Light Emitting Element Electrode Segmentation

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Solution Overview

Problem

Existing light emitting elements experience a bias in current density distribution between electrodes, leading to higher forward voltage and inadequate uniform light emission.

Innovation Solution

A light emitting element design featuring a first electrode with extended portions and a second electrode with additional extended portions, where the fifth extended portion extends between the third and fourth extended portions to the first external connector side, ensuring even current distribution by spreading concentrated current to areas with lacking current flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the p-side electrode or n-side electrode is disposed in the center of the top face of the light emitting element with the other electrode surrounding the periphery, then the electrode structure is simplified, but the current density distribution becomes biased and forward voltage increases

Engineering Contradiction:
Improveelectrode structureVSAvoidcurrent density distribution uniformity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The electrodes are divided into multiple segments: a first external connector and second external connector instead of single centralized electrodes. Multiple extended portions (first through fifth extended portions) radiate from each external connector, segmenting the current entry points and distributing current flow across different regions of the semiconductor layer, thereby reducing current density bias while maintaining structural simplicity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the electrode structure are designed with different properties. The extended portions have varying lengths and orientations (first extended portion extends in first direction, second extended portion extends in second direction, etc.) to locally adapt to current distribution needs in different areas of the semiconductor layer, optimizing current uniformity without requiring complete structural complexity

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the electrode structure uses centralized or peripheral disposal, then manufacturing is easier, but light emission uniformity becomes inadequate

Engineering Contradiction:
Improveelectrode structure fabricationVSAvoidlight emission uniformity
Core Design Contradiction:
Ease of manufactureVSIllumination intensity

Solution Approach 1:

The electrode structure is segmented into multiple extended portions radiating from external connectors, which can be manufactured using standard photolithography and electrode deposition processes. The segmented design achieves uniform light emission by distributing current across multiple entry points without requiring complex multi-step manufacturing procedures, maintaining ease of fabrication while improving emission uniformity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The electrode structure transitions from two-dimensional centralized or peripheral disposal to a radial multi-directional configuration. The extended portions extend in different directions (first direction, second direction, third direction, fourth direction) from the external connectors, adding dimensional complexity to current distribution while maintaining planar manufacturing simplicity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP2597688B1Light emitting element
Publication Date: 2017.08.30 NICHIA CORP
  • EP2597688B1 patent drawingFigure 1
  • EP2597688B1 patent drawingFigure 2~3
  • EP2597688B1 patent drawingFigure 4a~4b

AI summary

A semiconductor light emitting element has a first electrode and a second electrode provided on a semiconductor layer; the first electrode has a first external connector and a first extended portion and second extended portion that extend from the first external connector, the second electrode has a second external connector , and a third extended portion , a fourth extended portion , and a fifth extended portion that extend from the second external connector , the third extended portion extends along the first extended portion and farther outside than the first extended portion , the fourth extended portion extends along the second extended portion and farther outside than the second extended portion , and the fifth extended portion extends an area between the third extended portion and the fourth extended portion to the first external connector side, and the fifth extended portion is either on a line that links a point on the first extended portion at the position closest to the second external connector and a point on the second extended portion at the position closest to the second external connector, or closer to the second external connector side than the line.