Annular Finger Electrode for Uniform Current Distribution in LED
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Solution Overview
Problem
Current semiconductor light emitting devices face issues with current concentration at the finger electrode, leading to reduced electrostatic discharge tolerance and light extraction efficiency.
Innovation Solution
The semiconductor light emitting device features first and second conductivity type semiconductor layers with active layers in between, and electrodes with pad and finger parts where the finger parts have an annular shape with a hollow internal area, reducing current concentration and enhancing electrostatic discharge tolerance and light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a finger part electrode structure is used to apply uniform current, then current distribution is improved, but current concentration still occurs in portions of the finger part
Solution Approach 1:
The electrode is divided into multiple finger parts that extend from the pad part toward the light emitting area. Each finger part acts as an independent current path, segmenting the current flow to prevent concentration at single points. This segmentation allows current to distribute more uniformly across the light emitting area while maintaining electrostatic discharge tolerance through multiple parallel paths.
Solution Approach 2:
The electrode structure employs different geometries at different locations: a pad part with larger area for current input and finger parts with narrower widths for current distribution. The finger parts are positioned to target specific regions of the light emitting area, creating local current density optimization. This local quality approach ensures uniform current distribution without causing concentration at electrode edges or centers.
2Device complexity
If current is concentrated in a portion of the finger part, then electrode structure is simplified, but electrostatic discharge tolerance is reduced
Solution Approach 1:
The electrode is divided into multiple finger parts that extend from the pad part toward the light emitting area. Each finger part acts as an independent current path, segmenting the current flow to prevent concentration at single points. This segmentation allows current to distribute more uniformly across the light emitting area while maintaining electrostatic discharge tolerance through multiple parallel paths.
Solution Approach 2:
The electrode geometry parameters are optimized by adjusting the width, length, and spacing of the finger parts. The finger parts have narrower widths than the pad part, creating a gradual transition that distributes current effectively. By changing these geometric parameters, the electrode achieves both simplified structure and improved electrostatic discharge tolerance through controlled current distribution.
3Ease of manufacture
If current concentration occurs at the finger electrode, then light extraction efficiency is reduced, but electrode design becomes simpler
Solution Approach 1:
The electrode is divided into multiple finger parts that extend from the pad part toward the light emitting area. Each finger part acts as an independent current path, segmenting the current flow to prevent concentration at single points. This segmentation allows current to distribute more uniformly across the light emitting area while maintaining electrostatic discharge tolerance through multiple parallel paths.
Solution Approach 2:
The electrode structure employs different geometries at different locations: a pad part with larger area for current input and finger parts with narrower widths for current distribution. The finger parts are positioned to target specific regions of the light emitting area, creating local current density optimization. This local quality approach ensures uniform current distribution without causing concentration at electrode edges or centers.
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 current spreading, increases electrostatic discharge tolerance, and enhances light extraction efficiency by minimizing current concentration at specific areas.
Implementation Method 1
A light emitting diode, a type of semiconductor light emitting device, is a semiconductor device capable of generating light in various colors according to the recombination of electrons and holes at p and n type semiconductor junction parts when current is applied thereto
Data Source
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AI summary
A semiconductor light emitting device includes: first and second conductive type semiconductor layers; an active layer (103) disposed between the first and second conductive type semiconductor layers; and first and second electrodes disposed on one surface of each of the first and second conductive type semiconductor layers, respectively, wherein at least one of the first and second electrodes includes a pad part (106a,107a) and a finger part (106b,107b) formed to extend from the pad part, and the end of the finger part has an annular shape. Because a phenomenon in which current is concentrated in a partial area of the finger part is minimized, tolerance to electrostatic discharge (ESD) can be strengthened and light extraction efficiency can be improved.