Lg Display Co., Ltd.

Hee-Won Ahn

Kyung-Joon Kwon

Dong-Woo Kim

Jung-Hwan Lee

Hee-Jung Hong

Si-Hoon Lee

Eui-Yeol Oh

Kyo-Hyuck Choo

Chang-Kyun Park

Dae-Ho Cho

Sung-Soo Kim

Disclosed herein is a local dimming driving method and device of a Liquid Crystal Display (LCD) device, which is capable of preventing color change due to gray scale saturation when data is compensated while enabling local dimming. The local dimming driving method of the LCD device includes detecting maximum values per pixel from input image data, analyzing the maximum values per pixel on a block-by-block basis, and determining local dimming values per block according to the analysis result, calculating a first gain value using the local dimming values per block, calculating a maximum gain value per pixel using the maximum value per pixel as a second gain value, selecting a smaller value of the first and second gain values as a final gain value, compensating the input image data using the final gain value, and controlling luminance of a backlight unit on the block-by-block basis using the local dimming value per block.

Local dimming driving method and device of liquid crystal display device

A liquid crystal display device capable of improving a contrast ratio and of reducing a halo phenomenon with low power consumption and a method for local dimming driving the same are disclosed. A method for local dimming driving a liquid crystal display includes determining a local dimming value for each of light-emitting blocks based on analyzing input image data by the unit of light-emitting block provided in a backlight unit; determining a halo degree by analyzing a total light quantity of black pixels having black gradations in the input image data; adjusting the number of spatial filtering repetitions based on the determined halo degree; compensating the local dimming value by performing spatial filtering for the local dimming value an adjusted number of times; and controlling brightness of the backlight unit for each of the blocks by using the compensated local dimming value.

Liquid crystal display device and method for local dimming driving using spatial filter of the same

A local dimming driving method of the LCD device includes divisionally driving all of a plurality of blocks of a backlight unit using a maximum luminance signal and measuring luminance per block, setting one of the plurality of blocks as a reference block, detecting luminance deviations between the reference block and the residual blocks, and setting an offset value per block for compensating for the detected luminance deviations per block, analyzing an input image in units of blocks corresponding to the plurality of blocks of a backlight unit respectively, detecting a representative value per block, and determining a dimming value per block according to the representative value per block, correcting the dimming value per block using the offset value per block, and controlling the luminance of the backlight unit on a block-by-block basis using the corrected dimming value per block.

The present invention provides method and device for driving local dimming in a liquid crystal display device which enables adaptive application of a gradation roll-off according to an image characteristic. The method for driving local dimming in a liquid crystal display device includes the steps of determining a local dimming value of each light emitting block by analyzing a received image data light emitting block by light emitting block of a backlight unit, producing a pixel compensating coefficient on a light quantity change of each pixel by using the local dimming value of each light emitting block, producing a required gradient value by compensating the received image data by using the pixel compensating coefficient, and producing maximum required gradient values for one frame and an average value of the maximum required gradient values for one frame, determining a roll-off end point of a gradient roll-off section according to the maximum required gradient value, and determining a roll-off starting point of the gradient roll-off section according to the average of the maximum required gradient values, setting a gradient change curve of the gradient roll-off section by using the roll-off starting point and end point, and producing a gain value of each pixel from the gradient change curve, and forwarding an output gradient value by correcting the required gradient value by using the gain value of each pixel.

Method and device for driving local dimming in liquid crystal display device

A driving method for local dimming of a Liquid Crystal Display (LCD) device and an apparatus using the same are disclosed. The driving method includes measuring light intensities at a plurality of sampling points by driving a light source of a backlight unit and storing the light intensity measurements as light intensity data of the sampling points in a memory, determining a local dimming value of each block by analyzing input image data on a block basis, detecting a pixel position of current input data, selecting a plurality of sampling points adjacent to the current pixel and the light intensity data of the sampling points from the memory, detecting light intensity data of the current pixel by linearly interpolating the light intensity data of the sampling points individually, calculating a gain value by a light intensity analysis based on the light intensity data of the current pixel and the local dimming value of each block, compensating the current input data using the gain value, and controlling luminance of the backlight unit on a block basis using the local dimming value of each block.

Driving method for local dimming of liquid crystal display device and apparatus using the same

Disclosed herein is a local dimming driving method and device of an LCD device, which is capable of minimizing luminance deviation at the same gray scale due to a dimming difference between blocks. The local dimming driving method of the LCD device includes 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, and controlling luminance of a backlight unit on a block-by-block basis using the local dimming value per block controlled by spatial filtering.

A method of driving a liquid crystal display device includes inputting source image data, each of which has one of m gray level values, wherein m is a natural number, defining T error data from the source image data, wherein the error data have top k gray level values, and T and k are a natural number, generating conversion image data having larger gray level values than the source image data using one having a largest gray level value from the source image data excluding the error data, inputting the conversion image data to a liquid crystal panel, controlling a brightness of a backlight unit in accordance with the conversion image data, forming a bitmap corresponding to the conversion image data, wherein the bitmap shows positional distribution of pixels with the error data, counting error areas by scanning the bitmap, wherein each of the error areas includes the predetermined number of the pixels having the error data, and controlling the T according to the number of the error.

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Gyeonggi-do, South Korea

Hee-Won Ahn