LED Package Layered Scattering for Light Extraction
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Solution Overview
Problem
Current light emitting device packages face inefficiencies in light extraction due to total reflection phenomena at the interfaces between the light emitting device, encapsulant, and air space, limiting the escape of photons and thus the overall light extraction efficiency.
Innovation Solution
Incorporating a first scattering agent closer to the light emitting device and a second scattering agent or phosphor on a different layer within the encapsulant, with varying specific gravities to form distinct layers, which reduces total reflection and enhances light extraction by scattering and wavelength conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a single scattering agent is used in the encapsulant, then light scattering is improved, but light extraction efficiency remains insufficient due to total reflection at interfaces
Solution Approach 1:
The encapsulant is divided into multiple layers with different scattering agents (first scattering agent in lower layer, second scattering agent or phosphor in upper layer) to progressively scatter light at different depths, increasing the probability of photon escape before total reflection occurs at any single interface
Solution Approach 2:
Different scattering agents are placed at different locations within the encapsulant - the first scattering agent is positioned closer to the light emitting device in the lower layer, while the second scattering agent or phosphor is positioned in the upper layer, creating localized scattering zones that optimize light extraction at each interface
2Illumination intensity
If phosphor is added to convert wavelength, then color reproduction is improved, but light extraction efficiency may be reduced due to additional absorption
Solution Approach 1:
The encapsulant is segmented into layers with phosphor positioned in the upper layer rather than mixed throughout, reducing the path length of light through phosphor material and minimizing absorption losses while still achieving effective wavelength conversion for improved color reproduction
Solution Approach 2:
The second scattering agent acts as an intermediary between the light emitting device and phosphor, scattering light to increase the probability of photon escape before it reaches the phosphor layer, thereby reducing the chance of light being absorbed by phosphor while still maintaining effective wavelength conversion
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
This configuration significantly improves light extraction efficiency by reducing light absorption and reflection, allowing more photons to escape into the air space, thereby enhancing the brightness and energy efficiency of the light emitting device package.
Implementation Method 1
a first material mixed with the encapsulant to scatter light emitted from the light emitting device or convert a wavelength
Implementation Method 2
a first material mixed with the encapsulant to scatter light emitted from the light emitting device or convert a wavelength
Implementation Method 3
a second material mixed with the encapsulant, and disposed on a layer different from that of the first material in the encapsulant to scatter or wavelength-convert at least part of light scattered and wavelength-converted from the first material
Implementation Method 4
a second material mixed with the encapsulant, and disposed on a layer different from that of the first material in the encapsulant to scatter or wavelength-convert at least part of light scattered and wavelength-converted from the first material
Data Source
AI summary
A light emitting device package including a light emitting device; an encapsulant configured to cover the light emitting device; a first material mixed with the encapsulant to scatter light emitted from the light emitting device or convert a wavelength; and a second material mixed with the encapsulant, and disposed on a layer different from that of the first material in the encapsulant to scatter or wavelength-convert at least part of light scattered and wavelength-converted from the first material.