Method and apparatus for optical discrimination of particles
AssigneeTechnicon Instruments Corporation
InventorsLawrence J. Coyne, Wilberdan V. George, Warren Groner
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Abstract
Method and apparatus for improved optical discrimination in a total particle population of particles having a significant light absorption characteristic and particles having a significant light scattering characteristic. There is provided in such a method a combination of steps including, directing a beam of light from a source to transversely illuminate at an optical interaction station particles passed one by one through such station, partially obstructing the beam beyond the station for passage of scattered and unscattered portions of the beam, when a particle is in said beam and detecting one of said beam portions.
Claims20
Apparatus for discriminating particles having particular light absorbing and scattering characteristics when illuminated by a beam of light, comprising:
- means for passing said particles, in turn, along an optical interaction station, a light source for directing a beam of light transversely through said station along an optical axis, and an optical detection system having an entrance aperture and including a photodetector for receiving light as scattered and absorbed by particles being passed, in turn, through said station, said detection system including means intermediate said station and said photodetector for partially obstructing an interior portion of said light beam while passing to said photodetector a portion of said scattered light which is substantially equal to the light which is scattered by said particles, in turn, outside said entrance aperture.
A method for discriminating particles having a particular light absorbing and light scattering characteristics when illuminated by a beam of light, comprising the steps of:
- passing said particles, in turn, along an optical interaction station, directing a beam of light from a light source transversely through said station along an optical axis, detecting light passed through said station as scattered and absorbed by each particle, in turn, by an optical detection system having an entrance aperture and a photodetector disposed along said optical axis, and partially obstructing an interior portion of said light beam passing to said photodetector at a location intermediate said station and said photodetector by an amount substantially equal to the light scattered by said particles, in turn, outside said entrance aperture.
Dependencies are inferred from the claim text.