Light emitting device and display apparatus including the same

Patent metadata

Field	Value
Publication number	US-2020058905-A1
Application number	US-201916263080-A
Country	US
Kind code	A1
Filing date	Jan 31, 2019
Priority date	Aug 20, 2018
Publication date	Feb 20, 2020
Grant date	—

Abstract

A light emitting device and a display apparatus including a phase shifting mirror are provided. The light emitting device includes a first electrode, a light emitting structure, a second electrode, and a phase shifting mirror. The phase shifting mirror has a number of patterns arranged in a periodic manner with an interval between adjacent patterns. Each pattern has a top surface and a side surface between the top surface of the respective pattern and the top surface of the first electrode. A first width at a bottom portion of the respective pattern directly adjacent to the top surface of the first electrode is greater than a second width of the top surface of the respective pattern, and the first width and the second width are less than a wavelength of light generated in the light emitting structure

First claim

What is claimed is:

1 . A light emitting device comprising:
a first electrode; a light emitting structure disposed on the first electrode; a second electrode disposed on the light emitting structure; and a phase shifting mirror formed on a top surface of the first electrode, the phase shifting mirror comprising a plurality of patterns arranged in a periodic manner with an interval between adjacent patterns, wherein each of the plurality of patterns comprises a top surface and a side surface between the top surface of the respective pattern and the top surface of the first electrode, wherein a first width at a bottom portion of the respective pattern directly adjacent to the top surface of the first electrode is greater than a second width of the top surface of the respective pattern, and wherein the first width and the second width are less than a wavelength of light generated in the light emitting structure.

2 . The light emitting device of claim 1 ,
wherein the phase shifting mirror and the second electrode constitute a resonator having a resonance wavelength, and wherein the resonance wavelength of the resonator is determined according to at least one of the first width, the second width, a depth of each of the plurality of patterns, and an arrangement period of the plurality of patterns.

3 . The light emitting device of claim 2 , wherein when the resonance wavelength of the resonator is λ, at least one of the first width, the second width, the depth of each of the plurality of patterns, and the arrangement period of the plurality of patterns is selected such that an optical length of the resonator satisfies nλ/2, n is a natural number.

4 . The light emitting device of claim 1 , wherein the second electrode is a transflective electrode that reflects a part of light and transmits another part of the light.

5 . The light emitting device of claim 1 , wherein the side surface of each of the plurality of patterns is an inclined surface.

6 . The light emitting device of claim 1 , wherein each of the plurality of patterns has a rod shape extending in a first direction, and the plurality of patterns are arranged along a second direction perpendicular to the first direction.

7 . The light emitting device of claim 1 , wherein each of the plurality of patterns has a truncated conical shape or a truncated polygonal pyramid shape, and the plurality of patterns are two-dimensionally arranged.

8 . The light emitting device of claim 1 ,
wherein the first electrode comprises a reflective metal material, and wherein the phase shifting mirror comprises a same reflective metal material as the first electrode.

9 . The light emitting device of claim 1 ,
wherein the first electrode comprises a reflective metal material, and wherein the phase shifting mirror comprises a different reflective metal material from the first electrode.

10 . The light emitting device of claim 1 , wherein a sum of the first width and the second width is less than the wavelength of the light generated in the light emitting structure.

11 . The light emitting device of claim 1 , wherein a sum of the first width and the second width is less than 1/3 of the wavelength of the light generated in the light emitting structure.

12 . The light emitting device of claim 1 , wherein the light emitting structure comprises:
a hole injection layer disposed on the first electrode; a hole transport layer disposed on the hole injection layer; an organic emission layer disposed on the hole transport layer; an electron transport layer disposed on the organic emission layer; and an electron injection layer disposed on the electron transport layer.

13 . The light emitting device of claim 1 , further comprising:
a dielectric layer is formed between the plurality of patterns of the phase shifting mirror.

14 . The light emitting device of claim 13 ,
wherein the dielectric layer is configured to completely cover top surfaces of the plurality of patterns, and wherein the light emitting device further comprises: a transparent electrode disposed between the dielectric layer and the light emitting structure.

15 . The light emitting device of claim 14 , further comprising:
a wiring configured to electrically connect the first electrode to the transparent electrode.

16 . The light emitting device of claim 1 , further comprising:
a transparent electrode disposed between the phase shifting mirror and the light emitting structure.

17 . A display apparatus comprising:
a first pixel configured to emit light of a first wavelength; and a second pixel configured to emit light of a second wavelength different from the first wavelength, wherein the first pixel comprises: a first electrode; a first light emitting structure disposed on the first electrode; a second electrode disposed on the first light emitting structure; and a first phase shifting mirror formed on a top surface of the first electrode, the first phase shifting mirror comprising a plurality of patterns arranged in a periodic manner, wherein each of the plurality of patterns comprises a top surface and a side surface between the top surface of the respective pattern and the top surface of the first electrode, wherein a first width at a bottom portion of the respective pattern directly adjacent to the top surface of the first electrode is greater than a second width of the top surface of the respective pattern, and wherein the first width and the second width are less than a wavelength of light generated in the first light emitting structure.

18 . The display apparatus of claim 17 ,
wherein the first phase shifting mirror and the second electrode constitute a first resonator having a resonance wavelength, and wherein a distance between the second electrode and the top surface of each of the plurality of patterns, the first width of each of the plurality of patterns, the second width of each of the plurality of patterns, and a depth of each of the plurality of patterns are selected such that the resonance wavelength of the first resonator is identical to the first wavelength.

19 . The display apparatus of claim 18 , wherein the second pixel comprises:
a third electrode; a second light emitting structure disposed on the third electrode; and a fourth electrode disposed on the second light emitting structure.

20 . The display apparatus of claim 19 ,
wherein the third electrode and the fourth electrode constitute a second resonator having a resonance wavelength, and wherein a distance between the third electrode and the fourth electrode is selected such that the resonance wavelength of the second resonator is identical to the second wavelength.

21 . The display apparatus of claim 20 , wherein a distance between the second electrode and the top surface of each of the plurality of patterns and the distance between the third electrode and the fourth electrode are same.

22 . The display apparatus of claim 19 , wherein both the first light emitting structure and the second light emitting structure are configured to emit white visible light.

23 . The display apparatus of claim 18 , further comprising:
a third pixel configured to emit light of a third wavelength different from the first wavelength and the second wavelength, wherein the third pixel comprises: a fifth electrode; a third light emitting structure disposed on the fifth electrode; a sixth electrode disposed on t

Assignees

• Samsung Electronics Co Ltd

Inventors

• Kyoung Jisoo
• Joo Wonjae
• Kwon Youngnam
• Song Byonggwon

Classifications

• H01L51/5225

  Electricity · mapped topic

• H01L51/5092

  Electricity · mapped topic

• H01L27/3244

  Electricity · mapped topic

• H01L51/5056

  Electricity · mapped topic

• H01L51/5096

  Electricity · mapped topic