METHOD AND APPARATUS FOR PRODUCING OPTICALLY HIGH QUALITY AND LARGE SIZE OPTICAL PART FROM SYNTHETIC QUARTZ GLASS BLOCK AND OPTICAL PART MANUFACTURED BY USING IT

摘要

PROBLEM TO BE SOLVED: To produce an optically high quality and a large size optical part from a synthetic quartz glass block. SOLUTION: The quartz glass block is placed in a part mold in a furnace with protection gas atmosphere and heated by 50-170K higher than its softening point. The keeping time at the heated temperature is 20-90 minutes and the quartz glass block is pressed in the part mold during the keeping time. As a result, the quartz glass block is treated mildly obtaining a good yield per input and input energy is decreased and its perfect filling in the part mold is accomplished.