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:
Jul. 03, 1990
Filed:
Oct. 25, 1989
Donald T Morelli, Walled Lake, MI (US);
Joseph P Heremans, Troy, MI (US);
Dale L Partin, Sterling Heights, MI (US);
Christopher M Thrush, Utica, MI (US);
Louis Green, Rochester Hills, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
For increased sensitivity, an improved position sensor includes a magnetic circuit in which the stationary portion includes a permanent magnet whose width is optimally 1.5 times the tooth pitch of the exciter portion of the sensor and the magnet face proximate the exciter includes a thin layer of ferromagnetic material over which is centered a narrow magnetic sensing element, such as a magnetoresistor. The sensing element has a width typically less than the tooth width. The sensing element includes a thin film of a monocrystalline semiconductive material, preferably having only a moderate bulk mobility and a larger band gap, such as indium arsenide. Current carriers flow along the length of the thin film in a surface accumulation layer, effective to provide a significant apparent increase in mobility and conductivity of said semiconductive material, and an actual increase in magnetic sensitivity and temperature insensitivity. The flux density is typically applied by appropriate magnet thickness or choice of magnet material without the need of a flux guide.