Surface acoustic wave sensors
US4535631A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 29, 1982 |
| Grant date | Aug 20, 1985 |
| Priority date | — |
| Expiry date | Sep 29, 2002 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S73/04
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Pressure sensing diaphragms comprise a cylindrical or spherical crystalline member in which an internal cylindrical or spherical chamber is provided. In the internally loaded embodiments, a fluid is introduced into the chamber and the pressure exerted by the fluid causes generally tensile stress in the region of the diaphragm generally about the chamber. In the externally loaded embodiments, the diaphragm is immersed within the fluid and the pressure exerted by the fluid causes generally compressive stress in the region of the diaphragm generally about the chamber. For each of the embodiments, the stresses arising cause certain mechanical and electrical properties of the crystalline material to change. The change in these properties is detected by observing the frequency behavior of one or more oscillators whose frequencies of operation are controlled by respective surface acoustic wave devices provided in the regions of elastic deformation. Many diaphragm arrangements are capable of providing temperature compensated pressure measurements. Two particularly useful orientations for the temperature compensated embodiments are the SST and ST orientations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.