Capacitive Sensing Electrodes for Virtual Gesture Pad

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Solution Overview

Problem

Conventional user interfaces for mobile devices, such as mechanical sliders and sensor pads, are limited by their physical constraints, requiring precious real estate, being prone to wear, and inflexible in design, which hinders gesture recognition and user interaction.

Innovation Solution

Implementing a low complexity capacitive sensing system with two or more small capacitive sensing electrodes spaced apart, allowing for flexible placement and enabling gesture recognition without the need for physical contact with the sensor pads, by leveraging the space between electrodes to detect gestures using characteristic capacitive sensor measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional sensor pads are used for gesture recognition, then gesture detection capability is provided, but device real estate is consumed and design flexibility is reduced

Engineering Contradiction:

Improvedesign flexibilityVSAvoidsensor pad area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent extracts the essential sensing function from the conventional sensor pad by using only two capacitive sensing electrodes instead of a full sensor pad array. This extraction allows the system to maintain gesture recognition capability while eliminating the need for a large physical sensor pad area, thereby resolving the contradiction between design flexibility and area consumption.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a virtual sensor pad through algorithmic processing of capacitive measurements from two electrodes, rather than relying on a physical sensor pad surface. This virtual representation copies the sensing functionality without requiring the physical area, enabling flexible placement and design while maintaining gesture detection capability.

Inventive Principle:

Principle #26Copying

2Reliability

If physical sensor pads are used, then gesture recognition is enabled, but wear and reliability issues occur

Engineering Contradiction:

Improvesensor durabilityVSAvoidphysical contact requirement

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces the mechanical physical sensor pad with a capacitive sensing system that detects gestures through electrical field interactions. This substitution eliminates mechanical wear and contact requirements, improving reliability while maintaining ease of operation through non-contact gesture recognition.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If multiple small capacitive sensing electrodes are used, then virtual sensor pad flexibility is achieved, but measurement complexity increases

Engineering Contradiction:

Improveelectrode placement flexibilityVSAvoidgesture detection complexity

Core Design Contradiction:

Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent makes the two capacitive sensing electrodes universal by using them for multiple functions: gesture detection, virtual sensor pad creation, and adaptive interface positioning. This multi-functionality reduces the need for complex dedicated measurement systems for each function, managing complexity while achieving flexibility.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements feedback through algorithmic processing that continuously analyzes capacitive measurements from the two electrodes to determine gesture type, direction, and intensity. This feedback mechanism simplifies the measurement process by using computational algorithms rather than complex hardware, managing measurement complexity while enabling flexible electrode placement.

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

This approach provides a virtual sensor pad that is flexible in location and orientation, enhancing user interaction with improved reliability and ergonomics, allowing for accurate and efficient gesture recognition without the limitations of physical sensor pads, including the ability to recognize complex gestures and adapt to different user interfaces.

Implementation Method 1

capacitive sensing can provide a virtual sensor pad as a user interface. By implementing an algorithm which detects for three different conditions, the virtual sensor pad can be used effectively as a user interface modality to detect gestures

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS10359929B2Slider and gesture recognition using capacitive sensing

Publication Date: 2019.07.23 ANALOG DEVICES INC

AI summary

Conventional user interface for sensing gestures often require physical touching of a sensor pad, or an area filled with sensor pads. These conventional sensor pads take up precious real estate on a compact mobile device, interferes significantly with other components of the mobile device, complicates design, consumes power, and adds costs to the final product. With two or more small capacitive sensing electrodes placed on a mobile device (arbitrarily or with far less restrictions), capacitive sensing can provide a virtual sensor pad as a user interface. By implementing an algorithm which detects for three different conditions, the virtual sensor pad can be used effectively as a user interface modality to detect gestures such as a sliding gesture, drawing gesture, letters, writing, etc. The resulting virtual sensor pad can flexibly change to different desirable locations, and no longer suffers from the limitations of the conventional sensor pad.