and the imaging plane Im is more preferably 0.

  A diaphragm S is disposed in the rear lens group Gb. The stop S forms an entrance pupil E on the object side through the front lens group Gf.

  The vergence angle provides a three-dimensional effect with a natural viewing distance when a person works by hand. The convergence angle when working at a distance of 500 mm with an eye width of 60 mm is 3.43 deg. In the present embodiment, the object distance of 16 mm is achieved while realizing the convergence angle, and the outer shape of the optical system is successfully reduced.

  In general, as an optical system type that can capture a wide angle of view, a lens type in which a strong negative lens is arranged on the most object side is known. However, an entrance pupil should be arranged in the optical system and a convergence angle should be secured. Then, the entrance pupils of the left and right optical paths in the optical system are greatly separated from the optical axis, and as a result, the optical system has a large aperture.

  In order to solve this problem, it is important to place the entrance pupil E further on the object side than the most object side surface of the front lens group Gf. With this arrangement, it becomes possible to reduce the outer shape of the optical system while ensuring a convergence angle and an observation angle of view.

  Next, each example will be described.

  FIG. 2 is a sectional view of the stereoscopic imaging optical system according to the first embodiment. The cross section is a YZ cross section of a coordinate system described later.

  The stereoscopic imaging optical system 1 of Example 1 includes a front lens group Gf having a single optical axis Lc, a rear lens group Gb having a single optical axis Lc arranged coaxially with the front lens group Gf, and a front lens. And a deflecting unit 2 that deflects a light beam that is disposed at a position including an imaging surface Im that forms an image once between the group Gf and the rear lens group Gb. The stereoscopic imaging optical system 1 of Example 1 is particularly preferably used for an endoscope.

The front lens group Gf is formed by joining, in order from the object side to the image side, a planoconvex positive lens L _f1 having a plane facing the object side, a biconvex positive lens L _f2 and a positive meniscus lens L _f3 having a convex surface facing the image side. Lens SU _f1 .

The rear lens group Gb includes, in order from the object side to the image side, a biconvex positive lens L _b1 , a cemented lens SU _{b1 of} a biconcave negative lens L _b2 and a biconvex positive lens L _b3, a biconvex positive lens L _r4 , Have

A stop S is disposed on the object side of the cemented lens SU _b1 of the rear lens group Gb. The stop S forms an entrance pupil E on the object side through the front lens group Gf.

  The position of the entrance pupil E is arranged closer to the object side than the most object side surface of the front lens group Gf.

  FIG. 3 is a diagram illustrating a deflection unit used in the first embodiment.

  The deflecting unit 2 according to the first embodiment includes two plate glasses 2a and 2b, a bellows portion 2c connecting the two plate glasses 2a and 2b, and a space surrounded by the two plate glasses 2a and 2b and the bellows portion 2c. A liquid 3 to be filled.

  In this embodiment, the liquid 3 uses water, but a liquid with high refraction and low dispersion is preferred.

  The deflecting unit 2 according to the first embodiment can change the thickness in the optical axis direction by operating the bellows unit 2c. The deflecting unit 2 is disposed at a position including the imaging plane Im shown in FIG. 2, and the diaphragm S of the rear lens group Gb is fixed by changing the thickness in the optical axis direction and swinging the light beam left and right. In this state, the entrance pupil E can be moved in a direction orthogonal to the optical axis Lc. Then, it is possible to capture an image of an arbitrary viewpoint by capturing an image in synchronization with the movement of the entrance pupil E.

  FIG. 4 is a diagram illustrating a left-right observation state of the stereoscopic imaging optical system according to the first embodiment. 4A shows the left observation state, and FIG. 4B shows the right observation state. The cross section is an XZ cross section of a coordinate system described later.

  As shown in FIG. 4A, in the left observation state of the stereoscopic imaging optical system 1 of Example 1, the right side is folded and the left side is extended with respect to the optical axis of the bellows part 2c of the deflection unit 2 shown in FIG. Thus, the exit pupil E is moved to the left with respect to the optical axis Lc.

  Further, as shown in FIG. 4B, in the right observation state of the stereoscopic imaging optical system 1 of Example 1, the left side is folded with respect to the optical axis of the bellows part 2c of the deflection unit 2 shown in FIG. Is extended to move the exit pupil E to the right side with respect to the optical axis Lc.

  According to such a three-dimensional imaging optical system 1, it is possible to capture left and right images at an arbitrary convergence angle while having a small and simple structure.

  4 and 5 are aberration diagrams of the stereoscopic imaging optical system of Example 1. FIG. Since the left observation state and the right observation state are symmetrical, only the aberration diagram of the one-side optical path is shown.

  These aberration diagrams show 656.3 nm (C line: broken line), 587.6 nm (d line: solid line), and 486.1 nm (F) in the X direction and Y direction, respectively, at the angle of view shown in the parentheses at the center. Lines: dashed lines) for each wavelength. The same applies to the aberration diagrams.

  FIG. 7 is a sectional view of the stereoscopic imaging optical system according to the second embodiment. The cross section is a YZ cross section of a coordinate system described later.

  The stereoscopic imaging optical system 1 of Example 2 includes a front lens group Gf having a single optical axis Lc, a rear lens group Gb having a single optical axis Lc arranged coaxially with the front lens group Gf, and a front lens. And a deflecting unit 2 that deflects a light beam that is disposed at a position including an imaging surface Im that forms an image once between the group Gf and the rear lens group Gb. The stereoscopic imaging optical system 1 of Example 2 is particularly preferably used for a binocular stereomicroscope.

The front lens group Gf includes, in order from the object side to the image side, a planoconvex positive lens L _f1 having a plane facing the object side, and a cemented lens SU _f1 of a biconvex positive lens L _f2 and a biconcave negative lens L _f3. Have.

The rear lens group Gb includes, in order from the object side to the image side, a biconvex positive lens L _b1 , a cemented lens SU _{b1 of} a biconcave negative lens L _b2 and a biconvex positive lens L _b3, a biconvex positive lens L _r4 , Have

A stop S is disposed on the object side of the cemented lens SU _b1 of the rear lens group Gb. The stop S forms an entrance pupil E on the object side through the front lens group Gf.

  The position of the entrance pupil E is arranged closer to the object side than the most object side surface of the front lens group Gf.

  The deflecting unit 2 of the second embodiment has the same configuration as the deflecting unit 2 of the first embodiment shown in FIG.

  FIG. 8 is a diagram illustrating a left-right observation state of the stereoscopic imaging optical system according to the second embodiment. FIG. 8A shows the left observation state, and FIG. 8B shows the right observation state. The cross section is an XZ cross section of a coordinate system described later.

  As shown in FIG. 8A, in the left observation state of the stereoscopic imaging optical system 1 of Example 2, the right side is folded and the left side is extended with respect to the optical axis of the bellows part 2c of the deflecting unit 2 shown in FIG. Thus, the exit pupil E is moved to the left with respect to the optical axis Lc.

  Further, as shown in FIG. 8B, in the right observation state of the stereoscopic imaging optical system 1 of Example 2, the left side is folded with respect to the optical axis of the bellows part 2c of the deflecting unit 2 shown in FIG. Is extended to move the exit pupil E to the right side with respect to the optical axis Lc.

  According to such a three-dimensional imaging optical system 1, it is possible to capture left and right images at an arbitrary convergence angle while having a small and simple structure.

  9 and 10 are aberration diagrams of the stereoscopic imaging optical system of Example 2. FIG. Since the left observation state and the right observation state are symmetrical, only the aberration diagram of the one-side optical path is shown.

  FIG. 11 is a cross-sectional view of the stereoscopic imaging optical system according to the third embodiment. The cross section is a YZ cross section of a coordinate system described later.

  The stereoscopic imaging optical system 1 of Example 3 includes a front lens group Gf having a single optical axis Lc, a rear lens group Gb arranged coaxially with the front lens group Gf and having a single optical axis Lc, and a front lens. And a deflecting unit 2 that deflects a light beam that is disposed at a position including an imaging surface Im that forms an image once between the group Gf and the rear lens group Gb.

The front lens group Gf is formed by joining, in order from the object side to the image side, a planoconvex positive lens L _f1 having a plane facing the object side, a biconvex positive lens L _f2 and a positive meniscus lens L _f3 having a convex surface facing the image side. Lens SU _f1 .

The rear lens group Gb includes, in order from the object side to the image side, a positive meniscus lens L _b1 having a convex surface facing the image side, a cemented lens SU _{b1 of} a biconcave negative lens L _b2 and a biconvex positive lens L _b3 , and a biconvex lens It has a positive lens L _r4 and a cemented lens SU _b2 of a biconcave negative lens L _b5 .

An aperture stop S is disposed on the object side of the cemented lens SU _b1 on the object side of the rear lens group Gb. The stop S forms an entrance pupil E on the object side through the front lens group Gf.

  The position of the entrance pupil E is arranged closer to the object side than the most object side surface of the front lens group Gf.

  FIG. 12 is a diagram illustrating a deflecting unit used in the third embodiment. Fig.12 (a) is a figure which shows 1st plate glass, FIG.12 (b) is 2nd plate glass. FIG. 13 is a diagram illustrating an operating state of the deflection unit used in the third embodiment.

The deflecting unit 12 used in the third embodiment includes a first plate glass 12a shown in FIG. 12A having _one plane 12a ₁ and the other inclined plane 12a ₂ , one inclined plane 12b ₂ , and the other plane 12b _1. The second glass plate 12b shown in FIG. The star mark is a portion where the thickness in the optical axis direction of the first glass sheet 12a and the second glass sheet 12b is the thinnest.

As shown in FIG. 13, the deflection unit 12, the plane 12a ₁ of the first glass sheet 12a the plane 12a ₂ of the second glass sheet 12b are opposed, respectively disposed about the optical axis Lc so as to be perpendicular to the optical axis Lc To do. A space is provided between the first glass sheet 12a and the second glass sheet 12b. The space is formed for smooth operation, but may be omitted.

  Further, the first glass sheet 12a and the second glass sheet 12b are rotatable about the optical axis Lc. For example, the first glass sheet 12a and the second glass sheet 12b can be rotated in opposite directions. In Example 3, when viewed from the object side, the first glass sheet 12a can be rotated clockwise and the second glass sheet 12b can be rotated counterclockwise, but the first glass sheet 12a can be rotated counterclockwise. The second glass plate 12b may be rotatable in the clockwise direction. Further, the first glass sheet 12a and the second glass sheet 12b may be rotatable in the same direction.

  FIG. 13A is a diagram illustrating the deflection unit 12 in the left observation state. In the deflection unit 12 in the left observation state, the thinnest part of the first glass sheet 12a and the thinnest part of the second glass sheet 12b are arranged on the right side with respect to the optical axis Lc.

  FIG. 13B is a diagram illustrating the deflecting unit 12 in the middle of rotational movement from the left observation state to the right observation state. From the left observation state shown in FIG. 13 (a), as shown in FIG. 13 (b), the first glass sheet 12a is rotated clockwise as viewed from the object side, and the second glass sheet 12b is viewed from the object side. Rotate clockwise.

  FIG. 13C shows the deflecting unit 12 in the right observation state. In the deflection unit 12 in the right observation state, the thinnest portion of the first glass plate 12a and the thinnest portion of the second glass plate 12b are disposed on the left side with respect to the optical axis Lc.

  FIG. 13D is a diagram illustrating the deflecting unit 12 in the middle of rotational movement from the right observation state to the left observation state. From the right observation state shown in FIG. 13C, as shown in FIG. 13D, the first glass sheet 12a is rotated clockwise as viewed from the object side, and the second glass sheet 12b is viewed from the object side. Rotate clockwise.

  As described above, the deflecting unit 12 used in the third embodiment can change the thickness in the optical axis direction by rotating and moving the two plate glasses 12a and 12b. The deflecting unit 12 is disposed at a position including the imaging plane Im shown in FIG. 11, changes the thickness in the optical axis direction, and swings the light beam left and right to fix the stop S of the rear lens group Gb. In this state, the entrance pupil E can be moved in a direction orthogonal to the optical axis Lc. Then, it is possible to capture an image of an arbitrary viewpoint by capturing an image in synchronization with the movement of the entrance pupil E.

  FIG. 14 is a diagram illustrating a left-right observation state of the stereoscopic imaging optical system according to the third embodiment. 14A shows the left observation state, and FIG. 14B shows the right observation state. The cross section is an XZ cross section of a coordinate system described later.

  As shown in FIG. 14A, in the left observation state of the stereoscopic imaging optical system 1 according to the third embodiment, the thin portion of the deflection unit 12 shown in FIG. 13 is arranged on the right side with respect to the optical axis Lc, thereby emitting light. The pupil E is moved to the left with respect to the optical axis Lc.

  Further, as shown in FIG. 14B, in the right observation state of the stereoscopic imaging optical system 1 of Example 3, the thin portion of the deflection unit 12 shown in FIG. 13 is arranged on the right side with respect to the optical axis Lc. The exit pupil E is moved to the left with respect to the optical axis Lc.

  15 and 16 are aberration diagrams of the stereoscopic imaging optical system of Example 2. FIG. Since the left observation state and the right observation state are symmetrical, only the aberration diagram of the one-side optical path is shown.

The configuration parameters of Embodiments 1 to 3 are shown below. Eccentricity is given with the optical axis Lc as the Z-axis, and each surface is given in the X-axis direction corresponding to the left-right direction, and the inclination β is the direction of rotation around the Y-axis. After the eccentricity, it returns to the origin before the eccentricity and proceeds in the Z-axis direction given by the surface interval to be the origin of the next surface. The refractive index and the Abbe number are shown for the d-line (wavelength 587.56 nm). Since the lens data is symmetrical, only one side is shown. The unit of length is mm.

Example 1
specification

Object distance 16.00
NA 0.023
Focal length -2.35
Magnification -0.195
Angle of convergence (one side deg) 3.44
Image height 1.80 x 3.20 (vertical x horizontal)

Surface data Surface number Curvature radius Surface spacing Eccentric Refractive index Abbe number Object surface ∞ 16.00
1 ∞ 2.00 1.8830 40.7
2 -6.33 0.10
3 13.50 4.00 1.8830 40.7
4 -5.00 1.00 1.9229 18.9
5 -17.03 2.60
6 ∞ 0.10 Eccentricity (1) 1.5163 64.1
7 ∞ 2.00 Eccentricity (1) 1.3330 55.7
8 ∞ 0.10 Eccentricity (2) 1.5163 64.1
9 ∞ 1.00 Eccentricity (2)
10 95.26 2.00 1.8830 40.7
11 -8.31 5.97
12 Diaphragm surface 0.30
13 -4.11 1.00 1.9229 18.9
14 4.12 2.00 1.6031 60.6
15 -2.54 0.10
16 5.12 2.00 1.5688 56.3
17 -11.74 5.74
Image plane ∞

Eccentric [1]
X 0.00 Y 0.00 Z 0.00
α 0.00 β 14.78 γ 0.00

Eccentric [2]
X 0.00 Y 0.00 Z 0.00
α 0.00 β -14.78 γ 0.00

Example 2
specification

Object distance 16.00
NA 0.0645
Focal length -8.44
Magnification -2.00
Angle of convergence (one side deg) 3.44
Image height 1.80 x 3.20 (vertical x horizontal)

Surface data Surface number Curvature radius Surface spacing Eccentric Refractive index Abbe number Object surface ∞ 16.00
1 ∞ 2.00 1.8830 40.7
2 -13.19 0.10
3 6.79 3.00 1.8830 40.7
4 -5.00 1.00 1.9229 18.9
5 39.33 5.48
6 ∞ 0.10 Eccentricity (1) 1.5163 64.1
7 ∞ 1.00 Eccentricity (1) 1.3 330 55.7
8 ∞ 0.10 Eccentricity (2) 1.5163 64.1
9 ∞ 1.00 Eccentricity (2)
10 7.64 1.00 1.8830 40.7
11 -3.01 2.34
12 Diaphragm surface 0.30
13 -1.44 1.00 1.7552 27.5
14 1.23 1.50 1.7408 27.8
15 -2.43 0.10
16 17.37 1.50 1.5688 56.3
17 -9.98 18.18
Image plane ∞

Eccentric [1]
X 0.00 Y 0.00 Z 0.00
α 0.00 β 10.02 γ 0.00

Eccentric [2]
X 0.00 Y 0.00 Z 0.00
α 0.00 β -10.02 γ 0.00

Example 3
specification

Object distance 10.00
NA 0.066
Focal length -3.68
Magnification -1.00
Angle of convergence (one side deg) 3.44
Image height 1.80 x 3.20 (vertical x horizontal)

Surface data surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object surface ∞ 11.00
1 ∞ 1.00 1.8830 40.7
2 -13.19 0.10
2 -10.41 0.10
3 9.90 1.50 1.8830 40.7
4 -5.00 0.70 1.9229 18.9
5 -50.24 10.04
6 ∞ 0.50 Eccentricity (1) 1.8830 40.7
7 ∞ 0.10
8 ∞ 0.50 1.8830 40.7
9 ∞ 1.00 Eccentricity (2)
10 -5.58 1.00 1.8830 40.7
11 -3.05 10.66
12 Diaphragm surface 0.30
13 -15.82 0.50 1.7195 29.2
14 0.96 1.00 1.7173 47.1
15 -3.85 0.10
16 1.81 1.00 1.7253 29.8
17 -1.22 0.50 1.7416 45.0
18 1.20 4.99
Image plane ∞

Eccentric [1]
X 0.00 Y 0.00 Z 0.00
α 0.00 β 10.02 γ 0.00

Eccentric [2]
X 0.00 Y 0.00 Z 0.00
α 0.00 β -10.02 γ 0.00

  The values of conditional expression (1) for Examples 1 to 3 are shown below.

Example 1 Example 2 Example 3
d 1.00 0.20 0.55
| f | 2.35 8.44 3.68

  Furthermore, the stereoscopic imaging optical system 1 of the present embodiment can be used for an endoscope together with an imaging device having an imaging surface.

  FIG. 17 is a diagram illustrating an example of an endoscope.

  As shown in FIG. 17, the endoscope 101 is a side-view type endoscope. The endoscope 101 includes an elongated and flexible insertion portion 102, an operation portion 103 provided continuously with a proximal end portion of the insertion portion 102, and a universal cord 104 extending from a side portion of the operation portion 103. It is mainly composed in preparation. A connector that is connected to a light source device (not shown) that is an external device of the endoscope, a video processor, and the like is provided at the base end portion of the universal cord 104.

  The insertion portion 102 includes, in order from the distal end side, a distal end portion 105 formed of a hard member, a bending portion 106 configured to be able to bend in the vertical and horizontal directions, and a flexible flexible tube portion 107, for example. Configured. The distal end portion 105 has, on its side surface, an observation window 109 for capturing an optical image and an illumination range conversion unit 110 that illuminates the periphery of the observation window 109. The illumination range conversion unit 110 is an optical member that expands the illumination range of illumination light emitted from a light emitting unit 108 (described later) provided at the distal end of the observation window 109 to the distal end side and the proximal end side of the observation window 109.

  The operation unit 103 is provided with bending operation knobs 111 and 112 that change the bending direction of the bending unit 106. In addition, the operation unit 103 is provided with various switches 113 for remotely instructing light amount adjustment of the light source device, or stopping or photographing an endoscopic image displayed on a display device (not shown). Further, the operation unit 103 is provided with an air / water supply button 114 for controlling the air supply function and the water supply function, and a suction button 115 for controlling the suction function.

  As shown in FIG. 17, the tip portion 105 is formed in a cylindrical shape by integrally fixing a tubular tip portion main body 117 and a columnar tip portion constituting portion 118, and in the inner space of the tube portion in order from the tip side. An illumination optical system and an observation optical system (not shown) are arranged. The tip end body 117 and the tip constituent portion 118 are, for example, a metal member such as stainless steel or a resin member that does not transmit light.

  Note that the stereoscopic imaging optical system 1 of the present embodiment can also be used in a video endoscope as shown in FIG. 18, or a surgical microscope, a measuring instrument as shown in FIG.

  Although various embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and embodiments configured by appropriately combining the configurations of the respective embodiments also fall within the scope of the present invention. Is.

DESCRIPTION OF SYMBOLS 1 ... Stereo imaging optical system Gf ... Front lens group Gb ... Rear lens group 2, 12 ... Deflection part I ... Image surface

Claims (6)

A front lens group having a single optical axis;
A rear lens group having a single optical axis located on the opposite side of the object to the front lens group and arranged coaxially with the front lens group;
A deflecting unit that is disposed at a position including an imaging surface that forms an image once between the front lens group and the rear lens group;
A stereoscopic imaging optical system comprising: The stereoscopic imaging optical system according to claim 1, further comprising an entrance pupil position closer to an object side than a surface closest to the object side of the front lens group. The stereoscopic imaging optical system according to claim 1 or 2, wherein a distance in the optical axis direction between a center position of the deflecting unit in the optical axis direction and the imaging plane satisfies the following conditional expression (1). .
d <| F | (1)
However,
d is the distance in the optical axis direction between the center position of the deflecting unit in the optical axis direction and the imaging plane;
F is the focal length of the entire system,
It is. The deflection unit is
Two sheet glasses,
A bellows part connecting the two plate glasses;
A liquid filled in a space surrounded by the two plate glasses and the bellows part;
The three-dimensional imaging optical system according to claim 1, comprising: The deflection unit is
It has two plate glasses, one with a flat surface and the other with an inclined surface,
The stereoscopic imaging optical according to any one of claims 1 to 3, wherein the two plate glasses are arranged so that the plane is orthogonal to the optical axis and are respectively rotatable around the optical axis. system. The stereoscopic imaging optical system according to any one of claims 1 to 5,
An imaging device having an imaging surface disposed on the image side of the stereoscopic imaging optical system;
An endoscope characterized by comprising:

Images