| 摘要 |
PROBLEM TO BE SOLVED: To maintain the smoothness of a film surface, to lessen unequal orientation and to accelerate the deorientation of molecular chains by applying specified tension on a film in the direction perpendicular to the major axis direction of the refractive index ellipse within the film plane and heat treating the film is a temp. atmosphere below the glass transition point (Tg) temp. SOLUTION: The major axis direction of the refractive index ellipse within the film plane is fixed in parallel with the fixed ends by jigs which uniformly press only a pair of both ends facing each other of the thermoplastic film. The film is then heat treated by applying specified tension thereon in the direction perpendicular to the fixed ends under the conditions under which the spacing LMD at both ends of the fixed film and the spacing LTD at both ends not subjected to the restriction by the jigs attains LMD/LTD>1.0. The major axis direction of the refractive index ellipse in the plane is, therefore, changed 90 deg.. As a result, the optical compensation film which is 5nm<=|nx -ny |×d<=80nm when the main refractive index are defined as nx , ny and the thickness is defined as d, is <=10% in the deflection width thereof and has excellent smoothness and the liquid crystal display element formed by using the same are obtd. |
