JP7435961B2 - fundus imaging device - Google Patents

Description

The present invention relates to a fundus photographing device for photographing a fundus image of an eye to be examined, and particularly to a fundus photographing device that can easily set an appropriate focus position for the eye to be examined.

In a fundus imaging device such as a scanning laser ophthalmoscope (SLO), a pinhole plate is provided in a light-receiving optical system at a position conjugate with the fundus, and light passing through the pinhole is received by a light-receiving element. When photographing the fundus, focus is adjusted so that the fundus image becomes the brightest (see, for example, Patent Document 1). In recent years, there has been an increasing demand for fundus imaging devices with a wide angle of view, but in this type of wide-angle fundus imaging device, the diameter is large enough to cover the maximum amount of aberration due to the large amount of aberration in the light receiving optical system. A pinhole is required.

However, when the diameter of the pinhole is large, there is a problem that the brightness of the fundus observation image changes slowly during focus adjustment, making it difficult to find an appropriate focus position.

JP2019-103746A

The present invention has been made in view of the problems of the background art described above, and an object of the present invention is to provide a fundus photographing device that can easily and accurately set an appropriate focus position for an eye to be examined.

A fundus photographing device for achieving the above-mentioned object has a light projecting optical system and a light receiving optical system, and includes a fundus photographing system that photographs the fundus of an eye to be examined using scanning light, and the fundus photographing system has an operating mode. It has a switching mechanism that changes the diameter of the light-receiving pinhole provided at the conjugate position of the fundus of the light-receiving optical system in accordance with this.

In the fundus photographing apparatus described above, by using light receiving pinholes with different diameters depending on the operating mode in the light receiving optical system, it is possible to obtain a fundus image with accuracy depending on the operating mode. Thereby, it is possible to detect an appropriate focus position using an appropriate image and to perform accurate fundus photography.

According to a specific aspect of the present invention, in the fundus photographing device described above, the operation mode includes a fundus observation mode for observing the fundus, a focus adjustment mode for focus adjustment, and a fundus photographing mode for photographing the fundus. In the fundus observation mode and the fundus photography mode, the switching mechanism is switched so that at least a large-diameter light receiving pinhole is arranged on the optical path of the light receiving optical system, and in the focus adjustment mode, at least a large diameter light receiving pinhole is arranged on the optical path of the light receiving optical system. It is switched so that a small-diameter light-receiving pinhole is arranged. In this case, in the focus adjustment mode, by using a small-diameter light-receiving pinhole with a large confocal effect, changes in the brightness of the fundus image are made more sensitive, making it easier to detect an appropriate focus position. In particular, an appropriate focus position can be easily detected in a wide-angle fundus photographing device that requires a large light-receiving pinhole.

According to another aspect of the present invention, the focus adjustment mode includes a coarse focus adjustment mode regarding coarse focus adjustment and a fine focus adjustment mode regarding fine focus adjustment, and the switching mechanism is configured to operate in coarse focus adjustment mode. In the mode, a large-diameter light-receiving pinhole is placed on the optical path of the light-receiving optical system, and in the fine focus adjustment mode, a small-diameter light-receiving pinhole is placed on the optical path of the light-receiving optical system. . In this case, the focus position can be detected efficiently by adjusting the focus in two stages, coarse movement and fine movement, using appropriate images.

According to yet another aspect of the present invention, the fundus observation mode is used for alignment performed before the fundus photography mode. By performing alignment using a fundus image with a brightness suitable for alignment, alignment can be performed efficiently.

According to still another aspect of the present invention, there is provided a control device that controls the operation of the fundus imaging system, and the switching mechanism operates under the control of the control device to switch the light receiving pinhole. In this case, the light-receiving pinholes can be efficiently switched at the required timing in accordance with the operation mode.

According to still another aspect of the present invention, the control device is configured to move the light emitting focus lens provided in the light emitting optical system and the light receiving focus lens provided in the light receiving optical system in a focus adjustment mode related to focus adjustment. Then, the position where the brightness of the fundus image obtained by the fundus imaging system has the maximum value is determined to be the optimal focus position. In this case, the focus position can be easily detected based on the brightness of the fundus image.

FIG. 1 is a side view illustrating a fundus photographing device according to a first embodiment. 2 is a conceptual diagram mainly explaining the optical structure of the fundus photographing device shown in FIG. 1. FIG. (A) is a plan view illustrating a large-diameter light-receiving pinhole, and (B) is a plan view illustrating a small-diameter light-receiving pinhole. It is a figure showing a monitor display at the time of fundus photography. It is a flowchart explaining the operation of the fundus photographing device. FIG. 3 is a diagram illustrating brightness adjustment of a fundus image. It is a flowchart explaining the operation of fundus photography. It is a conceptual diagram explaining the fundus photographing device of a 2nd embodiment. (A) and (B) are diagrams illustrating modified examples of the light receiving pinhole.

[First embodiment]
Hereinafter, a fundus photographing apparatus 200 according to a first embodiment of the present invention will be described with reference to FIG. 1 and the like.

The fundus photographing device 200 includes an optical unit section 201, a chin rest section 203, and a mount section 205. The optical unit section 201 includes, in a housing 201a, a fundus imaging system 100 for observing the fundus of the eye to be examined EY, as well as various mechanisms including a control circuit, a drive device, etc. (not shown). The optical unit section 201 is supported by a stage 301, and the stage 301 can be moved three-dimensionally together with the optical unit section 201 by a drive mechanism 302.

In the optical unit section 201, a monitor 201c is provided at the upper side of the side facing the operator, and the operator can visually view observation images of the fundus and other objects, control information regarding the imaging operation, and the like.

The chin rest part 203 is attached to face the side surface of the optical unit part 201 on the subject side. Although a detailed explanation is omitted, the chin rest part 203 has a plurality of abutting parts for fixing the chin and forehead of the subject, and by adjusting the arrangement of the plurality of abutting parts, the subject's eye EY can be adjusted. The height of the subject's eye can be adjusted and fixed relative to the optical unit section 201 so as to face the objective lens section 201e of the fundus photographing system 100.

The pedestal section 205 supports the optical unit section 201 and the chin rest section 203. An operating section 205i including operating keys and levers is provided on the upper surface of the operator side portion of the gantry section 205, and the operator can control the operating state of the fundus photographing device 200 while observing the monitor 201c. It is now possible to do so.

FIG. 2 is a diagram illustrating the internal structure of the fundus photographing device 200 shown in FIG. 1. The fundus photographing device 200 includes a fundus photographing system 100 as a main optical system and a control device 80 as an operation control system. The fundus photographing system 100 is a main part that enables observation and photographing of the fundus EB of the eye EY to be examined using scanning light. The control device 80 performs various controls regarding the photographing operation and measurement operation of the fundus oculi photographing device 200 with respect to each part constituting the fundus oculi photographing device 200. The fundus photographing device 200 can photograph a fundus image using the fundus photographing system 100 or the like, and display the fundus image on the monitor 201c shown in FIG. Note that the fundus imaging device 200 may be configured to be integrated with other ophthalmological devices such as an optical coherence tomometer and a perimeter.

The fundus imaging system 100 is a scanning type fundus imaging unit, and includes a light projecting optical system 100a and a light receiving optical system 100b. The fundus photographing system 100 scans the fundus EB with a laser beam that is projected light ML (illumination light), and photographs a fundus image based on the reflected light RL from the fundus EB. The fundus imaging system 100 of this embodiment performs wide-angle imaging with an angle of view of 60° or more, for example. Here, for example, the angle of view of 60° means the maximum angle of view at which the fundus EB can be photographed, and corresponds to the maximum scanning angle of the projected light ML rotating on the pupil plane PS of the eye EY to be examined. The fundus photographing system 100 operates in a fundus observation mode or focus adjustment mode in which a moving image of the object is photographed when acquiring a fundus image, a color image photographing mode in which one color image is photographed, and one visible autofluorescence image. Visible autofluorescence image capture mode, visible fluorescence image capture mode that captures a single visible fluorescence image or a moving image, and near-infrared fluorescence image capture mode that captures a single near-infrared fluorescence image or a moving image. , 5 types of shooting are possible. Here, the fundus observation mode is used in initial alignment for prior position adjustment of the eye EY or fundus EB to be examined, and final alignment for fine adjustment before photographing the fundus. Further, the focus adjustment mode is used for coarse focus adjustment related to coarse focus adjustment for imaging and fine focus adjustment related to fine focus adjustment for imaging.

The projection optical system 100a of the fundus imaging system 100 includes a light source section 10, a central reflection mirror 20, a first scanning device 30, a scanning relay lens system 40, a second scanning device 50, and an objective lens system 60. has. The light receiving optical system 100b includes an objective lens system 60, a second scanning device 50, a scanning relay lens system 40, a first scanning device 30, a central reflection mirror 20, and a light receiving section 70. The objective lens system 60, the first scanning device 30, the scanning relay lens system 40, the second scanning device 50, and the central reflection mirror 20 function both as part of the projection optical system 100a and as part of the reception optical system 100b. do.

The light source section 10 of the projection optical system 100a includes a red laser 11 that emits red light, a green laser 12 that emits green light, a blue laser 13 that emits blue light, and a near-infrared laser 14 that emits near-infrared light. , a first dichroic mirror 15, a second dichroic mirror 16, a third dichroic mirror 17, a light projection lens 18, a light projection focus lens 19, and a light projection pinhole P1. The red light emitted from the red laser 11 passes through the first dichroic mirror 15 , the second dichroic mirror 16 , and the third dichroic mirror 17 , passes through the projection lens 18 and the projection focus lens 19 , and then reaches the central reflection mirror 20 . incident. The green light emitted from the green laser 12 is reflected by the first dichroic mirror 15, passes through the second dichroic mirror 16 and the third dichroic mirror 17, passes through the projection lens 18 and the projection focus lens 19, and then reaches the center. The light is incident on the reflecting mirror 20. The blue light emitted from the blue laser 13 is reflected by the second dichroic mirror 16, passes through the third dichroic mirror 17, passes through the projection lens 18 and the projection focus lens 19, and enters the central reflection mirror 20. . The near-infrared light emitted from the near-infrared laser 14 is reflected by the third dichroic mirror 17, passes through the projection lens 18 and the projection focus lens 19, and enters the central reflection mirror 20. Near-infrared light is used in fundus observation mode, focus adjustment mode, near-infrared fluorescence image capture mode, and near-infrared fluorescence image capture mode that performs continuous shooting, which will be described later, and red light included in visible light is used for color image capture. The green light contained in visible light is used in color image capture mode and visible autofluorescence image capture mode, and the blue light included in visible light is used in color image capture mode, visible autofluorescence image capture mode, and visible fluorescence image capture mode. It is used in image capture mode and visible fluorescence image capture mode that performs continuous capture.

In this embodiment, the peak wavelength of the red light emitted from the red laser 11 is, for example, 650 nm, but is preferably set within the range of 650 nm±10 nm. The peak wavelength of the green light emitted from the green laser 12 is, for example, 561 nm, but is preferably set within the range of 560 nm±10 nm. Further, the second candidate is, for example, 532 nm, but it is preferably set to any value within the range of 530 nm±10 nm. The peak wavelength of the blue light emitted from the blue laser 13 is, for example, 488 nm, but is preferably set within the range of 490 nm±10 nm. The peak wavelength of the near-infrared light emitted from the near-infrared laser 14 is, for example, 785 nm, but is preferably set within the range of 785 nm±10 nm.

The projection focus lens 19 is movable along the optical axis AX1 direction of the light source section 10, and focuses the laser light as the projection ML emitted from each of the lasers 11 to 14 onto the fundus EB of the eye to be examined EY. Adjust accordingly. That is, by adjusting the position of the light projection focus lens 19, the projected light flux is focused on the fundus EB in accordance with the diopter of the eye EY to be examined. Thereby, the position where the projected light ML is focused can be adjusted to the observation site of the fundus EB (for example, the retinal surface, etc.). Note that the light projecting focus lens 19 is interlocked with the operation of a light receiving focus lens 78 of a light receiving optical system 100b, which will be described later. The light projection pinhole P1 is provided between the light projection lens 18 and the light projection focus lens 19 and at a position conjugate with the fundus EB, and serves as a confocal diaphragm to remove unnecessary light from the light projection ML. . The light ML that has passed through the light projection lens 18 is focused on the opening of the light projection pinhole P1 and enters the light projection focus lens 19. When ejected from the collimated state, it undergoes some changes so that it becomes a divergent state or a convergent state similar to the collimated state.

The central reflection mirror 20 has a reflection part in the central part through which the optical axis AX1 passes, and in the projection optical system 100a, the reflection part directs the projected light ML emitted from the light source part 10 in the direction of the eye to be measured EY. Fold. The projected light ML whose direction has been changed by the central reflection mirror 20 enters the first scanning device 30 . Note that the peripheral part of the central reflecting mirror 20 is a transmitting part, and in the light receiving optical system 100b, the reflected light RL reflected by the fundus EB of the eye to be examined EY travels backward through the objective lens system 60 and the like to the central reflecting mirror 20. The light passes through the periphery of the light and enters the light receiving section 70, which will be described in detail later.

The first scanning device 30 changes the traveling direction of the projected light ML in the horizontal lateral direction corresponding to the main scan in order to scan the projected light ML on the fundus EB. The first scanning device 30 is composed of, for example, a polygon mirror. The first scanning device 30 is rotationally driven at a predetermined number of rotations by the drive unit 82 of the control device 80, and main scans the projected light ML in the lateral direction or horizontal direction (X direction) at high speed with the periphery of the optical axis AX2 as a base point. The projected light ML scanned by the first scanning device 30 enters the scanning relay lens system 40 . The polygon mirror that is the first scanning device 30 performs continuous scanning, for example, 7500 times per second.

The scanning relay lens system 40 relays the projected light ML scanned in the horizontal lateral direction by the first scanning device 30 to the second scanning device 50 . The projected light ML that has passed through the scanning relay lens system 40 is focused on the second scanning device 50 . A fundus conjugate plane EC is arranged in the middle part of the scanning relay lens system 40.

The second scanning device 50 changes the traveling direction of the projected light ML in the vertical direction corresponding to the sub-scanning in order to scan the projected light ML on the fundus EB. The second scanning device 50 is configured by, for example, a galvanometer mirror. The second scanning device 50 is driven reciprocatingly at a predetermined period by the drive unit 82 of the control device 80, and the light projection ML is directed in a vertical direction or in a direction perpendicular to the main scanning direction of the first scanning device 30 ( Perform sub-scanning at low speed in the Y direction). The projected light ML scanned by the second scanning device 50 enters the objective lens system 60 as scanning light. Between the second scanning device 50 and the pupil plane PS of the eye to be examined EY, the chief rays of the respective projected light beams having different scanning angles do not intersect on the optical axis AX2. In other words, between the second scanning device 50 and the pupil plane PS of the eye EY to be examined, the principal rays of the scanning lights or projected light beams having different scanning angles are separated from each other. This makes it possible to improve imaging accuracy with a simple lens configuration. The galvanometer mirror, which is the second scanning device 50, performs continuous scanning 13 times per second, for example, in fundus observation mode or focus adjustment mode using near-infrared light. Color image shooting mode using red light, green light, and blue light, visible autofluorescence image shooting mode using green light or blue light, single image shooting mode in visible fluorescence image shooting mode using blue light, or near-infrared light When capturing a single image in the near-infrared fluorescence image capturing mode, one scan is performed in 0.4 seconds. Further, when capturing a moving image in the visible fluorescence image capturing mode using blue light or when capturing a moving image in the near-infrared fluorescent image capturing mode using near-infrared light, scanning is performed continuously 10 times per second.

By scanning the projected light ML using two scanning devices, the first scanning device 30 and the second scanning device 50, the projected light ML scans the fundus EB of the eye EY to be examined two-dimensionally in the XY direction. It turns out. At this time, if the alignment is properly executed, the placement of the fundus imaging system 100 with respect to the eye to be examined EY will be appropriate, and the projected light ML will pass through the pupil in the pupil plane PS of the eye to be examined EY, regardless of the scanning angle. scanned as follows. In FIG. 2, the two scanning devices, the first scanning device 30 and the second scanning device 50, appear to generate scanning light by transmission, but this is an explanatory diagram; in reality, it is by reflection, that is, by the reflection mirror. Scanning light is generated by rotation and tilt.

The objective lens system 60 relays the projected light ML scanned in the horizontal and vertical directions (XY directions) by the first and second scanning devices 30 and 50 to the pupil plane PS of the eye EY to be examined. In the example shown in the embodiment, the objective lens system 60 includes a front group Gr1 and a rear group Gr2 in order from the pupil plane PS side of the eye EY to be examined, with the fundus conjugate plane EC as a boundary. By configuring the objective lens system 60 with two groups, the front group Gr1 and the rear group Gr2, the power distribution of the lens can be dispersed between the front group Gr1 and the rear group Gr2, and when viewed as the fundus imaging system 100. , the amount of movement of the projected light beam on the pupil plane PS due to different scanning angles can be suppressed. In addition, by dividing the objective lens system 60 into two groups, the front group Gr1 and the rear group Gr2, with the fundus conjugate plane EC in between, the distance from the fundus conjugate plane EC to the adjacent lens is increased, and the reflection of the objective lens surface is achieved. It is possible to prevent the harmful light generated by this from being reflected in the photographed image of the fundus EB.

In the fundus imaging system 100, since the diopter differs depending on the subject, the fundus conjugate plane EC moves within the objective lens system 60 when focusing by diopter correction. Here, as described above, the objective lens system 60 has a two-group lens configuration, and even if the fundus conjugate plane EC moves, it does not approach the lens surface located on the fundus conjugate plane EC side of each group Gr1, Gr2. This can prevent unnecessary reflected light RL and the like from the lens surface of the objective lens system 60 from passing through light receiving pinholes P2a and P2b, which will be described later. From this background, the distance between the inner lens surface of the front group Gr1 and the inner lens surface of the rear group Gr2 must be at least 0.5 times the sum of the focal lengths of the front group Gr1 and the rear group Gr2. Preferably it is 0.7 times.

The rear group Gr2 makes the principal rays with different scanning angles of the light ML from the second scanning device 50 parallel to or close to the optical axis AX2, and the front group Gr1 makes sure that the principal rays of the light ML from the second scanning device 50 are parallel to or close to the optical axis AX2. Regarding the light projection ML, chief rays having different scanning angles are made to intersect at or near the pupil plane PS of the eye EY to be examined. That is, the projected light ML that has passed through the objective lens system 60 is focused on the pupil plane PS (more precisely, the pupil) of the eye EY to be examined, and is projected onto the fundus EB. The projected light ML is in a collimated state or a state close to this before entering the subject's eye EY, but after passing through constituent elements of the subject's eye EY such as the crystalline lens and cornea, it comes into focus at the fundus EB.

The objective lens system 60 forms a turning point Q on the optical axis AX2 on the side of the eye to be examined, which is a base point at which the projected light ML that has passed through the first and second scanning devices 30 and 50 is rotated as a projected light flux by scanning. . The pivot point Q corresponds to the pupil plane PS or pupil, is on the optical axis AX2 of the objective lens system 60, and is formed at a position that is optically conjugate with the first and second scanning devices 30 and 50. The projected light flux that has passed through the first and second scanning devices 30 and 50 passes through the objective lens system 60, passes through the pivot point Q, and is irradiated onto the fundus EB. In other words, the principal ray of the projected light beam that has passed through the objective lens system 60 turns around the turning point Q as the first and second scanning devices 30 and 50 operate, and the angle of incidence changes. As a result, the projected light beam is two-dimensionally scanned on the fundus EB. By aligning the fundus photographing system 100 with respect to the eye to be examined EY, the projected light flux is focused on the pupil of the pupil plane PS, and the turning point Q is contained within the pupil of the pupil plane PS. As a result, vignetting of the projected light flux and projected light ML is suppressed, and proper fundus observation or fundus photography becomes possible.

The light receiving optical system 100b will be explained below. In the light receiving optical system 100b, the reflected light RL reflected by the fundus EB travels in the opposite direction along the same optical path as the light projecting optical system 100a to the central reflecting mirror 20. That is, the reflected light RL from the fundus EB enters the central reflection mirror 20 via the objective lens system 60, the second scanning device 50, the scanning relay lens system 40, and the first scanning device 30, and enters the central reflection mirror 20 through the transmission part of the central reflection mirror 20. The light passes through and enters the light receiving section 70. In the light receiving optical system 100b, the reflected light RL from the fundus EB is collimated by the objective lens system 60 in cooperation with elements of the eye EY such as the crystalline lens, or in a state close to this, and is collimated by the light emitting optical system 100b. The light travels backward along the same optical path as 100a and enters the light receiving section 70.

The light receiving unit 70 of the light receiving optical system 100b includes a red light receiving sensor 71 having a light receiving element that receives the red light included in the reflected light RL, and a green light receiving sensor having a light receiving element that receives the green light included in the reflected light RL. 72, a blue light receiving sensor 73 having a light receiving element that receives the blue light included in the reflected light RL, a near infrared light receiving sensor 74 having a light receiving element that receives the near infrared light contained in the reflected light RL, It has four dichroic mirrors 75, a fifth dichroic mirror 76, a sixth dichroic mirror 77, a light receiving focus lens 78, a light receiving lens 79, and light receiving pinholes P2a and P2b. The light-receiving pinholes P2a and P2b are attached so that only one can be selectively placed on the optical path, and the pinhole placed on the optical path becomes a confocal that is in a conjugate relationship with the fundus EB. Condenser lenses 71a to 74a and light receiving pinholes 71b to 74b are arranged on the optical paths of red light receiving sensor 71, green light receiving sensor 72, blue light receiving sensor 73, and near infrared light receiving sensor 74, respectively. Further, a first light shielding member 91 is arranged on the optical axis AX3 between the light receiving focus lens 78 and a pinhole arranged on the optical path among the light receiving pinholes P2a and P2b. A second light shielding member 92 is arranged on the optical axis AX3 between the pinhole arranged on the optical path and the light receiving lens 79.

A part of the reflected light RL (specifically, near-infrared light) from the fundus EB that has entered the light receiving section 70 is reflected by the fourth dichroic mirror 75, and is focused by the condensing lens 74a while passing through the light receiving pinhole. The reflected light RL that has passed through 74b enters the near-infrared light receiving sensor 74. Further, a part of the reflected light RL (specifically, blue light) passes through the fourth dichroic mirror 75, is reflected by the fifth dichroic mirror 76, and is condensed by the condensing lens 73a while being focused through the light receiving pinhole. The reflected light RL that has passed through 73b enters the blue light receiving sensor 73. Further, a part of the reflected light RL (specifically, green light) passes through the fourth dichroic mirror 75 and the fifth dichroic mirror 76, is reflected by the sixth dichroic mirror 77, and is focused by the condensing lens 72a. The reflected light RL that has passed through the light receiving pinhole 72b while being reflected is incident on the green light receiving sensor 72. Further, a part of the reflected light RL (specifically, red light) passes through the fourth dichroic mirror 75, the fifth dichroic mirror 76, and the sixth dichroic mirror 77, and is condensed by the condensing lens 71a. The reflected light RL passing through the light receiving pinhole 71b enters the red light receiving sensor 71. The light-receiving pinholes 71b, 72b, 73b, and 74b are arranged in front of the light-receiving sensors 71, 72, 73, and 74, respectively, and are located at positions conjugate with the light-receiving pinholes P2a and P2b on the optical path, which are confocal pinholes. , it is preferable that the size is optically larger than that of the light-receiving pinholes P2a and P2b.

The light receiving focus lens 78 is movable along the optical axis AX3 direction of the light receiving section 70, and adjusts the focus of the reflected light RL from the fundus EB. That is, by adjusting the position of the light-receiving focus lens 78, the out-of-focus of the fundus observation image due to the diopter of the eye EY to be examined is compensated for. Thereby, the position where the reflected light RL is focused can be adjusted on each of the light receiving sensors 71 to 74. Note that, as already explained, the light receiving focus lens 78 is linked to the operation of the light projecting focus lens 19 of the light projecting optical system 100a. Either one of the light-receiving pinholes P2a and P2b is provided between the light-receiving focus lens 78 and the light-receiving lens 79 and at a position conjugate with the fundus EB, and serves as a confocal diaphragm to remove unnecessary light from the reflected light RL. do. The reflected light RL passing through the light receiving focus lens 78 focuses on the openings of the light receiving pinholes P2a and P2b on the optical path, and enters the light receiving lens 79. The light-receiving pinholes P2a and P2b are selectively arranged on the optical path by the switching mechanism 93, so that the diameter of the pinhole can be changed by the switching mechanism 93 according to the operation mode of the fundus photographing device 200. ing. The switching mechanism 93 is, for example, a sliding mechanism including a motor, but is not limited to this.

As shown in FIGS. 3A and 3B, in this embodiment, light receiving pinholes P2a and P2b are formed in different circular pinhole plates P21 and P22, respectively. Specifically, a large diameter light receiving pinhole P2a is formed in the center of the pinhole plate P21, and a small diameter light receiving pinhole P2b is formed in the center of the pinhole plate P22. The pinhole plates P21 and P22 are set in a switching mechanism 93 shown in FIG. By switching control under the control of the control device 80, the light-receiving pinholes P2a and P2b can be efficiently switched at the necessary timing in accordance with the operation mode of the fundus photographing device 200. Moreover, between the light receiving focus lens 78 and the light receiving lens 79, a large diameter light receiving pinhole P2a or a small diameter light receiving pinhole P2b can be retractably inserted. The details will be described later, but in the fundus photography mode for photographing the fundus EB, the fundus observation mode for observing the fundus EB, and the coarse focus adjustment mode for coarse focus adjustment, a large diameter light receiving pinhole P2a is inserted on the optical path. However, in a fine focus adjustment mode regarding fine focus adjustment, a small diameter light receiving pinhole P2b is inserted on the optical path. The diameter d2 (maximum length of the hole) of the small diameter light receiving pinhole P2b is approximately 2 to 5 times the diameter d1 (maximum length of the hole) of the large diameter light receiving pinhole P2a. The shape of the light-receiving pinholes P2a and P2b is preferably circular, but may be oval or polygonal as long as it does not affect optical performance.

The first light shielding member 91 and the second light shielding member 92 arranged with the light receiving pinholes P2a and P2b in between remove unnecessary light generated by reflection of the lens surface of the front group Gr1 or the rear group Gr2 of the objective lens system 60. This is a necessary member for the role of The first light shielding member 91 located on the side of the eye to be examined EY with respect to the light receiving pinholes P2a and P2b mainly serves to block unnecessary light generated in the front group Gr1, and is located on the side of the eye to be examined EY with respect to the light receiving pinholes P2a and P2b. The second light shielding member 92 located on the opposite side mainly serves to shield unnecessary light generated in the rear group Gr2. In the present embodiment, the fundus imaging system 100 has a fundus conjugate plane EC aligned with the inner lens surface of the front group Gr1 and the rear group Gr2 when the diopter correction range of the subject's eye EY is set to ±25 diopters. Designed to avoid close proximity. Therefore, in the diopter correction range of ±25 diopters, the above-mentioned unnecessary light can be effectively blocked. Note that the light-shielding size, that is, the diameter of the first and second light-shielding members 91 and 92 is determined after considering the balance between the light-shielding effect of unnecessary light and the light-shielding (sacrifice) of reflected light RL from the fundus EB. In this embodiment, it is not chosen to completely block unnecessary light, but the sacrifice caused by blocking the reflected light RL from the fundus EB is kept to a minimum.

In the light receiving section 70, each of the light receiving pinholes 71b, 72b, 73b, and 74b is arranged at a position that is conjugate with the fundus EB of the eye EY to be examined. By guiding the reflected light RL to the light-receiving pinholes 71b, 72b, 73b, and 74b that are in a conjugate relationship with the eye to be examined EY, stray light, which is light unnecessary for measurement, generated in a region away from the fundus EB is transferred to the light-receiving pinhole 71b. , 72b, 73b, and 74b, and a fundus image with high contrast can be captured.

Between the fourth dichroic mirror 75 and the condensing lens 74a, a bandpass filter F1 that transmits only fluorescence wavelengths for near-infrared fluorescence imaging can be provided. The bandpass filter F1 can be inserted on the optical path in the near-infrared fluorescence imaging mode. Further, between the fourth dichroic mirror 75 and the fifth dichroic mirror 76, there is provided a bandpass filter F2 that transmits only the fluorescence wavelength for visible autofluorescence imaging, or a bandpass filter F2 that transmits only the fluorescence wavelength for visible fluorescence imaging. The bandpass filter F3 can be inserted in a retractable manner. In the green light autofluorescence image capturing mode, a green light bandpass filter F2 is inserted, and in the blue light autofluorescence image capturing mode or visible fluorescence image capturing mode, the blue light bandpass filter F3 is inserted. Although not shown, the bandpass filters F1 to F3 are set in a switching mechanism (not shown), and are controlled to be switched by a driving section 82 of a control device 80.

The red light-receiving sensor 71, the green light-receiving sensor 72, and the blue light-receiving sensor 73 are composed of, for example, a band-pass filter that cuts wavelengths other than the light to be received from the reflected light RL, and a light-receiving element. As the light-receiving element, for example, a high-sensitivity photodiode or the like is used. Each light receiving sensor 71, 72, 73 can obtain luminance information in the visible range for each point on the fundus EB. Based on the obtained luminance information (specifically, the output intensity of each light receiving sensor 71, 72, 73) and the scanning position information of the first scanning device 30 and the second scanning device 50, a photographed image of the fundus EB is obtained. can be formed by combining the red photographed image data obtained by the red light receiving sensor 71, the green photographed image data obtained by the green light receiving sensor 72, and the blue photographed image data obtained by the blue light receiving sensor 73, Color fundus image data can be generated by performing gamma processing or the like. In addition, in the visible autofluorescence image shooting mode using green light, the red image data obtained by the red light receiving sensor 71 and the green image data obtained by the green light receiving sensor 72 are combined and subjected to gamma processing etc. can generate visible autofluorescence image data. In the visible autofluorescence image capturing mode using blue light, visible autofluorescence image data can be generated by performing gamma processing or the like on the green captured image data obtained by the green light receiving sensor 72. In the visible fluorescence image capturing mode using blue light, visible fluorescence image data can be generated by performing gamma processing or the like on the green captured image data obtained by the green light receiving sensor 72. Note that depending on the characteristics of the dichroic mirror, each light receiving sensor may be configured without providing a bandpass filter that cuts the wavelength band.

The near-infrared light-receiving sensor 74 includes, for example, a band-pass filter that cuts wavelength bands other than near-infrared light from the reflected light RL and a light-receiving element. As the light-receiving element, for example, a high-sensitivity photodiode or the like is used. The near-infrared light receiving sensor 74 can obtain brightness information in the near-infrared region for each point on the fundus EB. A captured image of the fundus EB is formed based on the obtained luminance information (specifically, the output intensity of the near-infrared light receiving sensor 74) and the scanning position information of the first scanning device 30 and the second scanning device 50. can do. Note that depending on the characteristics of the dichroic mirror, the light receiving sensor may be configured without providing a bandpass filter that cuts the wavelength band.

As described above, the captured image data of the fundus EB captured in the near-infrared range and the captured image data of the fundus EB captured in other wavelength ranges are stored in the storage unit 83 of the control device 80 or displayed on the monitor 201c. If you have a printer installed, you can also print it out.

Although details will be described later, the fundus imaging device 200 adjusts the brightness of the fundus image in each operation mode to facilitate observation and detection. Although a detailed explanation will be omitted, when adjusting the brightness of the fundus image by inserting an ND filter or switching between a plurality of ND filters, for example, in the projection optical system 100a, the third dichroic mirror 17 and the projection lens 18 An ND filter BF that can move forward and backward under the control of the control device 80 can be provided between them, or an ND filter that can move back and forth can be provided near each of the lasers 11 to 14. Note that the ND filter may be provided in the light-receiving optical system 100b, for example, an ND filter BF that can be moved back and forth between the light-receiving lens 79 and the fourth dichroic mirror 75, or a An ND filter that can be moved forward and backward can be provided nearby.

The control device 80 includes an electronic circuit and the like that performs control processing for each part of the fundus photographing device 200 and arithmetic processing. The control device 80 includes a processing unit (CPU: Central Processing Unit) 81, a drive unit 82, a storage unit 83, and an image generation unit 84. Further, the control device 80 is provided with an input section 85 and the like.

The processing section 81 centrally controls the drive section 82, the storage section 83, the image generation section 84, and the like. The drive unit 82 controls the operations of the lasers 11 to 14, the light receiving sensors 71 to 74, and the first and second scanning devices 30 and 50, and changes the traveling direction of the projected light ML. The drive unit 82 also controls the operation of adjusting the arrangement of the light emitting lens 18, the light emitting focus lens 19, the light receiving focus lens 78, and the light receiving lens 79, and allows the operator to control the focus of the light emitting optical system 100a and the light receiving optical system 100b. adjustment based on operation or automatic focus detection, respectively. The drive unit 82 controls the operating state of the drive mechanism 302 under the operator's operation or the control of the processing unit 81, and places the fundus imaging system 100 at an appropriate three-dimensional position with respect to the eye to be examined EY. be able to. The storage unit 83 stores control programs, fixed data, temporary data, etc. for each unit. Further, the storage unit 83 stores image data acquired by the light receiving sensors 71 to 74 and composite data thereof, and stores alignment information obtained by adding additional information to the image data acquired by the light receiving sensors 71 to 74. The image generation unit 84 generates fundus image data from the light reception signals output from the light reception sensors 71 to 74. Furthermore, the image generation unit 84 generates color fundus image data and visible autofluorescence image data by combining image data of each color acquired by the light receiving sensors 71 to 73 corresponding to visible light. The monitor 201c displays information to be presented to the operator, generated fundus image data, alignment status, and the like. The input unit 85 operates in cooperation with the operation unit 205i shown in FIG. It allows you to perform settings and operations using autofocus.

FIG. 4 illustrates a fundus photographed image obtained by the fundus photographing system 100 shown in FIG. An observation image GO showing the fundus EB is displayed on the monitor 201c. In the observation image GO, by using the electronic mask MK in which the outside of the observation field of view RR is painted black, the part of the fundus observation image FU corresponding to the fundus EB is displayed brightly in a circular shape. The observation image GO is, for example, a near-infrared moving image operating in fundus observation mode or focus adjustment mode, but by changing the operation mode, it can be changed to a color image, a visible autofluorescence image, a visible fluorescence image, or a visible fluorescence image. It is also possible to switch to a moving image, a near-infrared fluorescence photographed image, a near-infrared fluorescence photographed moving image, etc.

Hereinafter, with reference to FIG. 5, a method for obtaining a fundus image using the fundus imaging device 200 shown in FIGS. 1 and 2 will be described, mainly regarding alignment in fundus observation mode and focus adjustment in focus adjustment mode. . In the fundus observation mode or focus adjustment mode, near-infrared light is emitted from the near-infrared laser 14 while the first scanning device 30 and the second scanning device 50 are continuously scanning, and a near-infrared fundus image is displayed on the monitor 201c. will be displayed live.

<Initial alignment (fundus observation mode)>
First, initial alignment of the fundus observation image is performed in the fundus observation mode under the control of the control device 80 (step S11). In the initial alignment, auto-alignment is performed in which the fundus imaging system 100 is coarsely moved three-dimensionally in the XYZ directions for positioning during fundus observation. In the initial alignment, a large-diameter light-receiving pinhole P2a is used as a pinhole provided in the light-receiving optical system 100b and having a confocal effect. By performing initial alignment using a fundus image with brightness suitable for alignment, alignment can be performed efficiently. In auto-alignment, the presence or absence of a fundus image and the area to be displayed are automatically determined.

Before the initial alignment, the subject's chin and forehead are fixed on the chin rest 203 shown in FIG. Place it so that At this time, it is also possible to align the eye EY to be examined with a certain degree of accuracy with respect to the objective lens section 201e using another optical system provided around the objective lens system 60 for alignment. This makes it easier to obtain a fundus image even at a position shifted from the initial position. As a premise of the initial alignment, the focus and other alignments regarding the fundus observation image by the fundus imaging system 100 are reset. Specifically, the light projecting optical system 100a and the light receiving optical system 100b are set in a 0 diopter state in which diopter correction is not performed. Note that if the diopter of the eye EY to be examined is known in advance and that information is input, the light emitting focus lens 19 and the light receiving focus lens 78 may be moved to the diopter correction position.

In the initial alignment, the fundus imaging system 100 is operated under the control of the control device 80, and the fundus image for alignment obtained by the fundus imaging system 100 is displayed as a moving image on the monitor 201c. A fundus observation image using near-infrared light is obtained with a pinhole plate P21 in which a large-diameter light-receiving pinhole P2a is formed inserted into the optical path. The fundus EB and the fundus photographing system 100 are aligned using a fundus image (moving image) obtained with the large-diameter light receiving pinhole P2a arranged in the light receiving optical system 100b. Specifically, under the control of the control device 80, the optical unit section 201 and the stage 301 are three-dimensionally displaced in the XYZ directions via the drive mechanism 302, so that the fundus EB of the photographed eye EY is displayed on the monitor 201c. Arrange roughly at the center or so that the brightness of the image is approximately uniform. At this time, the control device 80 gradually moves the optical unit section 201 so that the fundus image comes to approximately the center of the monitor 201c in the XY directions. Further, the control device 80 gradually moves the optical unit section 201 in a direction in which the fundus image spreads over the entire screen in the Z direction and becomes brighter. For example, if the fundus image is within a predetermined range from the reference position, it is determined that alignment is complete. In order to facilitate alignment and to use it as an alignment index, the brightness of the fundus image is adjusted to a predetermined value. FIG. 6 is a diagram illustrating brightness adjustment of a fundus image. As shown in FIG. 6, the brightness reference value (threshold value) in each operation mode is, for example, a value H1 that is about 10 to 20% lower than the value at which the brightness is maximum assuming the focus position of a standard model eye. It is set to H2. In the case of auto-alignment, specifically, the control device 80 adjusts the brightness of the fundus image to about a reference value (threshold value) H1 within a range that suppresses saturation. The brightness of the image being observed can be adjusted by directly changing the laser output using current control, etc., by inserting an ND filter BF, or by inserting an ND filter BF on the receiving optical path. , by changing the gain of the light receiving sensor.

The fundus imaging system 100 forms a fundus image as an index of the alignment state for the eye EY to be examined. If a fundus image suitable for observation cannot be obtained, the fundus imaging system 100 is configured to display the inside of the observation field of view RR with low brightness in the observation image GO shown in FIG. A fundus image or fundus observation image FU whose surroundings are partly of low brightness is displayed, or a fundus image or fundus observation image FU whose surroundings within the observation field of view RR are low brightness is displayed. It has become. Therefore, by checking the fundus image during alignment, the degree of alignment achievement can be determined. Specifically, based on the uniformity of the brightness distribution within the observation visual field RR, it is possible to determine auxiliary whether the alignment is completed or not. When automatically making a determination using the control device 80, the control device 80 determines whether the fundus is correct based on information such as the uniformity of the brightness distribution of the fundus image obtained by the fundus imaging system 100, the center of the brightness distribution, or the deviation of the center of gravity. If the uniformity of the brightness of the image is equal to or higher than a predetermined value, it is determined that the alignment for the eye EY to be examined is completed, and if the uniformity of the brightness of the fundus image is less than the predetermined value, it is determined that the alignment for the eye EY to be examined is not completed. to decide. When the fundus image within the observation field of view RR has a uniformity higher than a predetermined level, the fundus image is displayed with little deviation within the observation field of view RR, and the fundus photographing device 200 can be properly aligned with the eye to be examined EY. I can say that. As a specific method, the control device 80 determines the difference or ratio between the brightness (average value) at the center of the fundus image or fundus observation image FU and the brightness (average value) at the periphery of the image within the observation visual field RR. is within a predetermined range. When the alignment is completed, the ratio between the brightness at the center of the fundus observation image FU and the brightness at the periphery of the image is close to 1, and the allowable range of the brightness ratio is, for example, 0.5 or more. Furthermore, it is also possible to compare the brightness of images in a plurality of areas near the periphery within the observation visual field RR to determine whether the difference or ratio of brightness is within a predetermined range. In this way, if the difference or ratio of the brightness of the contrast points set in the observation field of view RR is within a predetermined range and satisfies the predetermined conditions, the control device 80 determines that the alignment is complete and starts the next process. Transition. On the other hand, if the control device 80 determines that the above predetermined conditions are not satisfied and the alignment is not completed, the control device 80 ends the auto-alignment process and displays a warning on the monitor 201c. Even in such a case, the operator can perform manual alignment by manually operating the operation unit 205i including the shooting button, etc., and can take a fundus image once the manual alignment is completed. can.

Note that the initial alignment may be performed manually by the operator. In this case, the operator operates the operation unit 205i to cause the drive mechanism 302 to perform a desired operation.

<Coarse focus adjustment (coarse focus adjustment mode)
Next, with the large-diameter light-receiving pinhole P2a arranged in the light-receiving optical system 100b, coarse autofocus is performed in the coarse focus adjustment mode under the control of the control device 80 (step S12). For example, the light emitting focus lens 19 and the light receiving focus lens 78 are moved in conjunction with each other in relatively large distance units, for example, 0.3 mm, in the directions of the optical axes AX1 and AX3, and within the range in which these lenses 19 and 78 are moved, The position where the brightness of the fundus image reaches the maximum value exceeding the reference value H1 shown in FIG. 6, for example, the brightness peak M1, is determined to be the optimal focus position L1. Thereby, the focus position can be easily detected based on the brightness of the fundus image. If the maximum brightness value is saturated or is less than the reference value H1, the brightness of the fundus image is adjusted and the maximum value is searched again. Note that while the focus lenses 19 and 78 are roughly moved in the directions of the optical axes AX1 and AX3, the focus position may be set at the midpoint between two points in the directions of the optical axes AX1 and AX3 where the average brightness of the image exceeds the reference value H1. can. Although the brightness of the image can be adjusted in the same way as in the case of initial alignment, it is preferable that the brightness adjustment by gain adjustment of the light receiving sensor 74 or the like be interrupted during focus adjustment. Further, the reference value (threshold value) H1 of image brightness may be the same value as in the case of auto alignment or a different value. Note that the coarse movement focus adjustment may be performed manually by the operator, or the coarse movement focus adjustment may be omitted depending on the result of the above-mentioned initial alignment.

<Change pinhole diameter>
After the coarse focus adjustment is completed, the switching mechanism 93 switches the large diameter light receiving pinhole P2a to the small diameter light receiving pinhole P2b under the control of the control device 80 (step S13). That is, the pinhole plate P21 in which the large-diameter light-receiving pinhole P2a is formed is retreated from the optical path, and the pinhole plate P22 in which the small-diameter light-receiving pinhole P2b is formed is inserted onto the optical path.

<Fine focus adjustment (fine focus adjustment mode)>
Next, with the small-diameter light-receiving pinhole P2b arranged in the light-receiving optical system 100b, fine autofocus is performed in the fine focus adjustment mode under the control of the control device 80 (step S14). For example, the light emitting focus lens 19 and the light receiving focus lens 78 are moved in conjunction with each other in relatively small distance units, such as 0.05 mm, in the directions of the optical axes AX1 and AX3, and within the range in which these lenses 19 and 78 are moved, The position where the brightness of the fundus image reaches the maximum value exceeding the reference value H2 shown in FIG. 6, for example, the brightness peak M2, is determined to be the optimal focus position L1. Thereby, the focus position can be easily detected based on the brightness of the fundus image. If the maximum brightness value is saturated or is below the reference value H2, the brightness of the fundus image is adjusted and the maximum value is searched again. Note that while the focus lenses 19 and 78 are slightly moved in the directions of the optical axes AX1 and AX3, the focus position can be set to a midpoint between two points in the directions of the optical axes AX1 and AX3 where the average brightness of the image exceeds the reference value H2. . Although the brightness of the image can be adjusted in the same manner as in the case of the initial alignment, it is preferable that brightness adjustment by gain adjustment of the light receiving sensor 74 or the like be interrupted during focus adjustment. Note that the reference value (threshold value) H2 of image brightness may be the same value as in the case of initial alignment or a different value. By making the brightness of the fundus image appropriate, it is possible to easily detect an appropriate focus position.

In fine focus adjustment, by using the small-diameter light-receiving pinhole P2b that can better obtain a confocal effect, it is possible to make changes in image brightness more sensitive and to facilitate detection of an appropriate focus position.

<Change pinhole diameter>
After the fine focus adjustment is completed, the small-diameter light-receiving pinhole P2b is switched to the large-diameter light-receiving pinhole P2a by the switching mechanism 93 under the control of the control device 80 at an appropriate focus position (step S15).

<Final alignment (fundus observation mode)>
Next, final alignment of the fundus observation image is performed in the fundus observation mode under the control of the control device 80 (step S16). In the final alignment, final adjustment of the alignment position between the fundus EB and the optical system is performed with the large-diameter light-receiving pinhole P2a placed in the light-receiving optical system 100b. Image brightness can be adjusted in the same way as for initial alignment. The reference value (threshold value) H1 of image brightness may be the same value as in the case of initial alignment or a different value. The final alignment may be performed manually by the operator using the operating unit 205i, but it may also be automated under the control of the control device 80. Note that the final alignment may be performed simultaneously with each fundus photography mode, or the final alignment may be omitted.

<Funus photography (fundus photography mode)>
After the final alignment is completed, a fundus image is photographed in the fundus photographing mode under the control of the control device 80 with the large-diameter light receiving pinhole P2a arranged in the light receiving optical system 100b (step S17). Specifically, after manually or automatically confirming the alignment state, the operator presses a photographing button (not shown) that constitutes the operation unit 205i, thereby switching from the fundus observation mode to the above-mentioned mode under the control of the control device 80. Switching to the fundus photography mode selected in the selection is performed. Note that the transition to fundus photography mode may be performed automatically.

Hereinafter, with reference to FIG. 7, details of fundus imaging by the fundus imaging device 200, mainly step S17 in FIG. 5, will be described. Step S22 in FIG. 7 corresponds to steps S11 to S16 in FIG. 5, and steps S23 to S27 in FIG. 7 correspond to step S17 in FIG. Note that FIG. 7 shows the color image photographing mode among the fundus photographing modes.

<Selecting mode for shooting>
First, under the control of the control device 80, the operator selects the fundus photography mode by operating the operation unit 205i via the input unit 85 (step S21). The selected fundus photography mode is recorded in the storage unit 83. In mode selection, a desired mode is selected from color image capturing mode, visible autofluorescence image capturing mode, visible fluorescence image capturing mode, and near-infrared fluorescence image capturing mode. In the visible autofluorescence imaging mode, the light source used for imaging is further selected from green light or blue light. In the visible fluorescence image capture mode and the near-infrared fluorescence image capture mode, a selection is made between single image capture and moving image capture.

When the visible autofluorescence image capturing mode is selected and green light is selected as the light source to be used, a bandpass filter F2 for green light is inserted between the fourth dichroic mirror 75 and the fifth dichroic mirror 76. Furthermore, when blue light is selected as the light source to be used, a bandpass filter F3 for blue light is inserted. When the visible fluorescence image capturing mode is selected, a bandpass filter F3 for blue light is inserted between the fourth dichroic mirror 75 and the fifth dichroic mirror 76.

<Alignment and focus adjustment>
Next, under the control of the control device 80, alignment and focus adjustment of the fundus observation image are performed (step S22). Specifically, steps S11 to S16 explained in FIG. 5 are performed.

<Color image shooting mode>
In the color image shooting mode, under the control of the control device 80, the fundus EB is irradiated with red light, green light, and blue light at the same time, and reflected light RL of each color is simultaneously received and imaged. The control device 80 generates color fundus image data by combining the obtained red photographed image data, green photographed image data, and blue photographed image data. Note that the brightness of the image can be adjusted in the same way as in the case of initial alignment. The reference value (threshold value) of image brightness may be the same value as in the case of initial alignment or a different value.

When the photographing button of the operation unit 205i is pressed to shift to the selected fundus photographing mode, the continuous scanning of the second scanning device 50 is temporarily stopped, and the second scanning device 50 moves to the photographing start position. Next, the near-infrared laser 14 is turned off, the red laser 11, the green laser 12, and the blue laser 13 are turned on simultaneously, the second scanning device 50 is operated again, and photographing of a color fundus image is started (step S23). To capture a color fundus image once, for example, 3000×3000 image data are simultaneously acquired for each of red light, green light, and blue light by scanning in the vertical direction for 0.4 seconds. The image generation unit 84 of the control device 80 synthesizes the obtained red fundus image data, green fundus image data, and blue fundus image data, and performs gamma processing or the like to generate color fundus image data (step S24). . The generated color fundus image data is stored in the storage unit 83 (step S25) and displayed on the monitor 201c (step S26).

When the photographing of the color fundus image is completed, the red laser 11, the green laser 12, and the blue laser 13 are turned off, and the driving of the first scanning device 30 and the second scanning device 50 is stopped (step S27).

Although the details are omitted, the fundus imaging device 200 also operates when a desired mode is selected from visible autofluorescence image capture mode, visible fluorescence image capture mode, and near-infrared fluorescence image capture mode in mode selection. operates according to the corresponding mode as follows under the control of the control device 80.

<Visible autofluorescence image shooting mode>
In the visible autofluorescence image photographing mode, under the control of the control device 80, the fundus EB is irradiated with light from a light source selected by mode selection among green light or blue light, and reflected light RL is received and photographed. In the case of green light, the control device 80 generates visible autofluorescence image data by combining the obtained red photographed image data and green photographed image data. In the case of blue light, the control device 80 generates visible autofluorescence image data from the obtained green photographed image data.

<Visible fluorescence image shooting mode>
In the visible fluorescence image capturing mode, under the control of the control device 80, the fundus EB is irradiated with blue light, and reflected light RL is received and imaged. The control device 80 generates visible fluorescence image data from the obtained green photographed image data.

<Near-infrared fluorescence imaging mode>
In the near-infrared fluorescence image capturing mode, under the control of the control device 80, the fundus EB is irradiated with near-infrared light, and reflected light RL is received and imaged. The control device 80 generates near-infrared fluorescence image data from the obtained near-infrared photographed image data.

In the fundus photographing apparatus 200 described above, by using the light receiving pinholes P2a and P2b of different diameters depending on the operating mode in the light receiving optical system 100b, it is possible to obtain a fundus image with accuracy depending on the operating mode. Thereby, it is possible to detect an appropriate focus position using an appropriate image and to perform accurate fundus photography.

Further, in the fine focus adjustment mode, by using the small-diameter light-receiving pinhole P2b with a large confocal effect, changes in the brightness of the fundus image are made more sensitive, making it easier to detect an appropriate focus position. In particular, an appropriate focus position can be easily detected in a wide-angle fundus photographing device that requires a large light-receiving pinhole P2a.

Note that in a narrow-angle fundus imaging device, the brightness of the entire fundus image changes sensitively with respect to focus adjustment, and the focus position where the fundus image becomes the brightest can be relatively easily recognized as appropriate. On the other hand, in a wide-angle fundus photographing device, since the amount of aberration of the light-receiving optical system 100b is large, it is necessary to set a light-receiving pinhole with a larger diameter than in a narrow-angle fundus photographing device that can cover the maximum amount of aberration. However, when the large-diameter light-receiving pinhole P2a is used during fine focus adjustment, a problem arises in that the brightness of the fundus image changes slowly, making it difficult to find an appropriate focus position. Therefore, in the fundus imaging device 200 of this embodiment, the above problem is solved by properly using pinholes with different diameters depending on the operation mode to obtain an appropriate fundus image in each operation mode.

[Second embodiment]
Hereinafter, a fundus photographing apparatus according to a second embodiment will be described. Note that the fundus photographing apparatus of the second embodiment is a modification of the fundus photographing apparatus of the first embodiment, and matters not particularly described are the same as those of the first embodiment.

As shown in FIG. 8, in the light-receiving optical system 100b of the fundus photographing device 200, the light-receiving pinholes P2a and P2b are located between the near-infrared light-receiving sensor 74 and the condensing lens 74a, instead of the light-receiving pinhole 74b. It is provided at a position conjugate with the fundus EB. In this embodiment, the light receiving pinholes P2a and P2b are not provided between the light receiving focus lens 78 and the light receiving lens 79.

Note that, in front of the red light receiving sensor 71, the green light receiving sensor 72, and the blue light receiving sensor 73, at positions conjugate with the fundus EB, a large diameter light receiving pinhole P2a is provided in place of the light receiving pinholes 71b to 73b. There is.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments. For example, the configuration of the light receiving pinholes P2a and P2b can be changed as appropriate. Specifically, as shown in FIG. 9A, a large-diameter light-receiving pinhole P2a and a small-diameter light-receiving pinhole P2b are formed in one rectangular pinhole plate P23, and the pinhole plate P21 is slid. It is also possible to have a configuration in which the Further, although not shown, instead of switching between the large-diameter light-receiving pinhole P2a and the small-diameter light-receiving pinhole P2b, a structure in which the diameter of the pinhole can be changed like a shutter or a variable aperture may be used. In addition, as shown in FIG. 9B, the pinhole plate P21 in which the large-diameter light-receiving pinhole P2a is formed is fixed, and the center axis N2 of the small-diameter light-receiving pinhole P2b is aligned with the large-diameter light-receiving pinhole P2a. The pinhole plate P22 having a small-diameter light-receiving pinhole P2b formed thereon so as to be placed over the central axis N1 may be configured to be movable.

In the above embodiment, when determining the degree of achievement of the initial alignment by checking the fundus image during the initial alignment, the observation visual field RR shown in FIG. 4 is divided into the central part and the peripheral part and the brightness ratio is calculated. However, the outer circumferential area within the observation visual field RR may be divided into 12, for example, and numbers may be assigned in a clockwise direction to determine the average brightness balance of each numbered area.

In the embodiment described above, regarding the objective lens system 60, the lens configuration shown in FIG. 2 is an example, and various lens configurations may be used.

In the above embodiment, the configurations of the light source section 10, the first scanning device 30, the second scanning device 50, the light receiving section 70, etc. illustrated in FIG. 2 are merely examples, and can be changed as appropriate.

In the embodiment described above, the light source unit 10 of the fundus photographing device 200 is configured with lasers of four wavelengths, but the number and combination of wavelengths can be changed as appropriate. For example, the light source unit 10 of the fundus photographing device 200 may be configured to have one wavelength and perform photographing using monochromatic light.

In the embodiment described above, a polygon mirror is used for the first scanning device 30 and a galvano mirror is used for the second scanning device 50, but other scanning devices such as a resonant scanner or a MEMS mirror may be used.

In the embodiment described above, in addition to the fundus imaging system 100, another optical system such as an anterior segment observation system provided around the objective lens system 60 is separately provided to perform initial alignment using the anterior segment observation image. It may be used together at the time of alignment.

In the above embodiment, the fundus imaging device 200 may be applied to optical coherence tomography (OCT) in addition to SLO, and in this case, regarding the pinhole provided at the conjugate position of the fundus of the light receiving optical system in the OCT optical system. Alternatively, pinholes with different diameters may be switched depending on the operation mode.

In the embodiment described above, the fundus imaging device 200 may be configured to be able to switch between fundus imaging with a wide angle of view and fundus imaging with a narrow angle of view in the fundus imaging mode. In this case, when shooting with a wide angle of view, the large-diameter light-receiving pinhole P2a is arranged, and when shooting with a narrow-angle of view, it is placed larger than the small-diameter light-receiving pinhole P2b used in the fine focus adjustment mode. A light-receiving pinhole with a diameter smaller than that in the wide-angle case is arranged.

11, 12, 13, 14... Laser, 10... Light source part, 15, 16, 17, 75, 76, 77... Dichroic mirror, 18... Light projection lens, 19... Light projection focus lens, 20... Central reflection mirror, 30 , 50... Scanning device, 40... Scanning relay lens system, 60... Objective lens system, 70... Light receiving section, 71, 72, 73, 74... Light receiving sensor, 71a, 72a, 73a, 74a... Condensing lens, 71b, 72b , 73b, 74b...Light receiving pinhole, 78...Light receiving focus lens, 79...Light receiving lens, 80...Control device, 81...Processing section, 82...Drive section, 83...Storage section, 84...Image generation section, 85...Input section , 91, 92... Light shielding member, 100... Fundus photographing system, 100a... Light projecting optical system, 100b... Light receiving optical system, 200... Fundus photographing device, 201... Optical unit section, 201a... Housing, 201c... Monitor, 201e... Objective Lens part, 203... Chin rest part, 205... Frame part, 205i... Operation part, 301... Stage, 302... Drive mechanism, AX1, AX2, AX3... Optical axis, EB... Fundus, EC... Fundus conjugate plane, EY... Cover Optometry, F1, F2, F3...band pass filter, FU...fundus observation image, GO...observation image, Gr1...front group, Gr2...rear group, MK...electronic mask, ML...light projection, P1...light projection pinhole, P21, P22, P23...Pinhole plate, P2a, P2b...Light receiving pinhole, PS...Pupillary plane, Q...Turning point, RL...Reflected light, RR...Observation field of view

Claims (6)

A fundus photographing system having a light projecting optical system and a light receiving optical system, and photographing the fundus of the eye to be examined using scanning light,
The fundus imaging system has a switching mechanism that changes the diameter of a light-receiving pinhole provided at a fundus conjugate position of the light-receiving optical system according to an operation mode,
The operation mode includes a fundus observation mode for observing the fundus, a focus adjustment mode for focus adjustment, and a fundus photography mode for photographing the fundus,
The switching mechanism is configured to switch so that at least a large-diameter light-receiving pinhole is arranged on the optical path of the light-receiving optical system in the fundus observation mode, and to arrange at least a large-diameter light-receiving pinhole on the optical path of the light-receiving optical system in the focus adjustment mode. A fundus imaging device that can be switched to position a small-diameter light-receiving pinhole . The fundus photographing apparatus according to claim 1, wherein the switching mechanism is switched such that at least a large-diameter light receiving pinhole is arranged on an optical path of the light receiving optical system in the fundus photographing mode. The focus adjustment mode includes a coarse focus adjustment mode for coarse focus adjustment and a fine focus adjustment mode for fine focus adjustment,
In the coarse focus adjustment mode, the switching mechanism is configured to switch such that a large-diameter light receiving pinhole is arranged on the optical path of the light receiving optical system, and in the fine focus adjustment mode, the switching mechanism is configured to dispose a large diameter light receiving pinhole on the optical path of the light receiving optical system. 2. The fundus photographing device according to claim 1 , wherein switching is made such that a small-diameter light-receiving pinhole is disposed at. The fundus imaging apparatus according to any one of claims 1 to 3 , wherein the fundus observation mode is used for alignment performed before the fundus imaging mode. comprising a control device that controls the operation of the fundus imaging system,
The fundus photographing device according to any one of claims 1 to 4, wherein the switching mechanism operates under the control of the control device and switches the light-receiving pinhole. In a focus adjustment mode related to focus adjustment, the control device controls the amount of gain obtained by the fundus photographing system within a range in which a light-emitting focus lens provided in the light-emitting optical system and a light-receiving focus lens provided in the light-receiving optical system are moved. 6. The fundus photographing apparatus according to claim 5, wherein the position where the brightness of the fundus image obtained is the maximum value is determined to be the optimum focus position.

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