Camera capable of measuring power source voltage

• US 5,701,527 A
• Filed: 12/21/1994
• Issued: 12/23/1997
• Est. Priority Date: 12/27/1993
• Status: Expired due to Term

• Current Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Original Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Inventors: Sakabe, Namiko, Suzuki, Takashi, Kobayashi, Yoshiaki, Ishimaru, Toshiaki
• Primary Examiner(s): Metjahic, Safet
• Assistant Examiner(s): Nelson, Eric
• Application Number:
  US08/360,406
• Time in Patent Office: 1,098 Days
• Field of Search: 354/484, 354/127.1, 354/127.12, 324/427, 324/433, 324/43, 340/636, 320/48, 320/39, 396/277, 396/279
• US Class Current: 396/277
• 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 battery check device for a camera which includes a discharging circuit to which current flows from a battery and a discharging time setting device for setting a discharging time for determining that an internal resistance of the battery has increased due to non-use of the battery so as to temporarily reduce an output voltage of the battery. The discharging time set by the discharging time setting device is longer than a time required to check the residual energy amount of the battery. A determining device determines whether a voltage of the discharging circuit has reached a reference voltage specific to the battery within the discharging time. It is determined that the residual energy amount of the battery is sufficient and that the internal resistance of the battery has merely increased due to non-use of the battery when the determining device determines that the voltage of the discharging circuit has reached the reference voltage specific to the battery within the discharging time but after the time required to check the residual energy amount of the battery. And it is determined that the residual energy amount of the battery is insufficient when the determining device determines that the voltage of the discharging circuit has not reached the reference voltage specific to the battery within the discharging time.

Claims

1. A battery check device for a camera, comprising:

a discharging circuit to which current flows from a battery;

discharging time setting means for setting a discharging time for determining that an internal resistance of the battery has increased due to non-use of the battery so as to temporarily reduce an output voltage of the battery, said discharging time being longer than a time required to check a residual energy amount of the battery;

determining means for determining whether a voltage of said discharging circuit has reached a reference voltage specific to the battery within said discharging time; and

mode state determining means for determining whether an operating mode of a camera remains in a normal mode in which the camera performs a normal photographic sequence or whether the operating mode of the camera has been changed to the normal mode from a power-saving mode in which the camera consumes less power than in the normal mode;

wherein said discharging time setting means includes;

(i) means for setting a discharging time corresponding to the time required to check the residual energy amount of the battery when said mode state determining means determines that the operating mode of the camera remains in the normal mode; and

(ii) means for setting said discharging time for determining that the internal resistance of the battery has increased due to non-use of the battery when said mode state determining means determines that the mode of the camera has been changed to the normal mode from the power-saving mode; and

wherein the residual energy amount of the battery is determined to be insufficient when said determining means determines that the voltage of said discharging circuit has not reached the reference voltage specific to the battery within said discharging time.

2. The battery check device according to claim 1, wherein said battery check device further comprises operation stopping means for stopping an operation of a camera when said determining means determines that the voltage of said discharging circuit has not reached the reference voltage specific to said battery within said discharging time.

3. A camera having a battery check function, said camera comprising:

a discharging circuit to which current flows from a battery in the camera;

mode switching means for switching an operating mode of the camera between a normal mode in which the camera performs a normal photographic sequence and a power-saving mode in which the camera consumes less power than in the normal mode;

mode state determining means for determining whether the operating mode of the camera remains in the normal mode or has been changed to the normal mode from the power-saving mode;

discharging time setting means for setting a first discharging time of the battery when the mode state determining means determines that the operating mode of the camera remains in the normal mode and for setting a second discharging time longer than the first discharging time when the mode state determining means determines that the operating mode of the camera has been changed to the normal mode from the power-saving mode, said first discharging time corresponding to a time required to check a residual energy amount of the battery and said second discharging time corresponding to a time required to determine whether an internal resistance of the battery has increased so as to temporarily reduce an output voltage of the battery;

voltage detecting means for detecting the voltage of the discharging circuit;

voltage comparing means for comparing the detected voltage of the discharging circuit with a reference voltage specific to the battery;

battery power determining means for;

(i) determining that the residual energy amount of the battery is insufficient when the first discharging time has been set and said voltage comparing means determines that the detected voltage of the discharging circuit is lower than the reference voltage after the first discharging time has elapsed;

(ii) determining that the internal resistance of the battery has increased so as to temporarily reduce an output voltage of the battery when the second discharging time has been set and said voltage comparing means determines that the voltage of the discharging circuit is lower than the reference voltage after the first discharging time has elapsed but higher than the reference voltage after the second discharging time has elapsed; and

(iii) determining that the residual energy amount of the battery is insufficient when the second discharging time has been set and said voltage comparing means determines that the voltage of the discharging circuit is lower than the reference voltage after the second discharging time has elapsed; and

operation stopping means for stopping an operation of the camera when said battery power determining means determines that the residual energy amount of the battery is insufficient.

4. A camera having a battery check function, said camera comprising:

a discharging circuit to which current flows from a battery in the camera;

mode state determining means for determining whether an operating mode of the camera remains in a normal mode or has been changed to the normal mode from a power-saving mode in which the camera consumes less power than in the normal mode;

discharging time setting means for setting a first discharging time of the battery when the mode state determining means determines that the operating mode of the camera remains in the normal mode and for setting a second discharging time longer than the first discharging time when the mode state determining means determines that the operating mode of the camera has been changed to the normal mode from the power-saving mode, said first discharging time corresponding to a time required to check a residual energy amount of the battery and said second discharging time corresponding to a time required to determine whether an internal resistance of the battery has increased so as to temporarily reduce an output voltage of the battery;

voltage comparing means for comparing a reference voltage specific to the battery with a voltage of the discharging circuit detected;

operation stopping means for stopping an operation of the camera when (i) the first discharging time has been set and said voltage comparing means determines that the detected voltage of the discharging circuit is lower than the reference voltage after the first discharging time has elapsed; and

(ii) the second discharging time has been set and said voltage comparing means determines that the voltage of the discharging circuit is lower than the reference voltage after the second discharging time has elapsed; and

means for enabling the camera to perform a normal photographic sequence when the second discharging time has been set and said voltage comparing means determines that the voltage of the discharging circuit is lower than the reference voltage after the first discharging time has elapsed but higher than the reference voltage after the second discharging time has elapsed.

5. The camera according to claim 4, wherein a predetermined operation sequence of the camera is initiated by a plurality of switch means which are operated responsive to one of opening or closing of a rear cover of the camera and inserting a battery in the camera.

6. The camera according to claim 5, wherein the reference voltage is higher than a voltage of the battery required to begin the predetermined operation sequence of the camera.

7. A camera capable of operating in a normal mode in which the camera performs a normal photographic sequence and a power-saving mode in which the camera consumes less power than in the normal mode, comprising:

a discharging circuit connected to a power source of the camera;

mode state determining means for determining whether the operating mode of the camera remains in the normal mode or has been changed to the normal mode from the power-saving mode;

discharging time setting means for setting a discharging time during which a current flows from said power source to the discharging circuit, said discharging time being set in accordance with an output of said operation state detecting means; and

power source checking means for measuring a discharge voltage of said power while said power source is discharged for said discharging time set by said discharging time setting means, and for comparing the measured discharge voltage with a predetermined voltage to thereby detect a residual energy amount of said power source.

8. A camera according to claim 7, wherein said discharge time setting means includes means for setting a first discharging time When said mode state determining means determines that the operating mode of the camera has been changed to the normal mode from the power-saving mode, and for setting a second discharging time when said mode state determining means determines that the operating mode of the camera remains in the normal mode.

9. A camera according to claim 8, wherein the first discharging time is longer than a time during which an output voltage of the power source remains low due to a temporarily increased internal resistance of the power source.

10. A camera capable of operating in a normal mode in which the camera performs a normal photographic sequence and a power-saving mode in which the camera consumes less power than in the normal mode, comprising:

a discharging circuit connected to a power source of the camera;

mode state determining means for determining whether the operating mode of the camera remains in the normal mode or has been changed to the normal mode from the power-saving mode;

discharging time setting means for setting a first discharging time when said mode state determining means determines that the operating mode of the camera has been changed to the normal mode from the power-saving mode, and for setting a second discharging time when said mode state determining means determines that the operating mode of the camera remains in the normal mode; and

voltage determining means for comparing a voltage of said power source with a predetermined voltage after a current flows from said power source to the discharging circuit during one of the first discharging time and the second discharging time set by said discharging time setting means, and for determining that a residual energy amount of said power source is insufficient when the voltage of said power source is lower than the predetermined voltage.

11. The camera according to claim 10, wherein said voltage determining means is operable responsive to a plurality of switch means which are operated responsive to one of a rear cover of the camera being opened or closed and a power source battery being inserted into the camera.

12. The camera according to claim 10, wherein the first discharging time is longer than a time during which an output voltage of the power source remains low due to a temporarily increased internal resistance of the power source.

13. The camera according to claim 11, wherein said predetermined voltage is higher than a voltage required by said power source to enable operation of the camera.

14. A camera capable of operating in a normal mode in which the camera performs a normal photographic sequence and a power-saving mode in which the camera consumes less power than in the normal mode, comprising:

a discharging circuit connected to a power source of the camera;

mode state determining means for determining whether the operating mode of the camera remains in the normal mode or has been changed to the normal mode from the power-saving mode;

timer means for measuring a first predetermined time;

voltage determining means for causing said discharging circuit to discharge said power source during the first discharging time, and for comparing a voltage of said power source with a predetermined voltage; and

discharging control means for determining that the voltage of the power source is normal when said voltage determining means determines that the voltage of said power source is higher than the predetermined voltage, and for controlling said timer means and said voltage determining means to repeat voltage determination a prescribed number of times while the operating mode of the camera remains in the normal mode when said voltage determining means determines that the voltage of said power source is lower than the predetermined voltage.