Touch Panel Electrode Layout for External Noise Rejection

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Solution Overview

Problem

Existing touch panels and display units using electrostatic capacitance-type touch sensors face issues with erroneous detection due to external noise, particularly when the user acts as an antenna and transmits noise to the panel via their finger or other objects.

Innovation Solution

The implementation of a touch panel design that includes a plurality of detection scan electrodes and detection electrodes with different ratios of fringe capacitance to total capacitance, allowing for the selection of electrodes with varying sensitivities to contact/non-contact states and external noise, thereby eliminating noise from detection signals by calculating their difference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If electrostatic capacitance-type touch sensors are used to detect finger touches, then touch detection capability is improved, but susceptibility to external noise increases causing erroneous detection

Engineering Contradiction:

Improvetouch detection capabilityVSAvoiddetection accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The touch panel is divided into multiple detection regions with different electrode configurations. Specifically, the panel includes first detection electrodes and second detection electrodes with different fringe capacitance ratios, allowing segmentation of the detection function to handle different signal characteristics and noise levels in different regions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the touch panel are assigned different electrode designs with specific fringe capacitance ratios. The first detection electrodes have a different ratio compared to the second detection electrodes, optimizing each region's sensitivity and noise rejection characteristics according to local requirements.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If the user touches the panel with a finger to enter information, then ease of operation is improved, but external noise is transmitted via the finger causing erroneous detection

Engineering Contradiction:

Improvetouch input capabilityVSAvoidexternal noise transmission

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The invention converts the harmful effect of the user's body acting as an antenna into a beneficial feature by using the user's finger capacitance as part of the detection mechanism. The different fringe capacitance ratios in different electrode regions help distinguish between intentional touch signals and noise transmitted through the user's body.

Inventive Principle:

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

Solution Approach 2:

The invention changes the capacitance parameters of the detection electrodes by using different fringe capacitance ratios. This parameter variation allows the system to differentiate between genuine touch inputs and noise signals, maintaining ease of operation while reducing erroneous detection.

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 eliminates external noise from detection signals, preventing erroneous touch detections and enhancing the reliability of touch-based interactions in display devices.

Implementation Method 1

A popularized touch sensor is, for example, of an electrostatic capacitance type. A touch sensor of this type catches, by a capacitive element, a change occurring in the surface electric field of a panel when a touch panel is touched with a finger or the like

Methodology Applied

Scientific EffectElectrostatic capacitance: Capacitance

Implementation Method 2

A ratio of fringe capacitance to total capacitance between one or more selected detection scan electrodes and the first detection electrode is different from a ratio of fringe capacitance to total capacitance between the one or more selected detection scan electrodes and the second detection electrode

Methodology Applied

Scientific EffectFringe capacitance: Capacitance

Data Source

PatentUS20250173032A1Touch panel, display panel, and display unit

Publication Date: 2025.05.29 MAGNOLIA WHITE CORP

AI summary

A touch panel, a display panel, and a display unit achieving prevention of erroneous detection caused by external noise. The touch panel includes: a plurality of detection scan electrodes extending in a first direction and a plurality of detection electrodes facing the plurality of detection scan electrodes and extending in a second direction which intersects the first direction. The one or more selected detection scan electrodes are selected, in a desired unit, from the plurality of detection scan electrodes, to be supplied with a selection pulse, and each of the first and the second detection electrodes is selected from the plurality of detection electrodes.