Interference Sensing Capacitor for Display Touch Noise Isolation

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Solution Overview

Problem

Parasitic capacitors between display electrodes and touch sensing layers in display-and-touch systems cause noise interference, degrading touch sensing performance, especially as panels become thinner and more susceptible to noise from display electrodes.

Innovation Solution

Incorporating an interference sensing capacitor connected to the display panel's interference layer, which is insensitive to touches and other interference sources, allowing for accurate noise elimination from touch sensing signals by isolating noise from the display panel's interference layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the display panel is made thinner to improve portability and design, then the panel becomes more susceptible to noise interference from display electrodes, but this degrades touch sensing performance

Engineering Contradiction:

Improvepanel thicknessVSAvoidtouch sensing accuracy

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

An interference sensing capacitor is introduced as an intermediary component between the display electrode and the touch sensing electrode. This capacitor specifically senses the noise signal from the display electrode through its parasitic capacitance, allowing the noise to be detected and eliminated without affecting the normal touch sensing function. The intermediary capacitor acts as a dedicated noise detection channel that separates the noise sensing function from the touch sensing function.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The noise signal from the display electrode is extracted and sensed separately using the interference sensing capacitor. By taking out the noise component through this dedicated capacitor, the system can process and eliminate the noise independently from the touch sensing signal, thereby preserving touch sensing accuracy even in thinner panel designs where parasitic capacitance is more significant.

Inventive Principle:

Principle #2Taking out (Extraction)

2Ease of manufacture

If display electrodes and touch sensing layers are placed closer together to improve integration, then manufacturing complexity is reduced, but parasitic capacitors increase causing more noise interference

Engineering Contradiction:

Improveintegration of display and touch layersVSAvoidnoise interference from parasitic capacitors

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The parasitic capacitance between the display electrode and the interference sensing capacitor, which would normally be a harmful noise source, is converted into a useful sensing mechanism. By intentionally designing the interference sensing capacitor to utilize this parasitic capacitance, the system transforms the harmful noise coupling into a beneficial noise detection pathway, allowing the noise to be sensed and eliminated through the dedicated interference sensing channel.

Inventive Principle:

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

3Device complexity

If traditional touch sensing methods are used without interference sensing, then the device structure remains simple, but touch sensing accuracy is degraded by noise from the display panel

Engineering Contradiction:

Improvestructure of touch control circuitVSAvoidtouch sensing accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The touch control circuit is segmented into separate functional channels: a dedicated interference sensing channel for detecting noise from the display electrode, and separate touch sensing channels for detecting actual touch inputs. This segmentation allows the noise detection and elimination function to operate independently without interfering with the touch sensing function, improving accuracy while maintaining relatively simple circuit architecture.

Inventive Principle:

Principle #1Segmentation

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 solution significantly improves the accuracy of touch sensing results by isolating and eliminating noise from the display panel's interference, enhancing the reliability of touch events detection in display-and-touch systems.

Implementation Method 1

at least one interference sensing capacitor configured to be insensitive to a touch on the touch panel and interference other than interference from an interference layer of the display panel

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS11726616B2Display-and-touch system having interference sensing capacitor

Publication Date: 2023.08.15 NOVATEK MICROELECTRONICS CORP

AI summary

A touch control circuit, display-and-touch system, touch panel and touch sensing method are disclosed. The system includes a display panel, a touch panel having a plurality of touch sensors, a touch control circuit and at least one interference sensing capacitor configured to be insensitive to a touch on the touch panel and interference other than the interference from an interference layer of the display panel, the touch control circuit includes: at least one interference sensing channel configured to receive an interference sensing signal from the at least one interference sensing capacitor; and a plurality of touch sensing channels configured to receive touch sensing signals from at least part of touch sensors of the plurality of touch sensors; wherein a first electrode of each interference sensing capacitor is connected with the interference layer of the display panel, and a second electrode thereof is connected with a corresponding interference sensing channel.