MANUFACTURING METHOD OF EXTRUDED RESIN PLATE FOR OPTICAL MEMBER

PROBLEM TO BE SOLVED: To provide a manufacturing method of an extruded resin plate for an optical member further lowered in retardation in the thickness direction. SOLUTION: The manufacturing method of the extruded resin plate for the optical member is provided by which thermoplastic resin is extruded from a die in a heated and molten state, sandwiched between first and second cooling rolls, wound around the second cooling roll, then sequentially wound around one or more pieces of rear stage cooling rolls to be cooled, further cooled for solidifying keeping it flat, and taken off by a pair of take-off rolls, to manufacture the extruded resin plate for the optical member. An average circumferential speed of the rear stage cooling rolls is 0.94-1.03 times of an average circumferential speed of the first and second cooling rolls, an average circumferential speed of the pair of the take-off rolls is 0.95-1.03 times of the average circumferential speed of the rear stage cooling rolls, and the average circumferential speed of the pair of the take-off rolls is not lower than 0.91 times and lower than 0.95 times of the average circumferential speed of the first and second cooling rolls. COPYRIGHT: (C)2009,JPO&INPIT