Patent ID: 8704737

Claim:
A method of driving a pixel element in a matrix of pixel elements of an active matrix display, the pixel element comprising (1) a first capacitive element, (2) a first transistor having a semiconductor channel, a first terminal of the semiconductor channel of the first transistor being electrically connected to a first terminal of the first capacitive element, and (3) a light-emitting element, wherein the first transistor is biased at a bias voltage between the gate of the first transistor and a first terminal of the semiconductor channel of the first transistor, the active matrix display comprising an array of column conducting lines and an array of row conducting lines crossing the array of column conducting lines, the method comprising: setting the bias voltage of the first transistor to a value that is substantially close to a threshold voltage of the first transistor by changing a voltage across the first capacitive element with a current passing through the first transistor; setting the bias voltage of the first transistor to a value that is different from the threshold voltage of the first transistor while substantially maintaining the voltage across the first capacitive element; inducing a change of the bias voltage of the first transistor towards the threshold voltage thereof with a current passing through a resistive element in the pixel element to cause the bias voltage of the first transistor at time t linearly depend upon an exponential decaying function exp(−t/τ) essentially during entire time period that the light-emitting element is emitting light, with the predetermined time constant τ being independent of the intensity of light emitted by the light-emitting element and being essentially independent of time t at least during said entire time period; and terminating light emitted from the light-emitting element after said inducing a change of the bias voltage of the first transistor causes the bias voltage of the first transistor becoming substantially close to the threshold voltage of the first transistor.