Electron Injection Layer Layout for Moisture-Resistant OLED Displays

Solution Overview

Problem

Self-light emitting display devices, particularly those with organic light emitting devices, are prone to reliability and lifespan issues due to moisture penetration, which can cause pixel shrinkage and reduce the effectiveness of the display.

Innovation Solution

A light emitting display device configuration that includes a substrate with an active and non-active area, where a bank structure exposes emission parts through first holes in the active area and a power voltage line through a second hole in the non-active area, utilizing an electron injection layer made of inorganic materials to prevent moisture penetration by extending into the second hole and connecting the cathode to the power voltage line, thereby protecting the internal layers from moisture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the bank structure is modified to expose the power voltage line through a second hole in the non-active area, then the cathode can be connected to the power voltage line effectively, but moisture penetration risk increases due to the additional opening in the bank structure

Engineering Contradiction:

Improveconnection reliabilityVSAvoidmoisture penetration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The electron injection layer serves as an intermediary component that performs dual functions: it provides electrical connection between the cathode and power voltage line, and simultaneously acts as a moisture barrier by extending into the second hole to seal the opening. This mediator approach resolves the contradiction by introducing a component that fulfills both connection and protection requirements.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The electron injection layer is designed to perform multiple functions simultaneously: electron injection for device operation, electrical connection between layers, and moisture barrier protection by sealing the second hole. This multi-functionality allows the same component to address both the connection reliability requirement and the moisture penetration prevention requirement.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If the electron injection layer extends into the second hole to prevent moisture penetration, then reliability improves, but device complexity increases due to extended layer configuration

Engineering Contradiction:

Improvemoisture protectionVSAvoidlayer extension complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The electron injection layer is designed to perform multiple functions simultaneously: electron injection for device operation, electrical connection between layers, and moisture barrier protection by sealing the second hole. This multi-functionality allows the same component to address both the connection reliability requirement and the moisture penetration prevention requirement.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Illumination intensity

If the organic light emitting devices are used to achieve compactness and clear color display, then display performance improves, but inner organic layers become vulnerable to moisture, reducing lifespan

Engineering Contradiction:

Improvedisplay qualityVSAvoidlifespan

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The encapsulation structure and electron injection layer are designed beforehand to prevent moisture from reaching the vulnerable organic layers. The electron injection layer extends into the second hole to seal openings, and the encapsulation structure provides additional protective barriers, creating a preemptive defense system against moisture penetration before it can damage the organic light emitting layers.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The electron injection layer serves as an intermediary component that performs dual functions: it provides electrical connection between the cathode and power voltage line, and simultaneously acts as a moisture barrier by extending into the second hole to seal the opening. This mediator approach resolves the contradiction by introducing a component that fulfills both connection and protection requirements.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11839127B2Light emitting display device with electron injection layer at non-active area

Publication Date: 2023.12.05 LG DISPLAY CO LTD

AI summary

Disclosed is a light emitting display device which prevents pixel shrinkage and improves reliability by changing the structure of a bank and the inner structures of light emitting devices outside an active area of the light emitting display device.