Distributed Mode Actuator With Tunable Fundamental Frequency
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Solution Overview
Problem
Distributed mode loudspeakers struggle to adjust their fundamental frequency dynamically, limiting their ability to generate a wide range of frequencies and accurately reproduce sounds based on output mode, content, and volume.
Innovation Solution
The loudspeaker adjusts the length of its cantilevered portion by changing the length of its supported portion, using a frequency selection module to send signals to a support element, which alters the shape and fundamental frequency of the actuator, allowing for dynamic frequency selection based on output mode, content, and volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the DML uses a fixed-length actuator, then the structure is simple and reliable, but the frequency range is limited
Solution Approach 1:
The patent implements a dynamically adjustable actuator where the supported portion length can be changed during operation. The actuator transitions from a static structure to a dynamic one that can adapt its configuration based on the desired frequency range, allowing the DML to switch between different fundamental frequencies by adjusting the supported portion length.
Solution Approach 2:
The patent changes the physical parameter of the actuator's supported portion length to achieve different frequency ranges. By varying this length parameter, the system can adjust the fundamental frequency of the actuator, enabling the DML to operate across a broader frequency spectrum without requiring multiple fixed actuators.
2Adaptability or versatility
If the DML changes the supported portion length to adjust frequency, then the frequency range expands, but the device complexity increases
Solution Approach 1:
The support structure is designed as a dynamic element that can change its configuration. Instead of using multiple fixed support structures for different frequencies, the patent employs a single support structure that can dynamically adjust its effective length to match the desired frequency range, reducing overall device complexity while maintaining frequency adaptability.
Solution Approach 2:
The support structure serves multiple functions: it provides mechanical support for the actuator, enables frequency adjustment by changing its effective length, and can be controlled by the frequency selection module. This multi-functionality reduces the need for separate components for each function, thereby managing device complexity.
3Adaptability or versatility
If the DML uses a longer cantilevered portion, then lower frequencies are generated, but the device size increases
Solution Approach 1:
Instead of having a permanently long cantilevered portion for low-frequency generation, the patent uses a dynamic configuration where the supported portion length can be extended when low frequencies are needed and retracted when high frequencies are required. This allows the device to achieve low-frequency capability without permanently increasing its size.
Solution Approach 2:
The support structure can be nested or folded when not in use, allowing the cantilevered portion to be extended only when low-frequency operation is required. When high-frequency operation is needed, the support structure is retracted, effectively nesting the extended portion back into a compact form, thus maintaining a small device size while providing access to both low and high frequency ranges.
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
This approach enables the loudspeaker to generate sounds in a wider range of frequencies and higher volumes, improving sound reproduction accuracy and quality.
Implementation Method 1
A DML may use a distributed mode actuator ('DMA'), e.g., a piezoelectric transducer, to cause the panel to vibrate and generate sound
Implementation Method 2
The support element may include an electroactive element and an adjustment support
Data Source
Figure 1A~1C
Figure 2
Figure 3A~3B
AI summary
Methods, systems, and apparatus, including computer programs encoded on computer storage media, for changing a distributed mode loudspeaker's fundamental frequency. One of the systems includes an actuator for a distributed mode loudspeaker that includes: a first portion having (i) a first end adapted to contact, across an area, an adjustable-shape support element, and (ii) a first length that, during operation of the actuator, changes in dimension to cause a change in size of the area in response to a change in the shape of the adjustable-shape support element, and a cantilevered portion (a) adapted to create, during operation of the actuator, a force to cause vibration of a load and (b) having a second length that, based on a change to the dimension of the first length and the size of the area, changes in dimension and a fundamental frequency at which the load will generate sound waves.