Foldable display and portable terminal device

Patent metadata

Field	Value
Publication number	US-2022164003-A1
Application number	US-202017429147-A
Country	US
Kind code	A1
Filing date	Jan 15, 2020
Priority date	Feb 8, 2019
Publication date	May 26, 2022
Grant date	—

Abstract

Provided is a foldable display that is excellent in mass production applicability and unlikely to have image distortion at the folding portion of the display after repeated folding, as well as a mobile device equipped therewith. The foldable display contains a surface protection film and a polarizer. The surface protection film is composed of a polyester film, and the angle made by the slow axis of the polyester film with the absorption axis of the polarizer is 10 to 80°. The polyester film has a refractive index in the bending direction of 1.590 to 1.620, a refractive index in the direction of a folding portion of 1.670 to 1.700, a refractive index in the thickness direction of 1.520 or less, and a density of 1.380 g/cm3 or more, wherein the bending direction refers to a direction orthogonal to the folding portion of the polyester film to be folded.

First claim

1 . A foldable display comprising a surface protection film and a polarizer, wherein
the surface protection film comprises a polyester film, the angle made by the slow axis of the polyester film with the absorption axis of the polarizer is 10 to 80°, and the polyester film satisfies the following conditions: (1) the polyester film has a refractive index in the bending direction of 1.590 to 1.620, (2) the polyester film has a refractive index in the direction of a folding portion of 1.670 to 1.700, (3) the polyester film has a refractive index in the thickness direction of 1.520 or less, and (4) the polyester film has a density of 1.380 g/cm 3 or more, wherein the bending direction refers to a direction orthogonal to the folding portion of the polyester film to be folded.

2 . The foldable display according to claim 1 , wherein the polyester film has an in-plane retardation (Re) of 3000 to 30000 nm.

3 . The foldable display according to claim 1 , wherein the polyester film has a total light transmittance of 85% or more, a haze of 3% or less, and a maximum heat shrinkage of 6% or less.

4 . The foldable display according to claim 1 , comprising an easy-to-adhere layer on at least one surface of the polyester film.

5 . The foldable display according to claim 1 , comprising a hard coating layer having a thickness of 1 to 50 μm on at least one surface of the polyester film.

6 . A mobile device comprising the foldable display of claim 1 .

7 . The foldable display according to claim 2 , wherein the polyester film has a total light transmittance of 85% or more, a haze of 3% or less, and a maximum heat shrinkage of 6% or less.

8 . The foldable display according to claim 7 , comprising an easy-to-adhere layer on at least one surface of the polyester film.

9 . The foldable display according to claim 8 , comprising a hard coating layer having a thickness of 1 to 50 μm on at least one surface of the polyester film.

10 . A mobile device comprising the foldable display of claim 9 .

Assignees

• Toyo Boseki

Inventors

• Nishio Shotaro
• Kawai Kiwamu
• Shimizu Akira
• Ito Katsuya

Classifications

• H10K59/8791

  Arrangements for improving contrast, e.g. preventing reflection of ambient light · CPC title

• H10K59/873

  Encapsulations · CPC title

• G06F1/1652 Primary

  the display being flexible, e.g. mimicking a sheet of paper, or rollable · CPC title

• G02B5/3033 Primary

  in the form of a thin sheet or foil, e.g. Polaroid · CPC title

• Y02E10/549

  Organic PV cells · CPC title