A high-frequency spherical piezoelectric element and its preparation method

Abstract

The present invention discloses a high-frequency spherical piezoelectric element and a preparation method thereof, wherein the high-frequency spherical piezoelectric element comprises a piezoelectric material sphere, the piezoelectric material sphere comprises a plurality of piezoelectric composite rings with equal surface widths arranged in sequence from top to bottom, the piezoelectric composite rings are divided into a plurality of piezoelectric array elements along the circumferential direction, a polymer or vibration isolation and decoupling material pad is arranged between two adjacent piezoelectric composite rings, and the gap between two adjacent piezoelectric array elements is filled with a polymer. The piezoelectric element is formed by a graded division and cutting method and then assembled into components, which solves the problem that current conventional high-frequency transducer technology cannot process large-sized spherical piezoelectric elements. A transducer with horizontal omnidirectionality and vertical large opening angle can be produced in the frequency band above 100kHz, and the directivity fluctuation of the transducer is very small.

Description

Technical Field

[0001] The present invention relates to the technical field of transducer manufacturing, and in particular to a high-frequency spherical piezoelectric element and a preparation method thereof. Background Art

[0002] The field of underwater high-frequency imaging sonar detection is limited by high-frequency transducer technology. Currently, it can only achieve horizontal omnidirectionality and a very small vertical coverage range in waters. In particular, the higher the detection frequency or the greater the required sound source level, the smaller the vertical opening angle, and of course the smaller the detection range that can be covered, which seriously restricts the development of high-frequency imaging sonar in the field of large-scale detection. Later, scientific and technological personnel took measures to address the above problems and designed a flat-plate imaging sonar in the blind spot (axial direction) of the cylindrical high-frequency transducer. When this type of imaging sonar is placed near the water surface, it can detect both the horizontal direction and the direction directly below the sonar. However, when the detection frequency is relatively high, there will still be a blind spot between the horizontal direction and the vertical direction directly below.

[0003] In the application of receiving hydrophones or transmitting transducers for underwater self-propelled acoustic fuze targets, full spatial coverage is required, or at least omnidirectional horizontally and with wide vertical angle coverage. However, there are currently no transducers that can provide wide angle coverage in the range of several hundred kilohertz. Summary of the Invention

[0004] In order to address the deficiencies in the prior art, the inventors provide a high-frequency spherical piezoelectric element and a method for preparing the same. The prepared piezoelectric element, when used as the core component of a high-frequency transducer above 100kHz, can achieve horizontal omnidirectionality, vertical wide-angle directivity, and even full-space directivity; and the directivity has little fluctuation and the sound source level is relatively high.

[0005] According to a first aspect, the present invention provides a high-frequency spherical piezoelectric element, comprising a piezoelectric material sphere, wherein the piezoelectric material sphere comprises a plurality of piezoelectric composite rings with equal surface widths arranged in sequence from top to bottom, wherein the piezoelectric composite rings are divided into a plurality of piezoelectric array elements along the circumferential direction, and the piezoelectric composite rings are assembled into a spherical piezoelectric element with a spherical backing as a base; a polymer or vibration isolation and decoupling material pad is arranged between two adjacent piezoelectric composite rings, and the gap between two adjacent piezoelectric array elements is filled with a polymer.

[0006] Furthermore, the height and radial thickness of the piezoelectric array element are the same.

[0007] Furthermore, a hole with a diameter of not less than 10 mm is opened on the top of the piezoelectric material sphere.

[0008] Furthermore, the inner and outer surfaces of the piezoelectric composite ring are plated with a positive electrode and a negative electrode respectively, and the positive electrode and the negative electrode of each piezoelectric composite ring are respectively welded together in parallel.

[0009] Furthermore, the polymer is epoxy resin, silicone rubber, polyurethane or phenolic resin.

[0010] According to a second aspect, the present invention further provides a method for preparing a high-frequency spherical piezoelectric element, comprising the following steps:

[0011] Cutting step: using a spherical or two hemispherical piezoelectric materials as a base material, cutting it into a plurality of piezoelectric composite rings with equal surface widths with the center of the sphere as the cutting circle center, and then cutting a plurality of slits on the piezoelectric composite ring at equal intervals along the circumference of the piezoelectric composite ring to divide the piezoelectric composite ring into a plurality of piezoelectric array elements;

[0012] One-time filling step: using a mold to fill the gaps between adjacent piezoelectric elements with polymer;

[0013] Polishing step: After the polymer is cured, the electrode surfaces on the inner and outer surfaces of the piezoelectric composite ring are polished off so that the height of the piezoelectric array element is the same as the radial thickness;

[0014] Electrode plating step: plating electrodes on the inner and outer surfaces of the piezoelectric composite ring, which serve as the positive electrode and negative electrode of the piezoelectric composite ring respectively;

[0015] Molding steps: placing the piezoelectric composite rings into the set mold in sequence, using the spherical backing as the base, filling the space between two adjacent piezoelectric composite rings with polymer, and assembling the piezoelectric composite rings into a spherical piezoelectric element; or placing the piezoelectric composite rings and the vibration isolation and decoupling material pads into the set mold at intervals, using the spherical backing as the base, bonding the vibration isolation and decoupling material pads and the piezoelectric composite rings together, and thus assembling the spherical piezoelectric element;

[0016] Welding steps: After forming, the positive and negative electrodes of each piezoelectric composite ring are welded together in parallel.

[0017] Furthermore, in the cutting step, the width of the cutting gap is no greater than 1 mm.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] (1) The piezoelectric element provided by the present invention is formed by a graded cutting method and then assembled into components, which solves the problem that the current conventional high-frequency transducer technology cannot process large-sized spherical piezoelectric elements.

[0020] (2) When the piezoelectric element is used as the core component of a high-frequency transducer, it can achieve horizontal omnidirectionality, vertical wide-angle directivity, and even full-space directivity; and the directivity has small fluctuations and the sound source level is relatively high.

[0021] (3) This method is relatively simple to implement and has low production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1Schematic diagram of the structure of the high-frequency spherical piezoelectric element in Example 1 of the present invention;

[0023] Figure 2 1 is an exploded view of the high-frequency spherical piezoelectric element in Example 1 of the present invention;

[0024] Figure 3 Schematic diagram of the structure of the piezoelectric composite ring in Example 1 of the present invention;

[0025] Figure 4 This is a voltage response diagram of the piezoelectric high-frequency spherical transducer in Example 1 of the present invention;

[0026] Figure 5 This is the directivity diagram of the piezoelectric high-frequency spherical transducer at 350 kHz in Example 1 of the present invention.

[0027] Reference numerals:

[0028] 1-piezoelectric material sphere; 2-piezoelectric composite ring; 21-piezoelectric array element; 22-slit; 3-hole; 4-polymer. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below through specific embodiments with reference to the accompanying drawings.

[0030] Example 1

[0031] like Figure 1-2 As shown, the present invention provides a high-frequency spherical piezoelectric element comprising a piezoelectric material sphere made of a 1-3 type piezoelectric composite material. A hole with a diameter of no less than 10 mm is formed on the top of the piezoelectric material sphere. The piezoelectric material sphere comprises a plurality of piezoelectric composite rings of equal surface width arranged sequentially from top to bottom. The piezoelectric composite rings are circumferentially divided into a plurality of piezoelectric array elements of equal height and radial thickness. A polymer or vibration isolation and decoupling material pad is disposed between adjacent piezoelectric composite rings. The gap between adjacent piezoelectric array elements is filled with a polymer. The polymer is a high molecular weight polymer such as epoxy resin, silicone rubber, polyurethane, or phenolic resin.

[0032] Specifically, the preparation process of the high-frequency spherical piezoelectric element is as follows:

[0033] Cutting steps: Use a spherical or two hemispherical piezoelectric materials with a hole on the top as the substrate (the size of the hole is determined according to the size of the beam opening angle, and the diameter of the hole is not less than 10mm), use the center of the sphere as the cutting center, and use a precision cutting machine to cut it into multiple piezoelectric composite rings with equal surface width; then use each piezoelectric composite ring as the substrate, cut a number of gaps in the piezoelectric composite ring at the same spacing (the sum of the particle size and the gap width is the spacing) along the circumference of the piezoelectric composite ring, and divide the piezoelectric composite ring into multiple piezoelectric array elements. The width of the cutting gap is not more than 1mm, and the gap depth is not less than the thickness of the high-frequency spherical piezoelectric element.

[0034] The primary filling step involves using a mold to fill the gaps between adjacent piezoelectric elements with polymer. The polymer must be vacuumed before and during the polymer infusion process to ensure that all gaps are filled with polymer, thereby improving the consistency of the piezoelectric composite's performance.

[0035] Polishing step: After the polymer is cured, the electrode surfaces on the inner and outer surfaces of the piezoelectric composite ring are polished off so that the height of the piezoelectric array element is the same as the radial thickness.

[0036] Electrode plating step: Electrodes are plated on the inner and outer surfaces of the piezoelectric composite ring, which serve as the positive electrode and the negative electrode of the piezoelectric composite ring respectively.

[0037] Molding steps: Place the piezoelectric composite rings into the set mold in sequence (the set mold has a slot for accurately positioning each piezoelectric composite ring), use the spherical backing as the base, fill the space between two adjacent piezoelectric composite rings with polymer, and assemble the piezoelectric composite rings into a spherical piezoelectric element; or place the piezoelectric composite ring and the vibration isolation and decoupling material pad into the set mold at intervals, use the spherical backing as the base, and bond the vibration isolation and decoupling material pad and the piezoelectric composite ring together, thereby assembling them into a spherical piezoelectric element.

[0038] If two hemispherical piezoelectric materials are used as the substrate for cutting, a vibration isolation and decoupling pad with the same thickness as the width of the gap between the ceramic particles needs to be placed between the two hemispherical piezoelectric elements and glued together to form a high-frequency spherical piezoelectric element.

[0039] Welding steps: After forming, the positive and negative electrodes of each piezoelectric composite ring are welded together in parallel.

[0040] The performance of the transducer made of the high-frequency spherical piezoelectric element was tested. The voltage response of the transducer in water was as follows: Figure 3 As shown, the directivity of the piezoelectric high-frequency spherical transducer at 350kHz is as follows Figure 4 As shown, each grid in the figure is 3dB. The result shows that the directivity fluctuation is 4.3dB.

[0041] The test results show that the high-frequency transducer made of the piezoelectric element provided by the present invention achieves ultra-large space or full-space directional coverage with small directional fluctuations, which is of great significance for high-frequency image sonar detection and high-frequency acoustic fuze simulation.

[0042] The above examples are used to illustrate the present invention, which are only used to help understand the present invention and are not intended to limit the present invention. Those skilled in the art can make several simple deductions, modifications or substitutions based on the concept of the present invention.

Claims

1. A high-frequency spherical piezoelectric element, characterized in that: The piezoelectric material sphere comprises a plurality of piezoelectric composite rings of equal surface width arranged sequentially from top to bottom. The piezoelectric composite rings are circular rings made of a spherical or two hemispherical piezoelectric material as a base material and cut with the center of the sphere as the cutting circle center. The piezoelectric composite rings are divided into a plurality of piezoelectric array elements along the circumferential direction. The piezoelectric composite rings are assembled into a spherical piezoelectric element with a spherical backing as a base. A polymer or vibration isolation and decoupling material pad is provided between two adjacent piezoelectric composite rings, and the gap between two adjacent piezoelectric array elements is filled with a polymer. The height and radial thickness of the piezoelectric array element are the same.

2. The high-frequency spherical piezoelectric element according to claim 1, wherein: A hole with a diameter of not less than 10 mm is opened on the top of the piezoelectric material sphere.

3. The high-frequency spherical piezoelectric element according to claim 1, wherein The inner and outer surfaces of the piezoelectric composite ring are respectively plated with a positive electrode and a negative electrode, and the positive electrode and the negative electrode of each piezoelectric composite ring are respectively welded together in parallel.

4. The high-frequency spherical piezoelectric element according to claim 1, wherein The polymer is epoxy resin, silicone rubber, polyurethane or phenolic resin.

5. A method for preparing a high-frequency spherical piezoelectric element according to any one of claims 1 to 4, characterized in that: The following steps are involved: Cutting step: using a spherical or two hemispherical piezoelectric materials as a base material, cutting it into a plurality of piezoelectric composite rings with equal surface widths with the center of the sphere as the cutting circle center, and then cutting a plurality of slits on the piezoelectric composite ring at equal intervals along the circumference of the piezoelectric composite ring to divide the piezoelectric composite ring into a plurality of piezoelectric array elements; One-time filling step: using a mold to fill the gaps between adjacent piezoelectric elements with polymer; Polishing step: After the polymer is cured, the electrode surfaces on the inner and outer surfaces of the piezoelectric composite ring are polished off so that the height of the piezoelectric array element is the same as the radial thickness; Electrode plating step: plating electrodes on the inner and outer surfaces of the piezoelectric composite ring, which serve as the positive electrode and negative electrode of the piezoelectric composite ring respectively; Molding steps: placing the piezoelectric composite rings into the set mold in sequence, using the spherical backing as the base, filling the space between two adjacent piezoelectric composite rings with polymer, and assembling the piezoelectric composite rings into a spherical piezoelectric element; or placing the piezoelectric composite rings and the vibration isolation and decoupling material pads into the set mold at intervals, using the spherical backing as the base, bonding the vibration isolation and decoupling material pads and the piezoelectric composite rings together, and thus assembling the spherical piezoelectric element; Welding steps: After forming, the positive and negative electrodes of each piezoelectric composite ring are welded together in parallel.

6. The method according to claim 5, wherein In the cutting step, the width of the cutting gap is no greater than 1 mm.

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