Organic EL Intermediate Layer for Resistance and Protection

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Solution Overview

Problem

The formation of a layer including fluoride of an alkali metal or an alkaline-earth metal across all pixels in organic EL display panels increases electrical resistance between wirings and the cathode, making it difficult to prevent voltage variation and moisture/oxygen intrusion.

Innovation Solution

Incorporating an intermediate layer with fluoride of an alkali or alkaline-earth metal and a second metal that cleaves the bond between the first metal and fluorine, reducing the high electrical resistivity and preventing moisture and oxygen intrusion into the cathode and organic functional layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a layer including fluoride of an alkali metal or an alkaline-earth metal is formed for the entire pixels, then moisture and oxygen intrusion into the cathode and organic functional layers is prevented, but electrical resistance between wirings and the cathode increases

Engineering Contradiction:

Improveprotection against moisture and oxygen intrusionVSAvoidelectrical resistance between wirings and cathode

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by forming the fluoride-containing intermediate layer selectively only in regions where moisture and oxygen protection is needed (above the cathode and organic functional layers), while leaving regions above the wirings free of fluoride to maintain low electrical resistance. This spatial differentiation allows the same layer to provide protection in some areas without harming conductivity in others.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The intermediate layer is segmented into different regions with different compositions: a first region above the cathode containing fluoride for protection, and a second region above the wirings without fluoride to maintain conductivity. This segmentation resolves the contradiction by allowing the protective function and conductive function to be fulfilled in different spatial zones.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If voltage is applied to the cathode from a peripheral part, then the cathode can be formed for entire pixels, but voltage drop occurs due to increase of electrical resistance of the cathode itself

Engineering Contradiction:

Improvecathode formation for entire pixelsVSAvoidvoltage uniformity across pixels

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces an intermediate layer with electron injection properties between the cathode and light-emitting layers as a preliminary measure to facilitate electron injection. This preliminary action compensates for voltage drops by improving the cathode's ability to supply electrons, thereby maintaining voltage uniformity across the entire pixel area despite the peripheral voltage application configuration.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If wet process is used to form organic functional layers, then manufacturing is simplified, but moisture and oxygen intrude into the cathode and organic functional layers

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidprotection against moisture and oxygen intrusion

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces an intermediate layer as a mediator between the wet-process-formed organic functional layers and the cathode. This intermediate layer serves as a protective barrier that prevents moisture and oxygen from the wet process from intruding into the sensitive cathode and organic functional layers, thereby enabling the use of simplified wet manufacturing processes without compromising device reliability.

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

This configuration reduces electrical resistance between wirings and the cathode, preventing voltage variation and enhancing the durability of the organic EL display panel by minimizing the impact of moisture and oxygen.

Implementation Method 1

a second metal that has a property of cleaving a bond between the first metal and fluorine in the fluoride

Methodology Applied

Scientific EffectBond cleavage: Chemical Bonding

Implementation Method 2

an intermediate layer that is disposed above the light-emitting layer and the wiring... prevents intrusion of moisture and oxygen into the cathode and organic functional layers

Methodology Applied

Scientific EffectPhysical barrier: Physical Containment

Data Source

PatentUS9559327B2Organic light emitting device and method for manufacturing same

Publication Date: 2017.01.31 MAGNOLIA BLUE CORP

AI summary

An organic light-emitting device includes: an anode; a wiring that is disposed side-by-side with and spaced from the anode; a light-emitting layer that is disposed above the anode, and includes an organic light-emitting material; an intermediate layer that is disposed above the light-emitting layer and the wiring; an organic functional layer that is disposed above the intermediate layer, and has an electron injection property or an electron transport property; a cathode that is disposed above the organic functional layer. The intermediate layer includes: a fluoride of a first metal, the first metal being an alkali metal or an alkaline-earth metal; and a second metal that has a property of cleaving a bond between the first metal and fluorine in the fluoride.