Printed Board Heat Sink Recess Segmentation

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Solution Overview

Problem

The existing methods for embedding heat dissipation members in printed boards often result in residual stress due to burrs at the boundary between the heat dissipation member and the base member, leading to potential disconnection of wiring patterns as the board expands or shrinks with temperature changes.

Innovation Solution

A printed board design featuring a recess portion with alternating contact and separation areas, where the heat dissipation member is fitted, and the wiring patterns are positioned to avoid overlapping with the contact areas, ensuring that residual stress is not generated on the separation portions, thus preventing wiring pattern disconnection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the heat dissipation member is fitted into the through-hole of the base member, then heat dissipation function is improved, but burrs are generated at the boundary portion causing residual stress and potential wiring pattern disconnection

Engineering Contradiction:

Improveheat dissipation efficiencyVSAvoidwiring pattern connection reliability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The harmful burrs generated at the boundary portion are removed by forming the recess portion smaller than the heat dissipation member, allowing the excess material to be extracted and preventing residual stress that would cause wiring pattern disconnection

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The recess portion is designed with specific dimensional characteristics (smaller than the heat dissipation member) to create a localized fit that eliminates burr formation at the critical boundary area, while maintaining overall heat dissipation functionality

Inventive Principle:

Principle #3Local quality

2Stability of the object's composition

If the inner circumferential surface of the recess portion and outer circumferential surface of the heat dissipation member are made to be in partial contact, then the heat dissipation member is prevented from getting out, but residual stress is generated around burrs leading to wiring pattern disconnection

Engineering Contradiction:

Improveheat dissipation member positioning stabilityVSAvoidwiring pattern connection reliability

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

By designing the recess portion to be smaller than the heat dissipation member, the harmful burrs are extracted or eliminated, preventing residual stress accumulation that would compromise wiring pattern reliability while maintaining positioning stability through the interference fit

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If the wiring pattern passes through the position vertically overlapping the contact portion, then electrical connection is maintained, but the wiring pattern is disconnected due to residual stress from burrs during thermal expansion and contraction

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidwiring pattern structural integrity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The harmful burrs are removed by the recess portion design, eliminating the source of residual stress that would cause wiring pattern disconnection during thermal cycling, thereby protecting wiring integrity without compromising electrical connection

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The boundary portion is segmented into contact portions and separation portions, allowing the wiring pattern to be positioned on separation portions where no burrs exist, thus avoiding residual stress concentration points while maintaining electrical connectivity

Inventive Principle:

Principle #1Segmentation

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 design effectively prevents wiring pattern disconnection at the boundary between the heat dissipation member and the base member, maintaining electrical reliability and ensuring efficient heat dissipation.

Implementation Method 1

a gap between the recess portion and the heat dissipation member is filled with the thermosetting resin of the base member melted by heating

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

heat generated in electronic components mounted on the printed board is dissipated by a heat dissipation member embedded in the printed board

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS9924590B2Printed board and electronic apparatus

Publication Date: 2018.03.20 OMRON CORP

AI summary

A printed board includes: a base member; a recess portion provided in the base member; a heat dissipation member fitted into the recess portion; and a wiring pattern provided on an upper side of the base member and the heat dissipation member via an insulator. A contact portion in which an inner circumferential surface of the recess portion and an outer circumferential surface of the heat dissipation member contact each other and a separation portion in which those do contact each other are formed. A gap between the recess portion and the heat dissipation member is filled with thermosetting resin of the base member melted by heating. At least a partial portion in a width direction of the wiring pattern passes through a position vertically overlapping the separation portion while an entire portion thereof does not pass through a position vertically overlapping the contact portion.