Display Panel Insulating Layer for Flat Surface and Crack Prevention

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Solution Overview

Problem

Oxidation occurs between the organic light-emitting layer and electrodes in electroluminescent displays due to infiltration of oxygen and moisture, leading to issues like pores or cracks caused by thermal expansion coefficient differences between the planarization layer and the pixel driver, resulting in poor adhesion and potential separation during processing.

Innovation Solution

Incorporating an insulating layer between the pixel driver and planarization layer to prevent infiltration, with openings in the upper insulating layer allowing electrical connections, and using multiple conductive lines across stacked insulating layers to route signals while maintaining a flat surface, along with alignment markers and layered buffer materials for accurate component transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the pixel driver is disposed under and buried by the planarization layer, then the display panel can achieve a flat surface and proper structure, but pores or cracks are generated due to difference in thermal expansion coefficients and low adhesion between the planarization layer and the pixel driver

Engineering Contradiction:

Improveflat surfaceVSAvoidadhesion between planarization layer and pixel driver

Core Design Contradiction:

ShapeVSReliability

Solution Approach 1:

An adhesive layer is introduced as an intermediary between the planarization layer and the pixel driver. This adhesive layer specifically addresses the adhesion problem by providing strong bonding between the two components, preventing pore formation and crack generation while maintaining the flat surface structure achieved by burying the pixel driver under the planarization layer.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the pixel driver is disposed under and buried by the planarization layer, then the display panel can achieve proper structure, but oxidation occurs between the organic light-emitting layer and the electrodes due to infiltration of oxygen and moisture

Engineering Contradiction:

Improvestructure stabilityVSAvoidoxidation from oxygen and moisture infiltration

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

An organic protective layer is introduced as a thin film barrier between the pixel driver and the external environment. This protective layer specifically addresses the oxidation problem by preventing oxygen and moisture from infiltrating to the organic light-emitting layer and electrodes, while maintaining the structural stability achieved by the buried pixel driver configuration.

Inventive Principle:

Principle #30Flexible shells and thin films

3Ease of manufacture

If multiple layers of conductive lines are formed across stacked insulating layers, then signals and power can be routed while keeping the surface even, but the device complexity increases

Engineering Contradiction:

Improvesurface evennessVSAvoidnumber of conductive lines and insulating layers

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The conductive lines are distributed across multiple stacked insulating layers, utilizing the vertical dimension to route signals and power. This multi-layer approach maintains an even surface by hiding the complexity in the vertical dimension rather than creating surface irregularities, achieving proper signal routing while keeping the top surface flat and even.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 design enhances the reliability and manufacturing yield of organic light-emitting displays by preventing cracks and pores, ensuring stable performance and accurate alignment, allowing for adjustable brightness even if one light-emitting element fails.

Implementation Method 1

an insulating layer between the pixel driver and the planarization layer to prevent infiltration

Methodology Applied

Scientific EffectPhysical barrier (insulating layer):

Implementation Method 2

pores or cracks may be generated by a difference in thermal expansion coefficients of the planarization layer and the pixel driver during a subsequent process due to low adhesion

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS20250366292A1Display panel

Publication Date: 2025.11.27 LG DISPLAY CO LTD

AI summary

Disclosed herein is a display panel including a pixel driver in a display area and an insulating layer disposed under and covered by a planarization layer. The insulating layer includes an upper insulating layer having one or more openings that expose a plurality of pads of the pixel driver, allowing electrical connection to external lines. By positioning the insulating layer between the planarization layer and the pixel driver, the structure reduces the likelihood of pore formation caused by adhesion failure or thermal stress, thereby enhancing reliability and manufacturing yield.