Optical sensor having a floatation means for detecting fluids through refractive index measurement
US5422495A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 15, 1993 |
| Grant date | Jun 6, 1995 |
| Priority date | — |
| Expiry date | Apr 15, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/431
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention provides methods and systems for sensing the presence of fluids, such as hydrocarbon-based liquids and/or water, in an ambient environment based upon their light refractive properties. An optical waveguide is deployed in the environment (or a sample chamber disposed within the environment), such that the transmittance of light through the waveguide is attenuated in the presence of the fluid analyte. In one preferred embodiment, the light source is aligned with the waveguide, such that the light entering the waveguide enters one end at an angle relative to the central axis of the waveguide and propagates by internal reflection within the waveguide. Optimal propagation occurs in the absence of the fluid while the presence to the fluid in contact with the waveguide walls causes detectable losses in light propagation due to degradation of the internal reflectance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.