JPS6193443A - Automatic two-lamp dimming control circuit - Google Patents

Abstract

PURPOSE:To provide the quantity of light correct in total for photographing conditions while selecting the quantity ratio of the light emitted by two light emitting devices by providing a photometric circuit which outputs the 1st output capable of varying the timing for output and the 2nd output corresponding to the quantity of light of the value higher than the 1st output. CONSTITUTION:The output of the 1st comparator circuit 22 of the photometric circuit is emitted when the 1st output level at which the integrated value of an integration capacitor 19 is determined by a variable resistor 20 is attained. The output of the 2nd comparator 24 is emitted when the 2nd output level at which the integrated value is the value optimum for photographing is attained. A synchronizing contact 10 is closed when the shutter of a camera is released. Then the 1st discharge tube 6 discharges electricity and a voltage is generated in a Zener diode 17, by which the operation of the photometric circuit is started. An SCR13 operates when the capacitor 19 attains the 1st output level by receiving the light reflected from the subject. A trigger capacitor 11 is then discharged and the 2nd discharge tube 7 discharges electricity to operate a quench pipe 14 so that the 1st discharge tube 6 stops the discharge. An SCR16 operates when the 2nd output level is attained. The discharge of the tube 7 is then stopped.

Description

[Detailed Description of the Invention] [Object of the Invention] LtjJ! This invention relates to flashlights used for photography, and uses two light emitters to provide the appropriate amount of light for the shooting conditions.
Moreover, the present invention relates to a control circuit that controls the light amount ratio so that it can be arbitrarily set.

[Kugo Katsutobi] Lighting is the most important thing when photographing.When photographing using an artificial light source, it is not possible to obtain a good photograph by simply shining light on the subject from the front.Therefore, professional photographers
For amateurs who use multiple light sources for lighting, it is not possible to use many light emitters, so
Normal - Shooting with only lights. Therefore, it is not possible to take very good photos.

Recently, flashlights that automatically control the amount of light emitted according to the distance to the subject have appeared, which has become more convenient for users of flashlights. However, even in this case, the amount of light emitted is only controlled by a photometry circuit that stops the light emission when the amount of light reaches an appropriate amount for the photographing conditions, and does not control multiple light emission.

It is extremely difficult to cause multiple light emitters to emit light and control the amount of light to an appropriate level. In particular, it is difficult to change the amount of light emitted, that is, the scene ratio.

Conventionally, a device in which two lamps are emitted and the ratio of the amount of light emitted from each lamp is arbitrarily set is known, for example, as shown in Japanese Patent Laid-Open No. 123147/1983.

In the above conventional example, two light emitters each having a photometric circuit are made to emit light in sequence.The first light emitter is made to emit light, and the light is measured by the photometric circuit of the first emitter, and when the light intensity reaches a preset value, The light emission is stopped and the second light emitter is made to emit light using the output from the photometric circuit, and when the photometric circuit of the second light emitter reaches a preset amount of light emitted, the second light emitter starts emitting light. It is designed to stop. Therefore, the light emission ratio of both light emitters can be set arbitrarily.

However, as described above, in the conventional device, the ratio of the amount of light emitted by the two light emitters can be set arbitrarily. However, since each light metering circuit installed in each light emitter measures the light independently, it is not possible to control the total amount of light, and therefore it is not possible to control the overall light amount to be appropriate for the shooting conditions. .

In reality, this cannot be used by ordinary amateur photographers.

Therefore, it is an object of the present invention to provide a control circuit that can cause two lamps to emit light, change the light amount ratio of each as desired, and control the total amount of light to be appropriate for the shooting conditions of the camera. It is something to do.

[Structure of the invention]. According to the present invention, the first light emitter and the second light emitter sequentially emit light in synchronization with the shutter operation of the camera, and
A first output that can receive reflected light from the subject and change the output timing, and a second output level that is higher than the output level of the first output and corresponds to the appropriate amount of light for the shooting conditions. The first output of the photometric circuit causes the first light emitter to stop emitting light and the second light emitter to emit light, and the second output of the photometric circuit causes the second light emitter to emit light. This is characterized by the fact that it stops.

Naturally, the output level of the second output can be changed depending on the photographing conditions.

There is only one photometry circuit, and the first output of the photometry circuit, which has a low output level, stops the first light emitter from emitting light, and at the same time causes the second light emitter to emit light, and the output level is higher than the first output level. Since the second output is output at a level that corresponds to the appropriate amount of light for the conditions, the second light emitter stops emitting light, so the total amount of light emitted from both sources will be the amount of light that is appropriate for the shooting conditions. Therefore, even if the two light emitters are made to emit light separately, the total amount of light can be made appropriate for the photographing conditions. Moreover, since the output level of the first output of the photometric circuit can be changed, the light intensity ratio of the two light emitters can be arbitrarily set, allowing lighting to be performed as desired.

The circuit of the illustrated embodiment is a so-called twin strobe in which two light emitters are housed in one case. A second discharge capacitor 2 is connected to be charged from a power source 3 via a diode 4.5. A first discharge tube 6 is connected in parallel to the second discharge capacitor 1 . A second discharge tube 7 is connected in parallel to the second discharge capacitor 2. The circuit for starting the discharge of the first discharge tube 6 may be exactly the same as the conventional tri-circuit, and consists of a first trigger capacitor 8, a first trigger transformer 9, and a synchro contact 1O. The circuit for starting the discharge of the second discharge tube 7 includes the second Nidriger capacitor 11, the second Nitrigger transformer 12, and 5CR13, and the second discharge tube 7 is operated by the operation of 5CR13. This 5CR13 is for stopping the discharge of the first discharge tube 6, as will be described later.

Therefore, the second discharge tube 7 is started to discharge simultaneously with the discharge stop operation of the first discharge tube 6. The quench tube 14 connected in parallel to the first discharge tube 6 bypasses the electric charge of the second discharge capacitor 1 to stop the discharge of the first discharge tube 1. The 5CR 13 operates the first quench pipe 14. That is, the 5CR 13 operates to discharge the second discharge tube 7 and the first quench tube 14 at the same time. The second quench tube 15 is also used to stop the second discharge tube 7 from discharging, and is activated by 5CR16. The 5CRs 13 and 16 are operated by a photometric circuit shown in FIG.

1 °°"lli@IMI""-'-°"'1°"
A voltage is applied to the Zener diode 17, which generates a Zener voltage by the discharge of '-j 7, and the phototransistor 18 receives the reflected light from the subject and converts it into an electric signal. , a first comparator circuit 22 which has an optical integration circuit including an integrating capacitor 19 and is connected between the integrating capacitor 19 and the sliding piece 21 of the variable resistor 20, the integrating capacitor 19, the resistor 23 and the variable resistor. 20 and a second comparator 24 connected between the two. Variable resistor 25 and resistor 23
and the variable resistor 20 are connected in series, and a voltage is applied from the Zener diode 17.

The output of the first comparator circuit 22 is output when the integrated value of the integrating capacitor 19 reaches the first output level determined by the sliding piece 21 of the variable resistor 20, and the output of the second comparator circuit 2
The output No. 4 is output when the integral value of the integrating capacitor 19 reaches the second output level, which is the optimum value for photographing. 5
CR13 operates with the output of the first comparison circuit 22, and 5CR1
6 is operated by the output of the second comparison circuit 24. The variable resistor 25 is used to simultaneously adjust both the first output level and the second output level to adapt to the photographing conditions, and the variable resistor 20 is used to control the first output level. The first output level can be changed from O to the second output level depending on the position of the sliding piece 21. In other words, it is possible to change the level from a level where the first discharge tube 6 is turned off almost simultaneously with the emission of light to a level where an appropriate exposure value is obtained only by this.

The operation of the illustrated embodiment will be explained below. When the first discharge capacitor 1 and the second discharge capacitor 2 are charged by the power source 3, the light emission is ready. When the shutter of the camera (not shown) is then released, the synchronization contact 10 is closed. The first trigger capacitor 8 is discharged, and the first discharge tube 6 is discharged. This discharge generates a voltage in the Zener diode 17, and the photometry circuit starts operating. Therefore, the reflected light from the subject is received and integrated by the integrating circuit. When the integrating capacitor 19 reaches the first output level, the 5CR 13 operates, operating the quench tube 14, discharging the second Nidriger capacitor 11, and discharging the second discharge tube 7. Quench tube 1
4 causes the first discharge tube 6 to stop discharging. After the object is illuminated by the discharge of the first discharge tube 6, it is further illuminated by the second discharge tube 7. The photometering circuit continues to measure the light, and when it reaches the second output level, it outputs 5CR.
Operate 16. The quench tube 15 is activated by the operation of the 5CR 16, and the discharge of the second discharge tube 7 is stopped.

[Effects of the Invention] As described above, in the present invention, first, the first discharge tube 6 discharges and emits light, stops emitting light at the first output level of the photometry circuit, and the second discharge tube emits light almost simultaneously. 7, the object is further illuminated, and when the second output level is reached, the second discharge tube also stops emitting light. There is only one photometering circuit, and its second output level is output when the appropriate exposure level for photography is reached, so even if the two light emitters are fired separately, the total amount of light will be appropriate. The light emission can be stopped. Furthermore, since the first output level of the photometric circuit is lower than this second output level and can be changed, the timing at which the first light emitter stops emitting light can be changed arbitrarily as desired. , the luminescence seniority ratio of the two light emitters can be set as appropriate. That is, according to the present invention, it is possible to select the light emission ratio between the two light emitters and provide the total amount of light that is appropriate for the photographing conditions.

Therefore, even amateurs can easily enjoy dual light emission.

[Brief explanation of the drawing]

The figures relate to an embodiment of the present invention; FIG. 1 is a circuit diagram excluding a photometric circuit, and FIG. 2 is a circuit diagram of the photometric circuit. l: first discharge capacitor, 2: second discharge capacitor, 6: first discharge tube, 7: second discharge tube, 17: Zener diode, 13.16: scR. 18゛: Phototransistor, 19: Integrating capacitor.

Claims (1)

[Claims] In a control circuit that causes two light emitters to emit light and controls the amount of light emitted by these light emitters to an amount of light appropriate for the camera's shooting conditions, the first light emitter and the second light emitter are sequentially activated in synchronization with the shutter operation of the camera. A first output that emits light, receives reflected light from the subject, and can vary the output level; and a value that is higher than the output level of this first output and corresponds to the appropriate amount of light for the shooting conditions. It has a photometric circuit that outputs a second output at a second output level, and the first output of the photometric circuit stops the first light emitting device that was emitting light in synchronization with the camera shutter, and also stops the second light emitting device. A two-lamp automatic dimming control circuit characterized in that the second light emitter is configured to emit light and to stop the second light emitter from emitting light using the second output of the photometry circuit.