Dual Winding Coil Bobbin for Acoustic Impedance Control
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Solution Overview
Problem
Conventional acoustic devices with single coils in hearing aids and similar devices face limitations in achieving optimal sound pressure levels and impedance due to fixed magnetic field strengths, which restrict their ability to produce varying sound pressure levels across different frequencies effectively.
Innovation Solution
The use of two coils with different windings wrapped around a bobbin, where one coil is coupled with a reactive circuit element, either in series or parallel, to modulate the magnetic field and enhance sound pressure levels and impedance characteristics, allowing for improved acoustic output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single coil with fixed windings is used, then the device structure is simple, but the sound pressure level and impedance cannot be optimized across different frequencies
Solution Approach 1:
The single coil is divided into two separate coils with different winding configurations. The first coil has a first number of turns and the second coil has a second number of turns, allowing each coil to be optimized for different frequency ranges. This segmentation enables independent optimization of electrical characteristics for low-frequency and high-frequency performance.
Solution Approach 2:
Different portions of the coil system are given different properties - the first coil is designed with specific turn count for optimal low-frequency response, while the second coil is designed with different turn count for optimal high-frequency response. This local differentiation of coil properties allows frequency-specific optimization without requiring a completely complex multi-component system.
2Device complexity
If the magnetic field strength is kept fixed, then the coil design is simple, but the ability to produce varying sound pressure levels across frequencies is limited
Solution Approach 1:
The magnetic field strength is made dynamically adjustable by providing two different magnetic field strengths corresponding to the two coils. The system can switch between or combine these different magnetic field strengths depending on the operating frequency, enabling the magnetic field to adapt to different acoustic requirements rather than remaining fixed.
Solution Approach 2:
The magnetic field parameter is changed by selecting different coils with different numbers of turns. The first coil produces a first magnetic field strength optimized for certain frequencies, while the second coil produces a second magnetic field strength optimized for other frequencies. This parameter change allows the system to achieve varying sound pressure levels across the frequency spectrum.
3Manufacturing precision
If conventional single coil designs are used, then impedance matching is difficult, but adding multiple coils increases device complexity
Solution Approach 1:
The electrical impedance is optimized by selecting appropriate numbers of turns for each coil. The first coil is designed with a first number of turns to provide optimal impedance matching for low-frequency signals, while the second coil is designed with a second number of turns for optimal impedance matching for high-frequency signals. This parameter optimization enables better impedance matching across the full frequency range.
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 configuration achieves higher sound pressure levels and lower acoustic impedance compared to conventional designs, particularly in the frequency range of 200 Hz to 20 kHz, resulting in enhanced acoustic performance by varying the magnetic field strength through adjustable coil turns and reactive circuit placements.
Implementation Method 1
An acoustic receiver generally includes a motor and a coil to which an electrical excitation signal is applied. The coil is disposed about a portion of an armature (also known as a reed), a movable portion of which is disposed in equipoise between magnets... Application of the excitation or input signal to the receiver coil modulates the magnetic field, causing deflection of the reed between the magnets.
Data Source
AI summary
Two coils are wrapped in one of numerous different implementations. In one implementation, the two coils are wrapped about a portion of a bobbin that has at least three flanges. The first coil is disposed about a first portion of the bobbin between the first flange and the second flange, and a second coil is disposed about a second portion of the bobbin between the second flange and the third flange.