DOUBLE REFRACTION OPTICAL FILM, AN OVAL POLARIZER USING THE DOUBLE REFRACTION OPTICAL FILM, AND A LIQUID CRYSTAL DISPLAY DEVICE USING THE DOUBLE REFRACTION OPTICAL FILM AND THE OVAL POLARIZER, PARTICULARLY CONCERNED WITH CONTAINING MORE THAN TWO KINDS OF POLYMER MATERIALS

摘要

PURPOSE: A double refraction optical film, an oval polarizer using the double refraction optical film, and an LCD device using the optical film and the oval polarizer are provided to realize high orientation while comprising small photoelastic coefficients which can reduce non-uniformity of contrast in a durability test, consequently a desired phase difference value can be easily obtained. CONSTITUTION: A polymer material having plus photoelastic coefficients and a polymer material having minus photoelastic coefficients are obtained together. If the polymer materials contained in a double refraction optical film satisfy a mathematical formula 1, the double refraction optical film can have small photoelastic coefficients overall. If at least one kind of other polymer material is contained, a high orientation can be realized in the overall film.