Patent ID: 8859648
Filing Date: 2014-10-14
Classification: C08G,C08J,G02B

Abstract:
1. A retardation film comprising polyester having a photoelastic coefficient of 18×10 −12 Pa −1 to 27×10 −12 Pa −1 , wherein the polyester includes a structural unit expressed by the chemical formulas (I), (II), (III), or (IV) and wherein the mole fractions (%) of structural units expressed by the chemical formulas (I), (II), (III) and (IV) are denoted by l, m, n, and o, respectively, with l, m, n, and o satisfying the following equations (4) and (5): wherein formulas (I), (II), (III) and (IV) are as follows: R R R R R R R R