Electrets
US4291245A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 4, 1979 |
| Grant date | Sep 22, 1981 |
| Priority date | — |
| Expiry date | Sep 4, 1999 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31692
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A process for preparing polymer electrets comprising the following steps: PA1 (a) providing a parylene film having one side affixed to a metal layer and grounding said metal layer; PA1 (b) charging the free side of the film with a direct current corona, the charge being of sufficient magnitude to convert the film to an electret; PA1 (c) providing p-xylylene monomer vapor in sufficient amount to coat the charged film; and PA1 (d) introducing the vapor from step (c) and the electret into a deposition zone, said zone being under vacuum and at a temperature at which the vapor will condense, whereby the electret is conformally coated with parylene.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.