Orthogonal-Diaphragm Transducer for Miniature High-SPL Speakers
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Solution Overview
Problem
Miniaturized speakers based on electromechanical and magnetostrictive materials struggle to meet required sound pressure levels due to limitations in strain capabilities.
Innovation Solution
A loudspeaker unit with a planar diaphragm inside a closed-loop shell wall, divided into two acoustic chambers, and guided by acoustic pressure plates, allowing orthogonal diaphragm motion to enhance sound pressure while simplifying the structure and reducing effective vibrating mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional voice coil speakers are used, then sound pressure level can be achieved, but the device size becomes large and structure complex
Solution Approach 1:
The patent replaces the traditional voice coil electromagnetic actuation system with a piezoelectric or magnetostrictive material-based actuation system. This substitution enables miniaturization while maintaining sound pressure generation capability, as these materials can produce sufficient strain in compact form factors where voice coils would be too large.
Solution Approach 2:
The patent introduces a depth dimension (D) perpendicular to the traditional width (W) and length (L) dimensions. By utilizing this additional dimension for the actuator configuration, the design achieves compact footprint in the W-L plane while accommodating the actuation mechanism along the D axis, thereby reducing overall speaker size without sacrificing sound pressure output.
2Volume of moving object
If piezoelectric or magnetostrictive materials are used for miniaturization, then speaker size is reduced, but sound pressure level becomes insufficient
Solution Approach 1:
The patent employs a planar diaphragm that can dynamically change its vibration characteristics. The diaphragm is configured to vibrate in multiple modes (bending, twisting, pulsating) depending on the actuation frequency and amplitude, allowing the miniaturized speaker to optimize its sound radiation efficiency across different operating conditions and compensate for the smaller radiating surface area.
Solution Approach 2:
By configuring the actuator to apply force in the depth dimension (D) perpendicular to the diaphragm plane, the patent creates efficient coupling between the actuation mechanism and the diaphragm. This orthogonal arrangement maximizes the transfer of actuation energy to the diaphragm, enabling sufficient sound pressure generation from a compact volume.
3Volume of moving object
If miniaturized design is implemented, then speaker size is reduced, but mechanical stability deteriorates
Solution Approach 1:
The patent segments the speaker structure into functionally independent components: the planar diaphragm for sound radiation, the closed-loop shell wall for structural support and acoustic isolation, and the actuation system. This segmentation allows each component to be optimized for its specific function while contributing to overall mechanical stability, with the rigid shell wall providing a stable platform for the miniaturized actuator and diaphragm assembly.
Solution Approach 2:
The patent utilizes composite material structures, particularly in the diaphragm construction which may combine multiple layers or materials with different properties. This allows the thin diaphragm to maintain sufficient mechanical strength and stability while remaining lightweight and compact, and the closed-loop shell wall provides rigid structural support that enhances overall mechanical stability in the miniaturized design.
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 design achieves improved sound pressure levels and reduces audio distortion, enabling a miniaturized design with enhanced mechanical stability.
Implementation Method 1
the planar diaphragm is configured within the frame to move orthogonally with respect to a normal vector of sound pressure output
Implementation Method 2
The first acoustic pressure guiding plate closes one end port of the first acoustic chamber in the first direction, while the second acoustic pressure guiding plate closes the other end port of the second acoustic chamber in the first direction
Data Source
AI summary
A transducer element comprises an enclosure with a multi-walled frame, walls, and a planar diaphragm. The diaphragm is configured to generally move orthogonally with respect to the directly coupled pressure wave propagation, and it bisects the depth of the enclosure to form two independent acoustic chambers. The enclosure includes lids with ports, at least one port for each chamber. The lids are substantially perpendicular to the diaphragm and separated by the depth of the enclosure. The transducer element may be part of a transducer that utilizes multiple elements with similar designs to produce higher volume displacement, allowing for higher SPL output when used in loudspeaker applications. Additional planar diaphragms may also be present in each transducer element.