| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a calcium fluoride crystal in which the transmittance through the crystal at a wavelength for use can be improved. SOLUTION: In production processes for purifying, growing and annealing the calcium fluoride crystal, the scavengers to be used as antioxidants are added such that a solid-powdered scavenger and a gas scavenger are added both at the same time or each at different times, wherein the solid-powdered scavenger comprises one of carbon, Teflon (R), and zinc fluoride, or mixtures thereof; and the gas scavenger comprises hydrogen fluoride, carbon fluoride and fluorine. COPYRIGHT: (C)2003,JPO
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