Flying Probe Tester Contact Mechanism for Board Deformation

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Solution Overview

Problem

Conventional flying probe electronic board testers face limitations due to the mechanical load exerted by fixed connectors, which can cause board deformations and restrict the number of contacts, and alternative solutions like needle beds are costly or unsuitable for fast, on-line applications.

Innovation Solution

A flying probe testing machine with a conveyor system using three pairs of belts to load and unload boards, featuring contacting devices with spring-loaded Pogo pins that interact with side edges of the boards for power supply and diagnostic signals, allowing contact on specific areas without deforming the board and enabling use of flying probes on both sides.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If spring-loaded contact needles are used in fixed connectors, then reliable electrical contact is achieved, but mechanical load causes board deformation and limits the number of contacts

Engineering Contradiction:
Improveelectrical contact reliabilityVSAvoidboard deformation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a compliant substrate as an intermediary between the fixed connector and the board. This compliant substrate deforms elastically under the spring load to accommodate manufacturing tolerances and board variations, preventing direct transmission of mechanical stress to the board while maintaining reliable electrical contact through the contact needles

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the mechanical parameters of the contact system by using spring-loaded contact needles with optimized spring constants and pre-loads. The spring mechanism allows the contact force to be maintained within an optimal range that ensures reliable electrical contact without exceeding the board's deformation threshold, thus resolving the contradiction between contact reliability and board integrity

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If more contact needles are added to fixed connectors, then more diagnostic contacts are available, but board deformation increases due to accumulated mechanical load

Engineering Contradiction:
Improvenumber of contact pointsVSAvoidboard deformation
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The compliant substrate acts as a load-distributing intermediary that spreads the mechanical stress from multiple contact needles across a larger area. This allows the system to accommodate a higher number of contact points without proportionally increasing the deformation risk to the board, as the compliant material absorbs and distributes the accumulated mechanical load

Inventive Principle:
Principle #24Intermediary (Mediator)

3Quantity of substance

If needle bed solution is used for power supply and diagnostic contacts, then contact capacity is increased, but flying probes cannot be used on both sides of the board and fitting costs increase

Engineering Contradiction:
Improvecontact capacityVSAvoidsystem configuration complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent makes the fixed connector universal by designing it to work in conjunction with flying probes on both sides of the board. The compliant substrate and contact needle arrangement can accommodate various probe configurations, allowing the same fixed connector design to support single-sided and double-sided flying probe testing, thereby eliminating the need for separate needle bed solutions and reducing overall system complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the functions of the fixed connector and flying probe system into a unified testing architecture. By integrating the compliant substrate-based fixed connector with dual-sided flying probe capability, the system combines the benefits of high contact capacity with operational flexibility, eliminating the need for separate needle bed installations and reducing fitting costs

Inventive Principle:
Principle #5Merging (Combining)

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 solution allows for efficient testing without board deformation, increased contact points, and flexibility in handling different board sizes, while eliminating the drawbacks of conventional fixed connectors and maintaining compatibility with fast, on-line applications.

Implementation Method 1

contacting devices with spring-loaded Pogo pins that interact with side edges of the boards

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3571517B1Flying probe electronic board tester, and test method thereof
Publication Date: 2022.11.09 SPEA
  • EP3571517B1 patent drawingFigure 1
  • EP3571517B1 patent drawingFigure 2
  • EP3571517B1 patent drawingFigure 3

AI summary

Machine (1) with flying probes for testing electronic boards (2) comprising a conveyor (4) for loading / unloading the boards (2) into / from the testing station (3), a plurality of flying probes (9) suitable to interact with predetermined points of each board and a plurality of contacting devices (10) arranged at the sides of the working volume of the flying probes (9) and suitable to cooperate with contact areas (11) arranged on one edge of the board.