CN108339727B - A high-frequency dual-beam directivity transducer and method of making the same - Google Patents

Abstract

The invention provides a high-frequency dual-beam directivity transducer and a manufacturing method thereof, wherein the transducer comprises a piezoelectric composite material (2) and two electrode wires (4); the piezoelectric composite material (2) 2) It has a ball-shaped structure. The ball-shaped structure is a hollow shape with openings at both ends, and is formed by bonding several piezoelectric ceramic small columns (7) cut into Positive and negative electrodes are plated on the inner and outer surfaces; one end of the two electrode wires (4) is welded to the positive and negative electrodes respectively, and the other ends of the two electrode wires (4) are drawn out from the transducer. The transducer prepared by using the piezoelectric ceramic composite material with the spherical frustum structure in the present invention can not only realize the dual beam directivity of the high-frequency transducer, but also have small fluctuations in the beam opening angle, and can meet the requirements of large power radiation requirements.

Description

A high-frequency dual-beam directivity transducer and method of making the same

technical field

The invention relates to the field of piezoelectric composite material transducers, in particular to a high-frequency dual-beam directivity transducer and a manufacturing method thereof.

Background technique

In airborne and underwater sound detection and imaging equipment, the performance of the transducer often affects the overall performance of the system. When detecting and imaging targets, not only long detection distance and high imaging resolution are often required, but also special directional beam requirements are sometimes required. Sometimes a transducer or array is required not only to be able to generate spherical waves, but also to have dual beam pointing characteristics to meet specific detection or imaging needs. For high-frequency and high-resolution imaging sonar or high-resolution detection equipment, high-power emission performance is often required. For traditional planar arrays, the emission beam width and emission sound source level are mutually constrained. That is, the wider the transmitting beam (the larger the imaging observation range), the smaller the effective radiation area of the array and the lower the sound source level (the closer the detection distance is), and the spherical transducer or the array is an effective solution to this problem. way.

For high-frequency spherical transducers or arrays, in addition to theoretical analysis and numerical calculation, it is more important to realize the design in the manufacturing process. Spherical transducers with a high frequency of several hundred kilohertz cannot be realized by the vibration frequency of the whole piezoelectric ceramic. In order to achieve the same equal amplitude vibration of the spherical surface, only the longitudinal vibration mode of the small piezoelectric vibrator can be used to form an integral spherical matrix array. to fulfill. If a single longitudinal vibration mode of a high-frequency piezoelectric vibrator is to be realized, a certain aspect ratio must be satisfied. According to the half-wavelength resonance theory, the higher the frequency, the smaller the resonance length of the vibrator, and the width is smaller than the length. Therefore, the higher the frequency, the smaller the pressure. The smaller the volume of the vibrator. If a small-volume piezoelectric vibrator table is to be formed, it is difficult to achieve by using a common manufacturing process, and a special process must be used to achieve it.

SUMMARY OF THE INVENTION

The purpose of the present invention is that, in view of the special requirements of the above-mentioned high-frequency spherical transducer and the realization process of the array, according to the experience of high-frequency transducer development and piezoelectric composite process preparation, the present invention provides a high-frequency dual-beam A directional transducer and a manufacturing method thereof, the core device of the transducer is a spherical table-shaped piezoelectric composite material, and an improved piezoelectric composite material preparation method is used to form a spherical table, and a high-frequency transducer prepared by using the spherical table-shaped piezoelectric composite material is used. The energizer has good spatial dual beam directivity.

In order to achieve the above purpose, the present invention provides a high-frequency dual-beam directivity transducer, comprising: a piezoelectric composite material and two electrode wires; the piezoelectric composite material has a ball-shaped structure, and the ball-shaped structure It is a hollow shape with openings at both ends, and is formed by bonding several piezoelectric ceramic small columns cut from a piezoelectric ceramic ring. The inner and outer surfaces of the ball-shaped structure are plated with positive and negative electrodes; one end of the two electrode lines Welded on the positive and negative electrodes respectively, and led out the other ends of the two electrode wires from the transducer.

As a further improvement of the above technical solution, it also includes a rigid polyurethane foam and a back plate; the inner surface of the ball table structure is attached and fixed on the top surface of the rigid polyurethane foam, and the back plate is fixed on the rigid polyurethane foam. The bottom surface; the polyurethane rigid foam and the ball-shaped piezoelectric composite material are arched, and can be bonded to the foam through 704 silica gel; the electrode wire runs through the polyurethane rigid foam and the backplane, and is led out from the bottom of the backplane .

As a further improvement of the above technical solution, the outer surface of the transducer is coated with polyurethane rubber, and the installed ball table-shaped piezoelectric composite material, foam and back plate can be covered by a pouring mold to form a transducer.

As a further improvement of the above technical solution, the radius of the ball-shaped structure is 80mm, and its corresponding two central angles are 130° and 50° respectively; the outer surface of the piezoelectric ceramic small column is square, and its size is 2.5 mm×2.5mm, the thickness of the piezoelectric ceramic small column is 3.6 mm, and the gap width of any two adjacent piezoelectric ceramic small columns is 0.5 mm.

As a further improvement of the above technical solution, the surface of the ball-shaped structure and the gap between any two adjacent piezoelectric ceramic small columns are coated with epoxy glue after vacuum treatment.

As a further improvement of the above technical solution, the positive and negative electrodes are nickel-plated positive electrodes and nickel-plated negative electrodes.

Based on the high-frequency dual-beam directional transducer with the above structure, the present invention also provides a method for manufacturing a high-frequency dual-beam directional transducer. The transducer manufacturing process includes: piezoelectric ceramic cutting, A ball-shaped piezoelectric ceramic material is formed by adhering a soft mucous membrane, infused with a hard polymer material, solidified and shaped, and then polished and plated with electrodes; the ball-shaped piezoelectric composite material is installed in a high-strength sound-absorbing foam, and finally the outer layer is poured with sound-transmitting polyurethane rubber. The production method specifically includes the following steps:

Step 1) Determine the diameter and height of the ball-shaped structure according to the design requirements, and determine the inner and outer diameters of the piezoelectric ceramic ring with the diameter and height, and determine the outer surface size and thickness of the piezoelectric ceramic small column according to the operating frequency;

Step 2) After the selected piezoelectric ceramic ring is cut according to the set specifications, a layer of soft film is adhered to the upper surface of the piezoelectric ceramic ring, so that all the piezoelectric ceramic columns are adhered to each other. integrated structure;

Step 3) Press the cut piezoelectric ceramic ring into a ball-shaped structure through a ball-table mold, and coat the surface of the ball-shaped structure and the gap between any two adjacent piezoelectric ceramic small columns after vacuum treatment. epoxy glue;

Step 4) Perform high temperature curing treatment on the ball table structure coated with epoxy glue, and take out the cured ball table structure from the ball table mold. After grinding, the inner and outer surfaces of the piezoelectric ceramic column are exposed. Nickel electrodes are plated on the inner and outer surfaces of the small column, and an electrode wire is welded to each of the two electrodes;

Step 5) Attach and fix the inner surface of the ball table structure to the top surface of the polyurethane rigid foam, and fix the back plate on the bottom surface of the polyurethane rigid foam, and pass the electrode wire through the polyurethane rigid foam and the back plate. Then, the outer surface of the transducer is coated with urethane rubber.

The advantages of a high-frequency dual-beam directivity transducer and a manufacturing method thereof of the present invention are:

The transducer prepared by using the piezoelectric ceramic composite material with the spherical frustum structure in the present invention can not only realize the dual beam directivity of the high-frequency transducer, but also have small fluctuations in the beam opening angle, and can meet the requirements of large To meet the requirements of power radiation, this spherical table-shaped piezoelectric composite material structure design mode adopts a single vibration mode of the small-pillar piezoelectric composite material, which can realize the equal amplitude and in-phase vibration of the required shape to obtain the maximum energy output.

Description of drawings

FIG. 1 is a schematic structural diagram of a high-frequency dual-beam directional transducer provided by the present invention.

FIG. 2 is a schematic view of the structure of the present invention after the piezoelectric ceramic ring is cut into piezoelectric ceramic small pillars.

FIG. 3 is a schematic structural diagram of the press-forming of the piezoelectric composite material of the spherical table-shaped structure in the present invention.

FIG. 4 is a schematic view of the structure of the piezoelectric composite material with the spherical frustum structure in the present invention after being plated with electrodes.

FIG. 5 is a simulation curve of the directivity of the transducer made of the piezoelectric composite material of the spherical table structure in the present invention.

reference number

1. Polyurethane rubber 2. Piezoelectric composite material 3. Polyurethane rigid foam

4. Electrode wire 5. Back plate 6. Soft mucosa

7. Piezoelectric ceramic small column 8. Ball table convex upper die 9. Nickel-plated negative electrode

10. Epoxy glue 11. Ball table concave lower die 12. Nickel-plated positive electrode

Detailed ways

A high-frequency dual-beam directivity transducer and a manufacturing method thereof according to the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

As shown in FIG. 1 , a high-frequency dual-beam directional transducer provided by the present invention includes a piezoelectric composite material 2 and two electrode wires 4; the piezoelectric composite material 2 has a ball-shaped structure, and the The spherical table-shaped structure is a hollow shape with openings at both ends, and is formed by bonding several piezoelectric ceramic small columns 7 cut from a piezoelectric ceramic ring (as shown in Figure 2). The inner and outer surfaces of the spherical table-shaped structure are plated. There are positive and negative electrodes; one end of the two electrode wires 4 is welded to the positive and negative electrodes respectively, and the other ends of the two electrode wires 4 are drawn out from the transducer.

Based on the transducer with the above structure, as shown in FIG. 1 , the transducer may further include a rigid polyurethane foam 3 and a back plate 5 ; On the top surface, the back plate 5 is fixed on the bottom surface of the rigid polyurethane foam 3 ; the electrode wires 4 penetrate through the rigid polyurethane foam 3 and the back plate 5 , and are led out from the bottom of the back plate 5 . In addition, the outer surface of the transducer is coated with urethane rubber 1 .

The piezoelectric composite material with the above-mentioned spherical table structure developed by the present invention can be composed of a plurality of piezoelectric ceramic small columns to form a flat matrix with holes in the middle, and then pressed by a mold to form a spherical table shape. The electric composite ball table can be made as large as it is, so it is not limited by the production volume, and has good piezoelectric properties, so that the high frequency ball table transducer and the small vibrator of the matrix made of the piezoelectric composite material all work in a single longitudinal vibration. Mode, high electromechanical conversion efficiency, large energy output, and can achieve high-power radiation output; the vibration of the small vibrator on the ball table can be approximately regarded as a point source vibration, which has a good equal-amplitude in-phase vibration effect. Since the table is in the shape of a circle, it can form a circle beam, that is, double beam performance can be achieved in the plane passing through the center of the ball. In practical applications, high-power transmission can be achieved by designing the diameter of the table and the height of the table according to requirements, and at the same time, dual beam directivity in the plane of the radiation center can be achieved.

The invention provides a transducer or a base array capable of realizing high frequency, high power and dual beam directivity by developing a piezoelectric composite material with a spherical table structure. According to the design requirements, determine the ball diameter and table height of the table, and then determine the inner and outer diameter of the piezoelectric ceramic ring according to the size of the table, and determine the size of the piezoelectric ceramic small column according to the frequency. Apply a soft mucous membrane, place it in a mold and press it into a ball table shape. The formed piezoelectric ball table is polished and plated with positive and negative electrodes to form a ball table piezoelectric composite material; the produced ball table piezoelectric composite material is installed in a pre-designed On the rigid foam, the electrode wires are drawn out. After the rigid foam is glued to the back plate, the sound-transmitting rubber coating is poured to form a high-frequency dual-beam directivity transducer.

Based on the transducer with the above structure, with reference to Figures 1-4, the present invention also provides a method for manufacturing a high-frequency dual-beam directional transducer, which specifically includes the following steps:

First, design the ball radius and table height of the table according to the operating frequency and the opening angle of the transducer. The working frequency is usually determined by the system. After the working frequency is determined, the wavelength can be determined according to the speed of sound, and the ratio of the size of the spherical transducer to the wavelength affects the directivity performance of the transducer. The difference between the two central angles corresponding to the upper and lower circles of the table is a key factor in determining the beam opening angle of the transducer or array. If the central angle corresponding to the upper circle of the table is too small, the two The beam opening angle is easy to interfere, and simulation calculation is required during design; and the larger the diameter of the ball where the table is located, the higher the table, and the higher the emission sensitivity and sound source level. In this embodiment, the working frequency of the transducer is 400 kHz, and the opening angle of each beam in the 400 kHz double beam is required to be greater than 30°. The radius of the ball where the ball-shaped piezoelectric element is calculated is 80 mm, and the two centers corresponding to the ball table are calculated. The angles are 130° and 50° respectively. According to the area of the ball table surface, that is, the area of the ball belt is equal to the area of the plane ring, and the diameter of the circle on the ball table is equal to the inner diameter of the ring, the outer diameter of the piezoelectric ceramic ring is determined to be 160mm. Its inner diameter is 62mm, and the thickness of the piezoelectric disc is determined to be 3.6mm according to the operating frequency. To achieve a single vibration mode of piezoelectric ceramics, the height of the piezoelectric ceramic column is theoretically greater than the width by more than 3.16 times. Here, the simulation calculation is carried out. According to the experimental test, the outer surface of the piezoelectric ceramic small column is square, its size is 2.5mm×2.5mm, and the slit of the piezoelectric ceramic ring cutting is 0.5mm.

Secondly, according to the requirements of the design and calculation, the piezoelectric ceramic ring is cut into several piezoelectric ceramic small columns 7. The piezoelectric ceramic ring is bonded to the glass by 502 glue, and then cut into 2.5mm × 2.5mm piezoelectric ceramic small columns. Column 7, the gap between the ceramics is 0.5mm, while ensuring that the piezoelectric ceramics are cut through. After the piezoelectric ceramic ring is cut into small columns, a layer of soft film is adhered on the upper surface to make all the piezoelectric ceramic small columns 7 form a whole, and the piezoelectric ceramic small columns 7 are removed from the glass by soaking in acetone , the piezoelectric ceramic small column array after removal is shown in Figure 2.

Once again, prepare the ball table forming mold, as shown in Figure 3, the mold includes the ball table convex upper mold 8 and the ball table concave lower mold 11, the mold needs to be cleaned and coated with release agent, and the piezoelectric ceramics bonded to the soft mucous membrane The small column array is placed in the ball table forming mold; high-hardness high-temperature epoxy filling glue is prepared. The epoxy glue 10 needs to be vacuumized during preparation, and the prepared epoxy glue 10 is poured into the ball table concave lower mold 11 respectively. And coated in the gap between the small columns of the ball table, the piezoelectric ceramic small column array coated with epoxy glue 10 is pressed by the convex upper mold of the ball table and then vacuumized to remove the air bubbles in the glue. According to the high temperature epoxy resin The curing temperature of the glue is 120 ° C for curing, and the curing is carried out for 4-5 hours.

Then, after the cured piezoelectric composite material 2 is demolded, the periphery and the surface of the piezoelectric composite material 2 are polished to remove excess epoxy glue 10, and the convex and concave surfaces of the ball-shaped structure are exposed to the small cylinder surface of piezoelectric ceramics, so that the Nickel electrodes can be plated on the piezoelectric ceramic pillars 7; nickel-plated positive electrodes 12 and nickel-plated negative electrodes 9 are respectively provided on the concave and convex surfaces of the piezoelectric ceramic pillars 7 through a nickel-plating process to form the final piezoelectric composite material , and its structure is shown in Figure 4.

Finally, install the piezoelectric composite material with the prepared ball table structure on the prefabricated ball table-shaped polyurethane rigid foam 3. The polyurethane rigid foam 3 can not only play a structural support role, but also achieve a sound absorption effect. Make the transducer have better energy output. 704 silicone rubber can be used to bond the piezoelectric composite material 2 and the polyurethane rigid foam 3. After welding the positive and negative leads of the piezoelectric composite 3. Bond the metal backboard 5 at the back. The polyurethane rigid foam 3 and the metal backboard 5 can be bonded with 914 glue. After the glue is cured, prepare to pour the sound-transmitting polyurethane rubber 1 for surrounding wrapping. According to the volume of the filling space and the density of the polyurethane rubber, calculate the required quality of the polyurethane rubber, pour the refined polyurethane rubber into the mold covered by the ball table transducer, wait for the potting glue to be completely cured, and remove it. The mold and the transducer are completed, and the transducer as shown in Figure 1 is obtained.

The ball-shaped high-frequency transducer prepared by the above method can realize dual beam directivity. The directivity simulation of the piezoelectric composite transducer with a 400k spherical frustum structure at the resonance point is shown in Figure 5. It can be seen from the figure that the beam of the transducer has a main beam in the directions of 45° and 315°, respectively. , the beam opening angle is 34°, and the fluctuation in the opening angle is very small.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the embodiments, those of ordinary skill in the art should understand that any modification or equivalent replacement of the technical solutions of the present invention will not depart from the spirit and scope of the technical solutions of the present invention, and should be included in the present invention. within the scope of the claims.

Claims (7)

1. A high-frequency dual-beam directivity transducer, characterized in that it comprises a piezoelectric composite material (2) and two electrode wires (4); the piezoelectric composite material (2) has a ball-shaped structure, so The spherical table-shaped structure is a hollow shape with openings at both ends, and is formed by bonding a plurality of piezoelectric ceramic small columns (7) cut from a piezoelectric ceramic ring, and the piezoelectric composite material (2) is formed by pressing a mold. A ball table type, the mold comprises: a ball table convex upper mold (8) and a ball table concave lower mold (11); a plurality of piezoelectric ceramic small columns (7) are assembled to form a plane matrix with holes in the middle; Positive and negative electrodes are plated on the inner and outer surfaces; one end of the two electrode wires (4) is welded to the positive and negative electrodes respectively, and the other ends of the two electrode wires (4) are drawn out from the transducer. 2. The high-frequency dual-beam directivity transducer according to claim 1, characterized in that, further comprising a rigid polyurethane foam (3) and a back plate (5); the inner surface of the ball-shaped structure is attached and Fixed on the top surface of the polyurethane rigid foam (3), the back plate (5) is fixed on the bottom surface of the polyurethane rigid foam (3); the electrode wire (4) penetrates through the polyurethane rigid foam (3) and the back plate (5), and lead out from the bottom of the back plate (5). 3. The high-frequency dual-beam directivity transducer according to claim 2, wherein the outer surface of the transducer is coated with polyurethane rubber (1). 4. The high-frequency dual-beam directivity transducer according to claim 1, wherein the radius of the spherical frustum-shaped structure is 80 mm, and its corresponding two central angles are 130° and 50°, respectively. The outer surface of the piezoelectric ceramic small column (7) is square, and its size is 2.5 mm × 2.5 mm, the thickness of the piezoelectric ceramic small column (7) is 3.6 mm, and any two adjacent piezoelectric ceramic small columns ( 7) The slit width is 0.5mm. 5 . The high-frequency dual-beam directional transducer according to claim 1 , wherein the surface of the ball-shaped structure and the gap between any two adjacent piezoelectric ceramic small pillars ( 7 ) are coated with 5 . Covered with vacuumed epoxy glue (10). 6. The high-frequency dual-beam directional transducer according to claim 1, wherein the positive and negative electrodes are nickel-plated positive electrodes (12) and nickel-plated negative electrodes (9). 7. The manufacturing method of the high-frequency dual-beam directional transducer according to one of claims 1-6, wherein the manufacturing method comprises: Step 1) Determine the diameter and height of the ball-shaped structure according to the design requirements, and use the diameter and height to determine the inner and outer diameters of the piezoelectric ceramic ring, and determine the outer surface size and thickness of the piezoelectric ceramic small column (7) according to the operating frequency. ; Step 2) After the selected piezoelectric ceramic ring is cut into the piezoelectric ceramic small column (7) according to the set specifications, a layer of soft mucous membrane (6) is adhered on the upper surface of the piezoelectric ceramic ring, so that all the Piezoelectric ceramic pillars (7) are bonded to form an integral structure; Step 3) Press the cut piezoelectric ceramic ring into a ball-shaped structure through a ball-table mold, and coat the surface of the ball-shaped structure and the gap between any two adjacent piezoelectric ceramic small columns (7). Epoxy glue (10) after vacuum treatment; Step 4) Perform high temperature curing treatment on the ball table structure coated with epoxy glue (10), and take out the cured ball table structure from the ball table mold, and expose the inside and outside of the piezoelectric ceramic small column (7) after grinding On the inner and outer surfaces of the piezoelectric ceramic small column (7), nickel electrodes are plated, and an electrode wire (4) is welded on each of the two electrodes; Step 5) Attach and fix the inner surface of the ball table structure to the top surface of the rigid polyurethane foam (3), and fix the back plate (5) on the bottom surface of the rigid polyurethane foam (3), and attach the electrode wire (4) After passing through between the rigid polyurethane foam (3) and the back plate (5), the outer surface of the transducer is coated with polyurethane rubber (1).

Images