Method and apparatus for adjusting sweep-out frequency of an imaging apparatus responsive to the condition of a power source
An operating condition judging circuit judges a supply voltage level of a power supply source. A controller controls a frequency of sweep-out of unnecessary charge in the imaging element based on an output level of the power supply source for reducing peak consumed current and power consumption and thereby extending battery life.
1. An imaging apparatus having an imaging element for accumulating signal charge corresponding to incident scene light flux in a photo-electric converting element section comprising:
a sweep-out means for sweeping out unnecessary charge in the imaging element;
an operating condition judging means for judging a supply voltage level; and
a control means for lowering a sweep-out frequency of the sweep-out means when a supply voltage level is lower than a predetermined voltage.
2. A method for operating an imaging apparatus having an imaging element for
accumulating signal charge corresponding to incident scene light flux in a photo electric converting element powered by a power source, comprising the steps of:
applying a sweep-out signal having a given frequency for sweeping out unnecessary charge in the imaging element;
monitoring the power source; and
changing the frequency of the sweep-out signal to a lower frequency when a supply voltage level is lower than a predetermined voltage and lies within a given voltage range.
3. A method for operating an imaging apparatus having an imaging element for accumulating signal charge corresponding to incident scene light flux in a photo electric converting element powered by a power source, comprising the steps of:
applying a sweep-out signal having a given frequency for sweeping out unnecessary charge in the imaging element;
monitoring the power source; and
changing the frequency of the sweep-out signal to a lower frequency when a supply voltage level of the power source is lower than a first predetermined voltage and is greater than a second predetermined voltage which is less than said first predetermined voltage.
4. The method of claim 3 further comprising preventing a sweep-out operation when the supply voltage level is less than said second predetermined voltage.
5. A method for operating an imaging apparatus having an imaging element for
accumulating signal charge corresponding to incident scene light flux in a photoelectric converting element powered by a power source and having a shutter release button, comprising the steps of:
monitoring the power source responsive to operation of the shutter release button;
changing a frequency of a sweep-out signal to a lower frequency in preparation for a sweep-out operation to sweep-out unnecessary charge when a supply voltage level is lower than a predetermined voltage and lies within a given voltage range.
6. The method of claim 5 further comprising a lens stop; and
changing frequency of the sweep-out signal to the lower frequency when the lens stop is on.
7. The method of claim 6 further comprising:
lowering the frequency of the sweep-out signal when the lens stop is off and the supply voltage level is less than said first predetermined voltage.
8. A method for operating an imaging apparatus having an imaging element for accumulating signal charge corresponding to incident scene light flux and a photo electric converting element powered by a power source and having a shutter release button movable from an initial position to a partially depressed position and a fully depressed position, comprising:
a) monitoring the power source responsive to operation of the shutter release button to said partially depressed position;
b) changing a frequency of a sweep-out signal to a lower frequency in preparation for a sweep-out operation to sweep out unnecessary charge in the imaging element when a supply voltage level of the power source is lower than a predetermined voltage and lies within a given voltage range;
c) monitoring a lens stop responsive to operation of the shutter release button to the fully depressed position; and
d) changing the frequency of the sweep-out signal to the lower frequency when the lens stop is on.
9. The method of claim 8 wherein step (b) further comprises changing the frequency of the sweep out signal to a higher frequency when the supply voltage level is greater than said first predetermined voltage.
10. The method of claim 8 wherein step (b) further comprises halting operation of the imaging apparatus when the supply voltage level of the power source is less than a second predetermined voltage which is lower than the first mentioned predetermined voltage.
11. The method of claim 8 further comprising returning to step (b) if the release button has not moved to the fully depressed position after completion of step (d).
12. An imaging apparatus comprising:
an imaging element for accumulating signal charge corresponding to incident scene light flux in a photo electric converting element;
a power source for powering said imaging apparatus;
a signal generator having a lower and a higher operating frequency for generating a sweep out signal coupled to said imaging element for sweeping out unnecessary charge from the photo electric converting element;
control means monitoring said power source for controlling said signal generator to generate a sweep out signal having said higher frequency when the supply voltage level is greater than a first predetermined voltage.
13. An imaging apparatus comprising:
an imaging element for accumulating signal charge corresponding to incident scene light flux in a photo electric converting element;
a power source for powering said imaging apparatus;
a signal generator having a lower and a higher operating frequency for generating a sweep out signal coupled to said imaging element for sweeping out unnecessary charge from the photo electric converting element;
control means monitoring said power source for controlling said signal generator to generate a sweep out signal having said higher frequency when the supply voltage level is greater than a first predetermined voltage.
wherein said control means operates said signal generator to generate a sweep out signal of said lower frequency when said supply voltage level is less than said first predetermined voltage and greater than a second predetermined voltage which is lower than said first predetermined voltage.
14. An imaging apparatus comprising:
an imaging element for accumulating signal charge corresponding to incident scene light flux in a photo electric converting element;
a power source for powering said imaging apparatus;
a signal generator having a lower and a higher operating frequency for generating a sweep out signal coupled to said imaging element for sweeping out unnecessary charge from the photo electric converting element;
control means monitoring said power source for controlling said signal generator to generate a sweep out signal having said higher frequency when the supply voltage level is greater than a first predetermined voltage,
wherein said control means includes means to prevent operation of the imaging element when the supply voltage level is less than said second predetermined voltage.
15. An imaging apparatus comprising:
an imaging element for accumulating signal charge corresponding to incident scene light flux in a photo electric converting element;
a power source for powering said imaging apparatus;
a signal generator having a lower and a higher operating frequency for generating a sweep out signal coupled to said imagine element for sweeping out unnecessary charge from the photo electric converting element;
control means monitoring said power source for controlling said signal generator to generate a sweep out signal having said higher frequency when the supply voltage level is greater than a first predetermined voltage.
wherein said imaging apparatus includes a shutter release button, a first switch means operative when a shutter release button is moved to a partially depressed position;
second switch means operative when the shutter release button is moved to a fully depressed position; and
said control means monitoring said power source when said first switch means is operated.
16. The imaging apparatus of claim 15 wherein said control means monitors a condition of a lens stop responsive to operation of said second switch means for reducing the frequency of the sweep-out signal when the lens stop is on.
17. The imaging apparatus of claim 15 wherein said control means monitors a condition of a lens stop responsive to operation of said second switch means for reducing the frequency of the sweep-out signal when a lens stop is not operated and when the supply voltage level is less than said first predetermined value.
18. An imaging apparatus comprising:
an imaging element for accumulating signal charge corresponding to incident scene light flux in a photo electric converting element;
a power source for powering said imaging apparatus;
a signal generator having a lower and a higher operating frequency for generating a sweep out signal coupled to said imaging element for sweeping out unnecessary charge from the photo electric converting element; control means monitoring said power source for controlling said signal generator to generate a sweep out signal having said higher frequency when the supply voltage level is greater than a first predetermined voltage,
wherein said control means reinitiates monitoring of said power source when said second switch means is not operated after completion of a previous battery check sequence.
19. An imaging apparatus comprising:
an imaging element for accumulating signal charge corresponding to incident scene light flux in a photo electric converting element;
a power source for powering said imaging apparatus;
a signal generator having a lower and a higher operating frequency for generating a sweep out signal coupled to said imaging element for sweeping out unnecessary charge from the photo electric converting element;
control means monitoring said power source for controlling said signal generator to generate a sweep out signal having said higher frequency when the supply voltage level is greater than a first predetermined voltage,
wherein said control means prevents monitoring of said power source when said supply voltage level is less than said second predetermined voltage.
20. A method for operating an imaging element for accumulating signal charge corresponding to incident scene light flux in a photo electric converting element, a power source for powering said imaging apparatus, a shutter release button, and a signal generator having a lower and a higher operating frequency for generating a sweep out signal coupled to said imaging element for sweeping out unnecessary charge from the photo electric converting element, said method comprising:
(a) monitoring said power source when the shutter release button is operated to a first position for controlling said signal generator to generate a sweep out signal having said higher frequency when the supply voltage level is greater than a first predetermined voltage; and
(b) monitoring a condition of a lens stop responsive to operation of said shutter release button to a second position of reducing the frequency of the sweep-out signal when a lens stop is not operated and when the supply voltage level is less than said first predetermined value.