Patent ID: 7825361

Claim:
A light sensor test unit built in a display panel to test a light sensor that senses an external light, the light sensor test unit comprising: a test circuit connected to an output node of the light sensor, which outputs a driving signal in response to a sensing signal output from the output node, when the external light having a predetermined intensity is applied to the light sensor; a test pixel part comprising pixels selected from a plurality of pixels arranged in a display area of the display panel, which receives the driving signal from the test circuit to display a gray-scale corresponding to the driving signal on a screen of the display panel; a brightness measurer which measures a brightness corresponding to the gray-scale displayed on the test pixel part; and a controller which compares the measured brightness with a predetermined brightness to test whether the light sensor is normally operated, wherein the test circuit is arranged in a peripheral area of the display panel, and the brightness measurer is positioned above the screen of the display panel to measure the brightness of the test pixel part.