Magnetostrictive Microloudspeaker Actuator Design
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Solution Overview
Problem
Conventional acoustic actuators for hearing aids require larger dimensions, lower sound levels, and higher power consumption, making them inefficient and not suitable for miniaturized applications.
Innovation Solution
A miniaturized acoustic actuator with a self-supporting structure connected by suspensions, incorporating a magnetostrictive layer and a magnetic field generator, utilizing a solenoid or torroidal coil, and optimized layer thicknesses to achieve high sound levels with low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional electromagnetic acoustic actuators are used, then they can generate sound in the audible range, but their dimensions are large and power consumption is high
Solution Approach 1:
The patent replaces the conventional electromagnetic actuation system with a magnetostrictive system. The magnetostrictive layer directly converts magnetic field energy into mechanical deformation, eliminating the need for traditional electromagnetic coils and magnetic circuits, thereby significantly reducing actuator dimensions and power consumption while maintaining audible sound generation
Solution Approach 2:
The patent changes the fundamental actuation mechanism from electromagnetic to magnetostrictive, utilizing the magnetostrictive effect where material dimensions change in response to magnetic field variations. This parameter change enables compact design with low power consumption while achieving high sound pressure levels in the audible range
2Illumination intensity
If the magnetostrictive layer thickness is increased to improve sound level, then the mechanical stress in the structure increases
Solution Approach 1:
The patent optimizes the thickness parameter of the magnetostrictive layer to achieve the desired sound pressure level while keeping mechanical stress within acceptable limits. By precisely controlling the magnetostrictive layer thickness and applying magnetic anisotropy, the system achieves high sound output without excessive mechanical stress that would compromise structural integrity
Solution Approach 2:
The patent applies magnetic anisotropy to the magnetostrictive layer before or during operation to pre-establish favorable magnetic domain orientations. This preliminary magnetic field application optimizes the magnetostrictive response, enabling efficient conversion of magnetic energy to mechanical vibration at optimized layer thicknesses, thereby achieving high sound levels without requiring excessive thickness that would increase stress
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 enables a compact, high-sound-level acoustic actuator with reduced power consumption, suitable for hearing aids, by leveraging the magnetostrictive effect and magnetic anisotropy to minimize mechanical stresses and optimize energy efficiency.
Implementation Method 1
The way in which the loudspeaker works is based on the magnetostrictive effect, which results in a change in the dimensions or in the geometry of the self-supporting structure in an alternating magnetic field
Implementation Method 2
the means for generating a magnetic field is in the form of a solenoid coil (cylindrical coil), with the magnetostrictive layer forming the coil core
Data Source
AI summary
An acoustic actuator includes a support layer, in which a self-supporting structure is defined and connected to the support layer by at least two suspensions, at least one magnetostrictive layer which has been disposed on the support layer and is provided at least in part on the self-supporting structure, and a device for generating a magnetic field in the magnetostrictive layer. The way in which the loudspeaker works is based on the magnetostrictive effect, which results in a change in the dimensions of the self-supporting structure in an alternating magnetic field. This causes the self-supporting structure to oscillate. A method for producing an acoustic actuator is also provided.