JPS5821798B2 - electronic flash device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic flash device using a multiple flash electronic flash device.

Conventionally, for the purpose of erasing the shadows of relatively large subjects, or of the subject in light lighting, an irradiation method is often used in which multiple electronic flash devices are arranged in multiple directions and multiple flashes are fired. .

The problem with this type of irradiation method is that it is very difficult to set the exposure conditions on the camera side because multiple electronic flash devices emit flash light onto the subject after passing through various irradiation distances. It was necessary to repeatedly take multiple shots and find the appropriate exposure conditions empirically.

Therefore, as a means to solve this problem, a number of electronic flash devices arranged on multiple sides have recently been equipped with a dimming function to receive the reflected light from the subject installed on the camera side. When the amount reaches a predetermined value, a stop signal is transmitted from one light receiving section that generates a light emission stop signal to the plurality of electronic flash devices having a dimming function, and the light emission is stopped. This method eliminates the trouble of determining exposure conditions empirically.

However, in this case, control signals are transmitted from one light receiving section provided on the camera side to each electronic flash device via lead wires, so if the subject becomes large,
The lead wires become longer, and as the number of multiple electronic flash devices increases, the number of lead wires must also increase correspondingly. There was the above annoyance.

Furthermore, depending on the photographing conditions, there is a fear that the lead wire may be imprinted inside the subject.

The present invention eliminates such drawbacks and will be explained below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, and first, a well-known automatic dimming electronic flash device for controlling the multiple flash electronic flash device of the present invention will be explained.

Dashed line 1 is automatic dimming. A circuit diagram of an electronic flash device is shown in which the main discharge capacitor 2 is charged via a power source 3 such as a well-known laminated battery or a relatively low voltage power source battery via a DC-DC converter circuit. charged to a voltage of

The charged energy is excited by the trigger circuit 5 and then released into the flash discharge tube 4, which begins to irradiate the subject with light based on the flash waveform shown in FIG. 2a.

On the other hand, the reflected light from the subject based on the flash waveform is
When the light is received by the light receiving sensor 6 installed in the housing of the automatic dimming electronic flash device and the cumulative amount of light reaches a predetermined value, the bypass tube 7 connected in parallel with the flash discharge tube 4 is turned on by the optical integration circuit 8. The energy from the main discharge capacitor 2 is bypassed to the bias tube 7, and the light emission is stopped at a time when ΔT shown in FIG. 2 has passed, for example.

Therefore, when the light adjustment operation is performed, the flash waveform becomes the state shown by the diagonal lines, and provides an appropriate amount of light to the subject.

In the present invention, such an auto-adjusting electronic flash device is set on the camera side, and a plurality of multiple electronic flash devices, which are appropriately arranged depending on the size of the subject or photographing conditions, are used as the auto-adjusting electronic flash device. It is controlled by a flash of light from the device 1, and the amount of light reflected from the subject that enters the camera is set to a proper exposure.

In other words, the integrated amount of light integrated by the light integrating circuit 8 of the auto-adjusting electronic flash device 1 installed on the camera side is the amount of light reflected from the subject by the auto-adjusting electronic flash device 1 on the camera side and the amount of light reflected from the subject by the auto-adjusting electronic flash device 1 on the camera side. The amount of light received is the sum of the amount of light reflected from the subject by the electronic flash device (hereinafter referred to as the amount of received light), and the timing when the bypass discharge tube of the automatic light control electronic flash device 1 is operated is related to the total amount of received light. Therefore, the total amount of light received ultimately corresponds to the flash waveform from the automatic dimming electronic flash device 1.

Therefore, in the present invention, it is possible to control the light emission of a plurality of multiple electronic flash devices arranged with respect to the subject using a flash waveform corresponding to the total amount of light received, so that the subject that is substantially incident on the camera side can be controlled. This is an attempt to make the amount of light reflected from each other an appropriate amount of light corresponding to the total amount of light received.

A multiple electronic flash device 9 for achieving this circuit is shown in FIG.

In the figure, parts having the same functions as those of the automatic dimming electronic flash device 1 are given the same numbers with dashes and will not be described in detail.

First, the flash discharge tube 4 of the corresponding main electronic flash device is attached to the above-mentioned auto-adjustable electronic flash device installed on the camera side as shown in Fig. 2a.
When the flash light starts to emit light having the flash waveform shown in FIG.

Now, the charging voltage of the main discharge capacitor 2 is applied to the light receiving sensor 10 via a first constant voltage circuit 15 consisting of a dividing circuit consisting of a resistor 11 and a resistor 12 and a constant voltage element 14 via a resistor 13. Therefore, the reflected light from the subject is converted into a photocurrent by the light receiving sensor 10, and a voltage corresponding to the flash waveform is generated across the resistor 16.

For example, if the flash waveform produced by the main electronic flash device 1 is shown in FIG. 2 a, the voltage waveform across the resistor 16 is shown in b.

Therefore, the voltage across the resistor 16 is passed through a differentiating circuit consisting of the capacitor 17 and the resistor 18 in the next stage, so that the voltage across the resistor 18 is applied to the first voltage at the rise time t2.
An output signal d is generated.

This output signal d is applied as a first trigger to the gate of the thyristor 20 of the circuit 5' through the resistor 19, so that the thyristor 20 becomes conductive and operates the first trigger circuit 5'.

As a result, the flash discharge tube 4' is triggered and releases the energy from the main discharge capacitor 2' to begin a flash.

Thereafter, the amount of flash light from the main electronic flash device 1 and the amount of flash light from the multiple electronic flash device 9 are weighted together to capture the subject 21.
The amount of superimposed flash light is reflected from the subject, and the amount of linear light received is received by the light receiving sensor 6 of the main electronic flash device 1, and the photocurrent from the light receiving sensor 6 is transmitted to the optical integration circuit 8.
It is integrated at

When the integrated amount reaches a predetermined value, the bypass discharge tube 7 in the main electronic flash device becomes conductive and stops the flash from the flash discharge tube 4, so the flash waveform from the main electronic flash device 1 becomes Integration time △ corresponding to the total amount of light received as shown in Figure 2 a
It sharply drops to zero after T.

The flash waveform of the main electronic flash device 1 is also received at the same time by the light receiving sensor 10 of the multiple electronic flash device 9, but since the photocurrent is outputted via a differential circuit consisting of a capacitor 17 and a resistor 18. , substantially only the steep change in the light waveform after △T of the flash waveform a is caused by the resistance 18.
is output from both ends as a differential waveform e.

Since this differential waveform e has the opposite polarity to the output waveform d at the previous rise, this output is applied to the next stage transistor 21' without making the thyristor 20 of the first trigger circuit 5' conductive. .

By the way, Transis. Since the transient power shown in FIG. 2 f is not applied to the collector of the transistor 21' from the chain line 23 via the resistor 22, a waveform that is an inversion of the waveform e is generated between the collector and emitter of the transistor 21'. The waveform g is applied to the gate of the second trigger circuit 23 and the thyristor 24 for generating the bypass discharge tube 7'k) IJ.

As a result, the thyristor 24 becomes conductive, applies a trigger pulse to the bypass discharge tube 7' to operate the bypass discharge tube 7, and stops light emission from the flash discharge tube 4'.

In this example, a bypass tube is connected in parallel with the flash discharge tube to bypass the charging energy of the main discharge capacitor. - Using a so-called serial system in which light emission is controlled by off-control is used for both the main electronic flash device and the multiple electronic flash device, the light emission control of C can be performed in the same way.

As described above, the present invention causes the multiple electronic flash device to emit light by the light emission of the main electronic flash device, and stops the multiple electronic flash device from emitting light by changing the cut-off light at a time corresponding to the total amount of light received by both devices. This is how it was done.

Therefore, the amount of light emitted from the multiple electronic flash device can be controlled in relation to the total amount of light received by the main electronic flash device installed on the camera side. Lead wires for signal transmission can be completely eliminated.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram of an electronic flash device which is an embodiment of the present invention, and FIG. 2 is a waveform diagram for explaining the device. 1... Main electronic flash device, 9... Multiple electronic flash device,
21...Subject.

Claims (1)

[Claims] 1. A first main discharge capacitor and a first flash discharge tube that emit light by consuming the charge of the main discharge capacitor and the light from the flash discharge tube are irradiated onto a subject and the reflected light is a main electronic flash device including a first light receiving means for receiving light and a first light emission stop circuit that stops light emission of the first flash discharge tube when the amount of light received by the first light receiving means reaches a predetermined value; A second flash discharge tube that emits light by consuming the charge in the capacitor and the second main discharge capacitor; and a trigger pulse is applied to the second flash discharge tube to cause the second flash discharge tube to emit light. connected to a trigger circuit, a second light emission stop circuit that stops light emission of the second flash discharge tube, and a second light receiving means that receives light from the first flash discharge tube and converts the amount of received light into an electric current. The trigger circuit is operated in synchronization with the light emission of the first flash discharge tube, and in response to the end of light emission of the first flash discharge tube by the first light emission stop circuit, the second
1. An electronic flash device comprising: an operation signal generation circuit that generates a signal for operating a light emission stop circuit; and a multiple flash electronic flash device. 2. The operation signal generation circuit includes a differentiating circuit that converts the photocurrent obtained by the second light receiving means into a voltage and differentiates the voltage;
Claim 1, comprising: a power supply circuit connected in parallel with the second main discharge capacitor; and a switch circuit operated by the power supply of the power supply circuit and the output of the differentiating circuit. The electronic flash device according to item 1.