Touch Sensing Device Noise Determination Circuit

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Solution Overview

Problem

Touch sensing devices face noise interference from display panels, leading to errors and unintended user inputs, particularly when the display panel's screen pattern generates significant noise, causing 'ghost touches' and potential device malfunctions.

Innovation Solution

A touch sensing device with a receiving circuit for differential mode sensing and a noise determination circuit that assesses noise levels using reference sensing values, allowing for adaptive noise filtering without additional devices, ensuring stable and flexible touch performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the display panel uses a thin stack structure to reduce display module thickness, then the display module becomes more compact, but noise generation in the touch panel increases

Engineering Contradiction:

Improvedisplay module thicknessVSAvoidnoise generation

Core Design Contradiction:

Length of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful noise signal into a useful reference for noise filtering. By using the noise signal itself as a reference parameter, the system can dynamically adjust filtering strength to eliminate ghost touches while preserving legitimate touch inputs, thus turning the harmful noise into a beneficial control signal.

Inventive Principle:

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

Solution Approach 2:

The patent dynamically changes the noise filtering parameter based on the detected noise level. When noise is detected, the filtering strength is increased; when noise is absent, filtering is reduced or disabled. This adaptive parameter adjustment allows the system to maintain compact display structure while managing noise interference.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If noise filtering is applied to eliminate ghost touches, then touch accuracy improves, but legitimate touch inputs may be filtered out

Engineering Contradiction:

Improvetouch accuracyVSAvoidtouch input reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent implements dynamic noise filtering where the filtering strength is continuously adjusted based on real-time noise detection. The system transitions between different filtering states (strong filtering when noise is detected, weak or no filtering when noise is absent), allowing it to distinguish between noise-induced false touches and legitimate user inputs adaptively.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system uses feedback from noise level detection to control the filtering process. The noise determination circuit provides feedback about the current noise environment, which then adjusts the filtering parameter in the receiving circuit, creating a closed-loop system that maintains both accuracy and reliability.

Inventive Principle:

Principle #23Feedback

3Reliability

If additional noise filtering devices are added to reduce noise impact, then touch performance improves, but device complexity increases

Engineering Contradiction:

Improvetouch performanceVSAvoiddevice structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the existing sensing electrode serve multiple functions: it detects both touch inputs and noise levels. By using the same electrode for both purposes, the system avoids adding separate noise detection devices, thus maintaining simplicity while achieving reliable noise-based adaptive filtering.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses its own internal signals (the noise signal from the display panel) as the reference for filtering, rather than requiring external noise reference devices. The noise determination circuit utilizes the existing sensing infrastructure to self-assess noise levels and control filtering accordingly.

Inventive Principle:

Principle #25Self-service

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 dynamically adapts to varying noise levels, enhancing touch performance reliability by minimizing noise impact and eliminating the need for extra components, thus improving accuracy and reducing power consumption.

Implementation Method 1

a receiving circuit configured to receive a first sensing value generated in a differential mode using a first input signal input to the first sensing electrode and a second input signal input to the second sensing electrode

Methodology Applied

Scientific EffectDifferential mode sensing:

Implementation Method 2

a noise determination circuit configured to receive a reference sensing value generated using the second input signal and determining the amount of noise of the first sensing value using the reference sensing value

Methodology Applied

Scientific EffectNoise measurement:

Data Source

PatentUS12260047B2Touch sensing device and touch sensing method

Publication Date: 2025.03.25 LX SEMICON CO LTD

AI summary

Touch sensing device and touch sensing method are disclosed. A touch sensing device according to the present disclosure may include a receiving circuit configured to receive a first sensing value generated in a differential mode using a first input signal input to the first sensing electrode and a second input signal input to the second sensing electrode; and a noise determination circuit configured to receive a reference sensing value generated using the second input signal and determining the amount of noise of the first sensing value using the reference sensing value.