Filter device of piezo-electric type including divided co-planar electrodes
US5057801A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 20, 1990 |
| Grant date | Oct 15, 1991 |
| Priority date | — |
| Expiry date | Feb 20, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/178
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A piezoelectric filter device of an energy-trapped type utilizing a higher harmonic in the thickness-extensional vibration mode, having a plate-shaped body made of a piezoelectric material. At least three electrodes are arranged so as to overlap each other while being separated by layers of the piezoelectric material in the direction of thickness of the plate-shaped body. At least one of the electrodes comprises a plurality of divided electrodes which are substantially coplanar. At least one of the divided edlectrodes constitutes an input terminal and at least one of the remaining divided electrodes constitutes an output terminal. A region of the body, around the vibrating region, where the electrodes are overlapped with each other, is uniformly subjected to polarization processing in the direction of thickness.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.