Quantum Dot LED Packages with Getter and Barrier Layers

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Solution Overview

Problem

Existing light-emitting diode (LED) displays face challenges with quantum dot instability due to moisture, oxygen sensitivity, and high pump light intensities, which affect performance and lifespan.

Innovation Solution

The implementation of chip-scale packages with wire-bonded light-emitting diodes mounted on dielectric materials, incorporating quantum dot layers, light-scattering layers, diffusion barrier layers, and a getter to protect quantum dots from moisture and oxygen, while adjusting the conduction and valence bands using n-type and p-type dopants for enhanced performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If quantum dots are used to convert blue light to narrowband red and green light, then color saturation is enhanced, but quantum dot stability deteriorates due to moisture and oxygen sensitivity

Engineering Contradiction:

Improvecolor saturationVSAvoidquantum dot stability

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

An encapsulation layer is introduced as an intermediary between the quantum dots and the external environment. This encapsulation layer acts as a protective barrier that prevents moisture and oxygen from reaching the quantum dots, thereby maintaining their stability while allowing them to continue converting blue light to narrowband red and green light for enhanced color saturation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates an inert environment around the quantum dots by providing an encapsulation layer that excludes moisture and oxygen. This inert atmosphere protects the quantum dots from degradation while they perform their light conversion function, resolving the contradiction between maintaining stability and achieving enhanced color saturation.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Use of energy by moving object

If quantum dots are exposed to high pump light intensities, then light conversion efficiency is improved, but quantum dot lifetime is reduced

Engineering Contradiction:

Improvelight conversion efficiencyVSAvoidquantum dot lifetime

Core Design Contradiction:

Use of energy by moving objectVSDuration of action of moving object

Solution Approach 1:

The encapsulation layer provides beforehand cushioning protection to the quantum dots against the harmful effects of high pump light intensities. By shielding the quantum dots from excessive light exposure and associated thermal effects, the encapsulation layer extends their operational lifetime while still allowing sufficient light conversion efficiency to be achieved.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If quantum dots are used in display structures, then display performance is enhanced, but quantum dot performance deteriorates due to insufficient quantum confinement and instability

Engineering Contradiction:

Improvedisplay performanceVSAvoidquantum dot confinement stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent employs an encapsulation layer in the form of a thin film structure that provides mechanical protection and maintains quantum dot confinement. This flexible shell structure protects the quantum dots from structural degradation while allowing them to maintain their optical properties and contribute to enhanced display performance.

Inventive Principle:

Principle #30Flexible shells and thin films

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 enhances the stability and performance of quantum dots, improving color saturation and efficiency in LED displays by protecting them from environmental factors and optimizing energy confinement.

Implementation Method 1

a display may include red and green quantum dots to convert some of the blue light from a blue light source to narrowband red and green light

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

A getter may be incorporated into one or more of the layers to getter oxygen and water

Methodology Applied

Scientific EffectGettering: Gettering

Implementation Method 3

Layers of material may be formed over the light-emitting diodes and packages. These layers may include quantum dot layers, light-scattering layers

Methodology Applied

Scientific EffectLight scattering: Scattering

Implementation Method 4

Quantum dots may be formed from semiconductor layers that are doped with n-type and p-type dopant to adjust the locations of the conduction and valance bands in the layers of the quantum dots

Methodology Applied

Scientific EffectDoping: Dopants

Data Source

PatentUS9620686B2Display light sources with quantum dots

Publication Date: 2017.04.11 APPLE INC

AI summary

A display may be provided with light sources. The light sources may include light-emitting diodes. The light sources may have packages formed from package bodies to which the light-emitting diodes are mounted. Layers such as quantum dot layers, light-scattering layers, spacer layers, and diffusion barrier layers may be formed over the package bodies and light-emitting diodes. Quantum dots of different colors may be stacked on top of each other. A getter may be incorporated into one or more of the layers to getter oxygen and water. Quantum dots may be formed from semiconductor layers that are doped with n-type and p-type dopant to adjust the locations of their conduction and valance bands and thereby enhanced quantum dot performance.