MEMS Coil Module for Microspeaker Efficiency
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Solution Overview
Problem
Conventional speakers in smartphones consume a significant amount of battery power when used in hands-free mode, and existing microspeakers lack high efficiency and linearity, especially in both high and lower frequency regimes.
Innovation Solution
A MEMS coil module is developed, comprising a vibrating membrane suspended on an air chamber, a planar coil embedded in the membrane, and a soft magnet surrounding the coil. This module is designed to provide improved sound performance across both high and lower frequency ranges while maintaining a small size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional speaker is used in hands-free mode, then the audio system can provide sufficient sound output, but the battery power consumption increases significantly
Solution Approach 1:
The invention transitions from a conventional three-dimensional speaker structure to a two-dimensional planar coil configuration embedded in a flexible membrane. This dimensional change enables the speaker to achieve sufficient sound output power while dramatically reducing the overall size and material quantity, thereby lowering power consumption in hands-free mode
Solution Approach 2:
The invention employs a flexible membrane as the speaker diaphragm, replacing traditional rigid speaker structures. This thin film approach reduces the mass and volume of the moving components, enabling efficient power usage while maintaining adequate acoustic output for hands-free operation
2Volume of moving object
If existing microspeaker designs are used, then the device size is reduced, but the efficiency and linearity deteriorate, especially in high and lower frequency regimes
Solution Approach 1:
The invention implements a soft magnet layer with specific magnetic properties positioned strategically around the planar coil and embedded in the flexible membrane. This localized magnetic enhancement improves the efficiency and linearity of the microspeaker across different frequency ranges without increasing the overall device volume
Solution Approach 2:
The invention uses a composite structure combining a flexible membrane material with embedded soft magnet layers and planar coil traces. This composite approach maintains the compact size of the microspeaker while improving its electromagnetic performance, efficiency, and linearity response across the audio frequency spectrum
3Reliability
If the soft magnet layer is arranged surrounding the coil pattern, then the magnetic field distribution is improved, but the manufacturing complexity increases
Solution Approach 1:
The invention combines the soft magnet layer formation with the existing flexible membrane fabrication process. The soft magnet material is applied and patterned directly onto the flexible membrane during the same manufacturing sequence used to create the planar coil, merging multiple steps into one integrated process and reducing overall manufacturing complexity
Solution Approach 2:
The flexible membrane serves multiple functions simultaneously: it acts as the speaker diaphragm, provides the substrate for the planar coil, and hosts the soft magnet layer. This multi-functionality reduces the need for separate components and assembly steps, simplifying manufacturing while achieving improved magnetic field distribution
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 MEMS coil module achieves enhanced sound performance with improved efficiency and linearity across a wide frequency range, while maintaining a compact size, thus addressing the power consumption issues of conventional speakers.
Implementation Method 1
A MEMS coil module is developed, comprising a vibrating membrane suspended on an air chamber, a planar coil embedded in the membrane, and a soft magnet surrounding the coil
Implementation Method 2
a soft magnet, embedded in the vibrating membrane and disposed surrounding at least a portion of a contour of the planar coil
Data Source
AI summary
Disclosed is a coil module, comprising: a vibrating membrane suspended on an air chamber defined and supported by a first substrate, at least one planar coil, embedded in the vibrating membrane, and at least a soft magnet, embedded in the vibrating membrane and disposed surrounding at least a portion of a contour of the planar coil; wherein a substantial portion of the planar coil locates at substantially the same plane where a portion of the soft magnet is arranged.