| 摘要 |
A circularly polarizing plate includes a polarizing film, a first optically anisotropic layer, and a second optically anisotropic layer in this order, in which the first optically anisotropic layer contains a twisted aligned liquid crystal compound of which a helical axis is a thickness direction thereof, a helix angle of the liquid crystal compound is 28.6±10°, an absorption axis of the polarizing film and an in-plane slow axis of the second optically anisotropic layer are parallel or orthogonal to each other, Δnd and ReB(550) respectively fall in predetermined value ranges. The circularly polarizing plate can sufficiently suppress the mixing of black with other colors in a front direction when being stuck on a display apparatus. A retardation plate used for the circularly polarizing plate and an organic EL display apparatus that have the circularly polarizing plate are also provided. |
| 主权项 |
1. A circularly polarizing plate comprising a polarizing film, a first optically anisotropic layer, and a second optically anisotropic layer in this order, and satisfying a following requirement (A) or (B),
wherein the first optically anisotropic layer contains a twisted aligned liquid crystal compound of which a helical axis is a thickness direction of the first optically anisotropic layer, a helix angle of the liquid crystal compound in the first optically anisotropic layer is 28.6±10°, an absorption axis of the polarizing film and an in-plane slow axis of the second optically anisotropic layer are parallel or orthogonal to each other, a value of Δnd, which is a product of a refractive index anisotropy Δn of the first optically anisotropic layer measured at a wavelength of 550 nm and a thickness d of the first optically anisotropic layer, satisfies a following expression (1), and ReB(550), which is a value of retardation of the second optically anisotropic layer measured at a wavelength of 550 nm, satisfies a following expression (2):
256 nm≦Δnd≦316 nm; expression (1)67.5 nm≦ReB(550)≦127.5 nm; expression (2) requirement (A): on condition that the circularly polarizing plate is observed from a side of the polarizing film, counter-clockwise rotation is indicated by a positive angular value, based on an in-plane slow axis (0°) of the second optically anisotropic layer, the in-plane slow axis in a surface, which is on a side of the second optically anisotropic layer, of the first optically anisotropic layer is within a range of 33.6±10°, and the liquid crystal compound in the first optically anisotropic layer forms a counter-clockwise helix; or requirement (B): on condition that the circularly polarizing plate is observed from the side of the polarizing film, counter-clockwise rotation is indicated by a positive angular value, based on the in-plane slow axis (0°) of the second optically anisotropic layer, the in-plane slow axis in a surface, which is on the side of the second optically anisotropic layer, of the first optically anisotropic layer is within a range of −33.6±10°, and the liquid crystal compound in the first optically anisotropic layer forms a clockwise helix. |
