Dry Polymeric Coating for Conductive Patterns
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Solution Overview
Problem
Current touch screen technologies face challenges with the fragility, limited supply, and low conductivity of Indium Tin Oxide (ITO) coatings, as well as issues with crosslinkable materials used in protective coatings, such as photoinitiators causing yellowing, adhesion problems, and shrinkage, particularly in high-speed printing processes.
Innovation Solution
A method involving the formation of electrically-conductive patterns on transparent substrates with a dry outermost polymeric coating that is non-crosslinked, having a thickness of less than 5 μm, an integrated transmittance of at least 80%, and a glass transition temperature of 65°C or higher, which eliminates the need for curing and reduces complexity, avoiding issues with photoinitiators and adhesion problems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If crosslinkable materials (photocurable compositions) are used for protective coatings, then protective properties are improved, but yellowing, adhesion problems, and shrinkage occur due to photoinitiators
Solution Approach 1:
The patent removes photoinitiators and crosslinking agents from the protective coating composition, extracting the harmful elements that cause yellowing and adhesion problems while retaining the protective function through simple drying of thermoplastic polymer coatings
Solution Approach 2:
The patent uses simple thermoplastic polymer coatings that dry without curing, replacing complex photocurable systems. These coatings provide sufficient protection without the need for photoinitiators, eliminating yellowing and adhesion issues associated with crosslinkable materials
2Reliability
If ITO coatings are used for electrically-conductive films, then conductivity is achieved, but fragility and limited supply are problems
Solution Approach 1:
The patent changes the material composition from brittle ITO to flexible metallic compositions (such as aluminum, copper, or silver nanowires), transforming the physical properties while maintaining electrical conductivity. This substitution eliminates fragility and supply limitations associated with ITO
3Reliability
If protective coatings are applied to protect from environmental damage, then protection is improved, but manufacturing complexity increases
Solution Approach 1:
The patent removes the curing step and photoinitiator system from the coating process, extracting the sources of manufacturing complexity. The simplified process applies thermoplastic polymer coatings that dry without requiring UV irradiation or chemical crosslinking, reducing manufacturing steps and complexity
Data Source
AI summary
A method is used to provide an electrically-conductive article. This method includes: forming an electrically-conductive pattern on first supporting side of a transparent substrate that also comprises an opposing second supporting side; and forming a dry outermost polymeric coating over at least part but not all of the electrically-conductive pattern, the dry polymeric coating having a dry thickness of less than 5 μm, an integrated transmittance of at least 80%, and comprising a non-crosslinked thermoplastic polymer having a glass transition temperature (Tg) that is equal to or greater than 65° C.