JPS5935480B2 - electronic flash device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a means for causing an electronic flash device to emit light at regular intervals, for example, to warn a traffic accident at night, or to alert a third party with an instantaneous light. It is something.

Conventional methods for automatically causing an electronic flash device to emit light include methods (1) and (2) below.

(1) When the secondary voltage reaches the specified voltage, output a trigger output to emit light.

(2) An oscillator is separately provided, and light is emitted by trigger output from the oscillator at regular intervals.

In method (1), as shown in FIG. 1, the secondary voltage is divided by a series circuit of resistors 1 and 2 and applied to the gate of the thyristor 3.

When the voltage generated in the resistor 2 becomes a voltage that makes the thyristor 3 conductive, the thyristor 3 becomes conductive and the xenon discharge tube 4 emits light.The above method (1) can easily extract the trigger output, but the xenon discharge Since the voltage that causes the tube 4 to emit light is constant, the time it takes to reach the specified voltage becomes slower as the power source battery 5 wears out, making it impossible to emit light at regular intervals.

The method (2) above uses a pulse oscillation circuit 1 as shown in FIG.
By applying the oscillation output of the UJT 6 to the gate of the thyristor 3 and making the thyristor 3 conductive, the xenon discharge tube 4 is made to emit light at regular intervals. .

Note that γ indicates an oscillation transistor, and 8 indicates an oscillation transformer.

The present invention eliminates the above-mentioned drawbacks (1) and (2), and has the feature that it emits light at approximately constant intervals and does not require a pulse oscillation circuit for this purpose.

An embodiment of the present invention will be described below with reference to FIG.

In FIG. 3, in an oscillation circuit composed of a transistor 1, an oscillation transformer 8, a resistor 9, and a capacitor 10.11, when a switch 12 is turned on, a signal flows from the power supply battery 5 through the resistor 9 to the transistor γ. A current flows, which causes a collector current to flow, and a voltage proportional to the change in the collector current is generated in the feedback winding 8a, and the transistor 1
The voltage is positively fed back to the base of the transistor 1, and the transistor 1 oscillates.

When the amount of positive feedback is large, the voltage generated in the base winding 8a is charged to the capacitor 10 with the polarity shown in the figure due to the rectification effect between the base and emitter of the transistor γ, and the transistor 1 continues to oscillate. It becomes impossible and oscillation stops.

When the oscillation stops, the capacitor 10 is no longer charged, the charge of the capacitor 10 is discharged by the resistor 9, the terminal voltage of the capacitor 10 becomes low, and the transistor 1
When it becomes possible to re-oscillate, the transistor γ resumes oscillation and enters a blocking oscillation state in which the above-described operation is repeated.

When the amount of positive feedback is small or when the load condition is heavy, the voltage generated in the base winding 8a becomes low, so the voltage charged in the capacitor 10 is low enough to stop the oscillation of the transistor 1. Since this is not possible, continuous oscillation occurs at a frequency determined by the oscillation transformer 8, capacitor 11, etc.

The present invention utilizes the above-mentioned characteristics to perform continuous oscillation when the main capacitor 13 has not reached the saturation voltage, that is, when the load is heavy, and to perform blocking oscillation when the main capacitor 13 reaches the saturation voltage. Set resistance 9 to .

Since the resistor 9 is also a load on the base winding 8a, if the resistance value is made small, the transistor 1 becomes continuous oscillation.

FIG. 4 shows the voltage waveforms of various parts when the resistor 9 is set to perform blocking oscillation as described above, and 4-a is the collector voltage of transistor 1, and 4-a is the collector voltage of transistor 1. b is the voltage of capacitor 10, 4-c is the voltage of capacitor 10,
4 is the waveform of the differential voltage output to the resistor 15 through the resistor 15.

The period T in FIG. 4 indicates the period during which the main capacitor 13 is being charged;
When approaches saturation, the feedback current flowing through the closed loop consisting of the emitter-base of transistor γ, the main capacitor 13, the power supply 5, etc. decreases, and the charging voltage of the capacitor 10 increases in the direction of blocking this current. The influence becomes so great that eventually the transistor γ becomes non-conductive, the main capacitor 13 becomes saturated, and the oscillation stops.

Thereafter, as mentioned earlier, the charge charged in the capacitor 10 is discharged through the resistor 9, and when the charged voltage drops to a level that allows the transistor 1 to re-oscillate, the oscillation operation is performed again, and such an operation is performed from now on. is repeated as shown in Figure 4-4-a, resulting in a blocking oscillation operation, and the period at this time is equal to the capacitor 10 and resistor 9.
In addition, T2 is determined by the feedback current value.

Furthermore, when the blocking oscillation operation as described above is performed, the charging voltage of the capacitor 10 and the differential output of the voltage of the capacitor 10 outputted to the resistor 15 through the capacitor 14 are shown in FIGS. 4-b and 4-c, respectively. There is no need to explain in detail how this happens.

Further, in the circuit configured to perform blocking oscillation as described above, the present invention further provides a pulse 11, which is the differential output shown in FIG. is used as a gate signal for the thyristor 3.

In other words, if a blocking oscillation operation is performed, the fourth
This results in the pulse 11 shown in Figure 4-c.
The thyristor 3 is made conductive by the pulse 11, and the main capacitor 13 is turned on every time the pulse 11 is generated.
The charge is consumed by the xenon discharge tube 4 to emit light.

Therefore, in the case of the electronic flash device according to the invention, switch 1
2, the first pulse 11 that appears causes the xenon discharge tube 4 to emit light, and the charge in the main capacitor 13 is consumed.The waveforms of each part as explained in FIG. 4 are as shown in FIG. Unlike T1, which was explained earlier
and T2 appear as a set, that is, after the first pulse 11 appears, the charge in the main capacitor 13 has been consumed, so the charging operation indicated by T1 is performed again until the saturation state is reached. After reaching the saturated state, the next pulse 11 will be generated after the period T2 has elapsed, and needless to say, the xenon discharge tube 4 will repeatedly emit light at a cycle of T1+T2. Become.

Here, the time T1 until the main capacitor 13 reaches the saturation voltage becomes longer due to consumption of the power supply battery 5, but the period T1 of the switching oscillation determined by the resistor 9 and the capacitor 10
2 becomes shorter, the light emission interval T1+T2 becomes approximately constant.

This can be understood from the fact that, as described above, the period T2 based on the blocking oscillation operation is determined by the values of the capacitor 10, the resistor 9, and the feedback current.

That is, when the power supply battery 5 is depleted, the electric charge stored in the capacitor 10 is less than when it is not depleted because the voltage generated in the coil 8a is lower and the feedback current value is also smaller. As a result, the time required for the capacitor 10 to discharge and drop to a voltage that allows the transistor T to re-oscillate becomes shorter.

In other words, when the power supply battery 5 is not exhausted, the voltage generated in the coil 8a is high, and the charging voltage value of the capacitor 10 is also high, and the transistor γ quickly reaches a level that would normally make it non-conductive. However, due to the high voltage generated by the secondary coil, a large amount of feedback current flows between the emitter and base of the capacitor 13, the power supply battery 5, and the transistor 7, so it takes a long time to reach the saturated state of the capacitor 13. Therefore, it takes a long time to discharge the charge stored in the capacitor 10.

Furthermore, to put it simply, the period T2 can be said to be the time from when the charge in the capacitor 10 is discharged through the resistor 9 from when the transistor 1 is turned off until the transistor 1 re-oscillates. When the power source battery 5 is depleted, the non-conducting timing of the transistor γ varies regardless of the amount of charge in the capacitor 10 depending on the degree of depletion of the power source battery 5. , the period T2 becomes shorter.

FIG. 5 shows the experimental results of the embodiment of the present invention and the experimental results of the conventional example shown in FIG. This example shows the characteristics that are caused by the difference in the initial setting waste light interval.

゛As can be seen from Figure 5, in the conventional example, as the blinking time elapsed (that is, as the number of flashes increased), the power supply voltage decreased, so when the battery was new, the flash interval was 0.5 seconds as indicated by the broken line 5b. After 30 minutes of continuous lighting, it will take about 4 seconds, and after 1 hour, it will take about 10 seconds.

On the other hand, in the case of the present invention, if the initial time is set to about 2 seconds, it will be 2.1 seconds after 30 minutes, 2.2 seconds after 1 hour, and 3 seconds after 30 minutes.
The time is 3.3 seconds, and the interval of light emission can be kept almost constant without being affected by fluctuations in the power supply battery voltage.

This means that, for example, when the present invention is used as a warning light to indicate a traffic accident, or as a display means to call attention to a third party, such as a sign light, the emitting interval may be extended as in the conventional example. It serves no purpose as a wake-up call and cannot emit light at regular intervals as in the present invention, and this is an important and essential element in, for example, warning lights for accident indications, which can also affect human life. It is.

As described above, the present invention effectively utilizes the voltage generated in the feedback circuit of the oscillation circuit to generate a predetermined periodic pulse signal, and there is no need to specially provide the pulse oscillation circuit 16 as in the conventional example. Furthermore, since no additional circuit components are required to obtain the pulse signal, the device can be made inexpensive, and has various features such as eliminating defects caused by irregularities in light emitting intervals.

[Brief explanation of the drawing]

1 and 2 are electric circuit diagrams showing a conventional example of automatically causing an electronic flash device to emit light, FIG. 3 is an electric circuit diagram showing an embodiment of the electronic flash device of the present invention, and FIG. The figure is the third
A time chart is shown for explaining the operation of the embodiment shown in the figure, and FIG. 5 is a graph showing an experimental comparison between the electronic flash device of the present invention and a conventional example. 3...Thyristor, 4...Xenon discharge tube, 5...Power battery, 1...Transistor, 8...Oscillation transformer, 9・・・・・・
Resistor, 10... Capacitor, 13...
Main capacitor, 14... Capacitor, 15...
····resistance.

Claims (1)

[Claims] 1 The energy from the power supply battery is boosted through a DC-DC converter circuit consisting of an oscillation transformer consisting of a primary winding, a feedback winding, and a secondary winding, an oscillation transistor, etc., and the main capacitor is charged with a high voltage. A flash light source that emits a predetermined flash by discharging the charging energy of the main capacitor to a xenon discharge tube, and a trigger transformer (Kosairisuku) consisting of a primary winding and a high voltage winding that transfer the energy of the trigger capacitor that is dividedly charged from the main capacitor to a xenon discharge tube. In an electronic flash device comprising a trigger circuit for triggering the xenon discharge tube by emitting light through a switching element such as A trigger means for applying a voltage generated in the capacitor in the feedback circuit consisting of a parallel circuit and a power supply battery to the switching element via a differentiating circuit to cause the flash light source to emit light at approximately constant intervals. An electronic flash device characterized by having: