申请人:TORAY INDUSTRIES, INC.
公开号:EP0331746A1
公开(公告)日:1989-09-13
A polyester film suited for optical recording media, which has a photo elasticity coefficient up to 1.2 x 10⁻³ mm²/kgf, a surface roughness, Rt, up to 100 nm, and an average distance between surface projections, Sm, of 20 µm or more. The film does not cause scattering or interference of light and produces no optical distortion even when heated or pressed, thus being useful as a support layer or a cover layer of optical recording media such as optical cards, optical discs, optical recording tapes, etc.
ABSTRACT
This invention relates to a polyester film suited for use in optical recording medium. The polyester film of the present invention has a modulus of photoelasticity of not more than 1.2 x 10⁻³ mm²/kgf, a maximum surface roughness Rt of not more than 100 nm and a mean interval Sm between adjacent surface projections of not less than 20 µm, so that the light scattering and interference are not caused, and optical strain is not generated even a thermal stress or an external force is exerted to the film. Thus, the polyester film of the present invention can be used as the supporting layer or the cover layer of optical recording media such as optical cards, optical disks and optical recording tapes.
一种适用于光学记录介质的聚酯薄膜,其光弹性系数高达 1.2 x 10-³ mm²/kgf ,表面粗糙度 Rt 高达 100 nm,表面凸起之间的平均距离 Sm 为 20 µm 或更大。这种薄膜不会引起光的散射或干涉,即使在加热或挤压时也不会产生光学变形,因此可用作光学记录介质(如光卡、光盘、光学记录磁带等)的支撑层或覆盖层。
摘要
本发明涉及一种适用于光学记录介质的聚酯薄膜。本发明的聚酯薄膜具有不大于 1.2 x 10-³ mm²/kgf 的光弹性模量、不大于 100 nm 的最大表面粗糙度 Rt 和不小于 20 µm 的相邻表面凸起之间的平均间隔 Sm,因此不会造成光散射和干扰,即使对薄膜施加热应力或外力也不会产生光学应变。因此,本发明的聚酯薄膜可用作光学卡、光盘和光学记录磁带等光学记录介质的支撑层或覆盖层。