Display device and driving method thereof

• US 20070030219A1
• Filed: 04/28/2006
• Published: 02/08/2007
• Est. Priority Date: 05/04/2005
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Sung, Si-Duk, Park, Kyong-Tae, Kim, Nam-Deog
• Application Number:
  US11/415,493
• Publication Number:
  US 20070030219A1
• Time in Patent Office: Days
• US Class Current: 345/76
• CPC Class Codes: G09G 2300/0465 Improved aperture ratio, e.g. by size reduction of the pixel circuit, e.g. for improving the pixel density or the maximum displayable luminance or brightness
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/0221 with use of split matrices G09G3/3644 and G09G3/3666 take precedence
• CPC Class Codes: G09G 2310/0254 Control of polarity reversal in general, other than for liquid crystal displays
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• 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

Abstract

A display device and a method of driving the display device include first and second pixel row groups having at least one pixel row including a plurality of pixels, a plurality of scan lines, a plurality of data lines, and a data driver generating the data voltage including a normal data voltage and a reverse bias voltage. The data driver applies one of the normal data voltage and the reverse bias voltage to the data line according to a selection signal. The normal data voltage is applied to the driving transistors of the first pixel row group, and the reverse bias voltage is applied to the driving transistors of the second pixel row group. Accordingly, the reverse bias voltages are applied to the pixels, preventing transition of threshold voltages of the driving transistors.

Claims

1. A display device comprising:

a first pixel row group and a second pixel row group, each group comprising at least one pixel row having a plurality of pixels, each pixel having a switching transistor, a capacitor, a driving transistor connected to the switching transistor, and a light emitting element connected to the driving transistor;

a plurality of scan signal lines connected to the switching transistors to transmit scan signals;

a plurality of data lines connected to the switching transistors to transmit data voltages, the data voltages comprising a normal data voltage and a reverse bias voltage; and

a data driver generating the data voltages, the data driver applying one of the normal data voltage and the reverse bias voltage to the data line according to a selection signal,

wherein the normal data voltage is applied to the driving transistors of the first pixel row group, and the reverse bias voltage is applied to the driving transistors of the second pixel row group.

2. The display device of claim 1,

wherein each of the first pixel row group and the second pixel row group comprises a plurality of pixel rows, and

wherein the normal data voltage is sequentially applied to the driving transistors of the first pixel row groups row-by-row, and

wherein the reverse bias voltage is simultaneously applied to the driving transistors of a plurality of the pixel rows of the second pixel row group.

3. The display device of claim 2,

wherein one frame is divided into a first interval and a second interval,

wherein, when the normal data voltage is applied to the driving transistors of the first pixel row group in the first interval, the reverse bias voltage is applied in the second interval, and

wherein, when the reverse bias voltage is applied to the driving transistors of the second pixel row group in the first interval, the normal data voltage is applied in the second interval.

4. The display device of claim 1,

wherein, after the normal data voltage is applied to the driving transistors of the first pixel row group, the reverse bias voltage is applied, and

wherein, after the reverse bias voltage is applied to the driving transistors of the second pixel row group, the normal data voltage is applied.

5. The display device of claim 4, wherein the first pixel row group and the second pixel row group are alternately arrayed.

6. The display device of claim 4, wherein the normal data voltage and the reverse bias voltage are alternately applied to the driving transistors row-by-row.

7. The display device of claim 4, further comprising a third pixel row group and a fourth pixel row group, each group comprising at least one pixel row,

wherein the normal data voltage is applied to the driving transistors of the third pixel row group, and the reverse bias voltage is applied to the driving transistors of the fourth pixel row group.

8. The display device of claim 7, wherein the first pixel row group, the second pixel row group, the third pixel row group and the fourth pixel row group are sequentially arrayed.

9. The display device of claim 8, wherein the reverse bias voltage is simultaneously applied to the second pixel row group and the fourth pixel row group.

10. The display device of claim 9, wherein the normal data voltage is sequentially applied to the driving transistors of the first pixel row group and the third pixel row group.

11. The display device of claim 1,

wherein the normal data voltage is sequentially applied to the driving transistors of a plurality of the pixel rows, and

wherein the reverse bias voltage is simultaneously applied to the driving transistors of a plurality of the pixel rows.

12. The display device of claim 11,

wherein one frame is divided into a first interval and a second interval,

wherein, when the normal data voltage is applied to the driving transistors in the first interval, the reverse bias voltage is applied in the second interval, and

wherein, when the reverse bias voltage is applied to the driving transistors in the first interval, the normal data voltage is applied in the second interval.

13. The display device of claim 1,

wherein the selection signal has a high level and a low level, and

wherein the data driver outputs one of the normal data voltage and the reverse bias voltage according to the level of the selection signal.

14. The display device of claim 13, wherein a period of the selection signal is a multiple of one horizontal period.

15. The display device of claim 14, wherein in one frame, a length of the interval where the data driver outputs the normal data voltage is equal to or larger than a length of the interval where the data driver outputs the reverse bias voltage.

16. The display device of claim 14, wherein in one period of the selection signal, a length of the level of the selection signal where the data driver outputs the normal data voltage is equal to or larger than a length of the level of the selection signal where the data driver outputs the reverse bias voltage.

17. The display device of claim 1, wherein a polarity of the reverse bias voltage is opposite to a polarity of the normal data voltage.

18. The display device of claim 17, wherein the reverse bias voltage is a negative voltage.

19. The display device of claim 18, wherein a size of the reverse bias voltage is proportional to a size of the normal data voltage.

20. The display device of claim 18, wherein the reverse bias voltage has a predetermined value.

21. A display device comprising:

a display panel that is divided into a plurality of blocks;

a plurality of scan signal lines disposed on the display panel to transmit scan signals;

a plurality of data lines intersecting the scan signal lines to transmit data voltages, the data voltages comprising a normal data voltage and a reverse bias voltage;

a plurality of pixels, each pixel having a switching transistor connected to the scan signal line and the data line, a capacitor, a driving transistor connected to the switching transistor, and a light emitting element connected to the driving transistor; and

a data driver generating the data voltage, the data driver applying one of the normal data voltage and the reverse bias voltage to the data line according to a selection signal,

wherein, when the reverse bias voltage is applied to the data line, the scan signals are simultaneously applied to at least two scan signal lines.

22. The display device of claim 21,

wherein one frame comprises a first interval and a second interval,

wherein, when the normal data voltage is applied to pixels in the first interval, the reverse bias voltage is applied in the second interval, and

wherein, when the reverse bias voltage is applied to the pixels in the first interval, the normal data voltage is applied in the second interval.

23. The display device of claim 22, further comprising a scan driver that applies scan signals to the scan signal lines to turn on the switching transistor of each pixel at least twice in one frame.

24. The display device of claim 21,

wherein the plurality of blocks comprise a first block and a second block,

wherein the scan signals are sequentially applied to the scan signal lines of the first block, and

wherein the scan signals are simultaneously applied to at least two scan signal lines of the second block.

25. The display device of claim 24,

wherein the normal data voltages are applied to the driving transistors of the first block, and

wherein the reverse bias voltages are applied to the driving transistors of the second block.

26. The display device of claim 21,

wherein the plurality of blocks comprise a first block, a second block, a third block and a fourth block that are sequentially arrayed,

wherein the scan signals are sequentially applied to the scan signal lines of the first block and the third block, and

wherein the scan signals are simultaneously applied to at least one scan signal line of the second block and at least one scan signal line of the fourth block.

27. The display device of claim 26,

wherein the normal data voltages are applied to the driving transistors of the first block and the third block, and

wherein the reverse bias voltages are applied to the driving transistors of the second block and the fourth block.

28. A method of driving a display device having a display panel that is divided into a plurality of blocks, a plurality of scan signal lines disposed on the display panel to transmit scan signals, a plurality of data lines transmitting data voltages comprising a normal data voltage and a reverse bias voltage, and a plurality of pixels, each pixel having a switching transistor connected to the scan signal line and the data line, a driving transistor connected to the switching transistor, and a light emitting element connected to the driving transistor, the method comprising:

applying the normal data voltage to the data lines;

applying the scan signals to the scan signal lines at the same time as or after applying the normal data voltage;

applying the reverse bias voltage to the data lines; and

simultaneously applying the scan signals to at least two of the scan signal lines at the same time as or after applying the reverse bias voltage.

29. The method of claim 28,

wherein the plurality of blocks comprise a first block and a second block,

wherein the applying the scan signals comprises applying the scan signals to the scan signal lines of the first block, and

wherein the simultaneously applying the scan signals comprises simultaneously applying the scan signals to at least two of the scan signal lines of the second block.

30. The method of claim 28,

wherein the plurality of blocks comprise a first block, a second block, a third block and a fourth block that are sequentially arrayed,

wherein applying the scan signals comprises sequentially applying the scan signals to the scan signal lines of the first block and the scan signal lines of the third block, and

wherein simultaneously applying the scan signals comprises simultaneously applying the scan signals to the scan signal lines of the second block and the scan signal lines of the fourth block.

31. The method of claim 28, further comprising:

dividing one frame into a first interval and a second interval;

applying the reverse bias voltages in the second interval when the normal data voltages are applied to the driving transistors in the first interval; and

applying the normal data voltages in the second interval when the reverse bias voltages are applied to the driving transistors in the first interval.