Display device having a buffer layer comprising a plurality of sub layers and interfaces

Patent metadata

Field	Value
Publication number	US-11063240-B2
Application number	US-201916421187-A
Country	US
Kind code	B2
Filing date	May 23, 2019
Priority date	Mar 8, 2016
Publication date	Jul 13, 2021
Grant date	Jul 13, 2021

Abstract

A display device includes a display substrate including at least one step portion, and a thin film encapsulation layer above the display substrate, the thin film encapsulation layer including a buffer layer configured to reduce a height difference due to the at least one step portion and a barrier layer above the buffer layer, the buffer layer including a plurality of sub-layers and interfaces between the plurality of sub-layers, and the interfaces including a curved surface changing from a concave shape to a convex shape toward a portion overlapping the step portion from an outer portion of the step portion.

First claim

What is claimed is:

1. A display device comprising:
a display substrate comprising at least one step portion; and
a thin film encapsulation layer above the display substrate, the thin film encapsulation layer comprising a buffer layer, and
the buffer layer comprising a plurality of sub-layers and interfaces between the plurality of sub-layers, each one of the sub-layers comprising a first portion and a second portion between the first portion and the display substrate, a carbon content of each one of the sub-layers gradually increasing from the first portion toward the second portion,
wherein each of the plurality of sub-layers comprises about 20 to about 50 atomic % of silicon, about 10 to about 40 atomic % of oxygen, and about 30 to about 60 atomic % of carbon based on a total number of atoms of the silicon, the oxygen, and the carbon, and each of the plurality of sub-layers having a Young's modulus from about 2 to about 3 GPa.

2. The display device of claim 1 , wherein each of the plurality of sub-layers has a thickness from about 300 Å to about 10000 Å.

3. The display device of claim 1 , wherein an interval between two adjacent interfaces of the interfaces reduces toward a portion overlapping the step portion from an outer portion of the step portion.

4. The display device of claim 1 , wherein the buffer layer has a first thickness at a location spaced from the step portion and has a second thickness at a location overlapping the step portion, and wherein the second thickness is less than the first thickness and greater than or equal to 0.5 times the first thickness.

5. The display device of claim 1 , wherein an upper surface of the first portion forms an interface of the interfaces, and
wherein the first portion has a silicon content ratio greater than that of the second portion, and the first portion has a carbon content ratio less than that of the second portion.

6. The display device of claim 5 , wherein each of the plurality of sub-layers comprises about 30 to about 40 atomic % of the silicon, about 18 to about 28 atomic % of the oxygen, and about 40 to about 50 atomic % of the carbon based on the total number of atoms of the silicon, the oxygen, and the carbon.

7. The display device of claim 5 , wherein each of the plurality of sub-layers comprises about 33 to about 36 atomic % of the silicon, about 20 to about 23 atomic % of the oxygen, and about 42 to about 45 atomic % of the carbon based on the total number of atoms of the silicon, the oxygen, and the carbon.

8. The display device of claim 1 , wherein the display substrate comprises a base substrate and a display portion above the base substrate,
wherein the display portion comprises a plurality of display elements and a pixel-defining layer defining a light-emitting region of the plurality of display elements, and
wherein the at least one step portion comprises the pixel-defining layer.

9. The display device of claim 8 , further comprising a protective layer above the display portion, the protective layer comprising a same material as that of the buffer layer.

10. The display device of claim 9 , wherein each of the plurality of display elements comprises a first electrode, a second electrode, and an intermediate layer between the first and second electrodes, the intermediate layer comprising an organic emission layer, and
wherein the display substrate further comprises a capping layer between the first electrode and the protective layer, the capping layer having a refractive index greater than that of the protective layer.

11. The display device of claim 10 , wherein the protective layer has a refractive index from about 1.38 to about 1.5.

12. The display device of claim 9 , wherein the protective layer further comprises silicon carbide to which hydrogen is coupled.

13. The display device of claim 8 , wherein the thin film encapsulation layer further comprises a barrier layer above the buffer layer.

14. The display device of claim 13 , wherein the thin film encapsulation layer is configured to seal the display portion,
wherein the barrier layer comprises a first barrier layer and a second barrier layer overlapping each other with the buffer layer therebetween, and
wherein the first and second barrier layers comprise an inorganic layer.

15. The display device of claim 14 , wherein the first and second barrier layers contact each other at an outer portion of the buffer layer.

Assignees

• Samsung Display Co Ltd

Inventors

• Oh Minho
• Kim Jongwoo
• Moon Jiyoung
• Lee Seungjae
• Cho Yoonhyeung
• Joo Youngcheol
• Ha Jaeheung

Classifications

• H10K59/8731

  multilayered coatings having a repetitive structure, e.g. having multiple organic-inorganic bilayers · CPC title

• H10K50/844

  Encapsulations · CPC title

• G02F1/1362 Primary

  Active matrix addressed cells {(G02F1/134336, G02F1/134363 take precedence)} · CPC title

• H10D86/451

  characterised by the compositions or shapes of the interlayer dielectrics · CPC title

• H10D86/60

  wherein the TFTs are in active matrices · CPC title