Display Touch Electrode Shielding for Low-Noise Recognition

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Solution Overview

Problem

Existing display devices face issues with signal interference between thin film transistors and touch electrodes, leading to noise in touch signals and visible recognition of touch electrode patterns, as well as increased resistance and RC delay in touch routing lines.

Innovation Solution

The display device incorporates a shielding electrode structure with first and second shielding electrodes that overlap the thin film transistor and touch electrodes, respectively, along with a mesh patterned touch electrode design and routing lines to minimize interference and reduce resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a touch electrode is disposed close to the thin film transistor to improve touch sensitivity, then touch recognition capability is improved, but signal interference and noise increase

Engineering Contradiction:

Improvetouch recognition capabilityVSAvoidsignal interference and noise

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

A shielding electrode is introduced as an intermediary component between the touch electrode and the thin film transistor. The shielding electrode is connected to a reference potential (ground) and acts as a mediator to block electromagnetic field interference from the transistor from reaching the touch electrode, thereby reducing noise while maintaining close proximity for sensitive touch detection

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The shielding electrode is strategically positioned only in specific regions where interference occurs most severely, particularly between the transistor and touch electrode. This localized approach provides targeted noise reduction without affecting the overall touch sensitivity or requiring comprehensive structural modifications

Inventive Principle:

Principle #3Local quality

2Reliability

If a continuous touch electrode structure is used to improve conductivity, then electrical conductivity is improved, but visibility of electrode patterns increases

Engineering Contradiction:

Improveelectrical conductivityVSAvoidvisibility of electrode patterns

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The touch electrode is divided into multiple separate segments or islands rather than using a continuous structure. Each segment maintains sufficient size for effective capacitive coupling with the finger, while the gaps between segments prevent the formation of visible continuous patterns on the display surface, thereby solving both conductivity and aesthetics issues

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A transparent conductive film is used as the touch electrode material, allowing the electrode structure to be thin and flexible. This enables the electrode to maintain electrical functionality while being optically transparent or having minimal visual impact, reducing the visibility of electrode patterns

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If touch routing lines are extended in the non-active area to connect touch electrodes, then touch electrode connectivity is improved, but resistance and RC delay increase

Engineering Contradiction:

Improvetouch electrode connectivityVSAvoidRC delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The routing strategy transitions from primarily horizontal or vertical routing to utilizing the vertical dimension by routing lines through the non-active area beneath the active display region. This three-dimensional routing approach shortens the effective path length and reduces the number of series connections required, thereby reducing total resistance and RC delay

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 configuration reduces noise in touch signals, suppresses visible recognition of touch electrode patterns, and stabilizes touch panel driving by minimizing RC delay and resistance in non-active areas.

Implementation Method 1

a first shielding electrode between the light emitting diode and the plurality of first touch electrodes overlapping a first touch electrode of the plurality of first touch electrodes, and a second shielding electrode between the light emitting diode and the plurality of first touch electrodes

Methodology Applied

Scientific EffectElectromagnetic shielding: Faraday Cage

Data Source

PatentUS12389779B2Display device with improved touch recognition capabilities

Publication Date: 2025.08.12 LG DISPLAY CO LTD

AI summary

The disclosure relates to a display device. In an embodiment, a display device includes a lower substrate including a plurality of sub pixels forming an active area and a non-active area enclosing the active area; a thin film transistor on the lower substrate corresponding to one of the plurality of sub pixels; a light emitting diode on the thin film transistor corresponding to the one of the plurality of sub pixels; a plurality of first touch electrodes on the light emitting diode corresponding to the active area; a plurality of second touch electrodes on the plurality of first touch electrodes corresponding to the active area; a first shielding electrode between the light emitting diode and the plurality of first touch electrodes overlapping a first touch electrode; and a second shielding electrode between the light emitting diode and the plurality of first touch electrodes, wherein the second shielding electrode does not overlap the first touch electrode.