Organic light-emitting display apparatus including nano-structured mirror

Patent metadata

Field	Value
Publication number	US-11038148-B2
Application number	US-201916695404-A
Country	US
Kind code	B2
Filing date	Nov 26, 2019
Priority date	Jan 16, 2019
Publication date	Jun 15, 2021
Grant date	Jun 15, 2021

Abstract

An OLED apparatus includes a plurality of blue pixels configured to emit blue light, a plurality of green pixels configured to emit green light, and a plurality of red pixels configured to emit red light. Each of the plurality of blue, green, and red pixels includes a reflection layer; a first electrode arranged on the reflection layer; a light-emitting region arranged on the first electrode; and a second electrode arranged on the light-emitting region. An upper surface of the reflection layer of the blue pixel is continuously flat, and an upper surface of the reflection layer of the green pixel and an upper surface of the reflection layer of the red pixel are level with each other. Each of the green pixel or each of the red pixel includes a plurality of nano-structures protruding from a bottom surface of the reflection layer to the upper surface of the reflection layer.

First claim

What is claimed is:

1. A display apparatus comprising a plurality of blue pixels configured to emit blue light, a plurality of green pixels configured to emit green light, and a plurality of red pixels configured to emit red light, each of the plurality of blue, green, and red pixels comprising:
a reflection layer;
a first electrode arranged on the reflection layer;
a light-emitting region arranged on the first electrode; and
a second electrode arranged on the light-emitting region,
wherein an upper surface of the reflection layer of each of the plurality of blue pixels is continuously flat, and is level with an upper surface of the reflection layer of the green pixel and an upper surface of the reflection layer of the red pixel,
wherein each of the plurality of green pixels or each of the plurality of red pixels comprises a plurality of nano-structures protruding from a bottom surface of the reflection layer to the upper surface of the reflection layer, and
wherein the plurality of nano-structures have same level and length as each other.

2. The display apparatus of claim 1 , wherein a depth of the nano-structures is in a range from about 70 nm to about 80 nm.

3. The display apparatus of claim 1 , wherein the plurality of nano-structures comprise circular columns.

4. The display apparatus of claim 3 , wherein the nano-structures are periodically and regularly arranged.

5. The display apparatus of claim 3 , wherein the circular columns of the green pixels have a first diameter and a first pitch greater than a second diameter and a second pitch of the circular columns of the red pixels.

6. The display apparatus of claim 5 , wherein the first diameter is in a range from about 150 nm to about 250 nm and the first pitch is in a range from about 350 nm to about 450 nm.

7. The display apparatus of claim 5 , wherein the second diameter is in a range from about 50 nm to about 150 nm and the second pitch is in a range from about 200 nm to about 300 nm.

8. The display apparatus of claim 1 , wherein the first electrode of each of the red pixels, the green pixels and the blue pixels are separated from each other, and the second electrode is a common electrode.

9. The display apparatus of claim 1 , wherein the first electrode is a transparent electrode, and the second electrode is a semi-transparent electrode configured to reflect a portion of light and transmit a remaining portion of the light.

10. The display apparatus of claim 9 , wherein the second electrode comprises a reflective metal and has a thickness in a range from about 10 nm to about 20 nm.

11. The display apparatus of claim 10 , wherein the reflection layer comprises Ag or an alloy including Ag.

12. The display apparatus of claim 1 , wherein the first electrode is arranged in areas between the plurality of nano-structures.

13. The display apparatus of claim 1 , further comprising:
a dielectric material is arranged in areas between the plurality of nano-structures.

14. The display apparatus of claim 1 , further comprising:
a dielectric layer that is arranged between the reflection layer and the first electrode,
wherein the dielectric layer is arranged in areas between the nano-structures of the green pixels and the red pixels.

15. The display apparatus of claim 1 , wherein the light-emitting region comprises:
a hole injection layer arranged on the first electrode;
a hole transfer layer arranged on the hole injection layer;
an organic emissive layer arranged on the hole transfer layer and configured to generate blue light, green light, and red light;
an electron transfer layer arranged on the organic emissive layer; and
an electron injection layer arranged on the electron transfer layer.

16. The display apparatus of claim 1 , wherein the light-emitting regions of the blue pixel, the green pixel, and the red pixel are continuously formed.

17. The display apparatus of claim 1 , wherein the light-emitting region is configured to emit white light.

18. The display apparatus of claim 1 , further comprising:
a cap layer arranged on the second electrode.

19. A method of manufacturing a display apparatus, the method comprising:
forming a reflection layer on a substrate;
forming a first electrode on the reflection layer;
forming a light-emitting region on the first electrode; and
forming a second electrode on the light-emitting region,
wherein the forming a reflection layer on a substrate comprises forming flatwise a region of the reflection layer corresponding to a blue pixel and a plurality of protrusions in a region of the reflection layer corresponding to green and red pixels, and
wherein the plurality of nano-structures have same level and length as each other.

20. The method of claim 19 , wherein the reflection layer is in contact with the first electrode.

21. The method of 20 , wherein areas between the plurality of protrusions are filled with the first electrode.

22. The method of claim 19 , further comprising forming a dielectric layer between the reflection layer and the first electrode, the dielectric layer filling areas between the plurality of protrusions.

23. The method of claim 19 , wherein a width of the protrusions in the region corresponding to the green pixel is different from that of the protrusions in the region corresponding to the red pixel.

24. The method of claim 23 , wherein the protrusions in the region corresponding to the green pixel have a first diameter and a first pitch greater than a second diameter and a second pitch of the protrusions in the region corresponding to the red pixel.

25. The method of claim 19 , wherein the plurality of protrusions include nano-structures periodically and regularly arranged.

26. The method of claim 19 , wherein the first electrode includes a first portion corresponding to the red pixel, a second portion corresponding to the green pixel and a third portion corresponding to the blue pixel, the first to third portions being separated from each other.

27. The method of claim 19 , wherein the first electrode is a transparent electrode, and the second electrode is a semi-transparent electrode configured to reflect a portion of light and transmit a remaining portion of the light.

28. The method of claim 27 , wherein the second electrode comprises a reflective metal and has a thickness in a range from about 10 nm to about 20 nm.

29. The method of claim 19 , wherein the light-emitting region comprises:
a hole injection layer arranged on the first electrode;
a hole transfer layer arranged on the hole injection layer;
an organic emissive layer arranged on the hole transfer layer and configured to generate blue light, green light, and red light;
an electron transfer layer arranged on the organic emissive layer; and
an electron injection layer arranged on the electron transfer layer.

30. The method of claim 19 , wherein the light-emitting regions of the blue pixel, the green pixel, and the red pixel are continuously formed.

31. The method of claim 19 , wherein the light-emitting region is configured to emit white light.

32. The method of claim 19 , further comprising:
forming a cap layer on the second electrode.

Assignees

• Samsung Electronics Co Ltd

Inventors

• Kyoung Jisoo
• Joo Wonjae

Classifications

• H10K59/805

  Electrodes · CPC title

• H10K71/00

  Manufacture or treatment specially adapted for the organic devices covered by this subclass · CPC title

• H10K50/125

  specially adapted for multicolour light emission, e.g. for emitting white light · CPC title

• H10K59/878 Primary

  comprising reflective means · CPC title

• H10K59/876

  comprising a resonant cavity structure, e.g. Bragg reflector pair · CPC title