JPS59214831A - Strobe device - Google Patents

Abstract

PURPOSE:To reset securely the thyristor in a multiple flash device to the off state as lighting operation is carried out by providing a bypassing switch element which turns on with the output of a lighting operation detecting circuit and allow a current to bypass the circuit between synchro terminals. CONSTITUTION:When a flash discharge bulb 4 emits light, the capacitor 11 of the lighting detecting circuit 10 is discharged through the flash discharge bulb 4, a low-voltage power source 1, and resistances 14 and 13 to turn on a transistor (TR) 12, generating a voltage drop across resistances 15 and 16 as an output. The TR17 as the bypass switch element turns on and the current flowing through a diode 19 and synchro terminals 18 so far flows through the collector and emitter, so that the current supplied to the thyristor 27 in the multiple flash device 25 connected between the synchro terminals 18 is ceased. Consequently, such a trouble point that the thyristor in the multiple flash device stays on and can not turn off like a multiple flash device stays on and can not turn off like a conventional device is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a strobe device that is useful as an artificial light source during photography, and particularly when used with a multi-flash device that has a built-in thyristor as a switching element. This invention relates to a strobe device that is effective for.

Conventional Structure and Problems It is well known that a conventional system strobe device can be used as a multi-flash strobe device by combining it with a multi-flash unit.

In this case, the flash unit that causes the strobe device to emit light in synchronization with the main strobe device provided on the camera side is usually equipped with a high-sensitivity switching element to short-circuit the synchronization terminals of the trigger circuit.

A high voltage thyristor is used for its anode.

The cathodes are directly connected between the synchro terminals.

As is well known, the syscro terminals are connected in parallel with the main capacitor or low-voltage power supply, so when they are short-circuited to emit light, the current flowing between them is:
It will be changed depending on the state of the power supply and the like.

Therefore, in the case of a so-called series type auto strobe device that has a switch element for light emission control in series with a flash discharge tube that emits light by consuming the charge in the main capacitor, when using a multi-flash unit, the thyristor in the multi-flash unit is Great attention must be paid to the holding current.

In other words, in the case of a series type strobe device, since it is possible to emit light with an extremely small amount of light, the voltage of the power supply, etc. mentioned above does not vary greatly, and therefore the value of the current flowing between the synchronization terminals becomes large. In the case of a multi-light unit that uses a thyristor with a small holding current, once the thyristor is made conductive, it cannot be returned to a non-conductive state, making the next light emission operation impossible. There is a risk that this will cause a flash to occur, and great care must be taken to determine the holding current of the multi-flash unit used.

A strobe device that takes the above-mentioned problems into consideration is a strobe device proposed by the applicant of the present invention in Japanese Patent Application No. 31852/1983.

To put it simply, the strobe device proposed above detects a short circuit between the synchro terminals by detecting the fluctuation in the charging voltage of a capacitor that is connected in parallel between the synchro terminals and is charged by the power supply section including the main capacitor. By operating a switch circuit that bypasses the current flowing between the synchro terminals by the detection signal,
This is a device that allows the thyristor of a multi-lamp unit to have a state in which no current is supplied for a while after it becomes conductive once, and reliably returns the thyristor to a non-conductive state.

However, since the above device constitutes an operating system based on the short-circuit operation itself between the synchronizing terminals, it is necessary to conduct various studies on the charging and discharging characteristics of the capacitor based on energy utilization efficiency, operation timing of the switch circuit, etc. Furthermore, in order to obtain a useful device, the configuration of the control system to prevent the Nubuchi circuit from operating in a steady state where power is supplied but no strobe device is used is necessary, and the overall configuration of the device is complicated. and the cost was high, making it not very suitable for practical use.

OBJECTS OF THE INVENTION The purpose of the present invention is to take into account the above-mentioned problems and to provide a series-type auto strobe device with a simple structure that ensures conduction and non-conduction operations regardless of the number of flash units used. The idea is to provide it at a low price.

Composition of the Invention In order to achieve the above-mentioned object, the strobe device according to the present invention includes a light emission detection circuit that detects the light emission operation of a flash discharge tube that consumes charging energy of a main capacitor to emit light;
The light emission detection circuit is configured to include a bypass switch element that is made conductive when detecting light emission from the discharge tube and bypasses a current that is about to flow between the synchronization terminals.

DESCRIPTION OF EMBODIMENTS FIG. 1 is an electric circuit diagram showing an embodiment of a strobe device according to the present invention.
A well-known DC-DC converter circuit that boosts the voltage of 3
4 is a main capacitor, 4 is a flash discharge tube, 6 is a main switch element that controls the light emission operation of the flash discharge tube 4, 6 is a trigger circuit consisting of a trigger capacitor, a trigger transformer, etc., 7
8 is a commutation circuit that controls the operation of the main switch element; 9 is a thyristor that is a switching element that controls the operation of the trigger circuit 6; 9 is a commutation circuit that controls the operation timing of the commutation circuit 8 based on reflected light from the subject or an arbitrary set time; Each control circuit is shown.

In addition, in the figure, 10 surrounded by a broken line is a capacitor 11, a transistor 12 which is a switch element, and a resistor 13°14.15.
．． 16 shows a light emitting operation detection circuit for detecting the light emitting operation of the flash discharge tube 4.

17 is a transistor which is a bypass switching element which bypasses the current flowing into the synchronization terminal 18 by being turned on and controlled by the output of the light emitting operation detection circuit 1o; 18 is a synchronization terminal; and 19 is a diode. ,
Reference numerals 20 and 21 indicate resistors for making the transistor 22 conductive when the synchro terminal 18 is short-circuited, and 23 and 24 indicate resistors for the gate of the thyristor T, respectively. Incidentally, the device 25 surrounded by a dashed-dotted line is a light multiplying device which includes a light receiving sensor 26 and a cylisk 2, and is connected to the synchro terminal 18 as shown by the broken line.

Hereinafter, the operation of an embodiment of the strobe device according to the present invention having the above-described structure will be described when the strobe device is connected as shown by the broken line to the multi-flash unit 25 enclosed by the dashed-dotted line and used for multi-flash lighting.

Now, in the light emission ready state where the main capacitor 3 etc. are charged with the high voltage obtained by boosting the voltage of the low voltage power supply 1 by the DC-DC converter circuit 2, the light receiving unit 25 connected between the synchronizing terminals 18 receives light. Suppose that the sensor 26 receives the light emitted from the main neutral device on the camera side, and the electromotive force generated in the light receiving sensor 26 supplies the gate voltage of the thyristor 2T. Since the voltage is supplied through 19, conduction is established.

The fact that the thyristor 27 is made conductive means that a current flows through the resistors 20 and 21, the diode 19, and the thyristor 2. Therefore, at this time, the voltage drop across the resistor 2 due to the current causes Transistor 22 will be rendered conductive.

When transistor 22 is rendered conductive, resistor 23 .
Current flows from the power source 1 through the resistor 24, and the thyristor 7 is also brought into conduction by the voltage drop across the resistor 24, causing the trigger circuit 6 that triggers the flash discharge tube 4 and the main switch element 5 to operate. Then, the flash discharge tube 4 emits light.

When the flash discharge tube 4 emits light, the charge in the capacitor 11 of the light emission operation detection circuit 10 is transferred to the flash discharge tube 4, the low voltage power supply 1,
It will be discharged through resistor 14.13, and resistor 1
The voltage drop of 4 causes the transistor 12 to conduct, and as a result, current flows through the resistor 15 and 16 in the loop of the power supply 1 and the transistor 12. That is, the light emitting operation detection circuit 10 detects the resistance 1 when the flash discharge tube 40 emits light.
5.16 will generate a voltage drop as an output.

By the way, as is clear from the drawing, the voltage drop that is the output of the light emitting operation detection circuit 1o is the voltage generated across the resistor 16 of the transistor 1, which is a bypass switching element.
Since it will be supplied between the base and emitter of 7,
This makes the transistor 17 conductive. Since the transistor 17 is connected to the power supply 1 through the resistor 20, 21, the current that previously flowed through the diode 19 and the synchro terminal 18 now flows between the collector and the emitter.
7 is in a conductive state, and as a result, the current supplied to the cyrisk 27 connected between the synchronizing terminals 18 disappears. That is, it will be bypassed by transistor 17.

It goes without saying that when the current supplied to the thyristor 27 disappears, the thyristor 27 returns to a non-conducting state regardless of the holding current. Even if a similar type is used, there will be no problem such as the thyristor in the multiplexer maintaining conduction and being unable to return to the non-conduction state as in conventional devices.

Note that while the transistor 17 is in a conductive state, the transistor 22 remains conductive, and the gate voltage continues to be supplied to the thyristor 14, so that the trigger circuit 6 is in an operating state, but when the flash discharge tube 4 finishes emitting light. Since the output of the light emitting operation detection circuit 10 disappears due to the non-conduction of the transistor 12 and the transistor 17 is made non-conductive, the transistor 22 returns to the non-conductive state at the end of the light emission, and the thyristor 14 is activated without any problem. This means that the trigger circuit 6 can return to a non-conductive state and the trigger circuit 6 can also return to a non-operating state.

FIG. 2 is an electric circuit diagram showing another embodiment of the strobe device according to the present invention, and the same numbers as those in FIG. 1 have the same functions.

In FIG. 2, the number 28 indicates a power supply circuit between the synchronizing terminals 18, which is composed of a series body of a resistor 29 and a power supply capacitor 3o connected in parallel with the low voltage power supply 1, and 31 indicates a diode.

In the circuit as shown in the figure, when the light emitted from the main Nutrobo device on the camera side enters the light receiving sensor 26 of the multiplexer 25 connected to the synchronization terminal 18 as in the previous embodiment, the thyristor 27 is activated by the light receiving sensor 26. In this embodiment, this thyristor 2 is supplied with a gate voltage.
7 anode.

Since the cathode is connected in parallel with the power supply capacitor 3° of the power supply circuit 28, in the above case, the charging charge of the power supply capacitor 30 is supplied via the diode 31, and the above-mentioned risk 27 is extremely simple. is made conductive.

When the thyristor 27 of the multiple light unit 26 is brought into conduction,
As explained in the previous embodiment, the current flowing through the resistor 20.21 causes the citrate 22 to become conductive;
The thyristor 14 is then brought into conduction, the trigger circuit 6 is operated, and the flash discharge tube 4 is connected to the main capacitor 3.
It will emit light by consuming the charged charge.

Then, when the flash discharge tube 4 emits light, the light emitting operation detection circuit 1o operates, and the transistor 17 is made conductive.

In the case of the embodiment shown in FIG. 2, the transistor 17 is connected to both ends of the power supply capacitor 3o of the power supply circuit 28, and when the base voltage is supplied by the operation of the light emitting operation detection circuit 10 as described above. It will be in a conductive state.

When the l-run risk 17 is brought into conduction, the capacitor 7' sensor 3o, which has been supplied to the synchro terminal 18 and has been working as a conduction power source for the thyristor 27 of the multiplexer 25, is turned on.
No charge! Charge will be discharged through this transistor 17.

When the charge in the power supply capacitor 3o is discharged by conduction of the transistor 17, a current tries to flow between the synchronization terminals 18 through the power supply 1, the resistors 22 and 23, and the diode 19. The current value flowing through the loop is increased by increasing the resistance value of the resistor 22.230 and the power supply circuit 28.
By appropriately setting the resistance value of the resistor 29, the minimum value of the holding current value of the various thyristors used in various lighting multipliers can be set to be sufficiently small. At the same time as the discharge of the charge in the power supply capacitor 30, the thyristor 27 of the multiple light unit 25 becomes non-conductive.

That is, as in the previous embodiment, if the light emission operation is performed, the cyrisk 27 of the multi-lamp unit 26 connected between the synchro terminals 18 will always return to the non-conductive state.

The embodiment shown in Fig. 1 directly supplies the energy necessary for the conduction of the SI risks of the multiple lamps through the power supply and the resistor. In contrast, in the embodiment shown in Fig. 2, the conduction characteristics of the thyristor are set in consideration of the thyristor's conduction characteristics. Needless to say, since the power source is the charge of the capacitor, it is only necessary to set the capacitance of the capacitor appropriately.

Effects of the Invention The strobe device according to the present invention includes a light emitting operation inspection circuit that detects the light emitting operation of the flash discharge tube and generates a predetermined output voltage;
By having a simple configuration of a shunting switch element that becomes conductive when supplied with the above output voltage and shunts the current that is about to flow between the synchro terminals, it can be combined with a multi-light unit with a built-in thyristor. When used as a strobe device for multiple flash units, it has the effect of reliably returning the cyrisk in the multiple flash unit to a non-conductive state as light is emitted regardless of the type of multiple flash unit used.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram showing one embodiment of the strobe device according to the present invention, and FIG. 2 is an electric circuit diagram showing another embodiment of the strobe device according to the present invention. 1...Low voltage power supply, 2...DC-DC converter circuit, 3...Main capacitor, 4...
... Flash discharge tube, 5 ... Main switch element, 6
・River: Trigger circuit, 8: Commutation circuit, 9:
...control circuit, 1o river...light emission operation detection circuit,
17... Bypass switch element, 18...
Terminal for synchro, 25... Multi-lighter, 27... Mark/Sirisk, 28... Power supply circuit.

Claims (4)

[Claims] (1) It has a synchronization terminal that drives a trigger circuit that excites a flash discharge tube that emits light by consuming the charging voltage of a main capacitor that is charged by a DC-DC converter circuit that boosts the voltage of a low-voltage power supply, and the flash flash In a serial control Nutrobo device that is connected in series with a discharge tube and is equipped with a main switch element that controls the amount of light emitted by the flash discharge tube and an operation control system for this main switch element, the light emission operation of the flash discharge tube is detected and a predetermined control is performed. a light emitting operation detection circuit that generates an output signal at a predetermined output terminal, and a bypass switch element whose main pole is connected in parallel with the synchro terminal and whose control pole is connected to the output terminal, A strobe device characterized in that when the current is supplied to the control pole, the bypass switch element is made conductive, thereby bypassing the current that is about to flow into the synchronization terminal. (2) The light emitting operation detection circuit includes a first series body of a first resistor group and a capacitor connected in parallel via a main capacitor and the low voltage power supply, and a second series body connected to both ends of the low voltage power supply. It consists of a second series body of a resistor group and a control switch element, one end of the second resistor group is connected to the control pole of the bypass switch element, and when the flash discharge tube emits light, the capacitor discharges the 2. The strobe device according to claim 1, wherein the control switch element is made conductive and the voltage of the low-voltage power supply is supplied to the control pole via one end of the second resistor group. (3) It has a synchronization terminal that drives a trigger circuit that excites a flash discharge tube that emits light by consuming the charge of the main capacitor that is charged by the DC-DC converter circuit that boosts the voltage of the low-voltage power supply, and the flash discharge A series control strobe device comprising a main switch element connected in series with the tube to control the amount of light emitted by the tube and an operation control system for the main switch element, the strobe device having a power supply capacitor connected in parallel with the synchro terminal; a power supply circuit that supplies a predetermined voltage to the synchronizing terminal; a light emitting operation detection circuit that detects the light emitting operation of the flash discharge tube and generates a predetermined output signal to the predetermined output terminal; and a bypass switch element to which a main pole is connected and a control pole is connected to the output terminal, and when the output signal is supplied to the control pole, the bypass switch element is made conductive and a predetermined state of the power supply circuit is set. A strobe device characterized in that a current that attempts to flow through the synchronization terminal is bypassed by a voltage. (4) The light emitting operation detection circuit includes a first series body of a first resistor group and a capacitor connected in parallel via a main capacitor and the low voltage power supply, and a second series body connected to both ends of the low voltage power supply. a second series body of a resistor group and a control switch element, one end of the second resistor group is connected to a control pole of the bypass switch element, and when the flash discharge tube emits light, the capacitor discharges. 4. The strobe device according to claim 3, wherein the control switch element is made conductive and the voltage of the low voltage power source is supplied to the control pole via one end of the second resistor group.