Touch Panel Shield Layer Length Optimization for Noise Suppression

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Solution Overview

Problem

Existing touch panels experience noise peaks due to electromagnetic waves, which are not adequately suppressed by existing shield structures.

Innovation Solution

A touch panel design featuring a substrate with first and second detection electrodes, lead wires, and shield layers where the shield layers' lengths are optimized to prevent resonance with electromagnetic waves in the 100 MHz to 400 MHz frequency range, ensuring minimal noise generation in the lead wires.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If shield layers are added to reduce noise transmission to lead wires, then noise suppression is improved, but resonance phenomenon occurs at specific frequencies (100 MHz to 400 MHz)

Engineering Contradiction:
Improvenoise transmissionVSAvoidresonance phenomenon
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent changes the length parameter of the shield layer to be less than λ/4 (where λ is the wavelength of electromagnetic waves in the 100 MHz to 400 MHz range). This parameter modification prevents the shield layer from acting as a resonant antenna, thereby eliminating the resonance phenomenon while maintaining its noise shielding function.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If shield layers are positioned to overlap lead wires in plan view, then electromagnetic shielding is improved, but the shield layer itself becomes susceptible to resonance

Engineering Contradiction:
Improveelectromagnetic wave interferenceVSAvoidnoise generation in lead wires
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent modifies the length parameter of the shield layer, setting it to less than λ/4. This parameter change allows the shield layer to maintain its protective positioning over the lead wires while preventing resonance, thus achieving both electromagnetic shielding and noise suppression.

Inventive Principle:
Principle #35Parameter changes

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 optimized shield layer lengths effectively suppress noise phenomena caused by electromagnetic waves, enhancing the operational reliability of the touch panel.

Implementation Method 1

the shield layer is formed on the substrate so as to overlap the plurality of second lead wires in a plan view... in order that a resonance phenomenon does not occur

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Implementation Method 2

noise transmission to the second lead conductive pattern 64 is reduced. In addition, the second shield pattern 72 is disposed so as to correspond to the first lead conductive pattern 63. In this way, noise transmission to the first lead conductive pattern 63 is reduced.

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3232302B1Touch panel
Publication Date: 2020.01.01 NISSHA PRINTING CO LTD
  • EP3232302B1 patent drawingFigure 1
  • EP3232302B1 patent drawingFigure 2
  • EP3232302B1 patent drawingFigure 3

AI summary

To suppress noise phenomena caused by electromagnetic waves in a touch panel provided with shield layers corresponding to a wiring pattern. In this touch panel, a plurality of first transparent electrodes are formed on a first substrate film, and extend in one direction. A plurality of first wires are formed on the first substrate film, and are connected to the plurality of first transparent electrodes. A plurality of second transparent electrodes are formed so as to intersect the plurality of first transparent electrodes. A plurality of second lead wires are connected to the plurality of second transparent electrodes. A first shield layer and a second shield layer are formed on the first base-material film, and are arranged so as to overlap the plurality of second lead wires in a planar view. The first shield layer and the second shield layer have a length range set so as to not include lengths of λ of each of a plurality of frequencies within a specific range/n (n=2, 4, 6, ...), in order to not induce resonance phenomena with respect to the plurality of frequencies.