Sensors
US4831304A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 21, 1988 |
| Grant date | May 16, 1989 |
| Priority date | — |
| Expiry date | Jan 21, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L9/002
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A solid sensor, for sensing a physical parameter such as pressure, comprises a resonantly vibratable beam formed across a cavity in a substrate by micro-machining, and arranged such that changes in the parameter vary its resonant frequency. The beam either consists of or has deposited on it a material exhibiting piezo-electric effect, so that vibration of the beam can be excited by using the effect. This is achieved using light, either by forming a photodiode in the substrate in or near the beam, so that illuminating the photodiode causes a voltage to be applied to the beam, or, in the case where the piezo-electric material exhibits surface piezo-electric effect, by directly illuminating the beam.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.