Nihon Parkerizing Co., Ltd.

Yasuo Imai

Kentaro Nagano

Yasunobu Matsushima

Ryuji Kojima

Kazuhiro Ishikura

Yoshio Moriya

This invention concerns a humidity sensor wherein a chemical conversion coating, giving attention to the property that it undergoes an impedance decrease with adsorption of moisture, is used as humidity sensing element which is characterizied by an extremely short electrode distance, greatly improved sensitivity, high speed response, stable performance over a long period of time, high reliability and cheaper production cost. The principal point that characterizes the humidity sensor in this invention is that the chemical conversion coating deposited on the metal surface with or without an electrolysis application, is made usable as a humidity sensing element. For the chemical conversion coating, such coatings as phosphate, oxalate, titanium fluoro-complex, chromium phosphate and non-chromium types are used. On top of this chemical conversion coating, application of a humidity sensing film is effected to further improve humidity sensing performance.

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Yokohama, Japan

Yasuo Imai