Liquid crystal display device and method of driving the same

1. A liquid crystal display device comprising:

a liquid crystal panel including a plurality of display blocks and adapted to display an image in response to image signals;

a plurality of light-emitting blocks adapted to emit light to the liquid crystal panel and corresponding to the plurality of display blocks;

a first look-up table including a normalized value; and

a timing controller adapted to receive the normalized value corresponding to each of the light-emitting blocks from the first look-up table and use the normalized value to provide an optical data signal corresponding to each of the light-emitting blocks,

wherein the normalized value is obtained by dividing an initial duty ratio corresponding to a brightness value by a duty ratio corresponding to a maximum gray level,

wherein the timing controller determines an initial brightness of each of the light-emitting blocks corresponding to the image signal, and determines an amplitude of the optical data signal on the basis of a ratio of the low-brightness light-emitting blocks,

wherein the ratio of the low-brightness light-emitting blocks corresponds to a ratio of a number of low-brightness light-emitting blocks having an initial brightness that is lower than a reference brightness to a number of high-brightness light-emitting blocks having an initial brightness that is higher than the reference brightness among the plurality of light-emitting blocks, and

wherein: the amplitude of the optical data signal is increased according to the ratio of the low-brightness light-emitting blocks, if the ratio of the low-brightness light-emitting blocks is more than a reference ratio; and the amplitude of the optical data signal is maintained without any change, if the ratio of the low-brightness light-emitting blocks is less than the reference ratio.

2. The liquid crystal display device of claim 1 , further comprising a second look-up table including a maximum duty ratio corresponding to the ratio of the low-brightness light-emitting blocks, wherein the timing controller is further adapted to receive the maximum duty ratio from the second look-up table and use the maximum duty ratio to determine a duty ratio of the optical data signal.

3. The liquid crystal display device of claim 2 , wherein the duty ratio of the optical data signal is determined by multiplying the normalized value supplied from the first look-up table by the maximum duty ratio supplied from the second look-up table.

4. The liquid crystal display device of claim 2 , wherein the timing controller includes:

a normalizing unit adapted to use the first look-up table to designate the normalized value corresponding to each of the light-emitting blocks;

an amplitude determining unit adapted to determine the amplitude of the optical data signal on the basis of the ratio of the low-brightness light-emitting blocks; and

a duty ratio determining unit adapted to receive the maximum duty ratio corresponding to the ratio of the low-brightness light-emitting blocks from the second look-up table, and multiply the normalized value of each of the light-emitting blocks by the maximum duty ratio to determine the duty ratio of the optical data signal.

5. The liquid crystal display device of claim 2 , wherein the timing controller is adapted to:

receive the normalized value corresponding to the initial brightness of each of the light-emitting blocks from the first look-up table, and designate the normalized value to each of the light-emitting blocks;

determine the amplitude of the optical data signal on the basis of the ratio of the low-brightness light-emitting blocks; and

multiply the normalized value of each of the light-emitting blocks by the maximum duty ratio corresponding to the ratio of the low-brightness light-emitting blocks to determine the duty ratio of the optical data signal.

6. The liquid crystal display device of claim 5 , further comprising a second look-up table including the maximum duty ratio corresponding to the ratio of the low-brightness light-emitting blocks, wherein the timing controller is adapted to receive the maximum duty ratio from the second look-up table and use the maximum duty ratio to determine the duty ratio of the optical data signal.

7. The liquid crystal display device of claim 1 , wherein the timing controller includes:

a boosting determining unit adapted to determine whether to increase the amplitude of the optical data signal on the basis of the ratio of the low-brightness light-emitting blocks;

a normalizing unit adapted to designate the normalized value corresponding to each of the light-emitting blocks using the first look-up table, according to the determination result of the boosting determining unit; and

a duty ratio determining unit adapted to multiply the designated normalized value of each of the light-emitting blocks by the maximum duty ratio corresponding to the ratio of the low-brightness light-emitting blocks to determine the duty ratio of the optical data signal.

8. The liquid crystal display device of claim 7 , further comprising a second look-up table including the maximum duty ratio corresponding to the ratio of the low-brightness light-emitting blocks, wherein the timing controller is adapted to receive the maximum duty ratio from the second look-up table and use the maximum duty ratio to determine the duty ratio of the optical data signal.

9. The liquid crystal display device of claim 1 , further comprising a backlight driver adapted to receive the optical data signal from the timing controller and apply a current corresponding to the optical data signal to each of the light-emitting blocks.

10. The liquid crystal display device of claim 9 , wherein:

the optical data signal includes red, green, and blue optical data signals; and

the backlight driver includes first to third backlight drivers that supply currents corresponding to the red, green, and blue optical data signals.

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

providing a liquid crystal panel that includes a plurality of display blocks and displays an image in response to image signals;

receiving normalized values from a first look-up table, emitting light to the liquid crystal panel, and designating the normalized values to a plurality of light-emitting blocks corresponding to the plurality of display blocks;

determining optical data signals using the normalized values;

determining an initial brightness of each of the light-emitting blocks corresponding to the image signal; and

determining an amplitude of an optical data signal on the basis of a ratio of the low-brightness light emitting blocks,

wherein the first look-up table includes the normalized value obtained by dividing an initial duty ratio corresponding to a brightness value by a duty ratio corresponding to a maximum gray level,

wherein the ratio of the low-brightness light-emitting blocks corresponds to a ratio of a number of low-brightness light-emitting blocks having an initial brightness that is lower than a reference brightness to a number of high-brightness light-emitting blocks having an initial brightness that is higher than the reference brightness among the plurality of light-emitting blocks, and

wherein: the amplitude of the optical data signal is increased according to the ratio of the low-brightness light-emitting blocks, if the ratio of the low-brightness light-emitting blocks is more than a reference ratio; and the amplitude of the optical data signal is maintained without any change, if the ratio of the low-brightness light-emitting blocks is less than the reference ratio.

12. The method of claim 11 , wherein the determining of the optical data signal includes receiving the maximum duty ratio from a second look-up table which includes a maximum duty ratio corresponding to the ratio of the low-brightness light-emitting blocks, and determining a duty ratio of the optical data signal using the maximum duty ratio.

13. The method of claim 12 , wherein the determining of the duty ratio of the optical data signal is carried out by multiplying the normalized value supplied from the first look-up table by the maximum duty ratio supplied from the second look-up table.

14. The method of claim 11 , further comprising:

receiving a normalized value corresponding to the initial brightness of each of the light-emitting blocks from the first look-up table, and designating the normalized value corresponding to each of the light-emitting blocks;

determining the amplitude of the optical data signal on the basis of the ratio of the low-brightness light-emitting blocks; and

multiplying the normalized value of each of the light-emitting blocks by the maximum duty ratio corresponding to the ratio of the low-brightness light-emitting blocks to determine the duty ratio of the optical data signal.

15. The method of claim 11 , wherein the optical data signal includes red, green, and blue optical data signals.