Curved Electrode Patterns for Cylindrical Touch Sensors
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Solution Overview
Problem
Conventional capacitive touch sensors are limited in their ability to effectively sense touch positions on three-dimensional surfaces, particularly curved surfaces, as they are designed for two-dimensional planes, leading to issues with interpreting continuous touch movements and recognizing extended touches across joined edges when wrapped around cylindrical surfaces.
Innovation Solution
The development of electrode patterns that map touch movements along a circumferential line on rotationally-symmetric bodies onto a curved path within a touch-controller's coordinate system, allowing for a continuous, gap-free touch response around curved surfaces, which can be interfaced with standard touch controllers without modification, and are manufactured as flat sheets that are subsequently curved into shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional two-dimensional electrode patterns are used on three-dimensional surfaces, then manufacturing is simplified, but touch position sensing accuracy deteriorates on curved surfaces
Solution Approach 1:
The patent applies curvature by transforming flat two-dimensional electrode patterns into three-dimensional curved or cylindrical configurations. The electrodes are arranged to follow the curvature of the surface, enabling accurate touch sensing on rounded surfaces while maintaining the simplicity of standard electrode fabrication processes.
Solution Approach 2:
The invention transitions from two-dimensional planar electrode arrangements to three-dimensional curved or cylindrical electrode configurations. This dimensional change allows the electrodes to conform to the surface geometry, improving touch position sensing accuracy on three-dimensional surfaces while retaining compatibility with conventional manufacturing methods.
2Ease of manufacture
If flat electrode sheets are wrapped around cylindrical surfaces, then continuous touch tracking is disrupted at joined edges, but manufacturing remains simple
Solution Approach 1:
The patent designs electrode patterns that follow cylindrical or curved geometries, allowing the sensor to wrap around surfaces without creating discontinuities. The curved electrode arrangements ensure that touch movements are continuously tracked as they pass across what would otherwise be joined edges, eliminating gap effects while maintaining simple assembly procedures.
3Device complexity
If standard touch controllers are used with curved surfaces, then device complexity is minimized, but touch gesture recognition accuracy deteriorates
Solution Approach 1:
The patent employs curved or cylindrical electrode arrangements that work seamlessly with standard touch controllers. The geometric transformation of the electrode pattern compensates for the surface curvature, allowing conventional controllers to accurately recognize gestures on three-dimensional surfaces without requiring complex reconfiguration or specialized processing algorithms.
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 solution enables continuous tracking of touch movements around a complete circumference without edge effects, allowing for accurate reporting of touch positions and gestures on three-dimensional surfaces, such as cylindrical surfaces, using conventional touch controllers.
Implementation Method 1
a controller chip connected to the electrodes and operable to measure changes in the electrical capacitance of each of the electrodes or the mutual-capacitance between combinations of the electrodes
Implementation Method 2
the touch influences the electric fields 110 that the controller chip 105 generates using the electrodes 102
Data Source
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AI summary
A touch-sensitive position sensor is disclosed. The sensor comprises an array of first electrodes and an array of second electrodes arranged to cross one another in a pattern to define a sensing surface. The sensing surface has a rectangular shape which is formed into a cylinder such that first and second opposing edges of the sensing surface are adjacent one another. A controller is coupled to respective ones of the first electrodes and the second electrodes and arranged to measure changes in an electrical parameter, e.g. capacitance or resistance, associated with the first and second electrodes caused by the presence of the object adjacent the sensing surface. The controller is further operable to determine a reported position for the object from these measurements in a coordinate system defined relative to the electrodes. At least some of the electrodes are arranged to follow paths which are non-linear within the sensing surface such that object positions along a straight line between the first and second opposing edges on the sensing surface correspond with reported positions along a closed curve in the coordinate system defined relative to the electrodes. Thus, a continuous movement around a circumference of the cylindrical sensing surface is reported as a continuous movement around a closed path in the coordinate system defined relative to the electrodes.