Liquid crystal display device including gate voltage output unit and method of driving the same
View Patent ↗A display device includes n th and (n+1) th gate lines in a display panel, wherein a pixel electrode of a pixel corresponding to the (n+1) th gate line overlaps the n th gate line; and a gate driver including a gate voltage output unit that outputs an on-level gate voltage and first and second off-level gate voltages to the n th gate line, wherein the on-level gate voltage is outputted during a charging period of the n th gate line, and the second off-level gate voltage is outputted during a charging period of the (n+1) th gate line.
1. A display device, comprising:
n th and (n+1) th gate lines in a display panel, wherein a pixel electrode of a pixel corresponding to the (n+1) th gate line overlaps the n th gate line; and
a gate driver including a gate voltage output unit that outputs an on-level gate voltage and first and second off-level gate voltages to the n th gate line, wherein the on-level gate voltage is outputted during a charging period of the n th gate line, and the second off-level gate voltage is outputted during a charging period of the (n+1) th gate line,
wherein the gate voltage output unit includes: an on-level transistor outputting the on-level gate voltage; first and second off-level transistors outputting the first and second off-level gate voltages; and a voltage follower connected to a source terminal of the second off-level transistor, and
wherein a source terminal of the first off-level transistor and an input terminal of the voltage follower are commonly connected to an off-level gate voltage LOG (line on glass) line.
2. The device according to claim 1 , wherein the first off-level gate voltage is outputted during a frame period excluding time assigned for the charging period of the n th gate line or the charging periods of the n th and (n+1) th gate lines.
3. The device according to claim 1 , further comprising a control portion turning on/off the on-level transistor and the first and second off-level transistors.
4. The device according to claim 3 , wherein the control portion includes first to third output terminals connected to gate terminals of the on-level transistor and the first and second off-level transistors, respectively.
5. The device according to claim 3 , wherein the control portion includes a first output terminal commonly connected to gate terminals of the on-level transistor and the first off-level transistor, and a second output terminal connected to a gate terminal of the second off-level transistor.
6. The device according to claim 3 , wherein the control portion is connected to a timing controller.
7. The device according to claim 6 , wherein the timing controller generates a plurality of signals that are transferred to the gate driver from a PCB (printed circuit board) via a plurality of LOG lines located along a peripheral portion of the display panel.
8. A method of driving a display device, comprising:
outputting through a gate voltage output unit of a gate driver an on-level gate voltage and first and second off-level gate voltages to a n th gate line which overlaps a pixel electrode of a pixel corresponding to the (n+1) th gate line,
wherein the on-level gate voltage is outputted during a charging period of the n th gate line, and the second off-level gate voltage is outputted during a charging period of the (n+1) th gate line,
wherein the gate voltage output unit includes: an on-level transistor outputting the on-level gate voltage; first and second off-level transistors outputting the first and second off-level gate voltages; and a voltage follower connected to a source terminal of the second off-level transistor, and
wherein a source terminal of the first off-level transistor and an input terminal of the voltage follower are commonly connected to an off-level gate voltage LOG (line on glass) line.
9. The method according to claim 8 , wherein the first off-level gate voltage is outputted during a frame period excluding time assigned for the charging period of the n th gate line or the charging periods of the n th and (n+1) th gate lines.
10. The method according to claim 8 , further comprising generating the second off-level gate voltage following an off-level gate voltage.
11. The method according to claim 10 , wherein the first off-level gate voltage is the off-level gate voltage.
12. The method according to claim 8 , further comprising:
generating a gate control signal, a data signal and a data control signal;
generating the on-level gate voltage and first and second off-level gate voltages using the gate control signal; and
supplying the data signal to the pixel electrode according to the data control signal during the charging period of the (n+1) th gate line.
13. A liquid crystal display device, comprising:
n th and (n+1) th gate lines in a liquid crystal panel, wherein a pixel electrode of a pixel corresponding to the (n+1) th gate line overlaps the n th gate line; and
an on-level transistor inputted with an on-level gate voltage and connected to the n th gate line;
a first off-level transistor inputted with an off-level gate voltage and connected to the n th gate line; and
a second off-level transistor inputted with an output voltage of a buffer and connected to the n th gate line,
wherein a source terminal of the first off-level transistor and an input terminal of the buffer are commonly connected to an off-level gate voltage LOG (line on glass) line.
14. The device according to claim 13 , wherein the on-level transistor is turned on during a charging period of the n th gate line, and the second off-level transistor is turned on during a charging period of the (n+1) th gate line.
15. The device according to claim 14 , wherein the first off-level transistor is turned on during a frame period excluding time assigned for the charging period of the n th gate line or the charging periods of the n th and (n+1) th gate lines.
16. The device according to claim 13 , wherein the buffer includes a voltage follower inputted with the off-level gate voltage.
17. The device according to claim 13 , further comprising a control portion turning on/off the on-level transistor and the first and second off-level transistors.
18. The device according to claim 17 , wherein the control portion includes first to third output terminals connected to gate terminals of the on-level transistor and the first and second off-level transistors, respectively.
19. The device according to claim 17 , wherein the control portion includes a first output terminal commonly connected to gate terminals of the on-level transistor and the first off-level transistor, and a second output terminal connected to a gate terminal of the second off-level transistor.
20. A driving circuit for a display device, comprising:
a timing controller outputting a gate control signal and an off-level voltage control signal;
an on-level transistor inputted with an on-level gate voltage;
a first off-level transistor inputted with an off-level gate voltage; and
a second off-level transistor inputted with an output voltage of a buffer,
wherein each of the on-level transistor, the first off-level transistor and the second off-level transistor is turned on according to the off-level voltage control signal, and
wherein a source terminal of the first off-level transistor and an input terminal of the buffer are commonly connected to an off-level gate voltage LOG (line on glass) line.
21. The driving circuit according to claim 20 , further comprising:
a level shifter receiving the gate control signal; and
an output buffer connected to the on-level transistor, the first off-level transistor and the second off-level transistor.