Local dimming driving method and device of liquid crystal display device

A method of driving a liquid crystal display device, the method comprising:

• analyzing input image data in units of blocks and determining a local dimming value per block;
• performing spatial filtering with respect to the local dimming value per block;
• repeating spatial filtering by a predetermined repeat count;
• controlling luminance of a backlight unit on a block-by-block basis using the local dimming value per block controlled by spatial filtering;
• calculating a gain value using the local dimming value per block;
• compensating the input image data using the gain value;
• supplying the compensated data to a liquid crystal panel;
• and
• displaying the input image data by a combination of the luminance of the backlight unit controlled on the block-by-block basis and light transmittance controlled by the compensated data on the liquid crystal panel,
• wherein the repeat count of spatial filtering is previously set by:
• generating a light profile of a light source within the backlight unit, the light profile being obtained by measuring and regulating the quantity of light emitted according to a distance from the light source;
• determining a straightness level and a diffusion level of light from the light profile;
• and
• setting the repeat count of spatial filtering in proportion to the straightness level and diffusion level of the light.

A local dimming driving device of a liquid crystal display device, the local dimming driving device comprising:

• an image analyzer analyzing input image data in units of blocks corresponding to light emitting blocks of a backlight unit;
• a dimming value decider determining a local dimming value per block according to the analysis result of the image analyzer;
• a spatial filter performing spatial filtering with respect to the local dimming value per block from the dimming value decider, to control the local dimming value per block, and outputting the controlled local dimming value per block;
• and
• a counter counting an output count of the spatial filter and controlling an input/output path of the spatial filter such that the spatial filter repeatedly performs spatial filtering by a predetermined repeat count,
• wherein:
• a light profile of a light source within the backlight unit is generated,
• a straightness level and a diffusion level of light is determined from the light profile, and
• the repeat count of spatial filtering is set in proportion to the straightness level and diffusion level of the light, and
• wherein the light profile is obtained by measuring and regulating the quantity of light emitted according to a distance from the light source.

A liquid crystal display device, comprising:

• a local dimming driver analyzing an input image data, generating a local dimming value and compensating an input image data according to the analyzing result;
• a panel driver supplying the compensated data from the local dimming driver to a liquid crystal panel;
• a timing controller outputting the compensated data from the local dimming driver to the panel driver and controlling driving timing of the panel driver;
• a backlight unit including a plurality of light emitting blocks to irradiate light to the liquid crystal panel;
• and
• a backlight driver driving the light emitting blocks using the dimming value per block from the local dimming driver,
• wherein the local dimming driver comprises:
• an image analyzer analyzing input image data in units of blocks corresponding to light emitting blocks of a backlight unit,
• a dimming value decider determining a local dimming value per block according to the analysis result of the image analyzer,
• a spatial filter performing spatial filtering with respect to the local dimming value per block from the dimming value decider, to control the local dimming value per block, and to output the controlled local dimming value per block,
• a counter counting an output count of the spatial filter and controlling an input/output path of the spatial filter such that the spatial filter repeatedly performs spatial filtering by a predetermined repeat count,
• a gain value calculator calculating a gain value using the local dimming value per block from the dimming value decider, and
• a data compensator compensating the input image data using the gain value from the gain value calculator,
• wherein:
• a light profile of a light source within the backlight unit is generated,
• a straightness level and a diffusion level of light is determined from the light profile, and
• the repeat count of spatial filtering is set in proportion to the straightness level and diffusion level of the light, and
• wherein the light profile is obtained by measuring and regulating the quantity of light emitted according to a distance from the light source.