Variable-Length Distributed Mode Actuator for Wider DML Frequency Range
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Solution Overview
Problem
Distributed mode loudspeakers (DMLs) face limitations in generating a wide range of frequencies, which affects their ability to accurately reproduce sounds, particularly in varying output modes and volumes.
Innovation Solution
The DML adjusts the length of its cantilevered portion by changing the length of the supported portion of the distributed mode actuator, using a frequency selection module to determine the optimal fundamental frequency based on output mode, content type, and volume, allowing for dynamic frequency selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the DML uses a fixed-length distributed mode actuator, then the structure is simple and reliable, but the frequency range is limited
Solution Approach 1:
The patent implements a dynamically adjustable actuator length mechanism where the supported portion length can be changed based on desired frequency range. The actuator transitions from a fixed structure to a variable structure, allowing the cantilevered portion length to be adjusted to achieve different fundamental frequencies and expand the operable frequency range beyond what a single fixed-length actuator could provide.
Solution Approach 2:
The actuator is divided into two distinct segments: a supported portion and a cantilevered portion. This segmentation allows independent control of each segment's length, enabling precise adjustment of the cantilevered portion length to achieve desired frequency characteristics while maintaining structural integrity through the supported portion.
2Adaptability or versatility
If the DML adjusts the supported portion length to change frequency, then the frequency range expands, but the device complexity increases
Solution Approach 1:
The patent changes the physical parameter of the supported portion length to achieve frequency selection. By adjusting this geometric parameter, the system achieves different fundamental frequencies for the actuator, allowing frequency adaptation without changing the basic actuator design or adding complex frequency-tuning mechanisms.
Solution Approach 2:
The adjustable support structure serves multiple functions: it provides mechanical support for the actuator, enables frequency range selection, and allows adaptation to different operating conditions (handheld vs. hands-free modes). This multi-functionality reduces the need for separate components for each function, thereby limiting the increase in overall device complexity.
3Adaptability or versatility
If the DML uses a longer cantilevered portion for low frequencies, then low frequency reproduction improves, but the fundamental frequency decreases
Solution Approach 1:
The system dynamically adjusts the cantilevered portion length based on the desired frequency range. For low frequency reproduction, the cantilevered portion is extended to increase compliance and enable low frequency operation. For higher frequencies, the cantilevered portion is shortened to increase the fundamental frequency. This dynamic adjustment resolves the contradiction by making the length a variable parameter rather than a fixed constraint.
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 DMLs to generate sounds in a wider range of frequencies, improving sound reproduction accuracy and volume, particularly in hands-free and receiver modes.
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
Data Source
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 a distributed mode loudspeaker comprising an actuator that includes: a supported portion, and a cantilevered portion having a length, a first fundamental frequency, and adapted to create a force to cause vibration of a load to generate sound waves using the first fundamental frequency; a support element connected to the supported portion of the actuator and adapted to adjust, based on a change to a shape of the support element, a size of the length of the cantilevered portion to change the first fundamental frequency to a second fundamental frequency with which the load will generate sound waves; and a frequency selection module that provides a signal to the support element to cause the support element to change shape.