LED Mesa Reflector and Radial Electrode Layout for Light Extraction
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Solution Overview
Problem
Conventional light-emitting diodes (LEDs) face challenges in maximizing light extraction efficiency due to limitations in reflective structures and electrode designs, which affect the forward voltage and light-emitting area.
Innovation Solution
The design incorporates a reflective structure with varying thicknesses and shapes to enhance light extraction, along with a flip chip structure featuring extending electrodes with different widths and contact areas, and a Distributed Bragg Reflector (DBR) structure to optimize light reflection and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional reflective structure with uniform thickness is used, then the manufacturing process is simple, but the light extraction efficiency is limited
Solution Approach 1:
The reflective structure employs varying thickness across different regions - a first thickness in the first region and a second thickness greater than the first thickness in the second region. This local variation optimizes light reflection and extraction efficiency in different areas of the LED device, resolving the contradiction between manufacturing simplicity and light extraction performance.
2Reliability
If the electrode contact area is increased, then the electrical connection is improved, but the light-emitting area is reduced
Solution Approach 1:
The extending electrode is designed to extend in the radial direction from the center of the light-emitting device toward the edge, utilizing the radial dimension to achieve both objectives. The electrode extends radially to maintain electrical connection while being positioned to minimize impact on the central light-emitting area, thus resolving the contradiction between electrical connection reliability and light-emitting area.
3Reliability
If the extending electrode width is increased, then the electrical connection is improved, but the light extraction efficiency is reduced
Solution Approach 1:
The extending electrode features a first width in the first region and a second width greater than the first width in the second region. This local variation in width optimizes the balance between electrical connection (achieved through sufficient electrode width) and light extraction efficiency (maintained by limiting electrode width in critical light-emitting regions), resolving the contradiction between these two parameters.
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 improves light extraction efficiency, reduces forward voltage, and increases the light-emitting area, leading to enhanced performance and efficiency in LED devices.
Implementation Method 1
a first reflective structure comprising a first reflective portion covering the first sidewall and a second reflective portion covering the second sidewall
Implementation Method 2
a Distributed Bragg Reflector (DBR) structure to optimize light reflection and distribution
Data Source
AI summary
A light-emitting device comprises a first semiconductor layer and a semiconductor mesa formed on the first semiconductor layer, wherein the first semiconductor layer comprises a first sidewall and a first semiconductor layer first surface surrounding the semiconductor mesa, and the semiconductor mesa comprises a second sidewall; and a first reflective structure comprising a first reflective portion covering the first sidewall and a second reflective portion covering the second sidewall, wherein the first reflective portion and the second reflective portion are connected to form a first reflective structure outer opening to expose the first semiconductor layer first surface in a top view of the light-emitting device.