LED Light Extraction via Segmented Semiconductor Structures

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Solution Overview

Problem

Conventional light-emitting diodes (LEDs) face challenges in achieving high current density and efficient light emission over a limited light-emitting area, which affects their light efficiency in certain applications.

Innovation Solution

The design incorporates a light-emitting device with a light-emitting stack comprising III-V group semiconductor materials, a light-absorbing layer, and a unique electrode structure where the light-emitting area has a defined region for light extraction and absorption, allowing for controlled light emission and improved efficiency by optimizing the current spreading and light extraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the light-emitting area is increased to improve light output, then the current density decreases, but the light efficiency deteriorates

Engineering Contradiction:

Improvelight outputVSAvoidlight efficiency

Core Design Contradiction:

Quantity of substanceVSLoss of energy

Solution Approach 1:

The patent applies local quality by creating distinct regions with different functions: a light-emitting region with specific semiconductor structures for light generation, and a light-absorbing region with tailored optical properties for light management. This allows different areas to be optimized for their specific purposes, maintaining high current density in the emitting region while managing overall light efficiency through the absorbing region's design.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The light-emitting device is segmented into functionally distinct regions: an active light-emitting area with semiconductor layers and injection electrodes, and a surrounding light-absorbing area with specific optical characteristics. This segmentation allows independent optimization of each region - the emitting region for high current density and the absorbing region for light extraction efficiency.

Inventive Principle:

Principle #1Segmentation

2Loss of energy

If the current density is increased to improve light efficiency, then the light-emitting area must be limited, but this restricts the overall light output

Engineering Contradiction:

Improvelight efficiencyVSAvoidlight output

Core Design Contradiction:

Loss of energyVSQuantity of substance

Solution Approach 1:

The patent transitions from a two-dimensional light-emitting surface to a three-dimensional structure by incorporating vertical layering of semiconductor materials with different bandgaps and optical properties. This dimensional change allows light to be generated and managed in multiple spatial dimensions, enabling high current density in the vertical direction while expanding light output through the horizontal absorbing region.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Loss of energy

If a light-absorbing layer is added to improve light extraction, then the device complexity increases, but this may affect manufacturing precision

Engineering Contradiction:

Improvelight extraction efficiencyVSAvoiddevice fabrication accuracy

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The patent employs composite materials by combining semiconductor layers with different optical and electrical properties, along with a light-absorbing layer having specific refractive index and absorption characteristics. This composite structure allows simultaneous optimization of light generation, transport, and extraction while maintaining manufacturability through established semiconductor fabrication techniques.

Inventive Principle:

Principle #40Composite materials

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 enables efficient light emission with a high current density over a limited area, enhancing light extraction and absorption, thereby improving the overall light efficiency and performance of the light-emitting device.

Implementation Method 1

When the first semiconductor structure is driven by a first current, the first active layer can emit a first light with a first main wavelength

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

When the second semiconductor structure is driven by a second current, the active layer of the second semiconductor structure can emit a second light with a second main wavelength

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 3

a light-absorbing layer, and a unique electrode structure where the light-emitting area has a defined region for light extraction and absorption

Methodology Applied

Scientific EffectOptical absorption: Absorption (EM radiation)

Data Source

PatentUS10700240B2Light emitting device

Publication Date: 2020.06.30 ENNOSTAR CORP

AI summary

The present disclosure provides a light-emitting device. The light-emitting device includes a light emitting area and an electrode area. The light-emitting area includes a first semiconductor structure having a first active layer and a second semiconductor structure having a second active layer. The electrode area includes an external electrode structure surrounding the second semiconductor structure in a top view. The light-emitting area has a shape of circle or polygon in the top view. When the first semiconductor structure is driven by a first current, the first active layer can emit a first light with a first main wavelength. When the second semiconductor structure is driven by a second current, the active layer of the second semiconductor structure can emit a second light with a second main wavelength.