| 摘要 |
PROBLEM TO BE SOLVED: To diagnose deterioration of a filter package before functions of a gas detector are lost and to perform preventive maintenance of the gas detector.SOLUTION: A gas detector 500 comprises a sensor element 50, energization drive means 60, gas detecting means 61, different-kind-of-gas determination means 62, and so on. The sensor element 50 is constituted of a silicon wafer 51 having a thermal oxidation film attached on both sides, on which a SiN(silicon nitride) film and a SiO(silica) film are successively formed as a support layer/heat insulation layer 52 of a diaphragm structure. After that, a heater layer 53 made of a Ni-Cr alloy and a SiOinsulation layer 54 are successively formed by a sputtering method. Then, a bonding layer 55, sensing layer electrodes 56, and a sensing layer 57 are formed thereon. Furthermore, a gas sensing layer 59 for sensing gas is formed as a film, and the gas sensing layer 59 is constituted of a sensing layer 57 of SnO(tin oxide) doped with Sb (antimony) and a selective combustion layer 58 constituted of a sintered material in which Pd (palladium) as a catalyst is carried by Al2O3 (alumina). |
