Cover Window Printing Layer Transfer via Adhesive Film

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Solution Overview

Problem

Existing methods for creating a touch screen panel cover window with various colors and effects are limited by the difficulty in mass-producing such designs, especially when using tempered glass, as direct application of ink onto the glass complicates the process.

Innovation Solution

A printing layer is formed on a separate transfer substrate and then transferred to a cover window substrate using an adhesive film layer, allowing for the creation of a bezel area with defined view areas, enabling the use of various colors and effects while overcoming processing constraints associated with tempered glass handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If direct ink application onto tempered glass is used, then various colors and effects can be achieved, but the manufacturing process becomes complex and difficult to mass-produce

Engineering Contradiction:
Improvevarious colors and effectsVSAvoidmanufacturing process complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The manufacturing process is divided into separate stages: first forming the printing layer on a transfer substrate, then transferring it to the cover window substrate. This segmentation allows each stage to be optimized independently, simplifying the overall manufacturing process while maintaining design flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The printing layer is formed in advance on a transfer substrate before being transferred to the final cover window substrate. This preliminary action enables the printing layer to be prepared separately with various colors and effects, then applied to the substrate in a controlled manner, reducing manufacturing complexity.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If a transfer method with adhesive film layer is used, then mass production becomes feasible, but additional process steps are required

Engineering Contradiction:
Improvemass production capabilityVSAvoidprocess steps
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The adhesive film layer is integrated with the transfer substrate to form a single transfer assembly. This merging reduces the number of separate components and simplifies the transfer process, enabling mass production while managing process complexity through consolidation of functions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The adhesive film layer serves as an intermediary between the printing layer and the cover window substrate. It facilitates the transfer process by providing controlled adhesion, allowing the printing layer to be transferred efficiently en masse while managing the complexity of the bonding process through a dedicated intermediary material.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If adhesive film layer thickness is increased to enforce adhesive force, then transfer reliability improves, but the overall window thickness increases

Engineering Contradiction:
Improvetransfer reliabilityVSAvoidwindow thickness
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The adhesive film layer thickness is optimized within a specific range (10-100 μm) to achieve the necessary adhesive force for reliable transfer while minimizing the increase in overall window thickness. This parameter optimization balances transfer reliability with the constraint of maintaining a thin profile.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The adhesive film layer is applied specifically where needed to enforce adhesive force during transfer, rather than uniformly throughout the entire structure. This localized application ensures reliable transfer at the printing layer interface while minimizing unnecessary material addition and thickness increase in other areas.

Inventive Principle:
Principle #3Local quality

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 method allows for the mass production of touch screen panel cover windows with various colors and effects by facilitating the transfer of a printing layer onto a transparent plastic or tempered glass substrate, enhancing the manufacturing efficiency and design flexibility.

Implementation Method 1

the adhesive film layer has a thickness enforcing adhesive force which enables transfer of the printing layer by making adhesiveness between the adhesive film layer and the cover window substrate higher than adhesiveness between other separately prepared substrate and the printing layer

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3144782B1Cover window for touch screen panel formed with printing layer and method for forming printing layer on cover window for touch screen panel
Publication Date: 2020.10.14 LG CHEM LTD
  • EP3144782B1 patent drawingFigure 1~2
  • EP3144782B1 patent drawingFigure 3
  • EP3144782B1 patent drawingFigure 4~5B

AI summary

The present invention provides a cover window for a touch screen panel, wherein a printing layer is formed at an edge of the transfer substrate film, and an area where the printing layer is not formed is removed from the transfer film, which forms a view area in the cover window substrate.