JPH04104237A - Electronic flash device - Google Patents

Abstract

PURPOSE:To take a photograph in which facial expression is natural and to reduce a red-eye phenomenon by providing plural discharge tubes, installing a lead trigger circuit and a delay trigger circuit and emitting light at specified intervals while a shutter is opened. CONSTITUTION:A switch part 6 selects whether 1st and 2nd light emission parts 2 and 8 are allowed to simultaneously emit light by operating the shutter once or they are allowed to separately emit the light. In the case that the switch part 6 is connected to the lead trigger circuit 5a and the delay trigger circuit 5b sides, a lead trigger pulse is generated from the trigger circuit part of the circuit 5a and the 1st light emission part 2 emits the light when a camera synchro flash switch 7 is closed. Then, the circuit 5b generates the delay trigger pulse and the 2nd light emission part 8 emits the light. At such a time, the shutter is opened until the 2nd light emission part 8 emits the light since the delay trigger pulse is generated. Thus, the photograph in which the facial expression is natural is taken and the red-eye phenomenon is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to electronic flash devices used in photography.

2. Description of the Related Art In recent years, with the spread of cameras, inter-eyelid light emitting devices called electronic flash devices (or strobe devices) have come into widespread use. A conventional electronic flash device will be described below with reference to the drawings.

FIG. 5 is a block diagram of a conventional electronic flash device. A high voltage is supplied from a power supply circuit 1 to cause the xenon discharge tube of the light emitting section 2 to emit light. The trigger circuit 4 is a circuit that drives the light emitting unit to emit light, and the light emission stop circuit 3 forcibly stops the light emission of the xenon discharge tube of the light emitting unit 2, and the 'F-Th' 1 circuit automatically adjusts the exposure amount. An automatic electronic flash device with an automatic circuit that adjusts automatically or an electronic flash device with a light output adjustment function (one that can change the guide number)
This is not the case with electronic flash devices, which have a manual function that keeps the amount of light constant. camera synchro switch 7
is closed in response to camera shutter operation.

The operation of the conventional electronic flash device having the above configuration will be explained below. When the camera synchro switch 7 is mechanically or electronically turned on for a moment in response to the shutter operation of the camera, the trigger circuit 4 sends a trigger pulse to the light emitting unit 2. is given, the xenon discharge tube of the light emitting unit 2 starts discharging, emits a flash of light and emits a predetermined amount of light, and then stops emitting light when a stop signal from the light emission stop circuit 3 arrives. That is, in the conventional electronic flash device, the light is emitted only once while the shutter is closed for one time.

There are multi-electronic flash devices for professional and special photography, but they are expensive, heavy, difficult to use, and lack versatility.

Problems to be Solved by the Invention Ordinary electronic flash devices emit strong light instantaneously, making it very dazzling.In dark places where you want to take photos of natural facial expressions, the pupils of your pupils are dilated. When light enters the eye, the light reflects inside the eyeball and returns to the camera, resulting in a red-colored image, also known as pink eye. This problem is especially likely to occur when cameras have electronic flash devices built into them, and the distance between the light source and the lens is small.

Furthermore, as described above, when an electronic flash device is built into a camera, the amount of light emitted is insufficient, which tends to result in underexposure. In particular, many modern cameras use zoom lenses (at the telephoto end, the lenses are dark and require a large amount of light output).

It is an object of the present invention to provide an electronic flash device that solves many of the problems of the prior art described above.

Means for Solving the Problems In order to achieve the above object, the present invention includes a plurality of light emitting sections, and includes a preceding light emission trigger means and a delayed light emission trigger means, and a delayed light emission trigger for the operation of the preceding light emission trigger means. The device is set to emit light at a predetermined interval while the shutter is open by allowing a predetermined time for the device to operate, and the delayed light emission trigger is set to emit light at a predetermined interval while the shutter is open. By having a variable means that changes a predetermined time until the means operates, it is possible to arbitrarily set the light emission interval, and the light emission amount of a plurality of discharge tubes can be different from each other, and furthermore, it is possible to have a plurality of discharge tubes and lenses. It has a configuration such that the distances between the two are set to be different from each other.

Effects According to the present invention, with the above structure, by emitting light multiple times with an arbitrary time delay following the first light emitted by one shutter operation, it is possible to reduce glare and to photograph natural facial expressions. Prevent the occurrence of red eye phenomenon. At this time,
The light that is emitted after the first light is emitted by the delay trigger circuit can be set to any desired delay time, and the intensity of the light can be arbitrarily combined to reduce the glare of the light emitted by the electronic flash device. and prevent red eye phenomenon. Furthermore, by causing a plurality of light emitting units to emit light at the same time based on the photographer's intention, the amount of light emitted becomes larger, and even with the same aperture and film sensitivity, it is possible to photograph a farther distance.

Also, shifting the distance of each light emitting part from the lens can also help prevent the red eye phenomenon.

Embodiment An electronic flash device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an electronic flash device according to an embodiment of the present invention. Components having the same functions as those of the conventional example shown in FIG.

The switch section 6 can cause the first light emitting section 2 and the second light emitting section 8 to emit light at the same time using the trigger circuit 4 which is a light emission triggering means by one shutter operation, or by using the preceding trigger circuit which is a preceding light emission triggering means. 5a and a delay trigger circuit 5b serving as delayed light emission trigger means.
This is a switch for selecting whether to cause the and second light emitting section 8 to emit light separately. In contrast to the advance trigger circuit 5a, the delay trigger circuit 5b has variable means (not shown) for freely varying the delay time of light emission.

The operation of the electronic flash device having the above configuration will be explained below. A high voltage sufficient to cause the xenon discharge tubes of the first light emitting section 2 and the second light emitting section 8 to emit light is applied from the power supply circuit 1 to the capacitor (see Fig. (not shown) and is applied.

When the switch section 6 is connected to the trigger circuit 4,
When the camera synchronization switch 7 is mechanically or electrically closed, a trigger pulse is applied from the trigger circuit 4 to the first light emitting section 2 and the second light emitting section 8, and the first light emitting section 2 and the second light emitting section 8 are activated. They emit light at the same time. Next, a case will be described in which the switch section 6 is connected to the advance trigger circuit 5a/delay trigger circuit 5b side. This state is an important point of the present invention.

When the camera synchronization switch 7 is mechanically or electrically closed, a preceding trigger pulse is emitted from the trigger circuit portion of the preceding trigger circuit 5a, and the first light emitting section 2 emits light. After a predetermined period of time has passed since this inquiry, the delay trigger circuit 5b generates a delay trigger pulse, and the second light emitting section 8 emits light. At this time, the shutter needs to remain open until the delayed trigger pulse is generated and the second light emitting section 8 emits light. Furthermore, by changing the capacitance of a capacitor (not shown), the combination of light amounts of the first light emitting section 2 and the second light emitting section 8 can be arbitrarily changed. Changing the distance between each light emitting section and the lens has a remarkable effect on preventing the aforementioned red-eye phenomenon. The delay time of the delay trigger circuit 5 can be freely set by a variable means, and it is possible to set the most effective delay time based on the shooting intention.

FIG. 2 shows a specific circuit diagram of an embodiment of the electronic flash device of the present invention, and its structure and operation will be explained below.

In FIG. 2, when the power switch SWI is turned on, the oscillation transistor Tr1. Trl bias resistor R1,
R2 and the oscillation transformer T1 (: Therefore, the DC voltage of the battery B is converted to AC by the converter circuit configured by the oscillation transformer T1, and then boosted by the oscillation transformer T1, rectified by the high-voltage rectifier diode D1, and then connected to the main capacitor C1. At the same time, the main capacitor C4 is charged with the polarity shown in the figure through the diode D2.The main capacitor C4 is charged with the polarity shown in the figure.
When the voltage across the battery 1 reaches the lighting voltage of the neon lamp Nel, the neon lamp Nel lights up to indicate that charging is complete.

R23 is a current limiting resistor for the neon lamp Nel.

The voltage across the main capacitor C4 is the neon lamp Ne2
When the lighting voltage reaches , the neon lamp Ne2 lights up to notify that the main capacitor C4 has been charged. R11 is a current limiting resistor for the neon lamp Ne2.

At this time, the trigger circuit stabilizing resistor R7 of the first light emitting section
Through this, charges are also stored in the trigger capacitor C3 with the polarity shown in the figure. Thyristor 5CRI control transistor T
The voltage divided by the resistors R3 and R5 passes through the base resistor R4 and becomes conductive in the forward direction, collector current flows through the collector resistor R6, and the collector of Tr2 is at ground potential, causing the trigger. Thyristor SCR1
is non-conductive, and the xenon discharge tube Xel does not emit light.

On the other hand, when the main capacitor C1 is charged, charges are also stored in the trigger capacitor C6 with the polarity shown in the figure via the trigger circuit stabilizing resistor R9 of the second light emitting section. At this time, the thyristor 5CR2 is also non-conductive, and the xenon discharge tube Xe2 also does not emit light.

Now that the preparations for emitting light have been completed, the next step is to move on to the camera 7.
Discharge tube 7 lights up, i#ka, yuzuyu, 1.

First, a case where the light emitting state changeover switch SW2 is connected to the a'' terminal, that is, a case where light is emitted multiple times will be described.

When the open flash switch SW3 is closed or the camera synchro switch (not shown) connected to the shoe H8I is closed, the base potential of Tr2 becomes the same potential as the ground (emitter), Tr2 becomes non-conductive, and the collector The potential increases and thyristor 5CRI becomes conductive. R
8 is a gate resistance. Due to the conduction of 5CRI, the charge stored in 03 is discharged through the diode D7, and a high trigger voltage is induced on the secondary side of the trigger transformer T2 due to the voltage change on the primary side of the trigger transformer T2. This voltage is applied to the trigger electrode of the xenon discharge tube Xel, and the xenon discharge tube Xel starts discharging and emits a flash of light. Also, when the open flash switch SW3 closes or the camera synchro switch (not shown) closes, the transistor Tr3
The base and emitter are grounded, and as the base potential drops, the transistor Tr3 becomes non-conductive, and the collector potential instantly becomes plus Vcc. That is, it becomes Hl level (hereinafter abbreviated as rH). Since the input of inverter IN4 becomes rH, its output becomes L.
O (hereinafter abbreviated as rl).

Figure 3 shows waveform diagrams of each part. In the figure, A shows the state (terminal voltage) of a camera synchro switch (not shown), B shows the collector voltage waveform of the transistor Tr3, and C shows the output waveform of the inverter IN4. On the other hand, when the output of inverter IN4 becomes rl, a monostable multivibrator (hereinafter abbreviated as MM) consisting of capacitor C7, resistors R14, R15, NAND3, NAND4, C8 and vRl starts operating. Since the output of this MM is inverted when the input changes from "rH" to "L", the output waveform is shown in D in FIG. NA
When the output of ND4 changes from -“l(” to “L”), the next stage MM (C9, R16, R17, NAND5, NAN
(consisting of D6, CIO and VH2). E in FIG. 3 is its output state diagram. NAND4
The output of NANDI becomes the input, and NANDI and NAND2 form a set/reset flip-flop (hereinafter abbreviated as R-3FF), so the output of NANDI becomes rH.
become. The output of NANDl becomes the gate input of 5CR3, and 5CR3 becomes conductive, so that the charge of the main capacitor C4 is supplied to the xenon discharge tube. R20 is a gate resistance.

This completed preparations for the xenon discharge tube Xe2 to discharge.

Inverter IN+/NAND4 output/NAND
The output of 6 is added as the input of N0R2 to obtain tI of FIG. This signal is sent to R-8 via inverter INI.
It is supplied as a reset signal for NAND2 of the FF.

This will cause thyristor 5CR3 to close the shutter, or
When the open flash switch SW3 is closed, it is non-conducting and prevents the main capacitor 04 from discharging when the xenon discharge tube Xel emits light. Third
11 in the figure is the gate signal NA of thyristor 5CR3.
The waveform of the output of NDl is shown.

The light emission from the second arc tube Xe2 is caused by the thyristor 5CRI being made conductive by the output of NOR1 reaching the I level.
The charge stored in C6 is discharged through diode D8, and a high trigger voltage is induced on the secondary side of trigger transformer T3 due to the voltage change on the primary side. This voltage is applied to the trigger electrode of the xenon discharge tube Xe2, and the xenon discharge tube Xe2 starts discharging and emits a flash of light.

Next, the operation of the switch section of the means for switching between causing the xenon discharge tubes Xe1 and Xe2 to emit light with a predetermined time difference or to emit light simultaneously will be described.

When the light emitting state changeover switch SW2 is connected to the "a" side, the output of the inverter IN4 is input to the NAND8 through IN2. Since one input of NAND8 is grounded by SW2, the output of NAND8 is “H”.
J, the output of NAND6 of MM2 is IN to NAND7.
It is input to NAND7 via S, and one NAN
Since the input of D7 is connected to plus Vcc via resistor R18, the same waveform as the output of NAND6 is output. N0R
1, the output of NAND7, which is the inverted signal of NAND6, is inputted to one side, and the output "H" of NAND8 is inputted to the other side, so the inverted output of NAND6 is output as an output, and at the timing G in Figure 3. Emits light. That is, the xenon discharge tubes Xel and Xe2 emit light with a time difference corresponding to the MMI pulse width. In addition, the pulse width of MMI is VRI
It can be changed arbitrarily by

VRI is a specific example of the aforementioned variable means.

When the light emitting state changeover switch SW2 is connected to "b", the NAND6 is connected to one side as the input of the NAND7.
The output of NAND7 is input via INS, and the other is grounded via SW2, and the output of NAND7 is rH,
However, as the input of NAND8, the output of IN4 is connected to one side via IN2 and to +Vcc via R19 on the other side, so the output of NAND8 is the same waveform as the output of N4. The input of N0R1 is "H" as the output of NAND7 on one side, and NA on the other side.
Since the same waveform as the output of IN4 is input as the output of ND8, the waveform of B in FIG. 3 is output as the output of NOR1. At this time, the xenon discharge tube is F in Figure 3.
It emits light like this. Therefore, in this state, the xenon discharge tubes Xel and Xe2 emit light at the same time, and as a result, the amount of light emitted increases.

Note that by setting the capacitances of the main capacitors C1 and C04 to different values based on the intention of photographing, the amount of light emitted by the xenon discharge tubes Xel and Xe2 can be made to have different values in proportion to the capacitances of the main capacitors C1 and C04.

FIG. 4 shows an embodiment of a camera equipped with an electronic flash device of the present invention. In the figure, 10 is the main body, 9 is the lens, 11 is the shutter button, and 2 and 8 are the light emitting parts of the electronic flash device. The light emitting section 8 pops up and is distanced from the lens, thereby making it possible to prevent the aforementioned red-eye phenomenon from occurring.

In addition, in the above description, the number of light emitting parts was explained as two, but if necessary, it may be three or more, and the above-mentioned effect is further enhanced.

Further, the specific circuits including the advance light emission trigger means and the '11 extended light emission trigger means are not limited to those illustrated, and any circuit that achieves the intended purpose may be used.

DETAILED DESCRIPTION OF THE INVENTION As described above, the electronic flash device of the present invention comprises a plurality of discharge tubes, a leading trigger circuit and a delay circuit.
・Installing a rigger circuit to emit light at predetermined intervals while the shutter is open 1' Knee reduces glare, allows for natural facial expressions, and reduces red-eye phenomenon. can. Furthermore, by varying the distances between the plurality of light emitting parts and the lens by t, the results can be further improved.

Note that it is also possible to arbitrarily vary the delay interval between the first light emission and the light emitted after a delay to take pictures under optimal conditions depending on the shutter speed and the like.

It is also possible to change the amount of light that is emitted initially and the amount of light that is emitted after a delay.For example, you can reduce the glare by setting the first light to a low level (so that your eyes get used to it beforehand) and then increasing the light that is emitted after a delay. It is effective enough to

Furthermore, by causing multiple discharge tubes to emit light at the same time, the amount of light increases, making it possible to take electronic flash photography over a greater distance, which is highly effective in practical use.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an electronic flash device according to an embodiment of the present invention, FIG. 2 is a specific circuit diagram of the same device, and FIG. 3 is a diagram of signal waveforms at various parts and state of the xenon discharge tube. FIG. 4 is an external view of the same built-in camera, and FIG. 5 is a block diagram of a conventional example. 2...First light emitting section including a first discharge tube, 4.
...Trigger circuit 5a which is a light emission trigger means
. . . Advance trigger circuit as advance light emission triggering means, 5b . . . Delay trigger circuit as delay trigger means for delaying light emission for a predetermined time, 6 . . .
A switch circuit, which is a selection means for determining whether to emit light from a plurality of light emitting parts simultaneously or at predetermined intervals, 7... Camera synchronization switch inside the camera, 8... - A second light emitting section including a second discharge tube. Name of agent: Patent attorney Haruaki Ogata and two others

Claims (5)

[Claims] (1) An electronic flash device that includes a plurality of light emitting sections, advance light emission trigger means, and delayed light emission trigger means, and is configured to emit light multiple times while the shutter is open. (2) The electronic flash device according to claim 1, further comprising variable means capable of arbitrarily varying the light emission intervals of the plurality of light emitting sections. (3) The electronic flash device according to any one of claims 1 to 2, wherein the plurality of light emitting sections are configured to emit different amounts of light. (4) The electronic flash device according to any one of claims 1 to 3, further comprising a selection means that enables switching between causing the plurality of light emitting sections to emit light simultaneously or causing the plurality of light emitting sections to emit light separately. (5) The electronic flash device according to any one of claims 1 to 4, wherein the distance between the light emitting section and the lens is different from each other.