Touch Panel Ground Electrode ESD Protection

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Solution Overview

Problem

Touch panels experience accuracy deterioration due to electric signal interference from static electricity or ESD, leading to non-uniform sensing and reduced reliability, especially when detecting touches near the center or with gloved hands.

Innovation Solution

Incorporating a first ground electrode between the sensing electrode and wire electrode to prevent static electricity and ESD interference, which is connected to the printed circuit board for discharge, ensuring uniform touch sensitivity and improved accuracy across the panel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ground electrode is added to prevent static electricity and ESD interference, then touch accuracy and reliability are improved, but device complexity increases

Engineering Contradiction:
Improvetouch accuracyVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The first ground electrode acts as an intermediary component between the sensing electrode and the wire, providing a shielding effect that prevents electric signal interference from static electricity and ESD. This mediator structure improves touch accuracy by blocking harmful electromagnetic interference without requiring fundamental changes to the existing touch panel architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The ground electrode is segmented into multiple regions: a first ground electrode disposed on the active area and a second ground electrode disposed on the inactive area. This segmentation allows the ground electrode to provide comprehensive ESD protection across different functional zones of the touch panel while maintaining manufacturing feasibility through standardized patterning processes.

Inventive Principle:
Principle #1Segmentation

2Area of stationary object

If the first ground electrode is disposed on the active area, then the active area is increased, but manufacturing precision requirements increase

Engineering Contradiction:
Improveactive areaVSAvoidpositioning precision
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The first ground electrode is configured to have substantially the same width as the sensing electrode, creating an equipotential shielding structure that effectively blocks ESD interference. This dimensional matching simplifies the manufacturing process by allowing the ground electrode to be aligned with the sensing electrode using existing registration marks, thereby reducing positioning precision requirements while maximizing the active area.

Inventive Principle:
Principle #12Equipotentiality

Solution Approach 2:

The ground electrode is strategically disposed only in regions where ESD protection is most critical - specifically on the active area where touch detection occurs and along the inactive area where wire connections are made. This localized approach increases the effective active area without requiring ground electrodes across the entire panel, thereby reducing overall manufacturing complexity.

Inventive Principle:
Principle #3Local quality

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

The first ground electrode enhances touch accuracy and reliability by preventing signal interference, allowing for precise detection of touches regardless of position and improving hovering and glove touch recognition, while also increasing the active area of the touch panel.

Implementation Method 1

the static electricity or ESD moves along a path of the first ground electrode, so that the static electricity or ESD can be prevented from being introduced into the touch panel. The first ground electrode is connected to the printed circuit board so that the ESD in the touch panel can be discharged as an electrical signal.

Methodology Applied
Scientific EffectElectrostatic Discharge: Electrostatic Discharge

Data Source

PatentEP2933712B1Touch panel
Publication Date: 2022.08.31 LG INNOTEK CO LTD
  • EP2933712B1 patent drawingFigure 1
  • EP2933712B1 patent drawingFigure 2
  • EP2933712B1 patent drawingFigure 3~4

AI summary

A touch panel of the embodiment includes a substrate (100); a sensing electrode (300) on the substrate (100); wires to electrically connect the sensing electrode (300); a first ground electrode (510) between the sensing electrode (300) and the wire (400); and an overlap part (OL) where the first ground electrode (510) overlaps with the sensing electrode (300). A touch panel of another embodiment includes a substrate (100) on which an active area (AA) and an unactive area (UA) are defined; a sensing electrode (300) on the active area (AA); a wire (400) disposed on the unactive area (UA) to electrically connect the sensing electrode (300); and a first ground electrode (510) disposed on the active area (AA) between the sensing electrode (300) and the wire (400).