Low Capacitance Probe Guard Plate Holes Pin Protection
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Solution Overview
Problem
Capacitive testing of socket components is challenging due to the lack of conductive structures within sockets, leading to unreliable detection of test signals and a high risk of damaging pins during the testing process.
Innovation Solution
A low capacitance probe is designed with a guard plate having holes to reduce capacitance between the sense and guard plates, allowing for increased signal coupling and amplification, and spacers are used to ensure proper alignment and prevent contact with pins, thereby enhancing testing accuracy and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional probe with a solid guard plate is used for capacitive testing, then electrical noise shielding is provided, but capacitance between the sense plate and guard plate is high, reducing signal coupling and measurement precision
Solution Approach 1:
The guard plate is designed with an array of holes instead of being solid, creating a porous structure that reduces capacitance between the sense plate and guard plate while still providing electrical noise shielding. This allows the guard plate to maintain its noise-blocking function while minimizing its harmful capacitive effect on signal coupling.
Solution Approach 2:
The probe assembly combines multiple materials and structures - the sense plate, the perforated guard plate, and dielectric material - to create a composite system that balances noise shielding with low capacitance. The combination of conductive materials for shielding and dielectric materials for isolation achieves both protection and signal integrity.
2Measurement precision
If the probe is inserted into the socket cavity to increase signal coupling, then more test signal is coupled to the probe plate, but the risk of contacting and damaging the pins increases substantially
Solution Approach 1:
A compliant member is incorporated into the probe assembly that acts as a cushion or buffer between the probe and the pins. This compliant element deforms under pressure, preventing direct contact between the rigid probe and the fragile pins, thereby protecting them from damage while still allowing sufficient signal coupling.
Solution Approach 2:
The compliant member is a flexible element that can deform to accommodate positioning variations and prevent hard contact. This flexible component maintains the probe's electrical coupling capability while providing mechanical protection to the pins through its ability to yield under pressure.
3Measurement precision
If the conductive surface area of the sense plate is reduced to lower capacitance, then signal coupling is improved, but the probe's ability to detect weak signals may be compromised
Solution Approach 1:
The guard plate is segmented into multiple discrete holes rather than being a continuous solid surface. This segmentation reduces the total conductive area of the guard plate, thereby reducing its capacitance to the sense plate while still maintaining noise shielding through the distributed structure of the holes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The low capacitance probe improves the signal-to-noise ratio and reliability of capacitive testing results, reducing the risk of damaging pins and enabling more accurate detection of electrical connections in socket components.
Implementation Method 1
reducing capacitance between a sense plate and a guard plate of the probe. Reduced capacitance may be achieved through the shape of the guard plate. For example, the guard plate may have a plurality of holes, which reduce the capacitance between the guard and sense plate.
Implementation Method 2
Though the probe plate is separated from those conducting structures, the test signal can capacitively couple to the probe plate.
Data Source
AI summary
An improved system for capacitive testing electrical connections in a low signal environment. The system includes features that increase sensitivity of a capacitive probe. One feature is a spacer positioned to allow the probe to be partially inserted into the component without contacting the pins. The spacer may be a collar on the probe that contacts the housing of the component, contacts the substrate of the circuit assembly, or both. In some other embodiments, the spacer may be a riser extending beyond the surface of the sense plate that contacts the component, a riser portion of the component, or a combination of both. The spacer improves sensitivity by establishing a small gap between a sense plate of the probe and pins under test without risk of damage to the pins. A second feature is a guard plate of the probe with reduced capacitance to a sense plate of the probe. Reducing capacitance also increases the sensitivity of the probe.