WO2017199666A1

WO2017199666A1 - Imaging device

Info

Publication number: WO2017199666A1
Application number: PCT/JP2017/015570
Authority: WO
Inventors: 菅武志; 富岡誠
Original assignee: オリンパス株式会社
Priority date: 2016-05-16
Filing date: 2017-04-18
Publication date: 2017-11-23

Abstract

The purpose of the present invention is to provide a compact imaging device that allows favorable 3D observations to be carried out. This imaging device 10 includes two optical systems LNS1, LNS2 arranged in parallel and generating two optical images with parallax therebetween, and an imaging element IMG for capturing the optical images generated by the two optical systems LNS1, LNS2. The imaging device 10 is characterized in that: the imaging device 10 includes movable lenses L31, L32 disposed in the two optical systems LNS1, LNS2 respectively and capable of changing the focal position by being moved along the optical axes AX1, AX2, one holding frame LB2 for holding the two movable lenses L31, L32, and one drive unit 100 for moving the holding frame LB2 along the optical axes AX1, AX2; the holding frame LB2 has a non-circular outer shape when viewed along the optical axes AX1, AX2; and the non-circular shape is formed so that the length along the parallax direction (figure 3, y direction) in the two optical systems LNS1, LNS2 is longer than the length dx along a direction perpendicular to the parallax direction (figure 3, x direction).

Description

Imaging device

The present invention relates to an imaging apparatus.

Conventionally, a stereoscopic observation system is known. The stereoscopic observation system uses a method of imaging two images with different parallaxes for stereoscopic viewing by forming images on substantially the same plane, for example, on the imaging surface of one imaging element. And in the structure of a prior art, in order to obtain two images with different parallax, it has two different optical systems.

Such a stereoscopic observation system uses an optical system for the left eye and the right eye. An image with parallax is captured by the left-eye optical system and the right-eye optical system. When a human recognizes an image with parallax in his / her head, a sense of distance is obtained and the image is observed three-dimensionally. A stereoscopic observation system, particularly a stereoscopic observation system for an endoscope, is proposed in Patent Documents 1, 2, and 3.

JP 2005-058374 A Japanese Patent Application Laid-Open No. 09-127435 JP 2002-85330 A

In the stereoscopic observation system, it is desirable to make the focal length variable by moving some of the lenses constituting the optical system along the optical axis. For this reason, a fitting clearance is provided between the holding frame of the moving lens and the holding frame of another fixed lens.

ガ Due to the fitting clearance, play may occur in the holding frame of the moving lens. When looseness occurs, a magnification shift, a vertical shift, and a horizontal shift occur between the left-eye image and the right-eye image, making it difficult to perform good stereoscopic observation.

In the configurations of Patent Documents 1 and 2, it is difficult to effectively reduce the deviation between the left eye image and the right eye image due to such play. In Patent Document 3, a difference in magnification between the left eye image and the right eye image is detected and corrected. With this configuration, there is a problem that the apparatus becomes large.

The present invention has been made in view of the above, and an object of the present invention is to provide an imaging apparatus that is small and can perform good stereoscopic observation.

In order to solve the above-described problems and achieve the object, an imaging apparatus according to at least some embodiments of the present invention includes two optical systems in parallel that generate two optical images having parallax with each other, two optical systems An image pickup device that picks up an optical image by an optical system, and is disposed in each of the two optical systems and moves in the optical axis direction to change a focal position, and two A holding frame for holding the movable lens and a driving unit for moving the holding frame in the optical axis direction, and the outer shape when the holding frame is viewed from the optical axis direction is The circular shape and the non-circular shape are characterized in that the length of the parallax direction of the two optical systems is longer than the length of the direction orthogonal to the parallax direction.

The present invention is advantageous in that it can provide an imaging device that is small and can perform good stereoscopic observation.

1 is a diagram illustrating a schematic configuration of an imaging apparatus according to a first embodiment. It is a figure which shows schematic structure of the imaging device which concerns on 2nd Embodiment. 2 is a perspective view illustrating a schematic configuration of a holding frame and a drive unit of the imaging apparatus according to the embodiment. 1 is a schematic configuration of a holding frame and a drive unit of an imaging apparatus according to an embodiment as viewed from an optical axis direction. It is a figure which shows the vertical shift of the left-right image in an image pick-up element surface. It is a figure which shows the rotation by the play of a holding frame. 1 is a diagram illustrating a schematic configuration of an imaging apparatus according to Embodiment 1. FIG. 1 is a diagram illustrating a lens cross-sectional configuration of an imaging apparatus according to Example 1. FIG. FIG. 3 is a diagram illustrating a schematic configuration of an imaging apparatus according to a second embodiment. 6 is a diagram illustrating a lens cross-sectional configuration of an imaging apparatus according to Example 2. FIG.

Hereinafter, an imaging apparatus according to an embodiment will be described in detail based on the drawings. In addition, this invention is not limited by this embodiment.

(First embodiment)
FIG. 1A is a diagram illustrating a schematic configuration of the imaging apparatus 10 according to the first embodiment. In the present embodiment, the imaging apparatus 10 includes two parallel optical systems LNS1 and LNS2 that generate two optical images having parallax with each other, and an imaging element IMG that captures an optical image by the two optical systems LNS1 and LNS2. The movable lenses L31 and L32 that are arranged in the two optical systems LNS1 and LNS2, respectively, move in the optical axis AX1 and AX2 directions and change the focal position, and the two movable lenses L31 and L32. Each holding frame LB2 and one drive unit 100 for moving the holding frame LB2 in the direction of the optical axes AX1 and AX2. The holding frame LB2 is viewed from the directions of the optical axes AX1 and AX2. The outer shape is a non-circular shape, and the non-circular shape is a direction in which the length dy in the parallax direction (y direction in FIG. 3) of the two optical systems LNS1 and LNS2 is orthogonal to the parallax direction ( 3, wherein the x-direction) of a long shape than the length dx.

The holding frame LB1 holds the lenses L1 and L2. The holding frame LB2 holds the lenses L31 and L32. The holding frame LB3 holds the aperture stop S, the lens L4, the parallel plate F1, and the lenses L5 and L6. The parallel flat plate F2, the parallel flat plate (cover glass) CG, and the image sensor IMG are joined. The holding frame LB4 holds the joined parallel plate F2, the parallel plate CG, and the imaging element IMG. The holding frames LB1, LB3, and LB4 are fixed. The holding frame LB2 has a fitting clearance so as to be movable in the arrow A direction with respect to the holding frame LB1.

In addition, in FIG. 1, the position which arrange | positions the drive part 100 is shown typically. The position where the driving unit 100 is disposed will be described later with reference to FIGS.

For example, the optical system LNS1 forms an image for the right eye, and the optical system LNS2 forms an image for the left eye. Thereby, the optical image by the two optical systems LNS1 and LNS2 can be captured by the imaging element IMG.

The optical system LNS1 has a movable lens L31 for moving in the direction of the optical axis AX1 to change the focal position. The optical system LNS2 includes a movable lens L32 that moves in the direction of the optical axis AX2 to change the focal position. This optical system can switch the object distance in focus without greatly changing the focal length. This makes it possible to perform close-up observation while maintaining a wide angle of view without greatly changing the angle of view.

FIG. 2 is a perspective view showing a schematic configuration of the holding frame LB2 and the drive unit 100 of the imaging device 10. As shown in FIG. FIG. 3 shows a schematic configuration of the holding frame LB2 and the driving unit 100 of the imaging device 10 as viewed from the optical axes AX1 and AX2. One holding frame LB2 holds two movable lenses L31 and L32. In addition, one drive unit 100 moves the holding frame LB2 in the direction of the optical axes AX1 and AX2 via the drive frame LB5. As described above, the image pickup apparatus can be downsized by one drive unit 100. In addition, since the movable lenses L31 and L32 are driven by the single holding frame LB2, the positional variation in the optical axes AX1 and AX2 directions of the two movable lenses L31 and L32 can be reduced.

The magnification difference between the left and right images will be described. FIG. 5 is a diagram illustrating the rotation of the holding frame LB2 due to backlash.

Suppose that the holding frame LB2 rotates in the direction of arrow B in the yz plane in FIGS. 2 and 3 due to the fitting clearance. In this case, the movable lenses L31 and L32 are displaced in the positions of the optical axes AX1 and AX2. Therefore, in the two optical systems LNS1 and LNS2, a magnification shift between the left and right images occurs.

In this embodiment, the movable lenses L31 and L32 are held by one holding frame LB2. For this reason, it is possible to reduce the magnification shift between the left and right images.

Further, the holding frame LB2 is moved in the optical axis AX1, AX2 direction, that is, the arrow A direction by one driving unit 100. Since only one driving unit 100 is required, the apparatus can be reduced in size. The drive unit 100 can be configured by, for example, a voice coil motor.

Next, the vertical displacement of the left and right images will be described. Consider the case of rotating in the direction of arrow C in the xy plane in FIG. In this case, the movable lenses L31 and L32 are decentered in a direction perpendicular to the optical axis. Therefore, in the imaging element IMG, vertical deviation occurs between the right eye image and the left eye image.

FIG. 4 is a diagram showing the vertical shift of the left and right images in the image sensor IMG. The right eye image R ′ and the left eye image L ′ are shifted in the vertical direction with respect to the right eye image R and the left eye image L without vertical displacement.

In this embodiment, when the holding frame LB2 is viewed from the optical axis AX1 and AX2 directions, the outer shape is a non-circular shape, and the non-circular shape is the parallax direction of the two optical systems LNS1 and LNS2 (FIG. 3, y direction). ) Is longer than the length dx in the direction orthogonal to the parallax direction (FIG. 3, x direction). In the present embodiment, the non-circular shape of the holding frame LB2 is a rectangular shape. In addition, it is not restricted to this shape, An elliptical shape and a polygonal shape may be sufficient.

When the outer diameter of the holding frame LB2 is, for example, a circular shape, there are few mechanical restrictions, so that the holding frame easily rotates around the optical axis. In the present embodiment, the length dy> dx of the outer diameter of the holding frame LB2. For example, by receiving the surface of the length dy with an opposing member (not shown), rotation (in the direction of arrow C in FIGS. 2 and 3) that causes vertical displacement can be reduced. Moreover, the spatial area | region which arrange | positions the drive part 100 mentioned later is securable by making holding frame LB2 non-circular shape.

In addition, since the two movable lenses L31 and L32 are fixed to the holding frame LB2, even if there is a fitting clearance (backlash), the right and left images are not shifted in principle.

Further, according to a preferred aspect of the present embodiment, as shown in FIG. 2, there are at least two position sensors provided in the vicinity of the two movable lenses L31 and L32 and for detecting the position of the holding frame LB2. Based on the positional information in the optical axis AX1 and AX2 directions of the holding frame LB2 detected by the Hall elements H1 and H2 and the Hall elements H1 and H2, two optical images having parallax by the two optical systems LNS1 and LNS2 are obtained. And an image processing unit 102 for electrical correction.

2 and 3, a hall element H1 is provided in the vicinity of the lens L31 of the holding frame LB2. A permanent magnet MG1 is provided at a position facing the hall element H1. The permanent magnet MG1 is fixed similarly to the fixed holding frames LB1, LB3, LB4. Thereby, the movement amount of the Hall element H1 can be detected based on the Hall output from the Hall element H1.

Further, a Hall element H2 is provided in the vicinity of the lens L32 of the holding frame LB2. A permanent magnet MG2 is provided at a position facing the hall element H2. The permanent magnet MG2 is fixed similarly to the fixed holding frames LB1, LB3, and LB4. Thereby, the movement amount of the Hall element H2 can be detected based on the Hall output from the Hall element H2.

The position of the holding frame LB2 may fluctuate when the lenses L31 and L32 are driven due to the influence of the fitting clearance (backlash) between the holding frame LB1 and the holding frame LB2. In particular, in the rotation mode in which the magnification deviation occurs as described above, deviation occurs in the directions of the optical axes AX1 and AX2 of the two Hall elements H1 and H2.

The output signal from the image sensor IMG is input to the image processing unit 102 via the A / D conversion unit 101. The image processing unit 102 calculates such a shift amount based on the Hall output from the Hall element H1 and the Hall output from the Hall element H2. Then, the image processing unit 102 performs image processing for electrically correcting the magnification shift between the left and right images based on the calculated value. The display unit 103 displays the corrected image.

Further, according to a preferred aspect of the present embodiment, it is desirable that one driving unit 100 is disposed in a direction (x direction) orthogonal to the parallax direction (y direction) of the two optical systems LNS1 and LNS2. First, since the number of driving units 100 is one, the apparatus can be downsized. In addition, by disposing the driving unit 100 in a direction (x direction) orthogonal to the parallax direction, the space margin in the x direction of the holding frame LB2 can be effectively used, and thus the apparatus can be downsized. For example, when the drive unit is provided in the y direction of the parallax, the size of the imaging device in the y direction only becomes larger, so when the imaging device is arranged at the endoscope tip, the outer diameter of the endoscope tip is reduced. It becomes difficult. In addition, if the drive unit is arranged between the two optical systems in the y direction, the parallax becomes large, and it is difficult to perform good stereoscopic observation. As described above, in the present embodiment, the above-described problem can be solved by arranging the driving unit 100 in a direction (x direction) orthogonal to the parallax direction. In this embodiment, the x is arranged at the position of x = 0, but the x position of the driving unit may be changed within a range where the imaging size in the y direction does not change.

(Second Embodiment)
FIG. 1B is a diagram illustrating a schematic configuration of the imaging apparatus 20 according to the second embodiment. The same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

Unlike the first embodiment, in this embodiment, the optical system LNS1 includes a movable lens CL1 that moves in the direction of the optical axis AX1 to change the focal length. The lens CL1 is configured by joining a lens L5 and a lens L6. The optical system LNS2 has a movable lens CL2 that moves in the direction of the optical axis AX2 to change the focal length. Thereby, at the time of magnifying observation, since the focal distance can be set long (the angle of view is narrow) and the object point distance in focus can be set short, more magnified observation becomes possible.

Also in such a zoom optical system, by having the configuration described in the first embodiment, it is possible to achieve the same effect as the imaging device 10 according to the first embodiment.

Example 1
An imaging apparatus according to Example 1 will be described. FIG. 6A is a diagram illustrating a schematic configuration of the imaging apparatus according to the present embodiment. FIG. 6B is a diagram illustrating a lens cross-sectional configuration of the imaging apparatus according to the present embodiment.

This example includes two optical systems LNS1 and 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 facing the image side, a negative meniscus lens L2 having a convex surface facing the image side, and a positive meniscus lens L31 (with a convex surface facing the object side). L32), aperture stop S, biconvex positive lens L4, parallel flat plate F1, biconvex positive lens L5, negative meniscus lens L6 with a convex surface facing the image side, parallel flat plate F2, and parallel flat plate CG. And the image sensor IMG.

The negative lens L1 is composed of an integral member with respect to the optical system LNS1 and the optical system LNS2. The positive lens L5 and the negative meniscus lens L6 are cemented. The parallel plate F2, the parallel plate CG, and the image sensor IMG are joined.

The holding frame LB1 holds the negative lens L1 and the negative meniscus lens L2. The holding frame LB2 holds the positive meniscus lenses L31 and L32. The holding frame LB3 holds the aperture stop S, the positive lens L4, the parallel flat plate F1, the positive lens L5, and the negative meniscus lens L6. The holding frame LB4 holds the parallel flat plate F2, the parallel flat plate CG, and the image sensor IMG. The holding frames LB1, LB3, and LB4 are fixed. The holding frame LB2 has a fitting clearance so as to be movable with respect to the holding frame LB1.

The optical system LNS1 has a movable lens L31 that moves in the direction of the optical axis AX1 to change the focal position. The optical system LNS2 includes a movable lens L32 that moves in the direction of the optical axis AX2 to change the focal position. Thereby, it is possible to switch the object point distance to be in focus with little change in the angle of view.

(Example 2)
An imaging apparatus according to Example 2 will be described. FIG. 7A is a diagram illustrating a schematic configuration of the imaging apparatus according to the present embodiment. FIG. 7B is a diagram illustrating a lens cross-sectional configuration of the imaging apparatus according to the present embodiment.

This example includes two optical systems LNS1 and 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 facing the image side, a parallel flat plate F1, a positive meniscus lens L2 having a convex surface facing the image side, a biconvex positive lens L3, A negative meniscus lens L4 having a convex surface facing the image side, an aperture stop S, a plano-concave negative lens L5 having a concave surface facing the image side, a positive meniscus lens L6 having a convex surface facing the object side, and a biconvex positive lens L7, a biconvex positive lens L8, a negative meniscus lens L9 having a convex surface facing the image side, a parallel plate F2, two parallel plates CG, and an image sensor IMG.

The negative lens L1 is composed of an integral member with respect to the optical system LNS1 and the optical system LNS2. The positive lens L3 and the negative meniscus lens L4 are cemented. The negative lens L5 and the positive meniscus lens L6 are cemented to form a lens CL1 (CL2). The positive lens L8 and the negative meniscus lens L9 are cemented. Two parallel flat plates CG and the image sensor IMG are joined.

The holding frame LB1 holds the negative lens L1, the parallel plate F1, the positive meniscus lens L2, the positive lens L3, and the negative meniscus lens L4. The holding frame LB2 holds the negative lens L5 and the positive meniscus lens L6. The holding frame LB3 holds the positive lens L7, the positive lens L8, and the negative meniscus lens L9. The holding frame LB4 holds the parallel flat plate F2, the two parallel flat plates CG, and the image sensor IMG. The holding frames LB1, LB3, and LB4 are fixed. The holding frame LB2 has a fitting clearance so as to be movable with respect to the holding frame LB1.

Unlike Example 1, in this example, the optical system LNS1 has a movable lens CL1 that moves in the direction of the optical axis AX1 to change the focal length. The lens CL1 is configured by joining a lens L5 and a lens L6. The optical system LNS2 has a movable lens CL2 that moves in the direction of the optical axis AX2 to change the focal length. Thereby, a zoom optical system can be provided in which the angle of view is changed and the focal length is variable.

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 distance between the lens surfaces, nd is the refractive index of the d-line of each lens (Numerical Example 1), ne is the refractive index of the e-line of each lens (numerical value) Example 2), νd is the Abbe number of each lens. S is an aperture stop.

Numerical example 1
Unit mm

Surface data Surface number r d nd νd
1 ∞ 0.2500 1.88815 40.76
2 0.592 0.6331
3 -0.9641 0.4900 1.85504 23.78
4 -1.1345 Variable
5 2.11 0.3917 1.58482 40.75
6 12.2107 Variable
7 (S) ∞ 0.0610
8 22.4495 0.5905 1.57124 56.36
9 -1.9442 0.0500
10 ∞ 0.4000 1.49557 75.00
11 ∞ 0.0656
12 1.3335 0.7598 1.69979 55.53
13 -0.8346 0.2798 1.93429 18.90
14 -3.6567 0.2520
15 ∞ 0.5000 1.51825 64.14
16 ∞ 0.3500 1.50700 63.26
Imaging surface ∞

Various data Normal observation Enlarged observation Focal length 0.426 0.396
Fno 3.04 3.09
Object distance 9.3 1.6
d4 0.39 0.69
d6 0.36 0.06

Numerical example 2
Unit mm

Surface number r d ne νd
1 ∞ 0.38 1.88815 40.76
2 1.363 0.85
3 ∞ 0.31 1.51564 75.00
4 ∞ 1.45
5 -5.355 1.05 1.65222 33.79
6 -2.355 0.03
7 4.019 0.98 1.77621 49.60
8 -3.296 0.30 1.93429 18.90
9 -19.843 Variable 10 (S) ∞ 0.01
11 ∞ 0.28 1.48915 70.23
12 1.455 0.38 1.59667 35.31
13 1.912 Variable 14 3.915 1.52 1.48915 70.23
15 -3.915 0.04
16 13.704 1.54 1.48915 70.23
17 -2.584 0.42 1.93429 18.90
18 -6.244 0.52
19 ∞ 0.40 1.52498 59.89
20 ∞ 0.65
21 ∞ 0.80 1.51825 64.14
22 ∞ 0.80 1.50801 60.00
23 (imaging surface) ∞

Various data Normal observation Intermediate Enlarged observation Focal length 1.70 1.8 1.85
Fno 7.09 8.09 8.15
Object distance 18.0 4.0 2.0
d9 0.32 0.85 1.38
d13 1.64 1.11 0.58

As described above, the present invention is useful for an imaging apparatus that is small and can perform good stereoscopic observation. The present invention can be modified. For example, the image processing unit that electrically corrects the optical image may correct the vertical shift of the images by correcting the positions of the two images based on the values of the two position sensors. Further, the optical system is not limited to two independent optical systems as in the above-described embodiments. For example, L1 may have a concave shape instead of two concave shapes, and may be configured to be shared by two optical systems.

LNS1 optical system LNS2 optical system LB1, LB2, LB3, LB4 Holding frame L31, L32, CL1, CL2 Movable lens LB5 Drive frame IMG Imaging element I Image plane (imaging plane)
L1 to L9 Lens F1, F2, CG Parallel plate S Brightness stop H1, H2 Hall element MG1,

MG2 Permanent magnet

10, 20 Imaging device 100 Drive unit 101 A / D conversion unit 102 Image processing unit 103 Display unit

Claims

An imaging apparatus having two parallel optical systems that generate two optical images having parallax with each other, and an image sensor that captures an optical image by the two optical systems,
A movable lens that is disposed in each of the two optical systems and moves in the direction of the optical axis to change the focal position;
One holding frame for holding the two movable lenses;
One drive unit for moving the holding frame in the optical axis direction,
The outer shape when the holding frame is viewed from the optical axis direction is a non-circular shape,
The non-circular shape is an imaging device in which a length of the two optical systems in a parallax direction is longer than a length in a direction orthogonal to the parallax direction.
At least two position sensors provided in the vicinity of the two movable lenses for detecting the position of the holding frame;
An image processing unit that electrically corrects the two optical images having parallax with each other based on the position information in the optical axis direction of the holding frame detected by the position sensor. The imaging apparatus according to claim 1.
3. The imaging apparatus according to claim 1, wherein the one drive unit is arranged in a direction orthogonal to a parallax direction of the two optical systems.