Transmitter Frequency Adaptation for Stylus Interference

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Solution Overview

Problem

Capacitive touch sensitive screens face challenges in accurately detecting stylus inputs due to interference from electromagnetic signals and the inability to differentiate between finger and stylus touches, which affects precision and functionality, especially in professional graphics and typesetting applications.

Innovation Solution

A transmitter system that includes a transmitting module to send electrical signals with specific frequencies, a detecting module to identify interference signals, and a processing module to replace detected frequencies, allowing the touch sensitive device to differentiate between stylus and finger inputs while mitigating electromagnetic interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electromagnetic interference is present in the environment, then the touch sensitive screen can detect signals, but the detection accuracy deteriorates due to coherent interference signals

Engineering Contradiction:

Improvesignal detection capabilityVSAvoidstylus detection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary detection of interference signals during idle periods (when no transmission is occurring) and pre-adjusts the frequency selection before actual stylus detection begins, ensuring accurate detection even in interfering environments

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically changes the frequency parameter of the electrical signal based on detected interference conditions, selecting alternative frequencies from a predetermined set to avoid coherent interference and maintain detection accuracy

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the touch sensitive screen uses capacitive detection method, then it can detect finger touches, but it cannot accurately differentiate between finger and stylus inputs

Engineering Contradiction:

Improvetouch input compatibilityVSAvoidinput differentiation accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system segments the touch input detection into two distinct phases: capacitive detection for general touch identification, and inductive detection for stylus-specific identification, allowing accurate differentiation while maintaining versatility

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The transmitter introduces an intermediate electromagnetic signal that acts as a mediator between the stylus and the touch sensitive screen, enabling the screen to distinguish stylus inputs from finger touches through inductive coupling detection

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If the transmitter uses fixed frequency signals, then the transmission is simple, but the system cannot avoid electromagnetic interference

Engineering Contradiction:

Improvetransmission system simplicityVSAvoidinterference resistance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system transitions from static fixed-frequency transmission to dynamic frequency selection, where the transmission frequency is adjusted in real-time based on detected interference conditions, maintaining simplicity while improving reliability

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The transmitter is designed with multi-functionality, capable of both simple fixed-frequency operation and adaptive frequency switching, allowing it to function effectively in both interference-free and interfering environments

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Enables accurate detection of stylus inputs and button states on capacitive touch sensitive screens, even in environments with electromagnetic interference, improving precision and functionality for professional applications.

Implementation Method 1

a detecting module configured to detect an interference signal coherent to the electrical signal from a received signal external to the transmitter

Methodology Applied

Scientific EffectCoherent interference: Resonance

Data Source

PatentUS9823791B2Transmitter, touch sensitive system and transmitting method thereof

Publication Date: 2017.11.21 EGALAX EMPIA TECH INC

AI summary

The present invention provides a transmitter, which includes a transmitting module configured to transmit an electrical signal to a touch sensitive device according to at least one transmitter operating status such that the touch sensitive device acknowledges the transmitter operating status by analyzing the electrical signal including one or more first frequencies; a detecting module configured to detect an interference signal coherent to the electrical signal from a received signal external to the transmitter when the transmitting module is not transmitting the electrical signal; and a processing module configured to replace the detected one or more first frequencies with one or more second frequencies in response to the interference signal being detected by the detecting module.