Transverse Width Mode Piezoelectric Transducer for Broadband Arrays
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Solution Overview
Problem
Conventional piezoelectric transducer arrays for sound and ultrasound generation and reception predominantly operate in the longitudinal mode due to superior longitudinal properties of PZT ceramics, while transverse mode arrays are less popular due to inferior transverse properties and fabrication difficulties, limiting their use in medical and underwater applications.
Innovation Solution
A new transverse width mode is introduced for piezoelectric transducers, where the active element is poled across two opposite faces and excited in a direction transverse to the poling direction, generating an acoustic beam at a right angle to the resonating width direction, utilizing relaxor-based ferroelectric/piezoelectric single crystals with enhanced transverse piezoelectric properties and lower sound velocities, enabling efficient sound and ultrasound generation and reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If transverse mode arrays are used, then fabrication difficulties are reduced and versatility is improved, but transverse piezoelectric properties are inferior compared to longitudinal mode
Solution Approach 1:
The patent changes the fundamental operating parameters of the transducer by switching from conventional longitudinal mode to transverse width mode operation. This involves changing the poling direction configuration and the excitation direction, thereby altering the piezoelectric coupling parameters from d33 to d31, which enables transverse mode operation with improved versatility while maintaining acceptable performance
Solution Approach 2:
The patent employs composite material structures combining piezoelectric active elements with specific backing materials and acoustic matching layers. This composite approach allows optimization of the transverse mode performance by carefully selecting and combining materials with complementary properties to compensate for the inherently inferior transverse piezoelectric coefficients
2Measurement precision
If active element dimension is reduced to λm/2, then main acoustic beam focus is improved and grating lobes are avoided, but acoustic power is reduced
Solution Approach 1:
The patent transitions from longitudinal mode operation to transverse width mode operation, effectively changing the dimensional configuration of the active element's operation. By exciting the transverse width dimension rather than the longitudinal dimension, the system achieves improved beam focus at element separations of λm/2 or less while the acoustic power is compensated through the array configuration and electronic beamforming techniques
3Ease of operation
If discrete transducer elements are spaced at λm/2 apart, then electronic beam steering is enabled and main acoustic beam is focused, but device complexity increases
Solution Approach 1:
The patent divides the transducer into discrete elemental transducers arranged in an array configuration. Each element can be independently controlled and phased, enabling electronic beam steering and focusing. The segmentation into manageable discrete elements simplifies the control architecture while achieving sophisticated beamforming capabilities through phased array techniques
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 approach allows for effective sound and ultrasound generation and reception in both transverse and longitudinal directions, enhancing sensitivity and bandwidth, and facilitating the use of transducer arrays in underwater, medical, and industrial fields with improved acoustic performance and ease of fabrication.
Implementation Method 1
piezoelectric transducers, where the active element is poled across two opposite faces and excited in a direction transverse to the poling direction
Implementation Method 2
when the active element is set in resonance in a direction transverse to the poling direction
Implementation Method 3
generating an acoustic beam at a right angle to the resonating transverse or width direction of the active element
Data Source
AI summary
The present invention provides a transverse width mode for sound and ultrasound generation and reception. The transverse width mode can be combined with conventional longitudinal or transverse mode to make sonic and ultrasonic transducers and/or arrays of multiple resonant modes, a broadband coupled mode or their combinations. Due to its half-wavelength resonance nature, when the transverse width mode is designed to operate with suitable head mass and/or matching layers, ultra broadband transducers of moderate to high sound pressure level can be realized. With active materials having low transverse sound velocities, the transverse dimensions of each transducer element can be kept about or smaller than half the wavelengths of sounds in water and human tissues, making the transverse width mode highly suited for various array designs and operations.