Touch Sensor Non-Linear Electrode Gap for Pressure Sensitivity
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Solution Overview
Problem
Existing touch sensors with electrode wires arranged parallel to the central axis of a tubular member face sensitivity issues when external pressure is applied in specific directions, particularly due to linear gaps between electrodes, which can lead to decreased sensitivity and increased manufacturing burdens.
Innovation Solution
A touch sensor design featuring a hollow tubular member with first and second electrode wires that extend parallel to the central axis, where the gap between them is non-linear in cross-section, allowing for elastic deformation and contact upon external pressure, and a manufacturing method using extrusion molding to integrate conductive elastic bodies and interposition members, eliminating the need for a spacer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrode wires are arranged spirally on the inner peripheral surface of the hollow tubular elastic body, then the touch sensor can sense external pressure, but the friction resistance between the spacer and electrode wires becomes large making spacer extraction difficult
Solution Approach 1:
The patent inverts the conventional arrangement by extending electrode wires parallel to the central axis instead of spiraling them, and positions them on the outer peripheral surface rather than the inner peripheral surface. This inversion reduces friction resistance during spacer extraction while maintaining pressure sensing capability through elastic deformation of the tubular body.
Solution Approach 2:
The patent employs a hollow tubular elastic body with curved geometry where electrode wires are arranged parallel to the central axis. The curved tubular structure allows elastic deformation under external pressure, enabling the wires to contact while maintaining ease of manufacturing through reduced friction with the spacer.
2Ease of manufacture
If electrode wires are arranged linearly parallel to the central axis of the tubular member, then the friction resistance during spacer extraction is reduced, but the sensitivity to pressure in specific directions decreases
Solution Approach 1:
The patent applies local quality by creating a non-linear gap shape between electrode wires at specific locations along the tubular member. This localized non-linear configuration ensures that pressure applied in any direction causes the wires to contact, maintaining high sensitivity while preserving the linear parallel arrangement for easy manufacturing.
Solution Approach 2:
The patent changes the geometric parameter of the gap between electrode wires from linear to non-linear shape. This parameter change ensures that pressure sensitivity is maintained in all directions while keeping the electrode wires arranged parallel to the central axis for ease of manufacturing.
3Manufacturing precision
If a spacer is used to maintain the space between electrode wires during manufacturing, then the electrode wires can be positioned accurately, but an additional extraction process is required increasing manufacturing complexity
Solution Approach 1:
The patent extracts and eliminates the spacer component from the manufacturing process. By arranging electrode wires on the outer peripheral surface and using a non-linear gap configuration, the wires can be positioned accurately without requiring a spacer, thereby simplifying the manufacturing process and eliminating the extraction step.
Solution Approach 2:
The patent merges the electrode wire arrangement with the outer peripheral surface of the tubular member. This integration allows the wires to be positioned accurately through the non-linear gap configuration without requiring a separate spacer component, combining multiple functions into a single structure.
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 design enhances sensitivity by ensuring contact across various pressure directions without significant sensitivity loss and reduces manufacturing costs by eliminating the spacer extraction process.
Implementation Method 1
the first electrode wire and the second electrode wire contact with each other by elastic deformation when receiving an external pressure to the tubular member
Data Source
AI summary
A touch sensor includes a hollow tubular member that is elastic and insulative; and a first electrode wire and a second electrode wire held in the tubular member while being separated from each other. The first electrode wire and the second electrode wire contact with each other by elastic deformation when receiving an external pressure to the tubular member. The first electrode wire and the second electrode wire extend parallel to a central axis of the tubular member. A shape of a gap between the first electrode wire and the second electrode wire in a cross section orthogonal to the central axis of the tubular member is non-linear.