| 摘要 |
PROBLEM TO BE SOLVED: To provide a mold for molding an optical element reducing the amount of optical axis deviation between two optical surfaces of an optical element and the amount of deviation among the central axis of a plane regarded as an assembling base formed at the outer peripheral side of the optical element and the optical axes of the optical surfaces without reducing choices of material properties and needing wastefully high machining precision. SOLUTION: The mold is equipped with a highly expansive member 14 between a lower mold 12 and a body mold member 13, which is a ring-shaped member having notches in the direction of diameter and made of a material having a higher linear expansion coefficient than those of the lower mold 12 and the body mold member 13. The dimensions of the lower mold 12, the highly expansive member 14 and the body mold member 13 are set so that the lower mold 12 and the highly expansive member 14, and the highly expansive member 14 and the body mold member 13 are kept in a tight contact state respectively by thermal expansions of respective members caused by being heated at a temperature of molding. COPYRIGHT: (C)2008,JPO&INPIT
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