The relative position (M) of two members (33, 34) is sensed by scanning (S) an optical beam (25) over an encoded pattern (20) carried by one of the members, and by using a read head (21) secured to the other member to receive an optical signal transmitted from the encoded pattern (20). This optical signal...http://www.google.es/patents/US5210409?utm_source=gb-gplus-sharePatente US5210409 - Apparatus and method for sensing the relative position of two members employing a variable wavelength source and wavelength dependant scanner
Apparatus and method for sensing the relative position of two members ...
