Organic EL Desiccant Layer Uniform Moisture Diffusion

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Solution Overview

Problem

In organic EL display devices, moisture can penetrate and cause local absorption by the desiccant layer, leading to reduced moisture absorption reliability and potential cracking, which affects light emission characteristics and display quality.

Innovation Solution

A structure with a desiccant layer surrounded by a moisture high-permeable layer and a sealing member, where the moisture high-permeable layer has a frame shape and is positioned between the substrate and the opposite substrate, ensuring moisture is diffused and absorbed uniformly by the desiccant layer, preventing local absorption and allowing for increased desiccant layer thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a desiccant layer is used to absorb moisture in organic EL display devices, then moisture absorption ability is improved, but local moisture absorption occurs at the outer periphery leading to saturation and cracking

Engineering Contradiction:

Improvemoisture absorption reliabilityVSAvoiddesiccant layer uniformity

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

A moisture high-permeable layer is introduced as an intermediary between the sealing member and the desiccant layer. This layer mediates moisture transport by allowing moisture to diffuse uniformly across its entire area before reaching the desiccant layer, preventing direct localized moisture contact at the outer periphery and ensuring homogeneous moisture distribution to the desiccant layer.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The moisture high-permeable layer is designed with spatially varying properties - it has high moisture permeability throughout its structure to enable uniform moisture diffusion. This creates a localized quality distribution where moisture flux is homogenized across different regions before reaching the desiccant layer, preventing peripheral saturation while maintaining overall absorption capacity.

Inventive Principle:

Principle #3Local quality

2Reliability

If the desiccant layer thickness is increased to improve moisture absorption capacity, then moisture absorption ability is improved, but cracking occurs at the outer periphery due to localized cure shrinkage

Engineering Contradiction:

Improvemoisture absorption capacityVSAvoiddesiccant layer integrity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The moisture high-permeable layer acts as a buffer that decouples the desiccant layer thickness from moisture concentration gradients. By uniformly distributing moisture flux across the entire desiccant layer surface, it eliminates localized shrinkage stresses that would otherwise cause cracking in thicker desiccant layers, particularly at the outer periphery.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Speed

If moisture is absorbed directly by the desiccant layer without diffusion, then moisture absorption speed is improved, but local saturation occurs at the outer periphery reducing overall effectiveness

Engineering Contradiction:

Improvemoisture absorption speedVSAvoidmoisture absorption uniformity

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The moisture high-permeable layer performs preliminary moisture diffusion and homogenization before moisture reaches the desiccant layer. This preliminary action ensures that moisture is uniformly distributed across the entire desiccant layer surface, preventing localized saturation and enabling the entire desiccant layer to participate in moisture absorption, thereby maintaining high overall absorption capacity.

Inventive Principle:

Principle #10Preliminary action

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 reliably absorbs moisture, preventing local absorption and ensuring consistent moisture absorption by the desiccant layer, thereby maintaining light emission characteristics and display quality while allowing for a thicker desiccant layer without local saturation or cracking.

Implementation Method 1

moisture having penetrated through a sealing member (sealing resin) is absorbed by the desiccant layer. However, because the moisture is absorbed into the interior of the desiccant layer without being sufficiently diffused

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

a desiccant (getter) is filled inside the sealing resin to provide a desiccant layer

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS9692011B2Electroluminescent apparatus

Publication Date: 2017.06.27 SHARP KK

AI summary

In an organic EL display device (electroluminescence device) including an organic EL element (electroluminescence element), the organic EL element is covered with a desiccant layer. Between a TFT substrate (substrate) and an opposite substrate, a frame-shaped moisture high-permeable layer and a frame-shaped sealing member are disposed in a state successively surrounding the desiccant layer.