RETARDATION FILM, POLARIZING PLATE, VERTICALLY-ORIENTED LIQUID CRYSTAL DISPLAY DEVICE, AND MANUFACTURING METHOD FOR RETARDATION FILM

摘要

PROBLEM TO BE SOLVED: To provide a retardation film which allows for increasing an amount of nitrogen-containing heterocyclic compound to be added and suppresses variation of retardation caused by moisture absorption.SOLUTION: A retardation film used as an optical film 13 of a polarizing plate 5 or an optical film 15 of a polarizing plate 6 contains cellulose ester and a nitrogen-containing heterocyclic compound, and exhibits a humidity expansion coefficient of 0.1-1.0% when ambient humidity changes from 5%RH to 90%RH. The cellulose ester satisfies 2.0≤X+Y≤2.9 and 0.1≤Y≤0.8 regarding the substitution degree, where X represents a substitution degree of acetyl group and Y represents a substitution degree of butyryl group.SELECTED DRAWING: Figure 1