Voltage detecting device

• US 4,611,898 A
• Filed: 02/13/1985
• Issued: 09/16/1986
• Est. Priority Date: 02/13/1984
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Matsuyama, Shinichi
• Primary Examiner(s): ADAMS JR, RUSSELL E
• Application Number:
  US06/701,125
• Time in Patent Office: 580 Days
• Field of Search: 354/468, 354/484, 354/258.1, 354/266, 354/267.1, 354/268, 354/271.1, 354/234.1, 354/235.1
• US Class Current: 396/301
• CPC Class Codes: G03B 7/26 Power supplies; Circuitry or arrangement to switch on the power source; Circuitry to check the power source voltage

Abstract

A voltage detecting device for a camera for detecting whether or not the voltage of a power source has a prescribed value or a value higher than the prescribed value. A device which makes intermittent voltage detections after the leader screen of a shutter starts running and terminates the voltage detecting action as the follower screen of the shutter runs.

Claims

1. A voltage detecting device for a camera, comprising:

(a) shutter control means for controlling the start of the running of a follower screen of a shutter by control of the power supply to an electromagnetic member;

(b) a voltage detecting circuit for detecting the voltage level of a power source voltage, said circuit performing the detection with connection to an electric load different from said electromagnetic member; and

(c) operating means for intermittently detecting the voltage by means of said voltage detecting circuit during a period of time from the start of the running of a leader screen of the shutter until the start of the running of the follower screen.

2. A voltage detecting device according to claim 1, wherein the voltage detecting circuit makes the detection by supplying power to an electric load which is almost equivalent to that of the electromagnetic member.

3. A voltage detecting device according to claim 1, further comprising an electromagnetic member for the leader screen of the shutter for controlling the start of the running of the leader screen.

4. A voltage detecting device according to claim 3, wherein the electromagnetic member for the leader screen of the shutter is used as the electric load.

5. A voltage detecting device according to claim 1, wherein said operating means obtains an intermittent timing operation from a timer circuit.

6. A voltage detecting device according to claim 1, further comprising:

(d) a comparison circuit for comparing whether or not the voltage level detected by the voltage detecting circuit reaches a predetermined voltage level; and

(e) shutter follower screen running means for forcedly running the follower screen of the shutter when the voltage level detected by the voltage detecting circuit is determined by said comparison circuit as not reaching said predetermined voltage level.

7. A voltage detecting device according to claim 6, wherein said shutter follower screen running means forcedly supplies a power supply signal, for starting the running, to the electromagnetic member for the follower screen of the shutter control means.

8. A voltage describing device according to claim 1, further comprising:

(f) second operating means for putting into effect a voltage detection by the voltage detecting circuit just before the leader screen of the shutter starts running.

9. A voltage detecting device according to claim 8, further comprising:

(g) a second comparison circuit for comparing whether or not the voltage level detected by the voltage detecting circuit has reached a predetermined voltage level; and

(h) shutter leader screen running inhibiting means for inhibiting the running of the leader screen of the shutter when the voltage level detected by the voltage detecting circuit is determined by said second comparison circuit as not reaching the predetermined voltage level.

10. A voltage detecting device according to claim 9, wherein the predetermined voltage level for the second comparison circuit is set at a higher level than that of the predetermined voltage level for the first comparison circuit.

11. A voltage detecting device according to claim 9, wherein the predetermined voltage level for the second comparison circuit is set at about the minimum voltage level necessary for the simultaneous running of both the leader screen and the follower screen.

12. A voltage detecting device for a camera, comprising:

(a) shutter control means for controlling the start of the running of a follower screen of a shutter by control of the power supply to an electromagnetic member;

(b) a voltage detecting circuit for detecting the voltage level of a power source voltage, said circuit performing the detection with connection to an electric load different from said electromagnetic member; and

(c) operating means for intermittently detecting the voltage by means of said voltage detecting circuit during a period of time from the start of the running of a leader screen of the shutter until the start of the running of the follower screen;

and wherein the electromagnetic member for the follower screen of the shutter in the shutter control means is of a type which starts said running by supplying power thereto.

13. A voltage detecting device according to claim 12, wherein the voltage detecting circuit makes the detection by supplying power to an electric load which is almost equivalent to that of the electromagnetic member.

14. A voltage detecting device according to claim 12, further comprising an electromagnetic member for the leader screen of the shutter for controlling the start of the running of the leader screen.

15. A voltage detecting device according to claim 14, wherein the electromagnetic member for the leader screen of the shutter is used as the electric load.

16. A voltage detecting device according to claim 12, wherein said operating means obtains an intermittent timing operation from a timer circuit.

17. A voltage detecting device according to claim 12, further comprising:

(a) a comparison circuit for comparing whether or not the voltage level detected by the voltage detecting circuit reaches a predetermined voltage level; and

(b) shutter follower screen running means for forcedly running the follower screen of the shutter when the voltage level detected by the voltage detecting circuit is determined by said comparison circuit as not reaching said predetermined voltage level.

18. A voltage detecting device according to claim 17, wherein said shutter follower screen running means forcedly supplies a power supply signal, for starting the running, to the electromagnetic member for the follower screen of the shutter control means.

19. A voltage detecting device according to claim 14, further comprising second operating means for putting into effect a voltage detection by the voltage detecting circuit just before the leader screen of the shutter starts running.

20. A voltage device according to claim 19, further comprising:

(a) a second comparison circuit for comparing whether or not the voltage level detected by the voltage detecting circuit has reached a predetermined voltage level; and

(b) shutter leader screen running inhibiting means for inhibiting the running of the leader screen of the shutter when the voltage level detected by the voltage detecting circuit is determined by said second comparison circuit as not reaching the predetermined voltage level.

21. A voltage device according to claim 20, wherein the predetermined voltage level for the second comparison circuit is set at a higher level than that of the predetermined voltage level for the first comparison circuit.

22. A voltage device according to claim 20, wherein the predetermined voltage level for the second comparison circuit is set at about the minimum voltage level necessary for the simultaneous running of both the leader screen and the follower screen.