Magnetically responsive device for measuring the thickness of magnetic films
US6538434B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 30, 2000 |
| Grant date | Mar 25, 2003 |
| Priority date | — |
| Expiry date | Dec 9, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/105
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A device for measuring the thickness of films or coatings on bases wherein the film thickness is determined from the magnetic adhesive force of a permanent magnet on the surface of the film to be measured. The device includes a permanent magnet attached to an end of a lever arm mounted at its center of gravity, forming a rotary system which includes an electromagnet counterbalancing the permanent magnet. The magnetic adhesive force between the permanent magnet and film is overcome by the variable force of the magnetic field of the electromagnet acting on the lever arm of the rotary system, the value of which, as the permanent magnet is lifted off the film, is used as a measure of the film thickness. In the best mode of operation, this is accomplished by integrating the time required to raise the current applied to the electromagnet to the value which generates a magnetic field which overcomes the adhesive force between the film and permanent magnet.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.