Semi-Flexible LED Substrate for Irregular Heat Sink Conformity
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Solution Overview
Problem
High power LED systems face challenges with thermal management due to the rigidity of standard circuit board materials, which leads to poor heat transfer and increased costs, as they are not effective in conforming to irregular heat sink surfaces and require labor-intensive assembly with thermal greases and mechanical fastening.
Innovation Solution
A layered structure comprising a top and bottom copper layer with a fiberglass intermediate layer, forming a semi-flexible elongate member, which includes a thermally conductive adhesive layer to fill voids and air gaps, allowing for better heat sink interface and reduced thermal resistance, enabling efficient heat transfer from high wattage LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid circuit board materials (FR4 or MCPCB) are used, then structural stability and electrical insulation are improved, but thermal conductivity and conformability to heat sink surfaces deteriorate
Solution Approach 1:
The circuit board is divided into multiple rigid layers (FR4 or MCPCB) separated by flexible insulating layers. This segmentation allows each layer to maintain its structural integrity while the flexible interlayers provide thermal conduction paths and conformability, resolving the contradiction between rigidity and thermal performance.
Solution Approach 2:
The invention uses a composite structure combining rigid circuit board materials (FR4 or MCPCB) with flexible thermally conductive insulating layers. This composite approach allows the rigid layers to provide structural stability while the flexible insulating layers enable thermal conduction and surface conformability, simultaneously addressing both requirements.
2Manufacturing precision
If rigid circuit board materials are used, then manufacturing precision and electrical insulation are improved, but thermal interface contact and heat transfer efficiency deteriorate
Solution Approach 1:
Flexible thermally conductive insulating layers are introduced as intermediary elements between the rigid circuit board layers and the heat sink. These intermediaries maintain electrical insulation while providing thermal conduction paths and ensuring intimate contact with the heat sink surface, thereby improving heat transfer efficiency without compromising electrical insulation.
Solution Approach 2:
The invention employs flexible thin film insulating layers that can conform to the heat sink surface topology. These flexible films maintain electrical insulation properties while enabling intimate thermal contact, resolving the contradiction between maintaining manufacturing precision and improving thermal interface reliability.
3Ease of manufacture
If standard circuit board materials are used, then cost is reduced, but thermal management performance and system reliability deteriorate
Solution Approach 1:
The invention creates a cost-effective composite structure using standard circuit board materials (FR4 or MCPCB) combined with flexible thermally conductive insulating layers. This composite approach maintains the cost advantages of standard materials while adding thermal management capabilities through the flexible insulating layers, improving reliability without significantly increasing cost.
Solution Approach 2:
The invention changes the thermal and mechanical parameters of the circuit board structure by introducing flexible thermally conductive insulating layers. This parameter change enables the use of standard, cost-effective circuit board materials while achieving improved thermal management performance and system reliability through enhanced thermal conduction and surface conformability.
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 provides a cost-effective, high thermal performance substrate that can conform to irregular heat sink surfaces, improving heat transfer efficiency and reducing assembly costs by using a semi-flexible structure with a thermally conductive adhesive layer, achieving thermal resistance of less than 5°C/W.
Implementation Method 1
the top layer, the intermediate layer, the bottom layer, and the adhesive layer have a thermal resistance of less than 1 to 5 degrees Celsius per Watt
Data Source
AI summary
A layered structure for use with a high power light emitting diode system comprises an electrically insulating intermediate layer interconnecting a top layer and a bottom layer. The top layer, the intermediate layer, and the bottom layer form an at least semi-flexible elongate member having a longitudinal axis and a plurality of positions spaced along the longitudinal axis. The at least semi-flexible elongate member is bendable laterally proximate the plurality of positions spaced along the longitudinal axis to a radius of at least 6 inches, twistable relative to its longitudinal axis up to 10 degrees per inch, and bendable to conform to localized heat sink surface flatness variations having a radius of at least 1 inch. The top layer is pre-populated with electrical components for high wattage, the electrical components including at least one high wattage light emitting diode at least 1.0 Watt per 0.8 inch squared.