High resolution absolute coder with movable coding carrier - uses scanning beam deflectable in coding carrier movement direction

摘要

The movable coding carrier carries codes read-out by a scanning beam of an optical read-out device, with the code characterising the position of the carrier. The scanning beam (2) can be deflected in the movement direction of the coding carrier (6), and follows in a preset small region the movement of the code (7) just picked up by the scanning beam. The instantaneous position of the code carrier is determined from the position information and the deflection of the scanning beam. On attaining a region boundary, the scanning beam is possibly adjusted in its search to the adjacent picked up code. Pref. the sequential codes each characterise a position of a point of the individual codes. USE/ADVANTAGE - Spacecraft rotary mechanisms, without variations of fine steps, drift of absolute precision in economical design.