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US5378408A
Expired / Lapsed
US
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Lead-free thick film paste composition
Assignee: EIDP Inc
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Filing: 1993-07-29
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Granted: 1995-01-03
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Expires: 2013-07-29
Abstract
Abstract A screen-printable thick film paste composition suitable for forming conductive patterns on a rigid substrate comprising: (a) finely divided particles of a lead-free glass composition having a softening point log (eta)=7.6 poise from 400° C.-650° C., a log (eta.) specific viscosity in a range from 2 at 500° C. to 5 at 700° C. and consisting essentially of, by weight 65-95% Bi 2 O 3 , 2-15% SiO 2 , 0.1-9% B 2 O 3 , 0-5% Al 2 O 3 , 0-5% CaO, and 0-20% ZnO; and (b) electrically conductive particles; and all of (a) and (b) being dispersed in (c) an organic medium.
Inventors
- 👤 Alan F. Carroll
- 👤 Kenneth W. Hang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:28
CPC Classifications
C; C03; C03C; C03C8/00; C03C8/14; C03C8/16; C03C8/02; H; H01; H01B; H01B1/00; H01B1/14; H01B1/16
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
104 words
A screen-printable thick film paste composition suitable for forming conductive patterns on a rigid substrate comprising: (a) finely divided particles of a lead-free glass composition having a softening point log (eta)=7.6 poise from 400° C.-650° C., a log (eta) specific viscosity in a range from 2 at 500° C. to 5 at 700° C. and consisting essentially of, by weight 65-95% Bi 2 O 3 , 2-15% SiO 2 , 0.1-9% B 2 O 3 , 0-5% Al 2 O 3 , 0-5% CaO, and 0-20% ZnO; (b) electrically conductive particles; and all of (a) and (b) being dispersed in (c) an organic medium.
Claim 2
Dependent Claim
104 words
A screen-printable thick film paste composition suitable for forming conductive patterns on a rigid substrate comprising: (a) finely divided particles of a lead-free glass composition having a softening point log (eta)=7.6 poise from 400° C.-650° C., a log (eta) specific viscosity in a range from 2 at 500° C. to 5 at 700° C. and consisting essentially of, by weight 65-95% Bi 2 O 3 , 2-15% SiO 2 , 0.1-9% B 2 O 3 , 0-5% Al 2 O 3 , 0-5% CaO, and 0-20% ZnO; (b) electrically conductive particles; and all of (a) and (b) being dispersed in (c) an organic medium.
Claim 3
Dependent Claim
14 words
The paste composition of claim 1 wherein the firing temperature is from 580°-680° C.
Claim 4
Dependent Claim
12 words
The paste composition of claim 1 further comprising an alkali fluorophosphate glass.
Claim 5
Dependent Claim
25 words
The paste composition of claim 1 wherein log (eta) specific viscosity is in a range from 2 at 500° C. to 4 at 680° C.
Claim 6
Dependent Claim
30 words
The paste composition of claim 1 further comprising up to 1% of a sintering inhibitor selected from the group consisting of precursors and oxides of ruthenium, rhodium, and mixtures thereof.
Claim 7
Dependent Claim
19 words
The paste composition of claim 1 wherein the electrically conductive particles are flake Ag, powdered Ag or mixtures thereof.
Claim 8
Dependent Claim
41 words
The paste composition of claim 1 wherein the glass composition consists essentially of by weight 68-75% Bi 2 O 3 , 5-15% SiO 2 , 5-9% B 2 O 3 , 0.8-5% Al 2 O 3 , 0.3-3% CaO, 9-15% ZnO.
Claim 9
Dependent Claim
46 words
The paste composition of claim 3 wherein the log (eta) specific viscosity is in a range from 2 at 500° C. to 4 at 680° C. for the alkali fluorophosphate glass or volumetrically computed average log (eta) for a mixture of lead-free and alkali fluorophosphate glasses.
Claim 10
Dependent Claim
13 words
The paste composition of claim 5 wherein the sintering inhibitor is rhodium resinate.
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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) | 1998-01-02 | 1998-07-04 | 1999-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-01-02 | 2002-07-04 | 2003-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-01-02 | 2006-07-04 | 2007-01-03 | $7700.00 | Window Closed / Lapsed |