JPS6012036A - Eyeground 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 frees the photographer from the trouble of inserting/removing filters necessary for alignment and focusing when performing fluorescence fundus photography, and at the same time This invention relates to a fundus camera that alleviates the pain experienced by people due to glare from fundus illumination light.

Fluorescent fundus photography measures the time when the fluorescent agent injected into the subject's veins reaches the intraocular circulation system, illuminates the fundus with blue light that has passed through an exciter filter, and measures the amount of blood in the blood vessels in the fundus. This is done by photographing the fluorescence emitted by the fluorescent agent through a barrier filter. In this case, it is necessary to insert an exciter filter having wavelength light transmittance characteristics shown in A in FIG. 1 into the illumination optical path, and a heliar filter with characteristics shown in FIG. 1 into the photographing optical path. Furthermore, alignment and focusing between the fundus and camera must be performed with the barrier filter removed. The reason for this is that when both the exciter filter and the barrier filter are inserted into the optical path, the fundus image seen through the fine material is very dark and difficult to focus.

In general, in fluorescence fundus photography, several dozen films are taken at intervals of seconds to record the emission of fluorescence from the fundus, during which time a barrier filter is inserted and removed for alignment and focusing with the fundus. This requires frequent repetition of operations. However, since the image of the fundus of the subject with the barrier filter removed from the imaging optical path is illuminated with blue light, the visibility of the fundus is poorer than with white light illumination during normal color imaging. . Furthermore, for the examinee, during the period of several dozen images being taken, the amount of light constantly entering the eye is several times that of the amount of light used to illuminate the fundus during color photography.
It will be very bright and painful.

The purpose of the present invention is to eliminate the above-mentioned troublesomeness of the photographer's filter operation, facilitate the alignment of the fundus and camera, and at the same time relieve the suffering of the subject from glare caused by the fundus illumination light. It is an object of the present invention to provide a fundus camera capable of photographing a fluorescent fundus, the gist of which is to provide a camera capable of photographing a fluorescent fundus, the camera having an operating means for simultaneously inserting and removing an exciter filter and a barrier filter into an illumination optical path and a photographing optical path; The present invention is characterized by having means for causing the photographing light source to emit light at any time after the exciter filter and barrier filter are inserted by the operating means.

The present invention will be explained in detail based on the embodiments shown in FIG. 2 and below.

Fig. 2 is a configuration diagram showing an example of the optical system of an ophthalmological camera, where ■ is an observation light source consisting of a tungsten lamp, etc., and the light emitted from this tungsten lamp l is
It enters a mirror 4 through a condenser lens 2a, a photographing light source 3 consisting of a xenon discharge tube, etc., and a condenser lens 2b, where it is deflected and sequentially passes through an exciter filter 5, a ring slit plate 6, and relay lenses 7a and 7b. It is designed to reach the perforated mirror 8. Note that 9 is a reflecting mirror placed behind the observation light source 1 to collect and reflect the light from this lamp. The light that enters the perforated mirror 8 from the above-mentioned illumination optical system is reflected by the perforated mirror 8 in the direction of the eye E to be examined, illuminates the fundus Ef of the examined eye E, passes through the original optical path, and then returns to the perforated mirror 8. and reaches the observation optical system. An objective lens 10 is arranged between the perforated mirror 8 and the subject's eye E, and the perforated mirror 8
Behind the lens, a barrier filter 11, a focusing lens 12, a photographic lens group 13, a movable mirror 14, a shutter 15, and a photographic film 16 are arranged in sequence along the optical axis. On the reflective side of the movable mirror 14, field lenses 17 are placed sequentially along the optical axis at positions conjugate with the photographic film 16.
, a mirror 18 for changing the optical path, and a finder 19 are arranged. Note that e is the examiner's □ eye.

The exciter filter 5 is inserted into and removed from the illumination optical path by driving a solenoid 20, and its operation is confirmed by a micro switch S5 shown in FIG. On the other hand, the barrier filter 11 is inserted into and removed from the photographing Φ observation optical path by driving the solenoid 21, and a contact point is formed.

Its operation is confirmed by a confirmation switch S2 consisting of microswitches S2a and S2b.

In this fundus camera, the illumination light source 1 and the photography light source 3 are substantially conjugate with respect to the condenser lens 2a, and the observation light source 1 is turned on during observation, and the photography light source 3 is turned on instantaneously during photography. The light source image is once formed near the ring slit plate 6 by another condenser lens 2b, and then an image of the annular opening of the ring slit plate 6 is formed near the perforated mirror 8 by relay lenses 7a and 7b. The illumination light is reflected and travels to the left. Then, after forming an image of the annular aperture near the crystalline lens El of the eye E to be examined using the objective lens 10, the fundus Ef is illuminated.

The reflected light from the fundus Ef travels to the right, and after being imaged by the crystalline lens El and the objective lens 10, it passes through the hole of the perforated mirror 8 and the photographic diaphragm (not shown), and is focused by the focusing lens 12 and photographic lens group 13. The image will be focused. During observation, the fundus image is placed on the movable mirror 14 at the solid line position.
the examiner's eye e through the finder 19.
observed by. When photographing, the movable mirror 14 rotates to the dotted position, and the fundus image is formed on the photographic film 16 via the opened shutter 15.

3, 4, and 5 are partial cross-sectional views of a gripping rod 30 through which a photographer operates this ophthalmological camera, and an operating button 31 is attached to the upper part of the gripping rod 30 so as to be movable up and down. Below the operation button 31 are three spring contacts Sa, Sb,
A switch S3 consisting of Sc is provided. Figure 3 shows the state in which the operation button 31 is not pressed, Figure 4 shows the first stroke (1/2 stroke), and Figure 5 shows the second stroke (full stroke) of the switch S3. It shows conduction and non-conduction states between spring contacts Sa, Sb, and Sc.

FIG. 6 is a block circuit diagram of the electric control circuit of this embodiment, and the same reference numerals as in FIGS. 2 to 5 indicate the same members. El is a power source for the photographing light source 3, and R2 is a power source for the driving solenoid 21 of the barrier filter 11. The switch S3 is a photographing switch located inside the aforementioned gripping rod 30;
Sla and Slb are changeover switches for switching between color photography and fluorescence photography, with firefly and light photography being performed on the eye side and color photography being performed on the mouth side.

S2a and S2b are the contacts of the switch S2 for checking the operation of the barrier filter 11, which operates the solenoid 20.21 in place of the switch S3, and is normally on the /\ side, but when making it act as the switch S3, it is turned on the second side. Moving. S4
is a contact of a relay 40 that operates simultaneously with the solenoids 20 and 21, and Sb is a switch for confirming the insertion of the exciter filter 5 mentioned above. 41 is a trigger circuit for lighting the photographing light source 3, R1 is a charging resistor, and C1 and C2 are discharging capacitors.

When performing fluorescence fundus photography, first turn on the selector switch Sla.
, Switch Slb to fluorescence photography on the A side. Next, the fluorescent agent is injected into the subject, and after a few seconds, when the fluorescent agent reaches the fundus of the eye, press the operation button 31 as shown in FIG. 4.
/If you press only 2 strokes, the switch S in Fig.
Contacts Sa and sb of No. 3 are electrically connected to operate the solenoids 20 and 21 and the relay 40.

Then, the exciter filter 5 and the barrier filter 11 are inserted into the optical path to short-circuit the relay contact S4. When the exciter filter 5 is inserted, the confirmation switch S5 becomes conductive, and both ends of the resistor R2 are short-circuited to increase the current flowing through the illumination light source 1 to increase the amount of fundus illumination light, thereby making it possible to observe a fluorescent image.

To take a picture, press the operation button 31 a further 1/2 stroke as shown in Fig. 5, and the contact s of the switch S3 will open.
b and Sc are electrically connected, and the signal lines L1 and R of the trigger circuit 41
2 are short-circuited and the photographing light source 3 emits light instantaneously. This completes one imaging session, but in fluorescent fundus imaging, it takes several dozen
Because it is necessary to take multiple film shots, the fundus E should be taken frequently.
It is necessary to correct the alignment with f and the defocus. When the exciter filter 5 and the barrier filter 11 are inserted, the amount of light of the fluorescent image of the fundus Ef is extremely low, making alignment and focusing adjustment impossible. When the user releases the operating button 31, the operating button 31 returns to its original state as shown in FIG. 3 due to the return force of the spring contact of the switch S3. In this state, the contacts Sa of the switch S3,
Sb and Sc become non-conductive with each other, and the solenoid 20
．． 21, the relay 4o is turned off, and the exciter filter 5 and barrier filter 11 are removed from the photographing optical path. At the same time, the contact S4 of the relay 40 also becomes non-conductive, so that the illumination light source 1 also emits the amount of light for color photography. Moreover, since this illumination light is white light for color photography, the fundus is very easy to see, making alignment and focusing easier.

Furthermore, since observation of a fluorescent image only needs to be performed several times out of several dozen shots, the photographer only has to press the entire stroke of the operation button 31 at once when shooting, and when aligning and focusing, Since the button 31 is released, the frequency with which strong illumination light enters the fundus E4 of the subject is extremely low. In other words, the suffering of the subject from glare from the illumination light can be significantly alleviated.

In addition, if the photographer wants to observe fluorescent images continuously,
By flipping the contacts S2a and S2b of the switch S2 from the C side to the second side, the solenoids 20 and 21 and the relay 40 can be operated, and at the same time, the first button of the operation button 31
This can be done with stroke operations.

Although a spring contact is used for the switch S3 in the gripping rod 30, a magnet may be provided at the bottom of the operation button 31, and reed switches may be used for the contacts Sa, Sb, and Sc.

As explained above, the fundus camera according to the present invention is designed to eliminate the troublesome task of repeatedly inserting and removing a barrier filter each time the fundus and camera are aligned and focused during fluorescence fundus photography. By simply operating the exciter filter and barrier filter from the optical path, the fundus can be detected in the same way as in color photography, making alignment and focusing easier to operate, and at the same time, the amount of light illuminating the fundus can be adjusted to the same level as in color photography. Since the same amount is sufficient, the subject can also avoid suffering from glare.

[Brief explanation of drawings]

FIG. 1 is a characteristic diagram of an exciter filter and a barrier filter, FIG. 4 and 5 are explanatory diagrams of its operation, and FIG. 6 is a block diagram of the electric control circuit. 1 is an observation light source, 3 is a photographing light source, 5 is an exciter filter, 11 is a barrier filter, 20 and 21 are solenoids, 30 is a gripping rod, and 31 is an operation button. Patent applicant: Canon Co., Ltd. Figure 3 (J

Claims (1)

[Scope of Claims] 1. A camera capable of photographing a fluorescent fundus, having an operation means for simultaneously inserting and removing an exciter filter and a barrier filter into an illumination optical path and a photographing optical path, and having an operation means for simultaneously inserting and removing an exciter filter and a barrier filter into and out of the illumination optical path and the photographing optical path; A fundus camera characterized by having means for causing a photographing light source to emit light at an arbitrary time after insertion of a barrier filter. 2. The operation switch for controlling both of the above means has a two-stroke operation.2 The first stroke inserts the exciter filter and the barrier filter into the illumination optical path and the photographing optical path, and the second stroke inserts the exciter filter and the barrier filter into the illumination optical path and the photographing optical path. The fundus camera according to claim 1, wherein the imaging light source is circuit-connected to emit light. 3. The fundus camera according to claim 2, wherein the amount of illumination light from the observation light source is increased in conjunction with the first stroke operation of the operation switch.