A REVOLVING RETRO-REFLECTIVE MARKER FOR AN OPTICAL TACHOMETER

Abstract

A new tachometric marker with a surface consisting of right-angle V grooves has been made by the silicon micromachining technique. Anisotropic etching on a (001) silicon surface by three conventional recipes has been adopted. The results of the etched qualities are compared; hydrazine hydrate and potassium hydroxide-isopropanol-water solutions can give good quality right-angle V grooves. The revolving retro-reflection effect associated with this marker is described. When placed on a rotating plane, it can be utilized for wide-angle and remote tachometric measurements, where proximity measurements are either impossible or dangerous.