Temperature compensated piezoelectric buzzer
US8908889B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 15, 2013 |
| Grant date | Dec 9, 2014 |
| Priority date | — |
| Expiry date | Aug 24, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B21/0446
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A buzzer includes a piezoelectric diaphragm and a housing enclosing the diaphragm and defining a resonating chamber. The chamber includes a sound port and has an optimal resonating frequency fHt at a temperature T defined by fHt=(vt/2π)(√(A/voL)) were vt is the velocity of sound waves in air at a temperature T, A is the effective area of the sound port, vo is the volume of the resonating chamber, and L is the effective length of the sound port. A temperature compensating member moves in response to changes in temperature to change the value of √(A/voL) at a rate and in a manner that balances the change in 1/vt across that same temperature range, thereby reducing changes in the product (vt/2π)(√(A/voL)) and consequently reducing any changes that would otherwise occur in fHt across that temperature range, thereby holding the value of fH substantially constant across the temperature range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.