Magnetic sensor and position detector
US5243280A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 17, 1992 |
| Grant date | Sep 7, 1993 |
| Priority date | — |
| Expiry date | Mar 17, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/09
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A magnetic sensor is disposed in an opposing relation to a magnetic scale in which a flat surface scale base made of a glass is plated by a magnetic material and a resultant plated layer is magnetized at a constant grating pitch. The magnetic sensor includes two magnetoresistance effect element groups disposed symmetrically with respect to a common central line. Since the surface of the magnetic scale is smooth, a clearance between the magnetic sensor and the magnetic scale can be kept substantially constant. When the magnetic sensor is moved in an opposing relation to the magnetic scale, a rise of temperature in the magnetoresistance effect elements is compensated for by the above symmetrical layout of the two magnetoresistance effect element groups. Therefore, when the magnetic sensor is moved over the magnetic scale in one direction and in the opposite direction, a dc fluctuation component in an output circuit can be reduced and the output circuit can generate a sine wave output of a constant amplitude having less waveform distortion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.