Multi-Electrode Capacitive Sensing for Accurate Long-Range Detection

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Solution Overview

Problem

Capacitive sensors face challenges in reliably detecting objects at a distance, especially when objects are far away and decoupled from the environmental potential, leading to issues with false positives and reduced detection accuracy due to varying object sizes and coupling to the environment.

Innovation Solution

A capacitive sensor system comprising multiple sensors with spatial diversity, where measurement signals from multiple electrodes are evaluated to determine object position and shape, allowing for long-range detection independent of object properties and environmental coupling, using a processor to combine signals and estimate object location accurately.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If a single capacitive sensor device is used for long-range detection, then the detection range is extended, but the detection accuracy and reliability deteriorate due to false positives and environmental coupling effects

Engineering Contradiction:
Improvedetection rangeVSAvoiddetection accuracy
Core Design Contradiction:
Length of stationary objectVSMeasurement precision

Solution Approach 1:

The patent divides the detection task into multiple independent sensor devices (at least three) arranged in spatial distribution. Each sensor device independently measures objects in its own field region, and the evaluation device combines these measurements to achieve accurate long-range detection while eliminating false positives that would occur with a single sensor.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the sensitivity of a capacitive sensor is increased to detect far-range objects, then the detection capability is improved, but the false positive rate increases due to environmental interference

Engineering Contradiction:
Improvedetection capabilityVSAvoidfalse positives
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The evaluation device receives measurement signals from multiple sensor devices and processes them to determine object position and shape. By comparing and cross-validating measurements from multiple sensors, the system provides feedback that eliminates false positives while maintaining high sensitivity for detecting actual objects at a distance.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If multiple sensor devices are used to improve detection accuracy, then the measurement precision is improved, but the device complexity increases

Engineering Contradiction:
Improveobject position detection accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple sensor devices into a unified sensor arrangement with a central evaluation device that processes all measurement signals. This merging approach achieves high detection accuracy through spatial diversity while managing complexity by using a coordinated system architecture where each sensor device follows the same structure and the evaluation device applies consistent processing algorithms.

Inventive Principle:
Principle #5Merging (Combining)

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 system enables reliable detection of objects at a distance, reducing false positives and improving robustness by accounting for object size and coupling, while maximizing sensitivity and detection range, thus enhancing safety and accuracy in proximity detection.

Implementation Method 1

Capacitive sensors are used in a variety of ways to detect objects and in particular dielectric and conductive objects in the vicinity of an electric field. The capacitive operating principle is particularly well suited for recognizing persons and living beings.

Methodology Applied
Scientific EffectCapacitive sensing: Capacitance

Implementation Method 2

a first capacitive sensor device which has a first electrode and a second electrode between which a first electric field can be built up

Methodology Applied
Scientific EffectElectric field: Electric Field

Data Source

PatentEP3758232A1Sensor device, in particular for detecting objects
Publication Date: 2020.12.30 ROBERT BOSCH GMBH
  • EP3758232A1 patent drawingFigure 1~2
  • EP3758232A1 patent drawingFigure 3~4
  • EP3758232A1 patent drawingFigure 5~6

AI summary

A sensor arrangement (10) for detecting objects (50) with a first capacitive sensor device (2) which has a first electrode (22) and a second electrode (24) between which a first electric field (E1) can be established and with a second capacitive sensor device (4) which has a first electrode (42) and a second electrode (44) between which a second electric field (E2) can be established, characterized in that the sensor arrangement (10) has a third capacitive sensor device (6) which has a first electrode (62) and a second electrode (64) between which a third electric field (E3) can be established.