EP0484859A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
System for sensing changes in a magnetic field, and fabrication method
Assignee: Raytheon Co
•
Filing: 1991-11-04
•
Granted: —
•
Expires: 2011-11-04
Abstract
Abstract All of the resistors in a magnetic field sensitive circuit, both magnetoresistors (MRs)and fixed resistors (FRs), are formed simultaneously in a common fabrication process from a common magnetoresistive material. An additional structure in the form of Hall shorting strips is applied to selected resistors to rendered them MRs, while the resistors without the additional structure function as FRs. In one circuit the resistors are arranged in pairs in two voltage divider circuits. The high voltage resistor from one circuit and the low voltage resistor from the other circuit are MRs while the remaining resistors are FRs, producing an increased magnetic sensitivity. In another circuit all resistors are MRs and are positioned so that the magnetic field at one pair swings in a direction opposite to that of the other pair, further increasing the magnetic sensitivity. Discrepancies stemming from temperature coefficient mismatch and manufacturing variations are substantially reduced.
Inventors
- 👤 Robert E. Eck
- 👤 John L. Vampola
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 19:24
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/02; G01R33/06; G01R33/09
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
86 words
A system for sensing changes in a magnetic field, comprising: a plurality of resistor elements each formed from the same type of magnetoresistor (MR) material, at least one of said resistor elements including an additional structure which substantially increases its magnetoresistance compared to a resistor element of said MR material without said additional structure, and output means interconnected with said resistor elements to produce an output which varies in accordance with changes in the magnetic field strength at said resistor elements which include said additional structure.
Claim 2
Dependent Claim
44 words
The system of claim 1, said resistor elements being arranged in a pair of voltage divider circuits of two resistor elements each, and said output means comprising an operational amplifier having a pair of inputs biased by respective ones of said voltage divider circuits.
Claim 3
Dependent Claim
22 words
The system of claim 2, wherein one of said resistor elements includes said additional structure and the other resistor elements do not.
Claim 4
Dependent Claim
67 words
The system of claim 2, wherein the resistor element on the high voltage side of one voltage divider circuit and the resistor element on the low voltage side of the other voltage divider circuit include said additional structure and the other resistor elements do not, and the two resistor elements which include said additional structure are located proximate to each other to share a common magnetic field.
Claim 5
Dependent Claim
57 words
The system of claim 2, wherein all of said resistor elements include said additional structure, the resistor elements on the high voltage side of one voltage divider circuit and the low voltage side of the other voltage divider circuit being located proximate to each other, and the remaining resistor elements being spaced from the first resistor elements.
Claim 6
Dependent Claim
16 words
The system of claim 5, wherein said remaining resistor elements are located proximate to each other.
Claim 7
Dependent Claim
14 words
The system of claim 1, wherein said resistor elements are of substantially equal thicknesses.
Claim 8
Dependent Claim
35 words
The system of claim 1, said additional structure comprising an array of Hall effect shorting strips on its associated resistor element, said resistor elements operating as quasi-fixed resistors in the absence of said shorting strips.
Claim 9
Dependent Claim
18 words
The system of claim 8, wherein all of said resistor elements are fabricated on a common circuit chip.
Claim 10
Dependent Claim
12 words
The system of claim 1, said resistor elements being formed from InSb.
Claim 11
Dependent Claim
117 words
In a system for detecting the proximity of a magnetic material, said system including a magnet and a magnetic flux sensitive circuit positioned in the magnetic field from said magnet, said field increasing in strength in response to a magnetic material being positioned in proximity to said magnet, wherein the improvement comprises: said circuit being provided as a plurality of resistor elements each formed from the same type of resistor material, at least one of said resistor elements including an additional structure which renders it a magnetoresistor (MR), and output means interconnected with said resistor elements to produce an output which varies in accordance with changes in the magnetic field strength at said at least one MRs.
Claim 12
Dependent Claim
44 words
The system of claim 11, said resistor elements being arranged in a pair of voltage divider circuits of two resistor elements each, and said output means comprising an operational amplifier having a pair of inputs biased by respective ones of said voltage divider circuits.
Claim 13
Dependent Claim
22 words
The system of claim 12, wherein one of said resistor elements includes said additional structure and the other resistor elements do not.
Claim 14
Dependent Claim
65 words
The system of claim 12, wherein the resistor element on the high voltage side of one voltage divider circuit and the resistor element on the low voltage side of the other voltage divider circuit include said additional structure and the other resistor elements do not, and the two resistor elements which include said additional structure are located proximate to each other within the magnetic field.
Claim 15
Dependent Claim
91 words
The system of claim 12, wherein all of said resistor elements include said additional structure, the resistor elements on the high voltage side of one voltage divider circuit and the low voltage side of the other voltage divider circuit constituting a first pair and being located proximate to each other, and the remaining resistor elements constituting a second pair and being and spaced from said first pair, whereby the magnetic fields sensed by said first and second pairs change in opposite directions as a magnetic mass traverses along said resistor elements.
Claim 16
Dependent Claim
18 words
The system of claim 15, wherein said second pair of resistor elements are located proximate to each other.
Claim 17
Dependent Claim
31 words
The system of claim 15, wherein said first pair of resistor elements are aligned with said magnet, and said second pair of resistor elements are laterally offset from said first pair.
Claim 18
Independent Claim
125 words
A system for sensing changes in a magnetic field, comprising: a pair of voltage divider circuits, each circuit comprising first and second resistor elements connected in series, means for applying bias voltages across said voltage divider circuits to establish one resistor element of each circuit as a high voltage element and the other resistor element of each circuit as a low voltage element, the high voltage resistor element of one circuit and the low voltage resistor element of the other circuit comprising magnetoresistors, and the other resistor elements being substantially less responsive to magnetic fields than said magnetoresistors, and output means connected to said voltage divider circuits to produce an output which varies in accordance with changes in the magnetic field strength at said magnetoresistors.
Claim 19
Dependent Claim
22 words
The system of claim 18, wherein said magnetoresistors are located proximate to each other so as to share an applied magnetic field.
Claim 20
Independent Claim
181 words
A system for sensing changes in a magnetic field, comprising: a pair of voltage divider circuits, each circuit comprising first and second magnetoresistors connected in series, means for applying bias voltages across said voltage divider circuits to establish one magnetoresistor of each circuit as a high voltage element and the other one magnetoresistor of each circuit as a low voltage element, the high voltage magnetoresistor of one circuit and the low voltage magnetoresistor of the other circuit constituting a first pair and being located proximate to each other, and the low voltage magnetoresistor of said one circuit and the high voltage magnetoresistor of said other circuit constituting a second pair and being located spaced from said first pair, whereby the magnetic fields sensed by said first and second pairs change in opposite directions as field transverses from the vicinity of one pair to the vicinity of the other, and output means connected to said circuits to produce an output which varies in accordance with changes in the differential between the magnetic field strengths at said first and second pairs of magnetoresistors.
Claim 21
Dependent Claim
18 words
The system of claim 20, wherein said second pair of resistor elements are located proximate to each other.
Claim 22
Independent Claim
54 words
A method of forming a magnetic field sensing system comprising: forming a plurality of resistor elements substantially simultaneously, rendering at least one of said resistor elements magnetoresistive, and connecting said resistor elements to produce an output which varies in accordance with changes in the magnetic field strength at said at least one magnetoresistive element.
Claim 23
Dependent Claim
17 words
The method of claim 22, wherein each of said resistor elements are formed from a common material.
Claim 24
Dependent Claim
32 words
The method of claim 23 wherein, after the formation of each of said resistor elements, respective arrays of Hall effect shorting strips are formed on selected resistor elements to render them magnetoresistive.
Claim 25
Dependent Claim
18 words
The method of claim 22, wherein all of said resistor elements are formed on a common circuit chip.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.