JPH0477298B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a light emission control device for an auto strobe, and more particularly, to an auto strobe equipped with a plurality of flash discharge tubes. Regarding equipment.

As is well known, the light emission characteristics of flash discharge tubes in strobes have an extremely rapid rise.
Furthermore, as the guide number increases, the maximum value of the emitted light flux increases. For this reason, when using an auto strobe to take flash photography of a subject at a close distance, automatic light adjustment is performed near the point where the flash discharge tube's radiant flux reaches its maximum luminous flux, so the flash stop time is shortened. There was a problem in that even a small deviation caused a large exposure error. In order to reduce such exposure errors, strobes have already been proposed in which an inductance element is inserted in series in the discharge path to slow the rise of the emitted light flux and keep the maximum value low ( Tokuko Showa 51-
(See Publication No. 23907). However, such a strobe has the disadvantage that a large energy loss occurs because an inductance element is inserted into the discharge path.

The above-mentioned exposure error caused by the automatic light adjustment of the auto strobe becomes even more significant in the case of an auto strobe with a large amount of light that is equipped with a plurality of flash discharge tubes. In other words, in conventional auto strobes of this type, multiple flash discharge tubes were made to emit light at the same time using one light emission starting circuit, so the rise of the emitted light flux became more rapid and its maximum value also increased. This resulted in a slight deviation in the automatic light control timing resulting in a large exposure error.
That is, as shown in Fig. 1, there is a dimming characteristic curve a 1 when two flash discharge tubes are emitted at the same time and their emission is stopped at time t ₁ , and a dimming characteristic curve a ₁ when only one lamp is emitted and their emission is stopped at time t 1. Compared to the dimming characteristic curve b ₁ when the light emission is stopped at ₁ , the rise of the curve a ₁ is more rapid and the maximum value is larger. Therefore, when two lights are emitted simultaneously, a larger error occurs in the shaded area than when one light is emitted. Also, this error increases as time t ₁ becomes earlier.
In other words, the closer the subject is, the smaller the overall amount of light emission becomes, which becomes more noticeable.

FIG. 2 shows the overexposure and underexposure characteristics with respect to the subject distance in the case of simultaneous light emission of two flash discharge tubes and in the case of one light emission, respectively. Comparing the characteristic curve a ₂ in the case of two lamps firing at the same time and the characteristic curve b ₂ in the case of one lamp firing, it is found that when the subject is closer than the distance L, the characteristics of curve b ₂ are better. , it can be seen that when the subject is farther away than the distance L, the characteristics of curve _a2 are better. Therefore, in a strobe equipped with two flash discharge tubes, only one flash should be emitted when the subject distance is less than L, and both lights should be emitted when the object distance is greater than or equal to L. This is desirable, and in this way, it becomes possible to realize a strobe that has the short-distance characteristics of single-flash emission, but can obtain the light amount of dual-flash emission when the subject distance is long.

By the way, some strobes equipped with multiple flash discharge tubes do not cause the flash discharge tubes to emit light at the same time, but rather stagger their emission start times so that the first flash discharge tube emits light. It is already known that when sufficient illumination light is obtained, the second and subsequent flash discharge tubes do not emit light, thereby suppressing wasteful energy consumption (Japanese Patent Publication No. 47-34332). (see publication). However, this strobe was not an auto strobe, and even though it did not have automatic flash control, it had the disadvantage that it was not possible to check whether the second flash discharge tube and subsequent flash tubes would emit light before taking a picture. . In other words, when taking flash photography using a regular strobe, it is necessary to decide the aperture value, shutter speed, etc. according to the strobe's guide number and subject distance. There was an inconvenience that these could not be determined because they were not determined. This inconvenience becomes especially noticeable when photographing a subject at an intermediate distance, which is the boundary between whether or not the second flash discharge tube will emit light, and there is a risk of taking an incorrectly exposed photograph. It was big.

In view of the above-mentioned points, it is an object of the present invention to cause a plurality of flash discharge tubes to emit light by staggering their light emission start timings, and to enable a plurality of flash discharge tubes to emit light when a sufficient amount of light is obtained in the middle of light emission from some of the flash discharge tubes. Another object of the present invention is to provide a light emission control device for an auto strobe that automatically stops the light emission of the same discharge tube and at the same time prevents the light emission of other flash discharge tubes.

Hereinafter, the present invention will be explained based on illustrated embodiments.

FIG. 3 shows an electric circuit of an autostroboscopic light emission control device showing an embodiment of the present invention. This electric circuit is provided with a power supply circuit _P1 including a well-known DC-DC converter.
Positive operating voltage supply lines _l1 and _l2 are led out from the positive output of the circuit _P1 via backflow prevention diodes _D1 and _D3 , respectively.
Further, a common ground line _l0 is drawn out from the negative output terminal of the power supply circuit _P1 . Above line l ₁ ,
An operating voltage of several hundred volts is supplied from the power supply circuit P ₁ between l ₀ and between l ₂ and l ₀ .

A first main capacitor C ₁ is connected between the above lines l ₁ and l ₀ , and in parallel with the capacitor C ₁ , a resistor R ₁ and a synchronization contact SW ₁ arranged across the camera are connected. A series circuit is connected. The connection point between the resistor R ₁ and the synchro contact SW ₁ is connected to the input terminal of the trigger circuit A1 that generates the trigger signal for the main thyristor SCR ₂ , and is also connected to the line l ₀ through the resistor R ₂ to the trigger capacitor C. ₂ connected to the cathode of the trigger thyristor SCR ₁ respectively. The anode of the trigger thyristor SCR ₁ is connected to the line l ₁ through a resistor R ₃ and to one end of the primary coil of the trigger transformer T ₁ through a trigger capacitor C ₃ . The cathode of the trigger thyristor SCR ₁ is also connected to the line l ₀ through a diode D ₂ , and the gate is connected to the cathode of the same thyristor SCR ₁ through a resistor R ₄ , as well as through a resistor R ₅ .
Connected to line _L0 through. One end of the secondary coil of the trigger transformer T ₁ is connected to the trigger electrode of the first flash discharge tube X ₁ , and the other ends of the primary and secondary coils of the transformer T ₁ are
Connected to line l ₀ .

Said flash discharge tube X ₁ has an anode connected to line l ₁ and a cathode connected to line l ₀ through a parallel circuit of main thyristor SCR ₂ and resistor R ₆ . The main thyristor SCR ₂ has its gate connected to the output end of the trigger circuit A1, and its anode connected to the flash discharge tube X ₁ connected to the anode of the commutating thyristor SCR ₃ via a commutating capacitor _C4 . has been done. Commutation thyristor SCR ₃
has its anode connected to line l ₁ through resistor R ₇ and cathode connected to line l ₀ . Further, the gate of the thyristor SCR ₃ is connected to the output terminal of a trigger circuit B1 that generates a trigger signal for the thyristor SCR ₃ .

The above line l ₁ is connected to one end of the power supply capacitor C ₅ , and the other end of the same capacitor C ₅ is connected to the resistor R ₈
through the anode of the Zener diode ZD ₁ , and the cathode of the Zener diode ZD ₁ is connected to the line l ₀ . These capacitor C ₅ , resistor R ₈ and Zener diode ZD ₁ are:
A power supply circuit is formed that generates a constant voltage for a predetermined period of time after the flash discharge tube X ₁ emits a flash, and the circuit connected between the anode and cathode of the Zener diode ZD ₁ operates at a constant rate for the predetermined period. It is designed to supply voltage. A light control circuit C1 including a light metering circuit for metering light reflected from an object is connected between the anode and cathode of the Zener diode _ZD1 . This dimming circuit C1
is a circuit that outputs a 'H' level dimming signal when the reflected light from the subject reaches a predetermined level, and its output terminals are connected to the bases of NPN transistors _Q1 and _Q8 , respectively. There is. The collector of the transistor Q ₁ is connected to the line l ₀ via resistors R ₁₂ , R ₁₁ , R ₁₀ in sequence, and the emitter is connected to the anode of the Zener diode ZD ₁ . The connection point between the resistors _R11 and _R10 is connected to the base of the PNP transistor _Q2 , whose emitter is connected to the line _l0 , and _whose collector is connected to the input of the trigger circuit B1 through the resistor _R9 . connected to the end. In addition, the connection point between the resistors _R12 and _R11 is connected to the resistor _R21 for preventing delayed ignition.
Connected to the base of PNP transistor _Q6 .

Transistor _Q6 above is a Zener diode
It is connected to the delayed ignition signal generation circuit formed between the cathode and anode of ZD ₁ . That is, the transistor _Q6 has its emitter connected to the line _l0 , and its collector connected to the connection point between the delay time adjustment variable resistor _VR1 and the resistor _R22 . variable resistance
VR ₁ has the other end connected to the anode of the Zener diode ZD ₁ , the resistor R ₂₂ has the other end connected to the line l ₀ , and an integrating capacitor C ₆ is connected in parallel with the resistor R ₂₂ . . This capacitor _C6 is
Creates light emission delay time with variable resistor VR ₁
They form a CR timer circuit, and the connection point between the two is
Connected to the base of PNP type transistor _Q5 . Transistor Q ₅ has its emitter connected to the connection point of resistors R ₁₉ and R ₁₈ inserted in series between the anode and cathode of Zener diode ZD ₁ , and its collector connected to the anode of Zener diode ZD ₁ through resistor R ₂₀ . is connected to the
Connected to the base of NPN transistor _Q4 . The transistor _Q4 has its emitter connected to the anode of the Zener diode _ZD1 , and its collector connected to the line _l0 via resistors _R17 and _R16 in sequence. The connection point between resistors R ₁₇ and R ₁₆ is
It is connected to the base of a PNP type transistor Q ₃ , and the emitter of the same transistor Q ₃ is connected to the line l ₀
, the collector is connected to the anode of the Zener diode ZD ₁ via resistors R ₁₃ , R ₁₄ , and R ₁₅ in sequence. Connection point and resistance between the above resistors R ₁₃ and R ₁₄
The connection point between R ₁₄ and R ₁₅ forms the output end of the delayed ignition signal generation circuit.

The connection point between the resistors R ₁₃ and R ₁₄ is connected to the gate of the ignition thyristor SCR ₄ which serves as a synchro contact for the second flash discharge tube X ₂ , and the connection point between the resistors R ₁₄ and R ₁₅ is The point is connected to the cathode of the thyristor SCR ₄ above. This thyristor SCR ₄ has an anode connected to the line l ₂ through a resistor R ₂₃ and a cathode connected to the line l ₀ through a diode D ₄ , and the series circuit consisting of the resistor R ₂₃ , the thyristor SCR ₄ , and the diode D ₄ is , connected in parallel with a second main capacitor C ₇ connected between lines l ₂ , l ₀ . Also, the anode of thyristor SCR ₄ is connected to the main thyristor
It is connected to the input end of the trigger circuit A2 which generates the trigger signal for SCR ₆ , and is also connected to the line _l0 through a resistor _R24 and to the cathode of the trigger thyristor _SCR5 through a trigger capacitor _C8 . The anode of the trigger thyristor SCR ₅ is
It is connected to line l ₂ through a resistor R ₂₅ and to one end of the primary coil of a trigger transformer T ₂ through a trigger capacitor C ₉ . In addition, the cathode of the trigger thyristor SCR ₅ is connected to the line l ₀ through a diode D ₅ , and the gate is connected to the cathode of the same thyristor SCR ₅ through a resistor R ₂₆ and to the line l ₀ through a resistor R ₂₇ . It is connected. Above trigger transformer T ₂
One end of the secondary coil of is connected to the trigger electrode of the second flash discharge tube X ₂ , and one end of the secondary coil of the transformer T ₂
The other ends of the primary and secondary coils are connected to line l ₀ .

Said flash discharge tube X ₂ has its anode connected to line l ₂ and its cathode to line l ₀ through a parallel circuit of main thyristor SCR ₆ and resistor R ₂₈ . The main thyristor SCR ₆ has its gate connected to the output end of the trigger circuit A2, and its anode connected to the flash discharge tube X ₂ connected to the anode of the commutating thyristor SCR ₇ via a commutating capacitor _C10 . has been done. Commutation thyristor SCR ₇
has its anode connected to line l ₂ through a resistor R ₂₉ and its cathode to line l ₀ . Further, the gate of the thyristor SCR ₇ is connected to the output terminal of a trigger circuit B2 that generates a trigger signal for the thyristor SCR ₇ .

The above line _l2 is connected to one end of the power supply capacitor _C11 , and the other end of the same capacitor _C11 is a resistor.
It is connected through R ₃₃ to the anode of a Zener diode ZD ₂ , _whose cathode is connected to line l ₀ . these capacitors
C ₁₁ , resistor R ₃₃ and Zener diode ZD ₂ are
A power supply circuit is formed that generates a constant voltage for a predetermined period of time after the flash discharge tube X ₂ emits a flash, and the transistor Q ₈ and resistors R ₃₂ and R ₃₁ are connected between the anode and cathode of the Zener diode ZD ₂ . series circuit is connected. As described above, the transistor _Q8 has its base connected to the output terminal of the dimming circuit _C1 , its emitter connected to the anode of the Zener diode _ZD2 , and its collector connected to one end of the resistor _R32 . The connection point between the resistors R ₃₂ and R ₃₁ is connected to the base of the PNP transistor Q ₇ , and the emitter of the transistor Q ₇ is connected to the line l ₀
The collector is connected to the input terminal of the trigger circuit B2 through a resistor _R30 .

As described above, the autostroboscopic light emission control device of this embodiment is configured.

Next, the operation of this light emission control device will be explained.

First, when the synchro contact SW ₁ is closed by the camera, both ends of the trigger capacitor C ₂ are short-circuited through the synchro contact SW ₁ - resistor R ₅ - the gate and cathode of the trigger thyristor SCR ₁ , and the trigger thyristor SCR ₁ is closed. It is ignited by the discharge current of capacitor _C2 . Then, the charge in the trigger capacitor C ₃ is discharged through the thyristor SCR ₁ - the diode D ₂ - the primary coil of the trigger transformer T ₁ , and the high voltage generated in the secondary coil of the transformer T ₁ is applied to the trigger electrode. Flash discharge tube X ₁ becomes excited. Meanwhile, at the same time, synchro contact SW ₁ is closed, causing the input terminal of trigger circuit A1 to go to 'L' level, and the circuit A1 operates to bring the gate of main thyristor SCR ₂ to 'H' level. trigger. As a result, the same thyristor SCR ₂ is turned on. Therefore, the charge accumulated in the main capacitor C ₁ is rapidly discharged through the flash discharge tube X ₁ - main thyristor SCR ₂ , and the flash discharge tube
X ₁ starts flashing.

When flash discharge tube X ₁ starts flashing, the charge stored in capacitor C ₅ is
Discharge occurs through X ₁ - main thyristor SCR ₂ - Zener diode ZD ₁ - resistor R ₈ , and a constant voltage is generated between the cathode and anode of Zener diode ZD ₁ . Therefore, the dimming circuit C ₁ is supplied with an operating voltage and starts operating, and at the same time, charging of the capacitor C ₆ through the variable resistor VR ₁ is started. Then, after a predetermined delay time has elapsed, the charging voltage of capacitor C ₆ , that is, the base potential of transistor Q ₅ , becomes
When the divided voltage generated at the connection point of resistors R ₁₉ and R ₁₈ becomes lower than the emitter potential of transistor Q ₅ by the barrier voltage V _BE between the base and emitter of transistor Q ₅ , transistor Q ₅ is turned on. Then transistors Q ₄ and Q ₃ are also turned on and resistor R ₁₄
The voltage generated across the thyristor SCR ₄ is applied between the gate and cathode of the thyristor SCR 4. Therefore, the thyristor SCR ₄ serving as a synchronizing contact for _{the second flash discharge tube X 2 is} turned on, and the second flash discharge tube Flash discharge tube X ₂ starts emitting light.

After that, when the reflected light from the subject reaches the appropriate amount of light and a "H" level dimming signal is output from the dimming circuit C1, transistors _Q1 and _Q8 are turned on.
Transistors Q ₂ and Q ₇ are turned on, trigger circuits B1 and B2 are activated, and the commutating thyristor
The gates of SCR ₃ and SCR ₇ are each triggered to "H" level. Thus, thyristors SCR ₃ and SCR ₇ are fired simultaneously, commutating capacitor C ₄
and C ₁₀ charges on thyristors SCR ₃ and SCR ₇
between the anodes and cathodes of the main thyristors SCR ₂ and SCR ₆ and between the cathodes,
The gates are reverse biased. Therefore, the main thyristors SCR ₂ and SCR ₆ are abruptly turned off, and the flash discharge tubes X ₁ and X ₂ stop emitting light.

By the way, the above explanation of the operation is for the case where the dimming signal is output after the second flash discharge tube X ₂ emits light, but when the subject is at a short distance,
If the dimming signal is output before the second flash discharge tube X ₂ emits light, the second flash discharge tube X ₂
will not emit light as it is. That is, if the dimming signal is output from the dimming circuit C1 before the delay time created by the timer circuit consisting of the variable resistor VR ₁ and the capacitor C ₆ has elapsed, the commutating thyristor SCR ₃ is ignited to stop flash discharge tube X ₁ from emitting light, and the transistor
When Q ₁ is turned on, “L” is applied to the base of transistor Q ₆ .
When a level signal is applied, the same transistor _Q6 turns on and both ends of the capacitor _C6 are shorted. The timer circuit is therefore inactive and the thyristor SCR ₄ , which serves as a synchronizing contact for the second flash discharge tube X ₂ , is no longer fired.
Flash discharge tube X ₂ is not emitted.

Note that only after the first flash discharge tube X ₁ emits light,
Since the delayed ignition signal generation circuit operates, there is no possibility of a malfunction in which only the second flash discharge tube _X2 emits light.

As described above, according to the autostroboscopic _light emission control device of this embodiment, as shown in FIG. ₄ , the light emission of the _first flash discharge tube Since the second flash discharge tube _X2 emits light (see curve _d2 ), the strobe exhibits light emission characteristics as shown by curve d. This characteristic curve d has a gradual rise and a smaller maximum value than the characteristic curve c when two flash discharge tubes X ₁ and X ₂ are lit at the same time. It has almost the same short-range characteristics as (see ₁ ). Therefore, even if the subject distance is short and the flash is automatically adjusted in a short time, the exposure error will be much smaller than when two flashes are fired simultaneously. In some cases, it is possible to obtain almost the same amount of light as when two lights are emitted simultaneously.

FIG. 5 shows an electric circuit of an autostroboscopic light emission control device showing another embodiment of the present invention.
The light emission control device of this embodiment is constructed in exactly the same manner as the device of the embodiment shown in FIG. 3, except for the delayed ignition signal generation circuit. Therefore, corresponding parts are given the same reference numerals and detailed explanations thereof will be omitted.

The delayed ignition signal generation circuit in the light emission control device of this embodiment includes a bistable multivibrator D1 that is set by detecting light emission from the first flash discharge tube _X1 .
The starting circuit D2 starts when the bistable multivibrator D1 is set, and the pulses output from the oscillation circuit D2 are counted, and when the number reaches a predetermined number, an "H" level signal is output. counter D3 and “H” of this counter D3
a delay circuit D4 that outputs a reset signal to the bistable multivibrator D1 and the counter D3 after a predetermined time has elapsed after receiving the level output;
An AND circuit D5 that shapes the waveform of the dimming signal output from the dimming circuit C1 and outputs it as a reset signal to the bistable multivibrator D1 and the counter D3, an NPN transistor _Q9 , and a resistor _R36 to
It consists of R ₄₁ and capacitor C ₁₂ .

The input end of the bistable multivibrator D1 is connected to the connection point of resistors R ₃₆ and R ₃₇ connected in series between the anode and cathode of the Zener diode ZD ₁ . The output end of this bistable multivibrator D1 is connected to the input end of an oscillation circuit D2.
One end of a capacitor C ₁₂ and a resistor R ₃₈ which determine the oscillation frequency of are connected respectively. The other ends of capacitor C ₁₂ and resistor R ₃₈ are connected to the line, respectively.
l Connected to ₀ . The output terminal of the oscillation circuit D2 is
It is connected to the input end of counter D3, and the output end of counter D3 is connected to the input end of delay circuit D4 and the base of transistor _Q9 , respectively. The transistor Q ₉ has its emitter connected to the anode of the Zener diode ZD ₁ , and its collector connected to the line l ₀ through resistors R ₃₉ , R ₄₀ , R ₄₁ in sequence.
It is connected to the. Further, the output terminal of the delay circuit D4 is connected to the reset signal input terminals of the bistable multivibrator D1 and the counter D3, respectively. Furthermore, the AND circuit D5 has the second
The two input terminals are connected together and connected to the output terminal of the dimming circuit C1, and the output terminals are respectively connected to the reset signal input terminals of the bistable multivibrator D1 and the counter D3. And a resistor R ₃₉ which becomes the output terminal of the delayed ignition signal generation circuit,
The connection point of R ₄₀ and the connection points of resistors R ₄₀ and R ₄₁ are connected to the cathode and gate of thyristor SCR ₄ , respectively.

In addition, in the apparatus of the embodiment shown in FIG.
Two resistors connected in series between the collector of transistor Q ₁ and the base of transistor Q ₂
R ₁₂ and R ₁₁ are replaced by one resistor R ₃₅ in the device of this embodiment.

In the auto strobe light emission control device of this embodiment configured as described above, the first flash discharge tube
X ₁ starts flashing and the Zener diode
When a constant voltage is generated between the cathode and anode of ZD ₁ , a divided voltage generated at the connection point of resistors R ₃₆ and R ₃₇ is applied to the input terminal of bistable multivibrator D1, and vibrator D1 is set. Then, “H” is output from this vibrator D1.
In response to the level signal, the oscillator circuit D2 connects the resistor R ₃₈
and begins oscillation at a constant frequency determined by capacitor _C12 . The oscillation pulse of the oscillation circuit D2 is input to the counter D3, and when the counter D3 has counted a preset number of counts, it outputs an "H" level signal to its output terminal. The above preset count number is calculated when the subject distance is L.
When only one flash discharge tube X ₁ is emitted,
It is selected to correspond to the time from light emission until the dimming circuit C1 outputs the dimming signal. The "H" level signal output from the counter D3 is applied to the base of the transistor _Q9 , turning on the transistor _Q9 . The voltage developed across the resistor R ₄₀ then acts as a delayed ignition signal to the thyristor.
A voltage is applied between the gate and cathode of SCR ₄ , and when the same thyristor SCR ₄ is turned on, flash discharge tube X ₂
starts emitting light. Further, the "H" level signal output from the counter D3 is input to the delay circuit D4, and after being delayed for a certain period of time by the same circuit D4, it is input to the reset signal input terminals of the bistable multivibrator D1 and the counter D3, respectively. applied. Therefore, the bistable multivibrator D1 and the counter D3 are reset and the vibrator D
1. The oscillation circuit D2 and the counter D3 return to their initial states.

When the amount of light reflected from the subject reaches the appropriate amount and the dimmer circuit C1 outputs a dimmer signal of the "H" level, a flash discharge occurs as in the case of the apparatus of the embodiment shown in FIG. 3 above. The light emission of tubes X ₁ and X ₂ is stopped.

By the way, if the subject is at a short distance and the dimming signal is output before the second flash discharge tube _X2 emits light, the second flash discharge tube _X2 will not emit light. That is, if a dimming signal is output from the dimming circuit C1 before the delay time created by the counter D3 elapses, the dimming signal is outputted as a reset signal via the AND circuit D5 to the bistable multivibrator D1 and the counter D3. Since the reset signal input terminals of the bistable multivibrator D1 and the counter D3 are reset before the output of the counter D3 is inverted, the transistor
_Q9 does not turn on. Therefore, the second flash discharge tube X ₂
is not emitted.

In this manner, the autostroboscopic light emission control device of this embodiment can also provide the same effects as the device of the embodiment shown in FIG. 3 above.

FIG. 6 shows an electric circuit of an autostroboscopic light emission control device showing still another embodiment of the present invention. The light emission control device of this embodiment has a delayed operation after a constant voltage is generated in the Zener diode ZD ₁ due to the start of light emission of the first flash discharge tube X ₁ . In contrast, by connecting the DC power supply _P2 to the delayed ignition signal generation circuit E1 in advance, the delay operation is started at the same time as the synchro contact _SW1 is turned on. .

The delayed ignition signal generation circuit E1 has a positive operating voltage supply end connected to the positive pole of the DC power supply _P2 , and a negative operating voltage supply end connected to the DC power supply _P2 through the line _l0 . Connected to negative pole. and,
The trigger terminal Tr of the delayed ignition signal generation circuit E1 is
It is connected to the connection point of the resistor R ₁ and the synchro contact SW ₁ , and the clear terminal Cl is connected to the output end of the dimming circuit C1. In addition, delayed ignition signal generation circuit E
The output terminal O of thyristor SCR _{4 is connected to the gate of thyristor SCR 4} . In the device of this embodiment, the diode _D4 (see FIGS. 3 and 5) is not inserted between the cathode of the thyristor _SCR4 and the line _l0 .

In the auto strobe light emission control device of this embodiment configured as described above, the synchro contact SW ₁
When the first flash discharge tube X1 is closed, the first flash discharge tube _X1 starts emitting light, and an "L" level signal is applied to the trigger terminal Tr of the delayed ignition signal generating circuit E1. Therefore, the delayed ignition signal generation circuit E1 starts a delay operation, and after a predetermined delay time has elapsed, the output terminal O
A delayed ignition signal of "H" level is output. Therefore, the thyristor SCR ₄ is fired and the second flash discharge tube X ₂ starts emitting light.

When the amount of light reflected from the object reaches the appropriate amount and the dimmer circuit C1 outputs a dimmer signal of "H" level, the flash discharge tube is At the same time as the light emission of X ₁ and X ₂ is stopped, a dimming signal is applied to the clear terminal Cl of the delayed ignition signal generating circuit E1, and the circuit E1 is reset to the initial state.

When the subject is close, the second flash discharge tube
If the dimming signal is output before _X2 is emitted, the delayed ignition signal generation circuit E1 is reset, so the delayed ignition signal at the "H" level will not be output from the output terminal O. Second flash discharge tube
X ₂ is not emitted.

In this manner, the autostroboscopic light emission control device of this embodiment can also provide the same effects as the device of the embodiment shown in FIG. 3 above.

FIG. 7 shows an example of a more detailed electric circuit of the delayed ignition signal generating circuit E1 shown in FIG. 6 above. The delayed ignition signal generation circuit E1 of this example is as follows:
A trigger signal input circuit consisting of a resistor R ₅₁ and a Zener diode ZD ₁₁ , a clear signal input circuit consisting of a capacitor C ₂₁ , a resistor R ₅₄ and a Zener diode ZD ₁₂ , a NAND circuit F1, and an AND circuit F ₂
, a bistable multivibrator F3, an oscillation circuit F4, a counter F5, a delay circuit F6, an OR circuit F7, a signal output circuit consisting of a resistor _R53 , a capacitor _C22 , and a resistor _R52 . ing. The trigger terminal Tr of this delayed ignition signal generation circuit E1 is
It is connected to the cathode of the Zener diode ZD ₁₁ through the resistor R ₅₁ , and the Zener diode
ZD ₁₁ has an anode grounded and a cathode connected to both input ends of the NAND circuit F1. The output end of the NAND circuit F1 is connected to the input end of the bistable multivibrator F3,
The output end of the vibrator F3 is connected to the input end of the oscillation circuit F4. One end of a capacitor C ₂₂ and a resistor R ₅₂ , which determine the oscillation frequency of the circuit F4, are connected to the oscillation circuit F4, and an operating voltage Vcc is applied to the other end of the capacitor C ₂₂ and the resistor R ₅₂ , respectively. has been done. The output end of the oscillation circuit F4 is connected to the input end of the counter F5, and the output end of the counter F5 is grounded via a resistor _R53 , and is also connected to the input end of the delay circuit F6. Above counter F5 and resistance
The connection point with _R53 is connected to the output terminal O of the delayed ignition signal generation circuit. The output terminal of the delay circuit F6 is connected to one input terminal of the OR circuit F7. On the other hand, the clear terminal Cl of the delayed ignition signal generation circuit E1 is connected to the cathode of the Zener diode ZD ₁₂ via a series circuit of a capacitor C ₂₁ and a resistor R ₅₄ , and the Zener diode ZD _{12 is connected to the cathode of the Zener diode ZD 12} .
The anode is grounded, and the cathode is connected to both input ends of the AND circuit F2. The output terminal of AND circuit F2 is connected to the other input terminal of OR circuit F7, and the output terminal of OR circuit F7 is connected to the reset signal input terminals of bistable multivibrator F3 and counter F5, respectively.

In the delayed ignition signal generation circuit E1 of this example configured in this way, in the initial state where the synchro contact SW ₁ (see Fig. 6) is open, the trigger terminal
An “H” level signal is applied to the Tr, and “H” is generated across the cathode of the Zener diode ZD ₁₁ .
A constant voltage of the same level is applied to both input terminals of the NAND circuit F1. That is, the "H" level signal applied to the trigger terminal Tr is converted by the Zener diode ZD ₁₁ to an appropriate voltage for the NAND circuit F1 etc. formed of an integrated circuit, and is applied to both input terminals of the NAND circuit F1. is applied to Therefore, in the initial state, the output terminal of the NAND circuit F1 is at the "L" level, and since the bistable multivibrator F3 is reset, the oscillation circuit F4 and the counter F5 are in an inactive state. Therefore, the output terminal O of the delayed ignition signal generation circuit E1 is at the "L" level. Next, when the synchro contact _SW1 is closed, the trigger terminal Tr becomes "L" level, and the output of the NAND circuit F1 is inverted to "H" level.
As a result, the bistable multivibrator F3 is set, the oscillation circuit F4 is activated, and the counter F3 is activated.
5 starts counting oscillation pulses. counter F5
After counting a preset number of counts, it outputs an "H" level signal to its output terminal. Therefore, a delayed ignition signal of "H" level is output to the output terminal O. Further, the "H" level output of the counter F5 is applied to the input terminal of the delay circuit F6, and the circuit F6 starts a delay operation. Then, when a predetermined delay time has elapsed, the delay circuit F6
An "H" level reset signal is output to the output terminal of the counter, and this reset signal is sent to the bistable multi-hibrator F3 and the counter F5 through the OR circuit F7.
is applied to vibrator F3 and counter F
5 is reset. So, vibrator F
3. The oscillation circuit F4 and the counter F5 return to their initial states.

Furthermore, if an "H" level dimming signal is applied to the clear terminal cl before the reset signal is output from the delay circuit F6, the capacitor C ₂₁ and the resistor R ₅₄
The differential pulse generated by the series circuit of is regulated by the Zener diode ZD ₁₂ , and
These signals are applied to both input terminals of the AND circuit F2. Therefore, a waveform-shaped "H" level pulse signal is output to the output terminal of the AND circuit F2, and this is sent as a reset signal to the reset signal input terminals of the bistable multivibrator F3 and the counter F5 through the OR circuit F7. applied. Therefore, vibrator F3 and counter F
5 is reset, and the vibrator F3, oscillation circuit F4 and counter F5 return to their initial states.

FIG. 8 shows another example of a more detailed electric circuit of the delayed ignition signal generating circuit E1 shown in FIG. 6 above. Delayed ignition signal generation circuit E1 of this example
are the resistors R ₆₁ , R ₆₂ and the NPN transistor Q ₁₁
A trigger signal input circuit consisting of a capacitor _C31 ,
Clear signal input circuit consisting of resistor R ₆₀ and Zener diode ZD ₂₁ , bistable multivibrator F8, resistors R ₆₃ to R ₆₅ , and NPN transistor Q ₁₂
and a time constant circuit consisting of a capacitor _C32 , and a comparison circuit consisting of a PNP transistor _Q13 and resistors _R66 to _R68 .

The trigger terminal Tr of the delayed ignition signal generation circuit E1 is
It is connected to the negative pole of the power supply P ₂ through a resistor R ₆₁ and to the base of the transistor Q ₁₁ . The transistor _Q11 has its emitter connected to the negative pole of the power supply _P2 , and its collector connected to the positive pole of the power supply _P2 through a resistor _R62 , as well as to the input terminal of the bistable multivibrator F8. The output end of the bistable multivibrator F8 is
It is connected to the negative pole of the power supply P ₂ through a resistor R ₆₃ and to the base of the transistor Q ₁₂ . The transistor _Q12 has its emitter connected to the negative pole of the power supply _P2 , and its collector connected to the positive pole of the power supply _P2 via a resistor _R64 and a capacitor _C32 in series. The connection point between the resistor R ₆₄ and the capacitor C ₃₂ is connected to the positive electrode of the power supply P ₂ via the resistor R ₆₅ and to the base of the transistor Q ₁₃ . The emitter of transistor _Q13 is a resistor
Connected to the connection point of R ₆₇ and R ₆₈ , resistor R ₆₇
The other end is connected to the positive pole of the power source P ₂ , and the other end of the resistor R ₆₈ is connected to the negative pole of the power source P ₂ . Further, the collector of the transistor _Q13 is connected to the negative electrode of the power supply _P2 through a resistor _R66 , and is also connected to the output terminal O of the delayed ignition signal generation circuit E1. On the other hand, the clear terminal Cl is connected to the cathode of the Zener diode ZD ₂₁ via a capacitor C ₃₁ and a resistor R ₆₀ in series.
ZD ₂₁ has its anode connected to the negative pole of power supply P ₂ and its cathode connected to the reset signal input terminal of bistable multivibrator F8.

In the delayed ignition signal generation circuit E1 of this example configured in this way, in the initial state where the synchro contact SW ₁ (see Fig. 6) is open, the trigger terminal
An "H" level signal is applied to the Tr, and the transistor _Q11 is turned on. Therefore, the input terminal of bistable multivibrator F8 is at "L" level, and vibrator F8 is in a reset state. Next, when the synchro contact SW ₁ is closed from this state, the trigger terminal Tr becomes "L" level,
Transistor _Q11 is turned off, and the input terminal of bistable multivibrator F8 becomes "H" level. Therefore, the vibrator F8 is set and an "H" level signal is output to its output terminal, turning on the transistor _Q12 and starting charging the capacitor _C32 through the resistor _R64 . Then, after a predetermined delay time has elapsed, the charging voltage of the capacitor C ₃₂ , that is, the base potential of the transistor Q ₁₃ , changes to the resistance R ₆₇ ,
The voltage divided by R ₆₈ , i.e. the base of transistor Q ₁₃ , is lower than the emitter potential of transistor Q ₁₃ .
When the emitter-to-emitter barrier voltage V _BE decreases, the same transistor Q ₁₃ turns on. As a result, a delayed ignition signal of "H" level is output to the output terminal O.
After that, when a "H" level dimming signal is applied to the clear terminal Cl, the differential pulse generated by the series circuit of the capacitor C ₃₁ and the resistor R ₆₀ is regulated in voltage by the Zener diode ZD ₂₁ , and becomes double It is applied to the reset signal input terminal of stable multivibrator F8. Therefore, bistable multivibrator F8 is reset and transistor _Q12 is turned off.
Transistor _Q13 is turned off and the output terminal O returns to the "L" level.

Note that if the dimming signal is applied to the clear terminal Cl before the predetermined delay time measured by the time circuit consisting of the capacitor C ₃₂ and the resistor R ₆₄ has elapsed, the signal will be applied to the clear terminal Cl before the transistor Q ₁₃ turns on. transistor to
Since _Q12 will be turned off, the transistor
_Q13 is never turned on, and no delayed ignition signal is output from output terminal O.

As described above, according to the present invention, in an auto strobe equipped with a plurality of flash discharge tubes, the firing start timing of the flash discharge tubes is staggered, and a sufficient amount of light is not produced during the firing of some of the flash discharge tubes. If a flash discharge tube is detected, the light emission of that flash discharge tube is automatically stopped, and at the same time, the light emission of other flash discharge tubes is also blocked. It exhibits dimming distance characteristics, and when the subject is far away, it is possible to obtain the amount of light emitted by a plurality of flash discharge tubes.

Therefore, it is possible to solve the conventional drawbacks mentioned at the beginning of the specification, and to provide a light emission control device for an auto strobe that has a large amount of light and short-distance over dimming characteristics comparable to that of a small strobe.

In each of the above embodiments, a light emission control device equipped with two flash discharge tubes was explained as an example, but the present invention can also be applied to a light emission control device equipped with three or more flash discharge tubes. It goes without saying that similar actions and effects can be obtained.

[Brief explanation of the drawing]

Figure 1 is a graph comparing the dimming characteristics when two flash discharge tubes fire simultaneously and the dimming characteristics when one flash discharge tube fires simultaneously. Figure 2 is a graph showing the dimming characteristics when two flash discharge tubes fire simultaneously. FIG. 3 is a graph showing a comparison of the exposure characteristics in the case of light emission and the exposure characteristics in the case of single light emission; FIG. The figure is a graph comparing the light emission characteristics when two flash discharge tubes fire simultaneously and the light emission characteristics when two flash discharge tubes fire at intervals.
FIG. 6 is an electric circuit diagram of an auto strobe light emission control device showing another embodiment of the present invention, and FIG. 7 is an electric circuit diagram of an auto strobe light emission control device showing another embodiment of the present invention. FIG. 8 is an electric circuit diagram showing a more detailed example of the delayed ignition signal generation circuit shown in FIG. 6, and FIG. FIG. 3 is an electrical circuit diagram illustrating an example. _C1 ...First main capacitor, C1...Dimmer circuit, _C6 ...Integrator capacitor, _C7 ...Second main capacitor, D1...Bistable multivibrator, D2...Oscillation circuit, D3... …counter,
D4...delay circuit, D5...AND circuit (delayed ignition prevention means), E1...delayed ignition signal generation circuit,
F2...AND circuit (delayed ignition prevention means) F3,
F8...Bistable multivibrator, F4...Oscillation circuit, F5...Counter, F6...Delay circuit,
Q ₆ ...transistor (delayed ignition prevention means),
SCR ₄ ... Ignition thyristor, SW ₁ ... Synchro contact, X ₁ ... First flash discharge tube, X ₂ ... Second flash discharge tube.

Claims (1)

[Scope of Claims] 1: a plurality of flash discharge tubes; a dimmer circuit having a photometric circuit that simultaneously stops the light emission of the plurality of flash discharge tubes; and some of the plurality of flash discharge tubes. A first light emission starting circuit that starts the light emission of the flash discharge tube; From the light emission starting operation of this first light emission starting circuit,
a delayed signal generation circuit that outputs a signal after a predetermined time has elapsed; a second light emission start circuit that starts light emission of other flash discharge tubes among the plurality of flash discharge tubes according to the output of the delayed signal generation circuit; A light emission control device for an auto strobe, comprising: blocking means for disabling the signal output of the delay signal generation circuit by the light emission stopping operation of the light control circuit.