Lightweight Antenna Shielding for Compact Head-Mounted Displays
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Solution Overview
Problem
It is challenging to incorporate antennas with satisfactory wireless performance into compact and lightweight head-mounted displays due to the presence of conductive components that can detune antenna performance and introduce noise or interference.
Innovation Solution
The use of a conductive shield formed from conductive traces patterned onto a dielectric carrier, which helps to mitigate electromagnetic interference, optimize the gain and radiation pattern of the antenna, and is lighter and less space-consuming than traditional folded sheet metal shields, while being integrated into the display's structure to minimize weight and maximize wireless performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional folded sheet metal shields are used to shield the antenna, then electromagnetic interference is mitigated, but the device weight and space consumption increase
Solution Approach 1:
The patent replaces the traditional mechanical folded sheet metal shield with a conductive shield formed from conductive traces patterned onto a dielectric carrier substrate. This substitution eliminates the need for heavy metal shielding while maintaining electromagnetic interference mitigation through the conductive trace pattern, directly resolving the contradiction between interference protection and weight reduction.
Solution Approach 2:
The conductive shield is implemented as a thin film structure where conductive traces are patterned onto a flexible or rigid dielectric carrier. This thin-film approach provides effective electromagnetic shielding with minimal thickness and weight, contrasting with the bulky folded sheet metal construction while maintaining the necessary shielding performance.
2Object-affected harmful factors
If traditional folded sheet metal shields are used to shield the antenna, then electromagnetic interference is mitigated, but the device volume increases
Solution Approach 1:
The patent replaces the voluminous folded sheet metal shield with a planar conductive trace pattern on a thin dielectric carrier. This substitution dramatically reduces the three-dimensional space required for shielding, allowing the antenna to be effectively shielded within the constrained volume of a head-mounted display device.
Solution Approach 2:
The invention transitions from three-dimensional folded metal shielding to a two-dimensional conductive trace pattern on a flat substrate. This dimensional reduction allows the shielding function to be integrated into the planar structure of the device without consuming additional volumetric space, effectively resolving the space constraint contradiction.
3Device complexity
If conductive components are placed near the antenna, then device integration is improved, but antenna performance is detuned and noise is introduced
Solution Approach 1:
The patent extracts the harmful electromagnetic effects from the vicinity of the antenna by introducing a conductive shield that isolates the antenna from nearby conductive components. The shield selectively blocks interfering electromagnetic fields while allowing the antenna to maintain its radiating function, thus separating the antenna's wireless performance from the detuning effects of adjacent conductive structures.
Solution Approach 2:
The conductive shield acts as an intermediary barrier between the antenna and other conductive components in the device. This intermediate structure mitigates the direct electromagnetic interaction that causes detuning and noise, allowing high-level integration of conductive components while preserving antenna performance through the mediating shield.
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 enhances the wireless performance of antennas in head-mounted displays by reducing interference from conductive components, maintaining a lightweight and compact form factor, and ensuring optimal radiation patterns, thus improving radio-frequency signal transmission and reception.
Implementation Method 1
The conductive shield may help to mitigate electromagnetic interference and noise from other components on the radio-frequency signals conveyed by the antenna
Implementation Method 2
The biasing member may press the flexible printed circuit against the cover
Data Source
AI summary
An electronic device may have first and second rear-facing displays, a front-facing display, a cover at a front side overlapping the front-facing display, and an antenna that radiates through the cover. The antenna may be formed from traces on a flexible printed circuit. The antenna may be provided with a conductive shield on a dielectric carrier. The flexible printed circuit may be mounted to the carrier opposite the shield. A biasing member may be mounted to the carrier and may press the flexible printed circuit against the cover. To minimize weight of the device, the shield may be formed from conductive traces patterned onto the carrier. The carrier may include first and second substrates formed from respective shots of co-molded plastic. The second substrate may include plateable grade plastic and the conductive traces may be patterned onto plateable outer surfaces of the second substrate opposite the first substrate.