Apparatus for detecting the direction of a magnetic field to sense the position of, for example, a rotary element or the like

Apparatus for detecting the direction of a magnetic field comprising in combination:

• a magnetoresistive element having an insulating substrate, first and second ferromagnetic metal film strips on said substrate for providing first and second main current conducting paths respectively perpendicular to each other, first ends of said strips being electrically connected together to define a junction, current supply terminals connected to the opposite ends of said strips and an output terminal connected to said junction between said strips for supplying an output signal;
• and
• a stationary bias magnet for supplying a bias field to said magnetoresistive element at a predetermined angle relative to one of said current conducting paths, said bias magnet being located adjacent to said element,
• and wherein the magnetic field whose direction is detected is produced by a rotary magnet mounted on and rotated with a rotating shaft, said rotary magnet supplying a magnetic flux to said magnetoresistive element responsive to the angular position of said rotating shaft wherein the output signal from said magnetoresistive element is a function of the resultant vector between the magnetic fluxes of said stationary bias magnet and said rotary magnet.

Apparatus for detecting the direction of an applied rotary magnetic field comprising:

• a magnetoresistive element disposed on an insulating substrate, said element comprising a first set of ferromagnetic strips disposed in serpentine configuration on said substrate for conducting current along substantially a first course, a second set of ferromagnetic strips disposed in serpentine configuration on said substrate for conducting current along substantially a second course perpendicular to said first course, said at first set of ferromagnetic strips being connected in series with said second set of ferromagnetic strips to define a junction therebetween from which an output signal is derived;
• a bias magnet for supplying a bias field to said magnetoresistive element in parallel with said substrate and at a predetermined angle with respect to said first current conducting course;
• and
• a signal supply magnet for supplying said applied magnetic field to said magnetoresistive element in parallel with said substrate and at an angle .theta. with respect to one of said current conducting courses, wherein .theta. varies from 0.degree. to 360.degree., the composite field produced by said bias and signal supply magnets having sufficient strength to saturate said ferromagnetic strips and having a direction to cause said output signal to vary as a function of .theta..

Apparatus for detecting the direction of an applied magnetic field comprising:

• a magnetoresistive element disposed on an insulating substrate, said element comprising at least one ferromagnetic strip on said substrate for conducting current along substantially a first course, at least a second ferromagnetic strip on said substrate for conducting current along substantially a second course perpendicular to said first course, said at least one ferromagnetic strip being connected in series with said at least a second ferromagnetic strip to define a junction therebetween from which an output signal is derived;
• a bias magnet for supplying a bias field to said magnetoresistive element in parallel with said substrate and at a predetermined angle with respect to said first current conducting course;
• said bias magnet being formed of contiguous north and south pole faces substantially parallel to said substrate;
• and
• a signal supply magnet for supplying said applied magnetic field to said magnetoresistive element in parallel with said substrate, the composite field produced by said bias and signal supply magnets having sufficient strength to saturate said ferromagnetic strips and having a direction, whereby said output signal is a function of said direction.

Apparatus for detecting the direction of an applied magnetic field comprising:

• a magnetoresistive element disposed on an insulating substrate, said element comprising at least one ferromagnetic strip on said substrate for conducting current along substantially a first course, at least a second ferromagnetic strip on said substrate for conducting current along substantially a second course perpendicular to said first course, said at least one ferromagnetic strip being connected in series with said at least a second ferromagnetic strip to define a junction therebetween from which an output signal is derived;
• a bias magnet for supplying a bias field to said magnetoresistive element in parallel with said substrate and at a predetermined angle with respect to said first current conducting course;
• and
• a signal supply magnet for supplying said applied magnetic field to said magnetoresistive element in parallel with said substrate, said signal supply magnet being comprised of contiguous north and south pole faces substantially parallel to said substrate and rotatable with respect to said magnetoresistive element, the composite field produced by said bias and signal supply magnets having sufficient strength to saturate said ferromagnetic strips and having a direction, whereby said output signal is a function of said direction.

Apparatus for detecting the position of a rotary member, comprising:

• a bias magnet for supplying a bias field, said bias magnet forming at least a portion of a disc and having contiguous, alternating polarity pole faces in a first plane to produce said bias field transversely of the respective boundaries defined by said contiguous pole faces;
• plural magnetoresistive elements, each disposed on an insulating substrate and comprising first and second ferromagnetic film strips on said substrate for providing first and second main current conducting paths respectively perpendicular to each other, said strips being connected in series to define a junction therebetween from which an output signal is derived and having current supply terminals, said plural magnetoresistive elements being positioned adjacent at least some of said boundaries defined by said contiguous pole faces whereat the insulating substrates are substantially parallel to said first plane and said elements are disposed at an angle to said respective boundaries so that said bias field is parallel to said respective substrates and at a predetermined angle with respect to one of said current conducting paths;
• and
• a rotary member adjacent said plural magnetoresistive elements and comprised of a supply magnet having at least two contiguous opposite polarity pole faces in a second plane parallel to said first plane to produce a signal field transversely of said pole faces, said supply magnet being rotatable so that said signal field rotates with respect to said magnetoresistive elements;
• said bias and supply fields producing a composite field having a rotating component, whereby said output signal is a function of said rotating component.