GOA CIRCUIT WITH FORWARD-BACKWARD SCAN FUNCTION

• US 20170148403A1
• Filed: 05/21/2015
• Published: 05/25/2017
• Est. Priority Date: 04/27/2015
• Status: Active Grant

• Current Assignee: Shenzhen China Star Optoelectronics Technology Co., Ltd. (TCL Technology Group Corp.)
• Original Assignee: Shenzhen China Star Optoelectronics Technology Co., Ltd. (TCL Technology Group Corp.)
• Inventors: Dai, Chao
• Granted Patent: US 9,779,682 B2
• Time in Patent Office: Days
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: G09G 2310/0283 Arrangement of drivers for different directions of scanning
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 3/3677 suitable for active matrices only

Abstract

The present invention provides a GOA circuit with forward-backward scan function. In the GOA unit circuit of every stage, the pull-up controlling module comprises two thin film transistors respectively controlling the forward, backward scans. With proper received signals, as the thin film transistor controlling the forward scan is on, the GOA circuit performs forward scan from the GOA unit circuit of the first stage to the GOA unit circuit of the last stage, and as the thin film transistor controlling the backward scan is on, the GOA circuit performs backward scan from the GOA unit circuit of the last stage to the GOA unit circuit of the first stage. Thurs, the GOA circuit possessing functions of forward scan and backward scan at the same time can be achieved to expand the application field of the GOA circuit.

Claims

1. A GOA circuit with forward-backward scan function, comprising a plurality of GOA unit circuits which are cascade connected, and the GOA unit circuit of every stage comprises a pull-up controlling module, a pull-up module, a transmission module, a first pull-down module, a bootstrap capacitor module and a pull-down holding module;

N is set to be a positive integer and except the GOA unit circuit of the first and last stages, in the GOA unit circuit of the Nth stage;

the pull-up controlling module is employed to control the GOA circuit to perform forward scan or backward scan, and is electrically coupled to a first node and the pull-down holding module;

the pull-up controlling module at least comprises a thin film transistor for controlling the forward scan and a film transistor for controlling the backward scan, and a stage transfer at least coupled to a GOA unit circuit of the former N−

1th stage, a stage transfer at least coupled to a GOA unit circuit of the latter N+1th stage and a positive constant voltage source;

the pull-up module comprises;

a twenty-first thin film transistor, and a gate of the twenty-first thin film transistor is electrically coupled to the first node, and a source is electrically coupled to a Mth clock signal, and a drain is electrically coupled to a scan driving signal;

the transmission module comprises;

a twenty-second thin film transistor, and a gate of the twenty-second thin film transistor is electrically coupled to the first node, and a source is electrically coupled to the Mth clock signal, and a drain is electrically coupled to the stage transfer signal;

the first pull-down module is electrically coupled to the first node and a scan drive signal, and at least comprises one thin film transistor controlled by a M+2 clock signal;

the bootstrap capacitor module comprises a capacitor, and one end of the capacitor is electrically coupled to the first node, and the other end is electrically coupled to the scan drive signal;

the pull-down holding module at least comprises;

an inverter constructed by a plurality of thin film transistors, and an input end of the inverter is electrically coupled to the first node, and an output end is electrically coupled to a second node;

a forty-second thin film transistor, and a gate of the forty-second thin film transistor is electrically coupled to the second node, and a source is electrically coupled to the first node, and a drain is electrically coupled to a second negative constant voltage source;

a thirty-second thin film transistor, and a gate of the thirty-second thin film transistor is electrically coupled to the second node, and a source is electrically coupled to the scan drive signal, and a drain is electrically coupled to a first negative constant voltage source;

the clock signal comprise four clock signals;

a first clock signal, a second clock signal, a third clock signal and a fourth clock signal;

as the clock signal is the third clock signal, the M+2th clock signal is the first clock signal, and as the clock signal is the fourth clock signal, the M+2th clock signal is the second clock signal;

a duty ratio of the clock signal is 25/75;

a voltage level of the second negative constant voltage source is smaller than a voltage level of the first negative constant voltage source.

2. The GOA circuit with forward-backward scan function according to claim 1, wherein the pull-up controlling module comprises two thin film transistors:

an eleventh thin film transistor and a twelfth thin film transistor;

a gate of the eleventh thin film transistor receives the stage transfer signal of the GOA unit circuit of the former N−

1th stage, and a source receives the positive constant voltage source, and a drain is electrically coupled to the first node;

a gate of the twelfth thin film transistor receives a stage transfer signal of the GOA unit circuit of the latter N+1th stage, and a source receives the positive constant voltage source, and a drain is electrically coupled to the first node;

the eleventh thin film transistor is employed to control the forward scan, and the twelfth thin film transistor is employed to control the backward scan.

3. The GOA circuit with forward-backward scan function according to claim 2, wherein in the first stage connection of the GOA circuit with forward-backward scan function, the gate of the eleventh thin film transistor receives a scan activation signal, and the gate of the twelfth thin film transistor receives the stage transfer signal of the GOA unit circuit of the second stage, and the source of the twenty-first thin film transistor and the source of the twenty-second thin film transistor are electrically coupled to the first clock signal;

in the last stage connection of the GOA circuit with forward-backward scan function, the gate of the eleventh thin film transistor receives the stage transfer signal of the GOA unit circuit of the next stage to the last stage, and the gate of the twelfth thin film transistor receives the scan activation signal, and the source of the twenty-first thin film transistor and the source of the twenty-second thin film transistor are electrically coupled to the fourth clock signal.

4. The GOA circuit with forward-backward scan function according to claim 1, wherein the pull-up controlling module comprises an eleventh thin film transistor, a twelfth thin film transistor and a thirteenth thin film transistor;

a gate of the eleventh thin film transistor receives a forward scan control voltage, and a source receives the stage transfer signal of the GOA unit circuit of the former N−

1th stage, and a drain is electrically coupled to a gate of the thirteenth thin film transistor;

a gate of the twelfth thin film transistor receives a backward scan control voltage, and a source receives a stage transfer signal of the GOA unit circuit of the latter N+1th stage, and a drain is electrically coupled to a gate of the thirteenth thin film transistor;

the gate of the thirteenth thin film transistor is electrically coupled to the drain of the eleventh thin film transistor and the drain of the twelfth thin film transistor, and a source receives the positive constant voltage source, and a drain is electrically coupled to the first node;

the eleventh thin film transistor is combined with the forward scan control voltage to control the forward scan, and the twelfth thin film transistor is combined with the backward scan control voltage to control the backward scan;

in forward scan, the forward scan voltage level signal is positive high voltage level, and the backward scan voltage level signal is negative low voltage level;

in backward scan, the forward scan voltage level signal is negative low voltage level, and the backward scan voltage level signal is positive high voltage level.

5. The GOA circuit with forward-backward scan function according to claim 4, wherein in the first stage connection of the GOA circuit with forward-backward scan function, the source of the eleventh thin film transistor receives a scan activation signal, and the source of the twelfth thin film transistor receives the stage transfer signal of the GOA unit circuit of the second stage, and the source of the twenty-first thin film transistor and the source of the twenty-second thin film transistor are electrically coupled to the first clock signal;

in the last stage connection of the GOA circuit with forward-backward scan function, the source of the eleventh thin film transistor receives the stage transfer signal of the GOA unit circuit of the next stage to the last stage, and the source of the twelfth thin film transistor receives the scan activation signal, and the source of the twenty-first thin film transistor and the source of the twenty-second thin film transistor are electrically coupled to the fourth clock signal.

6. The GOA circuit with forward-backward scan function according to claim 1, wherein the first pull-down module comprises a thin film transistor:

a forty-first thin film transistor, and a gate of the forty-first thin film transistor is electrically coupled to a M+2th clock signal, and a source is electrically coupled to the first node, and a drain is electrically coupled to the scan drive signal.

7. The GOA circuit with forward-backward scan function according to claim 1, wherein the first pull-down module comprises two thin film transistors:

a forty-first thin film transistor and a fortieth thin film transistor;

a gate of the forty-first thin film transistor is electrically coupled to a M+2th clock signal, and a source is electrically coupled to a drain of the fortieth thin film transistor, and a drain is electrically coupled to the scan drive signal;

both a gate and a source of the fortieth thin film transistor are electrically coupled to the first node, and a drain is electrically coupled to the source of the fortieth thin film transistor.

8. The GOA circuit with forward-backward scan function according to claim 1, wherein the first pull-down module comprises two thin film transistors:

a forty-first thin film transistor and a fortieth thin film transistor;

a gate of the fortieth thin film transistor is electrically coupled to a M+2th clock signal, and a source is electrically coupled to the first node, and a drain is electrically coupled to a gate and a source of the forty-first thin film transistor;

both the gate and the source of the forty-first thin film transistor are electrically coupled to the drain of the fortieth thin film transistor, and a drain is electrically coupled to the scan drive signal.

9. The GOA circuit with forward-backward scan function according to claim 1, wherein the pull-down holding module further comprises:

a twenty-third thin film transistor, and a gate of the twenty-third thin film transistor is electrically coupled to the second node, and a source is electrically coupled to a second negative constant voltage source, and a drain is electrically coupled to the stage transfer signal.

10. The GOA circuit with forward-backward scan function according to claim 1, wherein the pull-down holding module comprises an inverter, a thirty-second thin film transistor, a forty-second thin film transistor, a seventy-fourth thin film transistor and a seventy-third thin film transistor;

a source of the forty-second thin film transistor is electrically coupled to a second negative constant voltage source via the seventy-fourth thin film transistor;

a gate of the seventy-fourth thin film transistor is electrically coupled to the second node, and a source is coupled to a second negative constant voltage source, and a drain is electrically coupled to the source of the forty-second thin film transistor and a source of the seventy-third thin film transistor;

a gate of the seventy-third thin film transistor is electrically coupled to the first node, and a source is electrically coupled to a drain of the seventy-fourth thin film transistor, and a drain is electrically coupled to the positive constant voltage source;

the inverter is a dual inverter, comprising;

a fifty-first thin film transistor, and both a gate and a source of the fifty-first thin film transistor are electrically coupled to the positive constant voltage source, and a drain is electrically coupled to a third node;

a fifty-second thin film transistor, and a gate of the fifty-second thin film transistor is electrically coupled to the first node, and a source is electrically coupled to the third node, and a drain is electrically coupled to a first negative constant voltage source or the second negative constant voltage source;

a fifty-third thin film transistor, and a gate of the fifty-third thin film transistor is electrically coupled to the third node, and a source is electrically coupled to the positive constant voltage source, and a drain is electrically coupled to the second node;

a fifty-fourth thin film transistor, and a gate of the fifty-fourth thin film transistor is electrically coupled to the first node, and a source is electrically coupled to the second node, and a drain is electrically coupled to a fourth node;

a sixty-third thin film transistor, and a gate of the sixty-third thin film transistor is electrically coupled to the third node, and a source is electrically coupled to the positive constant voltage source, and a drain is electrically coupled to the fourth node;

a sixty-fourth thin film transistor, and a gate of the sixty-fourth thin film transistor is electrically coupled to the first node, and a source is electrically coupled to the fourth node, and a drain is electrically coupled to the second negative constant voltage source;

wherein the fifty-first thin film transistor, the fifty-second thin film transistor, the fifty-third thin film transistor and the fifty-fourth thin film transistor construct a main inverter, and the sixty-third thin film transistor and the sixty-fourth thin film transistor construct an auxiliary inverter.

11. A GOA circuit with forward-backward scan function, comprising a plurality of GOA unit circuits which are cascade connected, and the GOA unit circuit of every stage comprises a pull-up controlling module, a pull-up module, a transmission module, a first pull-down module, a bootstrap capacitor module and a pull-down holding module;

N is set to be a positive integer and except the GOA unit circuit of the first and last stages, in the GOA unit circuit of the Nth stage;

the pull-up controlling module is employed to control the GOA circuit to perform forward scan or backward scan, and is electrically coupled to a first node and the pull-down holding module;

the pull-up controlling module at least comprises a thin film transistor for controlling the forward scan and a film transistor for controlling the backward scan, and a stage transfer at least coupled to a GOA unit circuit of the former N−

1th stage, a stage transfer at least coupled to a GOA unit circuit of the latter N+1th stage and a positive constant voltage source;

the pull-up module comprises;

a twenty-first thin film transistor, and a gate of the twenty-first thin film transistor is electrically coupled to the first node, and a source is electrically coupled to a Mth clock signal, and a drain is electrically coupled to a scan driving signal;

the transmission module comprises;

a twenty-second thin film transistor, and a gate of the twenty-second thin film transistor is electrically coupled to the first node, and a source is electrically coupled to the Mth clock signal, and a drain is electrically coupled to the stage transfer signal;

the first pull-down module is electrically coupled to the first node and a scan drive signal, and at least comprises one thin film transistor controlled by a M+2 clock signal;

the bootstrap capacitor module comprises a capacitor, and one end of the capacitor is electrically coupled to the first node, and the other end is electrically coupled to the scan drive signal;

the pull-down holding module at least comprises;

an inverter constructed by a plurality of thin film transistors, and an input end of the inverter is electrically coupled to the first node, and an output end is electrically coupled to a second node;

a forty-second thin film transistor, and a gate of the forty-second thin film transistor is electrically coupled to the second node, and a source is electrically coupled to the first node, and a drain is electrically coupled to a second negative constant voltage source;

a thirty-second thin film transistor, and a gate of the thirty-second thin film transistor is electrically coupled to the second node, and a source is electrically coupled to the scan drive signal, and a drain is electrically coupled to a first negative constant voltage source;

the clock signal comprise four clock signals;

a first clock signal, a second clock signal, a third clock signal and a fourth clock signal;

as the clock signal is the third clock signal, the M+2th clock signal is the first clock signal, and as the clock signal is the fourth clock signal, the M+2th clock signal is the second clock signal;

a duty ratio of the clock signal is 25/75;

a voltage level of the second negative constant voltage source is smaller than a voltage level of the first negative constant voltage source;

wherein the pull-up controlling module comprises two thin film transistors;

an eleventh thin film transistor and a twelfth thin film transistor;

a gate of the eleventh thin film transistor receives the stage transfer signal of the GOA unit circuit of the former N−

1th stage, and a source receives the positive constant voltage source, and a drain is electrically coupled to the first node;

a gate of the twelfth thin film transistor receives a stage transfer signal of the GOA unit circuit of the latter N+1th stage, and a source receives the positive constant voltage source, and a drain is electrically coupled to the first node;

the eleventh thin film transistor is employed to control the forward scan, and the twelfth thin film transistor is employed to control the backward scan;

wherein the first pull-down module comprises two thin film transistors;

a forty-first thin film transistor and a fortieth thin film transistor;

a gate of the fortieth thin film transistor is electrically coupled to a M+2th clock signal, and a source is electrically coupled to the first node, and a drain is electrically coupled to a gate and a source of the forty-first thin film transistor;

both the gate and the source of the forty-first thin film transistor are electrically coupled to the drain of the fortieth thin film transistor, and a drain is electrically coupled to the scan drive signal;

wherein the pull-down holding module further comprises;

a twenty-third thin film transistor, and a gate of the twenty-third thin film transistor is electrically coupled to the second node, and a source is electrically coupled to a second negative constant voltage source, and a drain is electrically coupled to the stage transfer signal.

12. The GOA circuit with forward-backward scan function according to claim 11, wherein in the first stage connection of the GOA circuit with forward-backward scan function, the gate of the eleventh thin film transistor receives a scan activation signal, and the gate of the twelfth thin film transistor receives the stage transfer signal of the GOA unit circuit of the second stage, and the source of the twenty-first thin film transistor and the source of the twenty-second thin film transistor are electrically coupled to the first clock signal;

in the last stage connection of the GOA circuit with forward-backward scan function, the gate of the eleventh thin film transistor receives the stage transfer signal of the GOA unit circuit of the next stage to the last stage, and the gate of the twelfth thin film transistor receives the scan activation signal, and the source of the twenty-first thin film transistor and the source of the twenty-second thin film transistor are electrically coupled to the fourth clock signal.