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US 2004/0070756 A1Published application
Optical detection of particles in a liquid medium
AssigneeRusteck Limited
InventorStanislav Rastopov
Life of this patent
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AssigneeRusteck Limited
InventorStanislav Rastopov
Estimating the term…
Particles in a liquid medium are detected by directing a source of laser light through a container containing a liquid sample with a concentration of microscopic particles in suspension. An optical detector located off the optical axis receives scattered light from the particles and provides a signal with a dc component and a varying component. The DC component is removed to provide a filtered signal representing the varying component. Movement is produced in the sample liquid, e.g., by convective stirring, to extend the band of frequencies of the varying component towards higher frequencies. The apparatus can be used for growth curve detection of biological samples and provides increased sensitivity.
Optical apparatus for detecting particles in a liquid medium, comprising
Apparatus as claimed in any preceding claim, including at least a first matched pair of said detectors equally spaced at a common radial distance on opposite sides of a plane containing said optical axis, and difference means receiving input signals respectively from said pair of detectors and providing a difference signal representing the difference between said input signals.
A method of growth curve analysis of a liquid biological sample comprising preparing a liquid sample for analysis containing a selected growth medium, illuminating a volume of said sample with coherent light directed along an optical axis, detecting the intensity of light scattered from said illuminated volume, filtering out a dc component of said deleted intensity to provide a filtered signal representing only intensity variations in a predetermined band of frequencies monitoring said filtered signal over a period of time, and determining from changes in said filtered signal the likely presence or absence of a biological species which is viable in the selected growth medium.
Dependencies are inferred from the claim text.