Flexible GaN Nanostructure Light Emitters for High-Contrast Displays

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Solution Overview

Problem

Current GaN-based light emitting diodes (LEDs) face limitations in high-resolution and high-contrast displays due to their rigidness and inefficiency, particularly when used for backlighting in LCDs, as they either increase display thickness or fail to enhance contrast.

Innovation Solution

The development of thin, flexible, and efficient light emitting structures using semiconductor nanostructures transferred from their host substrate to a new matrix, such as SiN x or SiO 2, allowing for improved electrical, thermal, and optical characteristics, enabling high-resolution, high-contrast, and low-power displays and lighting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If GaN-based LEDs are placed directly behind the display for backlighting, then contrast is improved, but display thickness increases and manufacturing cost increases

Engineering Contradiction:
Improvedisplay contrastVSAvoiddisplay thickness
Core Design Contradiction:
Illumination intensityVSLength of stationary object

Solution Approach 1:

The patent extracts the light-emitting function from traditional rigid GaN-based LEDs by transferring GaN nanostructures from their original substrate to a flexible polymer substrate. This separation allows the light-emitting elements to be applied directly to the display surface, improving contrast while maintaining thin display profile

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a flexible polymer substrate to carry the transferred GaN nanostructures, creating a thin-film light-emitting layer that can be directly integrated into the display structure without adding significant thickness, thus resolving the contradiction between contrast improvement and thickness control

Inventive Principle:
Principle #30Flexible shells and thin films

2Illumination intensity

If conventional GaN-based LEDs are used for backlighting, then lighting function is provided, but manufacturing complexity and cost increase due to additional layers and structures

Engineering Contradiction:
Improvebacklighting functionVSAvoidmanufacturing complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent extracts only the essential light-emitting GaN nanostructures from the complex conventional LED structure, transferring them to a simple flexible polymer substrate. This eliminates the need for complex current distribution layers and other LED components, simplifying manufacturing while maintaining backlighting function

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces expensive and complex conventional LED structures with a simpler, more cost-effective solution using transferred GaN nanostructures on flexible substrate, reducing manufacturing complexity and cost while achieving the same backlighting function

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Length of stationary object

If GaN-based LEDs are used on edge with waveguiding, then display thickness is reduced, but contrast improvement is limited for high-resolution displays

Engineering Contradiction:
Improvedisplay thicknessVSAvoiddisplay contrast
Core Design Contradiction:
Length of stationary objectVSIllumination intensity

Solution Approach 1:

Instead of placing LEDs on the edge and using waveguiding to distribute light, the patent inverts the approach by transferring light-emitting GaN nanostructures directly to the display surface where they provide localized backlighting, achieving both thin profile and high contrast for high-resolution displays

Inventive Principle:
Principle #13The other way round (Inversion)

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 enables the manufacture of high-quality, thin GaN-based light emitters with reduced defect density, allowing for high-resolution displays and efficient lighting without the need for current distribution layers like ITO, resulting in improved performance and cost-effectiveness.

Implementation Method 1

semiconductor nanostructures transferred from their host substrate to a new matrix

Methodology Applied
Scientific EffectTransfer:

Implementation Method 2

GaN-based light emitting diodes (LEDs)

Methodology Applied
Scientific EffectLight emitting diode effect: Light Emitting Diode

Implementation Method 3

light emitting structures

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3138134B1Thin flexible light emitting diodes and method for their fabrication
Publication Date: 2020.04.15 SARKISSIAN RAYMOND
  • EP3138134B1 patent drawingFigure 1
  • EP3138134B1 patent drawingFigure 2
  • EP3138134B1 patent drawingFigure 3

AI summary

A light emitting structure may include a light emitting element(s) arranged in a transparent dielectric material. The light emitting element(s) may include a semiconductor nanostructure arranged in a display orientation different from a growth orientation of the semiconductor nanostructure. The light emitting element(s) may also include a well layer on the semiconductor nanostructure. The light emitting element(s) may further include a capping layer on the well layer. The light emitting structure may also include a contact layer coupled to the light emitting element(s).