Method and apparatus for implanting a charge in an electret foil
US4348711A · kind A · utility
3Cited by
6References
20Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 25, 1980 |
| Grant date | Sep 7, 1982 |
| Priority date | — |
| Expiry date | Jun 25, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01G7/023
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
In previously proposed arrangements for charging an electret foil the electret charge implanted varies over the area of the foil. In order to promote more even charging of the foil, the method of the invention subjects the foil to a progressively increasing electric field. One form of apparatus used to carry out the method has rollers at progressively higher potentials and electric fields are applied across the foil between these rollers and a metallized layer on the rear face of the foil which is earthed by a roller.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.