OPTICAL FILM

摘要

A novel optical film capable of readily vitrifying the tendency and state of liquid crystal alignment, excellent in the ability to retain the alignment state, and suitable for the application to optical elements. The film is produced from a liquid-crystal material containing as the essential ingredient a liquid-crystal polyester having structural units (A) and (B) as the essential unit, exhibiting a vitrified state at a temperature lower than the liquid-crystal transition point, and having a logarithmic viscosity number ( eta ) of 0.04-0.4 dl/g as measured at 30 DEG C in a phenol/tetrachloroethane solvent (60/40 by weight), wherein each X represents independently O or C=O; each Y represents independently a group selected from among F, Cl, Br and 1-4C alkyls; and n is 0 or 1.