Method of making an optical element mold with a hard carbon film
AssigneeCanon Kabushiki Kaisha
InventorsKiyoshi Yamamoto, Keiji Hirabayashi, Noriko Kurihara, Yasushi Taniguchi, Keiko Ikoma
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Abstract
This specification discloses a mold for use for press-molding an optical element, characterized in that at least the molding surface of a mold base material is coated with an a-C:H film containing 5-40 atom % of hydrogen therein and having a film density of 1.5 g/cm.sup.3 or more, and with hard carbon film containing 0-5 atom % of hydrogen therein and having a spin density of 1.times.10.sup.18 spin/cm.sup.3 or less and a film density of 1.5 g/cm.sup.3 or more.
Claims1
A method of manufacturing a mold for molding an optical element by heating and pressing glass material, said method comprising the steps of:
- coating an amorphous carbon hydride film on at least a molding surface of a base material of the mold, said film containing hydrogen in the range of 5 to 40 atom percent, and having a film density of at least 1.5 g/cm.sup.3 ;
- heat treating said mold base material coated with said amorphous carbon film at a temperature of 400.degree. to 750.degree. C. in an atmosphere of a partial pressure of oxygen less than 1.times.10.sup.-1 Torr;
- forming by said heat treatment, a hard carbon film comprising 0 to 5 atoms percent of hydrogen, having a spin density of less than 1.times.10.sup.18 spin/cm.sup.3 and a film density of at least 1.5 g/cm.sup.3, said hard carbon film being coated on said molding surface of said mold.
Dependencies are inferred from the claim text.