JP2000267160A - Built-in stroboscopic device for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent ignition to hydrogen gas and burning caused by the action of a stroboscopic device by connecting a Zener diode in parallel with a synchro switch and connecting a switching capacitor to the Zener diode. SOLUTION: The Zener diode 96 is connected in parallel with the synchro switch 77 turned on/off interlocked with the actuation of a shutter mechanism. The current of a dry cell is boosted to about 350 V by a transistor 86 and a stepup transformer 87 in a booster part 83. Then, a main capacitor 76 and a trigger capacitor 93 are charged through a diode 88. The charging voltage of a switching capacitor 95 is restricted to 5 V being equal to or under Zener voltage. The current of about 5 V being the charging voltage of the capacitor 95 flows to the switch 77, and is set as a gate current so as to turn on a thyristor 97 to which the capacitor 93 is connected. Thus, sparks coo not fly between the armatures of the switch 77.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a built-in flash device for a camera.

[0002]

2. Description of the Related Art A lens-equipped film unit, which is a kind of a simple camera provided with a simple photographing mechanism and pre-loaded with an unexposed photographic film and a patrone, is widely used because it is inexpensive and easy. I have. This lens-fitted film unit is available in a variety of products depending on the shooting purpose and application.In order to enable underwater shooting, the lens-fitted film unit is mounted on a waterproof case with a watertight structure. There are various types of film units with a waterproof lens that can be used for shooting operation from outside the waterproof case.

[0003]

The above-mentioned film unit with a lens is generally equipped with a built-in flash device. The dry battery used in such a flash device uses hydrogen gas during the use process. May be released. When such a flammable gas is generated, particularly in a film unit with a lens housed in a sealed container such as a waterproof case, the flammable gas is accumulated inside the case.

On the other hand, when performing flash photography, a high voltage current from a trigger capacitor flows through a contact of a trigger switch that is turned on and off in conjunction with a shutter operation, and a spark may be generated at the contact. . Then, there is a possibility that the spark ignites the hydrogen gas staying inside the waterproof case or the like, and the hydrogen gas burns. Therefore, a countermeasure is desired.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a built-in flash device for a camera which prevents ignition and burning of combustible gas such as hydrogen by operation of the flash device. .

[0006]

In order to solve the above-mentioned problems, the present invention provides a booster circuit for boosting a power supply voltage and a secondary current connected to a secondary side of the booster circuit. A built-in strobe device for a camera comprising: a main capacitor charged by a camera; a trigger capacitor for starting the discharge of the main capacitor; a synchro switch for turning on and off in conjunction with a shutter operation of the camera; A Zener diode is connected in parallel with the synchro switch, and a switching capacitor is connected to the Zener diode to limit the charging voltage of the switching capacitor to a Zener voltage or less, a thyristor is connected in series to the trigger capacitor, and a gate of the thyristor is connected. Connected to the switching capacitor, Serial discharge current of the switching capacitor is discharged by turning on the synchronous switch input to the gate of the thyristor, it is intended to discharge the trigger capacitor by the gate input of the thyristor.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described.
An embodiment in which the built-in flash device of the present invention is incorporated in a film unit with a waterproof lens, which is a kind of a simple camera, will be described. FIG. 2 is a perspective view showing the external shape of the film unit 2 with a waterproof lens.
Is an exploded perspective view thereof. The waterproof lens-fitted film unit 2 is composed of a lens-fitted film unit 3 that forms a camera body and a waterproof case 4 that houses the lens-fitted film unit 3.

A wind-up knob 6 for winding up a photographed photo film is attached to the upper surface of the waterproof case 4. On the front surface of the waterproof case 4, a shutter lever 5 for performing shutter release is attached.
Further, there is provided an exposing part 9 which is a transparent part for exposing the photographing lens 7 and the object side finder window 8 of the lens-fitted film unit 3 to the outside.

Further, a light-emitting portion 71 of a strobe device 70 is exposed through a transparent portion on the front surface of the waterproof case 4, and a charge switch 7 of the strobe device 70 is provided at a lower portion of the front surface.
A switch operation member 73 for operating the waterproof case 2 from the outer surface of the waterproof case 4 is formed.

As shown in FIG. 3, the lens-fitted film unit 3 used in the waterproof lens-fitted film unit 2 has a photographic lens 7 on the front surface, an object-side finder window 8,
An opening 11 for a shutter lever is formed, and a light emitting section 71 and a charging switch 72 of the strobe device 70 are exposed. The upper surface is provided with a winding knob opening 12 and a counter window 13 for displaying the remaining number of shootable images.
On the back, the eyepiece side finder window 14 (see FIG. 4)
Is provided.

As shown in an exploded view of FIG. 4, the lens-fitted film unit 3 has a main body base 19 in which a cartridge chamber 17 in which an unused photographic film cartridge 16 is loaded and a film chamber 18 are integrally formed. An exposure unit 22 mounted on the front side of the main body base 19 and incorporating the photographic lens 7, a finder optical system 20, a shutter mechanism 21, a film winding mechanism, a film counter mechanism, and the like; And a front cover 23 and a rear cover 24 that cover the front and back sides of the main body base 19.

On the upper part of the cartridge chamber 17 of the main body base 19, a hoisting dial 28 that engages with the spool 27 of the cartridge main body 26 is rotatably mounted. An engagement hole 29 is formed on the upper surface of the winding dial 28 to engage the winding knob 6 attached to the waterproof case 4.
3 and is exposed to the outside through an opening 12 formed in the same. In the front cover of a normal lens-fitted film unit, a shutter button is provided at the position of the opening 12. The shutter mechanism 21 of the exposure unit 22 is exposed to the outside by a shutter lever opening 11 formed on the front surface of the front cover 23.

The lens-fitted film unit 3 is almost the same as a normal lens-fitted film unit, but a dedicated unit is used for the front cover 23 and the winding dial 28.

As shown in FIG. 3, the waterproof case 4 is placed over the lens-fitted film unit 3 from the front side.
A front case member 32 covering the bottom surface and both side surfaces, and a film unit 3 with a lens so as to cover the front case member 32.
The rear case member 33 is assembled to the front case member 32 from behind, and a waterproof cover 34 is placed on the outside of the front case member 32.

The front case member 32 is formed of a transparent plastic, and has a front surface provided with an exposing portion 9 for exposing the photographing lens 7 and the object side finder window 8 of the lens-fitted film unit 3 to the outside. ing. An opening 37 for accommodating the lens-fitted film unit 3 is formed on the back side of the front case member 32.
On the outer periphery of the opening 37, a ridge 38 is integrally formed over the entire periphery.

On the front surface of the front case member 32, a column-shaped boss 40 to which the shutter lever 5 is swingably attached is provided upright toward the front side. This boss 4
A hole 41 is formed in the front case member 32 so as to penetrate the inside of the front case member 32, and a small-diameter O-ring 42 is housed in the tip of the hole 41. The O-ring 42 prevents water, dust and the like from entering the waterproof case 4 through the hole 41 of the boss 40.

The shutter lever 5 has a substantially wedge shape, and a shaft 43 which is inserted into the hole 41 of the boss 40 and serves as a swing center of the shutter lever 5 is formed on the back side thereof. After being inserted into the hole 41 of the boss 40, a release lever 44 is attached to the tip of the shaft 43 in the front case member 32.

When the film unit with lens 3 is stored in the front case member 32, the release lever 44 enters the opening 11 formed on the front surface of the front cover 23 and engages with the shutter mechanism 21 of the exposure unit 22. Combine.
Thus, when the shutter lever 5 is swung, the shutter mechanism 21 in the lens-fitted film unit 3 operates. Further, a torsion spring 45 is attached to the outer periphery of the boss 40. The torsion spring 45 urges the shutter lever 5 clockwise in the drawing to always return the shutter lever 5 to the initial position.

In the lower part of the front surface of the front case member 32,
A switch operation member 73 for operating the charge switch 72 of the strobe device 70 from the outer surface of the waterproof case 4 is formed.

On the upper surface of the front case member 32, a column-shaped boss 47 to which the winding knob 6 is rotatably mounted is erected upward. A hole 48 is formed in the boss 47 so as to penetrate the inside of the front case member 32, and a large-diameter O-ring 49 is housed in a tip portion of the hole 48. The O-ring 49 prevents water, dust and the like from entering the waterproof case 4 through the hole of the boss 47.

The winding knob 6 includes a disk-shaped operating portion 51 having an outer periphery formed with finger projections and depressions.
1 and a drive shaft 52 formed on the lower surface. Drive shaft 5
2 is inserted into the hole 48 of the boss 47 and engages with the engagement hole 29 of the winding dial 28 through the opening 12 formed in the front cover 23 of the film unit 3 with lens.

When the winding knob 6 is rotated counterclockwise in the figure, the film unit 3 with lens
The take-up dial 28 is rotated in the same direction, and the photographed film is taken in the cartridge body 26. Although not shown in detail, the outer peripheral surface of the drive shaft 52 is formed with a claw member that is inserted into the hole 48 of the boss 47 and then engages with the inner wall surface of the front case member 32. 6, the front case member 32 does not fall off.

On the lower surface of the hoisting knob 6, a pawl member 54 which operates in conjunction with the rotation of the hoisting knob 6 is swingably mounted. When the winding knob 6 is rotated in the film winding direction in the counterclockwise direction in the drawing, the claw member 54 engages with the teeth formed inside the operation portion 51 of the winding knob 6 to generate a ratchet sound. appear. When the wind-up knob 6 is rotated clockwise in the figure, the wind-up knob 6 meshes with the teeth in the operation unit 51, and prevents the wind-up knob 6 from rotating in the opposite direction.

The waterproof cover 34 is formed of a transparent elastomer which is a polymer substance having rubber-like elasticity.
The strobe light from the light emitting unit 71 is transmitted. The waterproof cover 34 has a similar shape slightly larger than the front case member 32 so as to be tightly covered on the outside of the front case member 32.

An opening 56 for opening the exposing portion 9 formed on the front surface of the front case member 32 and an opening 75 for exposing the switch operating member 73 are formed on the front surface of the waterproof cover 34, respectively. Openings 58 and 59 for penetrating the bosses 40 and 47 of the front case member 32 are formed on the front surface and the upper surface of the waterproof cover 34.

On the back side of the waterproof cover 34, an opening 61 for covering the front case member 32 is formed. The outer periphery of the opening 61 has a ridge 6
2 are integrally formed. The ridge 62 is covered on the outside of the ridge 38 of the front case member 32.

The rear case member 33 is made of a transparent plastic so that the object-side finder window 14 can be observed from outside through the rear case member 33. On the outer periphery on the front side of the rear case member 33, a concave portion 64 is formed over the entire circumference, in which a ridge 62 formed in the opening 61 of the waterproof cover 34 and a ridge 38 of the front case member 32 are fitted. I have. The width of the concave portion 64 is
4 is slightly smaller than the ridge 62, so that when the ridge 62 is fitted into the concave portion 64, it is crushed and adheres to the inner wall surface of the concave portion 64, and between the waterproof cover 34 and the rear case member 33. Make sure to waterproof.

On both sides on the front side of the rear case member 33,
Two locked pieces 67 each having a locked hole 66 are provided. These locked pieces 67 are formed by locking claws (not shown) formed on the inner surface of the side surface of the front case member 32.
Is engaged. Thereby, the rear case member 33 is firmly attached to the front case member 32, and the waterproof cover 34
The degree of adhesion between the case and the rear case member 33 increases, and the waterproof case 4
The waterproofness of the is improved.

As shown in FIG. 5, a strobe device 70 of the present invention comprises a main condenser 76, a synchro switch 7
7, a circuit board 81 on which a battery contact piece 78 and the like are attached;
It comprises a light emitting unit 71 having a strobe discharge tube therein, a dry battery 79 serving as a power supply for the strobe device 70, and the like.

Strobe circuit 8 formed on circuit board 81
2, a booster 83 which forms a booster circuit for boosting the voltage of the dry battery 79, and a main capacitor 76, as shown in FIG.
And a charging / light emitting portion 85 including a strobe discharge tube 84 and the like.

The booster 83 includes a dry cell 79 serving as a power supply, an oscillating transistor 86, a resistor 99, and a booster transformer 8.
7, a charge switch 72, a diode 88 and the like. When the charge switch 72 is turned on, the 1.5V voltage of the dry battery 79 is boosted by the booster 83,
A voltage of about 350 V is generated on the secondary side

The charging light emitting section 85 includes the main capacitor 7
6. Strobe discharge tube 92, trigger capacitor 93, transformer 94, synchro switch 77, switching capacitor 95, zener diode 96, thyristor 97,
And a plurality of resistors 98a to 98d.

The main capacitor 76 is connected to the booster 83
The battery is charged with a voltage of about 350 V generated on the next side, and a strobe light is emitted from a strobe discharge tube 92 by discharging.
The trigger capacitor 93 is charged at the same time as the main capacitor 76 is charged, and generates a high voltage current on the secondary side of the transformer 94 by discharging to lower the resistance in the strobe discharge tube 92 and discharge the main capacitor 76. This trigger capacitor 93 is connected via a transformer 94 to the anode and cathode of a thyristor 97 as a switching element.

The sync switch 77 is a shutter mechanism 2
Turns on and off in conjunction with the operation of 1. A zener diode 96 is connected in parallel with the synchro switch 77. The Zener diode 96 has a Zener voltage of 5
A material of about V is used.

The synchro switch 77 and the Zener diode 96 are connected to a switching capacitor 95 charged at a voltage considerably lower than the secondary current. The switching capacitor 95 is charged at the same time as the main capacitor 76 and the trigger capacitor 93 are charged. At this time, since the Zener voltage of the Zener diode 96 is 5 V, the charging voltage of the switching capacitor 95 is limited to 5 V or less.

The gate terminal of the thyristor 97 is connected to the switching capacitor 95. Sync switch 7
When the switch 7 operates, the switching capacitor 95 is discharged and input to the gate terminal of the thyristor 97 as a gate signal. The resistors 98a and 98b have a resistance of about 1 MΩ, and the resistors 98c and 98d have a resistance of about 1 kΩ.

Next, the operation of the lens-equipped film unit provided with the above-described flash device will be described. When performing flash photography using the lens-fitted film unit 3 stored in the waterproof case 4, first,
The winding knob 6 is rotated counterclockwise to set an unexposed photographic film. Then, the switch operation member 73
Press. When the switch operation member 73 is pressed, the charge switch 72 in the circuit diagram of FIG. 1 is turned on.

When the charge switch 72 is turned on, the 1.5 V current of the dry battery 79 is applied to the transistor 8 of the booster 83.
6. The voltage is boosted to about 350 V by the boost transformer 87 or the like.
And, via the diode 88, the main capacitor 7
6, and the trigger capacitor 93 is charged.

Switching capacitor 95 at the time of charging
Is also charged, but this switching capacitor 9
The voltage applied to the Zener diode 96 connected to 5 is 5 V
Is exceeded, a Zener current flows through the Zener diode 96, so that the charging voltage of the switching capacitor 95 is limited to 5V which is equal to or lower than the Zener voltage.

When the photographer confirms the photographing range through the finder optical system 20 and swings the shutter lever 5, the shutter mechanism 21 operates to photograph one frame. At this time, in synchronization with the operation of the shutter mechanism 21, the synchro switch 77 is turned on, the switching capacitor 95 charged to 5 V or less is discharged, and is input to the gate of the thyristor 97 as a gate current.

When the gate of the thyristor 97 is turned on,
The trigger capacitor 9 is turned on between the anode of the thyristor 97 and the assortment and charged to about 350 V.
3 discharges. Then, 4 kV is applied to the secondary side of the transformer 94.
Is generated, and the resistance in the strobe discharge tube 92 decreases. As a result, the main condenser 76 is discharged, and strobe light is emitted from the strobe discharge tube 92 toward the subject, thereby illuminating the subject brightly.

At the time of opening / closing the synchro switch 77 described above, the synchro switch 77 is set to 350 V as in the prior art.
Without directly flowing the discharge current of the trigger capacitor charged to the high voltage, a current of about 5 V, which is the charging voltage of the switching capacitor 95, is flown.
By turning on the thyristor 97 to which the trigger capacitor 93 is connected, no spark is generated between the contacts of the synchro switch 77.

A dry battery 79 serving as a power supply for the strobe device 70
May release hydrogen gas during use.
When such flammable gas is generated, the lens-equipped film unit 3 housed in a container sealed in a waterproof case 4.
In this state, the flammable gas stays inside. However, since a discharge current of about 5 V from the switching capacitor 95 is supplied to the synchro switch 77, no spark is generated between the contacts when the synchro switch 77 is operated, and the hydrogen gas remaining inside the waterproof case 4 is not generated. Never ignite. As a result, it is possible to reliably prevent an accident of ignition or burning due to combustible gas during flash photography.

It should be noted that, apart from the above-described embodiment, the generation and combustion of flammable gas is achieved by using a type of dry battery that does not generate flammable gas such as hydrogen for the power source of the built-in flash device. It may be prevented.

In the above-described embodiment, an example is shown in which the built-in flash device for a camera of the present invention is mounted on a film unit with a lens. However, it is needless to say that the present invention can be applied to a normal camera such as a compact camera. It is possible.

[0046]

As described above, according to the present invention,
A booster circuit for boosting a power supply voltage, a main capacitor connected to a secondary side of the booster circuit and charged by a secondary current of the booster circuit, a trigger capacitor for starting discharge of the main capacitor, In a built-in flash device for a camera comprising a synchro switch which is turned on / off in conjunction with a shutter operation and a strobe discharge tube or the like, a zener diode is connected in parallel with the synchro switch and a switching capacitor is connected to the zener diode. Limiting the charging voltage of the switching capacitor to a Zener voltage or less, connecting a thyristor to the trigger capacitor in series and connecting the switching capacitor to the gate of the thyristor,
The discharge current of the switching capacitor discharged by turning on the synchro switch is input to the gate of the thyristor, and the trigger capacitor is discharged by the gate input of the thyristor. It is possible to provide a built-in strobe device for a camera in which ignition and burning of the camera are prevented.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a built-in flash device for a camera according to the present invention.

FIG. 2 is a perspective view showing an appearance of a film unit with a waterproof lens provided with a built-in flash device for a camera according to the present invention.

FIG. 3 is an exploded perspective view of FIG. 2;

FIG. 4 is an exploded perspective view showing the configuration of a film unit with a lens.

FIG. 5 is an external perspective view showing a built-in flash device for a camera according to the present invention.

[Explanation of symbols]

 2 Film unit with waterproof lens 3 Film unit with lens 4 Waterproof case 5 Shutter lever 6 Winding knob 9 Exposed part 70 Strobe device 77 Trigger switch 79 Dry cell 92 Strobe discharge tube 93 Trigger capacitor 95 Low voltage capacitor 97 Thyristor

Claims (1)

[Claims] 1. A booster circuit for boosting a power supply voltage, a main capacitor connected to a secondary side of the booster circuit and charged by a secondary current of the booster circuit, and a trigger for starting discharge of the main capacitor. In a built-in strobe device for a camera comprising a capacitor, a synchro switch which is turned on / off in synchronization with a shutter operation of the camera, and a strobe discharge tube, etc., a zener diode is connected in parallel with the synchro switch and a switching capacitor is connected to the zener diode. To limit the charging voltage of the switching capacitor to a Zener voltage or less, connect a thyristor to the trigger capacitor in series, connect the switching capacitor to the gate of the thyristor, and discharge when the synchro switch is turned on. The switch The discharge current of the grayed capacitor input to the gate of the thyristor, a camera built-in flash apparatus characterized by discharging said trigger capacitor, the gate input of the thyristor.