US3766470A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for testing the integrity of a thru-hole plating in circuit board workpieces or the like by measuring the effective thickness thereof
Assignee: VEECO INSTRUMENTS ACQUISITION CORP
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Filing: 1971-05-24
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Granted: 1973-10-16
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Expires: 1991-05-24
Abstract
Abstract An apparatus is provided for testing the integrity of thru-hole plating in printed circuit boards by measuring the effective thickness thereof. A printed circuit board is adapted to be positioned on a work surface of the apparatus with the plated thru-hole to be measured disposed at an operating location. A spaced pair of electrode probe are displaced downwardly along a predetermined path into engagement with the top defining edges of the plated thru-hole. A second spaced pair of electrode probe elements engage the bottom defining edges of the thru-hole whereby a predetermined magnitude of constant current can be passed through one of the upper electrode probes, the plating and one of the lower electrode probes and the voltage drop developed thereby across the thru-hole plating measured by the other set of upper and lower electrode probe elements. The upper and lower electrode probes are suitably contoured to establish essentially point contact with the surfaces of the thru-hole plating whereby accurate and reproducible readings can be obtained.
Inventors
- 👤 W Hay
- 👤 R Jensen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:34
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/28; G01R31/2801; G01R31/2805
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
231 words
An apparatus for measuring the conductivity of a plated coating on a thru-hole in a circuit board workpiece comprising a planar supporting platform defining a measurement station and adapted to support a circuit board workpiece having a thru-hole with a plated coating disposed in overlying relation therewith, a first pair of independently resiliently mounted displaceable electrode elements disposEd in closely spaced positional relation beneath said platform and each adapted to engage a marginal defining edge of the bottom of said thru-hole disposed at said measurement station, a second closely spaced pair of displaceable electrode elements selectively disposed in longitudinal coalignment with said electrode elements of said first pair thereof above said platform and each adapted to engage a marginal defining edge of the top of said thru-hole, means for lineally displacing said second pair of electrode elements intermediate a retracted position remote from said first pair of electrode elements and an advanced position in operative engaged relationship with the upwardly disposed defining edge of said plated thru-hole on an interposed workpiece supported by said platform, and means for independently resiliently mounting said second pair of electrode elements when in advanced position so that the plated marginal defining edges of the thru-hole in the interposed workpiece engaged by said first and second pairs of electrode elements are subjected to a substantially uniform and reproduceable magnitude of compressive force during the measurement operation.
Claim 2
Independent Claim
231 words
An apparatus for measuring the conductivity of a plated coating on a thru-hole in a circuit board workpiece comprising a planar supporting platform defining a measurement station and adapted to support a circuit board workpiece having a thru-hole with a plated coating disposed in overlying relation therewith, a first pair of independently resiliently mounted displaceable electrode elements disposEd in closely spaced positional relation beneath said platform and each adapted to engage a marginal defining edge of the bottom of said thru-hole disposed at said measurement station, a second closely spaced pair of displaceable electrode elements selectively disposed in longitudinal coalignment with said electrode elements of said first pair thereof above said platform and each adapted to engage a marginal defining edge of the top of said thru-hole, means for lineally displacing said second pair of electrode elements intermediate a retracted position remote from said first pair of electrode elements and an advanced position in operative engaged relationship with the upwardly disposed defining edge of said plated thru-hole on an interposed workpiece supported by said platform, and means for independently resiliently mounting said second pair of electrode elements when in advanced position so that the plated marginal defining edges of the thru-hole in the interposed workpiece engaged by said first and second pairs of electrode elements are subjected to a substantially uniform and reproduceable magnitude of compressive force during the measurement operation.
Claim 3
Dependent Claim
190 words
A measuring apparatus according to claim 1 wherein each electrode element of said second pair of electrode elements includes cylindrical probe means having terminal contact segments thereon, each of said contact segments having contoured surface means for selectively engaging the inner edge of the top surface of the thru-hole plating being measured and defining, in a plane parallel to a plane defined by the axes of said cylindrical probes, an acute angle with the surface of an interposed workpiece and having, in a plane perpendicular to said first mentioned plane, a circular contour, and wherein each electrode element of said first pair of electrode elements includes terminal contact segments having contoured surface means defining, in a plane parallel to the plane defined by said axes, an acute angle with the interposed workpiece and having, in a plane perpendicular to said plane, a circular contour whereby when said first and second pairs of electrode elements are brought into engagement with the inner edges of the top and bottom surfaces of the thru-hole plating, each of said first and second contoured surface means will establish essentially point contact with the thru-hole plating.
Claim 4
Dependent Claim
63 words
A measuring apparatus according to claim 3 wherein said terminal contact segments of said first and second pair of electrode elements define, in the plane parallel to the plane defined by the axes of the cylindrical probes, symmetrical V-shaped and inverted V-shaped terminal portions respectively and wherein the imaginary bottom and top of the V and inverted V configurations respectively are vertically aligned.
Claim 5
Dependent Claim
32 words
A measuring apparatus according to claim 2 wherein the lowermost points of curvature transversely across the contoured surface means of each of said first and second electrode elements define a vertical plane.
Claim 6
Dependent Claim
50 words
A measuring apparatus according to claim 2 wherein the points of contact between said second electrode elements and the top surface of a thru-hole plating in a horizontally disposed workpiece are vertically above the points of contact between said first electrode elements and the bottom surface of said thru-hole plating.
Claim 7
Dependent Claim
27 words
A measuring apparatus according to claim 1 wherein said lineally displacing means includes means for independently varying the retracted position of each of said second electrode elements.
Claim 8
Dependent Claim
28 words
A measuring apparatus according to claim 6 further comprising means for biasing said first pair of electrode elements upwardly to extend beyond the surface of said supporting means.
Claim 9
Dependent Claim
37 words
A measuring apparatus according to claim 7 further comprising means for preventing the striking of a workpiece against said first electrode elements when the workpiece is introduced into interposed relation between said first and second elEctrode elements.
Claim 10
Dependent Claim
43 words
A measuring apparatus according to claim 8 wherein said apparatus further comprises magnification means and illuminating means disposed adjacent to said measuring station for facilitating manual positioning of a plated thru-hole in a workpiece in the path of advance of said electrode elements.
Claim 11
Dependent Claim
124 words
An apparatus for measuring the integrity and thickness of a thru-hole plating according to claim 1, further comprising an elongated housing, a first spaced pair of individually shielded electrical leads joined to one set of said first and second electrode elements and extending longitudinally of said housing in parallel relation to each other and a second spaced pair of shielded electrical leads joined to the other set of said first and second electrode elements and extending longitudinally of said housing in parallel relation to each other, said first and second spaced pairs of shielded electrical leads being so positioned that a plane containing said first pair of electrical leads will be disposed substantially perpendicular to a plane containing said second pair of electrical leads.
Claim 12
Dependent Claim
90 words
An apparatus for measuring the integrity and thickness of a thru-hole plating according to claim 10 further comprising a readout unit for supplying a constant electrical current to one set of first and second electrode elements and means for measuring the voltage drop across said other set of first and second electrode elements, said means including a high gain input circuit feeding a low noise amplifier arranged for common mode operation and indicating means responsive to the output of said amplifier for visually displaying the magnitude of said voltage drop.
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) | 1976-10-15 | 1977-04-16 | 1977-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-15 | 1981-04-16 | 1981-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-15 | 1985-04-16 | 1985-10-16 | $7700.00 | Window Closed / Lapsed |