Patent ID: 8648886
Filing Date: 2014-02-11
Classification: G09G

Abstract:
1. A liquid crystal display device comprising: a liquid crystal display panel configured to include a plurality of liquid crystal cell formed on regions which are defined by a plurality of gate lines and a plurality of data lines; a backlight unit configured to irradiate light on the liquid crystal display panel using a plurality of light emission diode arrays each with a plurality of light emission diodes; a first dimming signal generator configured to divide an external image data into a plurality of block image data and to generate first dimming signals corresponding to red, green, and blue data with each block image data; a second dimming signal generator configured to generate a second dimming signal corresponding to a brightness data with each block image data; a dimming mode controller configured to calculate a difference value between maximum and minimum grayscale values by analyzing histograms for the red, green, and blue data with each block data, to derive a dimming mode control signal from the difference value; a selector configured to select one of the first and second dimming signals in accordance with the dimming mode control signal from the dimming mode controller; and a light emission diode driver configured to drive the plurality of light emission diodes of each of the plural light emission diode arrays which correspond to a plural blocks, wherein the first dimming signal and the second dimming signal are applied to the selector, wherein the dimming mode control signal is generated from comparing a calculated gain value with a reference gain, wherein the gain value is calculated from the grayscale difference value, and wherein the gain value is calculated from equation 1: in equation 1, the parameter N has a grayscale value for the red, green, and blue pixel data which is accumulated the same as a reference accumulation value when one block of the red, green, and blue pixel data is sequentially accumulated from the red, green, and blue pixel data of the most significant grayscale level to the red green, and blue pixel data of the least significant grayscale level, the reference accumulation value being set to the red, green, and blue pixel data number corresponding to a range of 1˜5% of total red, green, and blue pixel data included in each of the block image data.