A method for manufacturing a collinear ultrasonic sensor array based on a 3D printing model

Abstract

The application discloses a kind of based on 3D printing model's collinear ultrasonic sensor array preparation method, belong to ultrasonic sensor preparation field.The application includes: the processing method of piezoelectric ceramic array, signal lead wire is made and connection mode, acoustic attenuation material mold 3D printing, piezoelectric ceramic array element filling, packaging shell 3D printing and packaging method.Piezoelectric ceramic sheet is cut into multiple square array elements, respectively filled in 3D printed sound attenuation material mold that can reduce the sound field interference between array elements;Silver plating electrode includes lower electrode and upper electrode, respectively sputtering upper and lower piezoelectric array using magnetron sputtering technology method, form collinear electrode;Backing material uses non-conductive material;Matching layer is laid on piezoelectric array, to be used for acoustic impedance matching;Wiring port is used to be connected with signal lead wire, sensor packaging shell is prepared using 3D printing.The application simplifies the preparation of traditional large-scale ultrasonic sensor array, reduces the number of array element wiring.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultrasonic sensor preparation, in particular to a method for preparing a collinear ultrasonic sensor array based on a 3D printed model. BACKGROUND

[0002] Ultrasonic detection has the advantages of large detection depth, wide range, good directivity, accurate defect positioning, convenient application, low development cost, fast detection rate, easy on-site analysis, safe use, no harm to human body, etc. Therefore, the ultrasonic detection method has a wide application in many fields such as industrial manufacturing, medicine and national defense.

[0003] The ultrasonic sensor array is an array structure composed of multiple elements. The element geometry and geometry parameters can be adjusted according to actual needs to design different scale array structures. Such sensors have the characteristics of large number of elements, rich receiving information and high scanning efficiency. Combined with specific transmission timing and logic, different beam wave fronts can be formed to further improve the detection sensitivity and quantitative resolution, which is the development trend of current ultrasonic sensors. The traditional ultrasonic sensor array adopts a relatively fixed excitation mode, and the whole synchronous excitation and delay excitation mode is adopted during excitation, which is not conducive to the adjustment of the transmission aperture. At the same time, each element adopts an independent lead structure, which makes the sensor structure complex and increases the cost. SUMMARY

[0004] The purpose of the present application is to prepare a sensor array, which adopts a row-column collinear structure. With the addressing excitation technology, the excitation and reception of different regions of the array can be realized, further improving the detection flexibility and the quantitative accuracy of the detection.

[0005] The technical scheme adopted by the present application is: a method for preparing a collinear ultrasonic sensor array based on a 3D printed model, the sensor comprising: a piezoelectric array 101 made of PZT piezoelectric ceramic material by mechanical cutting, used to transmit and receive ultrasonic waves; a matching layer 102 laid on the top of the piezoelectric array, used to match the acoustic impedance between the piezoelectric elements and the measured material; a backing material 103 which is a non-conductive material, placed below the piezoelectric array, used to absorb the ultrasonic waves emitted backward by the elements; a sound attenuation material mold 104 formed by 3D printing technology, used to fill the cut elements and reduce the crosstalk between the piezoelectric elements; the electrodes are divided into upper electrodes and lower electrodes, both of which are silver materials, the lower electrode 105 is sputtered on the bottom of the piezoelectric array, and the upper electrode 106 is sputtered on the top of the piezoelectric array, used to realize the electrical connection between the elements; the first lead 107 and the second lead 108 are both copper core signal lines with shielding layers, used to connect with the ultrasonic sensor excitation circuit; the packaging shell 109 is prepared by 3D printing technology, used to package the sensor.

[0006] The method comprises the following steps:

[0007] Step 1, select a square piezoelectric ceramic sheet made of PZT material, the piezoelectric ceramic sheet is pre-polarized, and a silver electrode layer is laid;

[0008] Step 2, according to the PZT piezoelectric ceramic sheet described in step 1, a mechanical cutting technology is used to cut the piezoelectric ceramic sheet into a plurality of array elements with the same structure, and the array element structure and geometric parameters are determined by design. In the embodiment of the application, square array elements are used, the number of rows and columns in the array is the same, both are N, and an array composed of N 2 array elements;

[0009] Step 3, according to the array element structure and geometric parameters described in step 2, a 3D printing technology is used to prepare a sound attenuation material mold with N 2 holes, the height of the mold is equal to the height of the array, the holes are arranged in a square structure, the size is the same as the independent piezoelectric array element, and the spacing of the holes can be selected according to actual needs;

[0010] Step 4, according to the 3D printing mold described in step 3, the cut array element described in step 2 is placed in the sound attenuation material mold, and the array element is bonded with glue to ensure that the array element is fixed in the 3D mold;

[0011] Step 5, according to the piezoelectric array described in step 4, a silver electrode is sputtered above the array using a magnetron sputtering technology to form an upper electrode layer, and a silver electrode is sputtered below the array to form a lower electrode layer. The upper and lower electrode layers are characterized by being laid on the surface of the 3D printing mold part on which the array element is mounted, and forming the overall electrode layer on the upper and lower surfaces respectively;

[0012] Step 6, according to the upper and lower surface electrode layer structure sputtered in step 5, the upper electrode layer is cut into N rows with equal spacing to form an upper electrode, and the cut groove width is equal to the hole spacing of the 3D printing mold described in step 3; the lower electrode layer is cut into N columns with equal spacing to form a lower electrode, and the cut groove width is equal to the hole spacing of the 3D printing mold described in step 3. The array elements in the array form collinear row electrodes on the upper surface electrode and collinear column electrodes on the lower surface electrode, and the cut groove depth is equal to the thickness of the silver electrode layer;

[0013] Step 7, according to the piezoelectric array with cut electrodes described in step 6, prepare a backing material, the backing material is a non-conductive material, and the size can be determined according to the size of the array;

[0014] Step 8, according to the backing material described in step 7, the piezoelectric array is adhered to the backing material with non-conductive glue;

[0015] Step 9, according to the piezoelectric array of the adhesive backing material described in step 8, prepare the matching layer, the matching layer material can adopt the conventional ultrasonic sensor matching layer material;

[0016] Step 10, according to the piezoelectric array described in step 9, weld the electrode lead, a total of 2N, the electrode lead is a copper wire with a shielding layer, used to realize the electrical signal connection of the sensor;

[0017] Step 11, according to the piezoelectric array with connected electrode lead described in step 10, print the sensor shell by using 3D printing technology, and put the piezoelectric array into the shell;

[0018] Step 12, according to the piezoelectric array put into the shell described in step 11, fill the gap with sound attenuation material, used to reduce the mutual interference of the piezoelectric elements;

[0019] Step 13, according to the sensor described in step 12, cover the top cover of the shell, and the preparation is completed.

[0020] The beneficial effects of the present application are:

[0021] The conventional ultrasonic sensor array adopts a relatively fixed excitation mode, and adopts whole synchronous excitation and delay excitation mode during excitation, which is not conducive to the adjustment of the transmitting aperture, and meanwhile, each array element adopts an independent lead structure, so that the sensor structure is complex and the cost is increased. The sensor array of the present application adopts a 3D printing model as the carrier of the array element, the number of array elements can be adjusted according to actual needs, the collinear row and column electrodes are made on the upper and lower surfaces of the sensor array, which facilitates addressing and excitation, and at the same time, cooperating with different excitation rules, the transmitting aperture and receiving aperture can be easily adjusted, the number of array element leads is greatly reduced, the anti-interference ability of the array element is improved, and the present application can provide beneficial reference for subsequent intelligent ultrasonic sensor development. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a front structure schematic diagram of the ultrasonic array sensor in the embodiment of the present application;

[0023] Figure 2 It is a front view cross-sectional schematic diagram of the ultrasonic array sensor in the embodiment of the present application;

[0024] Figure 3 It is a right view cross-sectional schematic diagram of the ultrasonic array sensor in the embodiment of the present application;

[0025] Figure 4 It is a flow chart of the preparation method of the ultrasonic array sensor in the embodiment of the present application;

[0026] Figure 5 It is a process flow schematic diagram of the preparation method of the ultrasonic array sensor in the embodiment of the present application, wherein, Figure 5Fig. 1(a) is a schematic diagram of a piezoelectric ceramic sheet to be processed, Figure 5 Fig. 1(b) is a schematic diagram of a piezoelectric array after mechanical cutting, Figure 5 Fig. 1(c) is a schematic diagram of a 3D-printed sound-attenuating material mold, Figure 5 Fig. 1(d) is a schematic diagram of placing the piezoelectric array into the 3D-printed sound-attenuating material mold, Figure 5 Fig. 1(e) is a schematic diagram of sputtering a lower electrode, Figure 5 Fig. 1(f) is a schematic diagram of sputtering an upper electrode, Figure 5 Fig. 1(g) is a schematic diagram of sputtering the lower electrode and the upper electrode, Figure 5 Fig. 1(h) is a schematic diagram of bonding a backing material, Figure 5 Fig. 1(i) is a schematic diagram of bonding a matching layer, Figure 5 Fig. 1(j) is a schematic diagram of connecting electrode leads, Figure 1 Fig. 1(k) is a schematic diagram of a fully assembled sensor. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions of the present application are further described below in combination with the drawings and examples. The present application takes a two-dimensional surface array with an array of 32x32 and a sensor operating frequency of 1MHz as an example to specifically describe the processing technology of the ultrasonic array sensor probe. The size and gap of the array elements can also be specifically selected according to needs. It should be understood that the specific examples described herein are only used to explain the present application and not to limit the present application.

[0028] The specific steps for implementing the present application are as follows:

[0029] A collinear ultrasonic sensor array based on a 3D-printed model, the structure of which is shown in Figure 2 . Figure 3 and Figure 1 are divided into Figure 4 transverse and longitudinal cross-sectional views, which can show the internal structure of the sensor array and the lead connection method. It includes a piezoelectric array 101, a matching layer 102, a backing material 103, a sound-attenuating material mold 104, a lower electrode 105, an upper electrode 106, a first lead 107, a second lead 108, and a packaging shell 109.

[0030] The preparation process flow chart is shown in Figure 5 , ​ is a schematic diagram of the structural changes of the sensor array after each process step. Specifically, the following steps are included:

[0031] Step 1, select a square piezoelectric ceramic sheet made of PZT material, the piezoelectric ceramic sheet is polarized and coated with a silver electrode layer, the side length is 79.5mm, and the thickness is 2mm;

[0032] Step 2, according to the PZT piezoelectric ceramic sheet described in step 1, using high-precision mechanical cutting technology, taking a 32x32 array as an example, the piezoelectric ceramic sheet is cut into 1024 independent piezoelectric array elements;

[0033] Step 3, according to the cut array element described in step 2, using 3D printing technology, an acoustic attenuation material mold with 1024 holes in the middle is prepared, the height of the mold is 2mm, the side length of each hole is 2mm, and the depth is 2mm;

[0034] Step 4, according to the 3D printing forming mold described in step 3, the cut array element described in step 2 is placed into the acoustic attenuation material mold;

[0035] Step 5, according to the piezoelectric array described in step 4, using magnetron sputtering technology, silver electrodes are sputtered above the array as the upper electrode layer, and silver electrodes are sputtered below the array in a direction perpendicular to the sputtering above as the lower electrode layer, the thickness of the silver electrode is 100μm;

[0036] Step 6, according to the sputtered electrode array described in step 5, the upper electrode is cut into 32 rows of equal intervals, and the lower electrode is cut into 32 columns of equal intervals, the cutting groove width is 0.5mm, and the width of each row or each column is equal to the side length of a single piezoelectric array element;

[0037] Step 7, according to the cut electrode piezoelectric array described in step 6, prepare the backing material, the backing material is a non-conductive material, the side length is 79.5mm, and the thickness is 10mm;

[0038] Step 8, according to the backing material described in step 7, the piezoelectric array is adhered to the backing material with non-conductive glue;

[0039] Step 9, according to the piezoelectric array with backing material described in step 8, prepare the matching layer, which can be the same as the matching layer of a common ultrasonic array sensor;

[0040] Step 10, according to the piezoelectric array described in step 9, weld 64 electrode leads, the electrode leads are copper wires with shielding layer, used to realize the connection between the sensor probe and the excitation circuit;

[0041] Step 11, according to the piezoelectric array with connected electrode leads described in step 10, using 3D printing technology, print the sensor shell, and put the piezoelectric array into the shell;

[0042] Step 12, according to the piezoelectric array placed in the shell described in step 11, fill the gap with acoustic attenuation material to reduce the mutual interference of piezoelectric array elements;

[0043] Step 13, according to the sensor probe described in step 12, cover the top cover of the shell, and the preparation is completed.

[0044] The piezoelectric ceramic sheet in step 1 can be replaced by PZT-5H material; the size of the piezoelectric ceramic sheet is determined according to the needs.

[0045] The mechanical cutting technology used in step 2, the size and shape of the piezoelectric array element after cutting are consistent.

[0046] The 3D printing technology is used in step 3 to prepare the whole acoustic attenuation material mold, and it is necessary to ensure that there is no air bubble in the acoustic attenuation material so that the performance of the acoustic attenuation material is not affected.

[0047] The 3D printing technology is used in step 3 to prepare the whole acoustic attenuation material mold, and the mold has N 2 holes, and the size of each hole is the same as the size of the independent piezoelectric array element.

[0048] In step 4, when the piezoelectric ceramic sheet is placed in the acoustic attenuation material mold, it is necessary to ensure the flatness of the piezoelectric array element.

[0049] The sputtered electrode in step 5 should not be too thick, and the direction of the upper electrode and the lower electrode is perpendicular to each other, so that the lower electrode connects each column of piezoelectric array elements, and the upper electrode connects each row of piezoelectric array elements.

[0050] In step 6, when cutting the sputtered electrode, the slot width is equal to the interval of each row or each column of piezoelectric array elements, and the 3D printed acoustic attenuation material in step 3 cannot be cut;

[0051] The backing material in step 7 is a non-conductive material that can absorb the ultrasonic waves emitted downward by the piezoelectric array element;

[0052] The matching layer material in step 9 can be the same as the matching layer of the commonly used ultrasonic array sensor;

[0053] In step 10, the electrode lead wire is welded, and there are 2N electrode lead wires.

[0054] In summary, the technical scheme of the present application comprises a piezoelectric ceramic array processing method, a signal lead manufacturing and connecting method, a sound attenuation material mold 3D printing, a piezoelectric ceramic array element filling, a packaging shell 3D printing and a packaging method. The piezoelectric ceramic sheet is cut into multiple square array elements, which are filled in the 3D printed sound attenuation material mold, and the sound attenuation material mold has the function of reducing the sound field interference between the array elements. The silver-plated electrode includes a lower electrode and an upper electrode, and the magnetron sputtering technology is used to sputter the upper and lower parts of the piezoelectric array respectively to form a collinear electrode for realizing the electrical connection of the piezoelectric array elements in different areas. The backing material is made of non-conductive material, which can absorb the back emission sound waves of the piezoelectric array and reduce the sound wave reflection interference. The matching layer is laid on the upper part of the piezoelectric array for sound impedance matching. The wiring port is used to connect with the signal lead. The sensor packaging shell is prepared by 3D printing to package the sensor. The present application simplifies the preparation method of the traditional large-scale ultrasonic sensor array, the collinear structure reduces the number of array element wiring, and the sensor array can be used for addressing and exciting occasions, and the transmitting aperture and receiving aperture can be controlled. The sensor array in the present application can be made into different scale array structures according to the needs, the collinear structure makes the excitation and signal receiving mode of the array elements more flexible, can effectively reduce the number of signal leads and the sound field mutual interference between the array elements. The PZT piezoelectric material is used, which can meet the needs of transmitting sound energy in industrial detection. The sensor array can not only be used for traditional phased array detection, but also can be used for dividing the functions of the array element area, making the signal excitation more flexible, and further expanding the application range of the ultrasonic sensor.

[0055] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0056] Although the embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A co-linear ultrasound sensor array based on a 3D printed model, characterized by, Comprise: piezoelectric array (101), composed of multiple piezoelectric elements made of PZT piezoelectric ceramic material mechanically cut, used to emit and receive ultrasonic waves; matching layer (102), laid on the top of the piezoelectric array, used to match the acoustic impedance between the piezoelectric array and the measured material; backing material (103), which is a non-conductive material, is placed below the piezoelectric array, used to absorb the ultrasonic waves emitted by the array element backward; acoustic attenuation material mold (104), formed by 3D printing technology, used to fill the cut piezoelectric elements, and has the effect of reducing the cross talk between the piezoelectric elements; electrode is divided into upper electrode and lower electrode, both are silver material, the lower electrode (105) sputtering on the bottom of the piezoelectric array, the upper electrode (106) sputtering on the top of the piezoelectric array, used to realize the electrical connection between each element; the first lead (107) and the second lead (108), both are copper core signal line with shielding layer, used to connect with the ultrasonic sensor excitation circuit; packaging shell (109), prepared by 3D printing technology, used to package the sensor.

2. A method of manufacturing a co-linear ultrasonic sensor array based on a 3D printed model according to claim 1, characterized in that, Comprise the following steps: step 1, select the square piezoelectric ceramic sheet made of PZT material, the piezoelectric ceramic sheet is pre-polarized, and the silver electrode layer is laid; Step 2, according to the piezoelectric ceramic sheet described in step 1, the piezoelectric ceramic sheet is cut into a plurality of elements with the same structure by using a mechanical cutting technique, and the element structure and geometric parameters are determined by design; when a square element is used, the number of rows and columns of elements in the array is the same, both are N, forming a planar array composed of N 2 elements. Step 3, according to the array element structure and geometric parameters described in step 2, using 3D printing technology, prepare the sound attenuation material mold with N 2 holes, the height of the mold is equal to the height of the array, the holes are arranged in a square structure, the size is the same as the independent piezoelectric element, and the spacing of the holes is selected according to actual needs; step 4, according to the 3D printing forming mold of step 3, the cut element of step 2 is placed in the acoustic attenuation material mold, and the element is bonded with glue to ensure the position of the element in the 3D mold; step 5, according to the piezoelectric array of step 4, the silver electrode is sputtered on the array by magnetron sputtering technology, forming the upper electrode layer, and the silver electrode is sputtered below the array, forming the lower electrode layer, the upper and lower electrode layers are laid on the upper surface and lower surface of the 3D printing forming mold part respectively, forming the upper and lower surface of the whole electrode layer respectively; step 6, according to the upper and lower surface of the whole electrode layer in step 5, the upper electrode layer is cut into N rows with equal interval, forming the upper electrode, and the cutting slot width is equal to the hole interval of the 3D printing mold in step 3; the lower electrode layer is cut into N columns with equal interval, forming the lower electrode, and the cutting slot width is equal to the hole interval of the 3D printing mold in step 3, the elements in the array form collinear row electrodes on the upper surface electrode and collinear column electrodes on the lower surface electrode, and the cutting slot depth is equal to the thickness of the silver electrode layer; step 7, according to the piezoelectric array with cut electrode in step 6, prepare the backing material, which is a non-conductive material, the backing material can absorb the ultrasonic waves emitted downward by the piezoelectric element, and the size of the backing material can be determined according to the size of the array; step 8, according to the backing material in step 7, the piezoelectric array is bonded to the non-conductive adhesive on the backing material; step 9, according to the piezoelectric array with adhesive backing material in step 8, prepare the matching layer, the matching layer material adopts the conventional ultrasonic sensor matching layer material; step 10, according to the piezoelectric array in step 9, weld the electrode lead, the welded electrode lead is 2N, and the electrode lead is copper wire with shielding layer, used to realize the electrical signal connection of the sensor; Step 11, according to the piezoelectric array connected electrode lead described in step 10, using 3D printing technology, printing sensor shell, piezoelectric array into the shell; Step 12, according to the piezoelectric array described in step 11 into the shell, fill the gap with sound attenuation material, to reduce the mutual interference of piezoelectric elements; Step 13, according to the sensor described in step 12, cover the shell top cover, preparation is completed.

3. The method of claim 2, wherein, The piezoelectric ceramic sheet in step 1 is PZT-5H material; the size of the piezoelectric ceramic sheet is determined according to the need.

4. The method of claim 2, wherein, The mechanical cutting technology used in step 2, the size and shape of the piezoelectric array after cutting are consistent.

5. The method of claim 2, wherein, The 3D printing technology is used in step 3 to prepare the whole sound attenuation material mold, which needs to ensure that there is no bubble in the sound attenuation material so that the performance of the sound attenuation material is not affected.

6. The method of claim 2, wherein, In step 3, a 3D printing technique is used to prepare a monolithic acoustic attenuation material mold, which has N 2 holes with the same size as the individual piezoelectric elements.

7. The method of claim 2, wherein, In step 4, when the piezoelectric array is put into the sound attenuation material mold, the flatness of the piezoelectric array needs to be ensured.

8. The method of claim 2, wherein, The sputtered electrode in step 5 should not be too thick, and the direction of the upper electrode and the lower electrode should be perpendicular to each other, so that the lower electrode connects each column of piezoelectric elements and the upper electrode connects each row of piezoelectric elements.

9. The method of claim 2, wherein, In step 6, when cutting the sputtered electrode, the width of the cutting groove is equal to the interval of each row or each column of piezoelectric elements, and the 3D printed sound attenuation material mold in step 3 cannot be cut.

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