EP0286307A2
Expired / Lapsed
EP
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Gas sensor
Assignee: Osmetech PLC
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Filing: 1988-03-30
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Granted: —
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Expires: 2008-03-30
Abstract
Abstract A gas sensor (30) has a layer of a semiconducting organic polymer, such as polypyrrole which is exposed to a gas to be detected. An alternating electric signal of varying frequency is applied to the sensor by an analyser (32), which detects the change in impedance characteristics of the sensor (30). The characteristics obtained are compared by microcomputer (36) with reference characteristics stored in a memory (38). The resulting difference spectra depend on the gas in contact with the sensor (30) and so the gas can be detected.
Inventors
- 👤 Peter Alfred Dept. Inst. Anal. Science Payne
- 👤 Jon Gillan Dept. Inst. Anal. Science Bartlett
- 👤 Natalie Karen Harris
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 11:03
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12; G01N27/125; G01N27/126; G01N27/122
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
83 words
A gas sensor comprising: a layer (14) of semiconducting organic polymer; generating means (32) for applying an electric signal to the layer; and detection means (36,38) for detecting the impedence characteristics of the layer (14) in the presence of the gas; characterised in that: the generating means (32) is adapted to generate an alternating signal and adapted to vary the frequency of that signal; and the detection (36,38) means is adapted to detect the variation in the impedence characteristics of the layer (14).
Claim 2
Dependent Claim
83 words
A gas sensor comprising: a layer (14) of semiconducting organic polymer; generating means (32) for applying an electric signal to the layer; and detection means (36,38) for detecting the impedence characteristics of the layer (14) in the presence of the gas; characterised in that: the generating means (32) is adapted to generate an alternating signal and adapted to vary the frequency of that signal; and the detection (36,38) means is adapted to detect the variation in the impedence characteristics of the layer (14).
Claim 3
Dependent Claim
47 words
A sensor according to claim 1, wherein the detection means comprises means (38) for storing a reference variation characteristic, and means (36) for comparing that reference variation characteristic with the variation in impedence characteristics of the layer (14) in the presence of the gas to be detected.
Claim 4
Dependent Claim
21 words
A sensor according to claim 1 or claim 2, wherein the semiconducting organic polymer is polypyrrole, poly-2-chloroaniline, poly-2-acetonitrile, polyindole, or poly-2-isobutylthiazole.
Claim 5
Independent Claim
71 words
A method of detecting a gas comprising: applying an electric signal to a layer of a semiconducting organic polymer, which layer is exposed to the gas; and investigating the impedence characteristics of the layer, thereby to detect the gas; characterised in that: the electric signal is an alternating signal, the frequency of which is varied, and the variation in impedence characteristics of the layer (14) is investigated to detect the gas.
Claim 6
Independent Claim
71 words
A method of detecting a gas comprising: applying an electric signal to a layer of a semiconducting organic polymer, which layer is exposed to the gas; and investigating the impedence characteristics of the layer, thereby to detect the gas; characterised in that: the electric signal is an alternating signal, the frequency of which is varied, and the variation in impedence characteristics of the layer (14) is investigated to detect the gas.
Claim 7
Dependent Claim
57 words
A method according to claim 4, wherein the investigation of the variation in impedence comprises: obtaining a reference variation by determining the variation in impedence characteristic of the layer when exposed to a reference gas, and comparing the reference variation with the variation in impedence characteristic of the layer when exposed to the gas to be detected.
Claim 8
Dependent Claim
20 words
A method according to claim 4 or claim 5, wherein the minimum frequency of the frequency variation is 1 MHz.
References Cited (Backward Citations)
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