Large-Area Touch Sensor Segmented Electrode Manufacturing
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Solution Overview
Problem
The challenge in manufacturing large-area touch sensors is the increased complexity and defects such as tearing and wrinkling of base films, along with the need for modified process equipment, which hinders efficient production and reliability.
Innovation Solution
A touch sensor design featuring alternately arranged sensing electrode rows with periodically bent traces and floating traces, connected through a stitching method using a photo-mask, allowing for efficient patterning and alignment without requiring changes to existing exposure/patterning equipment, and incorporating sensing column electrodes and bridge electrodes for enhanced connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the sensing electrodes are simultaneously formed or transferred in a large-scaled area, then the touch sensor can be manufactured, but defects such as tearing and wrinkling of the base film occur
Solution Approach 1:
The touch sensor is divided into multiple blocks, each containing a subset of sensing electrodes. These blocks are manufactured separately using existing exposure apparatus, then sequentially transferred and stitched together on the substrate. This segmentation allows the use of current equipment without modification while avoiding the film defects that would occur with simultaneous large-area formation.
Solution Approach 2:
The sensing electrodes in each block are pre-formed on separate regions before being transferred to the final substrate. This preliminary formation allows each block to be manufactured independently with proper film handling, preventing tearing and wrinkling, and ensures high reliability before the final assembly step.
2Area of stationary object
If the area of the touch sensor is increased to match large-scaled display screens, then more sensing electrodes are included, but the exposure apparatus and exposure mask require modification
Solution Approach 1:
The large-area touch sensor is segmented into multiple smaller blocks that can be manufactured using existing exposure apparatus. Each block contains a manageable number of sensing electrodes that fit within the capabilities of current equipment, eliminating the need to modify exposure apparatus or masks while still achieving large overall sensor area.
Solution Approach 2:
Instead of increasing the area of a single exposure mask, the solution transitions to a multi-block approach where multiple smaller masks are used. The stitching process then adds a temporal and procedural dimension to the manufacturing process, allowing large-area coverage through sequential operations rather than requiring a single large mask.
3Area of stationary object
If the sensing electrodes are formed in a large-scaled area, then the touch sensor covers the entire display screen, but the base film experiences tearing and wrinkling
Solution Approach 1:
The large-area electrode formation is segmented into multiple smaller blocks, each transferred separately to the substrate. This segmentation ensures that the base film is handled in manageable portions during transfer, preventing tearing and wrinkling while still achieving complete coverage of the display screen area.
Solution Approach 2:
Each block of sensing electrodes is pre-formed and stabilized on its designated region before transfer. This preliminary action ensures proper film adhesion and positioning, preventing wrinkling and tearing during the transfer process, and maintains manufacturing precision even as the overall coverage area increases.
Data Source
AI summary
A touch sensor according to an embodiment of the present invention includes a substrate layer, first sensing electrode rows and second sensing electrode rows alternately arranged on the substrate layer, first traces extending from left ends of the first sensing electrode rows, the first traces including periodically arranged bent portions, second traces extending from right ends of the second sensing electrode rows, the second traces including periodically arranged bent portions, a first floating trace adjacent to an outermost first trace of the first traces, and a second floating trace adjacent to an outermost second trace of the second traces.