LED Pillar Array for Light Extraction and Current Spreading
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Solution Overview
Problem
Current light-emitting diodes face challenges in enhancing lighting efficiency and light-extraction efficiency, which are crucial for achieving high functional reliability and low power consumption in various applications.
Innovation Solution
The design includes a substrate with a first conducting-type semiconductor layer, plural pillars, a transparent insulating material, a light-emitting layer, a second conducting-type semiconductor layer, a first transparent conducting layer, and a second transparent conducting layer, where the pillars are formed on the substrate and the transparent insulating material is filled between them, reducing total reflection and enhancing anti-destruction strength, and the transparent conducting layers are coated on the pillars to improve current-spreading and uniform illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional planar structure is used, then fabrication is simple, but light-extraction efficiency is low
Solution Approach 1:
The patent divides the planar semiconductor layer into multiple vertical pillars arranged in an array. This segmentation creates multiple light-extraction interfaces and paths, significantly improving light-extraction efficiency while maintaining fabrication simplicity through standard semiconductor processing techniques.
Solution Approach 2:
The patent transitions from a two-dimensional planar structure to a three-dimensional pillar array structure. This dimensional change increases the surface area for light extraction and creates multiple extraction paths, thereby improving light-extraction efficiency without complicating the fabrication process.
2Loss of energy
If high refractive index material is used to improve light extraction, then light-extraction efficiency increases, but total reflection increases
Solution Approach 1:
The patent uses vertical pillar structures with curved surfaces instead of flat planes. The curved surfaces of the pillars reduce total internal reflection by providing gradual refractive index transitions and multiple extraction angles, allowing high refractive index materials to improve light extraction without excessive reflection losses.
3Device complexity
If current is concentrated in small area, then device structure is simple, but illumination uniformity is poor and instant discharge occurs
Solution Approach 1:
The patent segments the current path into multiple vertical pillars, distributing the current across many parallel conduction paths. This segmentation improves illumination uniformity and prevents instant discharge while maintaining relatively simple device structure through straightforward electrode design.
Solution Approach 2:
The patent extends the current distribution from a two-dimensional plane to a three-dimensional pillar array. This dimensional expansion allows current to spread vertically through multiple pillars, improving illumination uniformity across the light-emitting surface while maintaining structural simplicity.
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 increases light-extraction efficiency, reduces total reflection, enhances the structural integrity of the diode, and ensures better current-spreading and uniform illumination, leading to improved performance and reliability.
Implementation Method 1
the transparent insulating material filled in the gaps between the pillars not only reduces the total reflection of light inside the light-emitting diode
Implementation Method 2
The internal quantum efficiency is determined by the material property and quality. The light-extraction efficiency refers to the proportion of radiation emitted from the interior of the device the device into surrounding air or encapsulating epoxy.
Data Source
AI summary
The invention discloses a light-emitting diode which comprises a substrate, a first conducting-type semiconductor layer, plural pillars, a transparent insulating material, an illuminating layer, a second conducting-type semiconductor layer, a first transparent conducting layer and a second transparent conducting layer. The first conducting-type semiconductor layer is formed on the substrate, and the top surface of the first conducting-type semiconductor layer comprises a first region and a second region surrounded by the first region. The pillars are formed on the first region. The transparent insulating material is filled in the gaps between the pillars to be as high as the pillars. The illuminating layer is formed on the second region, and the second conducting-type semiconductor layer is formed on the illuminating layer. The first transparent conducting layer is formed on the second conducting-type semiconductor layer, and the second transparent conducting layer is formed on a top surface of the pillars and the transparent insulating material.