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AssigneesMatsushita Electric Industrial Co., Ltd., Sumita Optical Glass, Inc.
InventorsTadayoshi Yonemoto, Yoshiyuki Shimizu, Takashi Inoue, Toshihiko Muroi
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In manufacturing a glass material used for a re-heat press method of manufacturing high-precision optical glass components including a lens, prism or the like, a glass material can be manufactured which has no defect inside of or on the surface of the glass, and without requiring a process of grinding and polishing the glass. The glass material is manufactured by dropping melted glass from the glass outlet of a glass melting furnace to a mold and cooling the dropped glass on the mold. The distance between the mold and the glass outlet is in a range which maintains the temperature of the stretched area of dropping glass--the area where the melted glass dropped on the mold is spontaneously separated by its own weight and surface tension at its softening temperature or above. The temperature of the glass around the stretched area is at least its softening temperature, and the glass around that area is instantaneously incorporated into the glass on the mold after separation. As a result, there is no difference in temperature over the entire glass, and no defect is generated inside and on the surface of the glass.
A method of manufacturing a glass blank used for optical elements comprising the steps of:
Dependencies are inferred from the claim text.