Trigger device for electronic flash

• US 4,479,704 A
• Filed: 10/11/1983
• Issued: 10/30/1984
• Est. Priority Date: 06/18/1981
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Masunaga, Makoto
• Primary Examiner(s): Gellner, Michael L.
• Application Number:
  US06/540,703
• Time in Patent Office: 385 Days
• Field of Search: 354/129, 354/133, 354/137, 354/413
• US Class Current: 396/187
• CPC Class Codes: G03B 15/05 Combinations of cameras with electronic flash apparatus; Electronic flash units
• CPC Class Codes: G03B 2215/05 Combinations of cameras with electronic flash units
• CPC Class Codes: G03B 9/70 with flash-synchronising contacts

Abstract

A trigger device for an electronic flash so designed that a shutter control signal produces a signal for opening and closing an electromagnetically driven shutter and a timer for delaying the shutter control output signal are provided in such a manner that the flash emits the light in response to the shutter closing operation control signal or the delayed signal from the timer which is later than the other when both signals are produced.

Claims

1. A trigger device for flash comprising:

shutter control signal producing means for producing a shutter opening and closing operation control signal for opening and closing an electromagnetically driven shutter;

timer means for producing a delay output signal after the lapse of a certain predetermined time after the timer starts to operate with the shutter opening operation control signal from the shutter control signal producing means; and

flash trigger signal producing means for producing a trigger signal for causing a flash device to emit the flash in response to the shutter closing operation control signal from the shutter control signal producing means or the delay output signal from the timer means whichever is later when both signals are produced.

2. A trigger device according to claim 1, wherein the shutter closing operation control signal and the delay output signal are respectively a signal corresponding to the rising up of pulse.

3. A trigger device according to claim 1, further comprising an OR circuit to which the output of the shutter control signal producing means and that of the timer means are supplied, the output of the OR circuit being delivered to the flash trigger producing means.

4. A trigger device according to claim 1, wherein the electromagnetically driven shutter is normally urged by a spring to the totally closed position.

5. A trigger device for flash comprising:

shutter control means for producing a current supply signal for actuating electromagnetic means for driving the shutter;

timer means which starts to operate with the current supply signal from the shutter control signal producing means and inverses its output signal after the lapse of a certain predetermined time; and

a flash light trigger device for causing a flash device to emit the flashlight in response to the stop of the current supply signal or the inversed output of the timer means, whichever is later, when the current supply signal from the shutter control means is stopped and the output of the timer means is inversed.

6. A camera comprising:

a shutter device whose shutter blades have a moment of inertia, which needs a certain determined time from the time when a shutter opening operation is started until the shutter has been actually opened and which needs a certain determined time from the time when a shutter closing signal is produced during the shutter opening operation until the shutter starts to actually close;

an electronic flash device; and

an electronic flash trigger device which produces a trigger signal for the electronic flash device after the lapse of a certain determined time from the time when said shutter closing signal is produced until the shutter is actually opened during the period from the time when the driving of the shutter device is driven until the shutter blades of the shutter device are actually opened.

7. An electronic flash trigger device for synchronizing an electronic flash with a shutter device whose shutter blades have a moment of inertia, which needs a certain determined time from the time when a shutter opening operation has been started until the shutter has been actually opened and which needs a certain determined time from the time when the shutter closing signal is produced during the shutter opening operation until the shutter starts to actually close, comprising:

means for producing a trigger signal of the electronic flash device which produces a trigger signal for the electronic flash device after the lapse of a certain determined time from the time when said shutter closing signal is produced until the shutter is actually opened during the period from the time when the shutter device is driven until the shutter blades of the shutter device are actually opened.

8. A camera comprising:

a shutter device which needs a certain determined time from the time when a shutter opening operation has been started until the shutter has been actually opened; and

an electronic flash trigger device which delivers a trigger signal to the electronic flash device synchronized with the camera after the lapse of a certain determined time from the time when said shutter closing signal is produced until the shutter is actually opened during the period from the time when the shutter device is driven until the shutter blades of the shutter device are actually opened.