Magnetic Backing Plate for Transmitter Inductance and Shielding
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Solution Overview
Problem
Magnetic field transmitters used in wireless communications earplugs are less efficient due to larger coil sizes generating more unused magnetic flux, leading to reduced battery life in battery-operated devices, especially in applications where space is limited.
Innovation Solution
Incorporating a plate of magnetic material behind the coil to improve efficiency and provide electrical and magnetic shielding, with specific coil geometry and dimensions that enhance wireless communications, including the use of a cup-shaped magnetic backing plate and perforations to reduce weight and maintain inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a larger transmitter coil is used, then the coverage area is increased, but the efficiency decreases due to more unused magnetic flux
Solution Approach 1:
The magnetic field distribution is segmented into useful and unused portions. The cup-shaped backing plate segments the magnetic flux paths, directing them through the plate to reduce unused flux while maintaining large coverage area.
Solution Approach 2:
The flat coil is enhanced by adding a three-dimensional cup-shaped backing plate structure. This adds a vertical dimension to the magnetic circuit, creating a more efficient flux path that reduces losses while maintaining horizontal coverage.
2Loss of energy
If a smaller transmitter coil is used, then the efficiency is improved, but the coverage area is reduced
Solution Approach 1:
The cup-shaped magnetic backing plate acts as an intermediary between the small coil and the surrounding space. It extends the magnetic field distribution and provides a low-reluctance path that effectively increases the coverage area without requiring a larger coil.
3Reliability
If a solid magnetic backing plate is used, then the magnetic shielding and inductance are improved, but the weight increases
Solution Approach 1:
The solid magnetic backing plate is replaced with a perforated version that has holes or openings. This porous structure reduces weight while maintaining the magnetic shielding function and inductance enhancement, as the magnetic flux paths are preserved through the plate structure.
4Volume of moving object
If the transmitter coil size is increased to fit around the pinna, then the spatial constraint is resolved, but the efficiency decreases
Solution Approach 1:
The magnetic properties are concentrated locally in the cup-shaped backing plate behind the coil. This creates a high-efficiency magnetic circuit in the critical local region (behind the pinna) while the overall transmitter size remains compact for spatial fit.
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 solution increases the inductance of the coil by 39% with a 50% reduction in weight, improves efficiency at low frequencies, and provides effective magnetic and electrical shielding, extending battery life and ensuring reliable communication.
Implementation Method 1
Incorporating a plate of magnetic material behind the coil to improve efficiency
Implementation Method 2
provide effective magnetic and electrical shielding
Implementation Method 3
provide effective magnetic and electrical shielding
Data Source
Figure 1A~2B
Figure 3A~4B
Figure 5~7
AI summary
A magnetic field transmitter, especially a transmitter used in conjunction with wireless communications earplugs. In one embodiment, a plate of magnetic material is used behind a coil of electrical conductor to improve the efficiency of the transmitter and to provide electrical and magnetic shielding. The specific dimensions and characteristics of the preferred embodiment of the transmitter described herein provide for efficient wireless communications.