Flat-Disk Piezoelectric Transducer for Low-Frequency Beam Collimation
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Solution Overview
Problem
Existing methods for producing collimated sound beams at low frequencies (<1 MHz) are limited by high divergence and low intensity, making them impractical for applications like imaging through bone or opaque media, and require large transducers or complex parametric arrays.
Innovation Solution
A method involving a flat disk piezoelectric transducer excited at radial mode frequencies, optionally clamped and embedded in a dissimilar material, to generate a Bessel-like collimated sound beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high frequency transducers are used to produce collimated sound beams, then lateral resolution and depth of field are improved, but attenuation and penetration are worsened
Solution Approach 1:
The patent changes the operating frequency parameter from high frequency (>1 MHz) to low frequency (<1 MHz) while using a specially designed flat disk piezoelectric transducer with radial mode excitation. This parameter change allows the system to achieve collimated sound beams at low frequencies, overcoming the traditional trade-off between resolution and penetration by operating in a frequency range that provides both adequate collimation and reduced attenuation in opaque media
2Shape
If large diameter transducers are used to produce low frequency collimated sound beams, then collimation is improved, but device complexity and practicality are worsened
Solution Approach 1:
The patent changes the excitation mode parameter from conventional axial mode to radial mode excitation in a flat disk piezoelectric transducer. This parameter change enables the transducer to produce collimated sound beams at low frequencies without requiring large diameter, making the device practical for various applications while maintaining good collimation properties
Solution Approach 2:
The patent utilizes radial mode vibration of the flat disk piezoelectric transducer to generate collimated sound beams. By exciting the transducer at its radial mode resonance frequency, the system achieves efficient energy conversion and collimated beam formation at low frequencies without requiring large transducer dimensions
3Shape
If parametric arrays are used to produce low frequency collimated sound beams, then collimation is improved, but intensity is worsened
Solution Approach 1:
The patent uses radial mode vibration of a flat disk piezoelectric transducer to directly generate high intensity collimated sound beams at low frequencies. This approach avoids the intensity losses associated with parametric array mixing while maintaining good collimation, providing a more efficient solution for low frequency acoustic imaging applications
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
Produces a collimated sound beam with low divergence and high intensity at frequencies below 1 MHz, suitable for imaging through opaque media without the need for large transducers or complex designs.
Implementation Method 1
exciting a flat disk piezoelectric transducer at one or more radial mode excitation frequencies to generate a vibration of the flat disk piezoelectric transducer
Data Source
AI summary
A method of and system for producing a Bessel-like collimated sound beam frequencies below 1 MHz, and a device for sound (acoustic) imaging. A flat disk piezoelectric transducer having a large diameter/thickness ratio may be configured to exhibit radial vibration modes in the desired frequency range according to one or more parameters, including the diameter/thickness ratio, materials, electrode coverage, etc. The transducer may be driven by a waveform generator at one or more radial mode excitation frequencies.