Annular Electrode Asymmetry for LED Current Distribution

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Solution Overview

Problem

Current semiconductor light emitting devices face challenges in achieving balanced current distribution and operational voltage efficiency, leading to suboptimal luminance and voltage characteristics.

Innovation Solution

The design incorporates an annular-shaped electrode structure with asymmetrical finger configurations and auxiliary electrodes, allowing for even current spreading and reduced operational voltage by strategically positioning electrode pads and fingers to distribute current across the device surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional electrode structures are used, then device simplicity is maintained, but current distribution is uneven leading to poor luminance efficiency

Engineering Contradiction:

Improveluminance efficiencyVSAvoidelectrode structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The electrode structure is segmented into multiple components: annular electrode fingers forming a ring pattern, radial electrode fingers extending from the center, and a central electrode pad. This segmentation allows current to be distributed through multiple pathways across the semiconductor layer, achieving uniform current distribution and high luminance efficiency without excessive complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The electrode structure transitions from conventional linear or simple patterns to a two-dimensional annular configuration with radial symmetry. The annular fingers form a ring that encompasses a large area of the semiconductor layer, while radial fingers extend outward, creating a geometric pattern that maximizes current distribution across the device area, thereby improving luminance efficiency.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Power

If conventional electrode structures are used, then manufacturing processes remain simple, but operational voltage is high due to poor current spreading

Engineering Contradiction:

Improveoperational voltageVSAvoidelectrode fabrication complexity

Core Design Contradiction:

PowerVSEase of manufacture

Solution Approach 1:

While the overall pattern exhibits radial symmetry, the electrode structure incorporates asymmetric elements in its implementation. The annular fingers may have varying widths or spacing in different segments, and radial fingers can be positioned at specific angular intervals rather than uniform distribution. This controlled asymmetry optimizes current spreading pathways while maintaining manufacturability through standard photolithography processes.

Inventive Principle:

Principle #4Asymmetry

3Productivity

If electrode centers are aligned with device center, then structural symmetry is maintained, but current distribution becomes concentrated rather than evenly spread

Engineering Contradiction:

Improvecurrent distribution uniformityVSAvoidelectrode geometric symmetry

Core Design Contradiction:

ProductivityVSShape

Solution Approach 1:

Instead of concentrating electrode material at the center point, the design inverts the approach by creating an annular (ring-shaped) electrode structure that distributes material around a central region. The annular fingers form a continuous ring that encircles the central area, forcing current to spread radially outward through multiple pathways rather than concentrating at the center, thereby achieving uniform current distribution across the semiconductor layer.

Inventive Principle:

Principle #13The other way round (Inversion)

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 configuration enhances luminance efficiency and operational voltage characteristics by ensuring even current distribution and reducing voltage requirements, thereby improving the overall performance of semiconductor light emitting devices.

Implementation Method 1

The first electrode unit is disposed on an upper surface of the light emitting structure, connected to the first conductivity-type semiconductor layer... The second electrode unit is disposed on the upper surface of the light emitting structure, connected to the second conductivity-type semiconductor layer

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

Semiconductor light emitting devices emit light through the recombination of electrons and holes when a current is applied thereto

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS9070834B2Semiconductor light emitting device

Publication Date: 2015.06.30 SAMSUNG ELECTRONICS CO LTD

AI summary

A semiconductor light emitting device includes a light emitting structure, a first electrode unit, and a second electrode unit. The light emitting structure includes a first and second conductivity-type semiconductor layer, an active layer. The first electrode unit includes a first electrode pad and a first electrode finger extending from the first electrode pad, and having an annular shape with an open portion. The second electrode unit includes a second electrode pad and a second electrode finger extending from the second electrode pad, and has an annular shape with an open portion. One of the first and second electrode units substantially surrounds the other, and the center of the annular shape of at least one of the first and second electrode units is spaced apart from the center of the upper surface of the light emitting structure.