The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 21, 1994
Filed:
Aug. 31, 1992
Bruce A May, Poway, CA (US);
Thomas A Lasko, Coronado, CA (US);
Dwight H Everett, Encinitas, CA (US);
Science Applications International Corporation, San Diego, CA (US);
Abstract
A coherence shifting interferometry system determines the thickness or refractive index of an optically transmissive medium. The system utilizes an optical energy source for generating a source beam. The source beam is divided into two beams by reflecting one portion of the beam off of a reflective surface, e.g., a front surface, of an optically transmissive test sample having the unknown thickness or refractive index. A second portion of the beam is transmitted through the sample and reflected off a refractive interface in the sample, e.g., a back surface. The two reflected beams are combined into a composite beam. The composite beam is then directed to a Mach-Zehnder type interferometer, where a portion of the combined beam traverses a fixed optical path length, and another portion traverses a variable optical path length. The variable optical path length is adjusted to realign portions of the two beams and cause interference, and the amount of adjustment provides a measure of the unknown thickness or refractive index.