JP7051041B2 - Wide-angle attachment and fundus photography device - Google Patents

Description

The present disclosure relates to a wide-angle attachment that widens the imaging range in the eye to be inspected, and an ophthalmologic imaging apparatus provided with the wide-angle attachment.

Conventionally, an ophthalmologic photographing apparatus capable of photographing an eye to be inspected by changing the shooting angle of view has been known. For example, the fundus photography apparatus disclosed in Patent Document 1 can widen the angle of view of the fundus image by attaching a wide-angle lens attachment.

Japanese Unexamined Patent Publication No. 2016-123467

However, in an optical system in which the captured light is focused on the pupil by a lens and guided to the fundus, a bright spot image due to surface reflection of the lens may be generated in the central portion of the fundus image obtained by photographing. In an optical system based on a lens system, the larger the angle of view is to be obtained, the larger the bright spot image is generated, which tends to hinder the observation / diagnosis of the fundus.

The present disclosure has been made in view of the problems of the prior art, and it is a technical subject to provide a wide-angle attachment and an ophthalmologic imaging apparatus capable of capturing a wide-angle fundus image while suppressing a bright spot image.

The wide-angle attachment according to the first aspect of the present disclosure is a wide-angle attachment that has a first mirror and a second mirror system and is attached to and detached from the photographing optical system. The photographing optical system includes a light receiving element and a light receiving element. The photographing optical system has an objective optical system arranged on an optical axis extending linearly toward the eye to be inspected, and further, when the wide-angle attachment is not attached, the photographing optical system is an emission of the objective optical system. By emitting the photographing light in a state where the first ejection pupil, which is a pupil, coincides with the anterior segment of the eye to be inspected, the fundus reflected light of the photographing light is received by the light receiving element, and the wide-angle attachment is the photographing optics. When mounted on the system, the first mirror is arranged on the optical axis and reflects the photographing light emitted toward the first ejection pupil in a direction intersecting the optical axis. The second mirror system includes a first light beam, which is a shooting light incident on the optical axis from the shooting optical system to the first mirror, and a second light beam, which is a shooting light incident from outside the optical axis. By reflecting both of the above, the first emission pupil is relayed to the second emission pupil, and further, the imaging via the second emission pupil by at least one of the first mirror and the second mirror system. The emission range of light is increased with respect to the emission range through the first emission pupil.

The fundus imaging device according to the second aspect of the present disclosure is a fundus imaging device including a photographing optical system and a wide-angle attachment attached to and detached from the photographing optical system, and the photographing optical system includes a light receiving element and a light receiving element. The photographing optical system has an objective optical system arranged on an optical axis extending linearly toward the eye to be inspected, and when the wide-angle attachment is not attached, the photographing optical system is an ejection pupil of the objective optical system. By emitting the photographing light in a state where the first ejection pupil, which is When it has a second mirror system and the wide-angle attachment is attached to the photographing optical system, the first mirror is arranged on the optical axis and is emitted toward the first ejection pupil. The photographed light is reflected in a direction intersecting the optical axis, and the second mirror system is a first light beam that is incident on the optical axis from the photographing optical system to the first mirror. By reflecting both and the second light beam which is the photographing light incident from the outside of the optical axis, the first ejection pupil is relayed to the second ejection pupil, and further, the first mirror and the second mirror system. By at least one of the above, the emission range of the photographed light through the second emission pupil is increased with respect to the emission range through the first emission pupil.

According to the present disclosure, it is possible to take a wide-angle fundus image while suppressing a bright spot image.

It is a figure which shows the appearance of the ophthalmologic imaging apparatus which concerns on Example. It is a figure which shows the appearance of the apparatus which attached the wide-angle attachment. It is a figure which showed the photographing optical system which concerns on Example. It is a figure which showed the optical structure of the wide-angle attachment which concerns on Example. It is a figure which shows the control system of SLO which concerns on Example.

"overview"
Hereinafter, the present disclosure will be described based on an embodiment. The fundus photography device according to the embodiment switches the angle of view of the fundus image taken by the fundus photography device by attaching / detaching the wide-angle attachment (see FIGS. 1 and 2). The fundus photography device can switch the shooting mode in conjunction with the attachment / detachment of the wide-angle attachment.

In the present embodiment, the fundus photography apparatus includes at least a photography optical system and a wide-angle attachment. In addition, the fundus photography device may have a control unit, an image processing unit, and a moving mechanism.

<Shooting optical system>
The photographing optical system includes at least a light receiving element and an objective optical system (see FIG. 3). The photographing optical system has an optical axis extending linearly toward the eye to be inspected (hereinafter referred to as "first optical axis"), and the objective optical system is arranged on the first optical axis. In the photographing optical system, the first exit pupil, which is the exit pupil of the objective optical system, emits the photographing light in a state of being aligned with the anterior eye portion of the eye to be inspected, so that the fundus reflected light of the photographing light is received by the light receiving element. do.

In the present embodiment, the frontal image of the fundus is acquired as the fundus image based on the signal from the light receiving element. The fundus image may be generated by processing the signal from the light receiving element by the image processing unit.

<Wide-angle attachment>
The wide-angle attachment is attached to and detached from the photographing optical system. For example, the device housing may be attached to or detached from the subject-side housing surface of the apparatus housing for accommodating the photographing optical system. The optical system of the wide-angle attachment may be a non-coaxial mirror system (mirror group) (see FIG. 4). The wide-angle attachment includes a first mirror and a second mirror system. By arranging the first mirror on the first optical axis in the photographing optical system, the first mirror reflects the photographed light emitted toward the first exit pupil in the direction intersecting the first optical axis. The second mirror system may have at least one mirror. The second mirror system relays the first exit pupil to the second exit pupil by further reflecting the photographing light reflected by the first mirror. More specifically, the photographing light (first light beam) incident on the first mirror from the photographing optical system along the first optical axis, and the photographing light (second light beam) incident from outside the first optical axis. The second mirror system reflects both of these, thereby relaying the exit pupil. As a result, the photographing light is irradiated to the predetermined range without omission.

Further, the wide-angle attachment increases the emission range of the photographing light through the second exit pupil with respect to the emission range through the first exit pupil. That is, the angle of view, which is the shooting range, is increased by attaching the wide-angle attachment. The effect of increasing the angle of view may be realized by only one of the first mirror and the second mirror system, or may be realized by both.

The first mirror may be a plane mirror or a curved mirror. When the first mirror is a curved mirror, the first mirror may cancel a part or all of the change in diopter due to the second mirror system (in other words, it may be reduced). The first mirror, which is a curved mirror, may be a spherical mirror. However, the present invention is not limited to this, and the mirror surface of the first mirror may be an aspherical surface or a free curved surface. The first mirror may be arranged so that the first exit pupil is formed on the mirror surface of the first mirror when the wide-angle attachment is attached to the photographing optical system. In this case, the area of the first mirror can be suppressed, and the mirror surface shape of the first mirror can be easily formed into a simpler shape such as a spherical mirror.

The second mirror system has at least one curved mirror. The mirror surface shape of the curved mirror may be, for example, an aspherical surface or a free curved surface. Unless otherwise specified, in the present embodiment, the "aspherical surface" refers to a curved surface composed of a locus obtained by rotating a curve around an axis of symmetry. The aspherical surface may be, for example, a quadric surface. In this case, the curved mirror of the second mirror system may be at least one of a parabolic mirror, a hyperboloid mirror, and an elliptical mirror, for example. Unless otherwise specified, the "quadric surface" in the present embodiment means a quadric surface having two focal points. The parabolic mirror has one focal point at infinity. The quadric surface is advantageous for good relay of the exit pupil. Further, the free curved surface may be an xy polynomial surface. The so-called asymmetric aspherical mirror is a kind of free curved mirror.

The curved surface mirror of the second mirror system may be an aspherical mirror or a free curved surface mirror having a base surface as a quadratic curved surface. In this case, the focal position of the aspherical mirror or the free curved mirror substantially coincides with the focal position of at least one of the quadric surface used as the base surface. Further, the positions of the surface vertices in the aspherical mirror or the free curved surface mirror may be substantially the same as the positions of the surface vertices in the base quadratic curved surface. In this case, the curved surface mirror of the second mirror system has a high-order curved surface shape to suppress the occurrence of aberration, and at the same time, it is possible to satisfactorily relay the exit pupil by utilizing the characteristics of the quadric surface. can.

Furthermore, even if the surface vertices of the aspherical component or free-form surface component added to the base surface are arranged at the intersection of the base surface and the optical axis (the trajectory of the light beam following the first optical axis in the wide-angle attachment). good. This facilitates optical design. For example, when the optimization design of the aspherical surface component or the free curved surface component is performed, the optical axis can be fixed.

Further, the second mirror system may have a second optical axis parallel to the optical axis and may form a second exit pupil on the second optical axis. It is desirable that the second optical axis is coaxial with the above-mentioned optical axis in the photographing optical system. In this case, before and after switching the angle of view, it is possible to take an image without changing the positional relationship in the vertical and horizontal directions between the eye to be inspected and the device.

In order to arrange the second optical axis coaxially with the optical axis in the photographing optical system, the second mirror system requires at least two mirrors. Specifically, a mirror for folding back the shooting light reflected by the first mirror toward the optical axis side of the shooting optical system (referred to as a “folded mirror” for convenience) and the shooting light reflected by the folded mirror are directed toward the eye to be inspected. The second mirror system may have a mirror that reflects and condenses light (referred to as a "condensing mirror" for convenience).

Compared to the case where the wide-angle attachment is not attached, the wide-angle attachment as described above is attached to the imaging optical system, and the imaging light is emitted with the anterior segment of the eye to be inspected aligned with the second exit pupil. , It becomes possible to take a wider angle of view of the fundus image. Further, in the present embodiment, since the wide-angle attachment is a mirror system, a bright spot image derived from the wide-angle attachment does not occur. Therefore, it is possible to satisfactorily observe the fundus by using the fundus image having a wide angle of view.

Further, by using a mirror surface shape having a more complicated shape such as an aspherical surface or a free curved surface having a term of the third order or higher for the mirror included in the wide-angle attachment, it becomes easy to form a wide-angle attachment having a short overall length. Therefore, the wide-angle attachment can be attached and detached in a smaller space.

<Mode switching>
The control unit may switch the shooting mode based on the attachment / detachment of the wide-angle attachment. The shooting mode means a shooting method defined by a combination of a shooting angle of view and a corresponding shooting condition. For example, the shooting mode may be switched between at least two modes, a standard angle of view mode and a wide angle mode. The control amount of each part, the condition for determining the operation of each part, and the like may be changed between the standard angle of view mode and the wide-angle mode. For example, at least one of light intensity and gain, diopter correction step, focus state target, fixative size and position, or other conditions may be modified.

The control unit may detect the mounting state of the wide-angle attachment (that is, whether or not it is mounted) and switch the shooting mode based on the detection result. The control unit may detect the mounting state based on, for example, a signal from a sensor provided in the device, or may detect it based on a predetermined operation input by the examiner.

<Distortion correction>
Since the wide-angle attachment is a non-coaxial mirror system, scan points (eg, pixel capture positions) on the fundus can be asymmetrically distributed in at least one direction. As a result, the fundus image taken with the wide-angle attachment attached may be distorted asymmetrically with respect to one direction of the fundus image. On the other hand, the ophthalmologic photographing apparatus may have a correction unit for correcting the asymmetrical distortion. As the correction amount, for example, one derived in advance from the imaging result of a Ronkey chart placed at the position of the retina may be used.

The distortion correction may be image processing for the captured fundus image, or signal processing for converting the signal from the light receiving element into the fundus image. Further, when the fundus photography device is a scanning type image pickup device, the distortion correction may be a control process of an optical scanner.

<Relationship between the movable range of the moving mechanism and the total length of the wide-angle attachment>
The moving mechanism supports the photographing optical system and moves the photographing optical system at least in the front-rear direction. The moving mechanism may move the photographing optical system in a direction other than the front-back direction. The moving mechanism may be one in which two or more mechanisms jointly move the photographing optical system.

Here, it is preferable that the total length of the wide-angle attachment is formed shorter than the movable range in the front-rear direction in the moving mechanism. In this case, by moving the photographing optical system away from the subject by the moving mechanism, the wide-angle attachment can be attached and detached without moving the subject's face. As described above, by using a mirror surface shape having a more complicated shape such as an aspherical surface or a free curved surface having a term of the third order or higher for the mirror included in the wide-angle attachment, it becomes easy to form a wide-angle attachment having a short overall length. Therefore, it is advantageous to shorten the total length as compared with the movable range in the front-rear direction in the moving mechanism.

"Example"
Hereinafter, the scanning laser ophthalmoscope 1 and the wide-angle attachment 100, which are examples of the present disclosure, will be described with reference to FIGS. 1 to 5. The scanning laser ophthalmoscope 1 is a kind of ophthalmologic photographing apparatus that captures a front image of the fundus. Hereinafter, the scanning laser ophthalmoscope 1 is abbreviated as SLO (Scanning Laser Ophthalmoscope) 1. Further, in this embodiment, the SLO1 has a wide-angle attachment 100 (see FIG. 2), and the main part of the SLO1 excluding the wide-angle attachment 100 is referred to as a device main body of the SLO1.

The SLO1 scans the laser beam (photographed light in this embodiment) on the fundus and receives the reflected light from the fundus of the laser beam to acquire a front image of the fundus. The SLO1 may be a device integrated with other ophthalmic devices such as an optical coherence tomography (OCT) and a perimeter. In this embodiment, SLO1 acquires a fundus image by two-dimensionally scanning the laser beam focused on the spot on the observation surface based on the operation of the scanning unit (optical scanner). However, the present invention is not limited to this, and the SLO1 may be a so-called line scan type apparatus. In this case, a linear luminous flux is scanned on the observation surface.

In SLO1 of this embodiment, the angle of view is switched to two predetermined values by attaching / detaching the wide-angle attachment 100. Here, the narrower angle of view is referred to as a "first angle of view", and the wider angle of view is referred to as a "second angle of view". For example, the first angle of view may be about 45 ° to 60 °, and the second angle of view may be about 90 ° to 150 °. In this embodiment, the wide-angle attachment 100 is not attached, so that the first angle of view is set, and the wide-angle attachment 100 is attached, so that the second angle of view is set.

<Appearance configuration>
As shown in FIGS. 1 and 2, in the present embodiment, the apparatus main body includes a photographing unit 4, an alignment mechanism 5, a base 6, a face support unit 7, and a sensor. An optical system for photographing the eye E to be inspected is stored in the photographing unit 4. This optical system will be described later with reference to FIG.

As shown in FIGS. 2 and 4, the wide-angle attachment 100 is configured to be detachably attached to the housing 4a of the main body of the apparatus. More specifically, the wide-angle attachment 100 is attached to and detached from the housing surface on the subject side. The SLO1 is capable of fundus photography in both the attached state and the non-attached state of the wide-angle attachment 100. The wide-angle attachment 100 widens the angle of view of the fundus image obtained by the apparatus main body by being attached to the housing 4a.

The alignment mechanism 5 (“movement mechanism” in this embodiment) is used to align the device with respect to the eye E to be inspected. In this embodiment, the alignment mechanism 5 moves the photographing unit 4 three-dimensionally with respect to the base 6. The photographing unit 4 may be movable in each of the Y direction (vertical direction), the X direction (horizontal direction :), and the Z direction (front-back direction). In this embodiment, the movable range of the photographing unit 4 by the alignment mechanism 5 is about 20 cm in the Z direction. This is a standard range for stationary ophthalmic devices in general.

As shown in FIGS. 1 and 2, the face support unit 7 supports the face of the subject with the eye E to be inspected facing the photographing unit 4. In this embodiment, the face support unit 7 is fixed to the base 6.

Further, as a detection means for detecting the attachment of the wide-angle attachment 100, a sensor (not shown) may be provided. The sensor outputs a detection signal according to the mounting state of the wide-angle attachment 100. For example, even if the sensor continuously outputs electric signals having different voltage values depending on whether the wide-angle attachment 100 is attached to the main body of the device or the wide-angle attachment 100 is not attached to the main body of the device. good. The sensor can be appropriately selected from various contact sensors and non-contact sensors.

<Optical configuration>
The optical system provided in SLO1 will be described with reference to FIGS. 3 and 4. As shown in FIG. 3, the SLO 1 includes an irradiation optical system 10 and a light receiving optical system 20 (collectively referred to as “photographing optical system”). SLO1 captures a fundus image using these optical systems 10 and 20.

The irradiation optical system 10 includes at least a scanning unit 16 and an objective lens system 17. Further, as shown in FIG. 3, the irradiation optical system 10 further includes a laser light source 11, a collimating lens 12, a perforated mirror 13, and a lens 14 (a part of the diopter adjusting unit 40 in this embodiment). And may have a lens 15.

The laser light source 11 is a light source of the irradiation optical system 10. In this embodiment, the laser light from the laser light source 11 is used as the illumination light. The laser light source 11 may be formed including, for example, a laser diode (LD), a super luminescent diode (SLD), or the like.

In this embodiment, the laser beam is guided to the fundus Er in the path of the light beam shown in FIG. That is, the laser light from the laser light source 11 passes through the opening formed in the perforated mirror 13 via the collimating lens 12, passes through the lens 14 and the lens 15, and then heads toward the scanning unit 16. The laser light reflected by the scanning unit 16 passes through the objective lens system 17 and then irradiates the fundus Er of the eye E to be inspected. As a result, the laser beam is reflected and scattered by the fundus Er. These lights (that is, reflected / scattered light) are emitted from the pupil as return light.

The scanning unit 16 (also referred to as an “optical scanner”) is a unit for scanning a laser beam emitted from a light source (laser light source 11) on the fundus. In the following description, unless otherwise specified, the scanning unit 16 includes two optical scanners in which the scanning directions of the laser light are different from each other. That is, the scanning unit 16 includes an optical scanner 16a for main scanning (for example, scanning in the X direction) and an optical scanner 16b for sub-scanning (for example, scanning in the Y direction). As an example, the optical scanner 16a for the main scan may be a resonant scanner, and the optical scanner 16b for the sub scan may be a galvano mirror. However, other optical scanners may be applied to the optical scanners 16a and 16b. For example, for each optical scanner 16a, 16b, in addition to other reflection mirrors (galvano mirror, polygon mirror, resonant scanner, MEMS, etc.), an acoustic optical element (AOM) that changes the traveling (deflection) direction of light, etc. May be applied.

The objective lens system 17 is an objective optical system of SLO1. The objective lens system 17 is used to guide the laser beam scanned by the scanning unit 16 to the fundus Er. The objective lens system 17 forms a turning point P at the position of the exit pupil (first exit pupil) of the objective lens system 17. Specifically, the position of the turning point P is on the optical axis L1 of the irradiation optical system 10 and is optically coupled to the scanning unit 16 with respect to the objective lens system 17. At the turning point P, the laser beam that has passed through the scanning unit 16 is swirled.

In the present disclosure, the term "conjugate" is not necessarily limited to a perfect conjugate relationship, but includes "substantially conjugate". That is, the case where the fundus image is displaced from the perfect conjugate position within the permissible range in relation to the purpose of use (for example, observation, analysis, etc.) is also included in the "conjugation" in the present disclosure.

The laser beam that has passed through the scanning unit 16 passes through the objective lens system 17 and is irradiated to the fundus Er in the swirl point P. By swirling the laser beam around the swirl point P, the laser beam is two-dimensionally scanned on the fundus Er. The laser beam applied to the fundus Er is reflected at the condensing position (for example, the surface of the retina). The fundus reflected light is emitted from the pupil as parallel light.

Next, the light receiving optical system 20 will be described. The light receiving optical system 20 has one or more light receiving elements. For example, as shown in FIG. 3, the light receiving element 29 may be provided. In this case, the fundus reflected light generated by the laser beam emitted by the irradiation optical system 10 is received by the light receiving element 29.

As shown in FIG. 3, in the light receiving optical system 20 in this embodiment, each member arranged from the objective lens system 17 to the perforated mirror 13 may be shared with the irradiation optical system 10. In this case, the light from the fundus is guided back to the perforated mirror 13 in the optical path of the irradiation optical system 10. The perforated mirror 13 receives the light received from the fundus while removing at least a part of the noise light reflected by the corneal membrane of the eye to be inspected and the optical system inside the device (for example, the lens surface of the objective lens system). Lead to 20 independent optical paths. The optical path branching member for branching the irradiation optical system 10 and the light receiving optical system 20 is not limited to the perforated mirror 13, and other beam splitters may be used.

The light receiving optical system 20 of this embodiment has a lens 21 and a pinhole plate 23 in the reflected optical path of the perforated mirror 13. The pinhole plate 23 is arranged on the fundus conjugate surface and functions as a confocal diaphragm in SLO1. That is, when the diopter is properly corrected by the diopter adjusting unit 40, the light from the fundus Er that has passed through the lens 21 is focused at the opening of the pinhole plate 23. The pinhole plate 23 removes light from a position other than the condensing point (or focal plane) of the fundus Er, and the rest (light from the condensing point) is guided to the light receiving element 29.

<Wide-angle attachment>
Next, the optical configuration of the wide-angle attachment 100 will be described with reference to FIG. The wide-angle attachment 100 is mounted between the objective lens system 17 and the eye E to be inspected, so that the "second angle of view" is set.

As shown in FIG. 4, in this embodiment, the wide-angle attachment 100 has four mirrors 110, 121, 122, 123. Each mirror 110, 121, 122, 123 may be a non-coaxial mirror.

The mirror 110 arranged closest to the objective optical system 17 is the “first mirror” in this embodiment. In a state where the wide-angle attachment 100 is attached to the apparatus main body (to the photographing optical system), the mirror 110 is arranged so that the turning point P formed by the objective optical system 17 of the apparatus main body coincides with the mirror surface. That is, the mirror 110 is arranged so as to coincide with the exit pupil of the objective optical system 17. At this time, the mirror 110 is arranged so that the optical axis of the mirror 110 intersects the optical axis L1 of the photographing optical system. As a result, the laser beam emitted toward the exit pupil (exit pupil) of the objective optical system is reflected by the mirror 110 in the direction intersecting the optical axis L1.

In this embodiment, the mirror 110 is a spherical mirror, and the convex surface is a reflecting surface. The mirror 110 may have the power to cancel the change in diopter caused by the other three mirrors 121, 122, 123. In other words, the curvature of the mirror 110 is set according to the power of the other three mirrors 121, 122, 123. When the mirror 110 is an aspherical mirror, a free curved mirror, or the like and has a different curvature depending on the reflection position of the light beam, the curvature at each reflection position is the other three mirrors 121, 122. , It is desirable that it is set in correspondence with the power that cancels the change in diopter due to 123.

In this embodiment, the mirror surfaces of the remaining three mirrors 121, 122, and 123 are all free curved surfaces based on the quadric surface. The three mirrors 121, 122, and 123 are the "second mirror system" in this embodiment. The three mirrors 121, 122, and 123 further reflect the photographing light reflected by the mirrors, whereby the first exit pupil is relayed to the second exit pupil. In this embodiment, the photographing light reflected by the mirror 110 in the direction intersecting the optical axis L1 is folded back toward the optical axis L1 by the two mirrors 121 and 122. The folded shooting light is further reflected by the mirror 123. As a result, light rays having different angles when incident on the first exit pupil intersect at one point on the reflection side of the mirror 123. The one point is the second exit pupil, and in SLO1, the position is the second turning point Q. In the state where the wide-angle attachment 100 is attached, imaging is performed with the anterior eye portion located at the second turning point Q. The wide-angle attachment 100 of this embodiment has the central axis of the reflected light in the mirror 123 as the second optical axis L2, and each mirror so that the second optical axis L2 is coaxial with the first optical axis L1. 110, 121, 122, 123 are arranged. Therefore, before and after attaching / detaching the wide-angle attachment 100, there is no need to change the positional relationship between the eye to be inspected and the device in the vertical / horizontal direction.

Further, the three mirrors 121, 122, and 123 further reflect the photographing light reflected by the mirror 110, so that the emission range of the photographing light through the second exit pupil is transmitted through the first exit pupil. Increased with respect to the exit range. That is, in this embodiment, the angle of view is increased by three of the four mirrors 110, 121, 122, 123 corresponding to the second mirror system.

In the example of FIG. 4, the mirror 121 is formed as a concave mirror, the mirror 122 is formed as a convex mirror, and the mirror 123 is formed as a concave mirror. However, the present invention is not limited to this, and whether each of them has a concave surface or a convex surface may be appropriately changed. Further, in this embodiment, all of the three mirrors 121, 122, and 123 are free curved mirrors, but it is conceivable that the number of free curved mirrors is two or less. For example, each of the mirrors 121 and 123 may be an ellipsoidal mirror, and only the mirror 122 may be a free curved mirror.

In this embodiment, an optical system having three mirrors 121, 122, and 123 has been described as the second mirror system, but the present invention is not limited to this. For example, when the second optical axis L2 is coaxial with the first optical axis L1, at least two mirrors are sufficient for the second mirror system, and the second optical axis L2 is not limited to the coaxial and is the first optical axis L1. As long as they are parallel, at least one mirror is sufficient for the second mirror system. Of course, the optical system of the wide-angle attachment 100 may be formed by four or more mirrors.

When the wide-angle attachment 100 as described above is attached to the main body of the device, the wide-angle attachment 100 is a mirror system and does not generate a luminous flux returning to the light receiving element 29 side without passing through the second exit pupil. It is possible to take a fundus image of the second angle of view without producing a reflected image. Further, a light ray that follows the first optical axis L1 and is incident on the first entrance pupil (that is, the turning point P) and is incident on the first entrance pupil (that is, the turning point P) from outside the axis of the first optical axis L1. Both the light beam and the light beam are reflected by the four mirrors 110, 121, 122, 123 and guided to the fundus. That is, the photographing light can be irradiated to the range corresponding to the second angle of view on the fundus without omission. As a result, the fundus image of the second angle of view without the reflection image derived from the wide-angle attachment 100 can be taken once.

Further, as a result of using the free curved mirror as the three mirrors 121, 122, 123 (second mirror system) as described above, the entire length of the wide-angle attachment 100 is measured in the Z direction in the alignment mechanism 5 in this embodiment. It became possible to shorten the movable range of. As an example, while the movable range of the alignment mechanism 5 in the Z direction is 200 mm, the total length of the wide-angle attachment 100 can be formed with a total length less than that (note that, as a design solution, the total length of the wide-angle attachment 100 can be formed. It can be about 120 mm). As a result, by retracting the device main body from the subject, a space for attaching / detaching the wide-angle attachment 100 is secured between the subject and the device main body. That is, the wide-angle attachment 100 can be attached / detached while the subject's face is supported by the face support unit 7.
<Control system configuration>
Next, the control system of SLO1 will be described with reference to FIG. Each unit of SLO1 is controlled by the control unit 70. The control unit 70 is a processing device (processor) having an electronic circuit that performs control processing of each unit of SLO1 and arithmetic processing. The control unit 70 is realized by a CPU (Central Processing Unit), a memory, or the like. The control unit 70 is electrically connected to the storage unit 71 via a bus or the like. Further, the control unit 70 is electrically connected to each unit such as the laser light source 11, the light receiving element 29, the scanning unit 16, the input interface 75, and the monitor 80.

Various control programs, fixed data, and the like are stored in the storage unit 71. Further, temporary data or the like may be stored in the storage unit 71. The image obtained by SLO1 may be stored in the storage unit 71. However, the present invention is not limited to this, and the image obtained by SLO1 may be stored in an external storage device (for example, a storage device connected to the control unit 70 by LAN and WAN). In this embodiment, the control unit 70 also serves as an image processing unit (image forming unit), a mode switching unit, and a correction unit.

As an image processing unit, the control unit 70 forms a fundus image based on, for example, a light receiving signal output from the light receiving element 29. More specifically, the control unit 70 forms a fundus image in synchronization with the optical scanning by the scanning unit 16. For example, the control unit 70 receives at least one frame (in other words, one) of the fundus image (light receiving element) each time the optical scanner 16b for sub-scanning reciprocates n times (n is an integer of 1 or more). Form (every time). In the following, unless otherwise specified, for convenience, one frame of fundus image is formed every time the optical scanner 16b for sub-scanning makes one round trip.

The control unit 70 may display the fundus images of a plurality of frames sequentially formed based on the operation of the device as described above on the monitor 80 in chronological order as observation images. The observation image is a moving image consisting of a fundus image acquired in substantially real time. Further, the control unit 70 captures (captures) a part of the plurality of fundus images sequentially formed as a captured image (captured image). At that time, the captured image is stored in the storage medium. The storage medium in which the captured image is stored may be a non-volatile storage medium (for example, a hard disk, a flash memory, etc.). In this embodiment, for example, a fundus image formed at a predetermined timing (or period) after the output of a trigger signal (for example, a release operation signal or the like) is captured.

The input interface 75 is an operation unit that accepts the operation of the examiner. For example, a touch panel, a mouse, a keyboard, and the like may be used as the input interface 75. Such an input interface 75 may be a device separate from the SLO1. The control unit 70 controls each of the above members based on the operation signal output from the input interface 75 (operation unit). For example, an operation for selecting a shooting mode, an operation for releasing, or the like may be input to the input interface 75.

In this embodiment, the control unit 70 selectively sets the shooting mode from the standard angle of view mode and the wide angle mode. In this embodiment, the photographing mode is switched based on the operation input related to the mode switching by the examiner. However, the present invention is not limited to this, and the attachment / detachment state of the wide-angle attachment 100 may be detected and set based on the detection result.

Of the two shooting modes, the distortion correction processing is executed only in the wide-angle shooting mode. In this embodiment, as shown in FIG. 4, since the wide-angle attachment 100 has an optical system that is asymmetric in the vertical direction (Y direction), it causes asymmetric distortion in the vertical direction. Therefore, the distortion is corrected by a correction process. In this embodiment, distortion correction is performed by image processing. That is, the correction process is performed on the photographed fundus image of the second angle of view so that the density of the scan points in the vertical direction approaches the interval in the real space.

Further, the control unit 70 may automatically switch to the wide-angle mode after the shooting in the standard angle of view mode is completed. At that time, the control unit 70 may drive and control the alignment mechanism 5 to automatically move the imaging unit 4 away from the eye E to be inspected. As a result, the wide-angle attachment 100 can be smoothly attached. In addition, it is possible to prevent shooting under the shooting conditions of the wide-angle mode before the wide-angle attachment 100 is attached.

<Modification example>
Although the above description has been made based on the embodiment, the present disclosure is not limited to the above embodiment, and various modifications are possible.

For example, in the above embodiment, the wide-angle attachment is separate from the main body of the fundus photography device, and the examiner manually attaches and detaches the attachment to and from the main body of the device. However, the present invention is not limited to this, and the wide-angle attachment may be provided integrally with the main body of the fundus photography device, and the angle of view switching mechanism provided in the fundus photography device captures the wide-angle attachment. The wide-angle attachment may be attached or detached by inserting or removing it between the system and the eye of the eye to be inspected.

Further, in the above embodiment, the second mirror system of the wide-angle attachment is arranged on the upper side of the first optical axis, but the present invention is not limited to this. For example, the second mirror system may be arranged below the first optical axis. In this case, the examiner can easily see the subject. In addition, the operation of opening the upper eyelid becomes easy.

4 Wide-angle attachment 10 Floodlight optical system 20 Light receiving optical system 110 Mirror 121 to 123 Mirror L1 Optical axis

Claims (8)

A wide-angle attachment that has a first mirror and a second mirror system and is attached to and detached from the photographing optical system.
The photographing optical system is
It has a light receiving element and an objective optical system arranged on an optical axis extending in a straight line toward the eye to be inspected.
Further, when the wide-angle attachment is not attached, the photographing optical system emits the photographing light in a state where the first exit pupil, which is the exit pupil of the objective optical system, coincides with the anterior segment of the eye to be inspected. Thereby, the fundus reflected light of the photographing light is received by the light receiving element, and the light is received by the light receiving element.
When the wide-angle attachment is attached to the photographing optical system,
The first mirror is arranged on the optical axis and reflects the photographing light emitted toward the first exit pupil in a direction intersecting the optical axis.
The second mirror system includes a first light beam, which is a shooting light incident on the optical axis from the shooting optical system to the first mirror, and a second light beam, which is a shooting light incident from outside the optical axis. By reflecting both of them, the first exit pupil is relayed to the second exit pupil.
Further, at least one of the first mirror and the second mirror system increases the emission range of the photographing light through the second exit pupil with respect to the emission range through the first exit pupil. attachment. At least one mirror included in the second mirror system is a curved mirror having a quadratic curved surface having two focal points or a high-order aspherical surface or a free curved surface based on the quadratic curved surface as a mirror surface. , The wide-angle attachment according to claim 1. The wide-angle attachment according to claim 1 or 2, wherein the first mirror is a curved mirror that reduces a change in diopter due to the second mirror system. The wide-angle attachment according to any one of claims 1 to 3, wherein the second mirror system has a second optical axis parallel to the optical axis and forms the second exit pupil on the second optical axis. .. The second mirror system is
It has at least a folded mirror for folding back the imaged light reflected by the first mirror toward the optical axis side and a condensing mirror for reflecting and condensing the imaged light reflected by the folded mirror toward the eye to be inspected. The wide-angle attachment according to claim 4, wherein the second optical axis is arranged coaxially with the optical axis. A fundus photography device including a photographic optical system and a wide-angle attachment attached to and detached from the photographic optical system.
The photographing optical system is
It has a light receiving element and an objective optical system arranged on an optical axis extending in a straight line toward the eye to be inspected.
Further, when the wide-angle attachment is not attached, the photographing optical system emits the photographing light in a state where the first exit pupil, which is the exit pupil of the objective optical system, coincides with the anterior segment of the eye to be inspected. Thereby, the fundus reflected light of the photographing light is received by the light receiving element, and the light is received by the light receiving element.
Wide-angle attachment
It has a first mirror and a second mirror system.
When the wide-angle attachment is attached to the photographing optical system,
The first mirror is arranged on the optical axis and reflects the photographing light emitted toward the first exit pupil in a direction intersecting the optical axis.
The second mirror system includes a first light beam, which is a shooting light incident on the optical axis from the shooting optical system to the first mirror, and a second light beam, which is a shooting light incident from outside the optical axis. By reflecting both of the above, the first exit pupil is relayed to the second exit pupil, and further, the imaging via the second exit pupil by at least one of the first mirror and the second mirror system. A fundus imaging device that increases the emission range of light with respect to the emission range through the first exit pupil. The fundus photography apparatus according to claim 6, further comprising a distortion correction means for correcting asymmetric distortion in one direction in a fundus image taken with the wide-angle attachment attached. It has a moving mechanism that supports the photographing optical system and moves the photographing optical system at least in the front-rear direction.
The fundus photography apparatus according to claim 6, wherein the total length of the wide-angle attachment is equal to or less than the movement range in the front-rear direction in the movement mechanism.

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