JPS58195539A - Eye bottom camera 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 The present invention relates to a fundus camera device capable of obtaining clear fundus images without fog.

Figure 1 shows the basic optical configuration of a fundus camera.The fundus camera, which is placed just in front of the eye E, has an objective lens l, a hole Mirror 2. Imaging lens 3, quick return mirror 4, and eyepiece lens 5
is located. When the quick return mirror 4 is in the upward position A as shown by the solid line, the observer e can look into the eyepiece 5 and observe the fundus Ef within the eye E to be examined. In addition, when the quick return mirror 4 is descending as shown by the dotted line, on the reflection side,
A film camera 6 is arranged, which film camera 6 consists of a reimaging lens, a photosensitive film sensor and a dark box. On the other hand, the perforated mirror 2 includes, for example, an observation light source 7 consisting of a halogen lamp and a photography light source 8 consisting of a cannon tube.
Illumination light is incident thereon and illuminates the inside of the eye E to be examined. This fundus illumination optical system includes a condenser lens 9, a photography light source 8, another condenser lens 10, an annular slit plate 11, an optical path bending mirror 12, and Relay lens 13
．． 14 is arranged, and the illumination light from the observation light source 7 or the photographing light source 8 is bent by the optical path bending mirror 12 and enters the perforated mirror 2 via the relay lenses 13 and 14.

Therefore, when observing the fundus Ef, the light from the observation light source 7 is transmitted through the condenser lens 9, 10, the annular slit plate 11, the optical path bending mirror 12, and the mirror 12.

The light enters the perforated mirror 2 through the laces 13 and 14, is further reflected there, and illuminates the fundus Ef through the objective lens 1. At this time, the quick return mirror 4 has risen as shown by the solid line, and the fundus image is formed by the objective lens l, the perforated mirror 2,
It reaches the observer e via the imaging lens 3 and the eyepiece lens 5. On the other hand, when photographing with the film camera 6, the quick return mirror 4 is lowered to the position indicated by the dotted line by a solenoid (not shown), and at that moment the photographing light source 8 is turned on, and the fundus image is guided to the film camera 6. become. Then, after the photographing light source 8 is turned off, the quick return mirror 4 is returned to its original position, and the fundus camera enters the observation state.

However, the problem here is that the observation light source 7 continues to be lit even during shooting, so during the lowering and raising operations of the quick return mirror 4, the light from the observation light source 7 is not being used. It is reflected by the quick return mirror 4 and enters the film camera 6 as an unfocused image, giving a fog to the photographed frame.

Ru. 1. To solve this problem, use the quick return
Normally, a special shutter curtain is placed inside the mirror 4 and the film camera 6, and the shutter curtain is opened only when the quick return mirror 4 is lowered, but the structure is complicated. , leading to increased costs.

An object of the present invention is to provide a fundus camera apparatus which can obtain clear fundus images without fogging without using the above-mentioned special shutter curtain by not emitting light from the observation light source during the operation period of the optical path switching means. The gist thereof is to provide an observation light source, a photography light source, an optical path switching means for switching between an observation optical system and a photography optical system, and during the optical path switching period, the observation light source It is characterized by comprising a means for turning off the light.

The present invention will be explained in detail based on illustrated embodiments.

As shown in FIG. 1, a photodetector 15 is disposed between the quick return mirror 4 and the film camera 6, and a limit switch 16 is provided at the end of the quick return mirror 4 to detect its operating position. are in contact with each other.

FIG. 2 shows a dimming circuit for the observation light source 7 using a thyristor chopper system, in which the frequency of an oscillation circuit consisting of a variable resistor R1, a capacitor tc1, a unijunction transistor Tri, and a resistor R2 is changed by a variable resistor R1.
Thyristor SC in half-wave rectified wave from AC power supply v1
Shift the on phase of R and use observation light #! 7 dimming. Sl is a switching element composed of, for example, a transistor, a relay, etc. whose on/off is controlled by an external control signal from an external control circuit SC. It is activated by a detection signal of illumination light from the observation light source 7.

In the circuit shown in FIG. 2, when the quick return mirror 4 begins to descend, the photodetector 15 detects light, turns on the switch element S1 via the external control circuit SC, and keeps the capacitor C1 charged during this period. The observation light source 7 is turned off by stopping oscillation and not firing the thyristor SCR. Then, when the photographing is completed and the quick return mirror 4 is completely raised, the observation light source 7 is turned on again by the operation of the photodetector 15.

In addition, in the circuit of FIG. 3, the observation light source 7, the DC power source El,
In the series circuit of the variable resistor R3, a switch element S1 is inserted in parallel to the observation light source 7. In this case, the observation light source 7 is turned on with the switch element S1 turned off at all times, and when the quick return mirror 4 starts to descend, the switch element S1 is turned on via the external control circuit SC and the observation light source 7 is turned on. The light is turned off by shorting it. As described in the previous embodiment, the observation light source 7 is re-lit once the quick return mirror 4 has finished rising, and a description of this re-lighting will be omitted in the following embodiments as well. .

In the circuit of FIG. 4, the firing phase of the triac TR is changed to the firing phase of the triac D1. It is configured to dim the light by changing it using a variable resistor R4 and a capacitor C2. Here, by connecting the switching element St in series to the observation light source 7, the switching element S
1 is turned off, the supply of power v2 to the observation light source 7 is stopped, and the light is turned off.

Although the switch element S1 is actuated, a limit switch 16 that directly detects the actuation of the quick return mirror 4 may be connected in the circuit.

In Figure 5, the base of transistor Tr2 and the DC power supply E
A limit switch 16 is inserted between the transistor Tr2, and when the quick return mirror 4 is raised, the limit switch 16 is on, and the observation light source connected between the emitter and collector of the transistor Tr2. 7 is energized and lit. Here, when the quick return mirror 4 begins to descend and the limit switch 16 opens, the base of the transistor Tr2 is biased through the resistor R5, and the transistor Tr2 is turned on, stopping power supply to the observation light source 7 and turning off the light. , it turns out.

“...

Part 1 ``1 is a master flJI HJ 11 D k!8 e
There is Il'l II, the old M2 is ff1l t";,
, is a single pulse generating circuit triggered by a switch s2 provided, T'3 is a transistor that is turned on and off by the output of the pulse generating circuit M2, and SL is a solenoid that drives the quick return mirror 4. Here, When the switch S2 is instantaneously closed as shown in the signal in Fig. 7(a), the pulse generating circuit old and M2 is closed as shown in Fig. 7(b).
), the old level signal as shown in (c) is output.

The old pulse generation circuit is M2 as shown in Figure 7(a).
This time t3 corresponds to the transition time from the lowered position to the raised position of the quick return mirror 4.The old signal of the pulse generation circuit M2 shown in FIG. 7(c) During the period (tl+t2), the transistor Tr3 is turned on, and the quick return mirror 4 starts to fall during this period, or has fallen during the period t2, and the period after the signal of the pulse generation circuit M2 is inverted to Low. The quick return mirror 4 returns to the raised position within t3. Therefore, Fig. 7(b)
If the pulse generating circuit Ml is operated to turn on the transistor Tr4 corresponding to the above-mentioned switch element St during the period (t1+t2+t3) as shown in FIG. Become.

In the embodiment described above, the observation light source 7 is always turned off when the quick return mirror 4 is not in the 1-out position, but the operation of the quick return mirror 4 is actually affected by the rash. The observation light source 7 is turned on during the period, and if the Fink return mirror 4 is completely lowered and stopped, even if the observation light source 7 is turned on, there will be no significant influence. Therefore, it is actually necessary to turn off the observation light source 7 during the operating period of the quick return mirror 4, and there is no problem even if the circuit is configured so that it turns on when the quick return mirror 4 is stopped due to rising or falling. do not have. Furthermore, in the embodiment, the light flux from the fundus Ef is reflected by the quick return mirror 4 and guided to the film. Good too. Note that for fundus cameras that use a single light source lamp as both an observation light source and a photography light source by increasing or decreasing the light intensity, you can set the turn-off time immediately before increasing the light intensity and switching to the photography light source function. As explained above, the fundus camera device according to the present invention turns off the observation light source to prevent fogging caused by the observation light source when photographing the fundus image with film, so that, for example, quick return is possible. An optical path switching mechanism such as a mirror can be used in place of the shutter curtain, and at the same time a high quality photographic image can be obtained and the apparatus can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a basic optical configuration diagram of a fundus camera, and FIG.
6 to 6 are block diagrams of circuits for turning on and off the observation light source, respectively, and FIG. 7 is a time chart diagram of the circuit of FIG. 6, (a) is the output signal of switch S2, (b)
, (c) is the pulse generation port □1. M2 (7) Receive the output signal. :1' 4 is a quick return mirror, 5 is an eyepiece with a 1□-゛ lens, 6 is a film camera, 7 is a light source for observation, 8 is a light source for photography, 15 is an optical path detection means, 16 is a limit switch, and St is a In the switching element, SC is an external control circuit, and Ml and 2 are pulse generating circuits. @11 1112 drawing 3 @ 459 2 Striped 5 drawing 117 drawing

Claims (1)

[Scope of Claims] 1. A light source for observation and a light source for photographing are provided, and an optical path switching means is provided for switching between the optical system for observation and the optical system for photographing, and the light source for observation is turned off during the optical path switching period. A fundus camera device characterized by comprising means. 2. The fundus camera device according to claim 1, wherein the retinal camera device detects that the optical path switching means is activated and stops supplying power to the observation light source. 3. The fundus camera device according to claim 1, wherein the optical path switching means is a quick return mirror. 4. The fundus camera device according to claim 3, wherein the operation of the quick return mirror is detected by a limit switch. 5. The fundus camera device according to claim 1, wherein the observation light source is turned off at a predetermined time interval while emitting a signal for activating the optical path switching means.