Electrostatic Sound Generator Transformer Assembly
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Solution Overview
Problem
Electrostatic sound generators require high voltages, which are typically provided using expensive amplifiers or space-consuming transformers, and suffer from second-order distortion due to varying forces between the diaphragm and single back plate, especially when operating away from their resonance frequency.
Innovation Solution
A miniature assembly comprising a transformer and an electrostatic sound generator with a diaphragm and back plate, where the transformer has a winding ratio lower than 1:5000, allowing operation near the resonance frequency of 1-14 kHz, reducing power and voltage requirements, and minimizing transformer size, while the sound generator is driven electrostatically to minimize distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If high voltage amplifiers or transformers are used to provide high voltages for electrostatic sound generators, then the required voltage is achieved, but the device becomes expensive and space-consuming
Solution Approach 1:
The patent changes the operating parameters of the electrostatic sound generator by tuning its resonance frequency to match the audio signal frequency range. This resonance operation allows the generator to achieve high sound pressure levels with much lower voltage requirements, eliminating the need for bulky high-voltage transformers and amplifiers
Solution Approach 2:
The patent exploits mechanical resonance of the diaphragm system. By designing the diaphragm and backplate structure to have a natural resonance frequency within the audible range, the system amplifies sound output through resonant vibration, reducing the electrical power and voltage needed to drive the transducer
2Device complexity
If single back plate configuration is used in electrostatic sound generators, then the structure is simplified, but second order distortion increases due to varying forces between diaphragm and back plate
Solution Approach 1:
The patent uses resonance operation to counteract the non-linear force variations. When the diaphragm operates at its resonance frequency, the inertial forces and stiffness forces balance out the electrostatic force non-linearities, significantly reducing second-order distortion despite the simple single backplate configuration
Solution Approach 2:
The patent makes the system dynamically operate at resonance by tuning the mechanical properties of the diaphragm and backplate. This dynamic operation allows the system to maintain linear performance despite the static simplicity of the single backplate structure
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 configuration achieves efficient sound generation with reduced power and transformer size, minimizing distortion by operating the sound generator near its resonance frequency, resulting in high sound pressure levels with lower voltage requirements and improved efficiency.
Implementation Method 1
the transformer having a first conductor and a second conductor, the second conductor being connected to the signal generator, the first conductor having a first number of windings and the second conductor having a second number of windings
Implementation Method 2
Electrostatic sound generators usually operate on the basis of a high voltage difference between two back plates between which a diaphragm is fed the audio signal making, the diaphragm moves in accordance with the signal
Implementation Method 3
the diaphragm has a resonance frequency in the interval of 1-14 kHz... driving the sound generator close to or at its resonance frequency
Data Source
AI summary
An assembly of a transformer and an electrostatic sound generator is especially efficient if the resonance frequency of the diaphragm is in the frequency range in which the generator is operated, such as in the interval of 1-20 kHz. Then, a smaller transformer with a winding ratio of 5000 or less may be used for feeding the sound generator, making the assembly suitable for hearing aid purposes or in-ear products such as for pro audio use.