JP4774261B2 - Fundus photographing device - Google Patents

Description

  The present invention relates to a fundus photographing apparatus for photographing the fundus and performing fundus observation.

2. Description of the Related Art Conventionally, a fundus apparatus that obtains a fundus image by scanning a laser beam two-dimensionally with respect to the fundus and receiving the reflection is known. In such a fundus photographing apparatus, for example, a polygon mirror and a galvanometer mirror are combined to scan a laser beam two-dimensionally on the fundus. In addition, such an ophthalmologic apparatus is known in which a confocal stop is arranged at a conjugate position with the fundus of the eye to be examined in order to increase the resolution of a captured image, thereby forming a confocal optical system (see Patent Document 1).
JP 7-171107 A

In the fundus photographing apparatus as described above, the resolution of the photographed image is increased by forming the confocal optical system, but the photographed image may become dark because the amount of received light is relatively small. For this reason, there is a demand for securing a light amount even when the resolution is lowered. On the other hand, when fluorescent photographing is performed with a confocal stop disposed, the amount of light only at the observation point increases, and the overall state may not be understood.
In view of the above-described problems of the prior art, it is an object of the present invention to provide a fundus imaging apparatus capable of adjusting the appearance of a captured image with a simple configuration.

In order to solve the above problems, the present invention is characterized by having the following configuration.
(1) In a fundus photographing apparatus for photographing a fundus of a subject eye and displaying the fundus on a monitor, the laser light is two-dimensionally scanned with respect to an optical member for condensing laser light on an observation surface of the fundus and the fundus. An irradiating optical system having a scanning unit; a photographic optical system that obtains a photographic image by receiving reflected light of the laser beam that is shared by at least a part of the irradiating optical system and reflected by the fundus; and the photographic optical system A first light beam that is detachably disposed at a position that is conjugate with the condensing point of the observation surface, and whose aperture diameter is variable in order to adjust the amount of reflected light received by the photographing optical system At least two types of beam limiting members, a limiting member and a second beam limiting member for limiting the passage of the main reflected light of the reflected light, and switching each of the at least two types of beam limiting members to the conjugate position Switching to place The switching means includes a driving means for switching the light flux limiting member disposed at the conjugate position, and the switching means is in a state where the first light flux limiting member is disposed at the conjugate position. Then, while the driving means is driven by a predetermined amount, an operation of changing the aperture diameter of the first light flux limiting member is performed, and the light flux limiting member disposed at the conjugate position by driving the driving means after the predetermined amount driving. Is switched from the first light flux restricting member to the second light flux restricting member .
(2) In the fundus imaging apparatus according to (1), the first light flux restricting member is a variable aperture, and the second light flux restricting member is a ring aperture.

  According to the present invention, it is possible to easily adjust the appearance of a captured image with a simple configuration. In addition, since a plurality of functions can be executed by a single driving means, the apparatus can be reduced in size and space.

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an optical system of the fundus imaging apparatus of the present embodiment.
Reference numeral 100 denotes a laser light emitting unit that emits laser light, and includes a plurality of laser light sources and mirrors. 1a is a semiconductor laser light source that emits laser light in the infrared region (wavelength 785 nm), 1b is a semiconductor laser light source that emits green (wavelength 532 nm) laser light, 1c is a semiconductor laser light source that emits blue (wavelength 490 nm) laser light, 1d Is a semiconductor laser light source that emits red (wavelength 660 nm) laser light. A beam splitter 101 transmits laser light from the semiconductor laser light sources 1a and 1d and reflects laser light from the semiconductor laser light source 1b. Reference numeral 102 denotes a beam splitter, which has a characteristic of transmitting laser light from the semiconductor laser light sources 1a, 1b, and 1d and reflecting laser light from the semiconductor laser light source 1c. Reference numerals 103 and 104 denote reflection mirrors. A beam splitter 105 transmits the laser light from the semiconductor laser light source 1a and reflects the laser light from the semiconductor laser light source 1d.

Laser light emitted from the semiconductor laser light source 1 a passes through the beam splitters 105, 101, and 102 and is emitted from the laser light emitting unit 100. The laser light emitted from the semiconductor laser light source 1 b is reflected by the mirror 103 and the beam splitter 101, passes through the beam splitter 102, and is emitted from the laser light emitting unit 100. The semiconductor laser light source 1 c is reflected by the mirror 104 and the beam splitter 102 and emitted from the laser light emitting unit 100. The laser light emitted from the semiconductor laser light source 1 d is reflected by the beam splitter 105, passes through the beam splitters 101 and 102, and is emitted from the laser light emitting unit 100. The laser light emitted from the semiconductor laser light source 1a is used for normal fundus photography and fluorescence photography (ICG), and the laser light emitted from the semiconductor laser light source 1b is used for normal fundus photography and fluorescence photography ( ICG) is used for illumination light. Laser light emitted from the semiconductor laser light source 1b is used for normal fundus photography, and laser light emitted from the semiconductor laser light source 1c is used for normal fundus photography and fluorescence photography (FAG). The laser light emitted from the semiconductor laser light source 1d is used as a fixation lamp.
2 is a perforated mirror having an opening in the center, and 3 is a lens. Reference numerals 4 and 5 denote mirrors which are movable in the direction of the arrow shown in FIG. 1 and can perform focusing (diopter correction) by changing the optical path length. 6, 8 and 10 are concave mirrors. 7 is a polygon mirror serving as a deflecting means for deflecting and scanning the laser beam in the horizontal direction on the fundus of the eye to be examined, and 9 is a deflecting means for deflecting and scanning the laser beam in a direction perpendicular to the scanning direction by the polygon mirror 7. It is a galvanometer mirror as a means.

  The laser light emitted from the laser light emitting unit 100 passes through the opening of the perforated mirror 2, passes through the lens 3, is reflected by the mirror 4, the mirror 5, and the concave mirror 6, and travels toward the polygon mirror 7. The light beam reflected by the polygon mirror 7 is reflected by the concave mirror 8, the galvano mirror 9, and the concave mirror 10, and then condensed on the fundus of the eye to be examined, and the fundus is two-dimensionally (in the XY axis direction shown in the drawing). ) Scan. An irradiation optical system is formed by these optical members.

  Reference numeral 12 denotes a lens, 13 is a variable diaphragm capable of changing the size of the aperture diameter, and 14 is a ring aperture. The variable aperture 13 and the ring aperture 14 are switched on the optical axis L by the switching mechanism 200. Details of the switching mechanism 200 will be described later. The lens 12 places an observation point on the fundus of the eye to be examined and a variable aperture 13 (ring aperture 14) placed on the optical axis L at a conjugate position. Reference numeral 15 denotes a condenser lens, and 16 denotes a light receiving unit. Note that an APD (avalanche photodiode) is used for the light receiving unit 16 of the present embodiment.

  The reflected light of the laser beam scanned on the fundus of the eye to be examined follows the irradiation optical system in the reverse direction, is reflected by the perforated mirror 2, and is bent downward. The pupil position of the eye to be examined and the opening of the perforated mirror 2 are conjugated by the lens 3. The reflected light reflected by the perforated mirror 2 is focused on the opening of the variable aperture 13 via the lens 12. The reflected light focused at the opening is received by the light receiving element 16 through the lens 15. A photographing optical system is formed by these optical members.

FIG. 2 is a diagram showing a schematic configuration of the switching mechanism 200, and FIG. 3 is a schematic sectional view of the switching mechanism 200 shown in FIG. 2 when viewed from the side.
201 is a base. The base 201 is slidably attached with a slide table 202 having a light beam limiting member for limiting the passage of light beams such as a variable aperture and a ring aperture. The slide table 202 is provided with an opening, on which the light flux limiting members such as the variable diaphragm 13 and the ring aperture 14 are disposed (see FIG. 3). Reference numeral 203 denotes a shaft attached to the slide table 202. As illustrated, the shaft 203 is inserted into the base 201 so as to be movable in the axial direction. Further, a spring 203a is installed between the base 201 and the slide table 202 in a state where the shaft 203 is inserted, and the spring 203a moves the slide table 202 in the axial direction of the shaft 203 (downward on the paper surface). Is energized.

  A stop plate 201 a is provided on the base 201. One surface of the sliding table 202 (which is the bottom surface in the figure) abuts against the stop plate 201a, thereby restricting the movement of the sliding table 202 in the biasing direction. In the state where the slide table 202 is in contact with the stop plate 201a, the variable diaphragm 13 is positioned on the opening 201b provided in the base 201 as shown in FIG. It will be located on the optical axis L shown in FIG.

  Reference numeral 204 denotes a pulse motor. Reference numeral 205 denotes a feed screw shaft connected to the pulse motor 204. A moving member 206 is screwed to the feed screw shaft 205. When the feed screw shaft 205 is rotated by driving the pulse motor 204, the moving member 206 is moved in the axial direction on the feed screw shaft. Yes. Reference numeral 207 denotes a flat plate joined to the moving member 206, and an extrusion portion 207 a for pushing the slide base 202 in a direction opposite to the urging direction as the moving member 206 moves is provided at the tip thereof. . Reference numeral 208 denotes a photosensor used as means for detecting whether or not the pushing portion 207a is in contact with the slide table 202. When the pushing portion 207a is not in contact with the slide table 202, the photo sensor 208 is shielded by the flat plate 207, and no detection signal is output. When the pushing portion 207a comes into contact with the slide table 202, the flat plate 207 is detached from the photosensor 208, and a detection signal is output.

  The variable diaphragm 13 is provided with a knob 13a. By rotating the knob 13a, the overlapping state of a plurality of blades (not shown) provided in the variable diaphragm is changed, and the aperture diameter of the diaphragm is changed. be able to. As shown in FIG. 2, the distal end portion of the knob 13 a is rotatably held by holding portions 206 a and 206 b provided inside the moving member 206. As the moving member 206 moves in the axial direction, the knob 13a rotates around the optical axis L while being held by the holding portions 206a and 206b, and changes the opening diameter of the variable diaphragm 13. Further, when the pushing portion 207 comes into contact with the slide table 202, in other words, when a detection signal is issued from the photosensor 208, the opening diameter of the variable diaphragm 13 becomes maximum. Since the mechanism for changing the aperture diameter of the diaphragm by changing the overlapping state of the blades by turning the knob is a conventionally known mechanism, its description is omitted.

  FIG. 4 is a block diagram illustrating a control system of the fundus imaging apparatus according to the present embodiment. A control unit 20 controls the entire apparatus. In the control unit 20, the semiconductor laser light sources 1a to 1d, the polygon mirror 7, the galvano mirror 9, the light receiving unit 16, the driving means 21 for driving the mirrors 4 and 5, and various conditions for the ophthalmologic photographing apparatus are set. An image processing unit 23, a pulse motor 204, a photosensor 208, and the like for forming an image of the fundus of the eye to be examined based on signals received by the control unit 22 and the light receiving unit 16 are connected. Reference numeral 24 denotes a monitor on which the fundus image formed by the image processing unit 23 is displayed. Reference numeral 25 denotes a storage unit for storing various information.

  The control unit 22 includes a dial 22a for changing the aperture diameter of the variable aperture 13 and switching between the variable aperture 13 and the ring aperture 14, a selection switch 22b for selecting laser light, and a refractive power value of the eye to be examined. For example, a switch 22c. By turning the dial 22a, the aperture diameter of the variable diaphragm 13 is switched stepwise from small to large. Further, by turning the dial 22a further from the rotational position of the dial 22a where the aperture diameter of the variable aperture 13 is maximized, the light flux limiting member located on the optical axis L shown in FIG. 1 is transferred from the variable aperture 13 to the ring aperture 14. It is possible to switch.

The operation of the fundus imaging apparatus having the above configuration will be described.
The examiner measures the refractive power of the eye to be examined in advance with an eye refractive power measuring device or the like, and inputs the obtained refractive power value of the eye to be examined using the switch 22 c of the control unit 22. In addition, using the dial 22a and the selection switch 22b of the control unit 22, the size of the opening diameter and the laser beam used as illumination light are selected. Here, the variable diaphragm 13 is disposed on the optical axis L, and the aperture diameter is minimized. In addition, infrared laser light is emitted from the semiconductor laser light source 1a.
When the apparatus is turned on, the control unit 20 initializes and drives the pulse motor 204 and confirms the position at which the photosensor 208 can obtain a detection signal (the position where the push-out unit 207a contacts the slide table 206). Thereafter, with this position as a reference, the pulse motor 204 is driven and controlled so as to meet the conditions set by the dial 22a of the control unit 22.

  The control unit 20 stores the input refractive power data in the storage unit 25 and drives the mirrors 4 and 5 using the driving unit 21 to perform diopter correction. With the diopter corrected, the examiner drives the apparatus using a joystick (not shown) so that the fundus of the eye to be examined is irradiated with laser light so that a desired image is displayed on the monitor 24. , Align.

  The controller 20 emits a predetermined laser beam from the semiconductor laser light source selected by the selection switch 22b. In addition, the control unit 20 intermittently emits red laser light from the semiconductor laser light source 1d to be used as a fixation lamp. Laser light emitted from the laser light emitting unit 100 passes through the opening of the perforated mirror 2, passes through the lens 3, is reflected by the mirrors 4, 5, and the concave mirror 6, and travels toward the polygon mirror 7. The polygon mirror 7 rotates at a constant speed, and the laser beam is reflected by the polygon mirror 7 and scanned in the horizontal direction.

  The laser beam scanned by the polygon mirror 7 is reflected by the concave mirror 8 and then further scanned in the vertical direction (from top to bottom) by driving the galvanometer mirror 9. The laser beam reflected by the galvanometer mirror 9 is reflected by the concave mirror 10, and is condensed on the fundus of the eye to be examined and also scans the fundus two-dimensionally.

The reflected light of the laser beam condensed on the fundus is traced backward from the concave mirror 10 to the perforated mirror 2 and is bent downward by the perforated mirror 2. The reflected light beam bent downward by the perforated mirror 2 is condensed on the opening of the variable aperture 13 via the lens 12. The reflected light collected at the opening of the variable aperture 13 is received by the light receiving unit 16 via the lens 15. The image processing unit 23 forms an image based on the light reception signal obtained by the light receiving unit 16 and the driving positions of the polygon mirror 7 and the galvano mirror 9 and displays the fundus image of the eye to be examined on the monitor 24.
Under the conditions described above, since the aperture diameter of the variable stop 13 is minimized, the resolution of the fundus image obtained is high, but the amount of light obtained is small and the whole becomes dark. For this reason, when it is desired to obtain a bright photographed image even if the resolution is slightly low, the dial 22a is used to widen the opening diameter of the opening of the variable aperture 13 so as to secure the light quantity.

  When the dial 22a is turned so as to maximize the opening diameter of the variable diaphragm 13, the control unit 20 drives the pulse motor 204 shown in FIG. When the pulse motor 204 is driven, the feed screw shaft 205 is rotated, and the moving member 206 is moved in the axial direction (upward in the drawing) as shown in FIG. The knob 13a is rotated according to the movement of the moving member 206, and the opening diameter of the variable diaphragm 13 is increased according to the rotation of the knob 13a. The control unit 20 drives and controls the pulse motor 204 until the opening diameter (here, the maximum diameter) set by the dial 22a is obtained. By such drive control, the aperture diameter of the variable aperture 13 is changed to secure the light amount, and a bright fundus image is obtained.

  In addition, when ICG fluorescence imaging is performed by irradiating the fundus of the eye to be examined with infrared laser light from the semiconductor laser light source 1a, the fluorescence of the fundus may be too bright and the surroundings may be difficult to see. In such a case, the ring aperture 14 is arranged on the optical axis L using the dial 22a, and the passage of the main reflected light from the observation point is suppressed by the ring aperture 14, thereby making it easy to see the entire fundus image. Can do.

  When switching to the ring aperture 14 is instructed by operating the dial 22a, the control unit 20 drives the pulse motor 204 from the current state until the ring aperture 14 is positioned on the optical axis L. When the moving member 206 further moves in the axial direction (upward in the drawing) from the state in which the pushing portion 207a comes into contact with the slide table 202 by the movement of the moving member 206 (the state in which the opening diameter of the variable aperture is maximum), the pushing portion 207a Will push the slide table 202. The slide table 202 is moved in the axial direction along the shaft 203 by being pushed by the pushing portion 207a. As shown in FIG. 6, the light flux limiting member arranged on the optical axis L is moved from the variable aperture 13 to the ring aperture. Switch to 14. At this time, the spring 203a is compressed.

  In addition, switching from the ring aperture 14 to the variable aperture 13 is performed by rotating the pulse motor 204 in the reverse direction. Due to the reverse rotation of the pulse motor 204, the feed screw shaft 205 also rotates in the reverse direction, and the moving member 206 moves in the direction opposite to the aforementioned direction (the direction away from the slide table 202). At this time, the sliding member 202 moves until the knob 13a abuts against the stop plate 201a without rotating the knob 13a by the urging force of the compressed spring 203a. By such an operation, switching from the ring aperture 14 to the variable aperture 13 is performed. Further, when the pulse motor 204 further rotates in the reverse direction, only the moving member 206 moves in the axial direction while the position of the slide table 202 is maintained, and accordingly, the knob 13a is rotated and the opening diameter is reduced.

  With such a mechanism, the appearance of the captured image can be easily adjusted. In addition, since the two functions of changing the opening diameter of the variable aperture 13 and the function of switching between the variable aperture 13 and the ring aperture 14 can be performed by a single driving means, the apparatus can be reduced in size. And space saving.

  In the above embodiment, the size of the opening diameter is changed stepwise. However, the present invention is not limited to this, and it goes without saying that the opening diameter can be changed continuously and changed to an arbitrary size. Absent. Also, instead of the ring aperture, a filter provided with means for restricting the passage of a light beam such as a black spot in the center is used, or in addition to a variable aperture and a ring aperture, other light beam restriction such as a polarizing filter having a predetermined optical characteristic is used. A member can also be prepared.

It is the schematic which showed the optical system of the fundus imaging apparatus of this embodiment. It is the figure which showed schematic structure of the switching mechanism of a variable aperture and a ring aperture. It is the schematic sectional drawing which showed the state which looked at the switching mechanism shown in FIG. 2 from the side. It is the block diagram which showed the control system of the fundus imaging apparatus of this embodiment. It is the schematic which showed the state which changed the opening diameter of the variable aperture_diaphragm | restriction in the switching mechanism. It is the schematic which showed the state switched to the ring aperture in the switching mechanism.

Explanation of symbols

2 Hole Mirror 3 Lens 7 Polygon Mirror 9 Galvano Mirror 12 Lens 13 Variable Aperture 14 Ring Aperture 15 Condensing Lens 16 Light Receiving Element 100 Laser Light Emitting Part 200 Switching Mechanism

Claims (2)

In a fundus photographing apparatus for photographing a fundus of a subject eye and displaying the fundus on a monitor, an optical member for condensing a laser beam on an observation surface of the fundus and a scanning unit for two-dimensionally scanning the laser beam with respect to the fundus An imaging optical system that obtains a captured image by receiving reflected light of the laser beam that is reflected at the fundus and shares at least a part of the irradiation optical system, and an imaging optical system within the imaging optical system. A first light flux limiting member that is detachably disposed at a position that is conjugate with the condensing point of the observation surface, and whose aperture diameter is variable in order to adjust the amount of reflected light received by the imaging optical system; In order to switch and arrange at least two kinds of light flux limiting members with a second light flux limiting member for restricting passage of main reflected light among the reflected light, and each of the at least two kinds of light flux limiting members at the conjugate position. Switching means and Have, the said changeover switching means comprises a driving means for switching the light beam restriction member placed in the conjugate position, said switching means said driven in a state in which the first light beam limiting member to the conjugate position is disposed While the means is driven by a predetermined amount, an operation of changing the opening diameter of the first light flux restricting member is performed, and the light flux restricting member disposed at the conjugate position is driven by the driving means after the predetermined amount is driven. A fundus photographing apparatus, wherein the first light flux restricting member is switched to the second light flux restricting member . The fundus imaging apparatus according to claim 1, wherein the first light flux limiting member is a variable aperture, and the second light flux limiting member is a ring aperture .

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