Method to detect non-spherical particles using orthogonally polarized light
US5637881A · kind A · utility
19Cited by
6References
10Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 11, 1995 |
| Grant date | Jun 10, 1997 |
| Priority date | — |
| Expiry date | Apr 11, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/21
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A structure and a method provide a quasi bright field particle sensor for the detection of non-spherical particles, using a laser beam of predetermined polarization. A phase shift caused by non-spherical particles passing through the laser beam is utilized to detect the presence of such particles. In one embodiment, a single laser beam is used to detect the concentration of non-spherical particles in the pump line receiving the exhaust gas from a process chamber.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.