Scanning fundus photography device

Abstract

To provide a scanning fundus imaging apparatus capable of appropriately acquiring a fundus image of an eye to be examined.SOLUTION: A scanning fundus imaging apparatus comprises: a first optical system having a confocal opening, which scans and irradiates an ocular fundus with light, and receives returned light of the light from the ocular fundus via the confocal opening: a second optical system different from the first optical system; a light path coupling mirror for coupling a first light path of the first optical system with a second light path of the second optical system; and a protective member that protects the light path coupling mirror. With a first ocular fundus conjugate position of the first optical system present in a common light path in the first light path and the second light path on the side of an eye to be examined and with separated light, part of light from the first optical system, advanced in a direction different from the common light path by the light path coupling mirror, a third light path of the separated light is formed. A second ocular fundus conjugate position which is mirror symmetric with the first ocular fundus conjugate position with regard to the light path coupling mirror is formed on the third light path. A wall part of the protective member is disposed spaced from the second ocular fundus conjugate position.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a scanning fundus imaging apparatus that captures an image of the fundus of a subject's eye. [Background technology]

[0002] There is known a scanning light ophthalmoscope (SLO) that acquires a fundus image of a subject's eye by scanning light. This device may include an SLO optical system and another optical system different from the SLO optical system, mainly sharing an objective lens system. For example, the device of Patent Document 1 includes an SLO optical system and an OCT (Optical Coherence Tomography) optical system. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-134896 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned device, the optical path of the SLO optical system and the optical path of the other optical system are combined by an optical path combining member. In such a configuration, the inventors found that a part of the light from the SLO optical system may be guided in an unintended direction by the optical path combining member, and may appear as an artifact on the fundus image.

[0005] In view of the above-described conventional techniques, the present disclosure has as its technical object to provide a scanning fundus photography apparatus capable of suitably acquiring a fundus image of a subject's eye. [Means for solving the problem]

[0006] A scanning fundus imaging device for imaging the fundus of a test eye includes a first optical system having a confocal aperture arranged at a position conjugate with the fundus, the first optical system scanningly irradiating the fundus with light via an objective lens and receiving return light of the light from the fundus via the confocal aperture to capture an image of the fundus of the test eye, a second optical system different from the first optical system, an optical path coupling mirror coupling a first optical path of the first optical system and a second optical path of the second optical system, and a protective member for protecting at least the optical path coupling mirror. a diopter correction means capable of correcting the diopter of the subject's eye; and a control means for controlling the diopter correction means to adjust a diopter correction amount in accordance with the diopter of the subject's eye. a first fundus conjugate position of the first optical system is present at least on a common optical path on the test eye side of the first optical path and the second optical path, a third optical path of the separated light, which is a part of the light from the first optical system, is advanced in a direction different from the common optical path by the optical path combining mirror, and a second fundus conjugate position that is mirror-symmetrical to the first fundus conjugate position with respect to the optical path combining mirror is formed on the third optical path, the diopter correction means is capable of correcting the diopter within a first movement range of the first fundus conjugate position, The wall of the protective member is Mirror symmetric to the first moving range The second fundus conjugate position The second moving range of from 、 They are placed at a distance. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is an external view of a scanning fundus photography apparatus. [Diagram 2] FIG. 2 is a diagram for explaining a photographing optical system. [Diagram 3] 11A and 11B are diagrams illustrating the relationship between the diopter correction amount and the fundus conjugate position. [Figure 4] FIG. 4 is a diagram illustrating the arrangement of walls of the imaging unit. [Diagram 5] FIG. 2 is a block diagram showing a control system of the scanning fundus photography apparatus. [Figure 6] 4A and 4B are diagrams illustrating the relationship between the angle of view for photographing an eye to be examined and a wall of an imaging unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [overview] An embodiment of a scanning fundus imaging device according to the present disclosure will be described with reference to the drawings. The items classified in < > below can be used independently or in association with each other. Note that "conjugate" in this embodiment is not necessarily limited to a perfect conjugate relationship, but includes "approximate conjugate". In other words, "conjugate" in this embodiment also includes cases where the position is shifted from the perfect conjugate position within a range permitted in relation to the technical significance of each part.

[0009] The scanning fundus imaging device of this embodiment (e.g., the scanning fundus imaging device 1) is a device that images the fundus of a test eye. The scanning fundus imaging device may be an SLO device having a first optical system (SLO optical system) described below that scans light on the fundus of the test eye. The scanning fundus imaging device may be a composite device that combines an SLO device with other devices. As an example, it may be a device combined with at least one of an optical coherence tomography device, a therapeutic laser device, etc.

[0010] For example, the scanning fundus imaging device includes a first optical system for capturing a fundus image of the subject's eye. For example, the scanning fundus imaging device includes a second optical system different from the first optical system. For example, the scanning fundus imaging device includes an optical path coupling mirror that couples a first optical path of the first optical system with a second optical path of the second optical system. For example, the scanning fundus imaging device includes a protective member that protects at least the optical path coupling mirror.

[0011] <1st optical system> For example, the first optical system may be a confocal fundus imaging optical system. For example, it may be a spot scan type optical system or a line scan type (slit scan type) optical system. For example, the first optical system (e.g., the SLO optical system 500) scans and irradiates light onto the fundus via an objective lens, and receives return light of the measurement light from the fundus via a confocal aperture, thereby capturing a fundus image of the subject's eye. That is, for example, the first optical system may be a confocal optical system in which a confocal aperture is disposed at a fundus conjugate position, and may capture a confocal front image of the fundus.

[0012] For example, the first fundus conjugate position of the first optical system is at least present on a common optical path on the subject's eye side in the first optical path of the first optical system and the second optical path of the second optical system. In other words, the first fundus conjugate position with respect to the objective lens is at least present on a common optical path on the subject's eye side. Note that such a first fundus conjugate position may be configured to be located between the objective lens and the optical path coupling mirror.

[0013] The first optical system may include a light irradiating unit (e.g., light source 56) that irradiates light onto the fundus of the subject's eye, a scanning unit (e.g., scanning unit 52) ​​that scans the fundus with light from the light irradiating unit, a confocal aperture (e.g., confocal aperture 58) that is arranged at a position conjugate with the fundus, and a light receiving unit (e.g., light receiving element 59) that receives return light from the fundus. For example, the light irradiating unit may irradiate laser light. The light irradiating unit may be configured to irradiate light other than laser light. For example, the light receiving unit may be a point sensor that detects the intensity of the received light. For example, the light receiving unit may be a one-dimensional light receiving element, a two-dimensional light receiving element, etc.

[0014] For example, the first optical system may be configured to widely scan the light on the fundus to capture a wider area of ​​the fundus. For example, the scanning unit may be configured to set the scanning angle of light on the fundus to 40 degrees or more. For example, the scanning unit may be a reflecting mirror (e.g., a galvanometer mirror, a polygon mirror, a resonant scanner, etc.). Also, for example, the scanning unit may be an acousto-optical element that changes the traveling direction of light.

[0015] The first optical system may include a diopter correction means (e.g., diopter correction unit 53) capable of correcting the diopter of the subject's eye in a first moving range of the first fundus conjugate position. The diopter correction means may correct the diopter of the first optical system according to the refractive error of the subject's eye. The diopter correction means may be configured to correct the diopter by moving a lens along the optical axis. For example, in this case, the diopter correction means may include a focusing lens (e.g., focusing lens 53a) and a drive unit (e.g., drive unit 53b) for moving the focusing lens. The diopter correction means may also be configured to correct the diopter by inserting and removing a lens on the optical axis. The diopter correction unit may also be configured to correct the diopter by changing the refractive index of the variable focus lens.

[0016] In this embodiment, the diopter correction means may be configured to be able to appropriately correct the diopter even when the refractive error of the subject's eye is large. For example, it may be possible to correct the diopter for refractive errors of -10D or less and +10D or more, which are considered to be high diopter eyes. As an example, the diopter correction amount may be adjusted to be compatible with at least -15D.

[0017] <Control means> The scanning fundus imaging device of this embodiment may include a control means (e.g., a control unit 71) for controlling the diopter correction means. The control means controls the diopter correction means to adjust the diopter correction amount according to the diopter of the subject's eye. For example, the control means may adjust the diopter correction amount by driving a drive unit for moving the lens along the optical axis, or a drive unit for inserting and removing the lens on the optical axis. Also, for example, the control means may adjust the diopter correction amount by controlling the current value applied to the variable-focus lens.

[0018] <Second optical system> For example, the second optical system may be an optical system different from the first optical system. For example, the second optical system may be an OCT optical system (e.g., the OCT optical system 300) that acquires a tomographic image of the subject's eye. For example, the second optical system may be an anterior eye imaging optical system (e.g., the anterior eye imaging optical system 200) that images the anterior eye of the subject's eye. Of course, the OCT optical system and the anterior eye imaging optical system are examples of the second optical system, and are not limited to these.

[0019] <Optical path coupling mirror> For example, the optical path combining mirror makes a part of the first optical path of the first optical system and a part of the second optical path of the second optical system into a common optical path (for example, the first common optical path 10). For example, the optical path combining mirror may be composed of at least any optical member such as a beam splitter, a dichroic mirror (for example, the dichroic mirror 12), a half mirror, etc. The optical path combining mirror transmits or reflects light incident toward the optical path combining mirror.

[0020] <Protective materials> For example, the protective member is provided to protect the optical path coupling mirror from dust, scratches, etc. For example, the protective member may be a housing (for example, the photographing unit 2) that houses each optical system. Also, for example, the protective member may be a cover that houses at least the optical path coupling mirror, separate from the housing.

[0021] <Arrangement of the first optical system and the second optical system> The independent optical path in the first optical path of the first optical system and the independent optical path in the second optical path of the second optical system may be disposed on either the reflection side or the transmission side of the optical path combination mirror. For example, the independent optical path of the first optical path may be disposed on the reflection side of the optical path combination mirror. In this case, the independent optical path of the second optical path may be disposed on the transmission side of the optical path combination mirror. Also, for example, the independent optical path of the first optical path may be disposed on the transmission side of the optical path combination mirror. In this case, the independent optical path of the second optical path may be disposed on the reflection side of the optical path combination mirror. Note that when the independent optical path of the first optical path is disposed on the transmission side of the optical path combination mirror, the reflection direction of the light by the scanning unit and the scanning direction of the fundus can be easily matched in the first optical system, so that the optical system can be prevented from becoming complicated.

[0022] In this embodiment, when the independent optical path in the first optical path of the first optical system is arranged on the transmission side of the optical path combination mirror, the reflection side of the optical path combination mirror on which the independent optical path of the second optical system is arranged may be any of the upper side, lower side, right side, and left side of the optical path combination mirror. When the independent optical path of the second optical system is arranged on the lower side of the optical path combination mirror, the second optical system is arranged lower than the first optical system. Therefore, the optical member is not positioned higher than the eye to be examined, and when the eye to be examined and the optical axis of each optical system are aligned, the device is prevented from protruding above the eye to be examined, so that the examiner can easily perform eyelid opening work, etc.

[0023] In the common optical path of the first optical path of the first optical system and the second optical path of the second optical system, an optical member may be arranged between the objective lens and the optical path combination mirror. For example, an optical path combination mirror for combining the optical paths of a third optical system different from the first optical system and the second optical system may be arranged. Of course, a member different from the optical path combination mirror may be arranged. In addition, in the common optical path of the first optical path of the first optical system and the second optical path of the second optical system, an optical member may not be arranged between the objective lens and the optical path combination mirror. In this case, the optical path combination mirror may be arranged near the objective lens, and the light from the first optical system may be guided to the objective lens without passing through an optical member after passing through the optical path combination mirror.

[0024] <Relationship between the protective member and the fundus conjugate position> For example, the separated light, which is a part of the light in the first optical system, is unintentionally caused to travel in a direction different from the common optical path by an optical path combining mirror that combines the independent optical path of the first optical path in the first optical system with the independent optical path of the second optical path in the second optical system. For example, when the independent optical path of the first optical path in the first optical system is disposed on the reflection side of the optical path combining mirror, the part of the light (separated light) in the first optical system travels in a direction different from the common optical path as transmitted light that is transmitted through the optical path combining mirror without being reflected. Also, for example, when the independent optical path of the first optical path in the first optical system is disposed on the transmission side of the optical path combining mirror, the part of the light (separated light) in the first optical system travels in a direction different from the common optical path as reflected light that is reflected through the optical path combining mirror without being transmitted through the optical path combining mirror. This forms a third optical path for the separated light.

[0025] On the third optical path of the separated light, a second fundus conjugate position is formed which is mirror-symmetrical to the first fundus conjugate position with respect to the optical path coupling mirror. For example, the first fundus conjugate position and the second fundus conjugate position differ depending on the diopter of the subject's eye. For example, the larger the diopter of the subject's eye on the minus diopter side, the farther the first fundus conjugate position is from the optical path coupling mirror on the first optical path, and correspondingly, the second fundus conjugate position is also farther from the optical path coupling mirror on the second optical path. That is, there is a first movement range of the first fundus conjugate position in which the diopter correction means can correct the diopter, and a second movement range of the second fundus conjugate position which is mirror-symmetrical to the first movement range.

[0026] For example, such separated light travels toward a wall of the protective member and is reflected by the wall of the protective member. For example, in the first optical system, the reflected light of the separated light reflected by the wall is blocked by the confocal aperture and does not reach the light receiving unit. However, depending on the diopter correction using the diopter correction means, the reflected light of the separated light reflected by the wall may reach the light receiving unit without being blocked by the confocal aperture.

[0027] For example, when the diopter correction means corrects the diopter and adjusts the first fundus conjugate position relative to the objective lens and the confocal aperture to have a conjugate relationship, the second fundus conjugate position that exists in mirror symmetry with the first fundus conjugate position also has a conjugate relationship with the confocal aperture. In this case, if the wall of the protective member and the second fundus conjugate position coincide with each other, the separated light is reflected by the wall, and the reflected light passes through the confocal aperture and reaches the light receiving unit, causing a problem that the wall of the protective member is reflected as an artifact on the fundus image.

[0028] In this embodiment, the wall of the protective member is disposed at a distance from the second fundus conjugate position so that the wall does not coincide with the second fundus conjugate position. This makes it possible to obtain a good fundus image with suppressed reflection of the protective member even if, for example, the second fundus conjugate position and the confocal aperture are adjusted to have a conjugate relationship. In addition, in this embodiment, when a configuration is made that can accommodate a wide range of diopters of the subject's eye, it is important to dispose the wall of the protective member at a distance from the diopter correction range of the second fundus conjugate position. This makes it possible to obtain a good fundus image with suppressed reflection of the protective member regardless of the diopter of the subject's eye.

[0029] When the independent optical path in the first optical path of the first optical system is disposed on the transmission side and the confocal aperture side of the optical path combining mirror, and the independent optical path in the second optical path of the second optical system is disposed on the reflection side and the lower side of the optical path combining mirror, the separated light in the first optical system is reflected toward the upper side, which is the opposite side of the independent optical path in the second optical path, with respect to the optical path combining mirror, thereby forming a third optical path and a second fundus conjugate position. In this case, by disposing the wall part of the protective member on the optical path combining mirror side at a distance from the second fundus conjugate position (second movement range of the second fundus conjugate position), it is possible to suppress the reflection of the protective member.

[0030] [Example] An example of this embodiment will be described with reference to the drawings. Fig. 1 is an external view of a scanning fundus imaging apparatus 1. As shown in Fig. 1, in this embodiment, the scanning fundus imaging apparatus 1 includes a base 101, a movable table 102, an operation unit 8, a monitor 73, a driving unit 5, a face support unit 110, an imaging unit 2, a control unit 71, and the like.

[0031] The operation unit 8 inputs a signal for operating the imaging unit 2. For example, when the operation unit 8 is tilted, a movement signal is input for moving the movable stage 102 in at least one of the left-right direction (X direction) and the front-back direction (Z direction) relative to the base 101. Also, for example, when a knob (not shown) of the operation unit 8 is rotated, a movement signal is input for moving the imaging unit 2 in the up-down direction (Y direction) relative to the base 101.

[0032] The monitor 73 displays a front image of the subject's eye E, OCT data, etc. on the screen. The monitor 73 also functions as a touch panel that also serves as the operation unit 8. That is, a movement signal for moving the imaging unit 2 is also input by operating the monitor 73.

[0033] The driving unit 5 moves the imaging unit 2 in the left-right, up-down, and front-back directions. For example, the driving unit 5 is a slide mechanism. As an example, the slide mechanism may include a motor, gears, guide rails, and the like.

[0034] The face support unit 110 supports the face of the subject. The face support unit 110 has a forehead rest 111 and a chin rest 112. The forehead of the subject comes into contact with the forehead rest 111. The chin of the subject is placed on the chin rest 112.

[0035] The photographing unit 2 houses an imaging optical system 3 (see FIG. 2) for photographing the subject's eye E. The imaging optical system 3 will be described with reference to FIG. 2. The scanning fundus imaging device 1 of this embodiment includes, as the imaging optical system 3, an SLO optical system 500, an OCT optical system 300, an alignment target projection optical system 27, an anterior eye imaging optical system 200, and the like.

[0036] In this embodiment, the optical path of the SLO optical system 500 and the optical path of the OCT optical system 300 are coupled by the dichroic mirror 12. That is, the optical axis L1 of the SLO optical system and the optical axis L2 of the OCT optical system 300 are made coaxial by the dichroic mirror 12. Further, the optical axis L2 of the OCT optical system 300 and the optical axis L3 of the anterior eye imaging optical system 200 are coupled by the half mirror 201. That is, the optical axis L2 of the OCT optical system and the optical axis L3 of the anterior eye imaging optical system 200 are made coaxial by the half mirror 201. An objective lens 11 is disposed on the common optical path 10 (common optical axis) of the SLO optical system 500, the OCT optical system 300, and the anterior eye imaging optical system 200.

[0037] Hereinafter, the OCT measurement light emitted from the OCT optical system 300 to the eye to be examined in order to acquire an OCT signal is simply referred to as measurement light. Further, the light emitted from the laser light source 56 of the SLO optical system 500 for photographing the fundus Er of the eye to be examined E is simply referred to as laser light.

[0038] <SLO optical system> The SLO optical system 500 is used to obtain a frontal image of the fundus Er. For example, the SLO optical system 500 includes a scanning unit 52, a diopter correction unit 53, a beam splitter 54, a collimating lens 55, a laser light source 56, a condenser lens 57, a confocal aperture 58, and a light receiving element 59 in addition to the objective lens 11 and the dichroic mirror 12.

[0039] The SLO optical system 500 irradiates the fundus Er with the laser light emitted from the laser light source 56. The light receiving element 59 receives the laser light reflected by the fundus Er. In this embodiment, the laser light source 56 emits laser light that is near-infrared light. As the laser light source 56, for example, an LED light source, an SLD light source, or the like may be used.

[0040] The scanning unit 52 is disposed in the optical path of the laser light. In this embodiment, the scanning unit 52 is used to scan the laser light in the transverse direction (XY direction in FIG. 1) on the fundus Er. In this embodiment, the scanning unit 52 includes two optical scanners (e.g., a polygon scanner, a galvanometer mirror, etc.), and drives the two optical scanners to two-dimensionally scan the fundus Er with the laser light from the laser light source 56. For example, the scanning angle of view of the scanning unit 52 on the fundus may be 40 degrees or more, and is 50 degrees in this embodiment. Of course, the scanning angle of view is not limited to this.

[0041] In this embodiment, the condenser lens 57, the confocal aperture 58 (for example, a pinhole plate), and the light receiving element 59 are disposed on the reflection side of the beam splitter 54. The confocal aperture 58 is disposed at a position conjugate with the fundus Er.

[0042] Here, the laser light emitted from the laser light source 56 is incident on the scanning unit 52 via the collimating lens 55, the beam splitter 54, and the diopter correction unit 53. Then, the reflection direction of the laser light is changed by the scanning unit 52. The laser light passing through the scanning unit 52 passes through the dichroic mirror 12. Furthermore, the laser light passes through the objective lens 11 and is focused on the fundus Er.

[0043] The laser light reflected by the fundus Er travels back along the optical path from the objective lens 11 to the beam splitter 54. The laser light is reflected by the beam splitter 54, passes through the condenser lens 57 and the confocal aperture 58, and is received by the light receiving element 59. A signal output from the light receiving element 59 is input to a control unit 71, which will be described later. The control unit 71 may generate a front image of the fundus Er based on the input signal, and store the image in a storage unit 72. The control unit 71 may display the generated front image on a monitor 73.

[0044] <Vision correction section> The diopter correction unit 53 corrects the diopter of the eye to be examined. The diopter correction unit 53 adjusts the diopter correction amount according to the refractive error of the eye to be examined E, and condenses the light emitted from the laser light source 56 onto the fundus Er of the eye to be examined E. For example, the diopter correction unit 53 includes a focusing lens 53a and a lens driving unit 53b for moving the focusing lens 53a in the optical axis direction. For example, the lens driving unit 53b may be configured by a motor and a slide mechanism.

[0045] FIG. 3 is a diagram for explaining the relationship between the diopter correction amount and the fundus conjugate position. FIG. 3(a) shows the case where the eye to be examined E is myopic. FIG. 3(b) shows the case where the eye to be examined E is hyperopic. In FIG. 3, an '×' is attached to the fundus conjugate position.

[0046] According to the refractive error of the eye to be examined E, the fundus conjugate position P1 on the common optical path 10 (on the optical axis L1) changes. For example, in the case of myopia, the greater the refractive error is on the minus diopter side, the closer the fundus conjugate position P1 is to the objective lens 11 (see FIG. 3(a)). Also, for example, in the case of hyperopia, the greater the refractive error is on the plus diopter side, the closer the fundus conjugate position P1 is to the dichroic mirror 12 (see FIG. 3(b)). The diopter correction unit 53 moves the focusing lens 53a by driving the lens driving unit 53b, thereby changing the conjugate position (not shown) formed at least with respect to the focusing lens 53a, and adjusts so that the fundus Er (fundus conjugate position P1) and the confocal aperture 58 are in a conjugate relationship.

[0047] In this embodiment, the diopter correction unit 53 is configured so as to be able to correct the refractive error from -15D to +15D in the eye to be examined E. At this time, the fundus conjugate position P1 corresponding to the eye to be examined E may exist in the range R1 from the position R1a to the position R1b on the optical axis L1. For example, the first fundus conjugate position when the eye to be examined E is -15D corresponds to the position R1a. Also, for example, the first fundus conjugate position when the eye to be examined E is +15D corresponds to the position R1b.

[0048] <OCT optical system> The OCT optical system 300 is used, for example, to capture a tomographic image of the tissue of the test eye E. In addition to the objective lens 11, the dichroic mirror 12, and the half mirror 201, the OCT optical system 300 may be configured to include an OCT light source that emits low coherent light, a light splitter that splits the light emitted from the light source into measurement light and reference light, a measurement optical system that guides the measurement light to the test eye E, a scanning unit that scans the measurement light in a transverse direction on the fundus of the test eye E, a reference optical system that generates reference light, and a detector that detects an interference signal due to the combination of the measurement light and the reference light. Of course, the OCT optical system 300 may have a configuration different from these. For details of the OCT optical system 300, for example, the configuration disclosed in JP 2019-134896 A may be referenced.

[0049] For example, the OCT optical system 300 splits the OCT light emitted from the OCT light source into a measurement light and a reference light by a light splitter. The measurement light reaches the fundus of the subject's eye E via a half mirror 201, a dichroic mirror 12, and an objective lens 11. The OCT optical system 300 receives interference light between the measurement light reflected by the fundus of the subject's eye E and the reference light, thereby acquiring an OCT signal of the fundus of the subject's eye E, and inputs the signal to the control unit 71. The control unit 71 may generate an OCT image of the fundus Er based on the input signal, and store the image in the storage unit 72. The control unit 71 may display the generated front image on the monitor 73.

[0050] <Alignment target projection optical system> The alignment index projection optical system 27 is used to project an alignment index toward the cornea of ​​the subject's eye E. For example, the alignment index projection optical system 27 may include at least a light source 27a for projecting the alignment index. Of course, in addition to the light source 27a, the alignment index projection optical system 27 may include optical members such as lenses and mirrors. For example, the light source 27a is arranged in a ring shape centered on the optical axis L1. The light from the light source 27a is used as alignment light for aligning the photographing unit 2 with respect to the subject's eye E, and is also used as anterior eye illumination light for illuminating the anterior eye of the subject's eye E.

[0051] <Anterior Eye Segment Imaging Optical System> The anterior eye segment imaging optical system 200 is used to obtain a frontal observation image of the anterior eye segment. In this embodiment, the anterior eye segment imaging optical system 200 includes a lens 202 and an imaging element 203 in addition to the objective lens 11, the dichroic mirror 12, and the half mirror 201. The imaging element 203 is, for example, a two-dimensional imaging element such as a CCD. The imaging element 203 images the anterior eye segment of the eye E to be examined illuminated by the light source 27a. The signal output from the imaging element 203 is input to a control unit 71 described later. The control unit 71 may generate an anterior eye segment image of the fundus Er based on the input signal and store it in the storage unit 72. The control unit 71 may display the generated frontal image on the monitor 73.

[0052] <Optical Path Sharing of SLO Optical System and OCT Optical System> The optical path of the SLO optical system 500 and the optical path of the OCT optical system 300 are combined by the dichroic mirror 12 as described above. In this embodiment, the SLO optical system 500 is arranged on the transmission side of the dichroic mirror 12, and the OCT optical system 300 is arranged on the reflection side of the dichroic mirror 12.

[0053] The dichroic mirror 12 transmits the laser light in the SLO optical system 500 (that is, the light of the wavelength emitted from the laser light source 56). More specifically, the dichroic mirror 12 transmits the laser light incident in the direction parallel to the optical axis direction of the first common optical path 10 and guides it to the first common optical path 10, and also transmits the laser light reflected by the fundus Er and guides it to the SLO optical system 500.

[0054] In this embodiment, a polygon scanner is used as one of the scanning units 52. For example, since the polygon scanner rotates at high speed, a physical load is likely to be applied to the rotation axis. By arranging the SLO optical system 500 on the transmission side of the dichroic mirror 12 and arranging the rotation axis of the polygon scanner in the vertical direction, the load can be reduced, especially compared to the case where the rotation axis is arranged in an oblique direction. In addition, by arranging the SLO optical system 500 on the transmission side, the reflection direction of the laser light by the scanning unit 52 and the scanning direction of the fundus Er can be made the same, so that it is not necessarily necessary to adjust the reflection direction of the laser light by a mirror or a lens. Therefore, it is possible to suppress the SLO optical system 500 from becoming complicated.

[0055] In this embodiment, the dichroic mirror 12 reflects the measurement light in the OCT optical system 300 (i.e., light of a wavelength emitted from an OCT light source not shown). For example, the measurement light of the OCT optical system 300 is incident on the dichroic mirror 12 from the vertical direction and is reflected by the dichroic mirror 12 in the horizontal direction. In other words, the measurement light of the OCT optical system 300 is incident on the lower side of the dichroic mirror 12 and is reflected to be guided to the first common optical path 10. This prevents the imaging unit 2 from protruding too far to a position higher than the subject's eye E, making it easier for the examiner to reach out from above the imaging unit 2 when assisting the eyelid opening of the subject's eye E, etc. The direction in which the measurement light is incident on the dichroic mirror 12 may be inclined with respect to the vertical direction.

[0056] <Artifacts appearing in the photo> 4 is a diagram for explaining the arrangement of the wall portion 100 of the imaging unit 2. Here, some of the laser light from the SLO optical system 500 may be reflected without passing through the dichroic mirror 12. For example, such a part of the laser light (hereinafter, the separated light) travels in a direction mirror-symmetrical to the common optical path 10 with respect to the dichroic mirror 12. For this reason, on the optical axis L4 of the separated light, a second fundus conjugate position P2 is unintentionally formed at a position mirror-symmetrical to the first fundus conjugate position P1 with respect to the dichroic mirror 12.

[0057] The second fundus conjugate position P2 on the optical axis L4 changes depending on the refractive error of the subject's eye E. For example, in the case of a myopic eye, the greater the refractive error on the minus diopter side, the closer the first fundus conjugate position P1 is to the objective lens 11, and the second fundus conjugate position P2 is located at a position farther away from the dichroic mirror 12. For example, in the case of a hyperopic eye, the greater the refractive error on the plus diopter side, the closer the first fundus conjugate position P1 is to the dichroic mirror 12, and the second fundus conjugate position P2 is also located at a position closer to the dichroic mirror 12. For example, when the first fundus conjugate position P1 is located at position R1a in the range R1, the second fundus conjugate position P2 is located at position R2a. For example, when the first fundus conjugate position P1 is located at position R1b, the second fundus conjugate position P2 is located at position R2b. That is, the fundus conjugate position P2 can exist in a range R2 from a position R2a to a position R2b on the optical axis L4.

[0058] For example, the separated light is reflected upward by the dichroic mirror 12, and therefore travels toward the wall 100 of the imaging unit 2 and reaches the wall 100.

[0059] Here, for example, when the wall 100 of the photographing unit 2 is located at a position Wa overlapping with the second fundus conjugate position P2 formed on the optical axis L4 of the separated light as shown in Fig. 4, the wall 100 is reflected as an artifact on the fundus image. In particular, the larger the refractive error of the subject's eye E is on the negative diopter side, the higher the possibility that the second fundus conjugate position P2 will overlap with the wall 100, and such an artifact reflection is likely to become a problem.

[0060] 4, in this embodiment, the wall 100 of the photographing unit 2 is disposed at a distance from the moving range R2 of the second fundus conjugate position P2. More specifically, the wall 100 of the photographing unit 2 is disposed at a distance from the position R2b on the optical axis L4. This prevents the second fundus conjugate position P2 from unintentionally being overlapped with the wall 100 regardless of the refractive error of the subject's eye E, and a preferable fundus image without the wall 100 being reflected can be obtained.

[0061] In this embodiment, the dichroic mirror 12 is disposed at an angle d with respect to the first common optical path 10. For example, the angle d is 45 degrees or less. Preferably, the angle d is 30 degrees to 42 degrees, and is 40 degrees in this embodiment. When the angle d of the dichroic mirror 12 is 45 degrees, the separated light is reflected vertically. However, when the angle d is an angle other than 45 degrees, the separated light is reflected obliquely, so that the optical axis L4 becomes longer and the wall 100 is less likely to be reflected. Furthermore, by setting the angle d of the dichroic mirror 12 to an angle other than 45 degrees, the intensity of the reflected wall 100 is reduced even if the wall 100 is reflected.

[0062] Note that artifacts can also be reduced by arranging the light absorbing member on the optical axis L4 without increasing the distance between the wall portion 100 and the second fundus conjugate position P2. However, if the light absorbing member and the second fundus conjugate position P2 overlap, the light absorbing member is reflected even though its strength is low, so there is a possibility that a good fundus image cannot be acquired. By arranging the wall portion 100 so as not to overlap with the second fundus conjugate position P2 as in this embodiment, the reflection of artifacts can be more effectively suppressed.

[0063] Also, by not increasing the distance between the wall 100 and the second fundus conjugate position P2 and by decreasing the distance between the objective lens 11 and the dichroic mirror 12, the artifacts can be reduced. This is because the second fundus conjugate position P2 is located closer to the dichroic mirror 12 and is less likely to overlap with the wall 100 than when the objective lens 11 and the dichroic mirror 12 are farther apart. However, in such a configuration, the dichroic mirror 12 must be designed to be larger, and the imaging unit 2 may become larger. In addition, the moving range R1 in which the first fundus conjugate position P1 moves on the optical axis L1 becomes shorter, and the diopter that can correct the refractive error of the subject's eye E is limited. If the wall 100 is arranged so as not to overlap with the second fundus conjugate position P2 as in this embodiment, it is possible to accommodate a larger refractive error of the subject's eye E, suppressing the inclusion of artifacts and suppressing the increase in size of the imaging unit 2.

[0064] <Control Unit> The control system of the scanning fundus imaging device 1 will be described with reference to Fig. 5. Fig. 5 is a block diagram showing the control system of the scanning fundus imaging device 1. Each part of the scanning fundus imaging device 1 is controlled by a control unit 71. The control unit 71 is a processing device (processor) having electronic circuits that perform control processing of each part of the scanning fundus imaging device 1 and arithmetic processing. The control unit 71 is realized by a CPU (Central Processing Unit), memory, etc. The control unit 71 is electrically connected to a storage unit 72 via a bus, etc.

[0065] The control unit 71 is electrically connected to the lens driving unit 53b of the diopter correction unit 53. The control unit 71 drives the lens driving unit 53b to move the position of the focusing lens 53a in the optical axis direction, and adjusts the diopter correction amount so as to correct the refractive error of the subject's eye E.

[0066] The control unit 71 is also electrically connected to each of the components, such as the drive unit 5, the light source 27a, the laser light source 56, the light receiving element 59, the scanning unit 52, the monitor 73, and the imaging element 203. Furthermore, the control unit 71 is also electrically connected to each of the components, such as an OCT light source (not shown) and a detector (not shown), provided in the OCT optical system 300.

[0067] The storage unit 72 stores various control programs and the like. In addition, temporary data and the like may be stored in the storage unit 72. Images obtained by the scanning fundus photography device 1 may be stored in the storage unit 72. However, this is not necessarily limited to this, and the obtained fundus images and the like may be stored in an external storage device (for example, a storage device connected to the control unit 71 via a LAN and a WAN).

[0068] [Operation] The operation of the scanning fundus imaging device 1 having the above-mentioned configuration will be described below. Note that the following description will be given taking as an example a case where the SLO optical system 500 is used to acquire a fundus image of the fundus Er of the subject's eye E.

[0069] First, when the subject places his / her forehead on the forehead rest 111 and places his / her chin on the chin rest 112, a detection signal is output from a detector (not shown). Based on the detection signal, the control unit 71 turns on the light source 27a and controls the alignment target projection optical system 27 and the anterior eye photographing optical system 3 to obtain an anterior eye image. The control unit 71 also controls the driving of the driving unit 5 based on the anterior eye image to change the positional relationship between the subject's eye E and the photographing unit 2. For example, the control unit 71 drives the driving unit 5 to adjust the positions of the optical axis L1 and the pupil center in the XY directions (see FIG. 1) so that the fundus Er can be photographed, and adjust the position in the Z direction (see FIG. 1) so that the working distance is suitable for fundus photography. For example, the method of adjusting the positional relationship between the subject's eye E and the photographing unit 2 can be the method described in JP 2013-179978 A. Of course, the examiner may operate the operating unit 8 to manually adjust the positional relationship between the subject's eye E and the photographing unit 2.

[0070] When the examiner completes the alignment of the subject's eye E with the photographing unit 2, he or she operates the operating unit 8 (monitor 73) to input an operation start signal to start photographing a fundus image. The control unit 71 turns on the laser light source 56 based on the operation start signal. It also drives the scanning unit 52 to scan the fundus Er of the subject's eye with laser light. The laser light reflected from the fundus is received by the light receiving element 59. The light receiving element 59 outputs the intensity of the received fundus reflected light. The control unit 71 forms a fundus image of the subject's eye based on the driving of the scanning unit 52 and the intensity of the fundus reflected light output by the light receiving element 59, and displays it on the monitor 73.

[0071] For example, the examiner adjusts the diopter correction amount for correcting the refractive error of the subject's eye E by operating the operation unit 8 while referring to the fundus image. The control unit 71 controls the diopter correction unit 53 based on an operation signal from the operation unit 8 to move the focusing lens 53b. For example, this causes the laser light to be focused on the fundus Er.

[0072] As described above, in this embodiment, the wall 100 of the photographing unit 2 is disposed at a distance from the position P2b on the optical axis L4. The examiner adjusts the diopter correction amount, so that the fundus Er is in focus and an appropriate fundus image in which the reflection of the wall 100 is suppressed is photographed in real time. When the examiner inputs a photographing trigger signal (e.g., a release operation signal, etc.) via the operation unit 8, the control unit 71 captures the fundus image.

[0073] As described above, in the scanning fundus imaging device 1 of this embodiment, the wall 100 of the imaging unit 2 is disposed at a distance from the second fundus conjugate position P2, so that the wall 100 and the second fundus conjugate position P2 do not overlap, and the wall 100 is prevented from appearing as an artifact on the fundus image. This makes it possible to preferably acquire a fundus image of the subject's eye.

[0074] In addition, in the scanning fundus imaging device 1 of this embodiment, the dichroic mirror 12 is disposed near the objective lens 11 in the SLO optical system 500, and the light from the SLO optical system 500 is guided to the objective lens 11 without passing through the dichroic mirror 12. For example, the overlap between the wall 100 and the second fundus conjugate position P2 can be suppressed by disposing the dichroic mirror 12 sufficiently away from the objective lens 11, but this tends to result in an increase in the size of the device because the optical system becomes longer. Even in the case where the objective lens 11 and the dichroic mirror 12 are disposed close to each other to configure the optical system to be short as in this embodiment, a fundus image in which the wall 100 is not reflected can be obtained by considering the position of the wall 100.

[0075] In addition, the scanning fundus photography device 1 of this embodiment can correct the diopter according to the refractive error of the subject's eye, and the wall portion 100 is disposed at a distance from the second fundus conjugate position P2, which is mirror-symmetrical to the first fundus conjugate position P1 according to the refractive error of the subject's eye. That is, the wall portion 100 is disposed at a distance from the range R2, in which the first fundus conjugate position P1 may exist, which is mirror-symmetrical to the range R1 in which the first fundus conjugate position P1 may exist. Therefore, even if the refractive error of the subject's eye is large and the second fundus conjugate position R2 is located farther away from the dichroic mirror 12, it is possible to prevent the wall portion 100 from being reflected on the fundus image.

[0076] In addition, in the scanning fundus imaging device 1 of this embodiment, the optical path of the SLO optical system 500 is disposed on the transmission side of the dichroic mirror 12, and the optical path of an optical system different from the SLO optical system (here, the OCT optical system 300) is disposed on the reflection side of the dichroic mirror 12. This allows the reflection direction in which the light from the SLO optical system 500 is reflected by the scanning unit 52 to be the same as the scanning direction of the fundus Er. Note that, for example, when the reflection direction of the light and the scanning direction differ, it becomes necessary to adjust each direction using a mirror or a lens. With the configuration of this embodiment, it is possible to prevent the SLO optical system 500 from becoming complicated.

[0077] In addition, in the scanning fundus imaging device 1 of this embodiment, the optical path of the SLO optical system 500 is coupled from the working distance direction of the dichroic mirror 12, and the optical path of an optical system (OCT optical system 300) different from the SLO optical system is coupled from below the dichroic mirror 12. As a result, a part of the light (separated light) from the SLO optical system 500 is reflected upward without passing through the dichroic mirror 12. For example, by disposing the OCT optical system 300 below the SLO optical system 500 in this manner, it is possible to prevent the imaging unit 2 from protruding significantly to a position higher than the subject's eye (a position higher than the objective lens 11). Therefore, when the examiner reaches out from above the scanning fundus imaging device 1 to open the subject's eyelids, the examiner can easily reach the position, and the burden on the examiner can be reduced.

[0078] [Example of transformation] In this embodiment, the case where the wall 100 may be reflected in the fundus image depending on the refractive error of the subject's eye E has been described as an example, but the present invention is not limited to this. For example, the wall 100 may be reflected depending on the scanning angle of view of the fundus Er in the SLO optical system 500. For this reason, the wall 100 may be positioned in consideration of the scanning angle of view of the fundus Er.

[0079] FIG. 6 is a diagram for explaining the relationship between the angle of view for photographing the subject's eye and the wall 100 of the photographing unit 2. The SLO optical system 500 scans the subject's eye E with laser light in the transverse direction (XY direction), so that the first fundus conjugate position P1 on the optical axis L1 and the second fundus conjugate position P2 on the optical axis L4 exist as the first fundus conjugate plane M1 and the second fundus conjugate plane M2, respectively. For example, the larger the scanning angle of view of the fundus Er, the larger each fundus conjugate plane becomes. Therefore, the larger the scanning angle of view of the fundus Er, the more the second fundus conjugate plane M2 overlaps with the wall 100, and the wall 100 is more likely to be captured as an artifact on the fundus image. However, by arranging the wall 100 in consideration of the scanning angle of view of the fundus Er, artifacts can be suppressed and a suitable fundus image can be obtained. Of course, the wall portion 100 may be disposed in consideration of both the diopter correction amount corresponding to the refractive error of the subject's eye E and the scanning angle of view of the fundus Er.

[0080] In this embodiment, the SLO optical system 500 is disposed on the transmission side of the dichroic mirror 12, and the OCT optical system 300 is disposed on the reflection side of the dichroic mirror 12, but the present invention is not limited thereto. For example, the SLO optical system 500 may be disposed on the reflection side of the dichroic mirror 12, and the OCT optical system 300 may be disposed on the transmission side of the dichroic mirror 12. In this case, some light (separated light) in the laser light of the SLO optical system 500 may be transmitted without being reflected by the dichroic mirror 12, and similarly, a fundus conjugate position is unintentionally formed on the optical path of the separated light. However, even with such a configuration, the wall portion can be prevented from being captured on the fundus image by disposing the wall portion 100 of the imaging unit 2 so as not to overlap with the fundus conjugate position.

[0081] When the SLO optical system 500 is disposed on the reflecting side of the dichroic mirror 12, the laser light of the SLO optical system 500 may be incident on the lower side of the dichroic mirror 12. This configuration prevents the imaging unit 2 from protruding too far to a position higher than the subject's eye E. Of course, the laser light may be configured to be incident on the upper side of the dichroic mirror 12, but for the above reasons, it is preferable to have the laser light incident on the lower side of the dichroic mirror 12.

[0082] In this embodiment, the optical path of the SLO optical system 500 and the optical path of the OCT optical system 300 are combined by the dichroic mirror 12, but the present invention is not limited to this. For example, even if the optical path of the OCT optical system 500 is combined with the optical path of an optical system different from the OCT optical system 500 (for example, the anterior eye imaging optical system 200, etc.), the wall 100 is reflected due to the influence of the separated light. In this case, a half mirror or the like may be used instead of the dichroic mirror 12. For example, even in such a case, an appropriate fundus image with suppressed artifacts can be obtained by arranging the wall 100 so as not to overlap with the second fundus conjugate position P2.

[0083] In this embodiment, the case where the dichroic mirror 12 and other optical members are protected by the imaging unit 2 has been described as an example, but the present invention is not limited to this. For example, the surface of the dichroic mirror 12 may be dusted or scratched, which may cause artifacts resulting from the dust or scratches to be easily reflected in the fundus image. For this reason, the imaging unit 2 may be provided with a separate protective cover for protecting at least the dichroic mirror 12. In this case, the protective cover may be a member that covers only the dichroic mirror 12. Of course, the protective cover is not limited to this, and may be a member that covers the optical members (objective lens 11 and dichroic mirror 12) arranged in the first common optical path 10, for example.

[0084] In this embodiment, even when the protective cover is provided, the wall of the protective cover is arranged not to overlap with the second fundus conjugate position P2. This makes it possible to suppress the wall of the protective cover from appearing as an artifact even if a part of the light (separated light) from the SLO optical system 500 is unintentionally reflected by the dichroic mirror 12, and to obtain a suitable fundus image.

[0085] In the above embodiment, the SLO optical system 500 is shown as an example of the first optical system. The SLO optical system 500 is a spot-scan type optical system, and takes a fundus image by two-dimensionally scanning a light beam irradiated in a spot shape on the fundus. However, as described above, a line-scan type optical system can be applied to the first optical system. In this case, in the line-scan type optical system, a line-shaped light beam is scanned in one direction on the fundus to take a fundus image. In the line-scan type optical system, a light receiving element (for example, a line sensor) may also function as a confocal aperture. In this case, by arranging the light receiving element at a fundus conjugate position, reception of stray light is suppressed even if an aperture separate from the light receiving element is not necessarily arranged at a fundus conjugate position. Note that even in the line-scan type optical system, an aperture separate from the light receiving element may be arranged at a fundus conjugate position. [Explanation of symbols]

[0086] 1. Scanning fundus photography device 10 1st common optical path 11 Objective lens 12 Dichroic mirror 52 Scanning unit 53 Diopter correction unit 58 Confocal aperture 59 Photodetector 100 wall 300 OCT optics 500 SLO optics

Claims

1. A scanning fundus photography apparatus for photographing a fundus of a subject's eye, comprising: a first optical system having a confocal aperture arranged at a position conjugate with the fundus, the first optical system scanningly irradiating the fundus with light via an objective lens and receiving return light of the light from the fundus via the confocal aperture, thereby capturing a fundus image of the test eye; a second optical system different from the first optical system; an optical path combining mirror that combines a first optical path of the first optical system and a second optical path of the second optical system; a protective member for protecting at least the optical path coupling mirror; a diopter correction means capable of correcting the diopter of the subject's eye; a control means for controlling the diopter correction means and adjusting a diopter correction amount in accordance with the diopter of the subject's eye; Equipped with a first fundus conjugate position of the first optical system is at least present on a common optical path on a test eye side in the first optical path and the second optical path, a third optical path of the separated light, which is a part of the light from the first optical system, is formed by the optical path combining mirror in a direction different from the common optical path, and a second fundus conjugate position that is mirror-symmetrical to the first fundus conjugate position with respect to the optical path combining mirror is formed on the third optical path, the diopter correction means is capable of correcting the diopter within a first movement range of the first fundus conjugate position, A scanning fundus photography apparatus, characterized in that a wall portion of the protection member is disposed at a distance from a second movement range of the second fundus conjugate position that is mirror-symmetrical to the first movement range.

2. 2. The scanning fundus photography apparatus according to claim 1, the first optical system has the optical path combination mirror in the vicinity of the objective lens, and the light passes through the optical path combination mirror and is then guided to the objective lens without passing through any optical member; 2. A scanning fundus photography apparatus, comprising: a first fundus conjugate position located between the objective lens and the optical path coupling mirror;

3. In the scanning fundus photography apparatus of claim 1 or 2, an independent optical path of the first optical path in the first optical system is disposed on a transmission side of the optical path combination mirror, and an independent optical path of the second optical path in the second optical system is disposed on a reflection side of the optical path combination mirror, The separated light is a part of the light from the first optical system that is reflected by the optical path combining mirror without passing through the optical path combining mirror.

4. In the scanning fundus photography apparatus according to any one of claims 1 to 3, A scanning fundus photography apparatus, characterized in that a scanning angle of the light on the fundus in the first optical system is 40 degrees or more.

Images