PLASTIC OPTICAL PRODUCT, PLASTIC OPTICAL FIBER, APPARATUS FOR MANUFACTURING PLASTIC OPTICAL PART, AND METHOD FOR MANUFACTURING PLASTIC OPTICAL PART AND PLASTIC OPTICAL PRODUCT

摘要

A clad tube ( 21 ) is formed by melting and extruding a polymer, such as PMMA. The molten polymer is extruded through an extrusion die ( 12 ) to form a soft clad ( 20 ). The soft clad ( 20 ) is forwarded to a molding die ( 13 ) to correct the shape of the soft clad ( 20 ). A decompression chamber ( 31 ) in the molding die ( 13 ) is decompressed so that the outer surface of the soft clad ( 20 ) is tightly in contact with forming surface ( 30 b) of the molding die ( 13 ). After molding the soft clad ( 20 ) in the molding die ( 13 ), the clad tube ( 20 ) with low fluctuation in thickness is obtained.