Conductive Planar Layer for Array Substrate Stress Management

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Solution Overview

Problem

The existing array substrates for organic electroluminescent display devices face issues with the peeling of organic resin planar layers due to stress mismatch with electrode materials, leading to low passing rates and long-term stability problems.

Innovation Solution

A conductive planar layer made of nanoscale metal material, such as silver, is applied and sintered to form a conductive planar layer that serves as both a reflective electrode and a pixel electrode, integrated with an inorganic buffer layer to reduce stress differences and improve stability, using ink-jet printing and sputtering methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If an organic resin planar layer is deposited on the switching element and then the ITO/Ag or AlNd/ITO electrode is deposited on the organic resin planar layer, then the switching element steps are covered and the electrode is formed, but the organic resin planar layer easily falls off due to stress mismatch between the organic resin material and the electrode material

Engineering Contradiction:
Improveease of manufactureVSAvoidreliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the material parameter of the planar layer from organic resin to inorganic material (such as silicon oxide or silicon nitride). This material substitution fundamentally alters the stress characteristics, making the planar layer's stress compatible with the electrode materials. The inorganic planar layer is formed using standard semiconductor deposition techniques, and its stress can be controlled during the deposition process to match the electrode stress, thereby preventing peeling while maintaining ease of manufacture through established fabrication processes.

Inventive Principle:
Principle #35Parameter changes

2Shape

If an organic resin planar layer is used to cover the switching element steps, then the surface is planarized, but the stress mismatch between organic resin and electrode materials causes peeling and reduces long-term stability

Engineering Contradiction:
ImproveshapeVSAvoidstability of the object's composition
Core Design Contradiction:
ShapeVSStability of the object's composition

Solution Approach 1:

The patent changes the material composition parameter from organic resin to inorganic material for the planar layer. This substitution maintains the planarization function (shape control) while fundamentally improving compositional stability. The inorganic planar layer exhibits better chemical stability, thermal stability, and stress compatibility with electrode materials, eliminating the peeling issue and enhancing long-term device stability without compromising the planar surface morphology.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a conductive planar layer made of nanoscale metal material is applied and sintered, then both reflective electrode and pixel electrode functions are integrated, but additional sintering process is required

Engineering Contradiction:
Improvedevice complexityVSAvoidproductivity
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent merges the functions of the reflective electrode and pixel electrode into a single integrated conductive planar layer. This inorganic planar layer is formed using standard sputtering or deposition processes that are already part of the manufacturing sequence, eliminating the need for separate reflective electrode and pixel electrode deposition steps. The integration reduces device structural complexity and streamlines the production process, improving productivity despite the initial perception of added complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 solution enhances the long-term stability and manufacturing yield by eliminating peeling issues and simplifying the production process, as both the planar layer and pixel electrode are composed of inorganic materials, reducing material stress and improving reliability.

Implementation Method 1

a conductive planar layer made of nanoscale metal material, such as silver, is applied and sintered to form a conductive planar layer

Methodology Applied
Scientific EffectSintering: Sintering

Implementation Method 2

using ink-jet printing and sputtering methods

Methodology Applied
Scientific EffectInk-jet printing:

Implementation Method 3

using ink-jet printing and sputtering methods

Methodology Applied
Scientific EffectSputtering: Sputtering

Data Source

PatentEP3333891B1Array substrate having conductive planarization layer and preparation method therefor
Publication Date: 2022.08.31 BOE TECHNOLOGY GROUP CO LTD
  • EP3333891B1 patent drawingFigure 1~2
  • EP3333891B1 patent drawingFigure 3~7
  • EP3333891B1 patent drawingFigure 8~10

AI summary

An array substrate includes a substrate (100) having a plurality of sub-pixel regions. Each sub-pixel region includes: a switching element (1) disposed on the substrate, a conductive planar layer (113) disposed on the switching element (1), and a pixel electrode (111) disposed on the conductive planar layer (113), the pixel electrode (111) being electrically connected to the output electrode (105) of the switching element (1). Such array substrate improves the instability of the device caused by stress between materials, enhances the long-term stability of the device, and simplifies the manufacturing process.