JPH1080400A - Illuminating apparatus for retinal camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a bright eyeground image without introducing upsizing of an electric source even during photographing of high magnifying power and to obtain the bright eyeground image by a small electric power during photographing of low magnifying power. SOLUTION: A ring-shaped luminous flux forming means provided with an incident end 22A positioned in the neighborhood of a light source image, a ring-shaped emitting end 22D, a conical outside reflecting face 22B and a conical inside reflecting face 22C and for reflecting an illuminating light incident in the incident end 22A on the outside reflecting face 22B and on the inside reflecting face 22C and guiding it to the emitting end and emitting a ring-shaped luminous flux from the emitting end, is installed. The ring-shaped luminous flux forms a ring-shaped illuminating region in the neighborhood of the pupil of an eye to be examined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device for a fundus camera, and more particularly to an illuminating device for illuminating the fundus of an eye to be examined for a fundus camera for photographing the fundus of the eye via an objective lens. .

[0002]

2. Description of the Related Art Conventionally, in an ophthalmologic apparatus such as a fundus camera, ring illumination has been used to avoid reflection from the cornea of an eye to be examined. In ring illumination, usually, a ring slit is arranged at a position substantially conjugate with the pupil of the eye to be inspected, and of the light flux from the light source, the light flux passing through the ring-shaped opening of the ring slit is imaged near the pupil of the eye to be examined. Lighting. Here, the ring slit is arranged at a position almost conjugate with the light source via the condenser lens, but the shape of the light source such as the observation lamp light source and the strobe light source for photography is not ring-shaped (ring-shaped). Normal. As a result, the brightest central light flux of the illumination light flux from the light source is blocked by the light blocking portion of the ring slit,
The illumination light could not be used effectively.

On the other hand, since the reflectance of the fundus of the eye to be inspected is extremely small, the fundus image formed becomes dark when the magnification is increased, and there is a disadvantage that high magnification photographing cannot be performed. Further, if the output intensity of the light source is simply increased in order to obtain a bright fundus image, there may be a disadvantage that the power supply unit becomes large and heat is generated by the light source.
Therefore, the present applicant has proposed an illuminating device for a fundus camera to solve the above-mentioned inconvenience in Japanese Patent Application Laid-Open No. 56-163629. In the conventional illumination device for a fundus camera proposed in this publication, an optical fiber having an incident surface and an annular exit surface similar in shape to the shape of the light source is arranged between the condenser lens and the relay lens. I have. Then, a light source image is formed on the entrance surface of the optical fiber via a condenser lens, and an orbicular luminous flux from the exit surface of the optical fiber is supplied to the subject's eye.

[0004]

However, in the above-described conventional retinal camera illumination device, an optical fiber is formed by bundling thin fibers one by one. For this reason, a light amount loss due to the gap between the fibers and a light amount loss due to the multiple reflection in the fiber occur, and there is a disadvantage that sufficiently bright illumination light cannot be obtained. Furthermore, optical fibers cannot be bent at large bending angles due to their structure. As a result, in the conventional illumination apparatus for a fundus camera, if an optical fiber is arranged in the optical path of the illumination system, there is a disadvantage that the illumination system is inevitably increased in size.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and enables a bright fundus image to be obtained without increasing the size of a power supply even during high-magnification photographing, and requires less power supply during low-magnification photographing. An object of the present invention is to provide a small illumination device for a fundus camera capable of obtaining a bright fundus image.

[0006]

According to the present invention, there is provided a fundus camera for illuminating a fundus of an eye to be examined for photographing the fundus of the eye through an objective lens. In a lighting device, a light source for supplying illumination light, a condensing optical system for condensing illumination light from the light source to form a light source image, and positioning near a position where the light source image is formed The incident end, a ring-shaped exit end, an outer reflective surface formed between an outer peripheral portion of the exit end and an outer peripheral portion of the incident end, and an inner peripheral portion of the exit end. An inner reflection surface formed inside the outer reflection surface, wherein the illumination light incident on the incident end is reflected by the outer reflection surface and the inner reflection surface to be guided to the emission end, and the emission end is Ring light beam type for emitting a ring light beam from And a ring-shaped light beam emitted from an emission end of the ring-shaped light beam forming means forms a ring-shaped illumination area near the pupil of the eye to be examined via the objective lens. And a lighting device for a fundus camera.

According to a preferred aspect of the present invention, the angle between the outer reflective surface and the optical axis is equal to or larger than the angle between the inner reflective surface and the optical axis. The ring-shaped light beam forming means may have a hollow space between the outer reflecting surface and the inner reflecting surface, or may have a solid structure. It is preferable that the ring-shaped light beam forming means is configured to be exchangeable with another ring-shaped light beam forming means having a different diameter at the exit end.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a ring-shaped exit end positioned substantially conjugate with a light source image and having a ring-shaped exit end positioned substantially conjugate with a pupil of an eye to be examined. A light beam forming means is provided. In addition, a conical outer reflective surface is formed between the outer peripheral portion of the ring-shaped exit end and the outer peripheral portion of the circular incident end, and the inside of the outer reflective surface is connected to the inner peripheral portion of the exit end. Is formed with a conical inner reflective surface. Therefore, the illumination light incident on the incident end of the ring-shaped light beam forming means is repeatedly reflected on the outer reflecting surface and the inner reflecting surface, and then emitted from the emitting end as a ring-shaped light beam. The ring-shaped light beam emitted from the emission end of the ring-shaped light beam forming means forms a ring-shaped illumination area near the pupil of the subject's eye via an objective lens shared by the illumination system and the observation and imaging system.

That is, in the present invention, the light from the formed light source image is taken into the incident end of the ring-shaped light beam forming means without substantial loss. The ring-shaped light beam forming means includes:
The light captured at the incident end is guided to the emission end without substantial loss, and emitted as a ring-shaped light beam. The emitted ring-shaped light beam forms a ring-shaped illumination area near the pupil of the eye to be inspected, and as a result, the fundus of the eye to be inspected is widely illuminated. As described above, in the present invention, the light from the light source can be effectively used without substantial loss, and the fundus can be illuminated with sufficiently bright illumination light. As a result, a bright fundus image can be obtained without increasing the size of the power supply even during high-magnification shooting, and a bright fundus image can be obtained with less power supply during low-magnification shooting. Further, since the ring-shaped light beam forming means of the present invention can be made small in structure, unlike the conventional technique using an optical fiber whose bending angle is limited, the whole device can be made compact.

The angle between the outer reflecting surface and the optical axis must be large so that the light taken into the incident end of the ring-shaped light beam forming means is guided to the exit end without returning to the incident end. It is necessary that the angle be equal to or larger than the angle between the inner reflecting surface and the optical axis. Further, specifically, the ring-shaped light beam forming means may have a hollow space between the outer reflecting surface and the inner reflecting surface, or may have a solid structure.
Further, in order to change the diameter of the ring-shaped light beam formed at the exit end according to the size of the pupil of the eye to be inspected, another ring-shaped light beam having a different diameter at the exit end is used. It is preferable to configure it so that it can be replaced with the forming means.

An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram illustrating a configuration of an illumination device for a fundus camera according to an embodiment of the present invention, together with an observation system and an imaging system of the fundus camera. FIG. 2 is a diagram showing a configuration of the conical reflection member 22 of FIG.
7A illustrates the shape of the emission end 22D, and FIG. 7C illustrates the cross-sectional shape of the conical reflecting member 22 and the path of the light beam.

The apparatus shown in FIG. 1 includes an observation light source 19 such as a lamp light source. The observation illumination light emitted from the observation light source 19 is condensed via the condenser lens 18 at the position of the imaging light source 17 which is substantially conjugate with the observation light source 19. The photographing light source 17 is, for example, a strobe light source. As described above, the imaging illumination light from the imaging light source 17 and the observation illumination light from the observation light source 19 are equivalent, and are treated as illumination light without distinction in the subsequent illumination system.

The illumination light emitted from the photographing light source 17 or the observation light source 19 passes through the first relay lens 16 and the reflection mirror 15 and forms a light source image. Near the position where the light source image is formed, the entrance end 22 of the conical reflection member 22 is located.
A is positioned. That is, the observation light source 19, the imaging light source 17, and the incident end 22A of the conical reflection member 22 are substantially conjugate with each other. Therefore, the light source image of the observation light source 19 or the light source image of the imaging light source 17 is formed on the incident end 22A of the conical reflection member 22. In addition, as shown in FIG.
Is preferably circular and has a size equal to or larger than the size of the light source image in order to avoid loss of light amount. On the other hand, FIG.
As shown in (b), the emission end 22 of the conical reflection member 22
D is configured in a ring shape.

As shown in FIG. 2C, a conical outer reflection surface 22B is formed between the outer periphery of the ring-shaped exit end 22D and the outer periphery of the circular entrance end 22A. ing. Further, a conical inner reflecting surface 22C is formed inside the outer reflecting surface 22B so as to be connected to the inner peripheral portion of the ring-shaped emitting end 22D. And the outer reflective surface 2
The space between 2B and the inner reflection surface 22C is formed hollow. That is, the conical reflection member 22 is
It is a hollow member including a conical outer cylindrical portion (not shown) formed with B and a conical inner cylindrical portion (not shown) formed with the inner reflection surface 22C. The formation of the reflection surfaces inside the outer cylindrical portion and outside the inner cylindrical portion is performed by, for example, aluminum evaporation.

Therefore, as shown in FIG. 2 (c), the light beam incident on the incident end 22A is reflected by the inner reflecting surface 22C and the outer reflecting surface 22B, and is emitted from the ring-shaped emitting end 22D. In this manner, the illumination light incident on the incident end 22A is effectively used without substantial loss, and
D can be emitted as a ring-shaped light beam. The ring-shaped light beam emitted from the emission end 22D of the conical reflection member 22 forms an image near the perforated mirror 12 via the second relay lens 13. That is, the exit end 22D of the conical reflection member 22 and the perforated mirror 12 have a substantially conjugate relationship. At this time, the image of the emission end 22D of the conical reflection member 22 is formed on the perforated mirror 12 to be larger than the diameter of the hole.

The light reflected by the perforated mirror 12 forms a ring-shaped illumination area via the objective lens 1 at the pupil position 20 of the subject's eye positioned almost conjugate with the perforated mirror 12. That is, the emission end 22 of the conical reflection member 22
D, the perforated mirror 12, and the pupil position 20 of the eye to be examined have a substantially conjugate relationship. Thus, the illumination light that has entered the subject's eye illuminates the fundus of the subject's eye widely. In an actual fundus camera, the conical reflection member 22 and the second relay lens 1
A light-shielding plate for avoiding reflection from the lens of the subject's eye is disposed between the light-shielding plate and the light-shielding plate 3, but this light-shielding plate is not shown because it has no relation to the essence of the present invention.

The reflected light from the illuminated fundus of the eye to be examined is
An image is formed once through the objective lens 1 shared by the observation imaging system and the illumination system, and then passes through the hole of the perforated mirror 12.
As described above, the illumination light from the observation light source 19 or the imaging light source 17 and the reflected light from the fundus of the subject's eye are separated by the function of the perforated mirror 12. The reflected light that has passed through the hole of the perforated mirror 12 forms a fundus image on the light receiving surface 5 of the first imaging system via the imaging relay lens 2 and the variable power lens 3.

The mirrors 4 and 8 are switching reflecting members for switching the optical path. Therefore, when the switching mirror 4 is positioned on the optical path as shown in FIG. 1, light from the fundus of the eye to be inspected is reflected by the switching mirror 4 and guided to the observation system, and the reflection mirror 6 and the eyepiece are reflected. Lens 7
Through the eye of the examiner. Thus, the examiner can observe the fundus image of the eye to be examined by positioning the pupil at the eye point position 21 of the eyepiece 7. On the other hand, when the switching mirror 4 is retracted out of the optical path and another switching mirror 8 is positioned on the optical path, light from the fundus of the eye to be inspected is reflected by the switching mirror 8, and is reflected by the imaging lens 9 and the reflection lens. Light receiving surface 11 of the second imaging system via mirror 10
A fundus image is formed on top.

As described above, in a conventional illumination device for a fundus camera using a ring slit, a light source image is formed on the ring slit. Therefore, only a part of the illumination light forming the light source image can pass through the ring-shaped opening of the ring slit. Also, in the light source image formed on the ring slit, the center is usually brighter than the periphery. Therefore, in the related art in which the fundus is illuminated only by light from the periphery of the light source image formed on the ring slit,
The illumination light from the light source cannot be used effectively.

On the other hand, in this embodiment, the light from the light source image is substantially not lost, and
2A, the captured light is guided to the emission end 22D without substantial loss, and can be emitted as a ring-shaped light beam. Therefore, in this embodiment, the light from the light source can be effectively used without substantial loss, and the fundus can be illuminated with sufficiently bright illumination light. As a result, a bright fundus image can be obtained without increasing the size of the power supply even during high-magnification shooting, and a bright fundus image can be obtained with less power supply during low-magnification shooting. Further, since the conical reflection member 22 of the present embodiment can be made small in structure, unlike the conventional technology using an optical fiber whose bending angle is limited,
The whole device can be made compact.

FIG. 3 is a view for explaining the relationship between the apex angle of the conical outer reflection surface 22B and the apex angle of the conical inner reflection surface 22C in the conical reflection member 22 of FIG. As described above, the conical reflection member 22 is a hollow member having a hollow space between the outer reflection surface 22B and the inner reflection surface 22C. The angle (vertical angle) between the inner reflecting surface 22C and the optical axis AX is α, and the angle between the outer reflecting surface 22B and the optical axis AX is β.

Therefore, in FIG. 3, the light ray R incident at a certain angle with respect to the optical axis AX is reflected at the point P1 on the inner reflecting surface 22C and is incident on the point P2 on the outer reflecting surface 22B. At this time, the angle between the ray N and the normal line N1 of the inner reflection surface 22C at the point P1 is defined as θ1.

The normal line N of the outer reflecting surface 22B at the point P2
The angle .theta.2 between the light ray 2 and the light ray R is expressed by the following equation (1).

[Equation 1] θ2 = θ1− (α−β) (1)

Therefore, as shown in FIG. 3, when the angle α is larger than the angle β, the reflection angle θ 2 at the outer reflecting surface 22B becomes
It becomes smaller than the reflection angle θ1 at C. As a result, the light beam R that has been repeatedly reflected inside the hollow of the conical reflection member 22 is not emitted from the emission end 22D, and
It goes back to 2A. Therefore, the magnitude of the vertex angle β of the outer reflecting surface 22B of the conical reflecting member 22 is
It is necessary that the angle is equal to or larger than the apex angle α of the inner reflection surface 22C.

In the above embodiment, the outer reflecting surface 22
The example of the conical reflection member 22 in which the space between B and the inner reflection surface 22C is hollow is shown. However, the outer reflecting surface and the inner reflecting surface may be formed on a single member made of glass or resin, respectively, so that the space between the outer reflecting surface and the inner reflecting surface may be solid.

FIG. 4 is a diagram showing a configuration of a modification of the embodiment of FIG. The modification of FIG. 4 has the same configuration as that of the embodiment of FIG. 1, but differs from the embodiment of FIG. 1 only in that the conical reflection member 22 is configured to be exchangeable with another conical reflection member 23. I do. Accordingly, in FIG. 4, elements having the same functions as those of the embodiment of FIG. 1 are denoted by the same reference numerals as in FIG. In the modified example of FIG. 4, a plurality of conical reflecting members having different diameters of the ring-shaped exit end are prepared, and the conical reflecting member can be appropriately selected according to the size of the pupil of the eye to be examined. As a result, optimal ring illumination can be performed according to the size of the pupil of the eye to be inspected.

[0027]

As described above, the illumination apparatus for a fundus camera of the present invention can illuminate the fundus with sufficiently bright illumination light by effectively utilizing the light from the light source image without substantial loss. As a result, a bright fundus image can be obtained without increasing the size of the power supply even during high-magnification shooting, and a bright fundus image can be obtained with less power supply during low-magnification shooting. Further, since the ring-shaped light beam forming means of the present invention can be made small in structure, unlike the conventional technique using an optical fiber whose bending angle is limited, the whole device can be made compact.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an illumination device for a fundus camera according to an embodiment of the present invention, together with an observation system and a photographing system of the fundus camera.

2A and 2B are diagrams showing a configuration of a conical reflection member 22 in FIG. 1, wherein FIG. 2A shows the shape of an incident end 22A, FIG. 2B shows the shape of an exit end 22D, and FIG. The cross-sectional shape of the member 22 and the path of light rays are shown.

1. FIG. 3 is a plan view of the conical reflection member 22 shown in FIG.
It is a figure explaining the relationship with 2C of apex angles.

FIG. 4 is a diagram showing a configuration of a modification of the embodiment of FIG. 1;

[Explanation of symbols]

 Reference Signs List 1 objective lens 2 photographing relay lens 3 variable power lens 4, 8 switching mirror 5, 11 light receiving surface 6, 10, 15 reflection mirror 7 eyepiece 9 imaging lens 12 perforated mirror 13 second relay lens 16 first Relay lens 17 light source for photography 19 light source for observation 20 pupil position 21 eye point position 22, 23 conical reflection member

Claims (5)

[Claims] 1. A fundus camera illumination device that illuminates the fundus of an eye to be examined for a fundus camera that photographs the fundus of the eye to be examined via an objective lens, comprising: a light source for supplying illumination light; A condensing optical system for condensing the illumination light to form a light source image, an incident end positioned near a position where the light source image is formed, a ring-shaped exit end, An outer reflective surface formed between an outer peripheral portion and an outer peripheral portion of the incident end; and an inner reflective surface formed inside the outer reflective surface so as to be connected to the inner peripheral portion of the emission end. A ring-shaped light beam forming means for reflecting illumination light incident on the incident end by the outer reflecting surface and the inner reflecting surface to the emission end, and emitting a ring-shaped light beam from the emission end. Emitted from the emission end of the ring-shaped light beam forming means A ring-shaped light flux, the via objective lens, the illumination device for a fundus camera and forming a ring-like illumination area in the vicinity of the pupil of the eye. 2. The fundus camera according to claim 1, wherein an angle formed between the outer reflecting surface and the optical axis is equal to or larger than an angle formed between the inner reflecting surface and the optical axis. Lighting equipment. 3. The illuminating device for a fundus camera according to claim 1, wherein the ring-shaped light beam forming means has a hollow space between the outer reflecting surface and the inner reflecting surface. . 4. The illuminating device for a fundus camera according to claim 1, wherein the ring-shaped light beam forming means has a solid structure between the outer reflecting surface and the inner reflecting surface. . 5. The apparatus according to claim 1, wherein the ring-shaped light beam forming means is configured to be exchangeable with another ring-shaped light beam forming means having a different diameter at the exit end. A lighting device for a fundus camera according to the above.