3D Proximity Switch Detection for Reliable Non-Contact HMI Input

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Solution Overview

Problem

Existing non-contact operation techniques for human-machine interfaces (HMIs) are hindered by high costs, large system requirements, environmental resistance issues, and inaccuracies in gesture recognition, making them unsuitable for harsh environments like factories and pharmaceutical production.

Innovation Solution

A programmable display device equipped with an infrared proximity sensor that detects a pointing element's position in three-dimensional space, converting non-linear detected data into effective coordinates for accurate gesture recognition and non-contact operation, reducing system complexity and improving reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If eye-tracking or image analysis is used to detect gestures, then gesture recognition accuracy is improved, but system cost and complexity increase significantly

Engineering Contradiction:
Improvegesture recognition accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential detection capability needed for gesture recognition by using a simple proximity sensor that detects movement in three directions, rather than implementing complex eye-tracking or full image analysis systems. This selective extraction achieves adequate gesture detection while dramatically reducing system complexity and cost.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs inexpensive proximity sensors instead of expensive eye-tracking cameras or image analysis systems. The simple sensor provides sufficient functionality for the application at a fraction of the cost, making the system economically viable while maintaining acceptable gesture recognition accuracy.

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

2Device complexity

If infrared proximity sensor is used for gesture detection, then system cost is reduced, but gesture recognition accuracy deteriorates

Engineering Contradiction:
Improvesystem complexityVSAvoidgesture recognition accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by focusing the proximity sensor's detection capability on specific local movements in three orthogonal directions (X, Y, Z) rather than attempting to capture full gesture complexity. This localized measurement approach achieves sufficient accuracy for HMI operation while keeping the sensor system simple and inexpensive.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the measurement parameters from complex multi-dimensional image data to simple three-directional distance measurements. By transforming the detection parameters to focus on essential movement components (dx, dy, dz), the system achieves adequate gesture recognition accuracy with minimal sensor complexity.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If simple swipe or push gestures are used, then operation ease is improved, but operational accuracy deteriorates leading to malfunctions

Engineering Contradiction:
Improveoperation easeVSAvoidoperational accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent adds dimensional precision by measuring sensor output changes in three orthogonal directions (X, Y, Z) rather than relying on simple two-dimensional swipe detection. This three-dimensional measurement approach enables accurate differentiation between intentional gestures and accidental movements, improving operational reliability while maintaining ease of use.

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

Solution Approach 2:

The patent implements feedback by continuously monitoring changes in the three-directional distance measurements and using this information to determine whether a gesture is intentional and valid. The system analyzes the pattern and magnitude of sensor output changes to confirm genuine user intent, preventing malfunctions from accidental contacts while preserving simple gesture-based operation.

Inventive Principle:
Principle #23Feedback

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 easy and reliable non-contact operation of HMIs, reducing malfunctions and costs, while maintaining accuracy and effectiveness in harsh environments.

Implementation Method 1

The distance sensor captures an image of a to-be-detected element with an infrared camera, by making use of infrared light emitted by an infrared LED and reflected at the to-be-detected element.

Methodology Applied
Scientific EffectInfrared light reflection: Reflection

Data Source

PatentEP3629135B1Action processing apparatus
Publication Date: 2024.02.28 SCHNEIDER ELECTRIC JAPAN HLDG LTD
  • EP3629135B1 patent drawingFigure 1
  • EP3629135B1 patent drawingFigure 2
  • EP3629135B1 patent drawingFigure 3

AI summary

A programmable display device (1) includes: a display panel (16) configured to display one or more switches; a proximity sensor (17) that is provided near the display panel (16) and that is configured to (i) detect a position of a pointing element in a three-dimensional space and (ii) output three detected values in three directions indicative of the position thus detected; a detecting section (331) configured to (i) identify, based on one or two first detected values of the three detected values, one switch of the one or more switches that is indicated by the pointing element, the one or two first detected values being a value(s) in one or two of the three directions, the one or two of the three directions being referred to as at least one identification direction, and (ii) detect a pressing action with respect to the one switch based on a second detected value, the second detected value being a value in another one of the three directions other than the at least one identification direction, the another one of the three directions being referred to as a pressing action detecting direction; a calculating section (332) configured to calculate an amount of movement of the pointing element in the pressing action detecting direction based on a change in the second detected value corresponding to a change in position of the pointing element in the pressing action detecting direction; and a determining section (333) configured to (i) determine whether or not the pressing action with respect to the one switch by the pointing element is effective in accordance with whether or not the amount of movement is within a predetermined amount range.