| 摘要 |
PROBLEM TO BE SOLVED: To prevent mutual fusion of a glass preform and a mold, and the generation of cracks or breakes in a glass optical element and haze on the surface of the glass optical element when glass preforms of fluorophosphate-based, phosphate-based, boro-phosphate-based and borate-based glass are continuously subjected to precision press molding or glass optical elements are manufactured by continuous precise press molding such that the number of shots is more than 10,000. SOLUTION: The glass preform for press molding is manufactured by a method wherein, after subjecting a preformed glass blank to heat treatment in a dry atmosphere substantially free of hydrogen, a carbon-containing film is formed on the surface of the glass blank. COPYRIGHT: (C)2005,JPO&NCIPI
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