JP2003060977A - Electronic camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic camera that discharges unwanted electric charges separately for a plurality of number of times from a release operation, until starting exposure for photographing. SOLUTION: When an operation signal is inputted from a release switch, a signal PWON is set to an H level and a signal EJECT is set to H level with a timing t1. Thus, an imaging element starts discharging unwanted electric charges. The signal EJECT is set once to an L level in a timing t3. Thus, the imaging element stops discharging unwanted electric charges and is deactivated with a timing t3. The signal EJECT is reset to an H level in a timing t4. Thus, the imaging element restarts discharging unwanted electric charges. The signal EJECT is set to an L level and a signal CLOSE is set to an H level in a timing t5. A shutter starts its releasing, the imaging element stops discharging the unwanted electric charges and stores the electric charges. The shutter completes releasing with a timing t6 and a stored electric charge signal is read from the imaging element. The signal PWON is set to an L level with a timing t7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic camera that captures an image of a subject using a charge storage type light receiving element.

[0002]

2. Description of the Related Art An electronic camera for picking up an image of a subject using a charge storage type light receiving element such as a CCD is known. In this electronic camera, when the camera is released, the gate of the CCD is once opened to discharge the charge before the exposure is started, and the charge generated in the photoelectric conversion element and the charge accumulated in the charge accumulating portion are removed. It is discharged as unnecessary charges. After discharging unnecessary charges, the gate is closed and exposure for photographing is started.

[0003]

In order to sufficiently discharge unnecessary charges, it is necessary to discharge unnecessary charges for a predetermined time depending on the light receiving element. Generally, a large amount of electric power is required for the unnecessary charge discharging operation of the charge storage type light receiving element. Therefore, if the unnecessary charge discharging operation is performed with the battery capacity of the camera reduced, the unnecessary charge discharging operation may not be sufficiently performed due to the decrease in the battery voltage, or the photographing operation performed after the unnecessary charge discharging operation cannot be performed. . In particular, when the number of pixels of the light receiving element is large, power consumption is large, which is likely to cause a problem.

An object of the present invention is to provide an electronic camera in which unnecessary charge discharging operation is separately performed.

[0005]

An electronic camera according to the present invention includes a charge storage type light receiving element, an image pickup device for picking up a subject image and outputting an image pickup signal, a drive circuit for driving the image pickup device, and at least an image pickup device. The power supply circuit that supplies power to the device and the drive circuit, and the unnecessary charge discharging operation is performed a plurality of times between the release operation and the start of the exposure of the imaging device, including the time when the unnecessary charge discharging operation is not operated. Thus, the above-mentioned object is achieved by providing the control circuit which causes the drive circuit to perform the operation at a certain interval. The power circuit is DC /
It may be configured to include a DC converter. The electronic camera further includes a voltage detection circuit that detects the voltage of a battery that supplies power to the power supply circuit, and the control circuit includes the voltage detection circuit before and after the unnecessary charge discharging operation by the drive circuit is started. When the difference between the voltages detected by the above exceeds a predetermined value, the driving circuit can be made to perform the unnecessary charge discharging operation a plurality of times. The electronic camera further includes a temperature detection circuit that detects the ambient temperature of the battery, and the control circuit, when the temperature detected by the temperature detection circuit is below a predetermined value,
It is also possible to cause the drive circuit to perform the unnecessary charge discharging operation a plurality of times. The electronic camera further includes a voltage detection circuit that detects the voltage of a battery that supplies power to the power supply circuit, and the control circuit controls the drive circuit when the voltage detected by the voltage detection circuit when the camera is powered on is below a predetermined value. It is also possible to cause the unnecessary charge discharging operation to be performed a plurality of times. The electronic camera further includes a light emission instruction detection circuit that detects that the flash device is instructed to emit light, and reflected light from the preliminary light emitted from the flash device between the release operation and the start of exposure of the imaging device. And a dimming circuit that calculates the amount of light emission of the flash device required after the start of exposure according to the amount of reflected light, and the control circuit, when the light emission instruction is detected by the light emission instruction detection circuit, the drive circuit. It is also possible to control the dimmer circuit so that the unnecessary charge discharging operation is performed a plurality of times and the light emission amount is calculated while the unnecessary voltage discharging operation is inactive.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. First Embodiment FIG. 1 is a block diagram showing the outline of the electronic still camera according to the first embodiment of the present invention. In FIG. 1, the electronic still camera includes an image sensor 1, a drive circuit 2, and a DC.
A / DC converter 3, a battery 4, an arithmetic circuit 5, a temperature sensor 6, a flash device 7, a signal processing circuit 8 and a shutter device 9.

The battery 4 supplies electric power consumed by the camera. The DC / DC converter 3 converts the voltage input from the battery 4 into a voltage required by each circuit in the camera, and supplies the converted voltage to each circuit. DC / DC converter 3
When the voltage input from the battery 4 falls below a predetermined input threshold voltage, at least the drive circuit 2 and the image sensor 1
It has a shutdown function to shut off the voltage output to.
The temperature sensor 6 is arranged near the battery 4, detects the temperature of the battery 4, and outputs a detection signal to the arithmetic circuit 5. The flash device 7 emits illumination light for illuminating a subject at the time of shooting according to a light emission instruction sent from the arithmetic circuit 5.

The arithmetic circuit 5 controls the entire camera. The subject brightness detected by a brightness detection circuit (not shown) is input to the arithmetic circuit 5. Further, the arithmetic circuit 5 is also inputted with respective setting values by an aperture value setting member, a shutter time setting member and an exposure sensitivity setting member (not shown). When the camera is released, the arithmetic circuit 5 performs a predetermined exposure calculation based on the set value input from each of the setting members and the detected subject brightness, and outputs an operation instruction signal to the drive circuit 2. In addition to the output, a curtain opening instruction signal is output to the shutter device 9. The drive circuit 2 generates a timing control signal necessary for the image sensor 1 to discharge unnecessary charges, accumulate charges, and sweep out accumulated charges, and outputs the timing control signal to the image sensor 1. The shutter device 9 controls opening / closing of a shutter curtain (not shown) according to the curtain opening instruction signal.

The image pickup device 1 constituting the image pickup device accumulates signal charges according to the brightness of the subject image formed on the image pickup surface. The signal charge accumulated in the image pickup device 1 is swept out by a timing signal sent from the drive circuit 2 and input to the signal processing circuit 8 as an image pickup signal. The signal processing circuit 8 includes a CDS circuit and removes noise included in the image pickup signal output from the image pickup device 1. The noise-removed image pickup signal is amplified by a predetermined gain and then converted from an analog signal to a digital signal. The converted image data is subjected to image processing such as gamma correction and color temperature adjustment.

The image data after the image processing is processed into a predetermined recording format and then recorded on a recording medium such as a memory card (not shown) or processed into image data for display on a display monitor (not shown). Is output.

The arithmetic circuit 5 described above has an internal A (not shown).
It has a / D converter and is configured to detect the voltage of the battery 4. The arithmetic circuit 5 determines whether or not the remaining capacity of the battery 4 has a margin depending on the detected voltage of the battery 4.
The state of the battery 4 is determined whether or not is deteriorated.

FIG. 2 is a time chart for explaining the control timing of the image pickup device 1 in the photographing sequence performed by the arithmetic circuit 5 after the above-mentioned camera release. In FIG. 2, the signal PWON is a signal for the arithmetic circuit 5 to instruct the drive circuit 2 to generate a timing control signal. When the signal PWON is at the H level, the drive circuit 2 performs the timing control signal generating operation, and when the signal PWON is at the L level, the drive circuit 2 stops the timing control signal generating operation. DC / DC while the drive circuit 2 generates the timing control signal
Electric power is supplied from the converter 3 to the drive circuit 2 and the image pickup device 1.

The signal EJECT is a signal for the arithmetic circuit 5 to instruct the drive circuit 2 to generate a timing control signal necessary for the unnecessary charge discharging operation. When the signal EJECT is at H level, the drive circuit 2 performs the control signal generation operation required for discharging unnecessary charges, and when the signal EJECT is at L level, the drive circuit 2 stops the control signal generation operation required for discharging unnecessary charges. . Signal CLOS
E is a signal for the arithmetic circuit 5 to instruct the shutter device 9 to perform a curtain opening operation. When the signal CLOSE is at the H level, the shutter device 9 performs the curtain opening operation, and when the signal CLOSE is at the L level, the shutter device 9 stops the curtain opening operation.

When an operation signal is input from a release switch (not shown), the arithmetic circuit 5 sets the signal PWON to H level at the timing t1 in FIG. The arithmetic circuit 5 sets the signal EJECT to the H level at the timing t2. As a result, the image sensor 1 starts the unnecessary charge discharging operation. In the unnecessary charge discharging operation, the charge discharging gate, the storage shift gate, and the reading gate (not shown) in the image pickup device 1 are opened, and the charges generated by the photoelectric conversion photodiode and the charges accumulated in the charge storage unit are discharged. , The operation of discarding via the charge discharging drain and the charge transfer CCD register. Since this charge discharging operation is performed at high speed, the image pickup device 1 and the drive circuit 2 consume a lot of power.

At timing t3, the arithmetic circuit 5 temporarily sets the signal EJECT to L level. Since the drive circuit 2 stops the control signal generating operation necessary for discharging the unnecessary charges, the image pickup device 1 stops the unnecessary charge discharging operation and becomes inoperative. As a result, the current consumed by the camera decreases and the voltage of the battery 4 increases. For example, 1 msec from timing t3
At timing t4 after the elapse, the arithmetic circuit 5 sets the signal EJECT to the H level again. Thereby, the image sensor 1
Restarts the unnecessary charge discharging operation. At timing t5, the arithmetic circuit 5 sets the signal EJECT to L level and the signal CLOSE to H level. When the signal EJECT is set to the L level, the drive circuit 2 stops the control signal generating operation required for discharging unnecessary charges, and the image sensor 1 stops the unnecessary charge discharging operation.

On the other hand, when the signal CLOSE is set to H level,
The shutter device 9 starts the curtain opening operation. The arithmetic circuit 5 is
The drive circuit 2 is instructed to perform a control signal generation operation required for charge storage. As a result, the image pickup device 1 starts exposure for photographing to accumulate charges. At timing t6, the shutter device 9 ends the curtain opening operation. Here, the actual exposure time is the time during which the so-called electronic shutter control is performed and controlled in the time period from the timing t5 to the timing t6. The arithmetic circuit 5 is configured to drive the drive circuit 2 after the charge is accumulated.
Is instructed to generate a control signal necessary for sweeping out accumulated charge. As a result, the accumulated charge signal is read from the image sensor 1 to the signal processing circuit 8. At timing t7, when the arithmetic circuit 5 sets the signal PWON to the L level, the drive circuit 2 stops generating the timing control signal and
The power supply from the DC / DC converter 3 to the drive circuit 2 and the image sensor 1 is stopped.

As described above, according to the first embodiment, the unnecessary charge discharging operation performed from the release operation (timing t1) to the start of exposure for photographing (timing t5) is performed at a timing. After the time from t2 to t3, the operation is stopped and the operation is stopped. Since the unnecessary electric charge discharging operation consumes a large amount of electric power, when the discharging capacity of the battery 4 is advanced and the remaining capacity is small, the voltage of the battery 4 is quickly reduced with the unnecessary electric charge discharging operation. When the lowered voltage becomes lower than the input threshold voltage of the DC / DC converter 3 described above, the shutdown function of the DC / DC converter 3 stops the power supply to the drive circuit 2 and the image pickup device 1, and the unnecessary charges are sufficiently discharged. I don't know. However, the voltage of the battery 4 is restored by stopping the unnecessary charge discharging operation from timing t3 to t4, and the unnecessary charge discharging operation can be performed again from timing t4 to t5. As a result, unnecessary charges can be sufficiently discharged, and
Since the influence of noise due to the dark current in the image sensor 1 can be eliminated, the quality of the captured image can be improved.

If the voltage of the battery 4 is recovered and the DC / DC converter 3 can be prevented from shutting down by temporarily stopping the unnecessary electric charge discharging operation and performing the intermittent operation, the camera performs timing t5 and thereafter after the unnecessary electric charge discharging operation. A shooting sequence can be performed. That is, when the discharge of the battery 4 progresses and the remaining capacity is reduced, the number of captured images can be increased as compared with the case where the unnecessary charge discharging operation is not divided into a plurality of operations.

It should be noted that the total time of the unnecessary charge discharging operation divided into a plurality of times by being once stopped is, for example, 20 msec or more. The unnecessary charge discharging operation may be divided into equal time periods or non-uniform time periods.

In the above description, the unnecessary charge discharging operation is performed twice, but it may be performed three times or more.

Second Embodiment In the second embodiment, when the difference A between the voltages of the battery 4 before and after starting the unnecessary charge discharging operation is larger than a predetermined value, the unnecessary charge discharging is performed. Stop the operation once and divide it into multiple times. FIG. 3 is a time chart explaining the control timing of the image sensor 1 according to the second embodiment. The voltage waveform VB is the terminal voltage (battery voltage) of the battery 4 detected by the arithmetic circuit 5.

When an operation signal is input from a release switch (not shown), the arithmetic circuit 5 causes the timing t11 shown in FIG.
The signal PWON is set to H level. The arithmetic circuit 5 sets the signal EJECT to the H level at the timing t12.
As a result, the image sensor 1 starts the unnecessary charge discharging operation. The arithmetic circuit 5 starts monitoring the voltage of the battery 4. The voltage monitoring sequentially calculates the difference A between the battery voltage detected before the signal EJECT is set to the H level and the battery voltage detected after the signal EJECT is set to the H level, and whether the difference A exceeds a predetermined value. This is done by determining whether or not.

If the difference A does not exceed a predetermined value, the battery 4
It is considered that there is little voltage drop due to the unnecessary charge discharging operation and there is a margin in the remaining capacity of the battery 4. In this case, the unnecessary charge discharging operation is continuously performed without being temporarily stopped. When the arithmetic circuit 5 determines that the difference A does not exceed the predetermined value,
At timing t15, the signal EJECT is set to L level and the signal CLOSE is set to H level. Timing t
15 sets the signal EJECT to H level, and then, for example,
It is the time when 20 msec has elapsed. When the signal EJECT is set to the L level, the drive circuit 2 stops the control signal generating operation required for discharging unnecessary charges, and the image sensor 1 stops the unnecessary charge discharging operation. On the other hand, when the signal CLOSE is set to the H level, the shutter device 9 starts the curtain opening operation. Arithmetic circuit 5
Instruct the drive circuit 2 to perform a control signal generation operation required for charge storage. As a result, the image sensor 1 starts exposure for photographing and accumulates charges. At timing t16, the shutter device 9 ends the curtain opening operation. Arithmetic circuit 5
Instructs the drive circuit 2 to perform the control signal generation operation necessary for sweeping out the accumulated charges after the charges are accumulated. Timing t1
In FIG. 7, when the arithmetic circuit 5 sets the signal PWON to the L level, the drive circuit 2 stops the generation of the timing control signal and the power supply from the DC / DC converter 3 to the drive circuit 2 and the image sensor 1 is stopped. .

When the difference A exceeds the predetermined value, it is considered that the voltage drop due to the unnecessary charge discharging operation of the battery 4 is large and the remaining capacity of the battery 4 has no margin. In this case, the unnecessary charge discharging operation is temporarily stopped and divided into a plurality of times. Arithmetic circuit 5
Determines that the difference A exceeds the predetermined value at the timing t13, the signal EJECT at the timing t13 ′.
To L level once. Since the drive circuit 2 stops the control signal generating operation necessary for discharging the unnecessary charges, the image pickup device 1 stops the unnecessary charge discharging operation and becomes inoperative. This allows
The current consumed by the camera decreases and the voltage of the battery 4 increases. For example, at timing t14, which is 1 msec after the timing t13 ′, the arithmetic circuit 5 again outputs the signal.
Set EJECT to H level. As a result, the image sensor 1 restarts the unnecessary charge discharging operation. At timing t15, the arithmetic circuit 5 sets the signal EJECT to L level and the signal CLOSE to H level. When the signal EJECT is set to the L level, the drive circuit 2 stops the control signal generating operation required for discharging unnecessary charges, and the image sensor 1 stops the unnecessary charge discharging operation. In this case, the timing t
It is assumed that the total time from 12 to t13 ′ and from timing t14 to t15 is at least 20 msec, for example.

When the signal CLOSE is set to the H level, the shutter device 9 starts the curtain opening operation. The subsequent operation is the same as when it is determined that the above-mentioned difference A does not exceed the predetermined value, and thus the description thereof is omitted.

As described above, according to the second embodiment, the difference A of the battery voltage detected before the signal EJECT is set to the H level and after the signal EJECT is set to the H level is sequentially calculated, It is determined whether the difference A exceeds a predetermined value. When the difference A exceeds a predetermined value (when the voltage drop of the battery 4 is large), exposure for photographing is started (timing t15).
The unnecessary charge discharging operation performed up to is from timing t12
When it is performed up to t13 ', it is temporarily stopped, and timings t14 to t
It was restarted up to 15, and it tried to do more. As a result, the timings t13 ′ to t14 are the same as in the first embodiment.
Since the voltage of the battery 4 is restored by suspending the unnecessary charge discharging operation up to, the camera can perform the shooting sequence after the timing t15.

In the above description, the difference A of the battery voltage detected before the signal EJECT is set to the H level and after the signal EJECT is set to the H level is sequentially calculated. If the difference A exceeds a predetermined value, it is unnecessary. The charge discharging operation is divided into multiple times. Alternatively, the voltage of the battery 4 detected when the power of the camera is turned on may be detected, and the unnecessary charge discharging operation may be divided into a plurality of times when the detected value is lower than the initial voltage threshold. Generally, as the battery 4 deteriorates, the internal resistance increases and the terminal voltage decreases. Therefore, the arithmetic circuit 5 is the battery 4
By controlling the drive circuit 2 so that the unnecessary charge discharging operation is divided into a plurality of times by determining the deterioration of the battery 4, the battery 4 is deteriorated in a deteriorated state as compared with the case where the unnecessary charge discharging operation is continuously performed without dividing. You can increase the number of shots.

The temperature of the battery 4 may be detected, and the unnecessary charge discharging operation may be divided into a plurality of times when the detected temperature is, for example, 10 ° C. or lower. Generally, in the battery 4, the internal resistance increases as the ambient temperature decreases, the terminal voltage decreases, and the discharge capacity also decreases. Therefore, the arithmetic circuit 5 controls the drive circuit 2 to divide the unnecessary charge discharging operation into a plurality of times according to the temperature around the battery 4 detected by the temperature sensor 6, so that the camera is placed in a low temperature environment. It is possible to increase the number of shots in the exposed state as compared with the case where the unnecessary charge discharging operation is not divided.

-Third Embodiment- In the third embodiment, the unnecessary charge discharging operation is divided into a plurality of times when the flash device 7 is instructed to emit light. Figure 4
[FIG. 8] is a time chart illustrating control timing of the image sensor 1 according to the third embodiment. The signal P is a dimming pulse waveform indicating the start timing of the dimming calculation performed by the arithmetic circuit 5.

The dimming calculation will be described below. The arithmetic circuit 5 causes the flash device 7 to perform preliminary light emission in order to determine the light emission amount of the flash device 7 at the time of shooting. The arithmetic circuit 5 measures the light from the subject illuminated by the preliminary light emission with a light metering circuit (not shown), and calculates the light emission amount of the flash device 7 during the main light emission based on the result of the light measurement. When an instruction to cause the flash device 7 to emit light is input by an operation member (not shown), the arithmetic circuit 5 causes the flash device 7 to perform preliminary light emission at the timing of setting the signal P in FIG. 4 to the H level. The arithmetic circuit 5 calculates, based on the photometric value at the time of preliminary light emission, the light emission time of the flash device 7, the light emission intensity, and the respective set values by the above-mentioned aperture value setting member and exposure sensitivity setting member (not shown).
The light emission amount (light emission time) of the flash device 7 during the main light emission is determined.

If the power supply voltage supplied to the photometry circuit fluctuates when performing photometry during the above-described preliminary flash, it becomes difficult to accurately calculate the amount of light emitted during main flash. In the third embodiment, when the flash device 7 is instructed to emit light, the unnecessary charge discharging operation is temporarily stopped and divided into a plurality of times, and the dimming calculation is performed while the unnecessary charge discharging operation is deactivated. I do.

When an operation signal is input from a release switch (not shown), the arithmetic circuit 5 causes the timing t21 in FIG.
The signal PWON is set to H level. The arithmetic circuit 5 sets the signal EJECT to the H level at the timing t22.
As a result, the image sensor 1 starts the unnecessary charge discharging operation. The arithmetic circuit 5 receives the signal EJ at the timing t12.
Set ECT to L level once. Since the drive circuit 2 stops the control signal generating operation necessary for discharging unnecessary charges, the image sensor 1
Stops the unnecessary charge discharging operation and becomes inactive. As a result, the current consumed by the camera decreases and the voltage of the battery 4 increases. At a timing t24 after the lapse of Δt from the timing t23, the arithmetic circuit 5 sets the signal P indicating the start timing of the dimming calculation to the H level. As a result, the flash device 7 is instructed to perform preliminary light emission, and the arithmetic circuit 5 starts the dimming calculation. Δt is, for example, 1 msec or more.

At timing t25 after completion of the light control calculation, the calculation circuit 5 sets the signal EJECT to the H level again.
As a result, the image sensor 1 restarts the unnecessary charge discharging operation. At timing t26, the arithmetic circuit 5 outputs the signal EJEC.
T is set to L level and signal CLOSE is set to H level. When the signal EJECT is set to the L level, the drive circuit 2 stops the control signal generating operation necessary for discharging the unnecessary charges, so that the image sensor 1 stops the unnecessary charge discharging operation. In this case, it is assumed that the total time from the timing t22 to t23 and the timing t25 to t26 is at least 20 msec, for example.

When the signal CLOSE is set to the H level, the shutter device 9 starts the curtain opening operation. Arithmetic circuit 5
Directs the drive circuit 2 to perform a control signal generating operation required for charge storage. As a result, the image sensor 1 starts exposure for photographing and accumulates charges. The arithmetic circuit 5 sends to the flash device 7 a signal instructing the main light emission together with the information indicating the light emission amount obtained by the light adjustment calculation. At timing t27, the shutter device 9 ends the curtain opening operation. The arithmetic circuit 5 instructs the drive circuit 2 to perform a control signal generating operation required for sweeping out accumulated charges. As a result, the accumulated charge signal is read from the image sensor 1 to the signal processing circuit 8. At timing t28, when the arithmetic circuit 5 sets the signal PWON to the L level, the drive circuit 2 stops generating the timing control signal, and the power supply from the DC / DC converter 3 to the drive circuit 2 and the image sensor 1 is stopped. It

As described above, according to the third embodiment, when the flash device 7 is instructed to emit light, the release operation is performed (timing t21) and the exposure for photographing is started (timing t26). When the unnecessary charge discharging operation performed up to ()) is performed from timing t22 to t23, the operation is temporarily stopped, and restarted from timing t25 to t26, and further performed. When the discharge of the battery 4 progresses and the remaining capacity is reduced, the voltage of the battery 4 which has dropped due to the unnecessary charge discharging operation is recovered between timings t23 and t24.
At timing t24, the arithmetic circuit 5 sets the signal P indicating the start of the dimming calculation to the H level, and the dimming calculation is performed with the voltage of the battery 4 recovered. As a result, since the power supply voltage supplied to the photometric circuit does not change when performing the photometry during the preliminary light emission, it is possible to accurately calculate the light emission amount during the main light emission.

The electronic still camera described above has been described by exemplifying a camera capable of changing the settings of the lens aperture value and the shutter speed. However, the lens aperture value is fixed or the shutter speed is fixed. The present invention can also be applied to a camera.

The present invention can be applied to the electronic still camera described above regardless of whether it is a single lens reflex type camera or a non-single lens reflex type camera.

The flash device 7 may be of a type built in the camera or of a type externally attached to the camera.

Correspondence between each component in the claims and each component in the embodiment of the invention will be described. The charge storage type image sensor is, for example, the image sensor 1
Composed by. The power supply circuit is, for example, DC / D
It is configured by the C converter 3. The control circuit is composed of, for example, the arithmetic circuit 5. The voltage detection circuit is composed of, for example, the arithmetic circuit 5. The temperature detection circuit is composed of, for example, the temperature sensor 6. The light emission instruction detection circuit is composed of, for example, the arithmetic circuit 5. The dimming circuit is composed of, for example, the arithmetic circuit 5.

[0040]

As described above in detail, in the electronic camera according to the present invention, even if the battery capacity of the camera is reduced, the unnecessary charge discharging operation of the image pickup device can be sufficiently performed, and the unnecessary charge discharging operation after the unnecessary charge discharging operation can be performed. The exposure operation can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of an electronic still camera according to a first embodiment.

FIG. 2 is a diagram illustrating a time chart illustrating control timing of an image sensor.

FIG. 3 is a diagram showing a time chart for explaining control timing of the image sensor according to the second embodiment.

FIG. 4 is a diagram showing a time chart for explaining control timing of an image sensor according to a third embodiment.

[Explanation of symbols]

1 ... Image sensor, 2 ... Drive circuit, 3
... DC / DC converter, 4 ... Battery, 5 ... Arithmetic circuit, 6 ... Temperature sensor, 7 ... Flash device, 8 ... Signal processing circuit, 9 ... Shutter device,

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // H04N 101: 00 H01L 27/14 BF term (reference) 2H002 CD13 JA07 2H053 AD08 AD23 4M118 AA10 AB01 BA10 CA02 FA06 5C022 AA13 AB03 AB12 AB17 AB40 AC42 AC52 AC69 AC73 5C024 AX01 BX01 CX53 DX04 GY01 GZ22 HX47 JX21

Claims (6)

[Claims] 1. An image pickup apparatus comprising a charge storage type light receiving element, which picks up a subject image and outputs an image pickup signal, a drive circuit which drives the image pickup apparatus, and supplies power to at least the image pickup apparatus and the drive circuit. Between the release operation and the start of the exposure of the imaging device after the release operation, and the unnecessary charge discharging operation is performed a plurality of times at intervals such that the unnecessary charge discharging operation includes a non-operation time. An electronic camera comprising: a control circuit that causes a drive circuit to perform. 2. The electronic camera according to claim 1, wherein the power supply circuit includes a DC / DC converter. 3. The electronic camera according to claim 1, further comprising a voltage detection circuit that detects a voltage of a battery that supplies power to the power supply circuit, wherein the control circuit discharges unnecessary charges by the drive circuit. When the difference between the voltages detected by the voltage detection circuit before and after the operation is started exceeds a predetermined value, the drive circuit is caused to perform the unnecessary charge discharging operation a plurality of times. Electronic camera to do. 4. The electronic camera according to claim 1, further comprising a temperature detection circuit that detects an ambient temperature of the battery, wherein the control circuit is configured to detect a temperature detected by the temperature detection circuit. An electronic camera, wherein the driving circuit is caused to perform the unnecessary charge discharging operation a plurality of times when the driving voltage is a predetermined value or less. 5. The electronic camera according to claim 1, further comprising a voltage detection circuit that detects a voltage of a battery that supplies power to the power supply circuit, the control circuit including the voltage detection circuit when the camera is powered on. An electronic camera characterized in that when the voltage detected by the detection circuit is equal to or lower than a predetermined value, the drive circuit is caused to perform the unnecessary charge discharging operation a plurality of times. 6. The electronic camera according to claim 1, wherein a light emission instruction detection circuit for detecting that a flash device is instructed to emit light, and a period from the release operation until the image pickup apparatus starts exposure. And a dimming circuit that detects reflected light from the preliminary light emitted from the flash device, and calculates a light emission amount of the flash device required after the start of exposure according to the reflected light amount, wherein the control circuit is When the light emission instruction is detected by the light emission instruction detection circuit, the drive circuit is caused to perform the unnecessary charge discharging operation a plurality of times, and the light emission amount is calculated while the unnecessary voltage discharging operation is inactive. An electronic camera characterized by controlling the dimming circuit as described above.