Patent US4396899A successfully refreshed from Google Patents.
US4396899A
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Platinum thin film resistance element and production method therefor
Assignee: KIRK 16-1 NISHI-SHINBASHI 2-CHOME MINATO-KU TOKYO JAPAN A CORP OF JAPAN KK
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Filing: 1981-03-30
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Granted: 1983-08-02
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Expires: 2001-03-30
Abstract
Abstract A platinum thin film is formed by sputtering platinum onto an insulating substrate and heat aging the platinum thin film in a stairstep manner. A kerf is formed in the platinum thin film to produce a desired resistance, and a metal oxide semiconductor film is thereafter deposited on the platinum thin film to produce a gas sensor.
Inventors
- 👤 Yoshio Ohno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:19
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/22; H01C13/00; H01C17/00; H01C17/06; H01C17/075; H01C17/12
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
148 words
A gas sensor comprising a platinum thin film resistance element which includes: an insulating substrate having a smooth surface the unevenness of which is less than 1.1 μm; a substantially pure platinum thin film formed as a continuous, solid film to a thickness of 100 to 1000 A on said surface of the insulating substrate, the resistance value of said thin film being stabilized by sputtering platinum particles forming said film onto said surface and by thereafter heat aging said film at temperatures from about 100° C. to about 1000° C. in a step-wise manner, said film having a kerf formed therein to increase its resistance value; a metal oxide semiconductor film formed on the platinum thin film to adsorb a gas to be sensed; and a pair of lead wires electrically connected to opposite end portions of the platinum thin film and fixed to the insulating substrate.
Claim 2
Dependent Claim
148 words
A gas sensor comprising a platinum thin film resistance element which includes: an insulating substrate having a smooth surface the unevenness of which is less than 1.1 μm; a substantially pure platinum thin film formed as a continuous, solid film to a thickness of 100 to 1000 A on said surface of the insulating substrate, the resistance value of said thin film being stabilized by sputtering platinum particles forming said film onto said surface and by thereafter heat aging said film at temperatures from about 100° C. to about 1000° C. in a step-wise manner, said film having a kerf formed therein to increase its resistance value; a metal oxide semiconductor film formed on the platinum thin film to adsorb a gas to be sensed; and a pair of lead wires electrically connected to opposite end portions of the platinum thin film and fixed to the insulating substrate.
Claim 3
Dependent Claim
29 words
A gas sensor according to claim 1 wherein the resistance value of the metal oxide semiconductor film is significantly larger than the resistance value of the platinum thin film.
Claim 4
Dependent Claim
35 words
A gas sensor according to claim 1 wherein a protective layer is interposed between the platinum thin film and the metal oxide semiconductor film to prevent the diffusion therethrough of components of the two films.
Claim 5
Dependent Claim
16 words
A gas sensor according to claim 3 wherein the protective layer is formed of alumina cement.
Claim 6
Dependent Claim
16 words
A gas sensor according to claim 3 wherein the protective layer is formed of beryllium cement.
Claim 7
Dependent Claim
19 words
A gas sensor according to claim 1 or 3 wherein means is provided for electrically heating the insulating substrate.
Claim 8
Dependent Claim
29 words
A gas sensor according to any one of claims 1 or 2 to 5 wherein the metal oxide semiconductor film is operative to adsorb and release an inflammable gas.
Claim 9
Dependent Claim
25 words
A gas sensor according to any one of claims 1 or 2 to 5 wherein the metal oxide semiconductor film is formed of copper oxide.
Claim 10
Dependent Claim
57 words
A gas sensor according to any one of claims 1 or 2 to 5 wherein the metal oxide semiconductor film is formed of a mixture including 10 to 30 wt% of an oxide of a rare earth and 0.5 to 5 wt% of silver nitrate AgNO 3 with respect to vanadium pentoxide V 2 O 5 .
Claim 11
Dependent Claim
65 words
A gas sensor according to any one of claims 1 or 2 to 5 wherein the metal oxide semiconductor film is formed of a mixture including 3 to 10 wt% of samarium pentoxide SmO 5 , 1 to 5 wt% of antimony trioxide Sb 2 O 3 and 0.5 to 5 wt% of silver nitrate with respect to vanadium pentoxide V 2 O 5 .
References Cited (Backward Citations)
US2357473A
Cited
US3699803A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-01 | 1987-01-31 | 1987-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-01 | 1991-01-31 | 1991-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-01 | 1995-01-31 | 1995-08-02 | $7700.00 | Window Closed / Lapsed |