Touch Sensing Device Fast Axis Alignment via Segmented Film Bonding

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Solution Overview

Problem

Conventional methods for manufacturing touch sensing devices with optical film laminates face challenges in aligning the fast axes of substrates, leading to misalignment and difficulties in mass production.

Innovation Solution

A method involving biaxially stretched material films where segments are cut and bonded to maintain their original orientations, reducing misalignment and eliminating the need to measure fast axis orientations, enabling efficient mass production of touch sensing devices with aligned substrates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If two substrates are obtained by dividing a biaxially-stretched PET film into multiple parts in the widthwise direction, then material films can be efficiently produced, but the fast axes of the substrates extend in significantly different directions making alignment difficult

Engineering Contradiction:
Improvematerial film production efficiencyVSAvoidfast axis alignment precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention segments the biaxially-stretched PET film into multiple strips in the widthwise direction, then bonds these strips together in the lengthwise direction to form a single continuous material film. This segmentation approach allows efficient production while maintaining consistent fast axis orientation across the entire film, as all segments originate from the same parent film with uniformly oriented fast axes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention combines multiple divided strips into a single continuous material film by bonding them together. This merging process creates a unified film structure where the fast axes of all constituent substrates remain parallel, solving the alignment problem while maintaining production efficiency.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If conventional methods are used to divide and bond substrates from different areas, then production can proceed, but the optical axis orientations become misaligned requiring complex measurement and determination of fast axes

Engineering Contradiction:
Improveproduction process feasibilityVSAvoidfast axis measurement and determination complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The invention performs preliminary action by bonding the strips together while they still retain their original relative orientations from the parent film. This preliminary bonding ensures that the fast axes remain parallel before any cutting or further processing, eliminating the need for subsequent measurement and determination of fast axis orientations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The material film structure itself provides the alignment function. By constructing the film from segments of a single biaxially-stretched parent film, the fast axis orientation alignment is inherent to the material structure, eliminating the need for external measurement and determination processes.

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If substrates are cut from adjacent areas in the widthwise direction and bonded in symmetric arrangement, then curling when heated can be reduced, but the optical axis orientations remain substantially misaligned

Engineering Contradiction:
Improvethermal stability reducing curlingVSAvoidoptical axis orientation alignment
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The invention changes the bonding dimension from widthwise (transverse direction) to lengthwise (machine direction). By bonding strips in the lengthwise direction rather than arranging them symmetrically in the widthwise direction, the fast axes remain parallel while thermal stability is maintained through the continuous film structure.

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

The method effectively minimizes fast axis misalignment between substrates, facilitating mass production of touch sensing devices with improved optical properties and reduced production complexity.

Implementation Method 1

a material film, the material film being biaxially stretched and including an available area that is a partial area in a widthwise direction of the material film

Methodology Applied
Scientific EffectBiaxial stretching: Deformation

Data Source

PatentEP3299944B1Method for manufacturing touch sensing device and touch sensing device
Publication Date: 2020.09.30 HOSIDEN CORP
  • EP3299944B1 patent drawingFigure 1A~1B
  • EP3299944B1 patent drawingFigure 2
  • EP3299944B1 patent drawingFigure 3A

AI summary

A method for manufacturing a touch sensing device with minimized misalignment of the fast axes of two bonded substrates and suitable for mass production. The method includes the following steps 1) to 5). 1) Preparing a biaxially-stretched material film F. The material film F includes an available area F1 being an area in the widthwise direction and extends in the lengthwise direction. The available area F1 includes a first segment F11 and a second segment F12 that define different areas in the lengthwise direction. 2) Forming an electrode group on one of the first and second segment F11, F12. 3) Cutting a first piece P1 out of the material film F to make the first piece including the first segment F11. 4) Cutting a second piece P2 out of the material film F to make the second piece including the second segment F12. 5) Bonding the first segment F11 to the second segment F12 substantially maintaining orientations of the first and second segment F11, F12 as before the cutting.