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Title: Diffraction encoded position measuring apparatus

When a lightwave passes through a transmission grating, diffracted beams appear at the output or opposite side of the grating that are effectively Doppler shifted in frequency (phase) whereby a detector system can compare the phase of the zero order and higher order beams to obtain an indication of position. Multiple passes through the grating increase resolution for a given wavelength of a laser signal. The resolution can be improved further by using a smaller wavelength laser to generate the grating itself. Since the grating must only have a pitch sufficient to produce diffracted orders, inexpensive, ultraviolet wavelength lasers can be utilized and still obtain high resolution detection.
Authors:
 [1]
  1. (Thousand Oaks, CA)
Publication Date:
OSTI Identifier:
867996
Report Number(s):
US 5050993
DOE Contract Number:
AC03-86SF16499
Resource Type:
Patent
Research Org:
Rockwell International Corp
Country of Publication:
United States
Language:
English
Subject:
diffraction; encoded; position; measuring; apparatus; lightwave; passes; transmission; grating; diffracted; beams; appear; output; opposite; grating; effectively; doppler; shifted; frequency; phase; whereby; detector; compare; phase; zero; beams; obtain; indication; position; multiple; passes; grating; increase; resolution; wavelength; laser; signal; resolution; improved; wavelength; laser; generate; grating; grating; pitch; sufficient; produce; diffracted; inexpensive; ultraviolet; wavelength; lasers; utilized; obtain; resolution; detection; wavelength laser; wavelength laser; multiple passes; ultraviolet wavelength; multiple pass; measuring apparatus; doppler shift; diffracted beam; transmission grating; wavelength lasers; diffracted beams; laser signal /356/250/