Light sensor test unit, method of testing light sensor using the same and display apparatus

A method of testing a light sensor built in a display panel, to sense an external light, comprising:

• providing a predetermined external light to the light sensor:
• outputting a sensing signal corresponding to the external light through an output node of the light sensor:
• outputting a driving signal to pixels selected from a plurality of pixels arranged in the display panel in response to the sensing signal:
• displaying a gray-scale corresponding to the driving signal through the selected pixels:
• measuring a brightness corresponding to the gray-scale in a region where the selected pixels are arranged;
• and
• comparing the measured brightness with a predetermined reference brightness to test whether the light sensor is normally operated.

A display apparatus comprising:

• a backlight unit which generates an internal light;
• a display panel including a plurality of pixels which is arranged in a display area and receives the internal light to display an image, and a light sensor which is arranged in a black matrix area adjacent to the display area and outputs a sensing signal corresponding to an intensity of an external light;
• a backlight driver which receives the sensing signal to control an intensity of the internal light generated from the backlight unit;
• and
• a display panel driver driving the pixels arranged in the display panel, and
• wherein the display panel further comprises:
• a test circuit connected to an output node of the light sensor, which outputs a driving signal in response to the sensing signal output from the output node of the light sensor when the external light having a predetermined intensity is provided to the light sensor in order to test the light sensor, and
• pixels selected from the pixels which receive the driving signal from the test circuit to display a gray-scale corresponding to the driving signal during the test process of the light sensor.