申请人:——
公开号:US20040242823A1
公开(公告)日:2004-12-02
An optical film is provided, which displays a positive wavelength dependency across the entire wavelength region from 400 to 800 nm, and is capable of imparting a specified retardation to transmitted light with a single sheet of film. The optical film particularly, includes a thermoplastic norbornene-based resin with a specified structure formed of a structural unit (I) which imparts a positive birefringence and a structural unit (II) which imparts a negative birefringence, and which satisfies particular conditions with respect to &Dgr;N
I
(&lgr;), &Dgr;N
II
(&lgr;), &Dgr;N
I
(800) and &Dgr;N
II
(800) wherein &Dgr;N
I
(&lgr;) and &Dgr;N
II
(&lgr;) represent the difference between a refractive index Nx(&lgr;) in an x axis direction at a wavelength &lgr;, and a refractive index Ny(s) in a y axis direction, and &Dgr;N
I
(800) and &Dgr;N
II
(800) represent the difference in refractive indexes at a wavelength of 800 nm, and the x axis represents the stretching direction and the y axis represents the in-plane direction perpendicular to the x direction.
提供了一种光学薄膜,其在整个波长范围从400到800纳米内显示正波长依赖性,并能够通过单张薄膜赋予传输光以指定的延迟。该光学薄膜特别包括一种热塑性诺本烯基树脂,其具有特定的结构,由赋予正双折射的结构单元(I)和赋予负双折射的结构单元(II)组成,并满足与&Dgr;NI(&lgr;)、&Dgr;NII(&lgr;)、&Dgr;NI(800)和&Dgr;NII(800)相关的特定条件,其中&Dgr;NI(&lgr;)和&Dgr;NII(&lgr;)表示在波长&lgr;处x轴方向上的折射率Nx(&lgr;)与y轴方向上的折射率Ny(s)之间的差异,而&Dgr;NI(800)和&Dgr;NII(800)表示在波长为800纳米时的折射率差异,其中x轴代表拉伸方向,y轴代表垂直于x方向的平面方向。