JP3370466B2 - Camera battery check device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery check device for a camera, which is suitable for checking the capacity (battery life) of a power supply battery of the camera.

[0002]

2. Description of the Related Art Conventionally, when checking the capacity of a battery such as a manganese battery or an alkaline battery, a dummy load having a constant resistance value is connected to these batteries to allow a current to flow, and after a specified time has passed, a dummy is loaded. A battery check device was used to measure the voltage appearing across the terminals of the load. Then, the size of the battery capacity is determined based on the level of this voltage.

However, a battery that has not been used for a long time, such as a new battery, may have a high internal resistance due to oxidation of internal substances. Therefore, if a current is flown in this state, a voltage drop occurs due to the internal resistance itself, the voltage appearing outside the battery is lowered, and a phenomenon that only a value below the specified voltage can be measured occurs.

Such an internal resistance is removed (activated) as a current is continuously passed through the battery. After being activated in this way, the voltage generated outside the battery also exhibits a value corresponding to the original capacity. Then, as the usage amount of the battery further increases, the voltage generated outside the battery corresponding to the decrease in the capacity also decreases.

Therefore, if the voltage generated between the dummy load terminals is simply measured, if the measured voltage is equal to or lower than the specified voltage, is the capacity sufficient but not activated? In the first place, it is impossible to judge whether the capacity is insufficient. That is, the measured voltage may not necessarily correspond to the capacity of the battery. This is the first problem in the prior art.

Further, in the conventional battery check device, the needed a dummy load for voltage measurement, there is a problem circuit parts of the entire battery check device number <br/> becomes. In this case, it is conceivable that the circuit component of the camera incorporating this battery check device may also be used as a load for voltage measurement. However, if the time for flowing the current from the power supply battery to this circuit component is long, the original of this circuit component The functions are unnecessarily exerted, so it is not possible to simply combine them. This is the second in the past
Is the problem.

[0007]

SUMMARY OF THE INVENTION The first object of the present invention is to solve the above-mentioned first problem in the prior art by measuring the voltage of the battery after the activation, and the battery voltage is measured. It is an object of the present invention to provide a battery check device for a camera capable of checking the capacity of a battery under a state corresponding to the capacity.

In view of the above-mentioned second problem of the prior art, the second object of the present invention is to use a circuit component having a separate original function as a dummy load for voltage measurement. it is to provide a battery check device of the camera never to waste exhibit the original function.

[0009]

The present invention adopts the following means in order to solve the above problems. That is, the first aspect of the camera battery check device according to the present invention is
A battery check device for a camera that measures the voltage generated between the terminals of the circuit component while allowing the current from the battery to flow through the circuit component that has the original function separately. At a time interval until the circuit component produces the original function, a switching unit that repeats the on / off of a current flowing through the circuit component, and the voltage is set every time a current is passed through the circuit component by the switching unit. The voltage measuring means for measuring, the first comparing means for comparing the voltage measured by the voltage measuring means with a predetermined reference voltage, and the first comparing means determines that the measured voltage is lower than the reference voltage. Counting means for counting the number of times,
When the count value by the counting means reaches a predetermined value,
As well as determine the voltage state of the battery as a first state of, prior before count value by the counting means to reach the predetermined value
Note that the first comparison means uses the measured voltage as the predetermined reference voltage.
When it is determined that the above is the case, a second comparison unit that determines the voltage state of the battery as the second state is provided (corresponding to claim 1).

According to a second aspect of the battery check device for a camera of the present invention, a circuit check closed circuit is constructed by connecting a circuit component having an original function and a battery to each other, and a terminal voltage of the circuit component. A battery check device for a camera that measures the voltage, comprising: switch means for connecting the circuit component and the battery to form the closed circuit for battery check; voltage measuring means for measuring the terminal voltage; The first comparing means for comparing the voltage measured by the means with a predetermined reference voltage, the switch means, the voltage measuring means, and the first comparing means until the circuit component exhibits the original function. together to perform a predetermined short time operation makes the unit measurement operation than the time of said first comparing means the measured voltage is lower than the predetermined reference voltage If it is determined, and control means for performing the unit measurement operation again, counting means said first comparing means for counting the number of times that the measured voltage is determined to lower than the reference voltage, the count value by the counting means before but when it reaches a predetermined value, while determining the voltage state of the battery as a first state of, where the counted value is reach the predetermined value
The first comparison means is configured such that the measured voltage is the predetermined reference value.
When it is determined that the voltage is equal to or higher than the voltage, a second comparison unit that determines the voltage state of the battery as the second state is provided (corresponding to claim 2).

Further, a third aspect of the Battery switch <br/> Ekku circuit of a camera according to the present invention, while supplying a current from the battery through a circuit component having separate original function, the circuit component terminals A battery check device for a camera, which measures a voltage generated between the circuit components, wherein the current flowing through the circuit components is intermittent at a time interval from when the current starts flowing through the circuit components until the circuit components perform the original function. Switching means, voltage measuring means for measuring the voltage every time a current is applied to the circuit component by the switching means, and the voltage measured by the voltage measuring means exceeds a certain reference voltage. A warning unit that gives a warning when the number of times of measurement reaches a predetermined number without any measure (corresponding to claim 4).

According to a fourth aspect of the battery checking device for a camera of the present invention, the voltage generated between the terminals of the circuit component is supplied while the current from the battery is passed through the circuit component having a separate original function. A battery check device for a camera to measure, a switch means that repeats the on / off of the current flowing through the circuit component at a time interval from when the current starts flowing through the circuit component until the circuit component produces the original function, Voltage measuring means for measuring the voltage every time a current is applied to the circuit component by the switching means, and the voltage measuring means before the number of times of measuring the voltage by the voltage measuring means reaches a predetermined number. And a photographing means capable of photographing only when the measured voltage exceeds a certain reference voltage (corresponding to claim 5).

[0013]

Embodiments of the present invention will be described below with reference to the drawings. Before giving a detailed description of each embodiment, the concept of each constituent element of the present invention will be described. (Switch Means) The switch means may be a switch having a mechanical contact or a transistor switch, as long as it has a function of interrupting a current flowing through a circuit component.

The switch means repeats the interruption of the current at a time interval from when the current starts flowing through the circuit component until the circuit component performs its original function. Therefore, the period during which the current flows depends on the circuit component. That is, if this is a circuit component that has an excellent response, the measurement time is hardly obtained.
On the contrary, for example, in the case of a circuit component having a reactance in its characteristic, it takes a long time to produce its original function due to the presence of a transient current, so that the measurement time can be relatively long. Further, even in the case of a circuit component whose state gradually changes, such as a bimetal element, it takes a long time to finally produce an original function, so that the measurement time can be relatively long. In addition, in the case of a lamp such as an incandescent lamp, it takes time until the temperature of the filament rises, in addition to the effect of the transient current, from when the current starts to flow to when the lamp is lit. Therefore, it is suitable for flowing the current from the battery (corresponding to claims 8 and 9). As this lamp, a red-eye preventing lamp used for stroboscopic photography can be used (corresponding to claim 10).

Further, the switch means is constructed so that, when the count value by the counting means reaches a predetermined value, the flow of the current to the circuit parts thereafter is interrupted and the interruption is not repeated. Is also good. By doing so, it is possible to prevent wasteful consumption of current. (Voltage Measuring Means) The voltage measuring means may directly measure the terminal voltage of the circuit component, or may convert it into another unit and measure it. For example, the voltage measuring means is composed of an integrating circuit composed of a resistor and a capacitor connected in parallel to the circuit component, and a time measuring means for measuring the time until the voltage generated between the terminals of the capacitor reaches a predetermined value. It may be configured. In this case, the voltage generated between the terminals of the circuit component can be indirectly measured based on the length of the measured time (corresponding to claim 6).

When the time measuring means measures time, it may be compared with a reference value. To do so, the voltage measuring means is provided with a constant voltage source for generating the reference voltage, and when the reference voltage is applied to the capacitor, the voltage generated between the terminals of the capacitor reaches the predetermined value. Can be configured to be measured by the time measuring means with the time until the reference time as a reference time, and the time measured based on the voltage generated between the terminals of the circuit component is compared with the reference time (claim) 7). With this configuration, for example, even when the capacitor deteriorates and the capacitance changes, an appropriate reference value can be obtained. (Warning Means) The warning means may visually warn,
You may give an audible warning. For example, a light emitting element, particularly a light emitting diode, may be provided in the viewfinder of the camera to emit light.

[0017]

First Embodiment A first embodiment of the present invention will be described below with reference to the drawings. This embodiment shows an example in which the battery check device for a camera according to the present invention is mounted on a compact camera with a built-in strobe (hereinafter, simply referred to as "camera"). <Appearance of Camera> FIG. 2 is a perspective view showing the appearance of the camera 1. As is apparent from FIG. 2, on the front surface of the camera 1, there are a photographing lens 2, a stroboscopic light emitting window 3, a red-eye prevention lamp 4, a distance measuring window 8, a photometric window 9, and a viewfinder window 1.
0 is provided. Among these, the red-eye prevention lamp 4 is a lamp that closes the iris of the person to be photographed by turning on the light immediately before strobe light emission in order to prevent the subject's red-eye phenomenon during stroboscopic photography.

Further, on the upper surface of the camera 1 (the upper surface in FIG. 2), a main switch 6 for turning on the power to the circuit of the camera is provided with a shutter over button 5. Further, inside the camera 1, an AA alkaline battery or a manganese battery (hereinafter, simply referred to as “battery”) 7 is provided.
The book is built in so that it can be replaced. <Structure of Automatic Exposure Control Circuit of Camera Internal Circuit> FIG. 1 is an internal circuit of the camera 1 described above. The microcontroller 11 in FIG. 1 is a microcomputer for controlling the entire camera 1. This microcontroller 11 has functions as a control means, a switch means, a voltage measuring means (time measuring means), a first comparing means, a counting means, a second comparing means, a photographing means, and a warning means. .

The negative electrode of the power supply 7 is connected to the GND port of the microcontroller 11 and is supplied with the ground potential. Hereinafter, the portion connected to the GND port and supplied with the ground potential will be referred to as GND.

A regulator 17 is connected to the positive electrode of the battery 7 via a diode D1 connected in the forward direction. The regulator 17 is a constant voltage circuit that supplies a power supply voltage (VDD) to the VDD port of the microcontroller 11. Here, the power supply voltage (VDD)
Is 2V. Note that V of the microcontroller 11
Between the DD port and GND, a capacitor C2 which power supply voltage from the regulator 17 (VDD) is marked pressure is connected. This capacitor C2 is connected to the power supply voltage (VD
It is for backup of D). That is, the voltage of the battery 7 falls below the operating voltage of the regulator 17, and the regulator 1
If the 7 2V power supply voltage (VDD) is Tsu or such output from, to discharge electrification that has accumulated, it is to ensure the operation of the microcontroller 11. Diode D
1 is to prevent the reverse flow of current when the capacitor C2 is discharged.

On the other hand, the above-mentioned red-eye prevention lamp 4 is connected to the positive electrode of the battery 7. A switching transistor 16 as switching means is connected in series between the other end of the red-eye prevention lamp 4 and GND. The base of the switching transistor 16 is connected to the LMP _ OUT port of the microcontroller 11, ON / OF This microcontroller 11
F controlled.

Further, the series resistances R2 and R1 connected to the P101 port of the microcontroller 11 are connected to the battery 7 side terminal of the red-eye prevention lamp 4. The resistance value of the resistor R2 is sufficiently smaller than the resistance value of the resistor R1. Connection point A of these resistors R2 and R1
And GND between these resistors R1 and R2, a capacitor C forming an integrating circuit as a voltage measuring means.
1 is connected. The positive terminal of the capacitor C1 is also connected to the P102 port of the microcontroller 11.

Both electrodes of the battery 7 are connected to V of the strobe circuit 12.
It is also connected between the BATT port and the GND port to supply power to this strobe circuit 12. The CHEN port of the strobe circuit 12 is connected to the CHEN port of the microcontroller 11 and receives a charge start signal from the microcontroller 11. The RLS port of the strobe circuit 12 is connected to the microcontroller 11
Connected to the RLS port of the microcontroller 11
Send a charge complete signal to. Further, the STRG port of the strobe circuit 12 is the STR of the microcontroller 11.
It is connected to the G port and receives a strobe trigger signal from the microcontroller 11.

[0024] The scan Toro volume circuit 12, a strobe light emitter disposed within the flash window 3, the booster circuit, and a charging capacitor, and the like. When receiving the charging start signal, starts charging of the charging capacitor, when charging is completed, transmits the charge completion signal, when receiving a strobe trigger signal is performed strobe emission of the strobe light emitter.

The P1 port of the microcontroller 11 is a photometry circuit 1 for measuring the subject brightness through the photometry window 9.
3 to receive photometric data from the photometric circuit 13.

Similarly, P2 of the microcontroller 11
The port is connected to a distance measuring circuit 14 that measures a subject distance through the distance measuring window 8 and receives distance measuring data by the distance measuring circuit 14.

Similarly, P3 of the microcontroller 11
Port is connected to the shutter over the drive circuit 15 for driving the shutter over and the focusing lens in the photographing lens 2, transmits an operation signal to the shutter over the drive circuit 15.

Similarly, P4 of the microcontroller 11
The port is connected to a winding motor drive circuit 20 for driving a motor for winding the film,
An operation signal is transmitted to the winding motor drive circuit 20.

A light emitting diode LED as a warning means provided in the finder window 10 is connected between the P5 port of the microcontroller 11 and the GND, and blinking control is possible by the P5 port.

The main switch 16 is connected to the MAIN port of the microcontroller 11, and the state of the main switch 16 is input. Similarly, a photometric switch 18 is connected to the SWS port, and a release switch 19 is connected to the SWR port, and their states are input. This photometric switch 18 is used for the shutter button 5
The release switch 19 corresponds to the second stage of the shutter button 5.

FIG. 3 shows an integrating circuit (resistor R
1, R2, and capacitor C1) in detail. VBATT in FIG. 3 is the positive electrode of the battery 7 and the red-eye prevention lamp 4
It is the potential that appears between and. This VBATT is battery 7
Of the red-eye prevention lamp 4 and the presence or absence of a current flowing in the red-eye prevention lamp 4. Since the battery 7 is formed by connecting two AA batteries in series, if the battery 7 is new and almost no current flows, VBATT = 3 (V).

The P101 port of the microcontroller 11 is a port for both input and output, and as shown in FIG.
The H state of outputting VDD (2V) and the state of the input mode are switched. Here, when the P101 port is viewed from the outside in the input mode, it is in a high impedance state. Similarly, the P102 port is also an input / output port, and switches the L state for outputting the ground potential, the H state for outputting VDD (2V), and the input mode state, as shown in FIG. The terminal voltage of the capacitor C1 is read from this P102 port in the input mode. <Processing Flow in Microcontroller> Next, based on the time chart of FIG. 4 and the flowcharts of FIGS. 5 and 6, the processing executed in the microcontroller 11 to which each electronic component is connected as described above will be described. explain.

The automatic exposure control process shown in FIG.
It starts when the battery is stored inside, when the main switch 6 is turned on in the standby state, and so on. Then, the state of the main switch 6 is first checked (step S1
01), if ON, the state of the photometric switch 18 is checked (step S102). If the main switch 6 is off in step S101, the camera is set to the standby state. The standby state is a state in which only the minimum current capable of recognizing the state of the main switch 16 is supplied to the microcontroller 11 while maintaining the memory state of the memory in the microcontroller 11. If the photometric switch 18 is off in step S102, the process returns to step S101.

On the other hand, when the photometric switch 18 is ON in step S102, step S103
Execute the battery check process of. FIG. 6 shows a subroutine of this battery check process.

In the first step S201 after entering this subroutine, the count value S = 1 of the number of battery checks is first set. Next, the loop of the unit measurement operation of steps S202 to S210 is executed. That is, in step S202, the P101 port is set to the input mode and the P102 port is set to the L output state. As a result, the charge accumulated in the capacitor C1 is cleared through the P102 port.

At the next step 203, the switching transistor 16 is turned on to supply a current to the red-eye prevention lamp 4 (corresponding to a switch means). In step S204, which is executed immediately after execution of step S203, the resistance R
1. Measure the time constant of the capacitor C1. In particular,
Capacitor C1 after P102 port is in input mode
The time (T1) until the terminal voltage of reaches the reference value Vc is measured (corresponding to the voltage measuring means (time measuring means)).

That is, when the P102 port is set to the input mode, when the capacitor C1 is determined by VBATT and the value of the resistor R1 and the value of the capacitor C1 while the current is flowing through the red-eye prevention lamp 4 (dummy load). According to the constant, the electric charge is accumulated. At this time, since the P101 port remains in the input mode,
The influence of the current flowing through the resistor R2 can be ignored. This relationship is expressed by the following equation (1).

[0038]

[Equation 1]

However, in this embodiment, the capacitor C
The value of 1 is 0.022 μF, and the value of the resistor R1 is 510
It is kΩ. As is clear from the equation (1), the time (T1) changes according to the value of VBATT. Therefore,
The value of VBATT can be indirectly known by measuring the time (T1). When the measurement of T1 is completed, the P102 port is immediately set to the L output state to clear the charge accumulated in the capacitor C1.

The value of the reference value Vc is calculated and set so that T1 is within the time from when the switching transistor 16 is turned on to when the red-eye prevention lamp 4 is actually turned on. The details will be described with reference to Table 1. In this table 1, the switching transistor 16 is
The time from when it is set to N until it is visually recognized that the red-eye prevention lamp 4 is actually turned on is experimentally obtained and shown for each VBATT.

[0041]

[Table 1]

When the impedance Z of the red-eye prevention lamp 4 is 4.2Ω (when the wattage of the red-eye prevention lamp 4 is 1.5 W), for example, VBATT = 1.7.
When it is set to [V], it can be identified from Table 1 that the red-eye prevention lamp 4 is turned on about 29 ms after the switching transistor 16 is turned on. Therefore, if the reference value Vc is set to 1.5 V or less, T1 = 2 in the formula (1) even when the judgment reference voltage of VBATT is 1.7 V.
Since it is 4 ms, it is possible to prevent the lighting of the red-eye prevention lamp 4 from being visually recognized during the T1 measurement. However, when VBATT greatly falls below the judgment reference voltage, T1 may exceed the lighting point of the red-eye prevention lamp 4 in calculation. However, for such cases, V
When the state of BATT is equal to the reference value Vc, the time until it can be recognized that the red-eye lamp 4 is turned on is set as the maximum measurement time of T1, and when this time is reached, the switching transistor 16 is turned off, and the T1 is turned off. The measurement should be stopped. As described above, in this embodiment, Vc = 1
/ 2 · VDD = 1V, that is, Vc is set by using the threshold level of the port. V in equation (1)
Table 1 shows the calculated value of T1 when c = 1 [V].

In step S205, which is executed immediately after execution of step S204, the switching transistor 16 is turned off (corresponding to the switching means). Therefore,
As described above, the red-eye prevention lamp 4 is prevented from turning on.

In the next step S206, the P101 port is set to the H output state. Therefore, this condition, P 101
It can be considered that a constant voltage source that outputs VDD (2 V) as a reference voltage is connected to the end of the port .

At the next step S207, resistors R1 and R
2. Measure the time constant of the capacitor C1. In particular,
Capacitor C1 after P102 port is in input mode
The time (T2) until the terminal voltage of V reaches Vc is measured.

That is, when the P102 port is set to the input mode, VBATT and VDD in the state where no current is flowing to the red-eye prevention lamp 4 (dummy load), the combined resistance of the resistors R1 and R2, and the capacitor C1 The charge is accumulated according to the time constant determined by the value of the capacitor C1. This relationship is expressed by the following equation (2).
Represented by

[0047]

[Equation 2]

By the way, as described above, the value of R2 is R
It is set to be sufficiently smaller than 1. Therefore, the part of R2 / (R1 + R2) · VBATT in the equation (2) can be approximated to zero. That is, VBA for T2
The effect of TT can be ignored. for that reason,
An almost constant reference time (T2) can be obtained regardless of the value of VBATT. Immediately after the measurement of T2 is completed, the P102 port is set to the H output state. This is to prevent the latch-up phenomenon from occurring due to the voltage from the battery 7 being applied to the inside of the microcontroller 11.

In the next step S208, the measured T
Calculation based on 1, T2 is performed. That is, T with respect to T2
The ratio of 1 (T1 / T2) is calculated. Next step S209
Then, based on the calculation result obtained in step S208,
Determine the result of the battery check. In particular,
It is checked whether the following formula (3) is satisfied (first
Corresponding to the comparison means).

T1 / T2 ≧ a (3) Here, for example, 6 is set as the value of a. In this way, the length of T1 can be identified with reference to T2, which is a substantially constant value.

When T1 / T2 is equal to or greater than a, it is determined that VBATT has not reached the determination reference voltage.
Wait 20 ms in step S210. This is because if heat remains in the filament of the red-eye prevention lamp 4, the time required for relighting becomes short, so the filament of the red-eye prevention lamp 4 is cooled in preparation for the T1 measurement (step S204) in the next loop. This is because. Then, after 20 ms has elapsed, the process proceeds to step S211.

In this step S211, step S2
Number of battery checks performed in 09 (S)
It is checked whether the number has reached 8 times (corresponding to counting means). If it has not reached eight times yet, the count value S is incremented by 1 in step S212, the process is returned to step S202, and the battery check is executed again. The number of battery checks (S = 8) at the time of exiting the loop in step S211 may be another number, but by setting it to 8 (times), the activation can be almost performed. Further, for example, the number of battery checks may be changed according to the environmental temperature.

On the other hand, when the number of battery checks reaches 8 without T1 / T2 becoming less than a, it can be determined that the capacity of the battery 7 is insufficient. Therefore, this loop is exited from step S211. Then, in the next step S213, the state of the photometric switch 18 is checked, and the photometric switch 18 is turned off.
As long as it is N, the light emitting diode LED provided in the viewfinder blinks to continue to warn the photographer (corresponding to the warning means). If the photometric switch 18 is turned off during that time, the process returns to step S101.

On the other hand, as a result of repeating the above battery check, when it is determined in step S209 that the battery 7 is activated, VBATT reaches the determination reference voltage, and T1 / T2 becomes less than a, This battery check subroutine is terminated, and the process returns to the main routine of FIG. 5 (corresponding to the photographing means). That is, step S
209 and step S211 correspond to the second comparing means, and when S = 8 is reached, VBATT determines the first state (a state corresponding to the case where the capacity of the battery 7 is not sufficient), and sets S = 8. When the loop is exited from step S209 before reaching, it is determined that VBATT is in the second state (a state corresponding to the case where the battery 7 has a sufficient capacity).

In the main routine to which the processing is returned, in step S104 following step S103, photometry is performed. That is, the output of the photometric circuit 13 is read. In the next step S105, the distance measuring circuit 14 is activated to read the distance measuring data of the subject.

In the next step S106, the state of the photometric switch 18 is reconfirmed. If the photometric switch 18 is off, the process returns to step S101, but on.
If so, the state of the release switch 19 is checked in step S107. This release switch 1
If 9 is still OFF, the process proceeds to step S106.
Return to.

On the other hand, the release switch 19 is turned off.
If the result is N, the process proceeds to step S108. In step S108, the shutter over the drive circuit 1
5 Start, on the basis of distance data obtained by the photometric data and the step S105 obtained in step S104, a predetermined aperture value, a shutter over speed, and at the focus position, and performs exposure of the film.

When the exposure of the film is completed, in the next step S109, the winding motor drive circuit 20 is activated to wind the film by one frame. Next step S
In 110, the photometric switch 18 and the release switch 1
Waiting for both 9 to be turned off, and when both are turned off, the process is returned to step S101. <Operation of Embodiment> According to the camera of the present embodiment configured as described above, as a result of repeatedly executing the loop processing (battery check, unit measurement operation) of steps S202 to S211 in FIG. 6, FIG. As shown in (a), LMP
The output signal of the _OUT port is interrupted in a pulse shape. So
For switching the switching transistor 16
By the operation , the current (lamp current) flowing through the red-eye prevention lamp 4 as a dummy load is also interrupted. Then, T1 based on VBATT is measured during the period when the current is flowing through the red-eye prevention lamp 4, and T2 based on VDD is measured at each period when the current is not flowing through the red-eye prevention lamp 4.

At this time, the length of the period in which the current is applied to the red-eye prevention lamp 4 is longer than the time from when the current is applied to the red-eye prevention lamp 4 until when the red-eye prevention lamp 4 is actually illuminated and can be visually identified. Is also set short. Therefore, the circuit component (red-eye prevention lamp 4) having the original function (light emission for red-eye prevention) is also used as the dummy load used when measuring the capacity of the battery 7, and the number of circuit components is reduced. Before the circuit component (red-eye prevention lamp 4) exhibits its original function, the current flowing through the circuit component (red-eye prevention lamp 4) is stopped. Therefore, this circuit component (red-eye prevention lamp 4) can be prevented from unnecessarily exhibiting its unique use. That is, it is possible to prevent the red-eye prevention lamp 4 from emitting light without being originally necessary to make it look bad.

When such a loop process (battery check) is repeatedly executed to supply a current to the red-eye prevention lamp 4, even the battery before activation is gradually activated, and FIG. As shown, the integration circuit (resistors R1,
R2, voltage measured by capacitor C1) (VB
ATT) also gradually rises to show a value corresponding to the original capacity. As a result, this voltage (VBAT
If it can be confirmed that T) has reached the determination reference voltage, it can be determined that the battery 7 has a sufficient capacity, and thus normal shooting processing is possible.

On the other hand, even if the loop processing (battery check) is repeated eight times, the voltage between terminals (VBATT)
If does not reach the judgment reference voltage, it can be considered that the battery 7 has been used and no sufficient capacity remains. Therefore, further loop processing (battery check) is useless, so it is possible to terminate this, issue a warning, and prohibit photographing.

[0062]

According to the battery check device for a camera according to the present invention constructed as described above, by measuring the voltage of the battery after the activation, the battery voltage is measured under the condition corresponding to the battery capacity. , You can check the battery capacity. Further, even when a circuit component having another original function is also used as a dummy load for voltage measurement, voltage measurement can be performed without wastefully exerting the original function of this circuit component.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an internal circuit of a camera equipped with a battery check device for a camera according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing the appearance of the camera in FIG.

FIG. 3 is a detailed diagram of the integrating circuit in FIG.

[4] P101 port in FIG. 3, P102 port, and LMP _ OUT port time chart showing a signal state of

5 is a flowchart showing the contents of control processing executed in the microcontroller of FIG.

6 is a flowchart showing the contents of a battery check subroutine executed in step S103 of FIG.

FIG. 7 is a time chart showing states of output signals and terminal voltages of the LMP_OUT port .

[Explanation of symbols]

1 camera 4 Red-eye prevention lamp 7 batteries 11 Micro controller 16 switching transistors R1 resistance R2 resistance C1 capacitor LED light emitting diode

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01R 31/36 G01R 19/00-19/32 G03B 7/26

Claims (10)

(57) [Claims] 1. A battery check device for a camera, which measures a voltage generated between terminals of a circuit component while allowing a current from a battery to flow through the circuit component having a separate original function. Switch means for repeating the intermittent flow of the current flowing through the circuit component at a time interval from when the current starts to flow until the circuit component performs the original function, and while the current is being passed through the circuit component by the switch means. Voltage measuring means for measuring the voltage for each time; first comparing means for comparing the measured voltage by the voltage measuring means with a predetermined reference voltage; and the first comparing means for measuring the measured voltage from the reference voltage. And counting means for counting the number of times determined to be low, when the count value by the counting means reaches a predetermined value,
As well as determine the voltage state of the battery as a first state of, prior before count value by the counting means to reach the predetermined value
Note that the first comparison means uses the measured voltage as the predetermined reference voltage.
A battery checking device for a camera, comprising: a second comparing unit that determines the voltage state of the battery as a second state when the determination is made as above. 2. A battery check device for a camera, wherein a battery check closed circuit is constructed by connecting a circuit component having a separate original function and a battery to each other to measure a terminal voltage of the circuit component. Switch means for connecting the battery and the battery to form the battery check closed circuit; voltage measuring means for measuring the terminal voltage; and first comparing voltage measured by the voltage measuring means with a predetermined reference voltage. And the switch means, the voltage measuring means, and the first comparing means perform a unit measurement operation in which the circuit component is operated for a predetermined time shorter than the time until the circuit component exerts its original function. together, if the first comparison means the measured voltage is determined to lower than the predetermined reference voltage, and a control means for executing said unit measurement operation again, before Counting means for the first comparison means for counting the number of times that the measured voltage is determined to lower than the reference voltage, when the count value by the counting means reaches a predetermined value,
As well as determine the voltage state of the battery as a first state of said first comparison hands before the counted value is reach the predetermined value
Stage determines that the measured voltage is greater than or equal to the predetermined reference voltage.
In other cases, the battery check device for a camera is provided with a second comparing unit that determines the voltage state of the battery as a second state. 3. The second state is a voltage state corresponding to a case where the battery has a capacity necessary to drive the camera, and the first state is a state where the battery drives the camera. The battery check device for a camera according to claim 1 or 2, wherein the battery is in a voltage state corresponding to a case where the battery does not have a required capacity. 4. A battery check device for a camera, which measures a voltage generated between terminals of a circuit component while allowing a current from a battery to flow through the circuit component having an original function separately, Switch means for repeating the intermittent flow of the current flowing through the circuit component at a time interval from when the current starts to flow until the circuit component performs the original function, and while the current is being passed through the circuit component by the switch means. Voltage measuring means for measuring the voltage for each, and a warning means for issuing a warning when the number of measurements reaches a predetermined number without the voltage measured by the voltage measuring means exceeding a certain reference voltage. A battery check device for the camera, which is equipped with. 5. A battery check device for a camera, which measures a voltage generated between terminals of a circuit component while allowing a current from a battery to flow through the circuit component having a separate original function. Switch means for repeating the intermittent flow of the current flowing through the circuit component at a time interval from when the current starts to flow until the circuit component performs the original function, and while the current is being passed through the circuit component by the switch means. Voltage measuring means for measuring the voltage every time, when the voltage measured by the voltage measuring means exceeds a certain reference voltage before the number of times of measuring the voltage by the voltage measuring means reaches a predetermined number of times. A battery check device for a camera, comprising: a photographing means capable of photographing only. 6. The time for measuring the time required for the voltage measuring means to reach a predetermined value for the voltage generated between the integrating circuit including a resistor and a capacitor connected in parallel to the circuit component and the terminal of the capacitor. 2. A measuring unit, which measures the voltage generated between the terminals of the circuit component based on the length of the measured time.
The battery check device according to any one of 2, 4, and 5. 7. The voltage measuring means further comprises a constant voltage source for outputting the reference voltage, and a voltage generated between terminals of the capacitor when the reference voltage is applied to the capacitor is equal to the predetermined value. 7. The time until reaching the reference time is measured by the time measuring means, and the reference time is compared with the time measured based on the voltage generated between the terminals of the circuit component. Battery check device. 8. The circuit component is a lamp, and the switch means connects and disconnects the current at a time interval shorter than the time from when the current starts to flow to the lamp until the lamp is turned on. Claims 1, 4,
Or the battery check device according to any one of 5 above. 9. The circuit component is a lamp, and the switch means connects the lamp and the battery at a time interval shorter than a time from when current starts flowing to the lamp to when the lamp is turned on. The battery check device according to claim 2, wherein the battery check device forms a closed circuit. 10. The lamp is a red-eye prevention lamp,
10. The battery check device according to claim 8, wherein the switch means also functions as a lighting switch for the red-eye prevention lamp.