US4287766A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Inspection of solder joints by acoustic impedance
Assignee: Battelle Memorial Institute Inc
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Filing: 1979-09-26
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Granted: 1981-09-08
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Expires: 1999-09-26
Abstract
Abstract A method for detection of unacceptable solder joints, especially solder pads on printed circuit boards (PCBs), by means of the application of acoustic vibrations over a range of frequencies to the solder joint and observation of the acoustic impedance of the joint as reflected back through the driver to the acoustic generator or through an acoustic detector near the generator to electrical detecting apparatus.
Inventors
- 👤 Dale Ensminger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:29
CPC Classifications
G; G01; G01H; G01H15/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
105 words
A method for qualitatively inspecting the integrity of a solder joint joining first and second conductors comprising (a) applying acoustic vibrations to the solder joint over a range of frequencies which includes at least one natural resonant frequency of the solder joint, (b) receiving the acoustic vibrations, as modulated thereby, from the solder joint with a receiving transducer converting acoustic vibrations into electrical signals, (c) observing the spectral response of the receiving transducer, and (d) comparing the spectral response of the receiving transducer with previously determined spectral responses characteristic of either unacceptable or acceptable solder bonds whereby to determine the acceptability of the solder bond.
Claim 2
Independent Claim
105 words
A method for qualitatively inspecting the integrity of a solder joint joining first and second conductors comprising (a) applying acoustic vibrations to the solder joint over a range of frequencies which includes at least one natural resonant frequency of the solder joint, (b) receiving the acoustic vibrations, as modulated thereby, from the solder joint with a receiving transducer converting acoustic vibrations into electrical signals, (c) observing the spectral response of the receiving transducer, and (d) comparing the spectral response of the receiving transducer with previously determined spectral responses characteristic of either unacceptable or acceptable solder bonds whereby to determine the acceptability of the solder bond.
Claim 3
Dependent Claim
18 words
The method of claim 1 wherein the range of frequencies falls between about 20 hz and 1 Mhz.
Claim 4
Dependent Claim
20 words
The method of claim 2 wherein the acoustic vibrations are swept through a frequency range of about 150 khz-650 khz.
Claim 5
Dependent Claim
21 words
The method of claim 1 wherein the range of frequencies includes at least two natural resonant frequencies of the solder joint.
Claim 6
Dependent Claim
26 words
The method of claim 1 wherein the acoustic vibrations are applied to the first conductor or the solder joint and are received from the second conductor.
Claim 7
Dependent Claim
30 words
The method of claim 1 wherein the acoustic vibrations are applied to the first conductor or the solder joint and are received from the first conductor or the solder joint.
Claim 8
Dependent Claim
18 words
The method of claim 6 wherein the acoustic vibrations are both applied and received by the receiving transducer.
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) | 1984-09-07 | 1985-03-09 | 1985-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-07 | 1989-03-09 | 1989-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-07 | 1993-03-09 | 1993-09-08 | $7700.00 | Window Closed / Lapsed |