PCB Solder Joint Layout for Concealed Connection Testing

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Solution Overview

Problem

Existing methods for inspecting solder joints on printed circuit boards are inadequate for detecting concealed defects such as cold solder joints and ensuring intrinsic safety in electronic units, particularly in field devices used in process and automation engineering.

Innovation Solution

The electronic unit design involves applying solder paste to multiple spaced contact surfaces and terminals, forming separate solder joints that require the presence of a component for a complete electrical connection, allowing for indirect testing through input and output signal measurement to verify the integrity of the solder joints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If automatic optical inspection (AOI) is used to inspect solder joints, then inspection speed and automation are improved, but concealed solder joints cannot be detected

Engineering Contradiction:

Improveautomation of inspectionVSAvoiddetection of concealed solder joints

Core Design Contradiction:

Extent of automationVSDifficulty of detecting and measuring

Solution Approach 1:

The patent introduces an intermediary test component with known electrical characteristics that is soldered to the same contact surfaces as the actual component. This intermediary serves as a reference for indirect testing, allowing detection of concealed solder joint defects through electrical property comparisons without requiring direct visual access to the solder joints.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Difficulty of detecting and measuring

If automatic X-ray inspection (AXI) is used to detect concealed defects, then detection capability is improved, but device complexity and cost increase

Engineering Contradiction:

Improvedetection of concealed defectsVSAvoidcomplexity of inspection method

Core Design Contradiction:

Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The patent employs a simple, inexpensive electrical testing method using basic measurement equipment instead of expensive X-ray inspection systems. The test component and testing procedure are designed to be simple and straightforward, providing an affordable alternative that achieves the detection goal without complex equipment.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent replaces the mechanical/optical/X-ray inspection system with an electrical testing system. Instead of physically examining or imaging the solder joints, the method uses electrical property measurements (resistance, capacitance, inductance) to indirectly detect defects, substituting a simpler electrical measurement approach for complex physical inspection methods.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If solder paste is applied to multiple contact surfaces, then electrical connection verification is improved, but manufacturing process complexity increases

Engineering Contradiction:

Improveelectrical connection integrityVSAvoidsoldering process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies solder paste to multiple contact surfaces in advance during the soldering process, creating multiple potential solder joints simultaneously. This preliminary preparation ensures that when the component is mounted, electrical connections are established across multiple points, enabling comprehensive indirect testing without requiring complex post-soldering modifications to the manufacturing process.

Inventive Principle:

Principle #10Preliminary action

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

Enables simple and effective detection of concealed solder joints, ensuring mechanical and electrical connectivity, reducing tilting issues, and facilitating functional testing without additional effort, thereby enhancing manufacturing quality and safety.

Implementation Method 1

the at least one terminal is joined to the at least two contact surfaces by means of at least one solder joint

Methodology Applied

Scientific EffectSoldering: Soldering

Implementation Method 2

Before the at least one component is soldered to the printed circuit board, the solder paste is either applied to the first contact surface and the second contact surface

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 3

applying an electrical input signal to the at least one first contact surface, determining an electrical output signal on the at least one second contact surface

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS12498411B2Electronic unit and method for testing at least one state of an electronic unit

Publication Date: 2025.12.16 ENDRESS & HAUSER GMBH & CO KG

AI summary

An electronic unit includes at least one component and a printed circuit board, wherein the at least one component has at least one terminal. The printed circuit board has at least one first contact surface and at least one second contact surface, wherein the at least one first contact surface and the at least one second contact surface are spaced apart from one another. The at least one terminal is joined to the at least two contact surfaces by at least one solder joint. A method for testing at least one state of an electronic unit is also disclosed.