Conductive Fan Rotor Shielding for EMI Vent Apertures
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Solution Overview
Problem
Conventional EMI shielding systems in electronic devices, such as computing devices and gaming consoles, face inefficiencies due to their construction, which impedes airflow and hinders thermal efficiency while failing to effectively prevent electromagnetic interference (EMI) leakage through apertures used for ventilation.
Innovation Solution
The implementation of an EMI attenuation device with a housing stator, a fan rotor, and an electrical bridge that provides an electrically conductive path between the rotor and the stator, allowing rotation while limiting EMI transmission through the aperture by creating channels with a specific transverse to longitudinal dimension ratio, thereby maintaining airflow and thermal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an EMI shielding mesh with perforated metal holes is used near the fan or blower, then EMI shielding is provided, but air flow is impeded and thermal efficiency is hindered
Solution Approach 1:
The patent applies a flexible conductive membrane that can be positioned near the fan or blower aperture. This membrane provides EMI shielding while being flexible enough to allow air flow through the aperture, thus resolving the contradiction between EMI shielding effectiveness and air flow maintenance. The membrane acts as a selective barrier that blocks electromagnetic interference while permitting thermal management functions.
Solution Approach 2:
The patent modifies the parameters of the shielding structure by using a flexible conductive membrane with specific electrical conductivity and permeability characteristics. By changing the physical and electrical parameters of the shielding material, the system achieves effective EMI attenuation while maintaining adequate air flow for thermal management, thus resolving the contradiction between shielding performance and airflow requirements.
2Object-affected harmful factors
If a conventional EMI shielding structure is used, then EMI attenuation is achieved, but the structure impedes air flow and reduces thermal efficiency
Solution Approach 1:
The flexible conductive membrane serves as a thin film shielding solution that provides EMI attenuation without significantly impeding air flow. This allows heat dissipation to occur effectively while maintaining electromagnetic shielding, thus resolving the contradiction between EMI attenuation and thermal efficiency.
Solution Approach 2:
The flexible conductive membrane acts as an intermediary element between the EMI shielding requirement and the thermal management requirement. It mediates between these two conflicting demands by providing electromagnetic shielding while allowing heat transfer and air flow to proceed effectively, thus resolving the contradiction between EMI attenuation and thermal efficiency.
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 solution effectively attenuates EMI by at least 20 dB across various frequency ranges while maintaining airflow and thermal management, enhancing the performance of electronic devices by preventing EMI leakage and heat dissipation.
Implementation Method 1
an electrical bridge between the proximate surface of the fan rotor and a contact surface of the housing stator
Implementation Method 2
The fan rotor is electrically conductive, and the proximate surface is continuous around a rotational direction of the fan rotor
Data Source
AI summary
An EMI attenuation device includes a housing stator, a fan rotor, and an electrical bridge therebetween. The housing stator has an aperture therethrough, and at least a portion of the housing stator is electrically conductive. The fan rotor is adjacent to the aperture and has a rotational axis relative to the housing stator and a proximate surface proximate the housing stator. The fan rotor is electrically conductive, and the proximate surface is continuous around a rotational direction of the fan rotor. The electrical bridge is between the proximate surface of the fan rotor and a contact surface of the housing stator.