Seamless Force-Sensing Switch Surface for Dust-Free Controls

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Solution Overview

Problem

Existing electrical instruments face challenges in maintaining cleanliness, particularly in switch devices with movable parts that accumulate dust and impurities in slits, which complicates maintenance and reduces cost efficiency.

Innovation Solution

Integrating electric transducers, such as piezoelectric, capacitive, or strain gauges, into a single-piece body-part with a cavity that bends in response to mechanical force, eliminating slits and allowing for a uniform, easy-to-clean surface, while producing electrical signals for controlling the instrument.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If switch devices with movable parts (push buttons) are used, then the instrument can be controlled, but slits are formed where dust and impurities accumulate making cleaning difficult

Engineering Contradiction:
Improvecontrol functionalityVSAvoiddust accumulation in slits
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent merges the switch device functionality directly into the housing structure, eliminating separate movable parts and slits. The housing itself becomes the switch device, with the inner wall serving as both structural element and sensing surface, thus removing the cleaning problem while preserving control functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces traditional mechanical push buttons with a force-sensitive sensing system. Instead of mechanical movement creating slits, the housing wall itself detects force application through deformation or pressure sensing, eliminating the need for separate movable components and maintaining a seamless surface.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If a flexible sheet is added to cover switch device parts, then the surface becomes uniform and easy to clean, but the number of components increases decreasing cost efficiency

Engineering Contradiction:
ImprovecleanabilityVSAvoidnumber of components
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent combines the housing structure and switch device into a single integrated component. The housing's inner wall directly serves as the active sensing surface, eliminating the need for separate flexible sheets or covers, thus maintaining cleanability without increasing component count.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The housing structure performs multiple functions: it provides mechanical support, defines the instrument boundary, and simultaneously serves as the switch device sensing surface. This multi-functionality eliminates the need for additional components like flexible sheets while maintaining the uniform surface for easy cleaning.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Stability of the object's composition

If edges of the flexible sheet are joined to other structures, then the sheet is secured, but the edges form structures that may be difficult to keep clean

Engineering Contradiction:
Improvesheet positioningVSAvoiddust accumulation at edges
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent merges the switch device with the housing structure, eliminating separate sheets that require edging and joining. The housing's inner wall itself is the sensing surface, so no separate edges exist that could accumulate dust, while the structure remains stable and secured.

Inventive Principle:
Principle #5Merging (Combining)

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 cleanliness and cost efficiency by eliminating slit structures where dust accumulates, while effectively producing electrical signals for instrument control through mechanical force interaction.

Implementation Method 1

The electric transducers are piezoelectric transducers responsive to bending of the bottom of the cavity

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The electric transducers are capacitive transducers whose capacitance changes when the bottom of the cavity is bent

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 3

The electric transducers are strain gauges whose impedance changes when the bottom of the cavity is bent

Methodology Applied
Scientific EffectStrain gauge effect: Piezoresistive Effect

Data Source

PatentEP2803138B1A method and a switch device for producing an electrical signal in response to mechanical force
Publication Date: 2020.07.15 WALLAC
  • EP2803138B1 patent drawingFigure 1a~1b
  • EP2803138B1 patent drawingFigure 2a~2b
  • EP2803138B1 patent drawingFigure 3

AI summary

A switch device for producing one or more electrical signals in response to mechanical force comprises a body-part (101) and one or more electric transducers (102-105) connected to the body-part and arranged to produce the one or more electrical signals in response to mechanical force directed to the body-part. The body-part comprises a cavity (106), and a wall constituting the bottom of the cavity is capable of being bent by mechanical force directed to the wall from the opposite side with respect to the cavity. The one or more electric transducers are located in the cavity and arranged to produce the one or more electrical signals when the bottom of the cavity is bent. The switch device can be built, for example, into a working plane of an electrical instrument so that a plate constituting the working plane constitutes also the body-part of the switch device.