Enhancement of light extraction with cavity and surface modification

• US 7,504,770 B2
• Filed: 02/09/2005
• Issued: 03/17/2009
• Est. Priority Date: 02/09/2005
• Status: Active Grant

• Current Assignee: Pictiva Displays International Limited (f/k/a Dolya Holdco 5 Limited) (Key Patent Innovations Limited)
• Original Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Inventors: Choong, Vi-En
• Primary Examiner(s): Patel; Ashok
• Application Number:
  US11/054,997
• Publication Number:
  US 20060175961A1
• Time in Patent Office: 1,497 Days
• Field of Search: None
• US Class Current: 313/504
• CPC Class Codes: H10K 50/852 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 50/858 comprising refractive means, e.g. lenses
• CPC Class Codes: H10K 59/876 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 59/879 comprising refractive means, e.g. lenses

Abstract

An organic light emitting diode (OLED) device includes an anode layer upon a DBR (Distributed Bragg Reflector) stack such that the anode layer is modified by creating lens-like features on its surface. The OLED device also includes a planarizing layer on said anode layer, said planarizing layer filling in said lens-like features, said planarizing layer providing a flat uniform surface for the deposition of other layers thereupon.

Claims

1. An organic light emitting device, comprising:

a substrate;

a distributed Bragg reflector (DBR) stack on said substrate;

an anode layer on said DBR stack wherein said anode layer is modified by creating lens-like features, said lens-like features not adjacent to said DBR stack; and

a planarizing layer on said anode layer, said planarizing layer filling in said lens-like features, said planarizing layer providing a flat uniform surface for deposition of other layers thereupon.

2. The device according to claim 1 wherein said lens-like features are created by serrating a surface of said anode layer which is not adjacent to said DBR stack.

3. The device according to claim 1 further comprising:

a hole injection layer on said planarizing layer; and

an electro-luminescent layer on said hole injection layer, said electro-luminescent layer outputting light upon exciton formation therein.

4. The device according to claim 1 wherein said DBR stack comprises a plurality of substantially non-absorbing materials, said DBR stack capable of amplifying a luminance of at least some wavelengths of light emitted from said device.

5. The device according to claim 1 wherein said lens-like features are capable of amplifying a luminance of at least some wavelengths of light emitted from said device.

6. The device according to claim 1 wherein said planarizing layer is transparent.

7. The device according to claim 2 wherein a serrating pattern is random.

8. The device according to claim 1 wherein said lens-like features are created by patterning a surface of said anode layer which is not adjacent to said DBR stack.

9. The device according to claim 8 wherein patterning includes at least one of:

dry etching, wet etching, lithography, stamping or sputtering.

10. The device according to claim 5 wherein the height of the lens-like features is between 1% and 100% of any particular wavelength of light to be amplified.

23. The device according to claim 1 wherein said planarizing layer comprises a hole injection layer material.

11. A method of fabricating an organic light emitting diode device, said method comprising:

fabricating a distributed Bragg reflector (DBR) stack on a substrate;

fabricating an anode layer on said DBR stack wherein said anode layer is modified by creating lens-like features, said lens-like features not adjacent to said DBR stack; and

fabricating a planarizing layer on said anode layer, said planarizing layer filling in said lens-like features, said planarizing layer providing a flat uniform surface for deposition of other layers thereupon.

12. The method of claim 11 wherein creating lens-like features includes:

serrating a surface of said anode layer that is not adjacent to said DBR stack.

13. The method of claim 11 further comprising:

fabricating a hole injection layer on said planarizing layer; and

fabricating an electro-luminescent layer on said hole injection layer, said electro-luminescent layer outputting light upon exciton formation therein.

14. The method of claim 11 wherein said DBR stack comprises a plurality of substantially non-absorbing materials, said DBR stack capable of amplifying the luminance of at least some wavelengths of light emitted from said device.

15. The method of claim 11 wherein said lens-like features are capable of amplifying the luminance of at least some wavelengths of light emitted from said device.

16. The method of claim 11 wherein said planarizing layer is transparent.

17. The method of claim 12 wherein a serrating pattern is random.

18. The method of claim 11 wherein said lens-like features are created by patterning a surface of said anode layer which is not adjacent to said DBR stack.

19. The method of claim 18 wherein patterning includes at least one of:

dry etching, wet etching, lithography, stamping or sputtering.

20. An organic light emitting device, comprising:

a substrate;

a distributed Bragg reflector (DBR) stack on said substrate wherein said DBR stack is modified by creating lens-like features, said lens-like features not adjacent to said substrate; and

an anode layer on said DBR stack.

21. The device of claim 20 wherein said anode layer acts as a planarizing layer on said DBR stack, said planarizing layer filling in said lens-like features, said planarizing layer providing a flat uniform surface for deposition of other layers thereupon.

22. The device of claim 20 further comprising:

a planarizing layer on said DBR stack, said planarizing layer filling in said lens-like features, said planarizing layer providing a flat uniform surface for deposition of other layers thereupon.