CN100399596C - Phased Array Probes for Scanning Imaging Setups - Google Patents

本发明公开了一种用于扫描成像装置的相控阵探头。该探头包括由换能器单元组成的阵列，换能器单元为在工作时发射横波的横波换能器；换能器单元呈长方体，由压电块和非压电块组成，压电块的偏振方向沿换能器单元的长度方向；所述压电块和非压电块在换能器单元的宽度方向上交错放置；各换能器单元的上下表面分别覆盖有上电极和下电极。本发明的相控阵探头可以直接产生纯横波，避免了波型转换带来的能量损失或其它干扰，避免了固体中声波波型转换带来的影响；使用该探头不仅可以利用电子相控技术实现对固体材料的垂直纯横波声束电子扫描，还可对粘接界面的液体夹层及零间隙脱粘进行检测。

The invention discloses a phased array probe used for a scanning imaging device. The probe includes an array composed of transducer units. The transducer unit is a shear wave transducer that emits shear waves during operation; the transducer unit is in the shape of a cuboid and consists of piezoelectric blocks and non-piezoelectric blocks. The polarization direction is along the length direction of the transducer unit; the piezoelectric blocks and non-piezoelectric blocks are alternately placed in the width direction of the transducer unit; the upper and lower surfaces of each transducer unit are covered with upper electrodes and lower electrodes respectively. The phased array probe of the present invention can directly generate pure shear waves, avoiding energy loss or other interference caused by wave mode conversion, and avoiding the influence of acoustic wave mode conversion in solids; using the probe can not only use electronic phase control technology Realize the electronic scanning of vertical pure transverse wave acoustic beam on solid materials, and also detect the liquid interlayer and zero-gap debonding at the bonding interface.

用于扫描成像装置的相控阵探头 Phased Array Probes for Scanning Imaging Setups

技术领域 technical field

本发明涉及一种用于扫描成像装置的探头，具体地说，涉及一种用于扫描成像装置的相控阵探头。The present invention relates to a probe for scanning imaging device, in particular to a phased array probe for scanning imaging device.

背景技术 Background technique

传统的相控阵成像技术利用超声纵波探头组成探头阵列对检测对象进行电子扫描成像。由于在固体中存在波型转换，传统的纵波相控阵技术在用于固体介质的检测时会遇到额外的干扰。另外，在粘接界面的液体夹层及零间隙脱粘的检测中，采用超声纵波无法检测。The traditional phased array imaging technology uses ultrasonic longitudinal wave probes to form a probe array to electronically scan and image the detection object. Due to the existence of wave mode conversion in solids, the traditional longitudinal wave phased array technology will encounter additional interference when used in the detection of solid media. In addition, in the detection of liquid interlayer and zero-gap debonding at the bonding interface, ultrasonic longitudinal waves cannot be used to detect.

相对于纵波，横波探测有其独特的优势。从传播理论可知，对于各向异性等复杂介质材料纯横波的散射、反射特性比较单纯，采用横波检测有纵波无法达到的效果。在相同的频率条件下，横波波长比纵波波长几乎要小一倍，因此对同样大小的缺陷，横波的反射能量相对也要大的多。同时，在对粘接界面缺陷中液体夹层的检测中，横波的灵敏度也远比纵波高。Compared with longitudinal wave, shear wave detection has its unique advantages. It can be seen from the propagation theory that the scattering and reflection characteristics of pure shear waves in complex dielectric materials such as anisotropy are relatively simple, and the detection of shear waves has the effect that longitudinal waves cannot achieve. Under the condition of the same frequency, the wavelength of the shear wave is almost twice as small as that of the longitudinal wave, so the reflected energy of the shear wave is relatively much larger for defects of the same size. At the same time, in the detection of liquid interlayers in the bonding interface defects, the sensitivity of shear waves is much higher than that of longitudinal waves.

虽然在焊缝的超声检测中，有时使用横波阵列探头([1].Roy，O.Mahaut，S.Casula，O.Development of a smart flexible transducer to inspect component ofcomplex geometry：modeling and experiment，AIP Conference Proceedingsno.615A：908-14，2002)，但是，组成探头阵列的阵元直接辐射纵波，然后倾斜入射在耦合界面上，利用波型转换在检测介质中产生横波。这种利用波型转换技术，产生横波的效率受到影响，并常伴有纵波或表面波使其检测受到影响。也有使用电磁声技术产生SH横波进行金属板测厚^[2]，但设备相对比较复杂，检测条件要求高，且只适用于铁磁性介质，目前也还没有实际可以用于小当量缺陷检测的产品。使用其他方法也能够产生横波([2].Murray，P.R.Dewhurst，R.J.Laser/EMAT measurement systems for ultrasound B-scan imaging，Sensors and theirApplications XI.Proceedings of the Eleventh Conference on Sensors and theirApplications：169-74，2001；[3].Every，A.G.Sachse，W.Imaging oflaser-generatedultrasonic waves in silicon，Physical Review B(Condensed Matter)，vol.44，no.13：6689-99，1Oct.1991 Language：English；[4].汪承灏，乔东海，固体表面菲涅尔阵列产生的声束聚焦的研究，声学学报，Vol.24，No.4，1999，pp351-356)，但也常伴随纵波，不能够得到模式纯净的横波辐射声场。Although in ultrasonic testing of welds, shear wave array probes are sometimes used ([1].Roy, O.Mahaut, S.Casula, O.Development of a smart flexible transducer to inspect component of complex geometry: modeling and experiment, AIP Conference Proceedingsno .615A:908-14, 2002), however, the array elements that make up the probe array directly radiate longitudinal waves, and then obliquely incident on the coupling interface, using wave mode conversion to generate shear waves in the detection medium. This use of wave mode conversion technology affects the efficiency of generating shear waves, and is often accompanied by longitudinal waves or surface waves to affect the detection. There is also the use of electromagnetic acoustic technology to generate SH transverse waves to measure the thickness of metal plates ^[2] , but the equipment is relatively complicated, the detection conditions are high, and it is only suitable for ferromagnetic media. At present, there is no product that can actually be used for small equivalent defect detection. . Transverse waves can also be generated using other methods ([2]. Murray, PRDewhurst, RJLaser/EMAT measurement systems for ultrasound B-scan imaging, Sensors and their Applications XI. Proceedings of the Eleventh Conference on Sensors and their Applications: 169-74, 2001; [ 3]. Every, AGSachse, W. Imaging of laser-generated ultrasonic waves in silicon, Physical Review B (Condensed Matter), vol.44, no.13: 6689-99, 1Oct.1991 Language: English; [4]. Wang Chenghao, Qiao Donghai, Research on the Focusing of Acoustic Beams Produced by Fresnel Arrays on Solid Surfaces, Acta Acoustica Sinica, Vol.24, No.4, 1999, pp351-356), but it is often accompanied by longitudinal waves, and it is impossible to obtain a pure shear wave radiation sound field .

发明内容 Contents of the invention

本发明的目的是为了克服现有技术中扫描成像装置的探头不能直接发射横波，因而效率低并限制其应用等缺点，通过设计可直接产生横波的换能器单元，从而提供了一种用于扫描成像装置的相控阵探头。The purpose of the present invention is to overcome the shortcomings of the scanning imaging device in the prior art that the probe cannot directly emit shear waves, thus having low efficiency and limiting its application, and by designing a transducer unit that can directly generate shear waves, thereby providing a kind for Phased array probe for scanning imaging setup.

本发明的技术方案为：Technical scheme of the present invention is:

一种用于扫描成像装置的相控阵探头，该探头包括由换能器单元2组成的阵列，所述换能器单元2为在工作时发射横波的横波换能器；所述换能器单元2呈长方体，由压电块3和非压电块4组成，压电块3的偏振方向沿换能器单元2的长度方向；所述压电块3和非压电块4在换能器单元2的宽度方向上交错放置；各换能器单元2的上下表面分别覆盖有上电极5和下电极6。A kind of phased array probe for scanning imaging device, this probe comprises the array that is made up of transducer unit 2, and described transducer unit 2 is the transverse wave transducer that emits transverse wave when working; The transducer The unit 2 is a cuboid and is composed of a piezoelectric block 3 and a non-piezoelectric block 4. The polarization direction of the piezoelectric block 3 is along the length direction of the transducer unit 2; The transducer units 2 are placed alternately in the width direction; the upper and lower surfaces of each transducer unit 2 are covered with upper electrodes 5 and lower electrodes 6 respectively.

所述探头还包括支撑结构体1，所述换能器单元2嵌在支撑结构体1内。所述换能器单元2的宽度小于等于λ/2，其厚度小于等于λ/2，其中λ等于所需发射声波的波长。所述阵列包括两个或两个以上换能器单元2，并且换能器单元2沿其宽度方向间隔放置。所述阵列为线性阵列或环形阵列。相邻换能器单元2之间的距离大于等于隔离换能器单元间耦合振动需要的最小距离。该探头还包括设置在所述换能器单元2声辐射面上的保护膜，设置在所述换能器单元2背面上的背衬。The probe also includes a supporting structure 1 , and the transducer unit 2 is embedded in the supporting structure 1 . The width of the transducer unit 2 is less than or equal to λ/2, and its thickness is less than or equal to λ/2, where λ is equal to the wavelength of the sound wave to be emitted. The array includes two or more transducer units 2, and the transducer units 2 are placed at intervals along the width direction thereof. The array is a linear array or a circular array. The distance between adjacent transducer units 2 is greater than or equal to the minimum distance required to isolate the coupled vibration between transducer units. The probe also includes a protective film arranged on the sound radiation surface of the transducer unit 2 and a backing arranged on the back of the transducer unit 2 .

在实际使用时，可将本发明提供的相控阵探头与现有技术的扫描成像装置的发射/接收电路部分通过多束高频屏蔽电缆连接，从而构成完整的相控阵扫描成像装置。In actual use, the phased array probe provided by the present invention can be connected to the transmitting/receiving circuit part of the scanning imaging device in the prior art through multiple bundles of high-frequency shielded cables, thereby forming a complete phased array scanning imaging device.

本发明提供的用于扫描成像装置的相控阵探头的优点在于：该探头可以直接产生纯横波，避免了波型转换带来的能量损失或其它干扰，避免了固体中声波波型转换带来的影响；使用该探头，不仅可以利用电子相控技术实现对固体材料的垂直纯横波声束电子扫描，还可对粘接界面的液体夹层及零间隙脱粘进行检测。The advantages of the phased array probe used for scanning imaging devices provided by the present invention are: the probe can directly generate pure shear waves, avoiding energy loss or other interference caused by wave mode conversion, and avoiding the problems caused by the sound wave mode conversion in solids. Using this probe, not only can use the electronic phase control technology to realize the electronic scanning of the vertical pure shear wave acoustic beam on the solid material, but also detect the liquid interlayer and zero-gap debonding at the bonding interface.

本发明提供的用于扫描成像装置的相控阵探头，可用于固体材料的超声无损检测，其中包括粘接界面的质量评价。The phased array probe used in the scanning imaging device provided by the invention can be used in the ultrasonic non-destructive testing of solid materials, including the quality evaluation of the bonding interface.

附图说明 Description of drawings

图1是本发明线形相控阵探头的结构示意图；Fig. 1 is the structural representation of linear phased array probe of the present invention;

图2是图1中换能器单元的结构示意图；Fig. 2 is a schematic structural view of the transducer unit in Fig. 1;

图3是本发明环形相控阵探头的结构示意图；Fig. 3 is the structural representation of annular phased array probe of the present invention;

图4是采用本发明相控阵探头的扫描成像装置示意图；4 is a schematic diagram of a scanning imaging device using a phased array probe of the present invention;

图面说明：Graphic description:

支撑结构体1    换能器单元2    压电块3Support structure 1 Transducer unit 2 Piezoelectric block 3

非压电块4      上电极5        下电极6Non-piezoelectric block 4 upper electrode 5 lower electrode 6

具体实施方式 Detailed ways

下面结合附图与具体实施方式对本发明作进一步详细描述：Below in conjunction with accompanying drawing and specific embodiment the present invention is described in further detail:

如图1所示，8个换能器单元2沿其宽度方向平行间隔组成线性阵列，相邻换能器单元2之间间距为0.1毫米；此阵列嵌在支撑结构体1内，支撑结构体为环氧树脂材料。As shown in Figure 1, 8 transducer units 2 are spaced in parallel along the width direction to form a linear array, and the distance between adjacent transducer units 2 is 0.1 mm; this array is embedded in the support structure 1, and the support structure For epoxy resin material.

换能器单元2的结构如图2所示，它基本上呈长方体，其宽度为0.8毫米，厚度为1.1毫米，长度为10毫米，该换能器单元2发射声波的波长为3毫米(对应于检测体为金属钢的情形)，在其宽度方向方向上，交错放置有长条形的3个压电块3和4个非压电块4；压电块3的偏振方向沿换能器单元2的长度方向；压电块3使用压电材料，可以为锆钛酸铅压电陶瓷，如PZT-5A和PZT-4，也可用其它系列的压电材料如钛酸钡、偏铌酸铅、铌酸钾钠、钛酸铅压电陶瓷或石英晶体。非压电块的材料为环氧树脂如E-51，或其它双酚A型环氧树脂如E-44或E-55。换能器单元2的上下表面分别覆盖有上电极5和下电极6。The structure of transducer unit 2 is as shown in Figure 2, and it is cuboid substantially, and its width is 0.8 millimeter, and thickness is 1.1 millimeter, and length is 10 millimeters, and the wavelength of this transducer unit 2 emission sound waves is 3 millimeters (corresponding to In the case that the detection body is metal steel), three strip-shaped piezoelectric blocks 3 and four non-piezoelectric blocks 4 are staggered in the direction of its width direction; the polarization direction of the piezoelectric blocks 3 is along the direction of the transducer The length direction of unit 2; the piezoelectric block 3 uses piezoelectric materials, which can be lead zirconate titanate piezoelectric ceramics, such as PZT-5A and PZT-4, and other series of piezoelectric materials such as barium titanate and metaniobic acid can also be used Lead, potassium sodium niobate, lead titanate piezoelectric ceramic or quartz crystal. The material of the non-piezoelectric block is epoxy such as E-51, or other bisphenol A type epoxy such as E-44 or E-55. The upper and lower surfaces of the transducer unit 2 are covered with an upper electrode 5 and a lower electrode 6, respectively.

换能器单元2的声辐射面上设有材料为环氧树脂加280目金刚砂的保护膜(未示出)，其中，金刚砂也可用硅酸盐类微粉或刚玉类微粉等绝缘体微粉代替。换能器单元2的背面设有环氧树脂加金属粉末的背衬(未示出)，例如加钨粉。The sound radiation surface of the transducer unit 2 is provided with a protective film (not shown) made of epoxy resin plus 280 mesh corundum, wherein the corundum can also be replaced by insulator micropowder such as silicate micropowder or corundum micropowder. The back of the transducer unit 2 is provided with a backing (not shown) of epoxy plus metal powder, for example plus tungsten powder.

还可将换能器单元2排列成环形阵列的形式，如图3所示。The transducer units 2 can also be arranged in a circular array, as shown in FIG. 3 .

应用本发明的相控阵探头的扫描成像装置如图4所示，该装置的电子部分可采用现有的扫描成像装置中的电子部分。该装置包括相控阵探头、整机控制单元、发射/接收部分、A/D采样与合成处理部分、结果显示与输出部分，其中本发明的相控阵探头各换能器单元的电极与发射/接收电路部分通过多束高频屏蔽电缆连接。该装置为全数字化相控阵成像设备，通过整机控制单元产生发射声束偏转和聚焦所需要的延迟触发脉冲，控制发射电路形成高压激励脉冲，激励相控阵各阵元发射纯横波声波。本发明中换能器单元产生的纯横波偏振方向与传播方向、单元的排列方向垂直。产生的横波通过扫描阵与检测体表面之间的横波耦合剂(如粘稠的蜂蜜)进入检测体。发射的声束由相控阵发射/接收部分中的发射单元合成偏转聚焦。当遇到声阻抗不连续的区域如缺陷界面、工件底面，声波发生反射，反射信号与反射面/体的大小、形状、性质等因素有关，对于粘接界面。如果存在弱粘接区域或粘接界面存在缺陷，将产生与完全粘好界面不同的反射信号。由于本发明使用纯横波技术，因此反射信号的幅度或相位反映了粘接界面的受切变力时的位移或者形变特性。当粘接界面属于液体夹层类缺陷时，界面两侧的纵向位移和应力连续，而切向应力不连续，因此利用横波可以得到很强的反射信号，但纵波的传播不受影响。当夹层的液体属于理想液体时，横波的反射系数等于1。反射信号传播到换能器阵列后，由于晶片的压电效应而在晶片上产生相应的电压信号，该电压信号送到发射/接收部分中的接收单元。经放大、预处理、A/D单元采集输入计算机后，通过信号处理的方法完成数字声束合成、动态聚焦等后续处理，实现检测回波的A、B、C扫描成像，检测结果可在显示终端上显示，也可打印输出。The scanning imaging device using the phased array probe of the present invention is shown in Fig. 4, and the electronic part of the device can adopt the electronic part of the existing scanning imaging device. The device includes a phased array probe, a complete machine control unit, a transmitting/receiving part, an A/D sampling and synthesis processing part, a result display and an output part, wherein the electrodes of each transducer unit of the phased array probe of the present invention and the transmitting The /receiving circuit part is connected by multiple bundles of high-frequency shielded cables. The device is an all-digital phased array imaging device. The control unit of the whole machine generates the delayed trigger pulse required for the deflection and focusing of the transmitted acoustic beam, controls the transmitting circuit to form a high-voltage excitation pulse, and excites each element of the phased array to emit pure transverse wave sound waves. In the present invention, the polarization direction of the pure transverse wave generated by the transducer unit is perpendicular to the propagation direction and the arrangement direction of the units. The generated shear wave enters the detection body through the shear wave coupling agent (such as sticky honey) between the scanning array and the surface of the detection body. The emitted sound beam is synthesized, deflected and focused by the transmitting unit in the phased array transmitting/receiving part. When encountering a region with discontinuous acoustic impedance, such as a defect interface or the bottom surface of a workpiece, the sound wave is reflected, and the reflected signal is related to factors such as the size, shape, and nature of the reflecting surface/body, for the bonding interface. If there are weakly bonded areas or defects in the bonded interface, it will produce a different reflection signal than a fully bonded interface. Since the present invention uses pure shear wave technology, the amplitude or phase of the reflected signal reflects the displacement or deformation characteristics of the bonding interface when subjected to shear force. When the bonding interface belongs to liquid interlayer defects, the longitudinal displacement and stress on both sides of the interface are continuous, but the tangential stress is discontinuous. Therefore, a strong reflection signal can be obtained by using the shear wave, but the propagation of the longitudinal wave is not affected. When the liquid in the interlayer is an ideal liquid, the reflection coefficient of the shear wave is equal to 1. After the reflected signal propagates to the transducer array, a corresponding voltage signal is generated on the wafer due to the piezoelectric effect of the wafer, and the voltage signal is sent to the receiving unit in the transmitting/receiving part. After amplification, preprocessing, and A/D unit acquisition and input into the computer, digital sound beam synthesis, dynamic focusing and other follow-up processing are completed through signal processing methods, and A, B, and C scanning imaging of detected echoes are realized. The detection results can be displayed on the display It can be displayed on the terminal or printed out.

在相控阵成像检测的过程中应保持耦合状态的稳定，以获得比较一致的检测信号。In the process of phased array imaging detection, the coupling state should be kept stable to obtain relatively consistent detection signals.