Patent Publication Number: US-2022231220-A1

Title: Flexoelectricity ultrasonic transducer imaging system

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional Patent Application No. 63/140,231, filed Jan. 21, 2021, which is incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     1. Field 
     The present disclosure is related to imaging systems, and more particularly to ultrasonic imaging systems. 
     2. Prior Art 
     Known ultrasonic nondestructive testing applications utilize high-frequency sound waves for flaw detection and thickness gaging of objects and/or layers of material on the objects. These applications utilize test systems that include a plurality of ultrasonic transducers (UT transducers), where each UT transducer is generally a small probe that produces, transmits, and receives the high-frequency sound waves. These small probes may be combined to form larger phased arrays of probes that generate steered sound beams to perform the ultrasonic nondestructive testing. 
     Unfortunately, known UT transducers are made of piezoelectric crystals actuators. These actuators are ridge piezo crystals that require high voltages to see the changes electric polarization due to movement. Moreover, the rigidity and the size of the these known piezo crystals limit their utilization for portable UT imaging systems that can be utilized for flaw detection and thickness gagging of objects that have varying surfaces. As such, there is a need for a UT imaging sensor that addresses these issues. 
     SUMMARY 
     A flexoelectric ultrasonic (UT) transducer imaging system comprising a polytetrafluoroethylene (PTFE) layer, a plurality of flexoelectricity UT transducers, and a multiplexer is disclosed. The PTFE layer includes a front surface and a back surface and the plurality of flexoelectricity UT transducers is attached to the back surface of the PTFE layer. Each UT transducer of the plurality of flexoelectricity UT transducers has a front-end and a back-end and the front-end of each UT transducer is attached to the back surface of the PTFE layer, where the PTFE layer is configured as an audio membrane of the front-end of each UT transducer. The plurality of flexoelectricity UT transducers is arranged along the back surface of the PTFE layer as a two-dimensional array and each UT transducer is configured to vibrate in a normal direction to the back surface of the PTFE layer. The multiplexer in signal communication with each UT transducer, where the plurality of flexoelectricity UT transducers is sandwiched between the multiplexer and the PTFE layer. 
     In an example of operation, the flexoelectricity UT transducer imaging system is placed on a part under inspection, covering the part. A first set of voltages are applied to the plurality of flexoelectricity UT transducers with the multiplexer to produce vibrations in the plurality of flexoelectricity UT transducers. The vibrations of the plurality of flexoelectricity UT transducers and the PTFE layer produce the sounds waves that are transmitted towards the part under inspection with the PTFE layer. A plurality of reflected sound waves from the part under inspection are then received with the PTFE layer which cause the flexoelectricity UT transducers to vibrate and produce a second set of voltages that are received by the multiplexer. The multiplexer then transmits pixel data corresponding to each UT transducer within the two-dimensional array to a controller to produce a full image of the part under inspection. 
     Other devices, apparatuses, systems, methods, features, and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional devices, apparatuses, systems, methods, features, and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The invention may be better understood by referring to the following figures. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views. 
         FIG. 1  is a system block diagram of an example of an implementation of a flexoelectricity UT transducer imaging system in accordance with the present disclosure. 
         FIG. 2  is a side-view of the flexoelectricity UT transducer imaging system, shown in  FIG. 1 , placed on a non-linear part under inspection in accordance with the present disclosure. 
         FIG. 3  is a system block diagram of an example of an implementation of a distribution of the plurality of flexoelectricity UT transducers along a back surface of the polytetrafluoroethylene (PTFE) layer shown in  FIGS. 1 and 2  in accordance with the present disclosure. 
         FIG. 4A  is a system block diagram of an example of an implementation of a UT transducer, shown in  FIGS. 1-3 , in the rest state in accordance with the present disclosure. 
         FIG. 4B  is a system block diagram of the UT transducer, shown in  FIGS. 1-4A , in the active low-frequency state in accordance with the present disclosure. 
         FIG. 4C  is a system block diagram of the UT transducer, shown in  FIGS. 1-4B , in the active high-frequency state in accordance with the present disclosure. 
         FIG. 4D  is a system block diagram of the UT transducer, shown in  FIGS. 1-4C , in the passive receive state in accordance with the present disclosure. 
         FIG. 5  is a system block diagram of an example of an implementation of the flexoelectricity UT transducer imaging system, shown in  FIGS. 1-2 , operating in a first mode of operation in accordance with the present disclosure. 
         FIG. 6  is a system block diagram of the flexoelectricity UT transducer imaging system, shown in  FIGS. 1-2 , operating in another mode of operation in accordance with the present disclosure. 
         FIG. 7  is a flowchart of an example of an implementation of a method performed by the flexoelectricity UT transducer imaging system shown in  FIGS. 1-2  in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Disclosed is a flexoelectricity ultrasonic (UT) transducer imaging system comprising a polytetrafluoroethylene (PTFE) layer, a plurality of flexoelectricity UT transducers, and a multiplexer. The PTFE layer includes a front surface and a back surface and the plurality of flexoelectricity UT transducers is attached to the back surface of the PTFE layer. Each UT transducer of the plurality of flexoelectricity UT transducers has a front-end and a back-end and the front-end of each UT transducer is attached to the back surface of the PTFE layer, where the PTFE layer is configured as an audio membrane of the front-end of each UT transducer. The plurality of flexoelectricity UT transducers is arranged along the back surface of the PTFE layer as a two-dimensional array and each UT transducer is configured to vibrate in a normal direction to the back surface of the PTFE layer. The multiplexer in signal communication with each UT transducer, where the plurality of flexoelectricity UT transducers is sandwiched between the multiplexer and the PTFE layer. 
     In an example of operation, the flexoelectricity UT transducer imaging system is placed on a part under inspection, covering the part. A first set of voltages are applied to the plurality of flexoelectricity UT transducers with the multiplexer to produce vibrations in the plurality of flexoelectricity UT transducers. The vibrations of the plurality of flexoelectricity UT transducers and the PTFE layer produce the sounds waves that are transmitted towards the part under inspection with the PTFE layer. A plurality of reflected sound waves from the part under inspection are then received with the PTFE layer which cause the flexoelectricity UT transducers to vibrate and produce a second set of voltages that are received by the multiplexer. The multiplexer then transmits pixel data corresponding to each UT transducer within the two-dimensional array to a controller to produce a full image of the part under inspection. 
     Turning to  FIG. 1 , a system block diagram of an example of an implementation of the flexoelectricity UT transducer imaging system  100  is shown in accordance with the present disclosure. In this example, the flexoelectricity UT transducer imaging system  100  is placed on the on a top of part under inspection  102  that linear component. The flexoelectricity UT transducer imaging system  100  may include a polytetrafluoroethylene (PTFE) layer  104 , a plurality of flexoelectricity UT transducers  106 , a multiplexer  108 , and a controller  110 . The PTFE layer  104  includes a front surface  112  and a back surface  114  and the plurality of flexoelectricity UT transducers  106  are attached to the back surface  114  of the PTFE layer  104 . In this example, each UT transducer of the plurality of flexoelectricity UT transducers  106  has a front-end and a back-end where the front-end of each UT transducer is attached to the back surface  114  of the PTFE layer  104 . The PTFE layer  104  is configured as an audio membrane of the front-end of each UT transducer and the plurality of flexoelectricity UT transducers  106  is arranged along the back surface  114  of the PTFE layer  104  as a two-dimensional array. In this example, each UT transducer is configured to vibrate in a normal direction to the back surface  114  of the PTFE layer  104 . In this example, the PTFE layer  104  may be placed on the part under inspection  102  utilizing a UT gel  116  to form an approximate vacuum seal between the font surface  112  of the PTFE layer  104  and the surface  118  of the part under inspection  102 . 
     In this example, the controller  110  may be any device capable of receiving pixel data from each UT transducer in the plurality of flexoelectricity UT transducers  106  and, in response, produce a full image of the part under inspection  102 , where the image may be utilized for flaw detection and thickness gaging of the part under inspection  102 . The controller  110  may be, for example, a field programmable gate array (FPGA) or a computing device that includes that one or more processors that include, for example, a microprocessor, a single-core processor, a multi-core processor, a microcontroller, an application-specific integrated circuit (ASIC), a logic device (e.g., a programmable logic device configured to perform processing operations), a digital signal processing (DSP) device, one or more memories for storing executable instructions (e.g., software, firmware, or other instructions), and/or any other appropriate combination of processing device and/or memory to execute instructions to perform any of the various operations described in the memory and other devices via the one or more communication interfaces to perform method and processing steps as described herein. The one or more communication interfaces include wired or wireless communication buses. 
     In various examples, it is appreciated by those of ordinary skill in the art that the processing operations and/or instructions may be integrated in software and/or hardware as part of the one or more processors, or code (e.g., software or configuration data), which is stored in the memory. The examples of processing operations and/or instructions disclosed in the present disclosure may be stored by a machine-readable medium in a non-transitory manner (e.g., a memory, a hard drive, a compact disk, a digital video disk, or a flash memory) to be executed by the one or more processors (e.g., a computer such as a logic or processor-based system) to perform various methods disclosed herein. In this example, the machine-readable medium may be residing in memory within the computing device but it is appreciated by those of ordinary skill that the machine-readable medium may be located on other memory external to the controller. 
     In this example, the PTFE layer  104  may be implemented as, or part of, a blanket of the flexoelectricity UT transducer imaging system  100 . If the blanket is separate from the PTFE layer  104 , the blanket layer may be attached to the PTFE layer  104  and include a front surface and a back surface, where the PTFE layer  104  is attached to the back surface of the blanket layer, and the front surface is configured to attach to a part under inspection  102 . In this example, the blanket may be a separate component to protect the structural integrity of the PTFE layer  104  or simply a flexible version of the PTFE layer  104  that extends beyond a physical footprint of the plurality of the UT transducers  106 . 
     Moreover, the flexoelectricity UT transducer imaging system  100  may include, or be in signal communication with, a power source (not shown) to provide a set of excitation voltages to the flexoelectricity UT transducers of the plurality of flexoelectricity UT transducers  106 . In this example, the power source provides voltages that, for example, may be less than approximately 80 volts. 
       FIG. 2  is a side-view of the flexoelectricity UT transducer imaging system  100  placed on a non-linear part under inspection  200  in accordance with the present disclosure. In this example, the controller  110  is shown as remote from the combination of the PTFE layer  104 , plurality of flexoelectricity UT transducers  106 , and multiplexer  108  but still in signal communication via signal path  202  that may be a wired or wireless connection. 
     It is appreciated by those of ordinary skill in the art that the circuits, components, modules, and/or devices of, or associated with, the flexoelectricity UT transducer imaging system  100  are described as being in signal communication with each other, where signal communication refers to any type of communication and/or connection between the circuits, components, modules, and/or devices that allows a circuit, component, module, and/or device to pass and/or receive signals and/or information from another circuit, component, module, and/or device. The communication and/or connection may be along any signal path between the circuits, components, modules, and/or devices that allows signals and/or information to pass from one circuit, component, module, and/or device to another and includes wireless or wired signal paths. The signal paths may be physical, such as, for example, conductive wires, electromagnetic wave guides, cables, attached and/or electromagnetic or mechanically coupled terminals, semi-conductive or dielectric materials or devices, or other similar physical connections or couplings. Additionally, signal paths may be non-physical such as free-space (in the case of electromagnetic propagation) or information paths through digital components where communication information is passed from one circuit, component, module, and/or device to another in varying digital formats, without passing through a direct electromagnetic connection. 
     In  FIG. 3 , a system block diagram of an example of an implementation of a distribution of the plurality of flexoelectricity UT transducers  106  along the back surface  114  of the PTFE layer  104  is shown in accordance with the present disclosure. In this example, the plurality of flexoelectricity UT transducers  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  314 , and  316  are attached to the back surface  114  of the PTFE layer  104 . The plurality of flexoelectricity UT transducers  300  correspond to pixel elements on of the flexoelectricity UT transducer imaging system  100  and may be oriented in rows and columns along the back surface  114  of the PTFE layer  104 . As an example, the flexoelectricity UT transducers  300 ,  302 ,  304 , and  306  may be oriented along a first row  318  and the flexoelectricity UT transducers  300 ,  308 ,  310 , and  312  may be oriented along a first column  320 . As stated earlier, the front-end of each flexoelectricity UT transducer is attached to the back surface  114  of the PTFE layer  104 . As an example, the first front-end  322  of a first flexoelectricity UT transducer  300 , second front-end  324  of a second flexoelectricity UT transducer  306 , third front-end  326  of a third flexoelectricity UT transducer  312 , and forth front-end  328  of a fourth flexoelectricity UT transducer  316  are all attached to the back surface  114  of the PTFE layer  104 . In this example, the multiplexer  108  is in signal communication with each flexoelectricity UT transducers  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  314 , and  316  and either applies a set of voltages signals to the flexoelectricity UT transducers  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  314 , and  316  or receives another set of voltages signals from the flexoelectricity UT transducers  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  314 , and  316  when received sound waves at the PTFE layer  104  are detected by the flexoelectricity UT transducers  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  314 , and  316 . 
     As discussed earlier, the plurality of flexoelectricity UT transducers  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  314 , and  316  are arranged as a two-dimensional array on the back surface  114  of the PTFE layer  104 , where each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  314 , and  316  corresponds to a pixel of the two-dimensional array. In this example, the size of the two-dimensional array may optionally vary based on the design preferences of the flexoelectricity UT transducer imaging system  100 . As an example, the two-dimensional array may be as small as a 2 by 2 array and as large as a needed such as, for example, a 1,000 by 1,000 array or larger. As such, the number of flexoelectricity UT transducers may vary from four (4) to millions of elements. 
     Turning to  FIGS. 4A-4D , a flexoelectricity UT transducer  400  of the plurality of flexoelectricity UT transducers  106  is shown. In this example, the flexoelectricity UT transducer  400  is shown in resting state in  FIG. 4A , an active low-frequency state in  FIG. 4B , an active high-frequency state in  FIG. 4C , and a passive receiving state in  FIG. 4D . In this example, the flexoelectricity UT transducer includes a front-end  402  and a back-end  404 . The front-end  402  of the flexoelectricity UT transducer  400  is attached to the back surface  114  of the PTFE layer  104 . The flexoelectricity UT transducer  400  may include and be constructed of one or more flexoelectricity crystal elements  406 ,  408 ,  410 , and  412 . 
     In this example, for the purpose of illustration, only four flexoelectricity crystal elements  406 ,  408 ,  410 , and  412  are shown, however, it is appreciated by those of ordinary skill in the art that any number of flexoelectricity crystal elements  406 ,  408 ,  410 , and  412  may be utilized in forming flexoelectricity UT transducer  400  where the plurality of flexoelectricity crystal elements is arranged as in a stacked-up structure as shown. As such, in this example the front-end  402  of the flexoelectricity UT transducer  400  corresponds to the front-end of the first flexoelectricity crystal elements  406 . In this example, each flexoelectricity crystal elements  406 ,  408 ,  410 , and  412  is in signal communication with the multiplexer  108  via a plurality of signal paths  414 ,  416 ,  418 , and  420 , respectively. Moreover, in this example, each of the flexoelectricity crystal elements  406 ,  408 ,  410 , and  412  may be constructed of a polarized ceramic material such as, for example, Barium Titanate (BaTiO 3 ). Furthermore, in this example, the front-end  402  of the flexoelectricity UT transducer  400  has a corresponding front-end impedance that is matched to a PTFE impedance of the PTFE layer  104 . 
     The polarized ceramic material of the flexoelectricity crystal elements  406 ,  408 ,  410 , and  412  reacts to applied voltages to align themselves along the applied voltage such that when voltages are applied to the flexoelectricity crystal elements  406 ,  408 ,  410 , and  412 , the polarized ceramic material of the flexoelectricity crystal elements  406 ,  408 ,  410 , and  412  will align and expand in both a vertical direction  422  and horizontal direction  424 . 
     In an example of operation for transmitting, initially the flexoelectricity UT transducer  400  is in a resting where no voltage is applied to the flexoelectricity crystal elements  406 ,  408 ,  410 , and  412 . The flexoelectricity UT transducer  400  will have an initial height  426  and initial width  428 . When a first set of voltages are applied in a low-frequency mode, the polarize material within flexoelectricity crystal elements  406 ,  408 ,  410 , and  412  will align itself along the applied first set of applied voltages such that flexoelectricity UT transducer  400  will increase in height to a second height  430  and increase the width of some of the flexoelectricity crystal elements  406 ,  408 ,  410 , and  412  to be greater than the initial width  428 . When the applied first set of voltages are removed, the flexoelectricity crystal elements  406 ,  408 ,  410 , and  412  will return to the resting state shown in  FIG. 4A . By applying alternating current (AC) voltages  401 ,  403 ,  405 , and  407  to the flexoelectricity crystal elements  406 ,  408 ,  410 , and  412 , the flexoelectricity UT transducer  400  may vertically vibrate  432  (in a normal direction, i.e., perpendicular to the back surface  114  of the PTFE layer  104 ) and horizontally vibrate  434 . These vertical  432  and horizontal  434  vibrations will produce mechanical forces on the back surface  114  of the PTFE layer  104  producing low-frequency vibrations  436  of sound waves which are transmitted to the part under inspection  102  by the PTFE layer  104 . 
     If the applied voltages are increased in the high-frequency mode, a second set of voltages  409 ,  411 ,  413 , and  415  are applied in the high-frequency mode, the polarize material within flexoelectricity crystal elements  406 ,  408 ,  410 , and  412  will further align itself along the applied second set of applied voltages such that flexoelectricity UT transducer  400  will further increase in height to a third height  438  and further increase the width of some of the flexoelectricity crystal elements  406 ,  408 ,  410 , and  412  to be greater than the initial width  428 . Again, when the applied second set of voltages are removed, the flexoelectricity crystal elements  406 ,  408 ,  410 , and  412  will return to the resting state shown in  FIG. 4A . By applying AC voltages for the second set of applied voltages to the flexoelectricity crystal elements  406 ,  408 ,  410 , and  412 , the flexoelectricity UT transducer  400  will vertically vibrate  440  and horizontally vibrate  442  stronger than the example in  FIG. 4B . These vertical  440  and horizontal  442  vibrations will again produce mechanical forces on the back surface  114  of the PTFE layer  104  producing high-frequency vibrations  444  of sound waves which are transmitted to the part under inspection  102  by the PTFE layer  104 . 
     In an example of operation for receiving reflected sound waves  446 , the reverse process occurs. The flexoelectricity UT transducer  400  receives the received reflected sound waves  446  at the front source  112  of the PTFE layer  104 . The received reflected sound waves  446  cause deflections to the PTFE layer  104  that cause the flexoelectricity UT transducer  400  to deflect since it is attached to the back surface  114  of the PTFE layer  104 . The deflection of the PTFE layer  104  will cause the flexoelectricity UT transducer  400  to vibrate vertically  448  and horizontally  450  which will induce a first voltage  452  from the first flexoelectricity crystal elements  406 , a second voltage  454  from the second flexoelectricity crystal elements  408 , a third voltage  456  from the third flexoelectricity crystal elements  410 , and a fourth voltage  458  from the fourth flexoelectricity crystal elements  412 . These voltages will be received by the multiplexer  108  and passed to the controller  110 . 
     In this example, it is noted that the multiplexer  108  may be configured to drive or receive a very large number of voltages because the multiplexer  108  is in signal communication with each flexoelectricity crystal elements  406 ,  408 ,  410 , and  412  of each UT transducer  400  in an M by N two-dimensional array of flexoelectricity UT transducers  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  314 , and  316  that may be over a million, where M is the number of flexoelectricity UT transducers  300 ,  302 ,  304 , and  306  along the row  318  and Nis the number of flexoelectricity UT transducers  300 ,  306 ,  310 , and  312  along the column  320 . 
       FIG. 5  is a system block diagram of an example of an implementation of the flexoelectricity UT transducer imaging system  100  operating in a first mode of operation in accordance with the present disclosure. In this example, the plurality of flexoelectricity UT transducers  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  314 , and  316  are arranged into sub-pluralities, where the sub-pluralities are columns along the back surface  114  of the PTFE layer  104 . Moreover, in this example, a first sub-plurality  500  of the flexoelectricity UT transducers may include two columns  502  and  504  of flexoelectricity UT transducers. The second sub-plurality  506  of the flexoelectricity UT transducers may include all of the other flexoelectricity UT transducers not included in the first sub-plurality  500  of the flexoelectricity UT transducers. For purpose of ease of illustration only two the flexoelectricity UT transducers  502  and  504  are shown in the first sub-plurality  500 , however, it is appreciated that the number of flexoelectricity UT transducers within the first sub-plurality  500  may vary based on the design. 
     In this example, the flexoelectricity UT transducers  502  and  504  in combination with the PTFE layer  104  produce a plurality of sound waves that transmitted towards the part under inspection  102 . The resulting reflected sound waves from the part under inspection  102  are received by the second sub-plurality  506  of the flexoelectricity UT transducers and not the flexoelectricity UT transducers  502  and  504  of the first sub-plurality  500  of the flexoelectricity UT transducers. In this example, the individual flexoelectricity UT transducers within the second sub-plurality  506  of the flexoelectricity UT transducers produce a set of voltages that are received by the multiplexer  108 . 
     Turning to  FIG. 6 , a system block diagram of the flexoelectricity UT transducer imaging system  100  is shown operating in another mode of operation in accordance with the present disclosure. In this example, the plurality of flexoelectricity UT transducers  106  is arranged as a two-dimensional array of flexoelectricity UT transducers  600  where some of the flexoelectricity UT transducers (i.e., a first sub-plurality) are utilized to produce the sound waves that are transmitted to the part under inspection  102 . This first sub-plurality  602  of flexoelectricity UT transducers  603  is located, for example, at the center of the two-dimensional array of flexoelectricity UT transducers  600 . In this example, a second sub-plurality  604  of flexoelectricity UT transducers  605  includes all of the flexoelectricity UT transducers in the two-dimensional array of flexoelectricity UT transducers  600  excluding the first sub-plurality  602  of flexoelectricity UT transducers. 
     Similar to the previous example, in this example, the flexoelectricity UT transducers of the first sub-plurality  602  of flexoelectricity UT transducers in combination with the PTFE layer  104  produce a plurality of sound waves that transmitted towards the part under inspection  102 . The resulting reflected sound waves from the part under inspection  102  are received by the second sub-plurality  604  of the flexoelectricity UT transducers and not the flexoelectricity UT transducers of the first sub-plurality  602  of the flexoelectricity UT transducers. Again, the individual flexoelectricity UT transducers within the second sub-plurality  602  of the flexoelectricity UT transducers produce a set of voltages that are received by the multiplexer  108 . 
     It is appreciated that other combinations may also be utilized by the flexoelectricity UT transducer imaging system  100 . In these examples, the controller  110  may be programmed to utilize different combinations for different measurements based on the part under inspection  102  or other factors. 
     In  FIG. 7 , a flowchart of an example of an implementation of the method  700  performed by the flexoelectricity UT transducer imaging system  100  is shown accordance with the present disclosure. The method  700  begins by covering  702  the part under inspection  102  with the flexoelectricity UT transducer imaging system  100  and applying  704  a first set of voltages  401 ,  403 ,  405 ,  407 ,  409 ,  411 ,  413 ,  415  to the plurality of flexoelectricity UT transducers  106  with the multiplexer  108  to produce vibrations in the plurality of flexoelectricity UT transducers  106 . The method  700  then includes transmitting  706  a plurality of sound waves  436  or  444  towards the under inspection  102  with the PTFE layer  104 , where the plurality of sound waves  436  or  444  are produced by a combination of the PTFE layer  104  and the vibrations of the plurality of flexoelectricity UT transducers  106 . The method  700  then includes receiving  708  a plurality of reflected sound waves  446  from the part under inspection  102  with the PTFE layer  104  and producing  710  a second set of voltages from the plurality of flexoelectricity UT transducers  106  that are received  712  by the multiplexer  108 . The method  700  then includes transmitting  714  the pixel data from each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 , or  400  to the controller  110  to produce a full image of the part under inspection  102  and producing  716  the full image with the controller  110 . The method then ends. 
     In this example, the step of producing  710  a second set of voltages from the plurality of flexoelectricity UT transducers  106  includes producing a sub-set of voltages  452 ,  454 ,  456 , and  458  from each flexoelectricity crystal element  406 ,  408 ,  410 , and  412  of each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 , or  400 . Moreover, the step of receiving  712  the second set of voltages from the plurality of flexoelectricity UT transducers  106  with the multiplexer  108  includes receiving the sub-set of voltages  452 ,  454 ,  456 , and  458  from each flexoelectricity crystal element  406 ,  408 ,  410 , and  412  of each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 , or  400 . 
     In the method  700 , the transmitting step  706  may also include producing the plurality of sound waves  436  or  444  from a combination of the PTFE layer  104  and the vibration of a first sub-plurality  500  or  602  of the flexoelectricity UT transducers  106 , receiving the plurality of reflected sound waves  446  from the part under inspection  102  with the PTFE layer  104  and a second sub-plurality  506  or  602  of flexoelectricity UT transducers  106 , and producing the second set of voltages from the second sub-plurality  506  or  602  of flexoelectricity UT transducers  106 . In this example, the first sub-plurality  500  or  602  of the flexoelectricity UT transducers  106  has a pattern within the two-dimensional array  600 . In this example, the first set of voltages  401 ,  403 ,  405 ,  407 ,  409 ,  411 ,  413 ,  415  may be less than approximately 80 volts. 
     Further, the disclosure comprises the following examples, whereby the scope of protection is provided by the claims. 
     Example 1. A flexoelectricity ultrasonic (UT) transducer imaging system  100  comprising: a polytetrafluoroethylene (PTFE) layer  104  having a front surface  112  and a back surface  114 ; a plurality of flexoelectricity UT transducers  106  attached to the back surface  114  of the PTFE layer  104 , wherein each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400  of the plurality of flexoelectricity UT transducers  106  has a front-end  322 ,  324 ,  326 ,  328 ,  402  and a back-end  404 , the front-end  322 ,  324 ,  326 ,  328 ,  402  of each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400  is attached to the back surface  114  of the PTFE layer  104 , wherein the PTFE layer  104  is configured as an audio membrane of the front-end  322 ,  324 ,  326 ,  328 ,  402  of each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400 , the plurality of flexoelectricity UT transducers  106  is arranged along the back surface  114  of the PTFE layer  104  as a two-dimensional array, and each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400  is configured to vibrate in a normal direction to the back surface  114  of the PTFE layer  104 ; and a multiplexer  108  in signal communication with each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400 , wherein the plurality of flexoelectricity UT transducers  106  is sandwiched between the multiplexer  108  and the PTFE layer  104 . 
     Example 2. The flexoelectricity UT transducer imaging system  100  of example 1, wherein each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400  of the plurality of flexoelectricity UT transducers  106  is a constructed of a flexoelectricity crystal element  406 ,  408 ,  410 ,  412 . 
     Example 3. The flexoelectricity UT transducer imaging system  100  of example 2, wherein the flexoelectricity crystal element  406 ,  408 ,  410 ,  412  is a Barium Titanate (BaTiO 3 ) crystal element. 
     Example 4. The flexoelectricity UT transducer imaging system  100  of example 2 or 3, wherein each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400  comprises a plurality of flexoelectricity crystal elements  406 ,  408 ,  410 ,  412  arranged in a stacked-up structure. 
     Example 5. The flexoelectricity UT transducer imaging system  100  of example 4, wherein the multiplexer  108  is in signal communication with each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400  of the plurality of flexoelectricity UT transducers  106 . 
     Example 6. The flexoelectricity UT transducer imaging system  100  of example 5, wherein the multiplexer  108  is in signal communication with each flexoelectricity crystal element  406 ,  408 ,  410 ,  412  of the plurality of flexoelectricity crystal elements  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400 . 
     Example 7. The flexoelectricity UT transducer imaging system  100  of example 1, wherein the front-end  322 ,  324 ,  326 ,  328 ,  402  of each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400  has a corresponding front-end impedance, the PTFE layer  104  has a PTFE impedance, and the corresponding front-end impedance for each flexoelectricity UT transducer and the PTFE impedance are matched. 
     Example 8. The flexoelectricity UT transducer imaging system  100  of example 1, further comprising a blanket layer attached to the PTFE layer  104 , wherein the blanket layer includes a front surface and a back surface, the PTFE layer  104  is attached to the back surface of the blanket layer, and the front surface is configured to attach to a part under inspection  102 . 
     Example 9. The flexoelectricity UT transducer imaging system  100  of example 1, further comprising a controller  110  in signal communication with the multiplexer  108 . 
     Example 10. The flexoelectricity UT transducer imaging system  100  of example 9, wherein each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400  of the plurality of flexoelectricity UT transducers  106  corresponds to a pixel of the two-dimensional array and the controller  110  is configured to receive pixel data from each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400  and, in response, produce a full image of a part under inspection  102 . 
     Example 11. A method for inspecting a part under inspection  102  utilizing the flexoelectricity UT transducer imaging system  100  of example 1. 
     Example 12. A method  700  for inspecting a part  102  with a flexoelectricity UT transducer imaging system  100 , the method  700  comprising: covering  702  the part  102  with the flexoelectricity UT transducer imaging system  100  having a polytetrafluoroethylene (PTFE) layer  104 , a plurality of flexoelectricity UT transducers  106  attached to a back surface  114  of the PTFE layer  104 , and a multiplexer  108  in signal communication with each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400  of the plurality of flexoelectricity UT transducers  106 , wherein the plurality of flexoelectricity UT transducers  106  is sandwiched between the multiplexer  108  and the PTFE layer  104  and the plurality of flexoelectricity UT transducers  106  is arranged along the back surface  114  of the PTFE layer  104  as a two-dimensional array, wherein each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400  corresponds to a pixel of the two-dimensional array; applying  704  a first set of voltages  401 ,  403 ,  405 ,  407 ,  409 ,  411 ,  413 ,  415  to the plurality of flexoelectricity UT transducers  106  with the multiplexer  108  to produce vibrations in the plurality of flexoelectricity UT transducers  106 ; transmitting  706  a plurality of sound waves  436 ,  444  towards the part  102  with the PTFE layer  104 , wherein the plurality of sound waves  436 ,  444  are produced by a combination of the PTFE layer  104  and the vibrations of the plurality of flexoelectricity UT transducers  106 ; receiving  708  a plurality of reflected sound waves  446  from the part  102  with the PTFE layer  104 ; producing  710  a second set of voltages from the plurality of flexoelectricity UT transducers  106 ; receiving  712  the second set of voltages from the plurality of flexoelectricity UT transducers  106  with the multiplexer  108 ; and transmitting  714  the pixel data from each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400  to a controller  110  to produce a full image of the part  102 . 
     Example 13. The method  700  of example 12, wherein each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400  of the plurality of flexoelectricity UT transducers  106  is a constructed of a flexoelectricity crystal element  406 ,  408 ,  410 ,  412 . 
     Example 14. The method  700  of example 13, wherein the flexoelectricity crystal element  406 ,  408 ,  410 ,  412  is a Barium Titanate (BaTiO 3 ) crystal element. 
     Example 15. The method  700  of example 13, wherein each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400  comprises a plurality of flexoelectricity crystal elements  406 ,  408 ,  410 ,  412  arranged in a stacked-up structure, and wherein producing a second set of voltages from the plurality of flexoelectricity UT transducers  106  includes producing a sub-set of voltages  452 ,  454 ,  456 ,  458  from each flexoelectricity crystal element  406 ,  408 ,  410 ,  412  of each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400 . 
     Example  16 . The method  700  of example  15 , wherein the multiplexer  108  is in signal communication with each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400  of the plurality of flexoelectricity UT transducers  106 , and wherein receiving the second set of voltages from the plurality of flexoelectricity UT transducers  106  with the multiplexer  108  includes receiving the sub-set of voltages  452 ,  454 ,  456 ,  458  from each flexoelectricity crystal element  406 ,  408 ,  410 ,  412  of each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400 . 
     Example 17. The method  700  of example 12, wherein transmitting a plurality of sound waves  436 ,  444  towards the part  102  with the PTFE layer  104  includes producing the plurality of sound waves  436 ,  444  from a combination of the PTFE layer  104  and the vibration of a first sub-plurality  500  of the flexoelectricity UT transducers  106 , receiving the plurality of reflected sound waves  446  from the part  102  with the PTFE layer  104 , and producing the second set of voltages from a second sub-plurality of flexoelectricity UT transducers  106 . 
     Example 18. The method  700  of example 17, wherein the first sub-plurality of the flexoelectricity UT transducers  106  have a pattern within the two-dimensional array. 
     Example 19. The method  700  of example 12, further including receiving with the controller  110  pixel data from each flexoelectricity UT transducer  300 ,  302 ,  304 ,  306 ,  308 ,  310 ,  312 ,  316 ,  400  and, in response, produce a full image of the part under inspection  102 . 
     Example 20. The method  700  of example 12, wherein the first set of voltages  401 ,  403 ,  405 ,  407 ,  409 ,  411 ,  413 ,  415  are less than approximately 80 volts. 
     It will be understood that various aspects or details of the disclosure may be changed without departing from the scope of the disclosure. It is not exhaustive and does not limit the claimed disclosures to the precise form disclosed. Furthermore, the foregoing description is for the purpose of illustration only, and not for the purpose of limitation. Modifications and variations are possible in light of the above description or may be acquired from practicing the disclosure. 
     The claims and their equivalents define the scope of the disclosure. Moreover, although the techniques have been described in language specific to structural features and/or methodological acts, it is to be understood that the appended claims are not necessarily limited to the features or acts described. Rather, the features and acts are described as example implementations of such techniques. 
     To the extent that terms “includes,” “including,” “has,” “contains,” and variants thereof are used herein, such terms are intended to be inclusive in a manner similar to the term “comprises” as an open transition word without precluding any additional or other elements. Moreover, conditional language such as, among others, “can,” “could,” “might” or “may,” unless specifically stated otherwise, are understood within the context to present that certain examples include, while other examples do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that certain features, elements and/or steps are in any way required for one or more examples or that one or more examples necessarily include logic for deciding, with or without user input or prompting, whether certain features, elements and/or steps are included or are to be performed in any particular example. Conjunctive language such as the phrase “at least one of X, Y or Z,” unless specifically stated otherwise, is to be understood to present that an item, term, etc. may be either X, Y, or Z, or a combination thereof 
     In some alternative examples of implementations, the function or functions noted in the blocks may occur out of the order noted in the figures. For example, in some cases, two blocks shown in succession may be executed substantially concurrently, or the blocks may sometimes be performed in the reverse order, depending upon the functionality involved. Also, other blocks may be added in addition to the illustrated blocks in a flowchart or block diagram. Moreover, the operations of the example processes are illustrated in individual blocks and summarized with reference to those blocks. The processes are illustrated as logical flows of blocks, each block of which can represent one or more operations that can be implemented in hardware, software, or a combination thereof In the context of software, the operations represent computer-executable instructions stored on one or more computer-readable medium that, when executed by one or more processing units, enable the one or more processing units to perform the recited operations. Generally, computer-executable instructions include routines, programs, objects, modules, components, data structures, and the like that perform particular functions or implement particular abstract data types. The order in which the operations are described is not intended to be construed as a limitation, and any number of the described operations can be executed in any order, combined in any order, subdivided into multiple sub-operations, and/or executed in parallel to implement the described processes. The described processes can be performed by resources associated with one or more device(s) such as one or more internal or external CPUs or GPUs, and/or one or more pieces of hardware logic such as FPGAs, DSPs, or other types of accelerators. 
     All of the methods and processes described above may be embodied in, and fully automated via, software code modules executed by one or more general purpose computers or processors. The code modules may be stored in any type of computer-readable storage medium or other computer storage device. Some or all of the methods may alternatively be embodied in specialized computer hardware.