Light Emitting Device Protrusions Enhance Light Extraction

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Solution Overview

Problem

Current light emitting devices using III-V nitride semiconductors face challenges in achieving high light extraction efficiency due to limitations in the design of the semiconductor layers and support structures, which affect the overall performance and efficiency of the devices.

Innovation Solution

The light emitting device incorporates a protrusion projecting from the edge of a support member under the light emitting structure layer and a concave part recessed inward from the lateral surface of the support member, along with a channel layer and conductive support member, to enhance light extraction efficiency by improving the structural geometry and material distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional flat support member structure is used, then manufacturing is simple, but light extraction efficiency is low

Engineering Contradiction:

Improvestructural simplicityVSAvoidlight extraction efficiency

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The support member is designed with a curved lower surface instead of a flat surface. This curvature modifies the light extraction path and improves extraction efficiency by reducing total internal reflection at the interface between the semiconductor layer and support member.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention introduces vertical protrusions from the lower surface of the support member, adding a third-dimensional feature to an otherwise two-dimensional flat structure. These protrusions create additional light extraction interfaces and paths, significantly improving light extraction efficiency.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Loss of energy

If protrusions are added to support member edges, then light extraction efficiency improves, but device complexity increases

Engineering Contradiction:

Improvelight extraction efficiencyVSAvoidstructural complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The support member is segmented with discrete protrusions at its edges rather than a continuous complex structure. This segmentation allows the protrusions to be formed through straightforward manufacturing processes while providing the necessary light extraction enhancement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Protrusions are placed specifically at the edges of the support member where they most effectively improve light extraction, rather than uniformly across the entire surface. This localized approach maximizes efficiency improvement while minimizing added complexity.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8933477B2Light emitting device having protrusions from a conductive support member light emitting device package, and lighting system

Publication Date: 2015.01.13 SUZHOU LEKIN SEMICON CO LTD

AI summary

Disclosed is a light emitting device. The light emitting device includes a light emitting structure layer including a first semiconductor layer, an active layer, and a second semiconductor layer, an electrode electrically connected to the first semiconductor layer, an electrode layer under the light emitting structure layer, and a conductive support member under the electrode layer. A channel layer is between the second semiconductor layer and the electrode layer. A protrusion projected from at least one of edges of the conductive support member includes and having a rough surface.