Multilayer Capacitive Sensor Electrode Switching for Vehicle Door Detection

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Solution Overview

Problem

Modern vehicles require complex and flexible operating options for capacitive proximity detection, which existing sensor arrangements struggle to provide due to rigid functionality and limited adaptability in detecting different user interactions.

Innovation Solution

A multilayer circuit board with multiple metallization levels, where electrode areas can temporarily function as sensor, ground, or shield electrodes, allowing for time-division multiplexed control and synchronization with an evaluation device to adapt detection schemes based on user interactions and vehicle conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple sensor devices are used to detect different user interactions, then detection capability is improved, but device complexity increases

Engineering Contradiction:
Improvedetection capabilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies multi-functionality by enabling electrode areas to perform multiple roles (sensor electrode, ground electrode, shield electrode) through time-division multiplexing. The control device dynamically assigns different functions to the same physical electrodes at different times, allowing a single sensor device to detect multiple types of user interactions (approach, grip, release) that would traditionally require separate devices.

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

Solution Approach 2:

The patent implements dynamics through time-division multiplexing where the functional configuration of electrodes changes dynamically over time. The control device switches between different operational modes (first detection scheme with sensor electrode facing first direction, second detection scheme with sensor electrode facing second direction) based on detection needs, making the system adaptable rather than static.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If electrode areas are assigned fixed functions, then device simplicity is maintained, but adaptability to different detection schemes is limited

Engineering Contradiction:
Improvedevice simplicityVSAvoidadaptability to detection schemes
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies periodic action through time-division multiplexing where electrode areas are periodically switched between different functional assignments. The control device cycles through different detection schemes, assigning sensor, ground, and shield electrode roles to different physical electrodes in alternating time periods, enabling the system to maintain simplicity while achieving adaptability through rhythmic reconfiguration.

Inventive Principle:
Principle #19Periodic action

3Device complexity

If a single sensor electrode detects approaches from all directions, then device simplicity is maintained, but measurement precision for directional detection is reduced

Engineering Contradiction:
Improvedevice simplicityVSAvoiddirectional detection precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies segmentation by dividing the detection task into directional segments. Instead of using one omnidirectional sensor, the system segments detection into different spatial directions (first direction and second direction) and activates appropriate electrode areas based on the direction from which approach is detected, thereby maintaining simplicity while improving directional measurement precision.

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

Enables flexible and efficient detection of user interactions, such as opening and closing a vehicle door, by dynamically reconfiguring electrode functions without the need for multiple sensor devices, enhancing sensing capabilities and adaptability.

Implementation Method 1

A control device is coupled to the sensor electrode in order to apply an electrical voltage to the sensor electrode with respect to a reference potential

Methodology Applied
Scientific EffectElectrical voltage application: Electric Field

Implementation Method 2

An evaluation device detects changes in capacitance on the sensor electrode in order to detect the approach of a user to the sensor electrode

Methodology Applied
Scientific EffectCapacitance change detection: Capacitance

Implementation Method 3

Capacitive proximity sensing systems are known in the art. A capacitance develops between the sensor electrode, which is brought to a predetermined potential, and a reference electrode

Methodology Applied
Scientific EffectCapacitive proximity sensing: Electrostatic Induction

Data Source

PatentEP3149855B1Sensor device for a motor vehicle
Publication Date: 2020.12.16 HUF HÜLSBECK & FÜRST GMBH & CO KG
  • EP3149855B1 patent drawingFigure 1~3

AI summary

The invention relates to a sensor device for a motor vehicle, comprising a multi-layer circuit board (2), on which a plurality of metallization levels are formed. A capacitive sensor electrode is formed on one of the metallization levels for detection by means of capacitive proximity sensing. A control device (3) controls the sensor electrode as a capacitive sensor electrode in order to detect approaches of a user toward the sensor electrode by means of an evaluating device. At least one planar electrode region (11, 12, 13, 14, 15, 16, 17, 18, 19) is formed on each of a plurality of the metallization levels, wherein each of the electrode regions is coupled to the control device (3). At least two of the electrode regions on different metallization levels are controlled and evaluated as sensor electrodes in alternation in time, and at least two of the electrode regions on different metallization levels are controlled and evaluated as a ground in alternation in time.