Apparatus and method for luminance control of liquid crystal display device
AssigneeLG Display Co., Ltd.
InventorsHee Jung Hong, Kyung Joon Kwon
Life of this patent
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Abstract
A luminance control apparatus of a liquid crystal display device (LCD) is presented. The LCD includes a liquid crystal display panel divided into areas, lamps, an arithmetic unit, and a lamp driver. Fewer lamps are present than the number of areas. The arithmetic unit scans pixels of each area, extracts a peak value of the gray level of pixels of the area, and calculates a maximum peak brightness value and an average value of the area. The lamp driver controls the brightness of the lamps in accordance with the average value and the maximum peak brightness value.
Claims19
A luminance control apparatus comprising:
- a liquid crystal display panel divided into a first number of division areas;
- a plurality of lamps divided into and driven using a second number of areas smaller than the first number of division areas;
- an arithmetic unit that extracts a peak value of a gray level of each pixel of the division area, and calculates a maximum peak brightness value and an average value in the division area;
- and
- a lamp driver that controls a pulse for supplying to the lamp in accordance with the average value and the maximum peak brightness value,
- wherein the lamp driver controls a pulse duty ratio of the pulse in accordance with the average value and the maximum peak brightness value, and
- wherein for each of the second number of areas, the pulse duty ratio is a ratio of the average value of each of the second number of areas to a total of the average values of all of the second number of areas.
A luminance control method comprising:
- irradiating a liquid crystal display panel having a first number of division areas with light from a plurality of lamps dividedly driven into a second number which is smaller than the first number;
- calculating a maximum peak brightness value and an average peak value of each of video pixels generated by designated areas of the liquid crystal display panel;
- re-arranging a division area of the liquid crystal display panel to correspond to each of lamp division areas;
- and
- controlling a pulse for supplying to the lamp to irradiate the liquid crystal display panel with light in accordance with the maximum peak brightness value and the average peak values,
- wherein a pulse duty ratio of the pulse in accordance with the average peak value and the maximum peak brightness value is controlled, and
- wherein for each of the second number of areas, the pulse duty ratio is a ratio of the average peak value of each of the second number of areas to a total of the average peak values of all of the second number of areas.
A luminance control apparatus comprising:
- a display panel having a plurality of pixels, the pixels divided into sets of pixels;
- a plurality of lamps supplying light to the display panel, each set of pixels associated with a lamp;
- and
- a control circuit that, for each set of pixels, determines a plurality of characteristics including at least two of:
- a peak value of a gray level of each pixel in the set of pixels, a maximum peak value of the gray levels in the set of pixels, an average peak value of the gray levels in the set of pixels and an average value of the gray levels in the set of pixels, and controls a pulse for supplying to the lamp associated with the set of pixels dependent on the plurality of characteristics,
- wherein the control circuit controls a pulse duty ratio of the pulse in accordance with the plurality of characteristics, and
- wherein for each set of pixels, the pulse duty ratio is a ratio of the average peak value of the set of pixels to a total of the average peak values of all of the sets of pixels.
Dependencies are inferred from the claim text.