LED Module Thermal Management via Insulating Plastic Body
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Solution Overview
Problem
Existing LED modules for motor vehicle headlights face challenges in heat dissipation and production complexity, particularly due to mechanical stresses from differing thermal expansion coefficients of ceramic and metal components.
Innovation Solution
An LED module with an electrically insulating plastic main body, a metal heat sink extending from the mounting surface to the base surface, and LED chips on ceramic substrates without growth substrates, allowing for efficient heat dissipation and reduced mechanical stresses through a thermally conductive connection to a metal-core circuit board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ceramic substrates are used for LED chips, then heat dissipation is improved, but mechanical stresses increase due to differing thermal expansion coefficients with metal components
Solution Approach 1:
The patent introduces a plastic main body as an intermediary material between the metal heat sink and the ceramic LED substrates. This plastic material has a thermal expansion coefficient that lies between that of metal and ceramic, acting as a buffer that reduces mechanical stresses while still allowing effective heat dissipation from the LED chips through the ceramic substrates to the heat sink.
Solution Approach 2:
The patent employs a composite structure consisting of multiple materials (plastic main body, metal heat sink, ceramic substrates) with complementary properties. The plastic provides mechanical stress relief, the metal provides thermal conduction, and the ceramic provides both thermal conduction and electrical insulation, creating a synergistic system that resolves the contradiction between heat dissipation and mechanical stress.
2Device complexity
If electrical connection contacts are made through the main body, then electrical connection is simplified, but electrical insulation is compromised
Solution Approach 1:
The patent segments the electrical connection function from the structural main body by providing dedicated connection contacts that are electrically insulated from the plastic main body. This segmentation allows the main body to maintain its electrical insulation properties while still enabling electrical connections through the insulated contacts, resolving the contradiction between connection simplicity and insulation reliability.
3Temperature
If LED modules are mounted on metal carriers, then heat dissipation is improved, but mechanical stresses increase due to thermal expansion differences
Solution Approach 1:
The plastic main body serves as an intermediary mounting structure between the LED ceramic substrates and the external metal carrier. This plastic interface layer has thermal expansion properties that bridge the gap between ceramic and metal, reducing mechanical stresses during thermal cycling while still allowing the metal carrier to provide effective heat dissipation pathways.
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 effective heat dissipation with low production complexity, reducing thermal resistance and mechanical stresses, enabling reliable operation and easy mounting on various surfaces without high mechanical stresses.
Implementation Method 1
The heat sink advantageously extends from the mounting surface as far as the base surface of the LED module. In this way, the heat sink advantageously forms a thermally conductive connection between the mounting surface and the base surface.
Implementation Method 2
Each of the plurality of LED chips can emit the heat generated during operation via its carrier substrate to the common heat sink.
Data Source
AI summary
An LED module has an electrically insulating main body, a base surface and a mounting surface located opposite the base surface. A number of electrical connection contacts are arranged at the mounting surface. The connection contacts do not adjoin the base surface. A heat sink is arranged in the main body. The heat sink extends from the mounting surface as far as the base surface. Furthermore, the LED module has a number of LED chips, each having an electrically insulating carrier substrate at a chip underside and two chip contacts at a chip top side. The LED chips are arranged with the electrically insulating carrier substrate on the heat sink.