Gate driver and display device having the same

Patent metadata

Field	Value
Publication number	US-10553147-B2
Application number	US-201715718804-A
Country	US
Kind code	B2
Filing date	Sep 28, 2017
Priority date	Sep 30, 2016
Publication date	Feb 4, 2020
Grant date	Feb 4, 2020

Abstract

A display device comprises a pixel array, a timing controller, a Q node control signal input line, and a shift register. In the pixel array, data lines and gate lines are defined, and pixels are arranged in a matrix. The timing controller outputs a start signal and a first reset signal. The Q node control signal input line receives the start signal and the first reset signal. The shift register comprises a plurality of stages connected as a cascade, and sequentially supplies dummy gate pulses or gate pulses applied to the gate lines.

First claim

The invention claimed is:

1. A display device, comprising:
a pixel array where data lines and gate lines are defined and pixels are arranged in a matrix;
a timing controller that outputs a start signal and a first reset signal;
a Q node control signal input line that receives the start signal and the first reset signal; and
a shift register comprising a plurality of stages connected as a cascade and sequentially supplying dummy gate pulses or gate pulses applied to the gate lines, wherein each of the stages comprises:
a pull-up transistor that charges an output node connected to one of a source node or a drain node of the pull-up transistor using a clock signal applied to another one of the drain node or the source node of the pull-up transistor in response to a voltage at a Q node;
a first transistor that charges the Q node with a high-potential voltage in response to the start signal applied from the Q node control signal input line or a voltage at an output node of a preceding stage; and
a second transistor that discharges the Q node to a low-potential voltage in response to the first reset signal applied from the Q node control signal input line or a voltage at an output node of a succeeding stage, a high-potential voltage input line from which the high-potential voltage is applied being shifted to a low-potential voltage while the first reset signal is being applied.

2. The display device of claim 1 , wherein a frame is divided into an active period and a subsequent vertical blanking interval,
wherein the start signal is applied at an initial phase of the active period, and the first reset signal is applied at an end of the active period.

3. The display device of claim 1 , wherein the shift register includes:
first to nth stages respectively connected to n pixel lines (n being a natural number) on the pixel array; and
a first dummy stage preceding the first stage,
wherein the first dummy stage outputs a first dummy gate pulse in response to the start signal, and the first stage outputs a first gate pulse in response to the first dummy gate pulse.

4. The display device of claim 3 , further comprising a second dummy stage succeeding the nth stage,
wherein the second transistors of the first to nth stages each discharge the Q node thereof in response to the voltage at the output node of the succeeding stage, and the second transistor of the second dummy stage discharges the Q node thereof in response to the first reset signal.

5. The display device of claim 4 , wherein a frame is divided into an active period and a subsequent vertical blanking interval and the Q node control signal input line further receives a second reset signal from the timing controller within the vertical blanking interval, and
wherein the first to nth stages and the second dummy stage each further comprise a third transistor that discharges the Q node thereof to the low-potential voltage, in response to the second reset signal applied from the Q node control signal input line.

6. The display device of claim 5 , wherein the high-potential voltage input line maintains the low-potential voltage while the second reset signal is being applied.

7. A gate driver for a display device, comprising:
a Q node control signal input line that receives a start signal and a first reset signal; and
a shift register comprising a plurality of stages connected as a cascade and sequentially supplying dummy gate pulses or gate pulses applied to the gate lines, wherein each of the stages comprises:
a pull-up transistor that charges an output node connected to one of a source node or a drain node of the pull-up transistor using a clock signal applied to another one of the drain node or the source node of the pull-up transistor in response to a voltage at a Q node;
a first transistor that charges the Q node with a high-potential voltage in response to the start signal applied from the Q node control signal input line or a voltage at an output node of a preceding stage; and
a second transistor that discharges the Q node to a low-potential voltage in response to the first reset signal applied from the Q node control signal input line or a voltage at an output node of a succeeding stage, a high-potential voltage input line from which the high-potential voltage is applied being shifted to a low-potential voltage while the first reset signal is being applied.

8. The gate driver of claim 7 , wherein a timing frame of the display device includes an active period and a subsequent vertical blanking interval,
wherein the start signal is applied at a beginning of the active period, and the first reset signal is applied about an end of the active period.

9. The gate driver of claim 7 , wherein the shift register includes:
first to nth stages respectively connected to n pixel lines (n being a natural number) on a pixel array of the display device; and
a first dummy stage preceding the first stage,
wherein the first dummy stage outputs a first dummy gate pulse in response to the start signal, and the first stage outputs a first gate pulse in response to the first dummy gate pulse.

10. The gate driver of claim 9 , further comprising a second dummy stage succeeding the nth stage,
wherein the second transistors of the first to nth stages each discharge the Q node thereof in response to the voltage at the output node of the succeeding stage, and the second transistor of the second dummy stage discharges the Q node thereof in response to the first reset signal.

11. The gate driver of claim 10 , wherein a timing frame of the display device includes an active period and a subsequent vertical blanking interval and the Q node control signal input line further receives a second reset signal within the vertical blanking interval, and
wherein the first to nth stages and the second dummy stage each further include a third transistor that discharges the Q node thereof to the low-potential voltage, in response to the second reset signal applied from the Q node control signal input line.

12. The gate driver of claim 11 , wherein the high-potential voltage input line maintains the low-potential voltage while the second reset signal is being applied.

13. A method of driving a pixel array of a display device comprising:
charging a first dummy stage using a start signal and a first clock signal subsequent to the start signal to generate a first dummy output;
charging a first driving stage using the first dummy output and a second clock signal to generate a first driving output, the second clock signal being an inversion of the first clock signal;
discharging the first dummy stage using the first driving output;
charging a second driving stage using the first driving output and the first clock signal to generate a second driving output;
discharging the first driving stage using the second driving output;
charging a second dummy stage using a driving output of a last driving stage to generate a second dummy output;
discharging the last driving stage using the second dummy output; and
discharging the second dummy state using a first reset signal, the first reset signal being provided from a same signal line as the start signal.

14. The method of claim 13 , further comprising:
resetting the first driving stage, the second driving stage, the last driving stage and the second dummy stage using a second reset signal, the second reset signal being provided from the same signal line.

15. The method of claim 13 , wherein a timing frame of the display device includes an active period and a subsequent vertical blanking interval and the start signal is applied at an

Assignees

• Lg Display Co Ltd

Inventors

• Jang Hyunguk
• Heo Seungho

Classifications

• G09G3/20 Primary

  for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix {no fixed position being assigned to or needed to be assigned to the individual characters or partial characters} · CPC title

• G09G2310/08

  Details of timing specific for flat panels, other than clock recovery · CPC title

• G11C19/28

  using semiconductor elements (G11C19/14, G11C19/36 take precedence) · CPC title

• G09G2310/0286

  Details of a shift registers arranged for use in a driving circuit · CPC title

• G09G2310/0267

  Details of drivers for scan electrodes, other than drivers for liquid crystal, plasma or OLED displays · CPC title