Spring-Loaded Probe Tip for High-Frequency Signal Fidelity

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Solution Overview

Problem

Current probe tips for high-speed serial busses, such as DDR2 and DDR4 SDRAM, and PCIe, face challenges with precise electrical probing due to varying test point geometries and accessibility, requiring compliance and quick debugging capabilities that existing semi-permanent solutions like soldering or epoxying fail to provide, leading to potential device damage, long setup times, and variability in signal fidelity.

Innovation Solution

The proposed solution involves a differential probe tip with a compliance member and a spring mechanism, including a barrel component and a resistive/impedance element, allowing for precise, height-compliant, and light-pressure contact with a device under test, utilizing a round rod resistor with a resistive coating and a tip component for fine-grain electrical connectivity, which reduces device loading and enhances signal fidelity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If soldering or epoxying is used to create semi-permanent probe contacts, then contact stability is improved, but device complexity increases and setup time increases

Engineering Contradiction:
Improvecontact stabilityVSAvoidsetup complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the contact creation process from permanent methods (soldering/epoxying) and implements it through a reusable probe tip with an integrated spring mechanism. The spring-loaded contact point is extracted as a standalone component that can be repeatedly engaged and disengaged without permanent attachment, eliminating the need for soldering or epoxying while maintaining stable electrical contact.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The spring mechanism in the probe tip automatically applies contact force to the test point without requiring external assistance or complex positioning. The spring self-regulates the contact pressure and maintains reliable electrical connection through its elastic properties, making the contact process self-service and eliminating the need for skilled manual soldering operations.

Inventive Principle:
Principle #25Self-service

2Reliability

If soldering or epoxying is used to create semi-permanent probe contacts, then contact stability is improved, but loss of time increases

Engineering Contradiction:
Improvecontact stabilityVSAvoidsetup time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The probe tip is pre-configured with a spring mechanism that is already loaded and ready to make contact. The spring is pre-compressed during manufacturing, so when the probe tip is brought to the test point, contact is immediately established without requiring time-consuming soldering or epoxying operations. The preliminary preparation of the spring mechanism enables rapid deployment.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The probe tip uses a replaceable, cost-effective spring-loaded contact mechanism rather than permanent soldered connections. When the spring mechanism wears out after repeated use, the entire probe tip can be quickly replaced as a single unit, which is faster and more economical than repairing or re-soldering individual contact points. This disposable approach reduces setup time for replacements.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If soldering or epoxying is used to create semi-permanent probe contacts, then contact stability is improved, but object-affected harmful factors increase

Engineering Contradiction:
Improvecontact stabilityVSAvoiddevice damage risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The spring mechanism in the probe tip provides beforehand cushioning by using elastic deformation to absorb impact forces during contact establishment. When the probe tip contacts the test point, the spring compresses to cushion the impact, preventing mechanical damage to both the probe and the device under test. This prior cushioning through elastic compliance eliminates the need for forceful soldering operations that could damage sensitive test points.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Ease of operation

If probe tips require compliance for accessing test points at various orientations, then ease of operation is improved, but device complexity increases

Engineering Contradiction:
Improveprobe positioning flexibilityVSAvoidprobe structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The probe tip incorporates a dynamic spring mechanism that automatically adjusts to different test point orientations and positions. The spring-loaded contact point can compliancely adapt to vertical, horizontal, or angled test points without requiring complex mechanical adjustment mechanisms. The dynamic elastic properties of the spring provide the necessary compliance while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring mechanism changes its physical parameters (compression distance, contact force) automatically based on the test point orientation and position. When contacting test points at different orientations, the spring compresses to different extents, dynamically adjusting the contact parameters to maintain reliable electrical connection. This parameter adaptation occurs automatically without requiring complex mechanical reconfiguration.

Inventive Principle:
Principle #35Parameter changes

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

This configuration enables high-speed signal acquisition with superior visibility and intuitive operation, reducing setup times and maintaining signal fidelity, particularly in high-frequency signals, while minimizing device damage and the need for frequent replacements.

Implementation Method 1

a spring mechanism positioned within the barrel component and configured to act on the plunger component responsive to the plunger component sliding in an inward direction inside the barrel component

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a resistive/impedance element configured to be coupled with the force deflecting assembly, wherein the resistive/impedance element is a round rod resistor

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentEP3056912B1High frequency probe tip
Publication Date: 2021.04.07 TEKTRONIX INC
  • EP3056912B1 patent drawingFigure 1
  • EP3056912B1 patent drawingFigure 2
  • EP3056912B1 patent drawingFigure 3

AI summary

A test probe tip (100) can include a compliance member or force deflecting assembly and a tip component (108). The compliance member or force deflecting assembly can include a plunger component (104) and a barrel component (102) to receive the plunger component, wherein the plunger component is configured to slide axially inside the barrel component. The test probe tip (100) can also include a spring mechanism within the barrel component to act on the plunger component, and a resistive/impedance element (106), e.g., a round rod resistor, coupled with the plunger component (104) at one end and with the tip component (108) at the opposite end.