Organic electroluminescent display

• US 20080169754A1
• Filed: 04/26/2007
• Published: 07/17/2008
• Est. Priority Date: 01/15/2007
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Choi, Byoung Deog, Yang, Sun A.
• Granted Patent: US 8,773,406 B2
• Time in Patent Office: Days
• US Class Current: 313/504
• 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 2300/0852 being a dynamic memory with more than one capacitor
• CPC Class Codes: G09G 2300/0861 with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
• 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 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/045 Compensation of drifts in the characteristics of light emitting or modulating elements
• 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

An organic electroluminescent display that can prevent decreases in an average luminance of an organic electroluminescent element thereof includes: a data line to supply a data signal; a scan line to supply a scan signal; a first switching element having a control electrode electrically coupled to the scan line, to transfer the data signal from the data line; a first driving transistor having a control electrode electrically coupled to the first switching element, to control a driving current of a first voltage line; a first capacitive element having a first electrode electrically coupled to the first voltage line and having a second electrode electrically coupled to a control electrode of the first driving transistor; an organic electroluminescent element, electrically coupled to the first driving transistor and a third voltage line, to display an image in response to a current supplied from the first driving transistor; and a second voltage line to supply a reverse bias voltage of a second voltage line to the organic electroluminescent element.

Claims

1. An organic electroluminescent display comprising:

a data line to supply a data signal;

a scan line to supply a scan signal;

a first switching element including a control electrode, electrically coupled to the scan line, to transfer the data signal from the data line;

a first driving transistor including a control electrode, electrically coupled to the first switching element, to control a driving current of a first voltage line;

a first capacitive element including a first electrode electrically coupled to the first voltage line and a second electrode electrically coupled to a control electrode of the first driving transistor;

an organic electroluminescent element, electrically coupled to the first driving transistor and to a third voltage line, to display an image in response to being supplied with a current from the first driving transistor; and

a second voltage line to supply a reverse bias voltage from a second voltage line to the organic electroluminescent element.

2. The organic electroluminescent display of claim 1, further comprising a second switching element including a first electrode electrically coupled between the first driving transistor and the organic electroluminescent element, and a second electrode electrically coupled to the second voltage line.

3. The organic electroluminescent display of claim 1, wherein a voltage of the second voltage line is less than that of the third voltage line.

4. The organic electroluminescent display of claim 2, wherein the second switching element further comprises a control electrode electrically coupled to a prior scan line.

5. The organic electroluminescent display of claim 2, further comprising a third switching element electrically coupled between the first driving transistor and the organic electroluminescent element.

6. The organic electroluminescent display of claim 5, wherein the second and third switching elements each further comprise control electrodes electrically coupled to a light emitting control signal line.

7. The organic electroluminescent display of claim 5, wherein the third switching element is turned off in response to the first and second switching elements being turned on, and the third switching element being turned on in response to the first and second switching elements being turned off.

8. An organic electroluminescent display comprising:

a data line to supply a data signal;

a scan line to supply a scan signal;

a first switching element having a control electrode electrically coupled to the scan line, to transfer the data signal from the data line;

a first driving transistor to control a driving current of a first voltage line;

a second driving transistor having a control electrode electrically coupled to a control electrode of the first driving transistor, to compensate a threshold voltage and the data signal transferred by the first switching element;

a first capacitive element including a first electrode electrically coupled to the first voltage line and a second electrode electrically coupled to the control electrode of the first driving transistor;

an organic electroluminescent element, electrically coupled between the first driving transistor and a third voltage line, to display an image in response to being supplied with a current from the first driving transistor; and

a second switching element to supply a reverse bias voltage from a second voltage line to the organic electroluminescent element.

9. The organic electroluminescent display of claim 8, wherein the second switching element comprises a first electrode electrically coupled between the first driving transistor and the organic electroluminescent element and a second electrode electrically coupled to the second voltage line.

10. The organic electroluminescent display of claim 8, wherein a voltage of the second voltage line is less than that of the third voltage line.

11. The organic electroluminescent display of claim 8, wherein the second driving transistor has both a control electrode and a second electrode electrically coupled to the control electrode of the first driving transistor, the second driving transistor being electrically connected in a diode configuration.

12. The organic electroluminescent display of claim 8, further comprising a fourth switching element to initialize a voltage stored in the first capacitive element by supplying a voltage through the fourth voltage line.

13. The organic electroluminescent display of claim 12, wherein the fourth switching element is electrically coupled between the second driving transistor and the fourth voltage line.

14. The organic electroluminescent display of claim 11, wherein the second driving transistor is electrically coupled between the first switching element and the first driving transistor.

15. The organic electroluminescent display of claim 12, wherein the second and fourth switching elements each comprise control electrodes electrically coupled to a prior scan line.

16. The organic electroluminescent display of claim 8, further comprising a third switching element to transfer a driving current of the first driving transistor to the organic electroluminescent element.

17. The organic electroluminescent display of claim 16, wherein the second switching element comprises a first electrode electrically coupled between the third switching element and the organic electroluminescent element and a second electrode electrically coupled to the second voltage line.

18. The organic electroluminescent display of claim 16, wherein the third switching element is electrically coupled between the first driving transistor and the organic electroluminescent element.

19. The organic electroluminescent display of claim 16, wherein the third switching element comprises a control electrode electrically coupled to the prior scan line.

20. The organic electroluminescent display of claim 19, wherein the second and fourth switching elements each comprise control electrodes electrically coupled to the prior scan line.

21. The organic electroluminescent display of claim 20, wherein the third switching element is turned off in response to the first, second and fourth switching elements being turned on and the third switching element being turned on in response to the first, second and fourth switching elements being turned off.

22. The organic electroluminescent display of claim 16, wherein control electrode of the third switching element is electrically coupled to a light emitting control signal line.

23. The organic electroluminescent display of claim 16, further comprising a seventh switching element to transfer a driving current of the first driving transistor to the third switching element.

24. The organic electroluminescent display of claim 23, wherein the seventh switching element comprises a control electrode electrically coupled to the scan line.

25. An organic electroluminescent display comprising:

a data line to supply a data signal;

a scan line to supply a scan signal;

a first switching element having a control electrode electrically coupled to the scan line, to transfer the data signal from the data line;

a first driving transistor to control a driving current of a first voltage line;

a first capacitive element electrically coupled between the first switching element and the first voltage line;

a second capacitive element electrically coupled between the first capacitive element and the first driving transistor;

an organic electroluminescent element, electrically coupled between the first driving transistor and a third voltage line, to display an image in response to current supplied from the first driving transistor; and

a second switching element to supply a reverse bias voltage from a second voltage line to the organic electroluminescent element.

26. The organic electroluminescent display of claim 25, wherein the second switching element comprises a first electrode electrically coupled between the first driving transistor and the organic electroluminescent element and a second electrode electrically coupled to the second voltage line.

27. The organic electroluminescent display of claim 25, wherein a voltage of the second voltage line is less than that of the third voltage line.

28. The organic electroluminescent display of claim 25, further comprising a fifth switching element to electrically couple the first driving transistor into a diode configuration.

29. The organic electroluminescent display of claim 28, wherein the fifth switching element comprises a first electrode electrically coupled to a control electrode of the first driving transistor and a second electrode electrically coupled to the second electrode of the first driving transistor.

30. The organic electroluminescent display of claim 29, wherein the first driving transistor comprises a first electrode electrically coupled to the first voltage line and a second electrode electrically coupled to the second electrode of the fifth switching element.

31. The organic electroluminescent display of claim 29, further comprising a sixth switching element to supply a voltage from the first voltage line to the first capacitive element.

32. The organic electroluminescent display of claim 31, wherein the sixth switching element comprises a first electrode electrically coupled to the first voltage line and a second electrode electrically coupled between the first capacitive element and the second capacitive element.

33. The organic electroluminescent display of claim 31, further comprising a third switching element to transfer a driving current of the first diving transistor to the organic electroluminescent element.

34. The organic electroluminescent display of claim 33, wherein the third switching element is turned off in response to the first, second, fifth and sixth switching elements being turned on and the third switching element being turned on in response to the first, second, fifth and sixth switching elements being turned off.

35. The organic electroluminescent display of claim 32, wherein the second, fifth and sixth switching elements each comprise a control electrode electrically coupled to a prior scan line.

36. The organic electroluminescent display of claim 33, wherein the third switching element comprises a control electrode electrically coupled to the light emitting control line.

37. The organic electroluminescent display of claim 34, wherein the second, third, fifth and sixth switching elements each comprise control electrodes electrically coupled to a prior scan line.

38. The organic electroluminescent display of claim 34, wherein the second, fifth and sixth switching elements each comprise control electrodes electrically coupled to a prior scan line.

39. The organic electroluminescent display of claim 34, wherein the control electrode of the third switching element is electrically coupled to a light emitting signal control line.

40. An organic electroluminescent display comprising:

a data line to supply a data signal;

a scan line to supply a scan signal;

a first switching element having a control electrode electrically coupled to the scan line, to transfer the data signal from the data line;

a first driving transistor to control a driving current of a first voltage line;

a first capacitive element electrically coupled between a control electrode of the first driving transistor and the first voltage line;

a fifth switching element electrically coupling the first driving transistor into a diode configuration;

a organic electroluminescent element to display an image in response to current supplied from the first driving transistor; and

a second switching element to supply a reverse bias voltage from a second voltage line to the organic electroluminescent element.

41. The organic electroluminescent display of claim 40, wherein the second switching element comprises a first electrode electrically coupled to the organic electroluminescent element and a second electrode electrically coupled to the second voltage line.

42. The organic electroluminescent display of claim 40, wherein a voltage of the second voltage line is less than that of the third voltage line.

43. The organic electroluminescent display of claim 40, further comprising a sixth switching element electrically coupled between the first driving transistor and the first voltage line.

44. The organic electroluminescent display of claim 43, further comprising a third switching element to transfer a driving current from the first driving transistor to the organic electroluminescent element.

45. The organic electroluminescent display of claim 44, further comprising a fourth switching element to initialize a stored voltage of the first capacitive element by supplying a voltage of a fourth voltage line.

46. The organic electroluminescent display of claim 45, wherein the fifth switching element comprises a first electrode electrically coupled between the sixth switching element and the first driving transistor and a second electrode electrically coupled to a control electrode of the first driving transistor.

47. The organic electroluminescent display of claim 46, wherein the first switching element comprises a first electrode electrically coupled to the data line and a second electrode electrically coupled between the first driving transistor and the third switching element.

48. The organic electroluminescent display of claim 47, wherein the first, second and fifth switching elements each comprise control electrodes electrically coupled to the scan line.

49. The organic electroluminescent display of claim 47, wherein the sixth and third switching elements each comprise control electrodes electrically coupled to a light emitting control signal line.

50. The organic electroluminescent display of claim 47, wherein the fourth switching element comprises a control electrode electrically coupled to a prior scan line.

51. The organic electroluminescent display of claim 44, wherein the fourth switching element is electrically coupled to a prior scan line to initialize a stored voltage of the first capacitive element.

52. The organic electroluminescent display of claim 51, wherein the fifth switching element includes a first electrode electrically coupled between the third switching element and the first driving transistor and a second electrode electrically coupled to a control electrode of the first driving transistor.

53. The organic electroluminescent display of claim 52, wherein the first switching element comprises a first electrode electrically coupled the data line and a second electrode electrically coupled between the first driving transistor and the sixth switching element.

54. The organic electroluminescent display of claim 51, wherein the fourth switching element comprises a first electrode electrically coupled to the first capacitive element and a second electrode electrically coupled to a control electrode to result in a diode configuration.

55. The organic electroluminescent display of claim 53, wherein the first, second and fifth switching elements each comprise control electrodes electrically coupled to the scan line.

56. The organic electroluminescent display of claim 53, wherein the sixth and third switching elements each comprise control electrodes electrically coupled to a light emitting control line.

57. The organic electroluminescent display of claim 47, further comprising a third capacitive element having a first electrode electrically coupled between the scan line and a control electrode of the first switching element and a second electrode electrically coupled to the first driving transistor.

58. The organic electroluminescent display of claim 57, wherein the third capacitive element comprises a first electrode electrically coupled to the scan line and a second electrode electrically coupled to a control electrode of the first driving transistor.

59. The organic electroluminescent display of claim 57, wherein the control electrodes of the first, second and fifth switching elements are each coupled to the scan line.

60. The organic electroluminescent display of claim 57, wherein the sixth and third switching elements each comprise control electrodes electrically coupled to a light emitting control line.

61. The organic electroluminescent display of claim 57, wherein a control electrode of the fourth switching element is coupled to a prior scan line.

62. The organic electroluminescent display of claim 47, wherein a control electrode of the second switching element is coupled to a prior scan line.

63. The organic electroluminescent display of claim 53, wherein a control electrode of the second switching element is coupled to a prior scan line.

64. The organic electroluminescent display of claim 57, wherein a control electrode of the second switching element is coupled to a prior scan line.