Quantum Dot LED Package Structure for Moisture Barrier Reliability

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Solution Overview

Problem

The existing chip scale package structures for light-emitting devices using quantum dot materials face challenges in maintaining emitting efficiency due to moisture and oxygen penetration, which affects the quantum dot properties.

Innovation Solution

A light-emitting device package structure is developed, featuring a covering structure with a depressed part, where the quantum dot material block is filled and enclosed by the light-emitting element and the covering structure, effectively blocking moisture and oxygen.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If quantum dot material is used to achieve wide color gamut (100% NTSC), then color gamut is improved, but emitting efficiency deteriorates due to moisture and oxygen penetration

Engineering Contradiction:

Improvecolor gamutVSAvoidemitting efficiency

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The package structure is segmented into multiple functional layers: a light-emitting element layer, a quantum dot material layer, and a covering structure layer. This segmentation allows each layer to perform its specific function while protecting the quantum dot material from environmental degradation, thereby maintaining both wide color gamut and high emitting efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs a simple yet effective covering structure that provides sufficient protection against moisture and oxygen penetration. The covering structure acts as a barrier layer that is optimized for its protective function rather than using complex multi-layer encapsulation, achieving reliable protection while simplifying the overall package design.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Ease of manufacture

If conventional package structure is used, then manufacturing is simple, but moisture and oxygen penetration reduces quantum dot performance

Engineering Contradiction:

Improvepackage structure simplicityVSAvoidmoisture and oxygen penetration

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The covering structure functions as a protective thin film or shell that encapsulates the quantum dot material. This covering structure provides an effective barrier against moisture and oxygen penetration while maintaining a simple and manufacturable design, protecting the quantum dot properties without adding excessive structural complexity.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The package structure combines different materials with complementary properties: the light-emitting element material, the quantum dot material with specific optical properties, and the covering structure material with moisture and oxygen barrier properties. This composite structure achieves both protection against environmental factors and maintenance of quantum dot performance.

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 solution significantly improves the reliability of the quantum dot material by preventing moisture and oxygen from affecting its emitting efficiency, thereby maintaining high luminous performance over extended periods.

Implementation Method 1

The foregoing wavelength conversion material may absorb a first light emitted from the light-emitting diode then emits a second light with a different spectrum from that of the first light

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

the moisture and oxygen are blocked by the covering structure and the light-emitting element from the quantum dot material

Methodology Applied

Scientific EffectPhysical containment: Physical Containment

Data Source

PatentUS12317654B2Light-emitting device and manufacturing method thereof

Publication Date: 2025.05.27 EPISTAR CORP

AI summary

A light-emitting device comprises a light-emitting element, a covering structure, a quantum dot material block, and an adhesive structure is disclosed. The covering structure has a depressed part. The quantum dot material block is filled into the depressed part and enclosed by the light-emitting element and the covering structure. The light-emitting element, the covering structure, and the quantum dot material block are bonded together through the adhesive structure. Since the quantum dot material block is enclosed by the covering structure and the light-emitting element, the outer moisture and oxygen are blocked by the covering structure and the light-emitting element from the quantum dot material block, the decreasing emitting efficiency of the quantum dot material is further alleviated.