| 摘要 |
PURPOSE:To provide the manufacture of the phase difference plate formed of a polysulfone film which has a uniform retardation value Re over the entire surface and also has superior visual angle characteristics. CONSTITUTION:Both lateral end parts of the polysulfone film (uniaxially drawn film 1) which is drawn laterally and uniaxially are shaped while its lengthwise size is maintained to form corrugate slack parts 10 and after the slack parts 10 are gripped by gripping means 2 equipped with film gripping stylet while the corrugate shape is held, a thermal shrinkage process is carried out to control the longitudinal length of the uniaxially drawn film 1 to more than 1/a'<1/2> times as long as the length before the heat shrinkage (where a' is a logical drawing rate in consideration of shearing at the time of the lateral uniaxial drawing process). The obtained film has the uniform retardation value Re, based upon an angle of incidence, over the entire surface since the refractive index in the drawing right-angled direction approximates the refractive index in the thickness direction, so its visual angle characteristics are improved. |
