Planar phased array ultrasonic transducer

Abstract

The invention discloses a planar phased array ultrasonic transducer, and relates to the technical field of transducers, the planar phased array ultrasonic transducer comprises a 1-3 type piezoelectric composite board, a common positive electrode panel and a flexible circuit board, the 1-3 type piezoelectric composite board comprises a polymer frame and a plurality of PZT piezoelectric ceramic columns, all the PZT piezoelectric ceramic columns are embedded in the polymer frame in an array, and the PZT piezoelectric ceramic columns are connected with the flexible circuit board. One end of each PZT piezoelectric ceramic column is a positive electrode end, the other end of each PZT piezoelectric ceramic column is a negative electrode end, the common positive electrode panel is connected with the positive electrode ends of the PZT piezoelectric ceramic columns, the flexible circuit board is provided with a bonding pad area and at least one pin area, the bonding pad area is fixedly provided with a plurality of bonding pads, the pin area is fixedly provided with a plurality of pins, and the flexible circuit board is provided with a plurality of conductive terminals. All the pins, all the bonding pads and all the negative electrode ends of the PZT piezoelectric ceramic columns are in one-to-one correspondence, the bonding pads are electrically connected with the pins, and the bonding pads are connected with the negative electrode ends of the PZT piezoelectric ceramic columns; according to the invention, the PZT is applied to the planar phased array ultrasonic transducer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of transducers, in particular to a planar phased array ultrasonic transducer. BACKGROUND

[0002] The underwater acoustic transducer is the core sensing element in underwater communication, detection and imaging technologies, and undertakes the mission of transmitting and receiving acoustic signals in water, so it is also called the "ears and eyes of underwater acoustic equipment". It can be said that the birth of the underwater acoustic transducer marks the beginning of the development of underwater equipment technology, and its repeated technological progress is an important foundation and guarantee for the long-term development of underwater equipment. Compared with traditional single or multiple underwater ultrasonic probe devices, the phased array ultrasonic transducer can realize beam scanning, deflection and focusing in underwater equipment technology, and provides more powerful detection capability for determining the discontinuous shape, size and direction of underwater targets. The phased array is a combination of ultrasonic probe chips, which is obtained by distributing and arranging multiple piezoelectric chips. The phased array is mainly divided into three types: linear array, ring (circular) array and planar (two-dimensional rectangular) array. Among them, the linear array is more commonly used because the lead of the single array electrode of the linear array is easier to use, and the cost is obviously lower than that of other arrays, but the one-dimensional linear array can only focus on a sheet-shaped sound field, in addition, the one-dimensional ring (circular) array can only focus on a point-shaped sound field, and the preparation cost is high. The planar phased array can meet the back and forth conversion of sheet-shaped and point-shaped sound fields.

[0003] As a functional material, lead zirconate titanate piezoelectric ceramic (PZT) has been widely used by people. However, due to the high acoustic impedance of PZT pure piezoelectric ceramic, large transverse coupling when thickness mode resonance, narrow bandwidth and the difficulty in matching with water and human body and other media, it is difficult to apply lead zirconate titanate piezoelectric ceramic (PZT) to planar phased array ultrasonic transducers. In addition, when the array elements are densely arranged, the parasitic capacitance and inductive coupling effect between adjacent array elements are enhanced, which easily leads to mutual interference of the driving signals, so that the high-frequency transducer array elements are difficult to realize independent control. SUMMARY

[0004] The purpose of the present application is to provide a planar phased array ultrasonic transducer to solve the problems existing in the prior art, and to effectively apply lead zirconate titanate piezoelectric ceramic (PZT) to planar phased array ultrasonic transducers and realize independent control of the transducer array elements.

[0005] To achieve the above purpose, the present application provides the following scheme:

[0006] The application provides a planar phased array ultrasonic transducer, which comprises a 1-3 type piezoelectric composite plate, a common positive electrode panel and a flexible circuit board, the 1-3 type piezoelectric composite plate comprises a polymer frame and a plurality of PZT piezoelectric ceramic columns, all the PZT piezoelectric ceramic columns are arrayed and embedded in the polymer frame, one end of the PZT piezoelectric ceramic column is a positive electrode end, the other end of the PZT piezoelectric ceramic column is a negative electrode end, the common positive electrode panel is fixedly connected and electrically connected with the positive electrode end of each PZT piezoelectric ceramic column, the flexible circuit board is provided with a pad area and at least one pin area, a plurality of pads are fixedly arranged on the pad area, a plurality of pins are fixedly arranged on the pin area, all the pins, all the pads and the negative electrode ends of all the PZT piezoelectric ceramic columns are one-to-one corresponding, the pads are electrically connected with the pins, and the pads are fixedly connected and electrically connected with the negative electrode ends of the PZT piezoelectric ceramic columns.

[0007] Preferably, all the PZT piezoelectric ceramic columns are arranged in eight rows and eight columns.

[0008] Preferably, the flexible circuit board is provided with four branch parts, the four branch parts are uniformly arranged around the pad area, one end of each branch part away from the pad area is provided with one pin area, and sixteen pins are fixedly arranged on each pin area.

[0009] Preferably, the pads are welded with the negative electrode ends of the PZT piezoelectric ceramic columns, and a solder passing hole is formed in the center of the pad.

[0010] Preferably, the 1-3 type piezoelectric composite plate has a length of 19.5 mm, a width of 19.5 mm and a thickness of 3 mm, the PZT piezoelectric ceramic column has a length of 2 mm, a width of 2 mm and a thickness of 3 mm, the distance between any two adjacent PZT piezoelectric ceramic columns is 0.25 mm, the pad area has a length of 20 mm and a width of 20 mm, the branch part has a length of 40 mm and a width of 20 mm, the pin has a width of 0.8 mm, the pad has a diameter of 1 mm, and the solder passing hole has a diameter of 0.5 mm.

[0011] Preferably, the application further comprises a positive electrode lead wire, one end of the positive electrode lead wire is fixedly connected and electrically connected with the common positive electrode panel.

[0012] Preferably, the application further comprises a waterproof and sound-transparent matching layer, a hard supporting backing layer and a supporting outer frame, the waterproof and sound-transparent matching layer is fixedly connected with the common positive electrode panel, the hard supporting backing layer is fixedly connected with the pad area, the supporting outer frame is fixedly sleeved outside the waterproof and sound-transparent matching layer, the common positive electrode panel, the 1-3 type piezoelectric composite plate, the pad area and the hard supporting backing layer, and the pin area is arranged outside the supporting outer frame.

[0013] Preferably, the waterproof and sound-transmissive matching layer is a polyurethane layer.

[0014] Preferably, the hard support backing layer is a foam layer.

[0015] Preferably, the common positive electrode panel is a silver panel.

[0016] The present application has the following technical effects relative to the prior art:

[0017] The plane phased array ultrasonic transducer provided by the present application adopts a 1-3 type piezoelectric composite plate, suppresses the transverse vibration mode of the PZT piezoelectric ceramic column, strengthens the vibration in the thickness direction, and forms a plurality of transducer array elements of the plane phased array ultrasonic transducer on the 1-3 type piezoelectric composite plate, wherein the transducer array elements correspond to the PZT piezoelectric ceramic columns one by one, each transducer array element includes a PZT piezoelectric ceramic column and a polymer surrounding the PZT piezoelectric ceramic column, the positive electrode ends of the PZT piezoelectric ceramic columns are connected in parallel through a common positive electrode panel, the negative electrode ends of the PZT piezoelectric ceramic columns are led out through the pads and pins on the flexible circuit board, that is, each pin corresponds to a transducer array element, the PZT piezoelectric ceramic columns are used as ultrasonic excitation sources, and the PZT piezoelectric ceramic columns are individually controlled through the flexible circuit board, thereby achieving the effect of independent control of the transducer array elements. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0019] Figure 1 The structure explosion diagram of the plane phased array ultrasonic transducer provided by the present application;

[0020] Figure 2 The another direction schematic diagram of the plane phased array ultrasonic transducer in the present application; Figure 1

[0021] Figure 3 The structure packaging schematic diagram of the plane phased array ultrasonic transducer provided by the present application;

[0022] Figure 4 The 1-3 type piezoelectric composite plate schematic diagram in the plane phased array ultrasonic transducer provided by the present application;

[0023] Figure 5 The schematic diagram of a single array element;

[0024] ​Figure 6 A single array element finite element simulation data graph in the planar phased array ultrasonic transducer provided by the application;

[0025] Figure 7 A finite element simulation data graph of a PZT piezoelectric ceramic column in the planar phased array ultrasonic transducer provided by the application, with length*width*height=2*2*3mm;

[0026] Figure 8 A graph of the relationship between the thickness of the PZT piezoelectric ceramic column and the resonant frequency;

[0027] Figure 9 A test result graph when all array elements work simultaneously;

[0028] In the figure: 1, piezoelectric composite plate of type 1-3; 2, common positive electrode panel; 3, flexible circuit board; 4, polymer frame; 5, PZT piezoelectric ceramic column; 6, pad area; 7, pin area; 8, branch part; 9, support outer frame; 10, positive electrode lead; 11, waterproof sound-transparent matching layer; 12, hard support backing layer. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the application will be apparently and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0030] The purpose of the application is to provide a planar phased array ultrasonic transducer to solve the problems in the prior art, realize the effective application of lead zirconate titanate piezoelectric ceramic (PZT) in the planar phased array ultrasonic transducer, and realize the independent control of the transducer array elements.

[0031] To make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the application will be further described in detail below with reference to the drawings and specific embodiments.

[0032] As Figures 1 to 5As shown, the present application provides a planar phased array ultrasonic transducer, comprising a 1-3 type piezoelectric composite plate 1, a common positive electrode panel 2 and a flexible circuit board 3, the 1-3 type piezoelectric composite plate 1 comprises a polymer frame 4 and a plurality of PZT piezoelectric ceramic columns 5, all the PZT piezoelectric ceramic columns 5 are arrayed embedded in the polymer frame 4, one end of the PZT piezoelectric ceramic column 5 is a positive electrode end, the other end of the PZT piezoelectric ceramic column 5 is a negative electrode end, the common positive electrode panel 2 is fixedly connected and electrically connected with the positive electrode end of each PZT piezoelectric ceramic column 5, the flexible circuit board 3 has a pad area 6 and at least one pin area 7, the pad area 6 is fixedly provided with a plurality of pads, the pin area 7 is fixedly provided with a plurality of pins, all the pins, all the pads and the negative electrode end of all the PZT piezoelectric ceramic columns 5 are one-to-one corresponding, the pad is electrically connected with the pin, and the pad is fixedly connected and electrically connected with the negative electrode end of the PZT piezoelectric ceramic column 5.

[0033] The planar phased array ultrasonic transducer provided by the present application adopts the 1-3 type piezoelectric composite plate 1, suppresses the transverse vibration mode of the PZT piezoelectric ceramic column 5, strengthens the vibration in the thickness direction, and forms a plurality of transducer array elements of the planar phased array ultrasonic transducer on the 1-3 type piezoelectric composite plate 1, wherein the transducer array element corresponds to the PZT piezoelectric ceramic column 5 one-to-one, each transducer array element comprises the PZT piezoelectric ceramic column 5 and the polymer surrounding the PZT piezoelectric ceramic column 5, the positive electrode end of each PZT piezoelectric ceramic column 5 is connected in parallel through the common positive electrode panel 2, the negative electrode end of the PZT piezoelectric ceramic column 5 is led out through the pad and the pin on the flexible circuit board 3, that is, each pin corresponds to one transducer array element, each PZT piezoelectric ceramic column 5 is used as an ultrasonic excitation source, and each PZT piezoelectric ceramic column 5 is individually controlled through the flexible circuit board 3, thereby realizing the effect of independent control of the transducer array element, so that the planar phased array ultrasonic transducer provided by the present application realizes the effective application of lead zirconate titanate piezoelectric ceramic (PZT) in the planar phased array ultrasonic transducer, and realizes the independent control of the transducer array element.

[0034] Specifically, by adopting the 1-3 type piezoelectric composite plate 1 structure, a plurality of PZT piezoelectric ceramic columns 5 are arrayed embedded in the polymer frame 4, corresponding to form a plurality of transducer array elements, and the positive electrode end and the negative electrode end of each PZT piezoelectric ceramic column 5 are led out through the common positive electrode panel 2 and the flexible circuit board 3 respectively, thereby realizing the independent control of each transducer array element, thereby solving the problems in the prior art and meeting the design target of independent control of the high-frequency transducer array element.

[0035] The plane phased array ultrasonic transducer provided by the application has the advantages of high electromechanical coupling coefficient and low transverse crosstalk of the 1-3 type piezoelectric composite plate 1, which significantly improves the sensitivity and resolution of the transducer, and the precise circuit wiring capability of the flexible circuit board 3 further optimizes the beam forming precision of the phased array, so that the sound field control is more flexible, the combination of the 1-3 type piezoelectric composite plate 1 and the flexible circuit board 3 can realize wider bandwidth and lower sidelobe level, and meanwhile, the light and thin bendable characteristic of the flexible circuit board 3 is combined with the processability of the 1-3 type piezoelectric composite plate 1, so that the transducer can adapt to the curved surface conformal design while keeping the consistency of the array element spacing, the integrated structure effectively reduces the signal attenuation caused by the traditional hard circuit, and small size and light weight application can be realized through the high-density interconnection of the flexible circuit board 3.

[0036] In the embodiment, the polymer frame 4 adopts an epoxy resin 618 frame.

[0037] As an optional implementation manner of the embodiment, a piezoelectric ceramic column such as barium titanate (BaTiO3) or potassium sodium niobate {KNN, (K, Na)NbO3} can be used to replace the PZT piezoelectric ceramic column 5.

[0038] As a more preferred implementation manner of the embodiment, all the PZT piezoelectric ceramic columns 5 are arranged in eight rows and eight columns, that is, sixty-four transducer elements are obtained, and each transducer element is a corresponding PZT piezoelectric ceramic column 5 (piezoelectric phase) on the 1-3 type piezoelectric composite plate 1, which is adapted to the structural characteristics of the sensitive element of the plane phased array ultrasonic transducer; it should be noted that the number of rows and columns of all the PZT piezoelectric ceramic columns 5 can be adjusted according to actual use requirements.

[0039] As a more preferred implementation manner of the embodiment, the flexible circuit board 3 has four branch parts 8, the four branch parts 8 are uniformly arranged around the pad area 6, one end of each branch part 8 away from the pad area 6 is provided with a pin area 7, and sixteen pins are fixedly arranged on each pin area 7, which is simple in structure and convenient for manufacturing and leading out.

[0040] As a more preferred implementation manner of the embodiment, the pad is welded with the negative electrode end of the PZT piezoelectric ceramic column 5, and a solder through hole is formed at the center of the pad, so that the solder can penetrate to the negative electrode end surface of the PZT piezoelectric ceramic column 5 during welding, and the connection stability is strengthened.

[0041] As a more preferred embodiment of the present embodiment, the 1-3 type piezoelectric composite plate 1 has a length of 19.5 mm, a width of 19.5 mm, and a thickness of 3 mm; the PZT piezoelectric ceramic column 5 has a length of 2 mm, a width of 2 mm, and a thickness of 3 mm; the distance between any two adjacent PZT piezoelectric ceramic columns 5 is 0.25 mm; the pad area 6 has a length of 20 mm and a width of 20 mm; the branch part 8 has a length of 40 mm and a width of 20 mm; the pin has a width of 0.8 mm; the pad has a diameter of 1 mm; and the solder through hole has a diameter of 0.5 mm. It should be noted that the above dimensions can be adjusted according to actual use requirements.

[0042] Specifically, the present application adjusts the working frequency of the ultrasonic transducer by studying the thickness of the 1-3 type piezoelectric composite plate 1, thereby realizing the high-frequency working mode of the transducer. Figure 6 As shown in the simulation design using ANSYS finite element software, the structure size of the 1-3 type piezoelectric composite plate 1 is determined, a 1-3 type piezoelectric composite plate 1 structure with sixty-four elements is designed, and the resonance frequency of a single element of the 1-3 type piezoelectric composite plate 1 is simulated to be 480 kHz.

[0043] Regarding the structure design, simulation and calculation using ANSYS, the ANSYS finite element simulation software can accurately model, simulate and calculate the PZT piezoelectric ceramic column 5 in the 1-3 type piezoelectric composite plate 1 in different physical fields. By simulating and calculating the thickness resonance mode of the 1-3 type piezoelectric composite plate 1 in the thickness direction, the corresponding frequency of the PZT piezoelectric ceramic column 5 under high-frequency vibration is obtained. In order to meet the design requirements of the transducer at high frequency, the material of the PZT piezoelectric ceramic column 5 is PZT5-A. The length* width* height of the PZT piezoelectric ceramic column 5 is 2*2*3 mm, and the finite element simulation calculates the small cube with a side length of 0.5 mm. Figure 7 As shown in the simulation, within the calculation frequency scanning range of 100 kHz-1000 kHz, the resonance frequency of the PZT piezoelectric ceramic column 5 under this size is 671.5 kHz.

[0044] As shown in the simulation, within the calculation frequency scanning range of 100 kHz-1000 kHz, the resonance frequency of the PZT piezoelectric ceramic column 5 under this size is 671.5 kHz. Figure 8 In order to obtain the relationship between the thickness of the PZT piezoelectric ceramic column 5 and the resonance frequency under the thickness resonance mode, the finite element simulation is used to simulate the relationship curve of thickness and frequency with the length and width of 2 mm and the thickness from 1 mm to 20 mm with an interval of 1 mm. It is found that the thickness resonance frequency and the thickness of the PZT piezoelectric ceramic column 5 present a nonlinear relationship, and the smaller the thickness of the PZT piezoelectric ceramic column 5, the higher the resonance frequency.

[0045] Based on the structural characteristics of the sensitive elements of a planar phased array ultrasonic transducer, a 1-3 piezoelectric composite plate 1 with 64 array elements was designed. The dimensions of the 1-3 piezoelectric composite plate 1 are 19.5*19.5*3mm, and the dimensions of a single array element are 2.5*2.5*3mm. The thickness of the polymer phase is 0.25mm.

[0046] Simulating a single array element of a 1-3 piezoelectric composite plate 1 can reduce the computational complexity of the entire 1-3 piezoelectric composite plate 1. In the simulation, epoxy resin 618 was selected as the polymer phase material. This is due to the ease of curing of epoxy resin, which, after curing, is an excellent insulating material with high dielectric properties, resistance to surface leakage, and arcing. To investigate the effect of different PZT piezoelectric ceramic pillar 5 dimensions on the resonant frequency of a 3mm thick 1-3 piezoelectric composite plate 1, simulations were performed for PZT piezoelectric ceramic pillars 5 of the same thickness but different lengths and widths. The conductance curves, resonant frequencies, and resonant vibration states of single array elements were obtained for PZT piezoelectric ceramic pillars 5 with a thickness of 3mm and widths of 2.25mm, 2.0mm, 1.75mm, 1.5mm, 1.25mm, 1.0mm, 0.75mm, and 0.5mm, respectively. When the length and width of the PZT piezoelectric ceramic pillar 5 are 2mm, the resonance curve of a single element has a single peak, and its vibration mode only includes the thickness resonance mode. Furthermore, compared to the simulation of the PZT piezoelectric ceramic pillar 5, the polymer load can reduce the resonant frequency of the PZT piezoelectric ceramic pillar 5. When the length and width of the PZT piezoelectric ceramic pillar 5 are 1mm, the single element has two relatively large resonance peaks, with resonant frequencies of 444kHz and 508kHz, respectively. Observation of the vibration modes indicates that the thickness resonance mode is 444kHz.

[0047] As a more preferred implementation of this embodiment, the planar phased array ultrasonic transducer provided by the present invention also includes a positive electrode lead 10, one end of which is fixedly connected and electrically connected to the common positive electrode panel 2 to facilitate leading out the positive electrode end of each PZT piezoelectric ceramic column 5.

[0048] As a more preferred embodiment of the present embodiment, the planar phased array ultrasonic transducer provided by the present application further comprises a waterproof sound-transmitting matching layer 11, a hard supporting backing layer 12 and a supporting outer frame 9, the waterproof sound-transmitting matching layer 11 is fixedly connected with the common positive electrode panel 2, the hard supporting backing layer 12 is fixedly connected with the pad area 6, the supporting outer frame 9 is fixedly sleeved outside the waterproof sound-transmitting matching layer 11, the common positive electrode panel 2, the 1-3 type piezoelectric composite plate 1, the pad area 6 and the hard supporting backing layer 12, the pin area 7 is placed outside the supporting outer frame 9, waterproof and sound transmission are realized through the waterproof sound-transmitting matching layer 11, support to the common positive electrode panel 2, the 1-3 type piezoelectric composite plate 1 and the pad area 6 is realized through the hard supporting backing layer 12, and the waterproof sound-transmitting matching layer 11, the common positive electrode panel 2, the 1-3 type piezoelectric composite plate 1, the pad area 6 and the hard supporting backing layer 12 are fixed as a whole through the supporting outer frame 9.

[0049] As a more preferred embodiment of the present embodiment, the waterproof sound-transmitting matching layer 11 is a polyurethane layer, the density, sound speed and characteristic impedance of the polyurethane material are relatively close to those of water medium, which can better match with water, and the interface between the waterproof sound-transmitting matching layer 11 and water can reflect the ultrasonic waves generated by the vibration of the PZT piezoelectric ceramic column 5 back, in order to completely transmit the ultrasonic waves from the waterproof sound-transmitting matching layer 11, the theoretical basis for the design of the thickness of the waterproof sound-transmitting matching layer 11 is based on the matching full transmission theory of quarter wavelength integer multiple.

[0050] As a more preferred embodiment of the present embodiment, the hard supporting backing layer 12 is a foam layer, which is light in mass and has effective sound absorption effect, when the PZT piezoelectric ceramic column 5 is excited by an excitation signal, the PZT piezoelectric ceramic column 5 performs thickness direction (axial direction) vibration, sound waves are generated on the surface of the PZT piezoelectric ceramic column 5 and radiated to the hard supporting backing layer 12, the dense porous structure of the foam layer can effectively absorb the vibration radiation sound waves, and the foam plastic has very small density, which can reduce the weight of the transducer.

[0051] As a more preferred embodiment of the present embodiment, the common positive electrode panel 2 is a silver panel, the common positive electrode panel 2 is obtained by uniformly coating silver paste on the positive electrode end of each PZT piezoelectric ceramic column 5 and connecting into a thin layer.

[0052] The plane phased array ultrasonic transducer provided by the application is prepared by using a cutting filling method to prepare a 1-3 type piezoelectric composite plate 1, retaining the original electrode of the piezoelectric ceramic sheet and using the original electrode as the original electrode in the transducer array element, and welding and assembling the flexible circuit board 3 with the negative electrode end of each PZT piezoelectric ceramic column 5. Specifically, first, the piezoelectric ceramic sheet with a thickness of 3 mm is cut using a cutting machine, and the original electrode is retained, and then epoxy resin is filled and cured to prepare the 1-3 type piezoelectric composite plate 1; silver paste is uniformly applied to the positive electrode end of each PZT piezoelectric ceramic column 5 and connected into a thin layer to obtain a common positive electrode panel 2, and a positive electrode lead 10 is welded on the common positive electrode panel 2; the pads on the flexible circuit board 3 are aligned with the negative electrode end of the PZT piezoelectric ceramic column 5, and are welded with the original electrode retained after cutting; after welding is completed, a hard support backing layer 12 is bonded using silicone, and a support outer frame 9 is bonded and assembled, and the pin area 7 on the flexible circuit board 3 is led out of the support outer frame 9; finally, a quarter wavelength thickness of polyurethane sealant is filled, and after the polyurethane is cured, the preparation is completed.

[0053] After preparation is completed, an impedance analyzer is used to test the resonant frequency of each array element, and the curve of each array element has only one peak value; the resonant frequency points corresponding to the sixty-four array elements are counted to obtain a resonant frequency range of 415 kHz to 446.5 kHz; in simulation, the resonant frequency of a single array element is 480 kHz, and there is a deviation of nearly 30 kHz, which is caused by the load effect of the soldering tin points on the PZT piezoelectric ceramic column 5 during welding, and the waterproof sound transmission matching layer 11 also causes a load on the radiation surface of the PZT piezoelectric ceramic column 5 during packaging, thereby reducing the resonant frequency; the conductance values corresponding to the resonant frequency points of the sixty-four array elements are counted to obtain a conductance value distribution range of 1.13*10 -4 S to 1.71*10 -4 S; the flexible circuit board 3 has four branch parts 8, each branch part 8 corresponds to sixteen array elements, the sixteen array elements corresponding to each branch part 8 are connected in parallel, and the conductance curve is measured, as shown in Figure 9 , four conductance curve graphs are obtained, and each curve has only one peak value, and the resonant frequencies are 451 kHz, 451 kHz, 460 kHz and 460 kHz, respectively; then the sixty-four array elements are connected in parallel, and the resonant frequency is tested to be 460 kHz.

[0054] The resonant frequencies of the sixty-four array elements are between 415 kHz and 446.5 kHz, the resonant frequency of all array elements working simultaneously is 460 kHz, and the design goal of independent control of the high-frequency transducer array element is finally achieved.

[0055] The principles and implementation manners of the present application are described by using specific examples in the present application, and the above examples are only used for helping to understand the method of the present application and its core idea; meanwhile, for the general technical personnel in the art, according to the idea of the present application, the specific implementation manners and application ranges will be changed. In conclusion, the content of the present specification should not be understood as the limitation of the present application.

Claims

1. A planar phased array ultrasonic transducer, characterized in that: It includes a 1-3 type piezoelectric composite plate, a common positive electrode panel and a flexible circuit board. The 1-3 type piezoelectric composite plate includes a polymer frame and a plurality of PZT piezoelectric ceramic columns. All the PZT piezoelectric ceramic columns are embedded in the polymer frame in an array. One end of the PZT piezoelectric ceramic column is a positive electrode terminal, and the other end of the PZT piezoelectric ceramic column is a negative electrode terminal. The common positive electrode panel is fixedly connected and electrically connected to the positive electrode terminal of each PZT piezoelectric ceramic column. The flexible circuit board has a pad area and at least one pin area. The pad area is fixedly provided with a plurality of pads, and the pin area is fixedly provided with a plurality of pins. All the pins, all the pads and the negative electrode terminals of all the PZT piezoelectric ceramic columns correspond one to one. The pads are electrically connected to the pins, and the pads are fixedly connected and electrically connected to the negative electrode terminals of the PZT piezoelectric ceramic columns.

2. The planar phased array ultrasonic transducer according to claim 1, wherein: All the PZT piezoelectric ceramic columns are arranged in eight rows and eight columns.

3. The planar phased array ultrasonic transducer according to claim 2, wherein: The flexible circuit board has four branches, which are evenly arranged around the pad area. Each branch has a pin area on one end away from the pad area, and each pin area is fixed with sixteen pins.

4. The planar phased array ultrasonic transducer according to claim 3, wherein: The pad is welded to the negative electrode end of the PZT piezoelectric ceramic column, and a solder through hole is opened at the center of the pad.

5. The planar phased array ultrasonic transducer according to claim 4, characterized in that: The length of the 1-3 type piezoelectric composite plate is 19.5 mm, the width is 19.5 mm, and the thickness is 3 mm; the length of the PZT piezoelectric ceramic column is 2 mm, the width is 2 mm, and the thickness is 3 mm; the distance between any two adjacent PZT piezoelectric ceramic columns is 0.25 mm; the length of the pad area is 20 mm, and the width is 20 mm; the length of the branch part is 40 mm, and the width is 20 mm; the width of the pin is 0.8 mm; the diameter of the pad is 1 mm; and the diameter of the solder through hole is 0.5 mm.

6. The planar phased array ultrasonic transducer according to claim 1, wherein: A positive electrode lead is also included, one end of which is fixedly and electrically connected to the common positive electrode panel.

7. The planar phased array ultrasonic transducer according to claim 1, wherein: It also includes a waterproof and sound-transmitting matching layer, a rigid support backing layer and a support outer frame. The waterproof and sound-transmitting matching layer is fixedly connected to the common positive electrode panel, the rigid support backing layer is fixedly connected to the pad area, the support outer frame is fixedly sleeved on the outside of the waterproof and sound-transmitting matching layer, the common positive electrode panel, the 1-3 type piezoelectric composite plate, the pad area and the rigid support backing layer, and the pin area is placed outside the support outer frame.

8. The planar phased array ultrasonic transducer according to claim 7, characterized in that: The waterproof and sound-permeable matching layer is a polyurethane layer.

9. The planar phased array ultrasonic transducer according to claim 7, wherein: The hard supporting backing layer is a foam layer.

10. The planar phased array ultrasonic transducer according to claim 1, characterized in that: The common positive electrode panel is a silver panel.

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