| 摘要 |
The present invention relates to a retardation film using polyester having a photoelastic coefficient of -40x10-12 Pa-1 to 40x10-12 Pa-1. The present invention also relates to a polyester resin for optical use which contains a phosphorus compound, and an alicyclic component and a fluorene derivative component as constituents, and satisfies the following equations (6) and (7): <?in-line-formulae description="In-line Formulae" end="lead"?>100° C.<=glass transition temperature<=150° C. (6)<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>and<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>1.0<=(Ma/2+Mb+Mc)/P<=5.0 (7),<?in-line-formulae description="In-line Formulae" end="tail"?> wherein Ma is the number of moles of an alkali metal element contained in 1 ton of the polyester resin, Mb is the number of moles of an alkaline earth metal element contained in 1 ton of the polyester resin, Mc is the sum of the number of moles of a zinc element (Zn), a cobalt element (Co) and a manganese element (Mn) contained in 1 ton of the polyester resin, and P is the number of moles of a phosphorus element contained in 1 ton of the polyester resin.
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