Capacitive Sensor Electrode Positioning for Haptic Feedback

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Solution Overview

Problem

Capacitive proximity sensors in existing operating devices often affect the haptic feedback of depressible buttons and limit uniform backlighting due to their integration within the button body, impacting user experience.

Innovation Solution

The capacitive proximity sensor electrode is arranged outside the guide element and button body, designed as a helical spring between the carrier plate and front panel, ensuring mechanical independence and maintaining haptic integrity while providing reliable object detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the capacitive proximity sensor electrode is integrated within the button body, then the sensor can detect approaching objects reliably, but the haptic feedback of the button is affected and backlighting uniformity is limited

Engineering Contradiction:
Improveobject detection reliabilityVSAvoidhaptic feedback quality
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The electrode is extracted from the button body and relocated to the guide element structure. Specifically, the electrode is arranged on the inner side of the guide element wall, separating it from the button body's mechanical structure. This extraction eliminates the interference of the electrode with button haptics while preserving proximity detection functionality through capacitive sensing of approaching objects.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The guide element is given multiple functions: it provides mechanical guidance for the button body during depression, structural support for the electrode arrangement, and serves as the mounting structure for the capacitive proximity sensor. This multi-functionality eliminates the need for separate components and maintains compact design while resolving the haptic interference issue.

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

2Measurement precision

If the capacitive proximity sensor electrode is integrated within the button body, then the sensor can detect approaching objects, but uniform backlighting of the button is restricted

Engineering Contradiction:
Improveobject detection capabilityVSAvoidbacklighting uniformity
Core Design Contradiction:
Measurement precisionVSIllumination intensity

Solution Approach 1:

The electrode is extracted from the button body and positioned on the guide element structure. This relocation removes the physical obstruction that the electrode would create within the button body, allowing light to pass through the button uniformly from the backlight source without being blocked or scattered by sensor components.

Inventive Principle:
Principle #2Taking out (Extraction)

3Device complexity

If the electrode is arranged inside the guide element receiving space, then the sensor structure is compact, but the button haptics are mechanically affected

Engineering Contradiction:
Improvesensor structure compactnessVSAvoidbutton haptic properties
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The electrode arrangement moves from a two-dimensional plane within the button body to a three-dimensional position on the guide element wall surface. This dimensional change allows the electrode to be positioned in the available space of the guide element structure without interfering with the button's mechanical depression path and haptic characteristics.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 arrangement preserves the natural haptic properties of the button and allows for uniform illumination, enhancing user interaction without mechanical interference from the sensor components.

Implementation Method 1

a capacitive proximity sensor with at least one electrode (34) for detecting an object (48) approaching a front wall (27) of the button body (26)

Methodology Applied
Scientific EffectCapacitive proximity sensing: Capacitance

Implementation Method 2

The electrode is designed as a helical spring, ie as a spring element, by means of which the electrode is arranged under tension between the carrier plate and a front panel of the operating device

Methodology Applied
Scientific EffectSpring preload: Spring

Data Source

PatentEP2700166B1Operating device, in particular for a vehicle component
Publication Date: 2019.11.06 BEHRN-HELLA THERMOCONTROL GMBH
  • EP2700166B1 patent drawingFigure 1
  • EP2700166B1 patent drawingFigure 2

AI summary

The operating device (10), in particular for a vehicle component or generally for a human/machine interface, is provided with at least one pushbutton (28), which has a depressible pushbutton element (26). In addition, the operating device (10) has a guide element (18), which defines an accommodating area (24) in which the pushbutton element (26) is at least partially accommodated and in which the pushbutton element (26) is guided, and a capacitive proximity sensor (36) with an electrode (34) for detecting an object approaching the pushbutton element (26), in particular a hand or a finger of a hand. The electrode (34) is arranged outside the accommodating area (24) of the guide element (18).