Electroacoustic Transducer Using Pressurized Airflow
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Solution Overview
Problem
Conventional audio speakers are inefficient in converting electrical energy into audio energy, with cone speakers converting less than 10% and thermoacoustic speakers converting under 1%, and they are bulky due to mechanical resonance and large enclosures.
Innovation Solution
An array of electrically conductive membrane transducers, such as polyester-metal membrane pumps, that use pressurized airflow to generate sound, with a high resistance membrane charged by DC voltage and AC voltages applied to stators to ensure linear motion and increased audio power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional cone speakers are used, then sound can be produced through mechanical motion, but efficiency of converting electrical energy into audio energy is less than 10%
Solution Approach 1:
The patent replaces the conventional mechanical cone speaker system with an electrostatic transducer system that uses electric fields to directly move a membrane, eliminating the need for electromagnetic coils and mechanical resonance mechanisms. This substitution achieves higher conversion efficiency by directly coupling electrical energy to mechanical motion through electrostatic forces.
Solution Approach 2:
The patent changes the operating parameters by using high voltage DC bias with AC modulation to create time-varying electrostatic forces on the membrane. This parameter change enables more efficient energy transfer from electrical to acoustic domain compared to conventional low-voltage electromagnetic systems.
2Volume of moving object
If conventional cone speakers are used, then sound can be produced, but large enclosures are needed to muffle backside sound radiation
Solution Approach 1:
The patent extracts and eliminates the need for large enclosing chambers by using a planar membrane configuration where the backside radiation can be managed through the structure itself. The membrane can be mounted in an infinite baffle or the backside can be open, removing the requirement for bulky enclosure volumes.
Solution Approach 2:
The patent transitions from the conventional three-dimensional cone structure to a two-dimensional planar membrane structure. This dimensional change allows the speaker to achieve sufficient acoustic performance without requiring large enclosing volumes, as the planar configuration inherently manages sound radiation differently than conical structures.
3Volume of moving object
If thermoacoustic speakers are used, then large enclosures are not needed, but efficiency of converting electrical input into audio waves is under 1%
Solution Approach 1:
The patent replaces the thermal conversion mechanism of thermoacoustic speakers with direct electrostatic mechanical actuation. Instead of heating air to produce sound waves, the electrostatic transducer uses electric fields to directly move the membrane, achieving both compact form factor and high conversion efficiency simultaneously.
4Adaptability or versatility
If cone speakers depend on mechanical resonance, then frequency response is limited, but this limits the ability of woofers and tweeters to efficiently produce different frequency ranges
Solution Approach 1:
The patent employs a dynamically controllable electrostatic field that can respond across a wide frequency range without being constrained by mechanical resonance frequencies. The membrane and electrostatic structure can efficiently operate from low frequencies (including sub-20Hz) to high frequencies, eliminating the need for separate woofer and tweeter components with fixed resonance characteristics.
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 achieves higher audio power efficiency and compactness by ensuring linear motion of the membrane, allowing for higher frequency operation and increased sound power without the need for large enclosures, with audio output linearly proportional to electrical input, reducing distortion and enhancing sound quality.
Implementation Method 1
an electrically conductive membrane transducer that uses electrostatic forces to move the membrane
Implementation Method 2
with a high resistance membrane charged by DC voltage and AC voltages applied to stators to ensure linear motion and increased audio power
Data Source
AI summary
An improved compact electroacoustic transducer and loudspeaker system. The electroacoustic transducer (or array of electroacoustic transducers) can generate the desired sound by the use of pressurized airflow. The electroacoustic transducer uses a shared stator with an array of vent support fingers and metal frame instead of two stators per electroacoustic transducer.