JP2940057B2 - Camera battery check device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery check device for a camera using a battery as a drive source.

[Conventional technology]

A battery is widely used as a power source for camera control and operation such as focus adjustment, exposure control, flash emission, film winding / rewinding, and the like. In a camera using a battery of this type as a power source, the power of the battery is gradually consumed by repeating photographing, and when the terminal voltage falls below a specified value, an exposure control member such as a shutter does not operate normally and photographing fails. Will be. Therefore, the photographer is encouraged to change the battery before this happens,
Alternatively, a battery check device that periodically checks the terminal voltage of a battery in order to prohibit the operation of the camera when the normal operation of the camera may not be performed is already known.

[Problems to be solved by the invention]

By the way, such a battery check device is configured to compare the terminal voltage of the battery with the reference voltage at a predetermined time in various sequences of the camera, but once the terminal voltage of the battery is lower than the reference voltage. Is determined,
When a warning is displayed, the warning remains lit until the next battery check is performed.

There is no problem if the terminal voltage drops due to actual battery consumption.However, when a large current is continuously extracted (for example, when the flash is used continuously), a new battery is required. Even in such a case, the internal characteristics of the battery may temporarily change and the terminal voltage may decrease. In such a case, if a battery check is performed and the warning display is turned on, the battery characteristics are restored after a while, and the warning display remains lit even though the terminal voltage rises to the reference voltage or more, and is not necessarily. Accurate displays were not always made.

In addition, since accurate checking cannot be performed unless a predetermined load is applied to the battery in order to check the battery, the battery check consumes a certain amount of power. In order to always perform an accurate warning display, it is necessary to shorten the repetitive synchronization to some extent if the battery check is to be performed at fixed time intervals regardless of the camera status. There was a problem that it increased.

[Means for solving the problem]

In order to solve the above problem, the present invention checks the terminal voltage of a battery after a predetermined time has elapsed after entering the standby state, in addition to when the camera enters the standby state, and when the camera enters the standby state, a warning is issued. A camera that updates a display or the like and has an operation mode in which a shooting operation and an operation related to shooting are being performed, and a standby mode in which the operation mode is entered after completion of the operation and returned to the operation mode by a next switch operation. In a battery check device suitable for a camera provided with a control means, a battery voltage discriminating means for comparing a terminal voltage of the battery with a predetermined first reference voltage and a second reference voltage, and the terminal voltage of the battery is determined by the battery voltage discriminating means. A warning means for displaying a warning when it is determined that the voltage is lower than the first reference voltage and higher than the second reference voltage; Prohibiting means for prohibiting the control operation of the camera when it is determined that the terminal voltage of the camera is lower than the second reference voltage; mode determining means for determining whether the control state of the camera is in the operation mode or the standby mode; When it is determined by the mode determination means that the control state of the camera is in the operation mode, the battery voltage determination means is operated. Thereafter, when it is determined that the control state of the camera is in the standby mode, the operation mode is changed from the standby mode to the standby mode. And a battery voltage discriminating means for activating the battery voltage discriminating means after a lapse of a predetermined time after the shift to.

[Action]

When the control state of the camera is in the operation mode, the terminal voltage of the battery is repeatedly compared with the first and second reference voltages in the control operation processing, and the state of the warning display is updated based on the result, or The control operation of is prohibited. Also,
When the control state of the camera is in the standby mode, the terminal voltage of the battery is compared with the first and second reference voltages after a lapse of a predetermined time after the transition from the operation mode to the standby mode, and the state of the warning display is changed. Update. As a result, even if a warning message is displayed once, when the battery recovers thereafter, the warning message is turned off. Further, when the mode is shifted to the standby mode, the battery check interval becomes longer, so that unnecessary power is not consumed.

〔Example〕

Hereinafter, embodiments of the present invention will be described. FIG. 1 is a block diagram of a control circuit of a camera incorporating a battery check device of the present invention. In the figure, reference numeral 11 denotes a control CPU for controlling the entire operation of the camera, and details of the control operation will be described later. Reference numeral 12 denotes a photometric circuit for measuring the field luminance, and the measured field luminance signal is input to the control CPU 11. Reference numeral 13 denotes a distance measuring circuit for measuring a subject distance, and a measured subject distance signal is input to the control CPU 11. 1
Reference numeral 4 denotes a shutter driving mechanism that drives the shutter in accordance with an exposure control value computed by the control CPU 11 by a known method based on the measured field luminance and a separately input film sensitivity signal. Reference numeral 15 denotes a flash unit which controls the emission of a flash lamp based on the flash photographing information calculated by the control CPU 11. 16 is a film drive motor, which is a film 1 output from the control CPU 11
The film is wound up by one frame based on the frame rewind signal, and the film is rewound based on the film rewind signal. Reference numeral 17 denotes a display device which displays information indicating the state of the battery, in addition to various shooting information output from the control CPU 11. Reference numeral 18 denotes a battery check circuit, which includes a switch circuit 18a, an A / D converter 18b, a dummy load resistor RL connected to the battery BAT during battery check, and a voltage dividing resistor RD connected in parallel with the dummy load resistor RL. When the battery check start signal is output from the CPU 11, the switch circuit 18a is closed, the dummy load RL is connected to the battery BTA, and the terminal voltage of the battery BAT in the state where the load is connected is divided by the voltage dividing resistor RD and the A / D converter. 18
It is configured to input to the control CPU 11 via b.
Reference numeral 19 denotes a driver interface.

The battery check is performed by inputting the voltage between the terminals to the control CPU 11 via the voltage dividing resistor RD and the A / D converter 18b with the dummy load RL corresponding to the load of the shutter driving mechanism connected between the terminals of the battery BAT. Then, the battery is divided into the following three states in comparison with the predetermined two levels of the reference voltage,
Take action according to each level. That is, when the voltage between terminals is equal to or higher than the warning level voltage ... The battery level is sufficient and no warning is displayed.

When the voltage between terminals is lower than the warning level voltage and higher than the lock level voltage ... The remaining battery level is low, but shooting is possible for a while, so a warning is displayed to prompt the user to replace the battery.

When the voltage between terminals is lower than the lock level voltage: The operation of the camera is locked because the remaining battery power is insufficient and the camera is in a shooting impossible state.

The outline of the battery check has been described above.
Details of the battery check process executed in step 1
This will be described with reference to the flowchart shown in FIG.

Next, switches will be described. SM is the main switch. When ON, all functions of the camera, namely photometry, ranging,
Exposure control, film winding / rewinding, and the like are enabled. S1 is a switch which is turned on when the shutter release button is depressed to the first stage, and starts a photometry and a distance measurement operation. S2 is a switch that is turned on when the shutter release button is pressed down to the second stage, and starts a shutter release operation. SFL is a switch for selecting a flash photography mode. When ON, the flash photography mode is set, and when OFF, natural light photography is performed. S
RC is a switch that detects the opening and closing of the camera's back cover. It turns on when the back cover opens, and turns off when it closes. SDR1 is a film rewind start switch. When ON, rewinding is started.
SDR2 is a switch that turns ON when the end of the film is reached during film winding and the film cannot be wound. Automatic rewinding of the film is started. These switches output an “L” level signal to the control CPU 11 when turned on, and output an “H” level signal to the control CPU 11 when turned off.

Next, control processing executed by the control CPU 11 will be described with reference to the flowcharts shown in FIGS. First, the overall flow will be briefly described.

When the battery is inserted into the camera, the control process starts, and after the initialization process, the state of change of switches is checked. Since the state of the switch examined in the previous loop is stored in each flag, the current state is compared with the previous state, and if a switch has changed, the corresponding flag is processed by performing a corresponding process. To update. If there is no change in the switches, a standby process described later is performed at the end of the loop and the process returns to the beginning of the loop. Since the standby processing is executed only when the camera is in the standby state, when this processing is executed, it is determined that the camera is in the standby state, and the processing in the standby state performed in the present invention is the standby processing. Processed in Hereinafter, the details will be described with reference to the flowchart of FIG.

When the battery is inserted into the camera and control processing is started, first, various registers, RAM, flags of the control CPU 11 and control elements of the camera are initialized (step P1). The state of the main switch SM is checked (step P2). If it is ON, the display device 17 is turned on (step P3), and the counter K (the counter K will be described later in detail) is reset to 0 (step P4). If the main switch SM is not ON, step P3 is omitted. Check the state of the back cover open / close detection switch SRC (Step P5). If it changes from OFF to ON, perform the initial load (Step P6) and Step P4
Return to Main switch S if switch SRC is not ON
The state of M is checked (step P7), and when it changes from OFF to ON, a battery check described later is performed, the result is displayed on the display device (steps P8 and P9), and the process returns to step P4.
If the main switch SM has not changed from OFF to ON, the state of the main switch SM is checked (step P10). If the main switch SM has changed from ON to OFF, the display device is turned off (step P10).
11) Return to step P4.

If the main switch SM has not changed from ON to OFF in step P10, the state of the main switch SM is checked (step P12). If it is ON, the film rewind start switch SRD
The state of 1 is checked (step P13). When the switch SRD1 changes from OFF to ON, the film rewinding is started (step P14), and the process returns to step P4. If the film rewind start switch SRD1 has not changed from OFF to ON, check the status of the flash photography mode selection switch SFL (step P15). If it is ON, check whether the main capacitor of the flash unit is fully charged. Check (Step P1
6). If charging is not completed, charge the battery (step P1
7) Return to step P4. Switch in the judgment of step P15
When the SFL is not ON, and when the charging is completed as determined in step P16, the state of the switch S1 for starting photometry and distance measurement is checked (step P18). If the switch S1 has not changed from OFF to ON, a standby process described later is performed. Execute (Step P19) and return to Step P5.

If the switch S1 has changed from OFF to ON in the determination of Step P18, a battery check, which will be described later, is executed (Step P20), and photometry / distance measurement and calculation of exposure control values are executed (Steps P21, P22). . The state of the switch S1 is checked (step P23). If it is not ON, the process returns to step P4. If it is ON, the state of the switch S2 is checked (step S2).
4) If not ON, return to step 23. That is, in this embodiment, AE / AF lock is performed without performing photometry and distance measurement again. If the switch S2 is ON in the determination of step P24, execution of shooting has been instructed, so that the shooting lens is set to the in-focus position (step P25), and exposure control, that is, based on the previously calculated exposure control value, is performed. Then, the shutter is driven to execute flash emission control (step P26). When the photographing is completed, the photographing lens is reset to the initial position, and the film is wound up by one frame (steps P27 and P28). The switch SRD2 detects that the end of the film has been reached during the film winding, and determines whether or not the flag has been set (step P29). If the end of the film has been reached, the film is rewound (step P30). Return to Step P4. If it is determined in step P29 that the end of the film is not reached, the flow returns to step P4.

The details of the battery check process shown as steps P8 and P20 in the flowchart of FIG. 2 will be described with reference to the flowchart of FIG.

First, the flag BCL indicating the locked state of the camera and the flag BCW indicating the remaining battery warning display state are reset to 0 (steps P41 and P42). A signal is output to the switch circuit 18a, and a dummy load resistor RL is inserted between the terminals of the battery BAT (step P43). After waiting for a certain time until the voltage of the battery BAT is stabilized (step P44), the voltage between the terminals is A / D converted by the A / D converter 18b (step P45). Compare the A / D converted terminal voltage with the lock level reference voltage (step
P46) When the lock level is lower than the reference voltage, that is, when the remaining battery level is lower than the lock level, the flag BCL is set to 1 (step P47). When the voltage between the terminals is equal to or higher than the lock level reference voltage, that is, when the remaining battery level is equal to or higher than the lock level, the voltage is compared with the reference voltage of the warning level (step P48). Sets the flag BCW to 1 (step P49). When the terminal voltage is higher than the warning level reference voltage,
After the process of P49, the process proceeds to Step P50, where the switch circuit 18a
To disconnect the dummy load resistor RL from the terminals of the battery BAT. Check the flag BCL (step P51),
When the flag BCL = 1, the camera is locked (step P
52). When the flag BCL # 1, the flag BCW is checked (step P53). When the flag BCW # 1, the battery remaining amount warning display is turned off (step P54). When the flag BCW = 1, the battery remaining amount warning is displayed. The display is turned on (step P55), and the process returns to the main routine.

Details of the standby processing shown as step P19 in the flowchart of FIG. 2 will be described with reference to the flowchart of FIG. In order to reduce battery consumption, the camera of this embodiment has a WAIT mode and a STOP mode for temporarily stopping program processing in addition to a normal operation mode. In the STOP mode, the contents of the RAM are retained, but processing operations such as driving of the internal timer and the display device are stopped. In the WAIT mode, the driving of the internal timer and the display device is executed. The return from the STOP mode to the normal operation mode is executed by interrupting the control CPU 11 by the switch operation, and the return from the WAIT mode to the normal operation mode is timed by the internal timer in addition to the interrupt by the switch operation It is also executed by interrupting at predetermined time intervals.

In the flowchart of FIG. 4, first, an interrupt condition in the WAIT mode is set (step P61). Note that the internal timer is set to a predetermined time (for example, 250 ms), and an interrupt is made after the predetermined time has elapsed. By this processing, when any switch is operated, the operation mode can be immediately returned to the operation mode, and even if there is no switch operation, the operation mode can be returned after a predetermined time. Enable interrupt (step P62) and enter WAIT mode (step P6)
3). Here, if an interrupt occurs due to a switch operation or the end of counting of the internal timer, the process proceeds to an interrupt processing routine described later. Upon completion of the interrupt processing, the process proceeds to step P64 to disable the interrupt. After that, it is determined whether or not the cause of the return from the WAIT mode to the operation mode due to the end of time counting of the internal timer is determined by the state of the flag TM (step P65). 1, that is, when the counting of the internal timer is not completed, that is, when the switch operation is performed, the process immediately returns to the main routine, but when the counting of the internal timer is completed, the count value K of the counter that counts the number of times the internal timer has returned to the operation mode is set. Is added to (step P66). The count value K is reset after the operation of the camera is completed in step P4 of the flowchart shown in FIG. That is, the count value K corresponds to the elapsed time since the camera entered the standby state, and is indicated by K × (predetermined time set in the timer).

Proceeding to step P67, the state of the main switch SM is checked, and if it is ON, it is determined whether the value of K is equal to a predetermined value K1. Here, the predetermined value K1 is set to a value corresponding to the time required for the battery voltage to stabilize after the camera enters the standby state (for example, 10 seconds) (step P68). If K = K1, the state of the flag BCW is checked (step P69), and if BCW = 1, the battery check is executed again (step P7).
0). The battery check process is as described above with reference to the flowchart of FIG. The battery level warning display status is also updated, so if the battery voltage has recovered, the previously displayed battery level warning display will be turned off.If not, the battery level warning display will remain lit. Becomes

When the determination results in steps P67, P68, and P69 are negative, and after the processing in step P70, the process proceeds to step 71, where it is determined whether the value of K is equal to a predetermined value K2. Where the predetermined value
K2 is, for example, a value corresponding to one hour. If K = K2,
That is, for example, after the elapse of one hour, the display device is turned off regardless of the state of the main switch SM to prevent the battery from being consumed (step P72), and the mode automatically shifts to the STOP mode described below. This is called an auto power off function.

In the STOP mode, first, an interrupt permission condition for the STOP mode is set, the interrupt is permitted, and the STOP mode is entered (steps P73, P74, P75). When an interrupt is caused by the switch operation, the process proceeds to an interrupt processing routine described later. Upon completion of the interrupt process, the process proceeds to step P76, where the interrupt process is prohibited.
The state of the main switch SM is checked (step P77), and if it is ON, the display turned off by the auto power off function is turned on again (step P78), and the process returns to the main routine. If the flag TM ≠ 1 in the judgment of step P65, if K ≠ K2 in the judgment of step P71, and if SM is not ON in the judgment of step P78, the process returns to the main routine.

Details of the interrupt processing described in the flowchart of FIG. 4 in the WAIT mode in step P63 and the STOP mode in step P75 will be described with reference to the flowchart in FIG.

First, in step P91, the flag TM indicating that the interrupt is due to the timer is reset to 0, and the interrupt factor determination register (data is set in a specific register by the interrupt factor, which is executed by hardware)
To determine whether or not the content of the
P92). If the interrupt is caused by a timer, the flag TM is set to 1 (step P93), and the process returns to the main routine. If the interrupt is not caused by the timer, the process immediately returns to the main routine.

〔The invention's effect〕

As described above, according to the present invention, when the control state of the camera is in the operation mode, the battery check is repeatedly performed in the control operation processing, and a warning is displayed as necessary. When the control state of the camera is in the standby mode, a battery check is performed a predetermined time after the mode is shifted from the operation mode to the standby mode. Then, the warning display is updated and deleted in the standby mode.

In the standby mode, the period of the battery check can be lengthened, and the power is not unnecessarily consumed for the battery check.

[Brief description of the drawings]

FIG. 1 is a block diagram of a control circuit of a camera incorporating a battery check device of the present invention, and FIGS. 2 to 5 are flowcharts for explaining control processing executed by a control CPU. 11: control circuit CPU, 12: photometry circuit, 13: distance measurement circuit, 14: shutter drive mechanism, 15: flash unit, 16: film drive motor, 17: display device, 18: battery check circuit, 18a:
Switch circuit, 18b: A / D converter, BAT: battery.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03B 7/26 G03B 15/05

Claims (1)

(57) [Claims] 1. A camera provided with a camera control means having an operation mode in which a photographing operation and an operation related to photographing are being performed, and a standby mode in which the operation is terminated after the operation is completed and the operation is returned to the operation mode by the next switch operation. A battery check device for comparing a terminal voltage of the battery with a predetermined first reference voltage and a second reference voltage, wherein the terminal voltage of the battery is lower than the first reference voltage by the battery voltage determining device. Warning means for displaying a warning when it is determined that the voltage is higher than the reference voltage; prohibition means for prohibiting the control operation of the camera when the battery voltage determination means determines that the terminal voltage of the battery is lower than the second reference voltage; Mode determination means for determining whether the control state of the camera is in the operation mode or the standby mode, and the mode determination means When it is determined that the control state is in the operation mode, the battery voltage determination means is operated, and thereafter, when it is determined that the control state of the camera is in the standby mode, a predetermined time after the shift from the operation mode to the standby mode is performed. A battery check device for a camera, comprising: battery voltage discrimination control means for operating the battery voltage discrimination means after a lapse of time.