| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject mold high in hardness, good in releasability for glass, and hard to develop film debonding, thus high in durability, by forming a chromium nitride layer at least on the molding surface of a mold matrix to be used for press molding of a glass optical element followed by oxygen ion implantation into the layer to convert at least the surface to a chromium oxide layer. SOLUTION: A chromium nitride layer is formed at least on the molding surface 3 of a mold matrix 2 by e.g. ion beam sputtering technique followed by oxygen ion implantation pref. at 0.01-1Lμm in ion penetration depth and at 1×10<15> to 1×10<19> ions/cm<2> in quantity into the chromium nitride layer to convert at least the surface to a chromium oxide layer. As a result, the chromium oxide layer has such a characteristic that oxygen density is distributed gradient-fashion so as to gradually decrease from the molding surface toward the direction of depth, and there is no interface between the chromium oxide layer and the chromium nitride layer, thus affording firm adhesion therebetween.
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