Touch Screen Panel Shield Pattern Routing Wire Parasitic Capacitance

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Solution Overview

Problem

Capacitive touch screen panels face performance degradation due to parasitic capacitance between routing wires, leading to increased noise and reduced touch sensitivity.

Innovation Solution

Incorporating a grounding wire between routing wires and a shield pattern on an insulation layer to reduce parasitic capacitance and block external noise, with the shield pattern overlapping at least one of the routing wires and grounded through contact holes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If routing wires are arranged closely to reduce device area, then device complexity is reduced, but parasitic capacitance between routing wires increases leading to noise and reduced touch sensitivity

Engineering Contradiction:

Improvedevice areaVSAvoidparasitic capacitance and noise

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

A shield wire is introduced as an intermediary element between the first and second routing wires. This shield wire acts as a mediator that blocks electromagnetic interference and reduces parasitic capacitance between the adjacent routing wires, allowing them to be placed closer together without compromising signal quality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful electromagnetic fields and parasitic capacitance between routing wires into a beneficial shielding effect. By placing a grounded shield wire between the routing wires, the harmful electromagnetic interference is redirected to ground, transforming it into a protective barrier that reduces noise and improves touch sensitivity.

Inventive Principle:

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

2Manufacturing precision

If routing wires are placed close together to minimize space, then manufacturing precision requirements are reduced, but parasitic capacitance increases degrading touch performance

Engineering Contradiction:

Improverouting wire placement precisionVSAvoidtouch sensitivity

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The shield wire serves as an intermediary that compensates for the reduced spacing between routing wires. By introducing this intermediate shielding element, the system can tolerate less precise routing wire placement while maintaining low parasitic capacitance and high touch sensitivity, as the shield wire provides consistent electromagnetic isolation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If shield pattern is added to reduce parasitic capacitance, then touch sensitivity is improved, but device complexity increases

Engineering Contradiction:

Improvetouch sensitivityVSAvoidnumber of layers and patterns

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of providing uniform shielding across the entire device, the shield wire is strategically placed only in the critical regions where parasitic capacitance between routing wires most significantly impacts touch sensitivity. This localized shielding approach improves touch performance while minimizing the increase in device complexity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The shield wire is integrated with the existing routing wire structure and insulation layers, merging multiple functions into a compact design. The shield wire shares the same planar structure and manufacturing process as the routing wires, combining signal transmission and electromagnetic shielding functions without requiring separate complex shielding structures.

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

Significantly reduces parasitic capacitance and external noise, enhancing touch sensitivity and performance by shielding the routing wires.

Implementation Method 1

a shield pattern that is formed on the insulation layer in the routing wire area of the base layer, contacts the third wires through the contact holes, and overlaps at least either the first routing wires or the second routing wires

Methodology Applied

Scientific EffectElectromagnetic shielding: Faraday Cage

Implementation Method 2

a third wire formed in the routing wire area of the base layer and formed between the first routing wires and the second routing wires

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS9229554B2Touch screen panel for display device

Publication Date: 2016.01.05 LG DISPLAY CO LTD

AI summary

This disclosure relates to a touch screen panel for a display device. The touch screen panel includes a base layer, a plurality of first electrode strings, a plurality of second electrode strings, a plurality of first routing wires, a plurality of second routing wires; a third wire formed between the first routing wires and the second routing wires, an insulation layer that covers the first and second routing wires and the third wires and has contact holes exposing a part of the third wire, and a shield pattern that is formed on the insulation layer contacts the third wires through the contact holes, and overlaps either the first routing wires or the second routing wires.