Canon Kabushiki Kaisha

Yasunao Oyama

Kazutaka Terashima

A crystallization method includes the steps of melting a crystallized material in a crucible by heating, and growing a crystal by cooling and coagulating the melted material, wherein said melting step includes introducing a predetermined gas into the melted material.

Crystallization method and crystallization apparatus

For realizing an optical member for vacuum ultraviolet with little absorption and with a low deliquescence nature and a low cleavage nature, a halide of an alkali metal such as Li, Na, Cs, or the like and a halide of any one of alkaline earth metals and other elements such as Ca, Sr, Ba, Mg, Zn, and the like are mixed in a ratio of 1:1, the mixture is sintered, and a fluoride crystal of AMF type perovskite structure is grown. The crystal is processed to fabricate a substrate of an optical member such as a lens, a mirror, a prism, or the like for excimer lasers. Alternatively, the crystal is used as an evaporation source to coat a substrate of an optical member therewith. It is thus feasible to obtain optical members with little absorption in the vacuum ultraviolet region and with an excellent durability.

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Tokyo, Japan

Yasunao Oyama