Light Emitting Device Electrode Texture for Light Extraction
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Solution Overview
Problem
Light emitting devices face reduced efficiency due to light absorption and reflection by electrodes, and current crowding issues that shorten their lifespan and degrade reliability.
Innovation Solution
A light emitting device structure with a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer, featuring a texture on one region and a pad electrode on another region without texture, to minimize light absorption and enhance current spreading by adjusting contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat electrode structure is used, then the manufacturing process is simple, but light absorption and reflection by the electrode reduce light extraction efficiency
Solution Approach 1:
The patent applies local quality by creating a textured surface structure only in specific regions where light extraction needs improvement, while maintaining flat electrode areas where electrical contact is critical. This localized texturing allows the electrode to simultaneously achieve good light extraction efficiency in textured regions and maintain simple electrical connection in flat regions, resolving the contradiction between manufacturing simplicity and light extraction performance.
2Power
If current is concentrated in a small area, then the electrical connection is efficient, but current crowding occurs which shortens device lifespan and degrades reliability
Solution Approach 1:
The patent segments the electrode contact area into multiple regions with different surface characteristics. By dividing the contact area and creating various texture patterns in different zones, the current distribution is spread out rather than concentrated in one spot. This segmentation approach maintains efficient electrical connection while preventing current crowding, thereby improving device reliability and lifespan.
Solution Approach 2:
The patent introduces surface texture dimensions to the otherwise two-dimensional electrode contact area. By adding vertical surface features (textures) to the flat electrode plane, it creates three-dimensional current pathways that distribute current more evenly across the contact area, preventing current crowding while maintaining electrical efficiency.
3Ease of manufacture
If the electrode surface is made uniform, then the manufacturing process is straightforward, but light absorption reduces the light emitting efficiency
Solution Approach 1:
The patent implements local quality by applying different surface treatments to different regions of the electrode. Some areas maintain uniform flat surfaces for simple manufacturing and good electrical contact, while other regions receive texturing treatment to enhance light extraction. This localized differentiation allows the device to achieve high light emitting efficiency without significantly complicating the overall manufacturing 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
Improves light extraction efficiency and current spreading, reducing absorption in pad electrodes and preventing current crowding, thereby extending the device's lifespan and enhancing reliability.
Implementation Method 1
a first texture over a first region of the first conductive semiconductor layer
Implementation Method 2
a part of light generated from the active layer is absorbed or reflected by an electrode, thereby causing loss in the light emitting device
Implementation Method 3
adjusting contact resistance
Data Source
AI summary
Disclosed are a light emitting device, a light emitting device package and a lighting system. The light emitting device of the embodiment includes a light emitting structure including a first conductive semiconductor layer, a second conductive semiconductor layer and an active layer between the first and second conductive semiconductor layers; a second electrode under the second conductive semiconductor layer; a first texture over a first region of the first conductive semiconductor layer; an A-electrode over the first region of the first conductive semiconductor layer; and a B-electrode over a second region of the first conductive semiconductor layer, wherein the B-electrode includes a pad electrode connected to a wire.