Patent ID: 7722749

Claim:
A sensor comprising: a species selective electrode and a reference electrode having an electrolyte layer disposed therebetween; a reference gas channel in fluid communication with the reference electrode; a heater disposed in thermal communication with the sensor; a temperature sensor disposed in communication with the heater for maintaining the sensor at a desired operating temperature; wherein the species selective electrode is disposed on a first side of an insulating layer separating the species selective electrode from the electrolyte, the insulating layer having a first substantially solid area and a second area having an opening pattern extending through the insulating layer; the species selective electrode comprising a species sensing electrode portion comprising a first material disposed on the opening pattern of the insulating layer to extend inside at least one opening of the opening pattern so as to contact the electrolyte layer through the opening pattern and a non-active electrode lead portion comprising a second material that is different from the first material, the first material being deposited on top of the second material over the second area so that the non-active electrode lead portion is in electrical communication with the species sensing electrode portion, said non-active electrode lead portion disposed over the first substantially solid-area and the second area so as to substantially surround the periphery of at least one opening in the opening pattern while being sufficiently spaced from the periphery of each opening so as to be free from contact with the electrolyte layer; wherein both the species selective electrode and the reference electrode are in fluid communication with an exhaust atmosphere.