LED Current Blocking Layer for Uniform Light Output
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Solution Overview
Problem
Current light emitting diodes (LEDs) face challenges in preventing current concentration on side surfaces, which affects light quantity and efficiency, and require complex fabrication processes due to material defects and mismatched contact forces between passivation layers and light emitting structures.
Innovation Solution
The implementation of a current blocking layer at the peripheral side of the semiconductor layers and a passivation layer formed from the same series material as the light emitting structure, using selective region growth methods to reduce crystal defects and enhance current spreading, thereby improving internal efficiency and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional LED structure is used, then the device is simple to manufacture, but current concentration occurs on side surfaces reducing light quantity and efficiency
Solution Approach 1:
The patent applies local quality by creating a current blocking layer with specific spatial distribution - positioned at the peripheral side of the light emitting structure rather than uniformly throughout. This localized placement blocks current at the edges where concentration occurs, while maintaining normal current flow in the central region, thus achieving uniform current distribution and improved light quantity without compromising manufacturing simplicity
2Ease of manufacture
If different materials are used for passivation layer and light emitting structure, then contact force may be optimized, but material defects and mismatched contact forces increase fabrication complexity
Solution Approach 1:
The patent applies homogeneity by forming the passivation layer from the same series material as the light emitting structure. This material compatibility eliminates defects arising from material mismatches and ensures matched contact forces between layers, simplifying the fabrication process while maintaining reliable electrical and mechanical contact
3Reliability
If crystal defects are present in the light emitting structure, then the fabrication process is simpler, but internal efficiency and reliability decrease
Solution Approach 1:
The patent applies preliminary action by implementing selective region growth methods during the fabrication process to prevent crystal defects from forming in the first place. By controlling the growth conditions and sequence - growing the light emitting structure with optimized parameters before adding the passivation layer - the method reduces crystal defects proactively, achieving high internal efficiency without requiring complex post-processing or repair steps
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 approach prevents current concentration, increases light quantity, simplifies the fabrication process, and enhances the contact force between the passivation layer and the light emitting structure, resulting in high internal efficiency and reliability of the LEDs.
Implementation Method 1
a first conductivity type semiconductor layer disposed on the active layer while including a current blocking layer at a periphery side thereof
Implementation Method 2
a passivation layer disposed over the light emitting structure
Implementation Method 3
A light emitting diode (LED) is a semiconductor device that converts an electrical signal into light
Data Source
AI summary
A light emitting device includes a first electrode, a first semiconductor layer, an active layer; a second semiconductor layer, and a second electrode. A current blocking layer is formed on a side surface of and has a width provided within the first semiconductor layer. The thickness and width of the current blocking layer is smaller than the thickness and width of the first semiconductor layer.