Composite Optical Adhesive Layer for Display Lamination

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Solution Overview

Problem

Existing touchscreen assembly laminating processes face challenges with residual air bubbles and poor optical quality due to the limitations of solid and liquid optical adhesives, including difficulty in filling irregular geometric seams and high equipment costs.

Innovation Solution

A display device with a composite optical adhesive layer, featuring an edge adhesive layer with specific Shore hardness and a conformal adhesive layer with greater compressibility, which are used in combination to improve adhesion and optical quality by filling seams effectively without the need for debubbling and reducing equipment costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If solid optical adhesive is used for lamination, then the adhesive provides structural support, but it cannot fill irregular geometric seams and corners effectively, resulting in residual air bubbles and poor optical quality

Engineering Contradiction:
Improveoptical qualityVSAvoidfilling capability
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent changes the physical state parameter of the optical adhesive from solid to liquid, enabling it to flow and fill irregular geometric seams, corners, and edges that solid adhesive cannot penetrate, thereby eliminating residual air bubbles and improving optical quality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite optical adhesive system consisting of liquid optical adhesive combined with a conformal adhesive layer, where the liquid adhesive fills gaps and the conformal layer provides structural support and surface quality, achieving both filling capability and optical quality

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If liquid optical adhesive is used for lamination, then the adhesive can fill gaps effectively, but it requires hollow cavity for filling and temporary dam structure, increasing equipment cost and process complexity

Engineering Contradiction:
Improvegap filling capabilityVSAvoidequipment cost
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the need for hollow cavity formation and temporary dam structures by using liquid optical adhesive that can be applied directly and conform to the gap geometry, simplifying the equipment requirements and process steps

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The liquid optical adhesive automatically flows and fills the gap geometry without requiring external dam structures or complex positioning mechanisms, as the adhesive self-conforms to the irregular geometric seams and corners through its fluidity

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If liquid optical adhesive is used for lamination, then the adhesive can fill gaps, but the curing process is very long and quality control is difficult, reducing productivity

Engineering Contradiction:
Improveadhesive filling qualityVSAvoidcuring time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent changes the curing parameters by using UV-curable liquid optical adhesive that cures rapidly upon exposure to UV light, reducing curing time from hours to minutes and enabling better quality control through controlled UV exposure timing

Inventive Principle:
Principle #35Parameter changes

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 composite adhesive layer effectively fills irregular seams and improves optical quality by reducing air bubbles and internal stress, enhancing the yield and performance of the display device.

Implementation Method 1

a conformal adhesive layer configured between the display module and the upper module, having a third Shore hardness less than the Shore hardness and covering a part of the display surface

Methodology Applied
Scientific EffectCompressibility: Compression

Implementation Method 2

an edge adhesive layer having a Shore hardness and configured in a part of the edge area and between the display module and the upper module

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP4318111A1Display device having compound optical adhesive layer
Publication Date: 2024.02.07 LUCENT ADVANCED MATERIAL CORP
  • EP4318111A1 patent drawingFigure 1
  • EP4318111A1 patent drawingFigure 2~4
  • EP4318111A1 patent drawingFigure 5~7

AI summary

The present invention relates to a display device (100), which is assembled by an adhesive bonding process. The display device (100) includes: a display module (110) comprising an edge area (EA1), a front surface (115) facing toward an upper module (120), a display surface (DF) incorporated into the front surface (115) and displaying a digital content; the upper module (120) comprising the edge area (EA2) and configured above the display module (110); an edge adhesive layer (130) having a Shore hardness and configured in a part of the edge area (EA) and between the display module (110) and the upper module (120); and a conformal adhesive layer (140) configured between the display module (110) and the upper module (120), having a Shore hardness less than the Shore hardness of the edge adhesive layer (130) and covering a part of the display surface (DF).