LED Protrusion Structure With Voids for Higher Light Extraction
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Solution Overview
Problem
Conventional light emitting devices face challenges in achieving high light extraction efficiency and reliability due to limitations in the design of protrusions and semiconductor layers, which affect the growth of the first semiconductor layer and the subsequent light emission process.
Innovation Solution
A light emitting device is designed with a substrate featuring a pattern of protrusions, where each protrusion includes a first layer formed integrally with the substrate and a second layer of different material, optimized in terms of diameter, pitch, and height ratio, along with voids on the side of the protrusions, to enhance light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the protrusion diameter and pitch are optimized to increase light extraction efficiency, then the light emission is improved, but the manufacturing precision requirements increase due to the specific ratio constraints
Solution Approach 1:
The patent applies parameter changes by optimizing the ratio of protrusion diameter to pitch within a specific range (0.8 to 1.0) to maximize light extraction efficiency. This quantitative parameter optimization resolves the contradiction by establishing a precise design criterion that balances optical performance with manufacturability.
Solution Approach 2:
The patent uses partial action by providing voids in only a portion of the first semiconductor layer (corresponding to the side of the protrusion) rather than throughout the entire layer. This selective void formation improves light extraction at critical interfaces while maintaining structural integrity and reducing manufacturing complexity.
2Illumination intensity
If voids are provided in the first semiconductor layer to enhance light extraction, then light emission is improved, but the reliability may be affected due to potential structural weaknesses
Solution Approach 1:
The patent applies local quality by providing voids specifically in the first semiconductor layer at locations corresponding to the side of the protrusion, rather than uniformly throughout the structure. This localized void formation targets the regions most beneficial for light extraction while preserving structural integrity in critical areas.
Solution Approach 2:
The patent uses partial action by providing voids in only a portion of the first semiconductor layer rather than throughout the entire layer. This selective approach enhances light extraction efficiency at critical interfaces while maintaining sufficient material to ensure structural reliability.
3Illumination intensity
If the first layer height is increased to improve light extraction, then light emission is enhanced, but the device complexity increases due to additional layer optimization requirements
Solution Approach 1:
The patent applies parameter changes by optimizing the height of the first layer within a specific range (0.2 to 1.5 times the protrusion height) to maximize light extraction efficiency. This quantitative optimization resolves the complexity by establishing clear design guidelines rather than requiring trial-and-error experimentation.
Solution Approach 2:
The patent applies segmentation by dividing the protrusion structure into two distinct layers (first layer formed integrally with substrate, and second layer of different material) with different functions. This segmentation allows independent optimization of each layer's height and material properties, simplifying the overall design process.
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 optimized structure significantly improves light extraction efficiency by adjusting the protrusion pattern and void formation, leading to increased light emission and reduced absorption, thereby enhancing the overall performance of the light emitting device.
Implementation Method 1
a pattern of a plurality of protrusions protruding from the substrate... when a distance between centers of two adjacent protrusions is called a pitch, a ratio of a diameter of the protrusion to the pitch is about 0.8 to about 1.0
Implementation Method 2
the first semiconductor layer may be provided with voids in a portion of a region corresponding to a side of the protrusion
Data Source
AI summary
A light emitting device includes a substrate; a pattern of a plurality of protrusions protruding from the substrate; a first semiconductor layer provided on the substrate; an active layer provided on the first semiconductor layer; and a second semiconductor layer provided on the active layer, in which each of the protrusions includes a first layer formed integrally with the substrate and protruding from an upper surface of the base substrate; and a second layer provided on the first layer and formed of a material different from that of the first layer.