Optical glass element molding method
AssigneeKonica Minolta Opto, Inc.
InventorsShunichi Hayamizu, Tadafumi Sakata, Tadashi Sugiyama
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Abstract
A preform is supplied between a pair of molding dies, followed by heating, softening and pressing. A smallest radius of curvature in the preform is smaller than a radius of a globular member having a volume equal to that of the preform. In this fabricating method, -an abutment portion between the molding die and the preform is located at a curved surface or the center of the molding die, thereby preventing any local abutment of the preform against the molding die.
Claims14
A method for fabricating an optical glass element having at least one optical convex surface of a small radius of curvature by pressing a preform between a pair of molding dies, said method using the preform having a smallest radius of curvature which is smaller than a radius of a globular member having a volume equal to that of the preform.
A method for fabricating an glass objective lens a numerical aperture of which is 0.65 or more for optical pickup apparatus, said method comprising the step of press-molding a preform by a pair of dies, wherein
- said method using the preform having a smallest radius of curvature which is smaller than a radius of a globular member having a volume equal to that of the preform.
Dependencies are inferred from the claim text.