Multi-Stage Piezo-Diaphragm Sensor Bandwidth Expansion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional piezo-diaphragm sensors have limited signal bandwidth, typically restricted to 2 kHz-5 kHz, which is insufficient for capturing the full range of audible audio frequencies (20 Hz-20 kHz), making them less effective for speech and sound detection applications, especially in environments with background noise.
Innovation Solution
A multi-stage sound and vibration sensor design incorporating a first and second piezo-diaphragm with a flexible bottom surface that generates a second resonance frequency, expanding the signal bandwidth by forming a two-degree-of-freedom system, thereby enhancing sensitivity at higher frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional single piezo-diaphragm sensor is used, then the device complexity is low, but the signal bandwidth is limited to 2 kHz-5 kHz
Solution Approach 1:
The sensor is divided into multiple independent piezo-diaphragm elements (first and second piezo-diaphragms) with different resonance frequencies. Each diaphragm segment captures a specific frequency range, and their combined output achieves a broader overall bandwidth (20 Hz-20 kHz) than any single element could provide alone.
Solution Approach 2:
The patent transitions from a single-degree-of-freedom system to a multi-degree-of-freedom system by adding multiple piezo-diaphragms with different mechanical properties. This dimensional expansion in the frequency domain allows simultaneous coverage of low-frequency (20 Hz-2 kHz) and high-frequency (5 kHz-20 kHz) ranges through properly tuned resonance frequencies.
2Manufacturing precision
If multiple piezo-diaphragms with different resonance frequencies are used, then the signal bandwidth is expanded, but the device complexity increases
Solution Approach 1:
Multiple piezo-diaphragm elements serve universal sensing functions - each can detect both sound pressure and structure-borne vibrations. The first piezo-diaphragm optimized for low frequencies and the second for high frequencies work together as a unified multi-functional sensor system, eliminating the need for separate sensors for different frequency ranges.
Solution Approach 2:
The patent systematically varies key parameters of the piezo-diaphragms including size, thickness, and material composition to achieve different resonance frequencies. By controlling these physical parameters, the system optimizes each diaphragm's frequency response characteristics to complement the others, achieving broad bandwidth coverage through parameter diversification rather than structural complexity.
3Ease of manufacture
If a single piezo-diaphragm is used, then the manufacturing cost is low, but the sensitivity at higher frequencies is insufficient
Solution Approach 1:
The sensing function is segmented across multiple piezo-diaphragms with specialized frequency responses. The second piezo-diaphragm is specifically designed with parameters optimized for high-frequency detection (5 kHz-20 kHz), providing enhanced sensitivity in this range that a single general-purpose diaphragm could not achieve, while maintaining cost-effectiveness through standardized manufacturing processes.
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 expanded signal bandwidth allows for improved detection of voice commands and background noise, increasing sensitivity and accuracy in speech recognition and noise cancellation applications, while maintaining environmental robustness and cost-effectiveness.
Implementation Method 1
Due to the piezoelectric effect presented by the piezoelectric ceramic disk that converts electrical signals (e.g., voltage, charge) into mechanical signals (e.g., deformation, strain, etc.) and vice versa
Implementation Method 2
The first piezo-diaphragm and the second piezo-diaphragm provide a first resonance frequency and a second resonance frequency in response to the input signal
Data Source
AI summary
In at least one embodiment, a multi-stage sound and vibration sensor is provided. The multi-stage sound and vibration sensor includes a housing, a first piezo-diaphragm and a second piezo diaphragm. The first piezo-diaphragm and the second piezo-diaphragm are positioned in the housing to detect an input signal including audio or vibrations. The first piezo-diaphragm and the second piezo-diaphragm provide a first resonance frequency and a second resonance frequency in response to detecting the audio or the vibrations.