High-precision matching layer and encapsulation layer thickness control for ultrasonic transducer encapsulation device

Abstract

This invention relates to an ultrasonic transducer encapsulation device for high-precision control of the matching layer and encapsulation layer thickness, belonging to the field of ultrasonic transducer manufacturing and encapsulation. The invention includes an encapsulation mold body, a bottom lifting plate, a micrometer probe adjustment mechanism, an encapsulation slot, a pressure balance hole, and a height adjustment structure. The encapsulation mold body is used to adapt to ultrasonic transducer arrays of different specifications. The encapsulation slot is used to accommodate the ultrasonic transducer and encapsulation material, including single-encapsulation and double-encapsulation modes. The bottom lifting plate can adjust the thickness of the matching layer and encapsulation layer. The micrometer probe adjustment mechanism includes a standard micrometer probe and an adjustment knob, used to achieve micrometer-level thickness adjustment of the matching layer and encapsulation layer. The pressure balance hole is used to reduce bubble formation. The height adjustment structure is used to fix the transducer structure and improve encapsulation consistency. This invention can control the thickness of the matching layer and encapsulation layer within a micrometer-level precision range, and also has the advantages of high precision, adjustability, and compatibility with transducers of various sizes.

Description

Technical Field

[0001] This invention belongs to the field of ultrasonic transducer manufacturing and packaging technology, specifically involving an ultrasonic transducer packaging device with high-precision matching layer and packaging layer thickness control, which is suitable for applications such as medical ultrasonic imaging, underwater detection, and industrial flaw detection. Background Technology

[0002] Ultrasonic transducers are widely used in medical imaging, non-destructive testing, underwater exploration, and other fields. Their performance is affected by the design and manufacturing quality of the matching layer and encapsulation layer. The matching layer optimizes acoustic impedance matching and improves sound wave transmission efficiency; the encapsulation layer, in addition to providing mechanical protection and environmental sealing, also affects the acoustic impedance matching of the transducer, therefore its thickness also needs to be precisely controlled. However, existing technologies have shortcomings in the manufacturing precision, encapsulation consistency, and production efficiency of the matching layer and encapsulation layer, making it difficult to meet the requirements of high-performance transducers. Where c s Let f0 be the sound velocity of the matching layer material, and f0 be the operating center frequency of the transducer. For example, the theoretical thickness of the matching layer for a 5MHz transducer is approximately 0.075mm (assuming a sound velocity c0). s =1500m / s). However, traditional manual encapsulation or fixed mold methods cannot ensure this precision, with errors often exceeding ±0.05mm, leading to poor impedance matching, narrower transducer bandwidth, and increased signal loss. The encapsulation layer also affects acoustic performance, typically needing to meet the λ / 4 transmission principle. For example, the encapsulation layer thickness for a 5MHz transducer should be controlled between 0.2mm and 2mm to optimize sound wave transmission. However, existing encapsulation methods mostly employ manual pouring or monolithic casting, resulting in imprecise thickness control and an inability to simultaneously ensure encapsulation integrity and impedance matching optimization.

[0003] Currently, the matching layer and encapsulation layer of transducers are mainly produced by manual coating, integral casting, and limiting molds, but all of these methods have shortcomings: (1) Manual coating is suitable for small transducers, but the thickness uniformity is poor, which affects the acoustic impedance matching. (2) Integral casting makes it difficult to accurately control the thickness of the encapsulation layer, resulting in inconsistent performance of the transducer between different batches. (3) Although limiting molds can provide a certain degree of thickness control, the accuracy is usually only at the millimeter level, which is difficult to meet the requirements of micron-level thickness control for high-frequency transducers (above 5MHz), resulting in a decrease in the signal transmission efficiency of the transducer. In addition, micro bubbles are easily formed during the encapsulation process, affecting the uniformity of the encapsulation layer and further reducing the acoustic performance of the transducer. The electrode solder joints of the transducer are usually located on the side and connected to the external drive circuit through cables. However, in underwater acoustic or humid environments, if the solder joints are not completely encapsulated, short circuits, water seepage, or corrosion are likely to occur, leading to a decrease in the transducer's performance. Traditional encapsulation methods make it difficult to ensure that the encapsulation material completely covers the solder joints while ensuring the stability of the transducer's signal transmission, which poses a reliability risk during long-term use.

[0004] The production of ultrasonic transducers involves transducer arrays of different specifications (such as 16×16, 20×20, 32×32, etc.), but existing packaging methods mostly use single-size fixed molds, which cannot be compatible with transducers of different sizes, resulting in low production efficiency and high costs. Manual packaging methods are complex and rely on manual operation, which not only affects consistency but also increases the defect rate, resulting in large deviations in the thickness of the matching layer and the packaging layer of the transducer, making it difficult to guarantee the consistency of product quality in mass production.

[0005] In summary, current transducer matching layer and encapsulation layer packaging technologies face the following challenges: insufficient precision in matching layer thickness control makes it difficult to meet the λ / 4 design requirements, leading to increased acoustic wave reflection and limited signal bandwidth. The lack of precise control over the encapsulation layer thickness prevents adequate optimization of acoustic impedance matching and affects packaging integrity and long-term stability. Existing manual packaging or fixed mold methods are inefficient, unsuitable for mass production of transducers of different sizes, resulting in high production costs and poor product consistency. Insufficient protection of transducer solder joints makes them prone to short circuits, corrosion, and signal attenuation in underwater acoustic or humid environments, impacting the long-term reliability of the equipment. Therefore, there is an urgent need for a high-precision, adjustable mold device compatible with multiple transducer sizes, capable of controlling the matching layer and encapsulation layer thickness within a micrometer-level precision range. This would improve the consistency and controllability of the packaging process and meet the needs of large-scale production and long-term use, thereby enhancing the overall performance and reliability of ultrasonic transducers. Summary of the Invention

[0006] To address the problems of insufficient precision in controlling the thickness of the matching layer and encapsulation layer, poor product consistency, and high difficulty in mass production in existing ultrasonic transducer packaging processes, this invention proposes an ultrasonic transducer packaging device with high-precision matching layer and encapsulation layer thickness control. This device can control the thickness of the matching layer and encapsulation layer within a micrometer-level precision range, improving the consistency and controllability of the packaging process and meeting the requirements of large-scale production and long-term use, thereby enhancing the overall performance and reliability of the ultrasonic transducer. This invention also offers advantages such as high precision, adjustability, and compatibility with transducers of various sizes.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] The ultrasonic transducer encapsulation device for high-precision matching layer and encapsulation layer thickness control disclosed in this invention includes an encapsulation mold body, a bottom lifting plate, a micrometer measuring rod adjustment mechanism, an encapsulation groove, an air pressure balance hole, and a height adjustment structure.

[0009] The main body of the encapsulation mold is made of high-strength aluminum alloy or stainless steel, with a thickness of 3-5mm, and is equipped with multiple encapsulation slots to adapt to ultrasonic transducer arrays of different specifications.

[0010] The encapsulation slot is used to accommodate the ultrasonic transducer and encapsulation material. The size of the encapsulation slot is adjustable and includes single-encapsulation and double-encapsulation modes, supporting step-by-step encapsulation of the matching layer and the encapsulation layer.

[0011] The bottom lifting plate can adjust the thickness of the matching layer and the encapsulation layer. There is a gap of 0.1 to 0.3 mm between its edge and the wall of the encapsulation groove to ensure adjustment accuracy and avoid shaking or error.

[0012] The micrometer probe adjustment mechanism is installed at the bottom of the packaging mold and includes a standard micrometer probe and an adjustment knob. The probe extension is controlled by a micrometer cylinder to achieve micrometer-level thickness adjustment between the matching layer and the packaging layer.

[0013] The pressure balancing hole is located at the bottom of the packaging groove and has a diameter of 5-8mm. It balances the internal and external pressures during the packaging process, reduces the formation of air bubbles, and improves the uniformity of packaging.

[0014] The height adjustment structure includes a detachable height adjustment rod and a positioning beam, which are connected by threads to fix the transducer structure, prevent the transducer from shifting or tilting during the packaging process, and improve packaging consistency.

[0015] Furthermore, the encapsulation slot has a two-level structure, including a small encapsulation slot for the mating layer and a large encapsulation slot for the outer encapsulation layer. The two slots differ in size by 2mm to accommodate the two-step encapsulation mode of the mating layer + outer encapsulation layer and achieve acoustic optimization.

[0016] Furthermore, the bottom lifting plate is controlled by a micrometer probe adjustment mechanism. The extension length of the probe can be adjusted by rotating the micrometer cylinder, allowing the lifting plate to rise and fall within a precision range of 0.01mm, thereby precisely controlling the thickness of the matching layer and the encapsulation layer.

[0017] Furthermore, the measurement accuracy of the micrometer probe is 0.01 mm, ensuring that the error of the matching layer and the encapsulation layer thickness is controlled within ±0.01 mm, thereby improving the acoustic impedance matching effect of the ultrasonic transducer and optimizing the ultrasonic transmission efficiency.

[0018] Furthermore, a circumferential allowance of 1.5 to 2.5 mm is reserved in the encapsulation groove to ensure that the transducer electrode solder joints are completely covered in the encapsulation material, preventing short circuits, water seepage, and signal attenuation in underwater or humid environments, and improving the long-term stability of the transducer.

[0019] Furthermore, the main body of the packaging mold is equipped with standardized adjustment holes, which can be adapted to micrometer probes of different specifications to meet the matching layer and packaging layer thickness requirements of transducers of different frequencies.

[0020] Furthermore, a sliding passage is provided between the height adjustment rod and the main body of the packaging mold, allowing the height adjustment rod to remain vertically limited during the packaging process, and to be inserted into the positioning socket through the positioning beam pin, forming a highly stable limiting system to prevent the transducer from shifting or tilting.

[0021] Furthermore, the bottom of the packaging tank is provided with a bottom adjustment hole with a diameter of 5-6 mm. The bottom adjustment hole is used to insert a standard micrometer measuring rod, and the height of the bottom lifting plate is adjusted by rotating the micrometer cylinder to achieve micrometer-level control of the packaging thickness.

[0022] Furthermore, it is compatible with ultrasonic transducer arrays of different specifications, including 16×16, 20×20, and 32×32.

[0023] The frequency range of transducers of different frequencies is 5MHz to 15MHz.

[0024] The height adjustment structure includes a detachable height adjustment rod and a positioning beam, which are connected by an M6 thread.

[0025] This invention discloses a high-precision packaging method for an ultrasonic transducer matching layer and an encapsulation layer, used for packaging ultrasonic transducers using the aforementioned packaging device, comprising the following steps:

[0026] S1, Matching layer encapsulation:

[0027] Step 1.1: Select the appropriate small encapsulation slot and adjust the micrometer probe to the target matching layer thickness.

[0028] Step 1.2: Inject matching layer material into the small encapsulation tank and vent air through the air pressure balance hole to reduce air bubbles.

[0029] Step 1.3: After the matching layer has cured, use a micrometer probe to lift the bottom lifting plate to demold the transducer and obtain the semi-finished product of "piezoelectric material + matching layer".

[0030] S2, Encapsulation layer encapsulation:

[0031] Step 2.1: Transfer the semi-finished product to the appropriate large packaging tank and adjust the micrometer probe to the target packaging layer thickness.

[0032] Step 2.2: Inject the encapsulation layer material into the encapsulation tank and balance the pressure through the air pressure balancing hole to avoid uneven encapsulation.

[0033] Step 2.3: Perform encapsulation and curing. After complete curing, use the micrometer probe to adjust the lifting plate again to demold the transducer and obtain a fully encapsulated transducer.

[0034] S3, Multi-specification transducer mass packaging:

[0035] Step 3.1: Select the appropriate encapsulation slot based on the transducer size.

[0036] Step 3.2: Use a micrometer probe to precisely control the thickness of the matching layer and the encapsulation layer to ensure that all transducer products have consistent encapsulation.

[0037] Step 3.3: Improve packaging efficiency by performing batch packaging operations.

[0038] Furthermore, the unidirectional dimension L of the encapsulation groove slot Calculated using the following formula:

[0039] L slot =L net +2c

[0040] L net = (m×a)+((m-1)×b

[0041] Where m is the number of array rows / columns (e.g., m = 16 for a 16×16 array), a is the width of the piezoelectric pillar (e.g., 1 mm), b is the pillar spacing (e.g., 0.5 mm), c is the side encapsulation thickness (1.5–2.5 mm), and L net The sensor element size of the transducer before encapsulation is given. L is calculated for a 16×16 array (a = 1 mm, b = 0.5 mm). net =23.5mm, take c=2mm, then L slot =27.5mm.

[0042] Furthermore, the wavelength λ is calculated as follows:

[0043]

[0044] According to the λ / 4 principle, the optimal matching layer thickness h match The calculation is as follows:

[0045]

[0046] Beneficial effects:

[0047] 1. The ultrasonic transducer packaging device for high-precision matching layer and encapsulation layer thickness control disclosed in this invention achieves micron-level thickness adjustment (error ≤ ±0.01mm) through the combination of micron measuring rod and bottom lifting plate. Compared with the traditional manual packaging method, it can accurately control the thickness of the matching layer and encapsulation layer, improve the acoustic impedance matching effect, and optimize the ultrasonic signal transmittance and the acoustic performance of the transducer.

[0048] 2. The ultrasonic transducer packaging device for high-precision matching layer and encapsulation layer thickness control disclosed in this invention adopts a modular packaging slot design, which is compatible with one-time packaging and two-time packaging processes. The main body of the packaging mold is provided with 6 packaging slots of different sizes (or three sets of small slots + large slots in pairs), which can be adapted to transducer arrays of different specifications, realize the packaging of multiple transducers in a single process, improve the efficiency of mass production, and reduce production costs.

[0049] 3. The ultrasonic transducer encapsulation device for high-precision matching layer and encapsulation layer thickness control disclosed in this invention employs a pressure balance hole (5-8mm) to effectively reduce air bubbles generated by residual gas during the encapsulation curing process, thereby improving the uniformity of the encapsulation layer and the stability of the ultrasonic signal. A micrometer-sized measuring rod adjusts the bottom lifting plate to achieve precise demolding, avoiding damage to the encapsulation layer or deformation of the transducer structure caused by traditional prying methods, thus improving the product qualification rate.

[0050] 4. The ultrasonic transducer packaging device with high-precision matching layer and encapsulation layer thickness control disclosed in this invention reserves a packaging thickness of 1.5 to 2.5 mm on the side of the transducer to ensure that the solder joints and electrode cables are completely covered in the packaging material, reducing the risk of short circuits, water seepage and electrode corrosion in the underwater acoustic environment. Compared with traditional packaging methods, it improves the long-term stability and service life of the transducer in high humidity and underwater environments.

[0051] 5. The ultrasonic transducer encapsulation device for high-precision matching layer and encapsulation layer thickness control disclosed in this invention employs a micrometer-level measuring rod and a bottom lifting plate adjustment mechanism, enabling precise adjustment of the thickness of the encapsulation layer and matching layer. It supports two encapsulation modes: when single-layer encapsulation is required, the outer encapsulation layer can be poured directly into the encapsulation tank in one step; when higher matching precision is required, the matching layer can be cured first in a small-sized encapsulation tank, then demolded and transferred to a large-sized encapsulation tank for peripheral encapsulation, optimizing the structure of the matching layer and encapsulation layer and improving the acoustic performance of the transducer. Compared to traditional custom mold encapsulation methods, this invention can significantly reduce production costs and improve manufacturing consistency and production efficiency. In particular, the design with a 1.5–2.5 mm circumferential allowance in the encapsulation tank ensures that the transducer electrode solder joints are completely encapsulated in the encapsulation material, further improving long-term stability and transducer reliability in underwater acoustic environments. Attached Figure Description

[0052] Figure 1 A schematic diagram of the overall structure of the packaging mold proposed in this invention;

[0053] Figure 2 A partial structural schematic diagram of the packaging mold body 1 proposed in this invention;

[0054] Figure 3 A schematic diagram of the structure of the connecting cover plate 4 proposed in this invention;

[0055] Figure 4 A schematic diagram of the positioning beam 6 proposed in this invention;

[0056] Figure 5 A schematic diagram of the spiral micrometer structure used in this invention;

[0057] Figure 6 Schematic diagram of the height adjustment rod, connecting cover plate, and composite material fixing connection;

[0058] Figure 7 Schematic diagram of the combination of transducer fixing traction device (cover plate assembly) and positioning beam;

[0059] Figure 8 A schematic diagram illustrating the overall installation and use process of the packaging mold device of the present invention;

[0060] Figure 9 Schematic diagram of encapsulation layer or matching layer thickness adjustment;

[0061] Figure 10 Schematic diagram of adding encapsulation layer or matching layer solution;

[0062] Figure 11 A diagram showing the process of removing the packaged item.

[0063] In the diagram, 1—the main body of the packaging mold, 2—the bottom lifting plate, 3—piezoelectric composite material, 4—the connecting cover plate, 5—M6 fastening screw, 6—the positioning beam, 7—the height adjustment rod, 8—the packaging groove, 9—the bottom adjustment hole, 10—the air pressure balance hole, 11—the positioning socket, 12—the height adjustment rod socket, 13—the cable outlet, 14—the cable wiring groove, 15—the cable inlet, 16—the M6 ​​threaded opening, 17—the height adjustment rod sliding passage, 18—the positioning beam pin, 19—the measuring rod, and 20—the micrometer drum. Detailed Implementation

[0064] The following describes the operation of the present invention using two typical processes: one-time single-layer packaging (suitable for general needs requiring only an outer packaging layer) and two-stage packaging (first the matching layer, then the packaging layer, suitable for high-performance needs).

[0065] Example 1: One-time single-layer packaging process

[0066] like Figure 1 As shown, the ultrasonic transducer encapsulation device for high-precision matching layer and encapsulation layer thickness control disclosed in this embodiment includes an encapsulation mold body 1, a bottom lifting plate 2, a piezoelectric composite material and an absorbent backing 3, a metal connecting cover plate 4, an M6 fastening screw 5, a positioning beam 6, and a height adjustment rod 7.

[0067] Figure 1 This is a schematic diagram of the overall structure of the packaging mold proposed in this invention. The connection method is as follows: the bottom lifting plate 2 is placed into the bottom of the packaging groove 8, and then... Figure 7 The positioning beam pin 18 of the structure shown is inserted into the positioning socket 11.

[0068] Figure 2 This is a partial structural diagram of the main body 1 of the packaging mold proposed in this invention, mainly showing the packaging groove 8, the bottom adjustment hole 9, the air pressure balance hole 10, and the positioning socket 11. The packaging groove 8 is used for the packaging operation of the transducer, the bottom adjustment hole 9 is used to insert the measuring rod 19 for thickness control, the air pressure balance hole 10 is used to remove air bubbles and improve the uniformity of the packaging layer, and the positioning socket 11 is used to dock with the positioning beam 6 to ensure stability during the packaging process.

[0069] Figure 3 This is a schematic diagram of the connecting cover plate 4 proposed in this invention, including a height adjustment rod socket 12, a cable outlet 13, a cable routing groove 14, a cable inlet 15, and an M6 threaded port 16. The connecting cover plate 4 is mainly used to fix the transducer assembly and provide cable management functions. The cable is stably led out through the cable routing groove 14 and the outlet 13. The height adjustment rod socket 12 is used to install the height adjustment rod 7 to ensure the stability of the transducer assembly during the packaging process.

[0070] Figure 4 This is a schematic diagram of the positioning beam 6 proposed in this invention, which mainly includes a height adjustment rod sliding port 17 and a positioning beam pin 18. The height adjustment rod sliding port 17 allows the height adjustment rod 7 to slide freely and be fixed, and the positioning beam pin 18 is used to securely insert the positioning beam 6 into the positioning socket 11 on the packaging mold body 1 to form a stable assembly structure and prevent displacement or tilting during the packaging process.

[0071] Figure 5 This is a schematic diagram of the spiral micrometer structure used in this invention, mainly including a measuring rod 19 and a micrometer cylinder 20. The measuring rod 19 adjusts its extension length by rotating the micrometer cylinder 20, thereby changing the height of the bottom lifting plate 2 and achieving precise control of the thickness of the matching layer or encapsulation layer. After the measuring rod 19 is inserted into the bottom adjustment hole 9 of the encapsulation mold body 1, the thickness of the encapsulation layer or matching layer can be controlled within the micrometer range through fine adjustment.

[0072] Step 1, Cable Welding and Preliminary Assembly: Weld the cable to the side electrodes of the piezoelectric composite material (e.g., 16×16 array, net size 23.5mm); the weld height is generally 0.3–1mm. Figure 6 As shown, the cable is passed sequentially through the wiring groove 14 and the inlet 15 of the connecting cover plate 3, and then led out through the outlet 13. The piezoelectric material is then bonded to the cover plate with adhesive to form a single unit; the height adjustment rod 7 is inserted into the socket of the cover plate 12 and screwed into the M6 ​​threaded end 16 to secure it.

[0073] Step 2, Install onto the positioning beam: Refer to... Figure 7The assembled height adjustment rod is inserted into the sliding port 17 of the positioning beam 4 and secured with M6 screws. The entire transducer assembly is then "hoisted" onto the positioning beam, facilitating subsequent docking with the mold body.

[0074] Step 3, Align and Lock the Encapsulation Slot: Insert the positioning beam pin 18 into the positioning socket 11 to form as shown. Figure 8 The overall structure is shown. A suitable encapsulation groove 8 (with a circumferential c=2mm wrapping area) with a depth of 50mm is selected based on the outer dimensions of the piezoelectric material, allowing the cable solder joints to be completely immersed in the subsequent encapsulation resin.

[0075] Step 4, adjust the encapsulation layer thickness using the micrometer probe: Refer to... Figure 9 Insert the measuring rod 19 through the bottom adjustment hole 9, and rotate the differential cylinder 20 to extend the measuring rod by ΔH = 10.3 mm (or other design value). At this time, the bottom lifting plate 2 is lifted by 0.3 mm. After tightening and locking, a casting space of 0.3 mm high is formed between the outside of the transducer and the plate.

[0076] Step 5: Inject encapsulation material and cure: Refer to... Figure 10 Slowly pour the polyurethane solution into the encapsulation tank 8. Due to its high viscosity, it needs to be gently shaken or vacuum degassing should be used to reduce air bubbles. The pressure balance hole 10 keeps the internal pressure consistent with the external pressure. After the encapsulation material self-levels and covers the entire transducer surface, let it stand for a period of time or cure at a specified temperature.

[0077] Step 6, Demolding: Refer to... Figure 11 After curing, the probe can be reinserted or the lock removed, allowing the probe to slowly lift the bottom lifting plate 2, causing the transducer to rise and detach from the slot. This results in a transducer completely encapsulated by an outer layer (e.g., 0.3mm thick), with a circumferential resin margin of c=2mm around the cable solder joints, significantly improving underwater stability. This single encapsulation process achieves micron-level precision control over a single outer layer, suitable for many common applications.

[0078] Implementation Case 2: Two-stage encapsulation, first the matching layer, then the outer encapsulation layer.

[0079] like Figure 1 As shown, the ultrasonic transducer encapsulation device for high-precision matching layer and encapsulation layer thickness control disclosed in this embodiment is implemented in a manner largely the same as in Embodiment 1, with the main differences being the encapsulation sequence and the type of encapsulation slot used. Specifically, as... Figure 8As shown, during the matching layer encapsulation, it is only necessary to insert the positioning beam pin 18 into the positioning socket 11 of the lower half of the encapsulation mold body 1. At this time, the encapsulation slot 8 corresponds to the small slot. During the secondary encapsulation of the outer encapsulation layer, the positioning beam 6 of the upper half is inserted, and the positioning beam pin 18 is inserted into the positioning socket 11 of the upper half of the encapsulation mold body 1. At this time, the encapsulation slot 8 corresponds to the large slot.

[0080] When higher performance or better acoustic bandwidth is required, a two-step method of "matching layer + encapsulation layer" can be used: first, select a relatively small encapsulation tank to pour the matching layer, and after it cures, demold it and then transfer it to a larger tank for final outer encapsulation. Three sets of tanks of different sizes can meet this requirement, that is, in the same group there are pairs of "small tank (slightly smaller in length and width)" + "large tank (about 2mm larger in length and width)".

[0081] Step 1, Casting the Matching Layer in the Small Slot: Select the "Small Slot," with a size slightly larger than the net size of the piezoelectric material by 0.5mm. The total side coverage doesn't need to be excessive (e.g., c = 1mm). Use a micrometer probe to set the target matching layer thickness (e.g., 0.1mm), and pour in the modified epoxy or special resin; vent through the pressure balance hole. After curing, use the probe to lift the bottom lifting plate to demold the transducer containing only the matching layer, obtaining the semi-finished product of "piezoelectric material + matching layer."

[0082] Step two, transfer to a larger groove for peripheral encapsulation: Place the semi-finished product into another "larger groove" (approximately 2mm larger in length and width to accommodate a thicker outer layer) on the same mold body, with a side c = 2mm, allowing the cable solder joints to be completely embedded. Repeat the micrometer probe adjustment to lift the bottom lifting plate to the required height of the encapsulation layer (e.g., 0.3mm to 1mm), then inject polyurethane and cure. After demolding, a multi-layer structure is obtained: "piezoelectric material → matching layer → peripheral encapsulation layer," combining impedance gradient and physical protection.

[0083] Step 3, multi-specification batch production: If different transducer arrays have different sizes, they can also be allocated according to "three groups of one small and one large slot": (1) Group 1: small slot (24mm) + large slot (26mm); (2) Group 2: small slot (26mm) + large slot (28mm); (3) Group 3: small slot (27.5mm) + large slot (29.5mm). In this way, multiple array sizes can be processed at the same time. The matching layer is first poured into the small slot, and then moved to the corresponding large slot for encapsulation layer, which greatly improves the production capacity and consistency.

[0084] This embodiment achieves a significant improvement in the ultrasonic transducer packaging process through structural optimization and precise control, meeting the stringent requirements of different application scenarios for the thickness of the packaging and matching layers. Compared to traditional packaging methods, this embodiment uses an adjustable micrometer probe to control the packaging thickness, ensuring uniform coverage of the matching and packaging layers with a thickness error controlled within ±0.01mm. This results in more precise impedance matching and higher acoustic transmittance of the transducer, thereby improving the transducer's performance stability and signal transmission quality.

[0085] Furthermore, this embodiment utilizes a modular design for the encapsulation slots, making it compatible with both one-time and two-time encapsulation processes. In one-time encapsulation mode, the encapsulation mold can simultaneously process six transducers of different sizes, improving production efficiency. In two-time encapsulation mode, acoustic performance is optimized and the mechanical strength and protective capabilities of the encapsulation layer are enhanced through a small slot matching layer encapsulation and a large slot outer encapsulation layer encapsulation. This design makes this embodiment applicable to ultrasonic transducers of different sizes and with different application requirements, combining versatility and high-precision control.

[0086] The packaging process in this embodiment optimizes the long-term stability of the transducer, making it particularly suitable for fields such as underwater acoustics, medical ultrasound, and industrial non-destructive testing. The packaging layer provides excellent protection, effectively preventing short circuits at solder joints and environmental influences, thus improving the transducer's durability and reliability. Simultaneously, this packaging mold supports mass production; through precise thickness control and standardized packaging processes, consistency in large-scale production is ensured, reducing defect rates and improving production efficiency.

[0087] In summary, this embodiment improves the reliability and applicability of ultrasonic transducer packaging technology through precise adjustment, modular design, and mass production capabilities. Compared with traditional packaging methods, this embodiment has significant advantages in packaging accuracy, production efficiency, applicability, and long-term stability, providing a more optimized packaging solution for high-end ultrasonic applications and possessing broad market application prospects.

[0088] The above detailed description further illustrates the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An ultrasonic transducer encapsulation device with high-precision matching layer and encapsulation layer thickness control, characterized in that: It includes the main body of the packaging mold, the bottom lifting plate, the micrometer measuring rod adjustment mechanism, the packaging groove, the air pressure balance hole and the height adjustment structure; The main body of the encapsulation mold is made of high-strength aluminum alloy or stainless steel, with a thickness of 3~5mm, and is equipped with multiple encapsulation slots to adapt to ultrasonic transducer arrays of different specifications. The encapsulation slot is used to accommodate the ultrasonic transducer and encapsulation material. The size of the encapsulation slot is adjustable and includes single-encapsulation and double-encapsulation modes, supporting step-by-step encapsulation of the matching layer and the encapsulation layer. The bottom lifting plate is used to adjust the thickness of the matching layer and the encapsulation layer. A gap of 0.1~0.3mm is provided between its edge and the wall of the encapsulation groove to ensure adjustment accuracy and avoid shaking or error. The micrometer probe adjustment mechanism is installed at the bottom of the packaging mold and includes a standard micrometer probe and an adjustment knob. The probe extension is controlled by a micrometer cylinder to achieve micrometer-level thickness adjustment between the matching layer and the packaging layer. The pressure balancing hole is located at the bottom of the packaging groove, with a diameter of 5~8mm. It balances the internal and external pressures during the packaging process, reduces the formation of air bubbles, and improves the uniformity of packaging. The height adjustment structure includes a detachable height adjustment rod and a positioning beam, which are connected by threads to fix the transducer structure, prevent the transducer from shifting or tilting during the packaging process, and improve packaging consistency.

2. The packaging device as claimed in claim 1, characterized in that: The encapsulation slot has a two-level structure, including a small encapsulation slot for the mating layer and a large encapsulation slot for the outer encapsulation layer, to accommodate the two-step encapsulation mode of mating layer + outer encapsulation layer and achieve acoustic optimization.

3. The packaging device as described in claim 2, characterized in that: The bottom lifting plate is controlled by a micrometer probe adjustment mechanism. The extension length of the probe can be adjusted by rotating the micrometer cylinder, so that the lifting plate can be raised and lowered within a precision range of 0.01 mm, thereby accurately controlling the thickness of the matching layer and the encapsulation layer.

4. The packaging device as described in claim 3, characterized in that: The measurement accuracy of the micrometer probe is 0.01 mm, ensuring that the error of the matching layer and the encapsulation layer thickness is controlled within ±0.01 mm, thereby improving the acoustic impedance matching effect of the ultrasonic transducer and optimizing the ultrasonic transmission efficiency.

5. The packaging device as described in claim 4, characterized in that: A circumferential allowance of 1.5 to 2.5 mm is reserved in the encapsulation groove to ensure that the transducer electrode solder joints are completely covered in the encapsulation material, preventing short circuits, water seepage, and signal attenuation in underwater or humid environments, and improving the long-term stability of the transducer.

6. The packaging device as described in claim 5, characterized in that: The main body of the packaging mold is equipped with standardized adjustment holes, which can be adapted to micrometer probes of different specifications to meet the matching layer and packaging layer thickness requirements of transducers of different frequencies.

7. The packaging device as claimed in claim 6, characterized in that: A sliding passage is provided between the height adjustment rod and the main body of the packaging mold, which allows the height adjustment rod to remain vertically limited during the packaging process. It is also inserted into the positioning socket through the positioning beam pin to form a highly stable limiting system to prevent the transducer from shifting or tilting.

8. The packaging device as claimed in claim 7, characterized in that: The bottom of the packaging slot is equipped with a bottom adjustment hole with a diameter of 5~6mm. The bottom adjustment hole is used to insert a standard micron measuring rod, and the height of the bottom lifting plate is adjusted by rotating the micron tube to achieve micron-level control of the packaging thickness.

9. The packaging device as claimed in claim 8, characterized in that: The small package slot used for the mating layer and the large package slot used for the outer package layer differ in size by 2mm. It is compatible with ultrasonic transducer arrays of different specifications, including 16×16, 20×20, and 32×32. The frequency range of the transducers is 5 MHz to 15 MHz; The height adjustment structure includes a detachable height adjustment rod and a positioning beam, connected by an M6 thread.

10. A high-precision encapsulation method for an ultrasonic transducer matching layer and encapsulation layer, used for encapsulating an ultrasonic transducer using the encapsulation device as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1, Matching layer encapsulation: Step 1.1: Insert the positioning beam pin into the positioning socket of the lower half of the packaging mold body, select the appropriate small packaging slot, and adjust the micrometer measuring rod to the target matching layer thickness. Step 1.2: Inject matching layer material into the small encapsulation tank and vent air through the air pressure balance hole to reduce air bubbles; Step 1.3: After the matching layer has cured, use a micrometer probe to lift the bottom lifting plate to demold the transducer and obtain the semi-finished product of "piezoelectric material + matching layer"; S2, Encapsulation layer encapsulation: Step 2.1: Insert the positioning beam pin into the positioning socket of the upper half of the packaging mold body, transfer the semi-finished product to the matching large packaging slot, and adjust the micron measuring rod to the target packaging layer thickness. Step 2.2: Inject the encapsulation layer material into the encapsulation tank and balance the pressure through the air pressure balancing hole to avoid uneven encapsulation; Step 2.3: Perform encapsulation and curing. After complete curing, use the micrometer probe to adjust the lifting plate again to demold the transducer and obtain a fully encapsulated transducer. S3, Multi-specification transducer mass packaging: Step 3.1: Select the appropriate encapsulation slot based on the transducer size; Step 3.2: Use a micrometer probe to precisely control the thickness of the matching layer and the encapsulation layer to ensure that all transducer products have consistent encapsulation. Step 3.3: Improve packaging efficiency by performing batch packaging operations.

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