Touchscreen Through-Hole Adhesive Flatness Control
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Solution Overview
Problem
Resistive touchscreens face challenges in maintaining flatness and aesthetic appeal due to variations in the amount of electrically conductive adhesive supplied, leading to uneven substrate flexure and impaired surface quality.
Innovation Solution
The implementation of a through hole in the second substrate to connect the first and second wiring layers with an electrically conductive adhesive, ensuring consistent and controlled wiring connections, and using a decorative printing layer to conceal the adhesive, maintaining the touchscreen's flatness and appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrically conductive adhesive is supplied to connect wiring layers, then electrical connection is achieved, but variations in adhesive amount cause uneven substrate flexure and surface quality degradation
Solution Approach 1:
The patent divides the adhesive application into two distinct stages: first applying adhesive to the lower substrate before stacking, then supplying additional electrically conductive adhesive through through-holes after stacking. This segmentation allows each adhesive application to serve a specific function - the first for bonding substrates, the second for electrical connection - thereby preventing the trade-off between connection reliability and surface flatness.
Solution Approach 2:
The patent introduces through-holes as intermediary structures that enable precise delivery of electrically conductive adhesive to specific locations between wiring layers. These through-holes act as controlled channels that limit adhesive spread and ensure consistent application amounts, eliminating the variations that cause substrate flexure and surface quality issues.
2Reliability
If adhesive is supplied to connect wiring layers, then wiring connection is achieved, but adhesive-related flexure impairs aesthetic appearance
Solution Approach 1:
The patent separates bonding function from electrical connection function by applying adhesive in two stages. The first adhesive application handles substrate bonding, while the second application through through-holes handles electrical connection. This segmentation prevents the harmful flexure effect because the electrical connection adhesive is applied in controlled, localized amounts through pre-formed holes, eliminating the uneven distribution that causes aesthetic degradation.
Solution Approach 2:
The patent performs preliminary actions by forming through-holes in the lower substrate before the final assembly step. This preliminary structuring of the substrate allows controlled adhesive application later, preventing the harmful flexure effect that would otherwise occur from uncontrolled adhesive spread. The through-holes are prepared in advance to guide adhesive placement precisely where needed.
3Manufacturing precision
If through hole is formed in second substrate, then controlled adhesive supply is achieved, but manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary action by forming through-holes in the lower substrate during early manufacturing stages, before final assembly. This advance preparation simplifies the overall process because the through-holes are already in place to guide adhesive application, eliminating the need for complex real-time adhesive dispensing systems. The preliminary structuring enables precise adhesive control without adding complexity to the final assembly operations.
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 solution enhances the quality and functionality of resistive touchscreens by maintaining flatness and aesthetic appeal, improving the operational area while preventing adhesive-related flexure issues.
Implementation Method 1
The electrically conductive adhesive is provided in the through hole, and connects the first wiring layer and the second wiring layer
Implementation Method 2
The adhesive adheres the first and second substrates to each other
Data Source
AI summary
A touchscreen includes a first substrate, a second substrate, an adhesive, a first wiring layer, a second wiring layer, a through hole, and an electrically conductive adhesive. The first substrate includes a first transparent conductive film formed at a surface of the first substrate. The second substrate includes a second transparent conductive film formed at a surface of the second substrate. The adhesive adheres the first and second substrates to each other. The first wiring layer is formed on the surface of the first substrate. The second wiring layer is formed on the surface of the second substrate. The through hole pierces through the second substrate. The electrically conductive adhesive is provided in the through hole, and connects the first wiring layer and the second wiring layer.