| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical device exhibiting high phase difference development using a material which is more inexpensive than polyimide and is capable of using an environmentally friendly solvent. <P>SOLUTION: The optical film includes an optical compensation layer having refractive index anisotropy of nx>ny>nz, 30-80 nm front face phase difference Re expressed by formula (1) and 120-180 nm thickness directional phase difference Rth expressed by formula (2). The optical compensation layer contains a polyvinyl alcohol based resin containing a repeating unit expressed by structural formula (I) and having degree (n) of polymerization of 1,500-5,000. Formula (1) is Re=(nx-ny)×d, formula (2) is Rth=(ny-nz)×d, wherein d:the thickness (nm) of the optical compensation layer. <P>COPYRIGHT: (C)2011,JPO&INPIT |
