Patent ID: 8952600
Filing Date: 2015-02-10
Classification: G02B

Abstract:
1. A circularly polarizing plate comprising a polarizer and two λ/4 plates bonded on both sides of the polarizer so as to face each other, wherein in-plane retardation values Ro of one λ/4 plate (referred to as “λ/4 plate T1”, hereinafter) and other λ/4 plate (referred to as “λ/4 plate T2”, hereinafter) satisfy following conditions (a) to (c), when measured in an environment with a temperature of 23° C. and a relative humidity of 55%: (a) the in-plane retardation value Ro of the λ/4 plate T1 is 3.0 to 20.0 nm smaller than the in-plane retardation value Ro of the λ/4 plate T2, when measured in the range from 450 to 650 nm; (b) the in-plane retardation value Ro(450) of the λ/4 plate T1 measured at a measurement wavelength of 450 nm falls in the range from 110 to 140 nm; and (c) the in-plane retardation value Ro(650) of the λ/4 plate T2 measured at a measurement wavelength of 650 nm falls in the range from 145 to 165 nm.