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:
Oct. 16, 1984
Filed:
Jan. 25, 1982
Donald R Pettit, Tucson, AZ (US);
Thomas W Peterson, Tucson, AZ (US);
University Patents, Inc., Norwalk, CT (US);
Abstract
The disclosed invention employs an optical heterodyne technique that depends upon coherent detection of phase modulated light from individual particles, and does not depend on measurement of light scattered at a specific angle from particles. A collimated coherent beam of light is generated and separated into a subject beam and a reference beam. The subject beam is focused at the inspection region and light is gathered from the inspection region. The gathered light and the reference beam are combined and a photodetector is responsive to the combined light for producing an electrical signal representative of the combined light. The phase shift of light scattered from an individual particle passing through the inspection region is then determined by measuring the power in the phase modulated sidebands of the electrical signal. The phase shift is indicative of the size of the particle passing through the inspection region.