Conforming Capacitive Touch Sensor Assembly for Curved Surfaces

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Solution Overview

Problem

Conventional capacitive touch sensor assemblies face challenges when integrated into non-flat surfaces, such as those found in wearable devices, due to variations in electrode distance from the surface, leading to inconsistent touch sensitivity and potential wrinkling or bubbling of flexible substrates, which can impair sensor functionality.

Innovation Solution

A flexible capacitive touch sensor assembly with strategically placed cutouts on a flexible substrate, designed to conform to non-flat surfaces while minimizing wrinkling and maintaining sensor accuracy, combined with an optical sensor method for precise alignment and orientation of the housing surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a flexible substrate is used to conform to non-flat surfaces, then adaptability to curved surfaces is improved, but wrinkling and bubbling occur that impair sensor functionality

Engineering Contradiction:

Improveadaptability to non-flat surfacesVSAvoidsensor functionality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The flexible substrate is segmented by introducing a pattern of cutouts that divide the substrate into multiple regions. This segmentation allows each region to independently conform to the non-flat surface without causing wrinkling or bubbling, thereby maintaining sensor functionality while adapting to curved surfaces.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cutouts are strategically positioned in specific local regions of the flexible substrate where wrinkling is most likely to occur. This local modification approach maintains the integrity of sensor regions while allowing the substrate to conform to non-flat surfaces without compromising overall sensor functionality.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If the flexible substrate is made more compliant to reduce wrinkling, then ease of conforming to non-flat surfaces is improved, but touch sensitivity consistency deteriorates

Engineering Contradiction:

Improveease of conforming to surfaceVSAvoidtouch sensitivity consistency

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

By segmenting the substrate through cutouts, the patent enables the substrate to conform to non-flat surfaces with appropriate compliance while maintaining consistent electrode positioning. The segmentation allows controlled flexibility without compromising the precision needed for consistent touch sensitivity.

Inventive Principle:

Principle #1Segmentation

3Shape

If cutouts are added to the flexible substrate to reduce wrinkling, then surface conformability is improved, but device complexity increases

Engineering Contradiction:

Improvesurface conformabilityVSAvoidsubstrate structure

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The substrate is segmented with cutouts that are integrated into the manufacturing process rather than added as separate components. This segmentation approach improves surface conformability while minimizing the increase in device complexity by using a single-substrate solution with geometric modifications.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses a flexible substrate with cutouts that maintains the thin-film nature of the original substrate. This approach improves surface conformability without significantly increasing device complexity, as the solution remains within the flexible substrate paradigm rather than introducing rigid or multi-component structures.

Inventive Principle:

Principle #30Flexible shells and thin films

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 consistent touch sensitivity across non-flat surfaces by reducing wrinkling and bubbling, and enables reliable and accurate detection of touch inputs, enhancing the functionality and user experience of capacitive touch sensors in devices like headphones.

Implementation Method 1

A flexible capacitive touch sensor assembly with strategically placed cutouts on a flexible substrate, designed to conform to non-flat surfaces while minimizing wrinkling

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

an optical sensor method for precise alignment and orientation of the housing surface

Methodology Applied

Scientific EffectOptical detection:

Data Source

PatentUS12118268B2Playback device with conforming capacitive touch sensor assembly

Publication Date: 2024.10.15 SONOS INC

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.