JPH0219795Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photographic strobe device, and more particularly to a strobe device having two light emitting sections, a main light emitting section and a sub light emitting section.

Recently, strobe devices having two main and sub light emitting sections with a light emission ratio of several to one have been put into practical use.

Such strobe devices are configured so that even when the main light emitting section that emits a large amount of light is directed towards the ceiling, the sub light emitting section that emits a small amount of light is always directly facing the subject. It is possible to enhance the effect.

Figures 1A and 1B show examples of electric circuits of conventional strobe devices having two main and sub light emitting sections as described above, both of which are of a type in which two light emitting circuits are controlled by one commutation circuit. It is.

The circuit in A of the same figure uses the energy of the main capacitor 2 charged by the high-voltage power supply 1 as a trigger circuit 4.
Due to the operation of
The power is simultaneously supplied to the sub-flash discharge tube 7, which has a small power capacity, through the first and second inductors 3, 5, and the main control switch element 8. It is appropriately controlled by a commutation circuit consisting of a current capacitor 9 and a sub-control switch element 10.

In such a circuit, two main and sub flash discharge tubes 6 and 7 are connected in parallel to one main capacitor 2. Therefore, if it is desired to set the power capacity of the main flash discharge tube 6 and the sub-flash discharge tube 7 and the light intensity ratio of the light emitted from the two discharge tubes to a desired number to one, the power will flow through the sub-flash discharge tube 7. The current must be made extremely small compared to that of the main flash discharge tube 7.

Therefore, a large second inductor 5 is required, and the power loss due to this second inductor 5 increases, and in order to compensate for this, a large capacity main capacitor 2 is required. Furthermore, the main control switch element 8 must have an extremely high withstand current because it must control a current that is a composite of the discharge currents flowing through the two main and sub flash discharge tubes.

From the above, the circuit shown in FIG. 1A cannot be said to be suitable for mass production, that is, for practical use, due to cost and size considerations.

The circuit shown in FIG. 1B is also a conventionally known circuit, but some of the problems of the circuit shown in FIG. 1A have been improved.

That is, as is clear from the drawings, the main flash discharge tube 6 and the sub flash discharge tube 7 are connected to independent first and second main capacitors 2 and 13, and first and second main capacitors 2 and 13, respectively.
and second inductors 3 and 5, etc.

Therefore, each of the first and second main capacitors 3, 1
The capacitance value of 3 only needs to be considered for the main flash discharge tube 6 and the sub-flash discharge tube 7, which each supply energy, which allows for a smaller design. The second inductor 5 connected to can also be small.

Therefore, the loss in the amount of light emitted is almost negligible, and a circuit that is more practical in terms of cost and size than the circuit shown in FIG. 1A can be obtained.

However, the current flowing through the main control switch element 8 that controls the light emission of the main and sub-two flash discharge tubes is a composite current of the current flowing through the main and sub-discharge tubes, as in the prior art example. For,
There is a problem in that the main control switch element 8 needs to have an extremely high withstand current.

The present invention was developed in consideration of the above-mentioned problems, and the discharge circuits of the main and auxiliary flash discharge tubes are formed independently, and the discharge current of the main flash discharge tube is changed from that of the auxiliary flash discharge tube. It is characterized by being configured so that it does not flow into the discharge circuit, and will be explained below with reference to the drawings.

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

In the figure, 14 and 15 are the main flash discharge tube 6,
First and second switch elements connected to the auxiliary discharge tube 7 and corresponding to the main control switch element in the conventional example that controls the amount of light emitted from these discharge tubes are shown;
16 indicates a diode for preventing backflow.

As is clear from the drawings, in the strobe device according to the present invention, when the trigger circuit 4 operates with the two main capacitors 2 and 13 fully charged,
The main flash discharge tube 6 consumes the charging energy of the first main capacitor 2 supplied via the first inductor 3 and the first switch element 14 to emit light.
At the same time, the secondary flash discharge tube 7 also has a second inductor 5,
The second
The charging energy of the main capacitor 13 is consumed to emit light.

When the sub-control switch element 10 becomes conductive due to a signal from a light receiving circuit (not shown), the first and second switch elements become non-conductive due to the discharge of the commutating capacitor 9, so that the main flash The light emission of the discharge tube 6 and the sub-flash discharge tube 7 is stopped.

Let us now consider the current flowing through the two main and sub flash discharge tubes.

Comparing the amount of light emitted by the main flash discharge tube 6 and the sub-flash discharge tube 7, we find that the main flash discharge tube 6
Needless to say, the amount of light emitted by the main flash discharge tube 6 is large, and therefore the current flowing through the discharge tube 6
The current is set so that it flows large and for a long time. It goes without saying that this setting can be easily achieved by selecting the characteristics of the second inductor 5 and the sub-flash discharge tube 7.

When the current flowing through each flash discharge tube is set as described above, the forward voltage drop of the first switch element 14 and the second switch element 15 becomes a voltage drop corresponding to the respective current. While connected, that is, the first and second switch elements 1
No current flows in the forward direction of the diode 16 between the high potential sides of the diode 4 and 15. That is, the current flowing through the secondary flash discharge tube 7 does not flow into the first switch element 14 through the diode 16.

On the other hand, the large current flowing through the main flash discharge tube 6 does not flow into the second switch element 15 due to the diode 16.

As a result, in the case of the strobe device according to the present invention,
Each of the discharge circuits of the main flash discharge tube 6 and the sub-flash discharge tube 7 has a commutation circuit that controls the amount of light emitted by each.
However, the only electrical common part is the ground, so they operate completely independently.

Therefore, the first and second switch elements 14, 1
5 should be selected to have a withstand current value for the current value flowing through the flash discharge tubes connected in series, that is, the combined current as in the conventional example shown in Fig. 1 A and B. Therefore, as the first switch element 14, a conventionally used element can be used, and as the second switch element 15, an element with a small withstand voltage can be used. , it is not necessary to select an element having a large withstand current such as the first switch element 8 shown in FIG. 1, which is expensive and has a large size.

In addition, the inductor connected in series with each flash discharge tube can also be small as in the conventional example shown in Figure 1B, and the problem of energy loss does not occur.
This means that the capacitance of the two main capacitors can also be small.

Although the explanation is later, for example, diode 1
6 is removed and the high potential sides of the first and second switch elements are connected directly. When the trigger circuit 4 operates and the main and sub two flash discharge tubes 6 and 7 emit light, the above 2. It is unlikely that the current flowing through the two switch elements will always be divided at the same ratio depending on the status of each flash discharge tube, and therefore, considering the variation in the characteristics of each switch element, the The switch elements 6 and 7 must be selected to have larger withstand current characteristics than necessary, and the strobe device according to the present invention shown in FIG. 2 is disadvantageous in terms of cost and dimensions. Needless to say.

As described above, in a strobe device having two main and sub flash discharge tubes, the present invention configures a discharge circuit for each of the main and sub flash discharge tubes using two main capacitors, two switch elements, etc. In addition, the characteristics of the diodes and flash discharge tubes, etc. are selected to prevent the current flowing through each flash discharge tube from flowing into the discharge circuit of the other flash discharge tube, and each discharge circuit is electrically independent. The present invention provides a strobe device which is characterized by a circuit, and which is extremely suitable for mass production in terms of cost and size and has high practical value.

[Brief explanation of the drawing]

1A and 1B are electric circuit diagrams showing a conventional example of a two-flash strobe device, and FIG. 2 is an electric circuit diagram of a two-flash strobe device according to an embodiment of the present invention. 2...First main capacitor, 3...First inductor, 4...Trigger circuit, 5...Second inductor, 6...Main flash discharge tube, 7...Sub-flash discharge tube, 9... Commutation capacitor, 13... second main capacitor, 14... first switch element, 15...
...Second switch element, 16...diode.

Claims (1)

[Scope of utility model registration request] A first main capacitor connected to both ends of a high voltage power supply such as a DC-DC converter circuit via a first diode and charged by the high voltage power supply;
a second main capacitor connected to both ends of the high voltage power supply via a second diode and having a smaller capacity than the first main capacitor, which is charged by the high voltage power supply; and the first main capacitor. a first series body consisting of a first inductor, a main flash discharge tube, and a first switch element connected in parallel; a second inductor and a sub flash discharge tube connected in parallel with the second main capacitor; a second series body consisting of a second switch element; the high potential side of the first switch element is connected to the cathode between the high potential side of the first switch element and the high potential side of the second switch element; A two-light lamp comprising: a third diode connected side by side; and a commutating circuit including a series body of a commutating capacitor and a sub-control switch element connected in parallel with the first switch element. Strobe device.