Roll-to-Roll Touch Sensor Manufacturing via Via Holes
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Solution Overview
Problem
The manufacturing of capacitive touch panels with double-layered touch sensors is costly and prone to thickness issues, and the single-layered touch panels face limitations in continuous processing and humidity/temperature-induced cracks at adhering parts.
Innovation Solution
A touch sensing apparatus is manufactured using a roll-to-roll process with electrode patterns and interconnection patterns formed on separate substrates, connected via holes, and assembled to reduce costs and tact time, with a transparent window and adhesive layers to enhance durability and visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a double-layered touch sensor structure is used, then sensing accuracy is improved, but manufacturing cost increases and thickness increases
Solution Approach 1:
The patent combines drive and sense electrode traces into a single layer, eliminating the need for separate drive and sense electrode layers. This merging approach maintains sensing functionality while reducing manufacturing complexity and cost, directly addressing the contradiction between sensing accuracy and manufacturing ease.
Solution Approach 2:
The single-layer electrode structure serves multiple functions: it acts as both drive and sense electrodes, and integrates with the FPCB through via holes. This multi-functional design eliminates the need for separate dedicated drive and sense layers, reducing manufacturing steps while maintaining sensing performance.
2Reliability
If separate processes are used for insulation layer formation, FPCB stacking, and wiring connection, then connection reliability is improved, but productivity decreases
Solution Approach 1:
The patent merges the insulation layer formation, electrode pattern formation, and FPCB connection processes into a single integrated manufacturing step. The insulating layer and electrode patterns are formed simultaneously on the FPCB, eliminating multiple separate processes and enabling continuous production while maintaining connection reliability.
Solution Approach 2:
The insulating layer and electrode patterns are formed in advance on the FPCB before final assembly. This preliminary formation of all necessary structures allows for continuous processing in subsequent steps, improving productivity while ensuring reliable connections are established before final product completion.
3Reliability
If FPCB and insulation layer are adhered together, then electrical connection is achieved, but cracks occur at adhering parts due to humidity and temperature changes
Solution Approach 1:
The patent changes the material parameters of the insulating layer by forming it from a resin composition with specific properties (low glass transition temperature, low coefficient of thermal expansion). These parameter changes make the insulating layer more flexible and compatible with FPCB expansion/contraction, preventing cracks while maintaining electrical connection reliability.
Solution Approach 2:
The insulating layer is formed as a composite structure combining resin materials with specific mechanical and thermal properties. This composite material approach creates an insulating layer that can accommodate humidity and temperature changes without cracking, while still providing reliable electrical insulation and connection.
Data Source
AI summary
A method for manufacturing a touch sensing apparatus includes repeatedly forming a plurality of electrode patterns on a first sub-substrate unwound from a first roller; repeatedly forming a plurality of interconnection patterns on a second sub-substrate unwound by a second roller; forming an array of touch sensing substrates by adhering the first sub-substrate to the second sub-substrate; forming a plurality of via holes through which the plurality of electrode patterns are electrically connected to the plurality of interconnection patterns; and cutting the array of touch sensing substrates into a plurality of touch sensing substrates, each touch sensing substrate including one of the electrode patterns and one of the interconnection patterns.