Pixel circuits for AMOLED displays
First Claim
1. A display system comprising:
- a reference voltage source;
a supply voltage source; and
a plurality of pixels arranged in an array, each pixel comprising a pixel circuit including;
a light-emitting device,a drive transistor for driving current through the light emitting device according to a driving voltage across the drive transistor during an emission cycle, said drive transistor having a gate, a source, a drain and a threshold voltage,a storage capacitor coupled to said drive transistor for storing said driving voltage, anda reference voltage transistor coupled to the reference voltage source for coupling the drive transistor to the reference voltage source during a first operation cycle for charging a node common to said storage capacitor and said light-emitting device to the reference voltage, said reference voltage having a magnitude that turns off said light-emitting device, the reference voltage transistor for isolating the drive transistor from the reference voltage source during a second operation cycle subsequent to the first operation cycle for allowing said drive transistor to transfer to said node, a voltage that is a function of the threshold voltage and mobility of said drive transistor.
2 Assignments
0 Petitions
Accused Products
Abstract
A system is provided for controlling an array of pixels in a display in which each pixel includes a light-emitting device and a reference voltage source that controllably supplies a reference voltage having a magnitude that turns off the light-emitting device. While the reference voltage is coupled to a drive transistor, a control voltage is supplied to the gate of the drive transistor to cause the drive transistor to transfer to a node common to the drive transistor and the light-emitting device, a voltage that is a function of the threshold voltage and mobility of the drive transistor. During an emission cycle, the current conveyed through the light emitting device via the drive transistor is controlled by a voltage stored in the storage capacitor, which is a function of the threshold voltage and mobility of the drive transistor so that the current supplied to the light-emitting device remains stable.
506 Citations
14 Claims
-
1. A display system comprising:
-
a reference voltage source; a supply voltage source; and a plurality of pixels arranged in an array, each pixel comprising a pixel circuit including; a light-emitting device, a drive transistor for driving current through the light emitting device according to a driving voltage across the drive transistor during an emission cycle, said drive transistor having a gate, a source, a drain and a threshold voltage, a storage capacitor coupled to said drive transistor for storing said driving voltage, and a reference voltage transistor coupled to the reference voltage source for coupling the drive transistor to the reference voltage source during a first operation cycle for charging a node common to said storage capacitor and said light-emitting device to the reference voltage, said reference voltage having a magnitude that turns off said light-emitting device, the reference voltage transistor for isolating the drive transistor from the reference voltage source during a second operation cycle subsequent to the first operation cycle for allowing said drive transistor to transfer to said node, a voltage that is a function of the threshold voltage and mobility of said drive transistor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
Specification