phased array method of ultrasound focusing piezo

Ultrasound focusing piezo ceramic is not only important ultrasound surgery, but also ultrasound diagnostics. people always want to see smaller, more subtle organizational structures, such as the internal organization of the internal organs of the human body, eyes and skin, etc., not only to increase the working frequency, but also to require sound beam focusing.The focus of the sound beam is the same as that of the light beam, except for the following seven methods (l): lens, and the following physical lens, there is a geometric lens, which is similar to an optical lens, and is made into a lens by using different sound speeds in the different media. There are two types of lenses: one is a liquid lens, but the shape is difficult to control, and the other is a solid lens with a fixed shape, but there are two kinds of waves in the solid, so the image quality is not good; (2): piezo spheres transducer straight is engaged as a concave array; (3): assisted focusing with a mirror: (4): physical lens is a Fresnel strip, appropriate.The frequency sound waves can be focused at a certain distance by distributing the strips according to the law of Chi.

The method of piezoelectric disc transducer these beams is fixed, and the ultrasound treatment often needs to adjust the focus.The zoom and focus directions are more important in changing the focus position in the ultrasound imaging. And use the above these methods can only change the focus position mechanically, but the mechanical adjustment is very inconvenient and the speed is very slow.This limits its application. So the phased array method was proposed, which uses electronic technology to adjust the focus position and the direction of focus.it is dynamic focus adjustment now. Its basic idea is to adjust the phase of the transmitted signals of each array piezoelectric vibration sensor so that each array element arrives.The focus of the sound beam has the same phase, which is achieved. The assembly (very early for phase array for scanning imaging systems,The development and maturity of the surgery has also gone through a process.

?A continuous linear array consists of a number of individual transducers arranged in the row, each array element is emitting separately. it forms a two-dimensional image.

For the sake of simplicity, only five array elements are drawn. First, the uppermost array elements are transmitter is accepted, all participating in the transmission and acceptance, and finally form a rectangular scanning plane,The number of lines and the number of array piezoelectric transducer for underwater comunications are equal, it has studied the system, the system size is: 30-124 array elements, the total length is 5 cm. The disadvantage of applying this array scan is that the width of the imaging field is equal to the length of the linear array, which limits the use of the system, such as the diagnosis of heart disease, which is limited by the spacing of the ribs.