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:
Jun. 11, 1985
Filed:
Jun. 08, 1983
Muneshige Kurahashi, Saitama, JP;
Shinji Yamamori, Tokyo, JP;
Nihon Kohden Corporation, Tokyo, JP;
Abstract
A respiratory gas concentration measuring apparatus includes a chopper having a first filter for passing therethrough light from a light source and having a first wavelength which can be absorbed by a gas to be measured and a second filter for passing therethrough light from the light source and having a second wavelength which cannot be absorbed by the gas. The chopper is rotatable to position the first and second filters alternately in a light path. The light having passed through the filters is converted by a photodetector into an electric signal. A first detector detects an output from the first filter based on the electric signal, and a second detector detects an output from the second filter based on the electric signal. The apparatus has a power computing circuit for raising an output from said second detector to an mth power, m being a power exponent preset in the power computing circuit, and a divider circuit for dividing an output from the first detector by an output from the power computing circuit. The power exponent m is the ratio between a temperature-dependent coefficient .theta..sub.1 of the output of the first detector which varies exponentially with a temperature variation and a temperature-dependent coefficient .theta..sub.2 of the output of the second detector which varies exponentially with a temperature variation.