Organic electroluminescent display device and method of manufacturing the same

• US 6,787,796 B2
• Filed: 10/09/2002
• Issued: 09/07/2004
• Est. Priority Date: 02/27/2002
• Status: Expired due to Term

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung SDI Company Limited
• Inventors: Do, Young-rag, Kim, Yoon-chang, Song, Young-woo, Park, Jin-woo
• Primary Examiner(s): JACKSON JR, JEROME
• Application Number:
  US10/266,702
• Publication Number:
  US 20030164496A1
• Time in Patent Office: 699 Days
• Field of Search: 257/40, 257/98, 438/29
• US Class Current: 257/40
• CPC Class Codes: H10K 50/85 Arrangements for extracting light from the devices
• CPC Class Codes: H10K 59/879 comprising refractive means, e.g. lenses

Abstract

An organic electroluminescent (EL) display device and a method of manufacturing the same. The organic EL device includes a substrate layer, a first electrode layer formed on the substrate layer, an organic layer formed on the first electrode layer, and a second electrode layer formed on the organic layer, wherein a light loss preventing layer having different refractive index areas is formed between layers of the organic EL device having a large difference in refractive index among the respective layers.

Claims

1. An organic electroluminescent (EL) display device comprising:

a substrate layer;

a first electrode layer formed on the substrate layer;

an organic layer formed on the first electrode layer;

a second electrode layer formed on the organic layer; and

a light loss preventing layer having areas with different refractive indices, formed between ones of the substrate, first electrode, organic, and second electrode layers having a large difference in refractive indices.

2. The organic EL device according to claim 1, wherein the light loss preventing layer is formed between the substrate layer and the first electrode layer.

3. The organic EL device according to claim 1, further comprising a planarization layer formed on the light loss preventing layer.

4. The organic EL device according to claim 1, wherein adjacent one of the areas having one refractive index has a pitch in the range of 50 to 3,000 nm.

5. The organic EL device according to claim 3, wherein the light loss preventing layer has a thickness in the range of 0.01 to 50 μ

m.

6. The organic EL device according to claim 2, wherein the first electrode is made of indium tin oxide (ITO).

7. The organic EL device according to claim 1, wherein the second electrode layer is made of ITO and the light loss preventing layer is formed thereon.

8. The organic EL device according to claim 1, wherein the light loss preventing layer comprises inorganic materials having different refractive indices and a difference in refractive indices is in the range of 0.3 to 3.0.

9. The organic EL device according to claim 8, wherein the inorganic materials comprises two or more materials selected from the group consisting of SiO_x(x>

1), SiN_x(x>

1), Si₃N₄, TiO₂, MgO, ZnO, Al₂O₃, SnO₂, In₂O₃, MgF₂, and CaF₂.

10. The organic EL device according to claim 8, wherein the light loss preventing layer has a light transmissivity of 80% or more.

11. The organic EL device according to claim 1, wherein the light loss preventing layer includes polymers having different refractive indices and a difference in refractive indices is 0.3 or more.

12. The organic EL device according to claim 11, wherein the light loss preventing layer is a composition comprising a photosensitive material and a binder resin.

13. The organic EL device according to claim 12, wherein the photosensitive material is one selected from silver halides.

14. The organic EL device according to claim 12, wherein the binder resin is made of gelatin.

15. The organic EL device according to claim 1, wherein the light loss preventing layer comprises areas of SiO_x(x>

1) and areas of TiO₂.

42. The organic EL device according to claim 2, wherein adjacent one of the areas having one refractive index has a pitch in the range of 50 to 3,000 nm.

43. The organic EL device according to claim 42, wherein the light loss preventing layer has a thickness in the range of 0.01 to 50 μ

m.

44. The organic EL device according to claim 9, wherein the light loss preventing layer has a light transmissivity of 80% or more.

45. The organic EL device according to claim 9, wherein the light loss preventing layer comprises areas of SiO_x(x>

1) and areas of TiO₂.

50. The organic EL device according to claim 4, wherein the light loss preventing layer has a thickness in the range of 0.01 to 50 μ

m.

16. An organic EL device comprising:

a transparent substrate;

a first electrode layer formed on the transparent substrate in a first predetermined pattern in a first direction, and made of a transparent conductive material;

an organic layer formed on the first electrode layer in a second predetermined pattern;

a second electrode layer formed on the organic layer in a second direction at a predetermined angle with respect to the first direction;

a light loss preventing layer provided between the substrate and the first electrode layer, wherein the light loss preventing layer has areas having different refractive indices, and is formed in a preset pattern; and

an encapsulation layer which encapsulates the first electrode layer, the organic layer and the second electrode layer.

17. The organic EL device according to claim 16, wherein adjacent one of the areas having one refractive index has a pitch in the range of 50 to 3,000 nm.

18. The organic EL device according to claim 16, wherein the light loss preventing layer has a thickness in the range of 0.01 to 50 μ

m.

19. The organic EL device according to claim 16, wherein the light loss preventing layer includes inorganic materials having different refractive indices and a difference in refractive indices is 0.3 or more.

20. The organic EL device according to claim 16, wherein the inorganic materials comprises two or more materials selected from the group consisting of SiO_x(x>

1), SiN_x;

(x>

1), Si₃N₄, TiO₂, MgO, ZnO, Al₂O₃, In₂O₃, SnO₂, MgF₂, and CaF₂.

21. The organic EL device according to claim 16, wherein the light loss preventing layer is a composition comprising a photosensitive material and a binder resin.

22. The organic EL device according to claim 21, wherein the photosensitive material is one selected from silver halides.

23. The organic EL device according to claim 21, wherein the binder resin is made of gelatin.

24. The organic EL device according to claim 20, wherein the light loss preventing layer comprises areas of SiO_x(x>

1) and areas of TiO₂.

25. The organic EL device according to claim 16, further comprising a planarization layer formed on the light loss preventing layer.

26. An organic EL device comprising:

a transparent substrate;

a pixel area having a transparent first electrode layer formed on the transparent substrate in a first predetermined pattern, an organic layer formed on the first electrode layer in a second predetermined pattern, an insulating layer formed over the transparent substrate which exposes a portion of the organic layer, and a second electrode layer formed on the organic layer and the insulating layer in a third predetermined pattern;

a drive area having thin film transistors (TFTs) formed on the transparent substrate, wherein the drive area selectively applies a predetermined voltage to the first electrode layer; and

a light loss preventing layer having areas having different refractive indices formed between the transparent substrate and the first electrode layer in a preset pattern.

27. The organic EL device according to claim 26, wherein adjacent one of the areas having one refractive index has a pitch in the range of 50 to 3,000 nm.

28. The organic EL device according to claim 27, wherein the light loss preventing layer has a thickness in the range of 0.01 to 50 μ

m.

29. The organic EL device according to claim 26, wherein the light loss preventing layer includes inorganic materials having different refractive indices and a difference in refractive indices is 0.3 or more.

30. The organic EL device according to claim 26, wherein the inorganic materials comprises two or more materials selected from the group consisting of SiO_x(x>

1), SiN_x(x>

1), Si₃N₄, TiO₂, MgO, ZnO, Al₂O₃, SnO₂, In₂O₃, MgF₂, and CaF₂.

31. The organic EL device according to claim 26, wherein the light loss preventing layer is a composition comprising a photosensitive material and a binder resin.

32. The organic EL device according to claim 26, further comprising a planarization layer formed on the light loss preventing layer.

33. An organic EL device having a thin film transistor (TFT), comprising:

a transparent substrate;

a buffer layer formed on the transparent substrate;

a thin film transistor (TFT) layer formed on the buffer layer;

an insulating layer which covers the TFT layer;

a first electrode layer formed on the insulating layer in a first predetermined pattern and to which voltages are selectively applied by the TFT;

an insulating planarization layer having an opening which exposes a portion of the first electrode layer;

an organic layer formed on the first electrode layer;

a second electrode layer formed on the organic layer and the planarization layer in a second predetermined pattern; and

a light loss preventing layer having areas having different refractive indices formed between the first electrode layer and the insulating layer, or on the second electrode layer in a preset pattern.

34. The organic EL device according to claim 33, wherein the light loss preventing layer includes two or more materials selected from the group consisting of SiO_x (x>

1), SiN_x(x>

1), Si₃N₄, TiO₂, MgO, ZnO, Al₂O₃, SnO₂, In₂O₃, MgF₂, and CaF₂.

35. The organic EL device according to claim 33, wherein the light loss preventing layer comprises areas of SiO_x(x>

1) and areas TiO₂.

46. The organic EL device according to claim 34, wherein the light loss preventing layer comprises areas of SiO_x(x>

1) and areas of TiO₂.

36. A method of manufacturing an organic EL device, the method comprising:

obtaining layers including a substrate layer, a first electrode layer formed on the substrate layer, an organic layer formed on the first electrode layer, and a second electrode layer formed on the organic layer; and

providing a light loss preventing layer having areas with different refractive indices between ones of the substrate, first electrode, organic, and second electrode layers having a large difference in refractive indices, wherein the providing of the light toss preventing layer comprises;

forming a first layer having a first component,

masking the first layer using a mask having a predetermined pattern,

injecting ions having a second component into the masked first layer, and

heat treating the ion-injected layer under an oxidative atmosphere to provide the light loss preventing layer having an ion injected area and a non-ion injected area having different corresponding refractive indices.

37. The method according to claim 36, wherein the first component and the second component include an inorganic material selected from the group consisting of SiO_x(x>

1), SiN_x(x>

1), Si₃N₄, TiO₂, MgO, ZnO, Al₂O₃, SnO₂, In₂O₃, MgF₂, and CaF₂.

38. The method according to claim 36, wherein the first component includes SiO_x(x>

1) and the second component includes TiO₂.

39. A method of manufacturing an organic EL device, the method comprising:

obtaining layers including a substrate layer, a first electrode layer formed on the substrate layer, an organic layer formed on the first electrode layer, and a second electrode layer formed on the organic layer; and

providing a light loss preventing layer having areas having different refractive indices, wherein the providing of the light loss preventing layer comprises;

forming a first layer by coating a composition including a photosensitive material and a binder resin,

exposing the coated first layer in a predetermined pattern, and

sequentially developing, bleaching and washing the exposed first layer.

40. The method according to claim 39, wherein the photosensitive material is one selected from silver halides.

41. The method according to claim 39, wherein the binder resin is made of gelatin.

47. An organic EL display device comprising:

layers which include a substrate layer, a first electrode layer, an organic layer which emits light, and a second electrode layer; and

a light loss preventing layer including areas having different refractive indices which selectively scatters and reflects the light, formed between ones of the layers, which include the substrate, first electrode, organic, and second electrode layers, having a large difference in refractive indices so as to prevent reflection at an interface of the layers.

48. The organic EL device according to claim 47, wherein ones areas of a first refractive index are alternately provided with areas of a second refractive index in the light loss preventing layer so as to increase an extraction efficiency of the light generated from the organic layer through the substrate layer.

49. The organic EL device according to claim 47, wherein the light loss preventing layer decreases loss and reflectivity of the light irradiated from the organic layer.