Polyester film and flexible display apparatus comprising same
AssigneeSkc Co., Ltd.
InventorsGun Uk Kim, Sang Min Choi, Young Min Heo
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Abstract
The polyester film according to an embodiment has a coefficient of determination (R2) of the strain with respect to stress and a crystallinity adjusted to specific ranges, whereby it is possible to achieve the flexibility that does not cause deformation even when a certain stress is sustained for a long period of time and the resistant characteristics to the impact of external pressing. Accordingly, the polyester film can be applied to a cover of a flexible display device, in particular, a foldable display device to exhibit excellent characteristics.
Claims11
A polyester film having a coefficient of determination (R2) of 0.985 or more in first and second directions perpendicular to each other in a plane, respectively, in the section in which the strain is 2% to 3% in the stress-strain curve and having a crystallinity of 55% or more,
- wherein the polyester film has a difference between the stress at a strain of 2% and the stress at a strain of 4% in the stress-strain curve of 10 MPa or more.
A laminate, which comprises a transparent cover for a flexible display device;
- and a polyester film disposed on the transparent cover,
- wherein the polyester film has a coefficient of determination (R2) of 0.985 or more in first and second directions perpendicular to each other in a plane, respectively, in the section in which the strain is 2% to 3% in the stress-strain curve and has a crystallinity of 55% or more,
- wherein the polyester film has a difference between the stress at a strain of 2% and the stress at a strain of 4% in the stress-strain curve of 10 MPa or more.
A flexible display device, which comprises a flexible display panel;
- and a polyester film disposed on the flexible display panel,
- wherein the polyester film has a coefficient of determination (R2) of 0.985 or more in first and second directions perpendicular to each other in a plane, respectively, in the section in which the strain is 2% to 3% in the stress-strain curve and has a crystallinity of 55% or more
- wherein the polyester film has a difference between the stress at a strain of 2% and the stress at a strain of 4% in the stress-strain curve of 10 MPa or more.
Dependencies are inferred from the claim text.