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:
Sep. 21, 1999
Filed:
Apr. 07, 1997
Luan Le, Caen, FR;
Eric Desbonnets, Caen, FR;
U.S. Philips Corporation, New York, NY (US);
Abstract
The invention relates to a system for reading magnetic information, comprising at least one read head H0 provided with two magnetoresistive rods (MR10, MR20) whose electrical resistivities (RMR10, RMR20) vary in mutually opposite senses when they are subjected to a same variation in magnetic field. According to the invention, the reading system comprises a detection module DET which comprises two resistors R of substantially the same resistance value, an amplifier A having one input and one output, and a comparator Cp having two inputs and one output. Each resistor R has a terminal connected to the output terminal (M10, M20) of one of the magnetoresistive rods, while the other terminals of the resistors are interconnected so as to form a common junction point NC. The voltage of the common junction point NC is amplified and compared with a reference voltage Vref by the comparator Cp. The output of the comparator Cp signals an accidental contact between the read head and a foreign body or asperity which may be present on the surface on which the information is stored.