PURPOSE: To obtain a phase-difference plate excellent in transparency and resistance to light, heat and solvent by using a specified glutarimide resin.
CONSTITUTION: This phase plate consists of a glutarimide acrylic resin consisting of 5-80mol% of a glutarimide structural unit shown by the formula and 95-20mol% of a methyl methacrylate unit. In the formula, R is hydrogen, 1-8C alkyls, 5-10C cycloalkyls or 6-10C aryls. Besides, the R in the formula is hydrogen and methyl, the intrinsic birefringence is positive, and the positive birefringence is made negative by changing the R. The Tg of the resin is lowered when the content of the structural unit is <5%, and the workability is deteriorated at >80%. The transparency, resistance to light, etc., are improved by the methyl methacrylate unit. The phase plate is formed by forming an undrawn film by extrusion molding and drawing the film.
KOIZUMI KAZUHIKO
MURAMATSU NORIYUKI
MURATA YOSHIFUMI
