Wave filter and process for making same
US4103264A · kind A · utility
9Cited by
5References
7Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 30, 1976 |
| Grant date | Jul 25, 1978 |
| Priority date | — |
| Expiry date | Jan 30, 1996 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/42
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
In the manufacture of wave filters, such as FM filters, polarized piezoelectrically responsive wafers are provided, temporarily, on the active regions thereof, with a removable material. Subsequent to the encapsulation of the wafer by a protective but porous coating, the filter is heated and the removable material sublimates through the porous coating establishing a wafer surface substantially free of residual impurities and leaving an uninterrupted cavity between the wafer and the coating in the active regions. The preferred sublimatable material is paradichlorobenzene.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.