JPH11299738A - Eyeground photographing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the visual line of the eye to be tested from fluctuation in switching an optical system by linking the focussing part of an eyeground photographing optical system to a moving means to move a visibility index and adjusting the focus of the eyeground photographing optical system corresponding to the varying visibility. SOLUTION: A moving means 59 is manually moved and constituted of an operation knob 59a as the operation part and a converting mechanism 59b linked to the operation knob 59a to convert rotating motion of the operation knob 59a into linear motion. A relay lens 62, a visibility index 63, and a visible light emitting diode 64 are mounted on one output part of the converting mechanism 59b and linked to rotation of the operation knob 59b to move along the optical axis 27d. On the other hand, a focus lens 7 and a movable part 45 are mounted on the other output part of the converting mechanism 59b and linked to rotation of the operation knob 59a to move along the photographing optical axis 4 and the optical axis 46 respectively. That is, this eyeground photographing device is constituted so that the visibility index 63 and the focus lens 7 as the focussing part of an eyeground photographing optical system Sd are linked to move.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus photographing apparatus, and more particularly to a fundus photographing apparatus capable of adjusting the focus of a fundus photographing optical system in accordance with the diopter of an eye to be examined.

[0002]

2. Description of the Related Art A fundus camera (fundus photographing apparatus) is one of the ophthalmologic apparatuses. This is an apparatus for photographing the fundus of the eye to be examined.

In order to photograph a predetermined position of the fundus oculi, the photographing is performed after the eye gaze of the eye to be examined is guided by a fixation target. On the other hand, since the fundus optics illuminates and photographs through the pupil, it is important to align the fundus photographing optical system with the pupil of the eye to be examined. With the conventional manual operation of the fundus power mela,
I was shooting according to the following procedure. First, the front end of the subject's eye facing the front is observed by the anterior eye observation optical system, and the optical axis is adjusted so that the pupil is captured in the center of the observation screen. Then, the working distance is adjusted by, for example, a split image. This allows
The optical system and the subject's eye are roughly aligned. Next, the optical system of the camera is switched to the fundus photographing optical system to project the fundus. Then, focus on the fundus using the split image. When the subject is in focus, the fixation target is in focus, so that the subject can clearly recognize the fixation target. Then, the photographing is performed after the detailed positioning is performed using the prepared index light.

As described above, in the manually operated fundus camera, complicated operations are required, and it takes a long time to photograph, so that the subject is forced to be nervous for a long time. In order to eliminate such a complicated operation and shorten the time required for photographing, a fundus force lens that automatically aligns the optical system with the eye to be examined has been proposed. The operation of this fundus camera is automatically performed as follows. First, X is determined by the observation screen of the anterior segment observation optical system.
The alignment in the Y direction is performed, and then the working distance is adjusted. Next, the optical system of the camera is switched to the fundus photographing optical system. Next, automatic focusing is performed on the fundus, and a fundus image is captured.

[0005] In this apparatus, two optical fixation targets are provided because the optical path that can be peeped by the subject is switched by switching the optical system. In other words, a system of the fixation lamp that the subject's eye sees before switching the optical system and a system of the fixation target that looks after the switching are provided, so that the line of sight of the subject's eye does not fluctuate even when the optical system switches. is there.

[0006]

However, since the diopter varies depending on the eye to be examined, the fixation target may not be clearly visible depending on the examinee. That is,
Originally, the fixation target is focused only when focusing on the fundus is performed.However, with the automatic fundus camera, it is necessary to show the fixation target to the subject before switching the optical system. The fixation target is shown without fundus focusing. There is no problem if the eye to be examined has a diopter that allows the fixation target to be clearly recognized, but if not, especially if the diopter of the subject's eye greatly deviates from the standard diopter. Cannot see the fixation target clearly and cannot fixate correctly. Then, alignment cannot be performed, and fixation becomes inconsistent at the time of switching the optical system, and the line of sight fluctuates, which hinders the operation of the fundus camera thereafter.

SUMMARY OF THE INVENTION In view of the above problems, the present invention can adjust the focus of the fundus photographing optical system according to the diopter of the eye before switching the optical system, and prevents fluctuation of the line of sight of the eye when the optical system is switched. It is an object of the present invention to provide a fundus photographing device capable of performing the above.

[0008]

In order to solve the above-mentioned problems, a fundus photographing apparatus according to the present invention includes a fundus photographing optical system for photographing a fundus of a subject's eye, a diopter index, and a diopter index. Moving means for moving the diopter in a direction in which the diopter changes, and a focus adjustment unit that adjusts the focus of the fundus imaging optical system is interlocked with the moving means, and adjusts to the diopter of the diopter index that changes with the movement. Thus, the focus of the fundus photographing optical system is adjusted (claim 1). In this fundus imaging device,
Detecting means for detecting a variable that changes in accordance with the position of the diopter index, wherein the focus adjustment unit adjusts the diopter of the diopter index based on the output of the detecting means, (Claim 2). With such a configuration, the position of the diopter index can be continuously changed. Then, the diopter index is stopped at a position where the subject can most clearly recognize, and the focus of the fundus imaging optical system can be adjusted based on the position of the diopter index. The sway of the line of sight can be prevented.

The fundus photographing apparatus may further include an anterior segment observation optical system for observing an anterior segment of the eye to be examined, and the diopter index may be incorporated in the anterior segment observation optical system. (Claim 3). With this configuration,
Since a clear diopter index can be shown as a fixation target when observing the anterior segment, the anterior segment can be observed in a state where the line of sight of the subject's eye is stabilized. Further, when the optical system is switched from the anterior ocular segment observation optical system to the fundus imaging optical system, a clear fixation target on the fundus imaging optical system side can be immediately confirmed, so that the line of sight of the eye to be inspected does not fluctuate.

Further, in the fundus photographing apparatus, it is preferable that the moving means includes an operation unit, and the diopter index moves in response to an operation of the operation unit.

The moving means may be a manual device (claim 5) or may be provided with a power unit for moving the diopter index (claim 6).

Further, an alignment index light is projected on the eye to be examined, an eyeball reflection image of the alignment index light is received by an anterior ocular segment observation optical system, and the fundus imaging optical system is followed while following the eyeball reflection image. (Claim 7).
With this configuration, the line of sight is stabilized during alignment, so that accurate alignment can be performed.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

First, an apparatus configuration of a fundus photographing apparatus 1 according to an embodiment of the present invention will be described with reference to FIGS. 1, 2 and 3. FIG. 1 is a block diagram illustrating a schematic configuration of the fundus imaging apparatus 1, and FIG. 2 is a block diagram illustrating a configuration of an anterior ocular segment observation optical system Sa provided in the fundus imaging apparatus 1 in detail. FIG. 7 is a diagram showing a relationship among a diopter index 63, a moving unit 59, a focus lens 7, and the like.

As shown in FIG. 1, the fundus photographing apparatus 1 mainly includes a mirror 3 on which various optical systems are disposed, and a driving mechanism (an XY axis driving mechanism 50, a Z axis A drive mechanism 52) and a control circuit 91 for processing signals from the optical system and controlling the drive mechanism.

On the mirror body 3, mainly the anterior ocular segment observation optical system S
a, a working distance index projection optical system Sb, a working distance detection optical system Sc, and a fundus photographing optical system Sd.

The anterior ocular segment observation optical system Sa is an optical system of a portion surrounded by a dashed line indicated by reference numeral Sa in FIG. 1, and the configuration thereof is shown in detail in FIG. The anterior ocular segment observation optical system Sa projects the alignment index light on the ocular sphere F of the eye E, receives the reflected light of the index light from the ocular sphere F, and generates an anterior eye image of the eye E. An optical system for receiving an image. In addition, an optical system 80 for detecting the diopter of the eye E to be inspected is incorporated in the anterior ocular segment observation optical system Sa.

The anterior ocular segment observation optical system Sa includes an infrared light emitting diode 21 for emitting alignment index light for projecting and receiving alignment index light and receiving an anterior ocular segment image.
a, a condenser lens 23, a mirror 25 and a concave lens 26, a half mirror 24, an anterior eye observation lens 28, a television camera 30, and an anterior eye illumination light source 21b. The concave lens 26 is for performing a correction for canceling out the strong power of the objective lens 5, and a lens having a strong canceling out power is used. The infrared light, which is the alignment index light emitted from the infrared light emitting diode 21a, passes along the converging lens 23 and the half mirror 2 along the alignment index optical axis 27a.
4, the light is reflected by the mirror 25, and the optical path is bent on the photographing optical axis 4. Further, the alignment index light passes through the concave lens 26 and the objective lens 5 of the fundus imaging optical system Sd, and is projected as parallel light toward the eye spherical surface F of the eye E to be inspected. Then, the reflected light of the alignment index light from the eye sphere F passes through the objective lens 5 and the concave lens 26,
Reflected by the mirror 25, the alignment index optical axis 27
The optical path can be bent over a. Further, the reflected light is reflected by the half mirror 24, and the optical path is bent on the anterior ocular segment observation optical axis 27b. The reflected light passing through the anterior ocular segment observation lens 28 is reflected by the CCD light receiving surface 2
9 and is imaged. Also, the anterior segment image of the eye E to be examined is
The light is input to the television camera 30 along the same route as the reflected light of the alignment index light. The light source 21b for anterior segment illumination is
It is provided to illuminate the eye E with infrared light so that the anterior segment image is formed more clearly. The image signal output from the television camera 30 is input to the control circuit 91.

The concave lens 26 and the mirror 25 are retracted from the photographing optical axis 4 by the optical path switching mechanism 54 when photographing the fundus with the fundus photographing optical system Sd.

As described above, the anterior ocular segment observation optical system S
An optical system 80 for detecting the diopter of the eye E is incorporated in a. As shown in FIG.
0 is the optical axis 27 by the visible light reflecting infrared transmitting mirror 61.
A relay lens 62, a diopter index 63, and a visible light emitting diode 64 are provided on the optical axis 27d bent from the position a. The pattern represented by the diopter index 63 is applied to the visible light emitting diode 64 from the back. The relay lens 62, the diopter index 63, and the visible light emitting diode 64 are configured to be integrally movable along the optical axis 27d, and the moving means 59 moves these.

Referring again to FIG. 1, the working distance target projection optical system Sb is provided with a working distance detecting light emitting diode disposed along a working distance detection target optical axis 35a at 45 degrees to the photographing optical axis 4. (Infrared LED) 31, condenser lens 3
2. Working distance detection index slit 33 and projection lens 3.
4 Light emitting diode 31 for detecting working distance
Light travels along the optical axis 35a of the working distance detection index, the condenser lens 32 and the slit 3 for the working distance detection index.
3. By sequentially passing through the projection lens 34, it is incident on the eye sphere F as working distance detection index light.

The working distance detecting optical system Sc includes an imaging lens 36 for receiving the working distance detecting index light reflected by the eye sphere F, and a working distance detecting light receiving element (PSD).
37. The imaging lens 36 and the working distance detecting light receiving element 37 are provided with a working distance detecting optical axis 35b symmetrical with respect to the photographing optical axis 4 with the working distance detecting index optical axis 35a.
It is arranged along. Then, the working distance detecting light receiving element 37 outputs a light receiving signal accompanying the reception of the working distance detecting index light to the control circuit 91.

The fundus photographing optical system Sd is an optical system in a portion surrounded by a dashed line indicated by reference numeral Sd in FIG. The fundus imaging optical system Sd includes an optical system Sd1 for illuminating the fundus of the eye E, an optical system Sd2 for photographing the fundus based on the illumination light of the optical system Sd1, and a focus of the optical system Sd2. It is composed of an optical system Sd3 for adjusting to the fundus of E.

The optical system Sd1 includes a strobe discharge tube 11, condensing lenses 12, 13, a circular slit 14, a mirror 15,
Condensing lenses 18 and 20 and a perforated mirror 6 are provided. The visible light emitted from the strobe discharge tube 11 is focused by the condenser lenses 12 and 13 at the position of the circular slit 14, passes through the circular slit 14, is reflected by the mirror 15, and folds the optical path on the illumination optical axis 16. Bendable. Further, this visible light travels on the illumination optical axis 16, and the condenser lens 18,
The light is focused near the perforated mirror 6 through the half mirror 19 and the condenser lens 20 of the optical system Sd3, and an image of a circular slit is formed on the perforated mirror 6. Further, this visible light is reflected by a perforated mirror 6, the optical path is bent on the photographing optical axis 4, passes through the objective lens 5, converges from the apex position of the eye E to the vicinity of the pupil, and irradiates the retina surface of the fundus. It is supposed to.

The optical system Sd2 includes an objective lens 5, a focus lens 7, a relay lens 8, and a television camera (color television camera for fundus imaging). These members are disposed on the photographing optical axis 4. The fundus image passes through the objective lens 5, the perforated mirror 6 of the optical system Sd 1, the focus lens 7 and the relay lens 8, and
An image is formed on the CCD light receiving surface 9 and photographed. The image signal output from the television camera 10 is input to the control circuit 91. The focus lens 7 functions as a focus adjustment unit that adjusts the focus of the fundus imaging optical system Sd.

The optical system Sd 3 includes a halogen lamp 38, a condenser lens 39, an automatic focus index slit 40, a projection lens 41, a split prism 42, a fixation target 43, a condenser lens 44 and a half mirror 19. Among them, a halogen lamp 38, a condenser lens 39, a slit 40 for an automatic focus index, a projection lens 41, a split prism 4
2 and the fixation target 43 integrally form a movable part 45. The fixation target 43 is provided at substantially the same position as the split prism 42. This position is equivalent to the position of the CCD light receiving surface 9, which is the image forming position of the television camera 10. The fixation target 43 displays the line of sight of the eye E to be inspected fixed by the diopter index 63 incorporated in the anterior ocular segment observation optical system Sa to the mirror 25.
The concave lens 26 and the concave lens 26 are provided so as to be fixed and maintained at the same angle even after retreating from the photographing optical axis 4.

An XY-axis drive mechanism 50 and a Z-axis drive mechanism 52 are interposed between the mount of the fundus photographing apparatus 1 and the mirror 3, and the position of the mirror 3 with respect to the mount is changed by these drive mechanisms. . The Z-axis drive mechanism 52 is a drive mechanism for moving the mirror body 3 in the Z direction. Here, the Z direction is a direction (left-right direction in FIG. 1) approaching / separating from the eye E to be examined. Note that the direction of the photographing optical axis 4 coincides with the Z direction. The XY-axis drive mechanism 50 moves the mirror body 3 to X
This is a driving mechanism for moving in the Y direction. Here, the X direction refers to a direction orthogonal to the Z axis in a horizontal plane (a direction perpendicular to the plane of FIG. 1). Also, the Y direction is
It refers to the vertical direction (vertical direction in FIG. 1).

The control circuit 91 receives signals from the television camera 10, the television camera 30, and the light receiving element 37 for detecting the working distance, processes these signals in accordance with a predetermined procedure, and performs XY-axis driving mechanism 50, Z-axis driving This is a circuit for sending a control signal to the mechanism 52, the optical path switching mechanism 54, the focusing drive mechanism 56, and the like.

Next, how the moving means 59, the diopter index 63, the focus lens 7 and the like are connected will be described with reference to FIG. The moving means 59 is a manual device, and includes an operation knob 59a as an operation unit and an operation knob 5
A conversion mechanism 5 such as a rack and pinion mechanism connected to the control knob 9a for converting the rotational movement of the operation knob 59a into a linear movement;
9b. The relay lens 62, the diopter index 63, and the visible light emitting diode 64
b, which is attached to one of the output sections and has an operation knob 5
It moves along the optical axis 27d in conjunction with the rotation of 9a. On the other hand, the focus lens 7 and the movable part 45 are
The operation knob 59
It moves along the photographing optical axis 4 and the optical axis 46 in conjunction with the rotation of a. That is, the diopter index 63 and the focus lens 7 serving as the focus adjustment unit of the fundus imaging optical system Sd are configured to move in conjunction with each other. Since the diopter of the diopter index 63 is determined by the position on the optical axis 27d, when the operation knob 59a is rotated to change the position of the diopter index 63, the diopter also changes. On the other hand, when the operation knob 59a is rotated, the positions of the focus lens 7 and the movable part 45 also change, so that the focus of the fundus imaging optical system Sd also changes. It is configured to follow the change of. That is, no matter what position the diopter index 63 is moved by rotating the operation knob 59a, the focus of the fundus imaging optical system Sd always matches the diopter of the diopter index 63. Although the diopter index 63 and the focus lens 7 move by the rotation of the operation knob 59a, the movement amounts of the diopter index 63 and the focus lens 7 may be the same or different. Further, the moving directions may be the same or opposite. The point is that the change in the focus of the fundus imaging optical system Sd can follow the change in the diopter of the diopter index 63.

Next, the operation and operation procedure of the fundus photographing apparatus 1 will be described. The operation and operation procedures are (1) diopter detection and preliminary focus adjustment, (2) alignment, (3) working distance adjustment, (4)
It can be divided into focusing and (5) fundus photography. Hereinafter, description will be given for each of these steps.

(1) Diopter Detection / Preliminary Focus Adjustment First, when the subject fixes his / her head on a jaw table (not shown) provided on the front surface of the fundus imaging apparatus 1, the operator of the fundus imaging apparatus 1 Operates the jaw base to adjust the monitor display 92 so that the anterior segment of the subject's eye E of the subject whose image has been received by the television camera 30 is displayed. In the state where this adjustment is made, the eye to be inspected is located near the optical axis 4 as shown in FIG. At this time, the subject can see the diopter index 63 incorporated in the optical system 80 through the objective lens 5.

Next, the examinee moves the diopter index 63 to a position where the diopter index 63 can be most clearly seen while rotating the operation knob 59a. That is, the operation knob 5
The diopter index 63 moves on the optical axis 27d by the rotation of 9a. Then, the optical path length from the eye E to the diopter index 63 changes, and the diopter of the diopter index 63 changes. The subject moves the diopter index 63 to a position most suitable for his or her diopter, that is, a position where the diopter can be seen most clearly.

The diopter is usually expressed in a unit called diopter. When the diopter is expressed in this unit, for a subject eye whose numerical value is a standard numerical value (standard value), the diopter index 63 is set when the diopter index 63 is substantially at the center position of the movable range. You can see it most clearly. For a subject's eye whose numerical value deviates to some extent from the standard value to the plus side, the diopter index 63 can be seen clearly by moving the eye to a distant position. Conversely, for a subject's eye whose numerical value deviates to some extent from the standard value to the negative side, the diopter index can be seen clearly by moving the eye closer to the subject.
In this way, the diopter of the eye E determines to which position the diopter index 63 can be most clearly seen when the diopter index 63 is moved. Whatever the diopter of the subject's eye E is, the diopter index 63 is located at the position where the eye can be seen most clearly.
The fixation can be stabilized by moving.

On the other hand, as described above, the operation knob 59a
Is rotated by moving the focus lens 7 and the movable part 45 on the photographing optical axis 4 and the optical axis 46, and the fundus photographing optical system Sd
Is made to follow the diopter of the diopter index 63. Therefore, the preliminary focus adjustment is performed at the same time when the diopter index 63 is aligned.

When the positioning of the diopter index 63 is completed, the subject or the operator operates the start switch (not shown) to give a start signal to the control circuit 91. Or later,
The fundus imaging apparatus 1 automatically performs the processes from alignment to fundus imaging.

As will be described later, the optical system for receiving the eye E is changed from the anterior ocular segment observation optical system Sa to the fundus imaging optical system Sd.
After that, the final focus adjustment (focusing) is performed.

(2) Alignment Upon receiving the start signal, the control circuit 91 next sets the infrared light emitting diode 21 a and the working distance detecting light emitting diode 3
1 is turned on. Then, the Z-axis driving mechanism is used until the eyeball reflection image (Purkinje image) due to the reflected light from the eyeball F of the alignment index light is clearly shown in the anterior eye image shown on the imaging screen of the television camera 30. By driving 52, the lens body 3 is advanced toward the subject's eye E. When the Purkinje image is clearly recognized on the imaging screen of the television camera 30, the mirror 3 is moved to X so that the Purkinje image falls within a predetermined range set at a substantially central portion on the imaging screen of the television camera 30.
Drive in the Y direction. When the Purkinje image falls within the predetermined range, the alignment in the XY directions is completed. As described above, the subject looks at the diopter index 63 of diopter that matches the diopter of the eye E, so that fixation is stabilized, and thus alignment is performed accurately.

(3) Working Distance Adjustment Next, the Purkinje image is maintained so that the state where the Purkinje image remains within the predetermined range on the photographing screen, that is, the aligned state is maintained. The working distance is adjusted while controlling the XY-axis driving mechanism 50 while following. The working distance adjustment is performed by advancing the mirror 3 toward the eye E until the working distance detecting light receiving element 37 receives the working distance detection indicator light (ocular reflected light).

That is, when the alignment is completed, the fundus photographing optical system Sd is located at a position farther from the eye E than the working distance. (Vertex) Not incident on the ER. When the mirror 3 reaches a certain distance with respect to the eye E due to the advance of the mirror 3, the working distance index projection optical system S
The index light by b is incident on the vertex of the eye to be examined on the eye spherical surface F, and the reflected light is received by the light receiving element 37 for detecting the working distance. When the control circuit 91 detects that the working-distance detecting light receiving element 37 has received the working-distance detection index light (eyeball reflected light), the XY-axis driving mechanism 50 and the Z-axis driving mechanism 52
Is stopped. Thus, the working distance adjustment is completed. Further, the maintenance of the alignment state in the XY directions, which has been performed while following the Purkinje image, is terminated by temporarily stopping the XY axis driving mechanism 50.

(4) Focusing When the working distance adjustment is completed as described above, a completion signal is output from the control circuit 91 to the optical path switching mechanism 54, and in response, the optical path switching mechanism 54 causes the mirror 25 and the concave lens 26.
Are retracted from the photographing optical axis 4. In this way, the optical system that receives the eye E is switched from the anterior ocular segment observation optical system Sa to the fundus imaging optical system Sd. However, since the preliminary focus adjustment of the fundus imaging optical system Sd has already been performed,
The subject can watch the clear image of the fixation target 43 immediately after the switching. Therefore, the line of sight of the eye E does not fluctuate.

Then, focusing is performed by the following known method. That is, the control circuit 91 controls the halogen lamp 38
Is turned on, and the movable portion 45 of the optical system Sd3 and the optical system Sd2 until the focus is detected by a detection optical path (not shown).
Is moved in conjunction with the focus lens 7 in the Z direction. The movement of the movable section 45 and the focus lens 7 is performed by sending a drive signal from the control circuit 91 to the focusing drive mechanism 56.

As described above, since the preliminary focus adjustment of the fundus photographing optical system Sd has already been performed before the switching of the optical system, the moving amount of the movable unit 45 and the focus lens 7 at this stage is not so large. Absent. Therefore, the time from when the optical system is switched to when the focusing is completed is greatly reduced as compared with the conventional fundus imaging apparatus.

Thus, the final focus adjustment (focusing)
Is completed, the halogen lamp 38 is turned off.

(5) Fundus Photographing When the focusing is completed as described above, the control circuit 91 controls the strobe light emitting circuit 57 to cause the strobe discharge tube 11 to emit light. To shoot. After photographing the fundus, the mirror 3 returns to the initial standby position and enters the standby state. The operation and operation procedure of the fundus imaging apparatus 1 are as described above.

Next, another configuration example of the moving means will be described with reference to FIGS.

The moving means 95 shown in FIG. 4 differs from the moving means 59 shown in FIG. 3 in that it has a motor 95d as a power unit. As an operation unit, an operation switch 95a for controlling normal rotation, stop, and reverse rotation of the motor 95d is provided. 9
5c is a control circuit for controlling the motor 95d. That is, depending on the position of the mover of the operation switch 95a,
The motor 95d rotates forward, stops, or reversely rotates. The motor 95d has a conversion mechanism 9 such as a rack and pinion mechanism for converting the rotational movement of the motor 95d into a linear movement.
5b. Relay lens 62, diopter index 6
3 and the visible light emitting diode 64 include a conversion mechanism 95b.
And is moved along the optical axis 27d in conjunction with the rotation of the motor 95d. On the other hand, the focus lens 7 and the movable part 45 are attached to the other output part of the conversion mechanism 95b, and move along the photographing optical axis 4 and the optical axis 46 in conjunction with the rotation of the motor 95d. Also in this case, the focus of the fundus imaging optical system Sd is configured to always match the diopter of the diopter index 63 irrespective of the position of the diopter index 63, as in the apparatus of FIG. When the subject operates the operation switch 95a, the diopter index 6 is set to the position where the subject can see the sharpest.
When 3 is moved, preliminary focusing of the fundus imaging optical system Sd is performed at the same time.

The moving means 96 shown in FIG. 5 is provided with a motor 96d as a power unit and a reciprocating mechanism 96b such as a slider / crank mechanism for converting the rotational movement of the motor 96d into a reciprocating linear movement. The motor 96d is connected to the reciprocating mechanism 96b. An operation switch 96a for controlling start / stop of the motor 96d is provided as an operation unit.
It has. A control circuit 96c controls the motor 96d. That is, the motor 96d rotates or stops depending on the position of the mover of the operation switch 96a. The relay lens 62, the diopter index 63, and the visible light emitting diode 64 are attached to one output of the reciprocating mechanism 96b, and reciprocate on the optical axis 27d in conjunction with the rotation of the motor 96d. On the other hand, the focus lens 7 and the movable section 45 are attached to the other output section of the reciprocating mechanism 96b, and reciprocate on the photographing optical axis 4 and the optical axis 46 in conjunction with the rotation of the motor 96d. Also in this case, the focus of the fundus imaging optical system Sd is configured to always match the diopter of the diopter index 63 irrespective of the position of the diopter index 63, as in the apparatus of FIG. I have. By operating the operation switch 96a, the subject can reciprocate the diopter index 63 and stop the diopter index 63 at a position where the user can see the sharpest. At the same time, preliminary focusing of the fundus imaging optical system Sd is performed.

Next, another embodiment of the fundus photographing apparatus according to the present invention will be described with reference to FIGS. FIG. 6 is a block diagram showing a schematic configuration of the fundus imaging apparatus 1 ′. FIG. 7 shows a specific configuration of the moving unit 97 that moves the diopter index 63 and the detecting unit 58 that detects the position of the diopter index 63. FIG.

As in the fundus photographing apparatus 1 of FIG. 1, the fundus photographing apparatus 1 'of FIG. 6 mainly has a mirror body 3 on which various optical systems are disposed, and a driving mechanism for driving the mirror body 3. (XY
An axis driving mechanism 50, a Z-axis driving mechanism 52) and a control circuit 91 for processing signals from the optical system and controlling the driving mechanism. On the mirror body 3, an anterior ocular segment observation optical system Sa ', a working distance index projection optical system Sb, a working distance detection optical system Sc, and a fundus imaging optical system Sd are mainly disposed. The configuration of each optical system is substantially the same as that of the fundus imaging apparatus 1 of FIG. However, the fundus photographing optical system S
The focus lens 7 serving as a focus adjustment unit for the d.
3 differs from the fundus imaging apparatus 1 in FIG. 1 in that it is indirectly linked to a moving means for moving the position 3 via a detecting means 58 for detecting the position of the diopter index. Hereinafter, this difference will be mainly described.

FIG. 7 shows a relay lens 62, a diopter index 63 incorporated in the anterior ocular segment observation optical system Sa ', a moving means 97 for moving these, and a detecting means 58 for detecting its position.
This is for explaining the relationship. Relay lens 6
2. Diopter index 63 and visible light emitting diode 64
They are configured to be integrally movable along the optical axis 27d, are moved by the moving means 97, and their positions are detected by the detecting means 58. Moving means 97
For example, various configurations as shown in FIGS. 3 to 5 can be adopted. The detecting means 58 includes a resistor 58a through which a direct current flows, and a slider 58b sliding on the resistor 58a. The slider 58b includes a relay lens 62, a diopter index 63, and a visible light emitting diode 64.
And move together. The position of the diopter index 63 detected by the detecting means 58 is determined as the voltage of the slider 58b by the control circuit 9.
Sent to 1. That is, in this case, the position of the diopter index 63 is a variable, and this detecting means 58 detects this variable.

While the subject operates the moving means 97,
When the diopter index 63 is moved to a position where the diopter index 63 can be seen most clearly, the position of the diopter index 63 is detected by the detecting unit 58. An output signal of the detecting means 58,
That is, the voltage of the slider 58b is sent to the control circuit 91, and the control circuit 91 can know the diopter of the diopter index from this signal. Then, in order to focus the fundus photographing optical system Sd in accordance with the diopter, a focusing drive mechanism 56 is used.
To output a drive signal. The focus drive mechanism 56 receives the drive signal and moves the focus lens 7 and the movable section 45 in conjunction with each other. The focus lens 7 moves along the optical axis 4, and the movable part 45 moves along the optical axis 46. The position to which the focus lens 7 and the movable part 45 are moved is determined by an output signal from the detection means 58. That is, since the diopter of the diopter index can be known from the magnitude of the output signal from the detecting means 58, the focus lens 7 and the movable part 45 are moved in accordance with the diopter and the diopter of the fundus imaging optical system Sd is changed. Preliminary focus adjustment is performed.

In this way, the diopter is detected, and at the same time, the preliminary focus adjustment is performed, that is, the diopter detection and the preliminary focus adjustment are performed in parallel in time. After the preliminary focus adjustment is performed, alignment, working distance adjustment, focusing (final focus adjustment), and fundus imaging are performed in the same operation procedure as the fundus imaging apparatus 1 in FIG.

The apparatus configuration, operation, and operation procedure of the fundus photographing apparatus 1 'are as described above. In the above description, preliminary focus adjustment is performed simultaneously with diopter detection. After completion of the preliminary focus adjustment, alignment and working distance are performed. He explained that adjustments will be made.

However, after the diopter detection is completed, that is,
After moving the diopter index 63 to a position where the examinee can see the sharpest by the moving means 97, the operator or the examinee operates an activation switch (not shown), and the control circuit 91 activates the activation switch. After receiving the activation signal from the switch, the preliminary focus adjustment may be performed based on the detection signal of the detection means 58.

Further, the preliminary focus adjustment may be performed in parallel with the alignment and the working distance adjustment after detecting the diopter. That is, the operation of the preliminary focus adjustment may proceed simultaneously with the operation of the alignment and the working distance adjustment. In short, it is only necessary that the preliminary focus adjustment be completed before the optical system is switched from the anterior ocular segment observation optical system Sa ′ to the fundus imaging optical system Sd.

Next, another configuration example of the detecting means will be described with reference to FIG. The moving means 99 is composed of an operation knob 99a and a conversion mechanism 99b, like the moving means 59 of FIG.
b is converted into a linear motion.
2. The diopter index 63 and the visible light emitting diode 64 move along the optical axis 27d. The detecting means 98 detects the rotation angle of the operation knob 99a. Detecting means 9
Reference numeral 8 denotes a pulse generator that outputs a pulse according to the rotation of the operation knob 99a, and an integrator that accumulates the pulse generated by the pulse generator. The integrated value is a variable that changes in accordance with the position of the diopter index 63, and the detecting unit 98 sends the integrated value to the control circuit 91. The control circuit 91 can know the diopter of the diopter index 63 from the integrated value. Then, in order to focus the fundus photographing optical system Sd in accordance with the diopter, the focus driving mechanism 5 is used.
6 to output a drive signal. As described above, instead of directly detecting the position of the diopter index 63, the diopter index 63 is changed using various variables that change in accordance with the position of the diopter index 63.
May be detected.

In the fundus photographing apparatuses 1 and 1 'shown in FIGS.
Although the diopter index 63 is incorporated in the anterior eye observation optical system Sa, Sa ', the diopter index 63 does not necessarily need to be incorporated in the anterior eye observation optical system.

In the fundus photographing apparatuses 1 and 1 ', a fixation target 43 is provided on the optical system Sd3 whose optical axis is branched from the optical system Sd2 in front of the focus lens 7 (to the left in FIGS. 1 and 6). Is provided. However, some fundus imaging apparatuses do not include a focusing optical system such as the optical system Sd3. In such a fundus photographing apparatus, a fixation target is provided at a position behind (to the right in FIGS. 1 and 6) the focus lens 7. In this case as well, the fixation target is configured to be visible through the focus lens 7, but the position of the fixation target is equivalent to the imaging position of the camera of the fundus imaging optical system. Therefore, the subject can clearly see the fixation target immediately after switching the optical system by adjusting the movement of the focus lens 7 by the preliminary focus adjustment.

Further, a general fundus photographing apparatus is used for the right eye,
A separate fixation target is provided for the left eye, and further for each visual axis direction to be guided. In the above description, only one diopter index 63 is shown in the optical system 80, and only one fixation target 43 is shown in the optical system Sd3, in order to avoid complicated description. But these diopter indices,
The fixation target may be provided separately for the right eye and for the left eye, or separately for each visual axis direction to be guided.

[0060]

As described above, according to the fundus photographing apparatus of the present invention, the following effects can be obtained.

(1) Preliminary focus adjustment can be performed before using the fundus imaging optical system, and the final focusing can be quickly and accurately performed after the use of the fundus imaging optical system. Moreover, since the position of the diopter index can be continuously changed, accurate preliminary focus adjustment can be performed.

(2) In a fundus photographing apparatus configured so that the diopter index is incorporated into the anterior segment observation optical system, a clear diopter index (fixation target) can be shown when observing the anterior segment. The anterior eye part can be observed in a state where the line of sight of the subject's eye is stabilized. Further, when the optical system is switched from the anterior ocular segment observation optical system to the fundus photographing optical system, a clear fixation target can be immediately confirmed, so that the line of sight of the subject's eye does not fluctuate.

(3) In a fundus photographing apparatus that automatically performs alignment of a fundus photographing optical system while following a reflected spherical image of the eye, a line of sight of the eye to be examined can be stabilized at the time of alignment, so that accurate alignment is possible. .

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a fundus imaging apparatus.

FIG. 2 is a block diagram showing in detail a configuration of an anterior ocular segment observation optical system provided in the fundus imaging apparatus.

FIG. 3 is a diagram illustrating a relationship between a diopter index, a moving unit, a focus lens, and the like.

FIG. 4 is a diagram showing another configuration example of the moving means.

FIG. 5 is a diagram showing another configuration example of the moving means.

FIG. 6 is a block diagram illustrating a schematic configuration of a fundus imaging apparatus.

FIG. 7 is a configuration diagram showing a specific configuration of a moving unit that moves the diopter index and a detecting unit that detects the position of the diopter index.

FIG. 8 is a diagram showing another configuration example of the detection means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1 'Fundus imaging device 3 Mirror 4 Imaging optical axis 5 Objective lens 6 Mirror 7 Focus lens 8 Relay lens 9 CCD light receiving surface 10 Television camera 11 Strobe discharge tube 12, 13 Condenser lens 14 Circular slit 15 Mirror 16 Illumination light Axis 18 Condensing lens 19 Half mirror 20 Condensing lens 21a Infrared light emitting diode 21b Light source for anterior segment illumination 23 Condensing lens 24 Half mirror 25 Mirror 26 Concave lens 27a Alignment index optical axis 27b Anterior segment observation optical axis 27d Optical axis 28 Anterior eye observation lens 29 CCD light receiving surface 30 TV camera 31 Working distance detecting light emitting diode 32 Condensing lens 33 Working distance detecting index slit 34 Projection lens 35a Working distance detecting index optical axis 35b Working distance detecting optical axis 36 Conclusion Image lens 37 Receiver for working distance detection Optical element 38 Halogen lamp 39 Condensing lens 40 Slit for automatic focus index 41 Projection lens 42 Split prism 43 Fixation target 44 Condensing lens 45 Movable part 46 Optical axis 50 XY axis driving mechanism 52 Z axis driving mechanism 54 Optical path switching mechanism 56 Focusing drive mechanism 57 Strobe light emitting circuit 58 Detecting means 58a Resistance 58b Slider 59 Moving means 59a Operation knob 59b Conversion mechanism 61 Visible light reflective infrared transmitting mirror 62 Relay lens 63 Diopter index 64 Visible light emitting diode 80 Optical system 91 Control circuit 92 Monitor display 95 Moving means 95a Operation switch 95b Conversion mechanism 95c Control circuit 95d Motor 96 Moving means 96a Operation switch 96b Reciprocating mechanism 96c Control circuit 96d Motor 97 Moving means 98 Detecting means 99 Moving means 99a Operation Knob 99b Conversion mechanism E Eye to be inspected Sa, Sa 'Anterior eye observation optical system Sb Working distance index projection optical system Sc Working distance detection optical system Sd Fundus photographing optical system Sd1, Sd2, Sd3 Optical system

Claims (7)

[Claims] 1. A fundus photographing optical system comprising: a fundus photographing optical system for photographing a fundus of an eye to be examined; a diopter index; and a moving means for moving the diopter index in a direction in which the diopter changes. A fundus photographing apparatus in which a focus adjusting unit that adjusts the focal point of the fundus photographing optical system adjusts the focus of the fundus photographing optical system in accordance with the diopter of the diopter index that changes with movement in conjunction with the moving unit. 2. The apparatus according to claim 1, further comprising a detecting unit configured to detect a variable that changes in accordance with the position of the diopter index, wherein the focus adjustment unit adjusts the diopter of the diopter index based on an output of the detecting unit. The fundus imaging apparatus according to claim 1, wherein the apparatus is driven to adjust the focus of the fundus imaging optical system. 3. The fundus according to claim 1, further comprising an anterior segment observation optical system for observing an anterior segment of the eye to be examined, wherein the diopter index is incorporated in the anterior segment observation optical system. Shooting equipment. 4. The method according to claim 1, wherein the moving unit includes an operation unit, and the diopter index moves according to an operation of the operation unit.
4. The fundus photographing apparatus according to any one of 3. 5. The fundus photographing apparatus according to claim 1, wherein said moving means is a manual device. 6. The apparatus according to claim 1, wherein said moving means includes a power unit for moving said diopter index.
Item 8. A fundus photographing apparatus according to item 1. 7. An fundus imaging optical system which projects an alignment index light onto the eye to be inspected, receives an ocular reflection image of the alignment index light by an anterior ocular segment observation optical system, and follows the ocular reflection image. The fundus imaging apparatus according to any one of claims 1 to 6, further comprising an alignment unit that automatically performs alignment of the fundus.