Patent ID: 8009127

Claim:
An organic light emitting display device, comprising: a data driver adapted to: receive an external voltage; control a drive voltage to be on or off, wherein the drive voltage is controlled to be on when the organic light emitting display device is operating in a normal mode and the drive voltage is controlled to be off when the organic light emitting display device is not operating in the normal mode; and generate and output a data signal; a photo sensor adapted to: sense a brightness of an ambient light to determine a sensed brightness of the ambient light; receive the drive voltage controlled by the data driver; and output a brightness signal based on the sensed brightness of the ambient light, the brightness signal being received by the data driver; a scan driver adapted to generate and transfer a scan signal; and a pixel portion adapted to: receive the data signal and the scan signal; and display an image having a luminance indicative of the brightness signal, wherein the photo sensor comprises: an optical sensing section adapted to output an analog sensing signal corresponding to the sensed brightness of the ambient light; an analog-to-digital converter adapted to convert the analog sensing signal from the optical sensing section into a digital sensing signal; a counter adapted to count a predetermined number during one frame period and generate a corresponding counting signal; a conversion processor adapted to output a control signal based on the digital sensing signal and the counting signal; a register generator adapted to divide the sensed brightness of the ambient light into a plurality of stages of brightness, and store a plurality of register set values corresponding to the plurality of stages of brightness; a first selector adapted to select and output one of the plurality of register set values according to the control signal output from the conversion processor; and a gamma compensation circuit adapted to generate a gamma compensation signal according to the control signal output from the conversion processor.