JP2016123467A - Fundus photographing device and wide-angle lens attachment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfactorily capture a fundus image having a wide angle of view. A fundus imaging apparatus (1) emits laser light of at least three colors of red, green, and blue, and a laser beam emitted from the light source (11) to scan the fundus on the fundus. A scanning unit 15 that changes the traveling direction, and a turning point Q that is arranged between the eye E and the scanning unit 15 and that is rotated by the operation of the scanning unit 15 is formed by the laser light guided from the scanning unit 15. A second objective optical system 230. Here, the second objective optical system 230 bends the laser light guided from the scanning unit 15 toward the optical axis L3 of the second objective optical system 230, thereby making the scanning range of the laser light on the fundus Er 90 degrees or more. The second objective optical system 230 further includes at least a cemented lens 232 that corrects chromatic aberration of magnification generated in the objective optical system 230 for at least three laser beams of red, green, and blue. [Selection] Figure 7

Description

  The present invention relates to a fundus imaging apparatus that captures an image of the fundus and a wide-angle lens attachment that can be attached to the fundus imaging apparatus.

  2. Description of the Related Art Conventionally, a fundus imaging apparatus that obtains an image of a fundus by scanning a laser beam with the fundus of an eye to be examined is known. Among such apparatuses, an apparatus that captures an image with a wide imaging angle of view is known. In such an apparatus, the laser beam is bent toward the turning point by an objective optical system provided between the scanning unit and the eye to be examined. The laser beam is turned around a turning point according to the operation of the scanning unit. In this way, the fundus is scanned.

JP 2009-11811 A

  In order to widen the shooting angle of view, it is necessary to largely bend the laser beam with the objective optical system, and in designing the optical system, it is necessary to consider various aberrations that can be caused by this.

  The present disclosure has been made in view of the problems of the related art, and an object thereof is to provide a novel fundus photographing apparatus and a wide-angle lens attachment that can favorably capture a fundus image having a wide field angle.

  The fundus imaging apparatus according to the first aspect of the present invention is emitted from the light source that emits at least a laser beam having a first wavelength and a laser beam having a second wavelength different from the first wavelength, and the light source. A scanning unit that changes the traveling direction of the laser beam to scan the laser beam on the fundus, and the laser beam that is disposed between the eye to be examined and the scanning unit, and the laser beam guided from the scanning unit is used for the operation of the scanning unit. An objective optical system that forms a swivel point that is swung with it, and images the fundus of the eye to be inspected using light from the fundus that is guided by the laser beam that passes through the swivel point and is guided to the fundus In the fundus imaging apparatus, the objective optical system folds the laser light guided from the scanning unit toward the optical axis of the objective optical system, thereby making the scanning range of the laser light on the fundus 90 ° or more in full angle. A shall, said objective optical system further includes at least a cemented lens for correcting chromatic aberration of magnification occurring at least said objective optical system with respect to the laser light of the laser light and the second wavelength of the first wavelength.

  A wide-angle lens attachment according to a second aspect of the present disclosure includes a light source that emits at least a laser beam having a first wavelength and a laser beam having a second wavelength different from the first wavelength, and a laser beam emitted from the light source. A scanning unit that changes a traveling direction of laser light to scan the fundus on the fundus, and a laser beam that is disposed between the eye to be examined and the scanning unit, and the laser light guided from the scanning unit accompanies the operation of the scanning unit. A first objective optical system that forms a first swivel point that is swiveled, and the fundus of the subject's eye using light from the fundus that is guided by the laser light that passes through the first swivel point and is guided to the fundus A wide-angle lens attachment that is mounted on a subject-side housing surface of a fundus imaging apparatus that captures an image of the fundus, and that widens the imaging field angle of the fundus image, the attachment being on the housing surface having an examination window Attached equipment In the state, there is provided a second objective optical system that forms a second turning point where the laser light that has passed through the first turning point is further turned in accordance with the operation of the scanning unit, and the second objective optical system Includes at least a cemented lens that corrects at least the lateral chromatic aberration generated in the first objective optical system with respect to the first wavelength laser beam and the second wavelength laser beam.

  According to the present disclosure, it is possible to satisfactorily capture a fundus image with a wide angle of view.

It is a schematic block diagram which shows the external appearance of the fundus imaging apparatus 1 in 1st Embodiment. 2 is a schematic diagram showing an optical system in the apparatus main body 2 of the fundus imaging apparatus 1. FIG. It is a figure when the wide angle lens attachment 3 is arrange | positioned between the eye to be examined and the 1st objective optical system 31. FIG. 3 is a block diagram showing a control system of the fundus imaging apparatus 1. FIG. It is a schematic diagram which shows the correspondence of the pixel in the fundus image I in the mounting state and non-mounting state of the wide-angle lens attachment 3 and the scanning order of the scanning unit. It is a schematic diagram which shows the wide angle lens attachment 3 in 2nd Embodiment. It is a schematic diagram which shows the wide angle lens attachment 3 in 3rd Embodiment. It is a figure which shows the example of a change of the wide angle lens attachment 3 of 3rd Embodiment, (a) is an example in which the lens surface 231b was formed in the concave surface, (b) is the lens surface 231b in the convex surface. It is an example formed. In the wide angle lens attachment 3 of 3rd Embodiment, it is a figure for showing the difference in the design according to the direction of the 2nd objective lens 232. FIG. It is a schematic diagram which shows an optical system at the time of applying the objective-lens optical system of this indication to the imaging device of a type which changes an imaging | photography field angle by replacement | exchange of an objective lens.

  Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. First, the schematic configuration of the fundus imaging apparatus 1 according to the first embodiment will be described with reference to FIG. In the first embodiment, a case where a scanning laser opthalmoscope (SLO) is used as the fundus imaging apparatus 1 will be described.

  As shown in FIG. 1, the fundus imaging apparatus 1 includes a main body (apparatus main body) 2 and a wide-angle lens attachment 3. In the first embodiment, the main body 2 includes a main optical system (see FIG. 2) and a control system (see FIG. 4) when the fundus photographing apparatus 1 captures a fundus image. In the first embodiment, the wide-angle lens attachment 3 is configured to be detachable from the subject-side casing surface of the main body 2. The wide-angle lens attachment 3 is attached to the main body 2 to widen the imaging field angle of the fundus image obtained by the main body 2.

  In the first embodiment, the main body 2 includes a measurement unit 4, an alignment mechanism 5, a base 6, a face support unit 7, and a sensor 8. The measuring unit 4 stores an optical system for imaging the eye E. This optical system will be described later with reference to FIG.

  The alignment mechanism 5 is used for aligning the apparatus with respect to the eye E. The alignment mechanism 5 of the present embodiment moves the measurement unit 4 three-dimensionally with respect to the base 6. That is, they are moved in the Y direction (up and down direction), the X direction (left and right direction :), and the Z direction (front and back direction).

  As shown in FIG. 1, the face support unit 7 supports the face of the subject in a state where the eye to be examined is opposed to the measurement unit. In the first embodiment, the face support unit 7 is provided on the base 6.

  The sensor 8 is a detection unit that detects wearing of the wide-angle lens attachment 3. The sensor 8 outputs an electrical signal corresponding to the wearing state of the wide-angle lens attachment 3. For example, the sensor 8 continuously outputs electrical signals having different voltage values when the wide-angle lens attachment 3 is attached to the main body 2 and when the wide-angle lens attachment 3 is not attached to the main body 2. It may be a thing. Such a sensor 3 may be a contact sensor such as a microswitch, or may be a non-contact sensor such as a photoelectric sensor or a magnetic sensor.

  The fundus imaging apparatus 1 may be an apparatus integrated with another ophthalmologic apparatus such as an optical coherence tomography (OCT) or a perimeter.

  Next, the optical system of the main body 2 will be described with reference to FIG. Here, the main body 2 in a state where the wide-angle lens attachment 3 is not attached is shown.

  In the first embodiment, the main body 2 includes a light projecting optical system 10 and a light receiving optical system 20. The light projecting optical system 10 projects laser light (measurement light) to each position in the imaging range on the fundus Er of the eye E. In the first embodiment, the light projecting optical system 10 includes a laser light emitting unit 11, a perforated mirror 12, a lens 13, a lens 14, a scanning unit 15, and a first objective optical system 16.

  The laser beam emitting unit 11 is a light source (that is, a laser light source) of the light projecting optical system 10. For convenience of explanation, in the first embodiment, the laser light emitting unit 11 will be described as emitting only monochromatic light.

  Laser light from the laser light emitting unit 11 passes through the aperture of the perforated mirror 12, passes through the lens 13 and the lens 14, and then travels to the scanning unit 15. The light beam reflected by the scanning unit 15 passes through the first objective optical system 16 and then converges on the fundus Er of the eye E to be examined. As a result, light scattered and reflected by the fundus Er (hereinafter referred to as fundus reflected light) is emitted from the pupil.

  In the first embodiment, the lens 13 is configured to be movable in the optical axis direction L1 by a drive mechanism 13a (see FIG. 4). Depending on the position of the lens 13, the diopter of the light projecting optical system 10 and the light receiving optical system 20 changes. Therefore, in the first embodiment, the diopter error of the eye E is corrected (reduced) by adjusting the position of the lens 13. Of course, the diopter error of the eye E may be corrected by displacing the lens 14.

  The scanning unit 15 is a unit that changes the traveling direction of the laser light guided from the laser light emitting unit 11 (deflects the laser light) in order to scan the laser light on the fundus. In the first embodiment, the scanning unit 15 includes a resonant scanner 15a and a galvanometer mirror 15b.

  As the scanning unit 15, for example, an acousto-optic device (AOM) that changes the traveling (deflection) direction of light may be used in addition to a reflection mirror (galvano mirror, polygon mirror, resonant scanner).

  In the first embodiment, the resonant scanner 15a deflects the laser light projected onto the fundus of the eye E to be examined in a predetermined direction. As shown in FIG. 2, the light that has passed through the resonant scanner 15a travels to the galvanometer mirror 15b. In the first embodiment, the resonance scanner 15a is rotated by the motor 15c (see FIG. 4), so that the irradiation position (scan position) of the laser light on the fundus Er moves in the horizontal direction (that is, the X direction). In the first embodiment, main scanning in the X direction is performed by the resonant scanner 15a.

  In the first embodiment, the galvanometer mirror 15b further deflects the laser light that has passed through the resonant scanner 15a in a direction different from that of the resonant scanner 15a. As shown in FIG. 2, the light that has passed through the galvano mirror 15 b travels to the first objective optical system 16. In the first embodiment, the galvano mirror 15b is rotated by the motor 15d (see FIG. 4), so that the irradiation position of the laser light on the fundus Er moves in the vertical direction (that is, the Y direction). In the first embodiment, sub-scanning in the Y direction is performed by the galvanometer mirror 15b. In the first embodiment, main scanning in the X direction by the resonant scanner 15a and sub scanning in the Y direction by the galvano mirror 15b are performed in a predetermined scanning order, so that the laser light is two-dimensionally displayed on the fundus Er. Scanned.

  The first objective optical system 16 allows the laser light that has passed through the scanning unit 15 to pass through the pupil position of the eye E when the wide-angle lens attachment 3 is not attached to the main body unit 2. The first objective optical system 16 has a positive power. For example, the first objective optical system 16 of the first embodiment includes two convex lenses (a first convex lens 16a and a second convex lens 16b) arranged in series. The number of lenses included in the first objective optical system 16 is not limited to the above configuration. For example, the first objective optical system 16 may have a single lens. Moreover, the structure which has three or more lenses may be sufficient. In addition, each lens of the first objective optical system 16 may be an aspherical lens, a compound lens composed of a plurality of lenses, or the like as required for aberration correction. The first objective optical system 16 may include an optical member other than a lens (for example, a reflection mirror).

  In the first embodiment, in the first objective optical system 16, the laser light (more specifically, the principal ray of the laser light) that has passed through the scanning unit 15 is swung on the optical axis L <b> 3 of the first objective optical system 16. A first turning point P is formed. In the first embodiment, the first turning point P is formed at a position optically conjugate with the scanning unit 15 (for example, an intermediate point between the resonant scanner 15a and the galvanometer mirror 15b) via the first objective optical system 16. The The laser light that has passed through the scanning unit 15 passes through the first objective optical system 16 and is irradiated to the fundus Er through the first turning point P. For this reason, the chief ray of the laser light that has passed through the first objective optical system 16 is turned around the first turning point P as the scanning unit 15 operates. As a result, in the example of FIG. 2, the laser light is scanned two-dimensionally on the fundus Er. Since the first turning point P of the laser beam and the pupil position of the eye E to be examined are matched in advance, vignetting in the iris is suppressed and the laser beam is guided well to the fundus. As a result, the fundus image is captured well.

  Next, the light receiving optical system 20 will be described. The light receiving optical system 20 receives, with the light receiving element 25, fundus reflection light emitted from the pupil along with the laser light from the light projecting optical system 10. The light receiving optical system 20 of the first embodiment shares the members arranged from the perforated mirror 12 to the first objective optical system 16 on the optical path of the light projecting optical system 10 with the light projecting optical system 10. Yes. The light receiving optical system 20 of the first embodiment includes a lens 22, a pinhole plate 23, a lens 24, and a light receiving element 25.

  When laser light is irradiated on the fundus of the eye E, the fundus reflection light of the laser light travels backward through the projection optical system 10 described above, is reflected by the perforated mirror 12, and is guided to the lens 22. Note that the pupil position of the eye E and the opening of the perforated mirror 12 have an optically conjugate relationship. On the downstream side of the lens 22, the light from the fundus Er is focused at the pinhole of the pinhole plate 23 and received by the light receiving element 25 through the lens 24. In the first embodiment, an APD (avalanche photodiode) having sensitivity in the visible region and the infrared region is used as the light receiving element 25.

  In this way, the optical system in the main body 2 of the first embodiment is formed. In the first embodiment, a fundus image of one frame is obtained based on scanning of the fundus Er for one frame with a laser beam.

  Next, the optical system in a state where the wide-angle lens attachment 3 is attached to the main body 2 will be described with reference to FIG. In FIG. 3, reference numeral 17 denotes an inspection window of the main body 2. Reference numeral 30 denotes an inspection window of the wide-angle lens attachment 3, and 33 denotes an incident window of the wide-angle lens attachment 3. For convenience, the inspection window and the entrance window are illustrated apart from the lens surface, but the lens surface may also serve as the inspection window. For example, the lens 16 a may also serve as the inspection window 17 of the main body 2. The lens 31a may also serve as the inspection window of the wide-angle lens attachment 3. In the first embodiment, a cover glass may be fitted in each inspection window and the entrance window for dust prevention.

  In the first embodiment, the wide-angle lens attachment 3 is attached to the subject-side housing surface of the main body 2 so that a second objective optical system 31 described later is disposed in the optical path of the laser light. For example, it is disposed in the vicinity of the inspection window 17 located between the first objective optical system 16 and the first turning point P.

  As shown in FIG. 3, the wide-angle lens attachment 3 mainly has a second objective optical system 31. The wide-angle lens attachment 3 of the first embodiment has a diopter correction lens 32 (a diopter correction lens optical system). When the wide-angle lens attachment 3 is attached to the main body 2, the optical system included in the wide-angle lens attachment 3 is disposed between the inspection window 17 of the main body 2 and the eye E to be examined.

  In the first embodiment, when the wide-angle lens attachment 3 is mounted, the second objective optical system 31 and the diopter correction lens 32 are disposed in the optical path of the laser light. In the mounted state of the wide-angle lens attachment 3, the laser light incident from the incident window 33 through the first objective optical system 16 and the inspection window 17 of the main body 2 passes through the diopter correction lens 32 and the first turning point P. , Passing through the second objective optical system 31. Although details will be described later, in the first embodiment, the diopter correction lens 32 is disposed at a first turning point P formed by the first objective optical system 16. As a result, the laser beam passes near the center of the diopter correction lens 32. Therefore, the tilt and height of the laser beam are not easily affected by the power of the diopter correction lens 32.

  The second objective optical system 31 forms a second turning point Q when the wide-angle lens attachment 3 is mounted. The second turning point Q is a point where the laser light (more specifically, the chief ray of the laser light) that has passed through the first turning point P is further turned along with the operation of the scanning unit 15. In the first embodiment, the second turning point Q is formed at a position optically conjugate with the scanning unit 15 (for example, an intermediate point between the resonant scanner 15a and the galvanometer mirror 15b) via the second objective optical system 31. The The second turning point Q is formed on the optical axis of the second objective optical system 31. In the first embodiment, since the optical axis of the second objective optical system 31 is coaxial with the optical axis L3, the symbol L3 is used to indicate the optical axis of the second objective optical system 31.

  In the first embodiment, the second objective optical system 31 includes a first objective lens 31a, a second objective lens 31b, and a third objective lens 31c in order from those arranged near the eye to be examined. In the first embodiment, the second objective optical system 31 may be a lens optical system having a large effective aperture with respect to the maximum value (h1max) of the principal ray height h1 in the laser light passing through the inspection window 17. . For example, a lens having a larger effective diameter than the first convex lens 16a is used for the first objective lens 31a and the second objective lens 31b. Further, for the third objective lens 31c, a lens having a larger effective diameter than the first convex lens 16a may be used. However, in the first embodiment, h1 represents the principal ray height with respect to the optical axis L3 of the first objective optical system 16.

  As shown in FIG. 3, the second objective optical system 31 (the lenses 31 a to 31 c) is arranged on the eye E side with respect to the first turning point P. More specifically, the second objective optical system 31 of the first embodiment has an interval larger than the interval from the inspection window 17 to the first turning point P, the lens surface closest to the light source (in the first embodiment, A lens surface on the light source side of the third objective lens 31c) and the first turning point P are arranged apart from each other. As a result, in the first embodiment, a laser beam having a principal ray height higher than the laser beam passing through the inspection window 17 is incident on the lens surface closest to the light source of the second objective optical system 31.

  In the first embodiment, each of the objective lenses 31a to 31c has a positive power. However, the present invention is not necessarily limited to this, and it is sufficient that the second objective optical system 31 as a whole has a positive power. A lens disposed in the second objective optical system 31 for bending the laser light toward the optical axis L3 of the second objective optical system 31 at a position higher than the principal ray height h1 of the laser light in the inspection window 17. (For example, in the first embodiment, each objective lens 31a, b, c) is included at least. The laser light after passing through the first turning point P is bent by this lens. The lens arranged to bend the laser beam bends, for example, a principal ray traveling in a direction away from the optical axis L3 toward a direction approaching the optical axis L3. In the first embodiment, the laser light bent by the third objective lens 31c and the second objective lens 31b is incident on the first objective lens 31a and further bent at a steep angle with respect to the optical axis L3. Therefore, the turning angle of the laser light turned around the second turning point Q is turned at a large angle with respect to the laser light turned around the first turning point P. As a result, the fundus imaging apparatus 1 has a wider angle of view for the non-mounted state when the wide-angle lens attachment 3 is mounted. For example, when the shooting angle of view when the wide-angle lens attachment 3 is not attached is about 30 ° to 60 °, the shooting angle of view in the attached state can be widened from 90 ° to 150 °.

  Here, as shown in FIG. 3, the principal ray height of the laser light passing through the lens surface closest to the eye E (in the first embodiment, the eye surface of the first objective lens 31a) is h2 ( However, when h2 is expressed as the principal ray height with respect to the optical axis L3 of the second objective optical system 31, the approximate working distance WD in the fundus imaging apparatus 1 is expressed by the following equation (1).

WD = h2max / tan (θ / 2) (1)
However, the working distance WD is the distance from the turning point where the pupil is placed to the lens surface closest to the eye to be examined. h2max is the maximum value of the chief ray height h2 of the laser light on the lens surface closest to the eye to be examined. θ is a turning angle (angle of the turning range). As shown in equation (1), the larger h2max is, the longer the working distance WD is. Here, the conventional wide-angle lens attachment (see Patent Document 1) is for widening the shooting angle of view at a position where the chief ray height of the laser light is lower than when passing through the inspection window of the apparatus main body. Lens was placed. As a result, in the conventional apparatus, the chief ray height of the laser beam (laser beam) on the lens surface closest to the eye to be examined is always lower than the chief ray height of the laser beam in the inspection window of the apparatus body, for example. . On the other hand, in the fundus imaging apparatus 1 of the first embodiment, the lenses 31 a to 31 c are arranged at positions where the chief ray height of the laser light is higher than the chief ray height h1 in the inspection window 17. As a result, in the first embodiment, the chief ray height of the laser beam on the lens surface closest to the eye to be examined is easily ensured as compared with the conventional apparatus. For example, as shown in FIG. 3, a design in which the chief ray height h2 of the laser beam on the lens surface closest to the eye E is higher than the chief ray height h1 of the laser beam in the examination window 17 is possible. Therefore, in the fundus imaging apparatus 1 of the first embodiment, when the wide-angle lens attachment 3 is attached to the main body unit 2, the interval between the eye to be examined and the wide-angle lens attachment 3 is easily secured.

  By the way, in order to widen the photographing angle of view of the fundus image, a method of replacing the objective lens of the apparatus main body with a lens for wide-angle photographing can be considered. However, in this method, when changing the photographing field angle of the fundus image, it is necessary to remove the objective lens of the apparatus main body once. Further, when the objective lens is removed, the inside of the apparatus main body is exposed. On the other hand, the fundus photographing apparatus 1 of the first embodiment can switch the photographing field angle of the fundus image by attaching / detaching the wide-angle lens attachment 3 without removing the objective lens of the apparatus main body. Therefore, according to the fundus imaging apparatus 1 of the first embodiment, the examiner or the like can switch the imaging angle of view with a simpler procedure. In addition, the fundus imaging device 1 of the first embodiment maintains the dustproof property of the device body even when the wide-angle lens attachment 3 is attached or detached.

  The second objective optical system 31 is not limited to the above configuration. For example, the second objective optical system 31 may have a configuration including an aspheric lens, a compound lens including a plurality of lenses, and the like. Further, the second objective optical system 31 may have a configuration having one lens (for example, an aspheric lens). Moreover, the structure which has 2 sheets or 4 or more lenses may be sufficient.

  The diopter correction lens 32 cancels the diopter change caused by the second objective optical system 31 (that is, cancels part or all of the diopter change). More specifically, the diopter correction lens 32 suppresses a difference in diopter of light incident on the eye E between the wearing state of the wide-angle lens attachment 3 and the non-wearing state. In the first embodiment, a lens having positive power (more specifically, a plano-convex lens having a convex surface directed toward the eye E to be examined) is used as the diopter correction lens 32.

  Here, for example, when the diopter change by the second objective optical system 31 is larger than the diopter adjustment range (for example, diopter adjustment range by movement of the lens 13) in the optical system of the main body 2 (for example, , About several tens of diopters). On the other hand, in the first embodiment, the diopter change caused by the second objective optical system 31 is canceled out by the diopter correction lens 32. Therefore, even if the diopter change by the second objective optical system 31 is larger than the diopter adjustment range in the optical system of the main body 2, a wide-angle fundus image can be favorably captured. Further, according to the diopter correction lens 32, the difference in diopter of the light incident on the eye E between the wearing state of the wide-angle lens attachment 3 and the non-wearing state can be reduced, so that the wide-angle lens attachment to the main body unit 2 is reduced. The adjustment of the diopter of the device accompanying the attachment / detachment of 3 is simplified or no adjustment is required.

  As shown in FIG. 3, in the first embodiment, the diopter correction lens 32 is disposed on the light source side with respect to the second objective optical system 31. More specifically, the diopter correction lens 32 of the first embodiment is disposed at the first turning point P. As a result, the laser beam passes near the center of the diopter correction lens 32. Therefore, a small diameter lens can be used as the diopter correction lens 32. In the first embodiment, the diopter correction lens 32 has positive power. However, the laser light passes near the center of the diopter correction lens 32. Therefore, the tilt and height of the laser beam are not easily affected by the power of the diopter correction lens 32. As a result, the distance between the inspection window 17 and the position where the principal ray height of the laser light after passing through the first turning point P is higher than h1 is suppressed. That is, the distance between the second objective optical system 31 and the inspection window 17 is suppressed. Therefore, the lengthening of the wide-angle lens attachment 3 can be suppressed. In the first embodiment, the diopter correction lens 32 is described as being located at the first turning point P. However, the diopter correction lens 32 is not necessarily limited to this, and the diopter correction is performed at other positions in the wide-angle lens attachment 3. A lens 32 may be arranged. However, the arrangement at the condensing point (for example, the position where the intermediate image f is formed in FIG. 3) where the laser beam is condensed in the attachment should be avoided.

  In the first embodiment, the diopter correcting lens 32 is located at the first turning point P only when the diopter correcting lens 32 and the first turning point P are completely coincident with each other. In other words, it is assumed that the diopter correction lens 32 is arranged with a certain degree of deviation from the first turning point P. The allowable deviation amount can be appropriately set in relation to the required accuracy.

  Next, the control system of the fundus imaging apparatus 1 will be described with reference to FIG. Main control of the fundus imaging apparatus 1 is performed by the control unit 100. The control unit 100 is a processing device having an electronic circuit that performs control processing of each unit of the fundus imaging apparatus 1 and calculation processing of measurement results.

  In the first embodiment, the control unit 100 is connected to the alignment mechanism 5, the sensor 8, the motors 15 c and 15 d, the light receiving element 25, and the monitor 50.

  The control unit 100 includes a CPU 101, a ROM 102, and a RAM 103. The CPU 101 is a processing device for executing various processes related to the fundus imaging apparatus 1. The ROM 102 is a nonvolatile storage device that stores various control programs and fixed data. The RAM 103 is a rewritable volatile storage device. The RAM 103 stores, for example, temporary data used for photographing and measuring the eye E.

  By the way, according to the wide-angle lens attachment 3 of the first embodiment, the laser light is bent by the second objective optical system 31 so that the direction of the laser light is reversed vertically and horizontally before and after passing through the second objective optical system 31. Is done. That is, the inclination of the laser light at the first turning point P and the inclination of the laser light at the second turning point Q are reversed across the optical axis L3. As a result, for example, when the shooting method and the image generation method are the same in the mounting state and the non-mounting state of the wide-angle lens attachment 3, one of the mounting state and the non-mounting state of the wide-angle lens attachment 3 is: An upright image in which the upper and lower left and right of the fundus coincides with the upper and lower and right and left of the image is obtained, and on the other hand, an inverted image in which the upper and lower and right and left of the fundus and the upper and lower and right and left of the image are inverted is obtained. For example, in the fundus imaging device 1 of the first embodiment, an erect image is acquired when the wide-angle lens attachment 3 is not attached, and an inverted image is acquired when the wide-angle lens attachment 3 is attached.

  On the other hand, the control unit 100 according to the first embodiment refers to a fundus image captured when the wide-angle lens attachment 3 is not attached to a fundus image in which the pixel arrangement corresponding to the scanning order of the scanning unit 15 is vertically and horizontally reversed. Perform image processing to generate images. In the first embodiment, this image processing is performed based on an input of a detection signal corresponding to the mounting state of the wide-angle lens attachment 3 output from the sensor 8 to the control unit 100. That is, the inverted image captured in the mounted state of the wide-angle lens attachment 3 is processed.

  Here, the correspondence relationship between the pixels in the fundus image I and the scanning order of the scanning unit 15 when the wide-angle lens attachment 3 is attached and not attached is shown as an example in FIG. In FIG. 5, the arrows on the image indicate the order of main scanning in the scanning unit 15, and the numbers attached to the arrows indicate the order of sub-scanning in the scanning unit 15. In the fundus image obtained when the wide-angle lens attachment 3 is not attached (see FIG. 5A), the pixels formed based on the light reception signals at the respective timings in the light receiving element 25 are arranged in chronological order (that is, the main scanning order). In a row from left to right. Each column is arranged from top to bottom in time series order (that is, corresponding to the order of sub-scanning). On the other hand, when the reversing process by the control unit 100 is performed, in the mounted state of the wide-angle lens attachment 3, the pixels formed based on the light reception signals at the respective timings in the light receiving element 25 are arranged in chronological order (ie, main Corresponding to the scanning order), they are lined up from right to left. Each column is arranged from the bottom to the top in time series order (that is, corresponding to the sub-scanning order). As a result of the processing, it is possible to match the correspondence between the top and bottom, left and right of the image and the top and bottom and left and right of the fundus in the mounted state and the non-mounted state of the wide-angle lens attachment 3.

  In the first embodiment, image processing for inverting the image vertically and horizontally is performed on an inverted fundus image obtained with the wide-angle lens attachment attached. In the first embodiment, image processing is performed according to the detection result by the sensor 8. As described above, the sensor 8 detects whether or not the wide-angle lens attachment 3 is attached to the main body 2. For example, when the control unit 100 receives a signal output from the sensor 8 when the wide-angle lens attachment 3 is attached, the control unit 100 performs image processing for inverting the top / bottom / left / right of the image. In the first embodiment, as a result of image processing, an upright image can be obtained for a fundus image captured at a wide angle of view. Therefore, an erect image of the fundus image can be obtained regardless of whether or not the wide-angle lens attachment 3 is attached.

  In the first embodiment, the case where the above-described image processing is performed as the inversion processing will be described, but the present invention is not necessarily limited thereto. For example, instead of inverting the top / bottom / left / right of the once formed fundus image, a fundus image in which the top / bottom / left / right is inverted in advance may be generated. The inversion process may be an inversion process by software or an inversion process by hardware (for example, an inversion processing circuit using an electric circuit).

  In addition, the control unit 100 performs display control for displaying the sequentially generated fundus image on the monitor 50 as a live image. For example, in the first embodiment, when the wide-angle lens attachment 3 is attached to the main body unit 2, the control unit 100 displays the fundus image inverted by the above image processing on the monitor 50 as a live image. To do. On the other hand, when the wide-angle lens attachment 3 is not attached, the control unit 100 displays the fundus image that has not undergone the reversal process on the monitor 50 as a live image. The inversion process may be performed when displaying not only a live image but also a still image of the fundus generated by the apparatus main body 2.

  Next, a second embodiment of the present disclosure will be described with reference to FIG. In the description of the second embodiment, the same reference numerals as those of the first embodiment are used for the same configurations as those of the first embodiment, and the description thereof is omitted. In the second embodiment, the fundus imaging apparatus 1 is equipped with a wide-angle lens attachment 3 having a lens configuration different from that of the first embodiment. As a result, the fundus imaging apparatus 1 of the second embodiment has a better configuration when imaging a fundus image using a plurality of colors of laser light. For example, in the second embodiment, the fundus imaging apparatus 1 outputs a light beam in which three types of monochromatic light of red, green, and blue are combined from the laser light emitting unit 11 and captures a color image of the fundus. It may be a configuration. In this case, the light receiving optical system 20 of the fundus photographing apparatus 1 may be provided with a light receiving element having sensitivity to each monochromatic light, and light of each wavelength is received by the corresponding light receiving element. Thus, a configuration (for example, a dichroic mirror or the like) that branches the optical path may be provided as appropriate.

  In the configuration in which an image is formed based on light having a plurality of wavelengths as described above, the chromatic aberration of magnification of a lens included in the optical system of the apparatus becomes a problem. In contrast, the wide-angle lens attachment 3 shown in FIG. 6 is provided with a magnification chromatic aberration correction lens 133. The lateral chromatic aberration correction lens 133 suppresses at least lateral chromatic aberration of the laser light generated by the second objective optical system 31. The lateral chromatic aberration correction lens 133 may be an achromatic lens formed by bonding two or more lenses having different refractive indexes and different light dispersions (Abbe numbers). For example, in the example of FIG. 6, the magnification chromatic aberration correction lens 133 is formed by laminating a flint glass-made concave lens 133a and a crown glass convex lens 133b. The number of lenses forming the magnification chromatic aberration correction lens 133 may be determined according to the number of colors included in the laser light. For example, the chromatic aberration correction lens 133 of FIG. 6 can align the light condensing position of two of the three colors included in the laser light with the condensing position of the other one color. Therefore, in the example of FIG. 6, the influence of lateral chromatic aberration on the fundus image obtained by the apparatus is suppressed.

  In addition, it is preferable that the magnification chromatic aberration correction lens 133 has a power of 0 (that is, the sum of the powers of the concave lens 133a and the convex lens 133b is 0). In this case, the magnification chromatic aberration correction lens 133 hardly affects the inclination and height of the light beam. Therefore, the presence / absence of the magnification chromatic aberration correction lens 133 hardly affects the design of the second objective optical system 31.

  In the example of FIG. 6, the lateral chromatic aberration correction lens 133 is disposed between the inspection window 17 of the main body 2 and the first turning point P in the mounted state of the wide-angle lens attachment 3, and the wide-angle lens attachment 3. An incident window for laser light is formed. Thereby, even if it does not provide a cover glass etc. as an entrance window of the wide-angle lens attachment 3, the wide-angle lens attachment 3 can be dust-proof. Of course, the magnification chromatic aberration correction lens 133 may be arranged away from the incident window.

  Next, a third embodiment of the present disclosure will be described with reference to FIG. The fundus photographing apparatus 1 in the third embodiment is different from the second objective optical system 31 in the first and second embodiments in the lens configuration of the second objective optical system 230 provided in the objective lens attachment 3. In the description of the third embodiment, the same reference numerals as those of the second embodiment are used for the same configurations as those of the second embodiment, and the description thereof is omitted.

  The wide-angle lens attachment 3 of the third embodiment includes a second objective optical system 230. Similarly to the second embodiment, the wide-angle lens attachment 3 of the third embodiment may include a diopter correction lens 32 and a magnification chromatic aberration correction lens 133 as shown in FIG.

  The second objective optical system 230 in the third embodiment includes a first objective lens 231 and a second objective lens 232 in order from the one arranged near the eye to be examined (see FIG. 7). In the third embodiment, the first objective lens 231 and the second objective lens 232 are arranged adjacent to each other. In the example of FIG. 7, the first objective lens 231 and the second objective lens 232 are both lenses having positive power. In the mounted state of the wide-angle lens attachment 3 in the third embodiment, the lenses 231 and 232 are directed toward the optical axis L3 of the second objective optical system 230 at a position higher than the chief ray height of the laser light in the inspection window 30. Used to bend the laser beam.

  In the third embodiment, the first objective lens 231 is an aspheric lens. The first objective lens 231 corrects the spherical aberration of the image at the second turning point Q (that is, the turning point formed by the second objective optical system 230).

  In general, in a scanning laser ophthalmoscope, an objective optical system (for example, an objective optical system 16, 31, 230, etc.) that bends a laser beam as in the present disclosure in order to turn the laser beam at the anterior eye part and guide it to the fundus. ) Is required between the scanning unit and the eye to be examined. In this case, the laser light is accurately passed through one point (turning point) of the anterior eye part (for example, the pupil), and the laser light is turned so that the non-mydriatic (that is, the mydriatic agent is not instilled). It is possible to photograph the fundus at a wide angle of view with respect to the subject's eye. Here, in order to guide the laser beam bent by the objective optical system well into the eyeball, it is important to suppress the spherical aberration of the image at the turning point. That is, by suppressing the spherical aberration, it becomes difficult for the laser light to be vignetted by the pupil. This spherical aberration is more likely to occur as the light beam is bent at a steep angle by the objective optical system, that is, as the field angle for photographing is larger. For example, in the case of securing a field angle of 90 ° or more in all angles, if it is attempted to suppress the spherical aberration of image formation at the turning point by using only a spherical lens, a plurality of spherical lenses are required. It becomes complicated. In addition, if the spherical aberration of the image formed at the turning point is large, the laser beam is easily vignetted at the pupil of the eye to be examined. As a result, an allowable alignment range (that is, an allowable range of position adjustment between the eye to be examined and the apparatus) in which a fundus image with uniform brightness can be obtained becomes narrow.

  In contrast, in the third embodiment, the spherical aberration of image formation at the second turning point Q (that is, the turning point formed by the second objective optical system 230) is caused by the first objective lens 231 that is an aspheric lens. It is suppressed. As a result, for example, the objective optical system 230 that favorably suppresses spherical aberration can be formed with a smaller number of lenses. In addition, with the suppression of spherical aberration, the laser light becomes less vignetting at the pupil, so the alignment tolerance is widened. As a result, a fundus image with uniform brightness can be easily obtained.

  As shown in FIG. 7, the first objective lens 231 may have at least a lens surface 231a on the light source side formed as an aspherical surface. In this case, the lens surface 231a is formed as a curved surface having a radius of curvature that increases as the position is away from the optical axis L3 of the first objective lens 231 in order to reduce spherical aberration.

  On the other hand, the eye-side lens surface 231b of the first objective lens 231 may be formed as a flat surface. As a result of examination by the present inventors, the larger the radius of curvature of the eye side lens surface 231b, the larger the distance w between the eye side lens surface 231b (where the lens surface 231b is closest to the eye side to be examined) and the turning point Q. It has been confirmed that it is easy to secure a long time. In the example of FIG. 7, the eye side lens surface 231b to be examined is a flat surface, and its radius of curvature is infinite. Therefore, it is easy to design an optical system that can obtain a sufficient interval w. As described above, as a result of forming the eye side lens surface 231b with a sufficiently large radius of curvature, a working distance (for example, an interval between the examination window 30 and the corneal apex) is easily secured. Thereby, for example, the examinee or his / her assistant or the like can easily open the subject (uplifting the upper eyelid with a finger or the like). Note that in the design solution of the optical system of FIG. 7 by the present inventor, it was possible to secure an interval w of about 13 mm while ensuring a field angle of 100 ° or more. Here, assuming that the inspection window 30 is also used by the lens surface 231b, and the working distance is a value obtained by subtracting about 3 mm, which is a typical distance from the corneal apex of the human eye to the pupil, from the interval w. About 10 mm can be secured.

  As an example, the case where the eye side lens surface 231b is formed as a flat surface has been described. However, the present invention is not limited to this, and the eye side lens surface 231b may be formed as a curved surface having a sufficiently large radius of curvature. . In this case, the eye side lens surface 231b to be examined may be either a concave surface or a convex surface. Whether the eye-side lens surface 231b is formed of a concave surface or a convex surface, it is desirable that the eye side lens surface 231b be formed with a radius of curvature of 10 times or more with respect to the intended working distance. In this case, as a result, the design of the second objective optical system 230 capable of obtaining the desired working distance is facilitated. For example, as shown in FIGS. 8A and 8B, when the eye-side lens surface 231b is designed with a radius of curvature of about 80 mm, it is easy to design a working distance of about 8 mm ( That is, w can be set to about 11 mm). The eye side lens surface 231b to be examined may be either a spherical surface or an aspherical surface. However, the larger the angle of view that can be photographed, the easier the shape of the light source side lens surface 231a of the first objective lens 231 deviates from the spherical surface. For this reason, as a manufacturing method of the 1st objective lens 231, it is thought that aspherical surface creation by cutting is easy to be adopted. Therefore, in order to reduce the processing cost of the lens, as shown in the third embodiment, the eye side lens surface 231b is preferably formed in a planar shape that does not require cutting.

  In the third embodiment, the second objective lens 232 is a cemented lens that corrects (suppresses) lateral chromatic aberration generated in the second objective optical system 230 for at least two colors of laser light having different wavelengths. More specifically, the second objective lens 232 suppresses (reduces) lateral chromatic aberration caused by the second objective optical system 230 with respect to the three colors of red, green, and blue laser light emitted from the light source 11. The second objective lens 232 has a positive power as a whole and bends the laser light. As shown in FIG. 7, the second objective lens 232 moves laser light incident on the second objective lens 232 away from the optical axis L3 closer to the optical axis L3 (for example, toward the optical axis L3). Bend it.

  Here, in the third embodiment, the second objective optical system 230 is a refractive optical system that refracts and bends the laser light. In the third embodiment, the second objective optical system 230 has an angle of view of 90 ° or more. Bend the laser beam greatly to ensure. In general, the greater the fold of the light beam at the refractive elements (eg, lenses and prisms), the greater the chromatic aberration of magnification that can occur. In the third embodiment, in order to satisfactorily perform the above association, the laser light emitted from the laser light emitting section 11 is emitted from two or more colors (in the third embodiment, red, green, and blue). It is important to correct (suppress) the lateral chromatic aberration caused by the second objective optical system 230.

  In contrast, in the third embodiment, the second objective optical system 230 is provided with the second objective lens 232 that is a cemented lens, so that the laser beam is largely bent so that an angle of view of 90 ° or more can be obtained. In addition, the lateral chromatic aberration caused by the second objective optical system 230 with respect to the three colors of red, green, and blue laser light is suppressed. As a result, in the fundus imaging apparatus 1 of the third embodiment, it is easy to obtain a color fundus image with good colors.

  Note that it is not necessary for the second objective lens 232 to correct all the chromatic aberration of magnification that occurs when the wide-angle lens attachment 3 is attached. Similarly to the second embodiment, the lateral chromatic aberration correction lens 133 may be used together to correct the lateral chromatic aberration. In this case, for example, a chromatic aberration correction lens 133 having a power of 0 (that is, the sum of the powers of the concave lens 133a and the convex lens 133b is 0) may be used.

  The second objective lens 232 is formed by bonding a concave lens 232a and a convex lens 232b. In the example of FIG. 7, a plano-concave lens is used as the concave lens 232a, and a biconvex lens is used as the convex lens 232b. The second objective lens 232 is formed by bonding the concave surface of the concave lens 232a and one convex surface of the convex lens 232b. However, the specific shapes of the concave lens 232a and the convex lens 232b forming the second objective lens 232 are not limited to this. In the third embodiment, the concave lens 232a and the convex lens 232b constituting the second objective lens 232 have different light dispersions (Abbe numbers). Such a second objective lens 232 suppresses lateral chromatic aberration that occurs when the light beam is largely bent by the second objective optical system 230.

  In the second objective lens 232 in FIG. 7, a concave lens 232a is disposed on the eye side to be examined with respect to the convex lens 232b. However, in the second objective lens 232, the arrangement of the concave lens 232a and the convex lens 232b may be reversed with respect to the example of FIG. That is, the concave lens 232a may be disposed on the light source side with respect to the convex lens 232b.

  Here, referring to FIG. 9, when the concave lens 232a is arranged on the eye side to be examined with respect to the convex lens 232b (see FIG. 9A), the concave lens 232a is arranged on the eye side to be examined with respect to the convex lens 232b. (See FIG. 9B). The optical system shown in FIG. 9A is a simplified illustration of the structure of the objective lens attachment 3 shown in FIG. Further, the optical system shown in FIG. 9B is designed with a design solution in which the interval w and the angle of view are the same as those of the optical system shown in FIG. Therefore, it is assumed that the designs of the lenses denoted by the same reference numerals in FIGS. 9A and 9B do not necessarily match. 9A and 9B, H represents the position of the front principal point in the second objective optical system 230, H ′ represents the position of the rear principal point, and F represents the focal position. Yes.

  As shown in FIG. 9, when the direction of the second objective lens 232 is reversed, the positions of the main points H and H ′ change. In the example of FIG. 9, when the concave lens 232 a is arranged on the eye side to be examined with respect to the convex lens 232 b (see FIG. 9A), compared to the case where the concave lens 232 a is arranged on the light source side with respect to the convex lens 232 b. The positions of the points H and H ′ can be moved away from the second turning point Q as a whole. As a result, the paraxial imaging magnification from the first turning point P to the second turning point Q can be smaller in the example of FIG. 9B than in the example of FIG. 9A. For example, in one design solution by the present inventor, about 0.414 (times) is obtained as the value of the imaging magnification in the example of FIG. 9A, and the above result in the example of FIG. 9B is obtained. As a value of image magnification, about 0.374 (times) was obtained.

  Thus, even when the interval w and the angle of view are the same, the imaging magnification varies depending on the design solution of the second objective optical system 230. The difference in imaging magnification is that the degree of satisfaction of the sine condition (the condition that satisfies the coma aberration when the spherical aberration is satisfied) is different between the example of FIG. 9A and the example of FIG. 9B. This is probably because of this. The larger the imaging magnification value, the lower the light density of the laser light in the cornea, so that the burden on the eye to be examined due to the laser light is suppressed. Here, the light density is proportional to the square of the imaging magnification. Therefore, for example, the imaging magnification in the example of FIG. 9A is about 0.414 (times), and the imaging magnification in the example of FIG. 9B is about 0.374 (times). In some cases, the light density in the example of FIG. 9B is approximately 1.2 times that in the example of FIG. Thus, the light density of the laser light in the cornea is lower in the example of FIG. 9A than in the example of FIG. 9B. Therefore, it can be considered that the example of FIG. 9A can be relatively photographed while suppressing the burden on the eye to be examined.

  Further, as shown in FIG. 9, the direction of the second objective lens 232 is reversed, so that the position of the focal point F in the second objective lens optical system 230, that is, the fundus conjugate position of the eye E to be examined is different. I understand that. More specifically, in FIG. 9A, the focal point F is located farther from the lens surface of each lens constituting the second objective optical system 230 than in FIG. 9B. By the way, in the fundus oculi photographing device 1, the light reflected by the lens surface in each lens of the light projection optical path is removed by the confocal stop (in the third embodiment, the pinhole plate 23, see FIG. 1). In this case, the light reflected from the lens surface becomes confocal as the fundus conjugate position is further away from the lens surface (for example, the light source side lens surface of the second objective lens 232) that reflects the laser light toward the light source. It is efficiently removed by the diaphragm. Therefore, the example of FIG. 9A can obtain a good fundus image with relatively little noise.

  On the other hand, as the imaging magnification value is smaller, the laser light emitted from the second objective optical system 230 to the eye to be examined is collected in a narrower range at the second turning point Q. As a result, compared to the example of FIG. 9A, it is considered that the example of FIG. 9B is less likely to cause vignetting of the laser light applied to the eye to be examined. Therefore, the example of FIG. 9B is considered to be suitable for photographing an eye with a relatively small pupil diameter.

  As described above, in the third embodiment, the first objective lens 231 that is an aspherical lens and the second objective lens 232 that is a cemented lens are arranged in combination, so that the second objective optical system 230 can be easily configured. In this way, a good fundus image can be captured. For example, a fundus image having a wide field angle of 90 ° or more can be obtained favorably with a non-mydriatic pupil. In addition, a good fundus image in which the influence of chromatic aberration of magnification is suppressed can be obtained even in multicolor light photography such as color photography. In addition, a good working distance can be secured.

  As mentioned above, although demonstrated based on embodiment, the said embodiment can be variously deformed.

  For example, in the above-described embodiment, a case has been described in which image processing is performed to invert the fundus image vertically and horizontally according to the wearing state of the wide-angle lens attachment 3 detected by the sensor 8. However, it is not necessarily limited to this. For example, a first control mode in which a live image is displayed using an image that has been subjected to image processing for inverting the top / bottom / left / right of the image, and a second control that displays an image using an image that has not been subjected to the image processing. The control mode may be configured to be switched based on an instruction from the examiner. For example, when a mode switching signal output based on a mode switching operation on an operation unit (not shown) is received, the control unit 100 may display a live image in a control mode corresponding to the mode switching signal.

  In each of the above embodiments, the second objective optical systems 33 and 230 have been described as being provided in the wide-angle lens attachment 3 that can be attached to and detached from the apparatus main body 2 with the first objective optical system 16 provided. It is not necessarily limited to this. For example, the fundus imaging apparatus 1 may be an apparatus in which a lens attachment including the second objective optical systems 33 and 230 is attached to the apparatus main body in exchange for a lens unit including the first objective optical system 16. Even in this case, the second objective optical systems 33 and 230 can photograph a fundus image having a wide angle of view satisfactorily.

  As illustrated in FIG. 10, in this case, a relay optical system such as a relay lens is provided between the scanning unit 25 and the second objective optical system (the second objective optical system 230 in FIG. 10). It may be. In FIG. 10, the optical system disposed between the second objective optical system 230 and the scanning unit 25 is an example of the relay optical system 300. In FIG. 10, the relay optical system includes a plurality of lenses (lenses 301 and 302), and guides the laser light reflected by the scanning unit 25 to the second objective optical system 230. Note that the shape and arrangement of the lenses shown in FIG. 10 are for convenience of explanation.

  In the third embodiment, an aspherical lens (first objective lens 231) is disposed as the lens closest to the eye to be examined in the second objective optical system 230, and the eyeside lens surface (lens surface 231b) of the aspherical lens is arranged. ) Is formed with a radius of curvature greater than 10 times the working distance. However, in the objective optical system (for example, the second objective optical system) provided in the wide-angle lens attachment, if the lens surface located closest to the eye to be examined is formed with a surface having a radius of curvature of 10 times or more of the working distance. Well, the lens on which the lens surface is formed is not necessarily limited to an aspheric lens. For example, it may be a spherical lens (for example, the first objective lens 31a of the first and second embodiments) or a cemented lens. Even in these cases, it is considered that the design that facilitates securing the working distance may be facilitated.

  Also, the wide-angle lens attachment 3 of the first embodiment and the second embodiment may have a cemented lens for suppressing lateral chromatic aberration generated in the second objective optical system 31 as in the third embodiment. . For example, as illustrated in FIGS. 3 and 6, as an example, in the first and second embodiments, the wide-angle lens attachment 3 is provided with a third objective lens 31 c that is a cemented lens. By appropriately forming the concave lens and the convex lens of the cemented lens with materials having different light dispersions (Abbe numbers), the chromatic aberration of magnification generated in the second objective optical system 31 can be suppressed by the third objective lens 31c. Of course, the present invention is not limited to the configuration shown in FIGS. 3 and 6, and the mode of the cemented lens can be changed as appropriate.

  In the above-described embodiment, the case where the imaging field angle of the scanning laser ophthalmoscope is widened by the wide-angle lens attachment has been described, but the present invention is not necessarily limited thereto. For example, the technology disclosed in the embodiments can be applied to, for example, an optical coherence tomography (OCT) that is a kind of fundus imaging apparatus. The optical coherence tomometer splits the light beam emitted from the light source into a laser beam and a reference beam, guides the laser beam to a predetermined part of the eye to be examined, guides the reference light beam to the reference optical system, and then at a predetermined part of the eye to be examined. It has an interference optical system that causes the light receiving element to receive interference light obtained by combining the reflected laser beam and the reference beam. The optical coherence tomography has a scanning unit that scans a laser beam on the fundus.

DESCRIPTION OF SYMBOLS 1 Fundus photographing apparatus 2 Main body part 3 Wide angle lens attachment 15 Scan part 31 2nd objective optical system 230 2nd objective optical system 231 1st objective lens 231a Light source side lens surface 231b Test object side lens surface 232 2nd objective lens 232a Concave lens 232b Convex lens E Eye to be examined P First turning point Q Second turning point

Claims (11)

A light source that emits at least a laser beam having a first wavelength and a laser beam having a second wavelength different from the first wavelength, and a laser beam for scanning the fundus of the laser beam emitted from the light source. A scanning unit that changes the traveling direction, and an objective optical system that is disposed between the eye to be examined and the scanning unit, and that forms a turning point where the laser light guided from the scanning unit is swung in accordance with the operation of the scanning unit. And a fundus imaging apparatus that captures an image of the fundus of the eye to be examined using light from the fundus of the laser beam guided to the eye fundus through the turning point,
The objective optical system is configured to bend the laser light guided from the scanning unit toward the optical axis of the objective optical system, thereby making the scanning range of the laser light on the fundus 90 ° or more in full angle,
The objective optical system further includes at least a cemented lens that corrects lateral chromatic aberration generated in the objective optical system with respect to at least the first wavelength laser beam and the second wavelength laser beam. .   2. The fundus imaging apparatus according to claim 1, wherein the cemented lens is formed by bonding a concave lens and a convex lens, each of which has different material dispersions, one by one.   The fundus imaging apparatus according to claim 2, wherein the cemented lens has a concave lens disposed on the eye side to be examined with respect to the convex lens.   The fundus imaging apparatus according to claim 2, wherein the cemented lens has a convex lens disposed on the eye side to be examined with respect to the concave lens.   In the objective optical system, an aspheric lens that suppresses the spherical aberration of image formation in the rotation is arranged on the most eye side in the objective optical system by forming at least one lens surface in an aspheric shape. The fundus photographing apparatus according to claim 1, wherein the fundus photographing apparatus is provided as a lens.   6. The one lens surface formed in an aspherical shape in the aspherical lens is formed in a curved surface such that a radius of curvature becomes larger as a position away from the optical axis of the aspherical lens. 8. A fundus imaging apparatus according to any one of items 1 to 7. The objective optical system includes only the aspheric lens and the cemented lens,
The laser beam from the scanning unit is bent by the aspherical lens and the cemented lens from the position having the highest light beam height to the optical axis side of the objective optical system. Fundus photographing device.   In the objective optical system, the eye-side lens surface formed closest to the eye to be examined is a surface having a radius of curvature of 10 times or more of the working distance. Fundus photographing device.   The fundus imaging apparatus according to claim 8, wherein the eye side lens surface of the aspheric lens is formed into a flat surface. It has a wide-angle lens attachment that can be attached to and detached from the subject-side casing surface of the fundus imaging apparatus,
The fundus imaging apparatus according to claim 1, wherein the objective term optical system is provided in the wide-angle lens attachment. A light source emitting at least a laser beam having a first wavelength and a laser beam having a second wavelength different from the first wavelength, and a traveling direction of the laser beam for scanning the fundus of the laser beam emitted from the light source A first objective that forms a first turning point that is disposed between the scanning unit that changes the position of the eye and the eye to be examined and the scanning unit, and the laser light guided from the scanning unit is turned in accordance with the operation of the scanning unit. A subject-side side of a fundus imaging apparatus that captures an image of the fundus of the subject's eye using light from the fundus of the laser beam guided to the subject's fundus through the first turning point. A wide-angle lens attachment that is mounted on a housing surface and widens the angle of view of the fundus image,
In a mounting state in which the attachment is mounted on the housing surface having the inspection window, a second turning point is formed in which the laser light that has passed through the first turning point is further turned in accordance with the operation of the scanning unit. An objective optical system is provided,
The second objective optical system includes at least a cemented lens that corrects at least a lateral chromatic aberration generated in the first objective optical system with respect to the laser light of the first wavelength and the laser light of the second wavelength. Lens attachment.