Patent ID: 7559214

Claim:
An optical element manufacturing method, comprising: a preparation step of preparing a lower mold having a lower mold surface for forming an optical function surface of an optical element to be manufactured, an upper mold having an upper mold surface for forming another optical function surface of the optical element and an outer shape restricting surface for the optical element, said upper mold being opposed to the lower mold; a reference surface formation step of forming a positioning reference surface on a rim of the optical element by heating the outer shape restricting surface and the lower mold surface and dropping molten glass onto the lower mold surface so as to collide with the lower mold surface and spread to be in contact with the outer shape restricting surface; a pressing step of forming the two opposed optical function surfaces of the optical element by, after the formation of the reference surface, opposing the lower mold and the upper mold that is heated and bringing them relatively close to each other while the glass is still at a temperature at which it is deformable by pressing, and pressing the glass; and an element taking out step of, after the pressing step, releasing the glass from the pressing by the upper and the lower molds and taking out the molded optical element, wherein a temperature of the outer shape restricting surface in the reference surface formation step and the pressing step is higher than a temperature which is a difference when 100° C. is subtracted from a glass transition temperature (° C.) of the glass, wherein the reference surface formation step, the pressing step, and the element taking out step are performed while temperatures of the outer shape restricting surface, the lower mold surface and the upper mold surface are maintained at constant target temperatures, and wherein the constant target temperatures of the outer shape restricting surface, the lower mold surface and the upper mold surface are lower than that of the dropping molten glass.