LED Phosphor Layer Support Structure for Uniform Color Emission
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Solution Overview
Problem
Conformal luminophoric medium layers on LEDs tend to thin at corners, leading to non-uniform color emission due to reduced interaction with luminescent materials, resulting in 'halo' effects in undesired color ranges.
Innovation Solution
A support layer, typically made of transparent optical materials like silicone or epoxy, is used to shape and extend over the corners of LEDs, preventing thinning of the luminophoric medium layer and ensuring uniform light emission by creating smooth transitions between the LED's surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conformal luminophoric medium layer is applied directly on the LED surface, then the manufacturing process is simple, but the layer thins at corners causing non-uniform color emission
Solution Approach 1:
A support layer made of transparent optical material (such as silicone or epoxy) is introduced as an intermediary between the LED and the luminophoric medium layer. This support layer provides a smooth, rounded surface that prevents the luminophoric medium layer from thinning at corners, thereby maintaining uniform thickness and consistent color emission while still allowing for a relatively simple manufacturing process
2Quantity of substance
If the luminophoric medium layer is thin at corners, then less material is required, but color uniformity deteriorates due to reduced interaction with luminescent materials
Solution Approach 1:
The support layer acts as a mediator that ensures sufficient thickness of the luminophoric medium layer at corner regions by providing a rounded geometric foundation. This maintains consistent color composition across the entire LED surface including corners, while the support layer itself is made of transparent material that does not interfere with light transmission
3Device complexity
If the luminophoric medium layer thickness varies at corners, then the device structure remains simple, but 'halo' effects appear in undesired color ranges
Solution Approach 1:
The transparent support layer serves as a simple structural intermediary that eliminates the geometric sharpness of LED corners, preventing the luminophoric medium layer from thinning and thereby eliminating halo effects. The solution adds minimal complexity while effectively resolving the harmful color emission artifacts
4Stability of the object's composition
If a support layer is added to shape the luminophoric medium layer, then color uniformity is improved, but the device complexity increases
Solution Approach 1:
The support layer is designed to serve multiple functions simultaneously: it provides mechanical support for the luminophoric medium layer, creates the desired rounded geometry to prevent thinning at corners, and is made of transparent optical material that allows light transmission. This multi-functionality minimizes the added complexity while achieving color uniformity improvement
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 support layer ensures that the luminophoric medium layer maintains even thickness, enhancing color uniformity and preventing 'halo' effects, thereby improving the overall color consistency of the emitted light.
Implementation Method 1
luminescent materials may absorb light having first wavelengths and re-emit light having second wavelengths that are different from the first wavelengths
Implementation Method 2
down-conversion luminescent materials may absorb light having shorter wavelengths and re-emit light having longer wavelengths
Data Source
AI summary
A light emitting device includes a LED having a light emitting first surface and a light emitting second surface that define a corner. A support layer is disposed to receive light emitted by the light emitting second surface and is disposed adjacent the corner. A luminophoric medium layer at least partially covers the light emitting first surface and the light emitting second surface where the luminophoric medium layer is at least partially supported by the support layer to prevent a narrowing of the luminophoric medium layer.