Light-emitting device and electronic device using the same

• US 20070008257A1
• Filed: 12/13/2005
• Published: 01/11/2007
• Est. Priority Date: 12/16/2004
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Seo, Satoshi, Kimura, Hajime, Yamazaki, Shunpei
• Granted Patent: US 8,803,853 B2
• Time in Patent Office: Days
• US Class Current: 345/83
• CPC Class Codes: G09G 2330/028 Generation of voltages supplied to electrode drivers in a matrix display other than LCD
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/2074 using sub-pixels
• CPC Class Codes: G09G 3/2077 by a combination of two or more gradation control methods
• 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
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/125 specially adapted for multicolour light emission, e.g. for emitting white light
• CPC Class Codes: H10K 59/351 comprising more than three subpixels, e.g. red-green-blue-white [RGBW]
• CPC Class Codes: H10K 59/353 characterised by the geometrical arrangement of the RGB subpixels

Abstract

It is an object to provide a light-emitting device and an electronic device which can provide an image with excellent image quality. One of the present inventions is a light-emitting device including a plurality of light-emitting elements each exhibiting a different emission color. At least one of the plurality of light-emitting elements has n light-emitting layers (n is a natural number, n≧2) between a pair of electrodes. Further, at least one of the n light-emitting layers includes a substance which provides emission from a triplet excitation state. In a light-emitting device having such a structure, an image is displayed by combining emissions from the plurality of light-emitting elements.

Claims

1. A light-emitting device characterized by comprising:

a plurality of light-emitting elements each exhibiting a different emission color,

wherein at least one of the light-emitting elements has n light-emitting layers (n≧

2, n is a natural number) between a pair of electrodes, and

wherein an image is displayed by combining emissions from the light-emitting elements.

2. The light-emitting device according to claim 1, characterized in that light-emitting substances included in the n light-emitting layers each exhibit different emission colors.

3. The light-emitting device according to claim 1, characterized in that the light emitting device has a plurality of power source potentials,

wherein respective different power source potentials are applied to the light-emitting elements each exhibiting a different emission color, and

wherein the plurality of power source potentials are generated by a voltage step-up circuit.

4. The light-emitting device according to claim 3, characterized in that the voltage set-up circuit is a charge pump.

5. The light-emitting device according to claim 4, characterized in that the charge pump comprises:

a constant voltage source;

a first rectifying element to an N-th rectifying element (N≧

2, N is a natural number); and

a first capacitor element to an N-th capacitor element,

wherein the first rectifying element to the N-th rectifying element are connected in series,

wherein an input terminal of the first rectifying element is connected to the constant voltage source,

wherein one electrode of each of the first capacitor element to the N-th capacitor element is connected to an output terminal of each of the first rectifying element to the N-th rectifying element,

wherein a clock pulse or a clock inverted pulse is inputted alternately to the other electrode of each of the first capacitor element to the (N−

1)-th capacitor element,

wherein a predetermined potential is inputted to the other electrode of the N-th capacitor element, and

wherein a power source potential obtained from an arbitrary one electrode of each of the first capacitor element to the N-th capacitor element, is applied to each of the light-emitting elements each exhibiting a different emission color.

6. A light-emitting device characterized by comprising:

a plurality of light-emitting elements each exhibiting a different emission color;

wherein at least one of the light-emitting elements has n light-emitting layers (n≧

2, n is a natural number) between a pair of electrodes,

wherein at least one of the light-emitting layers includes a substance exhibiting emission from a triplet excited state, and

wherein an image is displayed by combining emissions from the light-emitting elements.

7. The light-emitting device according to claim 6, characterized in that light-emitting substances included in the n light-emitting layers each exhibit different emission colors.

8. The light-emitting device according to claim 6, characterized in that the light emitting device has plurality of power source potentials,

wherein respective different power source potentials are applied to the light-emitting elements each exhibiting a different emission color, and

wherein the plurality of power source potentials are generated by a voltage step-up circuit.

9. The light-emitting device according to claim 8, characterized in that the voltage set-up circuit is a charge pump.

10. The light-emitting device according to claim 9, characterized in that the charge pump comprises:

a constant voltage source;

a first rectifying element to an N-th rectifying element (N≧

2, N is a natural number); and

a first capacitor element to an N-th capacitor element,

wherein the first rectifying element to the N-th rectifying element are connected in series,

wherein an input terminal of the first rectifying element is connected to the constant voltage source,

wherein one electrode of each of the first capacitor element to the N-th capacitor element is connected to an output terminal of each of the first rectifying element to the N-th rectifying element,

wherein a clock pulse or a clock inverted pulse is inputted alternately to the other electrode of each of the first capacitor element to the (N−

1)-th capacitor element,

wherein a predetermined potential is inputted to the other electrode of the N-th capacitor element, and

wherein a power source potential obtained from an arbitrary one electrode of each of the first capacitor element to the N-th capacitor element, is applied to each of the light-emitting elements each exhibiting a different emission color.

11. A light-emitting device characterized by comprising:

a plurality of light-emitting elements each exhibiting a different emission color;

wherein at least one of the light-emitting elements has n light-emitting layers (n≧

2, n is a natural number) between a pair of electrodes,

wherein between a m-th light-emitting layer (m is a natural number) and a (m+1)-th light-emitting layer, a layer which has a larger ionization potential than an ionization potential of the m-th light-emitting layer and which has a smaller electron affinity than an electron affinity of the (m+1)-th light-emitting layer is provided, and

wherein an image is displayed by combining emissions from the light-emitting elements.

12. The light-emitting device according to claim 11, characterized in that light-emitting substances included in the n light-emitting layers each exhibit different emission colors.

13. The light-emitting device according to claim 11, characterized in that the light emitting device has a plurality of power source potentials,

wherein different power source potential are applied to the light-emitting elements each exhibiting a different emission color, and

the plurality of power source potentials are generated by a voltage step-up circuit.

14. The light-emitting device according to claim 13, characterized in that the voltage step-up circuit is a charge pump.

15. The light-emitting device according to claim 14, the charge pump characterized by comprises:

a constant voltage source;

a first rectifying element to an N-th rectifying element (N≧

2, N is a natural number); and

a first capacitor element to an N-th capacitor element,

wherein the first rectifying element to the N-th rectifying element are connected in series,

wherein an input terminal of the first rectifying element is connected to the constant voltage source,

wherein one electrode of each of the first capacitor element to the N-th capacitor element is connected to an output terminal of each of the first rectifying element to the N-th rectifying element,

wherein a clock pulse or a clock inverted pulse is inputted alternately to the other electrode of each of the first capacitor element to the (N−

1)-th capacitor element,

wherein a predetermined potential is inputted to the other electrode of the N-th capacitor element, and

wherein a power source potential obtained from an arbitrary one electrode of each of the first capacitor element to the N-th capacitor element, is applied to each of the light-emitting elements each exhibiting a different emission color.

16. A light-emitting device characterized by comprising:

a plurality of light-emitting elements each exhibiting a different emission color;

wherein at least one of the light-emitting elements has n light-emitting layers (n≧

2, n is a natural number) between a pair of electrodes,

wherein at least one of the light-emitting layers includes a substance exhibiting emission from a triplet excited state,

wherein between a m-th light-emitting layer (m is a natural number) and a (m+1)-th light-emitting layer, a layer which has a larger ionization potential than an ionization potential of the m-th light-emitting layer and which has a smaller electron affinity than an electron affinity of the (m+1)-th light-emitting layer is provided, and

wherein an image is displayed by combining emissions from the light-emitting elements.

17. The light-emitting device according to claim 16, characterized in that light-emitting substances included in the n light-emitting layers each exhibit different emission colors.

18. The light-emitting device according to claim 16, characterized in that the light emitting device has a plurality of power source potentials,

wherein respective different power source potentials are applied to the light-emitting elements each exhibiting a different emission color, and

the plurality of power source potentials are generated by a voltage step-up circuit.

19. The light-emitting device according to claim 18, characterized in that the voltage set-up circuit is a charge pump.

20. The light-emitting device according to claim 19, characterized in that the charge pump comprises:

a constant voltage source;

a first rectifying element to an N-th rectifying element (N≧

2, N is a natural number); and

a first capacitor element to an N-th capacitor element,

wherein the first rectifying element to the N-th rectifying element are connected in series,

wherein an input terminal of the first rectifying element is connected to the constant voltage source,

wherein one electrode of each of the first capacitor element to the N-th capacitor element is connected to an output terminal of each of the first rectifying element to the N-th rectifying element,

wherein a clock pulse or a clock inverted pulse is inputted alternately to the other electrode of each of the first capacitor element to the (N−

1)-th capacitor element,

wherein a predetermined potential is inputted to the other electrode of the N-th capacitor element, and

wherein a power source potential obtained from an arbitrary one electrode of each of the first capacitor element to the N-th capacitor element, is applied to each of the light-emitting elements each exhibiting a different emission color.

21. A light-emitting device characterized by comprising:

a plurality of light-emitting elements each exhibiting a different emission color;

wherein at least one of the light-emitting elements has n light-emitting layers (n≧

2, n is a natural number) between a pair of electrodes,

wherein between a m-th light-emitting layer (m is a natural number) and a (m+1)-th light-emitting layer, a layer which includes an aromatic amine compound as well as a metal oxide including a metal belonging to Group 4 to 8 is provided, and

wherein an image is displayed by combining emissions from the light-emitting elements.

22. The light-emitting device according to claim 21, characterized in that light-emitting substances included in the n light-emitting layers each exhibit different emission colors.

23. The light-emitting device according to claim 21, characterized in that the light emitting device has a plurality of power source potentials,

wherein respective different power source potentials are applied to the light-emitting elements each exhibiting a different emission color, and

the plurality of power source potentials are generated by a voltage step-up circuit.

24. The light-emitting device according to claim 23, characterized in that the voltage set-up circuit is a charge pump.

25. The light-emitting device according to claim 24, characterized in that the charge pump comprises:

a constant voltage source;

a first rectifying element to an N-th rectifying element (N≧

2, N is a natural number); and

a first capacitor element to an N-th capacitor element,

wherein the first rectifying element to the N-th rectifying element are connected in series,

wherein an input terminal of the first rectifying element is connected to the constant voltage source,

wherein one electrode of each of the first capacitor element to the N-th capacitor element is connected to an output terminal of each of the first rectifying element to the N-th rectifying element,

wherein a clock pulse or a clock inverted pulse is inputted alternately to the other electrode of each of the first capacitor element to the (N−

1)-th capacitor element,

wherein a predetermined potential is inputted to the other electrode of the N-th capacitor element, and

wherein a power source potential obtained from an arbitrary one electrode of each of the first capacitor element to the N-th capacitor element, is applied to each of the light-emitting elements each exhibiting a different emission color.

26. A light-emitting device characterized by comprising:

a plurality of light-emitting elements each exhibiting a different emission color;

wherein at least one of the light-emitting elements has n light-emitting layers (n≧

2, n is a natural number) between a pair of electrodes,

wherein at least one of the light-emitting layers includes a substance exhibiting emission from a triplet excited state,

wherein between a m-th light-emitting layer (m is a natural number) and a (m+1)-th light-emitting layer, a layer which includes an aromatic amine compound as well as a metal oxide including a metal belonging to Group 4 to 8 is provided, and

wherein an image is displayed by combining emissions from the light-emitting elements.

27. The light-emitting device according to claim 26, characterized in that light-emitting substances included in the n light-emitting layers each exhibit different emission colors.

28. The light-emitting device according to claim 26, characterized in that the light emitting device has a plurality of power source potentials,

wherein different power source potential are applied to the light-emitting elements each exhibiting a different emission color, and

wherein the plurality of power source potentials are generated by a voltage step-up circuit.

29. The light-emitting device according to claim 28, characterized in that the voltage set-up circuit is a charge pump.

30. The light-emitting device according to claim 29, characterized in that the charge pump comprises:

a constant voltage source;

a first rectifying element to an N-th rectifying element (N≧

2, N is a natural number); and

a first capacitor element to an N-th capacitor element,

wherein the first rectifying element to the N-th rectifying element are connected in series,

wherein an input terminal of the first rectifying element is connected to the constant voltage source,

wherein one electrode of each of the first capacitor element to the N-th capacitor element is connected to an output terminal of each of the first rectifying element to the N-th rectifying element,

wherein a clock pulse or a clock inverted pulse is inputted alternately to the other electrode of each of the first capacitor element to the (N−

1)-th capacitor element,

wherein a predetermined potential is inputted to the other electrode of the N-th capacitor element, and

wherein a power source potential obtained from an arbitrary one electrode of each of the first capacitor element to the N-th capacitor element, is applied to each of the light-emitting elements each exhibiting a different emission color.

31. A light-emitting device characterized by comprising:

a first light-emitting element including a first light-emitting layer between a pair of electrodes;

a second light-emitting element including a second light-emitting layer between a pair of electrodes;

a third light-emitting element including a third light-emitting layer between a pair of electrodes; and

a fourth light-emitting element including the first light-emitting layer, the second light-emitting layer and the third light-emitting layer between a pair of electrodes,

wherein the fourth light-emitting element is adjacent to each of the first light-emitting element, the second light-emitting element and the third light-emitting element.

32. The light-emitting device according to claim 31, characterized in that one of the first light-emitting element, the second light-emitting element and the third light-emitting element exhibits reddish emission, another exhibits greenish emission and the other exhibits bluish emission.

33. A television image receiver characterized by comprising:

a module including a light-emitting device and a circuit board, which is incorporated in a casing,

wherein the light-emitting device includes a plurality of light-emitting elements each exhibiting a different emission color,

wherein at least one of the light-emitting elements has n light-emitting layers (n≧

2, n is a natural number) between a pair of electrodes, and

wherein an image is displayed by combining emissions from the light-emitting elements.

34. The television image receiver according to claim 33, characterized in that light-emitting substances included in the n light-emitting layers each exhibit different emission colors.

35. A television image receiver characterized by comprising:

a module including a light-emitting device and a circuit board, which is incorporated in a casing,

wherein the light-emitting device includes a plurality of light-emitting elements each exhibiting a different emission color,

wherein at least one of the light-emitting elements has n light-emitting layers (n≧

2, n is a natural number) between a pair of electrodes,

wherein at least one of the light-emitting layers includes a substance exhibiting emission from a triplet excited state, and

wherein an image is displayed by combining emissions from the light-emitting elements.

36. The television image receiver according to claim 35, characterized in that light-emitting substances included in the n light-emitting layers each exhibit different emission colors.

37. A television image receiver characterized by comprising:

a module including a light-emitting device and a circuit board, which is incorporated in a casing,

wherein the light-emitting device includes a plurality of light-emitting elements each exhibiting a different emission color,

wherein at least one of the light-emitting elements has n light-emitting layers (n≧

2, n is a natural number) between a pair of electrodes,

wherein between a m-th light-emitting layer (m is a natural number) and a (m+1)-th light-emitting layer, a layer which has a larger ionization potential than an ionization potential of the m-th light-emitting layer and which has a smaller electron affinity than an electron affinity of the (m+1)-th light-emitting layer is provided, and

wherein an image is displayed by combining emissions from the light-emitting elements.

38. The television image receiver according to claim 37, characterized in that light-emitting substances included in the n light-emitting layers each exhibit different emission colors.

39. A television image receiver characterized by comprising:

a module including a light-emitting device and a circuit board, which is incorporated in a casing,

wherein the light-emitting device includes a plurality of light-emitting elements each exhibiting a different emission color,

wherein at least one of the light-emitting elements has n light-emitting layers (n≧

2, n is a natural number) between a pair of electrodes,

wherein at least one of the light-emitting layers includes a substance exhibiting emission from a triplet excited state,

wherein between a m-th light-emitting layer (m is a natural number) and a (m+1)-th light-emitting layer, a layer which has a larger ionization potential than an ionization potential of the m-th light-emitting layer and which has a smaller electron affinity than an electron affinity of the (m+1)-th light-emitting layer is provided, and

wherein an image is displayed by combining emissions from the light-emitting elements.

40. The television image receiver according to claim 39, characterized in that light-emitting substances included in the n light-emitting layers each exhibit different emission colors.

41. A television image receiver characterized by comprising:

a module including a light-emitting device and a circuit board, which is incorporated in a casing,

wherein the light-emitting device includes a plurality of light-emitting elements each exhibiting a different emission color,

wherein at least one of the light-emitting elements has n light-emitting layers (n≧

2, n is a natural number) between a pair of electrodes,

wherein between a m-th light-emitting layer (m is a natural number) and a (m+1)-th light-emitting layer, a layer which includes an aromatic amine compound as well as a metal oxide including a metal belonging to Group 4 to 8 is provided, and

wherein an image is displayed by combining emissions from the light-emitting elements.

42. The television image receiver according to claim 41, characterized in that light-emitting substances included in the n light-emitting layers each exhibit different emission colors.

43. A television image receiver characterized by comprising:

a module including a light-emitting device and a circuit board, which is incorporated in a casing,

wherein the light-emitting device includes a plurality of light-emitting elements each exhibiting a different emission color,

wherein at least one of the light-emitting elements has n light-emitting layers (n≧

2, n is a natural number) between a pair of electrodes,

wherein at least one of the light-emitting layers includes a substance exhibiting emission from a triplet excited state,

wherein between a m-th light-emitting layer (m is a natural number) and a (m+1)-th light-emitting layer, a layer which includes an aromatic amine compound as well as a metal oxide including a metal belonging to Group 4 to 8 is provided, and

wherein an image is displayed by combining emissions from the light-emitting elements.

44. The television image receiver according to claim 43, characterized in that light-emitting substances included in the n light-emitting layers each exhibit different emission colors.

45. A television image receiver characterized by comprising:

a module including a light-emitting device and a circuit board, which is incorporated in a casing,

wherein the light-emitting device comprising a light-emitting element including a first light-emitting layer, a second light-emitting layer and a third light-emitting layer between a pair of electrodes,

wherein the first light-emitting layer includes a light-emitting substance exhibiting light of a color having a coordinate of CIE-XYZ color system in a region where x is 0.60 or more and y is 0.40 or less,

wherein the second light-emitting layer includes a light-emitting substance exhibiting light of a color having a coordinate of CIE-XYZ color system in a region where x is 0.30 or less and y is 0.60 or more, and

wherein the third light-emitting layer includes a light-emitting substance exhibiting light of a color having a coordinate of CIE-XYZ color system in a region where x is 0.20 or less and y is 0.20 or less.

46. A television image receiver characterized by comprising:

a module including a light-emitting device and a circuit board, which is incorporated in a casing,

wherein the light-emitting device comprising a light-emitting element including a first light-emitting layer and a second light-emitting layer between a pair of electrodes,

wherein the first light-emitting layer includes a light-emitting substance exhibiting light of a color having a coordinate of CIE-XYZ color system in a region where x is 0.40 or more but 0.55 or less, and y is 0.40 or more, and

wherein the second light-emitting layer includes a light-emitting substance exhibiting light of a color having a coordinate of CIE-XYZ color system in a region where x is 0.20 or less and y is 0.20 or less.

47. A television image receiver characterized by comprising:

a module including a light-emitting device and a circuit board, which is incorporated in a casing,

wherein the light-emitting device comprising a light-emitting element including a first light-emitting layer and a second light-emitting layer between a pair of electrodes,

wherein the first light-emitting layer includes a light-emitting substance exhibiting light of a color having a coordinate of CIE-XYZ color system in a region where x is 0.60 or more and y is 0.40 or less, and

wherein the second light-emitting layer includes a light-emitting substance exhibiting light of a color having a coordinate of CIE-XYZ color system in a region where x is 0.20 or less and y is 0.25 or more but 0.50 or less.