Piezoelectric Bone Conduction Receiver Phase Control
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Solution Overview
Problem
Traditional moving coil receivers in smartphones are difficult to miniaturize due to their complex structure and air vibration requirements, leading to inconsistent appearance and potential dust or moisture issues, while existing piezoelectric bone conduction devices have insufficient low-frequency sound reproduction and high mechanical quality factors that affect sound quality.
Innovation Solution
A piezoelectric bone conduction receiver with a driving signal switching module that controls the phases of driving signals to two independent piezoelectric driving modules, allowing for enhanced sound transmission through bone conduction in quiet environments and reduced noise leakage in noisy environments, using piezoelectric ceramic or organic polymer materials with flexible circuits and electrode layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional moving coil receiver is used, then air conduction sound transmission is achieved, but device size and thickness cannot be reduced
Solution Approach 1:
The patent replaces the traditional electromagnetic moving coil system with a piezoelectric bone conduction system. The piezoelectric element converts electrical signals directly into mechanical vibrations that travel through the bone to the inner ear, eliminating the need for complex electromagnetic components, magnets, and air conduction pathways, thereby achieving miniaturization while reducing structural complexity
Solution Approach 2:
The patent introduces bone conduction as an intermediary transmission path between the sound source and the ear. Instead of transmitting sound through air (requiring openings and membranes), the vibrations are transmitted directly through the bone, allowing for a more compact design without the need for traditional air conduction structures
2Reliability
If traditional moving coil receiver with air vibration conduction is used, then sound transmission is achieved, but appearance consistency is compromised and dust or moisture permeation risk increases
Solution Approach 1:
The patent eliminates the air conduction pathway by using bone conduction. The piezoelectric element generates vibrations that are transmitted directly through the bone to the inner ear, removing the need for openings in the device housing. This completely seals the device against dust and moisture while maintaining sound transmission functionality
Solution Approach 2:
The patent extracts and removes the air conduction function from the receiver design. By taking out the traditional air vibration conduction pathway (membrane, opening, air gap) and replacing it with direct bone conduction, the design achieves a sealed structure that is inherently protected against environmental contaminants
3Object-affected harmful factors
If air-conduction receiver is used in quiet environment, then local sound pressure level is high (90-100 dB), but sound leaks to surrounding area causing privacy leakage
Solution Approach 1:
The patent replaces air conduction with bone conduction to transmit sound. The piezoelectric element generates vibrations that travel through the bone directly to the inner ear, bypassing the air conduction pathway. This eliminates sound radiation into the surrounding environment, preventing privacy leakage while maintaining clear audio transmission for the user
Solution Approach 2:
The patent converts the potential harm of high sound pressure levels (which cause privacy leakage) into a benefit by using bone conduction. The vibrations are confined to the bone pathway and do not radiate into the air, transforming what would be a privacy violation into a secure private communication channel
4Volume of moving object
If piezoelectric bone conduction device is used, then device size is reduced, but low-frequency sound reproduction is insufficient
Solution Approach 1:
The patent employs a composite structure combining piezoelectric material with a metal plate. The piezoelectric element generates vibrations that are transferred to the metal plate, which then transmits them through the bone. This composite approach enhances the vibration output and low-frequency response while maintaining the compact size advantage of piezoelectric bone conduction
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 improved call privacy by minimizing sound perception through air coupling in quiet environments and maintaining high sound quality with increased volume in noisy environments, while being compact and resistant to dust and moisture.
Implementation Method 1
When piezoelectric crystals or piezoelectric materials are deformed by an applied external force, electrical charges which are variable depending upon the state of the applied external force are accumulated on outer surfaces of the piezoelectric crystals or the piezoelectric materials, thereby causing the piezoelectric crystals or the piezoelectric materials to exhibit the direct piezoelectric effect. When an external electric field is applied to piezoelectric crystals or piezoelectric materials, the piezoelectric crystals or the piezoelectric materials are mechanically deformed
Data Source
AI summary
A piezoelectric bone conduction receiver and a portable electronic device are disclosed. The piezoelectric bone conduction receiver comprises: a piezoelectric bone conduction receiver driving unit functioning as an acoustic vibration element, a piezoelectric driving and signal processing circuit connected with the piezoelectric bone conduction receiver driving unit, and a driving signal switching module, wherein the piezoelectric bone conduction receiver driving unit comprises at least two piezoelectric bone conduction receiver driving modules which can be independently driven in operation, the at least two piezoelectric bone conduction receiver driving modules are connected to the driving signal switching module which is connected with the piezoelectric driving and signal processing circuit, and the driving signal switching module is configured to control phases of piezoelectric driving signals output by the piezoelectric driving and signal processing circuit to the piezoelectric bone conduction receiver driving modules, so that the phases of the piezoelectric driving signals received by the piezoelectric bone conduction receiver driving modules are same or opposite.