Spring Probe Contact Ring for Low Resistance
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Solution Overview
Problem
Conventional spring-loaded electrical contact probes experience poor electrical performance due to high internal contact resistance and mechanical wear, especially when the device under test pushes directly on the plunger, leading to compromised reliability and pointing accuracy.
Innovation Solution
Incorporating one or more contact rings in electrical contact with the plunger tail to ensure consistent electrical contact and improve pointing accuracy, with the contact rings being made of conductive materials and designed to maintain contact with the barrel inner surface, even in dirty environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bias cut is used on the plunger tail to improve contact force, then electrical performance is improved, but friction increases causing mechanical wear and reduced reliability
Solution Approach 1:
A contact ring is introduced as an intermediary component between the plunger tail and the spring. The contact ring is biased by the spring to maintain consistent electrical contact with the plunger, providing a low-resistance electrical path without requiring a bias cut on the plunger tail. This eliminates the friction and mechanical wear associated with bias cuts while maintaining reliable electrical performance.
2Reliability
If a bias cut is used on the plunger tail to improve contact force, then contact resistance is reduced, but pointing accuracy deteriorates due to plunger displacement
Solution Approach 1:
The contact ring serves as a mediator that provides the necessary biasing force for electrical contact without displacing the plunger. The spring biases the contact ring against the plunger tail, ensuring low contact resistance and consistent electrical contact while allowing the plunger tip to remain centered and maintain accurate pointing.
3Force
If the device under test pushes directly on the plunger, then mechanical force is transmitted, but electrical performance is compromised due to high internal contact resistance
Solution Approach 1:
The contact ring acts as an intermediary electrical conductor between the plunger and the spring. When the device under test pushes on the plunger, the contact ring maintains consistent electrical contact with the plunger tail, providing a low-resistance path for current flow independent of the mechanical force direction.
Solution Approach 2:
The contact ring is designed with material and geometric parameters optimized for electrical conduction. By changing the contact interface from a biased plunger tail to a contact ring with optimized conductivity and contact surface area, the electrical performance is improved while maintaining mechanical force transmission capabilities.
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 solution significantly reduces internal contact resistance, enhances electrical performance, and maintains pointing accuracy by ensuring a consistent and clean contact between the plunger and barrel, thereby extending the probe's life expectancy and reliability.
Implementation Method 1
a barrel containing a movable plunger and a spring, which exerts a force against the tail of the plunger to bias the plunger outwardly from the barrel
Implementation Method 2
one or more contact rings in electrical contact with the tail of the plunger to ensure electrical contact between the plunger and the barrel
Data Source
AI summary
A spring probe having a barrel, plunger, spring and contact ring is provided in which the contact ring provides electrical contact between the plunger and the barrel. Two or more contact rings may be provided to improve the pointing accuracy of the probe.