| 摘要 |
PROBLEM TO BE SOLVED: To disclose an ultra-small sized interference type optical fiber encoder read head for detecting the scale grid displacement of a very fine pitch. SOLUTION: This read head comprises a source grid diffracting a diverging source light to a +/- first beam and a pair of mirrors reflecting the +/- first beam to focus on a scale grid. The +/- first scale light beam is reflected/diffracted so as to return from the scale grid to the mirror, then reflected and returns to focus on a pair of neighboring optical fiber receiver channels. An interference field forming grid arranged ahead of the receiver channel forms an interference fringe having a desired pitch. Movement of the interference fringe is detected by the optical fiber receiver channel to provide a displacement information. A read head can be constituted to allow mainly the +/- first light or only the +/- first light to reach the receiver channel. COPYRIGHT: (C)2008,JPO&INPIT
|
