Ultrasonic Speaker Membrane and Shutter Modulation
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Solution Overview
Problem
Existing speaker technologies are limited in generating audio signals effectively using ultrasonic acoustic signals, as they lack efficient mechanisms to modulate these signals into audible frequencies.
Innovation Solution
A speaker device and array design that incorporates a membrane and shutter system, where the membrane oscillates at ultrasonic frequencies and the shutter modulates the signal to produce an audio signal, utilizing comb drive actuators and capacitive micromachined ultrasonic transducers to control the movement and alignment of the shutter relative to the membrane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional speaker designs are used, then audio signal generation is straightforward, but the device size and power consumption are excessive for compact mobile devices
Solution Approach 1:
The speaker device is segmented into functionally independent components: a ultrasonic transducer for generating high-frequency sound waves and a separate shutter assembly for modulating these waves into audible frequencies. This segmentation allows each component to be optimized independently, reducing overall device size while maintaining functionality.
Solution Approach 2:
The invention transitions from traditional direct audio frequency generation to an indirect approach using ultrasonic frequencies modulated by a shutter. This dimensional change in operating frequency enables miniaturization of the transducer while achieving the same audio output through frequency modulation rather than direct vibration.
2Volume of moving object
If ultrasonic frequencies are used for miniaturization, then device size is reduced, but the mechanism to modulate ultrasonic signals into audible frequencies becomes complex
Solution Approach 1:
The invention replaces complex electronic modulation circuits with a mechanical shutter system that physically opens and closes to modulate ultrasonic waves. This mechanical approach simplifies the overall system by eliminating the need for sophisticated signal processing electronics, reducing device complexity while enabling ultrasonic-to-audio conversion.
3Adaptability or versatility
If a shutter mechanism is added to modulate ultrasonic signals, then audio signal generation is enabled, but the device complexity increases
Solution Approach 1:
The shutter assembly serves multiple functions: it modulates ultrasonic waves into audible frequencies, provides acoustic sealing when closed, and can be integrated with the housing structure. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity while enabling audio signal generation.
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 generation of audio signals by modulating ultrasonic acoustic signals into audible frequencies, suitable for compact mobile devices, and allows for the creation of psychoacoustic effects and unique sound localization.
Implementation Method 1
The membrane is configured to oscillate at ultrasonic frequencies
Implementation Method 2
the shutter modulates the signal to produce an audio signal
Data Source
Figure 1A
Figure 1B
Figure 1C
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. The membrane can be configured to oscillate along a first directional path and at a first frequency effective to generate an ultrasonic acoustic signal. The shutter can be positioned about the membrane and configured to modulate the ultrasonic acoustic signal such that an audio signal can be generated.