Patent US5709927A successfully refreshed from Google Patents.
US5709927A
Expired / Lapsed
US
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Thick film circuit board
Assignee: Murata Manufacturing Co Ltd
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Filing: 1996-03-29
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Granted: 1998-01-20
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Expires: 2016-03-29
Abstract
Abstract A thick film circuit board comprising an insulating substrate; conductor wiring layers of a conductive material containing an oxide and formed on the insulating substrate by printing and firing; a resistance layer of a resistive material having a selected sheet resistance, being chemically reactive with the oxide, and formed between and bridging the conductor wiring layers by printing and firing; and a conductive barrier layer interposed between each of the conductor wiring layers and the resistance layer to prevent chemical reaction between the oxide of the conductor wiring layers and the resistive material of the resistance layer.
Inventors
- 👤 Yoshiyuki Miyase
- 👤 Tohru Nomura
- 👤 Akihiko Naito
- 👤 Takamasa Okumura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 16:27
CPC Classifications
H; H01; H01C; H01C1/00; H01C1/14; H01C1/146; H10; H10D; H10D86/00; H10D86/80; H10D86/85; Y; Y10; Y10S; Y10S428/00; Y10S428/901; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24917; Y10T428/24926
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
104 words
A thick film circuit board comprising: an insulating substrate; conductor wiring layers of a conductive material containing an oxide, the conductor wiring layers being formed on the insulating substrate by printing and firing; a resistance layer of a resistive material having a selected sheet resistance, being chemically reactive with the oxide, and formed between the conductor wiring layers and bridging the conductor wiring layers by printing and firing; and a barrier layer interposed between each of the conductor wiring layers and the resistance layer to prevent chemical reaction between the oxide in the conductor wiring layers and the resistive material in the resistance layer.
Claim 2
Dependent Claim
104 words
A thick film circuit board comprising: an insulating substrate; conductor wiring layers of a conductive material containing an oxide, the conductor wiring layers being formed on the insulating substrate by printing and firing; a resistance layer of a resistive material having a selected sheet resistance, being chemically reactive with the oxide, and formed between the conductor wiring layers and bridging the conductor wiring layers by printing and firing; and a barrier layer interposed between each of the conductor wiring layers and the resistance layer to prevent chemical reaction between the oxide in the conductor wiring layers and the resistive material in the resistance layer.
Claim 3
Dependent Claim
70 words
A thick film circuit board according to claim 1, wherein the chemical reaction prevented by the barrier layer is a reduction of the oxide in the conductor wiring layers by the resistive material in the resistance layer, and wherein the barrier layer covers the conductor wiring layers at least in a portion where a peripheral portion of the resistance layer is engaged with a portion of the conductor wiring layers.
Claim 4
Dependent Claim
41 words
A thick film circuit board according to claim 2, wherein the barrier layer is a conductive barrier layer formed of a second resistive material having a sheet resistance different from a sheet resistance of the resistive material in the resistance layer.
Claim 5
Dependent Claim
30 words
A thick film circuit board according to claim 3, wherein the second resistive material in the barrier layer is a resistive material forming resistors in the thick film circuit board.
Claim 6
Dependent Claim
55 words
A thick film circuit board according to claim 4, wherein the insulating substrate is a ceramic substrate, the conductor wiring layers are copper conductor wiring layers, and the resistive material in the resistance layer having the selected sheet resistance and the second resistive material of in the barrier layer are a lanthanum boride-based resistive material.
Claim 7
Dependent Claim
47 words
A thick film circuit board according to claim 5, wherein the resistive material in the resistance layer having the selected sheet resistance contains a larger amount of a lanthanum boride-based conductor component and has a lower sheet resistance than the second resistive material forming the barrier layer.
Claim 8
Dependent Claim
49 words
A thick film circuit board according to claim 6, wherein the resistive material in the resistance layer having the selected sheet resistance has a sheet resistance of from 10Ω/square to 50Ω/square and the second resistive material forming the barrier layer has a sheet resistance between 60Ω/square and 5 kΩ/square.
Claim 9
Dependent Claim
71 words
A thick film circuit board according to claim 1, wherein the chemical reaction prevented by the banner layer is a chemical reaction producing an insulating material, the chemical reaction occurring between the resistive material in the resistance layer and the oxide in the conductor wiring layers, and wherein the barrier layer is disposed over a part of a contacting surface between each of the conductor wiring layers and the resistance layer.
Claim 10
Dependent Claim
41 words
A thick film circuit board according to claim 8, wherein the barrier layer is a conductive barrier layer formed of a second resistive material having a sheet resistance different from the sheet resistance of the resistive material in the resistance layer.
Claim 11
Dependent Claim
30 words
A thick film circuit board according to claim 9, wherein the second resistance material in the barrier layer is a resistive material forming resistors in the thick film circuit board.
Claim 12
Dependent Claim
54 words
A thick film circuit board according to claim 10, wherein the insulating substrate is a ceramic substrate, the conductor wiring layers are copper conductor wiring layers, and the resistive material in the resistance layer having the selected sheet resistance and the second resistive material in the barrier layer are a lanthanum boride-based resistive material.
Claim 13
Dependent Claim
77 words
A thick film circuit board according to claim 11, wherein the resistive material of the resistance layer having the selected sheet resistance is chemically reactive with the copper conductor wiring layers and has a higher sheet resistance than the sheet resistance of the barrier layer, and the second resistive material forming the barrier later is chemically non-reactive with the copper conductor wiring layers and has a lower sheet resistance than the sheet resistance of the resistance layer.
Claim 14
Dependent Claim
50 words
A thick film circuit board according to claim 12, wherein the resistive material of the resistance layer having the selected sheet resistance has a sheet resistance between 5 kΩ/square and 10 kΩ/square and the second resistive material forming the barrier layer has a sheet resistance between 60Ω/square and 5 kΩ/square.
Claim 15
Dependent Claim
35 words
A thick film circuit board according to claim 1, wherein the thick film circuit board is used as a part of a build-in IC igniter of an ignition coil mounted on an internal combustion engine.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-01-19 | 2001-07-21 | 2002-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-01-19 | 2005-07-21 | 2006-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-01-19 | 2009-07-21 | 2010-01-20 | $7700.00 | Window Closed / Lapsed |