Particle path determination system
US5133602A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 8, 1991 |
| Grant date | Jul 28, 1992 |
| Priority date | — |
| Expiry date | Apr 8, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/4792
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A bright-field, particle position determining optical system is disclosed that uses both phase shift and extinction signals to determine particle trajectories. In a first embodiment, a pair of orthogonally polarized beams are positioned along an axis that intersects a particle's flow path at an acute angle. An optical system recombines the beams after they exit the flow path, the combined beams manifesting an elliptical polarization if a particle intersects one of the beams. Bright field detectors detect polarization components of the combined beam, provide a phase shift signal between the beam's orthogonal components and provide corresponding signals to a processor. The processor determines a signal asymmetry from the phase shift signal that is indicative of a particle's position in the flow path. Another embodiment of the invention examines a signal resulting from the beam's phase shift and determines a correction factor that is dependent upon the distance of the particle from the focal plane of the beams. Another embodiment employs a dithering system for cyclically moving one or more optical beams across a particle to further enable its trajectory or position to be determined.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.