Matrix Electrode Design for 3D Electric Field Sensor Gesture Recognition

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Solution Overview

Problem

Current three-dimensional electric field sensors face challenges in achieving a significant larger range and accurate gesture recognition due to limitations in electrode sensitivity profiles, particularly the 1/d^2 decline in E-field strength with distance, leading to ambiguous position tracking and sensitivity profile dependency on hand position.

Innovation Solution

The introduction of a matrix electrode structure with capacitive coupling between electrodes, where the second electrode is electrically floating or has high impedance, and the use of discrete capacitors or capacitive coupling paths to combine signals with controllable weights, enhancing sensitivity profiles and achieving a more constant signal deviation over distance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional single electrode arrangement is used, then the device structure is simple, but the measurement range is limited and sensitivity profile depends on hand position

Engineering Contradiction:
Improvemeasurement rangeVSAvoidelectrode structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The electrode structure is segmented into multiple receiving electrodes (first receiving electrode and second receiving electrode) arranged in different directions. Each electrode captures field disturbances from its specific orientation, and their combined signals provide comprehensive three-dimensional gesture detection, extending the effective measurement range while maintaining structural manageability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-electrode arrangement to a multi-electrode matrix structure with electrodes extending in different directions (first direction and second direction). This dimensional expansion creates a more comprehensive sensing volume, allowing the system to detect gestures from multiple spatial perspectives simultaneously, thereby significantly extending the measurement range

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

2Measurement precision

If electrodes are arranged to detect three-dimensional gestures, then gesture recognition capability is improved, but sensitivity profile dependency on hand position causes ambiguous position tracking

Engineering Contradiction:
Improveposition tracking accuracyVSAvoidsensitivity profile ambiguity
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent combines signals from multiple receiving electrodes (first receiving electrode and second receiving electrode) oriented in different directions. By merging these complementary signal sources, the system creates a unified sensitivity profile that eliminates directional dependencies and ambiguities, resulting in accurate three-dimensional position tracking without information loss

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent modifies the sensitivity profile characteristics by combining signals from electrodes with different orientations. This parameter transformation converts the individual direction-dependent sensitivity profiles into a composite profile that maintains consistent sensitivity across different hand positions, eliminating tracking ambiguities

Inventive Principle:
Principle #35Parameter changes

3Length of stationary object

If the range of electric field sensing is extended, then more gestures can be detected, but the E-field strength declines with distance following 1/d^2 law

Engineering Contradiction:
Improvedetection rangeVSAvoidE-field strength
Core Design Contradiction:
Length of stationary objectVSPower

Solution Approach 1:

The patent combines signals from multiple receiving electrodes positioned to detect field disturbances from different directions. This signal merging approach effectively integrates the weak field information from extended distances, compensating for the 1/d^2 field strength decline and enabling reliable detection across a significantly extended range

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 significantly improves the range of three-dimensional electric near-field measurement by up to 50% and provides more accurate position tracking and gesture recognition by maintaining a linear sensitivity profile, reducing ambiguity and enhancing detection accuracy.

Implementation Method 1

a transmitting electrode configured to generate a quasi-static alternating electric field which extends into an observation area

Methodology Applied
Scientific EffectQuasi-static alternating electric field: Electric Field

Implementation Method 2

the first and second electrodes can be combined by capacitively coupling the second electrode with the first electrode

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentEP2972710B1Matrix electrode design for three-dimensional e-field sensor
Publication Date: 2021.02.17 MICROCHIP TECHNOLOGY INC
  • EP2972710B1 patent drawingFigure 1
  • EP2972710B1 patent drawingFigure 2~3
  • EP2972710B1 patent drawingFigure 4a~4c

AI summary

An electrode arrangement has a transmitting electrode configured to generate a quasi-static alternating electric field which extends into an observation area, a first electrode extending in a first direction and configured to be connected to an evaluation device as a receiving electrode, and a second electrode extending in a second direction different from the first direction wherein for evaluating disturbances of the quasi-static alternating electric field an enhanced sensitivity profile is obtained by combining the first and second electrode.