Improved particle sensor and method for assaying a particle
US5467189A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 12, 1995 |
| Grant date | Nov 14, 1995 |
| Priority date | — |
| Expiry date | Jan 12, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/6469
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The disclosure involves a particle sensor having a mirror cavity unobstructed by masks and the like. A light detector is at the mirror secondary focal point and well outside the mirror cavity. A variation includes a beam splitter and a secondary light detector to improve detection of larger particles. A second embodiment includes a pair of elliptical mirrors offset along the light beam. Light reflected by the second mirror represents only changes in laser power and light scattered by gas molecules. The resulting signal is subtracted from that produced by the first mirror to obtain a relatively "clean" signal useful to assay very small particles.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.