JP2000321633A - Electronic flash device and camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a contribution to miniaturization and cost reduction and to enable adequate photographing by suppressing the occurrence of variation in stop accuracy. SOLUTION: A control means 23 of this electronic flash device is provided with a full charging voltage value and at least >=1 charging stop voltage value lower than the full charging voltage value as the charging voltage value of a main capacitor 22 for supplying electric charges to a flash discharge tube 21 and outputs control signals to boosting means 3 to 11 for charging the main capacitor 22 to the high voltage by boosting the voltage of a power source 1 and discharging means 17 to 19 for discharging the electric charges charged in the main capacitor 22 in such a manner that the detected values of detecting means 13 to 16 for detecting the potential of the electric charges charged in the main capacitor 22 attain the values meeting photographing conditions, thereby changing the charging voltage value of the main capacitor 22 to either of the full charging voltage value or the charging stop voltage value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a strobe device and a camera provided with the strobe device.

[0002]

2. Description of the Related Art In recent years, in the field of photographic cameras, not only ordinary cameras but also so-called compact cameras have been zoomed, and recently, products having a zoom magnification exceeding 4 times have appeared. At the same time, the strobe device built into the camera has been increasing in guide number.

For example, in a flash device, a zoom method has been adopted in which the angle of view is varied according to the focal length of a photographic lens of a camera, and in the telephoto direction, the irradiation angle is narrowed to increase the guide number. Further, in the flash device, such a zooming operation allows the open FNo. FNo. FNo. 4 on the tele side. There are more than 10 models.

In such a strobe device, if the strobe reach distance on the telephoto side is extended, the aperture stop on the wide side will have a considerably small aperture diameter (small aperture), and the aperture accuracy will vary, and ambient light cannot be expected. , The thyristor or IGBT (in
luminous intensity is controlled by an element such as an insulated gate bipolar transistor).
Is often used in combination with a dimming circuit that changes the value of

[0005] Further, in the conventional strobe device, when the reach of the strobe is extended, a small aperture is used during close-up photography such as macro photography, and the aperture precision varies, so that a dimming method or the like is often used. .

[0006]

However, if such a zooming or dimming circuit is employed in a strobe device built in a camera, the camera becomes large in size both mechanically and in mounting components. This has the disadvantage that the portability of the camera is impaired and that the cost increases.

The present invention has been proposed in view of the above-mentioned problems, and contributes to downsizing and cost reduction, and suppresses the occurrence of variations in aperture accuracy, thereby enabling appropriate photographing. It is an object of the present invention to provide a device and a camera provided with the electronic flash device.

[0008]

SUMMARY OF THE INVENTION An electronic flash device and a camera according to the present invention, in order to solve the above-mentioned problems, include a light emitting means having a flash discharge tube, a main capacitor for supplying electric charge to the flash discharge tube, and a power supply voltage. Boosting means for boosting the main capacitor to a high voltage, detecting means for detecting the potential of the electric charge charged in the main capacitor, discharging means for discharging the electric charge of the main capacitor, and detecting means for detecting Control means for controlling the operation of the boosting means and the discharging means based on the value, and controlling the light emitting means so as to supply the electric charge charged in the main capacitor to the flash discharge tube. As the charge voltage value, a full charge voltage value and at least one or more charge stop voltage values lower than the full charge voltage value are provided so that the detection value of the detection means becomes a value according to the imaging condition. By outputting a control signal to the booster means and discharging means, the charging voltage of the main capacitor, switching to either a full charge voltage value or the charging stop voltage.

In the electronic flash device and the camera, the charging voltage value of the main capacitor is switched to either the full charging voltage value or the charging stop voltage value in accordance with the photographing conditions, so that the main capacitor supplied to the flash discharge tube. The charge amount of the capacitor is switched.

[0010]

FIG. 1 shows a first embodiment of the present invention. FIG. 1 is a circuit configuration diagram of a camera provided with the electronic flash device of the present invention, and the circuit of a so-called strobe built-in camera is extracted and shown. In FIG. 1, reference numeral 1 denotes a battery serving as a power supply, and 2 denotes an electrolytic capacitor. The electrolytic capacitor 2 is connected to the battery 1 in parallel. 3 is resistance,
Reference numeral 4 denotes a capacitor, and reference numeral 5 denotes an oscillation transistor. A parallel circuit of the resistor 3 and the capacitor 4 is connected between the base and the emitter of the oscillation transistor 5. 6 is a resistor, 7 is a switch element, 8 is a diode, the resistor 6 is connected between the control electrode of the switch element 7 and the negative electrode of the battery 1, and the switch element 7 is connected between the base of the oscillation transistor 5 and the cathode of the diode 8. .

An oscillation transformer 9 has a primary winding (P) between the collector of the oscillation transistor 5 and the negative electrode of the battery 1 and an intersection of the secondary winding (S) and the feedback winding (F) connected to the diode 8. It is connected to the intersection of the cathode and the switch element 7. The other end of the feedback winding (F) is connected to the negative electrode of the battery 1 via the resistor 10. A capacitor 11 is connected in parallel to the secondary winding (S) of the oscillation transformer 9.

Reference numeral 12 denotes a rectifying diode. Reference numeral 22 denotes a main capacitor. The cathode of the rectifying diode 12 is connected to the positive electrode of the main capacitor 22, and the negative electrode of the main capacitor 22 is connected to the negative electrode of the battery 1. Reference numerals 13 and 16 denote voltage dividing resistors, 14 denotes a switching element, and 15 denotes a resistor, and these constitute a voltage detecting circuit. In the voltage detection circuit, the voltage dividing resistor 1
3, a series circuit including the switch element 14 and the voltage dividing resistor 16 is connected to the main capacitor 22. The resistance 15
Is connected between the control electrode of the switch element 14 and the negative electrode of the battery 1.

17 is a discharge resistor, 18 is a switch element, 1
Reference numeral 9 denotes a resistor, which constitutes a discharge circuit. In the discharge circuit, a series circuit including a discharge resistor 17 and a switch element 18 is connected to the main capacitor 22, and a resistor 19 is connected between a control electrode of the switch element 18 and a negative electrode of the battery 1.

Reference numeral 20 denotes a light emitting circuit, and reference numeral 21 denotes a flash discharge tube, which is connected so that the output of the light emitting circuit 20 is applied to a transparent electrode of the flash discharge tube 21. In the camera with a built-in strobe shown in FIG. 1, a strobe device is constituted by the above circuits. In the strobe device, charging of the main capacitor 22 and light emission of the flash discharge tube 21 are controlled by a control circuit 23 described later.

Hereinafter, each circuit on the camera side will be described. Reference numeral 23 denotes a control circuit arranged on the camera side, for example.
As shown in FIG. 1, it is composed of an I / O control circuit, an A / D converter, a multiplexer, a microcomputer (hereinafter abbreviated as a microcomputer) and the like.

Reference numeral 30 denotes a constant voltage circuit.
Supplies a power supply Vcc and a reference voltage Vbat to each circuit. Reference numeral 31 denotes a switch circuit for detecting a camera switch. The switch circuit 31 is connected to the control circuit 23 via the SWD terminal, and is turned on when a power switch (not shown) and a release (shutter) button are half-pressed. A signal indicating the state of various switches such as the first stroke switch SW1 and the second stroke switch SW2 of the release button is output to the control circuit 23.

Reference numeral 32 denotes a film sensitivity detection circuit for detecting film sensitivity and the like. Reference numeral 33 denotes a display circuit for displaying the number of shot frames, the mode, and the like, and is connected to the control circuit 23 via a DISP terminal. 34 is a photometric circuit for detecting the brightness of the subject, 35 is a distance measuring circuit for measuring the distance to the subject, 36 is a lens drive circuit for driving a lens, and 37 is a film wind-up and rewind drive. And 38, a shutter circuit for driving a shutter.

Note that each of the terminals a to e in FIG. 1 is a connection terminal between the control circuit 23 and the strobe device.
The switch elements 7, 14, and 18 are respectively n-ch F-channels.
ET is used, and when a high-level signal is supplied to the control electrode of the gate, the ET is turned on, that is, turned on.

Next, the operation of the camera with a built-in strobe having such a configuration will be described.

In a camera with a built-in strobe, when the battery 1 is inserted, the control circuit 23 of the camera enters a low power consumption mode and stops operating. From this state, the control circuit 23 starts operating when a power switch in the switch circuit 31 that is linked with a member such as a barrier of the camera is turned on. For cameras with built-in flash, control circuit 2
3 supplies a signal to the constant voltage circuit 30 via the VccEN terminal, so that the constant voltage circuit 30 supplies the reference voltage Vbat and the power supply Vcc to each circuit.

The subsequent operation will be described in detail with reference to the flowchart of FIG. The control circuit 23 determines in step S
In step 1, necessary initial settings for the microcomputer are made, and the next step S
After controlling the constant voltage circuit 30 to supply the power supply Vcc to the switch circuit 31 in step 2, the process proceeds to step S3.

In step S3, the control circuit 23 detects the state of the switch SW1 of the first stroke described above,
It is determined whether the switch SW1 is on.
If it is determined that the switch SW1 is ON, that is, the release button is half-pressed, the process proceeds to step S4.
When it is determined that the release button is not pressed, that is, when the release button is not pressed, the process returns to step S2, and the above-described processing in steps S2 and S3 is performed until the release button is determined to be half-pressed. repeat.

If it is determined that the release button is half-pressed, the control circuit 23 resets a predetermined counter in the microcomputer to an initial state in step S4, and then proceeds to step S5.
A battery check is performed on the battery 1 at step S.
Move to 6. The control circuit 23 determines in step S6 that the battery 1
It is determined whether or not the camera is in a power supply state required for shooting by the camera. If it is determined that the camera is in a necessary power supply state, the process proceeds to step S7. If it is determined in step S6 that the camera is not in a necessary power supply state, The control circuit 23 controls the display circuit 33 via the DISP terminal to display on the display circuit 33 that the battery 1 needs to be replaced, and returns to step S2.

In step S7 when it is determined that the battery 1 is in a power state necessary for photographing by the camera, the control circuit 23 supplies a signal to the AFC terminal. As a result, the distance measurement circuit 35 operates to measure the distance to the subject, and the distance measurement information (AF data) from the distance measurement circuit 35 which is a measured value.
Is input to the control circuit 23 via the AFD terminal.

In the following step S8, the control circuit 23
Apply a signal to the AEC terminal. Thereby, the photometric circuit 34
Is operated to measure the luminance of the object, and the luminance information from the photometric circuit 34, which is the measured value, is transmitted to the control circuit 2 via the SP terminal.
3 is input.

In the next step S9, the control circuit 23
From the luminance information input from the photometry circuit 34, it is determined whether the measured luminance is brighter or darker than a predetermined luminance. If the luminance is determined to be dark, the subject is dark and a flash is required, and the process proceeds to the flash mode of step S10. If it is determined that the brightness is high, it is determined that the flash is not necessary, and the process proceeds to step S12.

The flash mode is a subroutine operation of steps S20 to S34 shown in FIG. In the flash mode, the control circuit 23 first checks in step S20 whether a specific mode and conditions such as macro mode and close-up shooting are performed. If the specific mode, the process proceeds to step S22.
Proceed to 21.

The control circuit 23, in step S22, the process proceeds to step S23 to set the charge stop voltage data V ₁ of the strobe. On the other hand, in step S21 it is not the specific mode, set the charge complete voltage data V ₀ which upon high general radiography than V ₁ proceeds to step S23. Incidentally, V ₀ is the charging voltage of the main capacitor 22 in the case of so-called fully charged, has a lower voltage value (V _0> V ₁₎ than V ₁ is V _0.

In step S23, the control circuit 23 supplies a high-level signal to the connection terminal b to make the switch element 14 conductive, and applies the charging voltage of the main capacitor 22 divided by the resistors 13 and 16 to the connection terminal c. And input via
This charging voltage is checked with an A / D converter. And
In step S24, the control circuit 23 makes a comparison between the voltage Vreg data set by the charging voltage and the step S21 or the step S22 (charge completion voltage data V ₀ or charge stop voltage data V _1). This step S2
In 4, the control circuit 23 performs a comparison between the charging voltage if a particular mode and charge stop voltage data V _1, and compares the charge voltage if the specific mode and the charging completion voltage data V _0. If the charging voltage is lower than the voltage of the Vreg data, the process proceeds to step S25 to prepare for charging,
If the charging voltage is higher than the voltage of the Vreg data, the process proceeds to step S30 to discharge the electric charge of the main capacitor 22.

The control circuit 23 supplies a high-level signal to the connection terminal d in step S30 to discharge the electric charge of the main capacitor 22 via the switch element 18 and the discharge resistor 17. Then, in the subsequent step S31, the main capacitor 22
It is determined whether or not the voltage of the main capacitor 22 becomes the same as the voltage of the Vreg data. The discharge of step S30 is continued until the voltage of the main capacitor 22 becomes the same as the voltage of the Vreg data. At the same time, a low-level signal is applied to the connection terminal d to stop the discharge, and the flash routine ends, and step S in FIG.
Move to 11.

On the other hand, the control circuit 23 determines that the charging voltage is Vreg
When the voltage is lower than the data voltage, the following control is performed. First, in step S25, the control circuit 23 activates a charge prohibition timer (hereinafter referred to as a charge prohibition timer) which is a timer for stopping charging of the main capacitor 22. In addition, in the prohibition timer, the main capacitor 22
Is set to a time sufficient for the voltage of V.sub.reg to reach the voltage of Vreg data.

In the next step S26, the control circuit 23
The charging of the main capacitor 22 is started. Specifically, the control circuit 23 outputs a high-level signal from the connection terminal a. As a result, a high-level signal is applied to the resistor 6, and a high-level signal is also applied to the control electrode of the switch element 7, and the resistor 6 is turned on. When the switch element 7 is turned on, the current from the battery 1
Flows through the switching element 7, the feedback winding (F) of the oscillation transformer 9 and the resistor 10, and becomes the base current of the oscillation transistor 5. When the base current of the oscillating transistor 5 flows, a collector current of _hFE times the current between the emitter and the base flows through the collector of the oscillating transistor 5, and this collector current is equal to the primary winding (P) of the oscillating transformer 9 to the battery. 1 to form a current loop between the emitter and the collector of the oscillation transistor 5.

Due to this current loop, an induced electromotive force is generated in the secondary winding (S) of the oscillation transformer 9, and the rectifier diode 12, the main capacitor 22, the battery 1, the emitter-base of the oscillation transistor 5, the switching element. The current flows in the loop of No. 7, and a current loop of the base current of the oscillation transistor 5 is formed, so that the oscillation transistor 5 is saturated.
When the collector current of the oscillating transistor 5 flows and the magnetic flux of the core of the oscillating transformer 9 saturates, a reverse starting force is generated in the oscillating transformer 9 and a high-voltage pulse is applied to the secondary winding (S) of the oscillating transformer 9. Voltage is generated. Capacitor 1
1 is connected to suppress the spike voltage peak due to the high-voltage pulse voltage.

The current caused by the high-voltage pulse flows through the switching element 7, between the base and emitter of the oscillation transistor 5, the battery 1, the main capacitor 22, and the parasitic capacitance of the rectifier diode 12. Then, since this current reversely biases between the base and the emitter of the oscillation transistor 5, the oscillation transistor 5 suddenly becomes non-conductive. When the saturation of the magnetic flux of the core of the oscillating transformer 9 is released, the oscillating transistor 5 becomes conductive again by the same operation as described above, and further repeats non-conduction and conduction / non-conduction, thereby oscillating. Thus, the main capacitor 22 is charged by the secondary current of the oscillation transformer 9 and the main capacitor 22 is charged.
The voltage of 2 rises.

The control circuit 23 outputs a high-level signal from the connection terminal b from immediately before charging to immediately after charging. When this high-level signal is output, the switch element 14 becomes conductive because its control electrode is at a high level. Then, the resistor 15 pulls down the control electrode of the switch element 14 at this time. When the switch element 14 conducts, the connection terminal c is connected to the resistor 13 and the resistor 1.
6 and a divided voltage is generated.

At this time, the potential V generated at the connection terminal c is as follows: V = (R16 / (R13 + R16 + RON)). ECEC: The charging voltage of the main capacitor 22 R13: The resistance value of the resistor 13 R16: The resistance value of the resistor 16 RON: It is given by the resistance value when the switch element 14 is on (conducting).

In this embodiment, when the charging voltage of the main capacitor 22 at the time of completion of charging is, for example, 330 volts, the value of the potential V generated at the connection terminal c is set to be about 2 volts. is there. Specifically, n-chFE
If an element having a gate drive voltage of 2 to 3 V is selected for the switch element 14 indicated by T, it is possible to control a high-level signal input via the connection terminal b to about 5 V.

The main capacitor 22 is charged by the secondary current of the oscillation transformer 9, and as the voltage of the main capacitor 22 increases, the potential generated at the connection terminal c also increases. When the charging of the main capacitor 22 is started in step S26, the control circuit 23 proceeds to the next step S26.
At 27, the potential generated at the connection terminal c is detected, and it is determined whether or not the charging is completed based on the potential. Specifically, the control circuit 23 determines that the potential generated at the connection terminal c has reached a predetermined level corresponding to the charge completion voltage V ₀ or the charge stop voltage V ₁ predetermined by the A / D converter of the control circuit 23. It is determined whether or not the charging has been completed. If the predetermined level has been reached, YES, that is, the charging has been completed, the process proceeds to step S28. If the predetermined level has not been reached, NO, that is, the charging has not been completed. Then, the process proceeds to step S32.

In step S28, the control circuit 23 stops outputting the high-level signal at the connection terminal a, and controls the main capacitor 22 to stop charging. That is, when the high level signal at the connection terminal a is cut off and becomes low level (open), the switch element 7 is turned off, and the oscillation transistor 5 is also cut off because the loop through which the base current flows is cut off, that is, oscillation stops. Therefore, charging of the main capacitor 22 is completed. In this case, the control circuit 23 sets a charge OK flag indicating that the charging is completed in the following step S29, and then proceeds to step S11 in the flowchart of FIG.

On the other hand, if the control circuit 23 determines in step S27 that the potential generated at the connection terminal c has not reached the predetermined level and that charging has not been completed, step S32 is performed.
It is determined whether or not the charging / receiving timer has counted up, that is, whether or not the charging / receiving timer has reached the end count value. If YES, that is, if it is determined that the end count value has been reached, it is determined that there is an abnormality. S3
The process proceeds to 3, and if it is determined that the count value has not reached the end count value, it is determined that there is no abnormality, and the process returns to step S27 to continue charging the main capacitor 22.

If the control circuit 23 determines that the charging / prohibiting timer has reached the end count value before charging is completed, the process proceeds to step S
At 33, the high-level signal provided via the terminal a is stopped to turn off the switch element 7, and the charging of the main capacitor 22 of the strobe device is stopped. At the next step S34, charging indicating incomplete charging is performed. The NG flag is set, and then the process proceeds to step S11 in the flowchart of FIG.

Here, description will be made again with reference to the flowchart of FIG. The control circuit 23 determines whether or not the charging of the main capacitor 22 has been completed by detecting the type of the above-described flag in step S11,
When it is determined that the charging is completed, the process proceeds to step S12, and when it is determined that the charging is not completed, the process returns to step S2 and the above-described steps S2 to S11 are performed.
Is repeated.

If it is determined in step S9 that the subject brightness is higher than the predetermined value, or if it is determined in step S11 that the charging of the main capacitor 22 has been completed, in step S12, the control circuit 23 sets the second release button It is determined whether or not the stroke switch SW2 is ON and ON.
If it is OFF, the process proceeds to step S13. If it is OFF, the process returns to step S2 and the above-described steps S2 to S1
The processing up to 2 is repeated. And the switch SW2 is set to O
If N, in step S13, the control circuit 23 controls the lens driving circuit 36 based on the distance measurement data measured in step S7 to adjust the focus.

In the next step S14, the control circuit 23
The shutter opening speed is adjusted by controlling the shutter circuit 38 under the conditions based on the luminance of the subject obtained by the photometry in step S8 and the ISO sensitivity data input from the film sensitivity detection circuit 32, and then in step S15. Proceed to. Also, in step S14, step S
If it is determined in step 9 that the luminance is low and light emission (hereinafter referred to as flash) of the flash discharge tube 21 in the strobe device is required, shutter control is performed based on distance measurement data and ISO sensitivity data, and a predetermined aperture value is set. The flash discharge tube 21 emits light.

The flash tube 21 emits light by applying a high level signal to the terminal e in FIG. 1 and applying a high pulse voltage to the trigger electrode of the flash tube 21.
That is, in this camera with a built-in strobe, when a high-voltage pulse voltage is applied to the trigger electrode of the flash discharge tube 21, the flash discharge tube 21 is excited, the impedance is reduced, and the main capacitor 22 is discharged at a stretch. This discharge energy is converted into light energy by the flash discharge tube 21 and illuminates the subject as auxiliary light.

At this time, in the case of shooting in a specific mode such as macro shooting or close-up shooting, the main capacitor 22 is charged only to a predetermined charging voltage lower than that at the time of full charge in general shooting. Also, the light energy emitted from the flash discharge tube 21 becomes weak due to the discharge of the main capacitor 22, and accordingly, it is possible to avoid a small aperture by opening the aperture by a predetermined number of steps. It is possible to perform appropriate photography while suppressing occurrence.

When the flash is used, the control circuit 23 sets 1 as a flash flag FAL indicating that the flash has been used, and proceeds to step S15.

Step S1 after the shutter is opened
In step 5, the control circuit 23 controls the lens driving circuit 36 to return the lens at the focal position to the initial standby position, and in the next step S16, drives the film so as to wind up the photographed film by one frame. The circuit 37 is controlled. In the next step S17, the control circuit 23 determines whether or not “1” is set in the flag FAL indicating that the flash has been used. If YES, that is, if the flag FAL is set to 1, the process proceeds to step S18. If NO, that is, if 1 is not set in the flag FAL, the process returns to step S2 of switch detection and repeats the above steps S2 to S18.

The control circuit 23 shifts to the flash mode in step S18 when it is determined that the flag FAL is set to "1". In this flash mode,
Similar to the flash mode in step S10, the main capacitor 22 is charged according to the subroutine in FIG. On the other hand, when the flash is not used, the process returns to the sequence of step S2 without passing from step S17 to step S18 as described above, and a series of photographing sequences is repeated.

As described above, in the camera with a built-in strobe, the main capacitor 22 is charged at a predetermined charging voltage lower than that at the time of full charge at the time of general shooting when shooting in a specific mode such as macro shooting or close-up shooting. To stop,
Irradiation light from the flash discharge tube 21 due to the discharge of the main capacitor 22 becomes weak, and accordingly, it is possible to avoid a small aperture by opening the aperture by a predetermined number of steps. It becomes possible to take a photographic image.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and in FIG.
Only the circuit on the side of the strobe device is shown, and the respective circuits on the camera side such as the control circuit 23 are the same and are not shown.

In the second embodiment, a diode 24 is connected between the control electrode of the switch element 7 and the control electrode of the switch element 14 as shown in FIG.
A diode 25 is connected between the control electrode of the switch element 18 and the control electrode of the switch element 18. The diode 24 has a cathode connected to the control electrode of the switch element 14 and an anode connected to the control electrode of the switch element 7. On the other hand, the diode 25 has a cathode as a control electrode of the switch element 14,
The anodes are connected to the control electrodes of the switch element 18, respectively. In this embodiment, the diode 24
Is the connection terminal a in the control circuit 23 of the camera.
The diode 25 is connected to the connection terminal d in the control circuit 23.
Are connected to each other.

With such a configuration, in a camera with a built-in strobe, the connection terminal b of the control circuit 23
Becomes unnecessary, and the number of connection terminals of the control circuit 23 and the associated control processing can be reduced.

In this embodiment, when the control circuit 23 outputs a high-level signal from the connection terminal a, the charging operation of the main capacitor 22 in the strobe device and the detection of the charging voltage are performed at the same time. By outputting the high level signal, the discharge operation of the main capacitor 22 and the detection of the discharge voltage are performed simultaneously, and as a result,
The connection terminal b and the output of the signal from the connection terminal b are not required. Further, the resistor 6 and the resistor 19 shown in FIG. 4 can be eliminated by also using the resistor 15.

In the above-described camera with a built-in strobe, in order to make the emission voltage of the flash discharge tube 21 from a low voltage, it is possible to use a known doubler circuit to increase the variation width of the light amount. is there. Here, the main capacitor 22
Assuming that the full charge voltage is about 320 V, the minimum light emission voltage is about 250 V in the general trigger method, and the minimum light emission voltage is about 160 V in the double pressure trigger method for about -0.7 steps in terms of the number of stages. Similarly, if the number of stages is indicated, it is possible to open the aperture by about -2 stages.

If the charging capacity is sufficient, the resistance 1
It is also possible to reduce the voltage dividing resistance of the voltage detection circuit constituted by 3, 5, 16 and the switch element 14, and to use this voltage detection circuit also as a discharge circuit. Can be omitted.

[0057] Although described in one charge stop voltages V ₁ lower than the full charge voltage V ₀ which the main capacitor 22 in each embodiment described above, the present invention is not limited thereto, for example, step S7 A plurality of charge stop voltages V1 may be set based on the distance measurement information (AF data) from the distance measurement circuit 35 measured in step ( ₁ ). In this case, it is should be high enough to charge stop voltages V ₁ the distance to the subject is far based on AF data.

In the above-described embodiment, an example is shown in which the present invention is applied to a camera with a built-in strobe in which an electronic flash device and a camera are integrated. However, the present invention is not limited to this. Of course, it is also applicable.

[0059]

As described in detail above, according to the present invention, the charging voltage value of the main capacitor can be switched to either the full charging voltage value or the charging stop voltage value in accordance with the photographing conditions. Since the charge amount of the main capacitor supplied to the flash discharge tube can be switched, for example, when shooting under specific conditions such as macro or close-up shooting, the charging of the main capacitor is stopped lower than when fully charged during general shooting It is possible to stop charging at the voltage value. As a result, the irradiation light from the flash discharge tube becomes weak, and accordingly, it is possible to avoid a small aperture by opening the aperture by a predetermined number of steps. It is possible to do. That is, it is possible to take a proper photograph with a simple configuration without using a large-sized and expensive component such as a thyristor or an IGBT.

Therefore, according to the present invention, there is provided a strobe device which contributes to downsizing and cost reduction, suppresses the occurrence of variation in aperture accuracy, and enables appropriate photographing, and a camera provided with this strobe device. It is possible to do.

[Brief description of the drawings]

FIG. 1 is a diagram for describing a first embodiment of the present invention, and is a circuit configuration diagram illustrating a main portion of a camera with a built-in strobe extracted.

FIG. 2 is a flowchart illustrating an operation of a camera with a built-in strobe.

FIG. 3 is a flowchart showing a charging operation of a main capacitor in a specific mode of the camera with a built-in flash.

FIG. 4 is a circuit diagram showing a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Battery 5 ... Oscillation transistor 9 ... Oscillation transformer 7, 14, 18 ... Switch element 13, 16 ... Divider resistance 17 ... Discharge resistance 20 ... Light emitting circuit 21 ... .. Flash discharge tube 22 ... Main capacitor 23 ... Control circuit 24, 25 ... Diode 30 ... Constant voltage circuit 31 ... Switch circuit 32 ... Film sensitivity detection circuit 33 ... Display Circuit 34 Photometric circuit 35 Distance measuring circuit 36 Lens driving circuit 37 Film driving circuit 38 Shutter circuit

Claims (9)

[Claims] A light emitting means having a flash discharge tube; a main capacitor for supplying electric charge to the flash discharge tube; a boosting means for boosting a power supply voltage to charge the main capacitor to a high voltage; Detecting means for detecting the potential of the electric charge charged in the capacitor; discharging means for discharging the charged electric charge of the main capacitor; and controlling the operation of the boosting means and the discharging means based on the detection value of the detecting means. Control means for controlling the light emitting means so as to supply the electric charge charged in the main capacitor to the flash discharge tube, wherein the control means includes a full charge voltage value as a charge voltage value of the main capacitor. At least one or more charge stop voltage values lower than the full charge voltage value, and the boosting means and the boosting means such that the detection value of the detection means becomes a value corresponding to the photographing condition. An electronic flash device that switches a charging voltage value of the main capacitor to one of the full charging voltage value and the charging stop voltage value by outputting a control signal to a discharging unit. 2. The control unit according to claim 1, wherein when performing photographing under specific conditions, the control unit controls the boosting unit and the discharging unit so that a detection value of the detection unit becomes a value corresponding to the charge stop voltage value. The electronic flash device according to claim 1, wherein the electronic flash device is controlled. 3. The control unit, when performing photographing in a macro mode, controls the boosting unit and the discharging unit so that a detection value of the detecting unit becomes a value corresponding to the charge stop voltage value. The electronic flash device according to claim 1, wherein the electronic flash device is controlled. 4. The control unit according to claim 1, wherein, when performing photographing at a short distance, the boosting unit and the discharging unit adjust the detection value of the detection unit to a value corresponding to the charge stop voltage value. The electronic flash device according to claim 1, wherein the electronic flash device is controlled. 5. The boosting means and the detecting means, and the discharging means and the detecting means are respectively connected via rectifying elements, and a control signal is sent from the control means to the boosting means or the discharging means. 5. The electronic flash device according to claim 1, wherein said detection means is activated simultaneously with the input. 6. The detecting means includes a voltage dividing resistor circuit connected to the main capacitor, and an A / D converter for A / D converting a divided voltage value detected by the voltage dividing resistor circuit, The electronic flash device according to claim 1, wherein the control unit performs digital processing based on an output from the A / D converter detection unit. 7. A camera comprising the electronic flash device according to claim 1. 8. A distance measuring means for detecting a distance to a subject, wherein said control means controls the detection value of said detecting means based on a detection value of said distance measuring means to a value corresponding to a photographing condition. 8. The camera according to claim 7, wherein the camera controls the booster and the discharger. 9. The control unit controls the boosting unit and the discharging unit based on a detection value of the distance measuring unit such that the charging voltage value of the main capacitor increases as the distance to the subject increases. The camera according to claim 8, wherein