Patent ID: 8284177

Claim:
A display device including a photo-sensor for detecting ambient light and outputting a photocurrent according to the intensity of the ambient light, wherein the display device comprises: a current sampling unit configured to sample the photocurrent outputted from the photo-sensor and to output a plurality of sampling signals to indicate a magnitude of the photocurrent; and a light detection control unit configured to evaluate an average of the sampling signals outputted from the current sampling unit in a predetermined period; wherein the current sampling unit starts a next sampling period corresponding to an end of one of the sampling signals, and wherein the light detection control unit comprises: an edge detection unit configured to detect an edge of the sampling signals; a reset signal generating unit configured to generate a reset signal when the edge detection unit detects the end of one of the sampling signal, thereby allowing the current sampling unit to start the next sampling period; a counter configured to count the number of starts or ends of the sampling signals detected by the edge detection unit; a differential circuit configured to determine time differentials representing pulse widths between the starts and the ends of the sampling signals detected by the edge detection unit; a memory unit configured to store the time differentials determined by the differential circuit; a timing unit configured to determine a time of the predetermined period when the current sampling unit starts to sample the photocurrent; and an averaging unit configured to determine a sum of the time differentials stored by the memory unit in the predetermined period when passing the predetermined period, and to divide the sum into the number counted by the counter, thereby determining the average of the sampling signals.