Design And Implementation Of Multi Frequency Ultrasonic Power Transducer Base On Lithium-Niobate Single Crystal

With the continuous development of science and technology,ultrasound is widely used in medical,military,industrial and agricultural fields.Especially in the medical field.On the application of ultrasound technology in the medical field since 1942,ultrasound has gradually become one of the main methods for the diagnosis of non invasive examination in the field.Common equipment are A type ultrasonic diagnostic instrument,B type ultrasonic diagnostic equipment,echocardiography,etc.This kind of equipment uses the ultrasonic imaging technology to carry on the examination and the diagnosis to the human body internal organs and the pregnant woman.The application of ultrasound has played a great role in the development of medical treatment.However if the sound intensity(ultrasonic power)exceeds a certain limit,the human body will produce biochemical reactions in the use of ultrasound technology to the human body.According to the experiment,it is proved that have a great influence on the growth of the fetus,especially on the fetal villi and chromosomes,and so on.Therefore,the measurement of ultrasonic power is of practical significance.Standard ultrasonic power transducer is a device that provides standard ultrasonic power source output and it has an important position in the ultrasonic power measurement system.Also it has the ultrasonic power values of the connecting role.The current development direction of ultrasonic transducer is high power,low voltage drive,high frequency,thin film,miniaturization and integration.The frequency of Germany's PTB laboratory standard ultrasound power device has reached 16 MHz or more,even multi frequency.However,in the study of ultrasonic transducers,the main direction of the domestic ultrasonic power reference and the auxiliary reference is the single frequency point of the high-frequency ultrasonic power transducer.At present,the highest frequency of ultrasonic power transducer is 18.5MHz.In China,the output power is limited due to the ultra high frequency ultrasonic power transducer is very thin.Aiming at the problem of high frequency ultrasonic power transducer wafer,this topic uses low frequency lithium lithium and study it's two times,three times and even several times frequencies.The experimental results show that it is able to realize the stable output ultrasonic power of multi frequency ultrasonic power transducer.This topic is design and implementation of multi frequency ultrasonic power transducer base on Lithium-Niobate single crystal.The focus of this paper is to develop a high stability,high frequency and wide power range for the source of the ultrasonic power transducer.The main research contents include:(1)By comparing the piezoelectric materials,The substrate of the study was selected as the lithium.Study found that the most ideal way to cut the chip is to use 36 degrees Y-cut rotated.Determine the relationship between frequency and wafer thickness by looking up the relevant data,in that to determine the thickness of the wafer.The fundamental frequency is about 2.5MHz.The required wafer thickness is calculated to be 1.25 mm.Chip design is completed,and then the electrode processing.The processing technology of magnetron sputtering coating is used to process the electrode.(2)The electric matching of the ultrasonic power transducer is carried out by using the series inductance.After making the corresponding inductance of the coil,the electric conjugate match on the three frequency points is realized.And measurement of relevant parameters of an impedance analyzer.(3)The measurement of ultrasonic power output of the designed multi frequency point ultrasonic power transducer based on the national measurement reference device of ultrasonic power.Through the operation of the specific experimental process,the integrity of the experimental data is obtained.Correlation data analysis of impedance,frequency and ultrasonic power is to verify the parameters and indexes of the multi frequency point ultrasonic power transducer.The research of multi frequency ultrasound power transducer is a reliable technique to provide reliable technical support for the traceability of ultrasonic power.It provides the guarantee of the value of the ultrasonic power output of medical ultrasonic instrument.The research of the subject has high engineering application value.