SHIFT REGISTER, GATE DRIVER, AND DRIVING METHOD OF SHIFT REGISTER

• US 20190012973A1
• Filed: 08/04/2017
• Published: 01/10/2019
• Est. Priority Date: 01/18/2017
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd., Ordos Yuansheng Optoelectronics Co., Ltd. (BOE Technology Group Co., Ltd.)
• Original Assignee: BOE Technology Group Co., Ltd., Ordos Yuansheng Optoelectronics Co., Ltd. (BOE Technology Group Co., Ltd.)
• Inventors: Wang, Jiguo
• Granted Patent: US 10,636,372 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: G09G 2310/0267 Details of drivers for scan electrodes, other than drivers for liquid crystal, plasma or OLED displays
• CPC Class Codes: G09G 2310/0286 Details of a shift registers arranged for use in a driving circuit
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 3/3677 suitable for active matrices only
• CPC Class Codes: G11C 19/184 with field-effect transistors, e.g. MOS-FET
• CPC Class Codes: G11C 19/28 using semiconductor elements G11C19/14, G11C19/36 take precedence

Abstract

The present disclosure discloses a shift register, comprising: a first capacitor with a first terminal connected to a first pull-up node and a second terminal connected to a second pull-up node; a first thin-film transistor with a gate connected to the first pull-up node, a first electrode connected to the second pull-up node and a second electrode connected to a first clock signal input terminal; a second thin-film transistor with a gate connected to the second pull-up node, a first electrode connected to an output of the shift register, and a second electrode connected to a DC high level signal terminal; and an input control circuit The first capacitor, the first capacitor and the first thin-film transistor boost the voltage on the first pull-up node so as to make a clock signal inputted from the first clock signal input terminal pass to the second pull-up node.

Claims

1. A shift register comprising:

a first capacitor with a first terminal connected to a first pull-up node and a second terminal connected to a second pull-up node;

a first thin-film transistor with a gate connected to the first pull-up node, a first electrode connected to the second pull-up node, and a second electrode connected to a first clock signal input terminal;

a second thin-film transistor with a gate connected to the second pull-up node, a first electrode connected to an output of the shift register, and a second electrode connected to a DC high level signal terminal; and

an input control circuit connected to a first signal input terminal and a first signal control terminal, configured to control a voltage level of the first terminal of the first capacitor under the control of a first input signal inputted from the first signal input terminal and a first control signal inputted from the first signal control terminal,

wherein, the first capacitor and the first thin-film transistor boost the voltage on the first pull-up node so as to make a clock signal inputted from the first clock signal input terminal pass to the second pull-up node, and enable a high level signal inputted from the DC high level signal terminal to control the output of the shift register via the second thin-film transistor when the voltage level of the first terminal of the first capacitor is a turn-on voltage level.

2. The shift register according to claim 1, further comprising:

a second capacitor with a first terminal connected to a first pull-down node and a second terminal connected to a DC low level signal terminal;

a third thin-film transistor with a first electrode connected to the first pull-down node, and a gate and a second electrode connected with each other and to a second clock signal input terminal;

a fourth thin-film transistor with a first electrode connected to the DC low level signal terminal, a second electrode connected to the first pull-up node, and a gate connected to the first pull-down node;

a fifth thin-film transistor with a first electrode connected to the DC low level signal terminal and a second electrode connected to the first electrode of the second thin-film transistor; and

a potential-stabilizing unit with a first input terminal connected to the first pull-down node, a second input terminal connected to the first pull-up node, and an output terminal connected to a gate of the fifth thin-film transistor and used as a second pull-down node, the potential-stabilizing unit being configured to enable, according to the potential of the first pull-down node and the potential of the first pull-up node, the second pull-down node to output a more stable potential than that output by the first pull-down node, so as to control the output of the shift register GOA via the fifth thin-film transistor.

3. The shift register according to claim 2, wherein the potential-stabilizing unit comprises:

a sixth thin-film transistor with a first electrode connected to the second pull-down node, and a gate and a second electrode connected with each other and used as the first input terminal of the potential-stabilizing unit;

a seventh thin-film transistor with a gate used as the second input terminal of the potential-stabilizing unit, a first electrode connected to a DC low level signal terminal, and a second electrode connected to the second pull-down node; and

a third capacitor with a first terminal connected to the second pull-down node and a second terminal connected to the DC low level signal terminal.

4. The shift register according to claim 3, wherein the input control circuit comprises:

an eighth thin-film transistor with a gate connected to the first signal input terminal, a first electrode connected to the first pull-up node, and a second electrode connected to the first signal control terminal, and configured to charge the first capacitor under control of the first input signal inputted from the first signal input terminal and the first control signal inputted from the first signal control terminal; and

a ninth thin-film transistor with a gate connected to a second signal input terminal, a first electrode connected to a second signal control terminal, and a second electrode connected to the first pull-up electrode and the first electrode of the eighth thin-film transistor and configured to pull down the first pull-down node to a low level under the control of a second input signal inputted from the second signal input terminal and a second control signal inputted from the second signal control terminal.

5. The shift register according to claim 4, wherein,

when the first control signal inputted from the first signal control terminal is at a high level and the second control signal inputted from the second signal control terminal is at a low level, the shift register performs forward scan;

and

when the first control signal inputted from the first signal control terminal is at a low level and the second control signal inputted from the second signal control terminal is at a high level, the shift register performs reverse scan.

6. The shift register according to claim 4, further comprising:

a tenth thin-film transistor with a gate connected to the first pull-up node, a first electrode connected to the DC low level signal terminal, and a second electrode connected to the first pull-down node; and

an eleventh thin-film transistor with a first electrode connected to the DC low level signal terminal, a second electrode connected to the second pull-up node, and a gate connected to the first pull-down node.

7. The shift register according to claim 6, wherein,

when the clock signal inputted from the first clock signal input terminal is at a high level, the clock signal inputted from the second clock signal input terminal is at a low level;

and

when the clock signal inputted from the second clock signal input terminal is at a high level, the clock signal inputted from the first clock signal input terminal is at a low level.

8. The shift register according to claim 6, wherein, in a state where the first control signal inputted from the first signal control terminal is at a high level and the second control signal inputted from the second signal control terminal is at a low level:

when the first input signal inputted from the first signal input terminal is at a high level, the clock signal inputted from the first clock signal input terminal is at a low level and the clock signal inputted from the second clock signal input terminal is at a high level, the first pull-up node becomes a high level, the first thin-film transistor is turned on, the second pull-up node and the clock signal inputted from the first clock signal input terminal remain at a low level, the second thin-film transistor is turned off, and the output of the shift register remains at a low level; and

the tenth thin-film transistor is turned on, the first pull-down node is connected to the DC low level signal terminal, the second capacitor is discharged, the potential of the first pull-down node is pull down to a low level, the eleventh thin-film transistor is turned off, the seventh thin-film transistor is turned on, the second pull-down node is connected to the DC low level signal terminal, the third capacitor is discharged, the potential of the second pull-down node is pull down to the low level, and the fifth thin-film transistor is turned off.

9. The shift register according to claim 8, wherein, when the first input signal inputted from the first signal input terminal is at a low level, the clock signal inputted from the first clock signal input terminal is at a high level and the clock signal inputted from the second clock signal input terminal is at a low level, the eighth thin-film transistor is turned off, the first capacitor holds the high level of the first pull-up node, the voltage of the first pull-up node varies with the clock signal inputted from the first clock signal input terminal and causes the first thin-film transistor to remain being turned on, while the voltage of the second pull-up node varies with the clock signal inputted from the first clock signal input terminal and becomes a high level, the second thin-film transistor is turned on, and the output of the shift register is at a high level.

10. The shift register according to claim 9, wherein, when the second input signal inputted from the second signal input terminal is at a high level, the clock signal inputted from the first clock signal input terminal is at a low level, and the clock signal inputted from the second clock signal input terminal is at a high level, the ninth thin-film transistor is turned on, the first capacitor is discharged via the ninth thin-film transistor, the first pull-up node becomes a low level, the first thin-film transistor is turned off, the third thin-film transistor is turned on, the high level signal inputted from the second clock signal input terminal charges the second capacitor via the third thin-film transistor, the first pull-down node becomes a high level, the fourth thin-film transistor is turned on, so as to further ensure that the potential of the first pull-up node is pulled down, the eleventh thin-film transistor is turned on, the second pull-up node is pulled down to a low level, the second thin-film transistor is turned off, the high level of the first pull-down node charges the third capacitor via the sixth thin-film transistor, the second pull-down node becomes a high level, the fifth thin-film transistor is turned on, and the output of the shift register becomes a low level.

11. A gate driver, comprising multiple cascaded shift registers according to claim 1, wherein, for a shift register in a certain stage, the first input signal inputted from the first signal input terminal is a signal output from the gate driver of the previous stage, and the second input signal inputted from the second signal input terminal is a signal output from the gate driver of the next stage.

14. A driving method of a shift register according to claim 4, comprising:

applying a high level signal on the first clock signal input terminal, applying a low level signal on the second clock signal input terminal, applying a high level signal on the first signal input terminal, and applying a low level signal on the second signal input terminal at a time t1;

applying a low level signal on the first clock signal input terminal, applying a high level signal on the second clock signal input terminal, applying a low level signal on the first signal input terminal, and applying a low level signal on the second signal input terminal at a time t2 which is later than the time t1 by ½

cycle of the signal inputted from the first clock signal input terminal; and

applying a high level signal on the first clock signal input terminal, applying a low level signal on the second clock signal input terminal, applying a low level signal on the first signal input terminal, and applying a high level signal on the second signal input terminal at a time t3 which is later than time t2 by ½

cycle of the signal inputted from the first clock signal input terminal.

15. The driving method of claim 14, wherein:

when the first control signal inputted from the first signal control terminal is at a high level and the second control signal inputted from the second signal control terminal is at a low level, the shift register performs forward scan; and

when the first control signal inputted from the first signal control terminal is at a low level and the second control signal inputted from the second signal control terminal is at a high level, the shift register performs reverse scan.

16. The driving method of claim 14, wherein:

when the clock signal inputted from the first clock signal input terminal is at a high level, the clock signal inputted from the second clock signal input terminal is at a low level; and

when the clock signal inputted from the second clock signal input terminal is at a high level, the clock signal inputted from the first clock signal input terminal is at a low level.

17. The driving method of claim 14, wherein, in a state where the first control signal inputted from the first signal control terminal is at a high level and the second control signal inputted from the second signal control terminal is at a low level:

when the first input signal inputted from the first signal input terminal is at a high level, the clock signal inputted from the first clock signal input terminal is at a low level and the clock signal inputted from the second clock signal input terminal is at a high level, the first pull-up node becomes a high level, the first thin-film transistor is turned on, the second pull-up node and the clock signal inputted from the first clock signal input terminal remain at a low level, the second thin-film transistor is turned off, the output of the shift register remains at a low level; and

the tenth thin-film transistor is turned on, the first pull-down node is connected to the DC low level signal terminal, the second capacitor is discharged, the potential of the first pull-down node is pull down to a low level, the eleventh thin-film transistor is turned off, the seventh thin-film transistor is turned on, the second pull-down node is connected to the DC low level signal terminal, the third capacitor is discharged, the potential of the second pull-down node is pull down to the low level, and the fifth thin-film transistor is turned off.

18. The driving method according to claim 14, wherein, in a state where the first control signal inputted from the first signal control terminal is at a high level and the second control signal inputted from the second signal control terminal is at a low level:

when the first input signal inputted from the first signal input terminal is at a low level, the clock signal inputted from the first clock signal input terminal is at a high level and the clock signal inputted from the second clock signal input terminal is at a low level, the eighth thin-film transistor is turned off, the first capacitor holds the high level of the first pull-up node, the voltage of the first pull-up node varies with the clock signal inputted from the first clock signal input terminal and causes the first thin-film transistor to remain being turned on, while the voltage of the second pull-up node varies with the clock signal inputted from the first clock signal input terminal and becomes a high level, the second thin-film transistor is turned on, and the output of the shift register is at a high level.

19. The driving method according to claim 14, wherein, when the second input signal inputted from the second signal input terminal is at a high level, the clock signal inputted from the first clock signal input terminal is at a low level, and the clock signal inputted from the second clock signal input terminal is at a high level, the ninth thin-film transistor is turned on, the first capacitor is discharged via the ninth thin-film transistor, the first pull-up node becomes a low level, the first thin-film transistor is turned off, the third thin-film transistor is turned on, the high level signal inputted from the second clock signal input terminal charges the second capacitor via the third thin-film transistor, the first pull-down node becomes a high level, the fourth thin-film transistor is turned on, so as to further ensure that the potential of the first pull-up node is pulled down, the eleventh thin-film transistor is turned on, the second pull-up node is pulled down to a low level, the second thin-film transistor is turned off, the high level of the first pull-down node charges the third capacitor via the sixth thin-film transistor, the second pull-down node becomes a high level, the fifth thin-film transistor is turned on, and the output of the shift register becomes a low level.

12. (canceled)

13. (canceled)