CN115460970B - Fundus photography device - Google Patents

Abstract

A fundus photography device comprises: a projector which performs two-dimensional scanning on a photographic light beam used for fundus photography and then emits it; a first optical component which causes a plurality of photographic light beams emitted from the projector at different times to converge at a first convergence point near a pupil of a subject and then illuminate the subject's retina; a second optical component which causes a plurality of first reflected light beams which are reflected by the subject's retina and pass through the first optical component to converge at a second convergence point; a simulated eye optical system which is arranged at the second convergence point and converts the plurality of first reflected light beams into converged light beams respectively; a light detector which detects the plurality of first reflected light beams which pass through the simulated eye optical system; and an image generating unit which generates a fundus image based on an output signal of the light detector.

Description

Fundus imaging device

Technical Field

The present invention relates to a fundus imaging apparatus.

Background

An ophthalmic apparatus is known in which an optical system for guiding incident light for fundus imaging to a retina of a subject and guiding reflected light from the retina of the subject to a photodetector is incorporated into an optical system for guiding scanning light for treatment or optotype to the retina of the subject (for example, patent literature 1). Further, a Scanning Laser Ophthalmoscope (SLO) is known which irradiates a retina of a subject after scanning light rays, and acquires a fundus image by detecting reflected light rays from the retina using a photodetector.

Prior art literature

Patent literature

Patent document 1 Japanese patent application laid-open No. 2011-512916

Disclosure of Invention

Problems to be solved by the invention

A projector is known that projects an image by two-dimensionally scanning light and then projecting the scanned light to the outside. In the case of constructing an ophthalmic device using such a projector, it is required to acquire a fundus image using light emitted from the projector after being two-dimensionally scanned.

The present invention has been made in view of the above-described problems, and an object thereof is to enable fundus images to be acquired.

Means for solving the problems

A fundus imaging apparatus includes a projector that two-dimensionally scans and emits imaging light rays for fundus imaging, a first optical member that causes a plurality of imaging light rays emitted from the projector at different times to converge at a first convergence point near a pupil of a subject and then irradiate the subject's retina, a second optical member that causes a plurality of first reflection light rays reflected by the subject's retina and transmitted through the first optical member to converge at a second convergence point, an eye-simulating optical system that is disposed at the second convergence point and converts the plurality of first reflection light rays into converging light rays, respectively, a photodetector that detects the plurality of first reflection light rays transmitted through the eye-simulating optical system, and an image generating unit that generates an image from an output signal of the photodetector.

In the above configuration, the first convergence point and the second convergence point may be located at substantially conjugate positions, and the retina of the subject may be located at substantially conjugate positions with the photodetector.

In the above configuration, the first optical member may converge the plurality of photographing lights at the first convergence point and convert the plurality of photographing lights from diffused light to substantially parallel light, the second optical member may converge the plurality of first reflected lights at the second convergence point and convert the plurality of first reflected lights from diffused light to substantially parallel light, and the pseudo-eye optical system may convert the plurality of first reflected lights from substantially parallel light to converged light.

In the above configuration, the imaging device may further include a third optical member disposed between the first optical member and the second optical member, wherein the plurality of imaging light rays emitted from the projector at different times are reflected by the third optical member and are incident on the first optical member, and the plurality of first reflected light rays reflected by the retina of the subject are transmitted through the first optical member and the third optical member and are incident on the second optical member.

In the above configuration, the optical system may be configured to include a 1/4 wavelength plate disposed between the third optical member and the first optical member, and the third optical member may be a polarizing beam splitter.

The above-described structure may be configured to include a light source that emits a background light that irradiates the retina of the subject, and a fourth optical member that is disposed between the first optical member and the second optical member, wherein the background light emitted from the light source is reflected by the fourth optical member and irradiates the retina of the subject through the first optical member.

In the above configuration, a fifth optical member may be provided, which is disposed between the second optical member and the artificial eye optical system and bends the plurality of first reflected light rays.

In the above configuration, the focal length of the first optical member may be different from the focal length of the second optical member.

In the above configuration, the imaging device may be configured such that, when the imaging light is irradiated to the first region and the second region of the first region and the second region obtained by dividing the retina of the subject into two parts with respect to the center of the retina, the imaging light is not irradiated to the second region, and when the imaging light is irradiated to the second region, the imaging light is not irradiated to the first region, a light shielding member is movably disposed between the second optical member and the second convergence point, and a driving mechanism moves the light shielding member to a first position where the imaging light is reflected by the cornea of the subject and the first reflected light of the first optical member passes through the first optical member and the second optical member, and when the imaging light is irradiated to the second region, the light shielding member is movably disposed between the second optical member and the second convergence point, and generates an image based on the two-position generated by the two-position image-generated by the imaging light reflected by the second optical member.

In the above configuration, the light shielding member may be disposed at or near a focal point of the second reflected light beam in front of the second convergence point.

In the above configuration, the light shielding member may be movable in a first direction in which the second reflected light is incident on the light shielding member and a second direction intersecting the first direction.

In the above configuration, the second reflecting light beam may have a center portion of the light shielding member having a コ -shaped concave shape.

In the above configuration, the simulated eye optical system, the photodetector, and the image generating unit may be digital cameras.

In the above configuration, the projector may be a general purpose projector that can be attached and detached.

In the above configuration, the distance from the second convergence point to the photodetector may be a distance based on the length from the surface of the cornea of the subject to the surface of the retina of the subject, and may be in the range of 16mm to 17 mm.

In the above configuration, the plurality of photographing lights emitted from the projector may be vertically polarized lights, the fundus photographing device may include a polarizing plate that transmits the vertically polarized lights, the third optical member may be a polarizing beam splitter that reflects the vertically polarized lights and transmits lights other than the vertically polarized lights, the third optical member may transmit the plurality of first reflected lights of random polarized lights reflected by the retina of the subject after the vertically polarized lights pass through the cornea of the subject, and reflect the vertically polarized lights reflected by the cornea of the subject, and the photodetector may detect the plurality of first reflected lights of random polarized lights transmitted through the third optical member.

In the above configuration, the plurality of photographing lights emitted from the projector may be unpolarized lights, and the polarizing plate may transmit the unpolarized lights as vertically polarized lights.

The invention provides an image forming apparatus, which is characterized by comprising a light source for emitting photographing light for fundus photographing, a first optical component for converging the photographing light at a first convergence point near the pupil of a subject and then irradiating the photographing light to the retina of the subject, a second optical component for converging the photographing light at a second convergence point by the first reflection light reflected by the retina of the subject and transmitted through the first optical component, a photodetector for detecting the first reflection light transmitted through the second optical component, and an irradiation region adjusting part for not irradiating the photographing light to the second region when irradiating the photographing light to the first region and the second region which are obtained by dividing the retina of the subject into two parts relative to the center of the retina;

And a driving mechanism that moves the light shielding member to a first position where the photographing light is reflected by the cornea of the subject and transmitted through the first optical member and the second optical member and the first reflected light passes through, and moves the light shielding member to a second position where the second reflected light is blocked and the first reflected light passes through, when the photographing light is irradiated only to the second region, and an image generating unit that generates an image based on an output signal of the photodetector, and synthesizes the two generated images to generate a fundus image, when the photographing light is irradiated only to the first region.

Effects of the invention

According to the present invention, a fundus image can be acquired.

Drawings

Fig. 1 is a block diagram of a fundus imaging apparatus of embodiment 1.

Fig. 2 is a diagram showing an optical system of the fundus imaging apparatus of embodiment 1.

Fig. 3 is a diagram showing an analog ocular optical system.

Fig. 4 is a diagram showing light scanning on the retina of the subject.

Fig. 5 is a flowchart showing an example of fundus imaging processing.

Fig. 6 is a diagram showing an optical system of the fundus imaging apparatus of embodiment 2.

Fig. 7 is a diagram showing an optical system of the fundus imaging apparatus of embodiment 3.

Fig. 8 is a diagram showing an optical system of the fundus imaging apparatus of embodiment 4.

Fig. 9 (a) is an external perspective view of the fundus imaging apparatus according to example 5, fig. 9 (B) is an external perspective view as seen along arrow a in fig. 9 (a), and fig. 9 (c) is an external perspective view as seen along arrow B in fig. 9 (a).

Fig. 10 is a diagram showing an optical system of the fundus imaging apparatus of embodiment 5.

Fig. 11 is a diagram showing a trajectory of light reflected by the cornea of the subject.

Fig. 12 (a) is a diagram showing a trajectory of light reflected by the retina, and fig. 12 (b) is a diagram enlarging the vicinity of the pseudo-eye optical system of fig. 12 (a).

Fig. 13 (a) is a diagram showing the trajectory of light reflected by the cornea, and fig. 13 (b) is a diagram enlarging the vicinity of the pseudo-eye optical system of fig. 13 (a).

Fig. 14 (a) is a diagram showing only the optical axis of the light ray of fig. 13 (a), and fig. 14 (b) and 14 (c) are diagrams showing the trajectories of 2 light rays out of the 3 light rays of fig. 13 (a).

Fig. 15 is a block diagram of a fundus imaging apparatus of embodiment 6.

Fig. 16 (a) to 16 (d) are diagrams showing an optical system of the fundus imaging apparatus of embodiment 6;

fig. 17 is a diagram showing an example of a retinal reflected light ray having a half-divided shape.

Fig. 18 is a flowchart showing an example of fundus imaging processing.

Fig. 19 (a) and 19 (b) are diagrams showing an optical system of the fundus imaging apparatus according to modification 1 of embodiment 6.

Fig. 20 (a) to 20 (c) are diagrams showing a change in the position of the focal point of the cornea reflected light caused by a difference in the radius of curvature of the cornea.

Fig. 21 is a view showing an example of a case where a light shielding plate disposed on a virtual plane has a コ -shaped configuration.

Fig. 22 (a) and 22 (b) are diagrams showing problems that occur when a flat-type light shielding plate is used to shield cornea reflected light.

Fig. 23 is a diagram showing an optical system of the fundus imaging apparatus of embodiment 7.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Example 1

Fig. 1 is a block diagram of a fundus imaging apparatus of embodiment 1. Referring to fig. 1, fundus imaging apparatus 100 includes projection unit 10, control unit 30, and photodetector 40. The fundus imaging apparatus 100 may be provided with the display portion 41 detachably or integrally. The projector 10 includes a light source 11, a scanner 12, an optical system 13, a driving circuit 14, and an input circuit 15. The control unit 30 includes an image control unit 31, a signal processing unit 32, and an image generation unit 33. The light source 11, the scanning unit 12, the driving circuit 14, the input circuit 15, and the image control unit 31 are provided in a projector 16 that performs two-dimensional scanning of light and then emits the light to the outside. The projector 16 is, for example, a general laser scanning projector.

The image control unit 31 generates an image projected onto the retina of the subject. The image control unit 31 inputs an image signal to the input circuit 15. The driving circuit 14 drives the light source 11 and the scanner 12 based on the control signal of the image control unit 31 and the image signal acquired by the input circuit 15.

The light source 11 may emit invisible light as infrared laser light, may emit visible light of a single wavelength of red laser light, green laser light, or blue laser light, or may emit white light including the same. The wavelength of the infrared laser can be 785 nm-1.4 μm, the wavelength of the red laser can be 610nm-660 nm, the wavelength of the green laser can be 515 nm-540 nm, and the wavelength of the blue laser can be 440 nm-480 nm.

The scanning unit 12 is, for example, a scanning mirror such as a MEMS (Micro Electro MECHANICAL SYSTEM: micro Electro mechanical system) mirror or a transmissive scanner, and performs two-dimensional scanning of the light beam 50 emitted from the light source 11.

The optical system 13 irradiates the light ray 50 after the two-dimensional scanning to the eye 70 of the subject. The reflected light ray 51 reflected by the retina of the subject's eye 70 is incident on the photodetector 40 via the optical system 13. The photodetector 40 detects the reflected light 51. The photodetector 40 includes an image pickup element such as a CMOS (Complementary Metal Oxide Semiconductor: complementary metal oxide semiconductor) image sensor or a CCD (Charge Coupled Device: charge coupled device) image sensor, for example.

The signal processing unit 32 processes the output signal of the photodetector 40 based on the control signal of the image control unit 31. The image generating unit 33 generates a fundus image from a signal obtained by processing the output signal of the photodetector 40 by the signal processing unit 32. The display unit 41 is, for example, a liquid crystal display, and displays the image generated by the image generating unit 33.

The image control unit 31, the signal processing unit 32, and the image generation unit 33 may be configured to perform processing in cooperation with a program by a processor such as a CPU (Central Processing Unit: central processing unit), for example. The image control unit 31, the signal processing unit 32, and the image generation unit 33 may be specially designed circuits. The image control unit 31, the signal processing unit 32, and the image generation unit 33 may be 1 circuit or may be different circuits.

Fig. 2 is a diagram showing an optical system of the fundus imaging apparatus of embodiment 1. In fig. 2, the light ray 50 and the reflected light ray 51 are represented by the respective limited beam diameters, and the centers thereof are represented by broken lines. Referring to fig. 2, projector 16 includes light source 11, scanner 12, collimator lens 17, mirror 18, optical member 19, and attenuation filter 20. The light source 11, the scanner 12, the collimator lens 17, and the reflecting mirror 18 are disposed in the housing 29. The optical member 19 and the attenuation filter 20 are mounted on the outside of the housing 29. The optical member 19 and the attenuation filter 20 may be disposed in the housing 29, or may be disposed separately from the housing 29 without being disposed in the projector 16. The light beam 50 emitted from the light source 11 is converted from diffuse light to substantially parallel light by the collimator lens 17, and then reflected by the reflecting mirror 18 to enter the scanning unit 12. The substantially parallel light includes not only the case of completely parallel light but also the case of slightly converging or diffusing.

The light 50 after the two-dimensional scanning by the scanning unit 12 passes through the optical member 19 and the attenuation filter 20. The optical member 19 is, for example, a condenser lens, and converts a plurality of light rays 50 emitted from the scanner unit 12 at different times and having mutually diffused optical axes into a plurality of light rays 50 having mutually substantially parallel optical axes, and converts each light ray 50 from substantially parallel light to condensed light. The plurality of light rays 50 emitted from the scanner unit 12 at different times may be collectively referred to as scanning light. The attenuation filter 20 is, for example, an ND filter, and adjusts the light quantity of the light ray 50. The projector 16 may be provided with a plurality of attenuation filters 20 having different amounts of adjustment of the light quantity, and may be configured to switch the attenuation filters 20 through which the light 50 passes. This allows the amount of light 50 emitted from projector 16 to be appropriately changed according to the application and the like.

The plurality of light rays 50 emitted from the projector 16 are reflected by the optical member 21 and are incident on the optical member 22. The optical member 21 is a half mirror. The light rays 50 are diffused light after focusing in front of the optical member 22, and are incident on the optical member 22. The optical member 22 is, for example, a condenser lens, and converts a plurality of light rays 50 whose optical axes are substantially parallel to each other into a plurality of light rays 50 whose optical axes are mutually converged, and converts each light ray 50 from diffuse light into substantially parallel light. The substantially parallel light here may be substantially parallel light to the extent that the light ray 50 can be focused substantially on the retina 74 of the subject, and includes substantially parallel light when only parallel light is described. The plurality of light rays 50 transmitted through the optical member 22 are converged at the convergence point 52 near the pupil 71 of the subject's eye 70, and are irradiated to the retina 74 through the lens 72 and the vitreous body 73. The beam diameter (diameter) of each light ray 50 when it is incident on the cornea 75 is about 0.8mm to 1.65 mm. Each ray 50 is converted by the lens 72 from a substantially parallel light to a converging light that is focused substantially at the retina 74. Thus, the light ray 50 is observed by maxwell to be irradiated to the retina 74 of the subject.

The light ray 50 is reflected by the retina 74 of the subject. The reflected light ray 51 reflected by the retina 74 passes through the optical member 22 and the optical member 21, and is incident on the optical member 23. The optical member 22 converts the plurality of reflected light rays 51 having optical axes reflected by the retina 74 that are mutually diffused into a plurality of reflected light rays 51 having optical axes that are substantially parallel to each other, and converts each of the reflected light rays 51 from substantially parallel light into converging light. The reflected light ray 51 is focused in front of the optical member 23, and then enters the optical member 23 as diffused light. The optical member 23 is, for example, a condenser lens, and converts a plurality of reflected light rays 51 whose optical axes are substantially parallel to each other into a plurality of reflected light rays 51 whose optical axes are mutually converged, and converts each of the reflected light rays 51 from diffuse light into substantially parallel light.

The pseudo-eye optical system 24 is disposed at a convergence point 53 at which the plurality of reflected light rays 51 transmitted through the optical member 23 converge. The pseudo-eye optical system 24 is composed of a plurality of lenses, and converts the reflected light ray 51 from substantially parallel light to converging light. After being converted into converging light by the pseudo-eye optical system 24, the reflected light ray 51 is focused on a detection surface (imaging surface) 40a of the photodetector 40 having a planar shape or in the vicinity of the detection surface 40 a. The scanning section 12, the convergence point 52, and the convergence point 53 are located at substantially conjugate positions. The substantially conjugated position includes a case where the manufacturing error is deviated from the conjugated position, and includes a case where the position is merely conjugated.

Fig. 3 is a diagram showing an analog ocular optical system. In fig. 3, the center of the finite beam diameter of the reflected light ray 51 is indicated by a broken line. Referring to fig. 3, the pseudo-eye optical system 24 is constituted by, for example, a convex lens 24a, a concave lens 24b, and a convex lens 24 c. The reflected light ray 51 is converted from substantially parallel light to converging light by the convex lens 24a, from converging light to diffuse light by the concave lens 24b, from diffuse light to converging light again by the convex lens 24c, and is focused on the detection surface 40a or the vicinity of the detection surface 40a of the photodetector 40. The convex lens 24a is a plano-convex lens having a convex surface on the side on which the reflected light ray 51 enters and a flat surface on the side on which the reflected light ray exits. The concave lens 24b is a biconcave lens having concave surfaces on both the incident side and the outgoing side of the reflected light ray 51. The convex lens 24c is a plano-convex lens in which the surface on the side on which the reflected light ray 51 enters is a plane surface and the surface on the side on which the reflected light ray exits is a convex surface. The convex lenses 24a and 24c may be a double convex lens having both surfaces of the incident side and the outgoing side of the reflected light beam 51 as convex surfaces. The concave lens 24b may be a plano-concave lens in which one of the incident side and the emergent side of the reflected light ray 51 is concave and the other is flat.

The convex lens 24a is disposed in contact with the concave lens 24 b. The concave lens 24b is disposed apart from the convex lens 24 c. The convex lens 24a and the concave lens 24b may be arranged at a distance narrower than the distance between the concave lens 24b and the convex lens 24 c. The plurality of reflected light rays 51 are converged at, for example, a center portion of a convex surface of the convex lens 24a, into which the reflected light rays 51 are incident, to form a convergence point 53.

The length L from the convex surface or convergence point 53 of the convex lens 24a to the detection surface 40a of the photodetector 40 corresponds to a distance obtained by correcting the length L from the surface of the lens of the eye or the surface of the cornea to the surface of the retina in consideration of the refractive index of the eye, and is, for example, 16mm to 17mm.

The optical member 21, the optical member 22, the optical member 23, and the pseudo-eye optical system 24 in fig. 2 correspond to the optical system 13 in fig. 1. The optical member 22 and the optical member 23 may be the same members as the optical member 19 provided in the projector 16. By providing the optical member 22 and the optical member 23 as the same member, manufacturing cost can be reduced. The optical component 21, the optical component 22, the optical component 23, the pseudo-eye optical system 24, and the photodetector 40 are provided as an integrated optical system module, and a detachable portion is provided so as to be detachable from the projector 16, whereby the optical system module and the projector 16 can be detached and replaced. Thus, if the projector 16 is a general-purpose projector projected onto a wall, a screen, or the like, the general-purpose projector can be used as a fundus imaging apparatus by connecting it to the optical system module.

Fig. 4 is a diagram showing scanning of light rays on the retina of the subject. Referring to fig. 4, the scanning section 12 raster scans the light ray 50 from the upper left to the lower right as indicated by an arrow 55 on the retina 74. If the light source 11 does not emit the light ray 50 even if the scanning section 12 is driven, the light ray 50 does not irradiate the retina 74. For example, the arrow 55 in dashed lines in fig. 4 does not emit the light 50. The driving circuit 14 synchronizes the emission of the light 50 from the light source 11 and the driving of the scanning section 12. Thus, the light source 11 emits the light ray 50 within a predetermined range (the real arrow 55) on the retina 74.

Fig. 5 is a flowchart showing an example of fundus imaging processing. Referring to fig. 5, the image control unit 31 controls driving of the light source 11 and the scanner unit 12, and emits light 50 for fundus imaging from the projector 16, so that the light 50 is irradiated to the retina 74 (step S10). The light 50 used for fundus imaging may be an infrared laser, white light including red, green, and blue lasers, or monochromatic light including a single-wavelength laser. In the fundus photographing process of fig. 5, the light ray 50 is raster-scanned from the upper left to the lower right on the retina 74 and then irradiated to the entire retina 74. As illustrated in fig. 2, when the light ray 50 is irradiated to the retina 74 of the subject, the reflected light ray 51 reflected by the retina 74 is incident on the photodetector 40.

Next, the signal processing unit 32 acquires an output signal of the photodetector 40 (step S12). Next, the image generating unit 33 generates a fundus image based on the signal obtained by processing the output signal of the photodetector 40 by the signal processing unit 32 (step S14). The display section 41 displays the fundus image generated by the image generating section 33 (step S16). The doctor can check the fundus state of the subject by examining the fundus image displayed on the display portion 41.

According to embodiment 1, as shown in fig. 2, a plurality of light rays 50 (photographing light rays) for fundus photographing emitted from the projector 16 at different times are converged by the optical member 22 (first optical member) at the convergence point 52 (first convergence point) near the pupil 71 of the subject and then irradiated to the retina 74 of the subject. The plurality of reflected light rays 51 (first reflected light rays) reflected by the retina 74, after having transmitted through the optical member 22, are converged at a convergence point 53 (second convergence point) by the optical member 23 (second optical member). At the convergence point 53, the pseudo-eye optical system 24 that converts the reflected light ray 51 into converged light is arranged. The plurality of reflected light rays 51 are detected by the photodetector 40 after having transmitted through the simulated eye optical system 24. The image generation unit 33 generates a fundus image based on the output signal of the photodetector 40. In this way, in the fundus imaging apparatus 100 configured by using the projector 16 which performs two-dimensional scanning of the light beam 50 and then emits the light beam, a fundus image can be acquired.

In order to irradiate the light ray 50 to the retina 74 of the subject by maxwell observation, the reflected light ray 51 of the light ray 50 reflected by the retina 74 is detected by the photodetector 40, and it is preferable that the convergence point 52 and the convergence point 53 are at substantially conjugate positions. In order to focus the light ray 50 on the retina 74 of the subject and focus the reflected light ray 51 on the detection surface 40a of the photodetector 40, it is preferable that the retina 74 of the subject and the photodetector 40 be at substantially conjugate positions. The substantially conjugate position also includes a case where the position is deviated from the conjugate position by the degree of manufacturing error.

As shown in fig. 2, the optical component 22 converges the plurality of light rays 50 at a convergence point 52 and converts each light ray 50 from diffuse light to substantially parallel light. This can focus the light ray 50 on the retina 74 of the subject. The optical member 23 condenses the plurality of reflected light rays 51 at the condensing point 53, and converts each reflected light ray 51 from diffuse light to substantially parallel light, and the pseudo-eye optical system 24 converts the reflected light ray 51 of substantially parallel light to condensed light. This can focus the reflected light ray 51 on the detection surface 40a of the photodetector 40.

Preferably, the light ray 50 emitted from the projector 16 is reflected by the optical member 21 (third optical member) disposed between the optical member 22 and the optical member 23, and is incident on the optical member 22, and the reflected light ray 51 reflected by the retina 74 is transmitted through the optical member 22 and the optical member 21, and is incident on the optical member 23. Thus, the fundus imaging apparatus 100 can be miniaturized.

Example 2

Since the block diagram of the fundus imaging apparatus of embodiment 2 is the same as that of fig. 1 of embodiment 1, the explanation thereof is omitted. Fig. 6 is a diagram showing an optical system of the fundus imaging apparatus of embodiment 2. Referring to fig. 6, in fundus imaging apparatus 200 according to embodiment 2, 1/4 wavelength plate 25 is disposed between optical member 21a and optical member 22. The optical member 21a is a polarizing beam splitter. Other structures are the same as those of embodiment 1, and therefore, description thereof is omitted.

According to embodiment 2, the optical member 21a is a polarizing beam splitter, and a 1/4 wavelength plate 25 is disposed between the optical member 21a and the optical member 22. Thus, when the light beam 50 of the S wave is emitted from the projector 16, the light beam 50 is reflected by the optical member 21a, and passes through the 1/4 wavelength plate 25 to be circularly polarized light, thereby irradiating the retina 74 with the circularly polarized light. The reflected light ray 51 reflected by the retina 74 becomes a P-wave by passing through the 1/4 wavelength plate 25, and passes through the optical member 21a to enter the optical member 23. By adopting such a configuration, the light utilization efficiency can be improved, and the optical S/N ratio can be improved.

Example 3

Since the block diagram of the fundus imaging apparatus of embodiment 3 is the same as that of fig. 1 of embodiment 1, the explanation thereof is omitted. Fig. 7 is a diagram showing an optical system of the fundus imaging apparatus of embodiment 3. Referring to fig. 7, in fundus imaging apparatus 300 of embodiment 3, optical member 19 and optical member 23 are the same member, but the focal length of optical member 22a is shorter than the focal lengths of optical members 19 and 23. Other structures are the same as those of embodiment 1, and therefore, description thereof is omitted.

According to embodiment 3, the focal length of the optical member 22a is shorter than that of the optical member 23. Thus, the FOV (Fieldof View: field angle) is enlarged, and the range of the light ray 50 irradiated to the retina 74 can be enlarged.

In embodiment 3, the case where the focal length of the optical member 22a is shorter than that of the optical member 23 is exemplified, but may be long. In this case, since the beam diameter when the light ray 50 is incident on the cornea of the subject can be increased, the spot diameter of the light ray 50 on the retina 74 becomes small, and the resolution on the retina 74 and the SN ratio of the fundus image can be improved. In this way, the focal length of the optical member 22a can be made different from that of the optical member 23 depending on the FOV and the point of the beam diameter at the time of cornea incidence.

Example 4

Since the block diagram of the fundus imaging apparatus of embodiment 4 is the same as that of fig. 1 of embodiment 1 except for the point where the light source 26 is added, the explanation thereof is omitted. Fig. 8 is a diagram showing an optical system of the fundus imaging apparatus of embodiment 4. Referring to fig. 8, fundus imaging apparatus 400 according to embodiment 4 includes light source 26 for emitting background light 54 and optical member 27 disposed between optical member 21 and optical member 22, in addition to the configuration of fig. 2 according to embodiment 1. The light source 26 is, for example, an LED light source or a laser light source. The optical member 27 is, for example, a half mirror. The backlight 54 emitted from the light source 26 is reflected by the optical member 27 and enters the optical member 22. The back light 54 is converted from diffuse light to converging light by the optical member 22, focused near the pupil 71 of the subject, and then irradiated to the retina 74. The background light 54 from the light source 26 is emitted, for example, by the inspector turning on the light source 26. Other structures are the same as those of embodiment 1, and therefore, description thereof is omitted.

According to embodiment 4, the light source 26 that emits the background light 54 is provided. Only by the light ray 50, a satisfactory fundus image may not be obtained due to unevenness caused by insufficient light amount and/or scanning, and generation of stray light. By providing the light source 26, the background light 54 is irradiated to the retina 74, and the brightness of the entire retina 74 is improved, so that a good fundus image can be obtained. At this time, an optical member 27 (fourth optical member) is disposed between the optical member 22 and the optical member 23, and the background light 54 emitted from the light source 26 is reflected by the optical member 27 and is irradiated to the retina 74 of the subject through the optical member 22. Therefore, the fundus imaging apparatus 400 can be prevented from becoming large.

Example 5

Fig. 9 (a) is an external perspective view of the fundus imaging apparatus of example 5, fig. 9 (B) is an external perspective view viewed along arrow a of fig. 9 (a), and fig. 9 (c) is an external perspective view viewed along arrow B of fig. 9 (a). Referring to fig. 9 (a) to 9 (c), a fundus imaging apparatus 500 according to embodiment 5 is a hand-held fundus imaging apparatus, and includes a housing 90 having a projection unit 10, a control unit 30, and a photodetector 40 therein, and a lens barrel 91 for aligning an eye 70 of a subject. The width W of the fundus imaging apparatus 500 is 70mm to 80 mm. The depth D1 is 90mm to 100mm, and D2 is 60mm to 70 mm. The height H is 150 mm-160 mm.

Fig. 10 is a diagram showing an optical system of the fundus imaging apparatus of embodiment 5. Referring to fig. 10, in fundus imaging apparatus 500 according to embodiment 5, optical member 28 for bending reflected light ray 51 is disposed between optical member 23 and pseudo-eye optical system 24. The optical component 28 is, for example, a mirror. Therefore, the reflected light ray 51 transmitted through the optical member 23 is reflected and bent by the optical member 28 and then enters the pseudo-eye optical system 24.

The angle at which the direction in which the optical member 22 faces the optical member 23 and the direction in which the light ray 50 is emitted from the projector 16 intersect is not a right angle. When the virtual plane including the emission surface of the light ray 50 of the projector 16 is used as the reference plane, the optical member 22 is disposed farther from the virtual plane than the optical member 23. Therefore, the light ray 50 emitted from the projector 16 is reflected by the optical member 21 obliquely upward in a direction away from the projector 16, and is incident on the optical member 22. Other structures are the same as those of embodiment 1, and therefore, description thereof is omitted.

According to embodiment 5, an optical member 28 (fifth optical member) that bends the reflected light ray 51 is arranged between the optical member 23 and the pseudo-eye optical system 24. Thus, the fundus imaging apparatus 500 can be miniaturized. For example, in fig. 10, the circuits of the signal processing unit 32 and the image generating unit 33 can be arranged below the photodetector 40, and the fundus imaging apparatus 500 can be miniaturized.

The light emitted from the projector 16 is reflected by the optical member 21 obliquely upward away from the projector 16, and is incident on the optical member 22. As a result, as shown in fig. 9 (c), the lens barrel 91 can be oriented obliquely upward, and the subject can easily align the eye 70 with the lens barrel 91.

Example 6

As shown in fig. 2, the light 50 emitted from the projector 16 is irradiated to the retina 74 through the cornea 75. Thus, a portion of light 50 is reflected by cornea 75. Fig. 11 is a diagram showing a trajectory of light reflected by the cornea of the subject. Referring to fig. 11, a part of light ray 50 emitted from projector 16 is reflected by cornea 75 to become reflected light ray 56. The reflected light 56 passes through the optical member 22, the optical member 21, the optical member 23, and the pseudo-eye optical system 24, and is incident on the detection surface 40a of the photodetector 40. Hereinafter, the reflected light ray 56 of the light ray 50 reflected by the cornea 75 is sometimes referred to as cornea reflected light ray 56, and the reflected light ray 51 of the light ray 50 reflected by the retina 74 is sometimes referred to as retina reflected light ray 51. Since the radius of curvature of the surface of the cornea 75 is about 7.8mm, the plurality of cornea-reflected light rays 56 substantially overlap the plurality of retina-reflected light rays 51. That is, the region where the plurality of cornea-reflected light rays 56 are incident on the detection surface 40a of the photodetector 40 substantially overlaps the region where the plurality of retina-reflected light rays 51 are incident on the detection surface 40a of the photodetector 40.

The amount of light of cornea-reflected light ray 56 is several tens of times larger than that of retina-reflected light ray 51. Therefore, when the cornea reflected light 56 is incident on the photodetector 40 in addition to the retina reflected light 51, a flare is generated in an image generated from an output signal of the photodetector 40, and it may be difficult to capture a fundus image of the retina 74.

Fig. 12 (a) is a diagram showing a trajectory of light reflected by the retina, and fig. 12 (b) is a diagram enlarging the vicinity of the pseudo-eye optical system of fig. 12 (a). Fig. 13 (a) is a diagram showing the trajectory of light reflected by the cornea, and fig. 13 (b) is a diagram enlarging the vicinity of the pseudo-eye optical system of fig. 13 (a). Fig. 14 (a) is a diagram showing only the optical axis of the light ray of fig. 13 (a), and fig. 14 (b) and 14 (c) are diagrams showing the trajectories of 2 light rays out of the 3 light rays of fig. 13 (a). Fig. 12 (a) to 14 (c) show a case where the fundus imaging apparatus is viewed from above, and show a case where the light ray 50 is irradiated only to one region 74a of the regions 74a and 74b obtained by dividing the retina 74 into two parts from the left and right with respect to the center of the retina 74. The direction in which the light ray 50 enters the center of the retina 74 is referred to as the Z direction, the horizontal direction is referred to as the X direction, and the vertical direction is referred to as the Y direction. The center of the retina 74 is set as the origin, the direction on the side of the region 74a with respect to the center (origin) of the retina 74 is set as the +x direction, and the direction on the side of the region 74b is set as the-X direction. In the whole fundus imaging apparatus, a region located on the +x side is defined as a +x region, and a region located on the-X side is defined as a-X region.

Referring to fig. 12 (a) and 12 (b), in the case where the light ray 50 is irradiated to the region 74a of the retina 74, the light ray 50 is incident on the eye 70 from the-X region. The retinal reflected light ray 51 reflected by the region 74a of the retina 74 returns to the optical component 21 along the trajectory substantially the same as the trajectory of the light ray 50 incident on the eye 70, and then is incident on the pseudo-eye optical system 24 through the optical component 21 and the optical component 23. That is, the retinal reflected light ray 51, after exiting from the eye 70 to the-X region, passes through the optical member 22 and the optical member 21, and is bent toward the +x region by the optical member 23 to be incident on the pseudo-eye optical system 24. Although not shown, when the light ray 50 irradiates the region 74b of the retina 74, the light ray 50 enters the eye 70 from the +x region. The retinal reflected light ray 51 reflected by the region 74b of the retina 74 returns to the optical component 21 along the trajectory substantially the same as the trajectory of the light ray 50 incident on the eye 70, and then is incident on the pseudo-eye optical system 24 through the optical component 21 and the optical component 23. That is, the retinal reflected light ray 51, after exiting from the eye 70 to the +x region, passes through the optical member 22 and the optical member 21, and is bent toward the-X region by the optical member 23 to be incident on the pseudo-eye optical system 24.

Referring to fig. 13 (a), 13 (b) and 14 (a), the cornea-reflected light 56, in which the light 50 irradiated to the region 74a of the retina 74 is reflected by the cornea 75, is reflected by the convex curved surface shape of the cornea 75 toward the +x region. After passing through the optical member 22 and the optical member 21, the cornea reflected light 56 is bent toward the-X region by the optical member 23 and enters the pseudo-eye optical system 24. Although not shown, when the light ray 50 irradiates the region 74b of the retina 74, the light ray 50 enters the eye 70 from the +x region, and the cornea-reflected light ray 56 reflected by the cornea 75 is reflected toward the-X region. After passing through the optical member 22 and the optical member 21, the cornea reflected light 56 is bent toward the +x region by the optical member 23 and enters the pseudo-eye optical system 24.

Referring to fig. 13 (a), 13 (b), 14 (b) and 14 (c), the cornea 75 has a convex curved shape, and thus the cornea reflected light 56 is reflected by the convex curved mirror. Since the light ray 50 is incident on the cornea 75 as substantially parallel light, the cornea-reflected light ray 56 reflected by the cornea 75 becomes diffuse light. The cornea-reflected light 56 is converted from diffuse light to substantially parallel light by the optical member 22, and then from substantially parallel light to converging light by the optical member 23. The cornea reflected light 56 is converted into converging light by the optical member 23 to be focused at a focus point 57 immediately in front of the pseudo-eye optical system 24. Since the pseudo-eye optical system 24 is disposed at the convergence point 53 located at a position substantially conjugate with the convergence point 52 at which the plurality of light rays 50 converge near the pupil 71 (the convergence point 52 and the convergence point 53 are the positions shown in fig. 2), the cornea-reflected light ray 56 is focused immediately in front of the pseudo-eye optical system 24. In other words, when the cornea-reflected light 56 is caused to extend into the eye 70, the cornea-reflected light 56 has a pair of focal points between the convergence point 52 and the cornea 75, the pair of focal points being in a substantially conjugate position with the pair of focal points 57.

As shown in fig. 12 (a) to 13 (b), in the case where the light ray 50 is irradiated to the region 74a of the retina 74, the retinal reflected light ray 51 and the cornea reflected light ray 56 travel on different paths to be incident on the pseudo-eye optical system 24. The same applies to the case where the light ray 50 irradiates the region 74b of the retina 74. Here, the virtual plane of the focal point 57 of the light ray 56 reflected by the cornea is set as a virtual plane 58. In the virtual plane 58, the retinal reflected light ray 51 is located approximately in the region of-X with respect to the X-axis origin, whereas the cornea reflected light ray 56 is located approximately in the region of +x with respect to the X-axis origin. Therefore, an example in which the influence of the cornea reflected light 56 on the fundus image is suppressed by using such a difference will be described below.

Fig. 15 is a block diagram of a fundus imaging apparatus of embodiment 6. Referring to fig. 15, fundus imaging apparatus 600 of embodiment 6 further includes drive control unit 34 and drive mechanism 95 as compared to fundus imaging apparatus 100 of embodiment 1 of fig. 1. When the image control unit 31 outputs a control signal for fundus imaging to the drive circuit 14, the drive control unit 34 outputs a control signal to the drive mechanism 95. The driving mechanism 95 drives a light shielding plate provided in the optical system 13 based on a control signal of the drive control unit 34 (see fig. 16 (a) to 16 (d), which will be described later). The driving mechanism 95 includes, for example, a stepping motor. Other structures are the same as those of fig. 1 of embodiment 1, and therefore, description thereof is omitted.

Fig. 16 (a) to 16 (d) are diagrams showing an optical system of the fundus imaging apparatus of embodiment 6. Fig. 16 (a) and 16 (b) illustrate the retinal reflected light ray 51 and the cornea reflected light ray 56 in the case where the light ray 50 is incident on the region 74a of the retina 74, and fig. 16 (c) and 16 (d) illustrate the retinal reflected light ray 51 and the cornea reflected light ray 56 in the case where the light ray 50 is incident on the region 74b of the retina 74. Fig. 16 (a) to 16 (d) show a case where the fundus imaging apparatus is viewed from above, and the illustration of the projector 16 is omitted for the sake of clarity of the drawings.

Referring to fig. 16 (a) to 16 (d), in fundus imaging apparatus 600 according to example 6, a light shielding plate 96 movable in the ±x direction as indicated by arrow 92 is disposed between optical member 23 and pseudo-eye optical system 24 at a position closer to pseudo-eye optical system 24 than the center between optical member 23 and pseudo-eye optical system 24. For example, the light shielding plate 96 is arranged on the virtual plane 58 of the focusing point 57 of the light ray 56 reflected by the cornea shown in fig. 12 (a) to 13 (b). The light shielding plate 96 is driven in the ±x directions of the arrow 92 by the driving mechanism 95. Other structures are the same as those of embodiment 1, and therefore, description thereof is omitted.

Referring to fig. 16 (a) and 16 (b), when light ray 50 is incident on region 74a of retina 74, light shielding plate 96 is moved to a first position where all of the plurality of cornea-reflected light rays 56 are shielded and a part of each of the plurality of retina-reflected light rays 51 is passed. Here, as shown in fig. 12 (a) to 13 (b), in the virtual plane 58, the plurality of cornea-reflected light rays 56 are focused, whereas the plurality of retina-reflected light rays 51 are substantially converged, and the plurality of retina-reflected light rays 51 are substantially parallel light rays having substantially the same size as when the light rays 50 are incident on the cornea 75, respectively. The diameter of the retinal reflected light ray 51 on the virtual plane 58 is about 0.8mm to 1.65 mm. When all of the plurality of cornea reflected lights 56 are blocked by the light shielding plate 96, the tip of the light shielding plate 96 slightly flies out from the origin of the X axis toward the-X region. Therefore, the retinal reflected light ray 51 is formed into a half-divided shape by the light shielding plate 96.

Fig. 17 is a diagram showing an example of a retinal reflected light ray having a half-divided shape. Since the diameter of the retinal reflected light ray 51 on the virtual plane 58 is about 0.8mm to 1.65mm and the protruding amount of the light shielding plate 96 from the origin to the-X region is about 10 μm to 50 μm, no problem occurs in the detection of the photodetector 40 even if the retinal reflected light ray 51 is formed into a half-divided shape by the light shielding plate 96. Accordingly, the plurality of cornea-reflected light rays 56 reflected by the cornea 75 are blocked by the light blocking plate 96 to suppress incidence to the photodetector 40, and a part of each of the plurality of retina-reflected light rays 51 reflected by the region 74a of the retina 74 is detected by the photodetector 40 through the light blocking plate 96.

As shown in fig. 16 (c) and 16 (d), when the light ray 50 is incident on the region 74b of the retina 74, the light shielding plate 96 is moved to the second position where all of the plurality of cornea-reflected light rays 56 are shielded and a part of each of the plurality of retina-reflected light rays 51 is passed. Thus, the plurality of cornea-reflected light rays 56 reflected by the cornea 75 are blocked by the light shielding plate 96 to suppress incidence to the photodetector 40, and a part of each of the plurality of retina-reflected light rays 51 reflected by the region 74b of the retina 74 is detected by the photodetector 40 through the light shielding plate 96.

Fig. 18 is a flowchart showing an example of fundus imaging processing. Referring to fig. 18, the drive control unit 34 controls the driving of the driving mechanism 95 to move the light shielding plate 96 to the first position shown in fig. 16 a and 16 b (step S30). Next, the image control unit 31 controls the driving of the light source 11 and the scanning unit 12, and emits the light beam 50 for fundus imaging from the projector 16, and irradiates only the region 74a out of the regions 74a and 74b obtained by dividing the retina 74 into two parts (step S32). Here, the light beam 50 is irradiated only to the region 74a, and for example, in the scanning of the light beam 50 on the retina 74 described with reference to fig. 4, the light beam 50 may be emitted from the light source 11 only when the scanning unit 12 scans the region 74 a. As a result, as shown in fig. 16 (a) and 16 (b), a part of each of the plurality of retinal reflected lights 51 reflected by the region 74a of the retina 74 is incident on the photodetector 40 and detected, but all of the plurality of cornea reflected lights 56 reflected by the cornea 75 are blocked by the light blocking plate 96, and incidence to the photodetector 40 is suppressed. The order of step S30 and step S32 may be reversed.

Next, the signal processing unit 32 acquires an output signal of the photodetector 40 (step S34). Next, the image generating unit 33 generates a first image relating to the fundus based on the result of processing the output signal of the photodetector 40 by the signal processing unit 32 (step S36). The first image is a fundus image associated with the region 74a of the retina 74.

Next, the drive control unit 34 controls the driving of the driving mechanism 95 to move the light shielding plate 96 to the second position shown in fig. 16 (c) and 16 (d) (step S38). Next, the image control unit 31 controls the driving of the light source 11 and the scanning unit 12, and emits the light beam 50 for fundus imaging from the projector 16, and irradiates only the region 74b out of the regions 74a and 74b of the retina 74 (step S40). The light 50 may be emitted from the light source 11 only when the scanning unit 12 scans the region 74b, as in the case of the light 50 being emitted only to the region 74 b. As a result, as shown in fig. 16 (c) and 16 (d), a part of each of the plurality of retinal reflected lights 51 reflected by the region 74b of the retina 74 is incident on the photodetector 40 and detected, but all of the plurality of cornea reflected lights 56 reflected by the cornea 75 are blocked by the light blocking plate 96, and incidence to the photodetector 40 is suppressed. The order of step S38 and step S40 may be reversed.

Next, the signal processing unit 32 acquires an output signal of the photodetector 40 (step S42). Next, the image generating unit 33 generates a second image relating to the fundus based on the result of processing the output signal of the photodetector 40 by the signal processing unit 32 (step S44). The second image is a fundus image associated with the region 74b of the retina 74.

Next, the image generating unit 33 synthesizes the first image generated in step S36 and the second image generated in step S44, and generates a fundus image of the entire retina 74 (step S46). The display section 41 displays the fundus image generated by the image generating section 33 (step S48).

According to example 6, as shown in fig. 16 (a) to 16 (d), the image control unit 31 (irradiation region adjustment unit) does not irradiate the region 74b when the light ray 50 is irradiated to the region 74a out of the two regions 74a and 74b divided into two parts about the retina 74, and does not irradiate the region 74a when the region 74b is irradiated. The light shielding plate 96 (light shielding member) is movably disposed between the optical member 23 and the pseudo-eye optical system 24. In other words, the light shielding plate 96 is movably disposed between the optical member 23 and the convergence point 53. The light shielding plate 96 is moved by a driving mechanism 95 (see fig. 15). As shown in fig. 16 (a) and 16 (b), when the light 50 irradiates only the region 74a, the drive mechanism 95 moves the light shielding plate 96 to the first position where the cornea-reflected light 56 is shielded and the retina-reflected light 51 passes through. As shown in fig. 16 (c) and 16 (d), when the light ray 50 is irradiated only to the region 74b, the light shielding plate 96 is moved to the second position where the cornea-reflected light ray 56 is shielded and the retina-reflected light ray 51 is passed. Then, when the light ray 50 is irradiated to each of the regions 74a and 74b, the image generating unit 33 generates an image based on the output signal of the photodetector 40, and synthesizes the two images to generate a fundus image. This suppresses the influence of the cornea reflection light 56 on the fundus image, and a favorable fundus image can be obtained. In example 6, the case where the retina 74 is divided into two parts in the left and right is exemplified, but the present invention is not limited to this case, and other cases may be used as long as the retina 74 is divided into two parts with respect to the center of the retina 74, such as the case where the retina 74 is divided into two parts in the up and down directions.

In embodiment 6, the case where the image control unit 31 performs the function of an irradiation region adjustment unit that does not irradiate the region 74b when the light 50 is irradiated to the region 74a, and does not irradiate the region 74a when the light 50 is irradiated to the region 74b, is described as an example, but the present invention is not limited to this case. Fig. 19 (a) and 19 (b) are diagrams showing an optical system of the fundus imaging apparatus according to modification 1 of embodiment 6. Referring to fig. 19 (a) and 19 (b), a light shielding plate 97 disposed between the optical member 21 and the optical member 22 so as to be movable in the ±x directions may function as the irradiation region adjustment section. That is, the light beam 50 may be irradiated only to the region 74a by moving the light shielding plate 97 to the first position, and the light beam 50 may be irradiated only to the region 74b by moving the light shielding plate 97 to the second position. The light shielding plate 97 may be driven by the driving mechanism 95. The light shielding plate 97 is not limited to the case of being disposed between the optical member 21 and the optical member 22, and may be disposed between the optical member 19 and the optical member 21 or between the optical member 22 and the eye 70.

The radii of curvature of the surfaces of the cornea 75 are subject to individual differences, and are distributed to the extent of 7.8 mm.+ -. 1.0 mm. When the radius of curvature of the cornea 75 is different, the position of the focal point 57 of the cornea reflected light 56 changes. Fig. 20 (a) to 20 (c) are diagrams showing a change in the position of the focal point of the reflected light of the cornea due to a difference in the radius of curvature of the cornea. In fig. 20 (b) and 20 (c), a virtual plane 58 in fig. 20 (a) is illustrated with a broken line. Fig. 20 (a) shows a case where the radius of curvature of the cornea 75 is 7.8 mm. When the radius of curvature is smaller than 7.8mm, as shown in fig. 20 (b), the focal point 57 of the cornea-reflected light ray 56, i.e., the virtual plane 58 approaches the pseudo-eye optical system 24. In contrast, when the radius of curvature is greater than 7.8mm, as shown in fig. 20 (c), the focal point 57 of the cornea-reflected light ray 56, i.e., the virtual plane 58, is away from the pseudo-eye optical system 24. For example, in the case where the radius of curvature is 6.8mm, the position of the focusing point 57 (the position of the virtual plane 58) is approximately 0.5mm as compared with the case where the radius of curvature is 7.8 mm. In the case of the radius of curvature of 8.8mm, the position of the focusing point 57 (the position of the virtual plane 58) is separated by about 0.5mm from the pseudo-eye optical system 24, compared with the case of the radius of curvature of 7.8 mm.

When the light shielding plate 96 is arranged offset from the virtual plane 58, the larger the offset amount is, the larger the beam diameter of the light ray 56 is reflected at the cornea of the light shielding plate 96. That is, as shown in fig. 16 (b) and 16 (d), when the cornea-reflected light ray 56 is shielded by the shielding plate 96, the protruding amount of the tip of the shielding plate 96 to the-X region or the +x region becomes large, and as a result, the beam diameter of the retina-reflected light ray 51 passing through the shielding plate 96 becomes small. Therefore, the light shielding plate 96 is preferably disposed on the virtual plane 58 or near the virtual plane 58. That is, the light shielding plate 96 is preferably disposed at or near the focusing point 57 at which the cornea-reflected light ray 56 is focused in front of the pseudo-eye optical system 24 (i.e., in front of the convergence point 53). The vicinity of the focusing point 57 refers to a case where, for example, it is within a range from the focusing point 57 to a distance between the focusing point 57 and the convergence point 53.

As shown in fig. 20 (a) to 20 (c), the position of the focusing point 57 of the cornea reflected light 56 varies according to the radius of curvature of the cornea 75, and therefore, it is preferable that the driving mechanism 95 be capable of moving not only the light shielding plate 96 in the ±x direction but also in the ±z direction. In other words, the light shielding plate 96 is preferably movable in a first direction in which the cornea-reflected light 56 is incident on the light shielding plate 96 and in a second direction intersecting the first direction. The driving mechanism 95 may drive the light shielding plate 96 and the pseudo-eye optical system 24 integrally in the ±z directions.

In embodiment 6, the case where the two-dimensional scanned light ray 50 is emitted from the projector 16 is illustrated, but the case where the light not two-dimensional scanned (photographing light for fundus photographing) is emitted may be also exemplified. In this case, by using an optical system including the optical member 19, the optical member 21, the optical member 22, the optical member 23, and the light shielding plate 96, the influence of the reflected light of the photographing light reflected by the cornea 75 on the fundus image can be suppressed, and a good fundus image can be obtained. In the case of emitting the photographing light which is not two-dimensionally scanned, the optical system may not be provided with the pseudo-eye optical system 24.

Fig. 21 is a side view showing an example of a case where a light shielding plate disposed on a virtual plane has a コ -shaped form. In fig. 21, the retinal reflected light ray 51 and the cornea reflected light ray 56 reflected by the retina 74 and the cornea 75 at different times are illustrated, and the cornea reflected light ray 56 is hatched for clarity of the drawing (the same applies to fig. 22 (a) and 22 (b) described later). As shown in fig. 21, regarding the size of the cornea-reflected light 56 disposed at the light shielding plate 96a of the virtual plane 58, the cornea-reflected light 56 located at the center is smallest, and gradually expands as it goes away from the center due to the influence of the aberration of the optical system. In order to block the enlarged cornea reflection light 56, the peripheral side of the light shielding plate 96a is preferably widened.

Fig. 22 (a) and 22 (b) are diagrams showing problems that occur when a flat light shielding plate is used to shield a cornea reflected light beam. As shown in fig. 22 (a), if a flat-type light shielding plate 96 is disposed at a position where the cornea-reflected light 56 located at the central portion is blocked, there is a case where the expanded cornea-reflected light 56 located at a position distant from the central portion cannot be blocked. As shown in fig. 22 (b), when the light shielding plate 96 is increased so as to be able to shield the enlarged cornea reflected light beam 56, the shielding of the retina reflected light beam 51 is increased, and the light of the fundus image is attenuated.

As shown in fig. 21, by using the コ -shaped light shielding plate 96a having a concave shape at the central portion corresponding to the cornea reflected light ray 56 and protruding away from the peripheral portion of the central portion, the peripheral, enlarged cornea reflected light ray 56 can be shielded, and the dimming of the retina reflected light ray 51 can be suppressed to be small. The movement of the light shielding plate 96a from the first position to the second position described in fig. 16 (a) to 16 (d) can be performed by rotating the light shielding plate 96a by 180 ° by the driving mechanism 95.

In the fundus imaging apparatuses according to embodiments 1 to 6, the simulated eye optical system 24 and the photodetector 40 have the same functions as those of a general digital camera when the simulated eye optical system 24 is a camera lens and the photodetector 40 is an imaging sensor, and therefore the simulated eye optical system 24, the photodetector 40, and the image generation unit 33 can be replaced with a digital camera. Here, in the case of replacing the camera with a digital camera in embodiment 6, attention is sometimes paid to the positional relationship between the camera lens and the light shielding plate 96 or 96 a. That is, in order to improve the optical characteristics of the camera lens, the focusing point 57 of the optical system of the fundus imaging apparatus of example 6 may be positioned inside the camera lens by combining a plurality of lenses or the like. In this case, the camera lens interferes with the light shielding plate 96 or 96 a. On the other hand, the focusing point 57 of the camera lens used in a smart phone or the like is often on the outer side of the camera lens, and it is preferable to use such a camera lens in the fundus imaging apparatus of embodiment 6 while downsizing. Further, as described in embodiment 1, if the projector 16 is a general-purpose projector, a digital camera and a general-purpose projector may be used to construct the fundus imaging apparatus.

Example 7

In example 6, a structure and a method for reducing the influence of the cornea reflected light 56 are described. In this embodiment 7, a different structure and method for reducing the influence of the cornea reflected light 56 are described.

Fig. 23 is a diagram showing an optical system of a fundus imaging apparatus 700 of embodiment 7. Referring to fig. 23, in fundus imaging apparatus 700, polarizing plate 81 and optical member 21b are disposed on the optical paths of a plurality of light rays 50 emitted from projector 16. The polarizing plate 81 may be provided between the attenuation filter 20 and the optical member 21b, or may be provided between the attenuation filter 20 and the optical member 19.

In the case where the projector 16 is a laser scanning projector, the emitted light 50 is a linearly polarized laser. The polarizing plate 81 is a polarizing filter that adjusts the light beam 50 of the linearly polarized light so as to transmit the S wave corresponding to the optical characteristics of the optical member 21b. The polarizing plate 81 converts the light beam 50 of the linearly polarized light emitted from the projector 16 into an S wave that vibrates perpendicular to a plane including the normal line of the reflection surface of the optical member 21b and the incident light beam, and makes the S wave incident on the optical member 21b. The optical member 21b is a polarizing beam splitter that reflects S-waves and transmits waves other than S-waves, and reflects the light beam 50 of S-waves transmitted through the polarizing plate 81. In order to efficiently reflect the S-wave by the optical member 21b, the optical characteristics of the polarizer 81 and the optical member 21b are adjusted by including the orientation and/or positional relationship thereof.

The S-wave ray 50 passes through the optical member 22 and irradiates the cornea 75 and the retina 74. The cornea 75 transmits most of the irradiated light ray 50 and reflects a part thereof, but since the cornea 75 is a substantially uniform spherical surface, the irradiated light ray 50 of the S wave is reflected while maintaining the state of the S wave. Since the surface of the retina 74 has fine projections and depressions, the light ray 50 of the S wave irradiated to the retina 74 is not reflected as a certain polarized light but as a random polarized light.

The reflected light of the S wave reflected by the cornea 75 and the reflected light of the randomly polarized light reflected by the retina 74 pass through the optical component 22. The reflected light of the S wave reflected by the cornea 75 is reflected by the optical member 21b, does not pass through the optical member 21b, and therefore does not reach the photodetector 40. On the other hand, the reflected light ray 51 other than the S wave of the randomly polarized light reflected by the retina 74 passes through the optical member 21b and reaches the photodetector 40. Thus, the reflected light beam 51 other than the S wave of the randomly polarized light reflected by the retina 74 is detected by the photodetector 40 without being detected by the photodetector 40, and therefore, the influence of the component of the light reflected by the cornea 75 can be reduced, and the reflected light beam 51 reflected by the retina 74 is detected mainly by the photodetector 40, so that the S/N of the fundus image can be improved.

Here, the same effect can be obtained by the same operation as described above, by using the polarizing plate 81 as a polarizing filter that is adjusted so as to transmit the P-wave of the light beam 50 of the linearly polarized light, and using the optical member 21b as a polarizing beam splitter that reflects the P-wave transmitted through the polarizing plate 81 and transmits the other P-wave. The projector 16 is a laser scanning projector that outputs laser light as linearly polarized light, but in the case of using a projector that emits unpolarized light based on illumination light without using laser scanning, it is also possible to use the projector by adjusting the optical characteristics of the polarizing plate 81 and the optical member 21b so as to correspond to the unpolarized light. For example, when the projector 16 emits light having no polarization, the polarizing plate 81 may transmit light having no polarization as light having perpendicular polarization.

In the fundus imaging apparatuses according to embodiments 1 to 7, in addition to imaging the fundus, it is possible to perform visual function inspection by emitting light from the projector 16 after two-dimensional scanning for projecting an inspection target for inspecting visual functions (for example, a visual field). Thus, both acquisition of fundus images and visual function inspection can be performed using 1 projector 16.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the specific embodiments, and various modifications and alterations are possible within the scope of the present invention described in the claims.

Claims (35)

1. A fundus imaging apparatus includes:

a light source which emits light;

a scanning part for performing two-dimensional scanning on the light, and

A first optical member that irradiates a retina of a subject after converging a plurality of light rays, which are scanned by the scanning unit and are emitted at different times, at a first convergence point near the pupil of the subject;

A second optical member that condenses a plurality of first reflected light rays, which are reflected by the retina of the subject and transmitted through the first optical member, at a second convergence point;

an optical system disposed at the second convergence point and converting the plurality of first reflected light rays into converged light, respectively;

a photodetector for detecting the first reflected light rays transmitted through the optical system, and

And an image generation unit that generates a fundus image based on the output signal of the photodetector.

2. The fundus imaging apparatus according to claim 1, wherein,

The first convergence point and the second convergence point are located at conjugated positions,

The retina of the subject is located at a conjugate position to the photodetector.

3. The fundus imaging apparatus according to claim 1, wherein,

The scanning unit and the first convergence point are in a conjugate positional relationship.

4. The fundus imaging apparatus according to claim 1, wherein,

The first optical member converges the plurality of light rays at the first convergence point and converts the plurality of light rays from diffused light to parallel light, respectively,

The second optical component converges the plurality of first reflected light rays at the second convergence point and converts the plurality of first reflected light rays from diffused light to parallel light, respectively,

The optical system converts the plurality of first reflected light rays from parallel light to converging light, respectively.

5. The fundus imaging apparatus according to claim 1, wherein,

The plurality of first reflected light rays are focused before the second optical member, become diffused light, and are incident on the second optical member.

6. The fundus imaging apparatus according to claim 1, wherein,

The beam diameter of the light beam incident on the cornea of the subject is 0.8mm or more and 1.65mm or less.

7. The fundus imaging apparatus according to claim 1, wherein,

The fundus imaging apparatus includes a third optical member disposed between the first optical member and the second optical member,

A plurality of the light rays are reflected by the third optical member to be incident on the first optical member,

The plurality of first reflected light rays reflected by the retina of the subject are transmitted through the first optical member and the third optical member and are incident on the second optical member.

8. The fundus imaging apparatus according to claim 7, wherein,

The fundus imaging apparatus includes a 1/4 wavelength plate, the 1/4 wavelength plate being disposed between the third optical member and the first optical member,

The third optical component is a polarizing beam splitter.

9. The fundus imaging apparatus according to claim 1, wherein,

The fundus imaging apparatus includes:

a light source for emitting a backlight irradiated to the retina of the subject, and

A fourth optical member disposed between the first optical member and the second optical member,

The background light emitted from the light source is reflected by the fourth optical member, and transmitted through the first optical member to be irradiated to the retina of the subject.

10. The fundus imaging apparatus according to claim 1, wherein,

The fundus imaging apparatus includes a fifth optical member that is disposed between the second optical member and the optical system and bends the plurality of first reflected light rays.

11. The fundus imaging apparatus according to claim 1, wherein,

The focal length of the first optical component is different from the focal length of the second optical component.

12. The fundus imaging apparatus according to claim 1, wherein,

The fundus imaging apparatus includes:

A light shielding member movably disposed between the second optical member and the second convergence point, and

And a driving mechanism that moves the light shielding member to a first position at which a second reflected light beam transmitted through the first optical member and the second optical member by reflection of the light beam by the cornea of the subject is shielded and the first reflected light beam passes.

13. The fundus imaging apparatus according to claim 1, wherein,

The fundus imaging apparatus includes:

An irradiation region adjustment unit that does not irradiate the first region and does not irradiate the second region with the light when the first region and the second region are divided into two parts with respect to the center of the retina of the subject are irradiated with the light, and does not irradiate the first region with the light when the second region is irradiated with the light;

A light shielding member movably disposed between the second optical member and the second convergence point, and

A driving mechanism that moves the light shielding member to a first position at which a second reflected light beam that has passed through the first optical member and the second optical member by being reflected by the cornea of the subject passes through the first optical member when the light beam is irradiated only to the first region, and moves the light shielding member to a second position at which the second reflected light beam is blocked and the first reflected light beam passes when the light beam is irradiated only to the second region,

The image generation unit generates an image based on an output signal of the photodetector when the light is irradiated to the first region or the second region, and synthesizes the two generated images to generate the fundus image.

14. The fundus imaging apparatus according to claim 12, wherein,

The light shielding member is disposed at or near a focal point at which the second reflected light is focused in front of the second convergence point.

15. The fundus imaging apparatus according to claim 12, wherein,

The light shielding member is movable in a first direction in which the second reflected light is incident on the light shielding member and a second direction intersecting the first direction.

16. The fundus imaging apparatus according to claim 12, wherein,

The shading component is コ -shaped, wherein the central part of the second reflected light is concave.

17. The fundus imaging apparatus according to claim 1, wherein,

The optical system, the photodetector, and the image generating unit are digital cameras.

18. A fundus imaging apparatus includes a projector, a projection unit, and an image generation unit,

The projector is provided with:

a light source which emits light;

a scanning part for performing two-dimensional scanning on the light, and

An emitting unit which emits the scanned light beam,

The projection unit includes:

a first optical member that irradiates a retina of a subject after converging a plurality of the light rays emitted from the projector at different times at a first convergence point near the pupil of the subject;

A second optical member that condenses a plurality of first reflected light rays, which are reflected by the retina of the subject and transmitted through the first optical member, at a second convergence point;

An optical system disposed at the second convergence point and converting the first reflected light beams into converged light, respectively, and

A photodetector that detects the plurality of first reflected lights transmitted through the optical system,

The image generation unit generates a fundus image from an output signal of the photodetector.

19. The fundus imaging apparatus according to claim 18, wherein,

The first convergence point and the second convergence point are located at conjugated positions,

The retina of the subject is located at a conjugate position to the photodetector.

20. The fundus imaging apparatus according to claim 18, wherein,

The scanning unit and the first convergence point are in a conjugate positional relationship.

21. The fundus imaging apparatus according to claim 18, wherein,

The first optical member converges the plurality of light rays at the first convergence point and converts the plurality of light rays from diffused light to parallel light, respectively,

The second optical component converges the plurality of first reflected light rays at the second convergence point and converts the plurality of first reflected light rays from diffused light to parallel light, respectively,

The optical system converts the plurality of first reflected light rays from parallel light to converging light, respectively.

22. The fundus imaging apparatus according to claim 18, wherein,

The plurality of first reflected light rays are focused before the second optical member, become diffused light, and are incident on the second optical member.

23. The fundus imaging apparatus according to claim 18, wherein,

The beam diameter of the light beam incident on the cornea of the subject is 0.8mm or more and 1.65mm or less.

24. The fundus imaging apparatus according to claim 18, wherein,

The fundus imaging apparatus includes a third optical member disposed between the first optical member and the second optical member,

A plurality of the light rays are reflected by the third optical member to be incident on the first optical member,

The plurality of first reflected light rays reflected by the retina of the subject are transmitted through the first optical member and the third optical member and are incident on the second optical member.

25. The fundus imaging apparatus according to claim 24, wherein,

The fundus imaging apparatus includes a 1/4 wavelength plate, the 1/4 wavelength plate being disposed between the third optical member and the first optical member,

The third optical component is a polarizing beam splitter.

26. The fundus imaging apparatus according to claim 18, wherein,

The fundus imaging apparatus includes:

a light source for emitting a backlight irradiated to the retina of the subject, and

A fourth optical member disposed between the first optical member and the second optical member,

The background light emitted from the light source is reflected by the fourth optical member, and transmitted through the first optical member to be irradiated to the retina of the subject.

27. The fundus imaging apparatus according to claim 18, wherein,

The fundus imaging apparatus includes a fifth optical member that is disposed between the second optical member and the optical system and bends the plurality of first reflected light rays.

28. The fundus imaging apparatus according to claim 18, wherein,

The focal length of the first optical component is different from the focal length of the second optical component.

29. The fundus imaging apparatus according to claim 18, wherein,

The fundus imaging apparatus includes:

A light shielding member movably disposed between the second optical member and the second convergence point, and

And a driving mechanism that moves the light shielding member to a first position at which a second reflected light beam transmitted through the first optical member and the second optical member by reflection of the light beam by the cornea of the subject is shielded and the first reflected light beam passes.

30. The fundus imaging apparatus according to claim 18, wherein,

The fundus imaging apparatus includes:

An irradiation region adjustment unit that does not irradiate the first region and does not irradiate the second region with the light when the first region and the second region are divided into two parts with respect to the center of the retina of the subject are irradiated with the light, and does not irradiate the first region with the light when the second region is irradiated with the light;

A light shielding member movably disposed between the second optical member and the second convergence point, and

A driving mechanism that moves the light shielding member to a first position at which a second reflected light beam that has passed through the first optical member and the second optical member by being reflected by the cornea of the subject passes through the first optical member when the light beam is irradiated only to the first region, and moves the light shielding member to a second position at which the second reflected light beam is blocked and the first reflected light beam passes when the light beam is irradiated only to the second region,

The image generation unit generates an image based on an output signal of the photodetector when the light is irradiated to the first region or the second region, and synthesizes the two generated images to generate the fundus image.

31. The fundus imaging apparatus according to claim 29, wherein,

The light shielding member is disposed at or near a focal point at which the second reflected light is focused in front of the second convergence point.

32. The fundus imaging apparatus according to claim 29, wherein,

The light shielding member is movable in a first direction in which the second reflected light is incident on the light shielding member and a second direction intersecting the first direction.

33. The fundus imaging apparatus according to claim 29, wherein,

The shading component is コ -shaped, wherein the central part of the second reflected light is concave.

34. The fundus imaging apparatus according to claim 18, wherein,

The optical system, the photodetector, and the image generating unit are digital cameras.

35. The fundus imaging apparatus according to claim 18, wherein,

The projector is a removable universal projector.