US 12,235,482 B2
Optical film, retarder film, and method for manufacturing same
Kazuki Kumazawa, Tokyo (JP); and Hironari Sudeji, Tokyo (JP)
Assigned to ZEON CORPORATION, Tokyo (JP)
Appl. No. 17/294,462
Filed by ZEON CORPORATION, Tokyo (JP)
PCT Filed Nov. 8, 2019, PCT No. PCT/JP2019/043993
§ 371(c)(1), (2) Date May 17, 2021,
PCT Pub. No. WO2020/110672, PCT Pub. Date Jun. 4, 2020.
Claims priority of application No. 2018-225554 (JP), filed on Nov. 30, 2018.
Prior Publication US 2022/0011490 A1, Jan. 13, 2022
Int. Cl. G02B 5/30 (2006.01); B29C 48/00 (2019.01); B29C 48/08 (2019.01); B29C 71/02 (2006.01); C08L 53/02 (2006.01); B29K 96/04 (2006.01)
CPC G02B 5/3083 (2013.01) [B29C 48/0018 (2019.02); B29C 48/08 (2019.02); B29C 71/02 (2013.01); C08L 53/025 (2013.01); B29K 2096/04 (2013.01); B29K 2995/0034 (2013.01); C08L 2203/16 (2013.01)] 20 Claims
 
1. An optical film formed of a resin C including a copolymer P containing a polymerization unit A and a polymerization unit B, wherein
the optical film includes a phase separation structure that expresses structural birefringence,
the phase separation structure includes a phase (A) containing as a main component the polymerization unit A and a phase (B) containing as a main component the polymerization unit B,
an absolute value |n(A)−n(B)| of a difference between a refractive index n (A) of a polymer (A) formed of the polymerization unit A and a refractive index n(B) of a polymer (B) formed of the polymerization unit B is 0.12 or more, and
a value of Rth/d is 0.5×10−3 or more wherein the Rth represents a thickness-direction retardation of the optical film and the d represents a thickness of the optical film.