Flexible Display Panel Recessed Touch Electrode Design

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Solution Overview

Problem

Flexible touch display panels face issues with touch electrodes breaking or cracking due to bending, primarily because of the thin and narrow edges formed during the inkjet printing process of organic encapsulation layers, leading to mechanical weakness.

Innovation Solution

The display panel design incorporates a flexible substrate with an inorganic encapsulation layer and an inorganic insulation layer, featuring recessed structures that house touch electrodes and bridge structures, which are embedded within these layers to enhance mechanical strength and prevent breakage, while maintaining a thin and light profile.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the touch electrodes are made thin and narrow to maintain a slim display panel profile, then the device thickness is reduced, but the mechanical strength decreases making the electrodes prone to breakage during bending

Engineering Contradiction:

Improvedisplay panel thicknessVSAvoidtouch electrode mechanical strength

Core Design Contradiction:

Length of moving objectVSStrength

Solution Approach 1:

The touch electrodes and bridge structures are nested within recessed structures formed in the inorganic encapsulation layer and inorganic insulation layer. This nesting approach allows the electrodes to be protected by the surrounding encapsulation material, providing mechanical support and preventing breakage while maintaining the overall thin profile of the display panel.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The inorganic encapsulation layer and inorganic insulation layer are formed with different local properties: the recessed structures provide localized mechanical support to the touch electrodes where needed, while the rest of the layers maintain their protective and insulating functions. This local differentiation allows the electrodes to be thin overall while having reinforced sections at critical points.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If the touch electrodes are made thin and narrow to achieve a flexible and deformable display, then the flexibility is improved, but the reliability of the touch function deteriorates due to increased breakage risk

Engineering Contradiction:

Improvedisplay flexibilityVSAvoidtouch electrode reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The touch electrodes are nested within the recessed structures of the inorganic encapsulation layer, which acts as a protective shell. This nested configuration allows the display to be flexible and deformable while the encapsulation layer protects the electrodes from breaking during bending operations, thereby maintaining touch function reliability.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The inorganic encapsulation layer and inorganic insulation layer are formed beforehand to create recessed structures that will house the touch electrodes. This prior preparation provides mechanical cushioning and support to the electrodes before they are subjected to bending stresses, preventing breakage and ensuring reliable touch functionality.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Strength

If the touch electrodes are embedded in the inorganic encapsulation layer to prevent breakage, then the mechanical strength is improved, but the manufacturing complexity increases

Engineering Contradiction:

Improvetouch electrode mechanical strengthVSAvoidlayer structure complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The inorganic encapsulation layer and inorganic insulation layer are merged into a single integrated structure with recessed portions formed in both layers. This merging approach simplifies the manufacturing process by combining multiple functions (encapsulation, insulation, and electrode housing) into a unified layer structure, reducing the overall device complexity while maintaining electrode protection.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11011715B2Display panel and display device

Publication Date: 2021.05.18 WUHAN TIANMA MICRO ELECTRONICS CO LTD

AI summary

A display panel includes a thin film encapsulation layer which has a stack of layers: an organic encapsulation layer and an inorganic encapsulation layer covering the organic encapsulation layer; an inorganic insulation layer; also first touch electrodes; and first bridge structures. First and second recessed structures that are connected to each other are formed in the inorganic encapsulation layer and the inorganic insulation layer in one arrangement, or the first and second recessed structures are provided in the inorganic insulation layer in another arrangement. The first touch electrode and the first bridge structure are located in the first recessed structure and the second recessed structure, or the first bridge structure and the first touch electrode are located in the first recessed structure and the second recessed structure. The first touch electrode serves as a touch driving electrode or touch sensing electrode, and two first touch electrodes are electrically connected to each other through one first bridge structure.