Patent ID: 8144108

Claim:
A liquid crystal display device comprising: an input unit inputting data corresponding to an image displayed on a liquid crystal panel; a backlight unit including a plurality of lamps illuminating light onto the liquid crystal panel; a histogram analyzing unit analyzing a histogram of input data from the input unit to generate a select signal according to a brightness state of the data; a data correcting unit correcting pixel data to be supplied to the liquid crystal panel using at least one of a plurality of gamma compensating characteristic curves according to the brightness state of the input data from the input unit; a liquid crystal panel driving unit driving the liquid crystal panel according to data corrected by the data correcting unit; a duty ratio determining unit generating a plurality of lamp-on signals having different duty ratios, respectively, according to the brightness state of the input data from the input unit; and a lamp driving unit generating a lamp driving voltage corresponding to the lamp-on signal output from the duty ratio determining unit to sequentially light on/off the plurality of lamps, wherein the histogram analyzing unit analyzes a histogram of the input data from the input unit to judge whether brightness changes, and compares an average brightness value of the input data with a first reference brightness values and a second reference brightness value corresponding to a condition set by a user in advance to generate first to fourth select signals as a result of the comparison when the brightness changes, wherein the second reference brightness value is larger than the first reference brightness value, wherein the data correcting unit applies different compensation ratios that depend on the gamma characteristic curves to the input data from the input unit to generate the corrected data, wherein the duty ratio determining unit comprises first to fourth lamp-on signal generators corresponding to the first to fourth select signals, respectively, wherein the duty ratio determining unit selects one of the first to fourth lamp-on signal generators according to the select signal provided from the histogram analyzing unit, the selected lamp-on signal generator supplies a lamp-on signal to the lamp driving unit, wherein the first to fourth lamp-on signals generated by the first to fourth lamp-on signal generators have a different duty ratio, respectively.