Inorganic Sealing Layer with Uneven Surface for OLED Moisture Resistance

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Solution Overview

Problem

Conventional inorganic sealing members in organic electroluminescent display devices are prone to cracking under external stress, leading to reduced moisture resistance and potential damage to the pixels.

Innovation Solution

An inorganic sealing member with a spring-like shape and an upper organic layer is used, where the inorganic layer has an uneven surface and protrusions to distribute stress, and the organic layer absorbs additional stress, preventing cracks and maintaining moisture resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an inorganic sealing member is used to improve moisture resistance, then moisture resistance is improved, but the sealing member becomes more easily broken by external stress

Engineering Contradiction:

Improvemoisture resistanceVSAvoidresistance to external stress

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The sealing member is constructed as a composite structure combining an inorganic layer and an organic layer. The inorganic layer provides moisture resistance while the organic layer provides flexibility and stress resistance. This composite approach allows the sealing member to simultaneously achieve both moisture resistance and resistance to external stress, resolving the technical contradiction between these two properties.

Inventive Principle:

Principle #40Composite materials

2Reliability

If an inorganic sealing member is used to improve moisture resistance, then moisture resistance is improved, but product life is reduced due to cracking

Engineering Contradiction:

Improvemoisture resistanceVSAvoidproduct life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The composite structure of inorganic and organic layers prevents cracking that would otherwise occur in pure inorganic sealing members. The organic layer acts as a stress-absorbing buffer that prevents crack propagation, thereby extending product life while maintaining the moisture resistance provided by the inorganic layer.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The organic layer is positioned between the inorganic sealing layer and external stress sources to provide beforehand cushioning. This layer absorbs and distributes external stresses before they can reach the inorganic layer, preventing stress concentration and crack formation that would reduce product life.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Ease of manufacture

If a flat inorganic sealing layer is used, then manufacturing is simple, but stress concentrates at specific points causing cracks

Engineering Contradiction:

Improvesealing layer fabricationVSAvoidcrack resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The inorganic layer is designed with an uneven surface profile featuring protrusions and recesses rather than a flat surface. This dimensional change creates a more complex geometry that distributes stress more evenly across the layer, preventing stress concentration at specific points while still maintaining ease of manufacture through established coating techniques.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The surface morphology parameter of the inorganic layer is changed from flat to uneven with specific protrusion heights and spacing. This parameter change transforms the stress distribution characteristics, allowing the layer to resist cracking while remaining manufacturable using standard deposition processes.

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 effectively reduces the occurrence of cracks in the inorganic layer, enhancing the sealing member's moisture resistance and extending the lifespan of the organic electroluminescent display device to 10,000 hours or more by distributing stress and absorbing external forces.

Implementation Method 1

the inorganic layer has an uneven shape... Each of the upper surface and the lower surface of the inorganic layer has an uneven shape

Methodology Applied

Scientific EffectStress distribution:

Implementation Method 2

the organic layer absorbs additional stress, preventing cracks

Methodology Applied

Scientific EffectStress absorption:

Implementation Method 3

the sealing member blocks moisture and gas which may be introduced from outside the device to the pixels

Methodology Applied

Scientific EffectMoisture and gas barrier:

Data Source

PatentUS9277602B2Organic electroluminescent display device

Publication Date: 2016.03.01 SAMSUNG DISPLAY CO LTD

AI summary

An organic electroluminescent display device includes a substrate, pixels on the substrate and each including an organic emission layer, and a sealing member covering the pixels and configured to block moisture and gas from outside the organic electroluminescent display device to the pixels. The sealing member includes an inorganic layer of which a lower surface is opposite to an upper surface thereof and closer to the pixels than the upper surface, and each of the upper surface and the lower surface has an uneven shape.