JPS6327822A - Strobe device - Google Patents

Abstract

PURPOSE:To preclude the adverse influence of a leak current from a transistor (TR) by providing a switch element whose operation is controlled in synchronism with a TR connected in series with a flash discharge tube between a double voltage capacitor and the TR. CONSTITUTION:A diode 10 and the TR 21 are connected in series with the flash discharge tube 17 and further the series body of the double voltage capacitor 6 and a switch element 22 is connected in parallel to the diode 10. Then, the light emission of the flash discharge tube 17 is controlled through the operation of the TR 21. Consequently, a commutating capacitor which has capacity to some extent and the limitation of the shortening of a charging time is eliminated and a rise in the terminal potential across the flash discharge tube 17 by the double voltage capacitor can be expected by the switch element 22 without being affected by the leak current of the TR 21.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a strobe device, and more particularly to a strobe device in which a transistor is connected in series with a flash discharge tube, and the potential across the flash discharge tube is approximately twice the charging voltage of a main capacitor. This invention relates to a type of strobe device that can be lifted up.

2. Description of the Related Art Conventionally, a strobe device of the type that makes it easier to emit light by increasing the potential across the open discharge tube during light emission operation to be higher than the charging voltage of the main capacitor is known, for example, as disclosed in Japanese Patent Application Laid-Open No. 67-38426. Various types are known.

FIG. 3 shows an electric circuit diagram of the strobe device disclosed in the above-mentioned Japanese Patent Laid-Open No. 57-38426, and its operation will be briefly explained below.

Now, when the power switch 1 is closed, the DC-DC converter circuit 2 receives the power supply E and starts operating, and as is well known, the main capacitor 3. Trigger capacitor 4. The commutating capacitor 5 is charged. At the same time, the voltage doubler capacitor 6 is charged with resistors 7, 8, and so on, as shown in the polarity shown. diode 9
This will be done through etc. In addition, diode 1o
Needless to say, is provided for charging the voltage doubler capacitor 6 to the illustrated polarity.

When the charging of each of the capacitors progresses and the charging voltage of the commutation capacitor 6 reaches a predetermined value, the neon tube 11 lights up to indicate the completion of charging, and the capacitor 12- is charged. Note that the charging voltage of this capacitor 11 is controlled to a predetermined value by a Zener diode 13 or the like.

When the synchro contact 14 is closed in this state, the charge of the capacitor 12 is supplied to the gate of 5CR1s,
This 5CR15 is conductive.

When 5CR15 becomes conductive, the charge in the trigger capacitor 4 is discharged through the primary winding 16a of the trigger transformer 16, and the flash discharge tube 17 is triggered by the high voltage generated in the secondary winding 16b.

Further, when 5CR15 becomes conductive, the charging voltage of the voltage doubler capacitor e is superimposed on the charging voltage of the main capacitor 3 and is applied to the flash discharge tube 17 via the 5CR15.

Therefore, it is extremely easy to start the flash discharge tube 17 to emit light, and the flash discharge tube 17 is easily excited and immediately starts emitting light by consuming the charge in the main capacitor 3, thereby illuminating a subject (not shown). Ru.

At this time, it goes without saying that the charging voltage of the voltage doubler capacitor 10 is approximately equal to that of the main capacitor 3.
It is also clear that the charging voltage needs to be applied to the flash discharge tube 17 only at the initial stage of light emission, and that it can be constructed using a small-capacity capacitor.

When the reflected light from the subject reaches a predetermined amount, the sensor 18 supplies a gate signal to the 5CR 19, making the 5CR 19 conductive.

When 5CR19 becomes conductive, the charge charged in the commutation capacitor 6 is released, and 5CR15 becomes reverse biased.
5CR15 is inverted in the non-conducting state, and therefore flash discharge tube 1
7 will stop emitting light.

The operations described above are a series of operations of the conventional device shown in FIG.

Problems to be Solved by the Invention Needless to say, the conventional device shown in FIG.
becomes easier to emit light.

However, when looking at the charging operation of the voltage doubler capacitor 6 for the next light emitting operation, needless to say in detail, since the commutating capacitor 6 is included, a certain amount of time is required.

That is, the charging operation of the voltage doubler capacitor 60 for the next light emitting operation is performed after the SC'R 15 is turned off and in synchronization with the charging of the commutating capacitor 6, and therefore, the charging time constant of the commutating capacitor 5 is To be more specific, the commutation capacitor 6 uses a capacitor with a somewhat large capacitance, for example, a capacitor with a capacitance about 10 times larger than the voltage doubler capacitor 6, in order to reliably reverse bias the 5CR1s. In addition, the voltage doubler capacitor 6 is connected in parallel with the commutating capacitor 3, and only when the charging of the commutating capacitor 6 reaches a predetermined value, the voltage doubler capacitor 6 also reaches the predetermined value required for the next light emission operation. It will be charged.

Therefore, when it is desired to repeat the light emitting operation of the flash discharge tube 17 at a high speed in a short period of time, such as when the flash discharge tube 17 performs the light emitting operation following the camera's motor drive device, there is a limit to the repetition frequency. It goes without saying that this limit occurs regardless of the presence or absence of the voltage doubler capacitor 6.

In other words, the next light emitting operation cannot be performed until the commutation capacitor 5 is completely charged.

On the other hand, it is clear that the commutating capacitor 6 can be eliminated in order to solve the above-mentioned problem, and although it will not be explained heretofore, it is possible to replace the thyristor 16 as a switching element connected in series with the flash discharge tube 17. Various types of devices using transistors are known (Utility Model Publication No. 43-2134).
Publication No. 4, etc.).

However, in the circuit shown in FIG. 3, if the thyristor 16 is simply replaced with a transistor, the following new problems will arise.

That is, a transistor inevitably has a leakage current between its collector and emitter, which has the problem that the voltage doubler capacitor 6 cannot be sufficiently charged, and is also undesirable from the point of view of effective use of energy.

The present invention has been made in consideration of the above points, and provides a strobe device in which a transistor is connected in series with a flash discharge tube that does not require a commutating capacitor, which can emit light repeatedly at high speed, and which can also be expected to have the effect of a voltage doubler capacitor. The purpose is to provide.

Means for Solving the Problems A strobe device according to the present invention comprises a DC high voltage power supply, a main capacitor charged by the DC high voltage power supply, and a flash discharge tube connected to both ends of the main capacitor.

A first series body consisting of a first die, a transistor, a voltage doubler capacitor connected to both ends of the diode, a second series body consisting of a switch element having a control pole, and the voltage doubler capacitor are charged. a charging means for charging the flash discharge tube so that a voltage is supplied to the flash discharge tube through the switch element, the transistor, and the main capacitor; and a trigger circuit that triggers the flash discharge tube through the switch element and the transistor; It is comprised of a control means for controlling the operation of the above-mentioned switch element and the transistor in synchronization.

Function: As described above, the strobe device according to the present invention is provided with a switch element between the voltage doubler capacitor and the transistor connected in series with the flash discharge tube, the operation of which is controlled in synchronization with the transistor. As long as the switch element is not turned on, the charged energy of the voltage doubler capacitor will not be released, and in other words, the adverse effects of the leakage current of the transistor are completely prevented.

Embodiment FIG. 1 is an electrical circuit diagram showing an embodiment of a strobe device according to the present invention. In the figure, the same reference numerals as in FIG. 3 indicate the same functional members.

In the figure, 20 is a well-known DC-DC converter circuit or the like, and is a DC high-voltage power supply for charging the main controller 3; 21 is a flash discharge tube 17 connected in series with a diode 10; The transistors form one series body, and this first series body is connected to both ends of the main capacitor 3 as shown.

Reference numeral 22 denotes a thyristor, which is a switching element equipped with a control pole that is connected in series with the voltage doubler capacitor 6 to form a second series body, and as shown, this second series body is connected to both ends of the diode 1o. It is connected.

23 is a charging means for charging the voltage doubler capacitor e according to the illustrated polarity; in this embodiment, one end is connected to the high potential end of the main capacitor 3 and the other end is connected to the connection point between the voltage doubler capacitor 6 and the thyristor 22; The second resistor 26 has one end connected to the connection point between the voltage doubler capacitor 6 and the diode 10, and the other end connected to the low potential end of the main capacitor 3.

26 is a trigger circuit, which consists of a trigger capacitor 27° and a trigger transformer 28, and when the above-mentioned thyristor 22 and transistor 210 are turned on, the trigger transformer 28 is
The charging current that charges the trigger capacitor 27 through the primary winding 28a generates a high voltage in the secondary winding 28b, which triggers the flash discharge tube 17.

29 is the above-mentioned transistor 21. A control means for controlling the operation of the thyristor 22 in synchronization with the synchro switch 3.
an on-signal generation circuit 30 that detects the closing of the transistor 21 and outputs an on-signal for the transistor 21 and the like; For example, flash discharge tube 1
The above-mentioned turning on is performed by detecting that the amount of light received by the light receiving sensor 33 that receives reflected light from a subject (not shown) based on the light emission of step 7 has reached a predetermined value, or by detecting an arbitrarily set predetermined period. A dimming circuit 32 that cuts off the signal and a transistor 21. It is composed of transmission circuits 34 and 35 that transmit signals to the thyristors 22, respectively.

The operation of one embodiment of the strobe device according to the present invention having the above-described configuration will be described below.

Now, when the DC high voltage power supply 2o is activated and a DC high voltage is output, the main capacitor 3 is charged and at the same time, the voltage doubler capacitor 6 is connected to the resistor 24, 25 which constitutes the charging means 23.
charged to the polarity shown.

When the synchro contact 31 is closed with the main capacitor 3 etc. fully charged, the ON signal generation circuit 30 activates the transistor 21. An on signal for turning on the thyristor 22 is generated, and the on signal is transmitted to the base of the transistor 21 and the control pole of the thyristor 22 via transmission circuits 34 and 35, respectively.

The transistor 21 and the thyristor 22 try to turn on at the same time due to the supply of the on signal, but in detail, when the transistor 21 is sufficiently turned on, the thyristor 22 turns on.

Transistor 21. When the thyristor 22 is turned on, the charge of the voltage doubler capacitor 6 with the illustrated polarity is transferred to the thyristor 22. Transistor 21. The voltage is applied to the flash discharge tube 17 via the main capacitor 3, and at the same time the potential across the terminals is raised, the trigger capacitor 27 is applied to the trigger transformer 2.
8 primary winding 28a, thyristor 221 transistor 2
It will be charged by the current flowing through 1. Needless to say, the charging current that charges the trigger capacitor 27 at this time is the secondary winding 2a of the trigger transformer 28.
bK high voltage will be generated, and the flash discharge tube 17 will be triggered.

That is, trigger circuit 26 in the illustrated embodiment includes transistors 21 . The charging operation of the trigger capacitor 27 via the thyristor 22 triggers the flash discharge tube 1.

By the trigger operation as described above, the flash discharge tube 17 consumes the charge in the main capacitor 3 and emits light.

Here, assuming that the light control circuit 32 is in a state where the operation is controlled by the light receiving sensor 33, when the amount of light received by the light receiving sensor 33 due to the light reflected from the subject based on the light emission reaches a predetermined value, the light control circuit 32 32 operates to cut off the on signal that had been output from the on signal generating circuit 30 until then.

When the ON signal is cut off, the transistor 21 becomes OFF, and therefore the thyristor 22 also becomes OFF, the flash discharge tube 17 stops emitting light, and the illustrated circuit starts charging the main capacitor 3 etc. by the DC high voltage power supply 20. It will return to its initial state. It goes without saying that at this time, the charge in the trigger capacitor 27 of the trigger circuit 26 is instantaneously discharged via the resistor 24 and the like, and is prepared for the next trigger operation.

The operation described above is the main operation of the embodiment shown in FIG. 1, and it goes without saying that the commutating capacitor 6 used in the conventional device shown in FIG. 3 is used for this operation. do not need. As a result, the frequency of repeated light emission of the flash discharge tube 17 is affected by the discharge time constant of the trigger capacitor 27 described above. Specifically, by decreasing the resistance value of the resistor 24, the discharge time constant can be adjusted. In other words, in the embodiment shown in FIG. 1, by appropriately adjusting the operations of the on-signal generating circuit 3o and the dimming circuit 32, it is possible to repeatedly emit light for several tens of milliseconds. It will become a reality. It should be noted that, at this time, if the charge in the main capacitor 3 is largely consumed, the flash discharge tube 17 may not be able to emit light even when triggered, although the potential at both ends of the flash discharge tube 17 is raised by the voltage doubler capacitor 6. Needless to say, in order to achieve the above-mentioned repeated high-frequency light emission, it is necessary to appropriately control the amount of charging energy used by the main capacitor 3 in one light emission operation by controlling the operation of the dimming circuit 32. Nor.

In addition, the thyristor 22 does not turn on until the transistor 21 reaches a sufficiently on state, so even if leakage current occurs between the collector and emitter of the transistor 21, the effect on charging of the voltage doubler capacitor 6 is that the thyristor 22 It will be shut off at , and it will disappear completely.

Furthermore, in the embodiment shown in FIG. 1, the triggering operation of the flash discharge tube 17 is performed by the charging operation of the trigger capacitor 27 as described above, but for example, as shown in FIG. 22, the primary winding 28a of the trigger transformer 28 and the trigger capacitor 27 are connected to form a trigger circuit 27. and charges the transistor 21. When the thyristor 23 is turned on, the charged charge is released through these elements and the primary winding 28a of the trigger transformer 28, and the secondary winding 2
Needless to say, it is also possible to generate a high voltage at 8b and trigger the flash discharge tube 17 with this high voltage.

Effects of the Invention As described above, the strobe device according to the present invention connects a diode and a transistor in series with the flash discharge tube, further connects a series body consisting of a voltage doubler capacitor and a switching element in parallel to the diode, and connects the transistor in parallel. Since the light emission of the flash discharge tube is controlled by the operation, it is possible to eliminate the commutating capacitor which has a certain amount of capacity and has a limit in shortening the charging time, and the above-mentioned switch element reduces the influence of the leakage current of the above-mentioned transistor. This has the effect that it is possible to expect the voltage doubler capacitor to increase the potential at both ends of the flash discharge tube without causing any damage.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram showing one embodiment of the strobe device according to the present invention, FIG. 2 is a main part electric circuit diagram showing another example of the trigger circuit 26 in FIG. 1, and FIG. 3 is a voltage doubler capacitor. 1 shows an electrical circuit diagram of a conventional strobe device equipped with a conventional strobe device. 3... Main capacitor, 6... Voltage doubler capacitor, 1o... Diode, 17...
・・Flash discharge tube, 2゜・・・・DC high voltage power supply, 21
...Transistor, 22...Thyristor (switch element), 23...Charging means, 24
．． 25...Resistor, 26...Trigger circuit, 27...Trigger capacitor, 28...
...Trigger transformer, 29...Control means,
30...On signal generation circuit, 31...
Synchro switch, 32...Dimmer circuit, 33.
...Light receiving sensor, 34, 35...Transmission circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure? 0

Claims (4)

[Claims] (1) A DC high-voltage power supply, a main capacitor charged by the DC high-voltage power supply, a first series body consisting of a flash discharge tube, a diode, and a transistor connected to both ends of the main capacitor, and a first series body connected to both ends of the diode. a second series body consisting of a voltage doubler capacitor connected thereto and a switch element having a control pole, and the voltage doubler capacitor oriented such that its charging voltage can be supplied to the flash discharge tube via the switch element, the transistor and the main capacitor. a trigger circuit for triggering the flash discharge tube via the switch element and the transistor; and a control means for synchronously controlling the operations of the switch element and the transistor. . (2) The control means includes an on-signal generating circuit that operates to supply an on-signal to the control pole of the switch element and the base of the transistor, and an on-signal generation circuit that operates to cut off the supply of the on-signal to the control pole and the base of the transistor. A strobe device according to claim (1), comprising a dimming circuit. (3) The strobe according to claim (1), wherein the trigger circuit has a series body consisting of a trigger capacitor and a primary winding of a trigger transformer connected to both ends of a main capacitor via a switch element and a transistor. Device. (4) The strobe device according to claim (1), wherein the trigger circuit has a series body consisting of a trigger capacitor and a primary winding of a trigger transformer connected to both ends of a series body consisting of a switch element and a transistor. .