Patent ID: 7746330

Claim:
A method of reducing noises for improving quality of display in a liquid crystal display (LCD) system, wherein the LCD system includes an LCD panel, at least one lamp for producing light to illuminate the LCD panel, and wherein in operation the LCD system is supplied with a video signal, a vertical synchronization signal and a horizontal synchronization signal, comprising the steps of: a. determining a lamp driving frequency for the at least one lamp responsive to the horizontal synchronization signal; and b. generating a lamp driving signal with the lamp driving frequency to be received by the at least one lamp for producing light responsive to the lamp driving signal, wherein the following formulae (1) and (2) are satisfied: f lamp = 2 ⁢ n - 1 m ⁢ H sync + δ ( 1 ) H sync / m ≥ δ ≥ 0 ( 2 ) where H sync is the frequency of the horizontal synchronization signal in unit of (Hz); f lamp is the lamp driving frequency for the lamp driving signal in unit of (Hz); m, n=1, 2, 3, . . . , an integer; and δ indicates the permissible error of the lamp driving frequency.