The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 18, 2000
Filed:
Jul. 10, 1998
Kenneth L Girvin, Grants Pass, OR (US);
Richard K DeFreez, Azalea, OR (US);
Pacific Scientific Instruments Company, Grants Pass, OR (US);
Abstract
A particle counter (10) passes a sample stream of particles (72) through an elongated, flattened nozzle (16) and into a view volume (18) formed by an intersection of the sample stream and a laser beam (13). Scattered light (24) from the view volume is focused onto a linear array (32) of photodiode detectors (40) positioned such that a longitudinal length (70) of the view volume is imaged on the detectors. Because the sample stream produces nonuniform particle velocities along the longitudinal dimension of the view volume, for same-sized particles higher velocity particles will generate lower output amplitude signals than lower velocity particles. Therefore, the gain associated with each photo-detector element is adjustable to compensate for the nozzle velocity differences, laser beam intensity differences caused by beam divergence and fluctuations, optical path efficiency variations, and photo-detector element-to-element sensitivity differences.