Loop RX Electrode Layout for Capacitive Touch Noise Cancellation

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Solution Overview

Problem

Conventional capacitive touch sensors experience weak Coulomb forces between segmented electrodes and are susceptible to external noise, leading to immunity issues.

Innovation Solution

The RX electrode is designed with a loop antenna shape formed by conductors that induce current flows in opposite directions to offset electric fields, reducing susceptibility to external noise, and includes a TX electrode and ground conductors to enhance noise resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If three segmented electrodes are used in conventional capacitive touch sensors, then the electrode structure is simpler, but the sensor is more susceptible to external noise and generates weak Coulomb forces between adjacent electrodes

Engineering Contradiction:

Improveelectrode structureVSAvoidexternal noise susceptibility

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The RX electrode is divided into multiple conductors (first conductor, second conductor, third conductor, fourth conductor) arranged in a specific loop configuration. This segmentation allows each conductor to contribute to noise cancellation while maintaining overall electrode functionality, resolving the contradiction between structural simplicity and noise resistance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention converts the harmful effect of external noise into a beneficial one by designing the loop antenna structure where external noise induces current flows in opposite directions through adjacent conductors. These induced currents generate electric fields that offset each other, transforming noise susceptibility into an active noise cancellation mechanism.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Ease of manufacture

If conventional segmented electrodes are used, then manufacturing is easier, but Coulomb forces between adjacent electrodes are weak

Engineering Contradiction:

Improveelectrode fabricationVSAvoidCoulomb force between electrodes

Core Design Contradiction:

Ease of manufactureVSForce

Solution Approach 1:

The loop antenna structure with multiple conductors connected in series creates equipotential regions that enhance the electric field distribution between adjacent conductors. This configuration strengthens the Coulomb forces between electrodes while maintaining manufacturability through standard PCB fabrication techniques.

Inventive Principle:

Principle #12Equipotentiality

3Object-affected harmful factors

If a loop antenna shape is formed with multiple conductors, then external noise susceptibility is reduced, but the electrode structure becomes more complex

Engineering Contradiction:

Improveexternal noise resistanceVSAvoidelectrode configuration

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention merges the functions of multiple conductors into a unified loop antenna structure that performs both signal reception and noise cancellation simultaneously. By connecting the first, second, third, and fourth conductors in a loop configuration, the structure achieves enhanced noise resistance without requiring separate noise cancellation components, thus managing complexity through functional integration.

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 RX electrode effectively reduces external noise interference, improving EMC resistance and accuracy in detecting touch inputs by minimizing signal fluctuations due to noise and conductor deposits.

Implementation Method 1

application of external noise to the electrode body induces current flows in opposite directions through the first and second conductors, so that an electric field generated in the first conductor and an electric field generated in the second conductor offset each other

Methodology Applied

Scientific EffectElectric field offset: Electric Field

Implementation Method 2

application of external noise to the electrode body induces current flows in opposite directions through the first and second conductors

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS12360644B2RX electrode for capacitive touch sensor, capacitive touch sensor, and noise reduction method

Publication Date: 2025.07.15 HOSIDEN CORP

AI summary

An RX electrode for a capacitive touch sensor including an electrode body, which includes first to fourth conductors, one of which includes a connecting portion. The first and second conductors are arrayed and located close to each other with a gap therebetween in a first direction, extend in a second direction. Application of external noise to the electrode body induces current flows in opposite directions through the first and second conductors, so that an electric field generated in the first conductor and an electric field generated in the second conductor offset each other. The third conductor, located on the one side in the second direction relative to the gap, connects first end portions of the first and second conductors. The fourth conductor, located on the other side in the second direction relative to the gap, connects second end portions of the first and second conductors.