Patent ID: 11899167
Assignee: TOYOBO CO., LTD.
Field: Other special machines (Mechanical engineering)
Classification: CPC C  G  B  H | IPC C  G  H

Claim 0:
1. A polyester film for protecting an organic EL module of a foldable display, the polyester film satisfying the following conditions:
(1) a refractive index in a bending direction is from 1.591 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/cm3 or more,
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,
wherein the polyester film is a biaxially stretched polyethylene terephthalate film,
wherein the polyester film comprises an easy-to-adhere layer on at least one surface thereof and a hard coating layer having a thickness of from 1 μm to 50 μm, and
wherein the hard coating layer is present on the easy-to-adhere layer on at least one surface of the polyester film.