Patent ID: 6340809
Filing Date: 2002-01-22
Classification: G01N

Abstract:
A gas sensor comprising:a gas sensing element having a gas-exposed portion, said gas sensing element having formed therein a chamber; a ceramic heater disposed within the chamber of said gas sensing element to heat said gas sensing element, said ceramic heater including, (a) a ceramic square rod formed with a laminate of a heater element substrate on which a heater-patterned layer consisting of a heater element and leads connected to the heater element is formed and a covering substrate covering the heater-patterned layer of the heater substrate, (b) metallic terminals connected electrically to the leads of the heater-patterned layer of the heater substrate, respectively, said metallic terminals being mounted on surfaces of said ceramic square rod opposed to each other in a direction of lamination of the heater substrate and the covering substrate, respectively, and (c) at least one outer lead joined to one of said metallic terminals through a bonding layer; a first cylindrical holder fitted in the chamber of said gas sensing element, said first holder including a heater holding portion for holding said ceramic heater and a sensor contact in contact with an inner wall of said gas sensing element, the sensor contact having a sensor signal output terminal; a second cylindrical holder mounted on an outer wall of said gas sensing element, having a sensor signal output terminal; and a slit formed in said first holder to define a C-shaped cross section, said slit being located substantially 90Â°Â±20Â° apart from the sensor signal output terminal of said first cylindrical holder.