Patent ID: 8477121

Claim:
A method of operating a pixel array having at least one pixel circuit, the pixel circuit including a switch, a select line connected to the switch, a drive transistor coupled to a data line via the switch and to a power supply line, a light emitting device coupled to the drive transistor, and a storage capacitor coupled to the drive transistor, the method comprising: repeating an operation cycle defining a frame period for a pixel circuit, including at each frame period: programming during the operation cycle the pixel circuit responsive to driving the select line from a first state to a second state to select the pixel for programming, the programming including providing a programming data on the data line; responsive to the programming, driving the pixel circuit during a driving cycle of the operation cycle responsive to driving the select line from the second state to the first state; and responsive to the driving, relaxing a stress effect on the pixel circuit during a relaxing cycle of the operation cycle, prior to a next frame period, the relaxing including driving the select line from the first state to the second state during a first operating cycle of the relaxing cycle followed by driving the select line from the second state to the first state during a second operating cycle of the relaxing cycle so that the pixel circuit is off during said the second operating cycle, the relaxing further including, during the first operating cycle, changing the data line to a voltage smaller than V T0 +V OLED0 , where V TO is a threshold voltage of the drive transistor in an unstressed state and V OLED0 is an ON voltage of the light emitting device in an unstressed state, wherein the pixel circuit is off at the second operating cycle, and wherein the power supply line has a positive voltage during the driving driving cycle and the relaxing cycle.