Systems and methods of hybrid calibration of bias current
First Claim
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1. A system for providing biasing currents to pixels of an emissive display system, each pixel having a light-emitting device, the system comprising:
- a plurality of current biasing elements external to said pixels;
a plurality of current bias lines coupling said plurality of current biasing elements to said pixels; and
a controller coupled to said current biasing elements for controlling a programming of said current biasing elements over a plurality of signal lines;
wherein each current biasing element comprises;
at least one current driving transistor coupled to a current bias line for providing a biasing current over the current bias line; and
a storage capacitance for being programmed and for setting a magnitude of the biasing current provided by the at least one current driving transistor;
wherein the controller'"'"'s controlling the programming of each current biasing element comprises;
during a programming cycle charging the storage capacitance to a defined level; and
subsequent to the programming cycle, during a calibration cycle, partially discharging the storage capacitance as a function of characteristics of the at least one driving transistor.
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Abstract
What is disclosed are systems and methods of compensation of images produced by active matrix light emitting diode device (AMOLED) and other emissive displays. Anomalies in bias currents produced by current biasing circuits for driving current biased voltage programmed pixels are corrected through calibration and compensation while re-using existing data or other lines that can be controlled individually to perform said calibration and compensation.
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Citations
16 Claims
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1. A system for providing biasing currents to pixels of an emissive display system, each pixel having a light-emitting device, the system comprising:
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a plurality of current biasing elements external to said pixels; a plurality of current bias lines coupling said plurality of current biasing elements to said pixels; and a controller coupled to said current biasing elements for controlling a programming of said current biasing elements over a plurality of signal lines; wherein each current biasing element comprises; at least one current driving transistor coupled to a current bias line for providing a biasing current over the current bias line; and a storage capacitance for being programmed and for setting a magnitude of the biasing current provided by the at least one current driving transistor; wherein the controller'"'"'s controlling the programming of each current biasing element comprises; during a programming cycle charging the storage capacitance to a defined level; and subsequent to the programming cycle, during a calibration cycle, partially discharging the storage capacitance as a function of characteristics of the at least one driving transistor. - View Dependent Claims (2, 3, 4, 5)
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6. A system for providing biasing currents to pixels of an emissive display system, each pixel having a light-emitting device, the system comprising:
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a plurality of current biasing elements; a plurality of current bias lines coupling said plurality of current biasing elements to said pixels; a controller coupled to said current biasing elements for controlling a programming of said current biasing elements over a plurality of signal lines; and a monitor coupled to the plurality of current biasing elements for monitoring a biasing current produced by each current biasing element and for storing in a memory a measurement representing said biasing current for each current biasing element; wherein each current biasing element comprises; at least one current driving transistor coupled to a current bias line for providing a biasing current over the current bias line; and a storage capacitance for being programmed and for setting a magnitude of the biasing current provided by the at least one current driving transistor; wherein the controller'"'"'s controlling the programming of each current biasing element comprises; retrieving from said memory said measurement representing said biasing current for the current biasing element; determining a deviation of said biasing current represented by said measurement from an expected biasing current; and charging the storage capacitance to a defined compensated level which compensates for said deviation so that said current biasing element produces the expected biasing current. - View Dependent Claims (7, 8)
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9. A method of providing biasing currents to pixels of an emissive display system, each pixel having a light-emitting device, the emissive display system including a plurality of current biasing elements external to said pixels and a plurality of current bias lines coupling said plurality of current biasing elements to said pixels, each current biasing element including at least one current driving transistor coupled to a current bias line for providing a biasing current over the current bias line and a storage capacitance for being programmed and for setting a magnitude of the biasing current provided by the at least one current driving transistor, the method comprising:
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programming each current biasing element over a plurality of signal lines comprising; charging the storage capacitance to a defined level during a programming cycle; and subsequent to the programming cycle, during a calibration cycle, partially discharging the storage capacitance as a function of characteristics of the at least one driving transistor. - View Dependent Claims (10, 11, 12, 13)
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14. A method of providing biasing currents to pixels of an emissive display system, each pixel having a light-emitting device, the emissive display system including a plurality of current biasing elements, a plurality of current bias lines coupling said plurality of current biasing elements to said pixels, each current biasing element including at least one current driving transistor coupled to a current bias line for providing a biasing current over the current bias line and a storage capacitance for being programmed and for setting a magnitude of the biasing current provided by the at least one current driving transistor, the method comprising:
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monitoring a biasing current produced by each current biasing element; storing in a memory a measurement representing said biasing current for each current biasing element; and programming each current biasing element over a plurality of signal lines comprising; retrieving from said memory said measurement representing said biasing current for the current biasing element; determining a deviation of said biasing current represented by said measurement from an expected biasing current; and charging the storage capacitance to a defined compensated level which compensates for said deviation so that said current biasing element produces the expected biasing current. - View Dependent Claims (15, 16)
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Specification