OPTICAL WORKPIECE MEMBER, OPTICAL MEMBER, OPTICAL SYSTEM AND OPTICAL ALIGNER

摘要

PROBLEM TO BE SOLVED: To provide a material to be used for a highly precise optical system using UV light and vacuum UV light without degrading working precision or productivity even when the material is a fluoride single crystal having a sub-grain boundary in a ä111} crystal face perpendicular to the optical axis direction. SOLUTION: The optical workpiece member 1 is a fluoride single crystal transmitting rays at a wavelength of 250 nm or less and is processed to allow the face direction of the ä111} crystal face of the fluoride single crystal to be matched or almost mutched with the optical axis direction, wherein the amount of sub-grain boundaries present on the ä111} crystal face of the fluoride single crystal is≤0.1 cm/cm2. COPYRIGHT: (C)2007,JPO&INPIT