| 摘要 |
PROBLEM TO BE SOLVED: To obtain a phase difference plate film of a large area which is lightweight and excellent in mass-productivity and has the optical axis tilted from the normal line direction of the film by forming a specified dielectric material by oblique vapor deposition on a transparent polymer film. SOLUTION: At least one dielectric layer is formed on at least one surface of a transparent polymer film. The dielectric layer has positive refractive index anisotropy and the optical axis tilted by 20 to 70 deg. from the normal line direction of the film. As for the dielectric material, such a material is used that it can be formed into a thin film by vacuum vapor deposition and that when the film is formed by oblique vapor deposition, the film shows positive refractive index anisotropy with the optical axis tilted by 20 to 70 deg. from the normal line direction of the film. Metallic oxides such as Ta2 O5 , WO3 can be used. By controlling the angle of oblique vapor deposition to 50 to 85 deg., the angle between the optical axis of the dielectric layer and the normal line direction of the film can be controlled to the specified angle from 20 to 70 deg.. The inorg. dielectric material layer formed by oblique vapor deposition has 0.2 to 5μm thickness, and preferably 0.4 to 1μm thickness. |
