Light emitting device and method of manufacturing the same

• US 20040004434A1
• Filed: 06/20/2003
• Published: 01/08/2004
• Est. Priority Date: 07/05/2002
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Nishi, Takeshi, Nakamura, Yasuo
• Granted Patent: US 7,700,958 B2
• Time in Patent Office: Days
• US Class Current: 313/506
• CPC Class Codes: H01L 33/56 Materials, e.g. epoxy or silicone resin
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 2102/3031 Two-side emission, e.g. transparent OLEDs [TOLED]
• CPC Class Codes: H10K 50/82 Cathodes
• CPC Class Codes: H10K 50/84 Passivation; Containers; Encapsulations
• CPC Class Codes: H10K 50/8426 Peripheral sealing arrangements, e.g. adhesives, sealants
• CPC Class Codes: H10K 50/844 Encapsulations
• CPC Class Codes: H10K 59/00 Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/38 comprising colour filters or colour changing media [CCM]
• CPC Class Codes: H10K 59/8722 Peripheral sealing arrangements, e.g. adhesives, sealants
• CPC Class Codes: H10K 71/50 Forming devices by joining two substrates together, e.g. lamination techniques

Abstract

A light emitting device having a structure in which oxygen and moisture are prevented from reaching light emitting elements, and a method of manufacturing the same, are provided. Further, the light emitting elements are sealed by using a small number of process steps, without enclosing a drying agent. The present invention has a top surface emission structure. A substrate on which the light emitting elements are formed is bonded to a transparent sealing substrate. The structure is one in which a transparent second sealing material covers the entire surface of a pixel region when bonding the two substrates, and a first sealing material (having a higher viscosity than the second sealing material), which contains a gap material (filler, fine particles, or the like) for protecting a gap between the two substrates, surrounds the pixel region. The two substrates are sealed by the first sealing material and the second sealing material. Further, reaction between electrodes of the light emitting elements (cathodes or anodes) and the sealing materials can be prevented by covering the electrodes with a transparent protective layer, for example, CaF₂, MgF₂, or BaF₂.

Claims

1. A light emitting device comprising a pixel portion having a plurality of light emitting elements between a pair of substrates, at least one of the pair of substrates has transmittivity, the light emitting elements each comprising:

a first electrode;

a layer comprising an organic compound over the first electrode; and

a second electrode over the layer comprising the organic compound;

wherein;

the pair of substrates are fixed by a first sealing material disposed surrounding the pixel portion, and a second sealing material in contact with the first sealing material and covering the pixel portion; and

the first sealing material has openings in four comers.

2. A light emitting device according to claim 1, wherein the first sealing material has a linear shape and is disposed in the plane of the substrate, in parallel with one of an x-direction and a y-direction.

3. A light emitting device according to claim 1, wherein the second sealing material is exposed at the openings, and the circumference of the exposed second sealing material is curved.

4. A light emitting device according to claim 1, wherein the second sealing material is exposed at the openings, and the circumference of the exposed second sealing material protrudes from the openings.

5. A light emitting device according to claim 1, wherein the second sealing material is exposed at the openings, and the circumference of the exposed second sealing material is depressed inwardly from the opening portions.

8. A light emitting device according to claim 1, wherein the first sealing material contains a gap material that maintains a gap between the pair of substrates.

10. A light emitting device according to claim 1, wherein the second sealing material has higher transparency than the first sealing material.

12. A light emitting device according to claim 1, wherein the film thickness of the second electrode is from 1 nm to 10 nm.

14. A light emitting device according to claim 1, wherein there is provided a protective layer having transparency and made from CaF₂, MgF₂, or BaF₂, between the second electrode and the second sealing material.

16. A light emitting device according to claim 1, wherein light emitted from the light emitting elements is discharged through the second sealing material and one of the pair of substrates.

18. A light emitting device according to claim 1, wherein light emitted from the light emitting elements is discharged through the second sealing material and one of the pair of the substrates, and another one of the pair of substrates.

20. A light emitting element according to claim 1, wherein the light emitting device is any one of a video camera, a digital camera, a goggle-type display, a car navigation system, a personal computer, a DVD player, an electronic play equipment, and a portable information terminal.

6. A light emitting device comprising a pixel portion having a plurality of light emitting elements between a pair of substrates, at least one of the pair of substrates has transmittivity, the light emitting elements each comprising:

a first electrode;

a layer comprising an organic compound layer over the first electrode; and

a second electrode over the layer comprising the organic compound layer;

wherein;

a pair of first sealing materials sandwiching the pixel portion are disposed in an x-direction, and another pair of the first sealing materials sandwiching the pixel portion are disposed in a y-direction;

a second sealing material fills a space between at least one pair of the first sealing materials.

7. A light emitting device according to claim 6, wherein the shape of the first sealing material has bilateral symmetry and the first sealing material is disposed symmetrically sandwiching the pixel portion.

9. A light emitting device according to claim 6, wherein the first sealing material contains a gap material that maintains a gap between the pair of substrates.

11. A light emitting device according to claim 6, wherein the second sealing material has higher transparency than the first sealing material.

13. A light emitting device according to claim 6, wherein the film thickness of the second electrode is from 1 nm to 10 nm.

15. A light emitting device according to claim 6, wherein there is provided a protective layer having transparency and made from CaF₂, MgF₂, or BaF₂, between the second electrode and the second sealing material.

17. A light emitting device according to claim 6, wherein light emitted from the light emitting elements is discharged through the second sealing material and one of the pair of the substrates.

19. A light emitting device according to claim 6, wherein light emitted from the light emitting elements is discharged through the second sealing material and one of the pair of the substrates, and another one of the pair of substrates.

21. A light emitting element according to claim 6, wherein the light emitting device is any one of a video camera, a digital camera, a goggle-type display, a car navigation system, a personal computer, a DVD player, an electronic play equipment, and a portable information terminal.

22. A method of manufacturing a light emitting device comprising:

forming one pair of first sealing materials on a first substrate in an x-direction, and one pair of the first sealing materials in a y-direction, opening a gap between each pair of the first sealing materials, for a total of four of the first sealing materials;

dripping a second sealing material having transparency onto a region surrounded by the first sealing materials;

spreading out the second sealing material so that it fills at least a space between mutually opposing first sealing materials when bonding the first substrate and a second substrate, upon which a pixel portion provided with light emitting elements is formed, so that the pixel portion is disposed in a region surrounded by the first sealing materials; and

curing the first sealing materials and the second sealing material.

25. A method of manufacturing a light emitting device according to claim 22, wherein the step of curing the first sealing materials and the second sealing material is a step of irradiating ultraviolet light or a step of heat treatment.

28. A method of manufacturing a light emitting device according to claim 22, wherein the second sealing material has a low viscosity than the first sealing material.

31. A method of manufacturing a light emitting device according to claim 22, wherein there is a further step of sectioning the first substrate and the second substrate along the first sealing materials after curing the first sealing materials and the second sealing material.

23. A method of manufacturing a light emitting device comprising:

forming one pair of first sealing materials on a first substrate in an x-direction, and one pair of the first sealing materials in a y-direction, opening a gap between each pair of the first sealing materials, for a total of four of the first sealing materials;

dripping a second sealing material having transparency onto a region surrounded by the first sealing materials;

spreading out the second sealing material so that it protrudes out from between adjacent first sealing materials when bonding the first substrate and a second substrate, upon which a pixel portion provided with light emitting elements is formed, so that the pixel portion is disposed in a region surrounded by the first sealing materials; and

curing the first sealing materials and the second sealing material.

26. A method of manufacturing a light emitting device according to claim 23, wherein the step of curing the first sealing materials and the second sealing material is a step of irradiating ultraviolet light or a step of heat treatment.

29. A method of manufacturing a light emitting device according to claim 23, wherein the second sealing material has a low viscosity than the first sealing material.

32. A method of manufacturing a light emitting device according to claim 23, wherein there is a further step of sectioning the first substrate and the second substrate along the first sealing materials after curing the first sealing materials and the second sealing material.

24. A method of manufacturing a semiconductor device comprising:

forming one pair of first sealing materials on a first substrate, upon which a pixel portion provided with light emitting elements is formed, in an x-direction, and one pair of the first sealing materials in a y-direction, opening a gap between each pair of the first sealing materials, for a total of four of the first sealing materials so as to surround the pixel portion;

dripping a second sealing material having transparency onto the pixel portion;

spreading out the second sealing material so that it fills at least a space between mutually opposing first sealing materials when bonding the first substrate and the second substrate; and

curing the first sealing materials and the second sealing material.

27. A method of manufacturing a light emitting device according to claim 24, wherein the step of curing the first sealing materials and the second sealing material is a step of irradiating ultraviolet light or a step of heat treatment.

30. A method of manufacturing a light emitting device according to claim 24, wherein the second sealing material has a low viscosity than the first sealing material.

33. A method of manufacturing a light emitting device according to claim 24, wherein there is a further step of sectioning the first substrate and the second substrate along the first sealing materials after curing the first sealing materials and the second sealing material.

34. A light emitting device comprising a pixel portion having a plurality of light emitting elements between a pair of substrates, at least one of the pair of substrates has transmittivity, the light emitting elements each having comprising:

a first electrode;

a layer comprising an organic compound on and in contact with the first electrode; and

a second electrode on and in contact with the layer comprising the organic compound;

a protective layer having transparency on the second electrode and made from CaF₂, MgF₂, or BaF₂; and

a sealing material having transparency on the protective film;

wherein;

the first electrode is a laminate of metallic layers; and

the second electrode is made from a single layer of a metallic thin film having a film thickness of 1 nm to 10 nm.

35. A light emitting device according to claim 34, wherein the metallic thin film uses aluminum as its main constituent.

36. A light emitting device according to claims 34, wherein in the laminate of metallic layers, the layer that contacts the layer comprising the organic compound is a layer made from titanium nitride.

37. A light emitting device according to claim 34, wherein the first electrode contacts a source region or a drain region of a TFT.

38. A light emitting device according to claim 34, wherein the first electrode is electrically connected to a source region or a drain region of a TFT.

39. A light emitting device according to claim 34, wherein the metallic thin film is on and contacting a layer made from CaF₂, MgF₂, or BaF₂ that has a thinner film thickness than the metallic layer and there is a layer made from CaF₂, MgF₂, or BaF₂ on and contacting the metallic thin film, and having a thicker film thickness than the metallic layer.

40. A light emitting device according to claim 34, wherein the pair of substrates are fixed by a first sealing material disposed surrounding the pixel portion, and a second sealing materials that contacts the first sealing material and covers the pixel portion and the first sealing material has openings in its four corners.

41. A light emitting device comprising a pixel portion having a plurality of light emitting elements between a pair of substrates, at least one of the pair of substrates has transmittivity, the light emitting elements each comprising:

a first electrode;

a layer comprising an organic compound layer over the first electrode; and

a second electrode over the layer comprising the organic compound layer;

wherein;

a pair of first sealing materials sandwiching the pixel portion are aligned with a first edge of the pair of substrates, and another pair of the first sealing materials sandwiching the pixel portion are aligned with a second edge of the pair of substrates;

a second sealing material fills a space between at least one pair of the first sealing materials.

42. A light emitting device according to claim 41, wherein the shape of the first sealing material has bilateral symmetry and the first sealing material is disposed symmetrically sandwiching the pixel portion.

43. A light emitting device according to claim 41, wherein the first sealing material contains a gap material that maintains a gap between the pair of substrates.

44. A light emitting device according to claim 41, wherein the second sealing material has higher transparency than the first sealing material.

45. A light emitting device according to claim 41, wherein the film thickness of the second electrode is from 1 nm to 10 nm.

46. A light emitting device according to claim 41, wherein there is provided a protective layer having transparency and made from CaF₂, MgF₂, or BaF₂, between the second electrode and the second sealing material.

47. A light emitting device according to claim 41, wherein light emitted from the light emitting elements is discharged through the second sealing material and one of the pair of the substrates.

48. A light emitting device according to claim 41, wherein light emitted from the light emitting elements is discharged through the second sealing material and one of the pair of the substrates, and another one of the pair of substrates.

49. A light emitting element according to claim 41, wherein the light emitting device is any one of a video camera, a digital camera, a goggle-type display, a car navigation system, a personal computer, a DVD player, an electronic play equipment, and a portable information terminal.

50. A light emitting device according to claim 41, wherein the first edge of the pair of substrates and the second edge of the pair of substrates are perpendicular to each other.