| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of an optical diffusion film which has excellent thermal resistance and mechanical strength, these being inherent in a bi-axially stretched film, and also shows excellence in light transmittance and optical diffusion. SOLUTION: In the method of manufacturing the optical diffusion film having an optical diffusion layer by bi-axially stretching an un-stretched film of a mixture of 50 to 99 pts.mass of a crystalline polyester and 1 to 50 pts.mass of a thermoplastic resin incompatible with the polyester, the un-stretched film is stretched at a stretch ratio of 2.5 or more at a stretch velocity of less than 300%/sec in vertical and lateral directions respectively. The film made by the method shows an all light transmittance of 85% or more, a haze of 50% or more, a rate of a dimensional change of not more than 3% at 150°C in both vertical and lateral directions, and tensile strength of 100 MPa or more in both vertical and lateral directions. COPYRIGHT: (C)2007,JPO&INPIT |
