Dual panel-type organic electroluminescent device and method for fabricating the same

• US 7,132,801 B2
• Filed: 12/15/2004
• Issued: 11/07/2006
• Est. Priority Date: 12/15/2003
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Park, Jae-Yong, Kim, Sung-Ki, Kim, Hae-Yeol
• Primary Examiner(s): Philogene, Haissa
• Application Number:
  US11/011,778
• Publication Number:
  US 20050161740A1
• Time in Patent Office: 692 Days
• Field of Search: 315/169.3, 315/169.1, 313/498, 313/500, 313504-506, 345/204, 257/59, 257/72
• US Class Current: 315/169.3
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H01L 29/41733 for thin film transistors with insulated gate
• CPC Class Codes: H10K 59/1275 Electrical connections of the two substrates

Abstract

A dual panel-type active matrix organic electroluminescent device includes: first and second substrates spaced apart from each other; a driving thin film transistor on an inner surface of the first substrate; a connection electrode layer connected to the driving thin film transistor and formed of a first conductive material having a first hardness; a first electrode on an inner surface of the second substrate; an organic electroluminescent layer on the first electrode; and a second electrode on the organic electroluminescent layer, the second electrode connected to the connection electrode layer and formed of a second conductive material having a second hardness, wherein the first hardness is different from the second hardness.

Claims

1. A dual panel-type active matrix organic electroluminescent device, comprising:

first and second substrates spaced apart from each other;

a driving thin film transistor on an inner surface of the first substrate;

a connection electrode layer connected to the driving thin film transistor and formed of a first conductive material having a first hardness;

a first electrode on an inner surface of the second substrate;

an organic electroluminescent layer on the first electrode; and

a second electrode on the organic electroluminescent layer, the second electrode connected to the connection electrode layer and formed of a second conductive material having a second hardness,

wherein the first hardness is different from the second hardness.

2. The device of claim 1, wherein the first hardness is greater than the second hardness.

3. The device of claim 2, wherein a top portion of the connection electrode layer has an uneven surface.

4. The device of claim 2, wherein a top portion of the connection electrode layer has a saw-tooth shape.

5. The device of claim 1, further comprising a connection pattern between the connection electrode layer and the first substrate, wherein the connection pattern is formed of an insulating material and has a first height above the first substrate higher than a second height of the driving thin film transistor above the first substrate to make the connection electrode layer contact the second electrode.

6. The device of claim 1, wherein the driving thin film transistor includes a gate electrode, an active layer, an ohmic contact layer, a source electrode, and a drain electrode.

7. The device of claim 1, further comprising:

a gate line disposed along a first direction over the first substrate;

a data line disposed along a second direction so as to perpendicularly cross the gate line over the first substrate;

a power line disposed along the second direction over the first substrate and spaced apart from the data line; and

a switching thin film transistor disposed on the first substrate and connected to the gate line, the data line, and the driving thin film transistor.

8. The device of claim 1, wherein the organic electroluminescent layer includes red, green and blue emission layers.

9. The device of claim 8, further comprising a first carrier-transporting layer between the first electrode and each of the red, green and blue emission layers.

10. The device of claim 8, further comprising a second carrier-transporting layer between the second electrode and each of the red, green and blue emission layers.

11. The device of claim 1, further comprising a light shielding layer over the driving TFT, wherein the light shielding layer includes a first pattern of an organic material and a second pattern of an opaque conductive material.

12. A method of fabricating a dual panel-type active matrix organic electroluminescent device, comprising:

forming a driving thin film transistor on a first substrate;

forming a connection electrode layer over the first substrate using a first conductive material, the connection electrode layer contacting the driving thin film transistor and having a first hardness;

forming a first electrode on a second substrate;

forming an organic electroluminescent layer on the first electrode;

forming a second electrode on the organic electroluminescent layer using a second conductive material, the second electrode having a second hardness that is different from the first hardness; and

attaching the first substrate to the second substrate so as to connect the connection electrode layer to the second electrode.

13. The method of claim 12, wherein the first hardness is greater than the second hardness.

14. The method of claim 13, wherein a top portion of the connection electrode layer has an uneven surface.

15. The method of claim 13, wherein a top portion of the connection electrode layer has a saw-tooth shape.

16. The method of claim 12, further comprising forming a connection pattern between the connection electrode layer and the first substrate using an insulating material, wherein the connection pattern is formed to have a first height above the first substrate higher than second height of the driving thin film transistor above the first substrate to make the connection electrode layer contact the second electrode.

17. The method of claim 12, wherein the organic electroluminescent layer includes red, green and blue emission layers.

18. The method of claim 17, further comprising forming a first carrier-transporting layer between the first electrode and each of the red, green and blue emission layers.

19. The method of claim 17, further comprising forming a second carrier-transporting layer between the second electrode and each of the red, green and blue emission layers.

20. The method of claim 12, further comprising forming a light shielding layer over the driving thin film transistor, wherein the light shielding layer includes a first pattern of an organic material and a second pattern of an opaque conductive material.

21. A dual panel-type active matrix organic electroluminescent device, comprising:

first and second substrates spaced apart from each other;

an array layer on the first substrate, the array layer including a gate line, a data line, a power line, a switching thin film transistor connected to the gate and data lines, and a driving thin film transistor connected to the switching thin film transistor and the power line;

an electrical connector on the array layer, the electrical connector including a connection electrode layer connected to the driving thin film transistor;

light shielding layers on the array layer, the light shielding layers covering the switching and driving thin film transistors, respectively, and including an opaque conductive material; and

an organic electroluminescent diode on a rear surface of the second substrate, the organic electroluminescent diode connected to the electrical connector,

wherein the light shielding layers have a first height above the first substrate that is smaller than a second height of the electrical connector above the first substrate and made of a same material as the electrical connector.

22. The device of claim 21, further comprising a storage capacitor that includes a first capacitor electrode integrally connected to a switching drain of the switching thin film transistor and a second capacitor electrode integrally connected to the power line.

23. The device of claim 21, further comprising a thin film transistor connector that is connected to a switching drain of the switching thin film transistor through a first contact hole and integrally connected to a driving gate of the driving thin film transistor.

24. The device of claim 21, further comprising a power electrode extending from the power line over a driving source of the driving thin film transistor and contacting said driving source through a second contact hole.

25. The device of claim 21, wherein the electrical connector includes a connection pattern interposed between the array layer and the connection electrode layer, and wherein the connection pattern is formed of a photosensitive organic material.

26. The device of claim 25, wherein the connection electrode layer completely covers the connection pattern and contacts a driving drain of the driving thin film transistor through a third contact hole.

27. The device of claim 25, wherein the connection electrode layer is formed of an opaque conductive material.

28. The device of claim 21, wherein each of the light shielding layers includes a first pattern of a photosensitive organic material and a second pattern of said opaque conductive material.

29. The device of claim 21, wherein each of the switching and driving thin film transistors includes an active layer of undoped amorphous silicon and an ohmic contact layer of doped amorphous silicon.

30. The device of claim 21, further comprising a color filer layer including red, green and blue color filers, and a black matrix among said color filters, wherein the color filter layer and the black matrix are interposed between the second substrate and the organic electroluminescent diode.

31. The device of claim 30, further comprising a planarizing layer between the color filter layer and the organic electroluminescent diode.

32. The device of claim 31, further comprising a barrier layer between the planarizing layer and the organic electroluminescent diode.

33. The device of claim 21, wherein organic electroluminescent diode includes a first electrode, an organic electroluminescent layer and a second electrode in series.

34. The device of claim 33, wherein the first electrode is formed of a transparent conductive material.

35. The device of claim 33, wherein the connection electrode layer contacts both the second electrode of the organic electroluminescent diode and a driving drain of the driving thin film transistor.

36. The device of claim 33, further comprising an interlayer insulator on the first electrode, and a partition on the interlayer insulator, wherein the interlayer insulator corresponds to the gate, data and power lines, and wherein the partition has a tapered cross-sectional shape.

37. The device of claim 21, further comprising a sealant at peripheries of the first and second substrates so as to attach the first and second substrates together.

38. A method of fabricating a dual panel-type active matrix organic electroluminescent device, comprising:

forming an array layer on a first substrate, the array layer including a gate line, a data line, a power line, a switching thin film transistor connected to the gate and data lines, and a driving thin film transistor connected to the switching thin film transistor and the power line;

forming an electrical connector on the array layer, the electrical connector including a connection electrode layer connected to the driving thin film transistor;

forming light shielding layers on the array layer, the light shielding layers covering the switching and driving thin film transistors, respectively, and including an opaque conductive material;

forming an organic electroluminescent diode over a second substrate, the organic electroluminescent diode connected to the electrical connector; and

attaching the second substrate having the organic electroluminescent diode to the first substrate having the array layer using a sealant at peripheries of the first and second substrates.

39. The method of claim 38, wherein the light shielding layers have a first height above the first substrate smaller than a second height of the electrical connector above the first substrate and is formed of a same material as the electrical connector.

40. The method of claim 38, wherein the forming the array layer includes forming a storage capacitor that includes a first capacitor electrode integrally connected to a switching drain of the switching thin film transistor and a second capacitor electrode integrally connected to the power line.

41. The method of claim 38, wherein the forming the array layer includes forming a thin film transistor connector that is connected to a switching drain of the switching thin film transistor through a first contact hole and integrally connected to a driving gate of the driving thin film transistor.

42. The method of claim 38, wherein the forming the array layer includes forming a power electrode extending from the power line over a driving source of the driving thin film transistor and contacting said driving source through a second contact hole.

43. The method of claim 38, wherein the forming the electrical connector includes forming a connection pattern on the array layer using a photosensitive organic material and forming the connection electrode layer to completely cover the connection pattern.

44. The method of claim 43, wherein the connection electrode layer contacts a driving drain of the driving thin film transistor through a third contact hole.

45. The method of claim 43, wherein the connection pattern has a first height above the first substrate greater than a second height of the light shielding layers above the first substrate.

46. The method of claim 43, wherein the connection electrode layer is formed of an opaque conductive material.

47. The method of claim 38, wherein the forming each of the light shielding layers includes forming a first pattern of a photosensitive organic material on the array layer and forming a second pattern of said opaque conductive material on the first pattern.

48. The method of claim 38, wherein each of the switching and driving thin film transistors includes an active layer of undoped amorphous silicon and an ohmic contact layer of doped amorphous silicon.

49. The method of claim 38, further comprising forming a color filer layer including red, green and blue color filers on the second substrate, and forming a black matrix among said color filters.

50. The method of claim 49, further comprising forming a planarizing layer on the color filter layer and the black matrix.

51. The method of claim 50, further comprising forming a barrier layer on the planarizing layer, wherein the organic electroluminescent diode is disposed on the barrier layer.

52. The method of claim 51, wherein the forming the organic electroluminescent diode includes forming a first electrode over the barrier layer using a transparent conductive material, forming an organic electroluminescent layer on the first electrode, and forming a second electrode on the organic electroluminescent layer.

53. The method of claim 52, wherein the connection electrode layer contacts both the second electrode of the organic electroluminescent diode and a driving drain of the driving thin film transistor.

54. The method of claim 52, further comprising forming an interlayer insulator on the first electrode, and forming a partition on the interlayer insulator, wherein the interlayer insulator corresponds to the gate, data and power lines, and wherein the partition has a tapered cross-sectional shape such that a first portion close to the interlayer insulator is narrower than a second portion farther away from the interlayer insulator.

55. A method of fabricating a dual panel-type active matrix organic electroluminescent device, comprising:

patterning a first metal layer to form a driving gate and a gate line on a first substrate;

forming a first insulating layer on the first substrate to cover the patterned first metal layer;

forming a driving semiconductor layer on the first insulating layer over the driving gate, the driving semiconductor layer including an active layer of undoped amorphous silicon and an ohmic contact layer of doped amorphous silicon;

forming a driving source, a driving drain and a data line, wherein the driving source and drain are disposed on the ohmic contact layer, and the data line is disposed on the first insulating layer and perpendicularly crosses the gate line;

forming a driving channel within the active layer by etching a portion of the ohmic contact exposed between the driving source and drain to form a driving thin film transistor including the driving gate, the driving semiconductor layer, the driving source, and the driving drain;

forming a second insulating layer on the first insulating layer to cover the driving thin film transistor;

forming a power line and a power electrode on the second insulating layer, the power line spaced apart from the data line and perpendicularly crossing the gate line, the power electrode extending from the power line over the driving source to contact the driving source;

forming a third insulating layer on the second insulating layer to cover the power line and electrode;

patterning the third and second insulating layer to form a drain contact hole exposing a portion of the driving drain;

forming a photosensitive organic layer on the patterned second and third insulating layer;

forming a first pattern over the driving thin film transistor and a connection pattern next to the driving drain by exposing and developing the photosensitive organic layer using a mask, wherein the connection pattern has a first height above the first substrate greater than a second height of the first pattern above the first substrate;

forming a second pattern on the first pattern to form a light shielding layer and a connection electrode layer on the connection pattern to form an electrical connector by patterning an opaque conductive material, wherein the connection electrode layer completely covers the connection pattern and contacts the driving drain through the drain contact hole;

forming an organic electroluminescent diode over a second substrate; and

attaching the second substrate having the organic electroluminescent diode to the first substrate having the light shielding layer and the electrical connector so as to connect the connection electrode layer to the organic electroluminescent diode.

56. The method of claim 55, further comprising:

forming a color filter layer and a black matrix on the second substrate, the color filter layer including red, green and blue color filters, the black matrix disposed among the color filters;

forming a planarizing layer on the color filter layer and black matrix;

forming a barrier layer on the planarizing layer;

forming an interlayer insulator over the barrier layer in a position corresponding to the driving thin film transistor, the power line and the gate and data lines; and

forming a partition on the interlayer insulator, the partition having a tapered cross-sectional shape.

57. The method of claim 56, wherein forming the organic electroluminescent diode includes forming a first electrode on the barrier layer, forming an organic electroluminescent layer on the first electrode in an area defined by the partition, and forming a second electrode on the organic electroluminescent layer.

58. The method of claim 55, further comprising:

forming a switching gate and a thin film transistor connector;

forming a first contact hole exposing a portion of the thin film transistor connector;

forming a switching semiconductor layer on the first insulating layer over the switching gate, the switching semiconductor layer including an active layer of undoped amorphous silicon and an ohmic contact layer of doped amorphous silicon;

forming a switching source and drain on the ohmic contact layer of the switching semiconductor layer such that the switching drain contacts the thin film transistor connector through the first contact hole;

forming a switching channel between the switching source and drain to form a switching thin film transistor including the switching gate, the switching semiconductor layer, the switching source and the switching drain;

forming a second contact hole exposing a portion of the driving source so that the power electrode contacts the driving source through the second contact hole;

forming a first capacitor electrode integrally connected to the driving drain,

forming a second capacitor electrode extending from the power line to overlap the first capacitor electrode; and

forming another first pattern over the switching thin film transistor.

59. The method of claim 58, wherein the mask includes a plurality of slits in positions corresponding to the switching and driving thin film transistors.