JPH068939B2 - Camera with battery check function - Google Patents

Description

The present invention relates to a camera having a battery check function.

Conventionally, when the power supply battery of the camera is exhausted and falls below a predetermined value required for automatic exposure control or automatic focus adjustment, shooting is performed without knowing it and inappropriate exposure control or focus adjustment is performed. There was an accident. As measures to prevent this, conventionally, there have been various means. For example, there is one provided with a release lock magnet that blocks a release when the power supply voltage is lower than a predetermined value.
This has the disadvantage of increasing space costs. In addition, there is also one in which the exposure control magnet and the release lock magnet are used in combination, and when the power supply voltage is lower than a predetermined value, the combined magnet is used to prevent the release, thereby preventing a failure in photographing. However, this also has a drawback that the release stroke is long and the weight of the release button is increased, which impairs the feeling of use and complicates the structure. Further, in the above conventional technique, when the release operation is performed,
Since the battery consumption will be known only when it is locked, there is a problem that the shooting opportunity when the release operation is performed is missed.

Therefore, if the power supply voltage becomes lower than the specified value,
A configuration in which the film is prevented from winding can be considered. However, during film winding, the load current becomes maximum due to the rotation of the winding motor, and the power supply voltage drops. Therefore, it is inconvenient if the film winding is stopped due to the voltage drop when the motor is rotated, even if the power supply voltage is such that the exposure control can be properly performed.

In order to solve such a drawback, the present invention has an object to prevent a photographing failure due to a power supply voltage drop with a simple configuration. Therefore, in the camera having the battery check function of the present invention, the power supply voltage during the exposure control operation is detected, and the film feeding operation / subsequent operation according to the voltage value is detected.
If the voltage value is equal to or higher than the predetermined value, the film feeding is not blocked even if the power supply voltage falls below the predetermined value during the film feeding operation after the exposure control operation is completed. I am trying.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a first reference example. Switch SW ₁ operates in conjunction with the shutter release button and is a terminal when the release button is pressed.
It switches from NC to terminal NO, and when the shutter release button returns to the original position, it switches from terminal NO to terminal NC again. Switch SW ₂ works in conjunction with shutter release and film winding. Switch SW ₂ switches from terminal NC to terminal NO when exposure is completed, and switch when film winding is completed.
SW ₂ switches from terminal NO to terminal NC again. The power supply 1 is the power supply of the camera. The resistors 2 and 3, the comparator 4, and the reference voltage source 5 form a voltage detection unit. The voltage of the reference voltage source 5 is applied to the non-inverting input of the comparator 4, and the voltage obtained by dividing the voltage of the power supply 1 by the resistors 2 and 3 is applied to the inverting input. When the voltage of the power supply 1 is higher than a predetermined value, that is, the lowest voltage value that can normally perform exposure control or focus adjustment, the voltage divided by the resistors 2 and 3 becomes higher than the reference voltage, and the comparator 4 becomes GND. That is, L output is generated. When the voltage of the power source 1 becomes lower than a predetermined value, the voltage divided by the resistors 2 and 3 becomes lower than the reference voltage, and the comparator 4 outputs Vcc. This output voltage Vcc turns on the transistor 7 via the resistor 6.
To Transistors 8, 9, 10, resistors 11, 12,
13, 14, 15, 16 and the motor M constitute a film winding means. "The capacitor 17 is charged when the switch SW ₁ is on the terminal NC side and SW ₂ is on the terminal NO side,
The charging current flows through the resistor 12 and the base of the transistor 8, and the transistor 8 is turned on. Next, the transistor 9 is also turned on, and the resistor 14, the transistor 9 and the resistor 11
A positive feedback loop is formed by this, and the transistor 8 is maintained in the ON state even after the charging current to the capacitor 17 is reduced. While the transistor 8 is ON, the transistor 10 is also ON. At this time, switch SW ₂ is at terminal N
Since it is on the O side, the motor M rotates to wind the film. The end detection circuit 18 detects the shooting of all the frames of the film, that is, the end of the film, and at that time, generates an output for turning on the transistor 19.

Next, the operation will be described.

First, it is assumed that the voltage of the power source 1 is equal to or higher than a predetermined value and the film has not reached the end. At this time, the output of the comparator 4 is GND and the transistor 7 is OFF. The termination detection circuit 18 turns off the transistor 19. Both switches SW ₁ and SW ₂ are closed on the terminal NC side.
Since the switch SW ₂ is on the terminal NC side, both terminals of the motor M are short-circuited to stop the motor M, and the emitter of the transistor 8 is separated from the cathode of the power source 1 so that the transistors 8, 9, 10 is OFF. Next, when the shutter release button is pushed down, power is supplied from the power supply battery 1. The automatic focus adjustment means and the automatic exposure control means (not shown) start to operate sequentially, and the switch SW ₁ is switched from the terminal NC to NO to discharge the capacitor 17.
Next, when the exposure is completed, the switch SW ₂ switches from the terminal NC to the terminal ON side. The emitter of the transistor 8 is connected to the negative side of the power supply 1, but the transistor 8 remains off because the capacitor 17 is discharged. Next, when the shutter release button returns to the original position, the switch SW ₁ switches from the terminal NO to the terminal NC side, and the charging current flows from the power source 1 to the capacitor 17 through the switch SW ₂ and the resistor 12. Therefore, a potential difference occurs between both terminals of the resistor 12, the transistor 8 is turned on, the transistor 9,
10 turns on. Although the charging current to the capacitor 17 decreases with time, the resistor 14, the transistor 9, and the resistor 11
Forms a positive feedback leap of the transistor 8 and maintains the ON state of the transistor 8. Therefore, the transistor 10
The ON state is also maintained, the motor M rotates, and film winding starts. Then, when the winding is performed by a predetermined amount, the switch SW ₂ is switched from the terminal ON to the terminal NC side to complete the motor M and the emitter of the transistor 8 is connected to the power source 1
The transistors 8, 9 and 10 are turned off by moving away from the cathode. In this way, it returns to the initial state.

Next, the operation when the film reaches the end will be described. In this case, the termination detection circuit 18 uses the transistor 19
Is turned on. Therefore, the transistors 8 and 10 are maintained in the OFF state regardless of the charging current of the capacitor 17. Even when the switch SW ₁ is switched from the terminal ON to the terminal NC side when the shutter release button is restored and the charging current flows through the capacitor 17, the transistors 8 and 10 remain OFF, and the power supply to the motor M is cut off. .

Next, the operation when the power supply voltage becomes equal to or lower than the predetermined value will be described. In this case, the voltage obtained by dividing the voltage of the power source 1 by the resistors 2 and 3 becomes lower than the voltage of the reference voltage source 5, so that the comparator 4 generates the Vcc output and turns on the transistor 7. Therefore, the transistor 8 is maintained in the OFF state. When the shutter release button is restored, switch SW ₁ is set to terminal N
Even if the charging current flows through the capacitor 17 by switching from O to the terminal NC side, the transistors 8 and 10 remain OFF, the motor M does not rotate, and film winding is blocked. Therefore, the photographing of the next frame is blocked, and the photographing failure due to the power supply voltage drop is prevented.

Various modifications can be made to the first reference example. For example, in the first reference example described above, the film winding is prohibited by applying the output of the comparator 4 to the transistor 7 and turning on the transistor 7 when the power supply voltage drops, but it is changed as follows. can do. That is, even if the collector / emitter of the PNP transistor is inserted between the terminal NC of the switch SW ₁ and the power supply 1 and the output of the comparator 4 when the power supply voltage drops is applied to the base, it is turned off. It is possible to prevent film winding at the time. Also, the collector / emitter of this PNP transistor is connected to the base / emitter of the transistor 9, respectively, and the output of the comparator 4 when the power supply voltage drops is applied to the base of this PNP transistor to turn it on. Even if the emitters are short-circuited, the film winding at this time can be prevented.

FIG. 2 shows a second reference example of the present invention. In the second reference example, the lamp for the film feeding display and the lamp for the battery check display are used together. The same parts as those in the reference example shown in the first illustration are designated by the same reference numerals. Light emitting diode 2
0 is used for both film feeding display and battery check. Switch SW ₃ repeats ON and OFF during film feeding. A current limiting resistor 21 is connected between the light emitting diode 20 and the switch SW ₃ . The transistor 22 is connected between both terminals of the switch SW ₃ , and the output of the comparator 4 is applied to the base of the transistor 22 via the resistor 23. The other structure is the same as that shown in the first illustration, and therefore omitted.

Next, the operation will be described.

First, if the film does not reach the end and the power supply voltage is higher than the specified value, the shutter release button is pressed down,
The same operation as that shown in FIG. 1 is performed until the exposure is performed and the shutter release button returns to the original position. When the shutter release button returns to the original position, the switches SW ₁ and SW ₂ open the terminals NC and NO, respectively. In this state, the motor M rotates to wind the film. At this time, switch SW ₃ repeats ON and OFF, so power supply 1 switches S
Power is supplied to the light emitting diode 20 intermittently via the W ₂ terminal ON, the switch SW ₃ , and the resistor 21.
0 is decremented to indicate film feed. The subsequent operation is the same as that of the first illustration.

Next, when the film reaches the end, the same operation as that shown in the first illustration is performed, and thus the description thereof is omitted.

Next, when the power supply voltage drops below a predetermined value, even if exposure is completed by pressing the shutter release button and the shutter release button returns to its original position, the same procedure as in the first reference example of FIG. 1 is performed. Switch to prevent film winding
SW ₂ is closed on the terminal NO side. When the exposure is completed, the switch SW ₂ is closed on the side of the terminal NO and then maintained in that state. Therefore, during this period, the transistor 22 is turned on by the output Vcc of the comparator 4, and the power supply 1 switches
A current flows through the light emitting diode 20 via the SW ₂ transistor 22 and the resistor 21, and the light emitting diode 20 steadily lights up to indicate a voltage drop.

FIG. 3 shows an embodiment of the present invention. In this embodiment, an RS flip-flop 30 is provided as a memory. The operation of this RS flip-flop 30 is as follows. While the clear input terminal CL has an H level input, the output terminal Q
Is held at L, and conversely, while the input terminal CL has an L level input, the level of the output terminal Q becomes equal to the input level of the set input terminal S at that time. To the clear terminal CL of the RS flip-flop 30, the delay circuit including the capacitor 31 and the resistor 32 and the collector of the transistor 9 are connected. The output of the comparator 4 is applied to the set input of the flip-flop 30. The Q output of the flip-flop 30 is connected to the gates of the transistors 7 and 22. The other structure is the same as that shown in FIG. The same parts as those in the second drawing are designated by the same reference numerals and the description thereof is omitted.

Next, the operation will be described.

First, the case where the film does not reach the end and the power supply voltage is higher than a predetermined value will be described. "First, the flip-flop 30 is in the reset state, that is, the level of the output Q is L." Since the power supply voltage is sufficiently high, the comparator 4
Applies the L output to the set input S of the flip-flop 30. Therefore, the Q output of the flip-flop 30 is L
Reply Therefore, the transistors 7 and 22 remain off. Thereafter, the same operations as in the first reference example shown in FIG. 1 are performed from shutter release to completion of winding.

Next, when the end of the film is reached and the power supply voltage is higher than a predetermined value, the transistors 22 and 7 are turned on as described above.
Is OFF. The transistor 19 is turned on and the winding is stopped. Hereinafter, the same operation as in the case of the second reference example shown in FIG. 2 is performed.

Next, a case where the power supply voltage is equal to or lower than a predetermined value will be described.
There are two cases for this. On the other hand, while the motor M is operating, the power supply voltage drops below a predetermined value because the load current of the motor M is large, but the predetermined value is maintained while the motor M is stopped and, for example, exposure control is performed. This is the case where the power supply voltage is the above. The other is the case where the power supply voltage is below a predetermined value over the entire period regardless of the operation of the motor M.

First, a case will be described in which the power supply voltage drops below a predetermined value during operation of the motor M, but rises above a predetermined value during stoppage thereof. In the initial state, the switches SW ₁ and SW ₂ are both closed on the terminal NC side, as in the reference examples shown in FIGS. ₁ and ₂ . Flip Flip 30 is in the reset state. At this time, since the motor M is not operating, the voltage of the power supply 1 is above the predetermined level, and the comparator 4 applies the L output to the set input of the flip-flop 30. Therefore, the flip-flop 30 remains in the reset state.

Next, press the shutter release button and press the switch.
SW ₁ switches to the terminal ON side.

Next, when the exposure is completed, the switch SW ₂ is switched to the terminal NO side. The operation before this is the same as that of the second reference example shown in FIG. Here, a charging current flows through the capacitor 17 through the terminal NO and the resistor 12 of the switch SW ₂ and the terminal NC of the switch SW ₁ , a potential difference is generated in the resistor 12, and the transistors 8, 9 and 10 are turned on. Therefore, power is supplied from the power source 1 to the motor M via the transistor 10, and the motor M
Rotates, and film winding is performed. At this time, the motor M
Since the load current is large, the voltage of the power supply 1 drops. Therefore, the output Vcc of the comparator 4 is applied to the set input of the flip slop 30, but at this time, the H level voltage is applied from the collector of the transistor 9 in the ON state to the clear input CL of the flip flop 30. Therefore, the flip-flop 30 maintains the reset state and its Q output remains L. Therefore, transistors 22 and 7
Also remains in the OFF state, and the rotation of the motor M is continued.

Next, a case where the power supply voltage is below a predetermined value over the entire period regardless of the rotation of the motor M will be described. Initially, flip-flop 30 is in the reset state. "Since the motor is stopped, the clear terminal CL of the flip-flop 30 is at L level." At this time, since the power supply voltage is below a predetermined value, the comparator 4 sets the Vcc output to the flip-flop 30. Applied to the input, the flip-flop 30 is set, the Q output goes high and the transistors 22 and 7 are turned on.

Next, when the exposure is completed, the switch SW ₂ is switched to the terminal NO side. Around the same time, the shutter release button returns to the original position and switch SW ₁ also switches to the terminal NO side. However, the transistor 7 is turned on by the flip-flop 30.
Therefore, the transistor 8 is maintained in the OFF state, and the transistors 9 and 10 are also in the OFF state. Therefore, the reset signal is not applied to the flip-flop 30, and the motor M does not rotate. Also, from power supply 1 to switch SW
_A current flows through the light emitting diode 20 through the _second terminal NO, the transistor 22 and the resistor 21, the light emitting diode 20 is steadily lit, and the power supply voltage is reduced. Since the film is not wound thereafter, the operation is stopped and this state is maintained. In this state, the power supply 1 is replaced with one that can output a voltage of a predetermined value or higher. Then, the delay circuit including the capacitor 31 and the resistor 32 applies the H level voltage to the reset terminal of the flip-flop 30,
The trip flop 30 is reset. At this time, since the output of the comparator is applied to the set input of the flip-flop 30, the Q output of the flip-flop becomes L. After that, the operation returns to the case where the power supply voltage is higher than the predetermined value.

Generally, the load current becomes the largest during operation when the film winding motor M is rotating. Therefore, even if the power supply voltage is sufficiently high when the motor M is stopped and the exposure control is performed, the power supply voltage may drop below a predetermined value when the motor M is rotating. In this case, since the exposure control is performed while the motor M is stopped, the exposure control is properly performed. Therefore, in this case, it is preferable that the rotation of the motor M is not stopped even if the voltage drops when the motor M rotates.

In the present embodiment, if the power supply voltage is higher than a predetermined position during the film winding operation, the detection result of the power supply voltage is stored and held even during the film winding operation. Therefore, if the power supply voltage is above the specified value before film winding and exposure control can be performed properly, the film winding is not blocked even if it falls below the specified value during film winding, and the next frame is not blocked. Exposure control is possible.

As described above, in the present invention, it is detected whether the power supply voltage during the exposure control operation in which the film feeding operation is not performed is equal to or higher than a predetermined value, and the detection result is held during the film feeding operation. Since the film feeding operation / blocking is controlled based on the detection result, the film feeding is not lowered even if the power supply voltage is reduced to a predetermined value or less before the film feeding, and the exposure of the next frame is prevented. The effect is that control, that is, photographing can be performed. This increases the number of frames that can be photographed in the manner of the power source. Further, since the means for detecting the exchange of the battery is provided and the state indicating the voltage drop is reset when the exchange of the battery is detected, the film feeding operation can be restarted promptly after the exchange of the battery.

[Brief description of drawings]

 FIG. 1 is a diagram showing a first reference example of the present invention, FIG. 2 is a diagram showing a second reference example of the present invention, and FIG. 3 is a diagram showing an embodiment of the present invention. [Explanation of Signs of Main Parts] M ... Motor 4 ... Comparator 18 ... Termination detection circuit 20 ... Light emitting diode 30 ... Flip-flop

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-52-110022 (JP, A) JP-A-55-129322 (JP, A)

Claims (2)

[Claims] 1. A battery, an exposure control means for performing exposure control by power supply from the battery, and a film feeding means for carrying out a feeding operation by power supply from the battery after the exposure control by the exposure control means is completed. A first power feeding control means for starting power feeding from the battery to the film feeding means in an initial operation corresponding to the exposure control operation to maintain a power feeding permission state, and the first power feeding control means. Is in the power supply permitting state, in response to the completion of the feeding operation, the power supply to the film feeding means via the first power feeding control means is mechanically switched from the permission state to the non-feeding state, and the next feeding is performed. The first power feeding control means supplies power to the film feeding means when the first power feeding control means is in the power feeding permitted state and also when the first power feeding control means is in the power feeding permitted state. 2 power supply control means, voltage detection means for detecting the voltage of the battery, generating a voltage normal signal when the voltage is equal to or higher than a predetermined value, and generating a voltage drop signal when the voltage is lower than the predetermined value, Storage means for storing the voltage normal signal or the voltage drop signal before the operation of the film feeding means and holding the memory even during the feeding operation by the feeding means; and the voltage normal signal in the storage means. If stored, the battery voltage does not respond even if the battery voltage falls below the predetermined value during the feeding operation, and if the voltage drop signal is stored in the storage means, the first When the voltage detection unit detects that the battery voltage is equal to or higher than the predetermined value when the battery is replaced, the power supply control unit is prevented from starting the power supply to the film feeding unit by the initial operation of the power supply control unit. Remembered Camera with a battery check function characterized by having a power feeding preventing means for canceling the power supply rejection to the second power supply control means via said first power supply control means resets said voltage drop signal. 2. The voltage detecting means includes display means that operates in a first display mode in response to the voltage drop signal and operates in a second display mode in response to the feeding operation. A camera having a battery check function according to claim 1.