Gas sensor
US4399424A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 5, 1981 |
| Grant date | Aug 16, 1983 |
| Priority date | — |
| Expiry date | Oct 5, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N27/12
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A 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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.