Flexible display apparatus

Patent metadata

Field	Value
Publication number	US-10401675-B2
Application number	US-201715646044-A
Country	US
Kind code	B2
Filing date	Jul 10, 2017
Priority date	Nov 28, 2016
Publication date	Sep 3, 2019
Grant date	Sep 3, 2019

Abstract

A flexible display apparatus includes a bending area and a non-bending area. The flexible display apparatus further includes a display panel and a polarizing structure disposed on the display panel. The polarizing structure includes a λ/4 phase retardation layer, a linear polarizer disposed on the λ/4 phase retardation layer, and a first adhesive structure disposed between the λ/4 phase retardation layer and the linear polarizer. The linear polarizer includes a stretched polymer film. The first adhesive structure is an adhesive layer with a glass transition temperature that is greater than or equal to 40° C. and less than or equal to 150° C. Accordingly, deformation of the λ/4 phase retardation layer may be prevented or reduced when the flexible display apparatus is folded or bent, thereby improving display quality.

First claim

What is claimed is:

1. A flexible display apparatus comprising a bending area and a non-bending area, the flexible display apparatus further comprising:
a display panel; and
a polarizing structure disposed on the display panel,
wherein the polarizing structure comprises:
a liquid crystal coating layer forming a phase retardation layer;
a linear polarizer disposed on the liquid crystal coating layer, the linear polarizer comprising a stretched polymer film;
a first adhesive structure disposed directly on a first surface of the liquid crystal coating layer, the first adhesive structure being an adhesive layer with a glass transition temperature that is greater than or equal to 40° C. and less than or equal to 150° C.;
a second adhesive structure disposed directly on a second surface of the liquid crystal coating layer opposing the first surface of the liquid crystal coating layer, the second adhesive structure being an adhesive layer with a glass transition temperature that is greater than or equal to −35° C. and less than or equal to 0° C.;
another phase retardation layer disposed on the liquid crystal coating layer;
a first optical compensation layer disposed directly on the second adhesive structure;
a second optical compensation layer disposed directly on the first adhesive structure, the second optical compensation layer being disposed between the liquid crystal coating layer and the another phase retardation layer;
a third adhesive structure disposed between the linear polarizer and the another phase retardation layer; and
a fourth adhesive structure disposed between the another phase retardation layer and the second optical compensation layer,

wherein the third adhesive structure is:
a pressure sensitive adhesive layer with a glass transition temperature that is greater than or equal to −35° C. and less than or equal to 0° C., or
an adhesive layer with a glass transition temperature that is greater than or equal to 40° C. and less than or equal to 150° C., and

wherein:
the phase retardation layer is a λ/4 phase retardation layer;
the another phase retardation layer is a λ/2 phase retardation layer; and
the fourth adhesive structure is an adhesive layer with a glass transition temperature that is greater than or equal to 40° C. and less than or equal to 150° C.

2. The flexible display apparatus of claim 1 , wherein a thickness of the first adhesive structure is greater than or equal to 0.1 μm and less than or equal to 5 μm.

3. The flexible display apparatus of claim 1 , wherein:
the first adhesive structure comprises an ultraviolet curable adhesive; and
the second adhesive structure comprises a pressure sensitive adhesive.

4. The flexible display apparatus of claim 1 , wherein a thickness of the liquid crystal coating layer is greater than or equal to 0.5 μm and less than or equal to 5 μm.

5. The flexible display apparatus of claim 1 , wherein each of the first optical compensation layer and the second optical compensation layer is a positive C-plate or a negative C-plate.

6. The flexible display apparatus of claim 1 , wherein, in a plan view, an angle between an absorption axis or a transmission axis of the linear polarizer and a first optical axis of the liquid crystal coating layer is 45 degrees±30 degrees.

7. The flexible display apparatus of claim 1 , wherein, in a plan view:
an angle between an absorption axis or a transmission axis of the linear polarizer and a first optical axis of the liquid crystal coating layer is 75 degrees±30 degrees; and
an angle between the absorption axis or the transmission axis and a second optical axis of the another phase retardation layer is 15 degrees±13 degrees.

8. The flexible display apparatus of claim 1 , wherein, in a plan view, an angle between a first optical axis of the liquid crystal coating layer and a second optical axis of the another phase retardation layer is 60 degrees±30 degrees.

9. The flexible display apparatus of claim 1 , wherein:
the liquid crystal coating layer is a nematic liquid crystal coating layer; and
the another phase retardation layer is a discotic liquid crystal coating layer.

10. The flexible display apparatus of claim 1 , wherein:
in a first mode, the display panel and the polarizing structure are bent with respect to a bending axis such that the polarizing structure is disposed closer to the bending axis than the display panel; and
in a second mode, the display panel and the polarizing structure are unfolded.

11. The flexible display apparatus of claim 1 , wherein:
in a third mode, the display panel and the polarizing structure are bent with respect to a bending axis such that the display panel is disposed closer to the bending axis than the polarizing structure; and
in a fourth mode, the display panel and the polarizing structure are unfolded.

12. The flexible display apparatus of claim 1 , wherein the bending area is bent from one side of the non-bending area.

13. The flexible display apparatus of claim 1 , wherein a radius of curvature of the bending area is greater than 0 mm and less than or equal to 5 mm.

14. The flexible display apparatus of claim 1 , further comprising:
a touch sensing structure disposed on the display panel,
wherein the touch sensing structure is disposed on an upper surface or a lower surface of the polarizing structure.

15. The flexible display apparatus of claim 1 , wherein at least one of a degree of polymerization and a degree of cross-linking of the first adhesive structure is different from that of the second adhesive structure.

Assignees

• Samsung Display Co Ltd

Inventors

• Lee Heeyoung
• Seo Eunmi

Classifications

• G02B5/3083

  Birefringent or phase retarding elements (G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001) · CPC title

• G09F9/301 Primary

  flexible foldable or roll-able electronic displays, e.g. thin LCD, OLED · CPC title

• G02F2202/28

  Adhesive materials or arrangements · CPC title

• G06F1/1641

  the display being formed by a plurality of foldable display components (G06F1/1647 takes precedence) · CPC title

• G02B1/18

  Coatings for keeping optical surfaces clean, e.g. hydrophobic or photo-catalytic films (G02B1/16 takes precedence) · CPC title