JP3122446B2 - Strobe control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strobe control device for controlling charging of a strobe of a camera, and more particularly to a device capable of detecting a charging voltage at a small level and using the detected voltage. Things.

[Problems to be Solved by Related Art and Invention] A conventional strobe circuit is used to determine whether or not a charged voltage of a main capacitor has reached a predetermined detection level and to perform light emission permission or display. I have.

When the above detection level is one step, fine control according to the charging voltage is impossible.

On the other hand, when the detection level is multi-stage, a configuration is adopted in which the charging voltage is divided and A / D converted, and whether or not each level has been reached is individually determined. Not only is this disadvantageous in terms of space, but also the cost is increased due to the complexity of the circuit.

[Object of the Invention] The present invention has been made in view of the above problems, and has as its object to provide a strobe control device capable of detecting a charging voltage in multiple stages with a simple configuration.

Means for Solving the Problems The present invention has been made to achieve the above object, and a first aspect of the present invention relates to a case where a voltage check signal for checking a charging voltage of a main capacitor for a strobe is input. A pulse output unit that outputs a pulse having a time width according to the charging voltage of the main capacitor, and a voltage measuring unit that detects the charging voltage by measuring the time width of the pulse, wherein the pulse output unit includes: The switch outputs a pulse only when the charging voltage exceeds a predetermined reference voltage, and switches ON / OFF based on a voltage check signal for checking the charging voltage of the main capacitor. However, it has the characteristic of turning off when the energizing current falls below the energizing holding current, and the hysteresis in which the voltage of the main capacitor is applied by turning on the switch means. An element, and the switch means is turned on while the hysteresis element is energized.
And a compensating means for compensating the energization of the hysteresis element until the energization current to the hysteresis element is reduced to the energization holding current after turning off from the ON state, wherein the compensation means compensates for the energization of the hysteresis element. Wherein the reference voltage is a strobe light emission permission voltage.

According to a second aspect, the hysteresis element according to the first aspect is a neon tube.

A third aspect is characterized in that the compensation means according to the first aspect is a capacitor.

[Example] Hereinafter, the present invention will be described with reference to the drawings.

1 to 27 show an embodiment of the present invention.

First, the appearance of a camera equipped with a flash control device according to this embodiment will be described with reference to FIGS.

In FIG. 1, reference numeral 1 denotes a camera body, and reference numerals 2 and 3 denote zoom lens barrels. A distance measuring unit 4, a finder window 5, a strobe 6, a CdS as a photometric light receiving element, and a self-timer lamp 7 are provided on the front side of the camera body 1 as shown in FIG. On the side, a back cover 8, an LCD display 9, a mode button A, a mode button B, a clear button C, a zoom lever 10, a green lamp D, a red lamp E, and a back cover release lever 11 are provided. Is operated in the direction of the arrow from the ascending stop position to the descending stop position, the back cover 8 is opened. When the back cover 8 is open, the back cover opening lever 11 is at the lower stop position,
When the back cover 8 is closed, the back cover opening lever 11 is raised.

The back cover 8 has a date display section 12 and a date switch button.
13 are provided. A rewind button (not shown) is provided on the bottom of the camera body 1.

As shown in FIG. 1, a power lever 14, a shutter button 15, and a macro button 16 are provided on the upper part of the camera body 1. The power lever 14 is slid between a power ON position and a power OFF position.

The zoom lever 10 has an arrow r1 between the wide side and the tele side,
Operated in r2 direction.

By operating the power lever 14 and the macro button 16, the zoom lens barrels 2 and 3 can be moved from the locked position in the retracted state to the zoom range between the wide end (focal length 35 mm) and the tele end (focal length 70 mm), The zoom lens is moved between a macro position for close-up shooting and a zoom operation of the zoom lever 10 in the zoom range.

FIG. 4 shows a circuit configuration of the camera described above.

The main CPU of this control circuit is a main CPU, and a sub CPU that performs shutter-related processing in parallel with the main CPU is connected via a drive IC.

The main CPU performs the following control based on an input from information input means such as a switch.

(1) The zoom motor and the film motor are controlled via each motor drive circuit.

(2) The lighting and blinking of a green lamp D for displaying distance measurement, a red lamp E for displaying strobe light, and a self-timer lamp 7 for displaying self-timer are controlled.

(3) The display of the LCD display position 9 is controlled.

(4) Control charging of the strobe circuit.

And as information input means to the main CPU,
There are the following:

(1) Lock switch LOCK that turns ON when the power lever 14 is turned to the power OFF position.

(2) A photometric switch SWS that is turned on by pressing the shutter button 15 one step.

(3) A release switch SWR that is turned on by pressing the shutter button 15 twice.

(4) A self-back macro switch MCRO that turns ON when the macro button 16 is pressed.

(5) Turn on by moving the zoom lever 10 to the tele side r2.
Tele switch tele to zoom.

(6) By moving the zoom lever 10 to the wide side r1
Wide switch WIDE for zoom to turn on.

(7) A self-back mode A switch MDA, mode B switch MDB, and clear switch MDC that are turned on by pressing the mode buttons A and B and the clear button C.

(8) When the back cover release lever 11 is pushed down, it turns off and the back cover 8
The back cover switch BACK that turns ON when the lever is raised to the locked position after closing.

(9) A self-back rewind switch REW that is turned on by pressing the rewind button.

On the other hand, the sub CPU uses the infrared L
Controls the distance measurement unit consisting of ED and PSD, and also measures distance measurement data based on the output of this autofocus IC and Cd
The photometric data based on the output of S is transferred to the main CPU.

The drive IC controls the shutter circuit and outputs a trigger signal TRG of the strobe circuit based on a command from the sub CPU.

Details of the strobe circuit are as shown in FIG. In FIG. 5, the main CPU and the sub CPU are collectively displayed.

This circuit is based on a battery
A regulator that stabilizes the supply voltage to the CPU irrespective of the voltage change of T, a booster circuit that boosts the battery voltage by the charge enable signal CHEN from the CPU and starts charging the main capacitor C1, and a trigger signal from the CPU Trigger circuit that makes Xe (xenon) tube emit light by TRG, and voltage check signal CHCK from CPU to RLS charge voltage of main capacitor
And a voltage detection circuit for detecting as a pulse.

The boost circuit consists of a boost transformer and an oscillation transistor
Tr1, Tr2, resistors R1, R2, R3, capacitor C2, diode D1,
D2, the charging is started when the charging permission signal CHEN becomes L (low level output), and stopped when the charging permission signal CHEN becomes H (open).

The voltage detection circuit includes a Ne (neon) tube for determining a reference voltage, a switching transistor Tr3, a transistor Tr4 for generating an RLS pulse, resistors R4 to R8, and a capacitor C3. Changes from H (high-level output) to L (low-level output) to generate an RLS pulse proportional to the voltage. The Ne tube shown here starts lighting by applying a voltage of 270 V or more, and maintains a voltage near 220 V regardless of the current value during lighting. The hysteresis between the lighting start voltage and the lighting holding voltage is used for generating an RLS pulse.

Here, the principle of voltage detection will be described with reference to FIG.

When the voltage check signal CHCK is set to H, the transistor
At the same time that Tr3 is turned on and capacitor C3 is discharged, N3
The negative side of the e-tube is connected to the ground via a resistor R4 and a transistor Tr3. At this time, if the charging voltage VF is 270 V or more, the Ne tube is turned on after the elapse of the lighting delay time from H of CHCK, and the current flows in the order of the Ne tube, R4, and Tr3.
Therefore, the voltage on the Ne tube side of the resistor R4 becomes a value VF−VN obtained by subtracting the lighting holding voltage VN of the Ne tube from the charging voltage VF.

Next, the voltage check signal is set to L and the transistor Tr3
Is turned off, the current flowing from the resistor R4 to the transistor Tr3 flows from the resistor R4 to the capacitor C3 for a while. As a result, the capacitor C3 is charged, the transistor Tr4 is turned on, and RLS becomes L.

As the charging of the capacitor C3 proceeds, the capacitor C3 of the resistor R4
The potential on the side gradually increases, and the current necessary to maintain the lighting of the Ne tube cannot flow. This turns off the Ne tube,
Since the current from the resistor R4 to the capacitor C3 also stops flowing,
The transistor Tr4 is turned off and RLS becomes H.

Since the turn-off timing of the Ne tube is delayed as the charging voltage VF is higher, the time (RLS pulse width) T during which RLS is L is determined by (VF-VN).

Therefore, the charging voltage VF can be detected by detecting the pulse width T.

FIG. 7 shows an example of the relationship between the charging voltage and the RLS pulse width.

When the charging voltage is 270 V or less, the Ne tube is not turned on even if the transistor Tr3 is turned on, so that the RLS remains at H.

Next, the functions of the mode buttons A and B will be described.

The mode button A has a function of setting an exposure method,
Six types of exposure methods are prepared: auto (auto flash mode), flash ON (flash forced mode), flash OFF (flash disabled mode), exposure compensation, bulb, and bulb & flash ON.

When the exposure method is valve or valve & strobe ON,
Eight types of manual shutter time are prepared.

The mode button B has a function of setting a shooting method,
Here, the shooting methods include single-frame shooting, continuous shooting,
Six types are prepared: self-timer, double self, multiple shooting, and interval.

Sixteen types of interval times are prepared for the intervals of the shooting method.

Note that the initial value of the manual shutter time is the valve, the initial value of the interval time is 60 seconds, and the execution of the mode initialization process or the ON of the clear button C is performed.
Is set by

Next, the program stored in the above-described main CPU will be described along with the operation of the camera in accordance with the flowcharts shown in FIGS.

<< Main Processing >> First, the reset processing and the main processing shown in FIGS. 8 to 13 will be described. The main processing defines the basic operation of the camera, and the other processing is performed by branching or calling from the main processing according to various conditions.

When the power is turned on, the reset of the main CPU is released, and the reset processing of FIG. 8 is started. The main CPU initializes the memory and inputs switch data in steps (hereinafter referred to as S.) RS1 and RS2.
In 3, a mode initialization process is performed, a zoom initialization process is performed in S.RS, and then a main process is started. In the mode initialization process, the settings of the various modes described above are returned to the initial values, and the automatic flash light emission,
This is a process for setting a frame shooting mode.

In the main processing, a one-second timer used for display hold in S.MI1 is cleared and started.

For S.MI2 to MI4, switches are set when all of the photometric switch SWS, release switch SWR, wide switch WIDE, tele switch TELE, mode A switch MDA, mode B switch MDB, clear switch MDC, and macro switch MCRO are OFF. 1 is set to the judgment flag? SWOFF, and any
If it is ON, 0 is set. In the following description, the flag name is prefixed with “?” To distinguish it from other symbols.

In S.MI5 to MI8, all four switches, photometry switch SWS, release switch SWR, wide switch WIDE, and tele switch TELE, are OFF, and a combination of modes in which shooting is prohibited in the mode setting is not selected. In this case, 1 is set to the photometry switch valid flag? SWSEN, and 0 is set when any of the switches is ON or when a mode combination for inhibiting photography is set.

The state of each switch described above is input to S.MI9, and processing is performed based on the input switch data.

First, if it is determined in S.MI10 that the rewind switch REW is ON, the mode is initialized in S.MI11, and then the loop exit processing shown in FIG. 10 is performed in S.MI12. This process consists of two steps: a strobe circuit charge stop process S.LO1 described later and a charge display red lamp S.LO2, which is always called before branching from the main process to another process. You.

After the loop exit processing, the flow branches to the S.MI 121 rewind processing. The rewind process is not described in detail,
When the rewinding of the film is completed, the rewind end flag
? REWEND is set to 1 and the processing jumps to the beginning of the main processing and proceeds.

When the back cover is closed and the back cover switch BACK is ON, it is determined in S.MI14 whether or not the loading is completed from the state of the loading end flag? LDEND. If the loading is not completed (? LDEND) = 0), the process branches to the S.MI161 loading process via the mode initialization process of S.MI15 and S.MI16 and the loop exit process. If the processing has been completed, S.MI17 and MI18 are skipped and the processing proceeds.

When the loading process is completed,? LDEND is set to 1, and the process jumps to the head of the main process and proceeds.

If the back cover is open, in S.MI17, MI18?
LDEND.?REWEND is cleared.

In S.MI19 to MI24 in FIG. 11, the lock switch LOCK is
It shows the processing when the power is turned on from F, that is, when the power lever is moved from the power on position to the power off position.
If it is determined that the taking lens is not in the locked position,
After switching the display of the number of films on the LCD display to the focal length display, the exit process is performed, and the process branches to the zoom reversal process to return the lens to the lock position. If the lens is already at the lock position and the rewind has not been completed, the process branches to a lock process described below via a loop exit process. If the rewind has ended, the processing jumps to the position of “MID” in the main processing shown in FIG. 13 and the processing proceeds.

If the lock switch LOCK is OFF and the lens is determined to be in the lock position in S.MI25,
In S.MI26 and MI27, the focal length is displayed, and the display hold flag? WAITD is set to 1 so that the display is held for 1 second. This hold processing will be described at the end of the main processing. Then, macro request flag in S.MI28
? RQMCRO is set to 0, the exit process is executed in S.MI29, and the process branches to the normal zoom process. In the normal zoom process, if the macro request flag? RQMCRO is 0, the lens is moved from the lock position to the wide end, and if the flag is 1, the lens is moved to the macro position.

In S.MI30 to MI36, when the macro switch MCRO is ON, the focal length is displayed and the display hold flag? WAITD is set to 1. Then, it is determined whether or not the photographing lens is at the macro position, and if it is at the macro position, the display hold timer is cleared and started, and the process jumps to “MIC” in FIG. 13 to proceed. If the macro position is not at the macro position, the macro request flag? RQMCRO is set to 1, the process exits the loop, branches to the normal zoom process, and moves the lens to the macro position.

Subsequently, in S.MI37 to MI43 shown in FIG. 12, when the tele switch TELE is ON, the display is switched to the focal length display and the display hold flag is set. Is in the macro position or in the zoom range. If the lens is in the zoom range, the process branches to the tele-movement process to move the lens to the telephoto side.

If the lens is already at the telephoto end, the display timer is cleared and one second is counted again from this point.

In S.MI44 to MI50, when the wide switch WIDE is ON, the display is switched to the focal length display and the display hold flag is raised.
At 48, the timer is cleared and started, and the main processing proceeds. If the lens is not at the wide end, it is determined through a loop exit process whether the lens is in the macro position or in the zoom range.

If the lens is in the zoom range, the process branches to a wide moving process to move the lens to the wide side. If the lens is at the macro position, the process branches to the zoom reverse rotation process and the lens is returned to the telephoto end.

Therefore, the setting of the photographing lens to the macro position is performed by turning on the macro switch, and in order to return the lens set to the macro position to the zoom range, the zoom lever may be operated in either direction.

In S.MI51 to MI54 in FIG. 12, the macro teleshift flag
? When it is determined that a shift is requested from the state of MTSIFT, the focal length display process is performed, the display hold flag? WAITD is set to 1, the process exits from the loop, branches to the zoom reverse process, and the lens is telephoto. Pull back to the end.

Since the long distance limit of macro shooting is about 1 meter,
If the lens is in the macro position and the distance measurement result is 1 meter or more, a photograph in focus cannot be obtained even if the shutter is released. Therefore, in this camera, the release lock is applied in such a case, and the camera is controlled to shift from the macro position to the telephoto end. The flag? MTSIFT is set in the LL arithmetic processing in the AEAF control processing.

Subsequently, in S.MI55, the state of the rewind end flag? REWEND is determined, and if the rewind has ended, the S.MI55
In step 56, display “00EX” on the LCD. If this flag is 0, the mode setting process is called in S.MI57.

In the mode setting process, the switch judgment flag? SWOFF set in S.MI2 to MI4
Only when the switch is turned off, the setting process is started. When any switch is turned on, the process returns to the main process without performing the setting.

If the mode is changed during this mode setting processing, the mode change flag? MDCHG is set to 1; otherwise, it is set to 0.

When returning from the mode setting process, the state of the flag set in S.MI58 is determined, and if the mode is changed, the display hold flag is set to 1 in S.MI59 and MI60, and the process exits from the loop. Jump to the beginning of the main processing.

If the mode has not been changed, the photometry switch SWS and the photometry switch valid flag? SWSEN
Is determined, and when a predetermined condition is satisfied, S.MI63 ~
The focal length is displayed by the MI65, the display hold flag is cleared, and the process branches out to the AEAF control process for performing shutter-related control through the loop exit process.

The process branches to the AEAF control process when the photometry switch is ON, the SWS, SWR, TELE, and WIDE switch data stored in the memory are all OFF, and the shooting mode is set. It is. That is, the process branches to the AEAF control process only when the SWS changes from OFF to ON,
When the zoom lever is operated, the main processing is continued without branching.

In S.MI66, a charge control process described below is called, and S.MI
The display switching process is executed in 67 to MI71.

When the display hold is requested, it is determined whether or not one second has passed since the clearing of the display timer.

Before the timer expires for one second, the currently displayed display is held.

If the display hold is not requested, or if the timer has elapsed for 1 second, if the display other than the number display is displayed, the number is displayed and the display hold flag? WAI
Clear TD.

As described above, the display of the number of films is preferentially displayed over other displays except when the display is temporarily switched.

Then, after stopping the 125 ms process in S.MI72, a charge prohibition time process described later is called in S.MI73, and after returning, jumps to S.MI12 of the main process to continue the process.

This camera delays the start of charging by a charging prohibition time set according to the frequency of use of the strobe in order to prevent heating of the strobe circuit due to continuous use of the strobe as described later. The charging prohibition time process is a process for shortening the charging prohibition time set when the strobe is not used.

This concludes the description of each step of the main processing. Subsequently, a flow and a subroutine branched from the main processing will be described.

<< Charge Control Process >> The charge control process called in the S.MI66 of the main process or the release standby charge process and the interval control process to be described later will be described with reference to FIG. This processing is the main processing of charging execution, and 125 ms from any processing.
Called periodically.

In S.CC1, it is determined whether or not the charging inhibition time provided for preventing the heating of the flash circuit has elapsed based on the inhibition time completion flag? FWTCMP. If the charging inhibition time has not elapsed (0), S.CC2 is determined. After executing the charging prohibition process described later in
In C3, it is determined from the state of the during-prohibition time flag? FWTSTR whether or not the prohibition time is in progress. If it is determined that the prohibition time is being set (1), the process branches to S.CC7 to execute a charge stop process.

Charge prohibition time completed and prohibition time completion flag? FWTCMP
Is set to 1, or when the charge inhibition time is completed during the charge inhibition processing and the inhibition time flag? FWTSTR is set to 0, the state of the charge request flag? CHGRQ is determined in S.CC5. If there is a charging request (1), the process proceeds to S.CC6, and if not, to S.CC4.

In the charging stop process, the S.CC4 sets the prohibited time reduction prohibition flag? FCNTSTP to 0 to allow the shortening of the charging prohibited time in the charging prohibited time process described later.
In C9, the charging and the voltage check are stopped, the red lamp is turned off, and the process returns to the called step.

When a charge request is made, a timeout flag? FTO set in the timeout check process described later in S.CC6
It is determined whether or not 8 seconds or more have elapsed from the start of charging based on the state of the UT. If the time has elapsed (1), the charging flag? FCHG, the prohibited time completion flag? FWTCMP, and the charging request in S.CC10 After clearing the flag? CHGRQ, stop charging.

If 8 seconds have not elapsed, before charging starts (? FCHG
= 0), charging flag? FCH in S.CC11 to CC15
The charge time timer is started with G set to 1, and a voltage check signal is output while charging is prohibited. This is because the charging voltage at the start of charging is unknown, so that the voltage is measured before charging is performed.

If charging is in progress, branch from S.CC11 to S.CC1
6, RLS pulse time measurement processing and timeout check processing, which will be described later, are executed in CC17, and it is determined whether or not charging has been completed based on the state of the charge completion flag? FCCMP set in both processings. This flag is set to 1 when the charging voltage becomes 330 V or more during the normal RLS pulse time measurement process. However, when the charging voltage does not reach 330 V even after 8 seconds from the start of charging, the flag is charged to 270 V or more. If so, it is set to 1.

If the charging is determined to be completed (? FCCMP = 1), a charging stop process is executed via S.CC10, and if it is determined to be incomplete, S.CC
At 19 to CC21, a charge permission signal and a voltage check signal are output, and the routine returns.

Therefore, at the start of charging, the processes of S.CC12 to CC15 are executed once and a charge check signal is output for measuring the charging voltage. Then, after 125 ms, the charging voltage is measured through the processing of S.CC16 to CC21. If the charging voltage has not reached 330 V, charging is started. The process of S.CC16 to CC21 is repeated during charging, and the process of S.CC7 to CC9 is executed at the end.

<< Charge Prohibition Process >> FIG. 15 shows a charge prohibition process called in S.CC2 of the charge control process.

This process is called when the charging prohibition time has not been completed, and compares the charging prohibition time TW with the prohibition time timer to cause the strobe charging to wait for the charging prohibition time for preventing the flash circuit from heating. Charge prohibition time TW
Is determined based on the inhibition time data n set in the RLS pulse time measurement processing and the charging inhibition time processing.

If it is determined in S.CS1 that the prohibition time timer has not started (? FWTSTR = 0), the prohibition time timer is started in S.CS2 and CS3, and the prohibition time flag and the prohibition time reduction prohibition flag are set. Is set to 1 so that the charging is stopped in the charging control process of FIG.

S. In CS4 to CS8, when the prohibition time data is larger than n50, the prohibition time is set to 10 seconds
Set 10-second setting flag? FWT10S to force data n to 50
If the value is larger than 7 and smaller than 50, this flag is cleared and the routine returns.

If the prohibition time data n is 7 or less, S.CS9 to C.C
In S11, the prohibition time processing is canceled and the routine returns.

If this processing is executed after the prohibition time processing is started, the processing proceeds from S.CS1 to S.CS12.

In S.CS12 to CS15, if the prohibition time 10 second setting flag is not set, the prohibition time TW is set to nx125ms, and the prohibition time timer started in S.CS2 exceeds the prohibition time TW. Judge whether or not it is prohibited
If the 10-second setting flag is set, it is determined whether or not the prohibition time timer has passed 10 seconds.

Before the prohibition time timer exceeds TW or 10 seconds, the process returns as it is, and when it exceeds, the prohibition time is completed in S.CS9 to CS11 and the process returns.

Therefore, the inhibition time is 0 ms when n <7, and 7 ≦ n <50.
In this case, it is n × 125 ms, and when n ≧ 50, it is 10 seconds. As will be described later, n is incremented by 2 for one charge, and decremented by 1 when released for 4 seconds, so that the charge inhibition time according to the frequency of use of the strobe is always set.

<< RLS pulse time measurement processing >> Fig. 16 shows the RLS called by S.CC16 of the charge control processing.
It shows a pulse time measurement process. This process
This is a process of measuring the charging voltage of the main capacitor for the strobe based on the pulse time converted from the voltage-time.

2ms after setting the voltage check signal to L in S.RL1 ~ RL4
Before the timer expires, it is determined whether or not RLS becomes L.

As described above, RLS becomes L when the charging voltage is 270 V
As above, it is only when the Ne tube is lit, so 2 ms
If RLS remains H, the charging voltage is determined to be 270 V or less, the charging voltage 270 V and 280 V flags are both cleared in S.RL5 and RL6, and DGV is set to 0/4 before returning.

The strobe capacitor is fully charged at a voltage of 330 V, and the guide number is determined by the amount of light emitted at this time. On the other hand, in this camera, even if the capacitor is not fully charged, light may be emitted only for the charged amount. Therefore, a proper exposure cannot be obtained unless the guide number is corrected by the charging voltage. DGV is a parameter indicating the amount of correction of the guide number by the strobe charging voltage, 2/4 at 315 V or higher, 1/4 at 285 V to 315 V,
Set to 0/4 below 285V.

If RLS becomes L before the 2 ms timer expires, that is, if the charging voltage is 270 V or more, RLS is set to H by the RLS pulse time timer in S.RL7 to RL9.
Is measured and set to the pulse time T.

After the start of charging, the charging voltage exceeds 270 V, and the L level is low for the first time.
Appears and proceeds to S.RL10, S.RL11 to RL14
Is performed once, and the measurement reference time T1 is corrected based on the measured RLS pulse time T. If 500 ms has elapsed since the start of charging, the average value T1AV of the past T1 stored in the RAM
After determining T1 with emphasis on
Add 2 to the prohibition time data n as T1AV.

Before 500ms elapses from the start of the charge time timer, RLS
Becomes L, it is determined that the battery has been charged to 270 V or more from the beginning, and T1 is not corrected, and the value of T1AV is set to T1. In this case, it is determined that the charging time is short and the rise in the temperature of the transformer is small, and the prohibition time data n is not added.

The charging voltage VF and the RLS pulse time have a fixed relationship as a design value as shown in FIG. However, there is a possibility that some variation will occur for each product. Therefore,
The value of the first RLS pulse, which is considered to correspond to the charging voltage of approximately 270V, is averaged for each charging time and added to the evaluation of the pulse time to correct for differences due to product variations in voltage detection. .

In S.RL15 and RL16, the charging voltage 280V flag? FCH270 is cleared, the DGV is set to 0/4, and the charging voltage 270V flag? FCH270 is set to 1
And

In the second and subsequent RLS pulse time measurement processes after the charging voltage becomes 270 V or higher, the latest in S.RL17 to RL25
The charging voltage is determined by comparing the RLS pulse time T with the voltage corresponding time.

Voltage response time is 330V for T1 / 2 + 800μs, T1 / 2 + 700μ
s is 315V, T1 / 2 + 500μs is 285V, T1 / 2 + 400μs is 280V
It is designed to be. In FIG. 7 described above,
An example in which T1 is 600 μs is shown.

If the voltage is 330 V or more, the charge completion flag? FCCMP is set to 1. Then, a DGV corresponding to the voltage is set, and if the charging voltage is 280 V or more, the charging voltage flag is set to 1 and the process returns.

If it is 280V or less, the control returns via S.RL15 and RL26.

<< Time-out Check >> M FIG. 17 shows a time-out check process executed in S.CC17 of the charge control process. This process defines the upper limit of the charging time based on the measurement time of the charging time timer started in S.CC12 of the charging control process.

This processing is composed of steps S.TO1 to TO9. If charging is continued even after the charging time timer has elapsed for 6 seconds, the time-up flag? FCHTUP is set to 1.

If 8 seconds have elapsed, the charging completion flag? FCCMP is set to 1 if the charging voltage has reached 270 V, and if not, the timeout flag? FTOUT is set to 1 and the routine returns. When the time-out flag is set, charging is stopped in the charging control process.

<< Charge Prohibition Time Process >> FIG. 18 shows the S.MI 73 of the main process and the charge prohibition time process executed in the lock process described later. This process is a process of subtracting the set prohibition time data n when the camera is not used and the strobe is not used, thereby shortening the charging prohibition time TW.

If it is determined from the state of the FCNTSTP that the prohibition time reduction prohibition flag is prohibited, that is, if the charging prohibition time is being counted or the charging prohibition time has already been set to 0, the S.TC1 Also returns without performing the processing.

If the shortening is not prohibited, clear the flag. If the prohibition time data n is 0, return to S.TC5 with the prohibition time reduction prohibition flag set to 1 and subtract n from the next call. Set not to do so.

If the prohibition time data n is not 0, S.TC6 to TC12
In the above, a 4 second timer is used, and one is subtracted from n every 4 seconds.

That is, the reason why the subtraction of the inhibition time data n is not performed is n
Is 0 only.

<< Lock Process >> FIG. 19 shows a flow of a lock process branched from the S.MI 24 of the main process. This process is executed in a branched manner when the lock switch is turned on and the photographing lens is stored in the lock position.

In this process, the number display is turned on or off on the LCD according to the state of the loading end flag? LDEND in S.LK1 to LK4, and the mode is returned to the initial value.

S.LK5 ~ LK13 loop, rewind switch REW is OF
F, back cover switch BACK is OFF or ON
Even if the loading is completed, it is executed at 125ms repetition on condition that the loading is completed and the lock switch is ON.

In S.LK12 and LK13, the same charging prohibition time processing as in S.MI73 of the main processing is performed.

When the rewind switch is turned on, the process branches from S.LK6, executes rewind processing of S.LK61, and jumps to the beginning of the main processing.

When the back cover is closed and loading is completed, a loop is formed skipping S.LK9 and LK10, and when the back cover is opened, the loading end flag is cleared and the number display is turned off. Is done. Then, if the back cover is closed in the next loop, the process proceeds from S.LK8 to S.LK81 loading processing, and when this processing ends, jumps to the top of the main processing.

When the lock switch LOCK is turned off, S.LK14, LK15
Then, the charge request flag? CHGRQ and the display hold flag? WAITD are set to 1, and the process jumps to the main process to proceed.

When returning from the lock process to the main process, the main capacitor is often discharged, so if a strobe light emission is required at the first release after the power is turned on by issuing a charge request, wait for charging to be completed. Without having to deal with it quickly.

≪AEAF control processing≫ Next, based on FIGS. 20 to 22, the S.MI 65
The AEAF control processing related to the shutter control branched from FIG. This processing includes the photometric switch SWS as described above.
Changes from OFF to ON, and when the combination of modes is appropriate, it also enters after the process has branched to the release standby charging process once in this process, or after the wind in continuous shooting. This process is started from the terminals of AEAF control 2 and AEAF control 3, respectively.

First, in S.AF1 to AF3, the photometric distance measurement jump flag? AEAF is set according to which process has entered this flow. If the process branches to the release standby charging process in the middle of the AEAF control process and returns to this process again, since the detection of photometry, ranging, etc. has already been completed as described later, it is necessary to jump these processes. ? AEAF is set to 1, otherwise it is set to 0.

When branching from the main processing, this is set to 0 according to the state of the auto release flag? AUTOREL in S.AF, AF5.
, The focal length is displayed. This flag is set to 1 at the time of the second shooting in the interval mode or the double self mode as described later. In these cases, the flag is automatically set even if the photometry switch SWS and the release switch SWR are OFF. To execute shooting.

In S.AF6, a voltage check process described later is executed to measure the charging voltage of the main capacitor for the strobe.

In S.AF7, the charge request flag? CHGRQ set in the FM calculation described later is set to 0.

In S.AF8 to AF11, when the flow is not the second one of the interval or the double self and enters this flow from the main processing and the wind processing, distance measurement data is input from the sub CPU and LL ( (Lens Latch) calculation.

In cases other than the above, the previous LL data is used as it is, and therefore, in the case of interval shooting or the like, the focus is the same as the first image. This is because, in the case of interval shooting, it is general that the photographer is away from the camera, and it is necessary to prevent out-of-focus when the shooting target moves from the ranging area at the center of the screen.

The LL calculation is a calculation for determining a lens moving amount for performing focusing based on a distance measurement result. In the LL operation, when the lens is in the zoom range and the subject is at a short distance, the green lamp blink flag? GLMPFL for warning is set to 1 and the release lock flag? RLOCK is set to 1. When the lens is at the macro position and the subject is at a long distance, the macro teleshift flag? MTSIFT is set to 1 in addition to the above two flags.

In S.AF12 to AF16, photometry-related processes are executed except when the AEAF process is started again from the release standby charging process once branched.

In other words, S.AF13 inputs the DX code and
The ISO sensitivity is converted into an Sv value used for calculation, and in S.AF14, the correction amount α of the open F-number is obtained from the focal length of the lens.
Based on these data and the photometric data input from the sub CPU in S.AF15, the AE
(Automatic exposure) Performs arithmetic processing to obtain AE data.

In S.AF17, FM (flashmatic) shown in Fig. 24
The arithmetic processing is called, and the FM data is set. Note that if this processing is entered again from the release standby charging processing that has branched once, the AE calculation is skipped.
Since the DGV may have changed, the FM calculation is executed again.

Next, in S.AF18, the release lock flag? RLOCK is determined in S.AF11 whether the release lock is determined during the LL operation.
Judgment from the state of. Release lock is determined when the lens is in the zoom range and the subject is too close, and when the lens is in the macro position and the subject is too far. In these cases, a focused photograph cannot be obtained, so a warning is given by flashing the green lamp in S.AF19 to AF21, and red is waited until the photometry switch SWS is released,
Turn off the green lamp and jump to the main processing.

In S.AF22-AF24, if the charging voltage of the strobe capacitor has not reached the specified value and there is a charging request, the condition must be that the camera is not in the interval mode or that the first shot is taken even in the interval mode. The process then branches to the release wait charging process of FIG. That is, in the second and subsequent sheets of the interval, even if the charging voltage has not reached the predetermined value, light emission is performed only for the charged amount, and the following release sequence is executed.

In the interval, as shown in FIG. 27, the charge control is performed for each single photographing. If the control does not reach the predetermined value, the voltage is unlikely to increase even if the charging process is executed again. Because.

In S.AF25 to AF27, each set data is
Output to U.

Then, in the case of automatic shooting, the lamp display, photometry, and the release switch determination are skipped and “AFA” in FIG. 21 is skipped.
Jump to. During normal shooting other than the automatic shooting mode, the red lamp is turned on when the strobe is fired based on the FM data in S.AF29 and AF30, and the process proceeds to “AFB” in FIG.

In S.AF31 to AF33, the green lamp is turned on or blinks based on the green lamp blink flag? GLMPFL set inside the LL operation. Here, the lighting of the green lamp indicates that the photographing is permitted, and the blinking of the green lamp indicates a warning.

In S.AF34 and AF35, wait for the release switch SWR to be turned on on condition that the photometry switch SWS is kept turned on.If the hand is released from the shutter button, the S.AF34
Turn off the red and green lamps in a and jump to the main processing.

For S.AF36 to AF43, start the 3s timer for the first shot of interval shooting, start the 10s timer for the self-timer or the first shot of double self, and for the second shot in double self mode Start the 5s timer.

In the case of the second and subsequent sheets of the interval, since the interval timer has already been activated, the processing directly proceeds to the time-up wait processing after S.AF44, and when neither the interval nor the self mode is set, "AFC" in FIG. Jump to

S.AF44 to AF54 are the above interval timer, 10s,
This is a loop that waits for the 5s and 3s timers to time up.In addition to the time up, you can exit by operating the mode button.In this case, the S.AF55, AF56 switches the red, green lamp, and self-timer lamp. After turning off the light and clearing the automatic shooting flag to initialize the mode,
Jump to main processing.

After the second interval, the remaining time of the interval timer is displayed.

When the remaining time of the interval timer or the 3s, 5s, 10s timer is within 3 seconds, the self-timer lamp blinks at 4 Hz.

When the time is up, based on the judgment in S.AF57 and AF58, the auto release flag? AUTOREL is inverted by S.AF59 in the case of the self-timer or S.AF59 in the case of double self based on the judgment of A. Proceed to. In the case of double self, the flag is changed from 0 to 1 in the first photographing, and is returned from 1 to 0 in the second photographing to cancel the automatic photographing.

In the case of an interval, the interval timer is started at the interval time set in S.AF60 to AF64, and the maximum number of shots is set to 40 for the first shot.
The auto release flag? AUTOREL is set to 1 in order to automatically take the second and subsequent shots. When shooting the second and subsequent shots, set the remaining interval display on the LCD display to "0".
s ”and proceed to“ AFC ”in FIG. The processing of S.AF64 is performed in order to prevent the display from returning to a number other than 0 due to the expiration of the timer.

In S.AF65 to AF67 in Fig. 22, each lamp display is turned off before starting exposure, and the shutter start signal is
Output to U. In S.AF68 and AF69, date imprinting is prohibited in the case of multiple shooting.

If not in valve mode, branch off from S.AF70 to S.AF
In step 71, it is confirmed that a shutter operation end signal is input from the sub CPU, and the flow advances to a wind process in FIG.

When in the valve mode, check that the shutter release signal is input from the sub CPU in S.AF72, and
It is determined whether the shutter is an original valve or a manual shutter. For valves, S.AF74, AF75
Wait until the shutter button is released and press the S.AF76
Outputs a shutter close signal. If the shutter is a manual shutter, the manual shutter time is counted by S.AF77, and a shutter close signal is output after the count is completed.

<< Voltage Check Process >> FIG. 23 shows a voltage check process called in S.AF6 of the AEAF control process.

In S.VC1 to VC4, after setting the voltage check signal CHCK to H, wait for 50 ms in consideration of the rising of the Ne tube, and
Execute the pulse time measurement process, and then check the voltage check signal CH
Let CK be L.

In S.VC5 to VC7, if the charging voltage is 270 V or more and double self or interval operation is in progress, the prohibition time reduction prohibition flag? FCNTSTP is cleared, otherwise, the process proceeds to S.VC8 as it is . Therefore, the reduction of the prohibition time is not performed during the double self and the interval operation.

After that, charging flag? FCHG and charging completion flag in S.VC8
Clear both FCCMP and return to AEAF control processing.

In addition, the charging voltage 270V established in this voltage check
The flag? FCHG270 sets a charge request flag? CHGRQ in the FM operation described later, thereby branching to the release standby charging process.

<< FM Calculation Processing >> FIG. 24 shows the FM calculation processing called in S.AF17 of the AEAF control processing.

In this process, the strobe light emission and non-light emission are determined, and the aperture value Avs at the time of light emission is determined.

For S.FM to FM5, the exposure method is strobe off, exposure compensation,
In the case of a valve, or in the case of auto and non-light emission in the AE calculation processing, the process returns to the AEAF control processing with the FM data as non-light emission.

In cases other than the above, the aperture value Avs is obtained from the distance measurement data (AF step) and the reference guide number using S.FM6.
At S.FM7, the aperture value Avs is corrected in consideration of the charging voltage information DGV. This is because the guide number is set on the basis of the time when the strobe capacitor is fully charged, so that the exposure becomes underexposed unless the reduction of the guide number when the voltage is low is taken into account.

In S.FM8, film sensitivity Sv is added to aperture value Avs, and S.FM
9, FM10 adds the amount of change ZDGV of the guide number due to zooming of the strobe itself when in the zoom range.

Furthermore, in S.FM11, the open F based on the focal length of the lens
The change amount α of the number is subtracted from the aperture value Avs.

In S.FM12 to FM14, the upper limit and lower limit of the aperture value Avs are limited, and based on the result of the voltage check process called in S.FM6 of the AEAF control process, when the voltage of the strobe capacitor is 270 V or less. The charging request flag? CHGRQ is set to 1 and the routine returns.

<< Release Waiting Charge Processing >> FIG. 25 shows the release wait charging processing branched from S.FM23 and AF24 of the AEAF control processing.

S.CH1 to CH9 are loops for repeatedly executing the charge control of S.CH6 at a cycle of 125 ms, and the time is up from the time-up flag? FCHTUP and the 280V charge flag? FCH280 that are set during this charge control process. Or charge voltage 280
If it is judged to be V or more, it can escape.

In the case of automatic shooting such as interval mode, it is possible to exit to S.CH10 by turning on any one of the mode switches (mode button A, mode button B, clear button C). The button 15 can be released when the hand is released.

If the charging voltage does not reach 280 V within 6 seconds and the time is up, the release waiting charging process can be exited. In the case of these escapes, the red and green lamps are turned off in S.CH10 to CH12, and a charging stop process is performed.
Cancel automatic shooting and jump to main processing.

When the charging voltage reaches 280 V before the time is up, the process proceeds to S.CH14 to CH16 through the charging stop process of S.CH13,
If the mode is not the automatic shooting mode, the red lamp is turned on to indicate that the flash is ready, and a charge request flag is displayed.
Clear? CHGRQ and jump to AEAF control 2 in Fig. 20. When the AEAF control is started from this processing, the photometry and the distance measurement are omitted as described above, and the calculation is performed using the previous data.

The voltage check during charging is based on 280 V, and the voltage check after charging is based on 270 V in consideration of the voltage drop due to the stop of charging, noise, and the like.

In the charging control performed in the main processing, the charging voltage is 330 V
The charging is completed at, and the time up is monitored in 8 seconds.
However, in the release standby charging process, since the photographer is in a state of waiting for the charging to be completed while pressing the photometric switch SWS, the charging is completed at the charging voltage of 280 V, and the time-up is monitored in 6 seconds. . Therefore, S.CC of charge control processing
Since the charge request? CHGRQ is not cleared at 10, it is cleared at S.CH16.

<< Wind Processing >> FIG. 26 shows a winding processing to be shifted after the AEAF control processing is completed.

The wind process is a process for winding the film by one frame after the photographing is completed.

When the winding process starts, the number of images is displayed on the LCD display except for the interval in S.WD1 and WD2. In the case of multiple shooting, the shooting direction branches from S.WD3 to S.WD4 and the shooting direction is returned to single-frame shooting. Jump to main processing. That is, the multiple shooting is cleared each time.

In cases other than the multiple shooting, winding is performed by one frame in S.WD5. If the winding is not completed within a predetermined time, the flow branches from S.WD6 to S.WD7 to clear the flag of the automatic shooting, and the S.WD5 is cleared. Perform rewind processing of WD71 and jump to main processing.

When the winding is completed, the number counter is counted up in S.WD8, and a new number count is displayed in S.WD9 and WD10 unless the interval is reached. The reason why the number display is not executed in the case of the interval is that the remaining time until the next image is subtracted during the interval image capturing as described later.

In S.WD11 to WD15, the branch destination after the wind processing is determined according to the set imaging method.

First, in the case of continuous shooting, if the shutter button is kept pressed, the flow jumps to AEAF control 3 in FIG. 20 to continue the exposure sequence, and if the button is released, the flow jumps to the main processing.

Next, in the case of double self, when the first image is completed, the process jumps to the AEAF control again, and when the second image is completed, the process jumps to the main processing.

If it is in the interval, the process jumps to the interval control process in FIG. 27. If it is not in any of the above modes, that is, in the case of single-frame shooting or the self-timer, it jumps to the main process.

<< Interval Control Process >> FIG. 27 shows an interval control process for shifting from the S.WD 15 of the above wind process. This process is performed when the shooting method is set to interval.
This is a process of waiting while measuring the time until the shooting of the second frame. In the case other than the interval, the processing is usually executed in a loop within the main processing, but in the case of the interval, the processing is executed in a loop between the AEAF control processing and the interval control processing without going through the main processing Is done.

In this process, the charge request flag? CH
Clear both the GRQ and the charge request memory flag? CHGRQM.

In S.IN2 and IN3, the count of the number of interval sheets is subtracted to determine whether or not the count has become 0. The initial count value is 40 sheets set in S.AF62 of the AEAF control processing. When the photographing of 40 images is completed, the charging stop processing is performed in S.IN4 to IN6, the automatic photographing flag is cleared, and the mode jumps to the main processing after executing the mode initializing processing.

If the sheet count is not 0, S.IN7
Steps IN21 to IN21 are looped at a cycle of 125 ms, and waits for the next shooting. If any one of the mode switches or the clear switch is turned on during that time, the mode is initialized and the process jumps to the main processing.

During this loop, the timer is normally displayed with a subtraction display, but when the photometry switch is turned on, the number of sheets is displayed, and when the zoom telephoto or wide switch is turned on, the focal length is displayed.

When the remaining time is less than 16 seconds,? CHGRQ ,?
CHGRQM is both set to 1. This timer is AEAF
It is set and started in S.AF60 of control processing.

In the charging control of S.IN20, charging is performed when? CHGRQ is 1, and it is passed as it is when? CHGRQ is 0.

Therefore, when going through the loop of S.IN17 to IN20, charging is forcibly started in the first loop, and when it is detected that charging has been sufficiently performed, charging is stopped, and the next The charge control is passed from the loop.

When the remaining time is less than 4 seconds, branch from S.IN19 and S.IN19.
The charging is stopped and the remaining time of the timer is displayed at IN22 and IN23, and the process jumps to the AEAF control process of FIG. 27 and waits until the time is up in S.AF44 to AF54 of this process.

Finally, the relationship between the constituent elements of the invention described in claims 1 to 3 and the corresponding parts of the above embodiment will be described.

The “pulse output means” in claim 1 corresponds to the voltage detection circuit described in FIG. 5 and the corresponding description (page 12). The voltage detection circuit is a Ne tube, transistors Tr3, Tr
4. RLS pulse composed of resistors R4 to R8 and capacitor C3, RLS pulse corresponding to charging voltage only when the change of voltage check signal CHCK from H to L is input and charging voltage exceeds a predetermined reference voltage Is output.

Also, the Ne tube does not light unless the charging voltage becomes 270 V or more, in which case no pulse is output.

The "voltage measuring means" in claim 1 corresponds to the CPU in FIG. In accordance with the RLS pulse time measurement processing shown in FIG. 16, the CPU divides the charging voltage into five stages corresponding to the time width of the RLS pulse, and sets a parameter DGV indicating the correction amount of the guide number according to this. I have.

The "reference voltage" of claim 1 is 270 V, which is the lighting start voltage of the Ne tube, and is set as the minimum voltage for permitting strobe light emission. That is, when the Ne tube is lit, the flag? FCH270 indicating that the charging voltage is 270 V or more in S.RL16 and S.RL20 in FIG. 16 is set to 1, which is the condition for strobe light emission.

The "switch means" of claim 1 is a transistor Tr3 constituting the voltage detection circuit of FIG. 5, and the "hysteresis element" is N
The e-tube and the "compensation means" correspond to the capacitor C3. As described in the embodiment, the energization start voltage of the Ne tube is 270 V, the energization voltage is 220 V, and the voltage of the main capacitor C1 is applied by turning on the transistor Tr3. Also,
After the transistor Tr3 is turned off, the current from the Ne tube flows to the capacitor C3, during which the current supply to the Ne tube is compensated. While energization is compensated, transistor Tr4 turns on and RLS goes low.
Becomes As the charging of the capacitor C3 progresses, the potential of the resistor R4 on the capacitor C3 side gradually increases, and the current necessary to maintain the lighting of the Ne tube cannot flow. As a result, the Ne tube is turned off, and no current flows from the resistor R4 to the capacitor C3, so that the transistor Tr4 is turned off and RLS becomes H. The time during which the current supplied by the capacitor C3 is compensated and the RLS becomes L is the "time during which the current is compensated" in claim 1, and the L level of the RLS is a "pulse corresponding to time".

Claims 2 and 3 define the configuration of the embodiment as described above.

[Effect] As described above, according to the strobe control device according to the first aspect, the charging voltage of the main capacitor of the strobe can be detected at a fine level with a relatively simple configuration, and for example, according to the charging voltage. Exposure control can be performed according to the amount of light emission, and a pulse is output only when the charging voltage exceeds a predetermined reference voltage.This reduces the possibility of erroneous determination when measuring the pulse time. Yes, the strobe can already emit light when performing pulse time measurement, so even if the pulse time measurement is incorrect, avoid the situation where the strobe should not emit light if the strobe should be fired. be able to.

[Brief description of the drawings]

The drawings show a camera equipped with a flash control device according to the present invention. 1 to 3 show the appearance of the camera. FIG. 1 is a plan view, FIG. 2 is a front view, and FIG. 3 is a rear view. FIG. 4 is a block diagram of a control circuit, FIG. 5 is a circuit diagram related to a strobe light, FIG. 6 is a timing chart of voltage check, and FIG. 7 is a graph showing a relationship between RLS pulse time and voltage. 8 to 27 are flowcharts showing the functions of the camera provided with the strobe control device of this embodiment. FIG. 8 is a reset process, FIGS. 9, 11, 12, and 13 are main processes, and FIG. Is a loop exit process, FIG. 14 is a charge control (including charge stop process) process, FIG. 15 is a charge prohibition process, FIG. 16 is an RLS pulse time measurement process, FIG. 17 is a timeout check process, and FIG. Prohibition time reduction processing, FIG. 19 shows lock processing, FIGS. 20, 21, and 22 show AEAF control processing, FIG. 23 shows voltage check processing, FIG. 24 shows FM calculation processing, FIG. 25 shows release standby charging processing, and FIG. The figure shows a wind process, and FIG. 27 shows an interval control process. 1 Camera body 2, 3 Zoom lens barrel 4 Distance measuring unit 5 Finder window 6 Strobe CdS Photometric light receiving element 7 Self-timer lamp 8 Back cover 9 LCD display 10 Zoom lever A, B Mode button C Clear button D Green lamp E Red lamp 11 Back cover open lever 14 Power lever 15 Shutter button 16 Macro Button LOCK Lock switch SWS Photometry switch SWR Release switch MCRO Macro switch TELE Zoom tele switch WIDE Zoom wide switch MDA Mode A switch MDB Mode B switch MDC Clear switch BACK …… Back cover switch REW …… Rewind switch

Continued on the front page (72) Inventor Yasushi Tabata 2-36-9 Maenocho, Itabashi-ku, Tokyo Asahi Optical Industry Co., Ltd. (72) Inventor Norio Numako 2-36-9 Maenocho, Itabashi-ku, Tokyo Asahi In Optical Industry Co., Ltd. (72) Inventor Katsutoshi Nagai 2-36-9 Maeno-cho, Itabashi-ku, Tokyo Asahi Optical Industry Co., Ltd. (56) References JP-A-58-75133 (JP, A) JP-A-1 JP-A-188840 (JP, A) JP-A-60-143328 (JP, A) JP-A-58-97031 (JP, A) JP-A-61-296336 (JP, A) JP-A-63-104035 (JP, A) ) Japanese Utility Model Showa 57-176025 (JP, U) Japanese Utility Model Showa 50-12724 (JP, U) Japanese Patent Publication No. 52-6621 (JP, B1) Japanese Utility Model Showa 52-47482 (JP, Y1)

Claims (3)

(57) [Claims] 1. A pulse output means for outputting a pulse having a time width corresponding to a charging voltage of a main capacitor when a voltage check signal for checking a charging voltage of a main capacitor for a strobe is inputted, Voltage measuring means for measuring a time width to detect the charging voltage, wherein the pulse output means outputs a pulse only when the charging voltage exceeds a predetermined reference voltage. A switch means for turning on / off based on a voltage check signal for checking the current, and a voltage at which the power supply start voltage and the power supply voltage are different. A hysteresis element to which the voltage of the main capacitor is applied; and the switch means is turned on while the hysteresis element is energized.
And a compensating means for compensating the energization of the hysteresis element until the energization current to the hysteresis element decreases to the energization holding current after turning off. A strobe control device that outputs a corresponding pulse and the reference voltage is a strobe light emission permission voltage. 2. A strobe control device according to claim 1, wherein said hysteresis element is a neon tube. 3. The strobe control device according to claim 1, wherein said compensation means is a capacitor.