Koa Corporation

Ken Takahashi

Kenichi Iguchi

Chika Ito

Tetsuro Tanaka

A sensor element () has a cross-sectional area that continuously only increases from a positive (+) electrode side toward a negative (−) electrode side, thereby leading a hot spot, which attempts to move to the negative electrode side, to a lower resistance side. A position that is at nearly equal distances from paired electrodes (and) formed on either end of the sensor element () is set as a hot spot generating position, so as to avoid damage to the electrodes due to heat emitted by the hot spot.

Gas sensor

An oxygen sensor for detecting gas concentration based on either an electric current value or a resistance value measured when a voltage is applied to a sensor element includes gaps formed between electrodes arranged in an element main body and ridges where surfaces of an element touch each other. These gaps will be escaping parts for expansion and contraction of electrode material that accompany thermal expansion and contraction of a sensor main body, and concentration of thermal stress at edge parts of the element main body may thus be eliminated, thereby alleviating thermal stress on the oxygen sensor. This allows provision of a gas sensor that controls generation of cracks in the element and that is stably usable over a long period of time.

Growing community of inventors

MINOWA-MACHI, Japan

Ken Takahashi