PLASTIC OPTICAL ELEMENT, ITS MOLDING METHOD, AND OPTICAL SCANNING UNIT

摘要

PROBLEM TO BE SOLVED: To obtain a method for molding a plastic optical element which can prevent color dislocation at low cost and secure adhesive strength. SOLUTION: In the method for molding the plastic optical element, the plastic optical elements 1 each having at least one transfer surface having a non-symmetrical shape to a light axis and at least one sink part 21 which is induced selectively to a non-transfer surface other than the transfer surface are molded simultaneously by one mold having at least two cavities. The elements are molded while the positional relationship between the direction A indicating the non-symmetrical shape of the transfer surface and the selectively induced sink part 21 is unified between the cavities. Since the direction of warpage in the element 1 can be made constant, effects such as the prevention of color dislocation caused by the difference in the warpage direction and the improvement of installation accuracy owing to the insurance of adhesive strength. COPYRIGHT: (C)2006,JPO&NCIPI