Highly sensitive particle size detection device having noise cancellation
US4893928A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 13, 1988 |
| Grant date | Jan 16, 1990 |
| Priority date | — |
| Expiry date | Sep 13, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/391
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A detection device is disclosed for determining particle size from particle effected light scattering in a sensing region illuminated by a laser beam and receiving the particles in a medium, such as air. Background light from molecular scattering is reduced to a level that enables light scattered by particles having a size of at least as low as about 0.1 micron to be sensed in a high background of molecular scattering such as, for example, where molecular scattering can exceed the 0.1 micron particle's scattering by one hundred times. High sensitivity at high molecular scattering background is achieved through use of a linear array of detectors positioned, with respect to an imaging system, so that each detector monitors a different portion of the sensing region and provides an electrical output signal indicative of sensed particle presence within that portion monitored, with the output signals from the detectors being parallel processed and with the output signals from detectors monitoring non-adjacent portions of the sensing region being combined at noise cancellation units.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.