JPS5977829A - Eye bottom 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 effectively eliminates flare and ghosts caused by the reflection and scattering of illumination light on the cornea and crystalline lens of the eye to be examined during observation and photography of the peripheral part of the fundus, thereby producing a good fundus image. This invention relates to a fundus camera that enables observation and photography.

The surfaces of the cornea and crystalline lens have the property of reflecting light, while the interior thereof has the property of scattering light. Therefore, when the illumination light flux passes through the cornea and crystalline lens, a reflected and scattered light flux is generated, which is different from the observation/photography light flux.
- When the light enters the fundus camera and reaches the finder or film, it creates flare and ghost, so in order to observe and photograph a good eye image, it is necessary to combine the reflected and scattered light flux and the observation/photography light flux. must be separated in some way. Therefore, for example, patent application No. 56-18474
In the fundus camera described in No. 1, an annular aperture, a central light-shielding plate, an aperture diaphragm, etc. are provided in the illumination optical system of the fundus camera body, and respective images are projected onto the eye to be examined by the illumination optical system and objective optical system. However, in the case of this fundus camera, when the optical axis of the fundus camera is tilted with respect to the optical axis of the eye to be examined in order to observe and photograph the peripheral part of the fundus, flare occurs in the peripheral part of the screen, making it difficult to obtain a good image. There were 9 problems in which fundus images were not observed and photographed. To explain this in detail, FIG. 1 shows the optical system of this conventional example, where 1 is the observation light i1! ,
2fd collector, lens, 3 is a light source for photography, 4 is a ring slit with an annular aperture, 5 is a central light-shielding plate, 6 is a relay lens, 7 is an illumination diaphragm, 8 is a sunspot plate with a light-shielding sunspot (objective) ), 9 is a mirror, IO is a relay lens, 1
1 is an aperture stop, 12 is a center shielding plate, 13 is a mirror support plate having an annular aperture, 14 is a mirror, 15 is an objective lens, 1
6 is an eye to be examined, 17 is a model supported by the wedge mirror support plate 13, 18 is a cylindrical diaphragm arranged around the wedge mirror 17, 19
20 is an aperture stop, 20 is a relay lens, 21 is a flip-up mirror that can be flipped up to switch the optical path to the film side of the optical axis during shooting, 22 is a mirror, 23 is a focus plate, 24 is an eyepiece lens,
25 is a roof prism rotatable around the optical axis for switching the photographing optical path, and 26 is a film surface. The light beam emitted from the observation light source 1 is sent to the photography light source 3 through the condenser lens 2VC.
Since the light is once condensed, the light beams emitted from both light sources 1 and 3 illuminate the ring slit 4 from behind.

Illumination light fluxes U and I that have passed through the annular opening of the ring slit 4
J Sirens 6. Mirror 9. relay lens l.

As a result, an annular aperture image of the ring slit 4 is created within the annular aperture of the wedge mirror support plate 13. During this time, the illumination light flux is transmitted to the center light shielding plate 5. Teruno aperture7. Black spot board 8. Aperture stop 11. Part of the light is blocked by the center light blocking plate 12. Wedge mirror support plate 13
The illumination light beam emitted from the annular aperture image of the ring slit 24 in the annular aperture is further reflected by the mirror 14 and reflected again by the objective lens 15 near the front surface of the crystalline lens of the eye 16 as the annular aperture image of the ring slit 40. It forms an image and illuminates the fundus of the eye. The image of the illuminated fundus passes through the iris (pupil) of the eye 16 to be examined, and is focused by the objective lens 15 near the focal position on the rear side. This fundus image passes through a cylindrical diaphragm, is reflected by a wedge mirror 17, and then passes through an aperture diaphragm 19.

When observing the fundus, the flip mirror 21 is at the position shown in the figure, so the fundus image is formed by the relay lens 20° and the flip mirror 21. The mirror 22 refocuses the image on the focusing plate 23, and the image is magnified and observed through the entire eyepiece 24. In addition, since the flip-up mirror 21 is lifted up during photographing, the fundus image is reflected by the roof prism 15 and transferred to the film surface 2.
6 or 26'. Since this example of the prior application is constructed as described above, the images 5' and 12' of the two central light-shielding plates 5 and 12 are located at the center of the crystalline lens 16b and near the cornea 16a, as shown in FIG. The image 4' of the ring slit 4 is projected onto the front surface of the crystalline lens 161), and the image 11' of the aperture stop 11 is projected near the cornea 16a. The illumination light flux A and the observation/photography light flux B are projected as if they were projected images 11', 12/, 4. ', 5
The light beams A and B pass between the cornea 16a and the crystalline lens 16b of the eye 16 to be examined, as if restricted by Observation/photography luminous flux B vc
Therefore, harmful light such as reflected and scattered light generated in the cornea 16a and the crystalline lens 16b does not mix in, and as a result, flare, ghost, etc. do not occur.

However, even though fundus cameras have become wider in recent years,
In addition, it is still not possible to capture all the necessary area of the fundus in one photograph, so in order to observe and photograph the peripheral part of the fundus, the fundus camera is positioned with respect to the optical axis of the subject's eye 16 as shown in Figure 3. If the optical axis O' is tilted, flare will occur at the periphery of the screen, making it impossible to observe and photograph a good fundus image. That is, in this case, FIG. 4 shows the illumination light flux A and the observation/photography light flux B.
It is a cross-sectional view of the eye 16 to be examined showing how the eye passes through the inside of the eye to be examined, and as shown in the figure, the cornea 16a and the crystalline lens 16b are seen from the image 41 of the ring slit 4 on both sides of the optical axis 0' of the fundus camera. Each distance chick changes up to
As a result, on one side of the optical axis σ' of the fundus camera, the cornea 1
6a and the crystalline lens 16b, a region C occurs where the illumination light flux A and the observation/photographing light flux B overlap, resulting in flare at the periphery of the screen as shown in FIG. On the power side, the area where the illumination light flux A and the observation/photography light flux B overlap is the cornea 16a and the crystalline lens 16.
further away from b). Furthermore, when observing, detecting, and photographing the peripheral part of the fundus, the light flux passing through the anterior segment of the subject's eye tends to be partially restricted by the pupil, and to compensate for this, the amount of light per unit area of the illumination light flux is increased. However, if this is done, more harmful light will be generated in the area where the two light beams A and B overlap, resulting in even greater flare at the periphery of the screen.

Therefore, in order to completely prevent this phenomenon, the central light shielding plates 5 and 1 are
2. Ring slit 4. It has been considered to change the dimensions of each thin beam regulating member such as the aperture stop 11 or to move it in the direction of the optical axis, but this is not preferable because it involves a decrease in the amount of light.

In view of the above-mentioned problems, the present invention prevents the occurrence of flare without reducing the amount of light and sound when observing and photographing the peripheral part of the fundus by making the light beam regulating member movable in a direction perpendicular to the optical axis. The purpose of this invention is to provide a fundus camera in which the same parts as those in the conventional example described in 1.
6, the center light shielding plates 5 and 12 are arranged close to each other before and after the ring slit 4, and the center light shielding plate moving device 27 moves the optical axis. It can be freely moved in a direction perpendicular to the . Further, a condensing lens 28 is arranged between the photographing light source 3 and the center light shielding plate moving device 27. FIGS. 7 and 8 show the structure of the center light shielding plate moving device 27, in which 29 is a cross-sectional square-shaped glue with a ring slit 4 fixed to the center hole, a Geslit support, and 30 and 31 are ring slit supports. A dovetail groove 30a is fixed to the front and rear of 29 and extends in the radial direction.

31a and a central hole 30b, 31b, and is rotatably supported by the fundus camera body 32 around the optical axis (FIG. 8); 33 and 31j: central light shielding plates 5 and 12 in the central hole; dovetail-shaped gobo plate supports 35 and 36 are fixed to the dovetail grooves 30a and 31a of the rotating bodies 30 and 31, respectively, and are movably inserted into the dovetail grooves 30a and 31a of the rotating bodies 30 and 31, respectively. Racks 37 facing each other fixed in a state parallel to their moving direction, that is, the radial direction, are pivotally connected to the bottom plate portion 29a of the ring slit support 29, and gears 38 are meshed with both the racks 35 and 36. is the bottom plate part 29aK of the ring slit 29
A pinion 38a that is pivotally connected and provided at the tip is connected to the gear 3.
7vc+a combined operation knob. and,
Operation knob 38'f: When rotated, the binion 38a,
Gear 37. Shade plate support 3 via racks 35 and 36
3 and 34 are moved in opposite directions to each other in a direction orthogonal to the optical axis. Therefore, the two central light blocking plates 5 and 12 are also moved in opposite directions in the direction VC perpendicular to the optical axis. Furthermore, since the rotating bodies 30 and 31 are rotatable around the optical axis, the two central light shielding plates 5 and 12
can be moved in any direction in a plane perpendicular to the optical axis.

Since the fundus camera according to the present invention is configured as described above, the two center light shielding plates 5 and 12 are moved to the optical axis by operating the operating knob 38 of the center light shielding plate moving device 27 during observation of the peripheral part of the fundus and HD imaging. When these projected images 5' and 12' are moved in mutually opposite directions in orthogonal directions, these projected images 5' and 12' also move in mutually opposite directions in orthogonal directions to the optical axis Ol, as shown in FIG. Then, the illumination light flux A from the image 4' of the ring slit 4
The distance to the area where the observation/photographing light flux B changes and the area is removed from the cornea 16a and the crystalline lens 16b. Therefore, harmful light such as reflected and scattered light generated in the cornea 16a and the crystalline lens 16b does not mix into the observation/photographing light beam B, and as a result, flare, ghost, etc. do not occur. Therefore, a good fundus image as shown in FIG. 10 can be obtained, and the entire screen (all angles of view) can be used as an effective photographing range.

In the above embodiment, the two center light shielding plates 5 and 12 are configured to be moved simultaneously by the same amount in opposite directions, but unlike this, the two center light shielding plates 5 and 36 are moved simultaneously by the same amount.
An intermediate gear having a different number of teeth may be interposed between the and the gear 37 so that the two center light shielding plates 5 and 12 move by different amounts.Also, the two center light shielding plates 5 and 2 may each move independently. It is also possible to make it so that only the one that acts effectively can move. Also, other light beam regulating members may be moved. Although not shown, the light beam regulating section may be moved in conjunction with tilting the optical axis O1 of the fundus camera with respect to the optical axis of the eye 16 to observe and photograph the peripheral part of the fundus. , is even more effective.

As mentioned above, the fundus camera according to the present invention has extremely important practical advantages in that a good fundus image can be obtained when observing and photographing the peripheral part of the fundus, and the entire screen can be used as an effective photographing range. There is.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the optical system of a conventional fundus camera, Fig. 2 is a sectional view showing the state of passage of the illumination light flux and the observation/photographing light flux inside the subject's eye according to the conventional example, and Fig. 3 is a diagram of the peripheral part of the fundus. A diagram showing a state in which the optical axis of the fundus camera is tilted with respect to the optical axis of the eye to be examined for observation and photography, FIG. Figure 5 shows the fundus image in the case of Figure 4, Figure 6 shows the optical system of an embodiment of the fundus camera according to the present invention, and Figure 7 shows the fundus image in the case of Figure 4.
8 and 8 are respectively a perspective view and a front view of the center light shielding plate moving device of the above embodiment, and FIG. 9 is a case where the optical axis of the eye J-sharp camera is tilted with respect to the optical axis of the eye to be examined in the above embodiment. A cross-sectional view showing the passage state of both light beams inside the eye to be examined,
FIG. 10 is a diagram showing the fundus and image in the case of FIG. 9. 4...Ring slit, 5...Center light shielding plate, 1
1... Aperture stop, 12... Center light shielding plate, 16...
・Agent Yasushi Shinohara,',
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Claims (1)

[Claims] In a fundus camera in which an illumination optical path and an observation/photographing optical path are partially overlapped, and a light ray regulating member is placed in the illumination optical path to remove harmful light from the subject's eye, the light ray regulating member is arranged perpendicular to the optical axis. Fundus camera 0 characterized by being able to move in the vertical direction