Ultrasonic Phased Array for Targeted Mid-Air Audio
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Solution Overview
Problem
Conventional parametric speakers struggle to direct audio to specific individuals efficiently, as they require impractical installations and high power consumption, and fail to seamlessly deliver audio to moving targets.
Innovation Solution
A bodiless mid-air sound source system that focuses an acoustic field at arbitrary points in space using ultrasonic phased arrays, where ultrasonic carrier signals are modulated with audio signals and phase delay values are calculated to generate audible sound at precise focal points, allowing for targeted audio delivery and movement of sound sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional parametric speakers are installed overhead in the ceiling to direct audio to specific individuals, then audio directionality is improved, but installation complexity and power consumption increase significantly
Solution Approach 1:
The system divides the audio transmission task into multiple segments by using multiple ultrasonic transducers arranged in an array. Each transducer contributes to forming the acoustic beam through independent phase and amplitude control, enabling flexible spatial positioning without requiring ceiling installations.
Solution Approach 2:
The patent implements dynamic beam steering by independently controlling the phase and amplitude of each ultrasonic transducer. This allows the acoustic beam to be dynamically directed toward moving targets in real-time, eliminating the need for fixed ceiling installations and improving adaptability.
2Ease of operation
If conventional parametric speakers use a collimated ultrasonic beam to generate audible sound, then audio directionality is improved, but the ability to track moving individuals deteriorates
Solution Approach 1:
The system dynamically adjusts the phase and amplitude of each ultrasonic transducer based on the target's position. This enables real-time beam steering to track moving individuals, transforming the static collimated beam into a dynamic, adaptable acoustic field that follows target movement.
Solution Approach 2:
The patent employs feedback mechanisms to continuously monitor target position and adjust the ultrasonic transducer array configuration accordingly. This closed-loop control enables the system to adapt to moving targets and maintain optimal audio delivery throughout the target's movement.
3Power
If conventional parametric speakers project modulated carrier signals through the air, then audible sound is generated along the beam path, but power consumption increases significantly
Solution Approach 1:
The system concentrates ultrasonic energy locally at the desired target position by controlling the phase and amplitude distribution across the transducer array. This localized energy concentration creates the acoustic beam only where needed, reducing overall power consumption compared to projecting beams along extended paths.
Solution Approach 2:
The patent optimizes power efficiency by dynamically adjusting the frequency, phase, and amplitude parameters of the ultrasonic signals. By tuning these parameters to match the target position and acoustic field requirements, the system generates audible sound with minimized power consumption.
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
Enables the creation of a directed audio experience that can be precisely targeted at individuals or objects, with the ability to change the spatial position of sound sources, reducing power consumption and improving audio delivery to moving targets.
Implementation Method 1
Ultrasound can be modulated to generate audible sound in air based on a well-known phenomenon that is referred to as the nonlinear interaction of sound waves or the scattering of sound by sound. The nonlinearity of air provides for a self-demodulation effect.
Implementation Method 2
The nonlinearity of air provides for a self-demodulation effect. Ultrasound waves can be modulated by an audio signal and radiated from a transducer array into the air as primary waves. The modulated ultrasound waves interact in a nonlinear fashion in air. As a result, they are demodulated and produce the audio signal used to modulate the ultrasound waves.
Data Source
AI summary
A novel system and method for spatial sound generation is disclosed. A system and method for generating bodiless mid-air speakers includes the steps of: generating a modulated signal by modulating an ultrasonic carrier signal with an audio signal, determining a phase delay value for each ultrasonic transducer of an array of ultrasonic transducers with respect to one or more focal points, and driving each such ultrasonic transducer with the modulated signal in accordance with the phase delay value determined for each ultrasonic transducer to generate audible sound at the one or more focal points.