Shift register and display device including the same

• US 8,107,586 B2
• Filed: 03/11/2005
• Issued: 01/31/2012
• Est. Priority Date: 03/12/2004
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Shin, Kyong-Ju, Chae, Chong-Chul, Hong, Mun-Pyo, Park, Cheol-Woo, Roh, Nam-Seok
• Primary Examiner(s): Lam, Tuan T
• Application Number:
  US11/078,985
• Publication Number:
  US 20050201508A1
• Time in Patent Office: 2,517 Days
• Field of Search: None
• US Class Current: 377/64
• CPC Class Codes: G09G 2310/0281 Arrangement of scan or data electrode driver circuits at the periphery of a panel not inherent to a split matrix structure
• CPC Class Codes: G09G 2310/0286 Details of a shift registers arranged for use in a driving circuit
• CPC Class Codes: G09G 2320/0223 Compensation for problems related to R-C delay and attenuation in electrodes of matrix panels, e.g. in gate electrodes or on-substrate video signal electrodes
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/3677 suitable for active matrices only
• CPC Class Codes: G11C 19/28 using semiconductor elements G11C19/14, G11C19/36 take precedence

Abstract

A shift register comprises stages connected to each other, in which each stage generates an output signal in response to any one of clock signals and an output from each of two different stages. Each clock signal has a duty ratio of less than 50% and a different phase from each of the other clock signals. A display device includes pixels, signal lines, and first and second shift registers each having stages connected to each other and generating output signals to signal lines. Each stage includes a set terminal, a reset terminal, a clock terminal, and first and second output terminals.

Claims

1. A shift register comprising a plurality of stages, wherein stages of the plurality of stages are connected to each other and a current stage thereof generates an output signal in response to any one of a plurality of clock signals,

wherein each of the stages comprises:

a driving unit which charges to a predetermined voltage in response to one of an output start signal and an output signal of a previous stage, and which generates the output signal in response to any one of the clock signals; and

a discharge unit which discharges the predetermined voltage in response to an output signal of a next stage,

wherein the driving unit comprises;

an input unit which outputs a first voltage in response to one of the output start signal and an output signal of the previous stage; and

an output unit which charges to the first voltage and generates the output signal in response to any one of the clock signals,

wherein each of the clock signals having a duty ratio of less than 50% and a different phase from each of the other clock signals,

wherein the output signal of the output unit is transmitted to a gate line and the next stage,

wherein each of high levels of the clock signals do not overlap each other, and

wherein the clock signals for some stages disposed on left side of the panel or the other stages disposed on right side of the panel have high value with a frequency of every 4 horizontal periods.

2. The shift register of claim 1, wherein the discharge unit outputs a second voltage to the output unit in response to the output signal of the next stage to discharge from the first voltage to the second voltage.

3. The shift register of claim 2, wherein the output unit outputs the second voltage as the output signal.

4. The shift register of claim 1, wherein each stage has a set terminal, a reset terminal, a first output terminal and a second output terminal, and

the input unit comprises a first switching element connected between the first voltage and a first point of contact and having a control terminal connected to the set terminal, and

the output assistant unit comprises:

a second switching element connected between the first voltage and a second point of contact; and

a third and a fourth switching elements connected in series between the first voltage and the second voltage,

wherein a control terminal of the second switching element is connected to a point of contact between the third and the fourth switching elements, and the discharge unit comprises;

a fifth and a sixth switching elements connected in parallel between the first point of contact and the second voltage; and

a seventh and a eighth switching elements connected in parallel between the second point of contact and the second voltage,

wherein a control terminal of the fifth switching element is connected to the reset terminal, and a control terminal of the sixth switching element is connected to the second point of contact, and a control terminal of the seventh switching element is connected to the first point of contact, and a control terminal of the eighth switching element is connected to the set terminal, and

the output unit comprises;

a ninth switching element, a tenth switching element, an eleventh switching element and a twelfth switching element, the ninth and tenth switching elements being connected in series between the clock terminal and the second voltage, and the eleventh and twelfth switching elements being connected in series between the clock terminal and the second voltage; and

a first capacitor and a second capacitor connected between the first point of contact and the first and second output terminals, respectively,

wherein control terminals of the ninth and the eleventh switching elements are connected to the first point of contact and control terminals of the tenth and the eleventh switching elements are connected to the second point of contact,

wherein the first output terminal is connected to a point of contact between the ninth and tenth switching elements, and the second output terminal is connected to a point of contact between the eleventh and twelfth switching elements.

5. The shift register of claim 4, wherein the first to twelfth switching elements comprise amorphous silicon.

6. The shift register of claim 1, wherein each stage has a set terminal, a reset terminal, a first output terminal and a second output terminal, and

the input unit comprises a first switching element connected between the first voltage and a first point of contact and having a control terminal connected to the set terminal, and

the output assistant unit comprises:

a second switching element connected between the first voltage and a second point of contact; and

a third and a fourth switching elements connected in series between the first voltage and the second voltage,

wherein a control terminal of the second switching element is connected to a point of contact between the third and the fourth switching elements, and the discharge unit comprises;

a fifth and a sixth switching elements connected in parallel between the first point of contact and the second voltage; and

a seventh and a eighth switching elements connected in parallel between the second point of contact and the second voltage,

wherein a control terminal of the fifth switching element is connected to the reset terminal, and a control terminal of the sixth switching element is connected to the second point of contact, and a control terminal of the seventh switching element is connected to the first point of contact, and a control terminal of the eighth switching element is connected to the set terminal, and

the output unit comprises;

a ninth switching element, a tenth switching element, an eleventh switching element and a twelfth switching element, the ninth and tenth switching elements being connected in series between the clock terminal and the second voltage, and the eleventh and twelfth switching elements being connected in series between the clock terminal and the second voltage; and

a first capacitor and a second capacitor connected between the first point of contact and the first and second output terminals, respectively,

wherein control terminals of the ninth and the eleventh switching elements are connected to the first point of contact and control terminals of the tenth and the eleventh switching elements are connected to the second point of contact,

wherein the first output terminal is connected to a point of contact between the ninth and tenth switching elements, and the second output terminal is connected to a point of contact between the eleventh and twelfth switching elements.

7. The shift register of claim 6, wherein the first to twelfth switching elements comprise amorphous silicon.

8. A shift register comprising a plurality of stages, wherein some stages of the plurality of stages are disposed on left side of a panel and the other stages of the plurality of stages are disposed on right side of the panel,

wherein each of the stages comprises:

a driving unit which charges to a predetermined voltage in response to one of an output start signal and an output signal of a previous stage, and which generates the output signal in response to any one of the clock signals; and

a discharge unit which discharges the predetermined voltage in response to an output signal of a next stage,

wherein the driving unit comprises;

an input unit which outputs a first voltage in response to one of the output start signal and an output signal of the previous stage; and

an output unit which charges to the first voltage and generates the output signal in response to any one of the clock signals,

wherein some stages disposed on left side of the panel are connected to each other and the other stages disposed on right side of the panel are connected to each other,

wherein each of the clock signals having a duty ratio of less than 50% and a different phase from each of the other clock signals,

wherein some stages disposed on left side of the panel and the other stages disposed on right side of the panel are alternatively connected to gate lines, and

wherein the clock signals for some stages disposed on left side of the panel or the other stages disposed on right side of the panel have high value with a frequency of every 4 horizontal periods.

9. The shift register of claim 8, wherein the discharge unit outputs a second voltage to the output unit in response to the output signal of the next stage to discharge from the first voltage to the second voltage.

10. The shift register of claim 9, wherein the output unit outputs the second voltage as the output signal.

11. The shift register of claim 8, wherein each of high values of the clock signals do not overlap each other.

12. A shift register comprising a plurality of stages, wherein some stages of the plurality of stages are disposed on left side of a panel and the other stages of the plurality of stages are disposed on right side of the panel,

wherein each of the stages comprises:

a driving unit which charges to a predetermined voltage in response to one of an output start signal and an output signal of a previous stage, and which generates the output signal in response to any one of the clock signals; and

a discharge unit which discharges the predetermined voltage in response to an output signal of a next stage,

wherein the driving unit comprises;

an input unit which outputs a first voltage in response to one of the output start signal and an output signal of the previous stage; and

an output unit which charges to the first voltage and generates the output signal in response to any one of the clock signals,

wherein some stages disposed on left side of the panel are connected to each other and the other stages disposed on right side of the panel are connected to each other,

wherein the output signal of the output unit is transmitted to a gate line and the next stage;

wherein some stages disposed on left side of the panel and the other stages disposed on right side of the panel are alternatively connected to gate lines, and

wherein the clock signals for some stages disposed on left side of the panel or the other stages disposed on right side of the panel have high value with a frequency of every 4 horizontal periods.

13. The shift register of claim 12, wherein the discharge unit outputs a second voltage to the output unit in response to the output signal of the next stage to discharge from the first voltage to the second voltage.

14. The shift register of claim 12, wherein the output unit outputs the second voltage as the output signal.

15. A shift register comprising a plurality of stages, wherein some stages of the plurality of stages are disposed on left side of a panel and the other stages of the plurality of stages are disposed on right side of the panel,

wherein each of the stages comprises:

a driving unit which charges to a predetermined voltage in response to one of an output start signal and an output signal of a previous stage, and which generates the output signal in response to any one of the clock signals; and

a discharge unit which discharges the predetermined voltage in response to an output signal of a next stage,

wherein the driving unit comprises;

an input unit which outputs a first voltage in response to one of the output start signal and an output signal of the previous stage; and

an output unit which charges to the first voltage and generates the output signal in response to any one of the clock signals,

wherein some stages disposed on left side of the panel and the other stages disposed on right side of the panel are alternatively connected to gate lines,

wherein each of the clock signals having a duty ratio of less than 50% and a different phase from each of the other clock signals,

wherein the output signal of the output unit is transmitted to a gate line and the next stage, and

wherein the clock signals for some stages disposed on left side of the panel or the other stages disposed on right side of the panel have high value with a frequency of every 4 horizontal periods.

16. The shift register of claim 15, wherein some stages disposed on left side of the panel and the other stages disposed on right side of the panel are alternatively connected to gate lines.

17. A shift register comprising a plurality of stages, wherein stages of the plurality of stages are connected to each other and a current (N-th) stage thereof generates an output signal in response to any one of a plurality of clock signals and an output from each of two different stages thereof, each of the clock signals having a duty ratio of less than 50% and a different phase from each of the other clock signals,

wherein each of the stages comprises:

a driving unit which charges to a predetermined voltage in response to one of an output start signal and an output signal of a previous stage, the previous stage being disposed two stages previous (N−

2) to the current stage, and which generates the output signal in response to any one of the clock signals; and

a discharge unit which discharges the predetermined voltage in response to an output signal of a next stage, the next stage being disposed two stages after (N+2) the current stage,

wherein the driving unit comprises;

an input unit which outputs a first voltage in response to one of the output start signal and an output signal of the previous (N−

2) stage; and

an output unit which charges to the first voltage and generates the output signal in response to any one of the clock signals,

wherein the output unit comprises two output circuits having substantially a same structure, and

wherein each of the stages further comprises an output assistant unit transmitting the first voltage to the output unit in response to an output of the input unit.

18. The shift register of claim 17, wherein the discharge unit outputs a second voltage to the output unit in response to the output signal of the next (N+2) stage to discharge from the first voltage to the second voltage.

19. The shift register of claim 18, wherein the output unit outputs the second voltage as the output signal.

20. The shift register of claim 17, wherein each stage has a set terminal, a reset terminal, a first output terminal and a second output terminal, and

the input unit comprises a first switching element connected between the first voltage and a first point of contact and having a control terminal connected to the set terminal, and

the output assistant unit comprises:

a second switching element connected between the first voltage and a second point of contact; and

a third and a fourth switching elements connected in series between the first voltage and the second voltage,

wherein a control terminal of the second switching element is connected to a point of contact between the third and the fourth switching elements, and the discharge unit comprises;

a fifth and a sixth switching elements connected in parallel between the first point of contact and the second voltage; and

a seventh and a eighth switching elements connected in parallel between the second point of contact and the second voltage,

wherein a control terminal of the fifth switching element is connected to the reset terminal, and a control terminal of the sixth switching element is connected to the second point of contact, and a control terminal of the seventh switching element is connected to the first point of contact, and a control terminal of the eighth switching element is connected to the set terminal, and

the output unit comprises;

a ninth switching element, a tenth switching element, an eleventh switching element and a twelfth switching element, the ninth and tenth switching elements being connected in series between the clock terminal and the second voltage, and the eleventh and twelfth switching elements being connected in series between the clock terminal and the second voltage; and

a first capacitor and a second capacitor connected between the first point of contact and the first and second output terminals, respectively,

wherein control terminals of the ninth and the eleventh switching elements are connected to the first point of contact and control terminals of the tenth and the eleventh switching elements are connected to the second point of contact,

wherein the first output terminal is connected to a point of contact between the ninth and tenth switching elements, and the second output terminal is connected to a point of contact between the eleventh and twelfth switching elements.

21. The shift register of claim 20, wherein the first to twelfth switching elements comprise amorphous silicon.