Liquid crystal display having a function of selecting dot inversion and method of selecting dot inversion thereof
A liquid crystal display includes: a liquid crystal display panel including data lines and gate lines crossing each other; a timing controller that maps data of an input image to polarity patterns of 1-dot inversion and 2-dot inversion, counts the number of positive data and the number of negative data, determines whether any one of the positive data and negative data becomes dominant or not based on a difference between the counted numbers, and selects either one of the 1-dot and 2-dot inversions; a data driving circuit that converts the data of the input image into data voltages to be supplied to the data lines and inverts the polarity of the data voltages by the selected dot inversion; and a gate driving circuit that sequentially supplies gate pulses synchronized with the data voltages to the gate lines.
1. A liquid crystal display having a function of selecting dot inversion, the liquid crystal display comprising:
a liquid crystal display panel including data lines and gate lines crossing each other;
a timing controller that maps data of an input image to polarity patterns of 1-dot inversion and 2-dot inversion, counts the number of positive data and the number of negative data, determines whether any one of the positive data and negative data becomes dominant or not based on a difference between the counted numbers, and selects either one of the 1-dot and 2-dot inversions;
a data driving circuit that converts the data of the input image into data voltages to be supplied to the data lines and inverts the polarity of the data voltages by the selected dot inversion; and
a gate driving circuit that sequentially supplies gate pulses synchronized with the data voltages to the gate lines,
wherein, as a result of mapping the data of the input image to the polarity pattern of the 1-dot inversion, if the difference between the number of positive data and the number of negative data is less than a predetermined reference value, the timing controller drives the data driving circuit by the 1-dot inversion, and
as the result of mapping the data of the input image to the polarity pattern of the 1-dot inversion, if the difference between the number of positive data and the number of negative data is more than the predetermined reference value, the timing controller maps the data of the input image to the polarity pattern of the 2-dot inversion and re-calculates the difference between the number of positive data and the number of negative data, and if the difference is less than the predetermined reference value, the timing controller drives the data driving circuit by the 2-dot inversion.
2. The liquid crystal display of claim 1 , wherein the timing controller generates a polarity control signal that drives the data driving circuit by the 1-dot inversion and the 2-dot inversion, and
the polarity control signal is changed within either a vertical blank time or a horizontal blank time with respect to the dot inversion selected by the timing controller.
3. A method of selecting dot inversion of a liquid crystal display, the method comprising:
mapping data of an input image to polarity patterns of 1-dot inversion and 2-dot inversion and counting the number of positive data and the number of negative data;
selecting either one of the 1-dot and 2-dot inversions by determining whether any one of the positive data and negative data becomes dominant or not based on a difference between the number of positive data and the number of negative data;
converting the data of the input image into data voltages, inverting the polarity of the data voltages by the selected dot inversion, and supplying the data voltages to data lines of a liquid crystal display panel; and
sequentially supplying gate pulses synchronized with the data voltages to gate lines of the liquid crystal display panel,
wherein the selecting of either one of the 1-dot and 2-dot inversions by determining whether any one of the positive data and negative data becomes dominant or not based on the difference between the number of positive data and the number of negative data comprises:
as a result of mapping the data of the input image to the polarity pattern of the 1-dot inversion, if the difference between the number of positive data and the number of negative data is less than a predetermined reference value, driving the data driving circuit by the 1-dot inversion; and
as the result of mapping the data of the input image to the polarity pattern of the 1-dot inversion, if the difference between the number of positive data and the number of negative data is more than the predetermined reference value, mapping the data of the input image to the polarity pattern of the 2-dot inversion and re-calculating the difference between the number of positive data and the number of negative data, and if the difference is less than the predetermined reference value, driving the data driving circuit by the 2-dot inversion.
4. The method of claim 3 , further comprising:
generating a polarity control signal which is changed according to the selected dot inversion; and
controlling a data driving circuit outputting the data voltages by the polarity control signal.
5. The method of claim 4 , wherein the polarity control signal is changed within either a vertical blank time or a horizontal blank time with respect to the dot inversion selected by the timing controller.