Polyimide film, flexible substrate using same, and flexible display comprising flexible substrate
US11472922B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 15, 2019 |
| Grant date | Oct 18, 2022 |
| Priority date | — |
| Expiry date | Nov 20, 2039 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08L2203/16
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
According to the present invention, damage such as film tearing during a rolling process can be reduced by using, as a substrate for a flexible display, a polyimide film having the thickness of 5-10 μm, modulus of 3-8 GPa, the absolute value of out-of-plane retardation (Rth) of 200-600 nm, and a strain, at a tensile force of 100 MPa, of 10% or less. In addition, since the polyimide film has low residual stress with respect to inorganic substrates, the occurrence of defects during a TFT process is reduced. As a result, processing reliability for a flexible display can be improved. In addition, the saturated static electricity half-life of the polyimide film is controlled to be 250 seconds or more so as to minimize the voltage loss ratio of saturated static electricity and reduce the current drop during a TFT operation, and, as a result, enables a display having improved luminosity to be provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.