Manufacturing method of integrated piezoelectric ceramic sheet capable of multi-segment focusing and focused ultrasonic transducer

Abstract

The present invention relates to a method for manufacturing a one-piece piezoelectric ceramic sheet capable of multi-segment focusing and a focused ultrasonic transducer. When manufacturing electrodes for a cylindrical arc-shaped ceramic sheet, one surface of the sheet is coated with an electrode material layer, while the other, opposite surface is coated with an upper electrode material layer spaced axially apart. The ends of each strip of electrode material layer spaced apart on the other opposite surface extend along the circumference of the sheet, resulting in the area not coated with electrode material forming a plurality of cylindrical arc-shaped strips spaced apart and arranged in a regular axial sequence. During polarization, the corresponding electrode material layers on the concave and convex surfaces of the ceramic sheet generate a piezoelectric effect. The areas on the concave surface not coated with the electrode material layer are not polarized and do not exhibit a piezoelectric effect. When such a piezoelectric ceramic sheet is fabricated into a focused ultrasonic transducer, the focusing occurs as line segments spaced apart on the same straight line on axis L. The size can be customized to suit individual requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of piezoelectric ceramic ultrasonic transducers, and in particular to a method for manufacturing an integrated piezoelectric ceramic sheet capable of multi-segment focusing and a focused ultrasonic transducer thereof. Background Art

[0002] Focused ultrasound transducers are widely used in the medical cosmetic industry for skin rejuvenation. Ultrasound waves have the characteristics of strong penetration, good directionality, and concentrated energy. These properties enable them to penetrate deep into the skin without damaging the surface, accurately reaching the desired area, and precisely focusing the ultrasonic energy within the target tissue, thereby changing the tissue. In cosmetic skin treatments, an ultrasonic transducer that can focus ultrasonic energy into discrete segments, similar to the dashed lines in engineering drawings, is sometimes required. To achieve this energy focusing characteristic, a commonly used method is to assemble several separate cylindrical arc-shaped piezoelectric ceramic sheets at a certain distance and coaxially to produce the desired ultrasonic transducer. The piezoelectric ceramic sheets in this ultrasonic transducer are cylindrical arc-shaped sheets, similar to the shape of a piece of sidewall material cut axially from the sidewall of a cylindrical tube. When operating, the piezoelectric ceramic sheets with this shape focus their energy on the central axis L of the cylinder where the ceramic sheet is located.

[0003] By arranging and combining multiple cylindrical arc-shaped piezoelectric ceramic sheets with narrow axial dimensions in parallel at intervals, although energy can be focused into discrete multi-segment shapes, the production process is cumbersome. First, individual deviations are prone to occur in the production process of a single ceramic sheet, and the consistency after combination is poor. Secondly, the fixation of multiple parallel piezoelectric ceramic sheets is a problem. The back of each piezoelectric ceramic sheet corresponds to a mounting support structure, and the overall positioning and precision require a high process to achieve. Such a structure limits the overall size, and a size that is too small cannot be achieved. Moreover, each piezoelectric ceramic sheet needs to be connected to a driving power supply, making the overall structure complex. Multiple piezoelectric ceramic sheets need to be processed individually, and the cumulative difference in precision errors is large, resulting in differences in the frequencies of the focused short line segments L1. A slight deviation will affect the overall energy output, making the energy focusing effect of the dotted line shape formed by the entire ultrasonic transducer poor, and the energy of the formed dotted line shape is unstable and has poor consistency. The most important thing is that for beauty devices made of focused ultrasonic transducers in the medical beauty industry, in order to adapt to different parts of the human body and ensure flexibility of use, they must be small and easy to hold to adapt to the changing contours of the face. The above-mentioned structure is not only difficult to achieve a smaller size, but also has poor consistency in energy focusing, and cannot form dense, discrete multi-segment shapes with short overall and individual lengths. It does not meet the limitations of the internal space of the beauty device and the requirements of energy wave accuracy. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for manufacturing an integrated piezoelectric ceramic sheet capable of multi-segment focusing and a focused ultrasonic transducer thereof, so as to solve the problem that due to the small internal space of the beauty instrument and the high precision requirements of the energy wave, a piezoelectric ceramic sheet and a focused transducer with a small overall size, dense discrete multi-segment energy shape formed by focusing, stable energy and good consistency are needed.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A method for manufacturing an integrated piezoelectric ceramic sheet capable of multi-segment focusing,

[0007] Step 1: preparing raw materials for piezoelectric ceramic sheets into green materials;

[0008] Step 2: Blank forming

[0009] forming a green body from the green material;

[0010] Step 3: Sintering

[0011] Sintering the green body to form a dense ceramic green body;

[0012] Step 4: Cut and grind the ceramic body into cylindrical arc-shaped ceramic sheets, wherein the arc length of the ceramic sheet in the circumferential direction is less than half of the circumference, and the length of the ceramic sheet in the axial direction is not less than the total length of the required ultrasonic energy focused along the axis;

[0013] Step 5: Electrode Fabrication

[0014] The cylindrical arc-shaped ceramic sheet has two opposite surfaces, a concave surface and a convex surface. The side facing the central axis L is the concave surface, and the back of the concave surface is the convex surface. One of the two opposite surfaces of the ceramic sheet is covered with an electrode material layer, and the other opposite surface of the ceramic sheet is sequentially separated from each other in the axial direction into a plurality of electrode material layer-covered areas and non-electrode material-covered areas. Then, each electrode material layer-covered area set axially apart on the other opposite surface of the ceramic sheet is covered with an upper electrode material layer, and the areas between the separated and adjacent electrode material layers on the other opposite surface of the ceramic sheet are non-electrode material-covered areas. The electrode material layers and the non-electrode material areas on the other opposite surface of the ceramic sheet are sequentially spaced in the axial direction into strip shapes and arranged neatly. The separated electrode material layers on the other opposite surface of the ceramic sheet extend in the circumferential directions of the ceramic sheet, and the arc length of each separated electrode material layer extending in the circumferential direction is greater than the width along the axial direction.

[0015] Step 6: Polarization

[0016] Voltage is applied to the electrode material layer on the concave surface and the electrode material layer on the convex surface of the ceramic piece, so that the electrode material layer areas corresponding to the concave and convex surfaces of the ceramic piece are polarized along the thickness direction, forming a piezoelectric ceramic piece with piezoelectric effect.

[0017] As a preferred embodiment, in step 4, the thickness accuracy of the ground ceramic sheet is ±5 microns, the thickness uniformity of the ceramic sheet is ±5 microns, and the cylindricity tolerance of the ceramic sheet is ±5 microns.

[0018] As a preferred embodiment, in step 5, one side of the ceramic sheet is first covered with an electrode material layer and then dried, and then the other opposite side of the ceramic sheet is covered with an electrode material layer and then dried.

[0019] As a preferred embodiment, in step 5, the axial width of each spaced strip electrode material layer is the length of the energy of a single short line segment L1 focused on the axis L by the piezoelectric ceramic piece, and the axial width of each strip area not covered with electrode material is the spacing distance between adjacent focused short line segments L1.

[0020] As a preferred embodiment, in step 5, the convex surface of the ceramic sheet is covered with an electrode material layer, and the concave surface of the ceramic sheet is separated into a plurality of areas covered with the electrode material layer and areas not covered with the electrode material layer in sequence along the axial direction.

[0021] As a preferred embodiment, in step 5, the concave surface of the ceramic piece is covered with an edge electrode material layer along the axial direction near the edges of both sides of the circumference, and the edge electrode material layer connects all the electrode material layers arranged at intervals on the concave surface of the ceramic piece.

[0022] As a preferred embodiment, in step 5, in order to ensure that the electrode material layers arranged at intervals on the concave surface of the ceramic sheet are evenly spaced and covered, a template ruler is used to standardize the position of the concave surface of the ceramic sheet before covering the electrode material layers.

[0023] As a preferred embodiment, the template ruler is provided with strip-shaped holes corresponding one-to-one to the spaced-apart areas not covered with electrode material. The template ruler is laminated on the concave surface of the ceramic sheet, and then the membrane is attached to the concave surface of the ceramic sheet through the holes of the template ruler in turn. Then, the template ruler is removed, and the concave surface of the ceramic sheet with the membrane is covered with the electrode material layer, and then the electrode material layer on the concave surface of the ceramic sheet is dried. After drying, the membrane on the concave surface of the ceramic sheet is removed.

[0024] As a preferred embodiment, the template ruler is provided with baffles corresponding to the areas not covered with electrode material, and the same end of all baffles is connected by an axial connecting edge. The template ruler is hollowed out except for the baffles and the connecting plate. The connecting edge of the template ruler is flush with one side of the ceramic piece parallel to the axial direction, and the two ends of the connecting edge in the axial direction are flush with the two ends of the ceramic piece in the axial direction. The template ruler is laminated and placed on the concave surface of the ceramic piece, and the unobstructed part of the baffle on the ceramic piece is covered with the electrode material layer, and then the electrode material layer on the concave surface of the ceramic piece is dried. After drying, the electrode material layer is attached to the corresponding part of the connecting edge on the concave surface of the ceramic piece, and then dried again.

[0025] A focused ultrasonic transducer comprises a piezoelectric ceramic sheet formed by any of the methods for manufacturing an integrated piezoelectric ceramic sheet capable of multi-segment focusing.

[0026] The beneficial effects of the present invention are: in order to achieve the requirements of small overall size, dense focusing of multiple separated segments, and high energy focusing accuracy, when making ceramic sheets, the shape of the ceramic sheets is cut and ground into a whole cylindrical arc-shaped sheet. The high-precision grinding performed at the same time effectively ensures the thickness frequency consistency of the piezoelectric ceramic sheet, and the size of the ceramic sheet can be similar to the size of a coin or even smaller. In the process of making the electrode, the electrode material layer is not coated in the specific positions of the separated strips on the concave surface of the ceramic sheet, and the electrode material layer is coated on the entire convex surface. For example, the axial width of the spaced electrode material layer can be 2 mm or even smaller, and the length of the short line segment L1 formed by the corresponding focusing is the axial width of the electrode material layer, that is, 2 mm or less. The ceramic sheet and the electrode material High precision in the size of the material layer is easy to achieve, so that the formed focused discrete short line segments L1 are dense. During the polarization process, the electric dipoles of the grains inside the electrode material layers corresponding to the concave and convex surfaces of the ceramic piece are arranged and polarized along the thickness direction, and a piezoelectric effect is generated at the corresponding electrode material layers on the concave and convex surfaces of the ceramic piece. The positions on the concave surface of the ceramic piece that are not coated with the electrode material layer and the corresponding convex surface are not polarized, so that the positions on the concave surface of the ceramic piece that are not coated with the electrode material layer and the corresponding convex surface do not have a piezoelectric effect along the thickness direction. After such a piezoelectric ceramic piece is made into a focused ultrasonic transducer, the focusing appears on the axis L as short line segments L1 arranged at intervals on the same straight line, that is, in the shape of a dotted line, and a short line segment L1 of very small length can be achieved. In this way, the multi-segment energy that is focused separately not only has high dimensional precision, but also has a stable focusing effect. The piezoelectric ceramic piece can achieve overall vibration when connected to a driving power supply. The ultrasonic transducer made of the above-mentioned integral piezoelectric ceramic piece has a simple overall structure and is easy to install. The size can be made according to requirements, and can be large or small. It can be made into a very small size and has strong adaptability. The energy focusing effect of the dotted line shape formed is stable and the energy focusing consistency is good. It is suitable for application in the field of medical beauty. The coin-sized beauty instrument probe fits the face, such as around the corner of the eye, and is very suitable for it. It penetrates into the skin to form a dense discrete short line segment L1 energy focus, which changes the internal structure of the skin. The energy focusing size is small and the precision is high, and the energy is stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings, wherein:

[0028] Figure 1 Schematic diagram of the structure of the piezoelectric ceramic sheet of the present invention;

[0029] Figure 2 This is a schematic diagram of a first embodiment of the present invention wherein a ceramic sheet is covered with an electrode material layer with assistance of a template ruler;

[0030] Figure 3 A schematic diagram of a second embodiment of the present invention of using a template ruler to assist in coating a ceramic sheet with an electrode material layer;

[0031] Figure 4 This is a physical picture of the piezoelectric ceramic sheet of the present invention;

[0032] Figure 1-Figure 4 Explanation of the reference numerals in the accompanying drawings: 1. piezoelectric ceramic sheet; 2. template ruler; 3. diaphragm; 4. ceramic sheet; 11. area not covered with electrode material; 12. electrode material layer; 21. hole; 22. baffle; 23. connecting edge. DETAILED DESCRIPTION

[0033] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] See also Figure 1-Figure 4 FIG. 1 shows a method for manufacturing an integrated piezoelectric ceramic sheet capable of multi-segment focusing according to the present invention, specifically comprising:

[0035] Step 1: preparing a raw material for the piezoelectric ceramic sheet 1 into a blank-making material;

[0036] Step 2: Blank forming

[0037] The blanking material is formed into a blank; the formed blank needs to be dried to remove excess moisture to avoid cracks during the subsequent sintering process.

[0038] Step 3: Sintering

[0039] The green body is sintered. At high temperature, the particles in the green body are sintered to form a dense ceramic sheet green body;

[0040] Step 4: Cut and grind the ceramic body into a cylindrical arc-shaped ceramic sheet 4, with the arc length of the ceramic sheet 4 in the circumferential direction being less than half of the circumference, so that the axis is outside the ceramic sheet 4. When applied, the energy is focused on the axis outside to achieve penetration into the human skin. The axial length of the ceramic sheet 4 is not less than the total length of the required ultrasonic energy focused along the axis;

[0041] According to the needs of energy focusing, the size of the ceramic sheet 4 is determined. The size of the ceramic sheet 4 is now determined as follows: the axial length is 20 mm, the width is 10 mm, the thickness of the ceramic sheet 4 is 3 mm, the circumferential radius of the ceramic sheet 4 is 25 mm, the arc surface of the ceramic sheet 4 along the circumferential direction is one-sixth of the circumference, the thickness accuracy of the ground ceramic sheet 4 is ±5 microns, the thickness uniformity of the ceramic sheet 4 is ±5 microns, and the cylindrical tolerance of the ceramic sheet 4 is ±5 microns. It is necessary to ensure the overall processing accuracy of the ceramic sheet 4 in order to achieve high overall dimensional accuracy of the sheet-shaped ceramic sheet 4, because the ultrasonic energy frequency of the piezoelectric ceramic sheet 1 is related to the thickness, and the energy focusing position is related to the position of the circumference. High accuracy can ensure the consistency of the ultrasonic energy frequency and position of the piezoelectric ceramic sheet 1.

[0042] Step 5: Electrode Fabrication

[0043] The cylindrical arc-shaped ceramic sheet 4 has two opposite surfaces, a concave surface and a convex surface. The side facing the central axis L is the concave surface, and the back of the concave surface is the convex surface. One of the two opposite surfaces of the ceramic sheet 4 is covered with an electrode material layer 12, and the other opposite surface of the ceramic sheet 4 is divided into multiple areas covered with the electrode material layer 12 and areas not covered with the electrode material 11 in sequence along the axial direction. The two opposite surfaces need to be made of upper electrodes to exert their piezoelectric effect. The electrode material is silver paste, and the electrode is made by evenly applying it with a brush.

[0044] In this embodiment, the concave surface of the ceramic sheet 4 is separated into a plurality of electrode material layer covered areas and uncovered electrode material areas 11 in sequence along the axial direction, and each electrode material layer covered area separated in the axial direction of the concave surface of the ceramic sheet 4 is covered with an upper electrode material layer 12, and the axial width of each electrode material layer 12 separated on the concave surface is set to 2 mm. The area between the adjacent electrode material layers 12 separated on the concave surface of the ceramic sheet 4 is uncovered electrode material area 11, and the axial width of each uncovered electrode material area 11 is 3 mm. The electrodes 12 are arranged in a strip-like shape in a axial direction in sequence, with four groups of them arranged in a strip-like shape. The separated electrode material layers 12 on the concave surface of the ceramic sheet 4 extend along both sides of the circumference of the ceramic sheet 4. The arc length of each separated electrode material layer 12 extending in the circumferential direction is greater than the width in the axial direction. The axial width of each strip-like electrode material layer 12 is the energy length of a single short line segment L1 corresponding to the piezoelectric ceramic sheet 1 focused on the axis L, that is, the length of L1 is 2 mm. The axial width of each area not covered with electrode material 11 is the spacing distance between adjacent focused short line segments L1, which is 3 mm.

[0045] In step 5, in order to ensure that the electrode material layers 12 arranged at intervals on the concave surface of the ceramic sheet 4 are evenly spaced and accurately sized, the electrode material layers 12 on the concave surface of the ceramic sheet 4 are first positioned on the concave surface of the ceramic sheet 4 using a template ruler 12 before the electrode material layers 12 are applied. For ease of operation, various types of template rulers 12 are available, and two embodiments are provided below.

[0046] like Figure 2This is the first embodiment of the template ruler 2. A template is made that is consistent with the shape and size of the concave surface of the ceramic sheet 4. Then, strip-shaped holes 21 corresponding to the spaced-apart areas 11 not covered with electrode materials are opened on the template to form the template ruler 2. The template ruler 2 is aligned with the ceramic sheet 4 and placed on the concave surface of the ceramic sheet 4. The diaphragm 3 is then attached to the concave surface of the ceramic sheet 4 through the holes 21 of the template ruler 2. The diaphragm 3 is positioned and attached to the concave surface of the ceramic sheet 4 through the template ruler 2. Then, the template ruler 4 is removed and the silver paste is dipped with a brush to form the ceramic sheet. 4. The electrode material layer 12 is applied to the concave surface of the ceramic sheet 4. The electrode material layer 12 is applied between adjacent diaphragms 3 on the concave surface. The edge electrode material layer is applied axially near the edges of the circumference on both sides of the concave surface of the ceramic sheet 4. The edge electrode material layer connects all the electrode material layers 12 arranged at intervals on the concave surface of the ceramic sheet 4, which facilitates the connection of the voltage position during polarization and the connection of the electrode leads of the manufactured piezoelectric ceramic sheet 1. The electrode material layer 12 on the concave surface of the ceramic sheet 4 is then dried. After drying, the diaphragms 3 on the concave surface of the ceramic sheet 4 are removed.

[0047] like Figure 3 This is the second embodiment of the template ruler 2. A template that is consistent with the shape and size of the concave surface of the ceramic sheet 4 is made, and then baffles 22 corresponding to the areas 11 not covered with electrode material are provided on the template. The same end of all baffles 22 is connected by an axial connecting edge 23. The template is hollowed out except for the baffles 22 and the connecting plate 23 to form a template ruler 2, and the connecting edge 23 of the template ruler 2 is flush with one side edge of the ceramic sheet 4 parallel to the axial direction, and the two ends of the connecting edge 23 along the axial direction are flush with the two ends of the ceramic sheet 4 along the axial direction. The template ruler 2 is aligned with the ceramic sheet 4 and laminated on the concave surface of the ceramic sheet 4. The electrode material layer 12 is applied to the portion of the ceramic sheet 4 that is not blocked by the baffle 22, and the electrode material layer 12 on the concave surface of the ceramic sheet 4 is dried. After drying, the electrode material layer 12 is applied to the portion corresponding to the connecting edge 23 on the concave surface of the ceramic sheet 4, and then dried again.

[0048] The above two operation methods are both for the precise coating position of the electrode material layer 12 on the concave surface of the ceramic sheet 4, so that the area 11 not coated with the electrode material is shaped into a plurality of strips arranged in sequence along the axial direction, and the electrode material layer 12 is coated on the concave surface of the ceramic sheet 4;

[0049] Then, the electrode material layer 12 is applied to the convex surface of the ceramic sheet 4. The application position of the electrode material layer 12 on the convex surface should correspond to the electrode material layer 12 arranged at intervals on the concave surface. For the convenience of application, the electrode material layer 12 can be applied to the entire convex surface. This can more conveniently and quickly complete the production process of the ceramic sheet 4 electrode. After the electrode material layer 12 on the convex surface of the ceramic sheet 4 is applied, it is necessary to dry it.

[0050] After the electrodes on the concave and convex surfaces of the ceramic sheet 4 are coated and dried, the ceramic sheet 4 covered with the completed electrode material layer 12 is subjected to silver firing treatment so that the electrode material layers 12 on the concave and convex surfaces of the ceramic sheet 4 are firmly attached to the ceramic sheet 4 and can conduct electricity evenly.

[0051] Step 6: Polarization

[0052] Polarization is one of the key steps to give the ceramic sheet 4 a piezoelectric effect. The ceramic sheet 4 is placed in high-temperature oil, and a high-voltage electric field is applied to the electrode material layers 12 on both the concave and convex surfaces of the ceramic sheet 4. A voltage difference is generated along the thickness direction between the electrode material layers 12 spaced apart on the concave surface of the ceramic sheet 4 and the electrode material layers 12 corresponding to the convex surface. Under the action of the high-voltage electric field of the electrode material layers 12 corresponding to the concave and convex surfaces, the electric dipoles of the internal grains of the ceramic sheet 4 are arranged and polarized along the thickness direction, forming a piezoelectric ceramic sheet 1 with a piezoelectric effect. When the electrode material layers 12 on the two opposite surfaces of the piezoelectric ceramic sheet 1 are driven by an electric signal, the interior of the piezoelectric ceramic sheet 1 vibrates at the electrode material layers 12 on both opposite surfaces, which can form an ultrasonic energy focus along the axis L of the cylindrical surface where the piezoelectric ceramic sheet 1 is located.

[0053] In the area of ​​the ceramic sheet 4 where the electrode material layer 12 is not applied and is spaced apart from each other on the concave surface, there is no conductive electrode material layer 12. At this location, no voltage can be generated between the concave and convex surfaces along the thickness direction. Therefore, this part of the ceramic sheet 4 is not polarized and does not have a piezoelectric effect. Therefore, when driven by an electrical signal, no ultrasonic energy focusing can be achieved.

[0054] The integrated piezoelectric ceramic sheet 1 produced by the method of the present invention has a ceramic sheet 4 to which each electrode material layer 12 is attached, which is an integrated ceramic sheet 4 produced in one step. This effectively ensures dimensional accuracy and overall consistency, and also allows the electrode material layers 12 spaced apart on the concave surface and the electrode material layer 12 fully coated on the convex surface of the integrated ceramic sheet to be evenly coated. When the ceramic sheet 4 is polarized, the polarization effect of each part is uniform, and the energy focusing generated by the formed piezoelectric ceramic sheet 1 is consistent. This structural arrangement only requires a single polarization process to complete the polarization process, which not only reduces the workload of polarization, but also minimizes individual differences in polarization, thereby ensuring the consistency of the overall output power of the piezoelectric ceramic sheet 1.

[0055] When the piezoelectric ceramic sheet 1 is used, the electrode material layers 12 on the concave and convex surfaces are connected to electrodes. Under the action of an electrical signal, the piezoelectric ceramic sheet 1 can be focused on the axis LL of the cylindrical surface on which the piezoelectric ceramic sheet 1 is located. The shape is discontinuous and separated short line segments L1.

[0056] The piezoelectric ceramic sheet 1 manufactured by this method is used in a focused ultrasonic transducer as follows:

[0057] like Figure 4 As shown, the piezoelectric ceramic sheet 1 prepared by the method steps of the present invention is used as the core functional element of a focused ultrasonic transducer in actual use. Electrode leads are welded to the electrode material layers 12 on both the concave and convex surfaces of the piezoelectric ceramic sheet 1, respectively. The electrode leads on opposite sides are connected to a driving power supply. The electrode material layer 12 on the concave surface of the piezoelectric ceramic sheet 1 is connected to the negative electrode, and the electrode material layer 12 on the convex surface of the piezoelectric ceramic sheet 1 is connected to the positive electrode. The piezoelectric ceramic sheet 1 is enclosed in a housing with the concave surface facing outward, forming a discrete multi-segment focused ultrasonic transducer capable of focusing on the axis L. The transducer forms an energy focus with short segments L1 each having a length of 2 mm. The short segments L1 are spaced 3 mm apart, and there are four separated short segments L1. The total energy focus linear length is 20 mm. The overall size is similar to that of a coin. The transducer is used in the medical beauty industry and is injected into the skin to form discontinuous short segment L1 energy focus. The energy focus is stable and highly precise, and has a wide range of application scenarios. Moreover, only one driving power supply is needed to realize driving with stable power and frequency. By changing the manufacturing method of the piezoelectric ceramic sheet 1 and optimizing the structure, the product is simple and easy to install and use.

[0058] The above embodiments are merely illustrative of the principles and effects of the present invention, as well as some embodiments of its application, and are not intended to limit the present invention. It should be noted that a person skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for manufacturing an integrated piezoelectric ceramic sheet capable of multi-segment focusing, characterized in that: Step 1: preparing raw materials for piezoelectric ceramic sheets into green materials; Step 2: Blank Forming forming a green body from the green material; Step 3: Sintering Sintering the green body to form a dense ceramic green body; Step 4: Cut and grind the ceramic body into cylindrical arc-shaped ceramic sheets, wherein the arc length of the ceramic sheet in the circumferential direction is less than half of the circumference, and the length of the ceramic sheet in the axial direction is not less than the total length of the required ultrasonic energy focused along the axis; Step 5: Electrode Fabrication The cylindrical arc-shaped ceramic sheet has two opposite surfaces, a concave surface and a convex surface. The side facing the central axis L is the concave surface, and the back of the concave surface is the convex surface. One of the two opposite surfaces of the ceramic sheet is covered with an electrode material layer, and the other opposite surface of the ceramic sheet is sequentially separated from each other along the axial direction into a plurality of electrode material layer-covered areas and non-electrode material-covered areas. Then, each electrode material layer-covered area set axially apart on the other opposite surface of the ceramic sheet is covered with an upper electrode material layer, and the area between the separated and adjacent electrode material layers on the other opposite surface of the ceramic sheet is the non-electrode material area. The electrode material layers and uncovered electrode material areas on the other opposite surface of the ceramic sheet are sequentially spaced and neatly arranged in strip shapes along the axial direction. The separated electrode material layers on the other opposite surface of the ceramic sheet extend along both sides of the circumference of the ceramic sheet, and the arc length of each separated electrode material layer extending in the circumferential direction is greater than the width along the axial direction. The axial width of each separated strip electrode material layer is the length of the energy of a single short line segment L1 corresponding to the energy focused on the axis L by the piezoelectric ceramic sheet, and the axial width of each strip uncovered electrode material area is the spacing distance between adjacent focused short line segments L1. Step 6: Polarization Voltage is applied to the electrode material layer on the concave surface and the electrode material layer on the convex surface of the ceramic piece, so that the electrode material layer areas corresponding to the concave and convex surfaces of the ceramic piece are polarized along the thickness direction, forming a piezoelectric ceramic piece with piezoelectric effect.

2. The method for manufacturing an integrated piezoelectric ceramic sheet capable of multi-segment focusing according to claim 1, characterized in that: In step 4, the thickness accuracy of the ground ceramic sheet is ±5 microns, the thickness uniformity of the ceramic sheet is ±5 microns, and the cylindricity tolerance of the ceramic sheet is ±5 microns.

3. The method for manufacturing an integrated piezoelectric ceramic sheet capable of multi-segment focusing according to claim 1, characterized in that: In step 5, one side of the ceramic sheet is first covered with an electrode material layer and then dried, and then the other opposite side of the ceramic sheet is covered with an electrode material layer and then dried.

4. The method for manufacturing an integrated piezoelectric ceramic sheet capable of multi-segment focusing according to claim 1, 2 or 3, characterized in that: In step 5, the convex surface of the ceramic sheet is covered with an electrode material layer, and the concave surface of the ceramic sheet is divided into a plurality of areas covered with the electrode material layer and areas not covered with the electrode material, spaced apart from each other in the axial direction.

5. The method for manufacturing an integrated piezoelectric ceramic sheet capable of multi-segment focusing according to claim 4, characterized in that: In step 5, the concave surface of the ceramic piece is covered with an edge electrode material layer along the axial direction near the edges of both sides of the circumference, and the edge electrode material layer connects all the electrode material layers arranged at intervals on the concave surface of the ceramic piece.

6. The method for manufacturing an integrated piezoelectric ceramic sheet capable of multi-segment focusing according to claim 5, characterized in that: In step 5, in order to ensure that the electrode material layers arranged at intervals on the concave surface of the ceramic sheet are evenly spaced and covered, a template ruler is used to standardize the position of the concave surface of the ceramic sheet before covering the electrode material layers.

7. The method for manufacturing an integrated piezoelectric ceramic sheet capable of multi-segment focusing according to claim 6, characterized in that: The template ruler is provided with strip-shaped holes corresponding to the spaced-apart areas not covered with electrode material. The template ruler is laminated on the concave surface of the ceramic sheet, and then the membrane is attached to the concave surface of the ceramic sheet through the holes of the template ruler in turn. Then the template ruler is removed, and the concave surface of the ceramic sheet with the membrane is covered with the electrode material layer, and then the electrode material layer on the concave surface of the ceramic sheet is dried. After drying, the membrane on the concave surface of the ceramic sheet is removed.

8. The method for manufacturing an integrated piezoelectric ceramic sheet capable of multi-segment focusing according to claim 6, characterized in that: The template ruler is provided with baffles corresponding to the areas not covered with electrode material, and the same end of all baffles is connected by an axial connecting edge. The template ruler is hollowed out except for the baffles and the connecting plate. The connecting edge of the template ruler is flush with one side of the ceramic piece parallel to the axial direction, and the two ends of the connecting edge in the axial direction are flush with the two ends of the ceramic piece in the axial direction. The template ruler is laminated on the concave surface of the ceramic piece, and the unblocked part of the baffle on the ceramic piece is covered with the upper electrode material layer, and then the electrode material layer on the concave surface of the ceramic piece is dried. After drying, the corresponding part of the connecting edge on the concave surface of the ceramic piece is covered with the upper electrode material layer again, and then dried again.

9. A focused ultrasonic transducer, characterized in that: The focused ultrasonic transducer comprises a piezoelectric ceramic sheet formed by the method for manufacturing an integrated piezoelectric ceramic sheet capable of multi-segment focusing according to any one of claims 1 to 8.

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