JPH11183975A - Stroboscopic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain cost rise while improving operability at the time of charging and reducing the consumption of a battery. SOLUTION: A film unit with a lens is provided with an operation lever slid between an on-position and an off-position in order to turn on/off a charge switch 15 for performing the on/off control of charge. The operation lever functions also as an operation member for selecting the propriety of strobe light emission, and when it is at the on-position, a light emission selecting switch 41 is turned on to allow the strobe light emission. An automatic cut circuit 30 stops a booster circuit 20 even though the switch 15 is turned on when the charge voltage of a main capacitor 35 is equal to or above prescribed charge voltage. Thus, even in a state where the switch 15 is turned on, the circuit 20 is intermittently actuated and needless power consumption is reduced. By performing charge completion display by an inexpensive light emitting diode 29 instead of an expensive neon tube, the cost rise associated with the addition of the circuit 30 is restrained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flash unit used for a film unit with a lens and a camera.

[0002]

2. Description of the Related Art Some cameras and film units with lenses have a built-in strobe device, which is convenient for photographing in a dark place or indoors. When performing flash photography,
It is necessary to charge the main capacitor to a specified charging voltage in advance. For this reason, the charge switch is normally turned on prior to flash photography.

For example, a charge switch of a film unit with a lens is a push-type switch which is turned on by pressing an operation button.
There are a slide type that switches between N and OFF, and a type that raises the operation lever to turn it on (hereinafter referred to as a pull-up type). In a flash device using a push type, a charge switch is turned on while the operation button is kept pressed.
The charging switch is turned on once by pressing the operation button and the charging is performed when the charging is set to N (hereinafter, referred to as a continuous pressing type).
Then, immediately after that, the charging is continued even if the pressing is released and turned off, and the charging is automatically stopped when the charging voltage reaches the specified charging voltage (hereinafter, referred to as an automatic charging stop type). In the case of the slide type, the charging O
It is known that N, OFF and the necessity of strobe light emission can be simultaneously selected. In a flash device using a pull-up type charging switch, if the operating lever is raised, the charging switch is turned on and charging is continued.

[0004]

By the way, the strobe device of the continuous pressing type has the simplest mechanism and circuit configuration and is low in manufacturing cost, but the operation button must be pressed until charging is completed, so that the operating button is operated. However, there is a disadvantage that it is bothersome. In addition, in a flash device using a slide-type and pull-up type charge switch, once the charge switch is turned on, charging is continuously performed. There is an advantage that whether or not strobe light emission is performed can be clearly determined. However, on the other hand, charging is continued unless the user operates the operation lever to turn off the charge switch. Therefore, if the charge switch is forgotten to be turned off for a long time, the battery power is consumed and the strobe light cannot be emitted. There is a drawback that the danger of becoming high is increased. The pull-up type charging switch has the effect of calling attention to forget to turn off the charging switch in the state of the operation lever, but the effect is not sufficient.

Also, an automatic charging stop type strobe device is
As described above, once the charging switch is turned ON, charging is continued, and charging is stopped when the charging voltage reaches the specified charging voltage. This improves operability and reduces unnecessary power consumption of the battery. It is effective in eliminating it. However, the number of components has increased due to the suspension of charging, and the manufacturing cost has increased. In addition, there is a characteristic on the circuit that charging starts after the flash is fired.
There was a problem that it was not possible to take a picture without firing the flash.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a strobe device capable of simultaneously improving operability during charging, reducing power consumption, reducing costs, and clarifying strobe light emission. The purpose is to provide.

[0007]

In order to solve the above-mentioned problems, according to the present invention, one of an on position where the charging switch is turned on by an external operation and an off position where the charging switch is turned off by an external operation. An operation member that is selectively switched to a, an auto-cut circuit that stops the booster circuit in response to the charging voltage of the main capacitor reaching a predetermined level, and an operation transformer that is obtained from an oscillation transformer during operation of the booster circuit. A light-emitting diode that lights up when the main capacitor reaches a predetermined charging voltage by applying a voltage that changes proportionally according to the charging voltage of the main capacitor, and indicates that charging has been completed.

According to the present invention, there is provided a strobe light emission selection switch for permitting or inhibiting the discharge of the strobe discharge tube by the main capacitor according to the position of the operation member, and interlocks with the turning off of the charge switch. Discharge is prohibited.

According to a third aspect of the present invention, in the automatic cut circuit, the charging voltage of the main capacitor or a voltage that changes proportionally according to the charging voltage is applied as a reverse voltage so that the charging voltage of the main capacitor becomes a predetermined level. A zener diode that allows a zener current to flow during the above, and a stop transistor that is turned on by the zener current flowing through the zener diode and short-circuits the input terminal of the oscillation transistor to stop the booster circuit. .

[0010]

FIG. 2 shows a lens-fitted film unit embodying the present invention. The film unit with lens 2 incorporates various photographing mechanisms and a strobe device, and includes a unit main body 3 in which a film cartridge is pre-loaded and a label 4 partially covering the unit main body 3.
It is composed of

A shutter button 6 and a counter window 7 are provided on the upper surface of the unit body 3, and a fin 8 and
A photographing lens 9, an operation lever 10 which is a part of a strobe device, and a strobe light diffusing plate 11 are provided. Also,
On the back side of the unit main body 3, a winding dial 13 is exposed, and a confirmation window 12 is provided near the eyepiece of the finder 8, as shown in FIG. Label 4
The adhesive is applied to the back surface and is attached to the central portion of the unit body 3, and the counter window 7, the finder 8, the photographing lens 9 and the like are exposed to the outside through the openings provided in the respective portions.

The operation lever 10 is used to turn on and off a charge switch 15 (see FIG. 1) for charging, and slides between an ON position where the charge switch 15 is turned ON and an OFF position where the charge switch 15 is turned OFF. Is switched. The charging lever 10 also serves as an operation member for selecting whether or not to use the strobe light emission. The strobe light emission is allowed at the ON position, and the strobe light emission is prohibited at the OFF position. Although not shown, the charging lever 1
Reference numeral 0 is provided with a click mechanism or the like for preventing a deviation from an ON position and an OFF position set by vibration or the like.

As described above, the slidability of the operation lever 10 between the ON position and the OFF position improves the operability at the time of charging, so that the charging can be continued without continuing the operation for charging. It is done so.
The position of the operation lever 10 clearly indicates whether or not charging is being performed and whether or not strobe light is required.

FIG. 1 shows a circuit diagram of the strobe device. The strobe device is roughly divided into a booster circuit 20 and a light emitting circuit 21.
And an auto-cut circuit 30. The booster circuit 20 includes a charge switch 15, a battery 26 having an electromotive force of 1.5 V serving as a power supply of the strobe device, and an NPN-type oscillation transistor 2 forming a known blocking oscillation circuit.
7 and an oscillation transformer 28 for converting the low voltage of the battery 26 to a high voltage.

The oscillation transformer 28 includes a primary coil 31, a secondary coil 32, and a tertiary coil 3, each of which is inductively coupled.
And 3. In this oscillation transformer 28,
Each terminal of the primary coil 31 is a first terminal 28a and a second terminal 2
8b, one terminal of the secondary coil 32 is connected to the fifth terminal 28e.
The other terminal is a fourth terminal 28d which is a common terminal with one terminal of the tertiary coil 33, and the other terminal of the tertiary coil 33 is a third terminal 28c.

The primary coil 31 has a first terminal 28a connected to the collector terminal of the oscillation transistor 27, and a second terminal 28b connected to the positive electrode of the battery 26. The tertiary coil 32 has a third terminal 28c connected to the positive electrode of the battery 26 via a resistor, and a fourth terminal 28d, which is a common terminal with the secondary coil 32, connected to the base of the oscillation transistor 27 via the charge switch 15. Connected to terminal.
The emitter terminal of the oscillation transistor 27 is connected to the negative terminal of the battery 26 and is grounded (GND). The fifth terminal 28e of the secondary coil 32 is connected to the cathode of the rectifier diode 34, and the anode of the rectifier diode 34 is connected to the minus side of the light emitting circuit 21 (the minus terminal of the main capacitor 35). I have.

When the charge switch 15 is turned on, the booster circuit 20 configured as described above operates when a base current flows through the oscillation transistor 27 via the resistor, the tertiary coil 33, and the charge switch 15 described above. Starting, the primary current flowing through the primary coil 31 is repeatedly increased and decreased by the oscillation transistor 27. When the primary current increases, a high voltage, for example, 350 V electromotive force corresponding to the winding ratio with the primary coil 31 is generated in the secondary coil 32. The electromotive force of the secondary coil 32 causes a secondary current to flow through the light emitting circuit 21 via the rectifying diode 34, and charges the main capacitor 35 with the secondary current.

In this strobe device, a light emitting diode 29, which is less expensive than a conventional neon tube, is used to indicate the completion of charging of the main capacitor 35. As the light emitting diode 29, for example, a general light emitting diode having a rising voltage Vf of about 1.8V and emitting light stably at a voltage of about 2V is used. Therefore, since the output voltage from the battery 26 can not be the light emitting diode 29, proportionally vary according to the charging voltage V _MC of the main capacitor 35, when the charging voltage V _MC reaches a predetermined voltage A voltage capable of causing the light to emit light is extracted from the oscillation transformer 28, and the lamp is turned on at this voltage.

The light emitting diode 29 has an anode connected to the fourth terminal 28d of the tertiary coil 33 and a cathode connected to the third terminal 28c via a current limiting resistor. This light-emitting diode 29 has a potential V ₄ (=
The base potential V _BE of the oscillation transistor 27) and the third terminal 2
8c of the potential difference between the potential V _3, or driven by the third and fourth terminal voltage (V ₄ -V _3). When the negative electrode of the battery 26 is set as a reference (potential “0” V) and the electromotive force is generated in each of the coils 31 to 33 of the oscillation transformer 28, the potential V ₄ of the fourth terminal 28 d is set to the main capacitor. Although it is constant irrespective of the charging voltage V _{MC of} 35, the potential V ₃ of the third terminal 28c decreases as the charging voltage V _MC of the main capacitor 35 increases.

This drop in the potential V ₃ is caused by the fact that the higher the charging voltage V _MC becomes, the lower the potential of the fifth terminal 28 of the secondary coil 32 becomes.
This is due to the fact that the potential of e decreases and the secondary coil 32 and the tertiary coil 33 are inductively coupled to each other. Note that N ₂ and N ₃ in the equations represent the number of turns of the secondary coil 32 and the tertiary coil 33, respectively. Further, in this strobe device, the negative charging is performed. Therefore, when the charging voltage _VMC increases, the potential of the negative terminal side of the main capacitor 35 decreases. N ₃ / N ₂ (V ₃ −V ₄ ) = (− V _MC ) −V ₄

At the start of charging, ie, the main capacitor 3
5 from when the charging voltage V _MC is low to a predetermined display charging voltage, for example, 265 V, the tertiary coil has 33
The voltage between the third and fourth terminals (V ₄ −V ₃ ) when an electromotive force is generated in the LED 29 becomes a reverse voltage with respect to the light emitting diode 29 or the voltage between the third and fourth terminals (V ₄ −V ₃ ) is normal, but is smaller than the rising voltage Vf, so that the light emitting diode 29 does not emit light. When the charging voltage V _MC of the main capacitor 35 becomes equal to or higher than the display charging voltage, the voltage between the third and fourth terminals (V ₄ −V ₃ ) when the electromotive force is generated in the tertiary coil 33 rises. Voltage V
f, and each time an electromotive force is generated, the light emitting diode 2
9 emits light. When a back electromotive force is generated in the tertiary coil 33, the charging voltage V
_The light emitting diode 29 does not emit light because the voltage between the third and fourth terminals (V ₄ -V ₃ ) is a reverse voltage regardless of _MC .

When the main capacitor 35 is charged to about the specified charging voltage, the blocking oscillation circuit
In order to perform high-speed oscillation operation at KHz, the light emitting diode 2
The light emission of No. 9 looks visually continuous.
Further, after the main capacitor 35 is charged to the specified charging voltage, the light emitting diode 29 is turned on intermittently in conjunction with intermittent auxiliary charging. Lighting of the light emitting diode 29 notifies the completion of charging. Light emitted from the light emitting diode 29 is guided to the confirmation window 12 through a light guide or the like.

The completion of charging by lighting the light emitting diode 29 is an indication of the presence or absence of strobe light emission, that is, strobe light emission is always performed if shooting is performed during continuous lighting or intermittent lighting. If not, strobe light emission is performed. It also has the meaning of an indication that it will not be performed. For example, in a state in which strobe light can be emitted, the main capacitor 3
5 is charged to approximately the specified charging voltage and the operation lever 10 is in the ON position, and the booster circuit 20 operates continuously or intermittently, so that the light emitting diode 29 is turned on. On the other hand, when strobe light emission is not performed, when the charging voltage V _MC of the main capacitor 35 is low, or when the operation lever 10 is in the OFF position and strobe light emission is prohibited, that is, the charge switch 15 is turned off. The light emitting diode 29 is not turned on because the booster circuit 20 is not operating.

The display of the completion of charging by the light emitting diode 29 and the display of the presence / absence of strobe light emission are performed by turning off the charge switch in a strobe device using a charge switch of a continuous pressing type or a strobe device of an automatic charging stop type. Since the light emitting diode 29 is turned off in conjunction with the stop of the booster circuit at the time or when the charging is completed, it cannot be adopted in consideration of making it possible to appropriately confirm. However, it is possible to switch the selection between charging and flash emission with the operation lever 10 as in the case of this strobe device. Conversely, in order to perform these displays, the selection between charging and flash emission is switched with the operation lever 10. You need to do that.

The automatic cut circuit 30 includes a charge switch 1
It is provided for the purpose of reducing the power consumption of the battery 26 when the user forgets to turn off the battery 5. This auto-cut circuit 30 is incorporated in the booster circuit 20 and includes a zener diode 3
6, a PNP-type stopping transistor 37, a noise absorbing capacitor 38, and the like.

The Zener diode 36 has its anode connected to the minus terminal of the main capacitor 35 and its cathode connected to the base terminal of the stopping transistor 37 via a resistor. The stop transistor 37 has a collector terminal connected to the emitter terminal which is one input terminal of the oscillation transistor 27, and an emitter terminal connected to the base terminal which is the other input terminal of the oscillation transistor 27 via the charging switch 15. Have been.

The auto-cut circuit 3 configured as described above
In the case of 0, the charging voltage V _MC of the main capacitor 35 is applied to the zener diode 36 as a reverse voltage, and a zener current (reverse current) flows through the zener diode 36 when the zener diode 36 is charged to the specified charging voltage. When the Zener current flows as a base current, the stop transistor 37 is turned ON (a state in which the emitter-collector conducts). As a result, the oscillation transistor 27 is turned off by short-circuiting the input terminals (base and emitter terminals),
The booster circuit 20 stops. Therefore, the booster circuit 20
Is stopped by the auto cut circuit 30 after the main capacitor 35 reaches the specified charging voltage during its operation, and the charging is stopped.

The zener diode 36 allows a zener current to flow only when the charging voltage V _MC of the main capacitor 35 is equal to or higher than the specified charging voltage, thereby turning off the stopping transistor 37.
When the main capacitor 35 causes a Zener current to flow or the charge voltage V _MC is lowered below a specified charge voltage by natural discharge, the stop transistor 37 is turned off.
The operation of the booster circuit 20 is permitted, and the charge switch 1
When 5 is ON, the booster circuit 20 starts operating again to perform charging.

In the auto-cut circuit 30, the zener diode 36 having a large operating resistance is used to turn on the stop transistor 37 slightly after the time when the main capacitor 35 reaches the specified charging voltage. As a result, the charging voltage at the time of stopping charging is made slightly higher than the specified charging voltage, and the charging voltage V _MC of the main capacitor 35 becomes lower than the specified charging voltage, that is, until the booster circuit 20 stops or resumes operation. With appropriate time, power consumption is effectively reduced.

Thus, when the charging switch 15 is continuously turned ON without forgetting to return the operation lever 10 to the OFF position, after the main capacitor 35 is charged to the specified charging voltage, the boosting circuit 20 is turned on. Are operated intermittently to reduce the power consumption of the battery 26, and reduce the risk that if the operation lever 10 is not returned to the OFF position for a long time, the strobe emission will not be possible in the next photographing.

When a Zener diode 36 having a small operating resistance is used, the operation interval of the booster circuit 20 becomes shorter or almost continuous. A capacitor or the like having a large capacitance is added, and the capacitor is once charged with a zener current.
Is turned on for a certain time, the stop time of the booster circuit 20 can be lengthened. Of course, such a capacitor is added to an auto-cut circuit using a zener diode having a large operating resistance, and the booster circuit 20
It is also possible to lengthen the stop time of the system.

The auto-cut circuit 30 operates even when the charging switch 15 is continuously turned on to emit a strobe light. Therefore, at the time of shooting, the charging switch 1
5 is intentionally turned on, the charge voltage V of the main capacitor 35 is reduced while the power consumption of the battery 26 is reduced.
_The booster circuit 20 is set so that _MC is maintained at a substantially specified charging voltage.
The auto-cut circuit 30 functions as a circuit for intermittently operating and performing auxiliary charging.

By providing such an auto-cut circuit 30, the cost of the strobe device is increased. However, as described above, the charge is completed by the inexpensive light emitting diode 29 instead of the conventionally used expensive neon tube. By performing the display, an increase in cost is reduced.

The light emitting circuit 21 includes, in addition to the main capacitor 35, a trigger capacitor 40, a light emitting selection switch 41 connected in series to the trigger capacitor 40, a trigger coil 42, a synchro switch 43, and a strobe discharge tube (Xe). Tube 44) and the like. When the light emission selection switch 41 is ON, the trigger capacitor 40 is charged with the secondary current from the booster circuit 20 in the same manner as the main capacitor 35.

The synchro switch 43 is turned on when the shutter blades are fully opened during photographing. Light emission selection switch 41
When the synchro switch 43 is turned on when is turned on,
The charged trigger capacitor 40 is discharged, a discharge current at this time flows to the primary side of the trigger coil 42, and a high voltage, for example, a trigger voltage of 4 KV is generated on the secondary side, and this trigger voltage is transmitted via the trigger electrode 44a. Strobe discharge tube 44
Is applied to As a result, the insulation in the strobe discharge tube 44 is broken, and the electric charge of the main capacitor 35 is discharged in the strobe discharge tube 44, so that strobe light emission is performed.

The light emission selection switch 41 is connected to the operation lever 10
The operation lever 10 is turned on and off, and is turned on when the operation lever 10 is in the ON position, and is turned off when the operation lever 10 is in the OFF position.
That is, the light emission selection switch 41 is linked with the charge switch 15. When the light emission selection switch 41 is ON, the trigger capacitor 40 can be discharged as described above, and therefore, strobe light emission is allowed. Further, when the light emission selection switch 41 is OFF, the discharge of the trigger capacitor 41 is prevented even when the synchronization switch 44 is turned ON, so that the strobe light emission is prohibited.

Next, the operation of the above configuration will be described. The photographer turns the winding dial 13 of the film unit with a strobe to wind up the photographic film and prepare for photographing. The shutter charge is performed by this winding operation. Also, when performing flash photography,
Regardless of the charging voltage of the main capacitor 35, the operation lever 10 is slid to set the position to the ON position, and is set to the OFF position when flash photography is not performed.
The position of the operation lever 10 remains set at that position until photographing is completed.

Since the operation lever 10 is of a slide type, it is possible to clearly confirm whether or not charging is being performed at this position. In the same manner, it is possible to clearly confirm whether or not to use the strobe light by selecting the position of the operation lever 10. Further, once the operation lever 10 is turned to the ON position, there is no need to subsequently perform an operation for continuing charging, so that operability is good.

For example, when the operation lever 10 is set to the ON position, the charge switch 15 and the light emission selection switch 41 are turned ON as shown in FIG. When the charge switch 15 is turned on, a base current flows from the battery 20 through the resistor, the tertiary coil 33, and the charge switch 15, and the oscillation transistor 27 starts operating. When the oscillation transistor 27 starts operating, its collector current flows as the primary current of the primary coil 31. When the primary current starts to flow, an electromotive force is generated in the secondary coil 32, and the feedback current from the secondary coil 32 causes the oscillation transistor 27 to oscillate with an increase in the base current, thereby increasing the primary current. Thus, while the primary current is increasing,
A high voltage electromotive force is generated in the secondary coil 32. And
When the collector current of the oscillation transistor 27 saturates and the primary current does not increase, back electromotive force is generated in each of the coils 31 to 33 of the oscillation transformer 28.

When the back electromotive force is generated, the base current of the oscillation transistor 27 sharply decreases, and the primary current also decreases. Then, after the back electromotive force disappears, the base current flows through the oscillation transistor 27 again, so that the primary current increases.

In this way, the boosting circuit 20 is operated, and the operation is continued while the charging switch 15 is ON. And, during this operation, each of the coils 31 to 33
, An electromotive force and a back electromotive force are alternately and repeatedly generated.

When an electromotive force is generated in the secondary coil 32, a secondary current caused by the electromotive force flows through the rectifying diode 34, and the main capacitor 35 is charged. Further, since the light emission selection switch 41 is ON, the trigger capacitor 40 is charged by the secondary current. As charging of the main capacitor 35 progresses, its charging voltage _VMC increases.

During the operation of the booster circuit 20, when the potential of the negative electrode of the battery 26 is set as a reference (potential 0 V), as shown in FIG. 5A, the potential V ₄ of the fourth terminal 28d becomes
During the period when the electromotive force is generated in the tertiary coil 33, the voltage is high and constant by the voltage between the base and the emitter of the oscillation transistor 27, and when the back electromotive force is generated, the potential drops in a pulse shape. The potential V ₃ of the third terminal 28c is constant in time the electromotive force to the oscillation transformer 28 is generated, the potential rises in a pulse form when the counter electromotive force is generated.

As the charging of the main capacitor 35 progresses and the charging voltage V _MC of the main capacitor 35 increases, the oscillation frequency of the blocking oscillation circuit increases,
The generation cycle of the electromotive force and the back electromotive force gradually decreases.
In addition, as the charging voltage V _MC increases, the third
The potential V ₃ of the terminal 28c is entirely decreased while showing the change as described above. On the other hand, the potential V ₄ of the fourth terminal 28 d when the electromotive force and the back electromotive force are generated does not change even if the charging voltage V _MC of the main capacitor 35 increases. Then, further when the charge progresses, the potential V ₃ of the third terminal 28c and the fourth terminal while the electromotive force tertiary coil 33 occurs 2
8d is lower than the potential V ₄ of.

However, the main capacitor charging voltage V _MC
5A does not reach the display charging voltage, FIG.
As shown in FIG. 5, the potential V ₃ of the third terminal 28c is higher than the potential V ₄ of the fourth terminal 28d while the electromotive force is generated in the tertiary coil 33, and the voltage between the third and fourth terminals (V _4- V
₃₎ or is applied as a reverse voltage of the light emitting diode 29, or although the potential V ₃ becomes forward voltage is lower than the potential V _4, the light emitting diode 29 does not emit light because the voltage thereof is low.

The main capacitor 35 is charged for display.
When the battery is charged to the electrical voltage, as shown in FIG.
While the electromotive force is generated in the secondary coil 33, the third and third
Voltage between four terminals (V_Four-V_Three) Is equal to or higher than the rising voltage Vf.
Will be on top. This generates an electromotive force in the tertiary coil 33
Each time, the voltage between the third and fourth terminals (V_Four−
V _Three) Is applied, and the light emitting diode 29 emits light. This
Light-emitting diode
29 emits light but does not light up clearly, but is charged
Voltage V_MCIs about the specified charging voltage,
The period is further shortened, and the potential V of the third terminal 28c is reduced.
_ThreeBecomes even lower, and the voltage between the third and fourth terminals (V_Four−
V_Three) Will be even higher. For this reason, for example, 2.0V or less
The above forward voltage is applied to the light emitting diode 29, and
By shortening the light emission interval, the light emitting diode 29
Will be brightly and stably lit.

When the main capacitor 35 reaches the specified charging voltage, a Zener current flows through the Zener diode 36. However, since the Zener diode 36 having a large operating resistance is used, the stop transistor 37 is turned ON with a slight delay. Then, the base current stops flowing to the oscillation transistor 27, and the booster circuit 20 stops. That is, the charging of the main capacitor 35 is stopped when the charging voltage V _MC becomes slightly higher than the specified charging voltage.

[0048] After charging stop, the main capacitor 35, by flowing inside the discharge and the Zener current, gradually charging voltage V _MC lowering the V _MC. And, at the moment the charging voltage V _MC falls below a prescribed charging voltage, stopping transistor 37 is no longer Zener current flows turns to OFF. As a result, the base current flows again via the resistor, the tertiary coil 33 and the charging switch 15 which is turned on, and the oscillation transistor 27 starts operating.

Therefore, the boosting circuit 20 operates again, and charging of the main capacitor 35 is started. Then, when the main capacitor 35 is charged to the specified charging voltage by this charging, a zener current flows in the same manner as described above, the boosting circuit 20 is stopped by the stop transistor 37, and the charging is stopped. Hereinafter, similarly, the operation and stop of the booster circuit 20 are repeatedly performed, and the auxiliary charging is performed intermittently so as to maintain the main capacitor 35 at the specified charging voltage.

When the auxiliary charging is performed intermittently, the light emitting diode 29 is also intermittently turned on. The photographer can check the light emitting diode 2 through the confirmation window 12.
When charging is confirmed by the sufficiently bright lighting 9 or intermittent lighting of 9, the shutter button 6 is pressed to take a picture. Also, by confirming the lighting of the light emitting diode 29,
At the same time, it can be confirmed that strobe light emission is always performed.

When the shutter button 6 is pressed, the shutter blades operate, and the synchro switch 43 is turned on when the shutter blades are fully opened. Then, the light emission selection switch 41
Is ON, the trigger capacitor 41 is discharged, and the trigger voltage generated on the secondary side of the trigger coil 42 is applied to the strobe discharge tube 44 via the trigger electrode 35. As a result, the main capacitor 35 is discharged, and the strobe discharge tube 44 emits light.

When the main capacitor 35 is discharged by the strobe light emission, the booster circuit 20 is not stopped by the auto cut circuit 30 and the charge switch 15 is turned on. Start and use the same procedure as above to
Charging of the battery is started. Then, although the booster circuit 20 operates, the light emitting diode 29 does not light up until the main capacitor 35 reaches the charging voltage for display. Therefore, it can be confirmed that the strobe light is not emitted until the charging is completed. .

On the other hand, when the operation lever 10 is set to the OFF position, the charging switch 15 and the light emission selection switch 41
Are OFF. The operation of the operation lever 10 may be performed during charging or after charging is completed. Charge switch 1
When the switch 5 is turned off, the base current stops flowing from the battery 26 to the oscillation transistor 27, so that the booster circuit 20 is stopped and charging is stopped.

For example, even when the main capacitor 35 is charged to a specified charging voltage or more and charging is completed, the light emitting diode 29 does not turn on in response to the stoppage of the boosting circuit 20. This allows the photographer
For example, without confirming the position of the operation lever 10, it is possible to easily know that strobe light emission is prohibited by confirming that the light emitting diode 29 is not lit.

When the shutter button 6 is pressed to take a picture, the synchro switch 43 is turned on at the moment when the shutter blades are fully opened, but since the light emission selection switch 41 is turned off, the trigger capacitor 40 is charged. The trigger capacitor 40 does not discharge. As a result, even if the main capacitor 35 is charged up to the specified charge, the main capacitor 35 is discharged and does not emit strobe light, so that photographing without strobe light emission is performed.

If, for example, the user forgets to return the operation lever 10 to the OFF position after performing flash photography, that is, if the charge switch 15 is kept ON, the main capacitor is operated in the same procedure as described above. 3
After 5 has been charged to the specified charging voltage, the operation and stop of the booster circuit 20 are alternately repeated by the auto cut circuit 30. Therefore, the booster circuit 2 is continuously
The power consumption of the booster circuit 20 is suppressed by the time during which the booster circuit 20 is stopped as compared with when 0 is operated. As a result, even if the charge switch 15 is forgotten to be turned off, unnecessary power consumption of the battery 26 is reduced, and the danger that strobe light emission cannot be performed at the next shooting is reduced.

In the above embodiment, the light emitting diode emits light at the voltage between the third and fourth terminals when an electromotive force is generated in the tertiary coil. It is also possible to perform a charge completion display by causing the light to be emitted when the is generated. In this case, as the voltage between the third and fourth terminals when the back electromotive force is generated becomes higher than the rising voltage Vf in the forward direction and the charging voltage of the main capacitor increases, the light emitting diode It is utilized that the light emission interval becomes shorter. Specifically, before charging is completed, one light emission time is short and the light emission cycle is long, so that the lighting of the light emitting diode is not visually recognized, and the light emission cycle becomes short when the charging voltage reaches a predetermined voltage. To make the lighting of the light emitting diode visible. Also, in addition to the third terminal and the fourth terminal, the charge completion display by the light emitting diode can be performed by using a portion between the third terminal and the ground (= a voltage between the collector and the emitter of the oscillation transistor).

In the above-described embodiment, the operation lever is of the slide type. Alternatively, the ON position and the OFF position can be selectively switched to each other. May be used. For example, the charging switch and the light emission selection switch may be selectively turned on and off by a pull-up operation lever. Also,
By linking the mechanical timer and the operation lever, the operation lever is returned to the OFF position after a certain period of time has elapsed since the operation lever was turned on, and the charging switch and the light emission selection switch are turned off. In addition, useless power consumption can be reduced.

Further, in the above embodiment, the charging voltage of the main capacitor is directly applied to the Zener diode. For example, an intermediate terminal is provided in the secondary coil of the oscillation transformer, and the Zener diode is connected to the intermediate terminal. May be connected. Since the voltage of the intermediate terminal provided in the secondary coil changes proportionally according to the charging voltage of the main capacitor, an auto-cut circuit can also be configured in this manner. In this case, there is an advantage that an inexpensive zener diode having a low zener voltage can be used.

In the above description, the strobe device built in the film unit with the lens has been described. However, the present invention is not limited to this, and the strobe device built in the camera,
It can also be used for a strobe device mounted on a camera.

[0061]

As described above, according to the present invention,
An operation member selectively switched to one of an on position for turning on a charging switch and an off position for turning off the charging switch by an external operation, and in response to the charging voltage of the main capacitor reaching a predetermined level. In addition to providing an auto-cut circuit that stops charging by the booster circuit,
The completion of charging is indicated by a light-emitting diode that emits light based on the voltage taken out of the oscillation transformer, which improves operability when charging and reduces unnecessary power consumption of the battery when the charge switch is forgotten to be turned off. In addition to this, even if an auto-cut circuit is added to reduce power consumption, charging completion display is performed with an inexpensive light emitting diode, so that an increase in cost can be reduced. In addition, it is possible to confirm whether or not strobe light is emitted by turning on the light emitting diode.

Further, a strobe light emission selection switch for permitting or inhibiting the discharge of the strobe discharge tube by the main capacitor is provided, and the light emission selection switch is used in conjunction with the stop of charging by turning off the charge switch according to the position of the operation member. Since the discharge of the strobe discharge tube is prohibited, the necessity of strobe light emission can be selected, as well as whether or not strobe light emission is performed can be clarified by the position of the operation member.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a circuit of a strobe device embodying the present invention.

FIG. 2 is a perspective view showing an appearance of a film unit with a lens.

FIG. 3 is an explanatory view showing a charge confirmation window provided near an eyepiece of a finder;

FIG. 4 is a waveform diagram showing an operation state of each unit when the main capacitor is charged.

FIG. 5 is a waveform diagram showing a potential change of each terminal of the tertiary coil.

[Explanation of symbols]

 Reference Signs List 10 Operation lever 15 Charge switch 20 Boost circuit 26 Battery 27 Oscillation transistor 28 Oscillation transformer 29 Light emitting diode 30 Auto cut circuit 35 Main capacitor 41 Light emission selection switch 43 Synchro switch

Claims (3)

[Claims] 1. An oscillating transistor and an oscillating transformer that operate by being supplied with power from a battery as a power supply while a charging switch is on, convert a low voltage of the battery into a high voltage and charge a main capacitor. A strobe device provided with a booster circuit, an operation member selectively switched to one of an on position where the charge switch is turned on and an off position where the charge switch is turned off by an external operation, and a charging voltage of the main capacitor And an auto-cut circuit that stops the booster circuit in response to reaching a predetermined level, and, during operation of the booster circuit, proportionally changes according to the charging voltage of the main capacitor obtained from the oscillation transformer. When the voltage is applied, the main capacitor lights when the main capacitor reaches a predetermined charging voltage, and indicates that charging is completed. Strobe apparatus characterized by and a diode. 2. A strobe light emission selection switch for permitting or prohibiting discharge of the strobe discharge tube by the main capacitor according to a position of the operation member, and discharging the strobe discharge tube in conjunction with turning off of the charge switch. The strobe device according to claim 1, wherein the strobe device is prohibited. 3. The auto-cut circuit, wherein a charging voltage of the main capacitor or a voltage proportionally changing according to the charging voltage is applied as a reverse voltage, and the charging voltage of the main capacitor becomes higher than the predetermined level. And a stop transistor that is turned on by the Zener current flowing through the Zener diode and short-circuits the input terminal of the oscillation transistor to stop the booster circuit. The strobe device according to claim 1 or 2, wherein: