Claims
- 1. An automatic flash device responsive to photographic information comprising a power source, a main capacitor chargeable to a predetermined value by said power source, a discharge circuit connected to said main capacitor, a control circuit including variable resistance means coupled to said discharge circuit for controlling the amount of electricity discharged by said discharge circuit in response to distance to the object being photographed and producing a signal when the amount of electricity corresponding to said distance is discharged, a synchronizing contact coupled to said discharge circuit to actuate the discharge circuit for starting the discharge of said main capacitor through said discharge circuit, a flash tube connected to said main capacitor, and trigger means connected to said control circuit and flash tube to trigger said flash tube in response to said signal from the control circuit to cause said flash tube to emit light when the amount of charge at the main capacitor reaches a value which corresponds to said distance.
- 2. An automatic device for operating a flash discharge tube and responsive to the shutter release of a camera, comprising a power source, a main capacitor chargeable to a given value by said power source, a discharge circuit connected to said main capacitor, means coupled to the discharge circuit and responsive to the shutter release means to start the discharge of said main capacitor by said discharge circuit, a control circuit which generates an output when the charge at the main capacitor is discharged to a value corresponding to the distance to the object being photographed, and means coupled to the control circuit and actuated by the output of said control circuit for coupling the capacitor across the tube and generating a signal which triggers the tube.
- 3. An automatic flash device responsive to a shutter release that operates in sequential first and second steps in a camera, comprising a power source, a main capacitor chargeable to a predetermined value by said power source, a discharge circuit connected to said main capacitor, a control circuit coupled to the discharge circuit to constrain the amount of electricity discharged from said discharge circuit to correspond to the distance to the object being photographed, means coupled to the discharge circuit and responsive to the first step of the shutter release means of a camera to start the discharging of the main capacitor, a flash tube connected to said main capacitor, a trigger circuit connected to said flash tube and responsive to the second step of shutter release for flashing of said flash tube.
- 4. An automatic flash responsive to the shutter release of a camera and to the distance to the object being photographed, comprising a power source, a main capacitor chargeable to a certain value by said power source, a discharge circuit connected to said main capacitor, a means coupled to the discharge circuit and actuated by the shutter release means of a camera to start the discharging of said main capacitor, a timer circuit including variable resistor means responsive to the distance, means coupling said timer circuit to said discharge circuit to stop the discharging of the main capacitor by the output of said timer circuit, a flash discharge tube connected across said main capacitor, and trigger means coupled to the flash discharge tube to trigger said flash discharge tube to emit light in response to the output of said timer circuit.
- 5. An automatic flash device operable in response to a power source on the basis of photographic information relating to the distance between the camera and the scene being focused, comprising a power source, a main capacitor coupled to the power source chargeable to a given voltage by said power source, a discharge circuit connected to said main capacitor, shutter release means, actuating means coupled to said discharge circuit and actuated by the shutter release means to start the discharge of said main capacitor, a detecting circuit connected to said main capacitor for detecting the amount of energy discharged from said main capacitor and for generating a triggering signal when the amount of discharged energy reaches predetermined value, distance information setting means contained in said detecting means for setting said predetermined value to correspond to the distance, a flash discharge tube connected across said main capacitor, and trigger means connected to said detecting means to trigger said flash discharge tube by said triggering signal, whereby electric energy is discharged from said main capacitor to emit given amount of flash light corresponding to said distance.
- 6. An automatic flash device operable in response to a power source on the basis of photographic information relating to the distance the camera is from the object being focused, comprising a main capacitor, network means connecting said main capacitor to the power source so that the power source can charge said main capacitor to a predetermined level, circuit means including a discharge circuit connected to the main capacitor for discharging a portion of the energy across said capacitor, control means in said discharge circuit and responsive to said distance, said control means including starting means to start discharge of said main capacitor in accordance with release of the shutter, and said control means including a timing circuit having a variable element the value of which is adjusted according to said distance for establishing the amount of energy discharged from said capacitor on the basis of said distance, flash tube means connected across said capacitor so that said capacitor can ignite said flash tube means when said flash tube means is triggered, and trigger means coupled to said flash tube means and said control means for triggering operation of said flash tube means in response to said signal so that the amount of light emitted by said flash tube means depends upon the energy remaining across said main capacitor.
- 7. The device according to claim 1, wherein said discharge circuit includes switching means actuated when said synchronizing contact is turned on so as to start discharge of said main capacitor.
- 8. The device according to claim 1, wherein said control circuit comprises:
- a. a detecting circuit connected to said main capacitor and including said variable resistance for detecting the amount of energy discharged from said main capacitor in order to generate an output signal corresponding to said distance, and
- b. a switching circuit connected to said detecting circuit and said means coupled to the discharge circuit for actuating said trigger means when said detecting circuit generates the predetermined output.
- 9. The device according to claim 8, wherein said switching circuit comprises a neon light which responds to predetermined output of said detecting circuit.
- 10. An automatic flash responsive to the shutter release of a camera and to the distance to the object being photographed, comprising a power source, a main capacitor chargeable to a given value by said power source, a discharge circuit connected to said main capacitor, starting means coupled to the discharge circuit and actuated by the shutter release means to start the discharge of said main capacitor, a timer circuit actuated in response to discharge of said main capacitor and including variable resistor means responsive to the distance, adjusting means for adjusting said variable resistor corresponding to the distance, a flash discharge tube coupled to said main capacitor, trigger means for triggering said flash discharge tube, coupling means coupling said timer circuit to said trigger means to actuate said trigger means when output of said timer circuit reaches a value corresponding to said distance, the amount of energy discharged from said main capacitor and that remains in said main capacitor being controlled corresponding to said distance to emit flash light.
- 11. An automatic flash according to claim 10, wherein said discharge circuit includes a constant voltage breakdown element connected across said timer circuit.
- 12. An automatic flash according to claim 11, wherein said constant voltage breakdown element is a Zener diode.
- 13. An automatic flash device operable in response to a power source on the basis of photographic information relating to the distance between the camera and scene being focused comprising;
- a. a power source,
- b. storage means connected in said power source and chargeable to a certain value of flash energy by said power source,
- c. a first discharge circuit connected to said storage means,
- d. flash means connected through said first discharge circuit to said storage means,
- e. a second discharge circuit connected to said storage means,
- f. actuating means coupled to said second discharge circuit and actuated by the shutter release means of the camera to start the discharging of said storage means,
- g. a control circuit connected to said second discharge circuit for controlling the amount of energy in said storage means corresponding to said distance, said control circuit including a detecting circuit connected to said storage means to detect the amount of energy in said storage means in order to generate output signal at the time when said energy reaches certain value, said control circuit being responsive to said output signal for ending discharge through said second discharge circuit,
- h. distance information setting means in said detecting circuit for setting a detecting level corresponding to said distance, whereby the amount of energy in said storage means is controlled by said control circuit and,
- i. trigger means coupled to said flash tube means for triggering said flash tube means, said flash tube means discharging certain amount of energy in said storage means through said first discharge circuit to emit flash light.
- 14. An automatic flash device according to claim 13, wherein said second discharge circuit comprises switching means which turns on in accordance with the operation of said shutter release means and turns off in response to the output of said detecting circuit.
- 15. An automatic flash device according to claim 13, wherein said second discharge circuit comprises a thyristor having a gate electrode connected to said actuating means, said actuating means impressing a gate signal on said gate electrode at the time when said actuating means is actuated.
- 16. An automatic flash device according to claim 15, wherein said actuating means includes a discharging circuit connected to said storage means and charged in advance and switching means operated in accordance with said shutter release means for impressing discharging voltage on gate electrode of thyristor, the output terminals of said discharging circuit being connected to gate electrode and the negative electrode of thyristor.
- 17. An automatic flash device according to claim 13, wherein said storage means is a capacitor.
- 18. An automatic flash device according to claim 13, wherein said detecting circuit comprises a switching circuit including a transistor and a bleeder resistor connected in parallel to said storage means, the base of said transistor being connected to said bleeder resistor, said transistor generating a trigger signal when the voltage of the base reaches the predetermined value.
- 19. An automatic flash device according to claim 13, wherein said distance information setting means is a variable resistor the resistance of which varies corresponding to rotation angle of a focus ring mounted on the lens barrel of the camera.
- 20. An automatic flash device according to claim 13, wherein said trigger means is connected to said output of said detecting circuit for triggering said flash tube means in response to the output signal of said detecting circuit.
- 21. An apparatus as in claim 20, wherein said circuit means includes starting means for initiating discharge of said capacitor, and wherein said trigger means responds to said discharge means for triggering the operation of said flash tube means a predetermined time after discharge of said capacitor.
- 22. An apparatus as in claim 21, wherein said control means includes a timing capacitor and said variable element and forming a timing circuit, said variable element being a resistor variable in response to said distance.
- 23. An automatic flash device responsive to photographic information, comprising a power source, a main capacitor chargeable to a predetermined value by said power source, a discharge circuit connected to said main capacitor, a control circuit including variable adjusting means coupled to said discharge circuit for controlling the amount of electricity discharged by said discharge circuit in response to distance to the object being photographed and producing a trigger signal when the amount of electricity is discharged, a shutter release means, an actuating means coupled to said shutter release means and discharge circuit for actuating said discharge circuit in response to the shutter release operation to start the discharging of said main capacitor through said discharge circuit, a flash tube means connected across said main capacitor so that said capacitor can ignite said flash tube means when said flash tube means is triggered, and trigger means coupled to flash tube means for triggering operation of said flash tube means so that the amount of light emitted by said flash tube means depends upon the energy remaining across said main capacitor.
- 24. An automatic flash device operable in response to a power source on the basis of photographic information relating to the distance the camera is from the object being focused, comprising a main capacitor, network means connecting said main capacitor to the power source so that the power source can charge said main capacitor to a predetermined level; circuit means including a discharge circuit connected to the main capacitor for discharging a portion of the energy across said capacitor, control means in said discharge circuit and having a variable element the value of which is adjusted according to said distance for establishing the amount of energy discharged from said capacitor on the basis of said distance, flash tube means connected across said capacitor so that said capacitor can ignite said flash tube means when said flash tube means for triggering operation of said flash tube means so that the amount of light emitted by said flash tube means depends upon the energy remaining across said main capacitor.
Priority Claims (1)
| Number |
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Kind |
| 46-52540 |
Jul 1971 |
JA |
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Parent Case Info
This is a continuation of application Ser. No. 271,516 filed July 13, 1972, now abandoned. The present invention relates to an automatic flash device, and particularly to such an automatic flash device in which the electric charge across a main capacitor of the flash device which has been charged beforehand is associated with the shutter release actions of a camera, such as pressing down of a shutter release or closing of a synchronizing contact, etc. The capacitor is discharged in correspondence to the distance from the subject to the camera, thus obtaining proper illumination or amount of emitting light as corresponding to the distance.
Heretofore, there has been such an automatic flash device that the amount of electricity charged across a main capacitor varies depending on the flash photographing informations for obtaining such an amount of emitting light as corresponding to the flash photographic information such as the distance to an object, the film sensitivity, etc. However, in this conventional type of an automatic flash device, the amount of electricity charged across the main capacitor is controlled before a shutter release action. That is, since an ordinary photographer sets the flash photographic information after the charging of the main capacitor of a flash device is completed, it is necessary to discharge the electric charge which has been so accumulated as corresponding to the value of the set photographic information, or to additionally charge the capacitor during the setting process. Particularly, there is a difficulty in setting the photographing distance in such a case. That is, ordinary focusing cannot be completed by one handling, instead focusing can be done after moving the lens to and fro. Therefore, the charging or discharging of the main capacitor must be done during the focusing process.
However, the present inventors have found that this problem can be eliminated if the amount of electricity charged across a main capacitor is controlled during the shutter releasing action. That is the shutter releasing action is done after all flash photographic information is set and it is impossible to change the same after the shutter release.
An object of the present invention is to provide an automatic flash device in which such an amount of emitting light as corresponding to flash photographic information can be obtained.
Another object of the present invention is to provide an automatic flash device in which the electric charge across a main capacitor is discharged in association with the shutter release operation until such an amount of emitting light as corresponding to the flash photographic information can be obtained.
Further another object of the present invention is to provide an automatic flash device having an indication device to indicate that the electric charge across a main capacitor has been discharged to such an extent that an amount of emitting light as corresponding to the flash photographic information has been obtained.
Still another object of the present invention is to provide an automatic flash device which automatically emits light when the electric charge across a main capacitor is discharged to such an extent that an amount of emitting light as corresponding to the flash photographic information has been obtained.
Further object of the present invention is to provide an automatic flash device having a means to impress voltage onto a flash discharge tube when the charged voltage at a main capacitor is too low.
US Referenced Citations (5)
Continuations (1)
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Number |
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271516 |
Jul 1972 |
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Patent Grant
3976913
