| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a cellulosic phase difference film of an extremely stable display grade by suppressing the fluctuation in the phase difference value which is the drawback of the conventional cellulosic phase difference film while effectively utilizing the advantage of saponification lamination of a cellulosic protective film, a polarizing plate protective film, an elliptical polarizing plate, and a display device. <P>SOLUTION: The phase difference film includes a cellulose derivative and ranges 40 to 400 nm in the retardation value Rt in the thickness direction expressed by the following formula (1), wherein the fluctuation in the retardation value Rt (a) in the thickness direction reversible under the environment of 20 to 80% RH is ≤12 nm. The equation (1) is Rt=((nx+ny)/2-nz)xd, and the equation A is Rt(a)=¾Rt(b)-Rt(c)¾. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
