Ultrasonic Membrane-Shutter Speaker for Low-Noise Audio Output
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Solution Overview
Problem
Existing picospeaker technologies face challenges in achieving optimal performance in terms of noise, dynamic range, harmonic distortion, and latency, with excessive power consumption being a concern for certain applications.
Innovation Solution
A speaker device comprising a membrane and shutter configuration, driven by a driver device that supplies electrical signals to generate ultrasonic and audio signals, utilizing a semiconductor integrated circuit with a charge pump and switching unit to modulate and demodulate signals, allowing asynchronous or synchronous operation of the membrane and shutter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If state of the art picospeaker approaches are used, then audio signal generation is achieved, but noise, dynamic range, harmonic distortion, and latency performance are insufficient
Solution Approach 1:
The system divides the audio signal generation into two distinct functional segments: a membrane that generates ultrasonic acoustic signals and a shutter that modulates these signals to produce audible audio. This segmentation allows each component to be optimized independently for its specific function, improving overall audio quality while managing complexity through functional separation.
Solution Approach 2:
The ultrasonic acoustic signal acts as an intermediary carrier that is modulated by the shutter to convey the actual audio information. This intermediary approach enables high-fidelity audio transmission by using the ultrasonic signal as a high-frequency carrier, similar to how radio waves carry audio in traditional radio transmission.
2Reliability
If circuitry is designed to provide required audio performance, then noise and distortion are reduced, but power draw becomes prohibitive
Solution Approach 1:
The system replaces traditional electroacoustic transduction with a mechanical acoustic modulation approach. Instead of using a single complex electromechanical transducer, the invention uses two simpler mechanical elements (membrane and shutter) that interact acoustically to produce the final audio signal, reducing the electrical power requirements while maintaining audio quality.
Solution Approach 2:
The shutter operates by periodically opening and closing to modulate the ultrasonic acoustic signal, creating the audible audio waveform through rhythmic interruption. This periodic mechanical action is more energy-efficient than continuous electrical drive, as the shutter only requires brief impulses to create each audio cycle rather than sustained electrical power.
3Adaptability or versatility
If membrane and shutter operate independently, then design flexibility is increased, but synchronization control becomes more difficult
Solution Approach 1:
The driver device is designed with multi-functionality to handle both independent and synchronized operation modes. It can generate separate drive signals for the membrane and shutter when independent operation is desired, or generate coordinated signals when synchronization is required, providing operational flexibility without requiring multiple specialized control circuits.
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 enhances performance by reducing noise and power consumption while maintaining high dynamic range and low latency, effectively generating high-quality audio signals.
Implementation Method 1
The membrane is positioned in a first plane and configured to oscillate along a first directional path and at a first frequency effective to generate an ultrasonic acoustic signal
Implementation Method 2
The shutter is configured to modulate the ultrasonic acoustic signal such that an audio signal is generated. The resulting modulated ultrasound signal has a lower acoustic frequency sideband which corresponds to the frequency difference between the frequency of the ultrasound acoustic beam and the modulation frequency
Data Source
AI summary
Techniques described herein generally relate to generating an audio signal with a speaker. In some examples, a speaker device is described that includes a membrane and a shutter and driver device is configured to receive an audio signal, modulate it and generate electric signals to operate the speaker and generate an acoustic audio signal.