Organic EL Device Cover Layer Protects Cathode During Buffer Formation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The existing methods for producing organic EL devices face issues with the damage to the cathode protective layer during the formation of the organic buffer layer, leading to potential cracks and deterioration of the counter electrode, resulting in non-light-emitting areas due to direct contact with printing apparatuses.

Innovation Solution

A method is introduced where a cover layer is formed between the cathode protective layer and the organic buffer layer, acting as a cushion to prevent damage from the printing apparatus, with a thickness range of 100 nm to 500 nm and made of organic low-molecular-weight materials, positioned outwardly from the display area to absorb stress and protect the cathode protective layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the organic buffer layer is made thinner to reduce overall device thickness and improve luminance, then luminance is improved, but the cathode protective layer is more likely to be damaged by contact with printing apparatus

Engineering Contradiction:

ImproveluminanceVSAvoidcathode protective layer integrity

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

A cover layer is introduced as an intermediary between the cathode protective layer and the organic buffer layer. This cover layer absorbs the impact from the printing apparatus during screen printing, preventing direct contact damage to the cathode protective layer while allowing the organic buffer layer to maintain its thin profile for improved luminance

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The cover layer is formed beforehand over the cathode protective layer to provide cushioning protection before the screen printing process occurs. This pre-positioned protective layer prevents cracks and damage to the cathode protective layer during subsequent manufacturing steps

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Manufacturing precision

If a screen printer is used to form the organic buffer layer, then the organic buffer layer can be formed with precise thickness control, but the printing apparatus may directly contact and damage the cathode protective layer

Engineering Contradiction:

Improveorganic buffer layer thickness controlVSAvoidmechanical damage to cathode protective layer

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The cover layer serves as a mediator that allows the screen printing apparatus to operate with precise thickness control while preventing the harmful mechanical contact from reaching the cathode protective layer. The cover layer absorbs the impact forces during the printing process

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9698389B2Method of producing organic EL device

Publication Date: 2017.07.04 LUMITEK DISPLAY TECH LTD

AI summary

A method of producing an organic EL device includes forming an organic EL element including a pixel electrode, a functional layer, and a counter electrode over a substrate, forming a cathode protective layer over the organic EL element, forming a cover layer over the cathode protective layer, forming an organic buffer layer over the cover layer, and forming a gas barrier layer over the organic buffer layer.