JP2001083580A - Exposure control driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease a voltage drop of a battery and prolong its life by making a shutter operate by electric charges accumulated in a capacitor pre-charged by a stroboscopic voltage boosting circuit. SOLUTION: A CPU 1 supplies image pickup light to CCD in CCD 4 for an electric charge accumulating time to be set based on brightness of an object detected by AE 2 after having discharged electric charges presently accumulated in the CCD in the CCD 4. When the preset electric charge accumulating time has elapsed, the CPU 1 outputs a charging signal SMt so that the electric charges can be taken out of a shutter capacitor CMT, and then outputs pulses to a terminal Ms to drive a motor coil L12 and closes the shutter served also as diaphragm. Then, the charged voltage of the shutter capacitor CMT is supplied to the motor coil L12 via a regulator REG 2. Namely, no current is made to flow through the motor M from the battery E when the motor for driving the shutter served also as diaphragm is driven.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to an exposure control driving device.

2. Description of the Related Art Conventionally, an actuator (motor or the like) for driving an exposure control member such as a shutter or an aperture is
As shown in FIG. 7, it is driven using a battery power supply via a regulator. FIG. 7 shows a configuration of a conventional digital still camera. Referring to FIG.
1 is a control circuit (hereinafter referred to as “CPU”) 10, a photometric circuit (hereinafter referred to as “AE”) 2, and a distance measuring circuit (hereinafter referred to as “A”).
F ". 3, an image pickup unit (hereinafter, referred to as "CCD") including a CCD as an image pickup element, a CCD drive circuit, a video signal processing circuit, a drive voltage generation circuit, and the like.
A battery E is provided in an electronic viewfinder (hereinafter referred to as "LCD") 5 including a liquid crystal panel for displaying an image captured by the CD 4, a liquid crystal panel driving circuit, a driving voltage generating circuit, and the like.
Voltage is supplied stably. The CPU 10 is a CPU, an RO
M, RAM, etc., and controls various operations according to operation programs stored in the ROM. The booster circuit (hereinafter, referred to as “CG”) 6 operates in response to a charge start signal STc output from the CPU 10, boosts the voltage of the battery E to, for example, about 350 V, and charges the strobe capacitor CST via the diode D101. A strobe drive circuit (hereinafter, referred to as "STB") 7 is operated by a strobe trigger signal STt output from the CPU 10, and applies a charging voltage of a strobe capacitor CST to the xenon tube Xe to emit strobe light. The STB 7 causes the xenon tube Xe to fully emit light upon input of the strobe trigger signal STt (hereinafter referred to as “STBa”), and the STB 7 causes the xenon tube Xe to emit light only while the strobe trigger signal STt is being output (hereinafter “STBa”). STBb ")
And are appropriately selected and used. The motor driver MDR101 includes transistors Tr101 to Tr10.
4. A current in a desired direction is applied to a motor coil L101 in a motor M101 for driving an exposure control member such as a shutter and an aperture, which includes resistors R101 to R104 and the like. The current supplied to the motor coil L101 is supplied from the battery E via the regulator REG102. The voltage detection circuit VDT0 detects the voltage of the battery E, and generates a dead battery detection output when the voltage of the battery E approaches the minimum operation guarantee voltage of the CPU 10. The CPU 10 issues a battery exhaustion warning on the display unit DSP in response to the battery exhaustion detection output, or disables a release switch (not shown) to prevent the shutter from being exhausted. The voltage detection circuit VDT1 detects the charging voltage of the strobe capacitor CST, and when the charging voltage is lower than the strobe light emission minimum drive voltage Vth3, the detection signal ST
fa and the charging voltage is the strobe emission minimum drive voltage V
When the charge voltage is higher than th3 and lower than the charge completion level voltage Vmax2, a strobe operable signal STfb is output, and when the charge voltage reaches the charge completion level voltage Vmax2, a charge completion signal STfc is output. The display means DSP displays a battery exhaustion warning or the like.

In general, a control circuit such as a CPU malfunctions or becomes inoperable when the power supply voltage decreases. However, when a battery is used as a power supply, the battery voltage is reduced by the internal resistance of the battery. The larger the value, the lower the value. In the example of FIG. 7, the CPU 10
In order to avoid the operation failure, the voltage of the battery E is monitored by the voltage detection circuit VDT0, and when the battery voltage approaches the minimum operation guarantee voltage of the CPU 10, a battery exhaustion warning is displayed or the shutter is not released. That is, when the battery voltage approaches the minimum operation guaranteed voltage of the CPU 10, it is determined that the battery is exhausted. In a device having such a battery voltage monitoring function, due to current consumption flowing in a circuit that operates temporarily, that is, due to a temporary increase in current consumption, even though there is still room in the battery capacity, In some cases, the battery voltage easily approaches the minimum operation guarantee voltage of the CPU, and it is determined that the battery has run out. In particular, many digital still cameras are equipped with an imaging unit such as a CCD powered by a battery or an electronic viewfinder including a liquid crystal panel.
In particular, there is a case where the operation is performed when deciding the composition. When the shutter or the like is driven in this state, the current consumption increases temporarily, so that the erroneous determination is highly likely to occur. Recently,
In digital still cameras, to avoid the above disadvantages,
For example, at the time of strobe charging, the operation of the liquid crystal panel of the electronic viewfinder is stopped, for example, so that a plurality of circuits and the like are simultaneously driven as much as possible to reduce the peak current value of the battery E. However, even if various circuits and the like are not simultaneously driven as much as possible, there are some which must be simultaneously driven mechanically. In such a case, the peak current of the battery E naturally becomes large, and only a short time has passed since the start of use. Even if the battery is not used, there is a problem that it is determined that the battery is exhausted.

According to the present invention, there is provided a booster circuit for boosting a battery voltage, a first capacitor charged via the booster circuit, and a strobe light emitting unit which operates using the first capacitor as a power supply. And a second capacitor that is charged via the booster circuit, and an actuator that drives the exposure control member using the second capacitor as a power supply, so that the operation of the actuator that drives the exposure control member , The battery voltage can be prevented from dropping.
Further, since the first capacitor for strobe light emission and the second capacitor for driving the actuator are charged by one booster circuit, the configuration can be simplified. Also, a first condenser for strobe light emission and a second condenser for driving the actuator are provided.
The power supply for strobe light emission and the power supply for driving the actuator are independent from each other, and the respective operations do not affect each other's power supply voltage fluctuation, and the respective operations can be stabilized. If a charging / discharging circuit is provided for each of the first capacitor and the second capacitor, and these charging / discharging circuits are operated independently, the degree of freedom in the timing of charging / discharging each is improved. If the first capacitor and the second capacitor are charged alternately, the peak current of the battery can be reduced as compared with the case of charging at the same time. If a switch circuit for connecting the first capacitor and the second capacitor in parallel is further provided, the two capacitors can be integrated as one power supply. For example, when the charging voltage of one capacitor decreases, the charging voltage of the other capacitor can be supplied to one capacitor. When the strobe non-use mode is designated, if only the second capacitor for the actuator is charged out of the first capacitor and the second capacitor, the unnecessary first capacitor is charged by the battery. Can be avoided, and the battery life can be extended. If charging of the first capacitor and the second capacitor is prohibited during the photographing operation, the charging operation and the photographing operation can be performed at different timings, and an increase in the peak current of the battery can be suppressed. A booster circuit for boosting the battery voltage, a capacitor charged through the booster circuit, and an actuator for driving the exposure control member using the capacitor as a power source, so that the actuator for driving the exposure control member It is possible to prevent the battery voltage from dropping during operation. Preferably, the exposure control member is a camera shutter member or a camera aperture member. A voltage detection circuit that detects a state where the voltage of the battery is equal to or lower than a predetermined value, a control circuit that operates using the battery as a power source, controls the operation of the actuator, and has a minimum operation guarantee voltage smaller than the predetermined value; When the voltage detection circuit detects a voltage equal to or less than the predetermined value, a determination unit that determines that the battery is dead can be further provided, so that the battery voltage can be prevented from dropping due to the operation of the actuator that drives the exposure control member. In addition, it is possible to reduce the problem that even a battery that has been used for a short time has been determined to be "battery exhausted".

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to an embodiment shown in the drawings. FIG. 1 shows an example in which the present invention is applied to a digital still camera. In the figure, the same components as those in FIG.
The strobe capacitor CST forms a first capacitor. In FIG. 1, a control circuit (hereinafter, referred to as “CPU”) 1 includes a CPU, a ROM, a RAM, and the like.
Various operations are controlled in accordance with the operation program stored in M. In this example, a motor M is employed as an example of the actuator. The drive circuit MDR1 includes transistors TR1 and TR2, resistors R1 and R2, and protection diodes D1 and D2, and the motor coils L11 and L12.
To drive a motor M that drives an exposure control member A described later. The winding directions of the motor coils L11 and L12 are reversed, and when the transistor TR1 and the transistor TR2 are selectively turned on, a reverse magnetic force is generated. One ends of the motor coils L11 and L12 are connected to a terminal a, and the terminal a is connected to a regulator REG2 as a constant current element. Regulator REG
2 is a shutter capacitor C as a second capacitor
The MT charging voltage is input, and a constant current is supplied to the terminal a.
Since the charging voltage of the shutter capacitor CMT is supplied to the motor M via the regulator REG2 (constant current element) in this manner, the motor M can be driven with a constant current, and the charge charged in the shutter capacitor CMT can be used effectively. One end of the shutter capacitor CMT is connected to the collector of the transistor TR4 as a charge / discharge circuit,
The emitter of R4 is connected to the low potential side of the power supply, and the base of the transistor TR4 is connected to the CPU 1 via a resistor R4.
Receives a charging signal SMt. A diode D3 and a switch circuit S are connected to the other end of the shutter capacitor CMT.
C1 is connected, and the output of CG6 and the charging voltage of the strobe capacitor CST are supplied through these, and the shutter capacitor CMT is charged by these outputs.
The voltage detection circuit VDT2 detects the charging voltage of the shutter capacitor CMT, and determines that the charging voltage is the lowest driving voltage V of the motor M.
When the charging voltage is lower than th1, the detection signal SHfa is output. When the charging voltage is higher than the minimum drive voltage Vth1 of the motor M and lower than the charging completion level voltage Vmax, the motor operable signal SHfb is output, and the charging voltage is changed to the charging completion level voltage. When the voltage reaches Vmax, a charge completion signal SHfc is output.
The switch circuit SC1 includes transistors TR5, TR6 and resistors R5, R6, R7, etc., is turned on by the input of the parallel connection signal PAL from the CPU 1, and connects the strobe capacitor CST and the shutter capacitor CMT in parallel. The collector of the transistor TR3 as a charging / discharging circuit is connected to a terminal on the opposite side of the terminal of the strobe capacitor CST connected to the diode D101. The emitter of the transistor TR3 is connected to the low potential side of the power supply. C on the base via resistor 3
The charging signal SSt is input from PU1. Since a large current for strobe light flows through the transistor TR3, I
GBT (Insulated Gate Bipola)
r Transistor) is used. As described above, each of the first capacitor (strobe capacitor CST) and the second capacitor (shutter capacitor CMT) has a charge / discharge circuit (transistor T
R3, TR4), and these charge / discharge circuits can operate independently, so that the degree of freedom of each charge / discharge timing is improved. FIG. 2 shows the motor M and the exposure control member A. In this example, an aperture / shutter is used as the exposure control member A. In the figure, a motor M is a rotor R,
The stator S is provided with pole portions S1 and S2. The stators S are provided with pole portions S1 and S2.
A pole and an S pole are generated respectively. This allows the rotor R to rotate in both forward and reverse directions. A sector A driven by the rotation of the motor M to open and close the shutter opening A1.
Reference numerals 2, A3 are arranged symmetrically with respect to the shutter opening A1, and the sector A3 is rotatably supported around an axis A4 protruding from a main plate (not shown). Sector A2
Is rotatably supported around an axis A5 which is press-fitted and fixed to the rotor R. A sector opening / closing lever A6 is supported on the upper surface of the sector A2 so as to be rotatable about the axis A5. The arm portion A7 of the sector opening / closing lever A6 is engaged with an engaging pin A8 provided on the main plate, the sector opening / closing lever pin A9 of the sector opening / closing lever A6 is axially attached to the sector A2, and is engaged with the groove A3a of the sector A3. Combined sector A
2. A3 is driven. The sector opening / closing lever A6 is normally urged clockwise by a spring A10. In this example, when the motor coil L11 is energized, the aperture / shutter A opens to open the shutter opening A1, the imaging light reaches the CCD in the CCD 4, and when the motor coil L12 is energized, the aperture / shutter A closes. The shutter opening A1 is set to close. Next, the operation will be described with reference to FIG. 3, FIG. 4, and FIG. First,
The operation when the strobe non-use mode is designated by a mode switch (not shown) or the like will be described with reference to FIG. It should be noted that in FIG.
Indicates output states of the charging start signal STc, the charging signal SMt, and the charging signal SSt, respectively, Mo and Ms indicate voltage waveforms of the terminals Mo and Ms in FIG. 1, and the opening is the opening state of the shutter opening A1 in FIG. , CCD indicates the operation state of the CCD 4, STt indicates the output state of the strobe trigger signal STt, VCMT and VCST indicate the charging voltage waveforms of the shutter capacitor CMT and the strobe capacitor CST, respectively, and LCD indicates the operation state of the LCD 5. Is shown. It is assumed that the parallel connection signal PAL is not output in the initial state. When the power is turned on by operating a power switch (not shown) (see t1), the CPU 1 starts the operation, and after the operation such as the initial reset is completed, outputs the charge start signal STc to the CG 6. The CG 6 starts operating in response to the input of the charge start signal STc. At this time, since the transistor TR4 connected to the shutter capacitor CMT and the transistor TR3 connected to the strobe capacitor CST are off, the respective capacitors CMT and CST are not charged (see t1 to t2). Subsequently, since the strobe non-use mode is designated, the CPU 1 outputs only the charging signal SMt among the charging signals SMt and SSt (see t2). The transistor TR4 is turned on by the charging signal SMt, and the shutter capacitor CMT is charged by the output of CG6 input via the diode D3 (see t2 to t3).
At this time, the CPU 1 operates the AE2 and the AF3,
Obtain subject brightness and subject distance. This AE2 and AF
Operation 3 is repeated. Shutter capacitor C
When the charging of the MT proceeds and the charging voltage reaches the charging completion level voltage Vmax, the voltage detection circuit VDT2 outputs a charging completion signal SHfc to the CPU 1. When receiving the charging completion signal SHfc, the CPU 1 outputs a pulse P1 to the terminal Mo to drive the motor coil L11, opens the aperture / shutter A (see t3 to t4), and supplies the imaging light to the CCD in the CCD4. . At this time, the motor coil L11
Is supplied with the charging voltage of the shutter capacitor CMT via the regulator REG2. This motor coil L
The operation 11 causes the charging voltage of the shutter capacitor CMT to decrease, but the charging by the CG 6 increases the voltage again. When the charging voltage of the shutter capacitor CMT reaches the charging completion level voltage Vmax again, the charging completion signal S
Tfc is output again from the voltage detection circuit VDT2, and CP
U1 stops the output of the charge signal SMt by this output to open one end of the shutter capacitor CMT, and stops the output of the charge start signal STc, and CG6
Is stopped (see t5). When the operation of the CG 6 is stopped, the CPU 1 determines whether the charging completion signal STfc or the motor operable signal SHfb is output from the voltage detection circuit VDT2, and if any one of them is output, a predetermined display (release OK, etc.) Is displayed on the display means DSP, and a so-called release operation accompanying an ON operation of a release switch (not shown) is enabled. That is, after the charging of the shutter capacitor CMT is completed, the charging voltage becomes the minimum driving voltage Vth of the motor M.
If it exceeds 1, the operation of the release switch is accepted. Subsequently, the CPU 1 operates the CCD 4 and the LCD 5. Specifically, power supply to the CCD 4 is started, and
The CCD in the CCD 4 is driven by the CCD driving circuit in the D 4 to output a captured image, and the LCD 5 displays the captured image. The operation of the CCD driving circuit in the CCD 4 is as follows. First, the CCD in the CCD 4 is initialized (unnecessary charge is discharged), and the CCD in the CCD 4 is shuttered for a charge accumulation time set based on the subject brightness detected by the AE 2. The imaging light passing through the opening A1 is supplied to accumulate the electric charge, the accumulated electric charge is transferred to the video signal processing circuit in the CCD 4, and the operation returns to the initialization operation of the CCD and repeats the above operation. The video signal processing circuit in the CCD 4 outputs a video signal of a captured image to the CPU 1 based on the transferred charges. At this time, the CPU 1 drives a photographic lens (not shown) based on the subject distance detected by the AF 3,
A focusing operation is performed. In this state, the user is
In D5, the composition, that is, the captured image to be captured is determined while checking the captured image. When the composition is determined and the user operates the release switch (see t6), the CPU 1 sets the current C
After discharging the electric charge accumulated in the CCD in the CD4,
During the charge accumulation time set based on the subject brightness detected by the AE2, the imaging light is supplied to the CCD in the CCD 4 (see t7). When the set charge accumulation time elapses (see t8), the CPU 1 outputs the charge signal SMt to allow the charge to be extracted from the shutter capacitor CMT, and then outputs the pulse P2 to the terminal Ms to drive the motor coil L12. Then, the aperture / shutter A is closed (t
8-t9). At this time, the shutter capacitor CM is connected to the motor coil L12 via the regulator REG2.
A charging voltage of T is supplied. That is, no current flows from the battery E to the motor M when the motor for driving the aperture / shutter A is driven. As described above, since no current flows from the battery E to the motor M when the motor for driving the aperture / shutter (exposure control member) A is driven, it is possible to prevent the battery voltage from being temporarily lowered by driving the motor M. Therefore, for example, when the above-described configuration is used for a camera having a function of determining that the battery has run out when the battery voltage becomes lower than a predetermined value, the drive of the motor M that drives the aperture / shutter (exposure control member) A In some cases, it is possible to solve the problem that a battery that has been used for a short time after being used is determined as “battery exhausted”. This effect is particularly remarkable when used in a digital still camera in which a CCD, an electronic viewfinder, or the like is operating when a motor for driving an exposure control member is driven. In other words, in such a digital still camera,
The drive of the motor that drives the exposure control member and the operation of the CCD and the electronic viewfinder overlapped, and the battery voltage temporarily dropped when the motor was driven. Drop can be prevented. Therefore,
"Battery depleted" when the battery has been used for a while
Can be solved. Returning to FIG. 3, simultaneously with the closing operation of the aperture / shutter A, the C
The CD drive circuit transfers the charge stored in the CCD in the CCD 4 to a video signal processing circuit in the CCD 4, and the video signal processing circuit transfers a video signal based on the transferred charge to the CPU 1.
The CPU 1 stores the video signal in a storage medium (not shown) such as a flash memory or a magnetic memory and causes the LCD 5 to display the video signal. Thereafter, the CPU 1 outputs the pulse P3 to the terminal Mo, and opens the aperture / shutter (exposure control member) A. At this time, the voltage detection circuit VDT
If the motor operation enable signal SHfb is output from the control signal 2, it is determined that there is still enough charge in the shutter capacitor CMT to normally drive the motor, and the operation of the next release switch is awaited. When the detection signal SHfa is output from the VDT 2, it is determined that there is no remaining charge enough to normally drive the motor, a predetermined display (release NG, etc.) is displayed on the display means DSP, and the release operation is performed. After that, the shutter capacitor CMT is charged again as described above after turning off the LCD 5 which consumes a large amount of power. Thereafter, when the charge completion signal STfc is output from the voltage detection circuit VDT2, the state returns to the state at t5, and the above-described operation is repeated. As described above, when the strobe non-use mode is designated, only the shutter capacitor CMT is charged, so that unnecessary use of the battery for charging the strobe capacitor CST can be avoided, and the life of the battery can be extended. Next, an operation in a case where a strobe usable mode is designated by a mode switch or the like will be described with reference to FIG. The description of the same parts as the operations described with reference to FIG. 3 will be omitted, and the parts different from the operations shown in FIG. 3 will be described. After the pulse P1 is output to the terminal Mo and the aperture / shutter A is opened, the voltage detection circuit VDT2 outputs the charge completion signal SHfc,
When the output of the charging signal SMt is stopped, the CPU 1 outputs the charging signal SSt and turns on the transistor TR3 (t
50). By turning on the transistor TR3, the strobe capacitor CST is charged by the output of CG6 input via the diode D101 (see t50 to t60). When the charging of the strobe capacitor CST progresses and the charging voltage reaches the charging completion level voltage Vmax2, the voltage detection circuit VDT1 outputs the charging completion signal STfc to the CPU1.
Output to When the CPU 1 receives the charging completion signal STfc, the CPU 1 stops outputting the charging signal SSt to open one end of the strobe capacitor CST, stops outputting the charging start signal STc, and stops the operation of the CG 6 (see t60). ). When the operation of the CG 6 stops, the CPU
1 indicates that a charge completion signal SHfc or a motor operable signal SHfb is output from the voltage detection circuit VDT2 and a charge completion signal STfc or a strobe operable signal STfb is output from the voltage detection circuit VDT1.
A predetermined display (release OK or the like) is displayed on the display means DSP, and a so-called release operation accompanying an ON operation of a release switch (not shown) is enabled. That is, if the charging voltage of the shutter capacitor CMT exceeds the minimum driving voltage Vth1 of the motor M and the charging voltage of the strobe capacitor CST exceeds the minimum driving voltage Vth3 of strobe light, the operation of the release switch is accepted. Subsequently, the CPU 1 controls the CCD 4 and the LC
D5 is operated, and the operation of the release switch is awaited as in the case of FIG. When the composition is determined and the user operates the release switch (see t70), the CPU 1
After discharging the electric charge accumulated in the CCD in the AE 4, the AE
The imaging light is supplied to the CCD in the CCD 4 during the charge accumulation time set based on the subject brightness detected by the imaging device 2 (t8).
0 to t100). At this time, if the subject brightness is low, C
PU1 outputs a charge signal SSt so that charges can be taken out from the strobe capacitor CST, and outputs a strobe trigger signal STt during the charge accumulation time to perform strobe light emission. When the charge accumulation time ends, the aperture / shutter A is closed and the CCD 4 is operated as in the case described with reference to FIG. Subsequently, the CG 6 and the transistor TR3 are operated to recharge the strobe capacitor CST. At this time, in order to suppress the current value flowing out of the battery E, the LCD 5
Stop the operation of. Thus, the strobe capacitor CST and the shutter capacitor CMT are used by using the output of CG6.
, The configuration can be simplified as compared with the case where a charging circuit is provided for each capacitor. In other words, since the shutter capacitor is also charged using the conventional booster circuit for charging the strobe capacitor, there is no need to provide a dedicated booster circuit for the shutter capacitor. Also, each capacitor is charged at a timing at which the outflow current from the battery does not exceed a predetermined value even if the charging operation is performed after the power is turned on and other than during the shooting operation, and is not charged at the time of the shooting operation when the current is largest. That is, since charging is prohibited during the photographing operation, the charging operation and the photographing operation can be performed at different timings, and an increase in the peak current of the battery can be suppressed. Next, with reference to FIG. 5, the operation in the case where the continuous shooting mode without using the flash is designated by the mode switch or the like will be described. In the figure, Pal is a parallel connection signal PA.
The output state of L is shown. 3 and 4 in FIG.
The same reference numerals indicate the same components. In addition, the description of the same portions as the operations described with reference to FIGS. 3 and 4 will be omitted, and portions different from the operations illustrated in FIGS. 3 and 4 will be described. The outline of the operation in the continuous shooting mode is that if the charge and discharge of the shutter capacitor CMT are repeated during continuous shooting without using a flash, the photographing interval cannot be shortened. Therefore, the charge charged in the flash capacitor CST is used for driving the shutter. This shortens the charging / discharging time and shortens the photographing interval. When this mode is set, the CPU
1 is a strobe condenser CST and a shutter condenser C
And MT respectively. In this example, the periods T1, T2
To charge alternately. Of course, the charging may be performed on one side as shown in FIG. Period T1
If the width of T2 and T2 is proportional to the capacitance of the strobe capacitor CST and the shutter capacitor CMT, the charging time end timings of the respective capacitors become substantially equal.
When one of the capacitors has been charged first, the other capacitor is not charged alternately thereafter but only the other capacitor is charged. As described above, since the two capacitors are charged alternately, the peak current of the battery can be reduced as compared with the case where the two capacitors are charged simultaneously. When the charging voltage of the shutter capacitor CMT reaches the charging completion level voltage Vmax, a pulse is supplied to the terminal Mo to open the aperture / shutter A. When the charging of each capacitor is completed, the CPU 1 receives the operation of the release switch. When the release switch is operated here (see t300), the continuous shooting is started, and the CPU 1 sends the motor M to the shutter capacitor CMT.
Hold the charging signal SMt in the ON state so that the device can take charge. Pulse PM output to terminals Mo and Ms during continuous shooting
On, PMsn (both n = 1, 2, 3,...) causes the motor M to operate using the shutter capacitor CMT as a power supply. Voltage Vt
h1 and the voltage detection circuit VDT2 outputs the detection signal S
When Hfa is output, the CPU 1 outputs the charging voltage SSt and the parallel connection signal Pal, and outputs the shutter capacitor CMT
Are connected in parallel with a strobe capacitor CST. As a result, the strobe capacitor CST can be used as a power source for the motor M. This connection makes the charging voltages of the shutter capacitor CMT and the strobe capacitor CST equal. Note that the charging signal SSt and the parallel connection signal Pal may be output from the beginning according to the operation of the release switch. However, as described above, if the shutter capacitor CMT is used as a power supply first and the strobe capacitor CST is used as a power supply from the point in time when its charging voltage becomes low, the number of continuous shots is small (for example, two). Since the voltage capable of strobe light emission remains in the strobe condenser CST, there is an advantage that strobe shooting can be immediately performed for the third image. As described above, since the switch circuit for connecting the two capacitors in parallel is provided, the two capacitors can be integrated as one power supply. For example, when the charging voltage of one capacitor decreases, the charging voltage of the other capacitor can be supplied to one capacitor, and the charging voltage can be used effectively. Next, FIG. 6 shows a main part of another circuit configuration capable of performing the same operation as that of FIG. 1 by the same signal and output as that of FIG. 1, the same components and signals as those in FIG. 1 are denoted by the same reference numerals, and include a battery E, a voltage detection circuit VDT0, regulators REG1, AE2, AF3, CCD4, LCD5.
Although not shown, it is assumed that they are connected in the same manner as in FIG. In the figure, TR61 to TR64 are transistors, and R61 to R66 are resistors. In this case, the number of elements increases as compared with FIG. 1, but a large current for strobe light does not flow through the transistor TR61 connected to the strobe capacitor CST, so that it is not necessary to use an expensive IGBT as in FIG. Cost reduction can be achieved. Note that the actuator is not limited to a motor, and for example, a plunger or the like may be used. In the above description, the aperture / shutter having two open / close positions has been described. However, the present invention is not limited to this and can be applied to a multiple position aperture / shutter. Also, a two-coil type motor having an opposite phase (a type in which the magnetic force is reversed when a current flows) has been described as a motor, but a bridge type in which the direction of current is switched by one coil as in a conventional example may be used. A bridge type or four coil type stepping motor type may be used. Further, the exposure control member is not limited to the above. For example, a member that changes the aperture diameter or a member that switches between insertion and non-insertion of a member having a different transmitted light amount such as an ND filter may be used.

According to the present invention, in a digital camera or a so-called silver halide camera in which a large current needs to flow by using a battery as a power source, the shutter is charged in a capacitor previously charged by a flash booster circuit. , The motor drive current does not need to be taken from the battery during shooting with the largest current, so that the battery voltage does not drop much and the battery life can be extended. In addition, a dedicated capacitor for driving the motor is provided, so that the strobe can be used while the motor is operating, and when the strobe is not used, the motor can be driven by the electric charge stored in the strobe capacitor. The interval can be shortened. The present invention provides a booster circuit that boosts a battery voltage, a first capacitor that is charged via the booster circuit, a strobe light-emitting unit that operates using the first capacitor as a power supply, and a charger that is charged via the booster circuit. And the actuator that drives the exposure control member using the second capacitor as a power supply, so that the battery voltage does not drop due to the operation of the actuator that drives the exposure control member. Can be prevented. Also, since the first capacitor for strobe light emission and the second capacitor for driving the actuator are charged by one booster circuit,
The structure can be simplified. Further, since the first capacitor for strobe light emission and the second capacitor for driving the actuator are used, the power sources for strobe light emission and actuator drive are independent, and their operations do not affect each other's power supply voltage fluctuation. , Each operation can be stabilized. If a charging / discharging circuit is provided for each of the first capacitor and the second capacitor, and these charging / discharging circuits are operated independently, the degree of freedom in the timing of charging / discharging each is improved. If the first capacitor and the second capacitor are charged alternately, the peak current of the battery can be reduced as compared with the case of charging at the same time. If a switch circuit for connecting the first capacitor and the second capacitor in parallel is further provided, the two capacitors can be integrated as one power supply. For example, when the charging voltage of one capacitor decreases, the charging voltage of the other capacitor can be supplied to one capacitor. When the strobe non-use mode is designated, if only the second capacitor for the actuator is charged out of the first capacitor and the second capacitor, the unnecessary first capacitor is charged by the battery. Can be avoided, and the battery life can be extended. If charging of the first capacitor and the second capacitor is prohibited during the photographing operation, the charging operation and the photographing operation can be performed at different timings, and an increase in the peak current of the battery can be suppressed. A booster circuit for boosting the battery voltage, a capacitor charged through the booster circuit, and an actuator for driving the exposure control member using the capacitor as a power source, so that the actuator for driving the exposure control member It is possible to prevent the battery voltage from dropping during operation.
Preferably, the exposure control member is a camera shutter member or a camera aperture member. A voltage detection circuit that detects a state where the voltage of the battery is equal to or lower than a predetermined value, a control circuit that operates using the battery as a power source, controls the operation of the actuator, and has a minimum operation guarantee voltage smaller than the predetermined value; When the voltage detection circuit detects a voltage equal to or less than the predetermined value, a determination unit that determines that the battery is dead can be further provided, so that the battery voltage can be prevented from dropping due to the operation of the actuator that drives the exposure control member. In addition, it is possible to reduce the problem that even a battery that has been used for a short time has been determined to be "battery exhausted".

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention.

FIG. 2 is a detailed view of a main part of FIG. 1;

FIG. 3 is a timing chart for explaining the operation of FIG. 1;

FIG. 4 is a timing chart for explaining the operation of FIG. 1;

FIG. 5 is a timing chart for explaining the operation of FIG. 1;

FIG. 6 is a circuit diagram showing another embodiment of the present invention.

FIG. 7 is a circuit diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control circuit, judgment means 6 Booster circuit A Exposure control member E Battery M Actuator Xe Strobe light emitting part CST First capacitor CMT Second capacitor SC1 Switch circuit TR3 Charge / discharge circuit TR4 Charge / discharge circuit TR61 Charge / discharge circuit TR63 Charge / discharge Circuit MDR1 Drive circuit VDT0 Voltage detection circuit

Continued on the front page F term (reference) 2H002 AB04 BC01 BC03 BC11 2H053 AB03 AC21 BA04 BA06 BA08 CA21 2H081 AA51 BB12 BB34 CC66 5C022 AA13 AB15 AB22 AB40 AC03 AC42 AC52 AC56 AC69 AC74

Claims (9)

[Claims] 1. A booster circuit for boosting a battery voltage, a first capacitor charged via the booster circuit, a strobe light emitting unit which operates using the first capacitor as a power supply, and An exposure control drive device comprising: a second capacitor to be charged; and an actuator that drives an exposure control member using the second capacitor as a power supply. 2. The method according to claim 1, wherein each of the first capacitor and the second capacitor is provided with a charge / discharge circuit, and these charge / discharge circuits operate independently. Exposure control drive. 3. The exposure control driving device according to claim 1, wherein the first capacitor and the second capacitor are charged alternately. 4. The exposure control driving device according to claim 1, further comprising a switch circuit for connecting the first capacitor and the second capacitor in parallel. 5. The method according to claim 1, wherein when the strobe non-use mode is designated, only the second capacitor of the first capacitor and the second capacitor is charged. Exposure control drive. 6. The method according to claim 1, wherein the first capacitor and the second capacitor are:
An exposure control driving device wherein charging is prohibited during a shooting operation. 7. A booster circuit for boosting a battery voltage, a capacitor charged by an output via the booster circuit, and an actuator for driving an exposure control member using the capacitor as a power supply. Exposure control drive. 8. The method of claim 1, 2, 3, 4, 5, 6, or 7.
, Wherein the exposure control member is a camera shutter member or a camera aperture member. 9. The voltage detection circuit according to claim 1, 2, 3, 4, 5, 6, 7, or 8, wherein the voltage detection circuit detects a state in which the voltage of the battery is equal to or lower than a predetermined value; A control circuit that controls the operation of the actuator and has a minimum operation guarantee voltage smaller than the predetermined value; and a determination unit that determines that the battery is dead when the voltage detection circuit detects a voltage equal to or less than the predetermined value. An exposure control driving device, characterized in that: