Granted Patent B2

US 12,354,504 · App. 17/614,260 · Granted Jul 8, 2025

Inventors: Shotaro Nishio (Tsuruga, JP); Kiwamu Kawai (Tsuruga, JP); Mei Matsumura (Tsuruga, JP); Akira Shimizu (Tsuruga, JP)

Assignee: TOYOBO CO., LTD.

G09F9/301C08J7/044C08J7/046G06F3/041B32B2255/26B32B2307/412B32B2307/418B32B2307/518B32B2307/72B32B2307/734C08J2367/02G06F2203/04102

Abstract

Claims (18)

1. A foldable organic EL display comprising a transparent conductive polyester film, comprising:

a polyester film; and

a transparent conductive layer laminated on at least one surface of the polyester film, wherein the polyester film satisfies the following conditions:

(1) a refractive index in a bending direction is from 1.590 to 1.606;

(2) a refractive index in a folding portion direction is from 1.670 to 1.700;

(3) a refractive index in a thickness direction is 1.520 or less; and

(4) a density is 1.380 g/cm 3 or more,

wherein the polyester film is a biaxially stretched polyethylene terephthalate film, and

wherein the bending direction refers to a direction orthogonal to a folding portion of the polyester film at a time when the polyester film is folded.

2. The foldable organic EL display according to claim 1 , wherein the transparent conductive layer contains at least one kind selected from: a conductive fibrous filler; a metal oxide; and a conductive polymer.

3. A mobile device comprising the foldable organic EL display of claim 2 .

4. The foldable organic EL 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 ratio of 6% or less, wherein the maximum heat shrinkage ratio is determined for a sample of the polyester film having a length of 10 mm and a width of 250 mm by (a) marking the sample at an interval of 200 mm, (b) measuring an interval A between the marks under constant tension of 5 g, (c) allowing the sample to stand under no load in an oven at 150° C. for 30 minutes, (d) cooling the sample to room temperature, (e) subsequently measuring an interval B between the marks under constant tension of 5 g, and (f) calculating the heat shrinkage ratio as the value of [(interval A−internal B)×100]/interval A.

5. A mobile device comprising the foldable organic EL display of claim 4 .

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

7. A mobile device comprising the foldable organic EL display of claim 6 .

8. The foldable organic EL display according to claim 1 , wherein the polyester film comprises a hard coating layer having a thickness of from 1 μm to 50 μm on at least one surface thereof.

9. A mobile device comprising the foldable organic EL display of claim 8 .

10. A mobile device comprising the foldable organic EL display of claim 1 .

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (273)

Cited By (1)

US 12,663,834