JPH0471526A - Fundus camera - Google Patents

Abstract

PURPOSE:To satisfactorily photograph an eye with a small pupil diameter and continuously photograph it even when photographing fails by providing a means switching the aperture of an optical system in response to the pupil diameter of the checked eye and a means switching the photographing mode from the film recording mode to the electronic image recording mode. CONSTITUTION:When an aperture switching means 25 is operated in response to the pupil diameter of an eye to be checked 12, an illumination system aperture 13 or a photographic system aperture 24 in the optical path of an optical system is switched, the signal output of the aperture switching means 25 is inputted to a recording mode switching means 27, and the switching means controls a luminescence control means 28 to perform film recording or electronic image recording based on the signal output. Film recording can be satisfactorily performed even when the light quantity is insufficient, if no stroboscopic luminescence is required for photographing the checked eye 12 with a small pupil diameter, luminescence may be prohibited in conjunction with the aperture switching, if stroboscopic luminescence is required, luminescence may be used. Even when the photographing of film recording fails and the pupil is shrunk by stroboscopic luminescence, the checked eye 12 can be continuously photographed.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention enables good imaging of the fundus even in the case of an eye to be examined with a small pupil diameter in which good film recording cannot be performed due to insufficient exposure, etc. Regarding the fundus camera.

(Prior art) Conventional fundus cameras have one or more of the following: an illumination diaphragm, a photographic diaphragm, and a photographic light amount, so that the amount of fog on the photographic film remains constant as the magnification changes. Some systems use a combination of these methods to adjust the exposure amount. Furthermore, there is also a ring slit illumination in which the light shielding area of the light shielding part is changed depending on the pupil diameter of the eye to be examined.

For example, Japanese Patent Publication No. 61-44499 discloses that the amount of illumination light can be increased by changing the light shielding object that is conjugate with the crystalline lens of the subject's eye (move it in the optical axis direction or change its dimensions without moving it) according to the magnification change. It is configured to be adjusted.

Further, Japanese Patent Publication No. 62-54497 has a configuration in which the cross-sectional area of a ring slit conjugate with the pupil of the eye to be examined is changed in accordance with the change in magnification to adjust the amount of light.

(Problems to be solved by the invention) However, conventional fundus cameras have the following problems: ■ Ease of alignment, ■ Impact on the eye to be examined due to increased illumination light intensity (in particular, consideration should be given to minimizing glare), ■ Equipment The minimum pupil diameter for good film recording was determined to be 4 mm, after comprehensively determining the size of the pupil and the like.

Therefore, when the pupil diameter is 4 mm or less, there is a problem that a clear fundus image cannot be obtained due to insufficient light quantity, etc.

Furthermore, when the amount of illumination light is increased in order to resolve the insufficient amount of light, there is also the problem that flare and the like occur in photographs.

Furthermore, with a non-mydriatic fundus camera, if the subject's blinking cape is present when the strobe is emitted, the image will fail; However, there is the inconvenience of having to wait for a long time until the subject's eye naturally dilates, even though the subject wants to take another picture. Even in such a case, it is desirable to be able to take pictures immediately.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to enable good imaging even if the pupil diameter of the eye to be examined is smaller than a predetermined value that is considered to be the limit that would cause problems when recording on film. To provide a fundus camera capable of continuously photographing without waiting for a long time even if the camera fails.

(Means for Solving the Problems) In order to achieve the above object, the fundus camera according to the present invention includes an aperture switching means for switching the aperture in the optical path of the optical system according to the pupil diameter of the eye to be examined; The present invention is characterized by comprising recording mode switching means for switching the mode from film recording mode to electronic video recording mode.

(Function) According to the present invention, when the aperture switching means is operated in accordance with the pupil diameter of the eye to be examined, the aperture in the optical path of the optical system is switched. That is, since the aperture of the illumination system or the photographing system is switched and the film recording mode is switched to the electronic video recording mode, good recording can be performed even if the amount of light is insufficient for film recording. In addition, if strobe light emission is not necessary when photographing an eye to be examined with a small pupil diameter, flash emission may be prohibited in conjunction with switching the aperture.
If strobe light emission is necessary, it may be emitted.Furthermore, even if the photographing for film recording fails and the pupils are constricted due to strobe light emission, photography can be continued.

(Example) Hereinafter, an example of the ophthalmologic apparatus according to the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a first embodiment of the present invention, in which 1 is a concave mirror, 2 is a halogen lamp as an observation light source, 3 is a relay lens, 4 is a xenon lamp as a photographing light source, and 5 is a xenon lamp as a photographing light source. In the condenser lens, a concave mirror 1, a halogen lamp 2, a relay lens 3, a xenon lamp 4, and a condenser lens 5 are provided in this order on an optical axis 6.

These optical members 1 to 5 include a mirror 7, a projection lens 8,
Together with the perforated mirror 9 and the objective lens 10, it constitutes an illumination optical system. An eye 12 to be examined faces the objective lens 10 . An illumination diaphragm 13 is arranged between the condenser lens 5 and the mirror 7. This illumination aperture 13 is the aperture 13
a, 13b. The aperture 13a is conjugate with the iris of the eye 12 to be examined with respect to the projection lens 8.

The aperture 13b is conjugate with the cornea of the eye 12 to be examined with respect to the projection lens 8. On the other hand, on the optical axis 11 of the objective lens 10,
An objective lens 10, a perforated mirror 9, a focusing lens 14, an imaging lens 15, a quick return mirror 16, and a film 17 are provided in order from the one closest to the eye 12 to be examined. A quick return mirror 19 and an imaging collector 20 are provided on the reflection optical axis 18 of the quick return mirror 16. An eyepiece scale 22 and an eyepiece lens 23 are provided on the reflection optical axis 21 of the quick return mirror 19. The examiner observes the fundus of the subject's eye 12 projected on the eyepiece scale 22 through the eyepiece lens 23. A photographic aperture 24 is arranged between the perforated mirror 9 and the focusing lens 14.

Two types of illumination diaphragm 13 and photographic diaphragm 24 are provided, each corresponding to the pupil diameter. The illumination diaphragm 13 consists of a diaphragm 13' that is inserted into the optical path when the pupil diameter is such that it does not interfere with film recording, and a diaphragm 13# that is inserted into the optical path when the pupil diameter is such that it does not interfere with film recording. ing. Similarly, the photographic aperture 24 has two types: a diaphragm 24' that is inserted into the optical path when the pupil diameter is such that it does not interfere with film recording, and a diaphragm 24'' that is inserted into the optical path when the pupil diameter is such that it does not interfere with film recording. The illumination diaphragm 13 and the photographic diaphragm 24 are inserted into the optical path by operating the diaphragm switching means 25.The diaphragm switching means 25 is of a rotary type, and the "O" position is set for film recording. This is selected when the pupil diameter does not cause any problems.
At the rQJ position, an illumination diaphragm 13' and a photographic diaphragm 24' are inserted into the optical path. Positions "1" to "3" are selected when the pupil diameter causes problems in film recording, and at the "1" position, the illumination diaphragm 13' is switched and the illumination diaphragm 13# is inserted into the optical path. "2"
At the position, the photographing aperture 24' is switched to the photographing aperture 24'.
'' is inserted into the optical path.

At the "3" position, both the illumination diaphragm 13' and the photographic diaphragm 24' are switched, and the illumination diaphragm 13# and the photographic diaphragm 24 are switched.
'' are respectively inserted into the optical path.

2 to 4 show a luminous flux 40 of illumination light and a luminous flux 41 of photographic light on the perforated mirror 9 based on switching of the illumination diaphragm 13 and photographing diaphragm 24 when each position of the diaphragm switching means 25 is selected. FIG. 2 is a diagram seen from the focusing lens 15 side. Figure 2 shows the case where the illumination diaphragm 13' and photography diaphragm 24' are inserted into the optical path, Figure 3 shows the case where the illumination diaphragm 13' and photography diaphragm 24' are inserted into the optical path, and Figure 4 shows the case where the illumination diaphragm 13' and photography diaphragm 24' are inserted into the optical path. Each figure shows the case where the photographing aperture 24'' is inserted into the optical path. In addition, 9a in the figure is a hole of the perforated mirror 9.

The examiner confirms the pupil diameter of the eye 12 to be examined, determines whether or not it is large enough to be recorded on film, and then operates the aperture switching means 25. A signal from the aperture switching means 25 is input to an aperture drive circuit 26. The aperture driving circuit 26 switches the aperture according to the selected position of the aperture switching means 25. The signal output from the aperture switching means 25 is input to the recording mode switching means 27. The recording mode switching means 27 controls the light emission control means 28 to perform film recording or electronic image recording based on the signal output. In the film recording mode, the quick return mirror 16 is moved out of the optical path when the photographing switch 28 is operated, and is automatically returned to the optical path after photographing is completed. When the quick return mirror 19 is in the electronic image recording mode, the optical path is also moved out of the way when the photographing switch 29 is operated, and the quick return mirror 19 is automatically returned to the optical path after photographing is completed. The light emission control means 28 causes the xenon lamp 4 to emit light in the film recording mode, and also drives the shutter drive circuit 30 almost simultaneously with the light emission of the xenon lamp 4. A shutter drive circuit 30 controls a shutter 31. On the other hand, in the electronic video recording mode, the light emission control means 28 causes the xenon lamp 4 to emit light when it is necessary to emit light by operating the photographing switch 29, and does not cause it to emit light when it is not necessary to emit light.

According to the fundus camera according to the present invention, even if the pupil diameter causes a problem in film recording, it can be photographed without any problem by switching the aperture.

FIG. 5 is a block diagram showing a second embodiment of the present invention, and the same components as those in the first embodiment are given only the reference numerals and redundant explanation will be omitted.

In this second embodiment, an objective lens 10 and a perforated mirror 9 are used.
A movable half mirror (or wavelength division mirror) between
32 are arranged. A relay lens 34 is arranged on the reflection optical axis 33. An image point F1 that is conjugate to the pupil of the eye 12 and the objective lens 10 is formed between the half mirror 32 and the relay lens 34 . The light-receiving surface of the image sensor 35 is disposed at a position where an image point F2 conjugate to the image point F1 and the relay lens 34 is formed.

The half mirror 32 is inserted into the optical path when the pupil diameter measurement switch 36 is operated. When the examiner observes the eye to be examined through the eyepiece lens 24 and operates the pupil diameter measurement switch 36, a pupil image is formed on the imaging device 35.

A pupil diameter determination circuit 37 is connected to the image sensor 35 , and the pupil diameter determination circuit 37 calculates the pupil diameter based on the imaging output of the image sensor 35 . This pupil diameter judgment circuit 37 is connected to the recording mode switching means 27, and the recording mode switching means 27 operates in accordance with the size of the measured pupil diameter.
Automatically select film recording mode or electronic video recording mode.

Although the embodiments have been described above, it is also possible to adopt a configuration in which the amount of illumination light from the xenon lamp 4 and the halogen lamp 2 is increased or decreased. With this configuration, it is possible to obtain a good electronic video recording image even when the aperture is switched in accordance with a small pupil diameter. Alternatively, a variable density ND filter may be provided between the perforated mirror 9 and the photographing aperture 24 to increase or decrease the amount of photographing light.

(Effects of the Invention) According to the fundus camera according to the present invention, even if the pupil diameter of the eye to be examined is smaller than the pupil diameter that allows good film recording, imaging can be performed without any problem. .

Further, even if the photographing fails, the photographing can be continued without waiting for a long time.

[Brief explanation of drawings]

1 to 4 are diagrams showing a first embodiment of the Wi-bottom camera according to the present invention, in which FIG. 1 is an optical diagram thereof, and FIGS. 2 to 4 are diagrams based on the operation of the aperture switching means. FIG. 5 is an optical diagram showing the second embodiment.

Claims (4)

[Claims] (1) It is characterized by having an aperture switching means for switching the aperture in the optical path of the optical system in accordance with the pupil diameter of the eye to be examined, and a recording mode switching means for switching the shooting mode from a film recording mode to an electronic image recording mode. Fundus camera. (2) The fundus camera according to claim 1, further comprising an illumination/photography light amount increasing/decreasing means for increasing/decreasing at least one of the illumination light amount and the photographing light amount. (3) The fundus camera according to claim 1, wherein imaging is performed in an electronic image recording mode when the pupil diameter of the eye to be examined is small. (4) comprising a measuring means for measuring the pupil diameter of the eye to be examined, and a determining means for determining whether the pupil diameter is below a predetermined value;
4. The aperture switching means is controlled so that an aperture corresponding to a small pupil is inserted into the optical path, and the recording mode switching means is controlled so as to switch to the electronic image recording mode. fundus camera.