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:
Mar. 05, 1991
Filed:
Feb. 22, 1990
Muneshige Kurahashi, Tokorozawa, JP;
Naoki Kato, Tokyo, JP;
Nihon Kohden Corporation, Tokyo, JP;
Abstract
A two-wavelength type respiratory gas concentration measuring device includes a connector tube which is held in the mouth of an examinee and which has airtight windows, a light source which applies infrared rays through the windows of the connector tube, and first and second filters. The first filter allows the transmission of a light component whose wavelength is such that it is absorbed by the respiratory gas, and the second filter allows the transmission of a light component whose wavelength is such that it is not absorbed by the respiratory gas. A photodetector converts the infrared rays transmitted through the filters into an electric signal. A first detector receives the electric signal and detects the light output of the first filter. A second detector receives the electric signal and detects the light output of the second filter. A power computing circuit performs a power computation of the output of the second detector with a power exponent m. A divider circuit divides the output of the first detector by the output of the first power computing circuit. A DC level detector detects the DC level of the photodetector when no infrared rays are applied. A second power computing circuit performs a power computation of the output of the DC-level detector with a power exponent of 2(m-1). A multiplier circuit multiplies the output of the second power computing circuit by the output of the divider.