Liquid crystal display device performing dot inversion and method of driving the same
An LCD device for performing a dot inversion and a method of driving the same. A storage line is provided separately from a common electrode line so that a level of a storage voltage applied through the storage line can be shifted once per frame. As the storage voltage is shifted using the storage line, the polarity of a voltage applied to a pixel electrode of a liquid crystal is inverted. One such storage line is provided per line of the pixels and storage capacitors of the pixels disposed above and below the storage line are alternately connected to the storage line.
1 . A liquid crystal display (LCD) device comprising:
a pixel for displaying an image;
a scan line for supplying a scan signal to the pixel;
a data line crossing the scan line and for supplying a data signal to the pixel;
a common electrode line for supplying a common voltage to the pixel; and
a storage line disposed in parallel with the scan line and for performing a dot inversion.
2 . The LCD device of claim 1 , wherein the pixel comprises:
a thin film transistor (TFT) for performing an on/off operation in response to the scan signal and having a first electrode to receive the data signal and a second electrode;
a storage capacitor connected between the second electrode of the TFT and the storage line and for storing the data signal; and
a liquid crystal disposed between a pixel electrode connected to the second electrode of the TFT and a common electrode.
3 . The LCD device of claim 2 , wherein a storage voltage applied through the storage line alternates between a high level and a low level once per frame of the image.
4 . The LCD device of claim 3 , wherein the common voltage is maintained at a predetermined level for one frame of the image.
5 . The LCD device of claim 3 , wherein the data signal repeats a level shift once per frame of the image.
6 . The LCD device of claim 5 , wherein the storage capacitors of the pixels connected to the scan line are alternately connected to two storage lines placed above and below the pixels.
7 . A liquid crystal display (LCD) device comprising:
a thin film transistor (TFT) having a gate connected to a scan line, a first electrode connected to a data line, and a second electrode adapted to receive a data signal applied to the data line through a channel;
a liquid crystal disposed between a pixel electrode connected to the second electrode of the TFT and a common electrode of a common electrode line; and
a storage capacitor connected between the second electrode of the TFT and a storage line, and for storing the data signal.
8 . The LCD device of claim 7 , wherein a storage voltage applied through the storage line alternates between a high level and a low level once per frame of the image.
9 . The LCD device of claim 8 , wherein a common voltage applied to the common electrode is maintained at a predetermined level for one frame of the image.
10 . The LCD device of claim 8 , wherein the data signal repeats a level shift once per frame of the image.
11 . A method of driving a liquid crystal display (LCD) device, comprising:
turning on a thin film transistor (TFT) and storing a first data voltage applied through a data line as a first pixel voltage in a storage capacitor;
turning off the TFT and increasing the first pixel voltage according to a first storage voltage applied through a storage line provided separately from a common electrode line;
turning on the TFT and storing a second data voltage applied through the data line as a second pixel voltage in the storage capacitor; and
turning off the TFT and decreasing the second pixel voltage according to a second storage voltage applied through the storage line.
12 . The method of claim 11 , wherein the first data voltage is higher than the second data voltage.
13 . The method of claim 12 , wherein the first storage voltage is higher than the second storage voltage.
14 . The method of claim 13 , further comprising, after increasing the first pixel voltage according to the first storage voltage, maintaining the increased first pixel voltage.
15 . The method of claim 13 , wherein increasing the first pixel voltage according to the first storage voltage comprises:
rearranging an electric charge stored in the storage capacitor; and
applying the first storage voltage to the storage capacitor that stores the rearranged electric charge.
16 . The method of claim 15 , wherein decreasing the second pixel voltage according to the second storage voltage comprises:
rearranging an electric charge stored in the storage capacitor; and
applying the second storage voltage to the storage capacitor that stores the rearranged electric charge.