Electret covered with an insulated film and an electret condenser having the electret
US7620192B2 · kind B2 · utility
9Cited by
17References
28Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 12, 2004 |
| Grant date | Nov 17, 2009 |
| Priority date | — |
| Expiry date | Jan 18, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R2499/11
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A silicon nitride film (103) and a silicon nitride film (106) are formed to cover a charged silicon oxide film (105) serving as an electret.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.