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:
Nov. 21, 2000
Filed:
Dec. 21, 1994
Applicant:
Inventors:
Bruce W McCaul, Palo Alto, CA (US);
David E Doggett, Sunnyvale, CA (US);
Assignee:
Other;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01N / ;
U.S. Cl.
CPC ...
250343 ; 2503413 ;
Abstract
An absorption spectroscopy device for determining the concentration of a gas (such as oxygen) in a sample cell includes a neutral density absorber or a quarter wave plate. Laser radiation from a laser diode passes through the neutral density absorber or the quarter wave plate, then passes through the sample cell, and then is incident upon a detector. In some embodiments, the laser diode is driven with a drive current having a stepped periodic waveform.