JPH08275921A - Fundus oculi camera - Google Patents

Abstract

PURPOSE: To automate operation by improving troublesome alignment to an eye to be examined and operation to adjust an actuating distance in photographing of the fundus by a fundus oculi camera. CONSTITUTION: An infrared light LED 21 for alignment and an infrared light LED 31 to detect an actuating distance are alternately lighted, and the alignment index light is projected on an eyeball surface 2 through an objective lens 5 of a fundus oculi photographing optical system, and its reflected light is received by a telecamera 30 of a front eye part observing optical system, and a photographing system 3 is guided in the XY direction on the basis of a position of a reflected image on an image pickup image screen, and the actuating distance detecting idex light is projected on the eye ball surface, and its reflected light is received by a light receiving element 37, and the photographing system 3 is guided in the Z direction until an actuating distance is detected, and alignment and an adjustment of the actuating distance are automatically performed. Afterwards, a concave lens 26 and a mirror 25 are retreated from an optical path, and a lamp 38 for an AF index is lighted, and the reflected light of the AF index from the fundus oculi is received by a telecamera 10, and a focus lens 7 and a member interlocking with it are scanned, and a focal adjustment is detected by an added focal adjustment detecting circuit, and a stroboscope 11 is made to emit the light, and the fundus oculi is photographed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus camera for photographing a fundus retina of an eyeball of a subject, and more particularly, to improve operations of alignment and working distance adjustment of a fundus photographing optical system. The present invention relates to a fundus camera designed for automation of operations.

[0002]

2. Description of the Related Art In recent years, fundus photography has become widely used in medical examinations because many useful medical findings such as arteriosclerosis and hypertension can be obtained. This fundus photography
The subject's eye is guided to a fixed position by a fixation target, illumination light is introduced into the fundus through the pupil of the subject's eye, and the fundus is photographed through the pupil. For this purpose, it is necessary to match the optical axis of the imaging device and the optical pupil with the optical axis of the eye to be inspected and the pupil, that is, to perform “alignment” and “working distance adjustment”. In the past, an examiner operated the position of the optical system in the XYZ directions with a joystick or the like, depending on the state of a finder image or a monitor image of a photographing device, to perform the “alignment” and “working distance adjustment”.

This "alignment" and "working distance adjustment"
The operation requires skill, and in order to improve the operability, a manual guide that also serves as "working distance adjustment" for the "alignment" has been proposed, for example, as shown in Japanese Patent Publication No. 56-5533. As for the photographing apparatus, as shown in Japanese Patent Publication No. 58-43090, alignment of a housing equipped with a photographing system in the vertical / horizontal direction and adjustment in the front / rear direction can be performed to align the eye with a fundus camera and the like and the eye to be examined. There has been proposed an ophthalmologic apparatus provided with an adjusting system capable of accurately adjusting a working distance which is an interval. In addition, in order to improve the accuracy of automatic alignment and automatic focusing in the fundus camera, the fixation target that is unnecessary during automatic alignment and the projection index light for focusing are dimmed and unnecessary during automatic focusing. Japanese Patent Application Laid-Open No. 5-95907 discloses a light source for detecting a fixation target and a working distance.

[0004]

However, not only the fundus camera which is normally used in the past, but also the fundus camera which can accurately perform the alignment and the working distance alignment of the improved type can be used. The adjustment and the adjustment of the working distance require a troublesome operation, and each of them requires considerable time and skill before shooting. Further, although a fundus camera provided with the above-mentioned automatic alignment or automatic focusing device has been proposed, none of them automatically adjusts an operating distance as compared with automatic alignment, and further does not continuously operate by automatically focusing.

The present invention has been made in view of the above circumstances, and improves troublesome operations such as "alignment" and "working distance adjustment" without requiring labor and learning, and the head of the subject is improved. We provide a fundus camera that can automatically perform alignment and working distance to the subject's eye simply by fixing the target to the jaw table and then fixing the target with the subject's eye and operating the machine. In addition, it is an object of the present invention to provide a fundus camera capable of continuously performing focusing and performing fundus imaging.

[0006]

In order to achieve the above object, in a fundus camera of the present invention, an illumination optical system for illuminating the fundus of an eye to be inspected and a fundus for illuminating the fundus by a television camera. A fundus imaging optical system that is designed to capture images, an alignment index projection optical system that projects an alignment index onto the ocular spherical surface through the objective lens of the fundus imaging optical system, and the anterior segment can be observed through the objective lens of the fundus imaging optical system as well. The anterior segment observation optical system, means for guiding the fundus imaging optical system in the direction of the eye to be examined based on the corneal reflection image position of the alignment index observed with the anterior segment observation optical system, and the anterior segment observation optical system. An optical path switching means for switching the optical path of the fundus photographing optical system is provided.

In order to detect the working distance of the fundus photographing optical system, a working distance detection index projection optical system for projecting an alignment index and an index alternately lit toward the eye to be examined,
Working distance detection means for detecting the working distance based on the reflected light from the cornea of the working distance detection index, and guiding the fundus imaging optical system toward the eye to be examined until the working distance detection means detects the corneal reflected light of the working distance detection index It is expedient to provide the fundus camera with means for doing so.

Further, the fundus camera has a focusing index projection optical system for projecting a focusing index on the fundus to detect focusing, an optical system for observing the focusing index projected on the fundus, and a focusing. It is effective to provide means for detecting the in-focus state based on the state of the fundus reflection image of the index. The means for detecting the in-focus state can be provided manually or automatically.

When the optical paths of the anterior ocular segment observing optical system and the fundus photographing optical system are switched by the optical path switching means, during alignment used in the anterior ocular segment observing optical system as a fixation target,
Also, it is desirable to provide a pair of left and right fixation targets for use in focusing / imaging in the fundus photographing optical system in the fundus camera.

[0010]

According to the fundus camera of the present invention, by adopting the configuration described in claim 1, the alignment index is projected from the alignment index projection optical system onto the ocular surface of the eye through the objective lens of the fundus photographing optical system, and the alignment index is projected through the objective lens. Observe the anterior segment with the eye observation optical system, and based on the corneal reflection image position of the alignment index on the observed anterior segment image, easily and automatically by means for guiding the fundus imaging optical system in the direction of the subject's eye. While the alignment can be performed, the optical path switching means can switch the optical path after the objective lens to switch the anterior ocular segment observation optical system and form the fundus imaging optical system. It is possible to automatically perform fundus photography.

The retinal camera is provided with a working distance detection index projection optical system for projecting an index that is turned on alternately with the alignment index toward the eye to be examined, and the working distance detection means causes the reflected light from the cornea of the working distance detection index. By providing a means for guiding the fundus photographing optical system in the direction of the eye to be examined until the working distance detecting means detects the corneal reflected light of the working distance detecting index by detecting the working distance based on By eliminating the interference of the two index lights with the distance detection index, the alignment can be controlled simultaneously (alignment tracking) even during the "working distance matching" operation, and the working distance can be adjusted. Can be done automatically.

A focusing index projection optical system for projecting a focusing index on the fundus is provided in the fundus camera so that the focusing index projected on the fundus is observed by the optical system for observing the focusing index. By providing a means for detecting the in-focus state based on the state of the fundus reflection image of the index, it is possible to easily and accurately perform the focus regardless of whether the detecting means is manual or automatic. In this case, the optical system for observing the focus index can be combined with the fundus photographing optical system.

Further, by providing the fundus camera with two pairs of left and right fixation targets for alignment and fundus focusing / photographing, which are used when switching the optical paths of the anterior segment observation optical system and the fundus photographing optical system, Even if is switched, the fixation target can be presented to the subject at the same position through the objective lens, and the subject's eye can be stabilized.

[0014]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows an optical path diagram of the embodiment, and FIGS.
4A and 4B are explanatory diagrams showing the optical paths of the fixation target during left eye alignment and left eye focusing / imaging in the embodiment of FIG. 1, respectively, and FIG. 4 is a block diagram of the embodiment.

In FIG. 1, an illumination optical system for illuminating the fundus of the eye 1 to be inspected and a fundus photographing optics for allowing the television camera 10 to observe or photograph the fundus on the basis of the illumination light illuminating the fundus. System, an alignment index projection optical system for projecting an alignment index onto the ocular spherical surface 2 through the objective lens 5 of the fundus photographing optical system, and an anterior eye that also allows the anterior segment to be observed by the television camera 30 through the objective lens. Working distance detection index projection optical system for projecting an index that alternately turns on the alignment index through the optical axis 4 of the partial observation optical system and the fundus imaging optical system to the eye to be inspected, and a working distance detection index Of the reflected light from the cornea of the, the working distance detection optical system for detecting the working distance, which is the distance between the fundus imaging optical system and the pupil of the eye to be examined, and the focus index is projected on the fundus. An imaging system 3 including a focusing index projection optical system for the purpose is shown, and the anterior segment observation optical system and the fundus imaging optical system are optical path switching including a concave lens 26 and a mirror 25 behind the objective lens 5. By switching the optical path by inserting / retracting a member (enclosed by a broken line) into the optical path of the fundus photographing optical system, it is possible to switch between alignment and focusing / photographing, and the optical system 3 uses the light of the fundus photographing optical system. It is moved in each of three directions, that is, the Z direction that is the direction of the axis 4 and the X and Y directions that are orthogonal to the optical axis, by a drive mechanism described later.

As a light source for illuminating the fundus of the eyeball 1, the strobe discharge tube 11 used for photographing the fundus retina and the halogen lamp 38 used for focusing of the fundus photographing optical system collect light from a common illumination optical axis 16. Light lens 20
Through a perforated mirror 6 (the outer shape is circular due to the centering of the hole) and passes through the objective lens 5 along the retracted optical axis 4 of the concave lens 26 and the mirror 25 for anterior ocular segment observation alignment. The cornea reflected light is excluded and enters the eye 1 to be inspected.

Visible light emitted from the stroboscopic discharge tube 11 for photography is focused on the position of the circular slit 14 by the condenser lenses 12 and 13, and then passes through the circular slit 14 to pass through the mirror 15.
Is reflected on the illumination optical axis 16 by being bent by the flat glass 17, condenser lens 18, half mirror 19, condenser lens 20.
The image of the circular slit which is focused near the perforated mirror 6 is formed on the perforated mirror 6, is reflected by the mirror 6, and passes through the retracted optical axis 4 of the concave lens 26 and the mirror 25. The light passes through the objective lens 5 of the fundus photographing optical system, is focused at the corneal vertex position, passes through the pupil position of the eyeball 1 (the position of the iris diaphragm), and illuminates the fundus retina surface of the eyeball 1. The positions of the strobe discharge tube 11, the circular slit 14, and the apex of the cornea of the eyeball 1 are in a conjugate relationship. That is, the illumination light enters the eye to be inspected only from the ring-shaped passage of the circular slit 14 and illuminates the fundus through the pupil. At this time, the reflected light from the center of the cornea is cut off and does not directly enter the objective lens.

In the fundus photographing optical system, an objective lens 5 is arranged on the optical axis 4 of the fundus photographing optical system which should be located on the eye axis so as to face the eye 1 to be examined and form an optical pupil in the pupil portion of the eye. It is set up. Then, a perforated mirror 6, a focus lens 7, and a relay lens 8 are sequentially arranged at predetermined positions on the optical axis 4, and a movable focus lens 7 (focus index projection optical system described later) is provided. When the fundus image is focused and formed on the CCD light receiving surface 9 on the front side of the rear TV camera (color TV camera for fundus imaging) 10 by adjusting the position of the eye fundus of the automatic focusing index light described later. The reflected light from is incident on the CCD light receiving surface 9 to detect the focus. Then, the index light for autofocusing is turned off and the strobe discharge tube 11 emits light to photograph a fundus image. In the present embodiment, the fundus focusing detection and the fundus imaging are performed by the CCD 9 of the same TV camera 10. However, the light receiving element for the fundus focusing detection uses the optical path of the fundus photographing optical system behind the focus lens 7. Alternatively, the focus may be detected by the focus detection CCD or PSD arranged on the branched optical axis.

In order to make index light for autofocus incident on the eye 1 to be inspected, a focusing index branched laterally parallel to the optical axis of the fundus photographing optical system with respect to the half mirror 19 provided on the illumination optical axis 16. Converging lens at predetermined positions on the optical axis of the projection optical system
44, a pair of left and right fixation targets 43L, 43R, split prism 4
2, a projection lens 41, an autofocus index slit 40, a condenser lens 39, and a halogen lamp 38 which is an autofocus index light source are arranged. The light from the halogen lamp 38 integrally forms a movable portion of the focusing index projection optical system, and moves with the focus lens 7 on the optical axis 4 of the fundus photographing optical system. , The autofocus index slit 40, the projection lens 41, the split prism 42, the condensing lens 44, the half mirror 19 to reflect the autofocus index light, and the focusing lens 20 on the illumination optical axis 16 After that, the light is reflected by the perforated mirror 6 and is reflected on the optical axis 4 (at this time, the concave lens
26 and the mirror 25 are retracted) The cornea reflected light is eliminated and enters the eye 1 through the objective lens 5.

The left and right fixation targets 43L and 43R move together with the focusing index projection optical system part that works in conjunction with the focus lens 7 during focusing and photographing by stroboscopic light emission, and the required fixation targets are examined. Present to the person. In FIG. 3, the left fixation target 43L is shown as a condenser lens 44 and a half mirror.
19 through the illumination optical axis 16 through the condenser lens 20, through the perforated mirror 6 on the photographing optical axis 4 correction concave lens 26 and the mirror 25
2 shows the state of the optical path when it is being presented to the eye to be inspected (left eye) through the objective lens 5 of the photographic optical system in which the optical path switching member is retracted.

An alignment index projection optical system for projecting an alignment index on the ocular spherical surface 2 through the objective lens 5 of the fundus imaging optical system for alignment of the fundus imaging optical system with the subject's eye 1 beside the fundus imaging optical system. Similarly, an anterior segment observation optical system is provided so that the anterior segment can be observed through the objective lens 5 of the fundus photographing optical system. That is, in order to switch the optical paths of the fundus photographing optical system and the anterior ocular segment observing optical system on the fundus photographing optical system optical axis 4 behind the objective lens 5, a strong objective lens is provided at a position close to the objective lens 5. A concave lens 26 with a strong correction for canceling the power and a mirror 25 for guiding the optical path laterally behind it are arranged at predetermined positions on the optical axis 4 so that they can be inserted and retracted, and the alignment index It constitutes a part of the projection optical system and the anterior segment observation optical system.

In the optical system for observing the anterior segment of the eye, the mirror 25 arranged so that it can be inserted into and removed from the optical axis 4 of the fundus photographing optical system without intersecting the optical axis 4 by 45 ° allows the optical system from the eye spherical surface 2 to move. The image light beam is bent in a direction perpendicular to the optical axis 4 and is directed to the fundus photographing optical system optical axis 4 from the half mirror 24 arranged on the optical axis 27 ₁ forming the bent anterior segment observation optical system. Lens for anterior segment photography on optical axis 27 ₂ folded in parallel
C of the monochrome TV camera 30 for alignment through 28
An image of the anterior segment is formed on the CD light receiving surface 29.

Further, in order to project the alignment index light onto the eye to be inspected from the optical axis 27 _{1 of the} anterior ocular segment observing optical system to the mirror 25, the light emitting diode 21 for the near infrared light which is the alignment index light. However, the optical path of the index light is bent by a mirror 22 arranged so that its optical axis is parallel to the optical axis 4 and on an extension of the optical axis 27 ₁ , and the condenser lens 23 and the half mirror The optical axis 4 of the fundus photography optical system through 24
By the upper mirror 25, from the optical axis 4 of the photographing optical system to the optical axis 4
The alignment index light is projected onto the eyeball surface 2 of the eye to be examined through the concave lens 26 inserted above and the objective lens 5. As a result, when the alignment index light is emitted from the light emitting diode 21 to the ocular surface of the eye, the reflected light is the CCD light receiving surface of the alignment monochrome television camera 30.
It is possible to detect the received light together with the anterior segment image on the 29. In detecting the alignment index light by the CCD light receiving surface 29, in order to eliminate mutual interference with the working distance detection index light described later, the working distance detection index light is alternately turned on and the alignment in the XY directions is synchronized with the lighting. Is detected (see FIG. 5).

The fixation target to be presented to the subject is a pair of left and right fixation targets 43L, which are used at the time of focusing and photographing.
With 43R, as the other pair of left and right fixation targets used during alignment, the optical axis 27 ₁ of the anterior segment imaging optical system is used.
Left fixation target 45L and right fixation target 45R are LE respectively.
It is provided at a predetermined position by D (see FIG. 2). At the time of alignment, the concave lens 26 and the mirror 25, which are optical path switching members for alignment and fundus photographing, are inserted on the photographing optical axis 4 behind the objective lens 5 of the fundus photographing optical system, and the fixation target 45L or 45R. Is reflected by the mirror 25 and is presented to the eye to be examined through the concave lens 26 and the objective lens 5.
Note that FIG. 2 shows the optical path when the left fixation target is presented to the left eye. In this way, by providing separate sets of fixation targets used for alignment / anterior segment observation and fundus focusing / imaging, the fixation target can be presented at the same position even when the optical path is switched. The eye to be examined can be stabilized.

In order to detect the working distance of the fundus photographing optical system with respect to the eye 1 to be examined, the working distance detecting index is set so as to have the optical axis 31 'inclined about 45 ° with respect to the optical axis 4 of the fundus photographing optical system with respect to the ocular spherical surface 2. A projection optical system is provided, and a working distance detection optical system is provided on the optical axis 35 in a symmetrical direction on the opposite side of the fundus photographing optical system optical axis 4 so as to detect corneal reflected light of working distance detection index light. Then, the working distance of the fundus photographing optical system is detected.

That is, an infrared light emitting diode (infrared LED) 31 which is a light source of the working distance detection index is provided at a predetermined position on the optical axis 31 'of the working distance detection index projection optical system,
The infrared light from the infrared light emitting diode 31 is collected by a condenser lens.
32, the working distance detection index slit 33, and the projection lens 34 enter the eye spherical surface 2, and the reflected light from the eye spherical surface (cornea) 2 travels on the optical axis 35 of the working distance detecting optical system and is condensed. lens
The light enters the light receiving element (PSD) 37 for detecting the working distance via 36 and detects the working distance of the fundus photographing optical system.
Further, the lighting of the infrared light emitting diode (infrared LED) 31 for the working distance detection index is turned on alternately with the lighting of the infrared light emitting diode 21 for the alignment index as described above at the time of alignment at the beginning of photographing. ing.
That is, as shown in the timing chart of the CCD for X / Y detection of lighting the alignment index and lighting the working distance detection index in FIG. 5, the two index lights of the alignment index and the working distance detection index do not interfere with each other. Even during the operation for adjusting the working distance, it is possible to adjust the working distance of the fundus imaging optical system while simultaneously controlling the alignment and continuing the alignment.

Next, a circuit for operating the photographing system 3 will be described with reference to the block diagram shown in FIG. The reflected light from the eye spherical surface 2 of the alignment index light caused by the lighting of the infrared light emitting diode (infrared LED) 21 for the alignment index (simultaneous lighting with the working distance detection index) is a TV camera of the anterior segment observation optical system (monochrome for alignment). TV camera)
An image is formed on the CCD light receiving surface 29 which is the image forming surface of 30, and the obtained image receiving signal is input to the image input / output control circuit 45. On the screen of the monitor display 47 which receives the video signal from the control circuit 45,
The light spot of the corneal reflected light of the infrared light for alignment from the eye spherical surface 2 is displayed together with the anterior segment image so that the alignment state at the above-mentioned stage of machine operation can be confirmed. In this case, the anterior segment image can be observed in room light,
The infrared LED may be used for illumination if necessary.

In the XY direction position detection control circuit 49 which receives the electric signal from the image input / output control circuit 45, the position of the light spot by the corneal reflected light on the image pickup screen, that is, with respect to the optical axis of the anterior segment observation optical system. The position of the light spot in the X and Y directions (corresponding to the position of the light spot in the X and Y directions with respect to the optical axis 4 of the fundus imaging optical system) is detected, and the light spot on the imaging screen is detected by the control signal by this position detection. So that it comes to the center of the screen,
The XY-axis mechanism 50 of the mount equipped with the imaging system 3 is driven to guide the mount.

When the XY direction position detection control circuit 49 detects that the light spot on the image pickup screen falls within a narrow predetermined range surrounding the center of the screen, for example, the control circuit 49
From the control circuit 51, the Z-axis drive mechanism 52 is operated by the drive signal from the control circuit 51, and the gantry equipped with the imaging system 3 is moved from the initial standby position to the eyeball of the eye to be inspected. The forward movement is started in the optical axis direction (Z direction) of the fundus imaging optical system toward 2, and at the same time, the XY axis drive mechanism 50 is driven to track the light spot.

In this way, the Z-axis is driven while tracking the light spot on the image pickup screen, and the working distance is increased during the forward movement of the photographing system 3 in the optical axis direction (Z direction) of the fundus photographing optical system. The light receiving element (PSD) 37 of the detection optical system is the infrared light emitting diode 31
When detecting the working distance detecting index light that has passed through the slit 33 from the working distance, the working distance is detected by the working distance detection control circuit 51 by the signal from the light receiving element 37 (the objective lens 5 of the fundus photographing optical system). When the optical pupil coincides with the pupil position of the eye to be inspected 1), the Z-axis drive mechanism 52 is stopped by the signal from the working distance detection control circuit 51, and at the same time, the XY-axis drive mechanism is received by the signal from the XY direction position detection control circuit 49. 50 stops and the gantry of the imaging system 3 stops moving.

At this time, the optical path switching mechanism 54 is driven by the signal from the working distance detection control circuit 51 via the optical path switching control circuit 53, and the concave lens 26 and the mirror 25 constituting the optical path switching member are formed.
And are retracted from the optical path of the fundus imaging optical system, and the alignment optical path is switched to the optical path of the fundus imaging optical system, and at the same time, the halogen lamp 38, which is an autofocus index light source, is turned on, and the focus is controlled by a signal from the focus detection circuit 55. The mechanism 56 is driven to interlock with the focus lens 7 on the optical axis 4 of the fundus photographing optical system, and the halogen lamp 38, the condenser lens 39, the autofocus index slit 40, the projection lens 41, the split prism 42, and the fixation target. The movable part of the focusing index projection optical system consisting of 43L and 43R,
Focusing is performed by moving each optical axis.

In this way, the television camera 10 for photographing the fundus of the fundus photographing optical system receives the reflected light of the focusing index from the fundus, and the received signal of the focusing index from the television camera 10 is input to the image. It is input to the focus detection circuit 55 via the output control circuit 45, and the focus of the fundus image is detected in the circuit 55. At the same time as this focus detection, the halogen lamp 38 of the focus index projection optical system
Is turned off to turn off the focus index, the strobe discharge tube 11 is caused to emit light by the signal from the focus detection circuit 55, and the fundus image is photographed on the light receiving surface 9 of the television camera 10. . Then, the image signal of the fundus from the TV camera 10 is passed through the image input / output control circuit 45 to the frame memory.
The fundus image is recorded (written) on 46, and the fundus image is displayed on the monitor display 47. Further, this fundus image can be read out from the frame memory 46 by the image input / output control circuit 45 as necessary, and can be shot out from the video printer 46, so that the image print of the eye to be inspected can be attached to the chart.

When the above photographing is completed, the photographing system 3 is automatically returned to the standby position. That is, at the end of photographing, the XY-axis drive mechanism 50 is reversely driven from the image input / output control circuit 45 via the XY-direction position detection control circuit 49, and
The Z-axis drive mechanism 52 is reversely driven by the signal from the direction position detection control circuit 49 via the working distance detection control circuit 51, and the photographing system 3 is set to the axial direction (Z direction) of the optical axis 4 of the fundus photographing optical system. The optical path switching mechanism 54 is driven by a signal from the working distance detection control circuit 51 through the optical path switching control circuit 53, and the concave lens 26 and the mirror 25, which are optical path switching members, are moved in the direction orthogonal to the axis. Optical axis 4 of fundus photography behind the lens
The camera is inserted above and returned to the initial state, and the photographing system 3 is put in a standby state.

Next, the operation procedure of the fundus camera according to the present invention will be described with reference to the flowcharts shown in FIGS. First, when the power button is turned on and the photographing button of the fundus camera in the standby state is pressed, an external image by the anterior ocular segment observation optical system is displayed on the monitor display 47. The examinee fixes his / her head on the jaw stand and looks at the fixation target through the objective lens 5 according to the doctor's instruction. At this time, the jaw base detects whether the eye to be inspected is the right eye or the left eye based on the relative position of the jaw base with respect to the objective lens 5, and a signal from the jaw base is provided to the observation optical system during anterior segment observation / alignment. A pair of left and right fixation targets 45L,
45R and a pair of left and right fixation targets 43L and 43R provided in the focusing index projection optical system at the time of fundus focusing / imaging are switched to the left or right fixation target (LED) corresponding to the eye to be lit. . Next, the doctor operates the jaw stand, adjusts the monitor display 47 so that the anterior segment of the subject's eye is displayed, and presses the photographing button again.

By this second button pressing operation, the alignment indicator infrared light emitting diode 21 as the alignment indicator and the working distance detection indicator infrared light emitting diode 31 as the working distance detection indicator are alternately turned on. Then, until the image (light spot) of the alignment index light due to the reflected light of the alignment index light from the cornea 2 can be recognized in the anterior segment image displayed on the image pickup screen of the alignment TV camera 30, Z
The axis is driven to move the photographing system 3 forward in the Z direction.

When the image (light spot) of the alignment index light is recognized on the image pickup screen of the television camera 40, it automatically enters a predetermined range of X / Y alignment at the center of the image pickup screen according to the position of the light spot. The X-axis and Y-axis are driven to move the imaging system 3 with respect to the eye to be inspected. Then, this state is displayed on the screen of the monitor display 47.

In this way, when the light spot of the alignment index light comes within a predetermined range at the center of the image pickup screen, the Z-axis is driven and the photographing system is driven while following the light spot within the predetermined range for alignment. 3 is moved in the Z direction until the working distance detection control circuit 51 detects the working distance detection index image.

During the forward movement of the photographing system 3 in the Z direction, when the working distance detection control circuit 51 detects the working distance detection index image (corneal reflected light) to detect the working distance, the X-axis / Y
The axis / Z-axis driving operation is stopped, the alignment index infrared light emitting diode 21 and the working distance detection index infrared light emitting diode 31 are turned off, and the optical path switching mechanism 54 is used.
Is driven to retract the concave lens 26 and the mirror 25 behind the objective lens 5 from the optical path of the fundus photographing optical system to switch the optical path of the anterior eye observation optical system and the optical path of the fundus photographing optical system. The halogen lamp 38, which is the auto-focus index light source of the system, lights up, and the halogen lamp 38, the condenser lens 39, the auto-focus index slit 40, the taking lens 41, the split prism 42, and the solid lens 42 which are integrally linked with the focus lens 7 are fixed. The movable part including the optotypes 43L and 43R is moved and scanned on the respective optical axes to detect the focus of the fundus image.

When the focus is detected, the halogen lamp 38 for the auto focus indicator is turned off, the stroboscopic discharge tube 11 emits light, and the fundus image is photographed by the color television camera 10 for photographing the fundus.
The photographed fundus image is recorded in the frame memory 46 and displayed on the monitor display 48, and then the photographing system 3 returns to the initial standby position and enters the standby state.

In this embodiment, the television camera 10 for photographing the fundus is used to receive and observe the autofocus index light for detecting the focus, but the optical path (optical axis) of the fundus photographing optical system is used. Condenser lens and CCD on the optical path (optical axis) branched from
It is also possible to arrange a camera or PSD to receive and observe the auto-focus index light to detect the focus. Further, when operating the fundus camera, the image from the television camera of the anterior ocular segment observing optical system may be displayed on the monitor by pressing the photographing button even after the head of the subject is fixed to the jaw stand.

[0041]

According to the fundus camera of the present invention as set forth in claim 1, the anterior ocular segment is observed and aligned through the objective lens of the fundus photographing optical system coaxially with the fundus photographing optical system. The optical paths of the anterior part observation optical system and the fundus imaging optical system are switched to perform alignment and fundus imaging, and the fundus imaging optical system is used for the fundus imaging optical system based on the alignment index position of the alignment index observed by the anterior segment observation optical system. Since it is guided in the direction, alignment can be easily and automatically performed with a simple configuration, and fundus imaging can be performed.

According to the second aspect of the present invention, in the fundus camera, alignment marks and working distance detection indices are prevented from interfering with each other, and alignment is performed during the "working distance matching" operation. Can be simultaneously controlled to continue the alignment, and the working distance adjustment can be easily automated.

According to the third aspect of the present invention, when the fundus camera is brought into focus, it can be easily and accurately focused by using the focus index projected on the fundus, either manually or automatically. it can.

According to the fourth aspect of the invention, in the fundus camera, even if the optical paths of the optical paths of the anterior ocular segment observation optical system and the fundus imaging optical system are switched, the left and right fixation targets are presented to the subject through the objective lens. Can be presented at the same position, and the eye to be examined can be stabilized and fundus imaging can be performed.

[Brief description of drawings]

FIG. 1 is an optical path diagram of an embodiment of the present invention,

FIG. 2 is an explanatory diagram showing an optical path of a fixation target when performing alignment by switching the optical paths.

FIG. 3 is an explanatory view showing an optical path of a fixation target when performing focusing / imaging by switching the optical paths.

FIG. 4 is a block diagram of an embodiment of the present invention,

FIG. 5 is a timing chart of lighting of an alignment index and lighting of a working distance detection index,

FIG. 6 is a flowchart showing the procedure of fundus imaging.

FIG. 7 is a flowchart showing a procedure following FIG.

[Explanation of symbols]

1 ... Eyeball, 2 ... Eye spherical surface (cornea), 3 ... Imaging system,
4 ... Fundus photographing optical system optical axis, 5 ... Objective lens,
6 ... perforated mirror, 7 ... focus lens,
9 ... CCD light receiving surface, 10 ... Color television camera for fundus imaging, 11 ... Strobe discharge tube, 14 ... Circular slit, 19 ... Half mirror, 21 ... Infrared light emitting diode for alignment index, 25 ... Optical path switching mirror,
26 ... concave lens for optical path switching correction, 29 ... CCD light receiving surface, 30 ... alignment TV camera, 31 ... infrared light emitting diode for working distance detection index, 37 ... light receiving element for working distance detection, 38 ... halogen lamp for auto focus index, 43L, 43R ... fixation target during focusing / imaging, 45L, 45R ... alignment target during alignment, 46 ... frame memory, 47 ... monitor display, 49 ... XY direction position detection control circuit, 50 ... XY axis drive mechanism , 51
... Working distance detection control circuit, 52 ... Z-axis drive mechanism,
53 ... Optical path switching control circuit, 54 ... Optical path switching mechanism, 55
... Focus detection circuit, 56 ... Focus control mechanism, 57 ... Strobe light emission control circuit.

[Procedure amendment]

[Submission date] May 16, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

In FIG. 1, an illumination optical system adapted to illuminate the fundus of the eye 1 to be inspected and a fundus photographing optics capable of observing or taking a photograph of the fundus by the television camera 10 based on the illumination light illuminating the fundus. System, an alignment index projection optical system for projecting an alignment index onto the ocular spherical surface 2 through the objective lens 5 of this fundus photographing optical system, and an anterior eye that also allows the anterior segment to be observed by the television camera 30 through the objective lens. Working distance detection index projection optical system for projecting an index that alternately turns on the alignment index through the optical axis 4 of the partial observation optical system and the fundus imaging optical system to the eye to be inspected, and a working distance detection index Detecting the reflected light from the cornea of, the working distance detection optical system for detecting the working distance which is the distance between the fundus imaging optical system and the pupil of the eye to be examined,
An imaging system 3 including a focusing index projection optical system for projecting a focusing index onto the fundus is shown. The anterior segment observation optical system and the fundus imaging optical system are the concave lens 26 behind the objective lens 5.
Optical path switching member consisting of mirror 25. and by the optical path switching by insertion and retraction of the optical path of the fundus photographing optical system (and surrounded by broken line), as well as to allow switching between alignment and focusing imaging, said imaging system Reference numeral 3 denotes a Z direction which is a direction of an optical axis 4 of the fundus photographing optical system, and X which is orthogonal to the optical axis.
-They are moved in the three directions of the Y direction by a drive mechanism described later.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

Next, a circuit for operating the photographing system 3 will be described with reference to the block diagram shown in FIG. Infrared light emitting diode (infrared LED) for alignment index 2
The reflected light from the eye spherical surface 2 of the alignment index light due to the lighting of 1 (simultaneous lighting with the working distance detection index) is the CCD which is the image plane of the television camera (monochrome television camera for alignment) 30 of the anterior segment observation optical system. An image is formed on the light receiving surface 29,
The obtained image receiving signal is input to the image input / output control circuit 45. On the screen of the monitor display 47 which receives the video signal from the control circuit 45, the light spot due to the cornea reflected light of the alignment infrared light from the eye spherical surface 2 is displayed together with the anterior segment image,
Whereby it is possible to check the alignment situation in the previous stages of mechanically actuated. In this case, the anterior segment image can be observed with room light, and may be illuminated with an infrared LED as necessary.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

In the XY direction position detection control circuit 49 which receives the electric signal from the image input / output control circuit 45, the position of the light spot by the corneal reflected light on the image pickup screen, that is, with respect to the optical axis of the anterior segment observation optical system. The position of the light spot in the X and Y directions (corresponding to the position of the light spot in the X and Y directions with respect to the optical axis 4 of the fundus imaging optical system) is detected, and the light spot on the imaging screen is detected by the control signal by this position detection. so you come to the center of the screen, by driving the XY-axis driving mechanism 50 of the equipped with gantry imaging system 3, so as to induce gantry.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction content]

As described above, the television camera 10 for photographing the fundus of the fundus photographing optical system receives the reflected light of the focusing index from the fundus, and the received signal of the focusing index from the television camera 10 is input to the image. Focus detection circuit 5 via output control circuit 45
5, and the focus of the fundus image is detected by the circuit 55. Simultaneously with this focus detection, the halogen lamp 38 of the focus index projection optical system is turned off to turn off the focus index, and a signal from the focus detection circuit 55 causes the strobe discharge tube 11 to emit light through the strobe light emission control circuit 57. At least TV camera 1
A fundus image is photographed on the light receiving surface 9 of 0. Then, the image signal of the fundus from the television camera 10 is supplied to the image input / output control circuit 4
5, the fundus image is recorded (written) in the frame memory 46, and the fundus image is displayed on the monitor display 47. The fundus image is read from the frame memory 46 by the image input / output control circuit 45 as necessary,
The image can be printed from the video printer 48, and the image print of the eye to be inspected can be attached to the chart.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction content]

Next, the operation procedure of the fundus camera according to the present invention will be described with reference to the flowcharts shown in FIGS. First, when the power button is turned on and the photographing button of the fundus camera in the standby state is pressed, an external image by the anterior ocular segment observation optical system is displayed on the monitor display 47. The examinee fixes his / her head on the jaw stand and looks at the fixation target through the objective lens 5 according to the doctor's instruction. At this time, the jaw base detects whether the eye to be inspected is the right eye or the left eye based on the relative position of the jaw base with respect to the objective lens 5, and a signal from the jaw base is provided to the observation optical system during anterior segment observation / alignment. A pair of left and right fixation targets 4
5L, 45R and a pair of left and right fixation targets 43L, which are provided in the focusing index projection optical system at the time of fundus focusing / imaging
43R is switched to one of the left and right fixation targets (LEDs) corresponding to the eye to be inspected and turned on. Next, the doctor operates the jaw stand, adjusts the monitor display 47 so that the anterior segment of the subject's eye is displayed, and presses the photographing button again.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

When the image (light spot) of the alignment index light is recognized on the image pickup screen of the television camera 30 , it automatically enters into a predetermined X / Y alignment range in the center of the image pickup screen according to the position of the light spot. The X-axis and Y-axis are driven to move the imaging system 3 with respect to the eye to be inspected. Then, this state is displayed on the screen of the monitor display 47.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

In this way, when the light spot of the alignment index light comes within a predetermined range at the center of the image pickup screen, the Z-axis is driven and the photographing system is driven while following the light spot within the predetermined range for alignment. 3 in the Z direction, working distance detection control circuit 51
There allowed to advance until it detects the working distance detection target image.

Claims (4)

[Claims] 1. An illumination optical system for illuminating a fundus of an eye to be inspected, a fundus photographing optical system for photographing a fundus by a television camera based on illumination light irradiating the fundus, and an eyeball through an objective lens of the fundus photographing optical system. Alignment index projection optical system that projects an alignment index on the surface, anterior segment observation optical system that allows observation of the anterior segment through the objective lens of the fundus imaging optical system, and alignment observed by the anterior segment observation optical system A means for guiding the fundus photographing optical system in the direction of the eye to be examined based on the corneal reflection image position of the index; and an optical path switching means for switching the optical paths of the anterior segment observation optical system and the fundus photographing optical system. Fundus camera. 2. An operating distance detection index projection optical system for projecting an alignment index and an index that alternately lights up toward the subject's eye to detect the operating distance of the fundus imaging optical system, and the operating distance detection index from the cornea. Working distance detecting means for detecting a working distance based on reflected light, and means for guiding the fundus photographing optical system in the direction of the eye to be examined until the working distance detecting means detects corneal reflected light as a working distance detection index are provided. The fundus camera according to claim 1. 3. A focusing index projection optical system for projecting a focusing index on the fundus, an optical system for observing the focusing index projected on the fundus, and a state of a fundus reflection image of the focusing index to determine the focusing state. The fundus camera according to claim 1 or 2, further comprising detection means. 4. The fundus camera according to claim 1, wherein two sets of fixation targets used when switching the optical paths of the anterior segment observation optical system and the fundus photographing optical system are provided.