Conforming Capacitive Touch Assembly for Wrinkle-Free Curved Surfaces
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Solution Overview
Problem
Conventional capacitive touch sensor assemblies on non-flat surfaces, such as those found in wearable devices, face issues with inconsistent touch sensitivity due to varying electrode distances and potential wrinkling or bubbling when a flexible circuit board is conforming to these surfaces.
Innovation Solution
A flexible capacitive touch sensor assembly with strategically arranged cutouts on a flexible substrate, designed to reduce wrinkling and maintain consistent touch sensitivity, is integrated into a playback device, along with an optical sensor method for precise alignment and orientation on smooth, symmetric surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible circuit board is used to conform to non-flat surfaces, then the touch sensor can be integrated onto curved surfaces, but wrinkling or bubbling occurs causing inconsistent touch sensitivity
Solution Approach 1:
The flexible substrate is segmented into multiple regions with different properties. The first region contains the capacitive touch sensor electrodes and has different mechanical or structural characteristics than the second region, allowing the substrate to conform to non-flat surfaces while maintaining electrode stability and consistent touch sensitivity across the curved surface.
2Adaptability or versatility
If the flexible substrate is made more compliant to reduce wrinkling, then it can better conform to non-flat surfaces, but the electrode distance consistency deteriorates
Solution Approach 1:
The substrate is divided into a first region housing the capacitive touch sensor electrodes and a second region with different mechanical properties. This segmentation allows the second region to provide compliance and reduce wrinkling when conforming to non-flat surfaces, while the first region maintains structural integrity and consistent electrode spacing for accurate touch detection.
Solution Approach 2:
Different regions of the flexible substrate are given different local qualities or properties. The first region containing the electrodes is designed with properties that maintain geometric stability and electrode distance consistency, while the second region has enhanced compliance to accommodate surface curvature and reduce wrinkling, allowing each region to optimize its specific function.
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
The solution ensures reliable and accurate touch input detection on non-flat surfaces by minimizing wrinkling and maintaining consistent touch sensitivity, while the optical sensor method facilitates precise alignment, enhancing the functionality and usability of the capacitive touch sensor assembly.
Implementation Method 1
determining, using an optical sensor, a position and an angle of rotation of a housing portion of a playback device
Data Source
AI summary
Aspects of the present disclosure relate to playback devices having a non-flat surface and comprising a flexible electronic assembly conforming to that surface. The flexible electronic assembly may include (i) a flexible substrate having a first portion and a second portion, (ii) an array of capacitive touch sensor electrodes arranged on the first portion, and (iii) a plurality of conductors that are electrically coupled to the array of capacitive touch sensor electrodes and that extend onto the second portion. The first portion may include a plurality of cutouts. Each cutout of a first subset of the plurality of cutouts may be positioned between a respective set of two or more electrodes in the array of capacitive touch sensor electrodes. Each cutout of a second subset of the plurality of cutouts may be configured to reduce a wrinkling of the first portion when conforming the first portion to the non-flat surface.