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:
Jul. 06, 2021
Filed:
Jul. 05, 2018
Hitachi Metals, Ltd., Tokyo, JP;
Kazuo Ono, Tokyo, JP;
Yoshitaka Sasago, Tokyo, JP;
Hitachi Metals, Ltd., Tokyo, JP;
Abstract
A gas sensor capable of stably detecting a gas concentration with a high reliability even under a high temperature environment is provided. The gas sensor includes an element unit having a capacitance value changing in accordance with a gas concentration, an inductor forming a resonant circuit in cooperation with the element unit, a phase detection circuit detecting a phase difference between a standard frequency and a resonant frequency of the resonant circuit, and a feedback unit supplying, to the element unit, a voltage changing in accordance with the phase difference detected by the phase detection circuit. The capacitance value of the element unit is controlled by the voltage from the feedback unit so as to reduce the phase difference between the resonant frequency and the standard frequency, and a gas concentration detection output is output based on the phase difference.