JPS6068826A - Eyeground camera - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fundus camera suitable for general photography and fluorescent fundus photography.

Fluorescence fundus photography is one type of fundus imaging, in which the fundus is illuminated with excitation light of a wavelength near blue, timing the time when frioretsen sodium, etc. injected through the cubital vein reaches the intraocular circulation system, and detects the total fluorescence generated from the patient's body. This is performed by photographing only the fluorescence from the reflected light from the subject's eye. At that time, a barrier filter is installed in the photographing optical path and an exciter is installed in the illumination optical path to separate the wavelengths, so the amount of light decreases depending on the transmission characteristics of the filter, and the light is generated in the fundus. Because the emission rate of fluorescent light is significantly lower, a greater amount of illumination light is required than in general color photography.

On the other hand, in a fundus camera in which the imaging system and illumination system are arranged coaxially, a sunspot is provided in the illumination optical path to prevent part of the illumination system from reflecting off the cornea and entering the imaging system. A method of blocking reflected light in advance has been practiced for a long time.

However, recently.

As objective lenses have become wider (45°), harmful light reflected by the crystalline lens has become a problem. This is because with a conventional internal-angle fundus camera (30°), the sunspot shape, or image, covered not only the reflective area of the cornea but also the crystalline lens, but as the objective lens becomes wider, the shadow of the sunspot becomes shorter. This is because the crystalline lens also generates harmful light.

As a countermeasure to this, Japanese Patent Publication No. 51-24249 proposes to form a sunspot image on the front surface of the crystalline lens or between the front and rear surfaces to eliminate the light reflected by the crystalline lens surface.
No. 7140 provides a sunspot in the illumination system that is conjugate with the posterior surface of the crystalline lens to remove scattered light from the intravitreal lens and the posterior surface of the crystalline lens.

By the way, forming a sunspot image within the subject's eye means that the amount of illumination light is reduced accordingly.

This is inconvenient for fluorescence fundus photography.

On the other hand, since the angle of view of the fundus illumination system of the fundus camera is constant,
A certain range is always illuminated, and if variable magnification is possible, it is set to match the wide-angle side, so on the narrow-angle side, the area that is actually photographed may be illuminated. There is.

Furthermore, in the case of a concave surface such as the fundus, the scattered reflected light generated in the periphery can easily cause ghosts or flares. This type of problem can be removed by blocking light around the area where the light is being exposed.

An object of the present invention is to eliminate harmful light generated by the eye to be examined and to increase the amount of illumination light when performing special photography.

A first embodiment will be described below with reference to the drawings.

In the figure, E is the eye to be examined, Ef is the fundus, Ec is the cornea, and Ep is the pupil. Reference numeral 1 denotes an objective lens, which is set at a certain distance from the eye E to be examined and has a function of forming a fundus image. Reference numeral 2 denotes a perforated mirror with an aperture Ej2a, and the aperture 2a functions as a photographic diaphragm. 3 is a 7-occurring lens % 4 is a fixed lens 5 is a relay lens % 7 and 8 are lenses that move for variable magnification, and the lenses 3 to 8 constitute a variable magnification imaging system.

9 is the shutter, 10F! In a photographic film, the above-mentioned members 1 to 10 constitute a photographing system.

In addition, in the shooting system 7 focusing, the optical path length between the relay lens 5 and the film 10 may be changed, and in the variable magnification imaging system, in addition to the zoom lens, lenses with different focal lengths are attached in a turret style. may also be adopted.

Next, 11 is a focus shaft, which is connected to a focus knob (not shown). Reference numeral 12 denotes a focus lever, which is fixed to the focus shaft 11 on one side and connected to the Z focus lens 3 with a long pin, so that the focus lens 3 moves in the direction of the optical axis when a focusing operation is performed.

Reference numeral 13 denotes a zooming shaft, which is connected to a zooming knob or a zooming motor, and a magnification small gear 14 is attached to this shaft.
is fixed. 15 is a variable power gear. Reference numeral 16 denotes a part of a cam ring, and a cam groove is formed on the tube, and each cam ring is engaged with a pin fixed to the lens group. The other side of the pin engages with a linear cam in the optical axis direction, but this is not shown. The variable power large gear 15 is fixed to the cam tube 16, and meshes with the variable power small gear 14 for driving, and when the variable power small gear 14 is rotated, the large variable power gear is driven and rotates to the cam tube. 16 to move the variable magnification lenses 7 and 8 along predetermined cam curves.

Next, reference numeral 17 is a flip-up mirror which is installed obliquely between the photographing lens 5 and the shutter 9 during observation, guides the finder light beam by reflection, and is retracted out of the photographing optical path during photographing. 18 is a field lens and the film 10 is arranged in substantially conjugate attachment with respect to the flip-up mirror 17. 19 is a mirror for changing the optical path, and 20 is an eyepiece. Further, 21 is a light source for observation such as an incandescent bulb, 22 is a condenser mirror, 23 is a first condenser lens, 24 is a light source for photography such as a strobe tube, and 25 is a second condenser lens.

Reference numeral 26 denotes a ring slit plate having an annular opening, and a light shielding area 26& in the center serves to form a shadow area through which photographing light passes. 27 is a black dot for shading.

For example, it is pasted on a transparent flat plate.

28 is a mirror for changing the optical path, 29.30 is a relay lens group, and perforated mirror 2 has the function of dividing photographing light and illumination light.
It is placed at the intersection of the optical axis of the imaging system and the optical axis of the relay lens group. The ring slit plate 26 and the pupil Ep of the eye to be examined are conjugate. In addition, the sunspot 27 is conjugate with the fundus-side surface of the crystalline lens FB when the angle of view is wide, and its dimensions are such that the area where the photographing light (the light beam reaching the film) passing through the fundus-side crystalline lens surface passes its shadow. Make it large enough to cover. The above members 21 to 30, the objective lens 1, and the effective mirror 2 constitute an illumination system.

With the above configuration, the light beam emitted from the observation light source 21 is converged onto the ring slit plate 26 via the first and second condenser lenses 23, 25, and illuminates it. The illuminated aperture of the ring slit plate 26 becomes an annular secondary light source and emits a light beam, which is reflected by the mirror 28, converged by the relay lens group 29 and 30, and then the hollow perforated mirror 2 Once a secondary light source image is formed on top of the
A secondary light source image is further formed on the pupil Ep, and the fundus Ef is uniformly illuminated over a wide range. Scattered reflection occurs in the illuminated fundus Ef, and the general reflected light passing through the aperture 2ai of the perforated mirror 2 passes through the central region of the secondary light source image, that is, the light-shielding area (image 26a), and exits the subject's eye. The light then enters the objective lens 1 and is imaged there, forming an intermediate image once. Next, the light flux passes through the central aperture 2a of the perforated mirror 2, enters the variable magnification imaging system (3 to 8), converges and emerges there, is reflected by the flip-up mirror 17, and forms a fundus image near the field lens 18. Since the fundus image is formed, the fundus image can be observed through the eyepiece lens 20.

Next, 50 is a field of view diaphragm, which uses an iris diaphragm with a variable aperture diameter so that the image can be sharpened later. The action of this aperture is the fundus E.
The purpose is to prevent harmful light from being mixed into the illumination light by covering the area hit by the illumination light with the image of the diaphragm, except for the part where f is photographed. Therefore, the position of this diaphragm must be conjugate with the fundus Ef regardless of the field of view of the eye to be examined, and at the same time, the diaphragm blades must be opened and closed in accordance with the angle of view of the limbus system.

Reference numeral 51 is a transmission member for the throttle opening/closing signal, which includes a non-stretchable flammable tube and a flammable release cable 5 that slides inside the tube.
1a, and can be assumed to be something like a cable release that can be attached to and detached from the shutter button of a camera. 5
Fix one end of the transmission member to the fundus camera housing with a 2Fi fixing hardware.

Reference numeral 53 denotes a cam surface contact, which is fixed to the tip of the cable 51. Note that both ends of the cable are made to have strong rigidity, so that the amount of feeding and feeding at one end is accurately transmitted to the other end. Reference numeral 54 denotes a peripheral cam plate, which is fixed to the zooming shaft 13 and rotates according to the zooming operation, and the amount of cam displacement is determined by the angle of view of the imaging system, that is, the range to be photographed on the fundus and the illumination by the aperture wheel 58. Decide so that the range of light blocking is harmonious.

A movable plate 55 is guided by a guide mechanism (not shown) and is movable in the optical axis direction of the illumination system, and the aperture plate 50 mentioned above is fixed thereto. This movable plate 55 is pin-long connected to the focus lever 12 described above, so that when the focusing lens 3 is moved by a focusing operation and the focus of the imaging system is aligned with the fundus Ef, the aperture is adjusted. 50 moves so as to be conjugate with the fundus Ef with respect to the relay lens 30, the perforated mirror 2, and the objective lens l.

56 is the other end of the signal transmission member 51 and is fixed to the edge of the movable plate 55. 57 is a connecting pin that connects the opening/closing member of the diaphragm 50 and the release cable 51a'ii.

Figure 2 shows the diaphragm and connecting pin viewed from above, Figures 3 and 4 show the view from the optical axis direction, and Figure 3 corresponds to a wide angle of view. When the diaphragm blades are opened, FIG. 4 shows the situation when the diaphragm blades are narrowed down to the maximum corresponding to the narrow angle of view.

In Figures 2 to 4, 59 is a sliding plate with a long hole 5 for guiding.
9a and 59b. Reference numerals 60 and 60' denote guide screws, which are screwed into the support of the diaphragm blades of the diaphragm fi50. The long holes 59a and 59b are loosely fitted into the guide screws 60 and 60',
As a result, the sliding plate 59 becomes movable in a direction perpendicular to the optical axis X.

6:1 is the opening/closing pin of the restrictor 50, and the hole 59c of the sliding plate 59
When the sliding plate 59 moves, the diaphragm 9 blades 50
a opens and closes. Reference numeral 62 denotes a lever, which is rotatably supported on a shaft 63, and this shaft 63 is connected to the upright portion 55a of the movable plate 55.
It is planted in b. An elongated portion 62a is provided at one end of the lever 62.

A pin 64 and an elongated hole 62 planted in the bent part of the sliding plate 59
L constitutes a pin/long coupling. The other end of the lever 62 is bent and comes into contact with the aforementioned connecting pin 57. A tension coil spring 65 is attached to a portion of the sliding plate 59 and the movable plate 55 so that the lever 62 is always in contact with the connecting pin 57, and always biases the lever 62 in one counterclockwise direction.

Next, the removal of scattered light and reflected light by the crystalline lens EB will be explained.

In FIG. 1, 74 is a black point moving cam, which is fixed to the zooming shaft 13. The amount of displacement of the cam is determined according to the change in the angle of view, and if no harmful light is generated by the crystalline lens at a narrow angle of view, the black spot 27 will be in the light-shielding area 2 of the ring slit plate.
6a and then the position of the black spot is determined for each angle of view so that no harmful light is generated even if the angle of view is expanded and the illumination light is not cut off unnecessarily. 71 is a member equivalent to the signal transmission member 51, and 71a is a release cable. 72jf; i, a fixing hardware for fixing the member 71ffi; 72a, the tip 7 of the release cable;
This is an adjustment screw for fully adjusting the position of 3. On the other hand, 81
is a supporting cylinder, which is fixed to a housing (not shown), through which an illumination optical path passes, and to which a ring slit plate 26 is attached. A projecting flat plate 81 A' is provided on the outside of the cylinder 81, and a hole is drilled in this projecting flat plate so that the other end 76 of the release cable 71a of the signal transmitting member 71 projects. The end 75 of the member is a flat plate 8
It is fixed at 1a. 77 is a slide plate, 78 is a slide shaft, and both are integrated.The slide shaft 78 is
Guide holes 81b and 81c provided in a part of the support cylinder 81
can be slid in parallel to the optical axis of the illumination system. On the other hand, as shown in FIG. 1 and FIG. 5, a black dot 27 for shielding light is fixed to one end of the slide shaft 78 via a fixed metal fitting 80. that time.

In order to place the black dot 27 inside the cylinder 81, one cylinder is provided with long grooves 81a and 81b parallel to the optical axis, and the fixed metal fitting 8
0 legs 80a and 80b pass through the long grooves 81a and 81bt, respectively. 79 is a return coil spring, which is disposed between the protruding plate 81 & from the cylinder 1 and the black dot fixing hardware 80;
When the coil spring expands and the legs 80a, 80b of the fixed hardware come into contact with one end of the long grooves 81a, 81b, the black dot 27 becomes conjugate with the fundus side of the crystalline lens Es, but the zooming shaft 13 rotates and the cam 74 rotates. Rotate and the end of the cable 73
When the cable is pushed into the circumferential surface of the cam 74, the other end 76 of the cable protrudes by that amount and pushes down the slide plate 77 and slide shaft 78. As a result, the black dot fixing hardware 80 resists the return spring 79. and move.

At this time, when the imaging system takes a narrow angle of view, the cam lift of the cam 74 is at its maximum and the cable end 76 protrudes the most, so that the black dot 27 approaches the ring slit plate 26 most.

Next, in this figure and FIGS. 6 to 8, 82-2 is an exciter, and the exciter 82-2 is fixed to the filter frame 83. The filter frame 83 is connected to the guide groove 81 of the support cylinder 81.
d, and can be slid in a direction perpendicular to the plane of the first figure, and can be freely slid from the outside. ) is attached and inserted into the optical path so that the optical path length between the slit plate 26 and the condenser lens 25 does not change even when the exciter 82-2t is removed from the optical path. Further, reference numeral 85 is a roller, which is rotatably supported on the bent portion of the slide plate 77.
4 is a cam plate, the side surface of which engages with the rollers 85; The cam plate 84 is fixed to the filter frame 83 as shown in FIG.
When the exciter 82-2 is inserted into the illumination optical path, the roller 85 contacts the trough 84a of the cam plate 84, and when the exciter 82-2 is inserted into the illumination optical path, the roller 85 contacts the crest 84b of the cam plate. come into contact with

Therefore, as shown in Fig. 6, when the parallel plate 82-1 is inserted and normal photo-taking is carried out, the position of the sunspot 27 is important, and the cable is The tip 76 of the cable protrudes to determine the position of the sunspot 27 on the optical axis, and if the angle of view becomes the widest angle, the optical end 76 of the cable is retracted the most, and the trough 84a of the cam plate 84 and the roller 85 come into contact. . On the other hand, as shown in Fig. 7, exciter 82-2
is inserted, and at the same time the barrier filter 8 shown in Fig. 1 is inserted.
8 is inserted into the photographing optical path, there is no need to block the crystalline lens with sunspots. This is because, as is well known, the exciter and barrier filters have different transmission wavelength ranges.
This is because even if the light that has completely passed through the exciter is reflected and scattered by the crystalline lens and mixed into the photographing light, it will be blocked by the barrier filter. Therefore, as the filter frame 83 moves, the cam plate 84 pushes down the cog5'lz, and the slide plate 7
Since τ and the slide plate 78 are transferred against the spring 79,
Black spot 27t - brought close to ring slit plate 26. When the ridge 84b of the cam plate 84 and the roller 85 engage, the slide plate 77 moves farthest away from the optical end 76 of the cable.
Even if the imaging system is set to an included angle and the tip 76 of the cable protrudes the most, it will not push the slide plate 77. Incidentally, the sunspots can also be transferred in conjunction with the attachment of the barrier filter.

With the above configuration, when the general examiner as shown in FIG. 1 looks through the eyepiece 20 to observe the fundus and performs a focus operation, the focus shaft 11 rotates and the focus lever 12 also rotates. Focusing lens 3 moves. Note that during normal photographing, the exciter 82-2 and the barrier filter 88 are kept out of the optical path.

When the system focuses on the fundus, the examiner stops the focusing operation and leaves the focusing lens 3 still at that position. At this time, the moving plate 55 is moved by the rotation of the focus lever 12, and is conjugately related to the aperture #)50t and the fundus Ef.

On the other hand, when a zooming operation is performed and the zooming shaft is rotated, the small gear 14 rotates, and the large gear 15 that meshes with the small gear 14 rotates to drive the cam tube 16.

The variable magnification lenses 7 and 8 move in a predetermined relationship to change the focal length or angle of view of the variable magnification imaging system by a desired amount. At the same time, the cam plate 54 also rotates to push down the contact 53 or allow the contact 53 to rise, releasing the release cable 51 &
moves in the axial direction, the connecting bottle 57 also protrudes or retracts.

The lever 62 in FIG. 3 rotates depending on the amount of movement of the connecting bin 57 in and out, and the sliding plate 59 also moves.

The opening/closing pin 61 also swings, and the aperture blade 501L is closed or opened.

Furthermore, when the cam plate 54 is rotated, another cam plate 74 also rotates, pushing down the tip 73 or raising the tip 73, and the release cable 71a moves in the axial direction. Also protrudes or retracts.

Therefore, the slide plate 77 and the shaft 78 move according to the amount of movement of the tip 76 in and out, and the black dot 27 occupies a different position depending on the angle of view.

In this way, when the imaging system is set to a wide angle (short focal length), the diaphragm blades 50a are opened and the entire imaging field on the fundus is illuminated with illumination light, and the sunspot 27 is a source of harmful light to the crystalline lens. When this is prevented and the narrow angle (long focal length) is set, the aperture blades 50a are narrowed down.

By covering the area to be photographed with the shadow of the diaphragm, the sunspot will no longer block illumination light. In addition.

Even at each intermediate angle of view, the area is covered as the angle of view around the continuously changing photographing angle of view changes.

Also, as mentioned earlier, when the lens is mounted in a turret style, the angle of view changes discontinuously, so it goes without saying that the movement of the sunspot and the opening and closing of the aperture are also discontinuous. In some cases, when an exciter is attached, the sunspot moves and blocks the illumination light, occupying a blank position.

According to the present invention described above, it is possible to diagnose occlusions that occur during wide-angle photography. This has the effect of making it possible to utilize the light amount of the luminous flux as effectively as possible and eliminating wasteful use of the amount of power supplied.

[Brief explanation of the drawing]

FIG. 1 is an optical sectional view showing an embodiment. FIG. 2 is a top view showing the aperture drive section. Figures 3 and 4 are respectively. FIG. 5 is a front view showing the aperture drive section, and FIG. 5 is a perspective view showing the black spot drive section. FIG. 6 and FIG. 7 are cross-sectional views showing the sunspot driving section. 8th
The figure is a perspective view of the filter frame. In the figure, 3 is the focusing lens, 12 is the focus lever, 27 is the black dot, 50 is the aperture), 51 is the aperture opening/closing signal transmission member, 71 is the black dot movement signal transmission member, 77 is the slide plate, and 78 is the slide shaft. is a return spring, 82-2 is an exciter, 83 is a filter frame, 84 is a cam plate, 8
8 is a barrier filter. Applicant Canon Co., Ltd.

Claims (1)

[Claims] A fundus camera that selectively performs general photography or fluorescence photography of the fundus of the eye to be examined is equipped with a light shielding object installed at a predetermined position in the illumination optical path during general photography to remove harmful reflected light from the eye to be examined; A fundus camera characterized by comprising means for changing a predetermined member during fluorescence photography with respect to photography, and means for moving the light shielding object in the optical path direction in conjunction with the means.