Charged-based compensation and parameter extraction in AMOLED displays
First Claim
1. A method of extracting a circuit parameter from a pixel circuit and providing in-pixel compensation for variation or aging of the pixel circuit, the pixel circuit including a light emitting device, a drive transistor to provide a programmable drive current to the light emitting device, a programming input, and a storage device to store a programming signal, the method comprising the steps of:
- causing an in-pixel compensation of the pixel circuit byapplying a reference voltage from a first line to a storage device in the pixel circuit andredirecting to a second line current from a first node between the drive transistor and the light emitting deviceto charge the storage device based on the reference voltage to self-compensate for a variation or aging of the drive transistor or the light emitting device or both in the pixel circuit;
extracting, using a circuit external to the pixel circuit, the circuit parameter from the pixel circuit; and
subsequently driving the pixel circuit using programming information that has been compensated based on at least the extracted circuit parameter.
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Accused Products
Abstract
A system reads a desired circuit parameter from a pixel circuit that includes a light emitting device, a drive device to provide a programmable drive current to the light emitting device, a programming input, and a storage device to store a programming signal. One embodiment of the extraction system turns off the drive device and supplies a predetermined voltage from an external source to the light emitting device, discharges the light emitting device until the light emitting device turns off, and then reads the voltage on the light emitting device while that device is turned off. The voltages on the light emitting devices in a plurality of pixel circuits may be read via the same external line, at different times. In-pixel, charge-based compensation schemes are also discussed, which can be used with the external parameter extraction implementations.
567 Citations
19 Claims
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1. A method of extracting a circuit parameter from a pixel circuit and providing in-pixel compensation for variation or aging of the pixel circuit, the pixel circuit including a light emitting device, a drive transistor to provide a programmable drive current to the light emitting device, a programming input, and a storage device to store a programming signal, the method comprising the steps of:
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causing an in-pixel compensation of the pixel circuit by applying a reference voltage from a first line to a storage device in the pixel circuit and redirecting to a second line current from a first node between the drive transistor and the light emitting device to charge the storage device based on the reference voltage to self-compensate for a variation or aging of the drive transistor or the light emitting device or both in the pixel circuit; extracting, using a circuit external to the pixel circuit, the circuit parameter from the pixel circuit; and subsequently driving the pixel circuit using programming information that has been compensated based on at least the extracted circuit parameter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A pixel circuit having a light emitting device, comprising:
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a drive transistor connected to the light emitting device; a storage device coupled to the drive transistor and storing programming information to cause the light emitting device to emit light according to the programming information via the drive transistor; a first transistor connected between the storage device and a first line for applying a reference voltage from the first line to the storage device; and a second transistor connected between a second line and a first node between the drive transistor and the light emitting device for redirecting to the second line current from the first node; wherein said applying the reference voltage from the first line to the storage device and said redirecting to the second line current from the first node are for charging the storage device based on the reference voltage to self-compensate for a variation or aging of the drive transistor or the light emitting device or both in the pixel circuit causing an in-pixel compensation of the pixel circuit. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification