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:
Feb. 20, 1979
Filed:
May. 05, 1977
Thomas C Cetas, Tucson, AZ (US);
University of Arizona, Washington, DC (US);
The United States of American as represented by the U.S. Government, Washington, DC (US);
Abstract
This invention relates to the use of a birefringent crystal as the sensing element in a probe thermometer constructed of certain basic optical components utilized in three separate modes. Thus, all of the modes of the invention are directed to a probe thermometer which uses the temperature dependence of the birefringence of certain single crystals as the temperature sensitive parameter. One such crystal is a Y-cut single crystal of LiTaO.sub.3. Alternative crystals having adequate sensitivity in the desired temperature range may be constructed from LiNbO.sub.3 or BaTiO.sub.3. Polarized light propagates through the crystal in two modes, the ordinary ray and the extraordinary ray, which have indices of refraction n.sup.o and n.sup.e. For LiTaO.sub.3 at room temperature, n = 2.2, B = n.sup.e - n.sup.o = 0.004, and dB/dT = 4.4 .times. 10.sup.-5 /.degree. C. The intensity of light passed through a sandwich of aligned sheet polarizer, crystal, and optical analyzer is a function of B and hence also is temperature dependent. A thermometer probe is constructed by bonding this sandwich to a bundle of optical fibers along with a dielectric mirror so that the sensor will be at the probe tip. The probe has been constructed for use in the presence of intense electromagnetic fields and also designed to eliminate the possible hazard of an electrical leakage back to the subject.