US3624496A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for swept-frequency impedance measurements of welds
Assignee: National Aeronautics and Space Administration
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Filing: 1969-12-31
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Granted: 1971-11-30
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Expires: 1989-12-31
Abstract
Abstract A method and apparatus for testing integrated circuit microtab welds which includes preparing a set of reference signatures for a set of welds of known characteristics and then comparing a signature obtained from a tested weld to these reference signatures to evaluate the integrity of the tested weld. The reference and test signatures are obtained by passing highfrequency electric signals through the various welded structures and sweeping the frequency thereof through the resonance frequencies of the welds. In-phase variations and quadrature variations produced in the electric signals passed through the welds are measured and compared against the reference signatures in order to qualitatively evaluate the integrity of the tested weld.
Inventors
- 👤 Lester Feinstein
- 👤 Ronald J Hruby
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 04:24
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/28; G01R31/302
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
131 words
Nondestructive test apparatus for inspecting and evaluating the integrity of a weld joining first and second metallic pieces comprising: signal source means for generating across first and second terminals an alternating signal the frequency of which is swept over a predetermined range of frequencies; a first probe coupled to said first metallic piece on one side of said weld; means for connecting said first probe to said first terminal; a second probe coupled to said second metallic piece on the opposite side of said weld; a reactive waveform sensing element; a resistive waveform sensing element; said reactive and resistive elements being connected in series between said second terminal and said second probe; and function synthesizing means connected to said reactive and resistive elements for providing graphic signatures of the weld characteristics.
Claim 2
Dependent Claim
131 words
Nondestructive test apparatus for inspecting and evaluating the integrity of a weld joining first and second metallic pieces comprising: signal source means for generating across first and second terminals an alternating signal the frequency of which is swept over a predetermined range of frequencies; a first probe coupled to said first metallic piece on one side of said weld; means for connecting said first probe to said first terminal; a second probe coupled to said second metallic piece on the opposite side of said weld; a reactive waveform sensing element; a resistive waveform sensing element; said reactive and resistive elements being connected in series between said second terminal and said second probe; and function synthesizing means connected to said reactive and resistive elements for providing graphic signatures of the weld characteristics.
Claim 3
Dependent Claim
37 words
Nondestructive test apparatus as recited in claim 1 wherein said first and second probes each comprise a capacitive probe so as to eliminate the introduction of any ohmic contact resistance between said probes and said metallic pieces.
Claim 4
Dependent Claim
39 words
Nondestructive test apparatus as recited in claim 1 wherein said first and second probes each comprise an electrode and a dielectric, and each of said dielectrics is sandwiched between one of said metallic pieces and one of said electrodes.
Claim 5
Dependent Claim
32 words
Nondestructive test apparatus as recited in claim 1 wherein said first and second probes each comprise a capacitive probe having a reactance which is small compared to the impedance of said weld.
Claim 6
Dependent Claim
35 words
Nondestructive test apparatus as recited in claim 2 wherein said function synthesizing means includes a quadrature function synthesizer responsive to said reactive sensing element and an in-phase function synthesizer responsive to said resistive sensing element.
Claim 7
Dependent Claim
28 words
Nondestructive test apparatus as claimed in claim 5 wherein said quadrature synthesizer and said in-phase synthesizer each comprise a multiplier, a filter and means for displaying a waveform.
Claim 8
Dependent Claim
35 words
A nondestructive test apparatus as claimed in claim 6 wherein said signal from said signal source is fed to each of said multipliers, and each filter is coupled between its respective multiplier and displaying means.
Claim 9
Dependent Claim
34 words
A nondestructive test apparatus as claimed in claim 7 wherein said filters are of the low-pass variety having a cutoff frequency between the highest frequency swept by the signal source and twice that frequency.
Claim 10
Dependent Claim
79 words
A nondestructive test method for evaluating the integrity of a weld comprising the steps of: passing a time-varying electric signal through said weld; sweeping the frequency of said signal over a predetermined range of frequencies; sensing the in-phase variations produced in said time-varying signal by said weld; sensing the quadrature variations produced in said time-varying signal by said weld; providing a graphical representation of each of said variations, said graphical representations being indicative of the integrity of said weld.
Claim 11
Dependent Claim
79 words
A nondestructive test method for evaluating the integrity of a weld comprising the steps of: passing a time-varying electric signal through said weld; sweeping the frequency of said signal over a predetermined range of frequencies; sensing the in-phase variations produced in said time-varying signal by said weld; sensing the quadrature variations produced in said time-varying signal by said weld; providing a graphical representation of each of said variations, said graphical representations being indicative of the integrity of said weld.
Claim 12
Dependent Claim
32 words
A nondestructive testing method as recited in claim 9 and further including the step of comparing said graphical representations with a set of reference representations to qualitatively evaluate the weld being tested.
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) | 1974-11-29 | 1975-05-31 | 1975-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-29 | 1979-05-31 | 1979-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-29 | 1983-05-31 | 1983-11-30 | $7700.00 | Window Closed / Lapsed |