Heat-Diffusion Sheet Composition for Burr-Resistant Insulation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Heat-diffusion sheets used in electronic components face insulation failure due to burrs or foreign matter, leading to excessive electric current flow and potential damage, which existing technologies struggle to prevent effectively.

Innovation Solution

A heat-diffusion sheet with a thickness of more than 10 μm, containing a resin binder and inorganic filler, specifically coagulated hexagonal boron nitride particles, and a method of production involving pre-heating and curing under pressure to minimize voids and enhance insulation, ensuring dielectric breakdown occurs at a controlled distance between a needle electrode and an aluminum plate, thereby preventing short circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If heat-diffusion sheets are used to conduct heat efficiently, then thermal conductivity is improved, but insulation failure occurs due to burrs or foreign matter causing excessive electric current flow

Engineering Contradiction:
Improveinsulation reliabilityVSAvoidinsulation failure
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies beforehand cushioning by introducing a resin layer between the heat-diffusion sheet and the heat-generating component surface. This resin layer acts as a buffer that absorbs or isolates the harmful effect of burrs and foreign matter before they can cause insulation failure. The resin layer is applied in advance during the manufacturing process, creating a protective barrier that prevents direct contact between conductive elements and potential contaminants on the component surface.

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

Solution Approach 2:

The patent employs an intermediary approach by using a resin layer as a mediator between the heat-diffusion sheet and the heat-generating component. This intermediary layer serves multiple functions: it maintains thermal contact while electrically isolating the system from burrs and foreign matter. The resin layer transfers the necessary mechanical pressure for thermal conduction while blocking the harmful electrical conduction path that would otherwise occur through conductive contaminants.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If heat-diffusion sheets with thin thickness are used, then ease of handling and installation is improved, but insulation performance deteriorates making them more susceptible to breakdown

Engineering Contradiction:
Improveease of handlingVSAvoidinsulation performance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies composite materials by combining the heat-diffusion sheet with a resin layer to create a composite thermal interface structure. This composite system maintains the thin profile and ease of handling of the original heat-diffusion sheet while adding the insulation properties of the resin layer. The combination allows the thin sheet to retain its mechanical flexibility and ease of installation while the resin component provides the necessary electrical insulation and burr resistance.

Inventive Principle:
Principle #40Composite materials

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 suppresses insulation failure caused by burrs or foreign matter, ensuring reliable electric insulation and thermal conductivity in heat-diffusion sheets, even when defects are present, by maintaining a controlled distance at dielectric breakdown and enhancing the sheet's mechanical strength and thermal resistance.

Implementation Method 1

heat-diffusion sheet having a thickness of more than 10 μm... capable of suppressing the generation of insulation failure... in heat-diffusion sheets

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a distance between a distal end of a needle electrode and an aluminum plate at the time of dielectric breakdown of the heat-diffusion sheet

Methodology Applied
Scientific EffectDielectric breakdown: Dielectric

Data Source

PatentEP4002443B1Heat-radiating sheet and method of producing heat-radiating sheet
Publication Date: 2024.06.26 DENKA CO LTD
  • EP4002443B1 patent drawingFigure 1
  • EP4002443B1 patent drawingFigure 2
  • EP4002443B1 patent drawingFigure 3~4

AI summary

The present invention relates to a heat-diffusion sheet (30) in which when a needle electrode (23) having a cone having a height of 3 mm and a bottom surface diameter of 0.75 mm at a distal end section (231) thereof, to which a 2.0-kV alternating current voltage having a frequency of 60 Hz has been impressed, is not only penetrated stepwise every 10 µm but also retained for 60 seconds before the penetration and at each of the steps, a distance between the distal end of the needle electrode (23) and an aluminum plate (25) at the time of dielectric breakdown of the heat-diffusion sheet (30) is larger than 0 pm and 80 pm or less, or the needle electrode short-circuits the aluminum plate (30) without dielectric breakdown of the heat-diffusion sheet (30). The production method of a heat-diffusion sheet of the present invention includes a pre-heating step of pre-heating a composition sheet for heat-diffusion sheet at a pre-heating temperature lower than a curing starting temperature while pressurizing the composition sheet for heat-diffusion sheet; and a curing step of heating the composition sheet for heat-diffusion sheet at a temperature of the curing starting temperature or higher while pressurizing the pre-heated composition sheet for heat-diffusion sheet. In accordance with the present invention, it is possible to provide a heat-diffusion sheet capable of suppressing generation of insulation failure owing to a burr in the heat-diffusion component or a foreign matter incorporated between a heat-generating electronic component and a heat-diffusion sheet or between a heat-diffusion component and the heat-diffusion sheet; and a method of producing the heat-diffusion sheet.