Flat Panel Horn Loudspeaker with Distributed Mode Actuator
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Solution Overview
Problem
Conventional loudspeakers induce piston-like motion, whereas flat panel distributed mode loudspeakers struggle to effectively excite distributed vibrational modes in panels using electro-acoustic actuators, leading to inefficiencies in acoustic wave production.
Innovation Solution
Magnetic distributed mode actuators with electromagnetic coils attached to a flat panel and permanent magnets coupled to an inertial beam, allowing for vibrational modes to be excited and generating acoustic waves by interacting magnetic fields, with the inertial beam and panel vibrating to produce sound across a range of frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional electro-acoustic actuators are used to excite distributed vibrational modes in flat panel loudspeakers, then the device can produce sound, but the efficiency of acoustic wave production is poor
Solution Approach 1:
The actuator is segmented into two distinct components: electromagnetic coils attached to the flat panel and permanent magnets attached to the inertial beam. This segmentation allows each component to be optimized for its specific function, with the coils generating magnetic fields and the magnets providing concentrated magnetic flux, thereby improving the efficiency of acoustic wave production while reducing energy losses.
Solution Approach 2:
The patent transitions from conventional piston-like motion (one-dimensional) to distributed vibrational modes across the flat panel surface (two-dimensional). The inertial beam with attached magnets creates distributed excitation points across the panel, enabling efficient excitation of multiple vibrational modes simultaneously and significantly improving acoustic wave production efficiency.
2Productivity
If electromagnetic coils are attached directly to the flat panel and magnets to the inertial beam, then distributed vibrational modes can be effectively excited, but the device complexity increases
Solution Approach 1:
The inertial beam serves multiple functions: it provides mechanical coupling between the flat panel and the permanent magnets, acts as a structural support element, and enables the distribution of magnets across the panel surface. This multi-functionality reduces the need for additional separate components, thereby managing device complexity while achieving effective excitation of distributed vibrational modes.
Solution Approach 2:
The patent combines the inertial beam with the permanent magnet attachment system, merging structural support and magnetic excitation functions into a single integrated component. This consolidation simplifies the overall actuator structure compared to having separate mounting mechanisms, while still enabling effective distributed mode excitation.
3Ease of operation
If the inertial beam is made rigid and mechanically coupled at endpointsonly, then the panel and beam can vibrate freely, but the manufacturing precision required increases
Solution Approach 1:
The patent extracts the vibration constraints from the entire inertial beam by using endpoint couplings only, allowing the beam and panel to vibrate freely in between the coupling points. This extraction of constraints at critical locations maintains manufacturing simplicity while preserving vibration freedom, avoiding the need for precision constraints along the entire beam length.
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 efficient production of acoustic waves with minimal distortion, allowing the loudspeaker to operate effectively across a wide frequency range from 10 Hz to 22,000 Hz, with the ability to be integrated into various devices and surfaces.
Implementation Method 1
when the electrically-conducting coil is energized an interaction between the magnetic field of the magnet and magnetic field from the electrically-conducting coil applies a force sufficient to displace the member panel and inertial beam
Data Source
AI summary
A distributed mode actuator (DMA) includes a flat panel extending in a plane and a rigid member(s) extended parallel to the plane. The members are mechanically attached to or glued and/or embedded within the face of the flat panel. All associated members are free to vibrate perpendicular and horizontally to the plane. The DMA also includes a magnet and electrically-conducting coil. The coil and magnet are mechanically coupled to the member or associated member. When the coil is energized, an interaction between a magnetic field of the magnet and a magnetic field from the coil applies a force sufficient to generate vibrations and/or movement perpendicular and horizontally to the plane. The DMA also includes components embedded within and attached to the plane, and indentations within the plane, to facilitate acoustical and vibrational waves.