Sensors and methods for high-sensitivity optical particle counting and sizing
US7127356B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 18, 2004 |
| Grant date | Oct 24, 2006 |
| Priority date | — |
| Expiry date | May 18, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2015/1486
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A single-particle optical sensor, which has high sensitivity and responds to relatively concentrated suspensions, uses a relatively narrow light beam to illuminate an optical sensing zone nonuniformly. The zone is smaller than the flow channel so that the sensor responds to only a fraction of the total number of particles flowing through the channel, detecting a statistically significant number of particles of any relevant diameter. Because different particle trajectories flow through different parts of the zone illuminated at different intensities, it is necessary to deconvolute the result. Two methods of deconvolution are used: modified matrix inversion or successive subtraction. Both methods use a few basis vectors measured empirically or computed from a theoretical model, and the remaining basis vectors are derived from these few. The sensor is compensated for turbidity. Several embodiments are disclosed employing light-extinction or light-scattering detection, or both.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.