PCB Conductive Layer for Heat-Sink Contact and Electrical Isolation

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Solution Overview

Problem

Existing printed circuit boards face challenges in efficiently transferring heat outside the board due to the contradictory requirements of thinness for low thermal resistance and thickness for electrical insulation at the PCB-heatsink interface, leading to compromised thermal and electrical performance, and current solutions like gap fillers and thermal tapes are costly and complex.

Innovation Solution

A printed circuit board design with an insulating bulk layer providing internal insulation, allowing a distal conductive layer to be directly connected to a heat sink, eliminating the need for additional insulation and enabling efficient heat transfer through a planar, smooth conductive structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the PCB is made thinner at the interface to reduce thermal resistance, then heat transfer efficiency improves, but electrical insulation between conductive layers deteriorates

Engineering Contradiction:
Improvethermal resistanceVSAvoidelectrical insulation
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The PCB is segmented into multiple layers with distinct functional zones: an first conductive layer for electrical connections, an insulating layer for electrical isolation, and a second conductive layer for heat dissipation. This segmentation allows each layer to optimize its specific function without compromising the others, resolving the contradiction between thermal conductivity and electrical insulation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the PCB have different properties: the first conductive layer is optimized for electrical connectivity with appropriate trace patterns, while the second conductive layer is optimized for thermal conductivity with continuous copper planes. The insulating layer thickness is locally adjusted to maintain electrical isolation while allowing efficient heat transfer where needed.

Inventive Principle:
Principle #3Local quality

2Reliability

If additional insulation layers are added to ensure electrical isolation, then electrical safety improves, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveelectrical insulationVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The insulating layer serves multiple functions simultaneously: it provides electrical isolation between the first and second conductive layers, acts as a structural support layer, and facilitates heat transfer from the first to the second conductive layer. This multi-functionality eliminates the need for separate insulation components, reducing manufacturing complexity while maintaining electrical safety.

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

Solution Approach 2:

The patent merges the insulation function with the structural PCB layers themselves rather than using separate insulation components. The insulating layer is integrated into the PCB stack-up as a standard prepreg or core material, combining electrical isolation with mechanical support and thermal management in a single unified structure.

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

The solution enhances heat dissipation properties by maintaining electrical insulation while allowing direct connection to a heat sink, improving thermal conductivity and reducing production costs and complexity.

Implementation Method 1

allowing a distal conductive layer to be directly connected to a heat sink, enabling efficient heat transfer through a planar, smooth conductive structure

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

an insulating bulk layer providing internal insulation, allowing a distal conductive layer to be directly connected to a heat sink, eliminating the need for additional insulation

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentEP4622399A1Printed circuit board, electrical circuit assembly and methods of producing a printed circuit board and an electrical circuit assembly
Publication Date: 2025.09.24 ZF CV SYST GLOBAL GMBH
  • EP4622399A1 patent drawingFigure 1
  • EP4622399A1 patent drawingFigure 2
  • EP4622399A1 patent drawingFigure 3

AI summary

The invention is directed to a printed circuit board (100) comprising an insulating bulk layer (102) having a proximal surface (102a) and a distal surface (102b) that is opposite to the proximal surface (102a) one or more electrical connection elements (104) accessible from the proximal surface (102a) of the insulating bulk layer (102), the electrical connection elements (104) configured to connect electrical components (202) to be arranged on the proximal surface (102a) of the insulating bulk layer (102), wherein the distal surface (102b) is at least partially covered by a distal conductive layer (106) that is electrically isolated from the electrical connection elements (104).