Heat Dissipating Sheet With Recessed Resin and Conductive Film

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Solution Overview

Problem

Conventional thermally-conductive sheets used for heat dissipation in electronic devices have unsatisfactory thermal conductivity, leading to poor heat dissipation and transfer, and the use of liquid resin with fillers can result in contamination and adhesion issues with printed circuit boards.

Innovation Solution

A heat-dissipating sheet comprising a thermally-conductive resin sheet with a locally thin portion forming a recess, an adhesive layer, and a thermally-conductive film with higher conductivity, allowing secure attachment and efficient heat transfer without the need for hardening, and facilitating easy removal from printed circuit boards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a thermally-conductive sheet is made by hardening a mixture of resin and thermally-conductive filler, then the sheet can be applied to heat-generating components, but the thermal conductivity is unsatisfactory and heat dissipation is poor

Engineering Contradiction:

Improveheat dissipation performanceVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses a composite structure combining a thermally-conductive resin sheet with a thermally-conductive film having higher thermal conductivity. This composite material approach allows achieving satisfactory heat dissipation performance by layering materials with complementary properties, where the film provides high thermal conductivity pathways while the resin sheet provides structural support and filling capabilities.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent introduces a thin portion (recess) at a specific location of the thermally-conductive resin sheet, creating local variation in thickness. This local quality change allows the sheet to conform to the heat-generating component surface more effectively, ensuring intimate thermal contact where needed most, while maintaining overall structural integrity.

Inventive Principle:

Principle #3Local quality

2Reliability

If liquid resin with thermally-conductive filler is used to contact heat-generating components, then heat transfer can be achieved, but contamination and adhesion issues with printed circuit boards occur

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidcontamination and adhesion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical state parameter of the thermally-conductive material from liquid resin to a solid sheet structure. By transforming the material form and eliminating the liquid phase, the patent prevents contamination and adhesion problems that occur with liquid resin, while maintaining effective heat transfer through the solid thermally-conductive film and resin sheet combination.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a uniform thickness thermally-conductive sheet is used, then manufacturing is simpler, but heat dissipation efficiency is reduced due to poor contact with component surfaces

Engineering Contradiction:

Improvethermal contact efficiencyVSAvoidsheet structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The thermally-conductive resin sheet is segmented into regions of different thickness, with a thin portion creating a recess. This segmentation allows the sheet to adapt to varying surface geometries of heat-generating components, improving thermal contact efficiency without requiring a completely complex structure.

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

The solution effectively reduces heat resistance and enhances heat dissipation by using a thermally-conductive film with significantly higher conductivity than the resin sheet, allowing for efficient heat transfer and secure attachment with reduced pressure on components, while preventing contamination and simplifying reattachment.

Implementation Method 1

a thermally-conductive film (34) provided on an upper surface of the adhesive layer (33). The thermally-conductive film (34) has a larger thermal conductivity than the thermally-conductive resin sheet (31)

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

an adhesive layer (33) provided on an upper surface of the thermally-conductive resin sheet (31)

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS10091868B2Heat dissipating sheet and heat dissipating structure using same

Publication Date: 2018.10.02 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A heat-dissipating sheet includes a thermally-conductive resin sheet, an adhesive layer on an upper surface of the thermally-conductive resin sheet, and a thermally-conductive film on an upper surface of the adhesive layer. The thermally-conductive film has a higher thermal conductivity than the thermally-conductive resin sheet. The thermally-conductive resin sheet has a thin portion that is locally thin to form a recess in a lower surface of the thermally-conductive resin sheet. The recess may be an aperture passing through the thermally-conductive resin sheet. The adhesive layer is exposed from the aperture.