JPH06347872A - Stroboscope device - Google Patents

Abstract

PURPOSE:To make operation at the time of charging a main capacitor easy and simple and to automatically stop the charging. CONSTITUTION:A power supply switch 22 is on-operated to turn on an oscillation transistor 33. The oscillation transistor 33 constitutes a blocking oscillator together with a transformer 32 and is intermittently/repeatedly turned on and off after being temporarily turned on, to charge the main capacitor 13. The main capacitor 13 is charged up to a normal voltage and further, when a neon tube 34 is lighted, the base potential of the oscillation transistor 33 is raised by the current of the lighting, but negated by counter electromotive force generated on the secondary coil of the transformer 32. When the oscillation transistor 33 is turned off, it is never turned on again and the charging is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strobe device having a self-holding function for a charged state and an automatic cutoff function for charging.

[0002]

2. Description of the Related Art A lens-fitted photo film unit known as "Sharp Run Hi" (trade name) is sold with the film pre-loaded in the unit body that incorporates a simple photo-taking mechanism. It is widely used because it is possible and easy to use. Some of the lens-fitted film units have a built-in strobe device that allows you to shoot indoors or at night, such as "Snap Shot Flash" (brand name).

The lens-fitted film unit is premised on being supplied at a low price, and is not structured so that the film built in the unit body or the battery for the strobe device can be replaced. With regard to the strobe device, one AA battery is used to cover stroboscopic photography for one film. Therefore, to avoid wasting the battery uselessly, for example, a method in which the main capacitor for the flash is continuously charged by pressing the push-type power switch or when the slide-type switch lever is operated to the on position. Only the charging is continued.

However, the former one of the above-mentioned two methods is required until the charging of the main capacitor is completed.
It is necessary to keep the power switch pressed, which is a problem in terms of operability. On the other hand, in the latter method, if the switch lever is forgotten to be returned to the off position, the charging is continued, which is disadvantageous in preventing the dry battery from being consumed.

In order to solve these problems, the actual Kaihei 3
In the strobe device described in Japanese Patent Laid-Open No. -65129, charging is started when the operation switch is pressed, and thereafter, until a predetermined time required to charge the main capacitor to a specified voltage elapses, a finger is released from the operation switch. The main capacitor continues to be charged even if it is released. According to this, charging is continued only by pressing the operation switch once, and the charging is automatically stopped after a predetermined time elapses, so that the operability is improved and the wasteful consumption of the dry battery is prevented. You will be able to do that.

[0006]

However, in the strobe device described in the above publication, charging is performed from the time when charging is started until a predetermined time elapses. It depends on the degree of consumption. Then, when the dry battery is exhausted, the main capacitor may not be charged to the specified voltage. In order to avoid this, the predetermined time may be set longer, but if the dry battery is in a new state, it will be uselessly continued to be charged, which is not efficient.

The present invention has been made to solve the above-mentioned drawbacks. The operation of charging the main capacitor is simple, the charging can be stopped at an appropriate timing, and the number of circuit components can be saved as much as possible. It is an object of the present invention to provide a strobe device that can be manufactured at low cost.

[0008]

In order to achieve the above-mentioned object, the present invention is to turn on the switching element for oscillation by an external operation switch to start charging, and after the completion of charging the main capacitor, display the completion of charging. By using the lighting current when the neon tube is lit, the switching element for oscillation is turned off to cut off the charge to the main capacitor. Further, as described in claim 2, the charging may be stopped by stopping the operation of the oscillation switching element after a predetermined time elapses from the lighting time of the neon tube.

[0009]

EXAMPLE FIG. 6 is an exploded view of a unit main body, which is a main part of a lens-fitted photo film unit. The lens-fitted film unit has a cartridge and a film previously incorporated therein during the assembly process of the unit body, and the outer surface of the unit body is further covered with a paper box as an exterior. Since an opening is formed in a required portion of the paper box necessary for a shooting operation, it is possible to shoot while the paper box is covered.

As shown in the figure, the unit main body is composed of a main body portion 2, an exposure unit 3, a strobe device 4, a front cover 5 and a rear cover 6. The main body 2 is integrally provided with a patrone chamber 8 for accommodating a patrone, a film chamber 9 for accommodating a roll-shaped film drawn from the patrone, and a dark box part 10. A winding dial 11 is attached to the upper portion of the cartridge chamber 8, and by rotating the winding dial 11, the spool of the cartridge can be rotated to wind the film.

The exposure unit 3 is coupled to the front surface of the dark box portion 10 by hooking. The exposure unit 3 is equipped with a taking lens, a shutter mechanism, a stepping mechanism for a counter disk, and a winding stop mechanism, as well as an objective lens and an eyepiece lens that form a finder optical system.
It is also possible to remove the exposure unit 3 from the main body 2 when disassembling the lens-fitted film unit that has been used and collected, and reuse the unit that has passed the function inspection.

A strobe device 4 is further attached to the main body portion 2 by hooking. The strobe device 4 includes a circuit board 18 to which circuit components such as a main capacitor 13, an electrode plate 15, and a synchro contact piece 16 are attached, a light emitting portion 19 in which a strobe discharge tube is incorporated and which is attached to the circuit board 18. Dry battery 2 fitted in the electrode plate 15
0 (rated output voltage 1.5 V), one end is held by the main body 2 and the other end is the switch contact pieces 21a, 21b of the circuit board 18.
And a power switch 22 that contacts the.

After the exposure unit 3 and the strobe device 4 are assembled, the front cover 5 is hooked to the main body 2. On the front surface of the front cover 5, an opening for exposing the taking lens and the light emitting portion 19 of the strobe device 4 and an operation button 24 which is pressed when the power switch 22 is brought into contact with the switch contact pieces 21a and 21b are provided. A shutter button 25 and a counter display window are provided on the upper surface.

After the front cover 5 is attached to the main body 2, the cartridge and the film are loaded in the cartridge chamber 8 and the film chamber 9, respectively, and the rear cover 6 is hooked to the main body 2. Then, the assembly of the unit main body is completed by covering the bottom surfaces of the cartridge chamber 8 and the film chamber 9 with a pair of bottom lid portions that are integrally formed with the rear cover 6 so as to be bendable.

FIG. 1 shows a circuit configuration used in the strobe device 4. This strobe circuit has a transformer 32 in which the first and second coils 30a and 30b on the primary side and a secondary coil 31 are connected by a core, and a base terminal at a connection point between the second coil 30b and the secondary coil 31. A blocking oscillator including the connected oscillation transistor 33 is provided. Then, when the blocking oscillator is oscillated, the main capacitor 13 is charged by the current flowing through the secondary coil 31 of the transformer 32.

On the secondary side, a neon tube 3 for indicating the completion of charging is displayed.
4, a trigger capacitor 35, a trigger coil 36, and a strobe discharge tube 37 are connected. Trigger capacitor 35
Is charged to the neon tube lighting voltage after the main capacitor 13 reaches the specified voltage for proper flash emission,
The neon tube 34 is turned on. As a result, when the voltage of the trigger capacitor 35 drops, the neon tube 34 is turned off,
When the trigger capacitor 35 is charged to the lighting voltage again, the neon tube 34 lights up, and as a result, the neon tube 34 starts to blink after the main capacitor 13 is completely charged.

The electric charge of the trigger capacitor 35 is discharged at a moment when the synchronizing contact piece 16 is turned on. The discharge current is boosted through the trigger coil 36, and the trigger electrode 3
A high voltage pulse appears at 8. As a result, the strobe discharge tube 37 is triggered, and the electric charge stored in the main capacitor 13 is discharged through the strobe discharge tube 37, and strobe light emission can be obtained.

The second coil 30b on the primary side and the secondary coil 3
Between the connection point with 1 and the ground, the oscillation transistor 3
A resistor 40 is connected as a charge stopping means for cutting off the switch 3. The resistor 40 lowers the base potential of the oscillation transistor 33 by the lighting current when the neon tube 34 is turned on, and turns off the oscillation transistor 33.
Therefore, in this circuit, charging of the main capacitor 13 and charging of the trigger capacitor 35 are completed, and the neo tube 34 is
When is lit, charging is automatically stopped.

The operation of the strobe device 4 will be described. If you intend to use flash photography, press the operation button 24
Push in. As a result, when the power switch 22 is turned on, a base current flows through the oscillation transistor 33, the oscillation transistor 33 is turned on, and a collector current flows through the first coil 30a. As a result, a large current flows in the secondary coil 31 according to the winding ratio, and the main capacitor 13 is charged by this current. When the current of the secondary coil 31 increases, the base current also increases (positive feedback), and accordingly, the collector current also rapidly increases and the oscillation transistor 33 enters an oscillating state.

When the collector current flowing through the primary coil 30a saturates and its increase ceases, no current flows through the secondary coil 31, the oscillation transistor 33 is turned off, and the collector current sharply decreases. When the collector current sharply decreases, a counter electromotive force is generated in the secondary coil 31 so that the base current flows again in the oscillation transistor 33, so that the oscillation transistor 33 is turned on and becomes in the oscillation state again. By repeating this, the main capacitor 1
3 is charged to a specified voltage that allows the strobe discharge tube 37 to emit light with an appropriate amount of light. Therefore, even if the power switch 22 is not pressed continuously, charging is continuously performed.

After the main capacitor 13 is charged to the specified voltage, the neon tube 34 is turned on when the trigger capacitor 35 is charged to the lighting voltage of the neon tube 34. The lighting current of the neon tube 34 flows through the resistor 40 through the secondary coil 31 and acts to raise the base potential of the oscillation transistor 33. However, when the oscillation transistor 33 is turned off and the collector current sharply decreases, the secondary current increases. The counter electromotive force induced in the coil 31 acts in a direction to cancel it. Therefore, if the oscillation transistor 33 is turned off while the neon tube 34 is lit, the oscillation transistor 33 is not turned on again, and the charging is automatically stopped.

When the neon tube 34 is turned on after the charging is stopped, the electric charge accumulated in the trigger capacitor 35 is slightly consumed, and the terminal voltage of the trigger capacitor 35 becomes low. This is immediately compensated by the main capacitor 13. Be seen. Therefore, even after charging has stopped
Unless the main capacitor 13 becomes lower than the specified voltage, the neon tube 34 blinks to indicate that stroboscopic photography is possible. When the neon tube 34 is turned off, the operation button 24 may be pressed again to perform charging.

When the shutter button 25 of the lens-fitted film unit is pressed, the shutter blades incorporated in the exposure unit 3 open and close. The synchro contact piece 16 is turned on when the shutter blades are fully opened. As a result, the trigger capacitor 35 is discharged, and the trigger electrode 3 is discharged by the discharge current.
High voltage occurs at 8. Then, the internal resistance of the strobe discharge tube 37 is lowered, and the electric charge stored in the main capacitor 13 is discharged in the tube to obtain stroboscopic light emission.

As described above, the primary side of the boosting transformer 32 is connected to the collector of the oscillation transistor 33.
By providing the coil 30a and the second coil 30b connected to the base and turning on the power switch 22 provided between the power supply and the second coil 30b, the booster circuit can be operated in a self-propelled manner, Power switch 22 during charging
There is no need to keep pressing. Further, since the oscillation transistor 33 is turned off by using the current when the neon tube 34 is turned on to stop the charging, the main capacitor 13 can always be charged to the specified voltage or more regardless of the consumption of the dry battery 20. . Moreover, in this embodiment, the number of circuit components used is the same as that of the conventional stroboscopic device of "Sharp Run Flash", and the above-mentioned function can be obtained without increasing the cost.

FIG. 2 shows another embodiment of the present invention. In this embodiment, the lighting current of the neon tube 34 is charged by the capacitor 42 via the resistor 41, and the transistor 43 is turned on when the charging voltage reaches a predetermined level. When the transistor 43 is turned on, the base current does not flow in the oscillation transistor 33, so that the oscillation transistor 33 is maintained in the off state and the charging is stopped. That is, in this embodiment, the timer composed of the resistor 41 and the capacitor 42 is used as the charging stopping means, and the neon tube 34 is used.
The charging is stopped when the timer completes the counting of the predetermined time from the time when is turned on.

In the embodiment shown in FIG. 3, in addition to the circuit shown in FIG.
The emitter terminal and the collector terminal of 5 are connected in parallel, and the base terminal is connected to the first coil 30a via the capacitor 46. When the power switch 22 is turned on, the oscillation transistor 33 is turned on and a collector current flows, the capacitor 46 is charged, and the transistor 45 is maintained in the on state. Therefore, thereafter, even if the power switch 22 is turned off, the base potential of the oscillation transistor 33 can be increased, the collector current during oscillation can be increased, and the main capacitor 13 can be charged quickly.

In the embodiment shown in FIG. 4, a transistor 48 is provided between the dry battery 20 and the base of the oscillation transistor 33. When the oscillation transistor 33 is turned on by turning on the power switch 22, the transistor 48 is turned on, and the oscillation transistor 33 is forward biased. Therefore, the collector current of the transistor 48 is supplied as the base current of the oscillation transistor 33, and the transformer 32 can efficiently perform boosting. As a result, dry battery 2 with a rating of 1.5V
Even when 0 is consumed up to about 1.2 V, the main capacitor 13 can be quickly charged. In addition,
In this example, the FET 49 is used to cut off the oscillation transistor 33 when the neon tube 34 is turned on and a certain time has elapsed, and the lighting current of the neon tube 34 flows through the diode 50. It is possible to cut off the oscillation transistor 33 at an appropriate timing to stop charging without being affected by noise.

The embodiment shown in FIG. 5 is an example in which the charging is stopped by turning off the transistor 48 shown in FIG. 4 when the neon tube 34 is turned on. A FET 52 is connected between the base and the emitter of the transistor 48, and by turning on the FET 52, the transistor 48 is turned off and power supply to the oscillation transistor 33 is cut off. When the neon tube 34 lights up,
The lighting current charges the capacitors 42 and 53,
When these terminal voltages reach a certain level, FET5
2 turns on and the oscillation transistor 33 turns off. In addition,
The switch 54 is turned on together with the synchronizing contact piece 16 to discharge the capacitors 42 and 53. In this embodiment, even if the dry battery is exhausted, the main capacitor 13 can be charged more stably and quickly, and the timing for stopping the charging can be kept stable.

The present invention has been described above with reference to the illustrated embodiments, but the strobe device of the present invention is not limited to being incorporated in a lens-fitted film unit, but can also be used in a strobe device incorporated in a general camera. You can

[0030]

As described above, according to the strobe device of the present invention, charging is automatically continued by turning on an externally operated switch, and further, after the main capacitor is charged to a specified voltage, Charging operation is simple because the charging of the main capacitor is automatically stopped by using the lighting current when the neon tube is lit, and when the charging is completed, the main capacitor does not depend on the degree of power consumption. Is charged to the proper level, you can always take stable flash photography. In addition, the number of circuit components is the same as that of the conventional strobe device, or the number of circuit components is small even if the number is increased, so that it can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram showing another embodiment of the present invention.

FIG. 3 is a circuit diagram showing still another embodiment of the present invention.

FIG. 4 is a circuit diagram showing another embodiment of the present invention.

FIG. 5 is a circuit diagram showing another embodiment of the present invention.

FIG. 6 is an exploded perspective view of a unit body incorporating the device of the present invention.

[Explanation of symbols]

 4 Strobe device 13 Main capacitor 16 Synchronous contact piece 22 Power switch 32 Transformer 33 Oscillation transistor 34 Neon tube 35 Trigger capacitor 37 Strobe discharge tube

Claims (2)

[Claims] 1. A strobe device that lights a neon tube to indicate that charging is completed after the main capacitor has been charged to a specified voltage, and is turned on by operating an external operation switch, and the main capacitor is turned on via a step-up transformer. 2. A strobe device, comprising: an oscillation switching element for charging the charging device, and a charging stop means for detecting a lighting current of a neon tube to turn off the oscillation switching element to cut off the charging of the main capacitor. 2. The charging stop means includes a timer for charging a lighting current of a neon tube to clock a fixed time, and turning off the oscillation switching element in response to completion of timing of the timer. The strobe device according to claim 1.