Metal Base Circuit Board Thermal Expansion Management
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Solution Overview
Problem
Printed circuit boards for LED backlights face challenges in heat dissipation, leading to reduced brightness and shorter lifespan due to temperature rise, and existing methods either require accessory members or complex structures.
Innovation Solution
A metal base circuit board with an insulating layer, metal foil, and a specific area distribution of circuit and non-circuit portions, along with a white film, optimized for linear expansion coefficients and material composition to enhance heat dissipation without accessory members or thermal vias.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat is released through thermal vias to a heat releasing pattern on the reverse side, then heat dissipation is improved, but the constitution of the board becomes complex
Solution Approach 1:
The invention extracts the heat dissipation function from complex multi-layer structures and thermal vias, and concentrates it in the metal foil layer itself. The metal foil serves as both the circuit conductor and the primary heat dissipation path, eliminating the need for separate thermal management structures.
Solution Approach 2:
The metal foil performs multiple functions simultaneously: it serves as the circuit conductor, the structural base layer, and the primary heat dissipation path. This multi-functionality eliminates the need for separate thermal via structures and simplifies the overall board constitution.
2Temperature
If accessory members are used for heat dissipation, then heat dissipation performance is improved, but cost increases
Solution Approach 1:
The invention merges the heat dissipation function with the existing metal foil circuit board structure. By utilizing the metal foil's inherent thermal conductivity and making it the primary heat dissipation path, separate accessory heat dissipation members become unnecessary, thereby reducing manufacturing cost.
Solution Approach 2:
The metal foil circuit board serves its own heat dissipation needs through its inherent thermal properties. The structure is self-sufficient for thermal management without requiring additional accessory members, reducing both material cost and assembly complexity.
3Temperature
If the total area of circuit and non-circuit portions is increased relative to metal foil area, then heat dissipation is improved, but warpage control becomes difficult
Solution Approach 1:
The invention optimizes the linear expansion coefficient parameters of each layer to achieve thermal balance. By carefully selecting materials with appropriate expansion coefficients and optimizing their thickness ratios, the structure achieves both effective heat dissipation and warpage control through parameter optimization rather than area ratio adjustments.
Solution Approach 2:
The invention utilizes controlled thermal expansion differences between layers to manage warpage. The metal foil's linear expansion coefficient is specifically selected to be lower than the insulating layer but higher than the circuit pattern, creating a balanced expansion profile that prevents excessive warpage during thermal cycling while maintaining effective heat dissipation.
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 extends the operating lifespan of LEDs by improving heat dissipation and workability during circuit formation and mounting, while suppressing warpage and maintaining electrical reliability.
Implementation Method 1
a metal base circuit board having an insulating layer with a linear expansion coefficient of 60 ppm per degree C. or higher and 120 ppm per degree C. or lower, a metal foil provided on one side of the insulating layer, comprising a metal material with a linear expansion coefficient of 10 ppm per degree C. or higher and 35 ppm per degree C. or lower
Implementation Method 2
a white film formed on top of the insulating layer, circuit portion, and non-circuit portion
Implementation Method 3
the relation between the linear expansion coefficients of each of the materials being: linear expansion coefficient of insulating layer>linear expansion coefficient of metal foil>linear expansion coefficient of circuit portion and non-circuit portion
Data Source
AI summary
A metal base circuit board, having an insulating layer with a linear expansion coefficient of 60 ppm per degree C. or higher and 120 ppm per degree C. or lower, a metal foil provided on one side of the insulating layer, comprising a metal material with a linear expansion coefficient of 10 ppm per degree C. or higher and 35 ppm per degree C. or lower, a circuit portion and a non-circuit potion having a linear expansion coefficient of 10 ppm per degree C. or higher and 35 ppm per degree C. or lower, and a white film formed on top of the insulating layer, circuit portion, and non-circuit portion, the total sum of the areas of the non-circuit portion and the circuit portion on top of the insulating layer being 50% or higher and 95% or lower relative to the area of the metal foil and the relation between the linear expansion coefficients of each of the materials being: linear expansion coefficient of insulating layer>linear expansion coefficient of metal foil>linear expansion coefficient of circuit portion and non-circuit portion, such that Lifespan of LEDs can be lengthened, and the workability of the printed circuit board during circuit formation and during LED mounting can be improved.