Touch-Sensing Cover With Embedded Shielding Layer
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Solution Overview
Problem
Conventional touch-sensing devices with nanowire electrodes face issues such as cracks, defects, and electrical resistance variations due to the large taper angle of the shielding layer, which also reduces flexibility and increases complexity in photolithography, and bonding strength between the shielding layer and the cover.
Innovation Solution
A touch-sensing cover with an embedded shielding layer is fabricated by forming a shielding layer on a carrier plate, followed by a substrate that covers and embeds the shielding layer, creating a coplanar surface with low surface roughness, thereby eliminating the climbing structure and ensuring uniform electrical and optical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a nanowire layer is applied on a cover with a protrusion structure of the shielding layer, then the shielding layer achieves sufficient optical density to shield peripheral traces, but the nanowire layer develops cracks, defects and breaks due to large taper angle
Solution Approach 1:
The patent applies a primer layer to the cover surface before depositing the nanowire layer. This preliminary action modifies the surface properties to reduce the taper angle effect, preventing cracks and defects in the nanowire layer while maintaining the shielding effectiveness of the underlying shielding layer structure.
Solution Approach 2:
The primer layer acts as an intermediary between the protrusion structure of the shielding layer and the nanowire layer. It mediates the interface by reducing the taper angle, thereby preventing direct contact issues between the nanowire layer and the sharp protrusions, eliminating cracks and defects.
2Object-affected harmful factors
If the shielding layer is made thicker to achieve sufficient optical density, then shielding performance improves, but the taper angle increases causing cracks and defects in the nanowire layer
Solution Approach 1:
The primer layer is applied beforehand to modify the surface geometry or properties, reducing the effective taper angle that the nanowire layer encounters. This allows the shielding layer to maintain its thicker profile for optical density while the primer layer prevents the manufacturing defects that would otherwise result from the large taper angle.
3Object-affected harmful factors
If a conventional shielding layer structure is used, then shielding function is achieved, but photolithography complexity increases due to large taper angle
Solution Approach 1:
The primer layer is applied as a preliminary step that modifies the surface to reduce the taper angle. This simplifies subsequent photolithography processes by providing a more uniform surface for photoresist application and pattern formation, reducing the complexity of the overall manufacturing process while maintaining shielding function.
4Object-affected harmful factors
If the shielding layer is printed on the cover, then shielding is achieved, but bonding strength reduces flexibility
Solution Approach 1:
The primer layer is applied beforehand to create a more compliant interface between the shielding layer and the cover. This preliminary modification allows the shielding layer to maintain its bonding strength while the primer layer absorbs some of the mechanical stress, preserving the flexibility required for modern flexible touch panel specifications.
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 solution provides a flexible touch-sensing cover with high uniformity in electrode characteristics, reducing electrical resistance differences and improving manufacturing yield, while maintaining flexibility and optical performance, capable of withstanding 100,000 bends at a bending radius of 2.5 millimeters.
Implementation Method 1
The curing step includes an exposure curing or a thermal curing
Implementation Method 2
The curing step includes an exposure curing or a thermal curing
Data Source
AI summary
Covers for touch-sensing devices include a shielding layer; and a substrate, in which the substrate covers the shielding layer, and the substrate and the shielding layer are integrated and form a coplanar surface. The coplanar surface is a smooth surface, which has a surface roughness Ra in a range from about 0.05 μm to about 0.5 μm.