FOREWORD 
This paper has been prepared by the Link Division, General Precision, Inc., 
Binghamton, New York, U.S. A, to acquaint industry and science with the 
ultra-precise measuring equipment which Link is developing. 
Approximately six years ago, Link Division of General Precision, began 
work on the Link FRINGECOUNT* Micrometer. The Link FRINGECOUNT 
system uses the interference patterns derived from a Krypton light as the 
basis of its metering system; thus utilizing the wave length of light as an 
absolute measuring unit, This device makes possible absolute measure- 
ments to plus or minus one microinch or less over a two inch distance. 
There are no man-made linear scales accurate to one microinch. Link 
has produced this equipment for some time and the units are commercially 
available. 
As a result of activity in this area, Link was recently awarded a U.S. Air 
Force contract to develop an automated interferometer with an eight inch 
(200 mm. ) path length to automatically read out the x and y coordinates of 
ballistic camera film, The Automated High Accuracy Comparator is cur- 
rently under development at the Binghamton Laboratory. It will, for ex- 
ample, determine the coordinates of a satellite track against a fixed star 
background, The machine will be completely automatic once it is set up 
and will have an accuracy of between . 1 and . 5 microns, reading out directly 
in microns, microinches, or wavelengths in punch cards and paper tape. 
Plates up to 308 mm. x 308 mm. will be accepted and it will determine the 
coordinates of any desired number of images within an area of 200 mm. x 
200 mm. 
*Trademark, Link Division, General Precision, Inc. 
8/29/60