Patent US5955938A successfully refreshed from Google Patents.
US5955938A
Expired / Lapsed
US
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RuO2 resistor paste, substrate and overcoat system
Assignee: Murata Manufacturing Co Ltd
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Filing: 1997-11-26
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Granted: 1999-09-21
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Expires: 2017-11-26
Abstract
Abstract A ceramic circuit substrate having a resistor deposited on a surface thereof, said ceramic substrate having a coefficient of thermal expansion ranging from 5.0x10-6/ DEG C. to 7.0x10-6/ DEG C., the resistor being coated with a glass overcoat and made of 15 to 50% of RuO2 and 85 to 50% of a CaO-Al2O3-SiO2-B2O3-system glass, the glass overcoat being made of 60 to 100% of a CaO-Al2O3-SiO2-B2O3-system glass and up to 40% of alumina, wherein the resistor has a coefficient of thermal expansion greater than that of the glass overcoat. Due to the above specific relationship between the coefficient of thermal expansion of the resistor and that of the overcoat, the resistor is not subject to cracking at the time of trimming and thereafter, and realizes the exertion of resistance performance ensuring excellent weather resistance and stability.
Inventors
- 👤 Masashi Fukaya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:15
CPC Classifications
H; H10; H10D; H10D1/00; H10D1/40; H10D1/47; H10D1/474
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
111 words
A ceramic circuit substrate having a resistor deposited on a surface thereof, said ceramic substrate having a coefficient of thermal expansion ranging from 5.0×10 -6 /° C. to 7.0×10 -6 /° C., the resistor being coated with a glass overcoat and consisting essentially of 15 to 50% of RuO 2 and 85 to 50% of a CaO--Al 2 O 3 --SiO 2 --B 2 O 3 glass, the glass overcoat consisting essentially of 60 to 100% of a CaO--Al 2 O 3 --SiO 2 --B 2 O 3 glass and up to 40% of alumina, wherein the resistor has a coefficient of thermal expansion greater than that of the glass overcoat.
Claim 2
Dependent Claim
111 words
A ceramic circuit substrate having a resistor deposited on a surface thereof, said ceramic substrate having a coefficient of thermal expansion ranging from 5.0×10 -6 /° C. to 7.0×10 -6 /° C., the resistor being coated with a glass overcoat and consisting essentially of 15 to 50% of RuO 2 and 85 to 50% of a CaO--Al 2 O 3 --SiO 2 --B 2 O 3 glass, the glass overcoat consisting essentially of 60 to 100% of a CaO--Al 2 O 3 --SiO 2 --B 2 O 3 glass and up to 40% of alumina, wherein the resistor has a coefficient of thermal expansion greater than that of the glass overcoat.
Claim 3
Dependent Claim
39 words
The ceramic circuit substrate of claim 1, wherein said ceramic substrate is prepared by firing a CaO--SiO 2 --Al 2 O 3 --B 2 O 3 glass or MgO--SiO 2 --Al 2 O 3 --B 2 O 3 glass.
Claim 4
Dependent Claim
47 words
The ceramic circuit substrate of claim 1, wherein said glass in the resistor consists essentially of 21.3 to 35.7% of CaO, 3.3 to 18.8% of Al 2 O 3 , 35.7 to 56.2% of SiO 2 , and 7.1 to 33.3% of B 2 O 3 .
Claim 5
Dependent Claim
36 words
The ceramic circuit substrate of claim 1, wherein said glass overcoat consists essentially of 60 to 90% of the CaO--Al 2 O 3 --SiO 2 --B 2 O 3 glass and 10 to 40% of alumina.
Claim 6
Dependent Claim
57 words
The ceramic circuit substrate of claim 4, wherein said glass in the glass overcoat consists essentially of 19.9 to 27.2% of CaO, 5.2 to 15.4% of Al 2 O 3 , 52.1 to 58% of SiO 2 , 8.7 to 16.4% of B 2 O 3 , and 0.1 to 1.5% of Cr 2 O 3 .
Claim 7
Dependent Claim
68 words
The ceramic circuit substrate of claim 1, wherein said ceramic substrate has a coefficient of thermal expansion of from 5.0×10 -6 /° C. to 6.9×10 -6 /° C., said resistor has a coefficient of thermal expansion of from 5.5×10 -6 /° C. to 6.5×10 -6 /° C. and said glass overcoat has a coefficient of thermal expansion of from 5.3×10 -6 /° C. to 6.4×10 -6 /° C.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2002-09-20 | 2003-03-22 | 2003-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-09-20 | 2007-03-22 | 2007-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-09-20 | 2011-03-22 | 2011-09-21 | $7700.00 | Window Closed / Lapsed |