Transparent Moisture Absorption Layer for OLED Encapsulation

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Solution Overview

Problem

Conventional organic electroluminescent devices are prone to deterioration due to moisture permeation and struggle with opacity, making them unsuitable for front emission type devices with low moisture absorption ability.

Innovation Solution

A transparent moisture absorption layer comprising nano-sized metal oxides or salts with an average particle diameter of 100 nm or less, a binder, and a dispersant is integrated between substrates in the organic electroluminescent device, providing excellent moisture absorption and transparency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional desiccant powder or film is used for moisture absorption, then moisture absorption ability is improved, but transparency is deteriorated making front emission type device fabrication difficult

Engineering Contradiction:

Improvemoisture absorption abilityVSAvoidtransparency

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The patent changes the particle size parameter of the desiccant from conventional micrometer scale (0.1-200 μm) to nanometer scale (1-100 nm). This parameter change allows the desiccant particles to become transparent while maintaining moisture absorption ability, resolving the contradiction between moisture absorption performance and transparency for front emission type devices.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material by combining ultra-fine nanoparticulate desiccant (1-100 nm) with a binder to form a transparent moisture absorption layer. This composite structure maintains the moisture absorption functionality while achieving the required transparency for front emission type organic electroluminescent devices.

Inventive Principle:

Principle #40Composite materials

2Reliability

If airtight container with drying means is used, then moisture protection is improved, but device thickness is increased

Engineering Contradiction:

Improvemoisture protectionVSAvoiddevice thickness

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The patent merges the moisture absorption function directly into the encapsulation structure by forming a transparent moisture absorption layer on the encapsulation substrate. This integration eliminates the need for separate airtight containers with bulky drying means, thereby maintaining moisture protection while reducing overall device thickness.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent uses a thin transparent moisture absorption layer (formed from nanoparticulate desiccant mixed with binder) as part of the encapsulation structure. This thin film approach provides effective moisture protection without the bulk of conventional airtight containers, enabling thinner overall device design.

Inventive Principle:

Principle #30Flexible shells and thin films

3Quantity of substance

If desiccant powder with particle size 0.1-200 μm is used, then moisture absorption capacity is improved, but transparency is lost making the device opaque or translucent

Engineering Contradiction:

Improvemoisture absorption capacityVSAvoidtransparency

Core Design Contradiction:

Quantity of substanceVSIllumination intensity

Solution Approach 1:

The patent dramatically reduces the particle size parameter from 0.1-200 μm to 1-100 nm (1000 times smaller in linear dimension). This ultra-fine nanoparticulate size allows light to pass through without significant scattering, maintaining transparency while the high surface area to volume ratio of nanoparticles preserves moisture absorption capacity.

Inventive Principle:

Principle #35Parameter changes

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 enables the creation of a long-lasting, transparent moisture absorption layer that maintains high transmittance and moisture absorption, suitable for front emission type devices, overcoming the limitations of conventional getter materials.

Implementation Method 1

a transparent moisture absorption layer which comprises at least one of a metal oxide and a metal salt having an average particle diameter of about 100 nm or less

Methodology Applied

Scientific EffectMoisture absorption: Absorption (physical)

Data Source

PatentUS8044584B2Organic electroluminescent device and method for manufacturing the same

Publication Date: 2011.10.25 SAMSUNG DISPLAY CO LTD

AI summary

An organic electroluminescent device includes a substrate, an encapsulation substrate, an organic electroluminescent portion interposed between the substrate and the encapsulation substrate and a transparent moisture absorption layer. The transparent moisture absorption layer comprises at least one of a metal oxide and a metal salt with an average particle diameter of about 100 nm or less, a binder, and a dispersant. The transparent moisture absorption layer may be disposed in an internal space provided by the substrate and the encapsulation substrate and may be used in a front emission type organic electroluminescent device.