Method for dividing display area for local dimming, liquid crystal display device using the same, and method for driving the liquid crystal display device

A method for driving a Liquid Crystal Display (LCD) device,

• comprising analyzing data on a data analysis area basis using information about the data analysis areas set by a method for dividing a display area for local dimming
• modulating the data on a data analysis area basis according to a result of the analysis, and determining a local dimming value for each of the local dimming blocks according to the result of the analysis,
• wherein the method for dividing a display area for local dimming, comprises:
• determining an initial number of pixels per data analysis area and a total number of residual pixels using a resolution of the display area and a total number of data analysis areas equal to a total number of local dimming areas of a backlight unit;
• calculating a first residual pixel sum of a current data analysis area by adding the total number of residual pixels to a second residual pixel sum of a previous data analysis area, each time a data analysis area index increases;
• comparing the first residual pixel sum of the current data analysis area with the total number of data analysis areas and determining whether to assign a residual pixel to the current data analysis area according to a result of the comparison;
• calculating a second residual sum of the current data analysis area by subtracting the total number of data analysis areas from the first residual pixel sum of the current data analysis area and outputting the second residual sum of the current data analysis area as the second residual sum of the previous data analysis area for a next data analysis area, if a residual pixel is assigned to the current data analysis area;
• setting the first residual sum of the current data analysis area as the second residual sum of the current data analysis area and outputting the second residual sum of the current data analysis area as the second residual sum of the previous data analysis area for the next data analysis area, if a residual pixel is not assigned to the current data analysis area;
• and
• repeating the calculation of a first residual pixel sum of a current data analysis area, the determination as to whether to assign a residual pixel to the current data analysis area, and the outputting of a second residual pixel sum of the current data analysis area, until the data analysis area index is a last data analysis area index,
• wherein the determination of an initial number of pixels per data analysis area and a total number of residual pixels comprises:
• determining an integer obtained by diving the resolution by the total number of data analysis areas as the initial number of pixels per data analysis area;
• and
• determining the total number of residual pixels by calculating “the resolution-(the initial number of pixels per data analysis area)×(the total number of data analysis areas)”.

An Liquid Crystal Display (LCD) device, comprising:

• a backlight unit for projecting light;
• a liquid crystal panel for displaying an image using the light received from the backlight unit;
• a local dimming driver for analyzing data on a data analysis area basis using information about the data analysis areas set by a method for dividing a display area for local dimming, modulating the data on a data analysis area basis according to a result of the analysis, and determining a local dimming value for each of the local dimming blocks according to the result of the analysis;
• a panel driver for outputting the data received from the local dimming driver to the liquid crystal panel;
• and
• a backlight driver for controlling luminance of the backlight unit on a local dimming block basis according to the local dimming value of each local dimming block received from the local dimming driver,
• wherein the method for dividing a display area for local dimming, comprises:
• determining an initial number of pixels per data analysis area and a total number of residual pixels using a resolution of the display area and a total number of data analysis areas equal to a total number of local dimming areas of a backlight unit;
• calculating a first residual pixel sum of a current data analysis area by adding the total number of residual pixels to a second residual pixel sum of a previous data analysis area, each time a data analysis area index increases;
• comparing the first residual pixel sum of the current data analysis area with the total number of data analysis areas and determining whether to assign a residual pixel to the current data analysis area according to a result of the comparison;
• calculating a second residual sum of the current data analysis area by subtracting the total number of data analysis areas from the first residual pixel sum of the current data analysis area and outputting the second residual sum of the current data analysis area as the second residual sum of the previous data analysis area for a next data analysis area, if a residual pixel is assigned to the current data analysis area;
• setting the first residual sum of the current data analysis area as the second residual sum of the current data analysis area and outputting the second residual sum of the current data analysis area as the second residual sum of the previous data analysis area for the next data analysis area, if a residual pixel is not assigned to the current data analysis area;
• and
• repeating the calculation of a first residual pixel sum of a current data analysis area, the determination as to whether to assign a residual pixel to the current data analysis area, and the outputting of a second residual pixel sum of the current data analysis area, until the data analysis area index is a last data analysis area index
• wherein the determination of an initial number of pixels per data analysis area and a total number of residual pixels comprises:
• determining an integer obtained by diving the resolution by the total number of data analysis areas as the initial number of pixels per data analysis area;
• and
• determining the total number of residual pixels by calculating “the resolution-(the initial number of pixels per data analysis area)×(the total number of data analysis areas)”.