JPH1069996A - Stroboscopic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exhibit a function of a protective circuit and carry out protective operation even in the case mutual interference of capacitors is prevented by using a diode. SOLUTION: High voltage HV is supplied to a supply terminal 1. A high voltage HV from a supply terminal 1 is applied to plus terminals of main capacitors 3a, 3b, 3c, 3d through respective diodes 2a, 2b, 2c, 2d. The plus terminals of the main capacitors 3a, 3b, 3c, 3d are mutually connected through respective diodes 4a, 4b, 4c, 4d for mutual interference prevention, and these connection middle points are connected with one end of a xenon discharge lamp 7a through, for example, a switching element (IGBT) 5a and a resistor 6a. Further, the other end of the xenon discharge lamp 7a is connected with one end of a protective circuit constituted of parallel circuits of coils 8a and diodes 9a and the other end of the protective circuit is connected with minus terminals of the commonly connected main capacitors 3a, 3b, 3c, 3d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flash device using, for example, an IGBT as a switching element.

[0002]

2. Description of the Related Art As a strobe device using an IGBT as a switching element, for example, a device as shown in FIG. 3 has been conventionally proposed. That is, for example, in the configuration of FIG. 3, the high voltage HV from the high voltage generating means (not shown) is applied to the + terminal of the main capacitor 32 through the terminal 31.

The + terminal of the main capacitor 32 is connected to one end of a protection circuit composed of a parallel circuit of a coil 33 and a diode 34, and the other end of the protection circuit is connected through a switching element (IGBT) 35 and a variable resistor 36. It is connected to one end of a xenon discharge tube 37. Further, the other end of the xenon discharge tube 37 is connected to the negative terminal of the main condenser 32.

Here, the protection circuit for the coil 33 and the diode 34 has a function of suppressing high-frequency oscillation of the current flowing through the connected circuit. This prevents, for example, an inrush current when the power is turned on, or protects the switching element (IGBT) 35 and the xenon discharge tube 37 by suppressing a rapid change in current.

[0005] A set signal terminal 38 is connected to a set input of a driver circuit 39 of the switching element (IGBT) 35. Further, the slider of the variable resistor 36 is connected to the base of a detecting transistor 42 through an integrating circuit including a resistor 40 and a capacitor 41, and the output terminal of the transistor 42 is connected to the reset input of the driver circuit 39. .

Further, a trigger signal terminal 43 is connected to a control terminal of a thyristor 46 via a capacitor 44 and a resistor 45. One end of the current path of the thyristor 46 is connected through a resistor 47 to, for example, one end of a xenon discharge tube 37. The other end of the current path of the thyristor 46 is connected to the other end of the xenon discharge tube 37.

[0007] One end of a current path of the thyristor 46 is connected to one end of a primary coil of a transformer 49 through a capacitor 48. Furthermore, this transformer 49
One end of the next coil is connected to the trigger electrode of the xenon discharge tube 37. The other end of each coil of the transformer 49 is connected to the other end of the xenon discharge tube 37.

Therefore, in this device, when the set signal is supplied to the terminal 38, the driver circuit 39 is driven and the switching element (IGBT) 35 is turned on. When a trigger signal is supplied to the terminal 43, an instantaneous voltage is applied to the trigger electrode of the xenon discharge tube 37, and the xenon discharge tube 37 starts discharging and emitting light.

Further, when the discharge light emission of the xenon discharge tube 37 is started, a voltage is taken out to the slider of the variable resistor 36. This voltage is applied to the resistor 40 and the capacitor 41
When the integrated output reaches a predetermined value, the transistor 42 is turned on and a reset signal is input to the driver circuit 39.

In this way, the discharge light emission of the xenon discharge tube 37 is controlled. By using a signal taken out from, for example, a shutter contact (not shown) as the above-described trigger signal, the xenon discharge tube 37 discharges and emits light in synchronization with, for example, the driving of the shutter, and so-called strobe light emission is performed.

[0011]

In the above-mentioned circuit, when a plurality of xenon discharge tubes are provided to perform continuous light emission, an extremely large capacity is required for the main capacitor. Therefore, it has been considered to provide a plurality of main capacitors in parallel and prevent mutual interference between these capacitors by using, for example, a diode.

However, when such a diode is used to prevent mutual interference of capacitors,
Due to the influence of the diode, the function of the protection circuit of the coil 33 and the diode 34 was hindered, and the protection operation might not be performed.

This application has been made in view of the above points, and the problem to be solved is that in the conventional device, when a diode is used to prevent mutual interference of capacitors, The function of the protection circuit is hindered by the influence of the diode, and the protection operation may not be performed.

[0014]

According to the present invention, a protection circuit comprising a coil and a diode is provided on the ground side of a xenon discharge tube. According to this, a capacitor is provided by using a diode. Even when mutual interference is prevented, the function of the protection circuit can be exerted and the protection operation can be performed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, in a strobe device comprising a main capacitor, a switching element, a control circuit thereof, and a xenon discharge tube and a trigger circuit, a plurality of main capacitors are respectively connected in parallel via diodes. In addition, a protection circuit including a coil and a diode is provided on the ground side of the xenon discharge tube.

Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an example of a strobe device to which the present invention is applied. In FIG. 1, a high voltage HV from a high voltage generating means (not shown) is supplied to a supply terminal 1. The high voltage HV from the supply terminal 1
Is applied to the + terminals of the main capacitors 3a, 3b, 3c, 3d through the diodes 2a, 2b, 2c, 2d, respectively.

The main condensers 3a, 3b, 3c, 3
The + terminal of d is a diode 4 for preventing mutual interference.
a, 4b, 4c, and 4d, and a connection midpoint is connected to one end of a xenon discharge tube 7a through, for example, a switching element (IGBT) 5a and a resistor 6a.

Further, the other end of the xenon discharge tube 7a is connected to one end of a protection circuit comprising a parallel circuit of a coil 8a and a diode 9a, and the other ends of the protection circuit are commonly connected to main capacitors 3a, 3b, 3c. , 3d.

The set signal terminal 10 is connected to the set input of the driver circuit 11 of the switching element (IGBT) 5a. Further, a differentiating circuit including a capacitor 12 and a resistor 13 is connected between both ends of the resistor 6a, and an integrating circuit including a resistor 14 and a capacitor 15 is connected between both ends of the resistor 13.

A detection transistor 16 is connected between both ends of the capacitor 15, and an output terminal of the transistor 16 is connected to a reset input of the driver circuit 11.

Further, a trigger signal terminal 17 is connected to a control terminal of a thyristor 20 via a capacitor 18 and a resistor 19. One end of the current path of the thyristor 20 is connected through a resistor 21 to, for example, one end of a xenon discharge tube 7a. The other end of the current path of the thyristor 20 is connected to the other end of the xenon discharge tube 7a.

One end of a current path of the thyristor 20 is connected to one end of a primary coil of a transformer 23 through a capacitor 22. Furthermore, this transformer 23
One end of the next coil is connected to the trigger electrode of the xenon discharge tube 7a. The other end of each coil of the transformer 23 is connected to the other end of the xenon discharge tube 7a.

Therefore, in this device, when the set signal is supplied to the terminal 10, the driver circuit 11 is driven to turn on the switching element (IGBT) 5a. When a trigger signal is supplied to the terminal 17, an instantaneous voltage is applied to the trigger electrode of the xenon discharge tube 7a, and the xenon discharge tube 7a starts discharging and emitting light.

Further, when the discharge light emission of the xenon discharge tube 7a is started, a voltage is taken out across the resistor 6a. This voltage is supplied to the integrating circuit of the resistor 14 and the capacitor 15 through the differentiating circuit of the capacitor 12 and the resistor 13. When the integrated output reaches a predetermined value, the transistor 16 turns on and a reset signal is input to the driver circuit 11.

In this way, the discharge light emission of the xenon discharge tube 7a is controlled. By using a signal taken out from, for example, a shutter contact (not shown) as the above-mentioned trigger signal, the xenon discharge tube 7a discharges and emits light in synchronization with, for example, driving of the shutter, so that so-called strobe light emission is performed.

In this case, the protection circuit for the coil 8a and the diode 8a is connected between the other end of the xenon discharge tube 7a and the minus terminals of the main capacitors 3a, 3b, 3c, 3d. Thereby, the function of the protection circuit is not hindered by the diodes 4a, 4b, 4c, and 4d for preventing mutual interference, and a good protection operation is performed.

Therefore, in this device, even when the mutual interference between the capacitors is prevented by using a diode by providing a protection circuit including a coil and a diode on the ground side of the xenon discharge tube, the function of the protection circuit is exhibited. And a protection operation can be performed.

Thus, in the conventional device, when the diode is used to prevent the mutual interference of the capacitors, the function of the protection circuit is hindered by the influence of the diode, and the protection operation may not be performed. According to the present invention, even when the mutual interference of the capacitors is prevented by using the diode, the function of the protection circuit can be exhibited and the protection operation can be performed.

In the above circuit, the switching element (IGBT) 5a, the resistor 6a, the xenon discharge tube 7
a, a driver circuit including a protection circuit for the coil 8a and the diode 9a, a differentiating circuit, an integrating circuit, a trigger circuit, and the like, for example, further include a plurality of circuits (switching element (IGBT) 5b, resistor 6b, xenon The discharge tube 7b, the coil 8b, the diode 9b) and the like can be provided in parallel.

In this way, it is possible to form a device for continuously emitting strobe light from a plurality of xenon discharge tubes 7a, 7b. In this case, a large-capacity circuit in which the main capacitors 3a, 3b, 3c, and 3d are provided in parallel is particularly effective.

Further, in the above-described circuit, a differentiating circuit of the capacitor 12 and the resistor 13 is connected to the resistor 6a provided between the switching element (IGBT) 5a and the xenon discharge tube 7a, so that the xenon discharge tube 7
The waveform of the current flowing through a is differentiated, for example, as shown by the solid line in FIG.

That is, this current waveform is similar to, for example, the light emission characteristics of the xenon discharge tube 7a shown by a broken line in the figure, thereby preventing unnecessary power consumption. Therefore, in this circuit, since there is no waste in power consumption, it is possible to reduce the number of times of light emission in the case of battery driving and to eliminate the risk of unnecessary heat generation.

Further, by integrating a voltage corresponding to a current waveform approximate to the light emission characteristic and obtaining a reset signal of the driver circuit 11, the light emission characteristic and the timing of the reset signal can be accurately matched. .

According to the above-described strobe device, in the strobe device including the main capacitor, the switching element, the control circuit thereof, and the xenon discharge tube and the trigger circuit, a plurality of main capacitors are connected in parallel via the respective diodes. At the same time, by providing a protection circuit consisting of a coil and a diode on the ground side of the xenon discharge tube, even if a diode is used to prevent mutual interference of the capacitors, the protection circuit functions and performs the protection operation. That can be done.

[0035]

According to the present invention, a protection circuit comprising a coil and a diode is provided on the ground side of a xenon discharge tube, so that even when a diode is used to prevent mutual interference between capacitors, the protection circuit can be used. The function can be demonstrated and the protection operation can be performed.

Thus, in the conventional device, when the diode is used to prevent the mutual interference of the capacitors, the function of the protection circuit may be hindered by the influence of the diode, and the protection operation may not be performed. According to the present invention, even when the mutual interference of the capacitors is prevented by using the diode, the function of the protection circuit can be exhibited and the protection operation can be performed.

Further, according to the present invention, by providing a differentiation circuit in the light emission current path of the xenon discharge tube, the waveform of the light emission current of the xenon discharge tube can be approximated to its light emission characteristics.

As a result, according to the present invention, various problems have occurred due to the difference between the current waveform flowing through the xenon discharge tube and the emission characteristics of the xenon discharge tube. These problems can be solved by approximating the emission current waveform of the tube to its emission characteristics.

Further, according to the present invention, by performing integration,
Even when the voltage fluctuates in continuous light emission or the like, a stable light amount can always be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an example of a strobe device to which the present invention is applied.

FIG. 2 is a diagram for explaining the operation.

FIG. 3 is a configuration diagram of an example of a conventional flash device.

[Explanation of symbols]

 Reference Signs List 1 Supply terminal for high voltage HV 2a, 2b, 2c, 2d Diode 3a, 3b, 3c, 3d Main capacitor 4a, 4b, 4c, 4d Diode for preventing mutual interference 5a Switching element (IGBT) 6a Resistor 7a Xenon discharge tube 8a Coil 9a Diode 10 Set signal terminal 11 Driver circuit 12 Capacitor 13 Resistor 14 Resistor 15 Capacitor 16 Detection transistor 17 Trigger signal terminal 18 Capacitor 19 Resistor 20 Thyristor 21 Resistor 22 Capacitor 23 Transformer

Claims (1)

[Claims] A strobe device comprising a main capacitor, a switching element, a control circuit thereof, a xenon discharge tube and a trigger circuit thereof, wherein a plurality of said main capacitors are connected in parallel via respective diodes, and said xenon discharge tube A protection circuit comprising a coil and a diode provided on the ground side of the strobe.