Capacitive Rotary Switch With Tactile Multi-Stage Feedback

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Solution Overview

Problem

Existing switching devices lack tactile feedback and are limited to generating a single switching signal, failing to provide multi-stage switching signals.

Innovation Solution

The operating cap is rotatably or linearly mounted within a housing, with capacitive surface sensors detecting changes in the electric field due to rotation or pivoting, generating multi-stage switching signals, and tactile feedback is provided through mechanical deformation of the actuating element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a capacitive surface sensor is used to detect touch input, then the switching device can generate switching signals, but it does not generate tactile feedback

Engineering Contradiction:
Improvetouch input detectionVSAvoidtactile feedback
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The patent combines a capacitive surface sensor with a mechanical actuating element (push button, rocker, or rotary element) into a single integrated switching device. The mechanical element provides tactile feedback through physical deformation while the capacitive sensor detects the touch input, merging the benefits of both touchless detection and tactile response in one device.

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If a simple single-stage switching signal is generated, then the device structure remains simple, but it cannot provide multi-stage switching signals for enhanced control

Engineering Contradiction:
Improveswitching signal stagesVSAvoidcontrol precision
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent segments the switching signal generation into multiple stages by detecting different positions or states of the mechanical actuating element. For example, a rotary element can detect different rotational positions, or a push button can detect different press depths, each generating distinct switching signals. This segmentation allows the device to provide multi-stage control while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #1Segmentation

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 enables the generation of differentiated multi-stage switching signals and provides tactile feedback, enhancing user interaction and control precision.

Implementation Method 1

the capacitive surface sensor detects changes in the electric field caused by the cap's rotation and/or pivoting, a multi-stage and differentiated switching signal is generated. Due to the capacitive coupling between the operating cap and the surface sensor

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Implementation Method 2

the actuating element, located between the operating cap and the capacitive surface sensor, to be elastically deformed

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3706315B1Switching device for converting a manual and/or mechanical feed motion into a switching signal
Publication Date: 2026.01.14 RAFI GMBH & CO KG
  • EP3706315B1 patent drawingFigure 1a~1c
  • EP3706315B1 patent drawingFigure 2a~2b
  • EP3706315B1 patent drawingFigure 3a~3c

AI summary

In a switching device (1) for converting a manual and/or mechanical feed movement into at least one switching signal (10) by which an electrical device is controlled, consisting of: - a switching housing (3) in which a receiving opening (4) is incorporated, - an operating cap (5) which is made of an electrically conductive material and is movably mounted on or in the receiving opening (4) of the switching housing (5) along a feed direction (8), - a capacitive area sensor (6) which generates a spatially acting electric field for capacitive evaluation and which is arranged on the side of the operating cap (5) opposite the feed direction (8) in or outside the switching housing (3) and which generates a switching signal (10) when the electric field changes, and - at least one actuating element (9) provided between the operating cap (5) and the capacitive area sensor (6),The electrically conductive and elastically deformable surface, which creates at least one capacitive coupling between the operating cap (5) and the capacitive surface sensor (6), is intended to generate and evaluate a multi-stage switching signal in the form of a capacitive rotary, sliding, or rocker function. This is achieved by mounting the operating cap (5) rotatably in or on the switching housing (3) in the manner of a rotary switch, a toggle switch, and/or a rocker, and by allowing the capacitive surface sensor (6) to detect a change in the electric field through the rotation and/or pivoting of the operating cap (5).