Liquid crystal display and driving method thereof

Patent metadata

Field	Value
Publication number	US-9589544-B2
Application number	US-5492108-A
Country	US
Kind code	B2
Filing date	Mar 25, 2008
Priority date	Apr 7, 2003
Publication date	Mar 7, 2017
Grant date	Mar 7, 2017

Abstract

A method of optimizing pixel signals for a liquid crystal display includes receiving the first, second and third pixel signals for the (n−1), (n) and (n+1)th frames. The first and second pixel signals are compared to determine if the second pixel signal requires overshooting or undershooting. The second and third pixel signals are compared to determine if the second pixel signal requires to be increased for pre-titling. The second pixel signal is compensated accordingly, thereby increasing liquid crystal response time.

First claim

What is claimed is:

1. A display apparatus comprising:
a driving device configured to:
use a lookup table that maps all grey levels of a first range to a corresponding color corrected gray scale signals in a second range, wherein each range comprises a same lower limit corresponding to a 0% pixel transmittance, the first range comprises a first upper limit corresponding to a full-white color, and the second range comprises a second upper limit lower than the first upper limit that corresponds to the full-white color;
compare a first pixel signal of the color corrected gray scale signals for an n-th frame with a gray level of a second pixel signal of the color corrected gray scale signals for an (n−i)-th frame and use the first pixel signal to generate a compensated first pixel signal;

a display panel configured to display an image based on the compensated first pixel signal; and
wherein the compensated first pixel signal has a voltage level higher than a voltage level at which the image has the first upper limit,
wherein a gray level of the compensated first pixel signal is higher than the second upper limit,
wherein each range is represented by a same number of bits.

2. The display apparatus of claim 1 , wherein the driving device comprises:
a converter configured to (a) receive the first and second pixel signals, the first and second pixel signals corresponding to first gray levels within a first grayscale range having an X number of gray levels, and (b) convert the first gray levels of the first and second pixel signals into second gray levels within a second grayscale range having a Y number of gray levels and at least one overshooting gray level,
wherein the at least one overshooting gray level has a voltage level higher than a voltage level of a highest gray level of the second grayscale range.

3. The display apparatus of claim 2 , wherein the driving device further comprises:
a compensator configured to determine if the second gray levels of the first and second pixel signals satisfy a predetermined condition and compensating the second gray level of the first pixel signal if the predetermined condition is satisfied.

4. The display apparatus of claim 3 , wherein the predetermined condition is satisfied if the second gray level of the second pixel signal corresponds to a first color and the second gray level of the first pixel signal corresponds to a second color substantially whiter than the first color.

5. The display apparatus of claim 4 , wherein the compensator is configured to increase the second gray level of the first pixel signal to the overshooting gray level to generate the compensated first pixel signal.

6. A display apparatus comprising:
a driving device configured to reduce an original gray level of an input pixel signal of a first voltage level to a reduced gray level using a lookup table that maps all grey levels of a first gray scale range to a corresponding gray level in a second grayscale range, wherein the first grayscale range comprises a first upper limit corresponding to a full-white color, and the second grayscale range comprises a second upper limit lower than the first upper limit that correspond to the full-white color, the original gray level corresponding to the first upper limit; and
a display panel configured to display a full-white color upon receipt of the pixel signal with the reduced gray level; and
wherein the driving device is configured to compare a gray level of a first pixel signal for an n−th frame with a gray level of a second pixel signal for an (n−i)-th frame to determine whether the first pixel signal needs to be compensated, apply the first pixel signal to the display panel when compensation is not needed during an image period, and apply a compensated first pixel signal at a second voltage level higher than the first voltage level to the display panel when compensation is needed during the same image period,
wherein each grayscale range is represented by a same number of bits.

7. The display apparatus of claim 6 , wherein the driving device determines that the first pixel signal needs to be compensated when the first pixel signal is the first voltage level and the second pixel signal is at a voltage level for driving the display panel with a 0% pixel transmittance.

8. The display apparatus of claim 6 , wherein the driving device comprises:
a converter configured to (a) receive the first and second pixel signals, the first and second pixel signals corresponding to first gray levels within a first grayscale range having an X number of gray levels, and (b) convert the first gray levels of the first and second pixel signals into second gray levels within a second grayscale range having a Y number of gray levels and at least one overshooting gray level,
wherein the at least one overshooting gray level has a voltage level higher than highest gray level of the second grayscale range.

Assignees

• Song Jang-Kun
• Park Dong-Won
• Samsung Display Co Ltd

Inventors

• Song Jang-Kun
• Park Dong-Won

Classifications

• G09G3/2011

  by amplitude modulation · CPC title

• G09G3/3696

  Generation of voltages supplied to electrode drivers · CPC title

• G09G3/2018

  by time modulation using two or more time intervals · CPC title

• G09G2310/06

  Details of flat display driving waveforms · CPC title

• G09G5/06

  using colour palettes, e.g. look-up tables · CPC title