JPH11347002A - Fundus imaging device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To easily clean dirt on an objective optical system. SOLUTION: The center of curvature of the surface of a concave filter 7 whose both surfaces have the same curvature is set near the pupil P, and the eye E to be examined is provided.
At the conjugate position of the ring slit 4. Accordingly, the reflected light of the illumination light from the surface of the filter 7 forms an image of the same size as the ring slit image near the perforated mirror 6 and returns to the illumination optical path O1. . When the filter 7 becomes dirty, the filter 7 can be removed and easily wiped off. At this time, since both surfaces of the filter 7 have almost the same curvature and little power, the mounting accuracy when attaching and detaching does not affect the image quality. .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus photographing apparatus used for photographing a fundus image in an ophthalmic hospital.

[0002]

2. Description of the Related Art In a conventional fundus photographing apparatus, a subject is seated in front of the apparatus and a face is fixed at a position where the subject's eye looks into an objective lens to photograph a fundus image.

[0003]

However, in the above-described conventional fundus photographing apparatus, the subject's tears and the like tend to adhere to the front surface of the objective lens, and the dirt easily occurs. Since the image passes through, the image quality of the fundus image deteriorates due to the contamination. Therefore, the examiner must check the state of the objective lens every time the measurement is performed, and perform a complicated operation of wiping off dirt, and this cleaning operation takes time.

An object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a fundus photographing apparatus that can easily clean dirt on an objective optical system.

[0005]

A fundus photographing apparatus according to the present invention for achieving the above object is a fundus photographing apparatus for separating illumination light and photographing light behind an objective optical system. And a filter whose front and back surfaces have substantially the same curvature is detachably provided in front of the objective optical system.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiment. FIG. 1 shows a configuration diagram of a fundus photographing apparatus according to the first embodiment, in which an incandescent lamp light source for observation 1, a condenser lens 2, a strobe light source 3 for photographing, and a pupil P of an eye E to be examined are arranged on an illumination optical path O1. A conjugate ring slit 4, a lens 5, and a perforated mirror 6 are sequentially arranged.
Is designed to form an image of the ring slit 4 near the perforated mirror 6.

On the observation / photographing optical path O2, a filter 7 from the eye E side, an objective lens 8 for forming an image of the pupil P of the eye E near the perforated mirror 6, a perforated mirror 6, and a pupil P are substantially formed. A conjugate photographing aperture 9, a photographing lens 10, and an image medium 11 which is a film or an image sensor are sequentially arranged.

The filter 7 is a cover glass for preventing the objective lens 8 from being stained, and has a concave surface having substantially the same curvature on both sides, and is fixed by inserting the holding ring 13 into the lens barrel 12 holding the objective lens 8. It is easily detachable.

The center of curvature of the surface of the filter 7 is near the pupil P and coincides with the conjugate position of the ring slit 4 in the eye E to be examined. For this reason, the reflected light of the illumination light from the surface of the filter 7 forms an image of the same size as the ring slit image near the perforated mirror 6 and returns to the illumination optical path O1. Has no effect. Filter 7
When is dirty, the filter 7 can be removed and easily wiped off. At this time, since both surfaces of the filter 7 have almost the same curvature and little power, the mounting accuracy at the time of attachment / detachment does not affect the image quality.

In this embodiment, the radius of curvature of the filter 7 is set to the distance to the pupil P. However, any curvature may be used as long as the reflected light does not enter the photographic stop 9.

FIG. 2 is a structural view of a main part of the second embodiment. A filter 7, an objective lens 8, and a photographing stop 9 are arranged on an optical path O3, and the filter 7 is inclined with respect to the optical path O2. It is attached. Other configurations are the same as those of the first embodiment.

The radius of curvature of the filter 7 is slightly larger than the distance of the ring light beam R to the image R 'by the objective lens, and the image R "due to the reflection of the ring light beam R from the filter 7 is slightly larger than the ring light beam R. Reflected light L
Does not enter the shooting aperture 9. Further, in this embodiment, since the illumination light does not enter the filter 7 perpendicularly, the filter 7 is not contaminated.

[0013]

As described above, in the fundus photographing apparatus according to the present invention, a filter having a center of curvature on the side of the eye to be examined and having substantially the same curvature on the front and back surfaces is provided detachably in front of the objective optical system. Accordingly, the dirt on the objective optical system can be easily cleaned, and a clear fundus image can always be taken.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a fundus imaging apparatus according to a first embodiment.

FIG. 2 is a configuration diagram of a main part of a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Incandescent lamp light source 3 Strobe light source 4 Ring slit 6 Perforated mirror 7 Filter 8 Objective lens 9 Shooting aperture 11 Image medium 12 Lens barrel

Claims (2)

[Claims] 1. A fundus photographing apparatus that separates illumination light and photographing light behind an objective optical system, wherein a filter having a center of curvature on the side of the eye to be examined and having substantially the same curvature on the front and back surfaces is attached and detached in front of the objective optical system. A fundus photographing device, which is provided freely. 2. The fundus imaging apparatus according to claim 1, wherein the center of curvature of the filter is near a pupil of the eye to be examined.