Light responsive camera actuation control

• US 4,209,244 A
• Filed: 04/04/1978
• Issued: 06/24/1980
• Est. Priority Date: 04/18/1977
• Status: Expired due to Term

• Current Assignee: Minolta Camera Kabushiki Kaisha
• Original Assignee: Minolta Camera Kabushiki Kaisha
• Inventors: Sahara, Masayoshi, Nakai, Masaaki
• Primary Examiner(s): Hix, L. T.
• Assistant Examiner(s): Perkey, William B.
• Application Number:
  US05/893,397
• Time in Patent Office: 812 Days
• Field of Search: 354/23 D, 354/60 R, 354/60 E, 354/60 L, 354/234, 354/235, 354/238, 354/266-268, 354/51, 354/48, 354/50
• US Class Current: 396/252
• CPC Class Codes: G03B 7/083 for control of exposure time

Abstract

In camera control circuitry including an exposure control circuit for controlling exposure factor or exposure factors, e.g. exposure time and/or diaphragm aperture, in accordance with an output of a light measuring circuit and further including an electromagnetic means for initiating the camera operation, a delay circuit delays the actuation of the exposure control circuit and the electromagnetic means for a short time period. A power supply circuit for the exposure control circuit, the light measuring circuit, the electromagnetic means and the delay circuit, is closed by the closure of a manually controlled switch and the closing condition of the power supply circuit is maintained through a self-maintaining circuit. When the scene brightness is outside of an available range for the exposure control circuit, a detecting circuit generates an output to make inoperative the delay circuit and the self-maintaining circuit so that the exposure control circuit and the electromagnetic means are not actuated. The delay circuit may also be used for self-timer photography.

Claims

1. Camera control circuitry, comprising:

a light measuring circuit for generating an output representative of a scene to be photographed;

electromagnetic means for initiating camera operation;

an energization circuit for energizing said electromagnetic means;

a power supply circuit for supplying electric energy to said light measuring circuit;

a switch member for actuating said power supply circuit;

a circuit for self-maintaining the actuated condition of said power supply circuit;

a delay circuit for generating a first output signal when a given time period has lapsed after the actuation of said power supply circuit, said energization means being connected to said delay circuit to be energized by said first output signal and said power supply circuit being connected to said delay circuit to energize the latter;

a detecting circuit for generating a second output signal when said output from said light measuring circuit exceeds a given limit; and

means for preventing the operation of said delay circuit and said self-maintaining circuit in response to said second output signal.

2. The camera control circuitry as in claim 1 further comprising means for releasing the self-maintenance of said power supply circuit in response to the termination of the exposure.

3. The camera control circuitry as in claim 1 wherein said delay circuit includes a capacitor and a switching circuit for generating said first output signal when said capacitor is charged to a given level, and said prevention means includes a semiconductor switching element connected across said capacitor and is responsive to said second output to short-circuit said capacitor.

4. The camera control circuitry as in claim 3 wherein said self-maintaining circuit includes a first transistor shunted across said switch member, a second transistor having an output connected to the base of said first transistor to actuate the latter, and a biasing element for actuating said second transistor, said biasing element being actuated with either said switch member or said first transistor being conductive.

5. The camera control circuitry as in claim 4 wherein said prevention means includes a third transistor responsive to said second output signal to turn off said first transistor.

6. The camera control circuitry as in claim 4 wherein said self-maintaining circuit further includes means for actuating said first transistor in response to said first output.

7. The camera control circuitry as in claim 4 or 6 further comprising means for releasing the self-maintenance of said power supply circuit in response to the termination of the exposure.

8. The camera control circuitry as in claim 1 wherein said delay circuit includes a capacitor, a first resistor means for providing a given short time of delay, a second resistor means for providing a delay time necessary for self-timer photography, and selector means for selectively coupling said first and second resistor means with said capacitor.

9. The camera control circuitry as in claim 8 further comprising an indicator member, drive means for intermittently actuating said indicator member, and means for deactuating said drive means in response to said first output signal.

10. The camera control circuitry as in claim 8 further comprising means for deactuating said drive means in response to said second output signal.

11. Camera control circuitry, comprising:

a light measuring circuit for generating an output representative of a scene to be photographed;

an exposure control circuit for controlling at least one exposure factor;

an electromagnetic means for initiating camera operation;

an energization circuit for energizing said electromagnetic means;

a first power supply circuit for supplying electric energy to said light measuring circuit;

a first manually operable switch member for actuating said first power supply circuit;

a second power supply circuit;

a second switch member for actuating said second power supply circuit;

a circuit for self-maintaining the actuated condition of said second power supply circuit;

a delay circuit connected to said second power supply circuit to be energized thereby for generating a first output signal when a given time period has lapsed after the actuation of said second power supply circuit, said energization means and said exposure control circuit being connected to said delay circuit to be actuated by said first output signal;

a detecting circuit coupled to said light measuring circuit for generating a second output signal when said output from said light measuring circuit exceeds a given limit; and

means for preventing the operation of said delay circuit and said self-maintaining circuit in response to said second output signal.

12. The camera control circuitry as in claim 11 further comprising a third switch means arranged substantially in parallel with said first switch member for actuating said first power supply circuit, said third switch means being responsive to the actuation of said second power supply circuit.

13. The camera control circuitry as in claim 12 wherein said second switch member includes a first switch means responsive to a shutter release operation, and a second switch means responsive to a remote control operation, said first and second switch means being connected parallelly with each other to said second power supply circuit.

14. Camera control circuitry comprising:

a power source;

a light measuring circuit, having an output terminal, for generating an exposure control signal corresponding to the scene brightness;

first switch means actuated at a first stage of shutter button depression;

a first power supply circuit connected to said power source to form a power supply path to said light measuring circuit in response to the actuation of said first switch means;

a second switch means which is actuated at a second stage of shutter button depression;

a second power supply circuit connected to said power source and having an output terminal for providing electric energy therethrough, the second power supply circuit being actuated to a power supply state in response to the actuation of said second switch means;

a delay circuit receiving electric power from said output terminal of said second power supply circuit, and for generating a first output signal when a given time period has lapsed after the actuation of said second power supply circuit;

electromagnetic means for initiating a shutter operation;

an energization circuit for energizing said electromagnetic means in response to said first output signal, said energization circuit being connected with said output terminal of said second power supply circuit to receive electric power therefrom;

a circuit for self-maintaining the actuated state of said second power supply circuit;

a detecting circuit having an input terminal connected to said output terminal of said light measuring circuit, and an output terminal for generating a second output signal when said exposure control signal exceeds a given level;

means for preventing the operation of said delay circuit and self-maintaining circuit with occurrence of said second output signal, said preventing means functionally connected to said output terminal of said detecting circuit;

a third switch connected in parallel with said second switch means to said second power supply circuit for actuating the latter independently of said second switch means; and

a fourth switch means for actuating said first power supply circuit in response to the actuation of said second power supply circuit.