Gas sensor
Patent 4399424 Issued on August 16, 1983. Estimated Expiration Date: 
October 5, 2001. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
October 5, 2001. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesInventorApplicationNo. 06/308290 filed on 10/05/1981US Classes:338/34, Gas, vapor, or moisture absorbing or collecting338/308, Resistance element coated on base338/309Terminal coated onExaminersPrimary: Albritton, C. L.Attorney, Agent or FirmInternational ClassG01N 27/12 (20060101)Foreign Application Priority Data1980-10-07 GBAbstractA semiconductor gas sensor comprises an insulating substrate (11) on which a resistive heater track (15) coupled to a pair of electrodes (12, 14) is deposited. A film (16) of a semiconductive metal oxide, typically a doped oxide, is ion-plated on to the assembly so as to contact the resistive track (15) and a further electrode (13). Exposure of the device to a particular gas, e.g. hydrogen sulphide, reduces the resistivity of the semiconductive film (16), this change being detected via an amplifier circuit (not shown). In an alternative version of the sensor (FIGS. 5a, 5b and 6) the heater is disposed under a dielectric layer, the semiconductive film being ion-plated onto the dielectric layer and electrodes therein. | |
