Fundus imaging device, method for controlling fundus imaging device, and program

Abstract

A fundus imaging device includes two or more curved mirrors, an illumination optical system, an image sensor, and a control unit. The illumination optical system irradiates slit-shaped illumination light to the fundus of an eye to be examined by means of two or more curved mirrors, and illuminates the fundus while moving an illumination region. The image sensor can be disposed at a fundus conjugate position substantially optically conjugate to the fundus, and receives return light from the subject eye. The control unit controls at least the illumination optical system. The longitudinal direction of an image formed by the illumination light at the fundus is substantially parallel to a plane including two or more focal points of the two or more curved mirrors. The control unit controls the illumination optical system so that the image moves in a direction intersecting the longitudinal direction at the fundus.

Description

Technical Field

[0001] The present invention relates to a fundus photographing device, a control method and a program for the fundus photographing device. Background Art

[0002] For fundus photographing devices (fundus photographing devices) used for screening and treatment of eye diseases, it is required to be able to easily photograph (observe) the fundus of the eye under examination with a wide field of view. Specifically, it is required to photograph the fundus of the eye under examination with a wide angle of view exceeding 80 degrees in one shot. A scanning laser ophthalmoscope (SLO) is known as such a fundus photographing device. SLO is a device that forms a fundus image by scanning the fundus with light and detecting its return light with a photosensitive device.

[0003] For example, Patent Document 1 discloses a scanning ophthalmoscope that can scan the retina at a wide angle by moving two-dimensional parallel light scanning using a polygon mirror and a plane mirror to a subject's eye via a scanning moving unit.

[0004] For example, Patent Documents 2 and 3 disclose fundus imaging devices that can acquire high-contrast images with a simple structure by combining fundus scanning using slit-shaped illumination light and a rolling shutter. In particular, Patent Document 3 discloses a method for acquiring a wide-angle fundus image of the eye under examination by scanning the fundus of the eye under examination using slit-shaped illumination light with the aid of two elliptical concave mirrors.

[0005] Patent Document 1: Japanese Patent Application No. 2009-543585

[0006] Patent Document 2: U.S. Patent No. 7831106

[0007] Patent Document 3: International Publication No. 2022 / 124170 Summary of the invention

[0008] The method disclosed in Patent Document 1 requires a high-speed scanner such as a polygon mirror, but a high-speed scanner capable of scanning at a wide angle is very expensive.

[0009] In addition, when photographing the fundus at a wide angle, it is preferred to spatially separate the optical path of the return light from the optical path of the illumination light at a branch point at a position conjugate with the pupil of the eye to be examined. In the method disclosed in Patent Document 2, not only is pupil division difficult, but it is also very difficult to keep the light beam for illuminating a wide range of the fundus and the light beam of the return light within the optical effective diameter while maintaining the working distance.

[0010] Furthermore, the method disclosed in Patent Document 3 can capture the fundus of the eye to be examined at a wide angle at low cost and with a simple structure, but is easily affected by ellipsoidal aberration and requires a high level of optical design.

[0011] Such a problem is common not only in the case of acquiring a wide-angle image of the fundus, but also in the case of acquiring a fundus image.

[0012] The present invention has been made in view of the above circumstances, and one of its objects is to provide a new technology for acquiring a higher-quality fundus image of a subject's eye with a low cost and a simple structure without requiring a high-level optical design.

[0013] One embodiment provides a fundus photographing device, comprising: two or more curved mirrors; an illumination optical system, which uses the two or more curved mirrors to irradiate a slit-shaped illumination light onto the fundus of an eye to be examined, illuminating the fundus while moving the illumination area; an image sensor that can be arranged at a fundus conjugate position that is approximately optically conjugate with the fundus, and receives return light from the eye to be examined; and a control unit, which controls at least the illumination optical system, so that the length direction of an image formed by the illumination light at the fundus is approximately parallel to a plane including two or more focal points of the two or more curved mirrors, and the control unit controls the illumination optical system in such a manner that the image moves at the fundus in a direction intersecting the length direction.

[0014] Another embodiment provides a control method for a fundus photographing device, the fundus photographing device comprising: two or more curved mirrors; an illumination optical system, which illuminates the fundus of an eye to be examined by means of the two or more curved mirrors, and illuminates the fundus while moving the illumination area; and an image sensor, which can be arranged at a fundus conjugate position that is substantially optically conjugate with the fundus, and receives return light from the eye to be examined, wherein the length direction of an image formed by the illumination light at the fundus is substantially parallel to a plane including two or more focal points of the two or more curved mirrors. The control method for the fundus photographing device comprises: a control step of controlling the illumination optical system so that the image moves at the fundus in a direction intersecting the length direction; and an introduction step of introducing the light reception result of the return light in the light receiving area of ​​the light receiving surface of the image sensor corresponding to the position of the image at the fundus.

[0015] Still another aspect of the embodiment is a program that causes a computer to execute each step of the control method of the fundus imaging device described above.

[0016] According to the present invention, it is possible to provide a new technology for acquiring a higher-quality fundus image of a subject's eye at low cost and with a simple structure without requiring a high-level optical design. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram showing an example of the configuration of an optical system of the fundus imaging device according to the embodiment.

[0018] Figure 2 It is a schematic diagram showing an example of the configuration of an optical system of the fundus imaging device according to the embodiment.

[0019] Figure 3 It is a schematic diagram showing an example of the configuration of an optical system of the fundus imaging device according to the embodiment.

[0020] Figure 4 This is a schematic diagram for explaining the configuration of an optical system of a fundus imaging device according to an embodiment.

[0021] Figure 5 It is a schematic diagram showing an example of the configuration of an optical system of the fundus imaging device according to the embodiment.

[0022] Figure 6 It is a schematic diagram showing an example of the configuration of an optical system of the fundus imaging device according to the embodiment.

[0023] Figure 7 It is a schematic diagram showing an example of the configuration of an optical system of the fundus imaging device according to the embodiment.

[0024] Figure 8 It is a schematic diagram showing an example of the configuration of an optical system of the fundus imaging device according to the embodiment.

[0025] Fig. 9A This is a schematic diagram for explaining the operation of the fundus imaging device according to the embodiment.

[0026] Fig. 9B This is a schematic diagram for explaining the operation of the fundus imaging device according to the embodiment.

[0027] Fig. 9C This is a schematic diagram for explaining the operation of the fundus imaging device according to the embodiment.

[0028] Fig. 10A This is a schematic diagram for explaining the operation of a fundus imaging device according to a comparative example of the embodiment.

[0029] Fig. 10B This is a schematic diagram for explaining the operation of the fundus imaging device according to the embodiment.

[0030] Fig.11 1 is a schematic diagram showing an example of the configuration of a processing system of the fundus imaging device according to the embodiment.

[0031] Fig.121 is a flowchart showing an operation example of the fundus imaging device according to the embodiment.

[0032] Fig.13 It is a schematic diagram showing an example of the configuration of an optical system of a fundus imaging device according to a first modified example of the embodiment.

[0033] Fig.14 It is a schematic diagram showing an example of the configuration of an optical system of a fundus imaging device according to a first modified example of the embodiment.

[0034] Fig.15 1 is a schematic diagram showing an example of the configuration of a processing system of a fundus imaging device according to a first modified example of the embodiment.

[0035] Fig.16 1 is a flowchart showing an operation example of the fundus imaging device according to the first modified example of the embodiment.

[0036] Fig.17 It is a schematic diagram showing an example of the configuration of an optical system of a fundus imaging device according to a second modified example of the embodiment. DETAILED DESCRIPTION

[0037] The fundus imaging device, the control method of the fundus imaging device, and the program according to the present invention will be described in detail with reference to the accompanying drawings. In addition, the contents of the documents cited in this specification or any known technology may be cited in the following embodiments.

[0038] The fundus photographing device of the embodiment is configured to include two or more curved mirrors, and the fundus of the inspected eye is scanned with slit-shaped illumination light by means of the two or more curved mirrors, and the return light from the inspected eye is received by an image sensor. Each curved mirror has one or more focal points. The two or more curved mirrors are configured so that the two or more focal points of the two or more curved mirrors are configured on approximately the same plane (common plane of focal points). The fundus photographing device illuminates the fundus with illumination light in a manner such that the length direction of the slit image projected onto the fundus and formed by the illumination light is approximately parallel to the plane including the two or more focal points, and scans the fundus with illumination light in a direction intersecting with the length direction (specifically, an orthogonal direction).

[0039] Examples of curved mirrors include elliptical mirrors, parabolic mirrors, hyperbolic mirrors, free-form mirrors, and mirrors whose reflection surfaces are represented by high-order polynomials. The reflection surface of the curved mirror may be a concave reflection surface or a concave reflection surface. That is, examples of curved mirrors include elliptical concave mirrors, elliptical convex mirrors, parabolic concave mirrors, parabolic convex mirrors, hyperbolic concave mirrors, hyperbolic convex mirrors, free-form mirrors with concave reflection surfaces, free-form mirrors with convex reflection surfaces, concave mirrors with reflection surfaces represented by high-order polynomials, and convex mirrors with reflection surfaces represented by high-order polynomials.

[0040] In this specification, the focus includes not only a fixed point uniquely determined by the shape of a curved surface, but also a position where the concentration of light (light beam) reflected by a reflecting surface is higher than that of other positions.

[0041] Preferably, the focus-sharing plane is a plane on which all the foci of the two or more curved mirrors are arranged. However, the focus-sharing plane may also be a plane on which two or more foci of all the foci of the two or more curved mirrors except at least one are arranged.

[0042] The slit image projected onto the fundus is, for example, a rectangular image. However, the shape of the slit image may be a quadrilateral shape such as a parallelogram or a trapezoid, a polygonal shape, or a shape extending in the length direction along one or more predetermined straight lines or curves with a predetermined slit width (the slit width may not be constant). That is, the "slit-shaped" in the embodiment refers not only to, for example, a rectangular shape of the beam cross section at the fundus conjugate position, but also to any quadrilateral shape, polygonal shape, or a shape extending in the length direction along any straight line or curve with any width.

[0043] Compared to the arrangement direction of two or more focal points, the aberration of the slit image on the fundus caused by the curved mirror can be minimized in a direction orthogonal to the arrangement direction of the focal points based on the common plane of the focal points including the two or more focal points. Thus, the separation of the slit image projected onto the fundus and the light receiving area can be suppressed to a minimum without being affected by the aberration of the arrangement direction of the two or more focal points of the two or more curved mirrors that relay the slit-shaped illumination light. The light receiving area is a light-receiving area of ​​the return light of the fundus conjugate position that is roughly conjugated with the fundus optics. As a result, it is not necessary to make the light-receiving area (light-receiving area) too large to include the slit image and its separation distance. Since the light-receiving area (light-receiving area) can be reduced, unnecessary light beams are not captured, so the contrast of the fundus image can be improved without the need for a high-level optical design, and the occurrence of light spots and / or ghosting can be reduced, so that a fundus image of the examined eye with higher image quality can be obtained.

[0044] The control method of the fundus imaging device of the embodiment includes one or more steps for realizing the processing executed by the processor (computer) in the fundus imaging device of the embodiment. The program of the embodiment causes the processor to execute each step of the control method of the fundus imaging device of the embodiment. The recording medium (storage medium) of the embodiment is a computer-readable non-temporary recording medium (storage medium) in which the program of the embodiment is recorded (stored).

[0045] In this specification, "processor" refers to circuits such as CPU (Central Processing Unit), GPU (Graphics Processing Unit), ASIC (Application Specific Integrated Circuit), programmable logic device (for example, SPLD (Simple Programmable Logic Device), CPLD (Complex Programmable Logic Device), FPGA (Field Programmable Gate Array)). The processor realizes the functions of the implementation mode by reading and executing the program stored in the storage circuit or storage device, for example.

[0046] Hereinafter, a case where the fundus imaging device according to the embodiment mainly includes two elliptical concave mirrors as two curved mirrors and projects a rectangular slit image onto the fundus will be described.

[0047] For convenience of explanation, the optical axis direction of the illumination light incident on the eye to be examined is set as the Z direction, the horizontal direction (left-right direction) orthogonal to the Z direction is set as the X direction, and the vertical direction (up-down direction) orthogonal to the Z direction is set as the Y direction.

[0048] <Structure>

[0049] exist Figure 1 An example of the structure of the optical system of the fundus imaging device according to the embodiment is shown in FIG. Figure 1 In FIG. 1 , a position substantially optically conjugate to the fundus of the eye under examination is illustrated as a fundus conjugate position P, and a position substantially optically conjugate to the iris (pupil) of the eye under examination is illustrated as an iris conjugate position (pupil conjugate position) Q.

[0050] The fundus photographing device 1 of the embodiment includes an illumination optical system 10, a photographing optical system 20, an aperture mirror 30 as an optical path dividing member, a relay lens 40, and a relay optical system 50. In some embodiments, the relay optical system 50 includes the relay lens 40.

[0051] (Illumination Optical System 10)

[0052] The illumination optical system 10 is a slit projection optical system, generates slit-shaped illumination light (illumination light whose beam cross-section shape is slit-shaped), and projects the generated illumination light onto the aperture mirror 30. The illumination optical system 10 includes an illumination light source 11, an iris stop 12, a relay lens 13, a slit 14, a relay lens 15, a light scanner 16, and a relay lens 17. In some embodiments, at least one of the relay lenses 13, 15, and 17 includes more than one lens.

[0053] The illumination light source 11 includes a visible light source that generates light in the visible light region. For example, the illumination light source 11 generates light in a wavelength range of 420 nm to 700 nm as the central wavelength. Such an illumination light source 11 includes, for example, an LED (Light Emitting Diode), an LD (Laser Diode), a halogen lamp, or a xenon lamp. In some embodiments, the illumination light source 11 includes a white light source or a light source that can output light of each RGB color component. In some embodiments, the illumination light source 11 includes a light source that can switch to output light in the infrared region or light in the visible light region.

[0054] The iris diaphragm 12 (specifically, the opening) can be arranged at an iris conjugate position Q, which is a position optically conjugate with the iris (pupil) of the subject's eye E or in the vicinity thereof. The iris diaphragm 12 is formed with one or more openings at positions separated from the optical axis of the optical path of the light output from the illumination light source 11. The openings formed in the iris diaphragm 12 define the incident position (incident shape) of the illumination light on the iris of the subject's eye E.

[0055] In some embodiments, the relative position between the illumination light source 11 and the opening formed in the iris diaphragm 12 can be changed. Thus, the light quantity distribution of the light passing through the opening formed in the iris diaphragm 12 can be changed.

[0056] In some embodiments, the illumination light source 11 has the function of the iris stop 12. In this case, the component that realizes the function of the iris stop 12 in the illumination light source 11 is arranged at the iris conjugate position Q.

[0057] The slit 14 (specifically, the opening) can be arranged at a fundus conjugate position P, which is a position substantially optically conjugate with the fundus Ef of the inspected eye E or in the vicinity thereof. The opening formed in the slit 14 defines the shape (irradiation pattern shape) of the illumination area of ​​the fundus Ef of the inspected eye E. The illumination light emitted from the illumination light source 11 passes through the slit 14 and is projected onto the fundus Ef as slit-shaped illumination light.

[0058] The slit 14 can be moved in the optical axis direction of the illumination optical system by means of a moving mechanism (specifically, a moving mechanism 14D described later) not shown in the figure. Thus, the position of the slit 14 can be moved according to the state of the eye E to be examined (specifically, the diopter (refractive power) or the shape of the fundus Ef).

[0059] In some embodiments, the slit 14 is configured to change at least one of the position and shape of the opening without moving in the optical axis direction according to the state of the eye E. The function of the slit 14 is realized by a liquid crystal shutter, for example.

[0060] The optical scanner 16 (specifically, the deflection surface) can be arranged at the iris conjugate position Q, which is a position optically conjugate with the iris (pupil) of the eye E to be examined or in the vicinity thereof. The optical scanner 16 is a one-axis optical scanner that changes the orientation of the deflection surface to a predetermined deflection direction. The optical scanner 16 deflects the slit-shaped illumination light formed by passing through the slit 14 in one dimension. The optical scanner 16 deflects the illumination light in a direction (specifically, an orthogonal direction) that intersects with the length direction of the slit image formed by the slit-shaped illumination light projected onto the fundus Ef. As a result, the slit image moves in a direction (scanning direction) that intersects with the length direction of the slit image.

[0061] The optical scanner 16 includes, for example, a galvanometer scanner, a MEMS (Micro Electro Mechanical System) scanner, a polygon mirror, or a resonant scanner. For example, the optical scanner 16 includes a galvanometer scanner that deflects illumination light within a predetermined deflection angle range based on a predetermined deflection direction.

[0062] In some embodiments, the optical scanner 16 is a biaxial optical scanner that deflects slit-shaped illumination light in two dimensions. For example, the optical scanner 16 includes a first scanner and a second scanner. The first scanner deflects the illumination light in such a manner that the illumination area of ​​the fundus Ef moves in a horizontal direction orthogonal to the optical axis of the illumination optical system 10. The second scanner deflects the illumination light deflected by the first scanner in such a manner that the illumination area of ​​the fundus Ef moves in a vertical direction orthogonal to the optical axis of the illumination optical system 10.

[0063] The light from the illumination light source 11 that has passed through the opening formed in the iris stop 12 passes through the relay lens 13, passes through the opening formed in the slit 14, and is output as slit-shaped illumination light. The slit-shaped illumination light emitted from the slit 14 passes through the relay lens 15, is one-dimensionally deflected by the light scanner 16, and is guided to the aperture mirror 30 through the relay lens 17.

[0064] In some embodiments, the illumination optical system 10 includes a projector having a light source, and the projector outputs slit-shaped illumination light. In this case, the projector is provided instead of Figure 1 The projector includes an illumination light source 11, an iris diaphragm 12, a relay lens 13, and a slit 14. The projector includes an LCD (Liquid Crystal Display) projector using a transmissive liquid crystal panel, an LCOS (Liquid Crystal On Silicon) projector using a reflective liquid crystal panel, and a DLP (Digital Light Processing) (registered trademark) projector using a DMD (Digital Mirror Device).

[0065] (Aperture mirror 30)

[0066] The aperture mirror 30 (specifically, an aperture portion described later) can be disposed at the iris conjugate position Q. The aperture mirror 30 is an optical path dividing member that spatially divides the optical path of the illumination light and the optical path of the return light from the subject's eye E irradiated with the illumination light.

[0067] In the aperture mirror 30, a hole portion through which the optical axis passes is formed in the center of the base, and a reflection surface for reflecting light is provided at the periphery of the center portion. Figure 1 In the embodiment, the aperture mirror 30 configured to allow the optical axis of the photographing optical system 20 to pass through the aperture portion is configured to reflect the illumination light from the illumination optical system 10 using a reflection surface provided at the peripheral portion and guide the illumination light to the subject's eye E. In some embodiments, the aperture mirror 30 configured to allow the optical axis of the illumination optical system 10 to pass through the aperture portion is configured to guide the return light from the subject's eye E to the photographing optical system 20 using a reflection surface provided at the peripheral portion. In some embodiments, the aperture mirror 30 is formed with a aperture portion through which the optical axis passes on one side of a base body, and a reflection surface for reflecting light is provided on the other side of the base body. In this case, the light passing through the aperture portion is guided to the photographing optical system 20, and the light reflected by the reflection surface is guided to the subject's eye E. Alternatively, conversely, the light passing through the aperture portion is guided to the subject's eye E, and the light reflected by the reflection surface is guided to the photographing optical system 20.

[0068] The illumination light from the illumination optical system 10 is reflected by the reflection surface formed in the peripheral portion of the hole portion of the aperture mirror 30 and guided to the relay lens 40. The return light from the subject's eye E passes through the relay lens 40, passes through the hole portion formed in the aperture mirror 30, and is guided to the imaging optical system 20.

[0069] In some embodiments, instead of the aperture mirror 30, a beam splitter, a half mirror, a polygonal mirror, or a dichroic mirror is provided.

[0070] (Photographic Optical System 20)

[0071] The photographing optical system 20 receives the return light from the inspected eye E that has passed through the hole formed in the aperture mirror 30 as a slit light receiving optical system. The return light from the inspected eye E is scattered light (reflected light) of the illumination light incident on the inspected eye E. In some embodiments, the return light from the inspected eye E includes scattered light (reflected light) of the illumination light incident on the inspected eye E and fluorescence using the illumination light incident on the inspected eye E as excitation light and its scattered light.

[0072] The photographing optical system 20 includes an image sensor 21 and a focus lens 22 .

[0073] The focusing lens 22 is movable in the optical axis direction of the photographing optical system 20 by a moving mechanism (specifically, a moving mechanism 22D described later) not shown in the figure. Thus, the return light from the eye E can be formed into an image on the light receiving surface of the image sensor 21 in accordance with the state of the eye E.

[0074] The image sensor 21 realizes the function of a two-dimensional image sensor as a pixelated light receiver. The light receiving surface (detection surface, imaging surface) of the image sensor 21 can be arranged at the fundus conjugate position P. The image sensor 21 can be set to a light receiving area (light receiving area) that can be virtually moved at the fundus conjugate position P.

[0075] For example, the light receiving result of the image sensor 21 is imported and read by a rolling shutter method. In some embodiments, the light receiving result of the image sensor 21 is imported and read by a global shutter method that can change or move the light receiving area. In some embodiments, the control unit described later controls the reading of the light receiving result by controlling the image sensor 21. In some embodiments, the image sensor 21 can automatically output the light receiving result of a predetermined line together with the information indicating the light receiving position.

[0076] Such an image sensor 21 includes, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor. In this case, the image sensor 21 includes a plurality of pixels (light-receiving devices) arranged in a row direction and a plurality of pixels arranged in a column direction. Specifically, the image sensor 21 includes a plurality of pixels arranged in two dimensions, a plurality of vertical signal lines, and a plurality of horizontal signal lines.

[0077] In some implementations, the image sensor 21 includes, for example, a CCD (Charge Coupled Device) image sensor.

[0078] By introducing (reading) the light receiving result of the return light into such an image sensor 21 in a rolling shutter manner, an image in a light-receivable area corresponding to a desired virtual opening shape extending in the row direction is acquired. Such control is disclosed in, for example, Patent Document 2 or U.S. Patent No. 8,237,835.

[0079] The return light from the subject's eye E irradiated with the illumination light from the illumination optical system 10 passes through the hole formed in the aperture mirror 30 , is transmitted through the focusing lens 22 , and forms an image on the light receiving surface of the image sensor 21 .

[0080] In some embodiments, one or more relay lenses are disposed between the focusing lens 22 and the image sensor 21 .

[0081] (Relay optical system 50)

[0082] The relay optical system 50 is arranged between the relay lens 40 and the inspected eye E. The relay optical system 50 relays the slit image formed by the slit-shaped illumination light generated by the illumination optical system 10 to the fundus Ef of the inspected eye E. The relay optical system 50 includes a reflective optical system having a function of expanding the field angle. In this case, the relay optical system 50 may also include a refractive optical system such as an aberration correction lens. In some embodiments, the relay optical system 50 does not have a function of expanding the field angle.

[0083] exist Figure 2 and Figure 3 Shown in Figure 1 A specific structural example of the relay optical system 50. Figure 2 A configuration example of the relay optical system 50 when viewed from above (XZ plane) is schematically shown. Figure 3 The following schematically shows an example of the structure of the relay optical system 50 when viewed from the lateral direction (YZ plane). Figure 2 and Figure 3 In, with Figure 1 The same parts are denoted by the same reference numerals, and the description thereof will be appropriately omitted.

[0084] like Figure 2 and Figure 3 As shown, the relay optical system 50 includes a first elliptical concave mirror 51 and a second elliptical concave mirror 52 .

[0085] (First elliptical concave mirror 51)

[0086] The reflecting surface of the first elliptical concave mirror 51 is a concave elliptical surface. The first elliptical concave mirror 51 is an example of a curved mirror or a concave mirror.

[0087] The first elliptical concave mirror 51 has two optically conjugate focal points (a first focal point F1 and a second focal point F2). The relay lens 40 is arranged so that the iris conjugate position (pupil conjugate position) Q substantially coincides with the first focal point F1.

[0088] (Second elliptical concave mirror 52)

[0089] The reflecting surface of the second elliptical concave mirror 52 is a concave elliptical surface. The second elliptical concave mirror 52 is an example of a curved mirror or a concave mirror.

[0090] The second elliptical concave mirror 52 has two optically conjugated focuses (a first focus F3 and a second focus F4). The second elliptical concave mirror 52 is configured so that the first focus F3 roughly coincides with the second focus F2 of the first elliptical concave mirror 51. In some embodiments, the second elliptical concave mirror 52 is configured so that the conjugate position of the first focus F3 and the second focus F2 or its vicinity roughly coincides, and the conjugate position of the second focus F2 is a position optically conjugate with the second focus F2 of the first elliptical concave mirror 51. The eye E (iris) to be examined is configured at the second focus F4 of the second elliptical concave mirror 52. That is, the second elliptical concave mirror 52 is configured so that the second focus F4 roughly coincides with the eye position to be examined where the eye E to be examined is configured.

[0091] Moreover, if Figure 2 As shown, the first elliptical concave mirror 51 and the second elliptical concave mirror 52 are configured so that the two focal points (first focal point F1 and second focal point F2) of the first elliptical concave mirror 51 and the two focal points (first focal point F3 and second focal point F4) of the second elliptical concave mirror 52 are configured in approximately the same plane (focus sharing plane PL). In addition, the slit 14 is configured so that the length direction of the slit image formed by the slit-shaped illumination light projected onto the fundus Ef is approximately parallel to the focus sharing plane PL. In some embodiments, when the slit 14 is aligned, the length direction of the slit image formed by the slit-shaped illumination light projected onto the fundus Ef is configured on the focus sharing plane PL.

[0092] exist Figure 4 The length direction of the slit image and Figure 3 The relationship between the focal points of the first elliptical concave mirror 51 and the second elliptical concave mirror 52. Figure 4 In, with Figure 3 The same parts are denoted by the same reference numerals, and the description thereof will be appropriately omitted.

[0093] Here, the length direction of the slit image of the fundus Ef is represented by vector L, and the direction orthogonal to the length direction of the slit image is represented by vector S. In addition, the vector from the second focus F4 of the second elliptical concave mirror 52 toward the first focus F3 is represented by vector f1, and the vector from the second focus F2 of the first elliptical concave mirror 51 toward the first focus F1 is represented by vector f2. If the normal vector of the focal point common plane PL is represented by vector n, then vector n is represented as in formula (1). At this time, as shown in formula (2), the length direction of the slit image and the focal points of the first elliptical concave mirror 51 and the second elliptical concave mirror 52 are arranged so as to be parallel to the above-mentioned vector S and vector n.

[0094] [Formula 1]

[0095]

[0096] exist Figures 5 to 8 2 shows the relationship between the focus of the first elliptical concave mirror 51 and the focus of the second elliptical concave mirror 52 according to the embodiment and the slit image projected onto the fundus oculi Ef. Figures 5 to 8 A wireframe diagram showing an example of the three-dimensional positional relationship between the first elliptical concave mirror 51, the second elliptical concave mirror 52, and the subject's eye E. Figures 5 to 8 , the length direction (Ld) of the slit image incident on the first elliptical concave mirror 51 and the length direction (Ld) of the slit image projected onto the fundus Ef of the eye E to be examined are illustrated.

[0097] Figure 5 A wireframe diagram showing the relationship between the first elliptical concave mirror 51, the second elliptical concave mirror 52, and the longitudinal direction Ld of the slit image when viewed from the lateral direction (X direction). Figure 6 A wireframe diagram showing the relationship between the first elliptical concave mirror 51, the second elliptical concave mirror 52, and the length direction Ld of the slit image when viewed from the side opposite to the reflection surface of the second elliptical concave mirror 52 is shown. Figure 7 A wireframe diagram showing the relationship between the first elliptical concave mirror 51, the second elliptical concave mirror 52, and the longitudinal direction Ld of the slit image when viewed from the upper direction (Y direction) is shown. Figure 8 A wireframe diagram showing the relationship between the first elliptical concave mirror 51, the second elliptical concave mirror 52 and the length direction Ld of the slit image when viewed from an oblique direction is shown. Figures 5 to 8 In, with Figure 2 and Figure 3 The same parts are denoted by the same reference numerals, and the description thereof will be appropriately omitted.

[0098] For example, Figure 2As shown, the first focus F1, the second focus F2 of the first elliptical concave mirror 51, and the first focus F3 and the second focus F4 of the second elliptical concave mirror 52 are arranged on the same plane (focus sharing plane PL). As described above, the illumination optical system 10 projects the slit image whose length direction Ld is parallel to the above-mentioned focus sharing plane onto the fundus Ef of the inspected eye E by causing the slit-shaped illumination light to enter the first elliptical concave mirror 51 in such a manner that the length direction Ld of the slit image is substantially parallel to the above-mentioned focus sharing plane. More specifically, the illumination optical system 10 projects the slit image whose length direction Ld is parallel to the above-mentioned focus sharing plane onto the fundus Ef of the inspected eye E by causing the slit-shaped illumination light whose length direction Ld of the slit image is arranged on the above-mentioned focus sharing plane to enter the first elliptical concave mirror 51. The illumination optical system 10 scans the fundus Ef with the illumination light by scanning the slit image in a direction orthogonal to the length direction Ld using the optical scanner 16.

[0099] In the above-described structure, the slit-shaped illumination light from the illumination optical system 10 is reflected by the reflection surface of the first elliptical concave mirror 51 and guided to the second focus F2 of the first elliptical concave mirror 51. The illumination light guided to the second focus F2 (first focus F3) is guided to the reflection surface of the second elliptical concave mirror 52, reflected by the reflection surface, and guided to the subject's eye E arranged at the second focus F4 of the second elliptical concave mirror 52.

[0100] The illumination light guided to the eye E passes through the pupil and enters the eye, irradiating the fundus Ef. The return light from the eye E passes through the pupil and is emitted to the outside of the eye E, travels in the opposite direction on the same path as the incoming path, and is guided to the first focus F1 of the first elliptical concave mirror 51. As described above, the return light guided to the first focus F1 passes through the hole formed in the hole mirror 30 and is guided to the photographing optical system 20. In the photographing optical system 20, the return light is received by the light receiving surface of the image sensor 21, and the light receiving result of the return light in the light receiving area set in the light receiving surface is introduced.

[0101] exist Figures 9A to 9C Schematically shows slit-shaped illumination light and the light-receiving area of ​​the image sensor 21. Fig. 9A The opening SL formed in the slit 14 is schematically shown. Fig. 9B The light-receivable area LA in the light-receiving surface SR of the image sensor 21 is schematically shown. Fig. 9C The slit image SL0 projected onto the fundus Ef and the light-receivable area LA0 on the light-receiving surface of the image sensor 21 are schematically shown.

[0102] Fig. 9A The light from the illumination light source 11 passing through the opening SL shown in the figure is along the longitudinal direction. Figure 2As described above, the slit-shaped illumination light is deflected by the optical scanner 16, passes through the pupil of the inspected eye E with the aid of the first elliptical concave mirror 51 and the second elliptical concave mirror 52, enters the eye, and is projected onto the fundus Ef. Fig. 9C As shown, the optical scanner 16 makes the illumination area defined by the slit image SL0 be parallel to the length direction ( Figure 3 The scanning is performed by moving in a direction orthogonal to the dd′ direction.

[0103] like Fig. 9B As shown in FIG. 1 , the image sensor 21 is configured to virtually move the light-receiving area LA of the light-receiving surface SR. This can prevent the decrease in contrast, flare and / or ghosting caused by receiving unnecessary light from the eye E. The image sensor 21 changes the position of the light-receiving area LA on the light-receiving surface SR in synchronization with the movement of the illumination area of ​​the illumination light in the fundus Ef. Specifically, as shown in FIG. Fig. 9C As shown in FIG. 1 , the light-receiving area LA of the image sensor 21 is set corresponding to the light-receiving area LA0 in the fundus Ef so as to include the range of the slit image SL0 in the fundus Ef. Figure 2 The light-receiving area LA is set in a band in a direction orthogonal to the bb′ direction, and is synchronized with the movement of the slit image SL0 in the fundus Ef. The image sensor 21 moves the light-receiving area LA of the light-receiving surface SR in sequence corresponding to the light-receiving area LA0 in a manner including the range of the slit image SL0.

[0104] Ideally, the slit image SL0 and the light-receivable area LA0 preferably overlap in the fundus Ef, but due to aberrations of the optical system, the light-receivable area LA0 needs to be wider than the slit image SL0.

[0105] exist Fig. 10A 2 is a diagram for explaining the operation of a fundus imaging device according to a comparative example of the embodiment. Fig. 10A A side view (Side View) when the subject's eye E scanned by the slit-shaped illumination light is viewed from the X direction, and a top view (Top View) when the subject's eye E scanned by the slit-shaped illumination light is viewed from the Y direction are schematically shown.

[0106] In the comparative example of the embodiment, the longitudinal direction of the slit image is perpendicular to the focal common plane, and the fundus Ef is scanned in a direction perpendicular to the longitudinal direction of the slit image (ie, the focal common plane coincides with or is parallel to the scanning direction SD).

[0107] In this comparative example, the slit image SIA0 projected onto the fundus Ef moves along the scanning direction SD. In this case, due to the aberration of the optical system, the illumination area IA0 (IA1) illuminated by the illumination light beam IL and the light receiving area SA0 (SA1) on the light receiving surface of the image sensor 21 are separated further from the optical axis. Therefore, in order to suppress the decrease in the amount of light received by the light receiving light beam RL from the light receiving area SA0, it is necessary to Fig. 9C The light-receiving area LA0 is wider than the slit image SL0.

[0108] exist Fig. 10B 2 is a diagram for explaining the operation of the fundus imaging device 1 according to the embodiment. Fig. 10B and Fig. 10A Similarly, a side view (Side View) of the subject's eye E scanned by the slit-shaped illumination light as viewed from the X direction and a top view (Top View) of the subject's eye E scanned by the slit-shaped illumination light as viewed from the Y direction are schematically shown.

[0109] In the embodiment, as described above, the longitudinal direction of the slit image coincides with or is substantially parallel to the focal point common plane, and the fundus Ef is scanned in a direction orthogonal to the longitudinal direction of the slit image.

[0110] That is, in the embodiment, the slit image SIA1 projected onto the fundus Ef moves along the scanning direction SD. Compared to the arrangement direction of two or more focal points, the aberration of the slit image on the fundus caused by a curved mirror such as an elliptical concave mirror is smallest in a direction orthogonal to the arrangement direction of the focal points with the focal common plane including the two or more focal points as a reference. Therefore, even far away from the optical axis, the separation between the illumination area IA0 (IA1) illuminated by the illumination light beam IL and the light receiving area SA0 (SA1) can be suppressed to a minimum. Therefore, there is no need to suppress the reduction in the amount of light received by the light receiving light beam RL from the light receiving area SA0, and it is possible to Fig. 9C The separation between the light-receiving area LA0 and the slit image SL0 is minimized, thereby improving the contrast and significantly reducing the occurrence of light spots and / or ghosting.

[0111] In addition, Fig. 10A and Fig. 10B The figure shows that the illumination beam IL and the imaging beam RL pass through the upper part and the lower part of the iris respectively, but the present invention is not limited thereto. For example, the illumination beam IL and the imaging beam RL may be spatially separated in the iris, and the illumination beam IL may pass through the peripheral part and the imaging beam RL may pass through the central part.

[0112] In some embodiments, at least one of the first elliptical concave mirror 51 and the second elliptical concave mirror 52 is a convex mirror (e.g., an elliptical convex mirror) whose reflective surface is formed into a convex shape. In some embodiments, at least one of the first elliptical concave mirror 51 and the second elliptical concave mirror 52 is a curved mirror whose reflective surface is a free-form surface.

[0113] In the fundus photographing device 1, in addition to Figure 1 In addition to the structure shown, an alignment optical system for aligning the eye E to be examined and the optical system is provided.

[0114] In addition, the fundus photographing device 1 may have a structure for providing a function accompanying the examination. For example, a fixation optical system for projecting a sight mark (fixation mark) onto the fundus Ef of the eye E to be examined may be provided in the fundus photographing device 1, and the sight mark (fixation mark) is used to make the eye E to be examined fixate. Furthermore, any member or unit such as a component for supporting the face of the examinee (chin rest, forehead stop, etc.) may be provided in the fundus photographing device 1.

[0115] In the embodiment, the fundus Ef of the inspected eye E can be focused by moving the slit 14 and / or the focusing lens 22, but the structure of the embodiment is not limited thereto. In some embodiments, the fundus photographing device is configured to be able to move the entire optical system (illumination optical system 10, photographing optical system 20, aperture mirror 30 and relay lens 40, or illumination optical system 10, photographing optical system 20, aperture mirror 30, relay lens 40, first elliptical concave mirror 51 and second elliptical concave mirror 52) by means of a moving mechanism not shown.

[0116] The aperture mirror 30 is an example of the "light path dividing member" of the embodiment. The first focus F3 of the second elliptical concave mirror 52 is an example of the "third focus of the second elliptical concave mirror" of the embodiment. The second focus F4 of the second elliptical concave mirror 52 is an example of the "fourth focus of the second elliptical concave mirror" of the embodiment.

[0117] exist Fig.11 FIG. 4 shows a configuration example of a processing system of the fundus imaging device 1 according to the embodiment. Fig.11 In, with Figure 1 to Figure 3 The same parts are denoted by the same reference numerals, and the description thereof will be appropriately omitted.

[0118] The processing system of the fundus imaging device 1 is configured with the control unit 60 as the center. The control unit 60 controls each unit of the fundus imaging device 1.

[0119] The control unit 60 includes a main control unit 61 and a storage unit 62. The functions of the main control unit 61 are realized by, for example, a processor. A computer program for controlling the fundus imaging device 1 is pre-stored in the storage unit 62. The computer program includes a program for controlling an illumination light source, a program for controlling an image sensor, a program for controlling an optical scanner, a program for image formation, and a program for a user interface. The control unit 60 performs control processing by the main control unit 61 operating according to such a computer program.

[0120] (Main control unit 61)

[0121] The main control unit 61 controls the illumination optical system 10, the imaging optical system 20, the image forming unit 70, and the user interface (UI) unit 80.

[0122] The control of the illumination optical system 10 includes control of the illumination light source 11 , control of the moving mechanism 14D, control of the light scanner 16 , and the like.

[0123] Control of the illumination light source 11 includes turning on and off the light source, adjusting the light amount, adjusting the aperture, and the like.

[0124] The moving mechanism 14D moves the slit 14 in the optical axis direction of the illumination optical system 10. The main control unit 61 outputs a control signal to the moving mechanism 14D, thereby moving the slit 14 in the moving direction corresponding to the control signal by the amount of movement corresponding to the control signal. For example, an actuator that generates a driving force for moving the moving mechanism 14D and a transmission mechanism that transmits the driving force are provided in the fundus imaging device 1. The actuator is composed of, for example, a pulse motor. The transmission mechanism is composed of, for example, a combination of gears, or a rack and a pinion. The moving mechanism 14D receives the driving force generated by the actuator from the transmission mechanism, and the actuator is controlled by the main control unit 61 to move the slit 14 in the optical axis direction.

[0125] The control of the optical scanner 16 includes the control of the angle of the deflection surface that deflects the illumination light. By controlling the angle of the deflection surface, the deflection direction (scanning direction) of the illumination light can be controlled. By controlling the angle range of the deflection surface, the scanning range (scanning start position and scanning end position) can be controlled. By controlling the change speed of the angle of the deflection surface, the scanning speed can be controlled.

[0126] In some embodiments, when the orientation of the focal common plane is changeable, the optical scanner 16 is configured to change the deflection direction of the illumination light in conjunction with the change in the orientation of the deflected focal common plane.

[0127] The control of the photographing optical system 20 includes control of the image sensor 21 , control of the moving mechanism 22D, and the like.

[0128] The control of the image sensor 21 includes setting control of the light-receiving area on the light-receiving surface, control for reading the light-receiving result in a rolling shutter manner (for example, setting the light-receiving size corresponding to the size of the illumination pattern, etc.). In addition, the control of the image sensor 21 includes reset control, exposure control, charge transfer control, output control, etc.

[0129] The moving mechanism 22D moves the focus lens 22 in the optical axis direction of the photographing optical system 20. The main control unit 61 outputs a control signal to the moving mechanism 22D, thereby moving the focus lens 22 in the moving direction corresponding to the control signal by the amount of movement corresponding to the control signal. For example, an actuator that generates a driving force for moving the moving mechanism 22D and a transmission mechanism that transmits the driving force are provided in the fundus photographing device 1. The actuator is composed of, for example, a pulse motor. The transmission mechanism is composed of, for example, a combination of gears, or a rack and a pinion. The moving mechanism 22D receives the driving force generated by the actuator, and moves the focus lens 22 in the optical axis direction. The actuator is controlled by the main control unit 61.

[0130] The control of the image forming section 70 includes image forming control for forming an image of the subject's eye E based on the light reception result obtained by the image sensor 21 .

[0131] The control of the UI unit 80 includes control of a display device, control of an operation device (input device), and the like.

[0132] (Storage Unit 62)

[0133] The storage unit 62 stores various data. Examples of the data stored in the storage unit 62 include the light reception result obtained by the image sensor 21, the image data of the image formed by the image forming unit 70, and the inspected eye information. The inspected eye information includes information related to the inspected eye such as the patient ID or name, and information related to the inspected eye such as identification information of the left eye / right eye.

[0134] In addition, the storage unit 62 stores various programs and data for operating the fundus imaging device 1 .

[0135] (Image Forming Unit 70)

[0136] The image forming unit 70 can form a light-receiving image (fundus image) corresponding to an arbitrary light-receiving area based on the light-receiving result read from the image sensor 21 by the rolling shutter method. The image forming unit 70 can sequentially form light-receiving images corresponding to the light-receiving area, and form an image of the subject's eye E based on the formed plurality of light-receiving images. The various images (image data) formed by the image forming unit 70 are stored in, for example, the storage unit 62.

[0137] For example, the image forming unit 70 includes a processor, and realizes the above-mentioned functions by performing processing according to a program stored in a storage unit or the like.

[0138] (UI part 80)

[0139] The UI unit 80 has a function for exchanging information between the user and the fundus photographing device 1. The UI unit 80 includes a display device and an operating device. The display device may include a display unit, or may include other display devices. The display device displays various information. The display device includes, for example, a liquid crystal display, which receives control from the main control unit 61 and displays the above information. The information displayed on the display device includes information corresponding to the control result of the control unit 60, information (image) corresponding to the calculation result of the image forming unit 70, etc. The operating device includes various hardware keyboards and / or software keyboards. The main control unit 61 receives the operation content of the operating device, and can output control signals corresponding to the operation content to each part. At least a part of the operating device and at least a part of the display device can be integrated. A touch panel display is an example thereof.

[0140] <Work>

[0141] Next, an operation example of the fundus imaging device 1 according to the embodiment will be described.

[0142] exist Fig.12 2 shows an operation example of the fundus imaging device 1 according to the embodiment. Fig.12 A flowchart showing an operation example of the fundus imaging device 1 according to the embodiment. Fig.12 The main control unit 61 performs the processing according to the computer program. Fig.12 Processing shown.

[0143] exist Fig.12 In the present invention, the inspected eye E is pre-arranged at a predetermined inspected eye position (the second focus F4 of the second elliptical concave mirror 52), and the illumination range (scanning range) of the illumination light of the fundus Ef is predetermined.

[0144] (S1: Focus)

[0145] First, the main control unit 61 controls at least one of the moving mechanism 14D and the moving mechanism 22D to adjust the focal position of the illumination optical system 10 and the focal position of the imaging optical system 20 with respect to the fundus Ef of the eye E to be examined.

[0146] (S2: Light up the lighting source)

[0147] Next, the main control unit 61 controls the illumination light source 11 to light the illumination light source 11 .

[0148] Light output from the illumination light source 11 passes through the opening formed in the iris diaphragm 12 , transmits through the relay lens 13 , passes through the opening formed in the slit 14 , transmits through the relay lens 15 , and is guided to the aperture mirror 30 as slit-shaped illumination light by means of the light scanner 16 and the relay lens 17 .

[0149] (S3: Deflection control of illumination light, setting of light-receiving area of ​​light-receiving surface)

[0150] Next, the main control unit 61 starts deflection control of the illumination light by controlling the optical scanner 16. In the deflection control of the illumination light, the direction of the deflection surface is set to a predetermined deflection direction so as to illuminate a predetermined illumination range (scanning range) in the fundus oculi Ef, and the direction of the deflection surface is sequentially changed within a predetermined deflection angle range. That is, the main control unit 61 starts scanning the fundus oculi Ef with the illumination light.

[0151] In some embodiments, the main control unit 61 controls the light scanner 16 in synchronization with the movement of the light-receivable area that can be arbitrarily set in the image sensor 21 to perform deflection control of the illumination light.

[0152] In some embodiments, the main control unit 61 controls the image sensor 21 to set the light-receiving range of the return light in the light-receiving surface corresponding to the illumination area of ​​the illumination light in the fundus Ef. For example, the illumination range of the illumination light in the fundus Ef can be determined based on the deflection angle of the deflection surface of the light scanner 16. The main control unit 61 can set the light-receiving area in the light-receiving surface of the image sensor 21 corresponding to the deflection direction of the deflection surface of the light scanner 16 that is sequentially changed.

[0153] The illumination light guided to the hole mirror 30 is reflected by the reflection surface of the peripheral portion of the hole portion, passes through the relay lens 40, is focused on the first focus F1 of the first elliptical concave mirror 51, is guided to the reflection surface of the first elliptical concave mirror 51, and is reflected by the reflection surface. The illumination light reflected by the reflection surface of the first elliptical concave mirror 51 is guided to the reflection surface of the second elliptical concave mirror 52 via the second focus F2 (first focus F3) of the first elliptical concave mirror 51. The illumination light guided to the reflection surface of the second elliptical concave mirror 52 is reflected by the reflection surface, enters the eye of the subject E arranged at the second focus F4 of the second elliptical concave mirror 52, and irradiates the fundus Ef.

[0154] The return light from the inspected eye E, including the return light from the fundus Ef, travels in the opposite direction on the same path as the incoming path, passes through the hole formed in the aperture mirror 30, passes through the focusing lens 22, and is received by the light receiving surface of the image sensor 21. The light receiving surface of the image sensor 21 is set with a light receiving area of ​​the return light corresponding to the illumination area of ​​the illumination light of the fundus Ef, suppresses the influence of unnecessary scattered light, and receives only the return light from the fundus Ef.

[0155] (S4: End?)

[0156] Next, the main control unit 61 determines whether to end the scanning of the illumination light for the fundus Ef. For example, the main control unit 61 can determine whether to end the scanning of the illumination light for the fundus Ef by determining whether the deflection angle of the deflection surface of the aperture mirror 30 that is sequentially changed is within a predetermined deflection angle range.

[0157] If it is determined that the scanning of the illumination light for the fundus Ef is completed (S4: Yes), the operation of the fundus imaging device 1 moves to step S5. If it is determined that the scanning of the illumination light for the fundus Ef is not completed (S4: No), the operation of the fundus imaging device 1 moves to step S3.

[0158] (S5: Acquiring an Image)

[0159] In step S4, when it is determined that the scanning of the illumination light for the fundus Ef is finished (S4: Yes), the main control unit 61 controls the image forming unit 70 to form an image of the subject's eye E based on the light reception result read from the image sensor 21. In some embodiments, the image forming unit 70 sequentially forms light reception images based on the light reception result read from the image sensor 21 in step S3, and forms an image of the subject's eye E based on the formed plurality of light reception images.

[0160] The operation of the fundus imaging device 1 is completed as described above (End).

[0161] As described above, according to the embodiment, the slit 14 is arranged so that the focal plane including the four focal points of the two elliptical concave mirrors is substantially parallel to the length direction of the slit image projected onto the fundus Ef, and the slit image is scanned in a manner such that the slit image moves in a direction orthogonal to the length direction of the slit image, so there is no need to set up an additional correction optical system, and a wide-angle shooting field angle can be ensured with a low-cost and compact structure, and the contrast is improved, and the occurrence of flare and / or ghosting is suppressed. In addition, a high-level optical design is not required.

[0162] Furthermore, by making the scanning length variable, the scanning range of the illumination light can be arbitrarily set.

[0163] <First Modification>

[0164] The structure of the fundus imaging device of the embodiment is not limited to the structure of the fundus imaging device 1 of the embodiment. For example, the fundus imaging device 1 of the embodiment may further include an OCT optical system.

[0165] In the following, in the embodiments, a case where a method using a swept source type OCT is used for measurement or imaging is described in particular, but the structure of the embodiments can also be applied to a fundus imaging device using other types of OCT (eg, spectral domain type).

[0166] Hereinafter, a fundus imaging device according to a first modified example of the embodiment will be described, focusing on differences from the fundus imaging device 1 of the embodiment.

[0167] <Structure>

[0168] exist Fig.13 2 shows an example of the structure of the optical system of the fundus imaging device according to the first modified example of the embodiment. Fig.13 In, with Figure 1 The same parts are denoted by the same reference numerals, and the description thereof will be appropriately omitted.

[0169] The structure of the optical system of the fundus photographing device 1a of the first modified example of the embodiment is different from the structure of the optical system of the fundus photographing device 1 of the embodiment in that the structure of the optical system of the fundus photographing device 1 is added with an OCT optical system 100 and a dichroic mirror 90. The dichroic mirror 90 is arranged between the relay lens 40 and the relay optical system 50 as an optical path coupling and separation component (optical path dividing component). In some embodiments, the dichroic mirror 90 is arranged between the aperture mirror 30 and the relay lens 40.

[0170] The dichroic mirror 90 is an optical path coupling and separation component that spatially divides the optical path of the illumination light and the optical path of the OCT optical system 100 (couples the optical path of the illumination light and the optical path of the OCT optical system 100). The dichroic mirror 90 reflects the measurement light from the OCT optical system 100 and guides it to the relay lens 40, and reflects the return light of the measurement light from the subject's eye E and guides it to the OCT optical system 100. In addition, the dichroic mirror 90 transmits the illumination light guided by the relay lens 40, and transmits the return light from the subject's eye E and guides it to the relay lens 40.

[0171] (OCT optical system 100)

[0172] exist Fig.14 Shown in Fig.13 An example of a structure of an OCT optical system 100. Fig.14 In, with Fig.13 The same parts are denoted by the same reference numerals, and the description thereof will be appropriately omitted.

[0173] The OCT optical system 100 is provided with an optical system for performing OCT measurement (or OCT photography) on the inspected eye E. The optical system is an interference optical system that divides light from a wavelength scanning light source into measurement light and reference light, causes the return light of the measurement light from the inspected eye E to interfere with the reference light via the reference optical path to generate interference light, and detects the interference light. The detection result (detection signal) of the interference light by the interference optical system is an interference signal indicating the spectrum of the interference light, and is sent to the image forming unit 70a and the data processing unit 75a described later.

[0174] The OCT light source 101 is similar to a conventional fundus imaging device of a scanning source type, and is configured to include a wavelength scanning type light source that can scan the wavelength of the emitted light. The wavelength scanning type light source is configured to include, for example, a resonator and a laser light source that emits light with a central wavelength of 1050 nm. The OCT light source 101 changes the output wavelength over time in the near-infrared wavelength band that is invisible to the human eye.

[0175] Light L0 output from OCT light source 101 is guided to polarization controller 103 by optical fiber 102 and its polarization state is adjusted. Polarization controller 103 adjusts the polarization state of light L0 guided in optical fiber 102 by applying stress to optical fiber 102 formed into a loop from the outside, for example.

[0176] The light L0 whose polarization state is adjusted by the polarization controller 103 is guided to the fiber coupler 105 by the optical fiber 104 and is split into the measurement light LS and the reference light LR.

[0177] The reference light LR is guided to the collimator 111 by the optical fiber 110 and converted into a parallel light beam, and is guided to the optical path length changing unit 114 via the optical path length correction component 112 and the dispersion compensation component 113. The optical path length correction component 112 acts to make the optical path length of the reference light LR consistent with the optical path length of the measurement light LS. The dispersion compensation component 113 acts to make the dispersion characteristics between the reference light LR and the measurement light LS consistent.

[0178] The optical path length changing unit 114 can Fig.14 The optical path length of the reference light LR is changed by moving in the direction of the arrow shown. The optical path length of the reference light LR is changed by this movement. The change of the optical path length is used to correct the optical path length and adjust the interference state according to the axial length of the eye E to be examined. The optical path length changer 114 is configured to include, for example, a corner prism and a moving mechanism for moving the corner prism. In this case, the corner prism of the optical path length changer 114 turns the traveling direction of the reference light LR formed into a parallel light beam by the collimator 111 back in the opposite direction. The optical path of the reference light LR incident on the corner prism is parallel to the optical path of the reference light LR emitted from the corner prism.

[0179] The reference light LR passing through the optical path length changer 114 is converted from a parallel beam into a focused beam by the collimator 116 via the dispersion compensation component 113 and the optical path length correction component 112, and is incident on the optical fiber 117. The reference light LR incident on the optical fiber 117 is guided to the polarization controller 118, and its polarization state is adjusted, and is guided to the attenuator 120 by the optical fiber 119 to adjust the light amount, and is guided to the optical fiber coupler 122 by the optical fiber 121.

[0180] On the other hand, the measuring light LS generated by the fiber coupler 105 is guided by the optical fiber 127 and formed into a parallel beam by the collimator lens unit 140. The measuring light LS formed into a parallel beam is deflected one-dimensionally or two-dimensionally by the optical scanner (OCT optical scanner) 150.

[0181] The collimator lens unit 140 includes a collimator lens disposed on the optical axis of the interferometer optical system included in the OCT optical system 100. The collimator lens is connected to the OCT optical system 100 and forms a beam of measurement light emitted from the end of an optical fiber that guides the measurement light LS into a parallel beam. The end of the optical fiber is disposed at, for example, a fundus conjugate position P.

[0182] The optical scanner 150 (deflection surface) can be arranged at the iris conjugate position Q. In the case of deflecting the illumination light in one dimension, the optical scanner 150 includes a galvanometer scanner that deflects the measurement light LS within a predetermined deflection angle range based on a predetermined deflection direction. In the case of deflecting the illumination light in two dimensions, the optical scanner 150 includes a first galvanometer scanner and a second galvanometer scanner. The first galvanometer scanner deflects the measurement light LS in a manner that moves the irradiation position in a horizontal direction (for example, X direction) orthogonal to the optical axis of the OCT optical system 100. The second galvanometer scanner deflects the measurement light LS deflected by the first galvanometer scanner in a manner that moves the irradiation position in a vertical direction (for example, Y direction) orthogonal to the optical axis of the OCT optical system 100. As a scanning method for moving the irradiation position of the measurement light LS of the optical scanner 150, for example, there are horizontal scanning, vertical scanning, cross scanning, radial scanning, circular scanning, concentric circle scanning, spiral scanning, reset scanning, etc.

[0183] The measurement light LS deflected by the optical scanner 150 passes through the focusing lens 151, is reflected by the dichroic mirror 90, is guided to the reflection surface of the first elliptical concave mirror 51, and is guided to the subject's eye E on the same path as the illumination light from the illumination optical system 10. The focusing lens 151 can move along the optical path of the measurement light LS (the optical axis of the OCT optical system 100). The focusing lens 151 is controlled by a control unit (control unit 60a) described later, and moves along the optical path of the measurement light LS by a moving mechanism not shown in the figure.

[0184] The measurement light LS reflected by the reflection surface of the second elliptical concave mirror 52 passes through the pupil of the subject's eye E at the second focus F4 (the subject's eye position) and enters the eye. The measurement light LS is scattered (including reflection) at each depth position of the subject's eye E. The return light of the measurement light LS including such backscattered light travels in the opposite direction on the same path as the incoming light and is guided to the fiber coupler 105, and reaches the fiber coupler 122 via the optical fiber 128.

[0185] The fiber coupler 122 generates interference light by combining (interfering) the measurement light LS incident through the optical fiber 128 and the reference light LR incident through the optical fiber 121. The fiber coupler 122 generates a pair of interference lights LC by branching the interference lights of the measurement light LS and the reference light LR at a predetermined branching ratio (e.g., 1:1). The pair of interference lights LC emitted from the fiber coupler 122 are guided to the detector 125 by the optical fibers 123 and 124, respectively.

[0186] The detector 125 is, for example, a balanced photo diode, and has a pair of photodetectors that detect a pair of interference lights LC respectively, and outputs the difference between their detection results. The detector 125 sends its detection result (interference signal) to the DAQ (Data Acquisition System) 130. The clock KC is provided from the OCT light source 101 to the DAQ 130. The clock KC is generated in the OCT light source 101 in synchronization with the output timing of each wavelength scanned (scanned) in a predetermined wavelength range by means of a wavelength scanning type light source. The OCT light source 101 generates the clock KC based on the result of detecting these synthetic lights after optically delaying one of the two branch lights obtained by branching the light L0 of each output wavelength. The DAQ 130 samples the detection result of the detector 125 based on the clock KC. The DAQ 130 sends the sampled detection result of the detector 125 to the image forming unit 70a and the data processing unit 75a, etc. The image forming unit 70a (or the data processing unit 75a) performs Fourier transform or the like on the spectrum distribution based on the detection result obtained by the detector 125, for example, in each scan (each A line) of a series of wavelength scans, thereby forming a reflection intensity curve of each A line. Furthermore, the image forming unit 70a forms image data by imaging the reflection intensity curve of each A line.

[0187] In addition, Fig.14 In the embodiment, the optical path length difference between the measurement light and the reference light is changed by changing the optical path length of the reference light, but the structure of the embodiment is not limited to this. For example, the optical path length difference between the measurement light and the reference light may be changed by changing the optical path length of the measurement light.

[0188] exist Fig.152 shows an example of the configuration of a processing system of a fundus imaging device 1a according to a first modified example of the embodiment. Fig.15 In, with Fig.11 , Fig.13 or Fig.14 The same parts are denoted by the same reference numerals, and the description thereof will be appropriately omitted.

[0189] The structure of the processing system of the fundus imaging device 1a of the first variant example differs from the structure of the processing system of the fundus imaging device 1 of the embodiment in that a control unit 60a is provided instead of the control unit 60; an image forming unit 70a is provided instead of the image forming unit 70; and a data processing unit 75a and an OCT optical system 100 are added.

[0190] The control unit 60a includes a main control unit 61a and a storage unit 62a. In addition to the control that can be executed by the control unit 60, it also controls the image forming unit 70a, the data processing unit 75a, and the OCT optical system 100. The function of the main control unit 61a is the same as that of the main control unit 61, and is realized by a processor, for example. Like the storage unit 62, a computer program for controlling the fundus imaging device 1a is pre-stored in the storage unit 62a. The computer program includes a program for controlling an illumination light source, a program for controlling an image sensor, a program for controlling an optical scanner, a program for image formation, a program for data processing, a program for controlling an OCT optical system, and a program for a user interface. The control unit 60a performs control processing by the main control unit 61a operating according to such a computer program.

[0191] The main control unit 61 a controls each part of the illumination optical system 10 , the imaging optical system 20 , the image forming unit 70 a , the data processing unit 75 a , the OCT optical system 100 , and the UI unit 80 .

[0192] The control of the OCT optical system 100 includes control of the OCT light source 101, operation control of the polarization controllers 103 and 118, movement control of the optical path length change unit 114, operation control of the attenuator 120, control of the detector 125, control of the DAQ 130, control of the optical scanner 150, control of the moving mechanism 151D, etc.

[0193] The control of the OCT light source 101 includes turning on and off the light source, adjusting the light quantity, adjusting the aperture, etc. The control of the detector 125 includes adjusting the exposure of the detection element, adjusting the gain, and adjusting the detection rate, etc. The control of the optical scanner 150 includes controlling the scanning direction, scanning position, scanning range, and scanning speed performed by the optical scanner 150, etc.

[0194] The moving mechanism 151D moves the focusing lens 151 in the optical axis direction of the OCT optical system 100. The main control unit 61a outputs a control signal to the moving mechanism 151D, thereby moving the focusing lens 151 in the moving direction corresponding to the control signal by an amount corresponding to the control signal. For example, an actuator that generates a driving force for moving the moving mechanism 151D and a transmission mechanism that transmits the driving force are provided in the fundus imaging device 1. The actuator is composed of, for example, a pulse motor. The transmission mechanism is composed of, for example, a combination of gears, or a rack and a pinion. The moving mechanism 151D receives the driving force generated by the actuator and moves the focusing lens 151 in the optical axis direction. The actuator is controlled by the main control unit 61a. In this way, the focus position of the measurement light LS can be changed. The focus position of the measurement light LS is equivalent to the depth position (z position) of the beam waist of the measurement light LS.

[0195] The control of the image forming unit 70 a includes not only image forming control for forming an image of the subject's eye E based on the light reception result obtained by the image sensor 21 , but also OCT image forming control based on the interference light detection result obtained by the OCT optical system 100 .

[0196] The control of the data processing unit 75 a includes image processing control of the image formed by the image forming unit 70 a , image analysis processing control, and the like.

[0197] The image forming unit 70a, like the image forming unit 70, can form a light-receiving image (fundus image) corresponding to any light-receiving area based on the light-receiving result read from the image sensor 21. The image forming unit 70a sequentially forms light-receiving images corresponding to the light-receiving areas, and can form an image of the subject's eye E based on the formed plurality of light-receiving images.

[0198] In addition, the image forming unit 70a forms image data of an OCT image (tomographic image) based on the detection signal input from the DAQ130 (detector 125) and the pixel position signal input from the control unit 60a. The OCT image formed by the image forming unit 70a includes an A-scan image, a B-scan image, and the like. The B-scan image is formed, for example, by arranging the A-scan image in the B-scan direction. This processing is the same as that of the conventional scanning source type OCT, including noise removal (noise reduction), filtering, dispersion compensation, FFT (Fast Fourier Transform) and other processing. In the case of other types of OCT devices, the image forming unit 70a performs known processing corresponding to its type. The various images (image data) formed by the image forming unit 70a are stored in the storage unit 62a, for example.

[0199] The data processing unit 75a processes an image formed based on the light reception result obtained by the photographing optical system 20 or data obtained by performing OCT measurement on the subject eye E. The data processing unit 75a can perform various image processing or analysis processing on the image formed by the image forming unit 70a. For example, the data processing unit 75a performs various correction processing such as brightness correction of the image.

[0200] The data processing unit 75a performs well-known image processing such as interpolation processing for interpolating pixels between OCT images to form image data of a three-dimensional image of the fundus Ef. In addition, the image data of a three-dimensional image refers to image data in which the pixel position is defined by a three-dimensional coordinate system. The image data as a three-dimensional image has image data composed of voxels arranged in three dimensions. The image data is called volume data or voxel data, etc. When displaying an image based on volume data, the data processing unit 75a performs rendering processing (volume rendering or MIP (Maximum Intensity Projection), etc.) on the volume data to form image data of a simulated three-dimensional image when observed from a specific line of sight direction. The simulated three-dimensional image is displayed on the display device included in the UI unit 80.

[0201] In addition, the image data as a three-dimensional image may be formed into stack data of a plurality of tomographic images. The stack data is image data obtained by three-dimensionally arranging a plurality of tomographic images obtained along a plurality of scanning lines based on the positional relationship of the scanning lines. That is, the stack data is image data obtained by expressing a plurality of tomographic images defined by originally independent two-dimensional coordinate systems in a three-dimensional coordinate system (i.e., embedding them in a three-dimensional space).

[0202] The data processing unit 75a can form B-mode images (longitudinal sections, axial sections), C-mode images (cross-sectional images, horizontal sections), projection images, shadow maps, etc. of arbitrary cross sections by performing various renderings on the acquired three-dimensional data sets (volume data, stack data, etc.). Images of arbitrary cross sections such as B-mode images and C-mode images are formed by selecting pixels (pixels, voxels) on a specified cross section from the three-dimensional data set. The projection image is formed by projecting the three-dimensional data set in a predetermined direction (Z direction, depth direction, axial direction). The shadow map is formed by projecting a portion of the three-dimensional data set (for example, partial data corresponding to a specific layer) in a predetermined direction. Images such as C-mode images, projection images, and shadow maps that use the front side of the examined eye as a viewpoint are called front images (en-face images).

[0203] The data processing unit 75a can construct a B-mode image and a frontal image (vascular enhancement image, angiogram) in which the retinal blood vessels and choroidal blood vessels are enhanced based on the data (e.g., B-scan image data) collected in time series by OCT. For example, by repeatedly scanning substantially the same part of the subject eye E, time series OCT data can be collected.

[0204] In some embodiments, the data processing unit 75a compares the time-series B-scan images obtained by B-scanning substantially the same part, converts the pixel value of the part where the signal intensity changes into a pixel value corresponding to the change amount, thereby constructing an enhanced image in which the change part is enhanced. Furthermore, the data processing unit 75a extracts information on the predetermined thickness amount of the desired part from the constructed multiple enhanced images, constructs an en-face image, and thus forms an OCTA image.

[0205] The OCT image also includes images generated by the data processing unit 75 a (for example, a three-dimensional image, a B-mode image, a C-mode image, a projection image, a shadowgraph, and an OCTA image).

[0206] Furthermore, the data processing unit 75a performs predetermined analysis processing on the image formed based on the light reception result obtained by the photographing optical system 20, the detection result of the interference light obtained by the OCT measurement, or the OCT image formed based on the detection result. The predetermined analysis processing includes: determining the predetermined part (tissue, lesion) of the inspected eye E; calculating the distance (interlayer distance), area, angle, ratio, density between the designated parts; performing operations using the designated calculation formula; determining the shape of the predetermined part; calculating the statistical values ​​of these; calculating the distribution of the measured values ​​and statistical values; image processing based on the results of these analysis processing, etc. The predetermined tissues include blood vessels, optic nerve head, fovea, macula, etc. The predetermined lesions include vitiligo, hemorrhage, etc.

[0207] The fundus imaging device 1a may further include a moving mechanism that moves the OCT optical system 100 in a one-dimensional direction or a two-dimensional direction that intersects the optical axis of the OCT optical system 100. In this case, the main control unit 61a controls the moving mechanism to move the OCT optical system 100 in a one-dimensional direction or a two-dimensional direction that intersects the optical axis of the OCT optical system 100 relative to the dichroic mirror 90. Thus, the scanning range of the optical scanner 150 using the OCT optical system 100 can be moved, and the OCT scanning of the fundus Ef in a wide-angle scanning range can be performed.

[0208] The dichroic mirror 90 is an example of the “optical path coupling and separation member” of the embodiment.

[0209] <Work>

[0210] Next, an operation example of the fundus imaging device 1 a according to the first modified example of the embodiment will be described.

[0211] The fundus photographing device 1a can perform OCT measurement using the OCT optical system 100 in parallel with the scanning control of the fundus Ef using the slit-shaped illumination light from the illumination optical system 10. In some embodiments, the fundus photographing device 1a performs OCT measurement using the OCT optical system 100 in a state where the scanning control of the fundus Ef using the slit-shaped illumination light from the illumination optical system 10 is stopped. Hereinafter, the control of the OCT measurement that can be performed in parallel with the scanning control of the fundus Ef using the slit-shaped illumination light is described.

[0212] exist Fig.16 2 shows an operation example of the fundus imaging device 1 a according to the first modified example of the embodiment. Fig.16 The flowchart is a flowchart showing an operation example of the fundus imaging device 1a according to the first modification. Fig.16 The main control unit 61a operates according to the computer program to execute Fig.16 Processing shown.

[0213] exist Fig.16 In the embodiment, the eye E to be examined is pre-configured at a predetermined eye position to be examined (the second focus F4 of the second elliptical concave mirror 52).

[0214] (S11: Setting scanning range)

[0215] First, the main control unit 61a sets the scanning range of the optical scanner 150. The main control unit 61a can set the scanning start position, scanning end position, scanning speed (scanning frequency), etc. of the optical scanner 150 together with the scanning range.

[0216] In some embodiments, the user can specify the scanning mode or the working mode by operating the operating device of the UI unit 80. When the scanning mode (e.g., horizontal scanning, vertical scanning) is specified by the user's operation of the operating device, the main control unit 61a analyzes the operation information from the operating device to determine the specified scanning mode. When the working mode is specified by the user's operation of the operating device, the main control unit 61a analyzes the operation information to determine the scanning mode (e.g., horizontal scanning, vertical scanning) pre-specified in the specified working mode (OCT measurement mode).

[0217] (S12: Turn on the OCT light source)

[0218] Next, the main control unit 61a controls the OCT light source 101 to light up the OCT light source 101. In some embodiments, the main control unit 61a and Fig.12The lighting control of the illumination light source 11 in step S2 shown is synchronously performed in step S12.

[0219] In some embodiments, the main control unit 61a performs focus adjustment control and polarization adjustment control. For example, after the main control unit 61a controls the moving mechanism 151D to move the focusing lens a predetermined distance, it controls the OCT optical system 100 to perform OCT measurement. The main control unit 61a causes the data processing unit 75a to determine the focus state of the measurement light LS based on the detection result of the interference light obtained by the OCT measurement. For example, the data processing unit 75a analyzes the detection result of the interference light obtained by the OCT measurement, thereby calculating a predetermined evaluation value related to the image quality of the OCT image, and determines the focus state based on the calculated evaluation value. When it is determined that the focus state of the measurement light LS is inappropriate based on the determination result of the data processing unit 75a, the main control unit 61a controls the moving mechanism 151D again, and repeats until it is determined that the focus state is appropriate.

[0220] In addition, for example, after the main control unit 61a controls at least one of the polarization controllers 103 and 118 to change the polarization state of at least one of the light L0 and the measurement light LS by a predetermined amount, it controls the OCT optical system 100 to perform OCT measurement, and causes the image forming unit 70a to form an OCT image based on the detection result of the acquired interference light. The main control unit 61a causes the data processing unit 75a to determine the image quality of the OCT image obtained by the OCT measurement. When it is determined that the polarization state of the measurement light LS is not appropriate based on the determination result of the data processing unit 75a, the main control unit 61a controls the polarization controllers 103 and 118 again, and repeats until it is determined that the polarization state is appropriate.

[0221] (S13: Execute OCT scan)

[0222] Next, the main control unit 61a controls the optical scanner 150 to deflect the measurement light LS generated based on the light L0 emitted from the OCT light source 101, and uses the deflected measurement light LS to scan a predetermined portion of the fundus Ef of the inspected eye E. The detection result of the interference light acquired by the OCT measurement is sampled in the DAQ 130 and stored in the storage unit 62a or the like as an interference signal.

[0223] (S14: End?)

[0224] Next, the main control unit 61a determines whether to end the OCT scan of the fundus Ef. For example, the main control unit 61a can determine whether to end the OCT scan of the fundus Ef by determining whether the deflection angle of the deflection plane of the optical scanner 150 that is sequentially changed is within a predetermined deflection angle range.

[0225] If it is determined that the OCT scan of the fundus Ef is completed (S14: Yes), the operation of the fundus imaging device 1a proceeds to step S15. If it is determined that the OCT scan of the fundus Ef is not completed (S14: No), the operation of the fundus imaging device 1a proceeds to step S13.

[0226] (S15: Forming OCT image)

[0227] In step S14, when it is determined that the OCT scan of the fundus Ef is finished (S14: Yes), the main control unit 61a causes the image forming unit 70a to form a plurality of A scan images of the fundus Ef along the B scan direction based on the interference signal acquired by performing the OCT scan in step S13. In some embodiments, the main control unit 61a controls the data processing unit 75a to form OCT images such as three-dimensional OCT images, B-mode images, C-mode images, projection images, shadow images, and OCTA images.

[0228] The operation of the fundus imaging device 1 a is completed as described above (End).

[0229] As described above, according to the first variant of the embodiment, in addition to the effects obtained by the embodiment, OCT measurement (OCT photography) can be performed on any position of the fundus observed at a wide angle without sharing an optical scanner for OCT scanning and an optical scanner for deflecting illumination light.

[0230] <Second Modification>

[0231] The structure of the fundus imaging device of the embodiment is not limited to the structure of the above-mentioned embodiment or the first modification example thereof. Figure 2 and Figure 3 In the structure shown, three or more curved mirrors (aspherical mirrors) may be provided to replace the first elliptical concave mirror 51 and the second elliptical concave mirror 52 .

[0232] In the second modification, two concave mirrors and one convex mirror are provided instead of the first elliptical concave mirror 51 and the second elliptical concave mirror 52 .

[0233] Hereinafter, a fundus imaging device according to a second modified example of the embodiment will be described, focusing on differences from the fundus imaging device 1 of the embodiment.

[0234] exist Fig.17 2 shows an example of the configuration of an optical system of a fundus imaging device 1b according to a second modified example of the embodiment. Fig.17 In, with Figure 3 The same parts are denoted by the same reference numerals, and the description thereof will be appropriately omitted.

[0235] The structure of the fundus photographing device 1b of the second variant example is different from the structure of the fundus photographing device 1 of the embodiment in that a reflecting mirror 53 as a plane mirror, a hyperbolic concave mirror 54 as a concave mirror, a hyperbolic convex mirror 55 as a convex mirror, and an elliptical concave mirror 56 as a concave mirror are provided to replace the first elliptical concave mirror 51 and the second elliptical concave mirror 52.

[0236] The reflecting mirror 53 reflects the slit-shaped illumination light from the illumination optical system 10 and guides it to the hyperbolic concave mirror 54. The reflecting mirror 53 also guides the return light from the inspected eye E reflected by the hyperbolic concave mirror 54 to the relay lens 40. In some embodiments, the fundus imaging device 1b has a structure in which the reflecting mirror 53 is omitted.

[0237] By deflecting the optical axis by the reflecting mirror 53 , the dimension of the optical system of the fundus imaging device 1 b in the depth direction (z direction) can be reduced.

[0238] (Hyperbolic concave mirror 54)

[0239] The hyperbolic concave mirror 54 has a concave reflecting surface. The reflecting surface of the hyperbolic concave mirror 54 is a hyperbolic surface. The hyperbolic concave mirror 54 is an example of a concave mirror. One of the focal points of the hyperbolic concave mirror 54 is a first focal point F1.

[0240] (Hyperbolic convex mirror 55)

[0241] The hyperbolic convex mirror 55 has a convex reflecting surface. The reflecting surface of the hyperbolic convex mirror 55 is a hyperbolic surface. The hyperbolic convex mirror 55 is an example of a convex mirror. One of the focal points of the hyperbolic convex mirror 55 is a second focal point F2.

[0242] (Elliptical concave mirror 56)

[0243] The reflecting surface of the elliptical concave mirror 56 is a concave elliptical surface. The elliptical concave mirror 56 is an example of a concave mirror.

[0244] The elliptical concave mirror 56 has two optically conjugated focal points (a first focal point F3 and a second focal point F4). The elliptical concave mirror 56 is configured so that the first focal point F3 roughly coincides with the second focal point F2 of the hyperbolic convex mirror 55. In some embodiments, the elliptical concave mirror 56 is configured so that the first focal point F3 roughly coincides with the optically conjugated position of the second focal point F2 of the hyperbolic convex mirror 55 (the conjugated position of the second focal point F2) or the vicinity thereof. The eye to be examined E is configured at the second focal point F4 of the elliptical concave mirror 56. That is, the elliptical concave mirror 56 is configured so that the second focal point F4 roughly coincides with the eye to be examined position where the eye to be examined E is configured.

[0245] In such a structure, the slit-shaped illumination light passing through the relay lens 40 is focused on the first focus F1, reflected by the reflecting surface of the reflecting mirror 53, reflected by the concave reflecting surface of the hyperbolic concave mirror 54, reflected by the convex reflecting surface of the hyperbolic convex mirror 55, reflected by the reflecting surface of the elliptical concave mirror 56, and guided to the inspected eye E arranged at the second focus F4 of the elliptical concave mirror 56.

[0246] The illumination light guided to the inspected eye E passes through the pupil and enters the eye, irradiating the fundus Ef. The return light from the fundus Ef (the inspected eye E) passes through the pupil and is emitted to the outside of the inspected eye E, travels in the opposite direction on the same path as the incoming path, and is guided to the first focus F1 of the hyperbolic concave mirror 54. As described above, the return light guided to the first focus F1 passes through the relay lens 40, passes through the hole formed in the aperture mirror 30, and is guided to the photographing optical system 20.

[0247] In some embodiments, at least one of the hyperbolic concave mirror 54 and the hyperbolic convex mirror 55 is a parabolic mirror. In some embodiments, at least one of the hyperbolic concave mirror 54, the hyperbolic convex mirror 55 and the elliptical concave mirror 56 is formed such that the reflecting surface is a free-form surface.

[0248] [effect]

[0249] A fundus imaging device according to an embodiment or a modified example thereof will be described.

[0250] The first mode of implementation is a fundus photographing device (1, 1a, 1b) including two or more curved mirrors (a first elliptical concave mirror 51 and a second elliptical concave mirror 52, or a reflecting mirror 53, a hyperbolic concave mirror 54, a hyperbolic convex mirror 55 and an elliptical concave mirror 56), an illumination optical system (10), an image sensor (21) and a control unit (60 (main control unit 61), 60a (main control unit 61a)). The illumination optical system uses two or more curved mirrors to illuminate the fundus (Ef) of the eye to be examined (E) with slit-shaped illumination light, and illuminates the fundus while moving the illumination area. The image sensor can be arranged at a fundus conjugate position (P) that is roughly optically conjugate with the fundus, and receives return light from the eye to be examined. The control unit controls at least the illumination optical system. The length direction of the image (slit image) formed by the illumination light at the fundus is substantially parallel to a plane (focus common plane PL) including two or more focal points (first focal point F1, second focal point F2, first focal point F3, and second focal point F4) of two or more curved mirrors. The control unit controls the illumination optical system in such a manner that the image moves in a direction intersecting (orthogonal) with the length direction at the fundus.

[0251] According to such a method, the separation between the slit image on the fundus and the light-receiving area (light-receiving area) of the return light at the fundus conjugate position that is substantially optically conjugate with the fundus can be suppressed to a minimum without being affected by the aberration of the two or more curved mirrors that relay the slit-shaped illumination light. As a result, the contrast can be improved with a low-cost and simple structure without the need for a high-level optical design, and the occurrence of flare and / or ghosting can be reduced, so that a fundus image of the inspected eye with higher image quality can be obtained.

[0252] In a second mode of the embodiment, according to the first mode, the illumination optical system includes an optical scanner (16) that can be arranged at an iris conjugate position (Q) that is substantially optically conjugate with the iris of the inspected eye, and the fundus is illuminated movably by deflecting the illumination light by the optical scanner.

[0253] According to such an aspect, by controlling the deflection of the illumination light by the optical scanner, it is possible to acquire a high-quality image of the fundus of the eye to be examined with a simple configuration.

[0254] In a third aspect of the embodiment, according to the first aspect or the second aspect, the illumination optical system includes a light source (illumination light source 11) and a slit (14) that can be arranged at a fundus conjugate position, and slit-shaped illumination light is generated by irradiating light from the light source to the slit.

[0255] According to such an aspect, slit-shaped illumination light can be generated with a simple configuration, and a high-quality fundus image of the eye to be examined can be acquired.

[0256] In a fourth aspect of the embodiment, according to the third aspect, the slit is movable in the optical axis direction of the illumination optical system according to the diopter (refractive power) of the eye to be examined.

[0257] According to such an aspect, the fundus can be illuminated with high-brightness illumination light regardless of the visual acuity of the eye to be examined.

[0258] A fifth embodiment of the present invention comprises, according to any one of the first to fourth embodiments, an iris diaphragm (12) having an opening formed at a position eccentric from the optical axis, which can be arranged at an iris conjugate position (Q) that is roughly optically conjugate with the iris of the eye to be examined; and an optical path dividing component (aperture mirror 30) arranged between two or more curved mirrors and the image sensor to spatially divide the optical path of the illumination light and the optical path of the return light.

[0259] According to such an aspect, the illumination light entering the eye and the return light emitted from the eye to the outside can be pupil-divided with a simple configuration, and a higher-quality fundus image can be acquired.

[0260] In a sixth aspect of the embodiment, according to the fifth aspect, a focusing lens (22) is provided between the image sensor and the optical path dividing member and is movable in the optical axis direction.

[0261] According to such an aspect, regardless of the visual acuity (refractive power) of the eye to be examined, the return light from the eye to be examined can be imaged on the light receiving surface of the image sensor, and a higher quality fundus image can be acquired.

[0262] In a seventh aspect of the embodiment, according to any one of the first to sixth aspects, the two or more curved mirrors are arranged so as to share at least one of the two or more focal points.

[0263] According to such an aspect, an image formed by illumination light can be relayed with high accuracy using a simple configuration, and a higher-quality fundus image can be acquired.

[0264] In an eighth aspect of the embodiment, according to any one of the first to seventh aspects, the two or more curved mirrors include elliptical concave mirrors.

[0265] According to such a method, a higher-quality fundus image can be acquired using an elliptical concave mirror manufactured with high precision.

[0266] In a ninth aspect of the embodiment, according to any one of the first to eighth aspects, the two or more curved mirrors are a first elliptical concave mirror (51) and a second elliptical concave mirror (52). The first focus (F1) of the first elliptical concave mirror is arranged at an iris conjugate position that is substantially optically conjugate with the iris of the eye to be examined, the second focus (F2) of the first elliptical concave mirror substantially coincides with the first focus (F3) of the second elliptical concave mirror, and the second focus (F4) of the second elliptical concave mirror can be arranged on the iris.

[0267] According to this aspect, it is possible to obtain a wide-angle image of the fundus with higher image quality using two elliptical concave mirrors.

[0268] In a tenth aspect of the embodiment, according to any one of the first to ninth aspects, the image sensor is a rolling shutter image sensor.

[0269] According to such a mode, a higher-quality fundus image can be acquired with a simple configuration.

[0270] The eleventh mode of the embodiment is a control method for a fundus photographing device (1, 1a, 1b) including two or more curved mirrors (a first elliptical concave mirror 51 and a second elliptical concave mirror 52, or a reflecting mirror 53, a hyperbolic concave mirror 54, a hyperbolic convex mirror 55 and an elliptical concave mirror 56), an illumination optical system (10) and an image sensor (21). The illumination optical system irradiates the fundus (Ef) of the eye to be examined (E) with slit-shaped illumination light by means of the two or more curved mirrors, and illuminates the fundus while moving the illumination area. The image sensor can be arranged at a fundus conjugate position that is roughly optically conjugate with the fundus, and receives return light from the eye to be examined. The length direction of the image (slit image) formed by the illumination light on the fundus is roughly parallel to the plane (focus common plane PL) including the two or more focal points of the two or more curved mirrors. The control method for the fundus photographing device includes a control step and an introduction step. In the control step, the illumination optical system is controlled in such a way that the above-mentioned image moves on the fundus in a direction intersecting with the above-mentioned length direction. In the introducing step, the light reception result of the return light in the light receiving area (light receiving possible area) of the light receiving surface (SR) of the image sensor corresponding to the position of the above-mentioned image of the fundus is introduced.

[0271] According to such a method, the separation between the slit image on the fundus and the light-receiving area (light-receiving area) of the return light at the fundus conjugate position that is substantially optically conjugate with the fundus can be suppressed to a minimum without being affected by the aberration of two or more curved mirrors that relay the slit-shaped illumination light. As a result, the contrast can be improved with a low-cost and simple structure without the need for a high-level optical design, and the occurrence of flare and / or ghosting can be reduced, so that a fundus image of the inspected eye with higher image quality can be obtained.

[0272] In the twelfth embodiment, according to the eleventh embodiment, the illumination optical system includes a light source (illumination light source 11) and a slit (14) that can be configured at a fundus conjugate position, and the control method of the fundus photographing device includes a slit control step of moving the slit in the optical axis direction of the illumination optical system according to the diopter of the eye being examined.

[0273] According to such a method, the fundus can be illuminated with high-brightness illumination light regardless of the visual acuity of the eye to be examined.

[0274] In a thirteenth aspect of the embodiment, according to the eleventh aspect or the twelfth aspect, the fundus photographing device includes: an iris diaphragm (12) having an opening formed at a position eccentric from the optical axis and capable of being arranged at an iris conjugate position (Q) substantially optically conjugate with the iris of the subject's eye; and an optical path dividing member (aperture mirror 30) arranged between two or more curved mirrors and the image sensor to spatially divide the optical path of the illumination light and the optical path of the return light. The control method of the fundus photographing device includes a focus control step of moving the focus lens in the direction of the optical axis.

[0275] According to such a method, regardless of the visual acuity (refractive power) of the eye to be examined, the return light from the eye to be examined can be imaged on the light receiving surface of the image sensor, and a higher quality fundus image can be acquired.

[0276] In a fourteenth aspect of the embodiment, according to any one of the eleventh to thirteenth aspects, the introducing step introduces the light reception result of the return light by a rolling shutter method.

[0277] According to such a method, a higher-quality fundus image can be acquired through simple control.

[0278] In a fifteenth aspect of the embodiment, according to any one of the eleventh to fourteenth aspects, the two or more curved mirrors are a first elliptical concave mirror (51) and a second elliptical concave mirror (52). The first focus (F1) of the first elliptical concave mirror is arranged at an iris conjugate position that is substantially optically conjugate with the iris of the subject's eye, the second focus (F2) of the first elliptical concave mirror substantially coincides with the first focus (F3) of the second elliptical concave mirror, and the second focus (F4) of the second elliptical concave mirror can be arranged on the iris.

[0279] According to this aspect, it is possible to obtain a wide-angle image of the fundus with higher image quality using two elliptical concave mirrors.

[0280] A sixteenth aspect of the embodiment is a program for causing a computer to execute each step of the method for controlling the fundus imaging device according to any one of the eleventh to fifteenth aspects.

[0281] According to such a procedure, the separation between the slit image on the fundus and the light receiving area, which is a light receiving area of ​​the return light at the fundus conjugate position that is substantially optically conjugate with the fundus, can be suppressed to a minimum without being affected by the aberration of the two or more curved mirrors that relay the slit-shaped illumination light. As a result, the contrast can be improved with a low-cost and simple structure without requiring a high-level optical design, and the occurrence of flare and / or ghosting can be reduced, so that a fundus image of the inspected eye with higher image quality can be obtained.

[0282] <Other>

[0283] The embodiment described above is merely an example for implementing the present invention, and those who wish to implement the present invention can make any modifications, omissions, additions, etc. within the scope of the gist of the present invention.

[0284] In some embodiments, a program is provided for causing a processor (computer) to execute each step of the control method of the fundus photographing device described above. Such a program can be stored in any non-temporary recording medium (storage medium) that can be read by a computer. As the recording medium, for example, a semiconductor memory, an optical disk, an optical magnetic disk (CD-ROM / DVD-RAM / DVD-ROM / MO, etc.), a magnetic storage medium (hard disk / floppy disk (FD) (registered trademark) / ZIP, etc.) can be used. In addition, the program can also be sent and received via a network such as the Internet or a LAN (local area network).

[0285] Description of Reference Numerals

[0286] 1.1a,1b Fundus photography device

[0287] 10 Illumination optical system

[0288] 11 Lighting source

[0289] 12 Iris diaphragm

[0290] 14 Slit

[0291] 16 Optical Scanner

[0292] 20 Photographic Optical System

[0293] 21 Image Sensor

[0294] 22 Focusing lens

[0295] 30 hole mirror

[0296] 40 Relay lens

[0297] 50 Relay optical system

[0298] 51 The first elliptical concave mirror

[0299] 52 Second elliptical concave mirror

[0300] 60, 60a control unit

[0301] 61, 61a main control unit

[0302] 62, 62a storage unit

[0303] 70, 70a image forming unit

[0304] 75a Data Processing Department

[0305] 80 UI Department

[0306] 90 Dichroic Mirror

[0307] 100 OCT optical system

[0308] E Eye under examination

[0309] Ef Fundus

[0310] F1, F3 first focus

[0311] F2, F4 second focus

[0312] P Fundus conjugate position

[0313] Q Iris conjugate position

Claims

1. A fundus photographing device, comprising: Two or more curved mirrors; an illumination optical system that illuminates the fundus of the eye to be examined with slit-shaped illumination light by means of the two or more curved mirrors, and illuminates the fundus while moving the illumination area; an image sensor capable of being arranged at a fundus conjugate position substantially optically conjugate with the fundus and receiving return light from the eye to be examined; as well as a control unit that controls at least the illumination optical system, The length direction of the image formed by the illumination light at the fundus is substantially parallel to a plane including the two or more focal points of the two or more curved mirrors. The control unit controls the illumination optical system so that the image moves on the fundus in a direction intersecting the longitudinal direction.

2. The fundus photographing device according to claim 1, characterized in that: The illumination optical system includes an optical scanner that can be arranged at an iris conjugate position that is substantially optically conjugate with an iris of the eye to be inspected, and the optical scanner deflects the illumination light to movably illuminate the fundus with the illumination light.

3. The fundus photographing device according to claim 1, characterized in that: The illumination optical system comprises: Light source; and The slit can be arranged at the fundus conjugate position, The slit-shaped illumination light is generated by irradiating the slit with light from the light source.

4. The fundus photographing device according to claim 3, characterized in that: The slit is movable in the optical axis direction of the illumination optical system in response to the diopter of the eye to be examined.

5. The fundus photographing device according to claim 3, characterized in that: The fundus photographing device comprises: an iris stop having an opening formed at a position eccentric from the optical axis and being displaceable at an iris conjugate position substantially optically conjugate with the iris of the eye to be examined; and The optical path dividing component is disposed between the two or more curved mirrors and the image sensor, and spatially divides the optical path of the illumination light and the optical path of the return light.

6. The fundus photographing device according to claim 5, characterized in that: The fundus photographing device comprises: The focusing lens is disposed between the image sensor and the optical path dividing member and is movable in the optical axis direction.

7. The fundus imaging device according to any one of claims 1 to 6, characterized in that: The two or more curved mirrors are configured to share at least one of the two or more focal points.

8. The fundus imaging device according to any one of claims 1 to 6, characterized in that: The two or more curved mirrors include elliptical concave mirrors.

9. The fundus imaging device according to any one of claims 1 to 6, characterized in that: The two or more curved mirrors are a first elliptical concave mirror and a second elliptical concave mirror, The first focus of the first elliptical concave mirror is arranged at an iris conjugate position which is substantially optically conjugate with the iris of the eye to be examined. The second focus of the first elliptical concave mirror roughly coincides with the third focus of the second elliptical concave mirror. The fourth focus of the second elliptical concave mirror can be arranged on the iris.

10. The fundus imaging device according to any one of claims 1 to 6, characterized in that: The image sensor is a rolling shutter image sensor.

11. A method for controlling a fundus photographing device, the fundus photographing device comprising: Two or more curved mirrors; an illumination optical system that illuminates the fundus of the eye to be examined with slit-shaped illumination light by means of the two or more curved mirrors, and illuminates the fundus while moving the illumination area; as well as The image sensor can be arranged at a fundus conjugate position that is substantially optically conjugate with the fundus and receives return light from the eye to be examined. The length direction of the image formed by the illumination light at the fundus is substantially parallel to a plane including the two or more focal points of the two or more curved mirrors. The control method of the fundus photographing device comprises: a control step of controlling the illumination optical system in such a manner that the image moves on the fundus in a direction intersecting the longitudinal direction; as well as The step of introducing is to introduce a light reception result of the return light in a light receiving area of ​​a light receiving surface of the image sensor corresponding to the position of the image in the fundus.

12. The control method of the fundus photographing device according to claim 11, characterized in that: The illumination optical system comprises: Light source; and The slit can be arranged at the fundus conjugate position, The control method of the fundus photographing device includes a slit control step of moving the slit in the optical axis direction of the illumination optical system in response to the diopter of the eye to be examined.

13. The control method of the fundus photographing device according to claim 11, characterized in that: The fundus photographing device comprises: an iris stop having an opening formed at a position eccentric from the optical axis and capable of being arranged at an iris conjugate position substantially optically conjugate with the iris of the eye to be examined; an optical path dividing component, disposed between the two or more curved mirrors and the image sensor, and spatially coupling the optical path of the illumination light with the optical path of the return light; and A focusing lens is disposed between the image sensor and the optical path dividing component. The control method of the fundus imaging device includes a focus control step of moving the focus lens in an optical axis direction.

14. The control method of the fundus imaging device according to any one of claims 11 to 13, characterized in that: The introducing step introduces the light receiving result of the return light in a rolling shutter manner.

15. The control method of the fundus imaging device according to any one of claims 11 to 13, characterized in that: The two or more curved mirrors are a first elliptical concave mirror and a second elliptical concave mirror, The first focus of the first elliptical concave mirror is arranged at an iris conjugate position which is substantially optically conjugate with the iris of the eye to be examined. The second focus of the first elliptical concave mirror roughly coincides with the third focus of the second elliptical concave mirror. The fourth focus of the second elliptical concave mirror can be arranged on the iris.

16. A program, characterized in that A computer is caused to execute each step of the control method of the fundus imaging device according to any one of claims 11 to 13.

Images