Light Emitting Device Moisture Barrier Thin Films

Solution Overview

Problem

Organic electro-luminescence display devices are prone to rapid deterioration due to moisture and oxygen exposure, leading to short lifetimes and increased volume when using metal caps for protection.

Innovation Solution

A light emitting device with a substrate, a light emitting member, and alternating layers of blocking and absorbing layers to prevent oxygen and moisture permeation, using materials like silicon oxide, magnesium oxide, and calcium oxide to form a dense protective barrier.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metal cap is used to cover the organic electro-luminescence display device, then moisture and oxygen contact is prevented, but the device volume and weight increase

Engineering Contradiction:

Improveprotection against moisture and oxygenVSAvoiddevice volume

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent replaces the metal cap with thin film blocking layers (such as aluminum oxide, silicon oxide) and absorbing layers that can be directly deposited on the organic light emitting layer. These thin films provide effective moisture and oxygen barrier protection while occupying minimal space, thus preventing device volume increase.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent employs a composite structure consisting of multiple alternating layers including blocking layers (made from materials like aluminum oxide, silicon oxide) and absorbing layers (made from materials like calcium oxide, barium oxide). This composite multi-layer structure provides superior protection against moisture and oxygen permeation compared to a single metal cap, while maintaining a compact form factor.

Inventive Principle:

Principle #40Composite materials

2Reliability

If a metal cap is used to cover the organic electro-luminescence display device, then moisture and oxygen contact is prevented, but the device weight increases

Engineering Contradiction:

Improveprotection against moisture and oxygenVSAvoiddevice weight

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent replaces the heavy metal cap with ultra-thin film layers that can be deposited directly on the organic light emitting layer. These thin films have negligible weight compared to metal caps, providing effective barrier protection without significant weight penalty.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent employs a composite structure consisting of multiple alternating layers including blocking layers (made from materials like aluminum oxide, silicon oxide) and absorbing layers (made from materials like calcium oxide, barium oxide). This composite multi-layer structure provides superior protection against moisture and oxygen permeation compared to a single metal cap, while maintaining a compact form factor.

Inventive Principle:

Principle #40Composite materials

3Device complexity

If the organic light emitting layer is exposed to air, then device structure is simple, but lifetime is rapidly reduced due to moisture and oxygen permeation

Engineering Contradiction:

Improvestructure complexityVSAvoiddevice lifetime

Core Design Contradiction:

Device complexityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the protective structure from a single thick metal cap to multiple thin film layers with different functional properties. The blocking layers provide barrier protection while the absorbing layers actively consume permeating moisture and oxygen, creating a multi-mechanism protection system that extends device lifetime.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure consisting of multiple alternating layers including blocking layers (made from materials like aluminum oxide, silicon oxide) and absorbing layers (made from materials like calcium oxide, barium oxide). This composite multi-layer structure provides superior protection against moisture and oxygen permeation compared to a single metal cap, while maintaining a compact form factor.

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

The solution significantly extends the lifetime of the light emitting device by preventing moisture and oxygen from reaching the organic light emitting layer, reducing volume and weight, and enhancing durability.

Implementation Method 1

The first blocking layer may include silicon oxide, silicon nitride, magnesium oxide, aluminum oxide, aluminum nitride, titanium oxide, polyacetylen group, polyimide group

Methodology Applied

Scientific EffectPermeation barrier:

Implementation Method 2

The absorbing layer is formed between the light emitting member and the first blocking layer to absorb a portion of the oxygen or the moisture that passes through the first blocking layer

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS7368869B2Light emitting device, display apparatus having the light emitting device, and method of manufacturing the display apparatus

Publication Date: 2008.05.06 SAMSUNG DISPLAY CO LTD

AI summary

A light emitting device includes a light emitting member formed on a substrate, a first blocking layer formed on the light emitting member and an absorbing layer interposed between the light emitting member or the first blocking layer. The first blocking layer prevents oxygen or moisture in air from permeating into the light emitting member generating light. The absorbing layer absorbs the oxygen or the moisture that passes through the first blocking layer. The light emitting device may have reduced volume and improved lifetime.