JPH0455310Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an electronic flash device suitable for flash photography using a plurality of electronic flash devices.

2. Description of the Related Art Conventionally, electronic flash devices known as so-called high-voltage strobes are known in which a high voltage is output to one end of a test flash switch or a synchro contact switch. (Hereinafter, such an electronic flash device will be referred to as a high-voltage strobe.) Figure 5 shows an example of a circuit for a high-voltage strobe, which includes a power supply E2, a DC-DC converter 2, a rectifier diode D2, a main capacitor C3, and a xenon tube. Xe2, resistor R6, trigger capacitor C4, trigger transformer T2, and test flash switch SW4.
4 is connected in parallel to the test light emission switch SW4.

Test flash switch used in this circuit
Since SW4 is connected between the high voltage V1 of the main capacitor C3 and the ground via the resistor R6, it must have a high withstand voltage. Furthermore, since a high voltage is applied to both ends of this switch SW4, if the impedance of this switch SW4 is high, even if this switch SW4 is closed, the connection point J1 with the resistor R6 will not go to the "Low" level. Xenon tube Xe2 may not be triggered. Therefore, the test light emission switch SW4 used in the above circuit needs to be a switch with low impedance and high withstand voltage. Such switches are generally expensive. On the contrary,
In order to solve the above problems and reduce costs,
An electronic flash device as shown in FIG. 6 can be considered.
In the circuit of FIG. 6, the same members as those in FIG. 5 are denoted by the same numbers and their explanations will be omitted. SCR2 is a thyristor used in place of the test light emission switch SW4 in Fig. 5, and its gate terminal is connected to the resistor R9.
Connect to the connection point of R10 and connect the transistor
The above resistors R9 and R1 are connected to the power supply E2 via Tr2.
0. And this transistor Tr
The base of 2 is connected to the connection point of resistors R7 and R8, one of the resistors R7 is connected to the power supply, and the other resistor R8 is connected to the test light emission switch SW4 and the synchro contact switch SW3, respectively. Then, when the test light emission switch SW4 or the synchro contact switch SW3 is turned on, the transistor is turned on.
Tr2 is turned on, the gate terminal of thyristor SCR2 becomes "H", thyristor SCR2 is turned on, xenon tube Xe2 is triggered, and flash light is emitted.

Since the test flash switch SW2 used in the electronic flash device shown in FIG. 6 is connected between the power supply and ground, the maximum voltage applied thereto is the power supply voltage. For this reason, this switch SW4 does not need to withstand voltage or have low impedance, and thus a low-cost switch can be used.

Incidentally, as a photographing method, multiple flash photography is known in which a plurality of electronic flash devices are connected in parallel and emit light simultaneously. The electronic flash device used for this photographing is the electronic flash device shown in FIG. 6, in which high voltage is not applied to the test flash switch SW4 and the synchro contact switch SW3, and the conventional electronic flash device shown in FIG. It is desirable for users to be able to perform the above-mentioned multi-flash photography even when used in combination with a high-pressure strobe such as a high-pressure strobe.

However, if the electronic flash device shown in FIG. 6 and the high voltage strobe shown in FIG. 5 are connected in parallel, the voltage V1 of the high voltage strobe shown in FIG. Transistor Tr2 of the device is destroyed and its function (switching)
A problem arises in that it no longer fulfills its purpose.

Furthermore, when using a plurality of these electronic flash devices and attempting to perform a test flash with only one flash device, when the test flash switch of that one electronic flash device is turned on, the connection through the connection terminal Te4 will occur. A trigger is applied to all electronic flash devices, causing them to emit light. Therefore, it is impossible to measure the light emitting characteristics of the electronic flash device that is attempting to emit test light, and furthermore, the power of other electronic flash devices is consumed.

Therefore, in order to prevent high voltage from being applied to the above-mentioned test flash switch, one side of this switch is connected to the power supply via the switching circuit, and the other is connected to the ground, and even if it is connected in parallel with the high voltage strobe, the switching circuit is not destroyed,
And the test flash switch for this flash device.
In order to prevent other flash devices from emitting light even when the switch is turned on, a diode is connected in the opposite direction to the connection point between the above switching circuit and the test flash switch via a contact that is electrically connected to the camera's synchronization contact. Electronic flash devices are known.

Problems to be Solved by the Invention Incidentally, in order to cope with the diversification of photographing conditions, an electronic flash device is sometimes provided with a photographing condition changeover switch such as a film sensitivity setting switch or a guide number changeover switch. In such a case,
Separate molding of each switch, including the test flash switch, increases the number of parts and costs.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic flash device that is low in cost and can perform test emission.

Means for Solving the Problems In order to achieve the above object, the electronic flash device of the present invention includes a power supply battery, a booster circuit that boosts the voltage of the power supply battery, and a test flash switch whose one end is grounded. , a switching circuit that is supplied with power from the battery and is connected to the other end of the test flash switch and activated in response to the opening/closing operation of the test flash switch, and a contact that is electrically connected to the synchronization contact of the camera. and a diode whose cathode is connected to this contact, and whose anode is connected to the connection point between the test light emission switch and the switching circuit, which is connected in parallel to the booster circuit and the main capacitor, and is connected in parallel to the switching circuit. It is an electronic flash device equipped with a trigger circuit that triggers the flash tube when activated, and a shooting information changeover switch that changes the shooting information. It is characterized by being integrally molded with impedance material.

Embodiment FIG. 1 shows a circuit diagram of an electronic flash device according to an embodiment of the present invention. In Fig. 1, E1 is a power supply, 1 is a DC-DC converter that boosts the power supply E1, D1 is a rectifier diode that rectifies the output of the DC-DC converter 1, and C2 is a main unit that accumulates charges for flash emission. Capacitor, Xe1, discharges the charge stored in the main capacitor C2,
A xenon tube that emits flash light, T1 is a trigger transformer that triggers flash light emission, C1 is a trigger capacitor, SCR1 is a trigger thyristor, R5 is a resistor, SW2 is a test flash switch, D2 is a high voltage prevention diode, and Tr1 is a Powered by power supply E1, test flash switch SW
2 or by turning on synchro switch SW1,
Operates through resistors R1 and R2, and resistors R3 and R4
The transistors Te1 and Te2 that trigger the thyristor SCR1 are connection terminals for electrical connection to the camera side. SW1 is a synchro switch provided on the camera body side, and connection terminal Te1,
It is connected to an electronic flash device via Te2.

Such an electronic flash device and a high-voltage strobe as shown in Figure 5 are connected to the camera's synchronization switch SW.
1, the charging voltage V1 of the high voltage strobe is applied to the connection terminal Te1, but a high voltage prevention diode D2 is provided at the connection point J2 between the test flash switch SW2 and the resistor R2. Because of this, high pressure is not applied. Therefore, transistor Tr1 will not be destroyed. Also, switch SW2 for the test flash of this electronic flash device.
Even if it is turned on, the connection terminal Te1 is connected to the high voltage prevention diode D2, so it will not go to "Low" level, so other electronic flash devices will not emit light.

Furthermore, the test light emission switch includes resistors R1,
Since it is connected to the power supply via R2, high voltage is not applied, and a switch with low withstand voltage and high impedance can be used.

Figures 2A to 2C show an example in which a conductive rubber switch is used as a low voltage and high impedance switch. Figure 2A is a plan view, Figure 2B is a sectional view taken along line A-A' in Figure 2A, and Figure 2C is a sectional view of the
FIG. 2 is a sectional view taken along line BB' in FIG. B in the figure,
In C, the part indicated by a-1 is conductive rubber, and the part a-2 is insulating rubber. In Fig. 2 A, a plurality of insulating rubber parts a-2 are integrally molded into a string shape.
In each case, a conductive rubber part a-1 is attached to a recessed part of an insulating rubber part a-2. The shape of the integrally molded switch containing these conductive rubbers may be changed depending on the location and number of switches to be installed. Also, make the above switches in a matrix shape,
You can cut it into the desired shape.

FIG. 3 shows an external view of the main body of an electronic flash device in which the switch shown in FIG. 2A described above is provided. E
1 is a test flash switch, F2 is a film sensitivity setting switch, F3 is a guide number selection switch, F4 is a flash illumination angle change switch, F5
is a flash lighting direction change switch. F2
F5 to F5 may be a focus detection auxiliary light emission switch, a distance setting switch, or the like.

FIG. 4A shows the state in which the switches F1 to F5 are actually arranged inside the main body of the electronic flash device. H is the outer cover of the main unit, I
indicates a circuit board. FIG. 4B shows the wiring pattern of the portion of the circuit board I corresponding to the test light emission switch F1 that comes into contact with the conductive rubber a-1. pt
1 indicates a pattern wired to the (-) side of the battery, and pt2 indicates a pattern wired to the resistor R2 and high voltage prevention diode D2 shown in FIG.

Effects of the invention As detailed above, according to the invention of the present application, one end of the switch for test light emission is connected to the power supply via the switching circuit, and the other end is connected to the ground, so that high voltage is applied to this switch. Not done. Therefore, the test light emission switch may be a low-cost, low-voltage, high-impedance switch. Furthermore, since the test flash switch is integrally molded with the shooting information switch, the number of parts and manufacturing steps can be reduced, further lowering the cost of the electronic flash device. be able to.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention, FIGS. 2A to 2C show a plurality of conductive rubber switches including a test light emission switch used in the embodiment, and FIG. 2A is a plan view; Figure 2B is a sectional view taken along A-A' in Figure 2A, and Figure 2C is B in Figure 2A.
-B' cross-sectional view, Figure 3 is an external view showing the switch shown in Figure 2 used in the main body of an electronic flash device, and Figure 4 A shows the state of the conductive rubber switch inside the electronic flash device. 4B is a pattern diagram showing a wiring pattern printed on a printed wiring board and made conductive by pressing a conductive rubber switch, FIG. 5 is a circuit diagram of a conventional electronic flash device, and FIG. It is a circuit diagram of an electronic flash device that was conceived prior to the invention. Te2... synchro contact, D2... diode, SW1... synchro switch, SW2... test flash switch means, E1... power supply battery,
Tr1, R1 to R4...Switching circuit, SCR
1, R5, C1, T1...Trigger circuit, C2...
main capacitor.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A power source battery, a step-up circuit for boosting the voltage of the power source battery, a test light emission switch whose one end is grounded, and a test light emission switch which is supplied with power from the battery and which operates the test light emission switch. a switching circuit connected to the other end and activated in response to the opening/closing operation of the test flash switch; a contact electrically connected to the synchronization contact of the camera; and a cathode connected to this contact.
a diode whose anode is connected to the connection point between the test flash switch and the switching circuit; a trigger circuit connected in parallel to the booster circuit and the main capacitor to trigger the flash tube upon activation of the switching circuit; An electronic flash device equipped with a photographing information changeover switch for changing information, wherein the test flash switch and the photography information changeover switch are integrally molded from a material with low withstand voltage and high impedance. An electronic flash device featuring: 2. The electronic flash device according to claim 1, wherein the low voltage and high impedance material is conductive rubber.