Textured Substrate Pores for LED Light Extraction

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Solution Overview

Problem

Conventional light-emitting diodes (LEDs) face inefficiencies in light extraction due to total internal reflection, limiting their brightness and efficiency.

Innovation Solution

A light-emitting device with a textured substrate featuring micro-structures and pores is developed, where the substrate has a top surface with concavo-convex structures and an inclined surface, reducing total internal reflection and enhancing light extraction efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional flat substrate is used, then the device structure is simple, but light extraction efficiency is poor due to total internal reflection

Engineering Contradiction:

Improvesubstrate structure simplicityVSAvoidlight extraction efficiency

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The substrate surface is transformed from a flat plane to a curved surface with micro-concave and micro-convex structures. These curved surfaces scatter light and reduce total internal reflection, thereby improving light extraction efficiency while maintaining manufacturing feasibility through established texturing techniques.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The substrate is designed with a porous structure containing multiple pores distributed throughout its thickness. This porous configuration creates additional light extraction pathways and reduces internal reflection, significantly enhancing light extraction efficiency without compromising the structural integrity or manufacturability of the device.

Inventive Principle:

Principle #31Porous materials

2Loss of energy

If a textured substrate with micro-structures is used, then light extraction efficiency is improved, but the device structure becomes more complex

Engineering Contradiction:

Improvelight extraction efficiencyVSAvoidsubstrate structure complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The substrate structure is segmented into distinct regions with different texturing characteristics. The top surface contains micro-concave structures, the bottom surface contains micro-convex structures, and pores are distributed throughout the thickness. This segmentation allows each region to perform its specific function while maintaining overall structural coherence and manufacturability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The substrate combines multiple structural features (micro-concave surfaces, micro-convex surfaces, and pores) within a single component. This composite structure achieves superior light extraction performance by integrating multiple light management functions into one element, avoiding the need for separate components and reducing overall device complexity.

Inventive Principle:

Principle #40Composite materials

3Loss of energy

If pores are formed in the substrate, then light extraction is enhanced, but manufacturing precision requirements increase

Engineering Contradiction:

Improvelight extraction efficiencyVSAvoidpore formation precision

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The substrate structure is designed to self-form the pore patterns during the manufacturing process. The etching工艺 naturally creates uniformly distributed pores through self-organization mechanisms, eliminating the need for precise pre-positioning or complex alignment steps. This self-organizing behavior reduces manufacturing precision requirements while maintaining consistent light extraction performance.

Inventive Principle:

Principle #25Self-service

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

The textured substrate design improves light extraction efficiency by minimizing internal reflection and optimizing light emission through the bottom surface of the substrate, resulting in increased brightness and efficiency.

Implementation Method 1

Conventional light-emitting diodes (LEDs) face inefficiencies in light extraction due to total internal reflection

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

The principle of the LED is to transform electrical energy to optical energy by applying electrical current to the LED and injecting electrons and holes to the active layer. The combination of electrons and holes in the active layer emits light accordingly.

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS9548420B2Light-emitting device and manufacturing method thereof

Publication Date: 2017.01.17 ENNOSTAR CORP

AI summary

A light-emitting device comprises a substrate comprising a top surface; a light-emitting stack formed on a portion of the top surface of the substrate; and a plurality of pores formed in an area of the substrate, wherein the area is under another portion of the top surface where the light-emitting stack is not formed thereon.