Trace Transfer Techniques for Touch Sensor Panels
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Solution Overview
Problem
Existing touch sensitive devices face challenges in efficiently routing conductive traces from one side of a substrate to another, leading to excessive bending of flex circuits, which can result in reduced reliability and durability of connections between touch sensor panels and touch circuitry.
Innovation Solution
The implementation of trace transfer techniques that allow conductive traces to wrap around the edges of the substrate from one side to the other, enabling a flex circuit to be oriented perpendicular to the touch surface, thereby reducing the bending of flex circuits and enhancing the structural stability and reliability of connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive traces are routed from one side of the substrate to another using conventional methods, then the touch sensor panel can be connected to touch circuitry, but the flex circuit experiences excessive bending which reduces reliability and durability
Solution Approach 1:
The patent applies dimensionality change by routing conductive traces through the thickness dimension of the substrate rather than along the surface plane. Touch electrodes on the first side are connected to bond pads on the second side via traces that pass through the substrate thickness, enabling the flex circuit to be oriented perpendicular to the touch surface and reducing bending requirements
Solution Approach 2:
The patent inverts the conventional routing approach by having traces wrap around the edges of the substrate from one side to the other, rather than routing them across the surface. This edge-wrapping technique allows the flex circuit to connect with minimal bending, transforming the routing geometry to solve the reliability issue
2Ease of manufacture
If the flex circuit is oriented parallel to the substrate, then routing is simpler, but the bending of the flex circuit increases significantly reducing durability
Solution Approach 1:
The patent transitions the flex circuit orientation from parallel to perpendicular relative to the substrate surface. This dimensional change in orientation allows the flex circuit to connect to touch circuitry with reduced bending (90 degrees versus 180 degrees), significantly improving durability while maintaining manufacturing feasibility through automated trace transfer processes
3Area of stationary object
If conventional trace routing is used, then the touch screen occupies more border region, but the connection reliability is reduced due to excessive flex circuit bending
Solution Approach 1:
The patent inverts the routing path by having conductive traces wrap around the edges of the substrate rather than extending across the border region. This edge-wrapping approach minimizes the border region occupation while simultaneously improving connection reliability by reducing flex circuit bending, achieving both goals of the invention
Data Source
AI summary
Trace transfer techniques can be used to couple touch electrodes to touch sensing circuitry with a reduced border region around a touch sensor panel. Touch electrodes on a first side of the substrate can be routed to a bond pad region on the second side of the substrate via a trace transfer technique to enable single-sided bonding of a double-sided touch sensor panel. Trace transfer techniques can also be used to couple conductive traces on a first side of the substrate to a flex circuit oriented perpendicular to or otherwise not parallel to the first side of the substrate. Orienting the flex circuit in this way can allow the flex circuit to connect to touch circuitry with reduced bending as compared with the amount of bending of the flex circuit when oriented substantially parallel to the substrate.