Magnetoresistance effect element sensor and an electronic circuit therefor
First Claim
1. A magnetic sensor, comprising:
- a magnet having a magnetic pole surface, said surface having a center and facing an object to be detected;
a magnetoresistance effect element comprising a plurality of stripes, each stripe comprising a ferromagnetic thin film which is parallel to, and spaced apart from, said magnet surface and extends in a first direction, said plurality of said ferromagnetic thin film stripes being arranged in four groups, each group comprising a respective plurality of said ferromagnetic thin film stripes extending in the first direction and connected in series at corresponding terminals through respective ends thereof and said four groups being connected through said corresponding terminals so as to form a bridge circuit;
a plurality of second stripes disposed on each of said ferromagnetic thin film stripes, each of said second stripes comprising a conductor thin film and extending in a direction at an angle of approximately 45°
relatively to the first direction in which said ferromagnetic thin film stripes extend; and
said magnetoresistance effect element being disposed so as to deviate from the center of said magnet surface in the first direction, the first direction being perpendicular to a second direction in which said object moves relatively to the magnetic pole surface of the magnet.
1 Assignment
0 Petitions
Accused Products
Abstract
A magnetic sensor including a magnetoresistance effect element directed to prevent deterioration in the detection sensitivity occurring due to inversion of the magnetization of a plurality of ferromagnetic thin film stripes forming the magnetoresistance effect element with respect to the initial direction during the repeated operations, the magnetic sensor being arranged in such a manner that the magnetoresistance effect element is disposed at a position deviating from the center of the magnetic pole surface of a cylindrical magnet, preferably at a position deviating in a direction perpendicular to a direction in which the magnetic object to be detected is moved. The thus-employed arrangement enables a bias magnetic field to be applied to the magnetoresistance effect element in parallel to the deviation direction. Therefore, the magnetization of all of the plurality of the ferromagnetic thin film stripes forming the magnetoresistance effect element can be caused to face the same direction. As a result, the detection sensitivity can be stabilized because inversion of the magnetization can be prevented even if external magnetic fields are repeatedly applied.
58 Citations
16 Claims
-
1. A magnetic sensor, comprising:
-
a magnet having a magnetic pole surface, said surface having a center and facing an object to be detected; a magnetoresistance effect element comprising a plurality of stripes, each stripe comprising a ferromagnetic thin film which is parallel to, and spaced apart from, said magnet surface and extends in a first direction, said plurality of said ferromagnetic thin film stripes being arranged in four groups, each group comprising a respective plurality of said ferromagnetic thin film stripes extending in the first direction and connected in series at corresponding terminals through respective ends thereof and said four groups being connected through said corresponding terminals so as to form a bridge circuit; a plurality of second stripes disposed on each of said ferromagnetic thin film stripes, each of said second stripes comprising a conductor thin film and extending in a direction at an angle of approximately 45°
relatively to the first direction in which said ferromagnetic thin film stripes extend; andsaid magnetoresistance effect element being disposed so as to deviate from the center of said magnet surface in the first direction, the first direction being perpendicular to a second direction in which said object moves relatively to the magnetic pole surface of the magnet. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. A magnetic sensor for detecting an object made of a soft magnetic material, comprising:
-
a magnet having a magnetic pole surface, said surface having a center and facing an object; a magnetoresistance effect element including four groups, each group comprising a plurality of ferromagnetic thin film stripes extending in a first direction, perpendicular to a second direction of movement of the object and in parallel with respect to said magnet surface with a space therebetween and, further, extending in parallel, spaced relationship with respect to the ferromagnetic thin film stripes of each other group, said plurality of stripes in each group being connected in series through respective ends thereof and said four groups being connected so as to form a bridge circuit through terminals of respective serially connected said stripes thereof, said four groups being respectively disposed at four positions which deviate from the center of said magnet surface along said magnet surface symmetrically with respect to the center of said magnet surface; and a plurality of second stripes, each second stripe being made of a conductor thin film and formed on a respective one of said ferromagnetic thin film stripes, said second stripes extending in a direction at an angle of approximately 45°
with respect to the first direction in which said respective ferromagnetic thin film stripes extend. - View Dependent Claims (14, 15, 16)
-
Specification