JPS63194635A - Eye ground scanning apparatus - 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] [Industrial Application Field] The present invention projects and scans a bright spot such as a light source or an index onto the fundus of an eye to be examined, and receives reflected light from the fundus to extract fundus information. The present invention relates to a fundus scanning device.

[Prior Art] In conventional devices of this kind, when extracting the reflected light from the fundus of a bright spot projected on the fundus, an aperture diaphragm is fixedly arranged in the light receiving optical system, so that the angle of view can be widened. In this case, there is a drawback that scattered light from the cornea and crystalline lens is mixed into the image information, making it difficult to obtain a clear image.

[Purpose of the Invention] The purpose of the present invention is to improve the drawbacks of the conventional example, and to separate and remove scattered light from the cornea and crystalline lens, so that even when the angle of view is widened, a clear image can always be obtained. An object of the present invention is to provide a fundus scanning device that can perform the following functions.

[Summary of the Invention] The gist of the present invention for achieving the above-mentioned object is: a means for projecting and scanning a bright spot toward the fundus of an eye to be examined; a light receiving means for receiving a beam of light reflected from the fundus of the bright spot; The fundus scanning device is characterized by having a variable position light flux diaphragm that guides a luminous flux corresponding to the angle of view from the fundus according to a change in the angle of view of the projection of the bright spot onto the fundus.

[Embodiments of the invention] The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 shows an embodiment of a fundus scanning device according to the present invention,
E indicates the eye to be examined. 1 is a light source, and this light source 1
Along the optical axis, the light emitted from the ring slit plate 2 having a ring slit 2a and the third
As shown in the figure, a pinhole plate 3 with a pinhole 3a rotating around the optical axis, a relay lens 4, and a perforated mirror 5
is located. An objective lens 6 is arranged between the perforated mirror 5 and the subject's eye E, an aperture diaphragm 7 is provided near the hole of the perforated mirror 5, and an optical axis is provided behind the perforated mirror 5. As shown in FIG. 4, a position variable aperture diaphragm plate 8 having an aperture 8a that rotates around the optical axis, a projection lens 9, and a light receiving element 10 are arranged along the optical axis.

The light beam emitted from the light source 1 illuminates the ring slit plate 2 to extract a ring-shaped light beam, which further passes through the pinhole 3a of the pinhole plate 3 and reaches the relay lens 4 as a conical light beam.

Here, the pinhole 3a of the pinhole plate 3 is provided at a position eccentric from the optical axis 3C, and is rotatable about the optical axis 3c. The light that has passed through the relay lens 4 forms a ring slit image around the hole of the perforated mirror 5, and then is reflected by the perforated mirror 5 and enters the objective lens 6, where it enters the anterior eye of the subject's eye E. A ring slit image is again formed on the fundus Ef, and a pinhole image is formed on the fundus Ef. The light from the pinhole image reflected by the fundus Ef passes through the objective lens 6 again and passes through the aperture diaphragm 7 and the position variable aperture diaphragm plate 8 provided near the hole of the perforated mirror 5.
passes through the opening 8a. This aperture 8a is provided at a position eccentric from the optical axis 8c, and rotates around the optical axis 8C. The position of this aperture 8a corresponds to the angle of view and rotation angle of the pinhole 3a described above. Furthermore, the light passing through the aperture 8a is
The light is projected by a projection lens 9 onto a light receiving element 10 arranged at a position optically substantially conjugate with the pupil.

The dotted line shown in FIG. 5 shows the locus of the pinhole image on the fundus Ef of the eye E to be examined, and shows how the pinhole image rotates around the papilla and crosses blood vessels extending radially from the papilla. represents. Therefore, since the output detected by the light receiving element 10 changes depending on the intersections f1, f2, f3@... with the blood vessels, blood vessel coordinate information can be obtained from this output and the rotational deviation angle of the pinhole 3a. Become.

FIG. 6 shows the incident and exit states of the luminous flux in the anterior segment of the eye E, where the ring slit plate 2 and the aperture diaphragm 7 are projected approximately onto the iris, and 2° and 7° are the ring slits of the ring slit plate 2, respectively. It shows a two-tone image and an aperture stop image of the aperture stop 7. Further, the aperture 8a is conjugately projected to a slightly anterior position of the cornea, and 8' indicates its image. In FIG. 6, 3a' represents a pinhole image on the fundus Ef screen of the pinhole plate 3.

Here, the principle of removing scattered light from the cornea and crystalline lens of the eye E to be examined will be explained. In FIG. 6, the luminous fluxes α and β are meridional rays that are part of the ring-shaped illumination luminous flux,
Of the crystalline lens scattered light of these illumination light beams, the portions that can pass through the aperture stop 7 are Ll' to L1'' and L2' to L2''. However, since the aperture 8a of the position variable aperture diaphragm plate 8 is limited to the principal ray of the light beam from which the reflected light beam from the fundus Ef is taken out, it blocks scattered light. Therefore,
Even if the pinhole image 3a'' on the fundus Ef traces a trajectory, if the aperture 8a of the position variable diaphragm plate 8 is on the extension connecting the center of this pinhole image 3a'' and the ring slit image 2', the eye to be examined E In the above-described embodiment, the scanning light beam is formed into a ring shape near the pupil, but if a partial aperture 2b as shown in FIG.
A diaphragm plate having a diaphragm plate may be arranged.

In this embodiment, instead of the fixed diaphragm 7 and variable position diaphragm plate 8, a cylindrical diaphragm that shares both may be provided.Furthermore, in place of the fixed diaphragm 7, a separate variable diaphragm may be provided to extract a predetermined luminous flux. A diaphragm may be used at any position before or after the projection lens 9.

FIG. 8 shows a second embodiment of the present invention, in which an image is obtained by scanning an area using a spot image projected onto the fundus 1j. In FIG. 8, the same reference numerals as in FIG. The angle of view projected onto the fundus Ef is twice the angle of view of the perforated mirror 5, so the direction of the angle of view of the projected light beam and the direction of the aperture 8a of the variable position aperture plate 8 can be In order to match, the aperture 8a must be swung by half the swing angle of the perforated mirror 5. Further, the reflected light flux from the fundus Ef, which is emitted from the fundus Ef and passes through the aperture 8a of the position variable diaphragm plate 8, is reflected by the imaging means lO.
image information can be obtained from the coordinates and photoelectric output at that point.

FIG. 9 shows a specific example thereof, in which the perforated mirror 5 is provided with an arm 11 extending radially from the center O of the hole, and at the tip thereof a hemispherical body 12 having the center 0 as the center of its spherical surface. is installed. The first ball 13 in contact with this hemispherical body 12 and the second pole 14 in contact with it are connected to the respective support members 13a, 13b and 14a, 14.
It is held by b. Then, a hemispherical variable-position aperture diaphragm plate 8 with the center 0 as the center of its spherical surface is attached to the second
It is held by a support member 15 in contact with the pole 14. Now, change the radius of the first ball 13 to the second pole 14.
is twice the radius of
If it is set in advance on the photographing optical axis, the aperture diaphragm plate 8 will be fixed at an appropriate position according to the tilting of the perforated mirror 5.

FIG. 10 shows another example of the scanning method, and the symbols are the first
According to the diagram. In this embodiment, the pinhole 3a of the pinhole plate 3 is made to swing instead of the perforated mirror 5. That is, the light source 1, the ring slit plate 2, and the pinhole plate 3 are integrated, and are vibrated vertically and horizontally around the ring slit plate 2, which is arranged optically approximately conjugate with the hole of the perforated mirror 5. ing. Furthermore, in response to the change in the angle of view of the fundus Ef caused by this vibration, the aperture diaphragm plate 8 is interlocked within its plane so that the photographing light beam passes through the aperture 8a of the variable aperture diaphragm plate 8. There is.

In each of these embodiments, a case has been described in which a node projected onto the fundus Ef is formed with a pinhole light source and is waved or scanned with a mirror; A monitor may be used, and an acousto-optic device or the like may also be used for the scanning itself. Furthermore, for the aperture diaphragm, a member that can form a photoelectrically transparent part, such as a liquid crystal plate, may be used.Also, in the above embodiment, the illumination light flux side was formed in a ring shape near the pupil position, but this method It is also possible to completely reverse this and replace the light receiving side and the light emitting side. In addition, the light receiving means may be a total light receiving means such as a photomulti placed approximately conjugate with the pupil of the subject @E, or a light receiving means capable of measuring the coordinate position such as an area type COD may be provided with the fundus Ef of the subject's eye E. In some cases, it is provided approximately conjugately. Furthermore, as means for projecting and scanning one point, various types of light deflecting means may be provided approximately conjugate with the pupil of the eye E to be examined.

[Effects of the Invention] As explained above, the fundus scanning device according to the present invention is a fundus observation device that scans the fundus with a bright spot to obtain fundus information, and converts harmful scattered light in the anterior segment of the scanning light beam into an effective photographing light beam. Since it can be completely separated from the passband, there is no need to shield the imaging section other than the spot light portion, and a clear image can be obtained over a wide field of view.

[Brief explanation of the drawing]

The drawings show an embodiment of the fundus scanning device according to the present invention.
The figure shows the configuration of the first embodiment, Figure 2 is a front view of the ring slit plate, Figure 3 is a front view of the pinhole plate, Figure 4 is a front view of the aperture plate, and Figure 5 is the fundus of the eye. FIG. 6 is an explanatory diagram of the state of light beam scanning in and out of the eye to be examined. FIG. 7 is a front view of the aperture plate. FIG. 8 is a configuration diagram of the second embodiment. FIG. 9 is a configuration diagram of the interlocking mechanism of the mirror and aperture stop, 1st
FIG. 0 is a configuration diagram of the third embodiment. Symbol l is a light source, 2 is a ring slit plate, 3 is a pinhole plate, 4 is a relay lens, 5 is a perforated mirror, 6 is an objective lens, 7 is an aperture diaphragm, 8 is a variable aperture diaphragm plate, 9 is a projection lens , 10 is a light receiving element, and 10' is an imaging means.

Claims (1)

[Claims] 1. A means for projecting and scanning a bright spot toward the fundus of the eye to be examined;
The light-receiving means receives the reflected light flux from the fundus of the bright spot, and the variable-position light flux diaphragm guides the light flux corresponding to the angle of view from the fundus according to a change in the angle of view of the projection of the bright spot onto the fundus. A fundus scanning device characterized by: 2. The fundus scanning device according to claim 1, wherein the variable position light flux diaphragm is used together with a fixed diaphragm that is substantially conjugate with the anterior segment of the eye. 3. The fundus scanning device according to claim 1, wherein the means for projecting and scanning the bright spot scans a bright spot provided at a position optically substantially conjugate with the fundus of the eye to be examined. 4. The fundus scanning device according to claim 1, wherein the means for projecting and scanning the bright spot is a light deflecting means provided at a position optically substantially conjugate with the pupil of the eye to be examined. 5. The fundus scanning device according to claim 1, wherein the light receiving means is a total light amount receiving means, and is arranged to be optically substantially conjugate with the pupil of the eye to be examined. 6. The fundus scanning device according to claim 1, wherein the light receiving means is a light receiving means capable of measuring a coordinate position, and is arranged to be optically substantially conjugate with the fundus of the eye to be examined.