Piezoelectric Speaker in Battery Cover for Thin Mobile Audio
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Solution Overview
Problem
The challenge is to improve the sound quality of thin mobile terminals with limited speaker sound chamber space, where existing moving-coil speakers perform poorly due to size constraints.
Innovation Solution
A mobile terminal design that utilizes a multifunctional battery cover equipped with an ultra-thin piezoelectric ceramic speaker, which includes a processing module to identify and activate the battery cover for audio output, using a D-type or G-type amplifier to power amplify the audio signal for the thin speaker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a moving-coil speaker is used in a thin mobile terminal, then the terminal can achieve basic sound output function, but the sound quality is poor due to limited sound chamber space
Solution Approach 1:
The patent replaces the traditional moving-coil speaker with a piezoelectric ceramic speaker. The piezoelectric effect converts electrical signals directly to mechanical vibrations, eliminating the need for a large magnetic field structure and voice coil assembly. This substitution enables high-quality sound output in a extremely thin form factor (0.3mm thickness) without requiring a large sound chamber volume.
Solution Approach 2:
The patent changes the fundamental operating parameters of the speaker system by using piezoelectric ceramic material instead of electromagnetic coils. The piezoelectric ceramic speaker operates at much lower voltages (3.6V-5V) compared to traditional speakers, and achieves higher efficiency in converting electrical energy to acoustic energy. This parameter change enables excellent sound quality in a thin terminal with limited space.
2Length of moving object
If the terminal thickness is reduced to meet design requirements, then the terminal becomes thinner and more portable, but the space for speaker installation is severely limited
Solution Approach 1:
The patent employs an ultra-thin piezoelectric ceramic speaker with thickness of only 0.3mm, which can be integrated into the battery cover or back panel of the terminal. This thin-film approach allows the speaker to be installed in the limited space available in thin terminals without compromising the overall thickness design. The flexible integration method enables sound output functionality while maintaining the terminal's sleek, thin profile.
Solution Approach 2:
The patent relocates the speaker from the traditional front-facing position to the battery cover or back panel area, utilizing unused vertical space in the terminal structure. By placing the piezoelectric speaker in the battery cover, the design achieves sound output capability without increasing the terminal's front thickness, effectively using another dimension of available space.
3Use of energy by moving object
If a traditional speaker is installed in a thin terminal, then the terminal maintains basic audio functionality, but the electro-acoustic efficiency is low and power consumption is high
Solution Approach 1:
The patent replaces the electromagnetic conversion system with a piezoelectric conversion system. The piezoelectric ceramic speaker directly converts electrical energy to mechanical vibrations with much higher efficiency, reducing power consumption significantly. The direct conversion mechanism eliminates energy losses associated with magnetic field generation and coil resistance, achieving both low power consumption and high electro-acoustic efficiency simultaneously.
Solution Approach 2:
The patent changes the electrical operating parameters by using low-voltage (3.6V-5V) piezoelectric ceramic speakers that operate at higher efficiency points. The piezoelectric material's inherent high coupling coefficient enables efficient energy conversion at these lower voltages, achieving excellent electro-acoustic efficiency while consuming less power compared to traditional high-voltage speaker 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
This solution enhances sound quality without increasing the terminal's thickness, leveraging the high electro-acoustic efficiency and low power consumption of the ultra-thin piezoelectric ceramic speaker to meet the design requirements for thin mobile terminals.
Implementation Method 1
an ultra-thin piezoelectric ceramic speaker
Data Source
AI summary
A mobile terminal that sends out sound via a multifunctional battery cover and a method thereof. The mobile terminal includes a processing module that identifies a battery cover including a piezoelectric ceramic speaker based on an ID signal output by the battery cover and outputs an audio signal to the piezoelectric ceramic speaker.