JP2022112181A - Ocular imaging apparatus - Google Patents

Abstract

To reduce a risk of occurrence of bright points in a captured image.SOLUTION: An ocular imaging apparatus comprises: a light projecting optical system which projects light emitted from a light source, to the eyeground of a subject eye; an imaging optical system which images the subject eye illuminated with reflection light from the eyeground; and a shading part which is disposed at the light projecting optical system and shades a predetermined range including an optical axis, out of light having passed through the light projecting optical system. A conjugate point of the light source exists in front of the subject eye.SELECTED DRAWING: Figure 5

Description

The present invention relates to an eye imaging device.

2. Description of the Related Art There is a technique of projecting light onto an eye to be inspected and taking an image of the eye to be inspected when determining the presence or absence of an eye disease or diagnosing the postoperative course of the eye. In such a technique, when the subject's eye is photographed, light reflected from the subject's eye may cause a bright spot in the photographed image, and a situation may occur in which a desired portion cannot be photographed. Japanese Patent Application Laid-Open No. 2002-200000 discloses a technique for dealing with such a case. Patent Document 1 discloses a technique of arranging a ring pattern at a position substantially conjugate with the focal plane of the cornea of the subject's eye so that the specular reflection of the illumination light from the illumination light projection optical system on the cornea does not enter the objective lens. It is

Japanese Patent No. 4504763

The technique disclosed in Japanese Patent Application Laid-Open No. 2002-200000 may not be able to prevent the occurrence of bright spots in a captured image.
SUMMARY OF THE INVENTION It is an object of the present invention to further reduce the possibility of occurrence of bright spots in a photographed image.

In order to achieve the above object, an eye photographing apparatus includes a projection optical system for projecting light from a light source onto the fundus of an eye to be inspected, and photographing optics for photographing the eye illuminated by light reflected from the fundus. and a light shielding unit disposed in the light projecting optical system for blocking a predetermined range including the optical axis of the light passing through the light projecting optical system, wherein the conjugate point of the light source It exists in front of the optometry.

Accordingly, in the eye photographing apparatus, the light shielding portion shields the portion of the light projected onto the eye to be inspected around the optical axis, thereby suppressing the reflected light parallel to the optical axis from the eye to be inspected. In addition, since the conjugate point of the light source is located on the front side of the subject's eye in the traveling direction of the light projected from the projection optical system to the subject's eye, reflected light parallel to the optical axis from the subject's eye is further suppressed. be done. As a result, the eye photographing device can further reduce the possibility of bright spots occurring in the photographed image.

FIG. 2 is a diagram schematically showing an optical system included in an eye imaging device; 3 is a block diagram for explaining the internal configurations of the head section and the main body section; FIG. It is a figure which shows a light-shielding part. 4 is a flowchart showing imaging processing; It is a figure which shows the light projected from a projection optical system. It is a figure which shows the light projected from the projection optical system in a comparative example. FIG. 7A is a diagram for explaining light reflection on the cornea in a comparative example, and FIG. 7B is a diagram for explaining light reflection on the cornea in an eye imaging device. It is a figure which shows the light which injects into an eyeball. FIG. 4 is a diagram for explaining a situation when light is incident on a simulated eye; FIG. 4 is a diagram for explaining a situation when light is incident on a simulated eye; FIG. 4 is a diagram for explaining a situation when light is incident on a simulated eye;

Here, embodiments of the present invention will be described according to the following order.
(1) Configuration of eye imaging device:
(2) Imaging of eye to be examined:
(3) Other embodiments:

(1) Configuration of eye imaging device:
FIG. 1 is a diagram schematically showing an optical system of an eye imaging device 1 according to this embodiment.
The eye photographing device 1 according to one embodiment of the present invention may be configured in various ways. For example, a configuration including a head portion having an optical system and a main body portion can be assumed. For example, the main body is installed on an installation site such as a desk, and the head is relatively movable with respect to the main body. The body section includes a control section that controls each section of the eye imaging apparatus and classifies the state of the examination section. The head section is movable relative to the eye photographing device, and alignment is performed with respect to the subject's eye by movement of the head section. Of course, the aspect of the eye photographing device is an example, and various other aspects may be adopted.

The optical system of the eye photographing device 1 is not particularly limited as long as it is capable of photographing the examination area to be examined. In this embodiment, as shown in the upper right of FIG. 1, up, down, left, right, front and back are expressed based on the direction seen from the subject having the eye E to be examined. The front side of the drawing is the upward direction, and the far side is the downward direction. Note that the eye photographing apparatus 1 according to this embodiment associates these directions with the X direction, the Y direction, and the Z direction. In this embodiment, the front-back direction is the Z-axis direction and the rear is the +Z direction, the vertical direction is the Y-axis direction and the top is the +Y direction, and the left-right direction is the X-axis direction and the left is the +X direction. Of course, the correspondence relationship between each direction and the axis and the positive and negative directions may be different.

The present embodiment can be applied to a plurality of examinations for the subject's eye E, and as part of the examination, there is an examination for examining the turbidity of the lens from the photographed image. The eye photographing device 1 has a function of photographing an image of an eye to be examined for various examinations. The eye photographing device 1 has a function of photographing the subject's eye E by, for example, the transillumination method. In this embodiment, an image is taken with light projected from the front of the eye E to be examined.

FIG. 2 is a block diagram showing the configuration of the eye photographing apparatus 1, focusing on the control of the optical system and the like. The eye photographing device 1 includes a body portion B and a head portion H. As shown in FIG. The body portion B includes an XYZ drive control portion 91 for moving the head portion H in the XYZ directions, and a memory 92 used in control processing of the control portion 90 .

The head portion H also includes a light projecting optical system 10 for projecting light onto the fundus of the eye E to be examined, a photographing optical system 20 for photographing, and an XY alignment system for performing alignment in the XY direction. It has an optical system 30, a Z alignment optical system 40 for performing alignment in the Z direction, and a fixation optical system 50 for realizing a fixation state.

(projecting optical system)
In FIG. 1, each optical system is arranged so that the direction when looking forward from the corneal vertex of the subject's eye E coincides with the optical axis Oc of the photographing optical system 20 extending in the front-rear direction inside the head portion H. showing the position. The optical axis Oc is also the optical axis of the projection optical system 10 at the end on the eye E side to be examined. The projection optical system 10 includes a light source 10a, a lens 10b, a light shielding portion 10c, a half mirror 10d, and a lens 10e. As shown in FIG. 1, a lens 10b, a light blocking portion 10c, and a half mirror 10d are provided on an optical axis O1 extending from a light source 10a. The half mirror 10d is oriented so that the output light from the light source 10a that has passed through the lens 10b and the light shielding portion 10c is reflected in the optical axis Oc direction. The output light of the light source 10a passes through the lens 10b and the light shielding part 10c, is reflected by the half mirror 10d, passes through the lens 10e, and is irradiated to the eye E to be examined. In this embodiment, the light source 10a is a light source that emits infrared light. However, the light source 10a may be a light source that emits other light such as visible light, or may be a light source that emits light including other light such as visible light in addition to infrared light.

The light blocking portion 10c is a disc-shaped member that blocks part of the light from the light source 10a, and is made of a material such as glass or plastic, for example. However, the light shielding portion 10c may be a member having a shape different from the disk shape, such as a rectangular plate shape. The light shielding portion 10c is arranged on the optical axis O1 such that the circular surface is perpendicular to the optical axis O1 and the optical axis O1 passes through the center of the circular surface.

FIG. 3 is a diagram showing the circular surface of the light shielding portion 10c. The circular surface of the light shielding portion 10c includes light shielding areas 101 and 103 coated with light shielding paint and a transmission area 102 through which light is transmitted. The light-shielding region 101 is a circular region of a predetermined size centered on the center of the circular surface of the light-shielding portion 10c. The transmissive area 102 is a ring-shaped area surrounding the light shielding area 101 . The light shielding area 103 is a ring-shaped area surrounding the transmissive area 102 . After passing through the lens 10b, the output light from the light source 10a is blocked by the light blocking regions 101 and 103 of the light blocking portion 10c. The light shielding area 101 shields a circular range around the optical axis O1 from the light from the light source 10a. In addition, the light shielding region 103 shields the light from the light source 10a outside the circle having a predetermined diameter centered on the optical axis O1. Then, the light transmitted through the transmissive region 102 travels to the light shielding portion 10c and beyond.

In this way, the light from the light source 10a is blocked by the light shielding part 10c in the circular region around the optical axis O1, so that the light from the light source 10a is incident near the corneal vertex of the eye E to be examined. Light is blocked, and reflected light from the vicinity of the corneal vertex can be reduced. As a result, it is possible to reduce the possibility of reflected light parallel to the optical axis Oc from near the corneal vertex of the subject's eye E, and as a result, the possibility of the occurrence of bright spots due to such reflected light in the photographed image can be reduced. can be reduced.

In this embodiment, the light shielding part 10c is arranged at a position that is conjugate with the corneal vertex of the eye E to be inspected in the projection optical system 10 . Therefore, the shape of the light transmitted through the transmissive region 102 and the shape of the light at the corneal vertex of the eye E to be examined become the same. As a result, if the light-shielding region 101 is formed in a circle having the same size and shape as the bright spot generated at the corneal vertex, the reflected light from the vicinity of the corneal vertex can be reflected along the optical axis and enter the imaging optical system 20 . By preventing this, it is possible to reduce the possibility of generating a bright spot and prevent excessive light blocking. 5, the projection optical system 10 is adjusted so that the conjugate point C of the light source 10a in the projection optical system 10 is positioned in front of the subject's eye on the optical axis Oc. It is That is, the conjugate point C is located in front of the subject's eye E on the optical axis Oc as viewed from the eye imaging device 1 .

(Photography optical system)
The imaging optical system 20 includes an image sensor 20a and lenses 20b and 10e on an optical axis Oc extending in the front-rear direction. Thus, in the eye imaging device 1, the imaging optical system 20 and the projection optical system 10 share the lens 10e. As a result, the number of lenses to be prepared can be reduced compared to the case where each of the photographing optical system 20 and the projection optical system 10 includes a lens, and the size of the eye photographing apparatus 1 can be reduced. The optical axis Oc is a linear axis that passes through the centers of the imaging element 20a and the lenses 20b and 20c, and is assumed to pass through the corneal vertex when the subject's eye E is aligned at a predetermined position.

When light is projected onto the subject's eye E by the light projecting optical system 10, the projected light hits the fundus of the subject's eye E and is reflected. This reflected light illuminates the subject's eye E from the inside. The light from the eye to be inspected E illuminated in this manner travels along the optical axis Oc, passes through the lenses 10e and 20b, and is received by the imaging element 20a. Thereby, the subject's eye E is photographed. In this embodiment, the imaging element 20a is an imaging element that detects the intensity of each color of RGB (R: red, G: green, B: blue) for each pixel to generate a color image.

In FIG. 1, the lens 20b is represented schematically. The lens 20b in this embodiment is configured by an autofocus mechanism (not shown) that implements an autofocus function. That is, the lens 20b has one or more lenses movable in the direction of the optical axis Oc, and the control unit 90 outputs a control signal to the imaging optical system 20 to form an image of the subject's eye E. The position in the optical axis Oc direction can be changed. In the present embodiment, autofocus is achieved by capturing a plurality of images with the position of the lens 20b changed and acquiring the image with the highest image quality. Image quality should be evaluated such that the better the image quality, the better the in-focus state.

When the photographing is started, the control unit 90 controls the autofocus mechanism including the lens 20b of the photographing optical system 20, and while moving the lens 20b from the predetermined movement start position to the movement end position, the image sensor is moved at a predetermined cycle. 20a is used for photographing. Then, the control unit 90 performs control for focusing on a predetermined area (for example, a rectangular area) including the examination part of the eye E to be examined. In this embodiment, in order to determine the in-focus state based on the image quality, the control unit 90 compares the image quality in the area including the inspection part between the images, acquires the image with the best image quality, and stores it in the memory 92. Record. As a result, it is possible to record an image focused on the inspection area.

Of course, various methods may be adopted for the autofocus method. Thus, according to the configuration capable of autofocusing, it is possible to automatically capture a clear image, which facilitates inspection. In addition, the user can use the image in which the inspecting part is clearly captured without being aware that different positions in the image should be focused according to the difference of the inspecting part. .

(XY alignment optical system)
The XY alignment optical system 30 includes an XY alignment light source 30a, a lens 30b, and a half mirror 30c. In the XY alignment optical system 30, an XY alignment light source 30a, a lens 30b, and a half mirror 30c are arranged in this order from the far side in the direction perpendicular to the optical axis Oc. The XY alignment light source 30a is oriented so that its optical axis is perpendicular to the optical axis Oc. In this embodiment, the optical axis of the XY alignment optical system 30 is parallel to the X axis. That is, each element of the XY alignment optical system 30 (XY alignment light source 30a, lens 30b, half mirror 30c) is arranged parallel to the X axis. However, the optical axis of the XY alignment optical system 30 need not be parallel to the X axis as long as it is perpendicular to the optical axis Oc. For example, the optical axis of the XY alignment optical system 30 may be parallel to the Y axis. That is, each element of the XY alignment optical system 30 may be arranged parallel to the Y axis.

The half mirror 30c is oriented so that the output light from the XY alignment light source 30a that has passed through the lens 30b is reflected in the direction of the optical axis Oc. Therefore, the output light emitted from the XY alignment light source 30a passes through the lens 30b, is reflected by the half mirror 30c, reaches the subject's eye E, and is reflected. Reflected light reflected by the subject's eye E travels along the optical axis Oc, passes through the half mirror 30c, passes through the lens 10e, the half mirror 10d, and the lens 20b, and is received by the imaging element 20a.

In the present embodiment, when the corneal vertex of the subject's eye E exists on the optical axis Oc in the XY plane (in the plane in the vertical and horizontal directions), the output light of the XY alignment light source 30a is imaged. An XY alignment optical system 30 is designed so as to be the reference position (for example, the center) of the element 20a. Therefore, if the relationship between the position of the bright spot detected by the imaging element 20a and the reference position is specified, the XY distance to which the head part H should be moved so that the corneal vertex of the eye E to be examined is on the optical axis Oc can be determined. The direction and amount of movement within the plane can be specified.

Therefore, when performing XY alignment, the control unit 90 controls the XY alignment optical system 30 to turn on the XY alignment light source 30a. The light output from the light source for alignment is hereinafter referred to as alignment light. In this state, the control unit 90 detects the alignment light output from the XY alignment light source 30a by the imaging device 20a provided in the imaging optical system 20. FIG. Then, the control unit 90 refers to the detection result of the alignment light and specifies the movement direction and movement amount of the head unit H. FIG. The XYZ drive control section 91 has a mechanism for moving the head section H together with the optical system in the XYZ directions. Therefore, the control unit 90 instructs the XYZ drive control unit 91 about the direction and amount of movement of the head unit H. FIG. As a result, the head portion H and the internal optical system move integrally and are aligned with the eye E to be examined in the XY direction.

(Z alignment optical system)
The Z alignment optical system 40 includes a Z alignment light source 40a, lenses 40b and 40c, and a position detection sensor 40d. In the Z alignment optical system 40, the Z alignment light source 40a is attached to the head portion H so that the optical axis is oriented in the direction of the angle γ in the horizontal plane with respect to the optical axis Oc. Further, in the Z alignment optical system 40, lenses 40b and 40c and a position detection sensor 40d are arranged in order from the subject's eye E side along an optical axis inclined in the direction of an angle δ in the horizontal plane with respect to the optical axis Oc. there is

In the present embodiment, when the angles γ and δ are the same, and the corneal vertex of the eye to be examined E is on the optical axis Oc and at a predetermined position in the Z direction, the Z alignment light source 40a The Z alignment optical system 40 is designed so that the output light is at the reference position (for example, center) of the position detection sensor 40d. Therefore, if the relationship between the position of the bright spot detected by the position detection sensor 40d and the reference position is specified, the corneal vertex of the subject's eye E is on the optical axis Oc and is at the predetermined position in the Z direction. It is possible to specify the movement direction and movement amount on the Z-axis in which the head unit H should be moved.

Therefore, when performing Z alignment, the control unit 90 controls the Z alignment optical system 40 to turn on the Z alignment light source 40a. In this state, the control unit 90 detects the alignment light output from the Z alignment light source 40a by the position detection sensor 40d. Then, the control unit 90 refers to the detection result of the alignment light and specifies the movement direction and movement amount of the head unit H. FIG. The XYZ drive control unit 91 has a mechanism for moving the head unit H in the XYZ directions by integrating an internal optical system and the like. Therefore, the control unit 90 instructs the XYZ drive control unit 91 about the direction and amount of movement of the head unit H. FIG. As a result, the head portion H and the internal optical system move integrally and are aligned with the subject's eye E in the Z direction.

(Fixation optical system 50)
The fixation optical system 50 includes a fixation light source 50a, a fixation target 50b, a lens 50c, and a half mirror 50d. In the fixation optical system 50, a fixation light source 50a, a fixation target 50b, a lens 50c, and a half mirror 50d are arranged in this order from the far side in the direction perpendicular to the optical axis O1. The fixation light source 50a is oriented so that its optical axis is perpendicular to the optical axis O1. The half mirror 50d is oriented so that the output light of the fixation light source 50a that has passed through the lens 50c and the fixation target 50b is reflected in the direction of the optical axis O1.

The fixation target 50b has a pinhole and a diffusion plate (the diffusion plate may be omitted). In the above configuration, output light emitted from the fixation light source 50a passes through the diffusion plate and pinhole of the fixation target 50b, passes through the lens 50c, is reflected by the half mirror 50d, and reaches the eye E to be examined. and forms an image on the retina of the eye E to be examined. Therefore, the pinhole of the fixation target 50b is conjugate with the position of the fundus of the eye E to be examined. In addition, in the optical system shown in FIG. 1, the arrangement of lenses and the like is a schematic diagram, and may differ from the actual arrangement. The subject's eye E is in a fixation state by fixating on the light that has passed through the fixation target 50b.

(2) Imaging of eye to be examined:
Details of photographing of the subject's eye E by the eye photographing device 1 will be described. FIG. 4 is a flowchart of imaging processing for an eye to be examined. The control unit 90 starts the process of FIG. 4 in a state in which the person to be examined who has the eye E to be examined places the head on the head unit H. As shown in FIG.

In S100, the control unit 90 uses the XY alignment optical system 30 and the Z alignment optical system 40 to align the head portion H with the subject's eye E in a state in which the subject's head is placed on the head portion H. A moving amount and a moving direction for alignment are obtained. Then, the control unit 90 aligns the head unit H with the subject's eye E by moving the head unit H using the XYZ drive control unit 91 based on the obtained movement amount and movement direction.
In S105, the control unit 90 turns on the fixation light source 50a of the fixation optical system 50, and irradiates the subject's eye E with light from the fixation light source 50a, thereby prompting the transition to the fixation state. The person to be examined is in a fixation state by fixating the light irradiated to the eye E to be examined.

In S110, the control unit 90 projects the light L1 output from the light source 10a onto the fundus of the subject's eye E by turning on the light source 10a of the light projecting optical system 10 . That is, the light L1 output from the light source 10a is incident on the subject's eye E through the cornea, and the fundus of the subject's eye E is irradiated with the light. The eye E to be inspected is illuminated by reflected light from the fundus of the eye E to be inspected.
Here, the progress until the light L1 is output from the light source 10a and applied to the subject's eye E will be described with reference to FIG. As shown in FIG. 5, the light L1 output from the light source 10a passes through the lens 10b, and the circular portion centered on the optical axis O1 is blocked by the light blocking portion 10c. The shielded light L1 is reflected by the half mirror 10d and travels in the direction of the subject's eye E on the optical axis Oc. After passing through the lens 10e, the light L1 converges at a conjugate point C of the light source 10a in the projection optical system 10, and then irradiates the cornea of the eye E to be examined. As shown in FIG. 5, in the present embodiment, the projection optical system 10 is adjusted so that the conjugate point C of the light source 10a in the projection optical system 10 is positioned in front of the subject's eye on the optical axis Oc. .

Here, FIG. 6 shows, as a comparative example, a configuration in which the conjugate point C of the light source 10a in the projection optical system 10 is positioned behind the subject's eye on the optical axis Oc. In this case, when the light L1 is incident on the eye to be inspected E, as shown in FIG. 7A, the light L1 is incident toward the corneal vertex of the eye to be inspected E (so as to converge toward the optical axis Oc). Therefore, when the light L1 is reflected by the cornea of the subject's eye E, reflected light R1 may occur in a direction parallel to the optical axis Oc, as shown in FIG. 7A. When such reflected light R1 in a direction parallel to the optical axis Oc enters the imaging optical system 20, bright spots are likely to occur in the captured image.

In contrast, in the present embodiment, the conjugate point C of the light source 10a in the projection optical system 10 is located in front of the subject's eye on the optical axis Oc. In this case, when the light L1 is incident on the eye E to be inspected, it is incident toward the peripheral portion of the cornea of the eye E to be inspected (so as to diffuse from the optical axis Oc), as shown in FIG. 7B. Therefore, the light L1 is reflected by the cornea of the subject's eye E, thereby producing reflected light R2 in a direction away from the optical axis Oc, as shown in FIG. 7B. That is, when the light L1 is reflected by the eye E to be examined, reflected light in a direction parallel to the optical axis Oc is less likely to occur. In this embodiment, the above configuration can reduce the possibility of occurrence of bright spots in the captured image.

Further, in the present embodiment, the conjugate point C of the light source 10a in the projection optical system 10 is adjusted to exist at a position 10 mm or more and 100 mm or less in front of the subject's eye E on the optical axis Oc. As the conjugate point C of the light source 10a in the projection optical system 10 is further away from the eye E to be examined on the optical axis Oc, the light L1 output from the light source 10a and irradiated to the eye E to be examined approaches light parallel to the optical axis Oc. .

Here, with reference to FIG. 8, a case will be described in which the light L1 is incident on the subject's eye E from a position different from the corneal vertex while being parallel to the optical axis Oc. In this case, since the refractive index of the tissue inside the eye E to be examined is higher than the refractive index of air, the angle of refraction β when the light L1 enters the eye E is the angle β when the light L1 enters the eye E. smaller than the incident angle α. Therefore, as shown in FIG. 8, the traveling direction of the light L1′ after incidence is tilted toward the optical axis Oc compared to the light L1 before incidence. As the conjugate point C of the light source 10a in the projection optical system 10 moves away from the eye E to be examined on the optical axis Oc, the state of the light L1 incident on the eye to be examined E becomes parallel to the optical axis Oc as shown in FIG. will come closer. Therefore, if the conjugate point C of the light source 10a in the projection optical system 10 is too far from the eye to be examined E on the optical axis Oc, the light L1 travels so as to converge on the optical axis Oc after entering the eye E to be examined. As a result, the area of the fundus of the subject's eye E irradiated with the light L1 is greatly reduced. In this way, if the conjugate point C is too far from the eye E to be examined, the illuminated area of the fundus of the eye E to be examined becomes very small. It is difficult to uniformly illuminate the subject's eye E with light. FIG. 9A shows a situation in which a simulated eye E' is arranged instead of the subject's eye E, and the conjugate point C is sufficiently separated from the simulated eye E' on the optical axis Oc. FIG. 9B shows the illumination state of the light L1 on the fundus of the simulated eye E′ when simulated eyes with refractive powers of +10D, 0D, and −10D are used as the simulated eye E′ in the situation of FIG. 9A. The colored portions in the figure indicate the regions exposed to the light.

Further, when the position of the conjugate point C of the light source 10a in the light projecting optical system 10 is too close to the subject's eye E, the light L1 from the light source 10a enters the subject's eye E without being spread sufficiently on the XY plane. . Further, the portion of the light L1 around the corneal vertex of the eye to be examined E is shielded by the light shielding portion 10c. Therefore, if the conjugate point C is too close to the eye to be examined E, the radial width of the light L1 incident on the eye to be examined E becomes very narrow. becomes difficult. FIG. 10A shows a situation in which a simulated eye E' is arranged instead of the subject's eye E, and a conjugate point C exists at a position of 7 mm from the simulated eye E' on the optical axis Oc. FIG. 10B shows the illumination state of the light L1 on the fundus of the simulated eye E′ when simulated eyes with refractive powers of +10D, 0D, and −10D are used as the simulated eye E′ in the situation of FIG. 10A.

The inventors photograph the subject's eye E using the imaging optical system 20 while adjusting the position of the conjugate point C of the light source 10a in the projection optical system 10 by adjusting each element in the projection optical system 10. We conducted an experiment to As a result of experiments, the inventors found that when the position of the conjugate point C of the light source 10a in the projection optical system 10 is in the range of 10 mm or more and 100 mm or less in front of the eye E to be examined on the optical axis Oc, We have found that the easier the observation, the clearer the image can be taken. In the present embodiment, based on this knowledge, the projection optical system 10 is arranged so that the conjugate point C of the light source 10a in the projection optical system 10 is located at a position 10 mm or more and 100 mm or less in front of the subject's eye E on the optical axis Oc. 10 have been adjusted.
FIG. 11A shows a situation in which a simulated eye E' is arranged instead of the subject's eye E, and a conjugate point C exists at a position of 15 mm from the simulated eye E' on the optical axis Oc. FIG. 11B shows the illumination state of the light L1 on the fundus of the simulated eye E′ when simulated eyes with refractive powers of +10D, 0D, and −10D are used as the simulated eye E′ in the situation of FIG. 11A. In FIG. 11B, it is shown that a wider area of the fundus is illuminated compared to FIGS. 9B and 10B.

Returning to the description of FIG.
In S115, the control unit 90 uses the imaging element 20a of the imaging optical system 20 to receive the light from the eye E illuminated by the reflected light from the fundus irradiated with the light L1 in S110, image.

With the above configuration, in the eye photographing apparatus 1, the light L1 irradiated to the eye to be inspected E is blocked by the light shielding part 10c in a portion around the optical axis Oc, and light emitted from the vicinity of the corneal vertex parallel to the optical axis Oc is blocked. Reflected light is suppressed. Further, since the conjugate point C of the light source 10a exists in front of the eye E to be examined (on the optical axis Oc, the front side of the eye to be examined E when viewed from the eye photographing apparatus 1), the optical axis Oc from the eye to be examined E Parallel reflected light is further suppressed. Thereby, the eye photographing device 1 can further reduce the possibility of occurrence of bright spots in the photographed image.

(3) Other embodiments:
The above embodiment is an example for carrying out the present invention. Various embodiments can also be adopted. For example, the eye imaging device is not limited to the configuration including the head portion and the body portion as described above, and may be a device including various other elements. The configuration of the optical system is also an example, and various other optical systems may be adopted. For example, the eye imaging device may comprise an optical system different from the optical system described in the above embodiments. The eye imaging apparatus includes, for example, a slit projection optical system that projects slit light onto the subject's eye, an illumination optical system that projects white light and blue light onto the subject's eye, an infrared optical system that projects infrared light onto the subject's eye, and the like. You may prepare. The eye imaging device may be a device combined with a device for measuring eye characteristics such as eye refractive power, corneal curvature, corneal shape and intraocular pressure.

In the above-described embodiment, the light shielding area 101 of the light shielding part 10c is a circular area centered on the optical axis Oc. However, the light shielding area 101 may be an area having another shape such as a rectangular shape or a triangular shape as long as the area includes the optical axis Oc.
Further, in the above-described embodiment, the light shielding part 10c is arranged at a position conjugate with the corneal vertex of the eye E to be examined in the projection optical system 10 . However, the light shielding part 10c may be arranged at a position conjugate with other parts of the subject's eye E in the projection optical system 10 . For example, the light shielding part 10c may be arranged at a position conjugate with a portion behind the corneal vertex of the eye E to be inspected by a predetermined distance (for example, 1 mm).

Further, in the above-described embodiment, the light shielding part 10c is arranged at a position conjugate with the corneal vertex of the eye E to be examined in the projection optical system 10 . However, the light shielding part 10c may be arranged at a position that is not conjugated to any part of the eye E in the projection optical system 10 .
Further, in the above-described embodiment, the light shielding portion 10c is a disk-shaped member with a coated surface. However, the light shielding portion 10c may be another member such as a non-transmissive disk-shaped member fitted in the hollow portion of a transparent ring-shaped member.

In the above-described embodiment, the projection optical system 10 is adjusted so that the conjugate point of the light source 10a in the projection optical system 10 is located at a position within 10 mm or more and 100 mm or less from the subject's eye E on the optical axis Oc. However, the light projecting optical system 10 is adjusted so that the conjugate point of the light source 10a in the light projecting optical system 10 exists on the optical axis Oc at either a position less than 10 mm from the subject's eye E or a position farther than 100 mm. good too.

Further, in the above-described embodiment, the projection optical system 10 and the imaging optical system 20 share the lens 10e, which is a part of the optical element. However, the projection optical system 10 and the imaging optical system 20 do not have to share an optical element. In that case, for example, a half mirror is provided between the eye to be examined E and the lens 10e on the optical axis Oc, and the light along the optical axis Oc coming from the eye to be examined E is perpendicular to the optical axis Oc by this half mirror. reflect in any direction. A photographing optical system may be provided along the traveling direction of the light reflected by the half mirror.

The light shielding portion may shield a circular range centered on the optical axis. Since the eyeball has a substantially spherical shape, a range in which reflected light parallel to the optical axis is likely to occur spreads circularly around the intersection of the optical axis of the projected light and the eye to be examined. Therefore, when a range of a shape different from a circle, such as a rectangle, is shaded by the light shielding portion, even light with a very small possibility of causing reflected light is shielded. The light shielding portion shields a circular range centered on the optical axis, thereby reducing the possibility of occurrence of such a situation.
The imaging optical system may receive the light coming from the subject's eye along the optical axis of the light projected from the projection optical system and take an image.

DESCRIPTION OF SYMBOLS 1... Eye imaging device 10... Projection optical system 10a... Light source 10b... Lens 10c... Light shielding part 10d... Half mirror 10e... Lens 20... Photographing optical system 20a... Imaging element 20b... Lens, 30... XY alignment optical system, 30a... XY alignment light source, 30b... lens, 30c... half mirror, 40... Z alignment optical system, 40a... Z alignment light source, 40b... lens, 40c... lens, 40d Position detection sensor 50 Fixation optical system 50a Fixation light source 50b Fixation target 50c Lens 50d Half mirror 90 Control unit 91 XYZ drive control unit 92 Memory H... head part, B... body part, Oc... optical axis, O1... optical axis, L1... light

Claims (4)

a projection optical system that projects light from a light source onto the fundus of the eye to be examined;
a photographing optical system for photographing the subject's eye illuminated by reflected light from the fundus;
a light shielding unit arranged in the light projecting optical system for blocking a predetermined range including an optical axis out of the light passing through the light projecting optical system;
with
The eye photographing apparatus in which the conjugate point of the light source exists in front of the eye to be examined. 2. The eye photographing apparatus according to claim 1, wherein the light shielding part is located at a position conjugated to a predetermined position of the eye to be inspected in the projection optical system. 3. The eye photographing apparatus according to claim 2, wherein said predetermined position is the position of the corneal vertex of said eye to be examined. 4. The conjugate point of the light source is located at a position 10 mm or more and 100 mm or less from the eye to be examined on the optical axis of the light projected onto the eye by the projection optical system. 1. An eye photographing device according to any one of claims 1 to 3.

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