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EP0599544A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Capacitive electrode system for detecting open solder joints in printed circuit assemblies

Assignee: HP Inc
•
Filing: 1993-11-18
•
Granted: —
•
Expires: 2013-11-18
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Abstract

Abstract Disclosed is a system that determines whether input and output leads (412) of semiconductor components (410) are present and properly soldered to a printed circuit board. The system includes a signal source (118) which is connected to a wiring trace (814) on the printed circuit board, which is soldered to the lead (412) being tested. A capacitive test probe (206) is placed on top of the component (410) and connected to a capacitance measuring device (122). The signal source (118) signal is capacitively coupled through the lead (412) of the integrated circuit package being tested to the capacitive test probe (206), so if a predetermined capacitance is measured by the capacitance measuring device (122), the lead (412) is connected to the circuit assembly. As the capacitances being measured are small, the capacitive test probe (206) may include an amplifier, a shield or a buffer circuit to reduce stray capacitance.

Inventors

  • 👤 Ronald K. Kerschner
  • 👤 David T. Crook
  • 👤 Lisa M. Kent

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-10 02:36
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/28; G01R31/2801; G01R31/281; G01R31/2812; G01R31/302; G01R31/312

Claims Analysis

Total Claims: 10
Claim 1
Independent Claim 165 words
A test probe (206) for testing an electrical component (410) to determine whether a connector lead (412) of said electrical component (410) is conductively connected to a trace (814) of a printed circuit board, said test probe (206) comprising: conductive plate means (202) for capacitively detecting an electrical field generated by said connector lead (412) of said electrical component whenever said connector lead (412) is conductively connected to said trace (814) producing a test signal; shielding means (204) for providing shielding from electrical noise; and signal amplification means (208) electrically coupled to said conductive plate means (202) for amplifying said test signal to increase the signal to noise ratio of said test signal to said electrical noise, said signal amplification means (208) and said shielding means (204) being disposed in sufficient proximity to said conductive plate means (202) to generate a test signal that has a sufficient signal to noise ratio to determine whether said connector lead (412) is conductively connected to said trace (814).
Claim 2
Dependent Claim 17 words
The test probe (206) of claim 1 wherein said conductive plate means (202) comprises a metal plate.
Claim 3
Dependent Claim 15 words
The test probe (206) of claim 2 wherein said metal plate is made from copper.
Claim 4
Dependent Claim 19 words
The test probe (206) of any of the preceding claims wherein said shielding means (204) is a guard plate.
Claim 5
Dependent Claim 16 words
The test probe (206) of claim 4 wherein said guard plate comprises an electrically conductive material.
Claim 6
Dependent Claim 14 words
The test probe (206) of claim 5 wherein said electrically conductive material comprises copper.
Claim 7
Dependent Claim 21 words
The test probe (206) according to claims 4 or 5 wherein said guard plate substantially surrounds said signal amplification means (208).
Claim 8
Dependent Claim 35 words
The test probe (206) according to claims 4 or 5 wherein said guard plate is located a predetermined distance above said conductive plate means (202) and is substantially parallel to said conductive plate means (202).
Claim 9
Dependent Claim 23 words
The test probe (206) of claim 8 wherein said guard plate and said conductive plate means (202) are separated by a dielectric material.
Claim 10
Dependent Claim 19 words
The test probe (206) of any of the preceding claims wherein said electrical component (410) comprises an integrated circuit.

References Cited (Backward Citations)

EP0177210A1 Cited
GB2179751A Cited
US4918376A Cited
EP0492806A2 Cited
EP0560484A2 Cited

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