Capacitive Actuating Element for Household Appliances

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Solution Overview

Problem

Conventional rotary actuating elements in electronic household appliances face limitations in accuracy and durability, particularly in capacitive systems, where mechanical wear and design constraints restrict user interaction and feedback.

Innovation Solution

A capacitive actuating element with electrically non-conductive substrates, multiple spaced conductive measuring electrodes, and a conductive operating element, allowing for precise capacitance changes detection without contact, enabling enhanced accuracy and user feedback through varying distances and deformability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional mechanical rotary toggles are used, then the structure is simple and easy to manufacture, but mechanical wear occurs and accuracy is limited

Engineering Contradiction:
ImprovedurabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the conventional mechanical rotary toggle system with a capacitive sensing system. The operating element interacts with measuring electrodes through capacitive coupling rather than direct mechanical contact, eliminating mechanical wear while detecting rotational position and push-button actions through capacitance changes.

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

Solution Approach 2:

The patent introduces a dielectric layer as an intermediary between the operating element and the measuring electrodes. This dielectric enables capacitive coupling while physically separating the moving operating element from the stationary electrodes, allowing contactless detection while maintaining a relatively simple structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If capacitive sensing is used, then mechanical wear is reduced, but measurement accuracy and user feedback are limited

Engineering Contradiction:
Improveactuation detection accuracyVSAvoiduser interaction quality
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent divides the sensing system into multiple independent measuring electrodes arranged around the operating element. Each electrode can independently detect capacitance changes, enabling precise determination of rotational position and differentiation between rotational and push-button actions through pattern recognition of the capacitance signals.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs a deformable operating element that can dynamically change its shape and position in response to user input. The element can be rotated, pushed, or pressed, creating dynamic capacitance variations that provide rich feedback information for accurate detection of different user actions.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the operating element is made electrically conductive, then capacitive coupling is enhanced, but design flexibility is reduced

Engineering Contradiction:
Improvecapacitive coupling strengthVSAvoiddesign flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent employs composite material construction for the operating element, combining electrically conductive materials with deformable or flexible materials. This allows the element to maintain good electrical coupling with the measuring electrodes while simultaneously providing design flexibility for different shapes, deformation characteristics, and user interaction modes.

Inventive Principle:
Principle #40Composite materials

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 provides low-wear, high-accuracy actuation with improved user interaction and design flexibility, enabling precise movement detection and expanded input options like rotary and push-button functions, while reducing the need for additional components.

Implementation Method 1

the measuring electrodes on the one hand and the sensor section of the operating element on the other hand form the electrodes of a capacitance with a dielectric (formed by the spacing) between them

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

a dielectric (formed by the spacing) between them

Methodology Applied
Scientific EffectDielectric: Dielectric

Data Source

PatentEP2997659B1Actuating element
Publication Date: 2020.07.29 DIEHL AKO STIFTUNG & CO KG
  • EP2997659B1 patent drawingFigure 1
  • EP2997659B1 patent drawingFigure 2~3

AI summary

The invention relates to an actuating element (12) for an electronic domestic appliance having an electrically non-conductive carrier (18) which defines at least one preferably substantially cylindrical detection section (19); a plurality of electrically conductive measuring electrodes (20), which are arranged spaced apart from one another along the detection section (19) of the carrier; and a preferably substantially annular operating element (26), which is arranged at first predefined distance (a) from the measuring electrodes (20) and can be moved relative to the latter. The operating element (26) additionally has at least one sensor section (28), which is configured to be at least partly electrically conductive and is arranged at a second predefined distance (b) from the measuring electrodes (20) which is different from the first predefined distance (a), such that a movement of the sensor section (28) and therefore of the operating element (26) relative to the arrangement of the measuring electrodes (20) can be detected.