Patent ID: 6456375
Filing Date: 2002-09-24
Classification: D06F,G01N

Abstract:
A sensor for measuring low concentrations of particles in a viscous fluid, said sensor comprising:a VCSEL, wherein said VCSEL emits a laser light beam; a diffusing cone located opposite said VCSEL that captures incident light from the laser light beam through the viscous fluid and prevents reflection of the incident light back into the viscous fluid; a side scatter detector contained within a side scatter detector housing and located between said diffusing cone and said VCSEL proximate said laser light beam, wherein said side scatter detector housing is darkened to substantially eliminate ambient light and undesirable reflections, and wherein said side scatter detector monitors power associated with said VCSEL and reduces part-to-part variation of said VCSEL and is located in a vicinity of the incident light to thereby measure an intensity of said laser light beam; a forward scatter detector that detects forward-scattered light reflected from particles contained within said viscous fluid that come into contact with said laser light beam, wherein said forward scatter detector is located proximate said laser light beam and is contained within a forward scatter detector housing that is darkened to substantially eliminate ambient light and undesirable reflections; a radial side detector that detects radial-scattered light reflected from particles contained within said viscous fluid that come into contact with said laser light beam, wherein said radial side detector is located proximate said laser light beam; and a back scatter detector that detects back-scattered light reflected from particles contained within said viscous fluid that come into contact with said laser light beam, wherein said back scatter detector is located proximate said laser light beam, such that turbidity information is obtained from said side scatter detector, said forward scatter detector, said radial side detector and said back scatter detector to determine low concentrations of particles within said viscous fluid.