Ceramic heater for oxygen sensor of the type having oxygen ion conductive tube of solid electrolyte

摘要

In an oxygen sensor of the type having an oxygen ion conductive tube of solid electrolyte, a ceramic heater disposed within the oxygen ion conductive tube for heating the same is in the form of a quadrangular prism or a bar of a rectangular cross section. The ceramic heater is formed by piling up ceramic green sheets with metallic thick- film patterns for heat generating resistors interposed between adjacent two of the ceramic green sheets. The ceramic heater is so shaped as to satisfy the relation of b/a=0.75˜1 where "a" is the width and "b" is the thickness of the ceramic heater. The metallic thick films, which the metallic thick-film patterns are turned to by firing, are arranged so as to be parallel to the side surfaces opposed in the thickness direction of the ceramic heater.