Gradient Porosity Ceramic Coating for LED Thermal Management
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Solution Overview
Problem
High-intensity LEDs on carrier elements face overheating issues due to high power loss, leading to degradation and premature failure, requiring effective cooling while maintaining electrical insulation, which is challenging with existing ceramic and metal heat sinks.
Innovation Solution
A carrier element with a metallic core coated by a plasma-chemically produced oxide ceramic layer, featuring increasing porosity from the core interface to the surface, providing high electrical discharge resistance and good adhesion for components, combined with high thermal conductivity for efficient heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ceramic heat sink is used for electrical insulation, then electrical insulation is achieved, but thermal conductivity is insufficient leading to poor cooling
Solution Approach 1:
The invention uses a composite structure combining aluminum base material with anodized oxide layer. The aluminum provides high thermal conductivity for effective cooling, while the anodized oxide layer provides electrical insulation. This composite approach resolves the contradiction by integrating materials with complementary properties.
Solution Approach 2:
The invention changes the surface treatment parameters of the aluminum by applying controlled anodization to create an oxide layer with specific thickness (5-50 microns) and porosity characteristics. This parameter change enables the surface to provide electrical insulation while maintaining the underlying aluminum's thermal conductivity.
2Reliability
If an oxide layer is applied by anodic oxidation for electrical insulation, then electrical insulation is achieved, but the layer becomes porous leading to electrical flashovers
Solution Approach 1:
The invention applies local quality by creating different pore densities at different locations within the oxide layer. The layer has lower porosity near the aluminum substrate interface and higher porosity toward the surface. This gradient structure provides electrical insulation at the critical interface while allowing controlled porosity elsewhere for adhesion.
Solution Approach 2:
The invention utilizes controlled porosity in the anodized oxide layer, accepting that some porosity exists but managing it through the gradient structure. The lower porosity region at the interface prevents electrical flashovers, while the higher porosity region maintains adhesion properties for component mounting.
3Reliability
If pores are closed by impregnation to prevent electrical flashovers, then electrical insulation is improved, but adhesion of circuits is reduced
Solution Approach 1:
The invention avoids the need for impregnation by creating local quality differences within the oxide layer itself. The gradient porosity structure provides electrical insulation at the interface without requiring pore closure, thereby maintaining adhesion properties through the naturally formed porous structure in the upper regions.
4Temperature
If additional cooling measures are added to the carrier element, then cooling effectiveness is improved, but device complexity and costs increase
Solution Approach 1:
The invention makes the carrier element multi-functional by integrating cooling and electrical insulation functions into a single component. The anodized aluminum carrier element simultaneously provides structural support, thermal management, and electrical insulation, eliminating the need for separate cooling components.
Solution Approach 2:
The invention merges the cooling function and electrical insulation function into one integrated carrier element. The aluminum base material provides cooling, while the anodized oxide layer provides insulation, combining what would traditionally be separate components into a single unified structure.
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 enables efficient heat dissipation and reliable electrical insulation, reducing the risk of overheating and assembly complexity, while allowing the carrier element to function as both a heat sink and electrical insulation layer, thus extending LED component life and simplifying manufacturing.
Implementation Method 1
The oxide ceramic layer (22) is produced on the metallic core (2) by oxidizing the partial area (21) of its surface by means of a plasma-chemical method with spark discharges
Implementation Method 2
Applying a sufficiently high voltage causes a spark discharge at the surface of the metal. This creates an oxygen plasma that forms the oxide ceramic layer
Implementation Method 3
The high performance of the LEDs often results in a high power loss. This can cause the LEDs to overheat, which can lead to degradation of the component properties
Data Source
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AI summary
The invention relates to an LED carrier element (1) comprising: a metallic core having an oxide ceramic layer (22) on at least a partial area of its surface (21), wherein the oxide ceramic layer (22) has a porosity that increases from the interface to the metallic core (2) to the surface (21) of the carrier element, at least one conductor track (3) arranged on a partial area on the side of the oxide ceramic layer (22) facing away from the metallic core (2), and at least one LED (5) in electrical contact with the conductor track (3).