Integrated PCB Coil and Influencing Element for Inductive Sensor

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Solution Overview

Problem

Inductive proximity sensors and switches face challenges in achieving cost-effectiveness while maintaining detection accuracy and sensitivity for approaching metallic objects, as existing designs often require separate attachment of influencing elements and are not symmetrical, leading to increased manufacturing costs and potential disturbances in sensor properties.

Innovation Solution

The integration of a printed circuit coil with a metallic influencing element on a circuit board, arranged opposite to the front end, allows for a symmetrical and cost-effective design by eliminating symmetry disturbances and minimizing the area of the influencing element, enabling efficient electrical connection to control electronics without separate attachment, thus forming a unified sensor housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a separate metallic influencing element is attached to the circuit board, then the sensor can detect metallic objects, but the manufacturing cost increases and the symmetry is disturbed

Engineering Contradiction:
Improvedetection accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent combines the metallic influencing element directly into the circuit board structure, merging two previously separate components (circuit board and influencing element) into a single integrated unit. This eliminates the need for separate attachment processes, reduces manufacturing steps, and maintains detection functionality while improving ease of manufacture.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The circuit board is designed to serve multiple functions: it provides electrical connections for the sensor circuitry and simultaneously acts as the metallic influencing element for detection. This multi-functionality eliminates the need for a separate influencing element component, reducing part count and manufacturing complexity while maintaining detection accuracy.

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

2Measurement precision

If a separate metallic influencing element is attached to the circuit board, then the sensor can detect metallic objects, but the device complexity increases due to separate attachment requirements

Engineering Contradiction:
Improvedetection accuracyVSAvoidstructural complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the metallic influencing element with the circuit board into a single integrated structure, eliminating the need for separate attachment mechanisms, mounting holes, fasteners, or adhesive processes. This integration simplifies the overall device structure and reduces assembly complexity while maintaining the necessary detection functionality.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the influencing element area is minimized, then the sensor properties are optimized, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvesensor propertiesVSAvoidpositioning precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

By integrating the metallic influencing element directly into the circuit board during the board manufacturing process, the patent eliminates the need for separate positioning and attachment operations. The influencing element's position and dimensions are determined during circuit board fabrication using standard PCB manufacturing processes, which provide consistent precision without requiring additional high-precision assembly steps.

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

This approach results in a more cost-effective production method while maintaining essential sensor properties, enabling non-contact detection of metallic objects with improved accuracy and sensitivity, suitable for electrical and electronic switching, measuring, and control circuits.

Implementation Method 1

An alternating current of about 200 kHz flows in the oscillating circuit coil. The alternating current builds up an alternating electromagnetic field in the vicinity of the oscillating circuit coil.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

If a so-called electrically conductive object ('target'), usually a metal flag, is placed in this alternating field, eddy currents are induced in it according to the law of induction. As a result, electrical energy is withdrawn from the circuit of the oscillator

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Data Source

PatentEP3183817B1Inductive proximity sensor of integrated design
Publication Date: 2021.05.05 BALLUFF
  • EP3183817B1 patent drawingFigure 1
  • EP3183817B1 patent drawingFigure 2
  • EP3183817B1 patent drawingFigure 3

AI summary

The invention relates to a front end for an inductive proximity sensor, comprising a coil for detecting an approaching metal object and comprising a circuit board (105), wherein the coil is designed as a circuit board coil disposed in the circuit board (105), wherein a metal influencing element (115) which is disposed in or on the circuit board (105) and has an opening to receive at least one electrical connecting element, wherein a through connection of the circuit board (105) to an electrical connection plane (120), which serves for electrical connection of the circuit board (105) to a control electronics of the proximity sensor, is made by means of the at least one electrical connecting element.