【作者】 杨俊；

【导师】 曾亦可；

【作者基本信息】 华中科技大学 ， 微电子学与固体电子学， 2010， 硕士

【摘要】 热释电系数是评价热释电材料的热释电性的重要指标,在热释电系数测量没有形成统一标准的情况下,准确的测量热释电系数在热释电材料研究中显得至关重要。本文宗旨是在前人研究的基础上,改进原测试系统的不足,研制出一台基于单控制串口的反馈控制型热释电系数测试系统,实现对热释电系数的准确评价。新测试系统依然采用直接法,在硬件和软件上对原系统做了大量改进。硬件上的改进:设计了串口译码电路,实现由单串口控制四路转换的功能;重新调校了前置转换放大电路,使其对正负电流具备相同的放大范围;放弃了原系统使用时间继电器控制加热的方式,采用由计算机反馈控温的方法;重新设计了系统的屏蔽抗干扰体系,减小外界干扰对测量结果的影响。软件上的改进:按照现代人机交互界面的设计思想,重新设计了测试软件系统,美化软件界面,完善软件功能,实现了全自动测量;设计了具有针对性的计算机弱反馈控温算法,为测试样品提供稳定的匀速升温环境;提出了由标准铌酸锂样品的升温速率拟合待测样品升温速率的方法,弥补了无法测量热释电样品实际升温速率的不足;改善电流滤波算法,并加入了热释电电流的差错处理机制。最终完成新测试系统的整体调试,使用铌酸锂、钽酸锂单晶对测试系统进行验证,测试结果符合国际公认标准,并对多种热释电材料进行测试研究,其结果符合国内外研究报道水平。研究结果表明,本系统达到实用化程度。更多还原

【Abstract】 The pyroelectic coefficient is the most important indicator to evaluate the pyroelectric effect of pyroelectric materials. In case that there is no uniform standard for measurement of the pyroelectric coefficient, how to accurately measure the pyroelectric coefficient is critically important in the study of pyroelectric materials. The purpose of this thesis is to improve the lack of the original test system, and develop a new pyroelectric coefficient testing system with single serial port of computer feedback control for accurate evaluation of pyroelectric coefficient.The new testing system is still using the direct method, and a lot of improvements on the hardware and software have been done on the original system.Improvements of hardware are as follows: (1) designing a serial port decoding circuit to achieve the function of four-way conversion from a single serial control, (2) recalibrating the pre-conversion amplifier circuit to obtain the same positive and negative current zoom range, (3) adopting computer feedback temperature control method in replacement of the original heating control means of using the time relay, (4) redesigning the anti-jamming system to reduce interference on the measurement results.Improvements of software are as follows: (1) modifying the structure of testing softwareto achieve user-friendly computer interface, beautifying software interface, improving the software features, and achieving automatic measurement, (2) designing a targeted computer weak feedback temperature control algorithm to provide a stable uniform heating rate environment for the testing sample, (3) proposing the theory of using the change rate of the standard lithium niobate sample temperature to fit the other pyroelectric samples and make up the objection that can not measure the rate of temperature change of pyroelectric sample directly, (4) improving the current filtering algorithm and adding the error handling mechanism using the pyroelectric current. I have completed the overall commissioning of the new test system and verified the functionality of the system with the samples of lithium niobate and lithium tantalate single crystals. The testing results are consistent with internationally recognized standards. Many other types of pyroelectric materials have been measured by this new system and the results are in good agreement with the reported values from the domestic and foreign research literatures.更多还原