Patent ID: 9646544
Date: 2017-05-09
CPC Classifications: G02F,G09G,H05B,Y02B

Claim:
1. A backlight module comprising: a pulse-width modulator configured to provide a pulse-width modulated (PWM) signal; a light-emitting diode (LED) array driver configured to alternate, based on the PWM signal, between forward biasing a LED array to backlight a liquid crystal display (LCD) and reverse biasing the LED array to sense an ambient light level; a bias generator configured to alternate, based on the PWM signal, between providing a forward bias voltage to the LED array driver and providing a reverse bias voltage to the LED array driver; and a brightness controller configured to modulate a duty-cycle of the PWM signal based on the ambient light level sensed by the LED array, wherein, before using the ambient light level sensed by the LED array to modulate the duty-cycle of the PWM signal, the brightness controller is configured to adjust the ambient light level sensed by the LED array based on a number of pixels of at least a portion of the LCD having a brightness that falls within one of a plurality of brightness ranges.