Liquid crystal display device and its driving method
View Patent ↗A Liquid Crystal Display (LCD) includes: a liquid crystal panel having liquid crystal cells divided by scan lines and data lines and arranged in a matrix shape; a data driving circuit to supply an image signal to the liquid crystal cells via the data lines; a scan driving circuit to sequentially select and scan the scan lines and to control an on/off state of switching elements arranged in each of the liquid crystal cells; a timing controller to drive both the data driving circuit and the scan driving circuit, based on an externally inputted signal; and a common electrode driving circuit to drive a common electrode of the liquid crystal panel. The common electrode driving circuit supplies a common voltage to the common electrode, the common voltage including a DC voltage for a first period of a first horizontal period (1H) and another voltage for a second remaining period of the first horizontal period (1H).
1. A Liquid Crystal Display (LCD) device, comprising:
a liquid crystal panel having liquid crystal cells divided by scan lines and data lines and arranged in a matrix shape;
a data driving circuit to supply an image signal to the liquid crystal cells via the data lines;
a scan driving circuit to sequentially select and scan the scan lines and to control an on/off state of switching elements arranged in each of the liquid crystal cells;
a timing controller to drive both the data driving circuit and the scan driving circuit, based on an externally inputted signal; and
a common electrode driving circuit to drive a common electrode of the liquid crystal panel and to supply a common voltage to the common electrode, the common voltage including a DC voltage maintained during a first period of a first horizontal period (1H) and another voltage applied during a second remaining continuous period of the first horizontal period (1H), with the another voltage continuously having an opposite polarity compared to the image signal which is simultaneously supplied by the data driving circuit.
2. The liquid crystal display device according to claim 1 , wherein the liquid crystal panel comprises:
a first substrate having the scan lines and the data lines arranged therein and having a switching element and a pixel electrode arranged adjacent to respective intersection points of their signal lines;
a second substrate arranged to face the first substrate and having the common electrode arranged on a front surface thereof and having Red (R), Green (G), and Blue (B) color filters arranged to respectively correspond to each of the pixel electrodes; and
a liquid crystal sealed between the first and second substrates.
3. The LCD device according to claim 2 , wherein a polarity of the common voltage supplied to the common electrode is reversed and supplied to be suitable for a reversed polarity of the voltage supplied to the pixel electrodes, an effective value of the voltage supplied to the liquid crystal remaining constant upon a polarity of the voltage supplied to the pixel electrodes being reversed.
4. The LCD device according to claim 1 , wherein a polarity of the common voltage is reversed and supplied in every second period of the first horizontal period (1H).
5. The LCD device according to claim 1 , wherein the common DC voltage comprises one half (½) of a sum of the common voltage and the pixel voltage supplied during the first horizontal period (1H).
6. The LCD device according to claim 1 , wherein the pixel voltage corresponding to the common voltage is supplied to be suitable for the second period of the first horizontal period (1H).
7. A method of driving a Liquid Crystal Display (LCD) device to display an image on a liquid crystal panel, the method comprising:
arranging scan lines and data lines on the liquid crystal panel;
arranging respective pixel electrodes on the liquid crystal panel in regions divided by the scan lines and data lines into a matrix;
arranging a common electrode on the liquid crystal panel;
interposing a liquid crystal layer between the common electrode and the pixel electrodes; and
supplying a common voltage to the common electrode, the common voltage including a DC voltage maintained during a first period of a first horizontal period (1H) and another voltage applied during a second remaining continuous period of the first horizontal period (1H), with the another voltage continuously having an opposite polarity compared to a voltage which is simultaneously applied on the pixel electrodes.
8. The method for driving an LCD device according to claim 7 , wherein a polarity of the common voltage supplied to the common electrode is reversed and supplied to be suitable for a reversed polarity of the voltage supplied to the pixel electrodes, an effective value of the voltage supplied to the liquid crystal remaining constant upon a polarity of the voltage supplied to the pixel electrodes being reversed.
9. The method for driving an LCD device according to claim 7 , wherein a polarity of the common voltage is reversed and supplied in every second period of the first horizontal period (1H).
10. The method for driving an LCD device according to claim 7 , wherein the common DC voltage comprises one half (½) of a sum of the common voltage and the pixel voltage supplied during the first horizontal period (1H).
11. The method for driving an LCD device according to claim 7 , wherein the pixel voltage corresponding to the common voltage is supplied to be suitable for the second period of the first horizontal period (1H).