US 11,655,338 B2
Polyimide film and flexible display panel including the same
Jin Su Park, Daejeon (KR); Min Sang Park, Daejeon (KR); Hyun Joo Song, Daejeon (KR); and Suk Chin Lee, Daejeon (KR)
Assigned to SK Innovation Co., Ltd., Seoul (KR); and SK ie technology Co., Ltd., Seoul (KR)
Filed by SK Innovation Co., Ltd., Seoul (KR); and SK ie technology Co., Ltd, Seoul (KR)
Filed on Jun. 16, 2021, as Appl. No. 17/349,102.
Claims priority of application No. 10-2020-0073427 (KR), filed on Jun. 17, 2020.
Prior Publication US 2021/0395460 A1, Dec. 23, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. C08G 73/14 (2006.01); C08J 5/18 (2006.01)
CPC C08G 73/14 (2013.01) [C08J 5/18 (2013.01); C08J 2379/08 (2013.01)] 12 Claims
 
1. A polyimide-based film having different surface properties, wherein when a strength of one surface of both surfaces is 100%, a strength of the other surface is 40 to 80% of the strength of the one surface, the strength being quantified by a ratio of an aromatic ring peak intensity measured by Raman spectroscopic analysis,
wherein the polyimide-based film has a light transmittance of 5% or more as measured at 388 nm according to ASTM D1746, a total light transmittance of 87% or more as measured at 400 to 700 nm, a haze of 2.0% or less, a yellow index of 5.0 or less, and a b* value of 2.0 or less.