Patterned Phosphor Layer for LED Light Extraction
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Solution Overview
Problem
Conventional light emitting diodes (LEDs) face reduced light efficiency due to light being trapped inside the device instead of being emitted, primarily because of the difference in refractive index between the LED material and air, which affects the efficiency of white light realization.
Innovation Solution
A light emitting device with a phosphor layer formed in specific patterns on the LED, enhancing light extraction efficiency by allowing light to be effectively emitted, and a manufacturing method involving the formation of these patterns on the LED's surface or lateral surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional LED structure with a phosphor layer is used, then the device can emit white light, but light is trapped inside the device due to refractive index difference, reducing light efficiency
Solution Approach 1:
The phosphor layer is divided into multiple patterns (e.g., stripes, dots, or other geometric shapes) rather than being a continuous layer. This segmentation creates multiple interfaces between the phosphor layer and the LED chip, increasing the probability of light extraction and reducing total internal reflection at the planar interface.
Solution Approach 2:
The invention introduces vertical dimensionality to the phosphor layer structure by creating patterns with varying thicknesses, heights, or three-dimensional shapes. This dimensional change creates additional light extraction paths and interfaces, allowing light to escape more efficiently in multiple directions rather than being confined to a single planar interface.
2Ease of manufacture
If a uniform phosphor layer is formed on the LED, then the manufacturing process is simple, but light extraction efficiency is reduced due to total internal reflection at the planar interface
Solution Approach 1:
The phosphor layer is divided into multiple patterns (e.g., stripes, dots, or other geometric shapes) rather than being a continuous layer. This segmentation creates multiple interfaces between the phosphor layer and the LED chip, increasing the probability of light extraction and reducing total internal reflection at the planar interface.
Solution Approach 2:
The invention introduces vertical dimensionality to the phosphor layer structure by creating patterns with varying thicknesses, heights, or three-dimensional shapes. This dimensional change creates additional light extraction paths and interfaces, allowing light to escape more efficiently in multiple directions rather than being confined to a single planar 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 significantly improves light efficiency by allowing more light to be emitted externally, enabling the realization of uniform color and enhanced light extraction, suitable for various applications including mobile devices and automotive parts.
Implementation Method 1
a phosphor layer on the light emitting diode, the phosphor layer comprising patterns
Implementation Method 2
light emitted from the LED and/or excited light excited by light emitted from the LED are frequently not emitted to the outside from the light emitting device but disappear inside the light emitting device due to a difference in the refractive index between a material forming the LED and air outside the light emitting device
Data Source
AI summary
A light emitting device package includes substrate; first and second conduction members on the substrate; a light emitting diode on the substrate, the light emitting diode being electrically connected with the first and second conduction members; and a phosphor layer on the light emitting diode.