Patent US4522067A successfully refreshed from Google Patents.
US4522067A
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Thin-film strain gauge
Assignee: Robert Bosch GmbH
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Filing: 1981-12-18
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Granted: 1985-06-11
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Expires: 2001-12-18
Abstract
Abstract A thin-film strain gauge and a method for producing it are proposed; the strain gauge is advantageously capable of integration into a thin-film circuit. The strain gauge comprises an elastically deformable spring element in combination with at least one elongation-sensitive resistor. The resistor disposition (R1-R4), the low-impedance connections (L11-L42) between the various resistance regions and the associated connection tracks (L5-L8) are applied in a vacuum process, preferably by cathode sputtering. The low-impedance connections (L11-L42) and the connection tracks (L5-L8) are of material which, although different from the material making up the actual resistance region, still has approximately the same temperature coefficient of resistance, so as to preclude errors caused by temperature.
Inventors
- 👤 Kurt Burger
- 👤 Heiko Gruner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:38
CPC Classifications
G; G01; G01L; G01L1/00; G01L1/20; G01L1/22; G01L1/2287; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49099; Y10T29/49103
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
223 words
A temperature-compensated thin-film strain gauge, particularly a precision thin-film strain gauge capable of integration into a thin-film circuit, for measuring force, pressure, displacement, weight, or acceleration, having an elastically deformable spring device (10, S) in combination with at least one elongation-sensitive resistor element, having at least one deflectable resistance region (R1, R3) and one substantially non-deflecting resistance region (R2, R4); at least one low-impedance connection element (L11-L42) connecting at least said resistance regions (R1, R3; R2, R4); and connection tracks (L5-L8), wherein, to simplify production and facilitate integration of the gauge in a larger thin-film circuit, at least one of: the resistor element disposition (R1, R4); the low-impedance connections (L11-L42) between the various resistance regions; and associated connection tracks (L5-L8) are applied by means of at least one of thermal vapor deposition and cathode sputtering; and wherein, to prevent temperature fluctuations from giving rise to erroneous strain change measurements, the temperature coefficients of resistance (TCR's) of the materials used for the elongation-sensitive resistor element (R1-R4) and at least one of the low-impedance connections (L11-L42) and the connection tracks (L5-l8) are of the same order of magnitude; and wherein, to prevent loss of measurement signal strength, at least one of: the low-impedance connections (L11-L42); and the connection tracks (L5-L8) are of material which is different from the material of the resistance element regions (R1-R4).
Claim 2
Dependent Claim
223 words
A temperature-compensated thin-film strain gauge, particularly a precision thin-film strain gauge capable of integration into a thin-film circuit, for measuring force, pressure, displacement, weight, or acceleration, having an elastically deformable spring device (10, S) in combination with at least one elongation-sensitive resistor element, having at least one deflectable resistance region (R1, R3) and one substantially non-deflecting resistance region (R2, R4); at least one low-impedance connection element (L11-L42) connecting at least said resistance regions (R1, R3; R2, R4); and connection tracks (L5-L8), wherein, to simplify production and facilitate integration of the gauge in a larger thin-film circuit, at least one of: the resistor element disposition (R1, R4); the low-impedance connections (L11-L42) between the various resistance regions; and associated connection tracks (L5-L8) are applied by means of at least one of thermal vapor deposition and cathode sputtering; and wherein, to prevent temperature fluctuations from giving rise to erroneous strain change measurements, the temperature coefficients of resistance (TCR's) of the materials used for the elongation-sensitive resistor element (R1-R4) and at least one of the low-impedance connections (L11-L42) and the connection tracks (L5-l8) are of the same order of magnitude; and wherein, to prevent loss of measurement signal strength, at least one of: the low-impedance connections (L11-L42); and the connection tracks (L5-L8) are of material which is different from the material of the resistance element regions (R1-R4).
Claim 3
Dependent Claim
25 words
Strain gauge according to claim 1, wherein the at least one elongation-sensitive resistor element comprises four elongation-sensitive resistors (R1, R4) combined into a Wheatstone bridge.
Claim 4
Dependent Claim
24 words
Strain gauge according to claim 1, wherein at least one of: the low-impedance connections (L11-L42); the connection tracks (L5-L8) comprise constantan doped with nitrogen.
Claim 5
Dependent Claim
25 words
Strain gauge according to claim 3, wherein the at least one elongation-sensitive resistor element comprises four elongation-sensitive resistors (R1, R4) combined into a Wheatstone bridge.
Claim 6
Dependent Claim
36 words
Strain gauge according to claim 1, wherein the at least one elongation-sensitive resistor element (L1-L4) comprises tantalum nitride (Ta 2 N, TaN); or tantalum oxynitride (TaO x N y ); or tantalum nitride and tantalum oxynitride.
Claim 7
Dependent Claim
25 words
Strain gauge according to claim 5, wherein the at least one elongation-sensitive resistor element comprises four elongation-sensitive resistors (R1, R4) combined into a Wheatsone bridge.
Claim 8
Dependent Claim
41 words
Strain gauge according to claim 1, wherein the spring device (10) is an elastically deformable device; a thin organic foil is adhesively connected to said spring device; and the elongation sensitive resistor element (R1-R4) is applied on the thin organic foil.
Claim 9
Dependent Claim
25 words
Strain gauge according to claim 7, wherein the at least one elongation-sensitive resistor element comprises four elongation-sensitive resistors (R1, R4) combined into a Wheatstone bridge.
Claim 10
Dependent Claim
32 words
Strain gauge according to claim 1, further including an insulation layer (I) interposed between the spring device (10S) and the elongation-sensitive resistor element (R1, R4) vapor-deposited or sputtered on the insulation layer.
Claim 11
Dependent Claim
25 words
Strain gauge according to claim 9, wherein the at least one elongation-sensitive resistor element comprises four elongation-sensitive resistors (R1, R4) combined into a Wheatstone bridge.
Claim 12
Dependent Claim
59 words
Strain gauge according to claim 1, wherein said elongation-sensitive resistor elements (R1, R4) are connected in a Wheatstone bridge configuration, located in a rectangular disposition having two elongatable resistance regions (R1, R3) and two non-elongatable resistance regions (R2, R4), said resistance regions being applied onto the spring device (10); and wherein the spring device is deflectable at one end.
Claim 13
Dependent Claim
55 words
Strain gauge according to claim 11, wherein at least one of: the low-impedance connections (L11-L42); the connection tracks (L5-L8) comprise constantan doped with nitrogen; and wherein the at least one elongation-sensitive resistor element (L1-L4) comprises tantalum nitride (Ta 2 N, TaN); or tantalum oxynitride (TaO x N y ); or tantalum nitride and tantalum oxynitride.
Claim 14
Dependent Claim
64 words
Strain gauge according to claim 1, wherein said elongation-resistance resistance element (R1, R4) is connected in a Wheatstone bridge configuration having two resistance regions (R1, R3) shaped to be approximately semicircular, and being tangentially elongatable, and two resistance regions (R2, R4) which are radially elongatable, and approximately U-shaped; and the spring device comprises a round membrane on which said elongation-sensitive resistance element is applied.
Claim 15
Dependent Claim
38 words
Strain gauge according to claim 1, further including a poreless thin high-impedance glass insulation layer (I) being applied to the spring device (S); and wherein the elongation-sensitive resistance element (R1, R4) is applied over the glass insulation layer.
Claim 16
Dependent Claim
16 words
Strain gauge according to claim 14, wherein the spring device comprises a copper-beryllium (CuBe) spring plate.
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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) | 1988-06-10 | 1988-12-10 | 1989-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-10 | 1992-12-10 | 1993-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-10 | 1996-12-10 | 1997-06-11 | $7700.00 | Window Closed / Lapsed |