Multi-Cell LED Structure with Segmented Electrodes for Light Extraction
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Solution Overview
Problem
Existing light emitting diodes (LEDs) face issues such as light loss due to mesa etching for forming n-type electrodes, reduced reflective film efficiency due to large metal pads, and limited flexibility in chip size and position, which affect brightness and manufacturing efficiency.
Innovation Solution
A multi-cell LED structure is developed with a translucent substrate, semiconductor layers, and protective films to minimize active layer loss, allowing for flexible chip size and improved current diffusion, where unit cells are connected via metal lines and pads to enhance light extraction efficiency and reduce manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mesa etching is performed to form n-type electrode, then electrode contact is achieved, but active layer loss occurs reducing light output
Solution Approach 1:
The patent divides the electrode structure into multiple segments: the n-type electrode is formed through holes in the p-type semiconductor layer rather than requiring large-area mesa etching. This segmentation allows electrode contact while preserving the active layer in the regions between holes.
Solution Approach 2:
The patent introduces an intermediate structure where the n-type electrode contacts the n-type semiconductor layer through holes in the p-type layer, using the hole structure as an intermediary that enables contact while minimizing active layer removal.
2Reliability
If large metal pads are formed for electrode contact, then electrical connection is improved, but reflective film efficiency is reduced
Solution Approach 1:
The metal pads are segmented into multiple smaller contacts distributed across the chip surface rather than one large pad. This segmentation reduces the total area covering reflective regions while maintaining adequate electrical connection points.
Solution Approach 2:
The patent applies different properties to different regions: small metal pads are placed only where electrical connection is needed, while the surrounding areas maintain high reflectivity. This local differentiation optimizes both electrical connection and optical performance.
3Ease of manufacture
If fixed chip size is used in manufacturing, then manufacturing process is simplified, but flexibility in chip size and position is limited
Solution Approach 1:
The patent creates a universal substrate structure that can accommodate multiple unit cells with different configurations. The same basic substrate and layer structure supports various chip sizes and layouts, allowing one manufacturing process to produce multiple product variants.
Solution Approach 2:
The patent enables dynamic configuration of chip sizes and positions by allowing flexible arrangement of unit cells on the substrate. The manufacturing process can adapt to produce different chip dimensions and layouts from the same base structure.
4Adaptability or versatility
If multiple unit cells are bound together, then chip size flexibility is improved, but light output may be reduced without proper filling
Solution Approach 1:
The patent converts the potentially harmful effect of gaps between unit cells (which could reduce light output) into a beneficial feature by filling these gaps with reflective material. The gaps that might otherwise cause light loss are transformed into light-redirecting structures that improve overall light extraction.
Solution Approach 2:
Reflective material is introduced as an intermediary substance filling the spaces between unit cells. This intermediary converts stray light that would be lost in gaps into redirected light that contributes to overall light output, thereby maintaining brightness while enabling flexible multi-cell configurations.
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
The multi-cell LED structure reduces active layer loss, improves light output, and allows for flexible chip sizes and positions, increasing productivity and reducing manufacturing costs while simplifying the manufacturing process by eliminating the need for additional bonding pads.
Implementation Method 1
a reflective layer or a current diffusion layer formed on the second protection film and the second semiconductor layer
Data Source
AI summary
Disclosed is a light emitting diode having a multi-cell structure including a number of unit cells. The light emitting diode is capable of reducing light loss of the light emitting diode surface and improving light efficiency by bonding pads to be formed for contact between mesa etching regions for forming an electrode of the existing n-type semiconductor layers and p-type semiconductor layers. The light emitting diode is also capable of controlling chip size and manufacturing chips of different sizes from each other even when going through the same chip manufacturing process as the related art.