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Title: Optical extensometer

Abstract

An optical extensometer is described using sequentially pulsed light beams for measuring the dimensions of objects by detecting two opposite edges of the object without contacting the object. The light beams may be of different distinguishable light characteristics, such as polarization or wave length, and are time modulated in an alternating manner at a reference frequency. The light characteristics are of substantially the same total light energy and are distributed symmetrically. In the preferred embodiment two light beam segments of one characteristic are on opposite sides of a middle segment of another characteristic. As a result, when the beam segments are scanned sequentially across two opposite edges of the object, they produce a readout signal at the output of a photoelectric detector that is compared with the reference signal by a phase comparator to produce a measurement signal with a binary level transition when the light beams cross an edge. The light beams may be of different cross sectional geometries, including two superimposed and concentric circular beam cross sections of different diameter, or two rectangular cross sections which intersect with each other substantially perpendicular so only their central portions are superimposed. Alternately, a row of three light beams can bemore » used including two outer beams on opposite sides and separate from a middle beam. The three beams may all be of the same light characteristic. However it is preferable that the middle beam be of a different characteristic but of the same total energy as the two outer beams.« less

Inventors:
 [1];  [2];  [2]
  1. Kennewick, WA
  2. Richland, WA
Issue Date:
Research Org.:
Battelle Memorial Institute, Columbus, OH (United States)
OSTI Identifier:
863233
Patent Number(s):
4129384
Assignee:
Batelle Memorial Institute (Columbus, OH)
Patent Classifications (CPCs):
G - PHYSICS G01 - MEASURING G01B - MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS
DOE Contract Number:  
AC06-76RL01830
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
optical; extensometer; described; sequentially; pulsed; light; beams; measuring; dimensions; detecting; opposite; edges; contacting; distinguishable; characteristics; polarization; wave; length; time; modulated; alternating; manner; reference; frequency; substantially; total; energy; distributed; symmetrically; preferred; embodiment; beam; segments; characteristic; middle; segment; result; scanned; produce; readout; signal; output; photoelectric; detector; compared; phase; comparator; measurement; binary; level; transition; edge; sectional; geometries; including; superimposed; concentric; circular; sections; diameter; rectangular; intersect; perpendicular; central; portions; alternately; row; outer; separate; preferable; wave length; central portions; total energy; pulsed light; reference frequency; light energy; substantially perpendicular; reference signal; preferred embodiment; light beam; light beams; central portion; opposite edges; beam segment; circular beam; opposite edge; beam segments; phase comparator; optical extensometer; measurement signal; /356/

Citation Formats

Walker, Ray A, Reich, Fred R, and Russell, James T. Optical extensometer. United States: N. p., 1978. Web.
Walker, Ray A, Reich, Fred R, & Russell, James T. Optical extensometer. United States.
Walker, Ray A, Reich, Fred R, and Russell, James T. Sun . "Optical extensometer". United States. https://www.osti.gov/servlets/purl/863233.
@article{osti_863233,
title = {Optical extensometer},
author = {Walker, Ray A and Reich, Fred R and Russell, James T},
abstractNote = {An optical extensometer is described using sequentially pulsed light beams for measuring the dimensions of objects by detecting two opposite edges of the object without contacting the object. The light beams may be of different distinguishable light characteristics, such as polarization or wave length, and are time modulated in an alternating manner at a reference frequency. The light characteristics are of substantially the same total light energy and are distributed symmetrically. In the preferred embodiment two light beam segments of one characteristic are on opposite sides of a middle segment of another characteristic. As a result, when the beam segments are scanned sequentially across two opposite edges of the object, they produce a readout signal at the output of a photoelectric detector that is compared with the reference signal by a phase comparator to produce a measurement signal with a binary level transition when the light beams cross an edge. The light beams may be of different cross sectional geometries, including two superimposed and concentric circular beam cross sections of different diameter, or two rectangular cross sections which intersect with each other substantially perpendicular so only their central portions are superimposed. Alternately, a row of three light beams can be used including two outer beams on opposite sides and separate from a middle beam. The three beams may all be of the same light characteristic. However it is preferable that the middle beam be of a different characteristic but of the same total energy as the two outer beams.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1978},
month = {1}
}

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