LED Edge Lump Interconnection for Stable Electrical Contact

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Solution Overview

Problem

Conventional light emitting diodes (LEDs) with multi-cell structures on a single substrate suffer from short lifetime and low luminous efficiency due to defective interconnection layers at the edge portions, leading to poor electrical connections and increased resistance.

Innovation Solution

The implementation of a light emitting diode design with a continuous passivation layer and an interconnection layer that includes an edge lump portion around the edges of the light emitting cells, where the edge lump portion protrudes and has a larger thickness than the normal interconnection layer, ensuring stable electrical connections and preventing sagging during deposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the interconnection layer is formed by conventional deposition processes, then the manufacturing process is simple and cost-effective, but the edge portions of the interconnection layer are insufficiently deposited leading to reduced thickness and poor electrical connection

Engineering Contradiction:

Improvethickness uniformity of interconnection layerVSAvoidcomplexity of deposition process

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

A protrusion structure is formed at the edge portion of the light emitting cell before the interconnection layer is deposited. This preliminary structural modification ensures that the interconnection layer is sufficiently deposited at the edge portions, preventing thickness reduction and maintaining good electrical connection without requiring complex deposition process adjustments

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protrusion structure is specifically formed only at the edge portions where thickness deficiency occurs, rather than uniformly across the entire surface. This localized modification targets the specific problem area, improving thickness uniformity where needed while maintaining simplicity in the overall manufacturing process

Inventive Principle:

Principle #3Local quality

2Reliability

If the interconnection layer thickness is reduced at edge portions, then the manufacturing process remains simple, but the resistance increases and heat generation occurs leading to electrical disconnection

Engineering Contradiction:

Improveelectrical connection stabilityVSAvoidsimplicity of deposition process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The protrusion structure is formed in advance at the edge portions before interconnection layer deposition. This preliminary action ensures sufficient material deposition at critical edge areas, preventing thickness reduction that would lead to high resistance and electrical disconnection, while keeping the deposition process itself simple and straightforward

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protrusion structure acts as a cushioning feature that compensates for potential deposition deficiencies at edge portions. By providing this extra structural support beforehand, the design prevents the harmful effects of thickness reduction (high resistance, heat generation, electrical disconnection) before they can occur during normal operation

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 design enhances the electrical connectivity and luminous efficiency of the LEDs by maintaining the thickness of the interconnection layer around the edges, preventing heat generation and interconnection failures, thus extending the lifespan and improving performance.

Implementation Method 1

The interconnection layer 32 is formed, for example, by a deposition process, such as sputtering or e-beam evaporation

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Data Source

PatentUS10283687B2Light emitting diode

Publication Date: 2019.05.07 LUMENS CO LTD

AI summary

A light emitting diode is disclosed. The light emitting diode includes: a plurality of light emitting cells including a first light emitting cell and a second light emitting cell spaced apart from each other on a single substrate; a continuous passivation layer formed over the upper surface and one facet of the first light emitting cell, the upper surface and the other facet of the second light emitting cell, and the substrate; and an interconnection layer formed on the passivation layer to electrically connect the first light emitting cell to the second light emitting cell. The interconnection layer includes an edge lump portion formed around a first edge where the upper surface and the one facet of the first light emitting cell meet each other or a second edge where the upper surface and the other facet of the second light emitting cell meet each other. The edge lump portion protrudes in a direction away from the edge.