Control device for periodic flash photographing

• US 4,462,667 A
• Filed: 08/27/1982
• Issued: 07/31/1984
• Est. Priority Date: 09/24/1981
• Status: Expired due to Term

• Current Assignee: Minolta Camera Kabushiki Kaisha Osaka Kokusai Building A Corporation
• Original Assignee: Minolta Camera Kabushiki Kaisha
• Inventors: Fujii, Akira, Beppu, Norio
• Primary Examiner(s): Hix, L. T.
• Assistant Examiner(s): Lee, Douglas S.
• Application Number:
  US06/412,374
• Time in Patent Office: 704 Days
• Field of Search: 354/32-35, 354/60 F, 354/145, 354/135, 354/137, 354/139, 354/149, 354/234, 354/267, 354/145.1, 354/149.1, 354/149.11, 354/267.1, 354/234.1
• US Class Current: 396/206
• CPC Class Codes: G03B 7/16 in accordance with both the intensity of the flash source and the distance of the flash source from the object, e.g. in accordance with the "guide number" of the flash bulb and the focusing of the camera

Abstract

A control device for periodic flash photographies is provided with an actuation timing setting circuit in which actuation timings of a camera are manually set and a timer control circuit which generates a first signal at every set actuation timing and a second signal a given period of time before every set actuation timing. The first signal is applied to a camera release electromagnet of the camera for a camera release operation. The second signal is applied to a voltage booster circuit of an electronic flash device or an external power source for an electronic flash device, so that a control transistor of the voltage booster circuit is made conductive by the second signal to supply current to the base of an oscillation transistor of the voltage booster circuit for the oscillation thereof, whereby the voltage booster circuit generates a high voltage applied to a main capacitor of the electronic flash device for the charging thereof. The generation of the second signal may stop after every set actuation timing, e.g. at the time of closure of a synchronous switch of the camera for firing the electronic flash tube.

Claims

1. A control device for use with a camera having an electromagnetic camera release means and an electronic flash device including a battery cell, a flash tube, a main capacitor storing electricity for firing said flash tube and a voltage booster converter circuit with an oscillation transistor and a semiconductive switching element switchable to effect current supply to the base of said oscillation transistor for raising the voltage of said battery cell by the oscillation of said oscillation transistor to generate a high voltage applied to said main capacitor for the charging thereof, said control device comprising:

actuation timing setting means for manually setting timed actuations of said camera;

timer control means for generating a first signal at each said timed actuations and for generating a second signal a given period of time before each said timed actuations;

first signal applying means for applying said first signal to said electromagnetic camera release means for the actuation thereof; and

second signal applying means for applying said second signal to said semiconductive switching element for the switching thereof to effect the current supply to the base of said oscillation transistor.

2. A control device as defined in claim 1, further comprising a switch manually switchable for actuating said timer control means.

3. A control device as defined in claim 1, wherein said first signal applying means includes a second semiconductive switching element switched in response to said first signal to actuate said electromagnetic camera release means, and said second signal applying means includes a third semiconductive switching element switched in response to said second signal for the switching of said semiconductive switching element of said voltage booster converter circuit to effect the current supply to the base of said oscillation transistor.

4. A control device as defined in claim 1, wherein said timer control means is adapted to stop generating said second signal a given period of time after each said timed actuations.

5. A control device as defined in claim 1, further comprising a terminal section through which said second signal is applied to said semiconductive switching element of said voltage booster converter circuit of said electronic flash device.

6. A combination for periodic flash photographing, comprising:

a camera comprising;

an electromagnetic camera release means and

a synchronous switch switched in synchronism with full shutter opening;

an electronic flash device comprising;

a battery cell,

a flash tube,

a trigger circuit for firing said flash tube in response to the switching of said synchronous switch,

a main capacitor storing electricity for firing said flash tube and

a voltage booster converter circuit having an oscillation transistor and a semiconductive switching element switchable to effect current supply to the base of said oscillation transistor, said voltage booster converter circuit raising the voltage of said battery cell by the oscillation of said oscillation transistor to generate a high voltage applied to said main capacitor for the charging thereof; and

a control device comprising;

actuation timing setting means for manually setting timed actuations of said camera for periodic photographing; and

timer control means for generating at each said timed actuations a first signal applied to said electromagnetic camera release means for the actuation thereof and for generating at a given period of time before each said timed actuations a second signal applied to said semiconductive switching element for the switching thereof to effect the current supply to the base of said oscillation transistor, said given period of time being determined such that said electronic flash device is conditioned for firing in advance of the generation of said first signal.

7. A combination as defined in claim 6, wherein said camera, said electronic flash device and said control device are provided separately from one another, and wherein said camera and said control device have electrically connectable terminal sections for transmitting said first signal, said electronic flash device and said control device have electrically connectable terminal sections for transmitting said second signal, and said camera and said electronic flash device have electrically connectable terminal sections which transmit the condition of the switching of said synchronous switch to said trigger circuit.

8. A combination as defined in claim 7, wherein said electronic flash device further includes a normally closed switch the closure of which causes the switching of said semiconductive switching element for providing the power supply to the base of said oscillation transistor, and wherein said control device further includes means for opening said normally closed switch upon the establishment of the electric connection between said electronic flash device and said control device.

9. A combination as defined in claim 7, wherein said control device further includes a switch manually switchable for actuating said timer control means.

10. A combination as defined in claim 7, wherein said camera further includes a switch manually switchable for actuating said electromagnetic camera release means.

11. A combination as defined in claim 6, wherein said timer control means is adapted to stop generating said second signal a given period of time after each said timed actuations.

12. A control device for use with a camera having an electromagnetic camera release means, an electronic flash device including, a flash tube and a main capacitor for storing electricity for firing said flash tube, and an external power source for said electronic flash device including a battery cell and a voltage booster converter circuit having an oscillation transistor and a semiconductive switching element switchable to effect current supply to the base of said oscillation transistor and which raises the voltage of said battery cell by the oscillation of said oscillation transistor to generate a high voltage applied to said main capacitor for the charging thereof, said control device comprising:

actuation timing setting means for manually setting timed actuations of said camera; and

timer control means for generating a first signal at each said timed actuations and for generating a second signal at a given period of time before each said timed actuations;

a first signal applying means for applying said first signal to said electromagnetic camera release means for the actuation thereof; and

a second signal applying means for applying said second signal to said semiconductive switching element for the switching thereof to effect the current supply to the base of said oscillation transistor, said given period of time being determined such that said electronic flash device is conditioned for firing in advance of the generation of said first signal.

13. A control device as defined in claim 12, further comprising a switch manually switchable for actuating said timer control means.

14. A control device as defined in claim 12, wherein said first signal applying means includes a second semiconductive switching element switched in response to said first signal to actuate said electromagnetic camera release means, and said second signal applying means includes a third semiconductive switching element switched in response to said second signal for the switching of said semiconductive switching element of said voltage booster converter circuit to effect the current supply to the base of said oscillation transistor.

15. A control device as defined in claim 12, wherein said timer control means is adapted to stop generating said second signal a given period of time after said timed actuations.

16. A control device as defined in claim 12, further comprising a terminal section through which said second signal is applied to said semiconductive switching element of said voltage booster converter circuit of said external power source.

17. A combination for periodic flash photographing, comprising:

a camera automatically capable of repeated photographing comprising;

an electromagnetic camera release means and

a synchronous switch switched in synchronism with full shutter opening;

an electronic flash device comprising;

a flash tube,

a trigger circuit for firing said flash tube in response to the switching of said synchronous switch, and

a main capacitor storing electricity for firing said flash tube;

an external power source for said electronic flash device, comprising;

a battery cell, and

a voltage booster converter circuit having an oscillation transistor and a semiconductive switching element switchable to effect current supply to the base of said oscillation transistor, said voltage booster converter circuit raising the voltage of said battery cell by the oscillation of said oscillation transistor to generate a high voltage applied to said main capacitor of said electronic flash device for the charging thereof; and

a control device comprising;

actuation timing setting means for manually setting timed actuations of said camera for periodic photographing; and

timer control means for generating at said timed actuations a first signal applied to said electromagnetic camera release means for the actuation thereof and for generating a given period of time before said timed actuations a second signal applied to said semiconductive switching element for the switching thereof to effect the current supply to the base of said oscillation transistor, said given period of time being determined such that said electronic flash device is conditioned for firing in advance of the generation of said first signal.

18. A combination as defined in claim 17, wherein said camera, said electronic flash device, said external power source and said control device are provided separately from one another, and wherein said camera and said control device have electrically connectable terminal sections for transmitting said first signal, said control device and said external power source have electrically connectable terminal sections for transmitting said second signal, said camera and said electronic flash device have electrically connectable terminal sections which transmit the switching of said synchronous switch to said trigger circuit, and said external power source and said electronic flash device have electrically connectable terminal sections which transmit the high voltage generated by said booster circuit to said main capacitor.

19. A combination as defined in claim 18, wherein said external power source further includes a normally closed switch the closure of which causes the switching of said semiconductive element for providing the current supply to the base of said oscillation transistor, said switch being adapted to be opened upon the establishment of the electric connection between said external power source and said control device.

20. A combination as defined in claim 17, wherein said control device further includes a switch manually switchable for actuating said timer control means.

21. A combination as defined in claim 17, wherein said timer control means is adapted to stop generating said second signal a given period of time after said timed actuations.

22. A combination as defined in claim 19, wherein said electronic flash device further includes a battery cell, a power switch, a voltage booster converter circuit which raises the voltage of said battery cell of said electronic flash device to generate a high voltage applied to said main capacitor for the charging thereof, and a switch interlocked with said power switch to be opened upon opening of said power switch and arranged to interrupt the current supply to the base of said oscillation transistor of said voltage booster converter circuit of said external power source by the opening thereof even when said switch of said external power source remains closed.