Micro Speaker Magnet Structure for High SPL in Thin Profiles
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Solution Overview
Problem
Traditional moving coil speakers have a larger size and volume, and existing MEMS processes for manufacturing micro moving coil speakers do not adequately address the need for improved performance while reducing size.
Innovation Solution
A micro speaker structure with a novel magnet design featuring multiple polar areas and configurations, including cylindrical, ring, and integral magnet structures, enhances the magnetic field distribution and interaction with a multi-layered coil to increase sound pressure level (SPL) without increasing size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional moving coil speakers are used, then audio performance is maintained, but size and volume are larger
Solution Approach 1:
The magnet member is divided into multiple magnetic segments with different polarities (first polar area and second polar area with opposite polarities) arranged in specific patterns. This segmentation allows concentrated magnetic field distribution in the interaction region with the coil, achieving high SPL in a compact volume while maintaining audio performance
Solution Approach 2:
Different regions of the magnet member have different magnetic pole arrangements optimized for their specific functions. The central region has a first polarity while the peripheral region has the opposite polarity, creating localized magnetic field concentrations that maximize the magnetic interaction with the coil within the limited space, thereby maintaining audio performance in a reduced volume
2Power
If magnet member with multiple polar areas is used, then sound pressure level is increased, but magnetic field distribution complexity increases
Solution Approach 1:
The magnet member employs an asymmetric magnetic pole arrangement where the first polar area (central) and second polar area (peripheral) have different geometries and polarity configurations. This asymmetric design creates an optimized non-uniform magnetic field distribution that concentrates magnetic flux in the coil interaction region, maximizing sound pressure level while the systematic arrangement keeps the complexity manageable
Solution Approach 2:
The magnetic pole arrangement extends in multiple spatial dimensions with central and peripheral poles arranged in specific geometric patterns. This multi-dimensional configuration allows the magnetic field to be concentrated in three-dimensional space around the coil, achieving high SPL without requiring a larger overall magnet structure, thus balancing power output with controlled complexity
3Length of moving object
If MEMS process is used to manufacture micro moving coil speaker, then size is reduced, but performance improvement is insufficient
Solution Approach 1:
The magnet member is positioned within the hollow chamber of the substrate, and the coil is embedded within the diaphragm structure. This nested arrangement packs multiple functional components into a compact hierarchical structure, achieving minimal speaker size while the optimized magnetic pole configuration ensures sufficient magnetic interaction for acceptable performance
Solution Approach 2:
The invention changes the magnetic field distribution parameters by implementing specific polarity patterns (central first polarity, peripheral opposite polarity) and adjusting the strength and concentration of magnetic flux in the interaction region. These parameter optimizations compensate for the size reduction, maintaining adequate performance in the miniaturized MEMS speaker structure
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 novel magnet design increases sound pressure level by concentrating magnetic lines, reduces speaker thickness, and improves performance by enhancing magnetic field interaction, thus addressing the challenge of smaller size without compromising audio quality.
Implementation Method 1
The magnet member has a first side facing the coil and a second side opposite the first side, wherein the first side includes a first polar area and a second polar area having different polarities
Data Source
AI summary
A micro speaker structure is provided. The micro speaker structure includes a substrate, a diaphragm, a coil, a circuit board, and a magnet member. The substrate has a hollow space. The diaphragm is disposed over the substrate and covers the hollow chamber. The coil is embedded in the diaphragm. The circuit board is attached to the substrate. The magnet member is disposed on the circuit board and in the hollow chamber. The magnet member has a first side facing the coil and a second side opposite the first side, wherein the first side includes a first polar area and a second polar area having different polarities.