Gel-Based Optical Adhesive for Touch Screen Lamination
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Solution Overview
Problem
Conventional touch screen lamination technologies face challenges with air gaps, bubbles, and optical defects due to the limitations of solid and liquid optical adhesives, such as difficulty in filling irregular gaps and requiring additional processing steps like defoaming and curing, which increase processing time and cost.
Innovation Solution
The use of a pre-cured gel-based optical adhesive that maintains a fixed shape without external disturbance, allowing it to fill irregular gaps between the touch panel and display module without overflowing, eliminating the need for a defoaming step and reducing processing time by maintaining adhesion strength and optical quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If solid optical adhesive is used to fill the gap between touch panel and display module, then adhesion strength is improved, but manufacturing precision deteriorates due to difficulty in filling irregular gaps and corners completely
Solution Approach 1:
The patent changes the physical state of the optical adhesive from solid to gel form. The gel adhesive has intermediate properties between solid and liquid, allowing it to flow into irregular gaps and corners while maintaining sufficient adhesion strength. This parameter change resolves the contradiction by enabling complete gap filling without sacrificing bonding capability.
Solution Approach 2:
The patent utilizes the phase transition characteristics of gel adhesive, which can transition between more fluid and more solid states depending on conditions. During application, the gel flows to fill gaps completely, then sets to provide strong adhesion. This phase transition capability allows the material to satisfy both complete gap filling and strong bonding requirements.
2Manufacturing precision
If liquid optical adhesive is used to fill the gap, then manufacturing precision is improved by completely filling irregular gaps, but device complexity increases due to additional defoaming and curing steps
Solution Approach 1:
The patent changes the viscosity and flow characteristics of the adhesive to gel form, which maintains the ability to fill gaps completely like liquid adhesive but eliminates the need for defoaming steps. The gel's intermediate fluidity allows complete gap filling while its gel structure prevents bubble formation and entrapment, simplifying the manufacturing process.
Solution Approach 2:
The patent extracts and eliminates the problematic liquid state characteristics (bubble formation, defoaming requirements) while retaining the beneficial gap-filling capability. By using gel adhesive instead of liquid adhesive, the patent removes the need for complex defoaming and curing processes, simplifying the overall manufacturing procedure.
3Strength
If solid optical adhesive is used, then adhesion strength is maintained, but productivity deteriorates due to additional defoaming step required
Solution Approach 1:
The patent changes the adhesive from solid to gel form, which maintains adhesion strength while eliminating the need for time-consuming defoaming steps. The gel's unique rheological properties allow it to be applied and set quickly without requiring additional processing time for bubble removal, thereby improving productivity while maintaining bonding strength.
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 gel-based adhesive ensures a bubble-free, high-transmittance touch screen with improved optical characteristics and enhanced adhesive strength, reducing manufacturing time and cost by eliminating the need for additional curing and defoaming processes.
Implementation Method 1
a pre-cured gel-based optical adhesive that maintains a fixed shape without external disturbance, allowing it to fill irregular gaps between the touch panel and display module
Implementation Method 2
having a coverage larger than the displaying area and less than an outer edge of the frame and a ratio of transmittance larger than a percent of 91%
Data Source
AI summary
The present invention relates to a touch screen that is assembled by a bonding process. The touch screen includes a display module including a frame and a displaying area; a touch panel configured above the display module and to receive a touch input; and a gel-based optical adhesive partially pre-cured prior to an implementation of the bonding process, interposed between and bonding the display module and the touch panel, and having a coverage larger than the displaying area and less than an outer edge of the frame and a ratio of transmittance larger than a percent of 91%.