| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical film which is sufficiently thin to make a liquid crystal display device small in size and thin in thickness and has optical characteristics such as appropriate retardation and excellent sticking performance to a polarizer. <P>SOLUTION: The optical film contains a cyclic olefin resin in a film thickness of 20 μm to 60 μm and satisfies expressions (1): 0≤Re≤75, (2): 20≤Rth≤255 and (3): 200≤D≤1,000, wherein Re represents a retardation value in a plane direction at a wavelength of 590 nm, Rth is a retardation value in a film thickness direction at a wavelength of 590 nm, and D represents a moisture permeability at 40°C and 90% RH. The film is manufactured by a method including: a step of dissolving a cyclic olefin resin in an organic solvent to prepare a dope; a casting step of casting the dope into a film state on a support; a peeling step of peeling the cast film from the support; a drying step of drying the peeled film; and a step of winding up the film. In a polarizing plate comprising a polarizer and two protective films disposed in both sides of the polarizer, at least one sheet of the above optical film can be used as the protective film. <P>COPYRIGHT: (C)2008,JPO&INPIT |
