| 摘要 |
PROBLEM TO BE SOLVED: To form an optical element in stabilized forming accuracy while decreasing the exchange frequency of a positioning jig for coaxially positioning the upper and lower molds. SOLUTION: An optical element is formed by heating a glass raw material 14 and pressing with a pair of heated upper and lower molds 1, 2. The forming part 27 for the element is constructed of the upper and lower molds 1, 2 and a positioning jig 3 for positioning the upper and lower molds 1, 2 by fitting the molds to the jig. The positioning jig 3 is divided into the inside inner circumference member 4 and the outside outer circumference member 5. Even if the outer circumference member 5 is excessively heated with the heaters 8, 9, the inner circumference member 4 is not heated to an excessively high temperature because the inner circumference member 4 is heated by the thermal conduction from the outer circumference member 5 and, accordingly, the exchange frequency of the inner circumference member 4 can be decreased. Furthermore, since the upper and lower molds 1, 2 are surely positioned, the optical element can be formed in stable forming accuracy.
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