LED Package Curved Phosphor Layer for Uniform Light Distribution
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Solution Overview
Problem
Existing light emitting device packages face challenges in achieving uniform color distribution and efficient light emission due to limitations in heat dissipation and moisture protection, particularly in the packaging of LED chips on ceramic substrates.
Innovation Solution
A light emitting device package is designed with a ceramic substrate, an LED chip, a first light-transmissive resin layer covering the chip, a phosphor layer on top of the resin layer, and a second light-transmissive resin layer with a lens unit, where the phosphor layer is thinner than the resin layer and the resin layers are optimized in width and thickness to enhance light diffusion and heat dissipation, along with a moisture barrier layer to prevent moisture ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the phosphor layer is made thick to improve light diffusion, then light emission uniformity is improved, but the package height increases and manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by creating a curved surface structure at specific locations where the phosphor layer contacts the resin layers, rather than uniformly increasing the entire phosphor layer thickness. This localized curvature modification achieves improved light diffusion and uniformity without proportionally increasing overall package height.
Solution Approach 2:
The patent utilizes curvature by forming a curved surface at the contact regions between the phosphor layer and resin layers. This curved geometry enhances light scattering and diffusion properties, improving emission uniformity while maintaining a compact overall structure compared to a uniformly thick phosphor layer.
2Illumination intensity
If the resin layers are optimized for light diffusion, then light emission uniformity is improved, but heat dissipation efficiency may be compromised
Solution Approach 1:
The patent divides the resin structure into multiple segments: a first resin layer, a phosphor layer, and a second resin layer with a lens unit. This segmentation allows each layer to be optimized for its specific function - the first resin layer for light diffusion, the phosphor layer for wavelength conversion, and the second resin layer with lens for light extraction and directional control, while heat dissipation paths are maintained through the ceramic substrate.
Solution Approach 2:
The resin layers serve multiple functions simultaneously: they provide optical diffusion for uniform light emission, structural encapsulation for moisture protection, and thermal management pathways. The curved surface structure in particular serves both optical diffusion and maintains compact packaging dimensions.
3Manufacturing precision
If the first resin layer width is reduced to match the ceramic substrate, then manufacturing precision is improved, but light extraction efficiency may decrease
Solution Approach 1:
The curved surface structure at the phosphor-resin interface acts as an optical element that enhances light extraction efficiency through increased optical path length and scattering effects. This curvature compensation allows the first resin layer to have a width matching the ceramic substrate while maintaining high light extraction through the enhanced optical interaction at the curved interface.
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 achieves uniform color distribution and improved light emission with enhanced heat dissipation and moisture protection, leading to a more reliable and efficient light emitting device package.
Implementation Method 1
a phosphor layer on the first light-transmissive resin layer
Implementation Method 2
a first light-transmissive resin layer on the ceramic substrate to cover the light emitting device, and a second light-transmissive resin layer on the phosphor layer
Data Source
Figure 1~2
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Figure 5~6
AI summary
Disclosed are a light emitting diode package and a light unit having the same. The light emitting diode package includes a ceramic substrate (110); a light emitting diode (140) on the ceramic substrate; a first light-transmissive resin layer (150) on the ceramic substrate to cover the light emitting diode; and a phosphor layer (155) on the first light-transmissive resin layer.