JPS5849920A - Electrical feed controlling circuit for camera - Google Patents

Abstract

PURPOSE:To improve the operatively and economize in electric power, by switching the time from the start to the stop of the electrical feed to a photometric circuit to a proper length in accordance with a set exposure control mode. CONSTITUTION:When a program automatic exposure control mode is selected and a switch SW1 is turned on, the output of an AND gate AND4 becomes H, and the output of an NOR gate NOR becomes L. Switches SW3, SW1, SW2 are turned off. Consequently, the feed holding time of an exposure controlling circuit is set to the shortest time. When a manual exposure control mode is selected and a switch SW4 is turned on, the output of the NOR gate NOR becomes L, and the output of an OR circuit 3 becomes L, and switches SW1 and SW2 are turned off. Consequently, the feed holding time in the manual exposure control mode is set to the longest time. Thus, the time of the feed to the photometric circuit is switched in accordance with the exposure mode, and the operativity is improved, and electric power is economized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power supply control circuit for a camera, and particularly to a power supply control circuit that controls power supply to a second circuit of a camera.

Conventionally, as a circuit that controls power supply to a side light circuit included in an exposure control circuit, etc., power supply Y: is started to the side light circuit by pressing the shirt release button, etc., and then the side light circuit is operated for a certain period of time. Some devices automatically stop power supply after a certain period of time has elapsed. We waste electricity by forgetting to turn off the power switch in such a busy schedule! It was being prevented.

However, when using this type of power supply control circuit*V multi-mode exposure control, that is, automatic exposure control modes such as shutter speed priority, aperture priority, and program, or a side light circuit that allows manual exposure control, the following problems arise. occurs. In the manual exposure control mode, it takes a long time to operate because the aperture value, shirt, and speed settings are set manually, whereas in the automatic exposure control mode, the operation is completed in a short time. However, the power supply holding time during which the conventional power supply control circuit as described above supplies power to the side light circuit and operates it is constant regardless of the mode. If this power supply holding time is simply the average value of the time required in each mode, in the case of manual exposure control mode,
The drawback is that when manually operating the french value and shutter speed setting components, the power supply to the photometering circuit is stopped, resulting in an inoperable trap, and in the case of automatic exposure control mode, the photometering circuit continues to be used up even after the operation is completed. A drawback arises in that power is not supplied to the

An object of the present invention is to obtain a power supply control circuit for a camera that eliminates the above-mentioned drawbacks by switching the time Y from the start to the stop of power supply to the photometry circuit to an appropriate length according to the set exposure control mode. be.

The drawings show embodiment Y of the invention. The photometric circuit 1 is supplied with power from the power source @Wee via the first power switch sw, Y:. N
A counter consisting of an OR circuit NOR, an AND circuit AND, ~AND4, flip-flops FF, ~FF, and an oscillator O8C constitute a timer circuit 2tl.

This timer circuit 2 is a second power switch Sw.

Powered via. The operating switch sW is turned ON in conjunction with half-pressing the shirt release button. OR circuit 3
consists of two diodes. This OR circuit 3 is activated by pressing the shirt release button halfway.
When it becomes NK, the first and second power switches 5w5SW*
Turn on YON to start power supply to the photometry circuit 1 and timer circuit 2. Accordingly, the photometric circuit 1 starts operating. However, since the timer circuit 2 has been reset via the switches SW and Y at this time, timing does not start. Also, the output of the timer circuit 2 in this reset state is the OR circuit 3't
- via switch sw, and sw.

9ONKL, maintains power supply to photometry circuit 1 and timer circuit 2. Therefore, next, release the half-press of the shutter release button and turn the switch sw.

Even if YOFFK is performed, power supply to the photometric circuit 1 is maintained. On the other hand, when this switch SW becomes 0FPK, the timer circuit 2 is released from the reset Y, starts timing YN, and after measuring a predetermined time, output Y is generated, and switches SWl and swtv
OFFK to stop power supply to the side light circuit and the timer circuit 2 itself, rendering these circuits inoperable. Note that the length of time measured by the timer circuit 2 is determined by the switches SW4 to SW4.
W! is turned ON in conjunction with the settings of manual exposure control, shutter speed priority automatic exposure control, aperture priority automatic exposure control, and program automatic exposure control, respectively, and the respective control modes 1C1! The photometric circuit 1 and the timer circuit 2 are operated for the length of time required. Further, the switches gW, , 8W can be constructed from well-known electric switches such as transistors.

Next, I will explain the operation. By pressing the shutter release button halfway, the operation switch sw, go? lcj and switch sW & and O
To R circuit 31: H level voltage via switch sw, .
sw is applied, the switches SW,, SW, are turned on, and power supply to the side optical circuit 1 and the timer circuit 2 is started.
Side light circuit 1 starts 8Ill light. However, at this time, an H level voltage is applied to the flip 70 knobs FF, ~FF, and the glue set input of the timer circuit 2 through the switches SW and V, and the outputs of the flip flops FF and ~FF4 are L.
Then, the output of the AND circuit ANDi~AND becomes H, and the output of the NOR circuit becomes H.

Therefore, the H output of this NOR circuit NOR is sent to the switches SWi and SW via the OR circuit 3.

'1\: Turns ON and maintains the operation of the photometry circuit w11 and timer circuit 2. Next, release the shutter release button halfway and turn switch 8W and 'kOFF. In this state, power is supplied to the 1lI1 party circuit 1 and timer circuit 2 using the NOR
It is maintained by the circuit N0Rf) H output. on the other hand,
When switch 8W is turned off, the flip-flop becomes FF.

~FF4 is released from reset and starts counting the output t of oscillator 08C. At this time, it is assumed that, for example, a program automatic exposure control mode that does not require manual setting of aperture value or shutter speed is selected, and switch 8W is turned ON. In this case, one input of the 7-rip 70-rub FF becomes H because one input of the 7-rip 70-rub FF becomes H due to the crossing pulse from the oscillator O8C.
The DNO gate NOR power becomes H, and the NOR gate NOR
The output becomes L. Also switch SW.

It is now 90FF. Therefore, the output of the OR circuit 2 also becomes L, and the switch 8W1.

SW is turned OFF. Therefore, the power supply to the photometric circuit 1 and the timer circuit 2 is stopped, and these circuits become inoperable. That is, in the program mode, the power supply holding time of the exposure control circuit is set to be the shortest.

Also, manual exposure control mode is selected and switch SW4
is ON, one input of the AND gate AND becomes H, so when the output of the Freetub flop FF becomes H, the AND gate generates an H output, and as in the previous case, the NOR Gate NOR output rise.

The output of the OR circuit 3 becomes L, and the switches sw, , sw,
is turned off, and the power supply to the photometric circuit 1 and the evening/time circuit 2 is stopped. Here flip 70 knobs FF, ~FF,
Since the output of the oscillator OSC is divided into 2 times, 4 times, 8 times, and 16 times, the flip 70-tube FF is generated.
The time it takes for the output of , to become H is the flip-flop FF
, FF,, FF.

slower than Therefore, the time from the start to the stop of photometry is the longest in the manual exposure control mode. During this time, both the aperture value and shutter speed are manually set VC1! j
This is determined by taking into account the amount of time that the photometric circuit 1 will be supplied with power during manual setting. Also, when shutter priority mode is set, switch SW
, respectively, when the aperture priority mode is set, the switch SWe is turned on. The power supply holding time to the photometric circuit 1 is
In the former case, the shutter speed is set to length 8, and in the latter case, the aperture value is set to length 8, which allows manual setting of the aperture value. Book 5I!
In the embodiment, a flip-flop is used as the frequency dividing circuit, but if an arbitrary frequency dividing circuit χ is used, it is possible to arbitrarily set the time in each mode.

As described above, according to the present invention, the time from the start to the stop of one voltage to the photometric circuit is switched to suit the set exposure mode. Therefore, since the neutralization power supply is stopped and the photometry circuit does not become inoperable when setting the aperture value and shutter speed, operability is improved, and power is saved because no more power is supplied than necessary. .

[Brief explanation of the drawing]

The drawings are diagrams showing embodiments of the invention. 〔main! ! Explanation of part codes] FLLRJ party circuit ・・・・・・・・・・・・・・・・・・
・・・ 1 operation switch・・・・・・・・・・・・・・・
・SW. Timer circuit......2 power switch...Bw,,sw. Switching circuit ・・・・・・・・・・・・8W, ~
8W.

Claims (1)

[Claims] 1. A timer circuit that starts timing/Y in response to the operation of an activation switch and generates a timing completion signal when the counting time elapses; a power switch that becomes non-conductive in response to the completion signal; and a clock time switching circuit that switches the clock time to a time appropriate for the selected exposure control mode in response to selection of an exposure control mode; 1: Power supply control circuit for camera using IRF mold. λ The clock time switching circuit switches the clock time t to a first time when the manual exposure control mode is selected, and to a second time shorter than the scissors first time when the automatic exposure control mode is selected. A power supply control circuit for a camera according to claim 1, wherein the power supply control circuit is defined as Y'l mold.