PURPOSE: To precisely and easily obtain an optical glass element of intricate shape in which curved surfaces and flat surfaces are coexistent by forming the element with a couple of upper and lower dies for transferring the working surface of the element and a barrel die.
CONSTITUTION: The appearance of an upper die 1 is shown by (a), half of the transfer surface 1a is recessed and the other half is inclined and flattened, and the side face is precisely slid through a barrel die 3. Meanwhile, the die 1 is made square in conformity to the shape of the element to be formed, and the split face 8 is paralleled to the side face. The transfer surface 2a of the lower die 2 shown by (b) is recessed, the side face is precisely slid through the barrel die 3, and the die is made square in conformity to the shape of the element. A gob 4 in the amt. necessary to obtain the element having a requisite thickness is supplied to the mold consisting of the upper die 1, lower die 2 and barrel die 3, the mold is placed on the upper and lower heater blocks 5 and 6, and the gob is heated, pressed and cooled to obtain a molded article from the mold.
MURATA ATSUSHI
TANAKA YASUHIRO
SHIRAFUJI YOSHINORI
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