III-Nitride LED Array with Tunnel Junctions for VLC

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Solution Overview

Problem

The manufacturing of micro-LED displays with high resolution is hindered by the complexity and cost of aligning and attaching small LEDs of different wavelengths, which requires intricate and time-consuming pick and place operations, and current methods face challenges in achieving independent control of wavelength and radiance, leading to poor color purity and high forward voltage.

Innovation Solution

A multiple quantum well LED array is developed, where multiple LEDs emitting different wavelengths are integrated on a single substrate with tunnel junctions and independent electrical contacts, allowing for independent control of light emission and reducing the number of epitaxial growth runs and pick and place operations, while avoiding the issues of making ohmic contacts to etched p-GaN surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If separate blue, green and red LEDs are picked and placed in close proximity to form high-resolution displays, then color display capability is improved, but manufacturing complexity and cost increase significantly

Engineering Contradiction:

Improvecolor display capabilityVSAvoidmanufacturing complexity

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The patent combines multiple wavelength LEDs (blue, green, red) into a single integrated LED structure with multiple quantum well layers, eliminating the need for separate pick-and-place operations for each color LED while maintaining high-resolution color display capability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The integrated LED structure performs multiple functions simultaneously - emitting blue, green, and red light from a single device, and provides both display functionality and visible light communication capability through the same structure

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Manufacturing precision

If uLED size is decreased to improve resolution, then display resolution is improved, but pick and place operation difficulty increases

Engineering Contradiction:

Improvedisplay resolutionVSAvoidpick and place operation difficulty

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

By integrating multiple wavelength LEDs into a single larger-footprint device, the patent eliminates the need for precise pick-and-place operations on individual sub-50um uLEDs, while still achieving high resolution through the integrated structure's multiple emission wavelengths

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If multiple quantum wells are used to emit different wavelengths, then wavelength control is improved, but independent control of radiance becomes difficult

Engineering Contradiction:

Improvewavelength controlVSAvoidindependent radiance control

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent segments the integrated LED into distinct blue, green, and red emitting regions with separate electrical contacts, allowing independent current control to each wavelength region while maintaining the integrated structure's manufacturing advantages

Inventive Principle:

Principle #1Segmentation

4Ease of manufacture

If conventional LED structures are used, then manufacturing is simpler, but forward voltage is high and efficiency is poor

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidforward voltage

Core Design Contradiction:

Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The patent optimizes the quantum well structure parameters, barrier layer compositions, and doping profiles to reduce forward voltage and improve efficiency while maintaining the integrated multi-wavelength capability, achieving better energy efficiency than conventional separate LED structures

Inventive Principle:

Principle #35Parameter changes

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 approach reduces the number of epitaxial growth runs and pick and place operations, lowers the operating voltage, and enhances the efficiency and throughput of micro-LED display manufacturing, enabling more efficient and cost-effective production of high-resolution displays with improved color control.

Implementation Method 1

The first pixel and the second pixel may include one or more tunnel junctions on one or more LEDs

Methodology Applied

Scientific EffectTunnel junction:

Data Source

PatentUS11594572B2III-nitride multi-wavelength LED for visible light communication

Publication Date: 2023.02.28 LUMILEDS SINGAPORE PTE LTD

AI summary

A light emitting diode (LED) array may include a first pixel and a second pixel on a substrate. The first pixel and the second pixel may include one or more tunnel junctions on one or more LEDs. The LED array may include a first trench between the first pixel and the second pixel. The trench may extend to the substrate.