Patent ID: 8803925

Claim:
A liquid crystal display, comprising: a liquid crystal display panel configured to display modulated data based on a frame frequency; light sources configured to generate light to be irradiated into the liquid crystal display panel; a scanning backlight controller configured to calculate a turn-on duty ratio of a pulse width modulation (PWM) signal for controlling turn-on and turn-off operations of the light sources; and a light source driver configured to: compare the calculated turn-on duty ratio of the PWM signal with a critical value; differently process the PWM signal according to a result of the comparing such that a frequency of the PWM signal is synchronized with the frame frequency; the turn-on duty ratio of the PWM signal is changed to a value corresponding to full operation of the PWM signal; an amplitude of the PWM signal is adjusted based on a changed degree of the turn-on duty ratio of the PWM signal; and subsequently sequentially drive the light sources along a data scanning direction of the liquid crystal display panel, wherein the scanning backlight controller comprises an input image analysis unit, a duty ratio calculation unit, and a data modulation unit, wherein the input image analysis unit is configured to: compute a cumulative distribution function of digital video data of an input image; calculate a frame representative value based on the cumulative distribution function, the calculation including a mean value and a mode value of the cumulative distribution function; determine a gain value based on the frame representative value; and supply the gain value to the duty ratio calculation unit and the data modulation unit, and wherein the duty ratio calculation unit is configured to calculate the PWM duty ratio based on the gain value received from the input image analysis unit.