Electret transducer with a selectively metalized backplate
US4429189A · kind A · utility
4Cited by
5References
14Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 20, 1981 |
| Grant date | Jan 31, 1984 |
| Priority date | — |
| Expiry date | Nov 20, 2001 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49226
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An electret transducer comprises an electrostatically charged electret foil (10) superimposed directly over a selectively metalized rough surface (16) of a backplate (18). Selective metalization is realized by depositing a thin metal layer (20), the contour of which is defined by a predetermined relationship, over the rough surface (16). The sensitivity of the electret transducer at any point thereon is directly proportional to the width of the metal layer on the backplate. The response characteristic of the electret transducer comprises a main lobe and a plurality of sidelobes below a preselected threshold.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.