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:
Dec. 31, 1990
Filed:
Jan. 11, 1990
Frank Bucholtz, Crofton, MD (US);
Kee P Koo, Alexandria, VA (US);
Anthony Dandridge, Alexandria, VA (US);
Alan B Tveten, Fort Washington, MD (US);
United States of America, Washington, DC (US);
Abstract
Improved passive and laser-conditioned magnetic field sensor of compact and integrated construction for enabling the detection of a magnetic field as well as an improved method of manufacture for assembling and selectively pretensioning a subassembly in order to provide an enhanced formation of the subassembly prior to use. The sensor is generally made up of a magnetic field sensing device, first and second fiber-optic elements, first and second couplers, a laser source and a combined detector and analysis means. The first and second couplers interconnect the first and second fiber-optic elements. The magnetic field sensing device is advantageously connected to one of the fiber-optic elements and is generally made up of a magneto-strictive material (MSM) of ribbon-like shape, a nonmagnetic substrate and a sensing element of optic fiber construction. This element is of predetermined and selective multistrand design between its ends and of generally serpentine shape. The sensing device is advantageously formed such that the MSM and the sensing element are uniformly and selectively pretensioned. As the result of this pretensioning, the MSM elongates when a magnetic field is detected thereby decreasing the elongation of the sensing element. Despite this decrease, the sensing element remains tensioned because of sufficient pretensioning and the phase shift in the laser as it is conducted through the optic fiber is detectable by the combined means.