SU1357833A1 - Ultrasonic piezoelectric transducer - Google Patents

Abstract

The invention relates to the field of non-destructive testing and can be used in ultrasonic flaw detection and medical diagnostics. The aim of the invention is to increase the sensitivity by increasing the efficiency of conversion of electric energy into acoustic energy when using one type of ultrasonic oscillations corresponding to the basic natural mode of oscillation of the polarized resonant element i. In an ultrasonic piezoelectric transducer, the radiation of ultrasonic oscillations occurs at the ends of a piezocke7J U fJ a (L

Description

frame rods /, on the side surfaces of which, perpendicular to the direction of polarization of the piezoelectric ceramics, excitatory electrodes 8 and 9 are deposited. In this case, the cross-sectional dimensions of the piezoceramic rods 7 are chosen to be much shorter than the ultrasonic oscillation wavelength in the piezoceramic material. Thus, in the piezoceramic rod 7, the existence of

one

The invention relates to the field of non-destructive testing and can be used in ultrasonic flaw detection and medical diagnostics.

The purpose of the invention is to increase the sensitivity by increasing the efficiency of conversion of electrical energy into acoustic energy using one type of ultrasonic oscillations, corresponding to the basic natural mode of oscillations of a polarized resonant element.

Figure 1 presents the scheme of the ultrasonic piezoelectric transducer; Fig. 2 is a diagram of a resonant piezoelectric polarized structure.

An ultrasonic piezoelectric transducer contains a resonant piezoelectric polarized structure 1 electric screen 2, a damper 3 and a matching layer 4.

The resonant piezoelectric polarized structure 1 is made in the form of a matrix of a set of elements 5 consisting of rectangular section section 7 arranged in the same plane and separated by acoustic material 6, which is polarized in the direction of size d, perpendicular to their length. Electrodes 8 and 9 are deposited on the surface of piezoceramic rods 7, perpendicular to the direction of polarization, while electrodes 8 are applied on the same orientation

only one type of ultrasonic oscillations corresponding to the basic eigenmode oscillations of the piezocher- mic rod 7 in the length direction. Thus, all the electrical excitation energy supplied to the ultrasonic piezo transducer is completely converted into the energy of ultrasonic vibrations at the operating frequency of the ultrasonic piezo transducer. 2 Il.

The oriented surfaces of the piezoceramic rods 7 are interconnected by p-ins 10 and with the electric screen 2 and form the first terminal 11

ultrasonic transducer.

The electrodes 9, deposited on oppositely oriented surfaces of piezoceramic rods 7, belonging to one element 5, are electrically combined with the help of tires 12 into groups and form the second electrical leads 13 of the ultrasonic transducer according to the number of elements 5 ,. The lateral dimensions of piezoceramic

rods 7 are selected from the conditions d aj, t: D, where d and t are the transverse dimensions of the piezoceramic rod 7 in the direction of polarization and perpendicular to it,, and / 1. - length

 -,

waves in the material of the rod 7 in the direction of polarization and perpendicular to it. For The exclusion of the mutual influence of the piezoceramic rods 7 on each other serves to divide them in an acoustically soft material.

The ultrasonic piezoelectric transducer works as follows.

When elements 5 are connected together, the first 11 and second 13 electrical leads are connected to a common excitation channel - reception (not shown). In the radiation mode, the electric excitation pulses through the excitation channel - reception arrive at the bus

to and 12 and through them to the electrodes 8 and 9 of all piezoelectric rods 7. The result is between the electrodes 8 and

9, an electric field arises that excites ultrasonic oscillations in piezoceramic rods x 7, which are transmitted through the matching layer 4 to the object under study (not shown). The frequency of the ultrasonic oscillations emitted by the ultrasonic piezo transducer is determined by the length J of the piezoceramic rods 7. In the mode, the ultrasonic vibrations received by the ultrasonic piezo transducer are transmitted to the piezoceramic rods 7 via the first 11 and second 13 electrical leads enter the electrical excitation channel where they are processed,

I

Likewise ultrasound

The piezoelectric transducer works in the case when each element 5 through the first 11 and second 13 pins is connected to an individual excitation-reception channel. Such connection of an ultrasonic piezotransducer allows one to realize a mode in which the direction of the maximum emission of ultrasonic vibrations makes a certain angle with the direction normal to the aperture of the ultrasonic piezotransducer, by creating time delays between the electrical pulses that excite the elements 5, in the same way in the reception, there is the possibility of in-phase summation of the electrical signals received by the elements 5 by introducing electrical delays into each channel uzhdeni -priema. The mode of radiation and reception of ultrasonic vibrations at a certain angle

Claims (1)

can be used in the flaw detection of sheet materials. Formula invented shadows An ultrasonic piezoelectric transducer containing a resonant piezoelectric polarized structure with electrodes, an electrical screen, a damper and a matching layer, characterized in that, in order to increase sensitivity, the piezoelectric structure is made in the form of a matrix of a set of elements consisting of located in one plane and divided between acoustically soft material of piezoceramic rods of rectangular cross section, polarized 1st in the direction perpendicular to their length, on the surface of the piez ceramic rods perpendicular to the direction of polarization, electrodes are deposited, while electrodes deposited on identically oriented surfaces of piezoceramic rods are interconnected and form the first output of the ultrasonic transducer, and electrodes deposited on opposite oriented surfaces form the second terminals of the ultrasonic transducer by a given number elements in the set, and the transverse dimensions of the piezoceramic rod are chosen from d; L. And t "L where d and t are the transverse dimensions of the piezoceramic rod in the direction of polarization and perpendicular to it; D and L t waves in the material rod in the direction of polarization and perpendicular to it. FIG. / Editor P.Geershi Compiled by K. Leonov Tehred M.Hodanich Proofreader L.Pilnpenko Order 5991/43 Circulation 776 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 .-.at..--..---.-..-------------- ---- - - - - - - - --- - Production and printing company, Uzhgorod, Projecto st., 4