Transparent Touch Panel Body with Structured Conductive Film
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Solution Overview
Problem
Existing transparent bodies for touch screen panels face challenges in maintaining stability and proper light transmission while providing enhanced electrical characteristics, particularly for large displays, where conventional designs often compromise on optical and electrical performance.
Innovation Solution
A process involving the deposition of a transparent layer stack with dielectric films of varying refractive indices, combined with a structured transparent conductive film and a transparent adhesive, is used to create a stable and high-quality transparent body for touch screen panels, ensuring optimal light transmission and reduced electrical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transparent body with increased thickness and robust structure is used to withstand multiple contacts and harsh conditions, then reliability is improved, but light transmission in the visible spectrum is compromised
Solution Approach 1:
The transparent body is segmented into multiple functional layers including a substrate, barrier layer, transparent conductive layer, and optional index matching layer. This segmentation allows each layer to be optimized for its specific function - the barrier layer provides robustness and reliability, while the transparent conductive layer maintains electrical functionality, and the index matching layer optimizes optical transmission by reducing reflections at interfaces.
Solution Approach 2:
The transparent body employs composite material structures combining different materials with complementary properties. The barrier layer uses materials like silicon oxide or silicon nitride for chemical stability and protection, the transparent conductive layer uses materials like ITO or AZO for electrical conductivity and transparency, and the index matching layer uses materials with specific refractive indices to optimize optical performance. This composite approach allows simultaneous achievement of reliability and light transmission.
2Measurement precision
If a structured transparent conductive layer is used to enable capacitance measurement for touch detection, then touch sensing functionality is improved, but optical appearance and light transmission are degraded
Solution Approach 1:
The transparent conductive layer is structured with locally varying properties - it has different patterns, thicknesses, or material compositions in different regions to optimize capacitance measurement for touch detection while maintaining good optical appearance. The structuring allows the conductive layer to perform its measurement function in specific areas without compromising the overall optical transmission and appearance of the transparent body.
Solution Approach 2:
An index matching layer is introduced as an intermediary between the structured transparent conductive layer and the external environment. This intermediate layer compensates for the optical disturbances caused by the structured conductive layer, reducing reflections and improving light transmission. The index matching layer acts as a mediator that allows the structured conductive layer to maintain its measurement precision while minimizing its negative impact on optical appearance.
3Illumination intensity
If thin film based structures are used to achieve invisible appearance, then optical performance is improved, but electrical characteristics and conductivity are compromised
Solution Approach 1:
The electrical and optical parameters of the transparent conductive layer are carefully optimized and adjusted. By changing parameters such as layer thickness, material composition, and deposition conditions, the patent achieves a balance where the thin film structure maintains good optical performance (high transparency) while providing sufficient electrical conductivity for touch sensing functionality. The sheet resistance is controlled within specific ranges to ensure adequate electrical characteristics.
Solution Approach 2:
Composite material structures are used to compensate for the limitations of thin films. Multiple layers with different materials and properties are combined - the transparent conductive layer provides both optical transparency and electrical conductivity, while the barrier layer and index matching layer provide additional functional benefits. This composite approach allows thin film based structures to achieve invisible appearance while maintaining reliable electrical characteristics through the synergistic combination of multiple materials.
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 approach results in a transparent body that maintains stability and performance over time, with improved optical and electrical characteristics, making it suitable for large-area touch panels without compromising light transmission or visibility.
Implementation Method 1
depositing a first transparent layer stack over a transparent substrate, wherein said first transparent layer stack includes at least a first dielectric film with a first refractive index and a second dielectric film with a second refractive index
Implementation Method 2
providing a structured transparent conductive film, and wherein the structured transparent conductive film corresponds to a sheet resistance of 100 Ohm/square or below
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3D
AI summary
A process for manufacturing a transparent body for use in a touch screen panel is provided. The process includes: depositing a first transparent layer stack (12) over a transparent substrate (14), wherein said first transparent layer stack (12) includes at least a first dielectric film (16) with a first refractive index, and a second dielectric film (18) with a second refractive index different from the second the first refractive index; providing a structured transparent conductive film (22) in a manner such that the first transparent layer stack (12) and the transparent conductive film (22) are disposed over the substrate (14) in this order, and wherein the structured transparent conductive film has a sheet resistance of 100 Ohm/square or below; and providing a transparent adhesive onto the structured transparent conductive film configured for attaching the layer stack to the touch screen panel.