Display Pad Passivation Structure Against Delamination and Dark Spots

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Solution Overview

Problem

Flexible display devices face issues with interface delamination and dark spot defects in the pad area due to peeling and exposure of pads during manufacturing, leading to impaired image quality and reduced lifespan.

Innovation Solution

A passivation layer made of inorganic material is disposed to cover the ends of pad patterns in the pad area, minimizing interface delamination and protecting pads from residues during manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a planarization layer is disposed in the pad area, then surface flatness is improved, but interface delamination occurs between layers

Engineering Contradiction:

Improvesurface flatnessVSAvoidinterface adhesion

Core Design Contradiction:

ShapeVSReliability

Solution Approach 1:

The patent applies different material properties to different regions: an inorganic passivation layer is specifically disposed in the pad area to cover pad patterns, while the planarization layer covers the active area. This local differentiation prevents interface delamination in the pad area while maintaining surface flatness in the active area.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The inorganic passivation layer acts as an intermediary between the pad patterns and the planarization layer. It provides a stable interface that prevents delamination, allowing the planarization layer to be disposed over the pad area without causing interface adhesion problems.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Volume of moving object

If pads are located close to the active area to reduce device size, then device volume is reduced, but pads are exposed to contaminants during manufacturing

Engineering Contradiction:

Improvedevice sizeVSAvoidcontamination

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The inorganic passivation layer is disposed to cover the pad patterns before subsequent manufacturing processes. This preliminary protective action prevents contaminants from reaching the pads during manufacturing, even when pads are located close to the active area.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The inorganic passivation layer creates a protected environment around the pad patterns, isolating them from harmful chemicals and contaminants during the manufacturing process, similar to how an inert atmosphere protects sensitive materials.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Ease of manufacture

If an organic planarization layer is used to cover pads, then ease of manufacture is improved, but residue accumulation occurs causing dark spot defects

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidpad pattern cleanliness

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the material parameter of the protective layer from organic to inorganic. The inorganic passivation layer does not generate residue during manufacturing processes, eliminating dark spot defects while still providing the necessary coverage and protection for pad patterns.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12604612B2Display device including pad structure for enhanced reliability

Publication Date: 2026.04.14 LG DISPLAY CO LTD

AI summary

A display device can include a substrate including an active area in which a plurality of pixels are disposed, and a non-active area extending from the active area and including a pad area; a plurality of pads disposed in the pad area; a plurality of link lines disposed in the non-active area and connected to the plurality of pads; and a driver integrated circuit (IC) bonded to the plurality of pads. The display device can further include a passivation layer disposed on portions of the plurality of pads disposed in the pad area, in which outer edges of each of the plurality of pads are covered by the passivation layer.