Optical micropressure transducer
US4926696A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 19, 1986 |
| Grant date | May 22, 1990 |
| Priority date | — |
| Expiry date | Nov 19, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04R23/008
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A thin diaphragm receives pressure across one side and faces a beam splitter on the other side. The beam splitter is integrally attached to the diaphragm and serves as a local optical reference plane for the entire assembly. Coherent light from a light source is partially reflected at the beam splitter. The remainder of the light is reflected from the diaphragm. The reflected beams recombine at a detection point and have a phase difference which is a function of the amount of deflection of the diaphragm. The detected recombined beams are indicative of the deflection of the diaphragm. Optical calibration of the aseembly is a function of the distance between the diaphragm and beam splitter which remains as predefined because the beam splitter is integral with the diaphragm. A vent in the small cavity formed between the diaphragm and beam splitter enables the diaphragm to sense small pressures with increased sensitivity. Through micro-fabrication techniques, the diaphragm is made sensitive to dynamic and static pressure. Detection of the thermal expansion of the assembly as well as deflection of the diaphragm enables a sensed pressure measurement as a differential between the detected…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.