JPS58102225A - Automatic dimming electronic flash device - Google Patents

Abstract

PURPOSE:To prevent failure of photographing, by starting an operation by synchronizing with light emission of a flash tube, completing the opration as soon as the light emission ends, measuring a light emission interval, displaying the light emission interval, and displaying whether the light emission is within the effective distance range or not. CONSTITUTION:When a switch 1 is turned on, a DC power supply 2 is converted to a boosting DC by a DC-DC converter 3, and a main capacitor (C) 4 is charged. Voltage of C4 oprates a triggering circuit 5, and a flash tube 6 generates a flash and irradiates an object to be photographed. By synchronizing with light emission, a clock generating circuit 12 is operated, and is counted by a counter 13. Also, supply voltage generating circuit 8 supplies electric power to a photodetecting circuit 9, a reflected ray of the object to be photographed is photodetected by a photodetector 10, and is integrated by an integration cricuit 11. When an integral value reaches a prescribed value, the circuit 9 generates a light emission stop signal, a light quantity controlling circuit 7 operates, and light emission of the flash tube 6 is stopped. At the same time, said signal is applied to an operating circuit 14 through an A/D converting circuit 17, and is operated with a counting signal of the counter 13. The operating output is displayed as to a range, on a display part 16 through a decoder 15.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic light control electronic flash device that can automatically control the amount of light emitted and is useful for photography, and in particular to an automatic light control electronic flash device that has a function of displaying the effective distance range for controlling the light amount. Regarding flash devices.

There is a limit to the amount of light emitted by an electronic flash device, but if the light emission is outside the effective distance range where light emission can be controlled, there will be a 'rr% lack of light, which is an inconvenience that you will notice a failure after finishing printing the film. have.

The present invention has been developed in view of this problem, and is capable of preventing failures in photographing by displaying whether or not light is emitted within an effective distance range, and will be described with reference to the drawings.

FIG. 1 shows an electric circuit diagram of an embodiment of an automatic dimming electronic flash device of the present invention.

In the figure, when switch 1 is turned on, the direct current 'Ichihara 2 is D
The C-DC converter 3 converts it into step-up direct current, which charges the main capacitor 4, and the voltage is applied to the flash tube 6.
When the value at which light can be emitted is reached, the trigger circuit 6 is activated to emit a trigger pulse, which causes the flash tube 6 to consume the photoelectric energy of the main capacitor 40 and emit a flash to illuminate the subject. The clock pulse generating circuit 1 is synchronized with the operation of the trigger circuit 6, that is, with the flash tube 60 emitting light.
2. Clock pulses are generated, and these clock pulses are counted by the counter 13.

On the other hand, in synchronization with the light emission of the flash tube 60, the power supply voltage generating circuit 8 generates a power supply voltage to the light receiving circuit 9, whereby the reflected light from the object is received by the light receiving element 10 and integrated by the integrating circuit 11.

stomach. Kakei. 8, 10, yo, oka, a light emission stop signal is issued from above, and the light amount control circuit 7 is activated by this.
Light emission from the flash tube 6 is stopped.

At the same time, an output signal is given from the light receiving circuit 9 to the A-D conversion circuit 17, where it is converted into a digital signal and inputted to one side of the arithmetic circuit 14.
3 count signals are calculated and the calculated output is input to the decoder 16'. The decoder 15 operates in response to the calculation output of the calculation circuit 14 and outputs a distance display signal, and the display section 16 displays the distance in response to this signal.

Here, distance display will be described when light emission control is performed, that is, when there is a subject within the effective distance range and when there is not.

First, when the distance is within the effective range, the integrating capacitor (not shown) in the integrating circuit 11 is charged to a predetermined level VT for stopping light emission, as shown in FIG. 4, the output signal given to the A-D converter circuit 17 is VT, and the digital signal obtained by A-D converting this value is O''. This becomes the signal itself, and the distance is indicated by this signal.

On the other hand, if the subject is far away and outside the effective distance range, the charge level of the integrating capacitor will remain vl or v2 even after the flash tube 60 has finished emitting light, as shown in FIG.
It will be like this.

In this case, the predetermined levels VT-, V1. VT-V2
Alternatively, the signals of V, , v2 are manually input to the A-D conversion circuit 17, and a digital signal "1" or "2", which is different from the above-mentioned "0", is output depending on the magnitude of each signal, This signal is input to the arithmetic circuit 14.

On the other hand, since the light receiving circuit ← e does not issue a light emission stop signal, the flash tube 6 behaves as if it were manually emitted, and the clock pulse generation circuit 12 generates a clock pulse between all light emissions, and turns on the power at the same time as the light emission ends. When the power supply voltage generation circuit 8 no longer generates a light emission signal, a light emission end signal is sent to the clock pulse generation circuit 12, and thereby no clock pulse is generated.

Therefore, the counter 13 counts the black pulses and pulses between all the flashes of the flash tube 6, and this counting signal is input to the calculation circuit 14, where it is calculated with the 8-D converted digital signal, and the decoder: 16, it is converted into a distance signal and displayed on the display section 16.
is displayed.

FIG. 3 shows an electric circuit diagram of another embodiment of the automatic dimming electronic flash device of the present invention, and the same numbers as in the previous embodiment indicate the same functions and will not be particularly described.

In the figure, 19 indicates a film sensitivity setting circuit, and 2
0 indicates a circuit that is set according to the aperture value of the camera,
Each has one film feeling for use and one aperture to use.
By setting 9 and 20, the operation level of the light receiving circuit 9 is adjusted and light emission control is enabled.

In this embodiment as well, the output signal from the arithmetic circuit 14 when the subject is within or outside the effective distance range is output in the same manner as in the previous embodiment, and is input manually to one of the arithmetic and Q circuits 18.

On the other hand of the calculation circuit 18, there is a film sensitivity setting circuit 1.
9 and the output signal calculated by the arithmetic circuit 21 based on the output signal set by the aperture value setting circuit 20. This signal is here calculated into the output signal from the arithmetic circuit 14, and the output signal is sent to the decoder circuit 16. A distance display signal is input, and the display unit 16 displays the distance.

The display on the display section 16 can be made by, for example, lighting up a light-emitting display such as a lamp or light-emitting diode corresponding to the distance index as shown in FIG.
) may be displayed, and it is only necessary to judge whether the distance displayed is within the effective distance range.

As described above, since the automatic light adjustment type f-flash device of the present invention is provided with a distance display of the subject, it is possible to check whether the subject is within the effective distance range for shooting, thereby solving the problem mentioned at the beginning. can be made effective.

[Brief explanation of the drawing]

FIG. 1 shows an example of an automatic light control electronic flash device of the present invention. 2 shows the integral characteristic of the light reflected from the subject in the light receiving circuit, and FIG. 3 shows the electric circuit diagram of another embodiment of the automatic light control electronic flash device of the present invention. 4A and 4B show an embodiment of the subject distance display section. 4... Main capacitor, 6... Flash tube,
8... Light emission control circuit, 9... Light receiving circuit, 12...°°° clock pulse generation circuit, 13...
... Counter, 14 ... Arithmetic circuit, 16.
−°° decoder, 16...display section, 17...
...A-D conversion circuit, 18... Arithmetic circuit, 19.
...Film sensitivity setting circuit, 2o...Aperture setting circuit, 21...Arithmetic circuit. Name of agent: Patent attorney Toshio Nakao and one other WA
Figure 1 Figure 2 Figure 1114

Claims (1)

[Claims] a main capacitor; a flash tube that consumes the charging energy of the main capacitor to emit a flash; a light receiving circuit that receives and integrates reflected light from a subject and issues a light emission stop signal when the integrated value reaches a predetermined value; and a light emission control circuit that operates in response to the light emission stop signal and stops the light emission of the flash tube, wherein the automatic light control electronic flash device starts operating in synchronization with the light emission of the flash tube and ends the light emission. An automatic light control electronic flash device comprising a distance display device for displaying a subject distance, comprising means for simultaneously ending operation and measuring the light emission interval of the flash tube, and a display means for displaying the light emission interval.