Piezoelectric Cantilever Loudspeaker for Flat Frequency Response
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Solution Overview
Problem
Piezoelectric loudspeakers exhibit poor acoustic performance due to superimposed vibration modes of multiple piezoelectric plates resulting in a frequency response curve with numerous peaks and valleys.
Innovation Solution
The loudspeaker design incorporates first and second piezoelectric cantilevers with different lengths in perpendicular directions, connected to diaphragms via connecting and support members, to stagger frequency points and reduce peak interference, ensuring a flat frequency response curve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two piezoelectric plates and two diaphragms are disposed in one-to-one correspondence to improve acoustic performance, then the loudspeaker can produce sound with better performance, but the frequency response curve will have a large number of peaks and valleys due to superimposed vibration modes
Solution Approach 1:
The patent applies asymmetry by making the first piezoelectric cantilever and second piezoelectric cantilever have different lengths in the second direction. This length difference causes the vibration modes of the two cantilevers to have different frequency characteristics, preventing the superposition that creates peaks and valleys in the frequency response curve, thereby achieving a flatter frequency response while maintaining good acoustic performance
Solution Approach 2:
The patent applies local quality by making the connecting member have different stiffness characteristics in different directions. The connecting member has smaller stiffness in the first direction (vertical vibration direction) and larger stiffness in the second direction (horizontal direction), which controls the vibration characteristics of the diaphragm assembly and contributes to flattening the frequency response curve
2Power
If piezoelectric plates are used to drive diaphragms to vibrate, then the loudspeaker can produce sound, but the piezoelectric plate itself has various vibration modes that cause poor acoustic performance
Solution Approach 1:
The patent segments the piezoelectric plate into a first piezoelectric cantilever and a second piezoelectric cantilever with different lengths. This segmentation divides the vibration modes into distinct frequency ranges, preventing the superposition of similar modes and reducing the peaks and valleys in the frequency response curve, thereby improving acoustic performance while maintaining sound production capability
Solution Approach 2:
The patent changes the physical parameters of the piezoelectric cantilevers by making them have different lengths in the second direction. This parameter change alters the natural frequency characteristics of each cantilever, ensuring their vibration modes do not superimpose, which flattens the frequency response curve and improves acoustic performance
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 design achieves a flat frequency response curve and improved acoustic performance with reduced peak interference, enhancing sensitivity and reliability while prolonging the service life of the loudspeaker.
Implementation Method 1
The piezoelectric plate vibrates under a drive voltage to drive the diaphragm to vibrate
Data Source
AI summary
A loudspeaker includes a support frame, a first diaphragm assembly, a second diaphragm assembly, a first vibration assembly, and a second vibration assembly; the first vibration assembly includes a first piezoelectric cantilever, the first piezoelectric cantilever includes a first fixed end connected to the support frame and a first free end suspended inside the support frame and connected to the first diaphragm assembly; the second vibration assembly includes a second piezoelectric cantilever, the second piezoelectric cantilever includes a second fixed end connected to the support frame and a second free end suspended inside the support frame and connected to the second diaphragm assembly; the first piezoelectric cantilever and the second piezoelectric cantilever are disposed opposite each other in a first direction, and the length of the first piezoelectric cantilever is different from the length of the second piezoelectric cantilever in the second direction perpendicular to the first direction.