Transparent Electroconductive Film Surface Roughness Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Transparent electroconductive films used in touch sensors and displays face challenges in maintaining antiblocking properties while reducing haze, which affects display quality during roll-to-roll manufacturing due to surface roughness issues.
Innovation Solution
A transparent electroconductive film configuration with a transparent substrate and a transparent electroconductive coating, where the arithmetic mean surface roughness on the coated side is kept low and the uncoated side is roughened, using a first and second cured resin layer with spherical particles, to achieve antiblocking and improved transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fine irregularities are formed in the plastic film substrate to improve antiblocking properties, then sliding properties and antiblocking properties are improved, but light scattering due to the irregularities causes an increase in haze, which impairs transparency
Solution Approach 1:
The invention divides the substrate surface into two distinct regions: the first surface (electroconductive coating side) is kept smooth with low roughness (Ra ≤ 10 nm) to maintain transparency, while the second surface (opposite side) is made rough with higher roughness (Ra > 5 nm) to provide antiblocking properties. This segmentation allows each surface to independently fulfill its specific function without interfering with the other.
Solution Approach 2:
Different surface qualities are applied to different surfaces of the substrate. The first surface has a smooth local quality optimized for optical transparency and electroconductive coating adhesion, while the second surface has a rough local quality optimized for preventing film blocking during winding. Each surface's quality is locally optimized for its specific functional requirement.
2Reliability
If the surface of the transparent electroconductive coating side is roughened to improve antiblocking properties, then sliding properties are improved, but haze on the transparent electroconductive coating side increases, which deteriorates display quality
Solution Approach 1:
The invention segments the antiblocking function from the optical function by applying surface roughness only to the non-optical surface (second surface). The electroconductive coating surface (first surface) maintains smoothness to ensure high display quality, while the opposite surface provides antiblocking functionality through controlled roughness.
Solution Approach 2:
The surface quality is locally differentiated between the two surfaces of the substrate. The first surface maintains a smooth local quality (Ra ≤ 10 nm) to minimize light scattering and ensure high display quality, while the second surface has a rough local quality (Ra > 5 nm) specifically for antiblocking properties during manufacturing and handling.
Data Source
AI summary
Provided are: a transparent electroconductive film with good transparency, wherein the transparent electroconductive film has antiblocking properties that can withstand roll-to-roll manufacturing, and white haze on the transparent electroconductive film side is reduced. Also provided is a touch sensor in which the transparent electroconductive film is used. This transparent electroconductive film includes a transparent substrate 1 and a transparent electroconductive film 13 formed on one side of the transparent substrate, wherein the arithmetic mean surface roughness Ra in a 452×595 μm field of view on the surface of the transparent electroconductive film 13 is greater than 0 nm and no more than 10 nm, and the arithmetic mean surface roughness Ra in a 452×595 μm field of view on the surface of the transparent substrate 1 on which the transparent electroconductive film 13 is not formed is greater than 5 nm and less than 100 nm.