Piezoelectric resonator, and piezoelectric filter, duplexer, and communication apparatus, all including same
US6914368B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 12, 2002 |
| Grant date | Jul 5, 2005 |
| Priority date | — |
| Expiry date | Feb 5, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/568
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A piezoelectric resonator includes a substrate and a vibrator. The vibrator includes a thin-film portion having at least one piezoelectric thin-film layer disposed on the substrate and at least one pair of upper and lower electrodes disposed on the substrate. The vibrator has a structure in which the thin-film portion is sandwiched from the upper and lower surfaces thereof by the upper and lower electrodes, which oppose each other in the depth direction, and the overlapping portion of the vibrator defined by the opposing upper and lower electrodes has a tetragonal shape, when viewed in the depth direction, other than a rectangle and a square, the tetragonal shape having substantially parallel sides having a longitudinal length equal to or smaller than about 10 times the oscillatory wavelength and also having at least one portion in which the distance between opposing electrode edges varies.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.