Organic EL Display Moisture Blocking Layer Etching Protection

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Solution Overview

Problem

In organic electroluminescence (EL) display devices, the removal of the sealing layer in the peripheral circuit region can lead to breakage of the moisture blocking region, causing moisture infiltration and potential corrosion of wiring due to uneven spreading of the mask material during dry etching.

Innovation Solution

A thin film transistor substrate with a moisture blocking layer of different composition than the sealing layer, where the moisture blocking layer is formed of SiO or SiON and has a slower etching speed than the sealing layer, which is composed of SiN, to prevent breakage and corrosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the sealing layer is removed in the peripheral circuit region by dry etching, then the sealing layer can be selectively removed, but the mask material does not evenly spread in the moisture blocking region causing breakage of the moisture blocking region

Engineering Contradiction:

Improveselective removal of sealing layerVSAvoideven spreading of mask material

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent divides the protective layering structure into functionally distinct segments: a sealing layer for overall protection and a moisture blocking layer specifically for preventing moisture infiltration in the moisture blocking region. This segmentation allows the mask to be applied selectively and prevents the mask material from directly contacting and damaging the moisture blocking layer, as the sealing layer acts as a buffer between the mask and the moisture blocking layer during the etching process.

Inventive Principle:

Principle #1Segmentation

2Productivity

If the mask material is applied to remove the sealing layer, then the sealing layer can be etched away, but the moisture blocking layer may be broken due to uneven mask spreading

Engineering Contradiction:

Improveetching efficiencyVSAvoidintegrity of moisture blocking region

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The moisture blocking layer is formed on the passivation layer before the sealing layer is applied and before the mask removal process. This preliminary action ensures that the moisture blocking layer is already in place and protected by the sealing layer during subsequent manufacturing steps, preventing breakage before it can occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The sealing layer serves as an intermediary protective barrier between the mask material and the moisture blocking layer. During the mask removal process, the sealing layer absorbs the mechanical stress and prevents direct contact between the mask material and the moisture blocking layer, thereby preventing breakage while allowing the etching process to proceed efficiently.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If the moisture blocking region is broken, then mask material can infiltrate, but this causes corrosion of wiring and device failure

Engineering Contradiction:

Improvelayer structureVSAvoidmoisture and mask material infiltration

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a cushioning protective mechanism by forming the moisture blocking layer on the passivation layer before applying the sealing layer. This preliminary protective layer acts as a cushion that prevents harmful infiltration if the sealing layer is damaged or if mask material penetrates during the removal process, thereby preventing corrosion of underlying wiring and device failure.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent employs a composite layering structure consisting of multiple materials with different functions: the passivation layer, the moisture blocking layer (with different composition from the sealing layer), and the sealing layer. This composite structure provides multiple barriers against moisture and mask material infiltration, ensuring that even if one layer is compromised, the underlying wiring remains protected.

Inventive Principle:

Principle #40Composite materials

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

Prevents breakage of the moisture blocking region and subsequent corrosion of wiring by ensuring the moisture blocking layer is not etched during the removal of the sealing layer, effectively maintaining the integrity of the display device.

Implementation Method 1

an etching speed as to the moisture blocking layer is smaller than an etching speed as to the sealing layer

Methodology Applied

Scientific EffectEtching speed difference:

Data Source

PatentUS10340478B2Organic EL display device and method of manufacturing an organic EL display device

Publication Date: 2019.07.02 MAGNOLIA WHITE CORP

AI summary

An organic EL display device includes a thin film transistor substrate that has a circuit layer, a passivation layer, a lower electrode formed in each pixel in a display region, an organic material layer that is in contact with the lower electrode, an upper electrode that covers the organic material layer, and a sealing layer that entirely covers the base material. The thin film transistor substrate has the display region, and a moisture blocking region that surrounds the display region. On the moisture blocking region, the circuit layer, the passivation layer, the moisture blocking layer, and the sealing layer are laminated in this order. A composition of the moisture blocking layer is different from a composition of the sealing layer.