| 摘要 |
PURPOSE:To obtain a mold capable of carrying out specular abrasion without causing fusing with glass at high temperature and slightly being oxidized, by coating a molding face of a mold for forming an optical element made of glass with boron nitride of cubic system. CONSTITUTION:In a mold to be used in press molding of an optical element 4 made of glass, a thin film layer 2 of boron nitride of cubic system is formed on a molding face of a mold parent material 1 consisting of a carbide alloy to be brought into contact with the glass element 4. In order to mold the optical element 4 by using the mold, a glass material 3 laid between molds is press molded. As a method to form the thin film layer of boron nitride of cubic system on the mold parent material 1 is used CVD method or PVD method. A carbide alloy is preferably used as the mold parent material element. Other materials having a coefficient of thermal expansion close to that of the carbide alloy may be used. The mold has excellent releasability from glass and extremely low surface deterioration even with repeated use.
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