JP2022185861A - Scanning fundus camera - Google Patents

Abstract

A scanning-type fundus imaging apparatus capable of suitably acquiring a fundus image of an eye to be inspected is a technical problem.
[Solution]
The scanning fundus imaging apparatus is a first optical system having a confocal aperture, which scans and irradiates light onto the fundus and receives light returned from the fundus through the confocal aperture. a second optical system different from the first optical system, an optical path coupling mirror that couples the first optical path of the first optical system and the second optical path of the second optical system, and a protective member that protects the optical path coupling mirror; , the first fundus conjugate position of the first optical system exists in the common optical path on the side of the subject's eye in the first optical path and the second optical path, and the separated light, which is a part of the light from the first optical system, passes through the optical path coupling mirror A third optical path of the separated light is formed by traveling in a direction different from the common optical path, and a second fundus conjugate position mirror-symmetrical to the first fundus conjugate position with respect to the optical path coupling mirror is formed on the third optical path. , the wall of the protective member is spaced apart from the second fundus conjugate position.
[Selection drawing] Fig. 4

Description

The present disclosure relates to a scanning fundus imaging apparatus that photographs the fundus of an eye to be examined.

A scanning light ophthalmoscope (SLO) that obtains a fundus image of an eye to be inspected by scanning light is known. This apparatus 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 apparatus of Patent Document 1 includes an SLO optical system and an OCT (Optical Coherence Tomography) optical system.

JP 2019-134896 A

In the apparatus described above, the optical path of the SLO optical system and the optical path of the other optical system are coupled by the optical path coupling member. In such a configuration, the inventors have found that part of the light from the SLO optical system may be guided in an unintended direction by the optical path coupling member and appear as artifacts on the fundus image.

A technical problem of the present disclosure is to provide a scanning-type fundus imaging apparatus capable of suitably acquiring a fundus image of a subject's eye in view of the above-described conventional technology.

A scanning fundus imaging apparatus for photographing the fundus of an eye to be inspected is a first optical system having a confocal aperture arranged at a position conjugate with the fundus, and scans light to the fundus through an objective lens. A first optical system for capturing a fundus image of the subject's eye by irradiating and receiving the return light of the light from the fundus through the confocal aperture, which is different from the first optical system a second optical system, an optical path coupling mirror that couples a first optical path of the first optical system, and a second optical path of the second optical system; and a protective member that protects at least the optical path coupling mirror. , the first fundus conjugate position of the first optical system exists at least in a common optical path on the subject's eye side in the first optical path and the second optical path, and is part of the light from the first optical system. A third optical path of the separated light is formed by the light traveling in a direction different from the common optical path by the optical path coupling mirror, and the first fundus conjugate position with respect to the optical path coupling mirror is formed on the third optical path. A second fundus conjugate position mirror-symmetrical to the second fundus conjugate position is formed, and the wall portion of the protective member is spaced apart from the second fundus conjugate position.

1 is an external view of a scanning fundus imaging device; FIG. It is a figure for demonstrating an imaging optical system. FIG. 4 is a diagram for explaining the relationship between a diopter correction amount and a fundus conjugate position; It is a figure explaining arrangement|positioning of the wall part of an imaging|photography part. 2 is a block diagram showing a control system of the scanning fundus imaging apparatus; FIG. FIG. 4 is a diagram for explaining the relationship between the angle of view for photographing an eye to be inspected and the wall portion of the photographing section;

[Overview]
An embodiment of a scanning fundus imaging apparatus according to the present disclosure will be described with reference to the drawings. The items classified in <> below can be used independently or in conjunction with each other. It should be noted that the term “conjugated” in the present embodiment is not necessarily limited to a perfect conjugated relationship, but includes “substantially conjugated”. That is, the term "conjugated" in this embodiment also includes the case where the parts are displaced from the perfectly conjugated position within the range allowed in relation to the technical significance of each part.

A scanning fundus imaging device (for example, a scanning fundus imaging device 1) of the present embodiment is a device that photographs the fundus of an eye to be examined. The scanning fundus imaging device may be an SLO device having a first optical system (SLO optical system), which will be described later, for scanning the fundus of the subject's eye with light. The scanning fundus imaging device may be a composite device in which the SLO device and other devices are combined. As an example, it may be a device combined with at least one of an optical coherence tomography device, a therapeutic laser device, and the like.

For example, a scanning fundus imaging apparatus includes a first optical system for capturing a fundus image of an eye to be examined. For example, a scanning fundus imaging device includes a second optical system different from the first optical system. For example, a scanning fundus imaging apparatus includes an optical path coupling mirror that couples the first optical path of the first optical system and the second optical path of the second optical system. For example, a scanning fundus imaging device includes a protection member that protects at least the optical path coupling mirror.

<First 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 (for example, the SLO optical system 500) scans and irradiates the light to the fundus through the objective lens, and receives the return light of the measurement light from the fundus through the confocal aperture. , to take a fundus image of the eye to be examined. That is, for example, the first optical system may be a confocal optical system that arranges a confocal aperture at a fundus conjugate position, or may capture a confocal front image of the fundus.

For example, the first fundus conjugate position of the first optical system exists at least in the 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 exists at least in the common optical path on the subject's eye side. In addition, such a first fundus conjugate position may be configured to be located between the objective lens and the optical path coupling mirror.

The first optical system includes a light irradiation unit (e.g., light source 56) that irradiates the fundus of the eye to be inspected with light, a scanning unit (e.g., scanning unit 52) that scans the fundus with light from the light irradiation unit, and the fundus. A confocal aperture (for example, confocal aperture 58) arranged at a conjugate position, a light receiving section (for example, light receiving element 59) for receiving light returned from the fundus, and the like may be provided. For example, the light irradiation section may irradiate laser light. Note that the light irradiation unit may be configured to irradiate light different from laser light. For example, the light receiving section may be a point sensor that detects the intensity of received light. For example, the light receiving section may be a one-dimensional light receiving element, a two-dimensional light receiving element, or the like.

For example, the first optical system may be configured such that a wider area of the fundus can be photographed by scanning light over the fundus. For example, the scanning unit may be configured so that the scanning angle of view of light on the fundus is 40 degrees or more. For example, the scanning unit may be a reflective mirror (eg, a galvanomirror, a polygon mirror, a resonant scanner, etc.). Further, for example, the scanning unit may be an acousto-optic element that changes the traveling direction of light.

The first optical system may include a dioptric correction means (for example, dioptric correction unit 53) capable of correcting diopter of the subject's eye in the first movement range of the first fundus conjugate position. The diopter correcting means may correct the diopter of the first optical system according to the refractive error of the eye to be examined. The diopter correction means may be configured to correct the diopter by moving the lens along the optical axis. For example, in this case, the dioptric power correction means may include a focusing lens (for example, focusing lens 53a) and a driving section (for example, driving section 53b) for moving the focusing lens. Further, the diopter correcting means may be configured to correct the diopter by inserting and removing the lens on the optical axis. Further, the dioptric power may be corrected by changing the refractive index of the dioptric correction section means and the varifocal lens.

In this embodiment, the diopter correction means may be configured to appropriately correct the diopter even when the eye to be examined has a large refractive error. For example, it may be possible to correct dioptric power for refractive errors of -10D or less and +10D or more, which are considered high diopter eyes. As an example, the diopter correction amount may be adjusted so as to be compatible with at least -15D.

<Control means>
The scanning fundus imaging apparatus of the present embodiment may include control means (for example, control section 71) for controlling the dioptric power correction means. The control means controls the diopter correction means and adjusts the diopter correction amount according to the diopter of the subject's eye. For example, the control means adjusts the diopter correction amount by driving a drive unit for moving the lens along the optical axis, or a drive unit for inserting/removing the lens on the optical axis. good too. Further, for example, the control means may adjust the diopter correction amount by controlling the current value applied to the varifocal lens.

<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 (such as 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 segment imaging optical system (for example, the anterior segment imaging optical system 200) that images the anterior segment of the subject's eye. Of course, the OCT optical system and the anterior segment imaging optical system are examples of the second optical system, and are not limited to these.

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

<Protective material>
For example, the protective member is provided to protect the optical path coupling mirror from dust, scratches, and the like. For example, the protective member may be a housing (for example, the imaging unit 2) that houses each optical system. Further, for example, the protective member may be a cover that accommodates at least the optical path coupling mirror separately from the housing.

<Arrangement of First Optical System and 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 arranged on either the reflection side or the transmission side of the optical path coupling mirror. For example, the independent optical path of the first optical path may be arranged on the reflection side of the optical path coupling mirror. In this case, the independent optical path of the second optical path may be arranged on the transmission side of the optical path coupling mirror. Also, for example, the independent optical path of the first optical path may be arranged on the transmission side of the optical path coupling mirror. In this case, the independent optical path of the second optical path may be arranged on the reflection side of the optical path coupling mirror. When the independent optical path of the first optical path is arranged on the transmission side of the optical path coupling mirror, the direction of light reflection by the scanning unit and the scanning direction of the fundus can be easily matched in the first optical system. Complication of the optical system can be suppressed.

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 coupling mirror, the reflection side of the optical path coupling mirror where the independent optical path of the second optical system is arranged is the optical path coupling mirror. It may be any of upper, lower, right and left sides. When the independent optical path of the second optical system is provided below the optical path coupling mirror, the second optical system is arranged below the first optical system. Therefore, the optical member is not positioned higher than the eye to be inspected, and when the eye to be inspected and the optical axis of each optical system are aligned, the apparatus is prevented from protruding above the eye to be inspected. The operator can easily perform eyelid-opening work and the like.

An optical member may be arranged between the objective lens and the optical path coupling mirror 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. For example, an optical path coupling mirror may be arranged for coupling optical paths of a third optical system different from the first optical system and the second optical system. Of course, a member different from the optical path coupling mirror may be arranged. Further, 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, no optical member may be arranged between the objective lens and the optical path coupling mirror. In this case, an optical path coupling mirror may be arranged near the objective lens, and the light from the first optical system may be guided to the objective lens without an optical member after passing through the optical path coupling mirror.

<Relationship between protective member and fundus conjugate position>
For example, the separated light, which is part of the light in the first optical system, is shared by an optical path coupling mirror that couples the independent optical path of the first optical path in the first optical system and the independent optical path of the second optical path in the second optical system. Unintentionally traveling in a direction different from the optical path. For example, when the independent optical path of the first optical path in the first optical system is arranged on the reflection side of the optical path coupling mirror, part of the light in the first optical system (separated light) is transmitted without being reflected by the optical path coupling mirror. As transmitted light, it travels in a direction different from the common optical path. Further, for example, when the independent optical path of the first optical path in the first optical system is arranged on the transmission side of the optical path coupling mirror, part of the light (separated light) in the first optical system does not pass through the optical path coupling mirror. As a reflected light reflected by , it travels in a direction different from the common optical path. This forms a third optical path for the separated light.

A second fundus conjugate position mirror-symmetrical to the first fundus conjugate position with respect to the optical path coupling mirror is formed on the third optical path of the separated light. 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, as the subject's eye has greater diopter on the minus diopter side, the first fundus conjugate position is located farther away from the optical path coupling mirror on the first optical path. The position also exists at a position away from the optical path coupling mirror on the second optical path. That is, there are 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 mirror-symmetrical to the first movement range. do.

For example, such separated light travels toward the walls of the protective member and is reflected by the walls of the protective member. For example, in the first optical system, the reflected light of the separated light reflected by the wall portion is blocked by the confocal aperture and thus does not reach the light receiving portion. 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 section without being blocked by the confocal aperture.

For example, when the diopter correction means corrects the diopter and the first fundus conjugate position with respect to the objective lens and the confocal aperture are adjusted to have a conjugate relationship, the second fundus that exists in mirror symmetry with the first fundus conjugate position The conjugate position also has a conjugate relationship with the confocal aperture. In this case, if the wall portion of the protective member and the second fundus conjugate position match, the reflected light beams reflected by the wall portion pass through the confocal aperture and reach the light receiving portion. There arises a problem that the wall of the eye appears as an artifact on the fundus image.

In this embodiment, the wall portion of the protective member is arranged at a distance from the second fundus conjugate position so that the wall portion and the second fundus conjugate position do not coincide with each other. Thereby, for example, even if the second fundus conjugate position and the confocal aperture are adjusted to have a conjugate relationship, it is possible to obtain a good fundus image in which reflection of the protective member is suppressed. In addition, in the present embodiment, in the case of adopting a configuration capable of coping with a wide range of diopter of the subject's eye, the wall portion of the protective member can be arranged at a distance from the diopter correction range of the second fundus conjugate position. important. According to this, regardless of the diopter of the subject's eye, it is possible to obtain a good fundus image in which reflection of the protective member is suppressed.

The independent optical path in the first optical path of the first optical system is arranged on the transmission side and confocal aperture side of the optical path coupling mirror, and the independent optical path in the second optical path of the second optical system is arranged on the reflection side and below the optical path coupling mirror. , the separated light in the first optical system is reflected toward the upper side opposite to the independent optical path of the second optical path with respect to the optical path coupling mirror, so that the third optical path and the second fundus conjugate form a position. At this time, by arranging the wall portion of the protection member on the side of the optical path coupling mirror at a distance from the second fundus conjugate position (second movement range of the second fundus conjugate position), it is possible to suppress reflection of the protection member. .

[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. FIG. As shown in FIG. 1, in this embodiment, the scanning fundus imaging apparatus 1 includes a base 101, a moving table 102, an operation unit 8, a monitor 73, a drive unit 5, a face support unit 110, an imaging unit 2, a control unit 71, etc.

The operation unit 8 receives signals for operating the imaging unit 2 . For example, when the operation unit 8 is tilted, a movement signal is input to move the movable table 102 in at least one of the left-right direction (X direction) and the front-back direction (Z direction) with respect to the base 101. . Further, for example, when a knob (not shown) of the operation unit 8 is rotated, a movement signal is input for moving the photographing unit 2 in the vertical direction (Y direction) with respect to the base 101 .

The monitor 73 displays a front image of the subject's eye E, OCT data, and the like on the screen. Also, the monitor 73 functions as a touch panel that also serves as the operation unit 8 . In other words, a movement signal for moving the photographing section 2 is also input by operating the monitor 73 .

The drive unit 5 moves the photographing unit 2 in the left-right direction, the up-down direction, and the front-rear direction. For example, the driving section 5 is a slide mechanism. As an example, the slide mechanism may have motors, gears, guide rails, and the like.

Face support unit 110 supports the subject's face. The face support unit 110 has a forehead rest 111 and a chin rest 112 . The subject's forehead is brought into contact with the forehead rest 111 . The chin of the subject is placed on the chin rest 112 .

A photographing optical system 3 (see FIG. 2) for photographing the subject's eye E is housed inside the photographing unit 2 . The imaging optical system 3 will be described with reference to FIG. The scanning fundus imaging apparatus 1 of this embodiment includes an SLO optical system 500, an OCT optical system 300, an alignment index projection optical system 27, an anterior segment imaging optical system 200, and the like as the imaging optical system 3. FIG.

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 L<b>1 of the SLO optical system and the optical axis L<b>2 of the OCT optical system 300 are made coaxial by the dichroic mirror 12 . Also, the optical axis L2 of the OCT optical system 300 and the optical axis L3 of the anterior segment 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 segment imaging optical system 200 are made coaxial by the half mirror 201 . An objective lens 11 is arranged on the common optical path 10 (common optical axis) of the SLO optical system 500 , the OCT optical system 300 , and the anterior segment imaging optical system 200 .

Hereinafter, the OCT measurement light that the OCT optical system 300 emits to the subject's eye 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 E to be examined is simply referred to as laser light.

<SLO optical system>
The SLO optical system 500 is used to obtain a front image of the fundus Er. For example, the SLO optical system 500 includes, in addition to the objective lens 11 and the dichroic mirror 12, 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 .

The SLO optical system 500 irradiates the fundus Er with 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 near-infrared laser light. As the laser light source 56, for example, an LED light source, an SLD light source, or the like may be used.

The scanning unit 52 is arranged in the optical path of the laser beam. In this embodiment, the scanning unit 52 is used to scan the laser beam in the transverse direction (XY direction in FIG. 1) on the fundus Er. In this embodiment, the scanning unit 52 includes two optical scanners (for example, a polygon scanner, a galvanomirror, etc.), and by driving the two optical scanners, the laser light from the laser light source 56 is projected onto the fundus Er. Scan two-dimensionally. For example, the scanning field angle 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.

In this embodiment, a condenser lens 57 , a confocal aperture 58 (eg, a pinhole plate), and a light receiving element 59 are arranged on the reflective side of the beam splitter 54 . A confocal aperture 58 is arranged at a position conjugate to the fundus Er.

Here, the laser light emitted from the laser light source 56 is incident on the scanning section 52 via the collimator lens 55 , the beam splitter 54 and the visibility correction section 53 . Then, the scanning unit 52 changes the reflection direction of the laser beam. The laser light that has passed through the scanning unit 52 is transmitted through the dichroic mirror 12 . Furthermore, the laser light passes through the objective lens 11 and is focused on the fundus Er.

The laser light reflected by the fundus Er traces the optical path from the objective lens 11 to the beam splitter 54 in reverse. The laser light is reflected by the beam splitter 54 , passes through the condensing 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 section 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 it in the storage unit 72 . The control unit 71 may display the generated front image on the monitor 73 .

<Diopter Corrector>
The diopter correction unit 53 corrects the diopter of the subject's eye. The diopter correction unit 53 adjusts the dioptric correction amount according to the refractive error of the eye E to be examined, and converges the light emitted from the laser light source 56 on the fundus Er of the eye E to be examined. 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 section 53b may be composed of a motor and a slide mechanism.

FIG. 3 is a diagram for explaining the relationship between the diopter correction amount and the fundus conjugate position. FIG. 3A shows a case where the subject's eye E is myopic. FIG. 3B shows the case where the subject's eye E is a hyperopic eye. In FIG. 3, the fundus conjugate position is marked with "x".

The fundus conjugate position P1 on the common optical path 10 (on the optical axis L1) changes according to the refractive error of the eye E to be examined. For example, in a myopic eye, the larger the refractive error toward the minus diopter side, the closer the fundus conjugate position P1 is to the objective lens 11 (see FIG. 3A). Further, for example, in a hyperopic eye, the larger the refractive error toward the plus diopter side, the closer the fundus conjugate position P1 is to the dichroic mirror 12 (see FIG. 3B). The diopter correction unit 53 moves the focusing lens 53a by driving the lens driving unit 53b, thereby changing at least a conjugate position (not shown) formed with respect to the focusing lens 53a, and confocal with the fundus Er (fundus conjugate position P1). It is adjusted so that it is in a conjugate relationship with the opening 58 .

In this embodiment, the diopter correction unit 53 is configured so that the refractive error of the eye E to be examined can be corrected from −15D to +15D. At this time, the fundus conjugate position P1 corresponding to the subject's eye E can 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 subject's eye E is -15D corresponds to the position R1a. For example, it corresponds to the first fundus conjugate position and position R1b when the subject's eye E is +15D.

<OCT optical system>
The OCT optical system 300 is used, for example, to capture a tomographic image of the tissue of the eye E to be examined. The OCT optical system 300 includes, in addition to the objective lens 11, the dichroic mirror 12, and the half mirror 201, an OCT light source that emits low coherent light, a light splitter that splits light emitted from the light source into measurement light and reference light, and an eye to be examined. A measurement optical system that guides the measurement light to E, a scanning unit that scans the measurement light in the transverse direction on the fundus of the eye to be examined E, a reference optical system that generates reference light, and detects an interference signal resulting from synthesis of the measurement light and the reference light. A configuration including a detector and the like may also be used. 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 Japanese Patent Application Laid-Open No. 2019-134896 may be referred to.

For example, the OCT optical system 300 splits OCT light emitted from an OCT light source into measurement light and reference light by a light splitter. The measurement light reaches the fundus of the subject's eye E through the half mirror 201 , the dichroic mirror 12 , and the objective lens 11 . The OCT optical system 300 acquires an OCT signal of the fundus of the subject's eye E by receiving interference light between the measurement light reflected by the fundus of the subject's eye E and the reference light, and inputs the OCT 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 it in the storage unit 72 . The control unit 71 may display the generated front image on the monitor 73 .

<Alignment target projection optical system>
The alignment index projection optical system 27 is used to project an alignment index toward the cornea of the eye E to be examined. 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, optical members such as lenses and mirrors may be provided. For example, the light sources 27a are arranged in a ring shape around 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 eye E to be examined, and is also used as anterior ocular segment illumination light for illuminating the anterior ocular segment of the eye E to be examined. .

<Anterior segment imaging optical system>
The anterior segment imaging optical system 200 is used to obtain a front observation image of the anterior segment. In this embodiment, the anterior segment imaging optical system 200 includes a lens 202 and an imaging element 203 in addition to the objective lens 11 , dichroic mirror 12 and half mirror 201 . The imaging device 203 is, for example, a two-dimensional imaging device such as a CCD. The imaging element 203 images the anterior segment of the subject's eye E illuminated by the light source 27a. A signal output from the imaging device 203 is input to a control unit 71, which will be described later. The control unit 71 may generate an anterior segment 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 .

<Sharing the optical path of the SLO optical system and the OCT optical system>
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 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 .

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

A polygon scanner is used as one of the scanning units 52 in this embodiment. For example, since a polygon scanner rotates at high speed, a physical load is likely to be applied to the rotating shaft. 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 compared to the case where the rotation axis is arranged in an oblique direction. can be done. In addition, by arranging the SLO optical system 500 on the transmission side, the direction of reflection of the laser light by the scanning unit 52 and the direction of scanning the fundus Er can be made the same. do not necessarily have to. Therefore, complication of the SLO optical system 500 can be suppressed.

In this embodiment, the dichroic mirror 12 reflects measurement light in the OCT optical system 300 (that is, light with a wavelength emitted from an OCT light source (not shown)). For example, the measurement light of the OCT optical system 300 enters the dichroic mirror 12 in 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 enters from the lower side of the dichroic mirror 12 and is guided to the first common optical path 10 by being reflected. For this reason, the photographing unit 2 is prevented from protruding to a position higher than the subject's eye E, and when the examiner assists opening the eyelid of the subject's eye E, it becomes easier for the examiner to reach over the photographing unit 2. . Note that the direction in which the measurement light is incident on the dichroic mirror 12 may be tilted with respect to the vertical direction.

<Artifact reflection>
FIG. 4 is a diagram illustrating the arrangement of the wall portion 100 of the imaging section 2. As shown in FIG. Here, part of the laser light from the SLO optical system 500 may be reflected without passing through the dichroic mirror 12 . For example, part of such laser light (hereinafter referred to as split light) travels in a direction mirror-symmetrical to the common optical path 10 with respect to the dichroic mirror 12 . Therefore, on the optical axis L4 of the separated light, the 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.

The second fundus conjugate position P2 on the optical axis L4 changes according to the refractive error of the eye E to be examined. For example, in the case of a myopic eye, the greater the refractive error toward the minus diopter side, the closer the first fundus conjugate position P1 is to the objective lens 11. exist at a distance. For example, in the case of a hyperopic eye, the larger the refractive error toward the plus diopter side, the closer the first fundus conjugate position P1 is to the dichroic mirror 12. exists in a position close to For example, when the first fundus conjugate position P1 is positioned at position R1a in range R1, the second fundus conjugate position P2 is positioned at position R2a. For example, when the first fundus conjugate position P1 is positioned at position R1b, the second fundus conjugate position P2 is positioned at position R2b. That is, the fundus conjugate position P2 can exist in the range R2 from the position R2a to the position R2b on the optical axis L4.

For example, since the separated light is reflected upward by the dichroic mirror 12 , the separated light travels toward the wall section 100 of the photographing section 2 and reaches the wall section 100 .

Here, for example, when the wall portion 100 of the imaging unit 2 exists at a position Wa overlapping the second fundus conjugate position P2 formed on the optical axis L4 of the separated light as shown in FIG. appears as an artifact on the fundus image. In particular, the larger the refractive error of the subject's eye E toward the minus diopter side, the higher the possibility that the second fundus conjugate position P2 overlaps the wall 100, and the appearance of such artifacts tends to pose a problem.

Therefore, in this embodiment, as shown in FIG. 4, the wall portion 100 of the imaging unit 2 is arranged at a distance from the movement range R2 of the second fundus conjugate position P2. More specifically, the wall portion 100 of the photographing section 2 is arranged at a distance from the position R2b on the optical axis L4. According to this, regardless of the refractive error of the eye to be examined E, the second fundus conjugate position P2 that is formed unintentionally and the wall portion 100 are suppressed from being overlapped, and the wall portion 100 is not reflected in a suitable fundus. image can be obtained.

In this embodiment, the dichroic mirror 12 is arranged at an angle d with respect to the first common optical path 10 . For example, angle d is less than or equal to 45 degrees. Preferably, the angle d is between 30 and 42 degrees, and in this embodiment is 40 degrees. The separated light is reflected perpendicularly when the angle d of the dichroic mirror 12 is 45 degrees, but is obliquely reflected when the angle d is different from 45 degrees, so that the optical axis L4 becomes longer. , the wall portion 100 is less likely to be reflected. Further, by setting the angle d of the dichroic mirror 12 to an angle different from 45 degrees, even if the wall portion 100 is reflected, its strength is lowered.

Artifacts can also be reduced by arranging the light absorbing member on the optical axis L4 without increasing the distance between the wall 100 and the second fundus conjugate position P2. However, when the light absorbing member overlaps the second fundus conjugate position P2, the light absorbing member is reflected even though its intensity is low, so there is a possibility that a good fundus image cannot be obtained. By arranging the wall portion 100 so as not to overlap the second fundus conjugate position P2 as in the present embodiment, it is possible to more effectively suppress the appearance of artifacts.

Artifacts can also be reduced by reducing the distance between the objective lens 11 and the dichroic mirror 12 without increasing the distance between the wall 100 and the second fundus conjugate position P2. This is because the second fundus conjugate position P2 is positioned closer to the dichroic mirror 12 than when the objective lens 11 and the dichroic mirror 12 are far apart, and is less likely to overlap the wall 100 . However, in such a configuration, the dichroic mirror 12 must be designed to be larger, which may increase the size of the imaging unit 2 . In addition, the movement range R1 in which the first fundus conjugate position P1 moves on the optical axis L1 is shortened, and the diopter capable of correcting the refractive error of the eye E to be examined is limited. If the wall portion 100 is arranged so as not to overlap the second fundus conjugate position P2 as in the present embodiment, it is possible to cope with a larger refractive error of the eye E to be examined, suppressing the appearance of artifacts, and 2 can be suppressed.

<Control section>
A control system of the scanning fundus imaging apparatus 1 will be described with reference to FIG. 5 is a block diagram showing the control system of the scanning fundus imaging apparatus 1. As shown in FIG. Each part of the scanning fundus imaging apparatus 1 is controlled by a control part 71 . The control unit 71 is a processing device (processor) having an electronic circuit that performs control processing of each unit of the scanning fundus imaging apparatus 1 and arithmetic processing. The control unit 71 is implemented by a CPU (Central Processing Unit), a memory, and the like. The control unit 71 is electrically connected to the storage unit 72 via a bus or the like.

The control section 71 is electrically connected to the lens drive section 53b of the visibility correction section 53 . The control unit 71 drives the lens driving unit 53b to move the focusing lens 53a in the optical axis direction, and adjusts the diopter correction amount so as to correct the refractive error of the eye E to be examined.

The control unit 71 is also electrically connected to each unit such as the driving unit 5 , the light source 27 a , 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 unit such as an OCT light source (not shown) and a detector (not shown) provided in the OCT optical system 300 .

Various control programs and the like are stored in the storage unit 72 . Temporary data and the like may be stored in the storage unit 72 . The image obtained by the scanning fundus imaging device 1 may be stored in the storage unit 72 . However, it is not necessarily limited to this, and the obtained fundus image and the like may be stored in an external storage device (for example, a storage device connected to the control unit 71 via LAN and WAN).

[motion]
The operation of the scanning fundus imaging apparatus 1 having the configuration as described above will be described. In addition, below, the case where the fundus image of the fundus Er of the eye E to be examined is acquired using the SLO optical system 500 will be described as an example.

First, when the subject brings the forehead into contact with the forehead rest 111 and puts the 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, controls the alignment index projection optical system 27 and the anterior eye imaging optical system 3, and acquires an anterior eye image. Further, the control unit 71 controls driving of the driving unit 5 based on the anterior segment image, and changes the positional relationship between the subject's eye E and the imaging unit 2 . For example, the control unit 71 drives the drive unit 5 to adjust the position of the optical axis L1 and the center of the pupil in the XY direction (see FIG. 1) so that the fundus Er can be photographed. The position in the Z direction (see FIG. 1) is adjusted so that For example, as a method for adjusting the positional relationship between the subject's eye E and the photographing unit 2, the method described in Japanese Patent Application Laid-Open No. 2013-179978 can be used. Of course, the examiner may operate the operation unit 8 to manually adjust the positional relationship between the subject's eye E and the photographing unit 2 .

When the eye E to be examined and the photographing unit 2 are aligned, the examiner operates the operation unit 8 (monitor 73) to input an operation start signal for starting photographing of the fundus image. The controller 71 turns on the laser light source 56 based on the operation start signal. Further, the scanning unit 52 is driven to scan the fundus Er of the subject's eye with the laser beam. The laser light reflected by 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 from the light receiving element 59 and causes the monitor 73 to display the image.

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 section 71 controls the diopter correction section 53 based on an operation signal from the operation section 8 to move the focusing lens 53b. For example, this causes the laser light to be focused on the fundus Er.

As described above, in this embodiment, the wall portion 100 of the photographing section 2 is arranged at a distance from the position P2b on the optical axis L4. By adjusting the diopter correction amount by the examiner, an appropriate fundus image in which the fundus Er is in focus and reflection of the wall portion 100 is suppressed is captured in real time. When the examiner inputs a trigger signal for photographing (for example, a release operation signal or the like) via the operation unit 8, the control unit 71 captures a fundus image.

As described above, in the scanning fundus imaging apparatus 1 of the present embodiment, the wall section 100 of the imaging section 2 is arranged at a distance from the second fundus conjugate position P2, so that the wall section 100 and the second fundus oculi The conjugate position P2 does not overlap, and the wall portion 100 is suppressed from appearing as an artifact on the fundus image. As a result, the fundus image of the subject's eye can be preferably acquired.

In the scanning fundus imaging apparatus 1 of the present embodiment, the dichroic mirror 12 is arranged near the objective lens 11 in the SLO optical system 500, and the light from the SLO optical system 500 passes through the dichroic mirror 12 and then passes through the optical member. The light is guided to the objective lens 11 without intervening. For example, by arranging the dichroic mirror 12 sufficiently away from the objective lens 11, it is possible to prevent the wall 100 from overlapping the second fundus conjugate position P2. Easy to grow in size. Even in the case where the objective lens 11 and the dichroic mirror 12 are brought close to each other to shorten the optical system as in this embodiment, the wall 100 is prevented from being reflected by considering the position of the wall 100. A fundus image can be acquired.

Further, the scanning fundus imaging apparatus 1 of the present embodiment can correct the dioptric power according to the refractive error of the eye to be examined, and is mirror symmetrical with the first fundus conjugate position P1 corresponding to the refractive error of the eye to be examined. The wall portion 100 is arranged at a distance from the second fundus conjugate position P2. That is, the wall portion 100 is arranged 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 when the eye to be examined has a large refractive error and the second fundus conjugate position R2 exists at a position further away from the dichroic mirror 12, the wall 100 is not reflected on the fundus image. can be suppressed.

Further, in the scanning fundus imaging apparatus 1 of the present embodiment, the optical path of the SLO optical system 500 is arranged on the transmission side of the dichroic mirror 12, and the optical path of an optical system (here, the OCT optical system 300) different from the SLO optical system. is placed on the reflection side of the dichroic mirror 12 . Thereby, the reflection direction in which the light from the SLO optical system 500 is reflected by the scanning unit 52 can be made the same as the scanning direction of the fundus Er. For example, when the light reflection direction and the scanning direction are different, it is 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.

Further, the scanning fundus imaging apparatus 1 of the present embodiment couples the optical path of the SLO optical system 500 from the working distance direction of the dichroic mirror 12, and dichroically couples the optical path of the optical system (OCT optical system 300) different from the SLO optical system. The connection is made from below the mirror 12 . As a result, part of the light (separated light) from the SLO optical system 500 does not pass through the dichroic mirror 12 and is reflected upward. For example, by arranging the OCT optical system 300 below the SLO optical system 500 in this way, it is possible to prevent the photographing 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 over the scanning fundus imaging apparatus 1 and opens the eyelids of the examinee, it is easy to reach, and the burden on the examiner can be reduced.

[Transformation example]
In this embodiment, the case where the reflection of the wall portion 100 in the fundus image may occur depending on the refractive error of the eye E to be examined has been described as an example, but the present invention is not limited to this. For example, reflection of the wall portion 100 may also occur depending on the scanning angle of view of the fundus Er in the SLO optical system 500 . Therefore, the wall section 100 may be arranged in consideration of the scanning angle of view of the fundus Er.

FIG. 6 is a diagram for explaining the relationship between the angle of view for photographing the subject's eye and the wall portion 100 of the photographing section 2. As shown in FIG. Since the SLO optical system 500 scans the eye E to be examined with laser light in the transverse direction (XY direction), the first fundus conjugate position P1 on the optical axis L1 and the second fundus conjugate position P2 on the optical axis L4 are , exist as a first fundus conjugate plane M1 and a 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. Therefore, as the scanning angle of view of the fundus Er increases, the second fundus conjugate plane M2 overlaps the wall 100, and the wall 100 is more likely to appear as an artifact on the fundus image. However, by arranging the wall section 100 in consideration of the scanning angle of view of the fundus Er, it is possible to suppress artifacts and obtain a suitable fundus image. Of course, the wall portion 100 may be arranged in consideration of both the diopter correction amount corresponding to the refractive error of the eye to be examined E and the scanning angle of view of the fundus Er.

In this embodiment, the configuration in which 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 has been described as an example, but the present invention is not limited to this. For example, the SLO optical system 500 may be arranged on the reflection side of the dichroic mirror 12 and the OCT optical system 300 may be arranged on the transmission side of the dichroic mirror 12 . In this case, part of the light (separated light) in the laser light of the SLO optical system 500 may be transmitted through the dichroic mirror 12 without being reflected. formed unintentionally. However, even with such a configuration, by arranging the wall portion 100 of the imaging unit 2 so as not to overlap the fundus conjugate position, it is possible to suppress the wall portion from appearing on the fundus image.

When the SLO optical system 500 is arranged on the reflection side of the dichroic mirror 12 , the laser light of the SLO optical system 500 may enter the dichroic mirror 12 from below. By configuring in this way, the photographing unit 2 is prevented from protruding to a position higher than the eye E to be examined. Of course, the laser light may be configured to enter from the upper side of the dichroic mirror 12, but it is preferable to enter from the lower side of the dichroic mirror 12 for the reason described above.

In this embodiment, the optical path of the SLO optical system 500 and the optical path of the OCT optical system 300 have been described as an example of a configuration in which the dichroic mirror 12 couples the optical path, 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 segment imaging optical system 200, etc.), the effect of the separated light Reflection of the wall portion 100 occurs. In this case, instead of the dichroic mirror 12, a half mirror or the like may be used. For example, even in such a case, by arranging the wall part 100 so as not to overlap the second fundus conjugate position P2, an appropriate fundus image with suppressed artifacts can be obtained.

In this embodiment, the case where the imaging unit 2 protects the dichroic mirror 12 and other optical members has been described as an example, but the present invention is not limited to this. For example, when the surface of the dichroic mirror 12 is covered with dust or scratched, artifacts resulting from the dust or scratches are likely to appear in the fundus image. Therefore, the photographing unit 2 may additionally include a 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 (the objective lens 11 and the dichroic mirror 12) arranged in the first common optical path 10, as an example.

In this embodiment, even when the protective cover is provided in this manner, the wall portion of the protective cover is arranged so as not to overlap the second fundus conjugate position P2. According to this, even if part of the light (separated light) from the SLO optical system 500 is unintentionally reflected by the dichroic mirror 12, the wall portion of the protective cover is prevented from appearing as an artifact, and a suitable fundus oculi image can be obtained.

Also, in the above embodiments, 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 captures a fundus image by two-dimensionally scanning a light flux irradiated in a spot 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 fundus image is captured by scanning a line-shaped light beam on the fundus in one direction. In a line scan type optical system, a light receiving element (for example, a line sensor) can also serve as a confocal aperture function. In this case, by arranging the light receiving element at the fundus conjugate position, reception of stray light is suppressed even if an aperture separate from the light receiving element is not necessarily arranged at the fundus conjugate position. Note that even in a line scan type optical system, an aperture separate from the light receiving element may be arranged at the fundus conjugate position.

1 scanning type fundus imaging device 10 first common optical path 11 objective lens 12 dichroic mirror 52 scanning unit 53 dioptric correction unit 58 confocal aperture 59 light receiving element 100 wall 300 OCT optical system 500 SLO optical system

Claims (7)

A scanning fundus imaging device for imaging the fundus of an eye to be examined,
A first optical system having a confocal aperture arranged at a position conjugate with the fundus, scanning and irradiating light to the fundus through an objective lens, and emitting light from the fundus through the confocal aperture. a first optical system for capturing a fundus image of the subject's eye by receiving the returned light of the light;
a second optical system different from the first optical system;
an optical path coupling mirror that couples the first optical path of the first optical system and the second optical path of the second optical system;
a protective member that protects at least the optical path coupling mirror;
with
the first fundus conjugate position of the first optical system exists at least in a common optical path on the subject's eye side in the first optical path and the second optical path;
A third optical path of the separated light is formed by causing the separated light, which is a part of the light from the first optical system, to travel in a direction different from the common optical path by the optical path coupling mirror. A second fundus conjugate position mirror-symmetrical to the first fundus conjugate position with respect to the optical path coupling mirror is formed on the optical path,
A scanning fundus imaging apparatus, wherein the wall of the protection member is spaced apart from the second fundus conjugate position. The scanning fundus imaging device of claim 1,
The first optical system has the optical path coupling mirror near the objective lens, and the light is guided to the objective lens without passing through an optical member after passing through the optical path coupling mirror,
A scanning fundus imaging apparatus, wherein the first fundus conjugate position is positioned between the objective lens and the optical path coupling mirror. In the scanning fundus imaging device according to claim 1 or 2,
diopter correction means capable of correcting the diopter of the eye to be inspected in the first movement range of the first fundus conjugate position;
a control means for controlling the dioptric correction means and adjusting a dioptric correction amount according to the dioptric power of the subject's eye;
with
The scanning fundus imaging apparatus, wherein the wall portion of the protective member is spaced apart from a second movement range of the second fundus conjugate position mirror-symmetrical to the first movement range. In the scanning fundus imaging device according to any one of claims 1 to 3,
The independent optical path of the first optical path in the first optical system is arranged on the transmission side of the optical path coupling mirror, and the independent optical path of the second optical path in the second optical system is arranged on the reflection side of the optical path coupling mirror. is,
A scanning fundus imaging apparatus, wherein the separated light is reflected light in which part of the light from the first optical system is reflected without passing through the optical path coupling mirror. In the scanning fundus imaging device according to claim 4,
the reflection side of the optical path coupling mirror on which the independent optical path of the second optical system is arranged is the lower side of the optical path coupling mirror;
The separated light is reflected by the optical path coupling mirror upward, which is the side opposite to the reflection side, to form the third optical path and the second fundus conjugate position,
A scanning fundus imaging apparatus, wherein a wall portion of the protection member on the side of the optical path coupling mirror is spaced apart from the second fundus conjugate position. In the scanning fundus imaging device according to any one of claims 3 to 5,
The scanning fundus imaging apparatus, wherein the diopter correction amount is a correction amount that can correspond to at least -15D. In the scanning fundus imaging device according to any one of claims 1 to 6,
A scanning-type fundus imaging apparatus, wherein a scanning angle of view of the light on the fundus of the eye in the first optical system is 40 degrees or more.

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