Touch Panel Eliminating OCA Adhesive for High Transmittance
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Solution Overview
Problem
Touch panels face issues with low light transmittance and high manufacturing costs due to the use of optically clear adhesive (OCA) and multiple stack structures, which can lead to bonding defects and increased expenses from imported transparent electrode films.
Innovation Solution
A touch panel design where the outer dummy layer and transparent electrode are formed on the same substrate, eliminating the need for OCA and simplifying the stack structure, with an intermediate layer for index matching to enhance transmittance and visibility, and optionally incorporating an anti-reflective layer to improve light transmittance and reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If OCA (optically clear adhesive) is used to bond substrate and transparent electrode film, then bonding is achieved, but workability deteriorates and bonding defects occur
Solution Approach 1:
The patent removes the OCA layer from the touch panel structure, directly bonding the transparent electrode film to the substrate without the adhesive intermediary. This extraction of the problematic OCA component eliminates bonding defects and improves workability while maintaining reliable adhesion through direct contact between the substrate and transparent electrode film.
2Reliability
If multiple stack structure of film and substrate is used, then touch panel functionality is achieved, but light transmittance is lowered
Solution Approach 1:
The patent employs ultra-thin film structures for both the substrate and transparent electrode film, minimizing the cumulative thickness of the stack. By using thin films with optimized optical properties and reducing the number of intermediate layers, the structure maintains necessary mechanical strength and electrical functionality while maximizing light transmittance.
3Reliability
If transparent electrode film is obtained through importation, then quality is ensured, but manufacturing cost is increased
Solution Approach 1:
The patent adopts a disposable transparent electrode film that can be directly applied to the substrate without requiring expensive imported materials. The film is designed to be single-use, eliminating the need for complex quality assurance processes and expensive material imports, thereby significantly reducing manufacturing costs while maintaining adequate performance for the application.
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 design reduces defect rates, improves light transmittance, and lowers manufacturing costs by eliminating the need for OCA and simplifying the stack structure, while enhancing visibility and reducing the visibility of the transparent electrode, achieving light transmittance of up to 99% and maintaining high reliability.
Implementation Method 1
the intermediate layer capable of performing the index matching is interposed between the substrate and the transparent electrode, so that the transmittance, reflectance and yellowish characteristics can be improved
Implementation Method 2
the anti-reflective layer is deposited on the transparent electrode after the transparent electrode has been deposited on the substrate, so that the anti-reflection efficiency and the light transmittance can be improved
Data Source
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AI summary
A touch panel according to the embodiment includes a substrate having a first surface and a second surface opposite to the first surface; an intermediate layer on the first surface of the substrate; and a transparent electrode on the intermediate layer. A touch panel according to another embodiment includes a substrate having a first surface and a second surface opposite to the first surface; a transparent electrode on the first surface of the substrate; and an anti-reflective layer on the transparent electrode.