Patent ID: 11970562
Assignee: ZEON CORPORATION
Field: Other special machines (Mechanical engineering)
Classification: CPC C  B  G | IPC B  C  G

Claim 0:
1. A phase difference film composed of a resin C containing a copolymer P wherein the copolymer P is a block polymer including a block (A) having a polymerization unit A as a main component and a block (B) having a polymerization unit B as a main component,
the phase difference film including a cylindrical phase separation structure that generates a structural birefringence,
the phase separation structure including a phase (A) having the polymerization unit A as a main component and a phase (B) having the polymerization unit B as a main component,
an interphase distance in the phase separation structure is 200 nm or less, and

the phase difference film satisfying the following condition (1) or (2),
Condition (1): D(A)>D(B) and f(B)>0.5, and a direction giving a maximum refractive index among in-plane directions and an orientation direction of a cylinder in the phase separation structure are parallel to each other, and
Condition (2): D(A)>D(B) and 0.80>f(A)>0.5, and a direction giving a maximum refractive index among in-plane directions and an orientation direction of a cylinder in the phase separation structure are orthogonal to each other,
wherein
f(A) represents a total weight ratio of the polymerization unit A in the copolymer P,
f(B) represents a total weight ratio of the polymerization unit B in the copolymer P,
D(A)=ReA(450)/ReA(550),
D(B)=ReB (450)/ReB (550),
ReA(450) represents an in-plane direction retardation (nm) of a film (A) formed from a polymer (A) composed of the polymerization unit A measured at a wavelength of 450 nm,
ReA(550) represents an in-plane direction retardation (nm) of the film (A) measured at a wavelength of 550 nm,
ReB(450) represents an in-plane direction retardation (nm) of a film (B) formed from a polymer (B) composed of the polymerization unit B measured at a wavelength of 450 nm,
ReB(550) represents an in-plane direction retardation (nm) of the film (B) measured at a wavelength of 550 nm,
the polymerization unit A is an aromatic vinyl-based unit, and
the polymerization unit B is a hydrogenated chain conjugated diene-based unit.