Liquid crystal display
View Patent ↗A liquid crystal display with multi-line inversion which reverses polarity of applied voltages every two or more rows for preventing the deterioration of liquid crystal. An LCD includes a data driver outputting analog gray voltages selected based on the image data to the data lines of the LC panel. The data driver includes a data line bias circuit biasing the data lines to an intermediate level voltage whenever displaying the pixels in one row. Accordingly, the amount of stored charges between the pixels in the rows with polarity inversion and the pixels in the rows without polarity inversion is reduced, and consequently, the luminance difference between the pixels in the rows with the polarity inversion. The application duration of the data signals for pixels in rows with polarity inversion is also extended, such that the difference in charge storage between the two rows is reduced.
1. A liquid crystal display, comprising:
a liquid crystal panel including a plurality of gate lines, a plurality of data lines intersecting the gate lines, and a plurality of pixels provided near the intersections of the gate lines and the data lines;
a timing controller receiving image data and synchronization signals from an external graphics source, performing format conversion for the image data and generating control signals required for driving the liquid crystal panel;
a voltage generator generating gray voltages and gate voltages required for the liquid crystal panel;
a gate driver sequentially scanning the gate lines of the liquid crystal panel by unit of one horizontal scanning period based on the gate voltages; and
a data driver arranges the image data from the timing controller corresponding to the data lines of the liquid crystal panel, selecting the gray voltages corresponding to the image data, and applying the selected voltages the pixels connected to the scanned the gate lines through the data lines,
wherein the data driver reverses the polarity of the gray voltages to be applied to the data lines of the liquid crystal panel by a predetermined number of rows, and biases the data lines to a voltage with a predetermined level before outputting the gray voltages to the pixels in each scanned row.
2. The liquid crystal display of claim 1 , wherein the data driver is controlled such that a duration for applying the gray voltages to the pixels in the rows with polarity inversion is longer than a duration for applying the gray voltages to the pixels in the rows without polarity inversion.
3. The liquid crystal display of claim 2 , wherein the data driver comprises a plurality of data driving ICs, each data driving IC assigned to a predetermined number of the data lines of the liquid crystal panel, and
each of the data driving ICs comprises,
a shift register shifting the image data from the timing controller and arranging the image data corresponding to the data lines;
a digital-to-analog converter selecting analog gray voltages corresponding to the image data for the data lines;
a latch outputting the gray voltages selected by the digital-to-analog converter to the liquid crystal panel in response to a predetermined control signal; and
data line bias circuit biasing the data lines of the liquid crystal panel to the voltage with the predetermined level whenever the latch outputs the gray voltages to the liquid crystal panel.
4. The liquid crystal display of claim 3 , wherein the voltage with the predetermined level includes a ground voltage.
5. The liquid crystal display of claim 3 , wherein the voltage with the predetermined level for positive polarity is different from the voltage with the predetermined level for negative polarity.
6. The liquid crystal display of claim 3 , wherein the predetermined control signal comprises a load signal controlling a timing for applying the gray voltages from the data driver to the data lines of the liquid crystal panel and a pulse timing of the load signal is determined by the timing controller.
7. The liquid crystal display of claim 1 , wherein the data driver comprises a plurality of data driving ICs, each data driving IC assigned to a predetermined number of the data lines of the liquid crystal panel, and
each of the data driving ICs comprises,
a shift register shifting the image data from the timing controller and arranging the image data corresponding to the data lines;
a digital-to-analog converter selecting analog gray voltages corresponding to the image data for the data lines;
a latch outputting the gray voltages selected by the digital-to-analog converter to the liquid crystal panel in response to a predetermined control signal; and
data line bias circuit biasing the data lines of the liquid crystal panel to the voltage with the predetermined level whenever the latch outputs the gray voltages to the liquid crystal panel.
8. The liquid crystal display of claim 7 , wherein the voltage with the predetermined level includes a ground voltage.
9. The liquid crystal display of claim 7 , wherein the voltage with the predetermined level for positive polarity is different from the voltage with the predetermined level for negative polarity.
10. The liquid crystal display of claim 7 , wherein the predetermined control signal comprises a load signal controlling a timing for applying the gray voltages from the data driver to the data lines of the liquid crystal panel and a pulse timing of the load signal is determined by the timing controller.