US4186367A
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Thick film varistor and method of producing same
Assignee: Siemens AG
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Filing: 1978-06-22
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Granted: 1980-01-29
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Expires: 1998-06-22
Abstract
Abstract A glass-free thick film varistor operable at operating voltages ranging from about 30 to 200 volts per mm of active varistor material is produced by providing a screen-printable paste comprised of a non-glass containing substantially homogeneous mixture of granular varistor materials which have ZnO as the main component thereof and an organic binder, applying such paste in a desired pattern onto an insulating substrate and sintering such applied paste at relatively high temperatures so as to convert the paste into thick film varistors.
Inventors
- 👤 Naresh Chakrabarty
- 👤 Richard Einzinger
- 👤 Artur Weitze
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:26
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/10; H01C7/1006; H01C17/00; H01C17/06; H01C17/065; H01C17/06506; H01C17/06513; H01C17/06533; H01C17/06546; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
138 words
In a method of producing thick-film varistors having zinc oxide as the main component thereof, the improvement comprising: forming a glass-free varistor paste by admixing varistor materials with an organic binding agent, said paste comprising, on a 100% by weight solid material basis, about 87.5% to 98.0% by weight of ZnO, about 1.0% to 7.0% by weight of Bi 2 O 3 , about 0.2% to 3.5% by weight Co 2 O 3 and about 0.1% to 1.0% by weight of MnO 2 ; applying a substantially uniform relatively thick layer of said varistor paste onto a surface of an insulating substrate; and sintering at least such paste layer at a temperature in the range of about 1100° C. to 1360° C. for a period of time sufficient to convert said paste layer into a thick film varistor.
Claim 2
Dependent Claim
138 words
In a method of producing thick-film varistors having zinc oxide as the main component thereof, the improvement comprising: forming a glass-free varistor paste by admixing varistor materials with an organic binding agent, said paste comprising, on a 100% by weight solid material basis, about 87.5% to 98.0% by weight of ZnO, about 1.0% to 7.0% by weight of Bi 2 O 3 , about 0.2% to 3.5% by weight Co 2 O 3 and about 0.1% to 1.0% by weight of MnO 2 ; applying a substantially uniform relatively thick layer of said varistor paste onto a surface of an insulating substrate; and sintering at least such paste layer at a temperature in the range of about 1100° C. to 1360° C. for a period of time sufficient to convert said paste layer into a thick film varistor.
Claim 3
Dependent Claim
87 words
In a method as defined in claim 1 wherein said varistor paste contains, on a 100% by weight solid material basis, about 87.5 to 98.0% by weight of ZnO, about 1.0 to 5.0 by weight of Bi 2 O 3 , about 0.3 to 2.0% by weight of Sb 2 O 3 , about 0.2 to 1.0% by weight of Cr 2 O 3 , about 0.5 to 3.5% by weight of Co 2 O 3 and about 0.1 to 1.0 by weight of MnO 2 .
Claim 4
Dependent Claim
84 words
In a method as defined in claim 1 wherein said varistor paste contains, on a 100% by weight solid material basis, about 87.5 to 96.5% by weight of ZnO, about 2.0 to 7.0% by weight of Bi 2 O 3 , about 0.2 to 1.0% by weight of Co 2 O 3 , about 0.2 to 1.0% by weight of MnO 2 , about 0.1 to 0.5 by weight % of SnO 2 and about 1.0 to 3.0% by weight of TiO 2 .
Claim 5
Dependent Claim
31 words
In a method as defined in claim 1 wherein during said sintering, a peak temperature within said range is maintained for a time period ranging between about 5 to 20 minutes.
Claim 6
Dependent Claim
27 words
In a method as defined in claim 1 wherein the sintered varistor is cooled at a temperature drop ranging between about 2° to 8° C. per minute.
Claim 7
Dependent Claim
38 words
In a method as defined in claim 1 wherein said varistor paste is applied onto said insulating substrate in amounts sufficient so that the sintered thick film varistor has a thickness ranging between about 100 and 200 μm.
Claim 8
Dependent Claim
132 words
A glass-free thick film varistor consisting essentially of a thick film comprised of a substantially homogeneous glass-free mixture containing, on a 100% by weight solid material, basis about 87.5 to 98.0% by weight of Zn, about 1.0 to 7.0% of Bi 2 O 3 , about 0.2 to 3.5% by weight of Co 2 O 3 , about 0.1 to 1.0% by weight of MnO 2 and a material selected from the group consisting of Sb 2 O 3 , Cr 2 O 3 , SnO 2 , TiO 2 and mixtures thereof in an amount sufficient to make a 100% by weight solid material within said thick film, and a pair of electrodes attached to said thick film, said varistor being characterized by a steepness value of at least above 20.
Claim 9
Dependent Claim
132 words
A glass-free thick film varistor consisting essentially of a thick film comprised of a substantially homogeneous glass-free mixture containing, on a 100% by weight solid material, basis about 87.5 to 98.0% by weight of Zn, about 1.0 to 7.0% of Bi 2 O 3 , about 0.2 to 3.5% by weight of Co 2 O 3 , about 0.1 to 1.0% by weight of MnO 2 and a material selected from the group consisting of Sb 2 O 3 , Cr 2 O 3 , SnO 2 , TiO 2 and mixtures thereof in an amount sufficient to make a 100% by weight solid material within said thick film, and a pair of electrodes attached to said thick film, said varistor being characterized by a steepness value of at least above 20.
Claim 10
Dependent Claim
120 words
A glass-free thick film varistor as defined in claim 7 wherein said thick film is comprised of, on a 100% by weight solid material, basis about 87.5 to 96.5% by weight of ZnO, about 1.0 to 5.0 by weight of Bi 2 O 3 , about 0.3 to 2.0% by weight of Sb 2 O 3 , about 0.2 to 1.0% by weight of Cr 2 O 3 , about 0.5 to 3.5% by weight of Co 2 O 3 and about 0.1 to 1.0 by weight of MnO 2 , said varistor being characterized by a steepness value of about 25 and being useful in an operating voltage range of about 200 volts per millimeter of active varistor material.
Claim 11
Dependent Claim
116 words
A glass-free thick film varistor as defined in claim 7 wherein said thick film is comprised of, on a 100% by weight solid material, basis about 87.5 to 96.5% by weight of ZnO, about 2.0 to 7.0% by weight of Bi 2 O 3 , about 0.2 to 1.0% by weight of Co 2 O 3 , about 0.2 to 1.0% by weight of MnO 2 , about 0.1 to 0.5 by weight % of SnO 2 and about 1.0 to 3.0% by weight of TiO 2 , said varistor being characterized by steepness value of about 25 and being useful in an operating voltage range of about 30 volts per millimeter of active varistor material.
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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) | 1983-01-28 | 1983-07-30 | 1984-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-01-28 | 1987-07-30 | 1988-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-01-28 | 1991-07-30 | 1992-01-29 | $7700.00 | Window Closed / Lapsed |