Multilayer Phosphor Film for LED Thermal Management
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Solution Overview
Problem
Conventional phosphor-coated LEDs with silicone carriers face thermal conductivity issues, leading to cracking and reduced lifetime in high-power applications, and existing methods struggle to achieve a thin, high-concentration phosphor layer with effective thermal dissipation and uniform coverage.
Innovation Solution
A process involving a mixture of uncurable silicone, treated silica, and phosphor is dispensed onto a surface, sonicated, and partially dried, followed by application of a curable silicone layer, which is then cured to form a multilayer film with a high phosphor concentration (60-80%) and a rigid, phosphor-free silicone layer for enhanced thermal conductivity and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a cured silicone carrier is used to encapsulate phosphor particles, then the phosphor particles remain suspended and the structure is stable, but the poor thermal conductivity causes cracking and reduced lifetime in high-power applications
Solution Approach 1:
The invention divides the encapsulation structure into two distinct layers: a lower cured silicone carrier layer that provides structural stability and phosphor suspension, and an upper uncurable silicone layer that provides thermal conduction pathways. This segmentation allows each layer to fulfill its specific function without compromising the other, resolving the contradiction between stability and reliability.
Solution Approach 2:
The invention creates a composite material structure combining cured and uncurable silicone layers with phosphor particles. The uncurable silicone layer acts as a thermal conduit that bypasses the poor thermal conductivity of the cured silicone, while the cured silicone maintains structural integrity. This composite approach simultaneously achieves both stability and improved thermal management for enhanced reliability.
2Illumination intensity
If a thick phosphor layer is formed to achieve sufficient light conversion, then broad-spectrum white light is produced, but thermal dissipation becomes inadequate and efficiency is reduced
Solution Approach 1:
The invention applies different material properties to different regions of the encapsulation structure. The lower layer uses cured silicone optimized for structural stability and phosphor suspension, while the upper layer uses uncurable silicone optimized for thermal conduction. This local differentiation allows the phosphor layer to maintain sufficient thickness for light conversion while the upper layer efficiently conducts away generated heat, reducing energy loss.
3Ease of manufacture
If conventional single-layer phosphor coating is applied, then the process is simple, but achieving thin, high-concentration phosphor layer with uniform coverage and effective thermal dissipation is difficult
Solution Approach 1:
The manufacturing process is segmented into two distinct coating steps: first applying the cured silicone carrier with phosphor particles to achieve uniform distribution and high concentration, then applying the uncurable silicone layer for thermal management. This segmentation of the manufacturing process enables precise control over phosphor layer characteristics while maintaining relative process simplicity.
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 a thin, high-concentration phosphor layer with improved thermal dissipation and mechanical strength, addressing the thermal conductivity limitations of silicone carriers and enhancing the efficiency and reliability of LEDs in high-power applications.
Implementation Method 1
The phosphor material is generally formed by introducing a suspension of phosphor particles into a carrier (e.g., silicone)
Implementation Method 2
The cured silicone may crack and/or have a reduced lifetime... silicone is a poor thermal conductor... cracks in the phosphor and silicone composition reduce the efficiency
Implementation Method 3
The phosphor material converts monochromatic light emitted from the blue or UV LEDs to white light
Data Source
AI summary
A multiple layer film and a method of manufacturing the same, the film having a phosphor bearing layer including phosphor and a carrier, and a rigid protective layer. In some embodiments a mixture including phosphor and an uncurable fluid are dispensed onto a surface, and the mixture is at least partially dried. A curable fluid is dispensed onto the at least partially dried mixture, and the curable fluid is cured.