Distributed Mode Actuator Tuning for Wider Loudspeaker 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 volume conditions.
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 adjustment.
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 manufacturing is easy, but the frequency range is limited and sound reproduction accuracy deteriorates
Solution Approach 1:
The patent implements a dynamically adjustable actuator length mechanism where the supported portion length can be changed based on desired frequency requirements. 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 while maintaining structural integrity.
Solution Approach 2:
The patent changes the physical parameter of the actuator's supported portion length to achieve different operational characteristics. By varying this length parameter, the system can tune the fundamental frequency of the actuator to match different output modes (handheld vs. hands-free), thereby expanding the frequency range without requiring multiple different actuators.
2Measurement precision
If the DML adjusts the supported portion length dynamically, then the frequency range expands and sound reproduction accuracy improves, but the device complexity and control difficulty increase
Solution Approach 1:
The patent incorporates a feedback mechanism where the system detects the current output mode (handheld or hands-free) and automatically adjusts the supported portion length accordingly. This feedback loop ensures that the actuator is optimally configured for the current usage scenario, improving sound reproduction accuracy by matching the actuator's fundamental frequency to the requirements of the active output mode.
Solution Approach 2:
The patent performs preliminary adjustment of the supported portion length based on anticipated or detected usage conditions. By pre-configuring the actuator length before sound generation begins, the system ensures optimal performance for the intended output mode without requiring complex real-time adjustments during operation.
3Quantity of substance
If the DML uses a longer cantilevered portion for low frequency generation, then low frequency sound production is improved, but the device size and volume requirements increase
Solution Approach 1:
The patent uses a dynamic adjustment mechanism that allows the cantilevered portion length to be changed based on the desired sound output characteristics. For low frequency generation in hands-free mode, the system extends the cantilevered portion to achieve the necessary fundamental frequency, while for handheld mode or higher frequencies, it reduces the length to maintain a compact form factor. This dynamic capability allows the system to achieve large sound output volume without permanently increasing device size.
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, by dynamically selecting the fundamental frequency.
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 force creates vibrations of the display panel that couple to surrounding air to generate sound waves
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.