Distributed-Bragg Reflecting Layer for LED Light Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional LED lighting devices face issues with low reflectivity, especially in the UV band, and light absorbance due to metal reflecting layers, which also complicates manufacturing processes due to sensitivity to vapor deposition conditions.
Innovation Solution
A high efficiency lighting device is developed using a distributed-Bragg reflecting layer (DBR) with alternating high and low refractive index layers and a micro-contact layer array, attached via vapor deposition, to enhance reflectivity and heat dissipation, replacing conventional metal reflecting layers and eutectic binding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a metal reflecting layer (titanium and aluminum) is used to reduce light attenuation, then light reflection is improved, but reflectivity is insufficient especially in the UV band and the structure becomes complex with multiple layers
Solution Approach 1:
The patent extracts and removes the complex multi-layer metal reflecting structure (titanium layer 120, aluminum layer 130, gold/tin alloy layer 140) and replaces it with a simplified single-layer dielectric mirror layer 230 having high reflectivity across the UV-visible spectrum, thereby reducing structural complexity while maintaining or improving light reflection performance
Solution Approach 2:
The patent employs a dielectric mirror layer composed of alternating high-refractive-index and low-refractive-index dielectric materials, creating a composite structure that achieves superior broadband reflectivity (including UV band) compared to conventional metal layers, while simplifying the overall device architecture
2Productivity
If a metal reflecting layer is used to increase lighting efficiency, then light attenuation is reduced, but manufacturing precision becomes difficult to control due to sensitivity to vapor deposition conditions
Solution Approach 1:
The patent transitions from metal-based reflecting layers to dielectric-based mirrors, fundamentally changing the material parameter (from metallic to dielectric). This enables control through dielectric layer thickness and refractive index ratios rather than metal deposition parameters, significantly improving manufacturing precision and reducing sensitivity to vapor deposition conditions
Solution Approach 2:
The dielectric mirror layer can be formed using standard semiconductor fabrication processes with well-controlled deposition parameters, replacing the sensitive metal vapor deposition process. This allows for more robust and repeatable manufacturing with better process windows and less sensitivity to deposition condition variations
3Illumination intensity
If conventional metal reflecting layers are used, then light reflection is achieved, but light absorbance increases and lighting efficiency decreases
Solution Approach 1:
The patent converts the inherently absorptive nature of metals into a beneficial low-absorption dielectric structure. By using alternating high/low refractive index dielectric layers, the design achieves high reflectivity through constructive interference while minimizing absorption losses, as dielectric materials inherently absorb less light than metals across the UV-visible spectrum
Solution Approach 2:
The dielectric mirror uses composite dielectric materials with alternating refractive indices to achieve high reflectivity through optical interference effects rather than metal reflection. This composite structure minimizes light absorbance while maintaining or enhancing light reflection efficiency compared to conventional metal layers
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 DBR layer achieves reflectivity above 90% and significantly increases light extraction and heat dissipation efficiency, overcoming the limitations of conventional metal reflecting layers, including improved performance in the UV band and more stable manufacturing processes.
Implementation Method 1
a distributed-Bragg reflecting layer (DBR) for increasing the extraction efficiency thereof
Implementation Method 2
multiple high refraction layers and low refraction layers in an alternating manner, so as to form a stacked thin film having an alternate high/low refraction pattern
Implementation Method 3
attaching a distributed-Bragg reflecting layer (DBR) to the light emitting diode structure by vapor deposition
Implementation Method 4
the distributed-Bragg reflector layer has a micro-contact layer array to increase the heat dissipating efficiency of the lighting device
Data Source
AI summary
A high efficiency lighting device comprising a light emitting diode structure, an eutectic layer and a distributed-Bragg reflecting layer (DBR) therebetween is disclosed. The distributed-Bragg reflecting layer is attached to said light emitting diode structure by vapor deposition and comprises a plurality of high refraction layers, a plurality of low refraction layers and a micro-contact layer array. The high refraction layers and said low refraction layers are arranged in an alternating manner, so as to form a stacked thin film having an alternate high/low refraction pattern. The micro-contact layers are in said stacked thin film and extend vertically through the stacked thin film, therefore connecting said light emitting diode structure and said eutectic layer.