Touch Sensor Layer Interconnection Using In-Mould Lamination
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Solution Overview
Problem
Current touch sensor manufacturing processes face inefficiencies in electrical interconnection and mechanical coupling of stacked layers, which can lead to increased costs and reduced manufacturing efficiency.
Innovation Solution
The use of an in-mould lamination (IML) process to hold conductive pads in compression, facilitating electrical conductivity between layers and enhancing mechanical and electrical coupling, including the integration of a flexible printed circuit (FPC) to a substrate with touch sensor electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional manufacturing processes are used for electrical interconnection and mechanical coupling of stacked layers, then the process complexity and cost increase, but the manufacturing efficiency and reliability are reduced
Solution Approach 1:
The patent combines electrical interconnection and mechanical coupling functions into a single integrated structure. The conductive pads serve dual purposes: establishing electrical conductivity between layers while simultaneously providing mechanical coupling. This merging eliminates the need for separate connection components and processes, thereby simplifying manufacturing while maintaining or improving productivity.
Solution Approach 2:
The conductive pads are designed to perform multiple functions simultaneously: electrical conduction, mechanical coupling, and structural support. This multi-functionality reduces the total number of components required in the stacked layer assembly, streamlining the manufacturing process and improving efficiency without sacrificing reliability.
2Reliability
If conventional electrical interconnection methods are used between stacked layers, then the manufacturing cost increases, but the electrical conductivity and reliability are compromised
Solution Approach 1:
The patent merges the electrical connection function with the structural layer itself through conductive pads formed as integral parts of the stacked layers. This eliminates the need for separate wire bonds, solder joints, or connector assemblies, thereby reducing manufacturing cost while improving reliability by removing potential failure points associated with multiple interconnection interfaces.
Solution Approach 2:
The conductive pads are formed using standard semiconductor fabrication processes that replicate proven, reliable interconnection structures. By using established manufacturing techniques to create the conductive paths, the patent achieves high reliability through process maturity while controlling costs through economies of scale in standard fabrication.
3Strength
If separate mechanical coupling and electrical interconnection processes are used, then the manufacturing time and complexity increase, but the coupling strength and reliability are reduced
Solution Approach 1:
The patent combines mechanical coupling and electrical interconnection into a single simultaneous process. The conductive pads are formed and bonded to adjacent layers in one manufacturing step, rather than requiring separate mechanical assembly and electrical connection steps. This merging reduces manufacturing time while ensuring strong mechanical coupling that inherently supports the electrical connection.
Solution Approach 2:
The conductive pads are pre-formed and positioned on each layer before final assembly, ensuring proper alignment and reducing assembly time. This preliminary preparation of connection structures allows for rapid, reliable bonding during the final stacking process, minimizing manufacturing time while maximizing coupling strength.
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
This approach simplifies the manufacturing process, reduces costs, and improves the reliability of touch sensors by enabling more efficient electrical interconnection and mechanical coupling of layers, thereby enhancing the overall manufacturing efficiency and reducing die size usage.
Implementation Method 1
The IML process may facilitate holding conductive pads of various layers in compression against each other, thereby facilitating electrical conductivity between the layers
Implementation Method 2
In addition, certain embodiments may facilitate the mechanical and/or electrical coupling of various layers, including the mechanical and/or electrical coupling of a flexible printed circuit (FPC) to a substrate upon which touch sensor electrodes are formed
Data Source
AI summary
In one embodiment, a method for forming a touch sensor is provided. The method includes forming a plurality of electrodes on a first substrate. The plurality of electrodes are configured to form a plurality of capacitive nodes. Each capacitive node is configured to sense touch of an object proximate a touch sensing area of the substrate. The method further includes compressing together a plurality of conductive pads at least in part by applying a resin in liquid form to a first substrate, the resin being applied under pressure. A first one of the plurality of conductive pads had been formed on the first substrate. A second one of the plurality of conductive pads had been formed on a second substrate.