To provide a forming die which can stably form a glass lens at least one of the optical functional surfaces of which is concave in a high yield with precision pressing of glass, and its manufacturing method, as well as a method for forming the glass lens.
The forming face of the forming die is provided with a convex curve section for forming the concave surface of the glass lens, a flat surface section which is formed from the convex curve section to the outside continuously around the convex curve section and which is almost orthogonal to the central axis, and a boundary curve section which is formed in the boundary section between the convex curve section and the flat surface section so that the convex curve section turns into the flat surface section through a continuously and smoothly changing curve section. The forming die is manufactured with a rough processing process and a finish grinding process. In the finish grinding process, the roughly processed material is rotated while a fast-rotating grinding stone for finish grinding is brought into contact with the finish surface of the material and moved from the central axis to the outside so that the stone may draw a predetermined trajectory. The forming die is used as a body die, an upper die or a lower die in order to form the glass lens.
TAKIGUCHI TAKEO
SUGAWARA KISHIO
TAKAHARA HIROAKI
Toru Yui
Hitoshi Kiyono
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