A high-transmittance ultrasonic tomography detector

Abstract

The present invention discloses a high-transmittance ultrasonic tomography detector, which belongs to the field of ultrasonic imaging devices. The detector is composed of at least one ultrasonic transmitting-receiving unit composed of an ultrasonic transmitting transducer and an ultrasonic receiving transducer distributed in opposite directions, wherein the piezoelectric element of the ultrasonic transmitting transducer has a multi-element piezoelectric layer made of single crystal PMN-PT, whose elements are distributed in a planar matrix; the piezoelectric element of the ultrasonic receiving transducer has a multi-element piezoelectric layer made of single crystal PIN-PMN-PT, whose elements are distributed in a convex matrix. The present invention uses high-performance piezoelectric materials to prepare the transmitting and receiving transducers. The piezoelectric layer elements of the transmitting transducer adopt a planar matrix design to produce a uniform sound field, thereby improving the directionality of the transmitted ultrasonic wave; the piezoelectric layer of the receiving transducer adopts a convex design to improve the receiving sensitivity. The present invention takes into account both high resolution and large penetration depth, and is suitable for ultrasonic diagnosis and treatment fields such as deep tissue tumor detection in the human body and intraoperative ultrasonic navigation in the abdomen.

Description

Technical Field

[0001] The present invention relates to the field of medical ultrasonic imaging devices, and in particular to an ultrasonic tomography detector. Background Art

[0002] Traditional ultrasound imaging receives and processes reflected signals to obtain images of the interior of the object being examined. Compared to computed tomography (CT) and magnetic resonance imaging (MRI), it offers advantages such as real-time, non-invasive, radiation-free, and low-cost. However, traditional ultrasound imaging struggles to obtain high-resolution three-dimensional anatomical images of the object being examined, and clinical interpretation of ultrasound images requires significant expertise and technical skills. Ultrasonic tomography, which detects scattered waves around the object to invert images of its internal structure, overcomes these challenges and holds broad application prospects in areas such as intraoperative navigation, disease detection, and nondestructive testing.

[0003] As a core component of an ultrasound tomography system, the performance of an ultrasound detector determines the detection capability of the covered area and the quality of the tomographic image. Numerous advances have been reported in ultrasound tomography detector research both domestically and internationally. For example, in 2020, Martiartu NK. et al. utilized a pair of movable 3.2 MHz, 16-element piezoelectric composite linear ultrasound transducer arrays to achieve breast phantom imaging. By rotating the entire system 23 times, each time placing the receiving transducer in 11 different positions, they fully acquired ultrasound transmission data and improved imaging resolution (Martiartu NK. et al., IEEE Trans. Ultrason. Ferroelectr. Freq. Control 2020, 67, 7). Duric N. and Littrup P. reported a rotatable, 1.5 MHz, 256-element ring transducer based on piezoelectric composites, pioneering in vivo whole-breast imaging and breast mass detection (Duric N., Littrup P., Med. Phys. 2007, 34, 2). Wiskin J. et al. used QT A breast imaging device achieves breast and human bone imaging. The device's ultrasound detector consists of a plane wave transmitting transducer, a 2048-element ultrasonic receiving transducer based on piezoelectric composite materials (for collecting transmitted ultrasonic signals), and three transducers for receiving reflected signals (Wiskin J. et al., Sci. Rep. 2020, 10(1), 1-14). Professor Tan Chao's team at Tianjin University used a ring-shaped ultrasonic tomography detector composed of 16 1-3 lead zirconate titanate (PZT) composite single-element ultrasonic transducers and placed different media in the center area of ​​the detector ring for verification testing (Zhang W. et al., IEEE Trans. Instrum. Meas. 2020, 69, 9). Professor Zhang Wendong's team at North University of China achieved ultrasonic tomography of simulated tumors in breast prostheses based on a pair of 3MHz, 128-element capacitive micromachined ultrasonic transducers (CMUTs) that rely on the rotation of an electric turntable (Pei Y. et al., IEEE SENS. J. 2022, 22, 2).

[0004] To summarize existing ultrasound tomography detectors: Combination detectors based on single-element ultrasonic transducers suffer from low imaging resolution. While increasing the number of transducers and their array elements can improve imaging resolution to some extent, the piezoelectric properties of currently used piezoelectric composite materials limit the transmitted ultrasound's ability to penetrate deep tissues, making ultrasound tomography suitable only for imaging superficial tissues such as the breast. CMUT transducers, constrained by the space between the capacitor plates and limited amplitude, also suffer from the aforementioned issues, resulting in low transmission sensitivity.

[0005] Currently, there are relatively few ultrasonic tomography detectors that combine high imaging resolution with deep penetration depth. Improving the transducer's transmit and receive sensitivity to achieve high-resolution ultrasonic tomography over large spans, as well as designing a dense array of matrix ultrasonic transducers to improve imaging resolution, are pressing challenges facing those skilled in the art.

[0006] PIN-PMN-PT and PMN-PT, single crystal materials with high piezoelectric properties, can be used to prepare highly sensitive matrix ultrasonic transducers, which are expected to solve the bottleneck of existing ultrasonic tomography detectors that are difficult to achieve deep penetration under high operating frequency conditions. Summary of the Invention

[0007] The purpose of the present invention is to propose a high-transmittance ultrasonic tomography detector structural design and high-performance piezoelectric single crystal material design for high-sensitivity emission and high-sensitivity reception of ultrasonic waves to achieve large-span high-resolution ultrasonic tomography function.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] The present invention provides a high-transmittance ultrasonic tomography detector, which comprises at least one ultrasonic transmitting-ultrasonic receiving unit, wherein the ultrasonic transmitting-ultrasonic receiving unit is composed of an ultrasonic transmitting transducer and an ultrasonic receiving transducer arranged in an opposing distribution, wherein the piezoelectric element of the ultrasonic transmitting transducer has a multi-element piezoelectric layer with array elements distributed in a planar matrix, and the piezoelectric material is single crystal PMN-PT; the piezoelectric element of the ultrasonic receiving transducer has a multi-element piezoelectric layer with array elements distributed in a convex matrix, and the piezoelectric material is single crystal PIN-PMN-PT.

[0010] The ultrasonic transmitter and receiver unit comprises an ultrasonic transmitter transducer for transmitting ultrasonic waves, and a flat piezoelectric layer. The ultrasonic receiver transducer, for receiving transmitted ultrasonic signals after they have passed through the object being inspected, has a convex piezoelectric layer. The flat piezoelectric layer of the ultrasonic transmitter transducer is positioned opposite the convex piezoelectric layer of the ultrasonic receiver transducer.

[0011] The operating frequency of the single crystal PMN-PT is in the range of 2-6 MHz, and the bandwidth is greater than 65%. As an advantage, the piezoelectric material used in the piezoelectric layer of the ultrasonic transmitter transducer is single crystal PMN-32% PT, and the chemical formula is: Pb(Mg 1 / 3 Nb 2 / 3 )O3-32% PbTiO3, with high piezoelectric coefficient, d 33 =1620pC / N, which is beneficial to improving the transmission sensitivity of the ultrasonic transmitting transducer.

[0012] The operating frequency of the single crystal PIN-PMN-PT is in the range of 2-6MHz, and the bandwidth is greater than 65%. As an advantage, the piezoelectric material used in the piezoelectric layer of the ultrasonic receiving transducer is single crystal PIN33%-PMN-PT, and the chemical formula is: 33% Pb(In 1 / 2Nb 1 / 2 )O3-Pb(Mg 1 / 3 Nb 2 / 3 )O3-PbTiO3, has a high piezoelectric constant and a relatively low dielectric constant, the piezoelectric constant d 33 It is 1338pC / N, and the relative dielectric constant ε3T3 is 4532, which is beneficial to improving the receiving sensitivity of the ultrasonic receiving transducer.

[0013] Preferably, the number of piezoelectric layer elements of the ultrasonic transmitting transducer and the ultrasonic receiving transducer is no less than 256. The present invention adopts a transducer design with no less than 256 elements and a transducer bandwidth greater than 65%, which can improve the resolution of ultrasonic tomography.

[0014] Preferably, the number of piezoelectric layer array elements is set to 128×2, 64×4 or 32×32.

[0015] Preferably, the matrix types of the piezoelectric layers of the ultrasonic transmitting transducer and the ultrasonic receiving transducer are both 1.5D or 2D.

[0016] Preferably, the matrix type of the piezoelectric layer of the ultrasonic transmitting transducer and the ultrasonic receiving transducer is 1.5D, and the number of array elements is 128×2; the array element width is 0.45mm, the array element center distance is 0.55mm, the length of the second row of array elements is 5mm, the length of the first and third rows of array elements is 2.5mm, the widths of the longitudinal and transverse grooves of the array elements are 0.10mm and 0.25mm respectively; the convex curvature radius of the piezoelectric layer of the ultrasonic receiving transducer is 55-65cm.

[0017] Preferably, the matrix type of the piezoelectric layer of the ultrasonic transmitting transducer and the ultrasonic receiving transducer is 1.5D, and the number of array elements is 64×4; the array element width is 0.50 mm, the array element center distance is 0.60 mm, the length of the 4th column of array elements is 5 mm, the length of the 1st, 2nd, 3rd, 5th, 6th and 7th columns of array elements is 2.5 mm, the widths of the longitudinal and transverse grooves of the array elements are 0.10 mm and 0.30 mm respectively; the curvature radius of the convex surface of the piezoelectric layer of the ultrasonic receiving transducer is 50-60 cm.

[0018] Preferably, the matrix type of the piezoelectric layer of the ultrasonic transmitting transducer and the ultrasonic receiving transducer is 2D, and the number of array elements is 32×32; the array element width is 0.40 mm, the array element center distance is 0.50 mm, the array element length is 5 mm, and the widths of the longitudinal and transverse grooves of the array elements are 0.10 mm and 0.20 mm respectively; the convex curvature radius of the piezoelectric layer of the ultrasonic receiving transducer is 45-55 cm.

[0019] To increase the rate of ultrasonic tomography, the detector is equipped with two or more ultrasonic transmitter-receiver units to expand the detection coverage. Alternatively, detection can be performed by rotating the ultrasonic transmitter-receiver units using a rotating device. Furthermore, the rotating device is a precision mechanical moving component, driven by a stepper motor to control the movement of the transmitting and receiving transducers, maintaining them in an opposing position. The use of a precision mechanical moving component reduces the number of transducers and their cost while expanding the detection coverage area.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The present invention uses high-performance single-crystal piezoelectric material PMN-PT to prepare the transmitting transducer, which has a high piezoelectric constant, and uses single-crystal piezoelectric material PIN-PMN-PT to prepare the receiving transducer, which has a relatively low dielectric constant; the piezoelectric material used has high acoustic-to-electric and electro-acoustic conversion efficiency, strong ultrasonic transmission signal, deep penetration into human tissue, and high receiving sensitivity, which is conducive to improving the clarity of ultrasonic tomography.

[0022] (2) The matrix ultrasonic transducer used for transmission of the present invention adopts a planar matrix design, which can produce a more uniform sound field and improve the directionality of the transmitted ultrasonic waves; the matrix ultrasonic transducer used for reception adopts a convex design with a larger surface area, which has a better focusing effect when receiving ultrasonic waves and can improve the receiving sensitivity.

[0023] (3) The present invention adopts a multi-element matrix structure design and a transducer bandwidth greater than 65%, which can improve the resolution of ultrasonic tomography.

[0024] (4) The present invention takes into account both high resolution and large penetration depth, and is suitable for digital diagnosis and treatment fields such as ultrasound imaging detection of tumors in deep tissues of the human body and ultrasound navigation during abdominal surgery. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the overall design of the ultrasonic tomography detector. In the figure, 1 and 3 are planar matrix ultrasonic transmitting transducers; 2 and 4 are convex matrix ultrasonic receiving transducers; and 5 is a precision mechanical moving component.

[0026] Figure 2 Schematic diagram of the piezoelectric layer design of a 128×2 element planar matrix ultrasonic transmitting transducer.

[0027] Figure 3 Schematic diagram of the piezoelectric layer design of a 128×2 element convex matrix ultrasound receiving transducer.

[0028] Figure 4 This is a schematic diagram of the circuit connection design of each element of the 128×2 array ultrasonic transducer.

[0029] Figure 5 This is a diagram showing the working principle of the ultrasonic tomography detector.

[0030] Figure 6 This is the imaging diagram of the 128×2 array element ultrasonic transmitting-receiving detector.

[0031] Figure 7 3D reconstructed image of ultrasonic tomography using a 128×2 array element ultrasonic transmitter-receiver detector.

[0032] Figure 8 Schematic diagram of the piezoelectric layer design of a 64×4 element planar matrix ultrasonic transmitting transducer.

[0033] Figure 9 Schematic diagram of the piezoelectric layer design of the 64×4 element convex matrix ultrasound receiving transducer.

[0034] Figure 10 This is a schematic diagram of the circuit connection design of each element of the 64×4 array ultrasonic transducer.

[0035] Figure 11 This is the imaging image of the 64×4 array element ultrasonic transmitting-receiving detector.

[0036] Figure 12 Schematic diagram of the piezoelectric layer design of a 32×32 element planar matrix ultrasonic transmitting transducer.

[0037] Figure 13 Schematic diagram of the piezoelectric layer design for a 32×32 element convex matrix ultrasound receiving transducer.

[0038] Figure 14 This is a schematic diagram of the circuit connection design of each element of a 32×32 array ultrasonic transducer.

[0039] Figure 15 This is the imaging diagram of the 32×32 array element ultrasonic transmitting-receiving detector.

[0040] Figure 16 This is the imaging diagram of the 128×2 array element planar ultrasonic transmitter-planar ultrasonic receiver detector. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with specific examples. The following examples are only used to illustrate the present invention and are not intended to limit the scope of application of the present invention. The technical features of the various embodiments of the present invention can be combined accordingly without conflicting with each other. Without departing from the spirit and essence of the present invention, any modification or replacement of the method, steps or conditions of the present invention falls within the scope of the present invention.

[0042] The piezoelectric materials PMN-32% PT, PIN33%-PMN-PT, PMN-28% PT, and PIN24%-PMN-PT used in the following specific examples are commercially available from CTS Corporation of the United States.

[0043] Example 1

[0044] This embodiment provides a high-transmittance ultrasonic tomography detector, which comprises two ultrasonic transmitting-receiving units, such as Figure 1 As shown. The ultrasonic transmitting-receiving unit is composed of an ultrasonic transmitting transducer 1 (3) and an ultrasonic receiving transducer 2 (4) arranged in an opposite distribution. The ultrasonic transmitting-receiving unit is mounted on a precision mechanical moving component 5. The piezoelectric element of the ultrasonic transmitting transducer has a multi-element piezoelectric layer with elements distributed in a planar matrix, and the piezoelectric material is single crystal PMN-PT; the piezoelectric element of the ultrasonic receiving transducer has a multi-element piezoelectric layer with elements distributed in a convex matrix, and the piezoelectric material is single crystal PIN-PMN-PT.

[0045] Specifically, the piezoelectric material of the ultrasonic transmitting transducer is PMN-32% PT, and the piezoelectric constant d33 It is 1620pC / N.

[0046] Specifically, the piezoelectric material of the ultrasonic receiving transducer is PIN33%-PMN-PT, which has a high piezoelectric constant, d 33 It is 1338pC / N and has a relatively low dielectric constant, ε3T3 is 4532.

[0047] Specifically, such as Figure 2 As shown, the piezoelectric layer matrix type of the ultrasonic transmitting transducer is 1.5D, and the number of array elements is 128×2. The array element width w T is 0.45mm, the array element center distance P T is 0.55mm, and the length of the second row of array elements is E TC is 5mm, the length of the first and third rows of array elements is E TS The longitudinal groove of the array element is 2.5mm. T1 and transverse grooves g T2 They are 0.10mm and 0.25mm respectively.

[0048] Specifically, such as Figure 3 As shown, the piezoelectric layer matrix type of the ultrasonic receiving transducer is 1.5D, and the number of array elements is 128×2. The array element width w C is 0.45mm, the array element center distance P C is 0.55mm, and the length of the second row of array elements is E CC is 5mm, the length of the first and third rows of array elements is E CS The longitudinal groove of the array element is 2.5mm. C1 and transverse grooves g C2 The curvature radius R of the piezoelectric layer is 55 cm. The convex surface serves as the signal receiving surface.

[0049] Specifically, the circuit connection mode of each element of the planar matrix ultrasonic transmitting transducer and the convex matrix ultrasonic receiving transducer is as follows: Figure 4 As shown, the first and third columns of array elements are connected in series to form one array element, forming a total of 256 independent array elements.

[0050] The working principle of the above-mentioned high-transmittance ultrasonic tomography detector is as follows:

[0051] This detector mounts the ultrasonic transducer on a precision mechanical moving component and uses a stepper motor to control the movement of the transducer to obtain the projection of the object to be measured at different angles. The ultrasonic signal is collected using the transmission mode, such as Figure 5Afterwards, the collected ultrasonic signal is subjected to relative attenuation calculation to obtain the attenuation projection distribution. Furthermore, the time difference between the ultrasonic wave reaching the receiving transducer is used to obtain the sound velocity projection distribution at different angles. High-resolution ultrasonic computed tomography images can then be reconstructed using the filtered back projection method.

[0052] Test results:

[0053] The planar matrix ultrasonic transmitting transducer is placed in a water tank. A 3.5MHz immersion probe was used for receiving, and the distance between the transducer and the probe was 12cm. The measured operating frequency of the transmitting transducer was 3.17MHz, the bandwidth was 76.88%, and the sensitivity was -65.92dB.

[0054] The convex matrix ultrasonic receiving transducer is placed in a water tank, and the A 3.5MHz immersion probe was used for transmission, and the distance between the transducer and the probe was 12cm. The measured operating frequency of the receiving transducer was 3.16MHz, the bandwidth was 102.11%, and the sensitivity was -69.72dB.

[0055] The planar matrix ultrasound transmitting transducer and the convex matrix ultrasound receiving transducer are placed 549 Ultrasound imaging can be performed at both ends of the phantom, and the penetration depth can reach 11.8 cm. Figure 6 shown.

[0056] The planar matrix ultrasonic transmitting transducer and the convex matrix ultrasonic receiving transducer are placed at both ends of the capillary sample (placed in a water tank) for imaging. The imaging results are as follows: Figure 7 As shown, it can be seen that ultrasound tomography can clearly show the shape and outline of the capillary.

[0057] Example 2

[0058] This embodiment provides a high-transmittance ultrasonic tomography detector, which comprises an ultrasonic transmitting-receiving unit, which is composed of an ultrasonic transmitting transducer and an ultrasonic receiving transducer arranged in an opposing distribution. The piezoelectric element of the ultrasonic transmitting transducer has a multi-element piezoelectric layer with array elements distributed in a planar matrix, and the piezoelectric material is single-crystal PMN-PT; the piezoelectric element of the ultrasonic receiving transducer has a multi-element piezoelectric layer with array elements distributed in a convex matrix, and the piezoelectric material is single-crystal PIN-PMN-PT.

[0059] Specifically, the piezoelectric material of the ultrasonic transmitting transducer is PMN-32% PT.

[0060] Specifically, the piezoelectric material of the ultrasonic receiving transducer adopts PIN33%-PMN-PT.

[0061] Specifically, such as Figure 8 As shown, the piezoelectric layer matrix type of the ultrasonic transmitting transducer is 1.5D, and the number of array elements is 64×4. The array element width w T is 0.50mm, the array element center distance P T is 0.60 mm, and the length of the fourth row of array elements is E TC The length of the first, second, third, fifth, sixth and seventh rows of array elements is 5mm. TS The longitudinal groove of the array element is 2.5mm. T1 and transverse grooves g T2 0.10mm and 0.30mm respectively.

[0062] Specifically, such as Figure 9 As shown, the piezoelectric layer matrix type of the ultrasonic receiving transducer is 1.5D, and the number of array elements is 64×4. The array element width w C is 0.50mm, the array element center distance P C is 0.60 mm, and the length of the fourth row of array elements is E CC The length of the first, second, third, fifth, sixth and seventh rows of array elements is 5mm. CS The longitudinal groove of the array element is 2.5mm. C1 and transverse grooves g C2 The curvature radius R of the piezoelectric layer is 50 cm. The convex surface serves as the signal receiving surface.

[0063] Specifically, the circuit connection mode of each element of the planar matrix ultrasonic transmitting transducer and the convex matrix ultrasonic receiving transducer is as follows: Figure 10 As shown, the left and right symmetrical array elements are connected in series to form an array element, forming a total of 256 independent array elements.

[0064] Test results:

[0065] The planar matrix ultrasonic transmitting transducer is placed in a water tank. A 3.5MHz immersion probe was used for receiving, and the distance between the transducer and the probe was 12cm. The measured operating frequency of the transmitting transducer was 3.21MHz, the bandwidth was 76.05%, and the sensitivity was -66.45dB.

[0066] The convex matrix ultrasonic receiving transducer is placed in a water tank, and the A 3.5MHz immersion probe was used for transmission, and the distance between the transducer and the probe was 12cm. The operating frequency of the receiving transducer was measured to be 3.15MHz, the bandwidth was 100.83%, and the sensitivity was -70.59dB.

[0067] The planar matrix ultrasound transmitting transducer and the convex matrix ultrasound receiving transducer are placed 549 Ultrasound imaging can be performed at both ends of the phantom, and the penetration depth can reach 12.9 cm. Figure 11 shown.

[0068] Example 3

[0069] This embodiment provides a high-transmittance ultrasonic tomography detector, which comprises an ultrasonic transmitting-receiving unit, which is composed of an ultrasonic transmitting transducer and an ultrasonic receiving transducer arranged in an opposing distribution. The piezoelectric element of the ultrasonic transmitting transducer has a multi-element piezoelectric layer with array elements distributed in a planar matrix, and the piezoelectric material is single-crystal PMN-PT; the piezoelectric element of the ultrasonic receiving transducer has a multi-element piezoelectric layer with array elements distributed in a convex matrix, and the piezoelectric material is single-crystal PIN-PMN-PT.

[0070] Specifically, the piezoelectric material of the ultrasonic transmitting transducer is PMN-32% PT.

[0071] Specifically, the piezoelectric material of the ultrasonic receiving transducer adopts PIN33%-PMN-PT.

[0072] Specifically, such as Figure 12 As shown, the piezoelectric layer matrix type of the ultrasonic transmitting transducer is 2D, and the number of array elements is 32×32. The array element width w T is 0.40mm, the array element center distance P T is 0.50mm, the array element length E T 5mm, the longitudinal groove of the array element g T1 and transverse grooves g T2 0.10mm and 0.20mm respectively.

[0073] Specifically, such as Figure 13 As shown, the piezoelectric layer matrix type of the ultrasonic receiving transducer is 2D, and the number of array elements is 32×32. The array element width w C is 0.40mm, the array element center distance P C is 0.50mm, the array element length E C 5mm, the longitudinal groove of the array element g C1 and transverse grooves g C2 The curvature radius R of the piezoelectric layer is 45 cm. The convex surface serves as the signal receiving surface.

[0074] Specifically, the circuit connection mode of each element of the planar matrix ultrasonic transmitting transducer and the convex matrix ultrasonic receiving transducer is as follows: Figure 14 As shown, each unit is independent, forming a total of 1024 independent array elements.

[0075] Test results:

[0076] The planar matrix ultrasonic transmitting transducer is placed in a water tank. A 3.5MHz immersion probe was used for receiving, and the distance between the transducer and the probe was 12cm. The measured operating frequency of the transmitting transducer was 3.14MHz, the bandwidth was 78.66%, and the sensitivity was -66.19dB.

[0077] The convex matrix ultrasonic receiving transducer is placed in a water tank, and the A 3.5MHz immersion probe was used for transmission, and the distance between the transducer and the probe was 12cm. The operating frequency of the receiving transducer was measured to be 2.98MHz, the bandwidth was 94.86%, and the sensitivity was -71.35dB.

[0078] The planar matrix ultrasound transmitting transducer and the convex matrix ultrasound receiving transducer are placed 549 Ultrasound imaging can be performed at both ends of the body membrane, and the penetration depth can reach 14 cm, such as Figure 15 shown.

[0079] Comparative Example 1

[0080] This comparative example provides an imaging comparison using a planar ultrasonic transducer as both an ultrasonic transmitting and receiving device.

[0081] Specifically, the transducer piezoelectric layer matrix type is 1.5D, and the number of array elements is 128×2. The array element width w T is 0.45mm, the array element center distance P T is 0.55mm, and the length of the second row of array elements is E TC is 5mm, the length of the first and third rows of array elements is E TS The longitudinal groove of the array element is 2.5mm. T1 and transverse grooves g T2 The piezoelectric material of the ultrasonic transmitting transducer is PMN-32% PT. The piezoelectric material of the ultrasonic receiving transducer is PIN33%-PMN-PT.

[0082] The planar matrix ultrasound transmitting transducer and the planar matrix ultrasound receiving transducer are placed 549 Ultrasound imaging is performed at both ends of the body membrane, and the imaging results are as follows Figure 16 As shown, the imaging resolution is lower than that of Example 1.

[0083] Comparative Example 2

[0084] This comparative example provides a comparison of the emission sensitivities of ultrasonic transmitting transducers using the same design parameters but different piezoelectric materials.

[0085] Specifically, the piezoelectric layer matrix type of the ultrasonic transmitting transducer is 1.5D, and the number of array elements is 64×4. The array element width w Tis 0.50mm, the array element center distance P T is 0.60 mm, and the length of the fourth row of array elements is E TC The length of the first, second, third, fifth, sixth and seventh rows of array elements is 5mm. TS The longitudinal groove of the array element is 2.5mm. T1 and transverse grooves g T2 0.10mm and 0.30mm respectively.

[0086] Transducer emission sensitivity test: Place the planar matrix ultrasonic emission transducer in a water tank and use The 3.5MHz immersion probe is used for receiving, the distance between the transducer and the probe is 12 cm, and the transmitting sensitivity of the transmitting transducer is measured.

[0087] Specifically, the emission sensitivity of the piezoelectric material PMN-32% PT is -66.45 dB.

[0088] Specifically, the emission sensitivity of the piezoelectric material PMN-28% PT is -57.44 dB.

[0089] Comparative Example 3

[0090] This comparative example provides a comparison of the receiving sensitivities of ultrasonic receiving transducers using the same design parameters but different piezoelectric materials.

[0091] Specifically, the piezoelectric layer matrix type of the ultrasonic receiving transducer is 2D, and the number of array elements is 32×32. The array element width w C is 0.40mm, the array element center distance P C is 0.50mm, the array element length E C 5mm, the longitudinal groove of the array element g C1 and transverse grooves g C2 The curvature radius R of the piezoelectric layer is 45 cm. The convex surface serves as the signal receiving surface.

[0092] Transducer receiving sensitivity test: Place the convex matrix ultrasonic receiving transducer in the water tank and use The 3.5MHz immersion probe is used for transmission, and the distance between the transducer and the probe is 12 cm. The receiving sensitivity of the receiving transducer is tested.

[0093] Specifically, the receiving sensitivity of the transducer using the piezoelectric material PIN33%-PMN-PT is -71.35 dB.

[0094] Specifically, the receiving sensitivity of the transducer using the piezoelectric material PIN24%-PMN-PT is -65.83 dB.

[0095] In summary, the present invention provides a high-transmittance ultrasonic tomography detector comprising at least one ultrasonic transmitter-receiver unit, the ultrasonic transmitter-receiver unit comprising an ultrasonic transmitter transducer and an ultrasonic receiver transducer arranged in opposing configurations. The piezoelectric element of the ultrasonic transmitter transducer comprises a multi-element piezoelectric layer with elements arranged in a planar matrix, the piezoelectric material being single-crystal PMN-PT; the piezoelectric element of the ultrasonic receiver transducer comprises a multi-element piezoelectric layer with elements arranged in a convex matrix, the piezoelectric material being single-crystal PIN-PMN-PT. The detector operates at a frequency between 2 and 6 MHz and has a bandwidth greater than 65%. The high-transmittance ultrasonic tomography detector provided by the present invention has a simple structure and high transmit and receive sensitivity, making it suitable for use in medical fields such as deep tissue tumor detection and intraoperative ultrasonic navigation.

[0096] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Persons skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent substitution or equivalent transformation falls within the scope of protection of the present invention.

Claims

1. A high-transmittance ultrasonic tomography detector, characterized in that: The ultrasonic transmitter-receiver comprises at least one ultrasonic transmitter-receiver unit, which is composed of an ultrasonic transmitter transducer and an ultrasonic receiver transducer arranged in an opposing manner. The piezoelectric element of the ultrasonic transmitter transducer comprises a multi-element piezoelectric layer with elements arranged in a planar matrix, and the piezoelectric material is single-crystal PMN-32% PT. The piezoelectric element of the ultrasonic receiver transducer comprises a multi-element piezoelectric layer with elements arranged in a convex matrix, and the piezoelectric material is single-crystal PIN33%-PMN-PT. The operating frequency of the single-crystal PMN-32% PT and the single-crystal PIN33%-PMN-PT are in the range of 2-6 MHz, and the bandwidth is greater than 65%. The matrix type of the piezoelectric layer of the ultrasonic transmitting transducer and the ultrasonic receiving transducer is 1.5D, the number of array elements is 128×2; the array element width is 0.45mm, the array element center distance is 0.55mm, the length of the second row of array elements is 5mm, the length of the first and third rows of array elements is 2.5mm, the widths of the longitudinal and transverse partitions of the array elements are 0.10mm and 0.25mm respectively; the curvature radius of the convex surface of the piezoelectric layer of the ultrasonic receiving transducer is 55-65cm; Alternatively, the matrix type of the piezoelectric layer of the ultrasonic transmitting transducer and the ultrasonic receiving transducer is 1.5D, the number of array elements is 64×4; the array element width is 0.50 mm, the array element center distance is 0.60 mm, the length of the fourth row of array elements is 5 mm, the length of the first, second, third, fifth, sixth, and seventh rows of array elements is 2.5 mm, the widths of the longitudinal and transverse partition grooves of the array elements are 0.10 mm and 0.30 mm respectively; the curvature radius of the convex surface of the piezoelectric layer of the ultrasonic receiving transducer is 50-60 cm; Alternatively, the matrix type of the piezoelectric layer of the ultrasonic transmitting transducer and the ultrasonic receiving transducer is 2D, the number of array elements is 32×32; the array element width is 0.40 mm, the array element center distance is 0.50 mm, the array element length is 5 mm, the widths of the longitudinal and transverse grooves of the array element are 0.10 mm and 0.20 mm respectively; the convex curvature radius of the piezoelectric layer of the ultrasonic receiving transducer is 45-55 cm.

2. The high-transmittance ultrasonic tomography detector according to claim 1, wherein: The detector is provided with two or more ultrasonic transmitting and receiving units.

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