Touch Screen EMI Shielding via Metal Frame Integration

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Solution Overview

Problem

Current methods for shielding electromagnetic interference (EMI) in touch-control screens, such as using conductive and light-penetrable shield layers, are costly and complex, and do not effectively address the interference affecting mobile communications devices.

Innovation Solution

A touch-control screen design incorporating a metal frame that encloses a liquid crystal display and a transparent conductive shield layer electrically connected to the frame, which absorbs and directs EMI to a ground cable, forming an integrated shielding structure with a silicon dioxide layer and through-holes for improved connectivity and reduced leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a conductive and light-penetrable shield layer is added between the touch-control panel and the liquid crystal display, then electromagnetic interference shielding is improved, but manufacturing cost increases

Engineering Contradiction:
Improveelectromagnetic interference shieldingVSAvoidmanufacturing cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent combines the shield layer with the metal frame structure to form an integrated shielding system. The shield layer is electrically connected to the metal frame, merging two separate shielding approaches (conductive layer and metallic enclosure) into a unified structure that achieves effective EMI shielding without requiring a separate expensive conductive shield layer between the touch panel and display

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a grounding system as an intermediary element. The shield layer is electrically connected to the metal frame which is in turn connected to ground, creating a mediated shielding path that effectively directs electromagnetic interference to ground without requiring direct contact between the shield layer and ground, simplifying the manufacturing process

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a conductive and light-penetrable shield layer is added between the touch-control panel and the liquid crystal display, then electromagnetic interference shielding is improved, but device complexity increases

Engineering Contradiction:
Improveelectromagnetic interference shieldingVSAvoidshielding structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the shield layer with the existing metal frame and grounding system, eliminating the need for separate shielding components. This integration reduces device complexity by utilizing already-present structural elements for shielding purposes rather than adding independent shielding subsystems

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The metal frame serves multiple functions: it provides structural support, acts as an EMI shield, and serves as a grounding path. This multi-functionality reduces device complexity by eliminating the need for separate components dedicated to each function

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If the shield layer is electrically connected to the metal frame and ground cable, then electromagnetic interference shielding effectiveness is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveelectromagnetic interference shielding effectivenessVSAvoidelectrical connection complexity
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The metal frame acts as an intermediary element that simplifies electrical connections. Instead of directly connecting the shield layer to the ground cable (which would require precise positioning and complex wiring), the shield layer connects to the metal frame which is already structurally positioned and can be easily grounded, significantly reducing manufacturing complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

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 shields EMI generated by the liquid crystal display, simplifies manufacturing processes, and reduces costs while maintaining the touch-control functionality and light transmission, thereby enhancing the performance of mobile communications devices.

Implementation Method 1

a transparent conductive shield layer electrically connected to the frame, which absorbs and directs EMI to a ground cable

Methodology Applied
Scientific EffectElectromagnetic interference shielding: Electromagnetic Induction

Implementation Method 2

electromagnetic interference generated by the liquid crystal display

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Data Source

PatentEP2703964B1Touch-control screen and mobile communications device
Publication Date: 2017.11.22 HUAWEI DEVICE CO LTD
  • EP2703964B1 patent drawingFigure 1
  • EP2703964B1 patent drawingFigure 2
  • EP2703964B1 patent drawingFigure 3

AI summary

The present utility model provides a touch-control screen and a mobile communications device, and relates to the touch-control display field. The touch-control screen and the mobile communications device are capable of effectively shielding electromagnetic interference generated by a liquid crystal display and have the benefits of simple processing techniques and low costs. The touch-control screen includes: a metal frame, the liquid crystal display embedded into the metal frame, and a touch-control panel covering the liquid crystal display, where the touch-control panel includes a transparent conductive shield layer, and the transparent conductive shield layer is electrically connected to the metal frame. A mobile communications device includes the touch-control screen.