Study on high accuracy optical encoder with 30 bits

This paper describes a fabrication method for a high accuracy disk which has a higher accuracy than a drawing system of an original disk pattern, and development of an optical rotary encoder with a resolution of 30 bits. High accuracy disk technology is the most significant technology regarding fine angular sensors, and it has an accuracy of less than 0.5 /spl mu/m and 1 sec as it reaches its limitation. However, concerning the disk for an angular sensor it is necessary to obtain a higher accuracy. And then, this study has enabled the creation of a higher accuracy disk and encoder by rejecting disk error which measured at repeatable errors. By using the studied technology, it was possible to make the high a resolution and high accuracy optical encoder with the resolution of 30 bits.