An encoder includes an electrically conductive reference scale having surface steps formed at predetermined positions; an electrically conductive probe having a tip disposed opposed to the reference scale; wherein the reference scale and the probe are relatively movable in a direction...http://www.google.es/patents/US5721721?utm_source=gb-gplus-sharePatente US5721721 - Two scanning probes information recording/reproducing system with one probe to detect atomic reference location on a recording medium
Two scanning probes information recording/reproducing system with one probe ...
