JP3345126B2 - Strobe device and still video camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strobe device capable of obtaining a more natural reproduced photographed image by adjusting the color temperature of the strobe light to the color temperature of the ambient light of a subject when photographing with a camera.

[0002]

2. Description of the Related Art In a conventional still video camera, white balance is adjusted so that a white object is photographed white regardless of the color temperature of illumination light on the object.
For example, in a still video camera equipped with a strobe device, by adjusting the gain of a color difference signal (RY, BY) or the like of a captured image output from a solid-state imaging device,
White balance adjustment is performed. When the light amount from the subject is insufficient, photographing with flash emission is performed, and the white balance adjustment in that case is controlled according to the color temperature of the flash light.

[0003] The color temperature of light emitted from a xenon tube used for an arc tube of a strobe device is close to daylight, and is higher than that of a general electric lamp such as a fluorescent lamp. For this reason, if such a white balance adjustment is performed on a subject having a general light, the white balance adjustment is not correctly performed on a captured and reproduced image of the subject that is out of the range where the strobe light cannot reach, resulting in a reddish tint. .

In order to prevent such unnatural colors from being reproduced in a part of the image, for example, white balance adjustment at the time of light emission of a strobe device may be performed.
A method has been proposed in which any one of a color temperature of strobe light, a color temperature of external light, and a color temperature intermediate between strobe light and external light is selected.

[0005]

However, even in the white balance adjustment performed by such a method, the white balance adjustment suitable for each of the subject portion irradiated with the strobe light and the subject portion not irradiated with the strobe light is not performed. Therefore, it is extremely difficult to realize good color reproduction over the entire photographing screen.

Then, a method is considered in which the color temperature of the strobe light is adapted to the color temperature of the ambient light of the subject under the shooting conditions. As a method of controlling the emission color temperature of such a strobe device, for example, two xenon tubes A and B each having a different type of filter are each caused to emit light a plurality of times, and the combined value of the color temperatures of the two xenon tubes is determined. A method of matching the color temperature of the ambient light of the subject can be considered. This is because the combined color temperature value of the strobe light from each of the xenon tubes A and B is always matched with the color temperature of the ambient light of the subject, and the light is emitted a plurality of times to obtain the desired light amount. Is what you do.

However, when such a plurality of xenon tubes emit light a plurality of times, the charge for generating a trigger signal of a trigger circuit that causes each of the xenon tubes to emit light is charged by a main capacitor used for generating flash light in the xenon tube. Since it is made by consuming electric charges, if it emits light more than once, the electric charge of the main capacitor will be consumed for generating the trigger signal, and the efficiency of converting the electric charges to strobe light will be poor, and it may not be possible to obtain a sufficient amount of light. Occurs.

On the other hand, a method of charging the main capacitor every time a flash is generated can be considered. However, charging the main capacitor during photographing requires a considerable amount of time. Make the shutter time longer. If the shutter time is long, camera shake may be caused, and good photographing may not be performed.

An object of the present invention is to provide a strobe device having a predetermined color temperature by synthesizing a plurality of flashes having different color temperatures, and to prevent a large amount of electric charge of a main capacitor from being consumed in the first light emission. Accordingly, it is an object of the present invention to provide a strobe device capable of preventing a color temperature from deviating from a target value due to a lack of charge in the next light emission and obtaining an appropriate exposure amount.

[0010]

A strobe device according to the present invention comprises: a light emitting means capable of emitting flashes having different emission color temperatures; a charge accumulating means for accumulating light-emitting charges of the light emitting means;
A colorimeter for measuring the color temperature of the ambient light; and determining a light emission ratio of the light emitting unit based on the color temperature to adjust the combined emission color temperature value of the entire light emitting unit to the color temperature of the ambient light. A light emission control unit that controls the start and stop of light emission of the light emission unit so as to prevent the emission color temperature combined value from deviating from the control target color temperature due to an increase in two light emission amounts.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a block circuit diagram of a still video camera to which a strobe device according to an embodiment of the present invention is applied. In this figure, a stop 40 is provided in front of the light receiving surface of the solid-state imaging device 38, and the amount of light received by the solid-state imaging device 38 from the subject 52 is adjusted. The light received by the light receiving surface of the solid-state imaging device 38 is converted into an electric signal corresponding to an image signal. An image sensor driving circuit 36 is connected to the solid-state image sensor 38, and image signals are sequentially read from the solid-state image sensor 38 by a shift pulse or the like generated by the image sensor driving circuit 36.

The R signal of the image signal photoelectrically converted by the solid-state imaging device 38 is amplified by an amplifier 35 and output to a signal processing circuit 34. Similarly, the B signal of the image signal is also amplified by the amplifier 33 and output to the signal processing circuit 34. The G signal of the image signal is directly input to the signal processing circuit 34 without passing through an amplifier. Amplifier 33, 3
Reference numeral 5 is connected to a control circuit 30. The control means 30 performs gain adjustment of the amplifier, that is, white balance control.

In the signal processing circuit 34, the image signal is converted into a recording signal of a predetermined format and output to the recording circuit 32. The image signal is sequentially recorded on a recording medium such as a magnetic disk (not shown) by the recording circuit 32.

This still video camera has a subject 52
Photoelectric conversion element that receives reflected light F3 from
For example, a photometric sensor 42 composed of a photodiode and a colorimetric sensor 50 composed of a plurality of photoelectric conversion elements having different spectral sensitivities of visible light are provided. The luminance of the subject 52 is measured by the photometric sensor 42, and the colorimetry is performed. Sensor 50
Thereby, the color temperature of the ambient light E1 of the subject 52 is measured. The color temperature information measured by the colorimetric sensor 50 is input to the control circuit 30. Based on the measured color temperature information, the amount of light emitted from each of the xenon tubes 10 and 12 is determined as described below.

The photometric sensor 42 is connected to an integrating circuit 44. The signal photoelectrically converted by the photometric sensor 42 is
The integration is performed according to the integration start signal S5 input from the control circuit 30. The integration circuit 44 is connected to the control circuit 30 via a comparison circuit 46, and a D / A converter 48 is connected to the comparison circuit 46. In the comparison circuit 46, D / A
The voltage value (signal S8) input from converter 48 and the integrated value input from integration circuit 44 are compared, and the comparison result is output to control circuit 30 as quench signal S6. Based on the quench signal S6, each xenon tube 1
Light emission of 0 and 12 is stopped.

A strobe device 70 is connected to the control circuit 30, and each of the xenon tubes 10, 1
The start and stop of the light emission of 2 are controlled by the control circuit 30. The strobe device 70 is a xenon tube 1 including a charging circuit 28 serving as a means for accumulating electric charges in the main capacitor 19 and a color temperature conversion filter 13 for changing the color temperature of strobe light.
2, a xenon tube 10 having no filter, a main capacitor 19 for storing light-emitting charges of the xenon tubes 10 and 12, and a trigger circuit 71 for generating a flash signal generation signal for each of the xenon tubes 10 and 12. And an insulated gate bipolar transistor (hereinafter referred to as IGBT) 2 serving as a switch means for starting and stopping light emission of each of the xenon tubes 10 and 12.
2 and 24.

In the strobe device 70, the charging circuit 28
The positive electrode of the main capacitor 19, the resistor 18, the xenon tube 10 and the anode terminal of the xenon tube 12 are connected to the signal line S12 from which the impulse voltage is output. The negative electrode of the main capacitor 19, the common terminal of the trigger transformer 14, and the emitter terminals of the IGBTs 22 and 24 are connected to a common ground signal line S10.
The low-voltage side coil of the trigger transformer 14 is connected to the other end of the resistor 18 via the trigger capacitor 16 and to the anode terminals of the diodes 20 and 26.

The cathode terminal of the diode 20 is connected to the cathode terminal of the xenon tube 10 and the collector terminal of the IGBT 22, and the cathode terminal of the diode 26 is connected to the cathode terminal of the xenon tube 12 and the collector terminal of the IGBT 24.

The base terminals of the IGBTs 22 and 24 are connected to a control circuit 30. The IGBTs 22 and 24 are controlled by light emission trigger signals S3 and S4 output from the control circuit 30.
Is turned on, and a current flows from the collector terminals of the IGBTs 22 and 24 to the emitter terminals. When the IGBT 22 is turned on, the IGBT 24 is connected to the O
When N is reached, the charge of the trigger capacitor 16 is discharged via the diode 26. Therefore, a current flows through the low voltage side coil of the trigger transformer 14 and a trigger pulse is induced in the high voltage side coil.

This trigger pulse is applied to the xenon tubes 10, 12
, And flash light is generated in the xenon tubes 10 and 12. That is, the diodes 20, 26
Is turned on for each xenon tube 1 by turning on each IGBT 22, 24.
0 and 12 function independently as rectifying elements for flashing.

The control circuit 30 includes a release switch 31 provided in the still video camera body and a timer circuit 5.
4 are connected, and various controls are performed by the control circuit 30 in accordance with the operation of the release switch 31. Lights F1 and F2 emitted from the xenon tubes 10 and 12 are emitted toward the subject 52.

Between the control circuit 30 and the charging circuit 28,
A charge start signal S2 for instructing the start of charge accumulation in the main capacitor 19, and a charge completion signal S for notifying the control circuit 30 that the predetermined charge accumulation in the main capacitor 19 has been completed.
1 is exchanged.

FIG. 2 shows a photometric sensor 42 composed of a photodiode or the like, an integrating circuit 44, and a comparing circuit 46.
And the connection state with the D / A converter 48. The integrating circuit 44 includes an operational amplifier 60, an integrating capacitor 64, and a reset switch 72. The photometric sensor 42 is connected between the inverted signal input terminal and the non-inverted input terminal of the operational amplifier 60. The non-inverting input terminal of the operational amplifier 60 is connected to a reference power supply 68 that supplies a reference voltage value before the start of integration.

Between the inverting input terminal and the output terminal of the operational amplifier 60, an integrating capacitor 64 and a reset switch 7
2 are connected in parallel, and the opening and closing of the contact of the reset switch 72 is controlled by the integration start signal S5 input from the control circuit 30. When the contact of the reset switch 72 is opened, the photometric sensor 42 is
Is integrated. The output terminal of the operational amplifier 60 is connected to the inverting input terminal of the comparison circuit 46.

The non-inverting input terminal of the comparison circuit 46 has a D / A
A converter 48 is connected, and a D / D
The voltage value of the output signal S8 of the A converter 48 and the operational amplifier 60
Is compared with the value of the output signal S7. When the voltage value of the signal S7 falls below the voltage value of the signal S8, the quench signal S
6 is output from the comparison circuit 46 to the control circuit 30. The voltage value of the signal S8 is transmitted from the control circuit 30 to the D / A converter 4
The voltage value of the signal S8 is determined by a proper integral value setting process described later.

The operation of this embodiment will be described. FIG. 3 is a sequence diagram showing an outline of flash light emission control in this embodiment.

When the release switch 31 is half-pressed (step D20), the object 5 is detected based on photometric data from a photometric sensor (not shown) different from the photometric sensor 42.
The light amount measurement of No. 2 is performed by the control circuit 30. Exposure calculation processing is performed in the control circuit 30 according to the photometric value (step D21).

In the exposure calculation processing, the operation time of the electronic shutter of the solid-state imaging device 38 and whether or not the flash device 70 needs to emit light are determined. The charging of the main capacitor 19 by the charging circuit 28 is performed when the main switch of the still video camera to which the present embodiment is applied is turned on, or when a switch (not shown) for instructing to perform flash photography is operated. Done in The charging process is also started at the time when the flash light emission control described later ends. The charging process is started when the control circuit 30 outputs a charging start signal S2 to the charging circuit 28.

In response to the input of the charge start signal S2, a pulse-like high voltage signal is output from the charging circuit 28 to the main capacitor 19, and the electric charge for flashing is sequentially accumulated in the main capacitor 19. When a predetermined charge is accumulated in the main capacitor 19, the potential of the signal line S12 reaches a predetermined value. Therefore, it is detected that the potential has reached the predetermined value, and the charge accumulation in the main capacitor 19 by the charging circuit 28 ends.

When the charge accumulation in the main capacitor 19 is completed, the charging circuit 28 sends a charge completion signal S to the control circuit 30.
1, that is, a signal indicating that the charge accumulation of the main capacitor 19 is completed. That is, the control circuit 30
In this case, it is recognized that strobe shooting is possible by input of the completion signal S1.

After the photometry and exposure calculation processing in step D21 is completed, when the release switch 31 is fully pressed (step D22), the control circuit 30 causes the colorimetric sensor 5
Using the signal value input from 0, the color temperature of the ambient light E1 is obtained (step D23). The ambient light E1 is composed of light from a light source located around the subject 52. By adjusting the amount of light emitted from each xenon tube according to the color temperature of the ambient light E1, the combined color of the strobe device 70 is obtained. The temperature is adapted to the ambient light E1, resulting in a more natural still photography.

The colorimetric sensor 50 is composed of at least two photoelectric conversion elements having different spectral sensitivity characteristics in the visible light region. The ratio of the output signals of the photoelectric conversion elements having different spectral sensitivities does not depend on the amount of received light and has a one-to-one relationship with the amount of received light. Therefore, the control circuit 30 calculates the color temperature of the ambient light E1 using the ratio of the output signals (or the logarithm of the ratio). The control circuit 30 stores a data table indicating a correspondence between a signal value input from the colorimetric sensor 50 and color temperature information in the signal value. Using this data table, the control circuit 30 calculates the color temperature of the ambient light E1 from the signal value input from the colorimetric sensor 50.

From the calculated color temperature information, an amplifier 33,
The gain of 35 is set by the control circuit 30 (step D24). That is, by adjusting the amplification amounts of the R signal and the B signal with respect to the G signal in accordance with the measured color temperature of the ambient light E1 of the subject 52, the white balance control of the image signal to be captured and recorded is performed. Is performed.

Next, based on the photometric value, the opening amount of the diaphragm 40 provided in front of the solid-state image sensor 38 is determined by the control circuit 30.
And the light amount of the light F4 from the subject 52 incident on the solid-state imaging device 38 is adjusted (step D2).
5). Then, based on the photometry result, the solid-state imaging device 38
, The shutter time is determined, and the charge accumulation is started (step D).
26).

The accumulation of the signal charges in step D26 is started, and if the strobe light emission by the light emitting device 70 is necessary based on the determination of the photometry result, the strobe light emission control described later is started (step D27). .
When the photographing with the flash emission is completed, the control circuit 3
Under the control of 0, a shift pulse is output from the image sensor driving circuit 36 to the solid-state image sensor 38.

With this shift pulse, the charge accumulation of the solid-state imaging device 38 is completed (step D28), and the aperture 40 is closed (step D29). Thereafter, a signal charge readout control signal such as a transfer pulse is output from the image pickup device drive circuit 36 to the solid-state image pickup device 38, and the signal charges accumulated in the solid-state image pickup device 38 are converted into image signals by the amplifiers 33 and 35 and the signal processing circuit 34. Are sequentially read and output (step D30).

The image signal output from the solid-state image pickup device 38 is converted into an image signal of a predetermined format by the signal processing circuit 34 and then recorded on a recording medium (not shown) by the recording circuit 32.

Strobe device 70 in step D27
Will be described in detail.

The color temperature of the strobe light of the xenon tube 12 is
It is reduced by the color temperature conversion filter 13. On the other hand, since the xenon tube 10 has no color temperature conversion filter, the emission color temperature of the xenon tube 10 is
2, which is higher than the strobe light color temperature. Therefore, by adjusting the amount of light emitted from each of the xenon tubes 10 and 12, the combined emission color temperature of the entire strobe device 70 can be matched with the measured color temperature.

For example, when the color temperature of the ambient light E1 is relatively high, the emission amount of the xenon tube 10 having a high color temperature of the strobe light is increased, and the emission amount of the xenon tube 12 having a low color temperature of the strobe light is increased. Control less. Conversely, when the color temperature of the ambient light E1 is relatively low, the light emission amount of the xenon tube 12 is controlled to be large, and the light emission amount of the xenon tube 10 is controlled to be small.

In determining the light emission amount ratio between the xenon tubes 10 and 12, the xenon tubes having a small light emission amount are controlled so as to emit light first. This is because, when a xenon tube emitting a large amount of light is emitted first, the light emitted from the xenon tube emitting a large amount of light consumes an extremely large amount of accumulated charge in the main capacitor 19, and the xenon tube between the anode and the cathode of the xenon tube to emit the light next time This makes it impossible to apply the potential difference required for flash generation.

The light-emission xenon tube is subjected to the dimming control described below. This dimming control means that the subject 5
In the flash photography performed when the brightness of 2 is low,
By adjusting the amount of light emitted from the xenon tube so that the amount of reflected light coming from the object 52 reaches a predetermined amount so that a good captured image can be obtained by the strobe light emitted from the strobe device 70 toward the object 52. is there. It is determined by the quench signal S6 input from the comparison circuit 46 whether or not the amount of light sufficient to obtain a good captured image signal has entered the solid-state imaging device 38 from the subject 52.

Therefore, when the distance from the still video camera to the subject 52 is long and the amount of strobe light reflected from the subject 52 is small, it is necessary to make each xenon tube emit light longer and more strongly.

Depending on the shooting conditions, the dimming control is performed, so that the amount of light emitted from the xenon tube that emits light first increases, and the accumulated charge in the main capacitor 19 may be consumed more. In this case, if more charge is consumed by the xenon tube that emits light first, there is a possibility that the xenon tube that emits light later cannot emit light or the amount of light emission becomes extremely short, as described above. As described above, when the amount of light emitted by the xenon tube that emits light is insufficient, the combined color temperature of the strobe device 70 does not reach the target value, and the color temperature of the strobe light is controlled to obtain a more natural photographed image. Is impaired.

Therefore, in order to prevent the electric charge of the main capacitor 19 from being consumed more by this dimming control, the emission time of the xenon tube which emits light first is limited. This light emission time restriction processing is shown in steps 100 to 112 of the flowchart of FIG. 4 described below.

FIG. 4 is a flowchart of the flash emission control of the flash unit 70 in step D27, which is executed by the control circuit 30. The flash emission control will be described with reference to FIG.

The amount of light emitted from a xenon tube is generally not proportional to the light emission time. Therefore, the maximum light emission time T which is a time limit for maintaining the light emission amount ratio A: B (A <B) of the xenon tubes 10 and 12 determined from the color temperature of the ambient light E1.
Are stored in a memory in the control circuit 30 as a data table corresponding to each color temperature. First, the maximum light emission time T corresponding to the xenon tube 10 is read from the data table in the memory in accordance with the measured color temperature of the ambient light E1, set in the timer circuit 54, and measured by the timer circuit 54. The operation starts (step 10
0). Light emission of the xenon tube 10 is forcibly stopped by a signal input from the timer circuit 54.

Next, in order to perform dimming control, the xenon tube 1
The appropriate integral value (digital data) corresponding to 0 is output to the D / A converter 48 (step 102). This proper integration value is a value corresponding to the light emission amount ratio A of the xenon tube 10. In the D / A converter 48, the appropriate integral value is converted into a signal S8 of an analog voltage value and output to the comparison circuit 46.

The reset signal S5 is input to the integration circuit 44, whereby the output of the integration value of the integration circuit 44 is reset (step 104). Then, the output of the reset signal S5 is stopped, the reset of the integrating circuit 44 is released, and the photocurrent generated by the photometric sensor 42 is temporally integrated by the operational amplifier 60 (step 106). The value of the photocurrent flowing through the photometric sensor 42 changes according to the illuminance of the reflected light F3 from the subject 52 received by the photometric sensor 42. By integrating this photocurrent value, the accumulated light amount of the reflected light F3 from the subject 52 is detected. Therefore, the integrated value output from the integrating circuit 44 represents the accumulated light amount of the reflected light F3.

When the integration circuit 44 starts measuring the accumulated light amount of the reflected light F3, a light emission trigger signal S3 is output to the IGBT 22 (step 108), whereby the IGBT 22 is turned on. As a result, the charge stored in the trigger capacitor 16 is transferred to the diode 20 and I
It flows toward the common ground signal line S10 via the GBT 22.

The discharge of the trigger capacitor 16 causes a current to flow through the low voltage side coil of the trigger transformer 14, and induces a high voltage through the high voltage side coil of the trigger transformer 14. Since the trigger voltage induced in the high-voltage side coil is applied to the trigger electrode of the xenon tube 10, the xenon tube 1
The xenon gas in 0 is ionized. Due to the ionization of the xenon gas, the resistance between the anode and cathode terminals sharply decreases, a spark current flows from the anode terminal to the cathode terminal to generate a flash, and the strobe light F1 is emitted toward the subject 52.

The reflected light F3 from the subject 52 is increased by the strobe light F1. When the output integrated value from the integration circuit 44 reaches the value of the signal S8 (proper integration value) or less due to the increase of the reflected light F3, the quench signal S6 is output from the comparison circuit 46. When the output of the quench signal S6 is confirmed in step 110, the output of the light emission trigger signal S3 stops, and the light emission of the xenon tube 10 stops (step 128).

In step 110, quench signal S6
Is not confirmed, it is determined whether or not the time elapsed by the timer circuit 54 has expired (step 112). If not, the process returns to step 110 and the output of the quench signal S6 is determined again. Is done. On the other hand, when the time is over, the output of the light emission trigger signal S3 is forcibly stopped (step 114). When the output of the light emission trigger signal S3 stops, the IGBT 22 is turned off, the current flowing through the xenon tube 10 is cut off by the IGBT 22, and the flash emission of the xenon tube 10 stops. IGBT22 OFF
Thus, the trigger capacitor 16 is quickly charged again.

Next, the timer circuit 54 is stopped (step 116), and the integration circuit 44 is reset (step 118). Then, the light emission trigger signal S4 is output (step 120), and the light emission start of the xenon tube 12 is controlled in the same manner as the xenon tube 10. That is, the IGBT 24 is turned on by the light emission trigger signal S4, and the charge of the trigger capacitor 16 is discharged by turning on the IGBT 24. And the trigger transformer 14
A trigger pulse is applied to the xenon tube 12, whereby the xenon tube 12 emits light.

By the light emission of the xenon tube 12, the electric charge of the main capacitor 19 is completely discharged, and the apparatus stands by for a period corresponding to the time when the light emission stops naturally (step 12).
2). This is because the light emission time of the xenon tube 10 has expired (YE in the determination of step 112).
S), unless the xenon tube 12 emits full light, the color temperature balance of the strobe light is lost. The charge remaining in the main capacitor 19 is completely consumed by the flash of the xenon tube 12, and after the lapse of the time when the flash stops naturally (the time when the full flash can be emitted), the light emission trigger signal S4
Is stopped (step 124).

As described above, even if the xenon tube 10 emits light during the maximum light emission time T, the xenon tube 12 is caused to emit full light with the residual charge, thereby reducing the emission color temperature of the entire strobe device 70 to the color temperature of the ambient light E1. Can be matched. FIG. 5 shows a state of light emission control by the processing of steps 100 to 124.

Thereafter, depending on the conditions, the charge start signal S
2 is output from the control circuit 30 to the charging circuit 28 again to prepare for the next new strobe light emission control.

On the other hand, if the input of the quench signal S6 is detected during the light emission of the xenon tube 10 (YES in step 110), the output of the light emission trigger signal S3 is stopped (step 128). Then, as in step 116, the timer circuit 54 is stopped (step 130), and the proper integration value (digital data) of the xenon tube 12 is set to D / A in order to perform dimming control for adjusting the light emission amount of the xenon tube 12. The result is output to the converter 48 (step 132). This proper integration value is determined based on the light emission amount ratio B of the xenon tube 12.

Then, the integration circuit 44 is reset (step 134), the integration operation of the integration circuit 44 is started (step 136), and the accumulated light amount of the reflected light F3 from the subject 52 is measured. At the same time as the integration of the integration circuit 44 is started, a light emission trigger signal S4 is output to the IGBT 24, and light emission of the xenon tube 12 is started. Then, it is monitored whether or not the quench signal S6 has been output (step 14).
0), when the quench signal S6 is output from the comparison circuit 46 (YES in step 140), the output of the light emission trigger signal S4 is stopped (step 142), and the light emission of the xenon tube 12 is stopped. Then, the integration circuit 44 is reset (step 144), and preparation for the next strobe light emission control is performed. The xenon tubes 10 and 12 emit light amount ratio A:
When B is greater than B, the maximum light emission time and the integrated value corresponding to the xenon tube 12 are set in steps 100 and 102 in FIG. 4, and the output order of the light emission trigger signal is reversed.

During the light emission of the xenon tube 10, the quench signal S
6 is output, that is, steps 100 to 144
FIG. 6 shows a state of light emission of the xenon tubes 10 and 12 by the above. As shown in this figure, the quench signal S6 is input to the control circuit 30 within the maximum light emission time T, and the maximum light emission time T
The light emission of the xenon tube 10 is stopped halfway.

As described above, even when the dimming control is performed satisfactorily, each appropriate integral value for controlling the light emission amount of each of the xenon tubes 10 and 12 is determined based on the light emission amount ratios A and B. Therefore, the combined color temperature of the strobe lights F1 and F2 can be adjusted to the measured color temperature of the ambient light E1, and an appropriate exposure can be obtained.

Further, according to the present embodiment, the light emission amounts of the two xenon tubes 10 and 12 are adjusted based on the measured color temperature information of the ambient light E1, and the light emission time of the xenon tube that emits light first is limited. Since the xenon tube that emits light first consumes a large amount of charge in the main capacitor 19, the charge for the xenon tube that emits light later becomes insufficient, and the combined color temperature of the entire strobe light may deviate from the target color temperature. Is prevented.

Further, according to the present embodiment, the trigger circuit 7
1. By using the xenon tubes 10 and 12 as the xenon tubes 10 and 12 for the charging circuit 28 and the main capacitor 19,
Despite increasing the number of xenon tubes for controlling the color temperature of the strobe light, the increase in the number of circuit components can be prevented as much as possible.
It is possible to prevent an increase in manufacturing cost and to maintain the reliability of the circuit.

FIG. 7 shows a second embodiment of the present invention.
In this figure, the same circuits as those in the first embodiment are denoted by the same reference numerals. The second embodiment differs from the first embodiment in that the amount of light emitted from the xenon tube that emits light first is limited based on the signal S20 input from the comparison circuit 47.

One input terminal of the comparison circuit 47 is connected to an intermediate contact between resistors 51 and 53 connected between the signal line S12 and the common ground signal line S10. The output signal of the D / A converter 49 is connected to the other input terminal of the comparison circuit 47. The input terminal of the D / A converter 49 is connected to the control circuit 30, and digital data corresponding to the comparison reference voltage value is input from the control circuit 30. On the other hand, the output terminal of the comparison circuit 47 is connected to the control circuit 30, and the comparison result of the comparison circuit 47 is a signal S.
20 is input to the control circuit 30.

The operation of the second embodiment will be described. FIG. 8 shows a processing flow of the present embodiment. When it is determined in the exposure calculation processing before this processing flow that flash photography is to be performed, the light emission ratio between the xenon tube 10 and the xenon tube 12 is changed to the ambient light E1 as in the first embodiment.
Is determined according to the measured color temperature.

By the way, the potential of the signal line S12 decreases due to the accumulated charge of the main capacitor 19 consumed by the light emission of the xenon tube which emits light first. Therefore, by stopping the xenon tube when the potential reaches a predetermined value, it is possible to prevent a shortage of electric charge for the xenon tube that emits light later, as in the first embodiment. Accordingly, it is possible to prevent the emission color ratio of the xenon tubes 10 and 12 from being collapsed and the combined color temperature of the entire strobe light from deviating from the target color temperature. In order to detect a decrease in the potential of the signal line S12, the potential of the signal S11 proportional to this potential is compared with the potential of the comparison circuit 4.
7 is monitored.

Even when the xenon tubes 10 and 12 emit light by consuming all the electric charge of the main capacitor 19,
In order to maintain the ratio of the light emission amount of these xenon tubes 10 and 12 at a value determined by the measured color temperature, the light emission of the signal S11 in which the light emission of the first xenon tube (for example, the xenon tube 10) must be stopped. The limit potential V1 is
It is obtained as follows.

The amount of light emitted from the xenon tube is determined by the main condenser 1
9 is not proportional to the charging voltage. Therefore, the emission limit potential V1 of the main capacitor 19 corresponding to the xenon tube 10 is
The data (data table) is stored in the memory of the control circuit 30 as data for each color temperature. Then, in accordance with the measured color temperature of the ambient light E1, the emission limit potential V1 for the xenon tube 10 is read from the data table in the memory and set in the D / A converter 49 (step 200). The digital data indicating the emission limit potential V1 is converted into an analog voltage by the D / A converter 49 and input to the comparison circuit 47.

Further, similarly to the first embodiment, the ambient light E1
The appropriate integrated value of the xenon tube 10 corresponding to the measured color temperature is output to the D / A converter 48. That is, data for performing light control is set in the D / A converter 48 (step 202). Then, the integration circuit 44 is reset, and measurement of the accumulated light amount of the reflected light F3 by the integration circuit 44 is started (steps 204 to 206).

At the same time as the integration of the integration circuit 44 is started, the light emission trigger signal S3 is output from the control circuit 30 to the IGBT 22, and the light emission of the xenon tube 10 is started (step 2).
08). When the amount of reflected light F3 by the integrating circuit 44 reaches an appropriate amount, the quenching signal S
6 is output (step 21).
0). Based on the output of the quench signal S6, the control circuit 30 stops the output of the light emission trigger signal S3 assuming that the appropriate amount of light has arrived from the subject 52, and the xenon tube 10
Is stopped (step 224).

On the other hand, when there is no input of the quench signal S6, it is determined whether or not the quench signal S20 has been output from the comparison circuit 47 (step 212). That is,
It is determined based on the signal S11 whether or not the potential of the signal S12 has reached the light emission limit potential V1.
Since the light emission of the xenon tube 10 cannot be performed any more, the output of the light emission trigger signal S3 is stopped to forcibly stop the light emission of the xenon tube 10 (step 21).
4).

Since the xenon tube 10 emits light to the emission limit, all the charges remaining in the main condenser 19 are consumed, and the xenon tube 12 emits light. After the integration circuit 44 is reset (step 216), the light emission trigger signal S4
Is output from the control circuit 30 to the IGBT 24. The light emission of the xenon tube 12 is started by the light emission trigger signal S4 (step 218).

The process waits until all the electric charges in the main capacitor 19 are consumed and the light emission of the xenon tube 12 becomes extremely weak (step 220). After that, the light emission trigger signal S4
Is stopped (step 222), and the state is shifted to a state where the main capacitor 19 can be charged in the new light emission control.

On the other hand, when the quench signal S6 is output during the light emission of the xenon tube 10 (step 2).
(YES in the judgment of 10), since the electric charge sufficient to cover the light emission of the xenon tube 12 remains in the main condenser 19, the proper operation of the xenon tube 12 is performed to perform the dimming control on the light emission of the xenon tube 12. The integrated value is output to the D / A converter 48 (Step 226).

Then, the integration circuit 44 is reset (step 228), the integration of the integration circuit 44 is started (step 230), and the dimming control of the xenon tube 12 is started based on the new proper integration value. When the integration of the integration circuit 44 starts, the light emission trigger signal S4 is transmitted from the control circuit 30 to the IGB.
The signal is output to T24, and light emission of the xenon tube 12 is started (step 232).

When the integration value of the integration circuit 44 becomes equal to the proper integration value, the quench signal S6 is output from the comparison circuit 46 (step 234), and the output of the light emission trigger signal S4 is stopped (step 236). 44 is reset (step 238).

As described above, in the second embodiment, in order to prevent the electric charge of the main condenser 19 from being consumed more by the light emission amount of the xenon tube which emits light first, the light emission amount of the xenon tube which emits light first is limited. Is provided. This limiting means includes a light emission limit potential determined by a light emission ratio of each xenon tube in which the potential of the signal line S12, which is reduced by the charge of the consumed main capacitor 19, that is, the potential of the signal S11 is determined by the color temperature of the ambient light E1. Performed when they are equal.

Therefore, the xenon tube that emits light first consumes more charge of the main condenser 19, the amount of light emitted by the xenon tube that emits light less than the target amount, and the combined color temperature of the entire strobe device 70 deviates from the target value. Is prevented.

The emission waveforms of the xenon tubes 10 and 12 whose emission is controlled by the loop of steps 200 to 238, the quench signals S6 and S20, the potential of the signal line S12,
That is, the state of the voltage change of the divided main capacitor 19 is shown in FIGS. FIG. 9 shows a case where the quantity of reflected light F3 from the subject 52 is large, the quench signal S6 is input to the control circuit 30 by the dimming control, and the light emission of the xenon tube 10 is stopped. FIG.
2 when the reflected light F3 is small and the quench signal S6 is not input to the control circuit 30 due to dimming control;
The case where NO is determined in step 210 of FIG. 8 and then steps 212 to 222 are performed is shown.

As described above, in each embodiment, a plurality of xenon tubes having different emission color temperatures are provided, and the emission amount ratio of each xenon tube is determined so as to match the color temperature of the ambient light of the subject. Then, based on this light emission amount ratio, the xenon tube with the smaller light emission amount emits light first, and the dimming control consumes a large amount of electric charge of the main capacitor by the xenon tube, so that the xenon tube that emits light later has enough light. A means is provided for limiting the amount of light emitted from the xenon tube that emits light first so that the supply of an unusual charge falls into an impossible state and the combined emission color temperature of all xenon tubes does not deviate from the color temperature of ambient light.

In the first embodiment, a means for limiting the time by means of time measurement such as a timer circuit 54 is used as the limiting means. In the second embodiment, the charge of the main capacitor 19 which is reduced by the light emission of the xenon tube is used. Means for limiting the voltage according to the voltage applied to each xenon tube is used. By such a limiting means, it is possible to prevent a large amount of electric charge of the main capacitor from being consumed by the xenon tube that emits light first, and as a result, to completely prevent the combined color temperature of the entire flash device from deviating from the target color temperature. it can.

Further, in each embodiment, the main capacitor 1
Since the xenon tubes share the charging circuit 28 for storing the charge of the capacitor 9 and the main capacitor 19, the increase in the number of components due to the provision of a plurality of xenon tubes can be suppressed as much as possible. The mounting space can be saved, the weight of the entire apparatus can be reduced, and the reliability of the entire apparatus due to the reduction in the number of components can be improved.

In order to adjust the composite color temperature by causing each of the plurality of xenon tubes to emit light in multiple stages for a short period of time, a trigger pulse to be applied to the xenon tubes is generated at the start of repeated light emission of each xenon tube. The charge of the capacitor is consumed, and the charge of the main capacitor used for flashing decreases. However, in each of the above embodiments, since each xenon tube emits light only once, it is possible to prevent the charge of the main capacitor from being wasted as in the case of generating a trigger pulse.
The electric charge of the main capacitor can be efficiently used for strobe light.

The number of xenon tubes is not limited to two, but may be larger. For example, three xenon tubes and R, G, and B color filters are attached to each xenon tube, and the emission color temperature of each xenon tube is set to a three-step difference, and finer color temperature control of strobe light is performed. It may be performed. In this case, the amount of light emission is limited to the first and second
This is performed for the xenon tube that emits light the second time. That is, when adjusting the combined color temperature by providing N xenon tubes as light emitting means, the amount of light emission is limited for each xenon tube that emits light from the first to the (N-1) th. Note that the maximum light emission amount limitation by the limitation means may be added to all N pieces.

Further, in each of the above embodiments, the IGBT 2 is used as a switch for controlling the emission / stop of each xenon tube.
Although 2, 24 are used, this may be performed using a plurality of thyristors. The means for measuring the strobe reflected light from the subject 52 and the means for generating a quench signal are not limited to the operational amplifier and the analog comparator as shown in FIG.
A comparison circuit may be configured.

As the reflected light from the subject to be incident on the photometric sensor 42 and the colorimetric sensor 50, a part of the light passing through the taking lens system provided in the solid-state image sensor 38 may be used. With such a configuration, the solid-state imaging device 38
Can be measured more accurately.

Further, in each of the above embodiments, the main capacitor 19 and the trigger circuit 71 are connected to the xenon tubes 10 and 12 respectively.
IGBTs, which are switching means for turning on and off the xenon tubes 10 and 12, are provided independently for each xenon tube. However, the switching means is shared for each xenon tube, and the trigger circuit and the main capacitor are provided for each of the xenon tubes. The trigger circuit may be independently provided on the xenon tube so that ON and OFF of the trigger circuit can be independently performed according to a control signal from the control circuit 30. When it is desired to emit light from any of the xenon tubes, the common switch is turned on, and a control signal is output from the control circuit 30 to a trigger circuit provided in the xenon tube to emit light. Only to apply a trigger pulse to cause light emission. The light emission of the xenon tube can be stopped by turning off the switch means.

Thus, the light emission of a plurality of xenon tubes can be controlled independently by a plurality of trigger circuits, and the emission and stop of each xenon tube can be alternately repeated. As a further application, the switch means and the trigger circuit may be independently provided for each xenon tube.

In the first and second embodiments, the still video camera has been described.
The present invention can be applied to a strobe device including the colorimetric sensor 50, the photometric sensor 42, and the like. That is, if the present invention is applied to a strobe device without a still video photographing circuit such as the solid-state imaging device 38, the signal processing circuit 34, and the recording circuit 32, it can be used in a conventional still camera.

FIG. 11 is a block circuit diagram of a still video camera to which a strobe device according to a third embodiment of the present invention is applied. In the third embodiment, only one xenon tube is provided, and two types of color temperature conversion filters 56A and 56B are provided in front of the light projecting surface of the xenon tube 12 so that they can be moved alternately. . As will be described later, by switching these filters 56A and 56B, the emission color temperature changes, and the overall composite color temperature of the strobe device is controlled.

The strobe device includes, in addition to the xenon tube 12, a main capacitor 19 for storing light-emitting charges of the xenon tube 12, a booster circuit 28 as a means for accumulating charges in the main capacitor 19, and a flash of the xenon tube 12. A trigger circuit 71 for generating a trigger signal for generation, and a xenon tube 1
IGBT as switch means for starting and stopping light emission
22, a voltage dividing resistor R1, R2 for measuring the output voltage of the main capacitor 19, and an A / D converter 53 for measuring a voltage value at an intermediate connection point between the resistors R1, R2. .

The signal line S12 from which the impulse voltage is output from the booster circuit 28 is connected to the positive electrode of the main capacitor 19, one ends of the resistors R1 and R18, and the anode terminal of the xenon tube 12. The negative electrode of the main capacitor 19, the common terminal of the trigger transformer 14, and the IGBT
The emitter terminal 22 and one end of the resistor R2 are connected to a common ground signal line S10. The low voltage side coil of the trigger transformer 14 is a trigger capacitor 16
Connected to the other end of the resistor 18 via the IGB
It is connected to the collector terminal of T22.

The point where the resistors R1 and R2 are connected is connected to the A / D converter 53. The output terminal of the A / D converter 53 is connected to the control circuit 30,
The digital data S16 output from the D converter 53 is input to the control circuit 30.

The base terminal of the IGBT 22 is connected to the control circuit 30
It is connected to the. The IGBT 22 is turned on by the light emission trigger signal S3 output from the control circuit 30, whereby a current flows from the collector terminal of the IGBT 22 to the emitter terminal. That is, the charge of the trigger capacitor 16 is discharged, a current flows through the low voltage side coil of the trigger transformer 14, and a trigger signal is induced in the high voltage side coil. This trigger signal is applied to the trigger electrode of the xenon tube 12, and as a result, a flash is generated by the xenon tube.
Is projected toward the subject 52.

FIGS. 12 to 14 show the structure of a strobe device 70 provided in this embodiment. 13 and 14 are horizontal cross-sectional views of the strobe device 70 taken along the line XX in FIG.

As shown in these figures, the strobe device 7
The xenon tube 12 is mounted in an opening 58 located at the center of the xenon 0, and a reflector 65 is provided on the rear side of the xenon tube 12. Color temperature conversion filters 56A and 56B are provided between the reflector 65 and the opening 58, and these color temperature conversion filters 56A and 56B are fixed to the slider 64.

The color temperature conversion filter 56A is a xenon tube 1
2, the color temperature conversion filter 56B is a filter having the function of lowering the emission color temperature of the xenon tube 12. Note that the color temperature conversion filter 56A may be a transparent filter.

A gear is provided on one side of the slider 64, and this gear meshes with a gear 62 provided on the output shaft of the motor 61. By the forward / reverse rotation of the motor 61,
The color temperature conversion filters 56A and 56B are moved in front of the reflector 65. The motor 61 is a motor drive circuit 59
The motor drive circuit 59 is connected to the control circuit 30.
Is connected to Based on a command from the control circuit 30, the motor driving circuit 59 rotates the motor 61 forward and backward, and switches the color temperature conversion filters 56A and 56B disposed in front of the reflector 65.

The other structure is the same as in the first and second embodiments.

FIGS. 15 and 16 show a flowchart of flash emission control in the third embodiment. In the color measurement process before the strobe light emission control, the emission ratio A: B of the xenon tube 12 performed using the color temperature conversion filters 56A and 56B is determined according to the measured color temperature of the ambient light E1. That is, the light emission amount of the xenon tube 12 performed when the color temperature conversion filter 56A is disposed in front of the light emitting surface,
The ratio between the amount of light emitted from the xenon tube 12 and the amount of light emitted from the xenon tube 12 when the color temperature conversion filter 56B is disposed in front of the light emitting surface is determined according to the color temperature of the ambient light E1.

Then, using the digital data S16 input from the A / D converter 53, the initial charging voltage value (the charging voltage at the time of shutter release) of the main capacitor 19 is detected. The detected initial charging voltage value is temporarily stored in the memory (step 300).

The motor 61 is driven so that the color temperature conversion filter corresponding to a smaller ratio among the light emission ratios A and B is located in front of the light emitting surface of the xenon tube 12 (step 302). For convenience of explanation, the light emission ratio A: B determined from the color temperature of the ambient light E1 is set to A <B. Therefore, the xenon tube 12
Is moved before the color temperature conversion filter 56A. vice versa,
If A> B, the color temperature conversion filter 56B is moved before the xenon tube 12, and the following setting processing is performed.

Next, an appropriate integral value M of the xenon tube 12 with respect to the measured color temperature of the ambient light E1 is set in the D / A converter 48 (step 304). This proper integration value M is a threshold value for obtaining an optimal captured image by dimming control.

The maximum light emission time corresponding to the maximum light emission amount of the xenon tube 12 using the color temperature conversion filter 56A while maintaining the light emission ratio A: B is determined by the main capacitor 19
, And is set in the timer circuit 54 (step 306).

The maximum light emission time is obtained by using a data table stored in the memory of the control circuit 30. The data table stores data of each maximum light emission time capable of holding the light emission ratio A: B based on the detected initial charge voltage value of the main capacitor 19.

After the processing in step 306, the timer circuit 5
4 starts (step 308), and after the integration circuit 44 is reset by the reset signal S5 (step 3).
10), integration of the integration circuit 44 is started (step 3)
12). Thus, the dimming control based on the accumulated light amount of the reflected light F5 is started.

When the integration of the integration circuit 44 is started, a light emission trigger signal S3 is output, and light emission of the xenon tube 12 is started (step 314). Thereafter, the control circuit 30 determines whether or not the quench signal S6 for performing the dimming control has been input (step 316). When the quench signal S6 is input to the control circuit 30, the output of the light emission trigger signal S3 is stopped, and the light emission of the xenon tube 12 is stopped (step 320).

On the other hand, when the quench signal S6 is not input, the control circuit 30 determines whether or not the time-over signal S14 is input from the timer circuit 54 (step 318). This time-over signal S14 is
This indicates that the elapsed time from the start of light emission has exceeded the maximum light emission time. If the time-over signal S14 is not input, the process returns to the determination of step 316. Time-over signal S
If 14 has been input, the output of the light emission trigger signal S3 is stopped, and the light emission of the xenon tube 12 is stopped (step 320).

Then, the timing operation of the timer circuit 54 is stopped (step 322). Next, a filter having a large emission ratio, here the color temperature conversion filter 56B, is moved to the front of the xenon tube 12 by driving the motor 61 (step 324).

In order to control the dimming of the xenon tube 12 with the color temperature conversion filter 56B, an appropriate integral value N obtained from the measured color temperature of the ambient light E1 is set in the D / A converter 48 (step 326). The maximum light emission time for the color temperature conversion filter 56B is read from the data table from the light emission ratio A: B determined from the measured color temperature and the initial charge voltage value of the main capacitor 19, and is set in the timer circuit 54. (Step 328).

After the timer circuit 54 is started (step 330) and the integration circuit 44 is reset (step 332), the integration of the integration circuit 44 is started (step 334). Then, the light emission trigger signal S3 is output, and the light emission of the xenon tube 12 is started again (step 33).
6).

Thereafter, it is determined whether the quench signal S6 is input from the comparison circuit 46 and whether the time-over signal S14 is input from the timer circuit 54 (step 33).
8, 340). When the quench signal S6 or the time-over signal S14 is input, the output of the light emission trigger signal S3 is stopped (step 342), and the light emission of the xenon tube 12 is stopped. And the timer circuit 54
Is stopped (step 346).

When the strobe light emission control is completed as described above, the signal charges accumulated in the solid-state image pickup device 38 are read out as image signals, and are converted into image signals of a predetermined format by the signal processing circuit 34. Recording circuit 32
Is recorded on a recording medium (not shown). Thereafter, the charge start signal S2 is output from the control circuit 30 to the booster circuit 28 again according to the conditions, and preparation for the next new strobe light emission control is performed.

As described above, in the third embodiment, one filter increases the color temperature of the transmitted light, and the other filter reduces the color temperature of the transmitted light.
A and 56B are provided in front of the xenon tube 12 so that they can be exchanged and moved, and the light emission amount of the xenon tube 12 when the color temperature conversion filter 56A is in front of the light projection surface and the color temperature conversion filter 56B are in front of the light projection surface. The ratio of the amount of light emitted from the xenon tube 12 at that time is determined from the color temperature of the ambient light E1 of the subject 52, and the combined color temperature of the entire flash device 70 is adjusted.

Further, in the third embodiment, in order to prevent the amount of light emitted from one of the light-emitting elements from being excessively increased by the dimming control, the main condenser is connected to the light-emitting time of the xenon tube 12 in each of the color temperature conversion filters 56A and 56B. Restrictions were made based on the 19 initial charging voltage values and the color temperature of ambient light E1. As a result, it is possible to prevent the light emission amount of the xenon tube from increasing when one of the color temperature conversion filters is used by the dimming control, and to obtain a more natural photographed image.

In the third embodiment, two types of color temperature conversion filters are provided, but three or more types of color temperature conversion filters may be used. Further, a liquid crystal cell having an electric field control birefringence effect capable of changing the hue of transmitted light depending on the applied voltage may be fixed in front of the xenon tube 12 as a color temperature conversion filter. In this case, a voltage control means for changing a voltage value applied to the liquid crystal cell is used instead of the motor 61 and the motor drive circuit 59. That is, the color temperature of the transmitted light is controlled by changing the voltage value applied to the liquid crystal cell when the light emission ratio A emits light and the voltage value applied to the liquid crystal cell when the light emission ratio B emits light. Thereby, the combined color temperature of the strobe device 70 can be freely controlled.

[0118]

As described above, according to the present invention, a large amount of electric charge of the main capacitor is prevented from being consumed in the first light emission, and the color temperature is reduced to the target value due to insufficient electric charge in the next light emission. This can provide the effect of preventing deviation from the position and obtaining an appropriate exposure amount.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a first embodiment of a still video camera to which the present invention is applied.

FIG. 2 is a detailed diagram of a photometric sensor, an integration circuit, and a comparison circuit.

FIG. 3 is a timing chart showing a photographing operation of the first embodiment.

FIG. 4 is a flowchart illustrating an operation of flash photography in the first embodiment.

FIG. 5 is a light emission waveform diagram at the time of light emission of each xenon tube with respect to a light emission trigger signal in the first embodiment.

FIG. 6 is a light emission waveform diagram at the time of light emission of each xenon tube in response to a light emission trigger signal in the first embodiment.

FIG. 7 is a circuit diagram of a still video camera according to a second embodiment of the present invention.

FIG. 8 is a flowchart showing a flash photography operation in the second embodiment.

FIG. 9 is a light emission waveform diagram at the time of light emission of each xenon tube in response to a light emission trigger signal in the second embodiment.

FIG. 10 is a light emission waveform diagram at the time of light emission of each xenon tube with respect to a light emission trigger signal in the second embodiment.

FIG. 11 shows a third still video camera to which the present invention is applied.
It is a circuit diagram of an example.

FIG. 12 is a front view of a strobe device according to a third embodiment.

FIG. 13 is a sectional view of a strobe device according to a third embodiment.

FIG. 14 is a sectional view of a strobe device according to a third embodiment.

FIG. 15 is a flowchart of flash emission control according to the third embodiment.

FIG. 16 is a flowchart of flash emission control according to the third embodiment.

DESCRIPTION OF SYMBOLS 10, 12 Xenon tube 14 Trigger transformer 16 Trigger capacitor 19 Main capacitor 22, 24 IGBT 28 Charging circuit 30 Control circuit 38 Solid-state image sensor 42 Photometric sensor 44 Integrating circuit 46, 47 Comparison circuit 50 Colorimetric sensor 52 subject

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03B 15/04-15/05 H04N 9/04

Claims (4)

(57) [Claims] 1. A light emitting means capable of sequentially emitting flashes having different emission color temperatures, and a single light emitting means for accumulating light emission charges of the light emitting means.
One charge accumulating unit, a colorimetric unit for measuring a color temperature of ambient light, and a light emission amount ratio of the light emitting unit is determined based on the color temperature, and a combined emission color temperature value of the entire light emitting unit is converted into a color of the ambient light. Light emission for adjusting the temperature and controlling the start and stop of light emission of the light emitting means so as to prevent at least one light emission amount of the light emitting means from increasing and the emission color temperature combined value from deviating from the control target color temperature. Control means, wherein the light emission control means first emits a flash having a relatively small light emission amount among a plurality of flashes emitted by the light emitting means.
Is light and flash device in which light amount of flash light for emitting first is characterized in that to fully emit flash light to emit light when it exceeds a predetermined value, after. 2. A light emitting means capable of sequentially emitting flashes having different emission color temperatures, and a single light emitting means for accumulating a light emitting charge of the light emitting means.
One charge accumulating unit, a light amount measuring unit that measures the amount of light from the subject, a color measuring unit that measures the color temperature of ambient light, and a light emitting unit that adjusts a combined color temperature of the entire light emitting unit to the color temperature. A means for setting a maximum light emission time, which is a time limit for maintaining the light emission amount ratio, and maintaining the light emission amount ratio, and starting and stopping light emission of the light emitting unit according to the light amount measured by the light amount measuring unit. controlling, in a plurality of flash light emitted by said light emitting means, light emission quantity of the relative
A flash control device for causing the first flash to emit a very small amount of flash light, and for fully emitting the second flash light when the amount of flash light emitted first exceeds the maximum light emission time. . 3. A light emitting means capable of sequentially emitting flashes having different light emitting color temperatures, and a single light emitting means for accumulating light emission charges of the light emitting means.
One charge accumulating unit, a light amount measuring unit that measures the amount of light from the subject, a color measuring unit that measures the color temperature of ambient light, and a light emitting unit that adjusts a combined color temperature of the entire light emitting unit to the color temperature. Means for determining a light emission amount ratio, setting a light emission limit potential which is a limiting voltage for maintaining the light emission amount ratio, and controlling start and stop of light emission of the light emitting unit in accordance with a measured light amount by the light amount measuring unit. In the plurality of flashes emitted by the light emitting means , the amount of emitted light is relatively small.
Light emission control means for emitting a small amount of flash light first, and when the light emission amount of the charge storage means corresponding to the flash light emitted first becomes lower than the emission limit potential, causing the flash light emitted later to emit full light. A strobe device comprising: 4. A strobe device according to claim 1, further comprising an image pickup device for converting a subject image into an image signal.
A still video camera, wherein an amplification degree of an image signal output from an image sensor is adjusted according to a color temperature measured by the color temperature measuring means.