LED Illumination Module With Composite Copper-Aluminum Cooling
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Solution Overview
Problem
High-power LED illumination systems face limitations in achieving high power densities due to the poor thermal conductivity of semiconductor materials, leading to restricted brilliance and power density, especially in non-planar arrays, which are necessary for applications like street illumination and technical lighting.
Innovation Solution
An LED illumination module with multiple LED elements mounted on a substrate, utilizing a secondary cooling element with a high thermal conductivity material and heat pipes to efficiently manage heat, while separating heat dissipation from power supply to optimize both functions, and incorporating a current supply member with slits to mitigate mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If LED chips are assembled on aluminum core circuit boards with conventional SMD techniques, then the structure is simple and easy to manufacture, but the thermal conductivity is insufficient and power density is limited
Solution Approach 1:
The patent employs a composite substrate structure consisting of an aluminum core circuit board combined with a copper layer. This composite material approach leverages the electrical conductivity of aluminum and the superior thermal conductivity of copper, achieving both ease of manufacture and high power density by integrating materials with complementary properties.
Solution Approach 2:
The invention merges the functions of the substrate and cooling element by integrating a copper layer directly onto the aluminum core circuit board. This combination creates a unified structure that simultaneously provides electrical connectivity, mechanical support, and enhanced heat dissipation, resolving the contradiction between manufacturing simplicity and thermal performance.
2Temperature
If distances of 20 to 30 mm are maintained between LED chips on aluminum substrates, then thermal management is feasible, but the brilliance and power density are limited
Solution Approach 1:
By incorporating a copper layer into the substrate structure, the patent enhances thermal conductivity without requiring increased spacing between LED chips. The copper layer creates efficient thermal pathways that conduct heat away from closely spaced chips, enabling high brilliance while maintaining effective thermal management.
Solution Approach 2:
The patent introduces a vertical dimension to heat dissipation by implementing a multi-layer substrate structure with the copper layer positioned beneath the aluminum core. This vertical thermal conduction path complements the traditional planar heat spreading, allowing for higher chip density while maintaining thermal management through three-dimensional heat flow management.
3Power
If copper substrates are used to increase thermal conductivity, then power density increases, but the system quickly reaches its limit with more than four clustered 4 W-LEDs
Solution Approach 1:
The patent uses a composite aluminum-copper substrate structure that combines the advantages of both materials. The aluminum core provides cost-effectiveness and electrical conductivity, while the copper layer enhances thermal conductivity. This composite approach achieves high power density without the limitations of pure copper substrates, allowing for scaling beyond four clustered LEDs.
Solution Approach 2:
The substrate is segmented into functional layers with the aluminum core circuit board handling electrical connectivity and structural support, while the copper layer is dedicated to thermal management. This segmentation allows each layer to be optimized for its specific function, enabling the system to handle higher power densities without increasing overall system complexity.
4Illumination intensity
If non-planar LED arrays are arranged to achieve high power density, then brilliance increases, but it is difficult to realize acceptable light guiding quality
Solution Approach 1:
The patent applies local quality optimization by enhancing thermal conductivity specifically in regions where LED chips are mounted, using the copper layer positioned beneath the aluminum core. This localized thermal enhancement allows for non-planar array configurations that achieve high brilliance while maintaining manufacturing precision, as the improved heat dissipation compensates for the complexity of non-planar geometries.
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
This configuration allows for significantly higher power densities, enabling the creation of compact, long-lasting high-power LED light sources with reduced temperature gradients and mechanical stress, suitable for diverse applications including street and technical lighting.
Implementation Method 1
at least one secondary cooling element is provided... which allows for a fourfold power density as compared to aluminum substrates (λCu999=401 Wm−1K−1)
Implementation Method 2
utilizing a secondary cooling element with a high thermal conductivity material and heat pipes to efficiently manage heat
Data Source
AI summary
An LED illumination module is described, where a row of LED elements (1) is arranged via a substrate (16) on a secondary cooling element (2). The secondary cooling element (2) can consist of a first material layer (16, 17) of copper and a second material layer (18) of aluminium. In such material combinations, phononic refraction leads to a good lateral heat distribution, which improves the heat flow and reduces temperature gradients. Alternatively or in addition thereto, the secondary cooling element (2) can be equipped with heat pipes. The LED elements (1) are electrically contacted by means of a current supply member (21) arranged at a distance from the substrate (16).