Sensor having dual Hall IC, pole piece and magnet
US4935698A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 3, 1989 |
| Grant date | Jun 19, 1990 |
| Priority date | — |
| Expiry date | Mar 3, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/14
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A Hall elements and magnet assembly for use as a proximity detector includes a magnet, a pole piece mounted to one pole end of the magnet and an integrated circuit having two side-by-side Hall elements, an amplifier, interconnecting wiring providing the difference voltage between the two Hall output voltages at the input of the amplifier, and a Schmitt trigger circuit. The integrated circuit is mounted to the pole piece at the pole end of the magnet. The pole piece is a ferromagnetic member which is thinner in the center than at the periphery for achieving a highly uniform field strength across the surface of the magnet pole end toward reducing the criticality of the position of mounting of the integrated circuit in manufacturing and for extending the range of gap dimensions between a passing ferromagnetic article and the assembly for which proper detection of the passing article can be made to occur. The term "ferromagnetic" as used herein means any material with a relative permeability greater than unity and preferably greater than 100.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.