Narrow-Frame Touch Sheet Anti-Corrosion via Visor Resist Layer
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Solution Overview
Problem
Existing methods for manufacturing narrow frame touch input sheets with double-layer transparent conductive film patterns face challenges in achieving precise metal film formation for electric resistance requirements and productivity, especially when forming thin lines, and require laminating two sheets for both-sided metal and transparent electrode formation, leading to decreased transmittance and bulkiness.
Innovation Solution
A method involving sequential lamination of transparent and light blocking conductive films with resist layers on both sides of a transparent base sheet, followed by simultaneous patterning and etching to form electrode and wiring patterns without misregistration, and applying a second resist layer as an anticorrosion layer to cover fine wiring circuit patterns, except at terminal portions, ensuring accurate registration and improved anticorrosion properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a second photoresist film is formed and patterned on the patterned metal film to achieve precise metal film formation, then the metal film can be patterned with desired electric resistance, but if mask position deviates even slightly, one metal film becomes thin while the other becomes thick, causing the metal film to not have the desired electric resistance
Solution Approach 1:
The patent applies preliminary action by forming a protective resin layer on the metal film before patterning the second photoresist film. This protective layer is formed in advance to prevent mask position deviation from affecting metal film thickness, ensuring consistent electric resistance. The protective layer acts as a buffer that decouples the patterning precision from the final metal film dimensions.
2Adaptability or versatility
If two touch input sheets are laminated and glued to each other to form both-sided metal and transparent electrode patterns, then the capacitance type touch sensor can be manufactured, but productivity decreases, transmittance of transparent window portion decreases, and bulkiness increases due to increased thickness
Solution Approach 1:
The patent merges the formation of both-sided metal films and transparent electrode patterns into a single touch input sheet structure. By forming all patterns on one substrate without laminating two separate sheets, the manufacturing process is simplified, productivity is improved, and the final product has reduced thickness and higher transmittance while maintaining the required both-sided electrode functionality.
3Adaptability or versatility
If two touch input sheets are laminated and glued to each other to form both-sided metal and transparent electrode patterns, then the capacitance type touch sensor can be manufactured, but the transmittance of the transparent window portion decreases
Solution Approach 1:
The patent merges the formation of both-sided metal films and transparent electrode patterns into a single touch input sheet structure. By forming all patterns on one substrate without laminating two separate sheets, the final product has reduced thickness and higher transmittance while maintaining the required both-sided electrode functionality.
4Adaptability or versatility
If two touch input sheets are laminated and glued to each other to form both-sided metal and transparent electrode patterns, then the capacitance type touch sensor can be manufactured, but bulkiness increases due to an increase in thickness
Solution Approach 1:
The patent merges the formation of both-sided metal films and transparent electrode patterns into a single touch input sheet structure. By forming all patterns on one substrate without laminating two separate sheets, the final product has reduced thickness and higher transmittance while maintaining the required both-sided electrode functionality.
5Ease of manufacture
If no anticorrosion layer is applied to the fine wiring circuit pattern, then the manufacturing process is simpler, but the metal film does not have good anticorrosion property and cannot maintain low resistance for long periods under harsh conditions
Solution Approach 1:
The patent merges the protective resin layer formation with the second photoresist film patterning step into a single process. The same photoresist film that defines the wiring pattern also serves as the anticorrosion protective layer, eliminating the need for a separate anticorrosion layer and simplifying the manufacturing process while ensuring good corrosion resistance and long-term reliability.
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 method enables the production of narrow frame touch input sheets with excellent anticorrosion properties, maintaining low resistance for long periods and improving productivity by eliminating the need for separate anticorrosion layers, while maintaining electrical connections and preventing corrosion under harsh conditions.
Implementation Method 1
a photoresist film 32 is formed and patterned on the ITO film 31
Implementation Method 2
the metal film 34 and the ITO film 31 are simultaneously removed by etching using ferric chloride solution
Data Source
Figure 9(a)~10
Figure 11~13(a)
Figure 13(b)~13(c)
AI summary
Provided is a method of manufacturing a narrow frame touch input sheet that is suitable for a capacitance type touch sensor having a narrow frame and a double-layer transparent conductive film pattern, and has a very good anticorrosion property. The method includes using an electrical conductivity sheet obtained by sequentially forming transparent conductive films, light blocking conductive films, and first resist layers on both sides of a transparent base sheet, exposing and developing the first resist layers on both sides simultaneously, etching the transparent conductive films and the light blocking conductive films simultaneously, removing the first resist layers, laminating second resist layers with anticorrosion agent added and patterned on the revealed light blocking conductive films, etching only the light blocking conductive films in center windows and terminal portions so that the transparent conductive films are revealed, and further performing side etching of revealed end faces of the light blocking conductive films at boundaries with the center windows and with the terminal portions so that the second resist layers have a visor structure. Finally, the second resist layers of the visor structure are softened by heat treatment so as to cover the revealed end faces of the remaining light blocking conductive films, and in the same state, the second resist layers are not removed but are left as an anticorrosion layer.