Patent ID: 7923999
Filing Date: 2011-04-12
Classification: G01R

Abstract:
1. A microelectromechanical modulating magnetic sensor comprising: a base; a magnetic transducer associated with the base that provides an output in response to a magnetic field; at least part of the magnetic transducer being positioned in a first plane; a plurality of movable flux concentrators positioned to move relative to the magnetic transducer; the plurality of movable flux concentrators having a region of maximum concentration of flux at a predetermined region associated with the positions of the plurality of movable flux concentrators; the plurality of movable flux concentrators being substantially located in a second plane and oscillating substantially within the second plane; the second plane being substantially parallel to the first plane; at least one flux collector positioned to collect flux for transfer onto at least one movable flux concentrator; at least part of the at least one flux collector being located substantially in the first plane such that the at least one flux concentrator overlaps at least one of the plurality of movable flux concentrators to enable continuous flux transfer during the movement of the plurality of movable flux concentrators from the at least one flux collector onto a first of the plurality of moveable flux concentrators; and, during movement of the movable flux concentrators, flux is transferred from the first of the plurality of movable flux concentrators to a second of the plurality of movable flux concentrators; the first and second movable flux concentrators being positioned a fixed distance apart such that a region of maximum concentration of flux forms therebetween; the first and second movable flux concentrators moving in tandem from a first position in which one of the first and second movable flux concentrators shields the magnetic transducer from the flux which flows between the first and second movable flux concentrators to a second position in which the magnetic transducer is adjacent the region of maximum concentration of flux; support structure for enabling the at least one movable flux concentrators to move; a power source for causing the movable flux concentrators to move at a frequency within the predetermined frequency range; whereby as the plurality of movable flux concentrators move from a first position to a second position the region of maximum concentration of flux moves relative to the transducer from a first position in which the magnetic transducer is not exposed to flux flowing between the first and second movable flux concentrators to a second position in which the magnetic transducer is exposed to flux flowing between the first and second movable flux concentrators to thereby modulate the output from the magnetic transducer.