Curved Touch Panel Using Ductile Wire Electrodes
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Solution Overview
Problem
Conventional transparent conductive films made of ITO or IZO are inflexible, prone to cracking, and difficult to form into curved surfaces, limiting the applicability of touch panels to flat surfaces, which is inadequate for mobile devices.
Innovation Solution
A touch panel with a curved surface shape using ductile wire materials for electrodes, allowing the formation of a curved surface without disconnection through thermoforming, and featuring multiple input regions with different curvatures for tactile discrimination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If transparent conductive film made of ITO or IZO is used, then high light transmittance is achieved, but the film is hard, susceptible to deformation, and lacks flexibility
Solution Approach 1:
The patent changes the material parameter from brittle transparent conductive oxide (ITO/IZO) to ductile wire material, fundamentally altering the mechanical properties while maintaining electrical conductivity. This enables the touch panel to be formed into curved surfaces without cracking or deformation.
Solution Approach 2:
The patent uses composite material structure where ductile wire materials are arranged in a grid pattern to form electrodes. This composite approach combines the ductility of metal wires with the transparency requirements, creating a flexible yet conductive electrode system suitable for curved surfaces.
2Illumination intensity
If ITO or IZO transparent conductive film is used, then high light transmittance is achieved, but low resistance is contradictory to high light transmittance
Solution Approach 1:
The patent changes the electrical resistance parameter by using ductile wire materials with inherently lower resistivity compared to thin-film ITO/IZO. The wire material's superior electrical conductivity is achieved without compromising light transmittance, as the wire grid structure allows light to pass through the spaces between wires.
Solution Approach 2:
The patent applies local quality by using wire materials specifically in the electrode regions where electrical conductivity is critical, while maintaining transparency in the spaces between wires. This localized approach optimizes both electrical performance and optical properties in different areas of the touch panel.
3Ease of manufacture
If flat surface input region is used, then manufacturing is simplified, but the applicable range is limited and cannot accommodate curved surfaces
Solution Approach 1:
The patent explicitly adopts curved surface geometry for the touch panel input region, moving away from traditional flat surfaces. The ductile wire material electrodes are arranged to conform to the curved surface, enabling the touch panel to be mounted on various shaped displays and expanding its applicability to curved and flexible displays.
Solution Approach 2:
The patent changes the geometric parameter of the input region from flat to curved surface. This geometric transformation is made possible by the ductile wire material's ability to bend and conform to curved surfaces without cracking, thereby expanding the range of applicable surface shapes while maintaining manufacturing feasibility.
4Adaptability or versatility
If ductile wire material is used for electrodes, then curved surface formation without disconnection is achieved, but material selection is more restricted
Solution Approach 1:
The patent changes the material property parameter from brittle to ductile, selecting materials that can withstand bending and forming into curved surfaces. The specified materials (Au, Ag, Cu, Al, electroconductive carbon, or electroconductive organic compounds) all share the property of ductility, which enables curved surface formation while maintaining electrical connectivity.
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
Enables the creation of flexible touch panels with curved surfaces, enhancing usability and reducing the risk of misoperation by allowing tactile recognition of input regions, while maintaining high light transmittance and conductivity.
Implementation Method 1
a flat sheet can be formed into any curved surface shape by thermoforming without fear of disconnection
Data Source
AI summary
Provided is a touch panel having a curved surface. A touch panel 10 is formed of a sheet of a flat sheet 1 by thermoforming. A plurality of island-like electrodes 2,3 is arrayed in each of an X direction and a Y direction on the input region. The island-like electrodes 2, 3, inter-electrode wires 4, and a lead wiring are formed of a ductile wire material. A center portion of the flat sheet 1 is formed into a convex dome shape by thermoforming. The touch panel 10 includes a first input region 11 and a second input region 12. The first input region 11 is provided on the convex dome shape. The second input region 12 is provided on the flat surface (zero curvature). The first input region 11 is provided at around a center on the inside of the second input region 12.