Conductive Housing Grounding Layout for Display EMI Reduction

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Solution Overview

Problem

Existing tuner devices face challenges in reducing unnecessary radiation due to high impedance areas within the metal housing, especially when the dimensions exceed half the wavelength of the highest oscillation frequency, and previous solutions involve complex configurations with numerous grounding sites, increasing costs and complexity.

Innovation Solution

A display device configuration where the conductive housing is designed with specific overlapping areas and grounding sites positioned at odd-numbered and even-numbered multiples of 1/4 wavelength distances to lower impedance and reduce radiation, allowing for simpler and less costly manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If the dimensions of the metal housing are reduced to be shorter than half the wavelength of the highest oscillation frequency, then unnecessary radiation is reduced, but the housing size cannot be made sufficiently small due to integration limits of capacitors and inductors

Engineering Contradiction:
Improveunnecessary radiationVSAvoidhousing size
Core Design Contradiction:
Object-generated harmful factorsVSVolume of moving object

Solution Approach 1:

The patent changes the grounding parameters by positioning grounding sites at specific distances (odd-numbered multiples of 1/4 wavelength) from high impedance areas, transforming the housing from a radiation source into an effective shield despite its larger size

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary grounding actions at strategically selected positions before radiation problems occur, placing grounding sites in advance at locations that will counteract high impedance areas and prevent unnecessary radiation

Inventive Principle:
Principle #10Preliminary action

2Object-generated harmful factors

If multiple grounding sites are added to reduce unnecessary radiation, then radiation is reduced, but the configuration becomes more complex and manufacturing costs increase

Engineering Contradiction:
Improveunnecessary radiationVSAvoidgrounding configuration complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies local quality by addressing only the specific high impedance areas that generate radiation, rather than uniformly grounding the entire housing, thus reducing complexity while maintaining effectiveness

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the grounding approach by identifying and treating only the critical high impedance regions with grounding sites, rather than applying a comprehensive grounding system across the entire housing structure

Inventive Principle:
Principle #1Segmentation

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

Effectively reduces unnecessary radiation even when housing dimensions exceed half the wavelength of the highest oscillation frequency, simplifying the configuration and reducing manufacturing costs by limiting the number of grounding sites.

Implementation Method 1

unnecessary radiation (EMI: electromagnetic interference) from a metal housing of the tuner device

Methodology Applied
Scientific EffectElectromagnetic interference: Electromagnetic Induction

Implementation Method 2

a range or site occurs in which the impedance is high in the metal housing, and a large amount of unnecessary radiation is produced from this range or site

Methodology Applied
Scientific EffectImpedance: Electrical Resistance

Data Source

PatentEP3490169B1Display device
Publication Date: 2020.07.29 FUNAI ELECTRIC CO LTD
  • EP3490169B1 patent drawingFigure 1
  • EP3490169B1 patent drawingFigure 2
  • EP3490169B1 patent drawingFigure 3

AI summary

A display device includes a signal processor, a display component, a substrate, and a conductive housing. The signal processor includes an oscillator that is configured to output oscillation signal. The signal processor is configured to process signal whose frequency is higher than a specific threshold. The display component is configured to display video. The substrate has a ground component. The signal processor is disposed on the substrate. The conductive housing is connected to a first site of the ground component and to a second site that is different from the first site. The first site and the second site are disposed at positions where a first area of the housing that is an odd-numbered multiple of 1/4 wavelength of the oscillation signal away from the first site overlaps at least part of a second area of the housing that is a multiple of 1/4 wavelength of the oscillation signal away from the second site.