The invention provides a transcranial Doppler plane annular phased array probe, which comprises a piezoelectric vibrator, a metal shielding casing, an electronic tuning circuit, a coaxial cable, a case, a back lining, a matching layer and an acoustic lens, wherein the piezoelectric vibrator comprises more than one array element ring in annular distribution to form concentric circles, each array element ring adopts independent lead wire control, the areas of all array elements are identical, in addition, the path differences of all array elements are identical, each independent array element is excited by adopting specific time delay, and the dynamic focusing in the spreading direction of ultrasonic beams can be achieved. The plane annular phased array is utilized, each array element is respectively subjected to time delay during the emitting or receiving, and the emitting focusing or the receiving focusing is realized, so focal points can be continuously adjusted, the ultrasonic beams can be effectively and controllably narrowed, the depth of field is long, the transcranial Doppler plane annular phased array probe has the advantages of variable aperture, variable focal point, variable trace and the like, the lateral resolution ratio of a system can be comprehensively improved, and the signal to noise ratio is effectively improved.

Transcranial Doppler plane annular phased array probe

The invention relates to jet angle controllable ultrasonic droplet jetting additive manufacturing device and method, belonging to the field of additive manufacturing. The device is characterized in that a base is installed at the bottom; a jet tank is installed on the base; a focused ultrasonic transducer is installed in the jet tank; a base plate is fixed below wafer bearing platforms and above the jet tank; the wafer bearing platforms are installed on a Z-direction workbench; the Z-direction workbench is installed on the base; the jet tank is communicated with a liquid storage tank; a high-precision injection pump is connected with a feeding head; through focused ultrasound, liquid overcomes the surface tension and jets droplets from the liquid level; the power of four focused ultrasonic vibrators of the focused ultrasonic transducer is controlled by a computer and the focused ultrasonic vibrators interact and then change the jet angles of the droplets to jet the droplets to different positions on the base plate; a Z-axis motion platform cooperates with different jet angles to complete printing of different position points on the base plate. The device and the method have the effects of improving the printing precision and ensuring the physical and chemical properties and other properties of formed parts without needing print heads, thus avoiding pollution and cleaning difficulty of liquid materials.

Jet angle controllable ultrasonic droplet jetting additive manufacturing device and method

The invention discloses a sensor structure with a periodic band gap structure. The sensor structure comprises a plurality of one-dimensional phononic crystal sector structures arranged at the same center, and a plurality of piezoelectric sensors correspondingly arranged inside the one-dimensional phononic crystal sector structures one by one, wherein an air anti-interference zone is arranged between adjacent one-dimensional phononic crystal sector structures at the same time. The invention has the advantages that the sensor structure is designed by using a periodic structure and made of acoustic super material forming an optical band gap structure, and the sensing signal is enhanced by using the local resonance effect on the special frequency band of the signal, thereby achieving the purpose of improving the sensitivity of the sensor, and making the designed sensor structure have special physical properties.

Sensor structure with periodic band gap structure

The invention provides an ultrasonic focusing method used for sonodynamic therapy. According to the invention, a 3D geometric model of a target area for sonodynamic therapy is acquired by utilizing a 2D ultrasonic phased array technology and a 3D acoustic model of the target area is constructed. A phased array focusing rule required for therapy is calculated according to a target position, a target size and the 3D acoustic model and excitation is performed on different array elements in a 2D ultrasonic phased array probe according to the phased array focusing rule. By adopting the method provided by the invention, energy can be focused to a lesion part accurately, the accuracy of sonodynamic therapy is improved and damage to normal parts can be reduced in the maximal level. Since the focusing method is adopted, the acoustic energy input efficiency is improved. Besides, the target position in the invention is determined through the focusing rule. The acoustic energy can be focused to the lesion part without movement of the probe during the therapy process, so that the operation is convenient and the efficiency is high. The method provided by the invention solves problems of poor acoustic energy input efficiency and poor treatment accuracy in traditional sonodynamic therapy.

Ultrasonic focusing method used for sonodynamic therapy

The invention relates to a capacitance type annular dynamic focusing air coupling ultrasonic transducer, which comprises a metal substrate, a plated electrode polymer film, and a phased array time-delay excitation circuit The upper surface of the metal substrate is provided with a coarse cavity The coarse cavity is covered by the polymer film, and the upper surface of the polymer film is provided with a plated electrode The metal substrate is composed of a plurality of annular array elements The annular array elements are connected to one end of the phased array time-delay excitation circuit The other end of the phased array time-delay excitation circuit is connected to one end of a bias voltage circuit, and is taken as an excitation source by being connected to the transducer metal substrate electrode The annular array elements form an annular focusing phased array, which is used to emit sound waves The bias voltage circuit is used to tightly attaching the polymer film onto thesurface of the metal substrate so as to form a cavity resonant cavity through an electrostatic effect The provided ultrasonic transducer has the advantages of simple structure and low processing andmanufacturing cost, can form array elements with a small size, can realize dynamic focusing and air coupling dynamic nondestructive detection, and improves the detection speed and resolution

Capacitance type annular dynamic focusing air coupling ultrasonic transducer

The invention discloses a two-dimensional annular phased array ultrasonic transducer structure for three-dimensional ultrasonic imaging. The transducer structurally comprises more than one array element ring which is annularly distributed in a concentric circle way, and each array element ring comprises more than two array elements, and the area of each array element is the same. According to the two-dimensional annular phased array ultrasonic transducer structure, the defect of signal to noise ratio caused by high technical process difficulty and small array element size of a two-dimensional area array transducer can be overcome, and the limit that a one-dimensional array and a phased array are in geometric focusing fixing, and a wave beam cannot be effectively narrowed can be overcome, so that the lateral resolution can be comprehensively improved, the signal to noise ratio can be effectively increased, and real-time three-dimensional ultrasonic imaging can be realized by electronic phased scanning.

Two-dimensional annular phased array ultrasonic transducer structure

Most high frequency (> 15 MHz) medical ultrasound systems are based on single element transducers mechanically scanned. These systems can provide images with excellent resolution. However, single element transducers are often limited by the fixed focal point and small depth of field. Annular arrays consisting of concentric rings of elements are focused electronically. These arrays are desirable to avoid the fixed focal point of the single element transducers and improve the depth of field. This paper reports the design, fabrication, and characterization of a 5-element equal-area annular array transducer. After electrical impedance matching, the average center frequency was 20 MHz and -6 dB bandwidths ranged from 34 to 42%. The ILs for the matched annuli ranged from 6.1 to 26.5 dB.

https://www.worldscientific.com/doi/pdf/10.1142/S1793545811500106

DESIGN AND FABRICATION OF A 20 MHz ANNULAR ARRAY FOR MEDICAL ULTRASOUND

In this paper, a novel 7 mm diameter, 8-elements, 10MHz electrical focusing 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT) single crystal annular array using equal area elements, has been designed and evaluated. Separation of elements was achieved using 355 nm ultraviolet laser ablation techniques. A novel electrical interconnection strategy for high frequency array elements was implemented. After the transducer was attached to the electric connection board and packaged, the annual array was tested in a pulse/echo arrangement, whereby the center frequency, bandwidth and two-way insertion loss were measured for each annulus. The annular array produced pulses with a centre frequency of 10 MHz and nearly 78 % bandwidth at -6dB. The average insertion loss was -27 dB at centre frequency. The improved lateral resolution and depth of field from the 50μm aluminum wire phantom image were observed, in which the axial and lateral resolutions at 12 mm depth are found to be 650 μm and 188 μm, respectively. Ultrasonic images of cattle eyes also were obtained with the 10-MHz annual array transducer. In the anterior portion of cattle eye it can be seen that the cornea and iris are well distinguishable. For the clinical ophthalmologic application, the B/D scan is not desirable because the transducer is moved in the axial direction, increasing the possibility of damaging the surface of the cornea. This eight element annular transducer is promising for ophthalmology and dermatology ultrasonic imaging and other high frequency ultrasonic diagnostics applications.

Zhenhua Hu

Papers

Two-dimensional annular phased array ultrasonic transducer structure

DESIGN AND FABRICATION OF A 20 MHz ANNULAR ARRAY FOR MEDICAL ULTRASOUND

Fabrication and performance of a 10 MHz annular array based on PMN-PT single crystal for medical imaging