SCANNING UNIT OF OPTICAL POSITION-MEASURING DEVICE, AND THE OPTICAL POSITION-MEASURING DEVICE

摘要

PROBLEM TO BE SOLVED: To form a scanning unit of an optical position measuring device so that the optical path of scanning remains, in a state of not being interfered, as much as possible.;SOLUTION: The inside space IR of the scanning unit 2, in which a light ray flux L is directed for scanning of a scale 1 in the inside space, is closed in a dustproof manner, with respect the outside space AR. The inside space IR is closed by a scanning plate 6 positioned relative to the scale 1; the light ray flux L passes through the scanning plate and the scale 1 is irradiated; the inside space IR is connected to the outside space AR via a filter 13; and while the filter is dustproof, it is gas permeable and vapor permeable.;COPYRIGHT: (C)2007,JPO&INPIT