Capacitive Sensor Module Wire Electrode Alignment

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Solution Overview

Problem

The manufacture and maintenance of capacitive sensor arrangements for detecting object penetration in motor vehicles are complicated and expensive due to alignment and fixation challenges of electrodes.

Innovation Solution

A capacitive sensor module with a sensor electrode and auxiliary electrodes formed from cables or wires, housed in a plastic carrier with recesses for precise alignment and stable fixation, allowing for easy assembly and repair, and featuring a shielding electrode configuration for enhanced sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If electrodes are aligned and fixed in traditional capacitive sensor arrangements, then detection sensitivity is achieved, but manufacture and maintenance become complicated and expensive

Engineering Contradiction:
Improvedetection sensitivityVSAvoidmanufacture complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent uses individually replaceable cable sections with integrated electrodes instead of fixed rigid electrode structures. When a cable section wears out or malfunctions, only that specific section needs to be replaced rather than the entire sensor assembly, significantly reducing maintenance costs and complexity while maintaining detection sensitivity.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The sensor arrangement is divided into separate cable sections, each with its own electrodes, that can be independently handled, aligned, and replaced. This segmentation simplifies the manufacturing process by allowing cables to be assembled from standard components rather than requiring complex custom electrode fabrication and alignment.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If electrodes are aligned and fixed in traditional capacitive sensor arrangements, then detection sensitivity is achieved, but maintenance becomes complicated and expensive

Engineering Contradiction:
Improvedetection sensitivityVSAvoidmaintenance complexity
Core Design Contradiction:
Measurement precisionVSEase of repair

Solution Approach 1:

The cable sections with integrated electrodes are designed as replaceable units. When degradation or malfunction occurs, the entire cable section can be quickly swapped out without complex disassembly or realignment procedures, making maintenance simple and cost-effective while preserving the sensitive detection capability of the electrode arrangement.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The cable design allows for easy self-replacement by the end user or technician without requiring specialized tools or expertise in electrode alignment. The modular cable sections can be connected and disconnected using simple connectors, enabling straightforward maintenance operations.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If cables or wires are used to form sensor electrodes, then ease of assembly and repair is improved, but alignment precision must be maintained

Engineering Contradiction:
Improveassembly easeVSAvoidalignment precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent introduces plastic carriers with precisely formed recesses as intermediaries between the flexible cables and the final electrode positions. These recesses mechanically guide and position the cables during assembly, ensuring accurate alignment and spacing of the electrodes while allowing the cables themselves to remain easy to handle and install.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The use of flexible cables with integrated electrodes allows for easy assembly and connection, while the plastic carrier provides the rigid structural framework that ensures precise alignment. This combination leverages the advantages of both flexible and rigid components to achieve both ease of assembly and manufacturing precision.

Inventive Principle:
Principle #30Flexible shells and thin films

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 a cost-effective, robust, and sensitive capacitive proximity sensor with reproducible alignment and easy maintenance, improving the detection range and reducing environmental interference.

Implementation Method 1

a capacitive sensor arrangement with a sensor electrode, with a control and evaluation circuit coupled to the sensor electrode, which detects a change in the capacitance of the sensor electrode with respect to ground by periodically measuring the sensor electrode at a predetermined frequency

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

the field propagating from the sensor electrode extends more strongly into the space in front of the sensor electrode (detection area)

Methodology Applied
Scientific EffectElectric Field: Electric Field

Implementation Method 3

a shielding electrode, which is arranged between the sensor electrode and the ground background electrode and which is coupled to the sensor electrode via a control and evaluation circuit in such a way that it Potential tracking the potential of the sensor electrode

Methodology Applied
Scientific EffectPotential tracking:

Implementation Method 4

the strong electric field is created between the shielding electrode and the background electrode

Methodology Applied
Scientific EffectElectric Field: Electric Field

Data Source

PatentEP2284999B1Sensor module
Publication Date: 2014.05.14 HUF HÜLSBECK & FÜRST GMBH & CO KG
  • EP2284999B1 patent drawingFigure 1~2
  • EP2284999B1 patent drawingFigure 3~4
  • EP2284999B1 patent drawingFigure 5A~5B

AI summary

A capacitive sensor module with a sensor electrode, which detects the entry of an object into a space in front of the sensor electrode, wherein the sensor electrode is formed from a wire. Parallel to the sensor electrode, auxiliary electrodes extend within a plastic carrier, which has recesses for receiving the sensor electrodes and auxiliary electrodes and partially surrounds them along their circumference. The sensor electrodes can be pressed into the plastic carrier by overcoming an elastic deformation force and are held in their recesses by the elastic return to their original shape.