Blocking Layer Shields EL Emission Portion from UV Curing Damage

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Solution Overview

Problem

Conventional methods for sealing organic electroluminescent (EL) displays are inadequate in preventing damage to the emission portion from moisture and external energy during manufacturing, as UV-curing sealants can permeate and harm the organic emission layer, and thin LiF layers fail to provide effective protection.

Innovation Solution

A blocking layer is interposed between the second electrode layer and the seal member in the EL display device, formed from materials like Li, Ca, LiF, CaF2, or MgF2, to a thickness of about 10 Å to 50 Å, which prevents damage from UV rays and heat during the curing process of the seal layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If UV-curing sealant is applied to seal the emission substrate, then moisture protection is improved, but the organic emission portion is damaged by UV ray permeation

Engineering Contradiction:

Improvemoisture protectionVSAvoidUV ray damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A blocking layer is introduced as an intermediary component between the seal member and the organic emission portion. This blocking layer specifically blocks UV rays from the UV-curing sealant from permeating through to damage the organic emission layer, while still allowing the sealant to effectively seal against moisture. The blocking layer acts as a mediator that prevents the harmful interaction between UV radiation and the organic emission material.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sealing structure employs a composite material approach by combining the UV-curing sealant with a UV-blocking layer. This composite structure leverages the moisture-blocking properties of the sealant while the blocking layer component provides UV radiation protection. The combination of these two materials creates a sealing system that addresses both moisture protection and UV damage prevention simultaneously.

Inventive Principle:

Principle #40Composite materials

2Illumination intensity

If LiF layer is used to improve color efficiency, then color performance is improved, but the layer is too thin to protect from external energy

Engineering Contradiction:

Improvecolor efficiencyVSAvoidexternal energy damage

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The protective function is segmented into two distinct layers: a thin LiF layer that maintains color efficiency and an additional blocking layer that provides UV protection. By dividing the protection function into separate layers, the LiF layer can be kept thin for optimal color performance while the blocking layer provides the necessary thickness for UV ray blocking without compromising the color efficiency function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The blocking layer serves as an intermediary protective layer between the external environment (UV rays) and the LiF/organic emission structure. This intermediary layer allows the LiF layer to maintain its color efficiency function while the blocking layer absorbs or reflects UV radiation, preventing it from reaching and damaging the organic emission portion.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If seal member is applied directly to the emission portion, then sealing is simplified, but the emission portion is exposed to external energy damage

Engineering Contradiction:

Improvesealing structureVSAvoidexternal energy exposure

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #24Intermediary (Mediator)

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 blocking layer effectively seals the emission portion against moisture and external energy, increasing the lifespan of the EL display while maintaining the color coordinate of emitted light by preventing damage during manufacturing.

Implementation Method 1

A blocking layer interposed between at least a portion of the seal member and the second electrode layer may overlap at least the display region

Methodology Applied

Scientific EffectUV ray blocking: Absorption (EM radiation)

Implementation Method 2

prevents damage from UV rays and heat during the curing process of the seal layers

Methodology Applied

Scientific EffectHeat blocking: Absorption (EM radiation)

Implementation Method 3

A seal member may seal at least the display region

Methodology Applied

Scientific EffectPhysical containment: Physical Containment

Data Source

PatentUS8004184B2Electro-luminescent display device

Publication Date: 2011.08.23 SAMSUNG DISPLAY CO LTD

AI summary

The present invention provides an electro-luminescent (EL) display device and a method of fabricating the same. The EL display device includes a substrate including a display region. The display origin may include a first electrode layer, a second electrode layer, and an emission portion interposed therebetween. A seal member may seal at least the display region. A blocking layer interposed between the seal member and the second electrode layer may overlap the display region.