AN APPARATUS FOR DETERMINING THE POSITION OF A MOVABLE MECHANICAL ELEMENT AND METHOD OF MARKING A MECHANICAL ELEMENT

摘要

A mechanical element comprising an optically readable marking, the optically readable marking comprising a surface having a first reflectivity and a plurality of areas having a second reflectivity, characterised in that: said areas having a second reflectivity have a width which is generally constant in a direction parallel to the direction of movement of the mechanical element.