弛豫铁电单晶器件的应用电路设计

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1、摘要铁电单晶(1-x)Pb(Mglj3Nb2／3)03-xPbTi03(PMN．PT)具有优异的介电、压电和机电耦合性能，已经被广泛地研究和应用，但目前却很少有合适的应用电路供其使用。这是以为以前的研究都集中在于PMN．PT的生长和材料性能的研究上，因此很少有适用于弛豫铁电单晶的专用电路。在本论文中，我们设计和制备了超声电机的驱动电路；搭建了一套相对成本较低的基于动态法的高灵敏度热释电系数测试系统，硬件系统达到了基于动态法原理测试热释电系数时的高灵敏度要求，实现了针对PMN-PT材料的高精度热释电系数测量，并使用Delphi作为开发平台自行开发一套自动

2、化测试材料的软件，提高了测试的精确度。针对实验室利用压电材料所研制的新型超声波电机，设计和制作出了一种专用驱动电路．该驱动电路由干电池提供直流电源，产生频率范围为lO-lOOkHz，电压峰峰值为0-180V可调的超声波信号．实验结果表明，研制的电路能稳定，能方便地驱动超声波电机良好运转。建立一套基于动态法的高灵敏度热释电系数测试系统。该测试系统平衡点温度误差为0．01℃，达到了动态法对温度稳定性的高要求；同时其测量精度达到O．OlnA范围温度0—80℃，温度调制频率为44．7mHz，满足了动态法测试的要求。测试标准试样钽酸锂单晶薄片的值与文献中动态法测

3、试结果基本相符。关键词：驱动电路；超声电机；压电；热释电AbstractFerroelectric(1-x)Pb(Mgt／3Yb2／3)OrxPbTi03(PMN—PT)singlecrystalshaveexcellentdielectric,，piezoelectricandelectromechanicalpropertiesandhavebeeninvestigatedandusedwidely．However,therearerarelypropercircuitsforthePMN·．PTtouse．Itmaybecausedbythefa

4、ctthattheresearchesweremainlyfocusedonthegrowingandstudyingthepropertiesforthePMN—PT．TherearefewspecialdesigningscircuitstoadaptthePMN-PTsinglecrystals．Inthisthesis，．wedesignedandfabricatethecircuitsfortheultrasonicmotor(USM)andthemeasuringofthepyroelectricpropertiesofrelaxoroba

5、sedferroelectrics，developingaprogramfortheinstrument．Accordingtotheultrasonicmotorsthatwereproposedanddesigned，weanalysedtheultrasonicmotors，simulateedwiththedrivingcircuitanddesignednoveldrivingcircuitsforUSM．Thecircuitscangeneratesignalwiththefrequencybetween10to100kHzandtheva

6、lueofVp-pbelow180v．OurexperimentresultshaveproventhatthecircuitscanconvenientlyandstablydrivetheUSMwithdrybatteriesaspowerSOurCe．Ainstrumentofmeasuringthepyroelectricpropertiesofthesinglecrystalwasfabricatedsuccessfully．Thecurrentsensitivityforthepyroelectriccurrentofthesinglecr

7、ystalarepreciseto0．1nA．Theresultshowsthatthedataofthemeasuringisconsistentwiththeauthoritativedata．Duringtheinvestigationsofdesigningcircuitsonthepyroelectricproperties：．wedevelopaprogramfortheinstrument．Theprogram’functionisthatmeasuringtherelateddataandnotingtheminmemoryautoma

8、ticSOthatthedatawillmorestandardthanwritethemma