Patent ID: 7242188
Filing Date: 2007-07-10
Classification: G01R

Abstract:
1. An array of integrated gradiometers, comprising: an array of cells, wherein each cell comprises: a semiconducting substrate; a first sensor, fabricated on the semiconducting substrate and responsive to the presence of the magnetic field, for producing a first electrical signal proportional to a first magnetic field strength of the magnetic field; a second sensor, fabricated on the semiconducting substrate and responsive to the presence of the magnetic field, for producing a second electrical signal proportional to a second magnetic field strength of the magnetic field; said first and second sensors being spaced apart at a distance effective for measuring a magnetic field gradient having a spatial scale of up to about 10 μm; a comparator, for receiving and comparing said first and second electrical signals, and for producing an output representing a magnitude of the magnetic field gradient applied across said sensors; a first conductor for transmitting current bias to the cell; a second conductor for transmitting a sensed voltage from the cell to a sense amplifier; and an isolation element for electrically isolated the cell from the bias and signal wires and from other cells in the array.