| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method for molding an optical element, which permits the irregularity of the volume of a supplied optical element material and makes it possible to mold the optical element capable of being faborably built in the barrel tube with a simplified process. SOLUTION: This method for molding an optical element comprises press- molding a thermally softening optical element material, molding the optical function surface of the optical element and simultaneously controlling the outer diameter of the element. Therein, the characteristic comprises forming a radially directed projection 51 at least one portion of the outer peripheral surface 52 of the optical element material 5. It is preferable that an edge portion 103 whose outer diameter is controlled by the projection 51 is molded. It is further preferable that the relation of the following inequality is established between a diameter X at the projection 51 and the inner diameter Y of a mold for controlling the outer diameter. Y(1+Tα2)/(1+Tα1}-0.3<=X<Y (α1: the thermal expansion coefficient of the optical element material,α2: the thermal expansion coefficient of the material of the mold, T: the molding temperature of the optical element.</p> |
