Sensor having an electric coil and giant magnetoresistor for detecting defects in a component
US6693425B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 11, 2002 |
| Grant date | Feb 17, 2004 |
| Priority date | — |
| Expiry date | Oct 11, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N27/902
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A sensor for detecting defects in a component includes an electric coil fed with a varying electrical current to create a varying magnetic field penetrating at least partly into the component under test, and a defect detector including a magnetoresistor. The above components are accommodated in a protective housing having a detection face disposed near and parallel to a surface of the component under test. The coil has its axis &Dgr; perpendicular to the detection face and the magnetoresistor is in the vicinity of the detection face. The magnetoresistor is a giant magnetoresistor and is disposed so that its sensitivity axis &Dgr;1 sensitive to variations in a magnetic field is parallel to the detection face of the housing. The sensor further includes a first permanent magnet disposed so that it magnetically biases the magnetoresistor in the direction of its sensitive axis &Dgr;1 to a value such that the operating point is a point on a curve, representing the output signal of the magnetoresistor as a function of the value of the component of the magnetic field in the direction of the sensitive axis, which is situated in the vicinity of the middle of a substantially rectilinear porti…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.