US4481499A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gas detector
Assignee: Hitachi Ltd
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Filing: 1983-04-27
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Granted: 1984-11-06
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Expires: 2003-04-27
Abstract
Abstract A gas detector with a layer of gas sensing material comprising an oxide semiconductor, wherein at least one coating layer each of a p-type oxide semiconductor and an n-type oxide semiconductor is provided in a multi-layer arrangement on the surface of said layer of gas sensing material that contacts the gas. The gas detector can selectively identify only specific gases.
Inventors
- 👤 Hideo Arima
- 👤 Masayoshi Kaneyasu
- 👤 Mitsuko Ito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:45
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
150 words
A gas detector which comprises a layer of gas sensing material comprising a p-type oxide semiconductor or an n-type oxide semiconductor, and at least one pair of coating layers comprising a layer containing a p-type oxide semiconductor and a layer containing an n-type oxide semiconductor provided in a multilayer arrangement on the surface of said layer of gas sensing material that contacts the gas, wherein when the gas sensing material comprises a p-type oxide semiconductor, the at least one pair of coating layers is formed in the order of a coating layer containing an n-type oxide semiconductor followed by a coating layer containing a p-type oxide semiconductor and when the gas sensing material comprises an n-type oxide semiconductor, the at least one pair of coating layers is formed in the order of a coating layer containing a p-type oxide semiconductor following by a coating layer containing an n-type oxide semiconductor.
Claim 2
Dependent Claim
150 words
A gas detector which comprises a layer of gas sensing material comprising a p-type oxide semiconductor or an n-type oxide semiconductor, and at least one pair of coating layers comprising a layer containing a p-type oxide semiconductor and a layer containing an n-type oxide semiconductor provided in a multilayer arrangement on the surface of said layer of gas sensing material that contacts the gas, wherein when the gas sensing material comprises a p-type oxide semiconductor, the at least one pair of coating layers is formed in the order of a coating layer containing an n-type oxide semiconductor followed by a coating layer containing a p-type oxide semiconductor and when the gas sensing material comprises an n-type oxide semiconductor, the at least one pair of coating layers is formed in the order of a coating layer containing a p-type oxide semiconductor following by a coating layer containing an n-type oxide semiconductor.
Claim 3
Dependent Claim
39 words
A gas detector according to claim 1 wherein the p-type oxide semiconductor in the coating layer is selected from the group consisting of NiO, LaNiO 3 , and the spinel-type material (Mn, Co, Ni, Al) 3 O 4 .
Claim 4
Dependent Claim
48 words
A gas detector according to claim 1 wherein the n-type semiconductor in the coating layer is selected from the group consisting of SnO 2 , WO 3 , Ta 2 O 5 , ZnO, Fe 2 O 3 , TiO 2 , and Nb 2 O 5 .
Claim 5
Dependent Claim
104 words
A gas detector according to claim 1, wherein the p-type oxide semiconductor coating layer contains a p-type oxide semiconductor selected from a group consisting of NiO, LaNiO 3 , and a spinel-type material (Mn, Co, Ni, Al) 3 O 4 ; the n-type oxide semiconductor coating layer contains an n-type oxide semiconductor selected from the group consisting of SnO 2 , WO 3 , Ta 2 O 5 , ZnO, Fe 2 O 3 , TiO 2 and Nb 2 O 5 ; and the gas sensing material contains an oxide semiconductor selected from the group consisting of SnO 2 , ZnO and NiO.
Claim 6
Dependent Claim
17 words
A gas detector according to claim 1, wherein said gas sensing material comprises an n-type oxide semiconductor.
Claim 7
Dependent Claim
48 words
A gas detector according to claim 5, wherein a coating layer containing a p-type oxide semiconductor is formed on the surface of said layer of gas sensing material, and a coating layer containing an n-type oxide semiconductor is formed on said coating layer containing said p-type oxide semiconductor.
Claim 8
Dependent Claim
17 words
A gas detector according to claim 1, wherein said gas sensing material comprises a p-type oxide semiconductor.
Claim 9
Dependent Claim
48 words
A gas detector according to claim 7, wherein a coating layer containing an n-type oxide semiconductor is formed on the surface of said layer containing gas sensing material, and a coating layer containing a p-type oxide semiconductor is formed on said coaing layer of said n-type oxide semiconductor.
Claim 10
Dependent Claim
36 words
A gas detector according to claim 6, wherein alternating successive pairs of coating layers containing said p-type and n-type oxide semiconductors are provided in a multilayer arrangement on said coating layer containing an n-type oxide semiconductor.
Claim 11
Dependent Claim
36 words
A gas detector according to claim 8, wherein alternating successive pairs of coating layers containing said n-type and p-type oxide semiconductors are provided in a multilayer arrangement on said coating layer containing a p-type oxide semiconductor.
Claim 12
Dependent Claim
25 words
A gas detector according to claim 1, wherein the layer containing the gas sensing material also contains platinum metal and PbO--TiO 2 --SiO 2 glass.
Claim 13
Dependent Claim
23 words
A gas detector according to claim 1, wherein the coating layer containing the p-type oxide semiconductor also contains PbO--TiO 2 --SiO 2 glass.
Claim 14
Dependent Claim
23 words
A gas detector according to claim 1, wherein the coating layer containing the n-type oxide semiconductor also contains PbO--TiO 2 --SiO 2 glass.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-11-06 | 1988-05-07 | 1988-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-06 | 1992-05-07 | 1992-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-06 | 1996-05-07 | 1996-11-06 | $7700.00 | Window Closed / Lapsed |