Light Emitting Device Electrode Placement for Current Spreading
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Solution Overview
Problem
Horizontal type light emitting devices face high current spreading resistance due to the positioning of n-electrodes and p-electrodes, which is exacerbated when multiple light emitting cells are connected in series or parallel, leading to inefficient current distribution and performance.
Innovation Solution
Optimizing the placement of the second electrode between the first and second conductivity-type semiconductor layers, specifically positioning it within a defined distance from the first side surface to enhance current spreading, and using conductive interconnection layers to connect neighboring light emitting cells, thereby improving current distribution and reducing operating voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If n-electrode and p-electrode are horizontally formed in conventional light emitting device, then device structure is simple, but current spreading resistance is high
Solution Approach 1:
The patent transitions from horizontal electrode arrangement to vertical electrode stacking, changing the spatial dimension of current flow. Multiple electrodes are arranged in vertical layers (n-electrode, p-electrode, and additional electrodes in between) rather than side-by-side horizontal placement, enabling current to spread through multiple vertical pathways and reducing resistance.
Solution Approach 2:
The patent combines multiple electrodes (n-electrode, p-electrode, and additional electrodes) into a single vertical stack structure. This merging of multiple current pathways into one integrated vertical arrangement allows current to distribute through all electrodes simultaneously, reducing overall spreading resistance while maintaining structural simplicity.
2Adaptability or versatility
If multiple light emitting cells are connected in series or parallel, then device functionality is enhanced, but current spreading resistance increases
Solution Approach 1:
The patent divides the light emitting device into multiple independent light emitting cells, each with its own vertical electrode stack. This segmentation allows each cell to function independently while maintaining low current spreading resistance within its own vertical structure, and the cells can be connected in series or parallel configurations.
Solution Approach 2:
By arranging electrodes vertically within each segmented cell rather than horizontally, the patent enables multiple cells to be connected in series or parallel without increasing current spreading resistance, as each cell maintains its own optimized vertical current pathways.
3Reliability
If electrode positions are optimized to enhance current spreading, then current distribution improves, but device structure becomes more complex
Solution Approach 1:
The patent achieves optimized current distribution by simply stacking electrodes vertically in a natural hierarchical order rather than requiring complex horizontal positioning optimizations. The vertical arrangement inherently provides multiple current pathways without needing sophisticated electrode placement calculations.
Solution Approach 2:
Instead of optimizing horizontal electrode positions to reduce spreading resistance, the patent inverts the approach by stacking electrodes vertically, allowing current to flow through multiple layers in the vertical dimension, which naturally reduces spreading resistance without complex positioning.
Data Source
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AI summary
Disclosed is a light emitting device including a substrate (110), a plurality of light emitting cells (100) separated from each other and disposed on the substrate, and a plurality of conductive interconnection layers (170) electrically connecting two neighboring light emitting cells. Each light emitting cell includes a light emitting structure (120) including a first conductivity-type semiconductor layer (122), an active layer (124) and a second conductivity-type semiconductor layer (126), a first electrode (130), a second electrode (140), and an etching area (S), and the light emitting structure further includes a first side surface (120a) and a second side surface (120b), and if a width between the first side surface and the second side surface is defined as W, the second electrode is disposed in an area between a position separated from the first side surface by 1/5 W and a position separated from the first side surface of the light emitting structure by 1/2 W.