Reflective polarizing film, and optical member for liquid crystal display device, and liquid crystal display device formed from same

摘要

A multilayered reflective polarizing film is provided that has high polarization performance comparable to that of an absorption-type polarizing plate, and is preferred as a polarizing plate attached to a liquid crystal cell. An optical member for liquid crystal display devices, and a liquid crystal display device formed from such a multilayered reflective polarizing film are also provided. Specifically, the reflective polarizing film includes a uniaxially stretched multilayered film in which a specific aromatic polyester containing (alkylenedioxy)di-2-naphthoic acid as a part of dicarboxylic acid components is used as a first layer, and an optically isotropic polyester having an average refractive index of 1.50 to 1.60 is used as a second layer, and that has a predetermined refractive index difference between the layers. The reflective polarizing film has an angle of orientation of 2 degrees or less.

主权项

1. A reflective polarizing film that comprises a uniaxially stretched multilayered film as a laminate of at least 251 alternately laminated first layers and second layers, wherein:
1) the first layers of the uniaxially stretched multilayered film are formed of a polyester containing dicarboxylic acid components and a diol component,
(i) the dicarboxylic acid components containing 5 mol % to 50 mol % of a component represented by the following formula (A), and 50 mol % to 95 mol % of a component represented by the following formula (B), wherein RA represents an alkylene group of 2 to 4 carbon atoms, wherein RB represents a naphthalenediyl group,
(ii) the diol component containing 90 mol % to 100 mol % of a component represented by the following formula (C),
H—O—RC—O—H  Formula C wherein RC represents an alkylene group of 2 to 4 carbon atoms,
2) the second layers of the uniaxially stretched multilayered film are formed of an optically isotropic polyester having an average refractive index of 1.50 to 1.60,3) the refractive index difference between the first layers and the second layers is 0.10 to 0.45 in a uniaxial stretch direction (X direction) within a film plane, and is 0.05 or less in a direction (Y direction) orthogonal to the uniaxial stretch direction, and in a film thickness direction (Z direction), and4) the reflective polarizing film has an angle of orientation of 2 degrees or less, wherein said angle of orientation represents the tilt of the in-plane principal orientation axis with respect to the width direction of the film.