Capacitive Sensor Signal Summation for Irregular Conductive Matter

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Solution Overview

Problem

Capacitive sensing devices face issues with false positives and incorrect touch location identification due to irregular conductive matter, such as water, which affects the accuracy and reliability of touch screens.

Innovation Solution

A capacitive sensing device and method that computes a signal summation at selected electrode lines to determine if a touch object is an irregular conductive matter by comparing the summation to a predetermined value, thereby distinguishing between regular and irregular conductive inputs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If capacitive sensing device uses conventional detection method, then it can detect touch input, but it produces false positives and false motion when irregular conductive matter is present

Engineering Contradiction:

Improvedetection accuracyVSAvoidfalse positives and false motion

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The sensing device divides the detection process into multiple stages: initial touch detection, signal summation calculation across multiple electrode lines, and threshold comparison. This segmentation allows the system to distinguish between regular touch inputs and irregular conductive matter by analyzing the distributed signal pattern across the electrode grid rather than relying on a single detection point.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediate processing step that calculates signal summation values for multiple sensing points along affected electrode lines. This intermediary calculation acts as a mediator between the raw capacitance change detection and the final touch validation, enabling the system to identify patterns characteristic of irregular conductive matter and filter them out before generating false positives.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If capacitive sensing device detects touch at touched location, then it identifies touch position, but irregular conductive matter causes connected conductive lines to be linked to adjacent axial conductive lines, rendering the control sensing circuit unable to identify the touched location correctly

Engineering Contradiction:

Improvetouch location identification accuracyVSAvoidcorrect touched location information

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The patent segments the electrode lines into multiple sensing points and calculates signal summation values for each affected electrode line independently. By analyzing the distribution of signal summation across multiple segmented sensing points rather than relying on a single location measurement, the system can distinguish between localized touch inputs and the distributed effect caused by irregular conductive matter connecting adjacent conductive lines.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system implements feedback by comparing the calculated signal summation against predetermined threshold values. This feedback mechanism allows the control sensing circuit to validate whether the detected signal pattern corresponds to a legitimate touch input or an irregular conductive matter artifact, thereby preventing incorrect location identification and maintaining measurement precision.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If conventional detection method is used, then the device responds to touch input, but it cannot distinguish between regular touch objects and irregular conductive matter

Engineering Contradiction:

Improvedetection capabilityVSAvoidobject identification accuracy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the detection parameter from simple capacitance change magnitude to signal summation values calculated across multiple sensing points on affected electrode lines. This parameter transformation enables the system to maintain high detection capability while improving object identification accuracy, as the distributed signal summation pattern differs characteristically between regular touch objects and irregular conductive matter.

Inventive Principle:

Principle #35Parameter changes

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 effectively reduces false motions and improves detection speed and efficiency by accurately identifying touch objects and ruling out irregular conductive matter interference.

Implementation Method 1

capacitive sensing device and detecting method for a conductive matter thereon

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

the equivalent circuit and equivalent parasitic capacitance between the axial conductive lines in the region change accordingly

Methodology Applied

Scientific EffectParasitic capacitance: Parasitic Capacitance

Data Source

PatentUS10185451B2Capacitance sensor device and detecting method for a conductive matter thereon

Publication Date: 2019.01.22 SALT INT CORP

AI summary

A detecting method for a conductive matter on a capacitive sensor device includes obtaining a positive signal, computing a signal summation of a plurality of sensing points in at least an electrode line where the positive signal is occurred, comparing the signal summation to a predetermined value, determining a touch object inducing the positive signal is not an irregular conductive matter if the signal summation is larger than the predetermined value, and determining the touch object inducing the positive signal is the irregular conductive matter if the signal summation is not larger than the predetermined value.