Nanoscale Membrane Eardrum Transducer for Compact Hearing Aids
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Solution Overview
Problem
Current hearing aids face inefficiencies and battery life issues due to the need for a diaphragm/horn structure to couple acoustic energy into the ear, which increases bulk and reduces the effectiveness of compact designs, especially with small electric actuators and low voltages.
Innovation Solution
A nanoscale membrane is used to enhance eardrum stimulation through constructive interference of surface waves generated by a piezoelectric substrate, allowing for improved coupling and multipoint stimulation, with a lightweight and wireless transducer design that includes a piezoelectric substrate and interdigitated electrodes to induce surface acoustic waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diaphragm/horn structure is used to couple acoustic energy into the air, then the transducer can effectively transmit sound, but the bulk and weight of the transducer increases
Solution Approach 1:
The patent removes the traditional diaphragm/horn structure from the transducer design. Instead of using a separate acoustic coupling component, the invention directly applies the electric actuator to the eardrum, eliminating the unnecessary intermediate structures that added bulk and weight while not contributing to the core function of stimulating the eardrum.
Solution Approach 2:
The patent introduces a nanoscale membrane as an intermediary between the piezoelectric actuator and the eardrum. This ultra-thin membrane serves as the acoustic coupling interface, allowing effective energy transmission while adding minimal mass. The membrane acts as a mediator that bridges the electrical-to-mechanical conversion and the acoustic stimulation functions.
2Volume of moving object
If the transducer size is reduced to make hearing aids more compact, then the device becomes less obtrusive, but the ability to provide sufficient eardrum stimulation decreases
Solution Approach 1:
The patent changes the physical parameters of the actuator by using piezoelectric material that can generate sufficient mechanical displacement at very small scales. The nanoscale membrane further optimizes this by having extremely small thickness (nanometer scale), allowing the miniaturized transducer to maintain effective stimulation capability through optimized material properties and geometric parameters rather than relying on larger size.
Solution Approach 2:
The patent employs composite material strategies by combining piezoelectric substrate material with a nanoscale membrane material. This composite structure leverages the piezoelectric effect for efficient electrical-to-mechanical energy conversion while the nanoscale membrane provides optimal acoustic coupling properties, achieving high stimulation effectiveness in a compact form factor.
3Use of energy by moving object
If low voltage is used to drive the small electric actuator, then the hearing aid is safer and more energy-efficient, but the actuator cannot generate sufficient displacement to stimulate the eardrum effectively
Solution Approach 1:
The patent changes the material parameters by using piezoelectric materials with high coupling coefficients that can generate large mechanical displacements in response to small electrical voltages. The nanoscale membrane further enhances this effect by its ultra-thin geometry, which allows for greater flexibility and displacement amplitude at low actuation voltages, thereby maintaining energy efficiency while achieving sufficient stimulation.
Solution Approach 2:
The patent uses a nanoscale membrane (ultra-thin film) as the acoustic interface. This thin film structure is inherently more compliant and capable of achieving larger displacements for a given actuation force compared to thicker, stiffer materials. The nanoscale thickness allows the membrane to respond effectively to low-voltage actuation while still providing sufficient mechanical stimulation to the eardrum.
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 provides efficient and controlled stimulation of the eardrum, reducing the weight and bulk of the transducer while maintaining effective energy transfer, enabling a compact and energy-efficient hearing aid design.
Implementation Method 1
The piezoelectric substrate provides piezoelectric material distributed about an opening, and a set of interdigitated electrodes is attached to the piezoelectric substrate and configured to be electrically driven to induce surface acoustic waves
Implementation Method 2
induce surface acoustic waves around the opening converging on a point in the opening. A nanoscale membrane is supported on the inner surface of the piezoelectric substrate and acoustically couples to the piezoelectric substrate over the opening
Implementation Method 3
The nanoscale membrane boosts the displacement of the eardrum through the process of constructive interference of converging surface waves generated by the piezoelectric material
Data Source
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AI summary
A transducer supported by the eardrum provides a piezoelectric material exchanging energy with the eardrum through a nanoscale membrane, the latter serving to boost the coupling between the piezoelectric material and the eardrum