Optical device for measuring positions has a transparent scale with a measurable scale division to be scanned by a source of light and photodetectors

摘要

A transparent scale (1) made from electrically non-conductive material carries an optically scannable measuring scale division (5) scanned by a device (2) with a source (6) of light and photodetectors (8). A transparent electrically conductive layer (11) fits in front of photodetectors to shield them from electromagnetic noise fields.