Touch Sensor Protrusions for Flexible Display Adhesion

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Solution Overview

Problem

Conventional touch sensors face challenges in flexibility and adhesion when integrated into flexible display devices, particularly when these devices are folded, bent, or rolled, leading to potential separation from the polarizer or display panel.

Innovation Solution

The touch sensor employs a flexible substrate with transparent conductive materials and minute protrusions on the touch electrodes, resembling the cilia shape of a Gecko lizard's foot, to provide strong adherence without separate adhesives, ensuring the sensor remains attached during device manipulation and reducing thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a flexible substrate is used to improve flexibility and portability, then the device can be folded or bent, but the touch sensor may separate from the polarizer or display panel during manipulation

Engineering Contradiction:
ImproveflexibilityVSAvoidadhesion
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The invention introduces minute protrusions (nanoscale dimension) on the touch electrode surface to create adhesion points. These protrusions extend in the vertical dimension (Z-axis) from the electrode surface, providing mechanical interlocking with the polarizer or display panel during folding or bending operations, thus preventing separation while maintaining flexibility.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The touch electrodes are designed with non-uniform surface morphology, featuring minute protrusions concentrated at specific locations where adhesion is critical. This local modification of surface quality enhances adhesion strength at key interface points without compromising the overall flexibility of the touch sensor structure.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If conventional touch sensors are integrated into flexible display devices, then the device can be manufactured, but the sensors lack flexibility and may defect after transformation

Engineering Contradiction:
ImprovemanufacturabilityVSAvoidflexibility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The touch sensor employs a flexible substrate structure with thin-film electrodes that can be transformed (folded, bent, or rolled). The minute protrusions on the electrode surface provide adhesion without requiring separate adhesive layers, maintaining flexibility while enabling integration into transformable display devices.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If separate adhesives are used to improve adhesion, then the touch sensor can be firmly attached, but the thickness and manufacturing complexity increase

Engineering Contradiction:
ImproveadhesionVSAvoidstructure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the adhesion function with the touch electrode structure itself by forming minute protrusions directly on the electrode surface. This integration eliminates the need for separate adhesive layers, reducing structural complexity and thickness while maintaining reliable adhesion between the touch sensor and polarizer or display panel.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If separate adhesives are used to ensure attachment, then the sensor remains attached during manipulation, but the overall thickness increases

Engineering Contradiction:
ImproveadhesionVSAvoidthickness
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The adhesion function is integrated into the touch electrode structure through minute protrusions, eliminating separate adhesive layers. This merging reduces the overall thickness of the touch sensor assembly while ensuring reliable attachment during folding or bending operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Instead of adding thickness in the vertical dimension through adhesive layers, the invention creates adhesion through nanoscale protrusions that extend vertically from the electrode surface. This approach provides strong adhesion with minimal thickness increase, as the protrusions create mechanical interlocking without requiring thick adhesive material.

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 solution enhances the flexibility and adhesion of the touch sensor, preventing separation from the display panel or polarizer, even during folding or rolling, while reducing the overall thickness and manufacturing complexity, thus improving optical characteristics and user interaction.

Implementation Method 1

the plurality of first and second minute protrusions combine at least one of a polarizer positioned on the touch sensor and the display panel by van der Waals forces

Methodology Applied
Scientific Effectvan der Waals force: Van der Waals Force

Data Source

PatentEP3062202B1Touch sensor, manufacturing method thereof, and display device including the same
Publication Date: 2021.05.12 SAMSUNG DISPLAY CO LTD
  • EP3062202B1 patent drawingFigure 1
  • EP3062202B1 patent drawingFigure 2~3
  • EP3062202B1 patent drawingFigure 4~5

AI summary

A touch sensor (400) includes a touch substrate (404), a plurality of first touch electrodes (410) extending in a first direction, a plurality of second touch electrodes (420) extending in a second direction crossing the first direction, and a plurality of protrusions (413, 423) on at least one of the plurality of first and second touch electrodes.