DISPLAY DEVICE AND METHOD OF DRIVING THE SAME

• US 20070046590A1
• Filed: 08/17/2006
• Published: 03/01/2007
• Est. Priority Date: 08/26/2005
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: KIMURA, Hajime, UMEZAKI, Atsushi
• Granted Patent: US 7,986,287 B2
• Time in Patent Office: Days
• US Class Current: 345/76
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2320/029 by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/048 using evaluation of the usage time
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 3/3225 using an active matrix

Abstract

When a light-emitting element emits light for a long time, characteristics thereof change and current flowing therethrough is reduced even in the same voltage is applied. In particular, in a case of a display device with light-emitting element, there is a problem such that burn-in is generated in a display screen. A burn-in correction period in which characteristics of a light-emitting element in each pixel are detected is provided in addition to a normal driving period in which an image is displayed. The light-emitting element can emit light which compensates the changes in the characteristics, by correcting video signals inputted to each pixel in the normal driving period according to the characteristics of the light-emitting elements obtained in the burn-in correction period.

Claims

1. A display device comprising:

a battery;

a pixel including a light-emitting element;

a timer circuit;

a charging unit detection circuit; and

a driving method selection circuit,

wherein the timer circuit outputs a first signal for proceeding to a second burn-in correction period when a predetermined time passes after an end of a first burn-in correction period in which a characteristic of the light-emitting element are obtained through a first normal driving period in which an image is displayed,

wherein the charging unit detection circuit outputs a second signal for proceeding to the second burn-in correction period when the battery is charged, and

wherein the driving method selection circuit outputs a third signal for proceeding to the second burn-in correction period from the first normal driving period when the first signal and the second signal are inputted, and proceeding to a second normal driving period from the second burn-in correction period when the first signal and the second signal are not inputted.

9. The display device according to claim 1, wherein the characteristic of the light-emitting element included in the pixel is obtained by detecting current flowing to a counter electrode of the light-emitting element in the first burn-in correction period.

17. The display device according to claim 1, wherein the characteristic of the light-emitting element in the pixel is obtained by detecting current flowing in a power supply line of the light-emitting element in the first burn-in correction period.

25. The display device according to claim 1, wherein the characteristic of the light-emitting element in the pixel in a region in which deterioration of the characteristics is supposed to be easily generated is obtained preferentially in the first burn-in correction period.

33. The display device according to claim 9, wherein a potential of the counter electrode in the first burn-in correction period is same as that of the counter electrode in the first normal driving period.

41. The display device according to claim 17, wherein a potential of the power supply line in the first burn-in correction period is same as that of the power supply line in the first normal driving period.

49. The display device according to claim 1, wherein a driving frequency in the first burn-in correction period is same as that of the first normal driving period.

2. A displaying device comprising:

a pixel including a light-emitting element;

a timer circuit;

a non-operating detection circuit; and

a driving method selection circuit,

wherein the timer circuit outputs a first signal for proceeding to a second burn-in correction period when a predetermined time passes after an end of a first burn-in correction period in which a characteristic of the light-emitting element are obtained through a first normal driving period in which an image is displayed,

wherein the non-operating detection circuit outputs a second signal for proceeding to the second burn-in correction period when the display device is not turned on for a predetermined time, and

wherein the driving method selection circuit outputs a third signal for proceeding to the second burn-in correction period from the first normal driving period when the first signal and the second signal are inputted, and for proceeding to the second normal driving period from the second burn-in correction period when the first signal and the second signal are not inputted.

10. The display device according to claim 2, wherein the characteristic of the light-emitting element included in the pixel is obtained by detecting current flowing to a counter electrode of the light-emitting element in the first burn-in correction period.

18. The display device according to claim 2, wherein the characteristic of the light-emitting element in the pixel is obtained by detecting current flowing in a power supply line of the light-emitting element in the first burn-in correction period.

26. The display device according to claim 2, wherein the characteristic of the light-emitting element in the pixel in a region in which deterioration of the characteristics is supposed to be easily generated is obtained preferentially in the first burn-in correction period.

34. The display device according to claim 10, wherein a potential of the counter electrode in the first burn-in correction period is same as that of the counter electrode in the first normal driving period.

42. The display device according to claim 18, wherein a potential of the power supply line in the first burn-in correction period is same as that of the power supply line in the first normal driving period.

50. The display device according to claim 2, wherein a driving frequency in the first burn-in correction period is same as that of the first normal driving period.

3. A display device comprising:

a battery;

a pixel including a light-emitting element;

a timer circuit;

a charging unit detection circuit;

a surrounding luminance detection circuit; and

a driving method selection circuit,

wherein the timer circuit outputs a first signal for proceeding to a second burn-in correction period when a predetermined time passes after an end of a first burn-in correction period in which a characteristic of the light-emitting element are obtained through a first normal driving period in which an image is displayed,

wherein the charging unit detection circuit outputs a second signal for proceeding to the second burn-in correction period when the battery is charged,

wherein the surrounding luminance detection circuit outputs a third signal for proceeding to the second burn-in correction period when surrounding luminance around the display device is close to predetermined luminance, and

wherein the driving method selection circuit outputs a fourth signal for proceeding to the second burn-in correction period from the first normal driving period when the first signal, the second signal, and the third signal are inputted, and for proceeding to the second normal driving period from the second burn-in correction period when the first signal, the second signal, and the third signal are not inputted.

11. The display device according to claim 3, wherein the characteristic of the light-emitting element included in the pixel is obtained by detecting current flowing to a counter electrode of the light-emitting element in the first burn-in correction period.

19. The display device according to claim 3, wherein the characteristic of the light-emitting element in the pixel is obtained by detecting current flowing in a power supply line of the light-emitting element in the first burn-in correction period.

27. The display device according to claim 3, wherein the characteristic of the light-emitting element in the pixel in a region in which deterioration of the characteristics is supposed to be easily generated is obtained preferentially in the first burn-in correction period.

35. The display device according to claim 11, wherein a potential of the counter electrode in the first burn-in correction period is same as that of the counter electrode in the first normal driving period.

43. The display device according to claim 19, wherein a potential of the power supply line in the first burn-in correction period is same as that of the power supply line in the first normal driving period.

4. A display device comprising:

a pixel including a light-emitting element;

a timer circuit;

a non-operating detection circuit;

a surrounding luminance detection circuit; and

a driving method selection circuit,

wherein the timer circuit outputs a first signal for proceeding to a second burn-in correction period when a predetermined time passes after an end of a first burn-in correction period in which a characteristic of the light-emitting element are obtained through a first normal driving period in which an image is displayed,

wherein the non-operating detection circuit outputs a second signal for proceeding to the second burn-in correction period when the display device is not turned on for a predetermined time,

wherein the surrounding luminance detection circuit outputs a third signal for proceeding to the second burn-in correction period when surrounding luminance around a pixel portion of the display device is close to predetermined luminance, and

wherein the driving method selection circuit outputs a fourth signal for proceeding to the second burn-in correction period from the first normal driving period when the first signal, the second signal, and the third signal are inputted, and for proceeding to the second normal driving period from the second burn-in correction period when the first signal, the second signal, and the third signal are not inputted.

12. The display device according to claim 4, wherein the characteristic of the light-emitting element included in the pixel is obtained by detecting current flowing to a counter electrode of the light-emitting element in the first burn-in correction period.

20. The display device according to claim 4, wherein the characteristic of the light-emitting element in the pixel is obtained by detecting current flowing in a power supply line of the light-emitting element in the first burn-in correction period.

28. The display device according to claim 4, wherein the characteristic of the light-emitting element in the pixel in a region in which deterioration of the characteristics is supposed to be easily generated is obtained preferentially in the first burn-in correction period.

36. The display device according to claim 12, wherein a potential of the counter electrode in the burn-in correction period is same as that of the counter electrode in the normal driving period.

44. The display device according to claim 20, wherein a potential of the power supply line in the first burn-in correction period is same as that of the power supply line in the first normal driving period.

5. A display device comprising:

a pixel including a light-emitting element;

a timer circuit; and

a driving method selection circuit,

wherein the timer circuit outputs a first signal for proceeding to a second burn-in correction period when a predetermined time passes after an end of a first burn-in correction period in which a characteristic of the light-emitting element are obtained through a first normal driving period in which an image is displayed, and

wherein the driving method selection circuit outputs a second signal for proceeding to the burn-in correction period from the first normal driving period when the signal is inputted, and for proceeding to the second normal driving period from the burn-in correction period when the signal is not inputted.

13. The display device according to claim 5, wherein the characteristic of the light-emitting element included in the pixel is obtained by detecting current flowing to a counter electrode of the light-emitting element in the first burn-in correction period.

21. The display device according to claim 5, wherein the characteristic of the light-emitting element in the pixel is obtained by detecting current flowing in a power supply line of the light-emitting element in the first burn-in correction period.

29. The display device according to claim 5, wherein the characteristic of the light-emitting element in the pixel in a region in which deterioration of the characteristics is supposed to be easily generated is obtained preferentially in the first burn-in correction period.

37. The display device according to claim 13, wherein a potential of the counter electrode in the first burn-in correction period is same as that of the counter electrode in the first normal driving period.

45. The display device according to claim 21, wherein a potential of the power supply line in the first burn-in correction period is same as that of the power supply line in the first normal driving period.

6. A display device comprising:

a battery;

a pixel including a light-emitting element;

a start circuit;

a charging unit detection circuit; and

a driving method selection circuit,

wherein the start circuit can select either to proceed to a first normal driving period in which an image is displayed or to a burn-in correction period in which a characteristic of the light-emitting element is obtained, and outputs a first signal for proceeding to the burn-in correction period when proceeding to the burn-in correction period is selected,

wherein the charging unit detection circuit outputs a second signal for proceeding to the burn-in correction period when the battery is charged, and

wherein the driving method selection circuit outputs a third signal for proceeding to the burn-in correction period from the first normal driving period when the first signal and the second signal are inputted, and for proceeding to the second normal driving period from the burn-in correction period when the first signal and the second signal are not inputted.

14. The display device according to claim 6, wherein the characteristic of the light-emitting element included in the pixel is obtained by detecting current flowing to a counter electrode of the light-emitting element in the first burn-in correction period.

22. The display device according to claim 6, wherein the characteristic of the light-emitting element in the pixel is obtained by detecting current flowing in a power supply line of the light-emitting element in the first burn-in correction period.

30. The display device according to claim 6, wherein the characteristic of the light-emitting element in the pixel in a region in which deterioration of the characteristics is supposed to be easily generated is obtained preferentially in the first burn-in correction period.

38. The display device according to claim 14, wherein a potential of the counter electrode in the first burn-in correction period is same as that of the counter electrode in the first normal driving period.

46. The display device according to claim 22, wherein a potential of the power supply line in the first burn-in correction period is same as that of the power supply line in the first normal driving period.

7. A display device comprising:

a pixel including a light-emitting element;

a start circuit;

a surrounding luminance detection circuit; and

a driving method selection circuit,

wherein the start circuit can select either to proceed to a first normal driving period in which an image is displayed or to a burn-in correction period in which a characteristic of the light-emitting element is obtained, and outputs a first signal for proceeding to the burn-in correction period when proceeding to the burn-in correction period is selected,

wherein the surrounding luminance detection circuit outputs a second signal for proceeding to the burn-in correction period when surrounding luminance around a pixel portion of the display device is close to predetermined luminance, and

wherein the driving method selection circuit outputs a third signal for proceeding to the burn-in correction period from the first normal driving period when the first signal and the second signal are inputted, and for proceeding to the second normal driving period from the burn-in correction period when the first signal and the second signal are not inputted.

15. The display device according to claim 7, wherein the characteristic of the light-emitting element included in the pixel is obtained by detecting current flowing to a counter electrode of the light-emitting element in the first burn-in correction period.

23. The display device according to claim 7, wherein the characteristic of the light-emitting element in the pixel is obtained by detecting current flowing in a power supply line of the light-emitting element in the first burn-in correction period.

31. The display device according to claim 7, wherein the characteristic of the light-emitting element in the pixel in a region in which deterioration of the characteristics is supposed to be easily generated is obtained preferentially in the first burn-in correction period.

39. The display device according to claim 15, wherein a potential of the counter electrode in the first burn-in correction period is same as that of the counter electrode in the first normal driving period.

47. The display device according to claim 23, wherein a potential of the power supply line in the first burn-in correction period is same as that of the power supply line in the first normal driving period.

8. A display device comprising:

a battery;

a pixel including a light-emitting element;

a start circuit which can select either to proceed to a first normal driving period in which an image is displayed or to a burn-in correction period in which a characteristic of the light-emitting element is obtained, and which outputs a first signal for proceeding to the burn-in correction period when proceeding to the burn-in correction period is selected;

a charging unit detection circuit which outputs a second signal for proceeding to the burn-in correction period when the battery is charged;

a surrounding luminance detection circuit which outputs a third signal for proceeding to the burn-in correction period when surrounding luminance around a pixel portion of the display device is close to predetermined luminance; and

a driving method selection circuit which outputs a fourth signal for proceeding to the second burn-in correction period from the first normal driving period when the first signal, the second signal, and the third signal are inputted, and for proceeding to the second normal driving period from the second burn-in correction period when the first signal, the second signal, and the third signal are not inputted.

16. The display device according to claim 8, wherein the characteristic of the light-emitting element included in the pixel is obtained by detecting current flowing to a counter electrode of the light-emitting element in the first burn-in correction period.

24. The display device according to claim 8, wherein the characteristic of the light-emitting element in the pixel is obtained by detecting current flowing in a power supply line of the light-emitting element in the first burn-in correction period.

32. The display device according to claim 8, wherein the characteristic of the light-emitting element in the pixel in a region in which deterioration of the characteristics is supposed to be easily generated is obtained preferentially in the first burn-in correction period.

40. The display device according to claim 16, wherein a potential of the counter electrode in the first burn-in correction period is same as that of the counter electrode in the first normal driving period.

48. The display device according to claim 24, wherein a potential of the power supply line in the first burn-in correction period is same as that of the power supply line in the first normal driving period.

51. A method for driving a display device comprising the steps of:

obtaining a characteristic of a light-emitting element in a first burn-in correction period,

outputting a first signal for proceeding to a second burn-in correction period when a predetermined time passes through a first normal driving period in which an image is displayed,

outputting a second signal for proceeding to the second burn-in correction period when the battery is charged, and

outputting a third signal for proceeding to the second burn-in correction period from the first normal driving period when the first signal and the second signal are inputted, and for proceeding to the second normal driving period from the second burn-in correction period when the first or second signal is not inputted.

52. A method for driving a display device comprising the steps of:

obtaining a characteristic of a light-emitting element in a first burn-in correction period,

outputting a first signal for proceeding to a second burn-in correction period when a predetermined time passes through a first normal driving period in which an image is displayed, and

outputting a second signal for proceeding to the second burn-in correction period from the first normal driving period when the first signal is inputted, and for proceeding to the second normal driving period from the second burn-in correction period when the first signal is not inputted.

53. A method for driving a display device comprising the steps of:

obtaining a characteristic of a light-emitting element in a first burn-in correction period,

outputting a first signal for proceeding to a second burn-in correction period when a predetermined time passes through a first normal driving period in which an image is displayed,

outputting a second signal for proceeding to the second burn-in correction period when the display device is not turned on for a predetermined time, and

outputting a third signal for proceeding to the second burn-in correction period from the first normal driving period when the first signal and the second signal are inputted, and for proceeding to the second normal driving period from the second burn-in correction period when the first or second signal is not inputted.