The quantity of light from a backlight is monitored by a first photodetector, and the environment on the part of a user is monitored by a second photodetector disposed in the rear of a liquid crystal panel, not on the front thereof. It is possible to exclude the influence of external light from the user...http://www.google.ca/patents/US7068333?utm_source=gb-gplus-sharePatent US7068333 - Liquid crystal display with photodetectors having polarizing plates mounted thereon and its correcting method
