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US 2004/0170215 A1Published application
Method for determining temperature of an active pixel imager and automatic correcting temperature induced variations in an imager
AssigneeAptina Imaging Corporation
InventorsGiuseppe Rossi, Gennadiy A. Agranov
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Abstract
An imager temperature sensor and a current correction apparatus are provided which use dark pixel measurements from an imager chip during operation together with a fabrication process constant as well as a chip dependent constant to calculate chip temperature. The chip temperature may be used to generate a current correction signal. The correction signal is used to tune a current on the imager chip to correct for temperature variations.
Claims112
An imager device comprising:
- a pixel array formed on an imaging chip and comprising at least one pixel providing a dark current signal;
- and
- a circuit for providing a representation of temperature using said dark current signal, a fabrication process dependent parameter, and an imaging chip dependent value.
An imager device comprising:
- a pixel array formed on an imaging chip and comprising at least one pixel providing a dark current signal;
- and
- a circuit for providing a representation of at least one of a temperature of said chip and a temperature of a portion of said chip using said dark current signal, a fabrication process dependent parameter and an imaging chip dependent value.
An imager device comprising:
- a pixel array comprising a plurality of dark pixels, said dark pixels comprising at least one dark pixel for providing a plurality of dark current signals;
- a memory which stores values comprising a process dependent value and at least one other value related to a reference dark current signal measured at a reference temperature;
- and
- a circuit for calculating at least one temperature value based on a sensed dark current value, said process dependent dark current value, and said at least one other value, wherein said sensed dark current value is based on at least one of said plurality of dark pixel signals.
1 more element
An imager device comprising:
- means for providing at least one reference pixel signal;
- and
- means for determining at least one temperature value for said device based on said reference pixel signal, a fabrication process value, and at least one other value related to a reference pixel signal taken from said device at a reference temperature.
An imager device comprising:
- means for providing a dark current signal;
- means for providing a representation of temperature using said dark current signal, a fabrication process dependent parameter, and an imaging chip dependent value;
- and
- means for adjusting at least one temperature dependant parameter of said device using said temperature representation.
1 more element
A method of determining temperature of an imager chip, said method comprising:
- storing a fabrication process dependent value for an imager chip;
- storing at least one chip dependent value representing a measured pixel dark current reference value and a reference temperature at which said chip dependent dark current reference value was measured;
- measuring a dark current value of a pixel on said chip;
- and
- determining a chip temperature representation based on said measured dark current value and stored values.
2 more elements
A method of determining and using temperature values of an imager chip, said method comprising:
- storing a fabrication process dependent value for an imager chip;
- storing at least one chip dependent value representing a measured pixel dark current reference value and a reference temperature at which said chip dependent dark current reference value was measured;
- measuring a dark current value of a pixel on said chip;
- determining a chip temperature representation based on said measured dark current value and stored values;
- and
- correcting at least one temperature dependent parameter of said imager based on a respective said temperature representation.
3 more elements
A method of determining temperature of an imager device, said method comprising:
- acquiring at least one dark current signal from at least one pixel in a pixel array;
- and
- determining a temperature value using said acquired dark current signal together with a fabrication process value, and at least one other value representing a reference dark current signal of a pixel of said pixel array taken at a reference temperature.
A method of determining temperature of an imager chip, said method comprising:
- acquiring at least one dark current signal at a plurality of locations of a pixel array;
- and
- determining an associated temperature value for each of said locations using a respective said at least one dark current signal.
A method of determining an imager chip temperature comprising:
- sampling a dark pixel signal with a first integration time;
- sampling a second dark pixel signal with a second integration time;
- providing a calibrated dark pixel signal using said first and second sampled dark pixel signals;
- and
- calculating a chip temperature using the calibrated dark pixel signal and a fabrication process dependent value related to dark current and temperature, and a chip dependent value related to dark current and temperature.
2 more elements
A method of correcting a temperature dependant parameter for an imager chip comprising:
- determining at least one correction value for an associated at least one temperature dependent parameter of an imager based on a temperature value, said temperature value being determined based upon a pixel value measured during said chip operation, a stored fabrication process dependent value related to dark current and temperature and a chip dependent value related to dark current and temperature;
- and
- using at least one said value to adjust a respective temperature dependant parameter of at least one portion of said imager.
A method of determining an imager chip temperature comprising:
- sampling a first and second dark pixel signals from each of a plurality of dark pixel clusters, each said cluster sampling comprising:
- sampling a first dark pixel signal with a first integration time;
- and
- sampling a second dark pixel signal with a second integration time;
- calculating a calibrated dark pixel signal for each dark pixel cluster using said first and second dark pixel signal of each cluster;
- and
- calculating a separate chip temperature for each said dark pixel cluster using a said calibrated dark pixel signal for each said cluster and a fabrication process dependent value related to dark current and temperature, and a chip dependent value.
4 more elements
A method of correcting a current source on an imager comprising:
- determining a plurality of unique current correction signals, wherein each unique current correction signal is associated with one or more circuit components of an imager chip, wherein said determining of a plurality of unique current correction signals is based on a temperature value associated with said components;
- multiplying each of said unique current correction signal with a current signal to produce a corrected current signal for each component;
- and
- supplying each of said corrected current signals to each associated circuit component.
1 more element
A method of correcting temperature dependant signals on an imager comprising:
- determining a plurality of correction signals, wherein a unique correction signal is associated with one or more circuit components of an imager chip, wherein said determining of a plurality of correction signals are based on a temperature value associated with said components determined based upon a dark pixel signal, a fabrication process dependent value related to dark current and temperature, and a chip dependent value;
- and
- correcting at least one temperature dependent property on said imager based on an associated said correction signal.
Dependencies are inferred from the claim text.