Patent ID: 7435321

Claim:
A proton conductor gas sensor having a sensor unit comprising a sensing element ( 4 ) comprising a proton conductive membrane ( 8 ); a membranal sensing electrode ( 10 ) and a membranal counter electrode ( 11 ) being separated from each other and attached at least on one face of the proton conductive membrane ( 8 ); a first metal plate ( 14 ) covering the sensing electrode and being provided with an opening ( 18 ), and a second metal plate ( 15 ) covering the counter electrode being characterized in that the first metal plate ( 14 ) is provided with a lead part ( 16 ), that the second metal plate is provided with a lead part ( 17 ), that said sensor unit additionally comprises a first synthetic resin film ( 20 ) having a thickness of 30 μm to 200 μm, and a second synthetic resin film ( 21 ) having a thickness of 30 μm to 200 μm, sandwiching the sensing element ( 4 ) between themselves and being greater in size than any of the proton conductive membrane ( 8 ), the sensing electrode ( 10 ), the counter electrode ( 11 ), the first and the second metal plates ( 14 , 15 ), that the first and second synthetic resin films ( 20 , 21 ) are bonded together, and by that, the first metal plate ( 14 ) is pressed towards the sensing electrode side and the second metal plate ( 15 ) is pressed towards the counter electrode side, and an electric contact between the first metal plate ( 14 ) and the sensing electrode ( 10 ) and an electric contact between the second metal plate ( 15 ) and the counter electrode ( 11 ) are secured, and that the respective lead parts protrude from and between the first and the second synthetic resin films outwards.