Touch Module Equal Potential Wiring for Signal Cable Interference

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Solution Overview

Problem

Capacitive touch modules in electronic devices are susceptible to noise interference and sensing errors due to varying lengths of cables, which cause different degrees of electrostatic and electromagnetic interference, affecting the accuracy of touch position detection.

Innovation Solution

The touch module incorporates signal cables with shielding layers and equal potential wiring that bridges the shielding layers of any two signal cables, creating a short circuit and equalizing the potentials of the cables, thereby reducing the impact of environmental interference on signal quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple signal cables of different lengths are used to connect the touch panel and main circuit board, then the touch screen can be assembled with available cable lengths, but the cables experience different degrees of electrostatic and electromagnetic interference, causing potential differences that affect touch position accuracy

Engineering Contradiction:

Improvecable length adaptabilityVSAvoidtouch position accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies the equipotentiality principle by introducing an equal potential wiring that electrically connects the shielding layers of multiple signal cables. This creates a common potential reference among all cables, ensuring that even though cables have different lengths and experience different interference levels, their shielding layers maintain the same potential. This eliminates potential differences between cables and removes the source of measurement errors in touch position detection.

Inventive Principle:

Principle #12Equipotentiality

2Ease of operation

If cables with different lengths are used in the touch screen assembly, then assembly flexibility is improved, but the varying cable lengths cause different degrees of signal interference from the environment

Engineering Contradiction:

Improveassembly flexibilityVSAvoidsignal interference

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent uses the equal potential wiring as an intermediary element that mediates between the shielding layers of different signal cables. This intermediary connection ensures that all shielding layers share a common potential, effectively neutralizing the varying interference levels that different cable lengths experience. The equal potential wiring acts as a reference that equalizes the electrical environment across all cables.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the shielding layers of signal cables are left electrically isolated, then each cable can be independently shielded, but potential differences between cables cause troubles in judging the real touch position

Engineering Contradiction:

Improveindividual cable shieldingVSAvoidtouch position determination

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent merges the previously isolated shielding layers of multiple signal cables by introducing an equal potential wiring that electrically connects them all together. This merging creates a unified electrical reference system where all shielding layers share the same potential. The combination maintains the individual shielding effectiveness of each cable while adding the benefit of equalized potentials across the entire cable system.

Inventive Principle:

Principle #5Merging (Combining)

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 ensures that all signal cables experience similar levels of interference, allowing the touch module to accurately determine the touch position by minimizing the effects of electrostatic and electromagnetic disturbances.

Implementation Method 1

an equal potential wiring 226 used to electrically bridge the shielding layers 225 of any two signal cables 223, so that these shielding layers 225 form a short circuit between them

Methodology Applied

Scientific EffectElectrical Conduction: Conduction (electrical)

Implementation Method 2

each the signal cable 223 comprising a plurality of wire cores 224 arranged in parallel and a shielding layer 225 surrounding and covering at least a part of the wire cores 224

Methodology Applied

Scientific EffectElectromagnetic Shielding: Faraday Cage

Data Source

PatentUS12277289B2Touch module and touch screen using same

Publication Date: 2025.04.15 EGALAX EMPIA TECH INC

AI summary

The present invention relates to a touch module and a touch screen. The touch module includes a touch panel located on the display module, a main circuit board located outside the casing of the touch screen, a plurality of signal cables connecting the touch panel and the main circuit board, and an equal potential wiring. By setting an equal potential wiring in the touch module to electrically bridge any two signal cables, a short circuit is formed between the shielding layers of the signal cables so that the potentials of different signal cables can be equalized to make the signal cables roughly the same degree of electrostatic or electromagnetic interference from the environment. By making the signals obtained by the signal cables be disturbed to approximately the same degree, the touch module can accurately determine the touch position.