Touch Ground Layer for Display Device ESD Protection

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Solution Overview

Problem

Display devices with touchscreens face issues with electrostatic charge diffusion affecting screen quality and circuit reliability, leading to potential malfunctions and degradation.

Innovation Solution

A display device design incorporating a touch ground layer that overlaps with the panel ground layer and electrode layer, along with a polarization plate and optically clear adhesive layers, to efficiently discharge static electricity and prevent charge induction or diffusion to the circuit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a touchscreen is added to a display device, then user input capability is improved, but electrostatic charge diffusion occurs affecting screen quality and circuit reliability

Engineering Contradiction:

Improveuser input capabilityVSAvoidcircuit reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

A ground layer is introduced as an intermediary component between the touchscreen electrode and the display circuit. This ground layer acts as a mediator that intercepts and dissipates electrostatic charges before they can reach and affect the underlying circuit, thus protecting circuit reliability while maintaining touchscreen functionality

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful electrostatic charge accumulation into a beneficial grounding mechanism. By providing a dedicated ground layer that attracts and dissipates static charges, the harmful electrostatic effect is transformed into a protective function that actually improves overall system reliability

Inventive Principle:

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

2Reliability

If ground electrodes are placed close to sensing electrodes for ESD protection, then electrostatic discharge protection is improved, but coupling between sensing electrode and ground electrode increases causing quality issues

Engineering Contradiction:

Improveelectrostatic discharge protectionVSAvoidscreen quality degradation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The ground layer is designed with spatially varying properties: in regions close to the sensing electrode, it provides strong ESD protection through proximity, while in other regions it maintains appropriate spacing to avoid coupling effects. This local differentiation allows the ground layer to perform different functions in different zones, optimizing both protection and quality

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

This design effectively suppresses electrostatic charge diffusion to the circuit, maintaining screen quality and minimizing adverse effects on circuit reliability, such as malfunction or degradation.

Implementation Method 1

Methodology Applied

Scientific EffectElectrostatic discharge: Electrostatic Discharge

Data Source

PatentEP3789860B1Display device with touchscreen

Publication Date: 2023.11.01 LG DISPLAY CO LTD

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AI summary

A display device with a touchscreen is provided. The display device includes a display panel having an electrode layer in a display area and a non-display area thereof, and a panel ground layer in the non-display area; and a touchscreen over the display panel and including a touch ground layer having an area overlapping with at least one of the electrode layer and the panel ground layer.