Membrane Pair Sound Device for Full-Audio Coverage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional speaker designs face challenges in producing high-fidelity sound across the full range of human audible frequencies due to the need for multiple drivers and enclosures, which increases size and cost, and existing ultrasonic pulse array systems require durable valves that can operate at extremely high speeds and endure harsh environments.
Innovation Solution
A sound producing device utilizing a membrane pair driven by a unipolar signal, generating air pulses at a frequency higher than the maximum human audible frequency, which enhances sound pressure level (SPL) and signal-to-noise ratio (SNR) performance, and employs a thin film actuator or nanoscopic electrostatic drive to produce aperiodic air pulses with non-zero offset, reducing the need for complex enclosures and improving area efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional speaker drivers are used to cover full audible frequency range, then sound coverage is improved, but device size and complexity increase due to multiple drivers
Solution Approach 1:
The patent applies a single membrane driver that can operate across the full audible frequency range (20 Hz to 20 kHz) by utilizing different operating modes: low-frequency sound waves cause membrane displacement while high-frequency sound waves cause membrane acceleration, eliminating the need for separate tweeters, mid-range drivers, and woofers
Solution Approach 2:
The patent changes the operating parameters of a single membrane driver to achieve full frequency coverage. By controlling the driving voltage and operating conditions, the membrane can be made to respond differently to various frequencies - displacing for low frequencies and accelerating for high frequencies - thus one component performs multiple functions
2Reliability
If speaker enclosure is added to improve low-frequency response, then sound quality is improved, but device size increases
Solution Approach 1:
The patent extracts and eliminates the traditional speaker enclosure by using ultrasonic air pulse generation. The ultrasonic vibrations create acoustic radiation pressure that directly drives air molecules to produce audible sound waves without requiring an enclosed box structure, thereby removing the volume constraint while maintaining low-frequency response capability
Solution Approach 2:
The patent replaces the mechanical enclosure system with an ultrasonic vibration system. Instead of using a physical box to resonate and amplify low frequencies, ultrasonic transducers generate high-frequency vibrations that create acoustic pressure waves in the air, which then produce audible sound including low-frequency components through nonlinear acoustic effects
3Power
If ultrasonic pulse rate is increased above maximum audible frequency, then sound pressure level is improved, but valve durability requirements increase
Solution Approach 1:
The patent replaces the mechanical valve system with an electrostatic or electromagnetic membrane actuation system. The membrane is directly driven by high-frequency voltage signals to vibrate at ultrasonic rates, eliminating mechanical valves and their associated durability issues while achieving high sound pressure levels through direct air coupling
Solution Approach 2:
The patent uses a flexible thin film membrane as the ultrasonic actuator. This membrane can be driven at ultrasonic frequencies by applying voltage across it, causing it to vibrate and directly couple with air molecules to generate high-frequency air pulses. The thin film structure allows rapid response at ultrasonic rates without the mechanical complexity and durability issues of valve systems
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 significant enhancement in sound pressure level, particularly at low frequencies, with improved SNR and reduced harmonic distortion, while minimizing the size and complexity of the sound producing device, and extends the lifespan of the device by reducing stress on the membranes.
Implementation Method 1
when a driving voltage is applied on the membrane pair, the first membrane and the second membrane deform toward each other
Implementation Method 2
air between the first membrane and the second membrane is squeezed outward and an air pulse is generated
Data Source
AI summary
A sound producing device is provided. The sound producing device comprises a substrate; and a membrane pair, disposed on the substrate, comprising a first membrane and a second membrane; wherein when a driving voltage is applied on the membrane pair, the first membrane and the second membrane deform toward each other, such that air between the first membrane and the second membrane is squeezed outward and an air pulse is generated toward a direction away from the substrate.