Touch Sensor Module Bending Area Stress Distribution

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Solution Overview

Problem

Existing touch sensor modules face challenges in maintaining electrical and mechanical reliability, especially when subjected to bending or folding, which can lead to delamination and damage to sensing electrodes and traces in flexible display devices.

Innovation Solution

A touch sensor module design featuring a supporting structure with an adhesive material, a flexible circuit board, and an optical layer that covers the bending area, preventing delamination and damage by distributing stress and maintaining electrical connectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the touch sensor module is made flexible to enable bending, then adaptability is improved, but mechanical reliability deteriorates due to delamination and damage to sensing electrodes and traces

Engineering Contradiction:

ImproveflexibilityVSAvoidmechanical reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent employs flexible thin film structures for the touch sensor module, including flexible substrates and thin film electrodes that can withstand bending while maintaining structural integrity. The flexible circuit board uses thin film conductors and insulators that resist delamination during flexing, directly addressing the mechanical reliability issue while preserving flexibility.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent utilizes composite material structures combining multiple layers with different mechanical properties. The flexible substrate combines polymer materials with varying moduli to distribute bending stresses, while the adhesive layers use composite formulations that maintain strong bonding during flexing. This composite approach prevents delamination and protects sensing electrodes from damage while maintaining the module's flexibility.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If the touch sensor module is made flexible to enable bending, then adaptability is improved, but electrical reliability deteriorates due to damage to sensing electrodes and traces

Engineering Contradiction:

ImproveflexibilityVSAvoidelectrical reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent modifies material parameters such as the flexibility and conductivity of electrode materials to maintain electrical performance during bending. The sensing electrodes use materials with appropriate elastic modulus and electrical conductivity that remain stable under flexing conditions, preventing electrical failure while enabling the flexible form factor.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a supporting structure is added to protect the bending area, then mechanical reliability is improved, but device complexity increases

Engineering Contradiction:

Improvemechanical reliabilityVSAvoidstructural complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates the supporting structure with existing components of the touch sensor module. The flexible substrate itself serves as a supporting element, and additional support layers are combined with the adhesive and electrode structures rather than being separate additions. This merging approach provides mechanical protection during bending while minimizing increases in overall device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The supporting structure in the patent serves multiple functions: it provides mechanical strength during bending, acts as an adhesive substrate for mounting components, and serves as a protective layer for the sensing electrodes. This multi-functionality reduces the need for separate protective components, thereby limiting the increase in device complexity while improving mechanical reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

The solution enhances mechanical and electrical stability, preventing delamination and damage to the touch sensor module during bending, ensuring reliable operation even in flexible display devices with significant bending radii.

Implementation Method 1

the supporting layer includes an adhesive material

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS11714512B2Touch sensor module, window stack structure including the same and image display device including the same

Publication Date: 2023.08.01 DONGWOO FINE CHEM CO LTD

AI summary

A touch sensor module according to an embodiment of the present invention includes a touch sensor layer including a visual area, a bending area and a pad area, a flexible circuit board electrically connected to the touch sensor layer on the pad area of the touch sensor layer, supporting structure covering the touch sensor layer on the bending area, and an optical layer disposed on the visual area of the touch sensor layer. The optical layer partially covers the supporting structure on a portion of the bending area adjacent to the visual area.