Display device and driving method thereof

• US 20060007072A1
• Filed: 05/25/2005
• Published: 01/12/2006
• Est. Priority Date: 06/02/2004
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choi, Joon-Hoo, Park, Cheol-Woo, Kim, Nam-Deog, Choi, Beohm-Rock, Huh, Jong-Moo, Ko, Chun-Seok
• Application Number:
  US11/137,145
• Publication Number:
  US 20060007072A1
• Time in Patent Office: Days
• US Class Current: 345/76
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0866 by means of changes in the pixel supply voltage
• CPC Class Codes: G09G 2310/0218 with collection of electrodes in groups for n-dimensional addressing
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2310/0254 Control of polarity reversal in general, other than for liquid crystal displays
• CPC Class Codes: G09G 2310/0256 with the purpose of reversing the voltage across a light emitting or modulating element within a pixel
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3291 in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting elements

Abstract

A display device is provided, including light emitting elements, first switching transistors transmitting data signals in response to scanning signals, second switching transistors transmitting a reverse bias voltage in response to a switching signal, capacitors charging voltages based on the data signals and discharging based on the reverse bias voltage; and driving transistors, each driving a transistor connected to a driving voltage and turning on and off in response to the voltage charged in the capacitor to connect and disconnect a signal passage from the driving voltage to the light emitting element.

Claims

1. A display device comprising:

a plurality of light emitting elements;

a plurality of first switching transistors transmitting data signals in response to scanning signals;

a plurality of second switching transistors transmitting a reverse bias voltage in response to a switching signal;

a plurality of capacitors charging voltages based on the data signals and discharging based on the reverse bias voltage; and

a plurality of driving transistors, each driving transistor connected to a driving voltage and turning on and off in response to the voltage charged in the capacitor to connect and disconnect a signal passage from the driving voltage to the light emitting element.

2. The display device of claim 1, wherein the reverse bias voltage is lower than 0V.

3. The display device of claim 1, wherein the first switching transistors sequentially turn on during a first period and simultaneously turn off during second and third periods, and the second switching transistors turn off during the first and the second periods and turn on during the third period.

4. The display device of claim 3, wherein the driving voltage is higher than a common voltage connected to the light emitting elements during the second period and the light emitting elements simultaneously emit light during the second period.

5. The display device of claim 4, wherein the driving voltage has at least two different voltage levels.

6. The display device of claim 4, wherein the common voltage has at least two different voltage levels.

7. The display device of claim 4, wherein the second switching transistors simultaneously turn on after a predetermined time elapses from the light emission of the light emitting elements.

8. The display device of claim 1, wherein the pixels comprise a first pixel group and a second pixel group, a turn-on time of the first switching transistors of the second pixel group is different from a turn-on time of the first switching transistors of the first pixel group, and a turn-on time of the second switching transistors of the second pixel group is different from a turn-on time of the second switching transistors of the first pixel group.

9. The display device of claim 8, wherein the turn-on time of the first switching transistors of the second pixel group and the turn-on time of the first switching transistors of the first pixel group are successive.

10. The display device of claim 8, wherein the light emitting elements of the first pixel group and the light emitting elements of the second pixel group emit light at least in part at the same time.

11. The display device of claim 8, wherein the pixels further comprise a third pixel group, a turn-on time of the first switching transistors of the third pixel group is different from the turn-on times of the first switching transistors of the first and the second pixel groups, and a turn-on time of the second switching transistors of the third pixel group is different from the turn-on times of the second switching transistors of the first and the second pixel groups.

12. The display device of claim 8, further comprising first and second driving signal lines connected to the first and the second pixel groups, respectively, and transmitting the driving voltage, wherein the first driving signal lines are separated from the second signal lines.

13. The display device of claim 12, wherein each of the first and the second driving signal lines comprises at least one stem extending in a direction and a plurality of first branches branched from the at least one stem and extending substantially parallel to each other.

14. The display device of claim 13, wherein each of the first and the second driving signal lines further comprises a plurality of second branches intersecting the first branches.

15. The display device of claim 1, wherein the first and the second switching transistors and the driving transistors comprise amorphous silicon.

16. The display device of claim 1, wherein the first and the second switching transistors and the driving transistors comprise n-channel thin film transistors.

17. The display device of claim 1, further comprising:

a scanning driver generating the scanning signals;

a data driver generating the data signals; and

a driving voltage generator generating the driving voltage and the switching signal.

18. The display device of claim 17, further comprising a signal controller controlling the scanning driver, the data driver, and the driving voltage generator.

19. The display device of claim 17, wherein the data signals comprise voltage signals.

20. A method of driving a display device including first pixels, each of the first pixels including a first light emitting element and a first driving transistor supplying current to the first light emitting element, the method comprising:

sequentially writing first data signals to the first pixels;

simultaneously emitting light from the first light emitting elements based on the written data signals after the writing of the first data signals for all of the first pixels is finished; and

simultaneously supplying a reverse bias to the first driving transistors,

wherein the emission of light from the first light emitting elements is suppressed during the writing of the first data signals.

21. The method of claim 20, wherein the suppression of the light emission of the first light emitting elements comprises:

decreasing a magnitude of a voltage applied to the first light emitting elements through the first driving transistors.

22. The method of claim 20, wherein the display device further comprises second pixels, each of the second pixels including a second light emitting element and a second driving transistor supplying current to the second light emitting element, the method further comprising:

sequentially writing second data signals to the second pixels;

simultaneously emitting light from the second light emitting elements based on the written data signals after the writing of the second data signals for all of the second pixels is finished; and

simultaneously supplying a reverse bias to the second driving transistors,

wherein the emission of light from the second light emitting elements is suppressed during the writing of the second data signals, and the writing of the second data signals starts after the writing of the first data signals.

23. The method of claim 22, wherein the emission of light from the second light emitting elements overlaps the emission of light from the first light emitting elements, at least in part.

24. The method of claim 22, wherein a duration of the writing of the first data signals is substantially equal to a duration of the writing of the second data signals, and the writing of the second data signals starts immediately after the writing of the first data signals.

25. The method of claim 22, wherein the suppression of the light emission of the first and the second light emitting elements comprises:

decreasing a magnitude of a voltage applied to the first and the second light emitting elements through the first and the second driving transistors.