JPS62169133A - Checking device for battery of camera - Google Patents

Abstract

PURPOSE:To surely prevent the occurrence of an affair where a photographing sequence cannot be continued halfway, by providing a counter which counts the actuation f a load circuit and performing battery checking whenever the count value reaches a prescribed value. CONSTITUTION:Electric currents for driving shutter driving circuit 34, motor driving circuits 36 and 42, etc., are supplied from a battery pack and a battery checking circuit 50 is provided to detect the consumption of the power source. When the division of a voltage level is discriminated by binary coding signals inputted to the input terminals I1 and I2 of a CPU 30, LEDs 24 and 25 are driven through an LED driving circuit 60 in accordance with the division. A counter 62 performs counting operations whenever the shutter driving circuit 34, motor driving circuits 36 and 42 which are circuit loads are actuated. Furthermore, the counting operations are weighted by taking the power supply consumption of these circuit loads into consideration.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a camera pantry check device that automatically and periodically checks the power supply voltage.

[Conventional technology]

In recent electronic cameras, the shutter and film winding mechanism are electrically driven using solenoids and motors, and the shooting sequence, from shutter activation to film winding, is controlled by a microcomputer. That's what I do. In such a camera, if the power supply voltage falls below a certain level, not only will each mechanical part acting as a circuit load not work properly, but it will also interfere with the transmission and reception of signals between these mechanical parts and the microcomputer. This results in confusion in the shooting sequence and unexpected malfunctions.

To deal with this, a pantry check device is used to monitor the power supply voltage. As a battery check device used for this purpose, there is a device that detects the voltage level by constantly passing a portion of the actual load current of the camera through a measuring resistor. According to this, unlike a battery check device that is activated by pressing a manual button, it is possible to prevent forgetting to operate the battery check device.

[Problem that the invention seeks to solve]

By the way, large format cameras that use 120 film, etc., consume a large amount of current, and the power capacity of normally used dry batteries is insufficient. Batteries are increasingly being used. In addition to being able to be used repeatedly by being recharged, NiCd batteries have the advantage of having a small internal resistance and being able to stably supply a large current, making them excellent as power batteries for cameras such as those mentioned above.

However, for batteries with low internal resistance, such as NiCd batteries, when voltage is detected using the actual load current as in the conventional pantry check device, the change in current value is small, so power consumption is reduced. A voltage level drop cannot be detected until it becomes significant. Therefore, by the time a drop in voltage level is detected, the power source is often almost exhausted. As a result, the power supply voltage, which was at an appropriate level before the start of photography, drops to an inappropriate level during the photography sequence, which may result in a situation where, for example, film winding, which consumes a large amount of current, cannot be completed.

The present invention has been made in view of such prior art,
To provide a camera battery check device which can surely prevent a situation where a photographing sequence cannot be continued in the middle.

[Means for solving problems]

In order to achieve the above object, the present invention automatically and periodically performs a battery check immediately before a shooting sequence is started, and the power supply voltage level at this point is such that a series of shooting sequences is interrupted. I try to check whether it is at a level where it can be executed without any problems. This battery check operation is configured such that a counter is incremented each time a load circuit that is a load on the power supply is operated, and is executed each time the counted value reaches a certain value.

According to a preferred embodiment of the present invention, the battery check is performed such that the change in current increases as the power source is depleted.
This is done by momentarily passing a current several times the actual load current through a dummy resistance for measurement. As a result of the battery check, if the power supply voltage is equal to or higher than the appropriate level, the next battery check is performed after the prescribed photographing sequence has been performed a certain number of times as described above. Furthermore, as the battery checks are repeated, the power supply voltage drops below the above-mentioned appropriate level, and although it is difficult to continue executing the above-mentioned number of shooting sequences, some shooting sequences can still be continued. When the voltage drops to a certain level, it is possible to warn that the power supply life is nearing the end.

An embodiment of the present invention will be described below with reference to the drawings.

〔Example〕

In FIG. 5 showing the external appearance of a camera using the present invention, a mounting surface 3 for mounting a film back 2 is formed on the back surface of a camera body 1. This mounting surface 3
is provided with a mounting bracket 4 for holding the film back 2 in a bayonet manner so as to surround the exposure aperture 3a, and for electrical connection between the camera body 1 and the film back 2. Contact portions 5a and 5b are provided for this purpose. When the film back 24 is attached to the camera body 1 in the normal position, one contact part 5a is connected to the contact part on the film back 2 side, and the film back 2 is rotated 90'' to the right by rotating the film back 24. Sometimes, the other contact portion 5b is connected to the contact portion of the film back 2.

The film back 2 has a built-in film winding mechanism that is RIM'd by a motor.
The film 7 loaded in the film back 2 is automatically wound one frame at a time in response to a signal output from the side. Further, a light shielding plate 8 is inserted into the film back 2 so as to be freely drawn out. This light shielding plate 8 is intended to prevent the film 7 loaded therein from being exposed when the film magazine 2 is installed or replaced, and is pulled out during photographing.

A pair of guide tubes 9 are protruded from the front surface of the camera body 1, and guide the movement of the extension base 11 supporting the lens board 1O in the optical axis direction. 12 is provided, and a lens unit 13 containing a built-in photographic lens is fixed to the lens board 10 by the lock claw 12. On the mounting surface of each of the lens board 10 and the lens unit 13, similar to the case of the film back 2 is provided. A signal contact 12 is provided for transmitting and receiving electrical signals to and from the camera body l, and a lens unit 1 is mounted on the lens board 10.
3 is attached, the shutter built into the lens unit 13 is activated by a signal from the camera body 1.

Note that the reference numeral 14 indicates a bellows that optically connects the back surface of the lens board 10 and the front surface of the camera body 1.

A focus plate 15 is installed on the top surface of the camera body 1. The photographing light beam from the photographing lens 16 fixed to the lens unit 13 is reflected by a reflex mirror 17 rotatably provided within the camera body l, and is reflected by the focusing plate 15.
is imaged. Note that at this time, the lens unit 13
Although the built-in shutter is open, a shielding plate 18 is placed behind the reflex mirror 17 to prevent light from leaking into the film back 2. Then, by operating the release button 19, the shutter is once closed, and then the reflex mirror 17 and the shielding plate 1 are closed.
8 rises, and then the shutter opens and closes at a predetermined time to perform exposure. Before shooting, operate the mode setting dial 20 to select normal shooting for each frame, continuous shooting,
Alternatively, the operator sets which multiplex photographing is to be performed, and operates the shutter dial 21 to select a desired shutter speed.

Outside the frame of the focus plate 15 are a green light emitting diode (hereinafter referred to as LED) 24 and a yellow light emitting diode 2.
5 are juxtaposed. These LEDs 24 and 25 are
It is detachably attached to one side of the camera body 1 and is used to display the result of a battery check of a battery bag 27 used as a power source for operating the camera. As a result of the battery check, when the power supply voltage is at an appropriate level, the LED 24 emits light; when it is at a warning level, the LED 24 turns off and the LED 25 flashes; and when the voltage level drops to an inappropriate level, the LED 24, 25 are both turned off.

In FIG. 1 showing the circuit configuration used in the above camera, blocks A, B, and C surrounded by broken lines represent the camera body 1. Film back 2. A circuit portion built into the lens unit 13 is shown. Rotate the mode setting dial 20, which also serves as the main switch S0 (Fig. 2) for powering on, from the OFF position to select the normal shooting mode index (index rsJ'') and the quick shooting mode (index r
cJ).

When set to any of the multiple shooting modes (index "M"), the setting position is determined by the mode detection circuit 28, and the CPU 30
Power is supplied to the CPU 30, and the CPU 30 enters a standby state.

For example, when the mode setting dial 20 is set to the normal shooting mode with the index rSJ, the shutter button 1
When the press operation No. 9 is detected by the release detection circuit 33,
The CPU 30 starts processing according to the normal photographing sequence program stored in the ROM 31. In this case, the CPU 30 first outputs a drive signal to the shutter drive circuit 34 built in the lens unit 13, thereby closing the shutter 35. After that,
An operating signal is supplied to the motor drive circuit 36, and the motor 37 is driven to raise the reflex mirror 17. The shielding plate 18 is also raised by the drive of the motor 37 via a well-known interlocking mechanism.

When the reflex mirror 17 and the shielding plate 1 completely reach the raised position, a signal is output from the reflex mirror position detection device 39 to the CPU 30 via the photosensor 38a. Thereby, the CPU 30 operates the shutter drive circuit 34 again. Then, the shutter 35 is opened and closed at the shutter speed selected by the shutter dial 2I, and the film 7
to expose. Note that the aperture value is set in advance on the lens unit 13 side.

When the exposure is completed in this way, a shutter operation completion signal is obtained from the shutter position detection circuit 41 that detects the mechanical displacement of the shutter 35, and this signal is input to the CPU 30. As a result, from the CPU 30, the motor drive circuit 3
A reversal signal is output to 6, and the reflex mirror 17 and the shielding plate 1 return to their lowered positions. When it is detected by the photo sensor 38b and the reflex mirror detection circuit 39 that these have completely returned to the lowered position, the motor drive circuit 42 built in the film back 2 is activated in response to a signal from the CPU 30, and the film is wound up. motor 43 is driven. The film 7 is transported by the drive of the motor 43, and when the amount of transport reaches exactly one frame,
A winding stop signal is output to the CPU 30 by the photosensor 44 and the film winding detection circuit 45 . As a result, a drive stop signal is output from the CPU 30 to the motor drive circuit 42, and the motor 43 is stopped. Then, the shutter drive circuit 34 charges the shutter 35 and one normal photographing sequence is completed.

Note that when the mode setting dial 20 is set to the continuous shooting mode with the index "C", the reflex mirror 17 and the shielding plate 18 are closed while the release button 19 is pressed.
, opening and closing of the shutter 35, down movement of the reflex mirror 17 and shielding plate 1B, film winding operation,
Then, the shutter charging operation continues repeatedly. In addition, in the multiple shadow mode, even if one exposure is completed by the operation of the shutter 35, the motor drive circuit 42 is not activated and winding of the film 7 is omitted, allowing multiple exposures of the same film frame. Be able to give. Then, when the mode setting dial 20 is released from the multiple shooting mode position and set to the normal shooting mode position or the continuous shooting mode position, the film 7 is transported by one frame.

The shutter drive circuit 34. Motor drive circuit 36.42
Current for driving the circuits and the like is supplied from the batch leaver 727, but the power supply is consumed each time these circuit loads are operated. To detect this power consumption,
A battery check circuit 50 is provided. This battery check circuit 50, as shown in FIG.
It is instantaneously activated by a pulsed high level signal (hereinafter referred to as H signal) output from terminal S of PU30. When the H signal is output from the terminal S of the CPU 30, a current flows through the dummy resistor 52, and the voltage level VB of the battery bank 27 can be detected. Note that the battery check circuit 50 and the shutter drive circuit 34. The voltage for operating the load circuit 54 such as the motor drive circuit 36.42 is a voltage stabilized by the voltage stabilization circuit 53. obtained as.

The voltage level V of the battery pack 27 is compared by a comparator 57.58 with the terminal voltage v1rVt of a resistor 55.56 that divides the stabilized voltage VD.

As shown in FIG. 3, these terminal voltages V, , V, are set to values that divide the voltage level vll into appropriate level, 9 warning level, and inappropriate level, and the input terminal of the CPU 30 is The table below shows the binary signals appearing at the output terminals of the comparators 55 and 56 that are input to the .

The classification of voltage levels in this table is determined based on the number of times the normal imaging sequence is repeated; an appropriate level is about 5 times or more, a warning level is about 2 to 4 times, and an inappropriate level is about 1 or more times. It means a voltage level below that level. Note that since the dummy resistor 52 is set to a low value compared to the actual load of the load circuit 54, its current value changes color by several times to ten times the actual load current, and detection is performed based on this. Power supply voltage v8
The level drop in power consumption is as shown by the solid line in FIG. 3. Therefore, the detection accuracy especially when the power consumption progresses can be improved more than the voltage level drop characteristic based on the actual load current shown by the broken line in the figure.

When the voltage level classification is determined by the binary signals input to the input terminals It and Ig, the LED
The LEDs 24 and 25 are driven via the drive circuit 6o.

As a result of the judgment, if this is the appropriate level, the LE emits green light.
Only D24 emits light, and when the warning level is reached, the yellow light emitting LED 25 flashes, and when the level is inappropriate, the LED
Both D24 and D25 go out, and the battery check result is displayed to the user.

By the way, the timing for performing the above-mentioned battery check is determined by referring to the count value in the counter 62.
This is done automatically according to the flow shown in the figure. As is clear from the flowchart in FIG.
4. A counting operation is performed every time the motor drive circuit 36, 42 is activated.

Moreover, considering the power consumption of these circuit loads, the counting operation is weighted, and the reflex mirror 1
7 up and down respectively, the count up is +1, one operation of the motor drive circuit 42 for film winding causes a count amplifier of +3, and one operation of the shutter drive circuit 34 for shutter charging. When activated,
+1” count up.

When the main switch S is turned on by rotating the mode setting dial 20 from the OFF position, a battery check is first performed. As a result, when the voltage level V of the battery back 27 is less than vl, that is, at an inappropriate level, both the LEDs 24 and 25 remain off, and no further camera operation is performed. After an initial battery check, if this is at the correct level, the shutter 35. After confirming whether the reflex mirror 17 is at the initial position and film winding has been completed, it is possible to carry out photographing. Note that when the shutter position detection circuit 41, the reflex mirror position detection circuit 39, or the film winding detection circuit 45 detects that these are not at their normal initial positions, the shank drive circuit 34. Motor drive circuit 36.4
2 to return them to their initial positions. At this time, count pulses weighted according to the amount of power consumed by each operation are supplied from the CPU 30 to the counter 62, and the counter 62 integrates and counts the pulses.

Thereafter, when the camera is released, the reflex mirror 17 is moved up, the shutter 35 is opened and closed, the reflex mirror 17 is lowered, the film is wound, and the shank charge process is executed. The counter 62 will count "6" due to this normal shooting sequence, but if this count is less than "30", the next normal shooting sequence will be started without battery check. A standby state is obtained. While the release is further being performed, when the count value of the counter 62 becomes "3o", that is, the normal shooting sequence is repeated five times, a battery check command is output from the output terminal S of the CPU 30 in response to a signal from the counter 62. The battery check is performed for the second time, and at the same time, the count value of the counter 62 is reset to "0".

As a result of this battery check, if this is the appropriate level, the count value of the counter 62 will continue to be “30”.
” The battery check is repeated every time the battery is exceeded. When the battery is checked several times and it is determined that vl≦vm≦v2, that is, the warning level is reached, the yellow LED 25 flashes to indicate the time to replace or charge the battery pack 27. In addition, after ■≦vt, the count value of the counter 62 is "6" or more in the shadow damage standby state, that is, the power consumption due to the operation of the circuit load is equivalent to the execution of one normal imaging sequence. A battery check is performed each time the voltage reaches V, and in principle this state continues until V<V. As already mentioned,
In the warning level state, there is enough power left to last at least one or two normal shooting sequences, so even if you shoot in this state, the power will turn off while the circuit load is operating. There is no such thing as being exhausted.

When the mode setting dial 20 is set to the multiple shooting mode, unlike the above-mentioned normal shooting mode, the film winding operation for each shooting is omitted, and the count-up operation on the counter 62 is reduced accordingly. However, when the voltage level is at an appropriate level, the battery check is performed when the count value of the counter 62 reaches "30", and when the voltage level is at a warning level, the battery check is performed when the count value of the counter 62 reaches "6". The same thing applies.

In this way, the shutter drive circuit 34. Motor drive circuit 3
The count-up value of the counter 62 that determines the timing of the battery check is weighted according to the power consumption of the circuit load such as 6.42, and the judgment level of the battery check is set between the inappropriate level and the appropriate level. If you also set a warning level, the battery will be checked automatically every time the power consumption gets more or less constant while monitoring the operation of the circuit load.

Moreover, in this warning level state, execution of at least one normal photographing sequence is guaranteed, so if the power supply is exhausted, the shutter drive circuit 34° motor drive circuit 3
This is effective in preventing the operation of a circuit load such as 6.43 from being interrupted midway.

Note that the present invention is equally applicable not only to large-format cameras that use secondary batteries as power sources as in the above embodiments, but also to 35 mm cameras that use ordinary dry batteries as power sources. Furthermore, it goes without saying that various types of load circuits, such as autofocus devices and strobe charging circuits, can be used as load circuits for the power supply.

〔Effect of the invention〕

As described above, in the battery check device of the present invention, a counter is incremented each time the load circuit that is a load on the power supply is operated, and when the count value reaches a predetermined value, the counter is automatically incremented. The voltage level of the power supply is measured by passing current through a resistance means for voltage measurement. Therefore, compared to conventional pantry check devices that perform battery checks while constantly monitoring the actual load current, highly accurate detection can be achieved. In addition, the current for voltage level measurement is applied instantaneously, and battery checks are periodically performed using a counter, taking into account the shooting sequence, so power consumption due to battery checks can be kept low. .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a control circuit of a camera using the present invention. FIG. 2 is a circuit diagram showing an example of a circuit configuration used in the battery check device. FIG. 3 is a graph showing voltage determination levels for battery check. FIG. 4 is a flowchart showing the battery check process. FIG. 5 is an external view of a camera using the present invention. 1...Camera body 2...Film back 17.
・Reflex mirror 24.25・・LED30・・
CPU 34...Shutter drive circuit 36.42...Motor drive circuit 50...Battery check circuit 62...Counter.

Claims (2)

[Claims] (1) In a camera battery check device that determines whether the voltage level of the power source for operating the camera is above a specified level, it counts when a load circuit that is a load on the power source is activated. A camera characterized in that a counter is provided, and each time the counted value of the counter reaches a predetermined value, current is instantaneously passed through a resistance means for measuring the voltage level of the power source to perform a battery check. battery check device. (2) The load circuit is composed of a plurality of drive circuits, and each drive circuit outputs a count value weighted according to the electrical energy consumed for each operation to the counter, and the cumulative value in this counter is 2. The camera battery check device according to claim 1, wherein the battery check is performed when the count value reaches a predetermined value.