Transparent PMN-PT ultrasonic array transducer and photoacoustic imaging probe
By adopting transparent PMN-PT ultrasonic array transducer, a multimodal composite probe that can realize ultrasonic, photoacoustic and optical imaging was built, which solved the problem that existing photoacoustic probes cannot achieve pure optical imaging, optical coherence and fluorescence imaging, and improved the sensitivity and performance of imaging.
Patent Information
- Application Number
- CN202421040750.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-14
- Publication Date
- 2025-03-25
- Estimated Expiration
- 2034-05-14
AI Technical Summary
Due to structural limitations, existing photoacoustic imaging probes cannot achieve pure optical imaging, optical coherence and fluorescence imaging, and the piezoelectric performance of transparent photoacoustic array probes is average, which affects the sensitivity and performance of imaging.
A transparent PMN-PT ultrasonic array transducer is adopted, which includes a multi-array linear array or phased array transparent PMN-PT single crystal, a transparent backing layer, a transparent matching layer and a transparent conductive film to form a transparent conductive circuit to realize multimodal composite probe for ultrasonic, photoacoustic and optical imaging.
A multimodal composite probe for ultrasonic, photoacoustic and optical imaging is realized, which improves the intensity of photoacoustic signal, avoids near-field blind spots, enhances the sensitivity and performance of imaging, can operate simultaneously, and is highly practical.
Smart Images
Figure CN222657042U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of photoacoustic imaging, and in particular relates to a transparent PMN-PT ultrasonic array transducer, and also relates to a photoacoustic imaging probe. Background Art
[0002] Ultrasonic imaging and optical imaging are currently important imaging methods for clinical diagnosis of various diseases and scientific experiments, and are widely used. Photoacoustic imaging (PAI), which combines the imaging advantages of both, is a new non-invasive biomedical imaging method developed in recent years. When a short-pulse laser is irradiated into biological tissue, the tissue absorbs light to generate thermal expansion and contraction to produce an ultrasonic signal. The corresponding PAI image can be obtained by collecting and processing the relevant signals. PAI combines the advantages of high selectivity in pure optical tissue imaging and deep penetration in pure ultrasonic tissue imaging, and can obtain high-resolution and high-contrast tissue functional images. It avoids the influence of light scattering in principle, breaks through the depth of high-resolution optical imaging, and has excellent application prospects.
[0003] However, since the signal generated by the photoacoustic signal is an ultrasonic signal, the main detector currently used in photoacoustic imaging is the ultrasonic probe, which uses the piezoelectric effect to convert the photoacoustic signal into an electrical signal for the system to process and image. Therefore, there have been studies and related products that combine photoacoustic imaging with ultrasonic imaging to achieve dual-modal imaging, such as the Vevo-LAZR system of Visualsonics; but due to the limitations of the probe, it cannot complete pure optical imaging, nor can it be extended to optical coherence, fluorescence imaging, etc. In short, the existing photoacoustic probe is mainly placed sideways, with the ultrasonic probe in the middle and the laser irradiated on both sides of the probe through the optical fiber. Commercial products will also enclose both in the same probe housing, but the basic structure is the same. This method will cause blind shadows in the near field of the probe due to the lack of laser irradiation, and the laser energy cannot be fully concentrated in the detection area of the probe.
[0004] In order to overcome the shortcomings of side-mounted photoacoustic probes, researchers have used transparent piezoelectric materials such as lithium niobate to make transparent ultrasonic probes and direct photoacoustic probes, which can concentrate laser energy on the detection area of the ultrasonic probe, avoid the near-field blind spot, and improve the photoacoustic signal intensity. However, the current transparent photoacoustic array probes mainly use lithium niobate, which has general piezoelectric properties, affecting the detection sensitivity and performance of photoacoustic imaging and ultrasonic imaging.
[0005] In recent years, researchers have used alternating electric fields to polarize PMN-PT crystals, eliminating the ferroelectric domain walls that scatter light, thereby obtaining PMN-PT piezoelectric single crystal materials with high piezoelectric coefficients (greater than 2100pC / N), high electro-optic coefficients (220pm / V) and theoretical limit transmittance (DOI: 10.1038 / s41586-019-1891-y10.1038 / d41586-020-00038-z). This makes it possible to develop transparent photoacoustic probes based on high-performance piezoelectric materials.
[0006] However, currently transparent photoacoustic probes based on PMN-PT are mainly single-element probes, which can only perform two-dimensional or three-dimensional imaging through mechanical scanning and other methods, and have low efficiency. At the same time, transparent photoacoustic array probes are mainly used for photoacoustic or integrated ultrasound imaging, and there is no integrated optical multi-modal composite probe. Utility Model Content
[0007] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide a new transparent PMN-PT ultrasonic array transducer.
[0008] The invention also relates to a photoacoustic imaging probe.
[0009] In order to solve the above technical problems, the utility model adopts the following technical solutions:
[0010] A transparent PMN-PT ultrasonic array transducer comprises a transparent PMN-PT single crystal, wherein the transparent PMN-PT single crystal is a multi-element linear array or phased array, and the transducer further comprises a transparent backing layer and a transparent matching layer located on both end surfaces of the transparent PMN-PT single crystal; and a transparent conductive film located between the transparent backing layer and the transparent PMN-PT single crystal, and between the transparent PMN-PT single crystal and the transparent matching layer, wherein the transparent conductive film serves as an electrode and forms a transparent conductive circuit with the transparent PMN-PT single crystal, and forms a solder pad at the end for cable welding or connector connection with the cable.
[0011] Preferably, the transparent conductive film is indium tin oxide, aluminum-doped zinc oxide, fluorine-doped tin oxide or antimony-doped tin oxide. In short, the upper and lower surfaces are sputtered with transparent conductive films as electrodes, such as indium tin oxide (ITO, In2O3:Sn), aluminum-doped zinc oxide (AZO, ZnO:Al), fluorine-doped tin oxide (FTO, SnO2:F), antimony-doped tin oxide (ATO, Sn2O:Sb), etc.
[0012] Preferably, the number of array elements is ≥8, and the center frequency is ≥0.5 MHz.
[0013] According to a specific implementation and preferred aspect of the utility model, the transparent backing layer is transparent tempered glass. In short, the surface where the transparent backing layer is connected to the transparent PMN-PT single crystal uses processes such as photolithography and sputtering to form a transparent conductive circuit distributed in an array with equal intervals, and forms a pad at the end for cable welding or connector connection with the cable, and is connected to the system host through the cable.
[0014] According to another specific implementation and preferred aspect of the utility model, the transparent matching layer is a polymer epoxy or acrylic plastic, and the thickness of the transparent matching layer is less than or equal to 1 / 4 of the thickness of the wavelength of the working frequency of the probe. A transparent conductive film layer is also plated on the side connected to the transparent PMN-PT as an electrode, and the thickness of the matching layer is about 1 / 4 of the thickness of the wavelength of the working frequency of the probe. When making the transducer array, the transparent backing transparent conductive circuit part and the transparent PMN-PT are first tightly bonded with transparent epoxy resin, and then a cutting machine is used to cut according to the set transducer array size to form an array structure, and then the transparent matching layer is bonded to the upper surface of the PMN-PT with transparent epoxy resin, and the conductive layer is used to connect the cut PMN-PT arrays to form a common ground connection, and connected to the common ground cable at the edge.
[0015] Preferably, a layer of transparent Parylene film is formed on the surface of the transparent matching layer. The Parylene film (which can be purchased directly on the market and is a conventional product) is mainly used to improve the acoustic matching coupling effect.
[0016] Another technical solution of the utility model is: a photoacoustic imaging probe, which includes a shell, a transducer, and a photoacoustic system, wherein the transducer is a transparent PMN-PT ultrasonic array transducer, and the photoacoustic system includes an ultrasonic imaging component, a photoacoustic imaging component, and an optical imaging component, wherein in the ultrasonic imaging mode, the transparent PMN-PT ultrasonic array transducer is used to transmit and receive ultrasonic waves; in the photoacoustic imaging mode, the transparent PMN-PT ultrasonic array transducer can receive the photoacoustic signal generated by the target; in the optical imaging mode, the transparent PMN-PT ultrasonic array transducer is a transparent protective window.
[0017] Preferably, the photoacoustic imaging component includes a photoacoustic optical fiber and a fiber optic projection unit, and the fiber optic projection unit includes a beam expander and a confocal convex lens. The laser is guided by the optical fiber and then expanded and collimated before being irradiated to the transparent PMN-PT ultrasonic array transducer. In short, the laser is guided by the optical fiber and irradiated to the double concave lens for beam expansion, and then collimated by the confocal convex lens, and then vertically irradiated to the target through the transparent array transducer, providing uniform and stable laser irradiation for photoacoustic imaging. In some specific embodiments, the end of the photoacoustic optical fiber is connected to a short pulse laser for photoacoustic imaging, which mainly transmits the near-infrared short pulse laser required for photoacoustic imaging, such as Nd:YAG1064nm, near-infrared pulse laser with adjustable wavelength of OPO laser, etc.
[0018] Preferably, the optical imaging assembly includes an imaging optical fiber, a dichroic mirror, and a CMOS sensor. After the light beam passes through the dichroic mirror and the transparent PMN-PT ultrasonic array transducer, the CMOS sensor transmits a signal to perform optical imaging. Specifically, the dichroic mirror is a DM dichroic mirror, which is located in the middle of the probe. When the laser is incident at 45 degrees or at a large angle, the light path direction of different spectra is changed according to the different spectra of the incident light source. In the present application, when the pulsed laser used for photoacoustic imaging is irradiated on the DM, since its wavelength is greater than 800nm, the laser completely passes through the DM without reflection, and when the white light (380-750nm) for optical imaging is irradiated on the DM, since its wavelength is less than 800nm, the light irradiated on the DM is totally reflected and all irradiated on the target, and the light reflected back by the target is captured by the CMOS through the DM mirror. At the same time, the imaging optical fiber mainly transmits the continuous visible light required for optical imaging for optical imaging, such as white light excited by light sources such as LEDs and xenon lamps.
[0019] Preferably, the ultrasound imaging component includes an imaging host and a cable for connecting the imaging host to a transparent PMN-PT ultrasound array transducer; and ultrasound imaging and photoacoustic imaging can be synchronized. Of course, since optical imaging does not occupy the ultrasound array probe, optical imaging, ultrasound imaging and photoacoustic imaging can be synchronized. Since both ultrasound imaging and photoacoustic imaging require the use of an ultrasound array to receive signals, the corresponding imaging timing needs to be controlled, and the purpose of rapid reality can also be achieved.
[0020] Due to the implementation of the above technical solution, the utility model has the following advantages compared with the prior art:
[0021] The existing PMN-PT transparent photoacoustic probe is still mainly a single-element probe, which can only perform two-dimensional or three-dimensional imaging through mechanical scanning and other methods, and has low efficiency. At the same time, transparent photoacoustic array probes are mainly used for photoacoustic or integrated ultrasonic imaging, and there is no integrated optical multi-modal composite probe and other deficiencies. The utility model cleverly solves the various deficiencies of the existing structure through the overall design of the structure of the transparent PMN-PT ultrasonic array transducer. After adopting the transparent PMN-PT ultrasonic array transducer, when performing ultrasonic imaging, it is only necessary to stimulate the PMN-PT ultrasonic array probe separately, and perform conventional B-mode or C-mode imaging on the received ultrasonic echo; when performing photoacoustic imaging, it is necessary to turn on the photoacoustic excitation laser, use the laser pulse trigger or the host to transmit the trigger signal to control the emission timing of the laser, and then use the PMN-PT ultrasonic The acoustic array probe receives the photoacoustic signal generated by the target and performs photoacoustic imaging; when performing optical imaging, the illumination light source is turned on to receive the CMOS transmission signal and perform optical imaging. In this way, on the one hand, the PMN-PT ultrasonic array transducer of the utility model transmits and receives ultrasonic waves in the ultrasonic imaging mode, receives the photoacoustic signal generated by the target in the photoacoustic imaging mode, and is a transparent protective window in the optical imaging mode, that is, optical imaging does not occupy the ultrasonic array probe, so it can make full use of the advantages of the light field and the ultrasonic probe, and is compatible with ultrasonic, optical and photoacoustic imaging, that is, it can form three multimodal composite probes of optical, ultrasonic and photoacoustic, and can operate synchronously, which is highly practical; on the other hand, it increases the application scenarios of the PMN-PT ultrasonic array probe, provides high-quality imaging information for related research and clinical practice, and expands the application field of transparent photoacoustic probes, which is highly practical. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 Schematic diagram of the structure of the transparent PMN-PT ultrasonic array transducer of Example 1;
[0023] Figure 2 This is a schematic diagram of the structure of the photoacoustic imaging probe of Example 2;
[0024] Figure 3 for Figure 2 Schematic diagram of the principle of the optical fiber projection unit;
[0025] Among them: 1. Transparent PMN-PT single crystal;
[0026] 2. Transparent backing layer;
[0027] 3. Transparent matching layer;
[0028] 4. Transparent conductive film;
[0029] 5. Parylene film;
[0030] A. Shell; B. Transducer; C. Photoacoustic system; c1. Ultrasonic imaging component; c10. Cable (cable); c2. Photoacoustic imaging component; c20. Photoacoustic optical fiber; c21. Optical fiber projection unit; 210. Beam expander; 211. Confocal convex lens; c3. Optical imaging component; c30. Imaging optical fiber; c31. Dichroic mirror (DM dichroic mirror); c32. CMOS sensor. DETAILED DESCRIPTION
[0031] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the utility model is described in detail below in conjunction with the accompanying drawings and specific embodiments. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.
[0032] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.
[0033] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.
[0034] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0035] In the utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.
[0036] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.
[0037] like Figure 1 As shown, the transparent PMN-PT ultrasonic array transducer of this embodiment includes a transparent PMN-PT single crystal 1, a transparent backing layer 2, a transparent matching layer 3, and a transparent conductive film 4.
[0038] Specifically, the transparent PMN-PT single crystal 1 is a multi-element linear array (or a phased array), and the number of array elements of the array transducer is ≥8, and the center frequency is ≥0.5MHz. The transparent conductive film is indium tin oxide, aluminum-doped zinc oxide, fluorine-doped tin oxide or antimony-doped tin oxide. In short, the upper and lower surfaces are sputtered with transparent conductive films as electrodes, such as indium tin oxide (ITO, In2O3: Sn), aluminum-doped zinc oxide (AZO, ZnO: Al), fluorine-doped tin oxide (FTO, SnO2: F), antimony-doped tin oxide (ATO, Sn2O: Sb), etc. The transparent backing layer is transparent tempered glass. In short, the surface where the transparent backing layer is connected to the transparent PMN-PT single crystal uses processes such as photolithography and sputtering to form a transparent conductive circuit distributed in an equally spaced array, and a pad is formed at the end for cable welding or connector connection to the cable, and is connected to the system host through the cable. The transparent matching layer is a polymer epoxy or acrylic plastic, and the thickness of the transparent matching layer is less than or equal to 1 / 4 of the thickness of the working frequency wavelength of the probe. In short, a transparent conductive film layer is also coated on the side connected to the transparent PMN-PT as an electrode, and the thickness of the matching layer is about 1 / 4 of the thickness of the working frequency wavelength of the probe.
[0039] In some specific embodiments, a transparent Parylene film 5 is formed on the surface of the transparent matching layer 3. The Parylene film 5 (which can be purchased directly from the market and is a conventional product) is mainly used to improve the acoustic matching coupling effect.
[0040] Specifically, when making the above-mentioned transducer array, the transparent backing transparent conductive circuit part and the transparent PMN-PT are first tightly bonded with transparent epoxy resin, and then a cutting machine is used to cut the transducer array according to the set size to form an array structure, and then a transparent matching layer is bonded to the upper surface of the PMN-PT with transparent epoxy resin, and the conductive layer is used to connect the cut PMN-PT arrays to form a common ground connection, and connected to the common ground cable at the edge.
[0041] Example 2
[0042] like Figure 2 As shown, the photoacoustic imaging probe involved in this embodiment includes a shell A, a transducer B, and a photoacoustic system C, wherein the transducer A is the transparent PMN-PT ultrasonic array transducer in Example 1, and the photoacoustic system C includes an ultrasonic imaging component c1, a photoacoustic imaging component c2, and an optical imaging component c2, wherein in the ultrasonic imaging mode, the transparent PMN-PT ultrasonic array transducer is used to transmit and receive ultrasonic waves; in the photoacoustic imaging mode, the transparent PMN-PT ultrasonic array transducer can receive the photoacoustic signal generated by the target; in the optical imaging mode, the transparent PMN-PT ultrasonic array transducer is a transparent protective window.
[0043] Combination Figure 3 As shown, the photoacoustic imaging component c2 includes a photoacoustic optical fiber c20 and a fiber optic projection unit c21. The fiber optic projection unit c21 includes a beam expander 210 and a confocal convex lens 211. The laser is guided by the optical fiber and then expanded and collimated before being irradiated to a transparent PMN-PT ultrasonic array transducer. In short, the laser is guided by the optical fiber and irradiated to a double concave lens for beam expansion, and then collimated by a confocal convex lens, and then vertically irradiated to a target through a transparent array transducer, providing uniform and stable laser irradiation for photoacoustic imaging. In some specific embodiments, the end of the photoacoustic optical fiber is connected to a short pulse laser for photoacoustic imaging, and mainly transmits near-infrared short pulse lasers required for photoacoustic imaging, such as Nd:YAG1064nm, near-infrared pulse lasers with adjustable wavelengths of OPO lasers, etc.
[0044] The optical imaging component c3 includes an imaging optical fiber c30, a dichroic mirror c31, and a CMOS sensor c32. After the light beam passes through the dichroic mirror c31 and the transparent PMN-PT ultrasonic array transducer, the CMOS sensor c32 transmits a signal to perform optical imaging. Specifically, the dichroic mirror c31 is a DM dichroic mirror, which is located in the middle of the probe. When the laser is incident at 45 degrees or at a large angle, the light path direction of different spectra is changed according to the different spectra of the incident light source. In the present application, when the pulsed laser used for photoacoustic imaging is irradiated on the DM, since its wavelength is greater than 800nm, the laser completely passes through the DM without reflection, and when the white light (380-750nm) for optical imaging is irradiated on the DM, since its wavelength is less than 800nm, the light irradiated on the DM is totally reflected and all irradiated on the target, and the light reflected back by the target is reflected by the DM mirror and captured by the CMOS. At the same time, the imaging optical fiber mainly transmits the continuous visible light required for optical imaging for optical imaging, such as white light excited by light sources such as LEDs and xenon lamps.
[0045] The ultrasonic imaging component c1 includes an imaging host (not shown in the figure) and a cable c10 for connecting the imaging host to the transparent PMN-PT ultrasonic array transducer; and ultrasonic imaging and photoacoustic imaging can be synchronized. Of course, since optical imaging does not occupy the ultrasonic array probe, optical imaging, ultrasonic imaging and photoacoustic imaging can be synchronized. Since both ultrasonic imaging and photoacoustic imaging require the use of an ultrasonic array to receive signals, the corresponding imaging timing needs to be controlled, which can also achieve the purpose of rapid reality.
[0046] In summary, after adopting the transparent PMN-PT ultrasonic array transducer, when performing ultrasonic imaging, it is only necessary to stimulate the PMN-PT ultrasonic array probe alone, and perform conventional B-mode or C-mode imaging on the received ultrasonic echo; when performing photoacoustic imaging, it is necessary to turn on the photoacoustic excitation laser, use the laser pulse trigger or the host to transmit the trigger signal to control the emission timing of the laser, and then use the PMN-PT ultrasonic array probe to receive the photoacoustic signal generated by the target to perform photoacoustic imaging; when performing optical imaging, turn on the illumination light source, receive the CMOS transmission signal, and perform optical imaging. In this way, on the one hand, the utility model transmits and receives the PMN-PT ultrasonic array transducer in the ultrasonic imaging mode. Ultrasonic waves receive the photoacoustic signals generated by the target in the photoacoustic imaging mode and are a transparent protective window in the optical imaging mode, that is, optical imaging does not occupy the ultrasonic array probe, so it can make full use of the advantages of the light field and ultrasonic probe, and is compatible with ultrasonic, optical and photoacoustic imaging, that is, it can form three multimodal composite probes of optical, ultrasonic and photoacoustic, and can operate synchronously, which is highly practical; on the other hand, it increases the application scenarios of the PMN-PT ultrasonic array probe, provides high-quality imaging information for related research and clinical practice, and expands the application field of transparent photoacoustic probes, which is highly practical; on the third aspect, it can effectively solve the shortcomings of the existing photoacoustic probe structure and imaging, the equipment has a simple structure and rich functions, and meets the needs of high-performance multimodal imaging.
[0047] The above detailed description of the utility model is intended to enable people familiar with the technology in this field to understand the content of the utility model and implement it. It is not intended to limit the protection scope of the utility model. All equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.
Claims
1. A transparent PMN-PT ultrasonic array transducer, comprising a transparent PMN-PT single crystal, characterized in that: The transparent PMN-PT single crystal is a multi-element linear array or phased array, and the transducer also includes a transparent backing layer and a transparent matching layer located on the surfaces of both ends of the transparent PMN-PT single crystal; and a transparent conductive film located between the transparent backing layer and the transparent PMN-PT single crystal, and between the transparent PMN-PT single crystal and the transparent matching layer, wherein the transparent conductive film serves as an electrode and forms a transparent conductive circuit with the transparent PMN-PT single crystal, and forms a pad at the end for cable welding or connector connection with the cable.
2. The transparent PMN-PT ultrasonic array transducer according to claim 1, characterized in that: The transparent backing layer is transparent tempered glass.
3. The transparent PMN-PT ultrasonic array transducer according to claim 1, characterized in that: The transparent matching layer is made of high molecular weight epoxy or acrylic plastic.
4. The transparent PMN-PT ultrasonic array transducer according to claim 1, characterized in that: The thickness of the transparent matching layer is less than or equal to 1 / 4 of the wavelength of the working frequency of the probe.
5. The transparent PMN-PT ultrasonic array transducer according to claim 1, characterized in that: The number of array elements is ≥8, and the center frequency is ≥0.5MHz.
6. The transparent PMN-PT ultrasonic array transducer according to claim 1, characterized in that: A layer of transparent Parylene film is also formed on the surface of the transparent matching layer.
7. A photoacoustic imaging probe, comprising a housing, a transducer, and a photoacoustic system, characterized in that: The transducer is the transparent PMN-PT ultrasonic array transducer as described in any one of claims 1 to 6, and the photoacoustic system includes an ultrasonic imaging component, a photoacoustic imaging component, and an optical imaging component, wherein in the ultrasonic imaging mode, the transparent PMN-PT ultrasonic array transducer is used to transmit and receive ultrasonic waves; in the photoacoustic imaging mode, the transparent PMN-PT ultrasonic array transducer can receive the photoacoustic signal generated by the target; in the optical imaging mode, the transparent PMN-PT ultrasonic array transducer is a transparent protective window.
8. The photoacoustic imaging probe according to claim 7, characterized in that: The photoacoustic imaging component includes a photoacoustic optical fiber and a fiber optic projection unit. The fiber optic projection unit includes a beam expander and a confocal convex lens. The laser is guided by the optical fiber and then expanded and collimated and then irradiated to the transparent PMN-PT ultrasonic array transducer.
9. The photoacoustic imaging probe according to claim 7, characterized in that: The optical imaging component includes an imaging optical fiber, a dichroic mirror, and a CMOS sensor. After the light beam passes through the dichroic mirror and the transparent PMN-PT ultrasonic array transducer, the CMOS sensor transmits a signal to perform optical imaging.
10. The photoacoustic imaging probe according to claim 7, characterized in that: The ultrasonic imaging component includes an imaging host and a cable for connecting the imaging host with the transparent PMN-PT ultrasonic array transducer; and optical imaging, ultrasonic imaging and photoacoustic imaging can be synchronized.