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. 10, 1995
Filed:
Dec. 03, 1993
Eugene I Gordon, Mountainside, NJ (US);
Sleepair Corporation, Mountainside, NJ (US);
Abstract
An apparatus for ultrasensitive detection of low concentrations of constituents using a broad band LED source is described. The apparatus provides enhanced resolution by synchronously detecting an imbalance between two analog signals due to absorption in a measurement cell at a wavelength of interest. Elements are provided to balance the signals in the absence of absorption to provide a reference point for concentration calculations. In accordance with several embodiments of the present invention, a time alternating signal for synchronous detection is achieved by combining signals from each of two alternating paths, only one of which travels through the measurement cell and which may have absorption. If there is absorption in the measurement cell, then the signal created by combining the alternating paths will exhibit residual modulation at the path alternation rate. In accordance with another embodiment of the present invention, a time alternating signal is achieved by combining signals from each of two alternating ultranarrow wavelength channels, each of which travels through the measurement cell but only one of which is on an absorption line of a constituent believed to be in the measurement cell, into a single photosensitive device. If there is absorption in the measurement cell, then the signal from the photosensitive device formed by combining the alternating wavelength channels will exhibit residual modulation at the wavelength channel alternation rate.