Patent ID: 8282259

Claim:
A display device comprising: a display unit; and a backlight unit for applying light to the display unit, the backlight unit comprising: a light source; a light-guide plate provided at the light source for guiding light emitted by the light source to the display unit, an optical sensor arranged to face the light-guide plate and having a photo detector for receiving light; a light-shielding portion that shields light that is otherwise incident to the photo detector from the periphery of the optical sensor, the light-shielding portion being provided around the photo detector; and a board provided on the optical sensor, wherein the light-guide plate has an extended portion, wherein the board is held to face the extended portion, and wherein the extended portion is arranged to extend out of the display area of the display unit, the extended portion having a recess formed in a thickness direction thereof, and the optical sensor is arranged within the recess and the photo detector is arranged to face a bottom of the recess for receiving light emitted from the bottom of the recess.