Piezoelectric Speaker Diaphragm Segmentation for Flat Frequency Response
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Solution Overview
Problem
Piezoelectric speakers used in headphones and earphones suffer from poor sound quality, particularly in strong magnetic fields, where traditional dynamic speakers cannot operate, and their non-magnetic nature limits their application in environments like MRI devices.
Innovation Solution
A speaker system comprising multiple speakers with diaphragms of different shapes and corresponding filters, designed to produce a flat frequency response by optimizing transfer characteristics, allowing for effective sound wave synthesis and noise reduction in strong magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If piezoelectric speakers are used in headphones and earphones, then they can operate in strong magnetic fields where dynamic speakers cannot be used, but the sound quality becomes poor
Solution Approach 1:
The patent divides the frequency response into multiple bands and assigns different diaphragm shapes to handle different frequency ranges. Multiple diaphragms with distinct geometries (circular, rectangular, triangular, etc.) are used to segment the audio spectrum, with each diaphragm optimized for its specific frequency band, thereby achieving good sound quality across all frequencies while maintaining compatibility with strong magnetic field environments
Solution Approach 2:
The patent employs diaphragms with asymmetric and irregular shapes rather than conventional symmetric circular shapes. By using diaphragms with varying geometries (rectangular, triangular, polygonal, and irregular forms), the system creates complementary transfer characteristics that when combined, produce a flat overall frequency response, thereby improving sound quality while maintaining the advantage of operating in strong magnetic fields
2Reliability
If multiple diaphragms with different shapes are used, then the frequency response becomes flat and sound quality improves, but the device complexity increases
Solution Approach 1:
The system segments the frequency response into multiple bands and assigns different diaphragm shapes to handle different frequency ranges. Multiple diaphragms with distinct geometries (circular, rectangular, triangular, etc.) are used to segment the audio spectrum, with each diaphragm optimized for its specific frequency band, thereby achieving good sound quality across all frequencies while maintaining compatibility with strong magnetic field environments
Solution Approach 2:
The patent changes the geometric parameters of the diaphragms (shape, size, thickness distribution) to optimize their transfer characteristics for specific frequency bands. By carefully designing and adjusting these physical parameters, the system achieves complementary response characteristics that when combined produce a flat overall frequency response, effectively managing complexity through purposeful parameter variation
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 system achieves improved sound quality with a flat frequency response and effective noise reduction, making it suitable for use in strong magnetic fields and environments like MRI devices.
Implementation Method 1
A piezoelectric speaker generates a sound by a piezoelectric element (transformed by a voltage) and a diaphragm (it is called 'shim material') for piezoelectric element attached thereto
Data Source
AI summary
According to one embodiment, a speaker system includes a plurality of filters and a plurality of speakers. The filters filter a first signal to generate a plurality of second signals. The speakers convert the second signals into respective sound waves. Each speaker has a diaphragm and a vibration source installed in the diaphragm. Diaphragms of the speakers have at least two different shapes. Respective transfer characteristics of the diaphragms are different from each other. Each filter corresponding to the respective transfer characteristics is set such that a transfer characteristic of a synthetic sound wave of the respective sound waves approaches a target transfer characteristic.