Patent ID: 7859189

Claim:
An active matrix display device comprising an array of display pixels, each pixel comprising: a current-driven light emitting display element comprising an area of light emitting material ( 76 ) sandwiched between electrodes; and a drive transistor circuit for driving a current through the display element, the drive transistor circuit comprising a thin film circuit formed on a substrate, the thin film circuit defining a drive transistor and a light-sensitive device for detecting the brightness of the display element, the light-sensitive device having an input surface, wherein the drive transistor is controlled in response to the light-sensitive device output and wherein each pixel further comprises a light blocking structure formed from existing thin film layers of the structure of the active matrix display device, said thin film layers being comprised of amorphous silicon or low-temperature polysilicon, and wherein said light blocking structure is in the proximity of the light-sensitive device ( 84 ) and at the level of the input surface for preventing the passage of light to the light-sensitive device from a lateral direction.