Patent ID: 9349328
Filing Date: 2016-05-24
CPC Classification: G09G,H05B

Claim Text:
1. A backlight apparatus comprising: a plurality of light sources; and a control unit which drives the plurality of light sources at an identical driving frequency and which performs pulse-width modulation control for a turned-on period and a turned-off period of each of the light sources, wherein: the control unit is capable of setting a duty ratio between the turned-on period and the turned-off period for each of the light sources and each of driving cycles; the control unit sets the duty ratio, for at least two of the light sources respectively, so that a condition, in which one cycle period composed of one turned-on period and one turned-off period is N times the driving cycle, wherein N is an integer of not less than 1, is fulfilled, and the duty ratio is 0 or 1 in at least one driving cycle of N pieces of the driving cycles for constructing the one cycle period if N is not less than 2; and the control unit driving the frequency is a least common multiple of reciprocals of the one cycle periods of the plurality of light sources, and determines the duty ratios of the respective light sources so that the light source, which has the one cycle period shorter than that of the light source in which N is not less than 2, is in the turned-off period in at least a partial period of the turned-on period of the light source in which N is not less than 2. wherein the driving frequency is a least common multiple of reciprocals of the one cycle periods of the plurality of light sources.