Phase difference film, circularly polarizing plate, and display device

Patent metadata

Field	Value
Publication number	US-2024118474-A1
Application number	US-202318511449-A
Country	US
Kind code	A1
Filing date	Nov 16, 2023
Priority date	Jun 1, 2021
Publication date	Apr 11, 2024
Grant date	—

Abstract

A phase difference film includes a small change in tint when the film is applied to a display device as a circularly polarizing plate in combination with a polarizer display device being observed from an oblique direction at all azimuthal angles. The film includes optically anisotropic layers X, Y, and Z in this order, in which layer X is an A-plate, and layers Y and Z are formed by fixing a first and second liquid crystal compound, respectively, twist-aligned along a helical axis extending in a thickness direction, one of the first and second liquid crystal compounds are rod-like liquid crystal compounds, the other first and the second liquid crystal compounds are disk-like liquid crystal compounds, and an in-plane slow axis of layer X is parallel to an in-plane slow axis on a surface of layer Y on layer X side.

First claim

What is claimed is:

1 . A phase difference film comprising, in the following order:
an optically anisotropic layer X; an optically anisotropic layer Y; and an optically anisotropic layer Z, wherein the optically anisotropic layer X is an A-plate, the optically anisotropic layer Y is a layer formed by fixing a first liquid crystal compound twist-aligned along a helical axis extending in a thickness direction, the optically anisotropic layer Z is a layer formed by fixing a second liquid crystal compound twist-aligned along a helical axis extending in a thickness direction, one of the first liquid crystal compound and the second liquid crystal compound is a rod-like liquid crystal compound, and the other of the first liquid crystal compound and the second liquid crystal compound is a disk-like liquid crystal compound, and an in-plane slow axis of the optically anisotropic layer X is parallel to an in-plane slow axis on a surface of the optically anisotropic layer Y on an optically anisotropic layer X side.

2 . The phase difference film according to claim 1 ,
wherein the optically anisotropic layer X includes a positive A-plate and a negative A-plate, in a case where the positive A-plate and the negative A-plate are disposed in this order from a surface of the optically anisotropic layer X opposite to an optically anisotropic layer Y side, the first liquid crystal compound is a rod-like liquid crystal compound, and the second liquid crystal compound is a disk-like liquid crystal compound, and in a case where the negative A-plate and the positive A-plate are disposed in this order from the surface of the optically anisotropic layer X opposite to the optically anisotropic layer Y side, the first liquid crystal compound is a disk-like liquid crystal compound, and the second liquid crystal compound is a rod-like liquid crystal compound.

3 . The phase difference film according to claim 2 ,
wherein an in-plane retardation at a wavelength of 550 nm of the A-plate on the side of the optically anisotropic layer X opposite to the optically anisotropic layer Y side is 20 to 90 nm, and an in-plane retardation at a wavelength of 550 nm of the A plate of the optically anisotropic layer X on the optically anisotropic layer Y side is 70 to 200 nm.

4 . The phase difference film according to claim 2 ,
wherein a twisted angle of the first liquid crystal compound is within a range of 40°±20°.

5 . The phase difference film according to claim 2 ,
wherein a twisted angle of the second liquid crystal compound is within a range of 40°±20°.

6 . The phase difference film according to claim 2 ,
wherein a value of a product Δnd of a refractive index anisotropy Δn of the optically anisotropic layer Y at a wavelength of 550 nm and a thickness d of the optically anisotropic layer Y is 50 to 120 nm.

7 . The phase difference film according to claim 2 ,
wherein a value of a product Δnd of a refractive index anisotropy Δn of the optically anisotropic layer Z at a wavelength of 550 nm and a thickness d of the optically anisotropic layer Z is 50 to 120 nm.

8 . The phase difference film according to claim 1 ,
wherein the optically anisotropic layer X is a positive A-plate or a negative A-plate, in a case where the optically anisotropic layer X is a positive A-plate, the first liquid crystal compound is a disk-like liquid crystal compound, and the second liquid crystal compound is a rod-like liquid crystal compound, and in a case where the optically anisotropic layer X is a negative A-plate, the first liquid crystal compound is a rod-like liquid crystal compound, and the second liquid crystal compound is a disk-like liquid crystal compound.

9 . The phase difference film according to claim 8 ,
wherein an in-plane retardation of the optically anisotropic layer X at a wavelength of 550 nm is 120 to 240 nm.

10 . The phase difference film according to claim 8 ,
wherein a twisted angle of the first liquid crystal compound is 80°±30°.

11 . The phase difference film according to claim 8 ,
wherein a twisted angle of the second liquid crystal compound is 175°±30°.

12 . The phase difference film according to claim 8 ,
wherein a value of a product Δnd of a refractive index anisotropy Δn of the optically anisotropic layer Y at a wavelength of 550 nm and a thickness d of the optically anisotropic layer Y is 120 to 240 nm.

13 . The phase difference film according to claim 8 ,
wherein a value of a product Δnd of a refractive index anisotropy Δn of the optically anisotropic layer Z at a wavelength of 550 nm and a thickness d of the optically anisotropic layer Z is 70 to 190 nm.

14 . A circularly polarizing plate comprising:
a polarizer; and the phase difference film according to claim 1 .

15 . A display device comprising:
the phase difference film according to claim 1 .

16 . A circularly polarizing plate comprising:
a polarizer; and the phase difference film according to claim 2 .

17 . A display device comprising:
the phase difference film according to claim 2 .

Assignees

• Fujifilm Corp

Inventors

• Takahashi Yuta
• Furuki Yusuke
• Kuwahara Hiroki

Classifications

• H10K59/8791

  Arrangements for improving contrast, e.g. preventing reflection of ambient light · CPC title

• G02B5/3016 Primary

  involving passive liquid crystal elements (optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528) · CPC title

• G09F9/00

  Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements (in which the variable information is permanently attached to a movable support G09F11/00; abacus G06C1/00; slide-rules G06G1/00) · CPC title

• H05B33/02

  Details · CPC title

• G02B5/30

  Polarising elements (light-modulating devices with active elements G02F1/00) · CPC title