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桌面扫描电子显微镜高压控制系统设计

发布时间:2019-01-20 10:10
【摘要】:随着科学技术的发展与进步,扫描电子显微镜不断往高分辨率、多功能、便携小型化方向发展。近年来,我国的扫描电子显微镜有了一定的发展,但是同国外相比,我国在扫描电子显微镜的研制方面技术相对薄弱,制造出的扫描电子显微镜在稳性定、可靠性、分辨率等方面与国外相比还有不小差距,特别是在桌面扫描电子显微镜研制方面,我国尚处于起步阶段,因此桌面扫描电镜的研制有着十分重要的意义。桌面扫描电子显微镜具有体积小巧、操作简便、放大倍数大、分辨率高、抽真空迅速、不用喷金测量不导电样品等特点。目前,主要以美国FEI公司推出的Phenom系列桌面扫描电子显微镜和日本日立公司推出的TM系列桌面扫描电子显微镜为代表占据着世界的主导市场。与国外的大公司相比,国内桌面扫描电子显微镜的研发还是空白,一直依赖进口。因此,加快国内自主品牌桌面扫面电子显微镜的研发,对于打破国外垄断、满足国内市场需要,具有重要意义。本论文主要介绍了在企业研究生工作站,结合企业的产品研发项目,着重研究设计桌面扫描电子显微镜中的高压控制系统。本论文的设计内容主要分为两个方面,一是高压控制系统的硬件电路设计,主要介绍了嵌入式控制模块、数模转换模块、电子束流检测模块、加速电压控制模块、灯丝电压控制模块、升压和倍压电路模块、灯丝电源模块等设计;二是高压控制系统的软件设计,主要介绍了高压控制系统的软件架构、接口设计和主程序设计,而主程序设计又包括电压信号产生程序设计和振荡波程序设计。本设计主要是针对桌面扫描电子显微镜中高压系统的小型化、低噪声(适合办公室使用)、可靠性高、快速、自动控制等特点进行设计。本论文的创新点如下:(1)设计采用STM32F103微控制器作为主控芯片,结合FPGA技术,完成对高压系统的控制。(2)高压发生器电路采用灌封胶灌封工艺,显著的缩小了电路板体积,实现了高压发生器小型、模块、固态化。(3)采用高性能运算放大器OPA177,并采用负反馈放大电路实现了高压的稳定。(4)设计电子束流状态异常判断模块,当电路或者真空异常时,系统能够准确的判断,并且及时的关闭高压系统。
[Abstract]:With the development of science and technology, scanning electron microscope (SEM) has been developing towards high resolution, multi-function and portable miniaturization. In recent years, the scanning electron microscope (SEM) in our country has developed to a certain extent. However, compared with foreign countries, the technology of developing scanning electron microscope in our country is relatively weak, and the scanning electron microscope manufactured is stable and reliable. There is still a large gap between China and other countries in terms of resolution, especially in the development of desktop scanning electron microscope (SEM), which is still in its infancy in China, so the development of Desktop scanning Electron Microscopy (SEM) is of great significance. Desktop scanning electron microscope has the advantages of small volume, simple operation, large magnification, high resolution, rapid vacuum pumping, and no need of gold spray to measure non-conductive samples. At present, the leading market in the world is mainly represented by Phenom series desktop scanning electron microscope and TM series desktop scanning electron microscope introduced by FEI Company of USA and Hitachi Company of Japan. Compared with large foreign companies, domestic desktop scanning electron microscope research and development is still blank, has been dependent on imports. Therefore, it is of great significance to accelerate the research and development of domestic independent brand desktop scanning electron microscope to break foreign monopoly and meet the needs of domestic market. This paper mainly introduces the design of high voltage control system in the desktop scanning electron microscope (SEM) based on the product research and development project of the enterprise graduate workstation. The design content of this paper is divided into two aspects: one is the hardware circuit design of the high voltage control system, mainly introduces the embedded control module, the digital-to-analog conversion module, the electronic beam current detection module, the acceleration voltage control module. Filament voltage control module, voltage boost and voltage doubling circuit module, filament power module and other design; The second is the software design of the high voltage control system, which mainly introduces the software architecture, interface design and main program design of the high voltage control system, and the main program design includes the voltage signal generation program design and the oscillation wave program design. The design is mainly aimed at the miniaturization, low noise (suitable for office use), high reliability, fast and automatic control of the high voltage system in the desktop scanning electron microscope. The innovations of this paper are as follows: (1) the STM32F103 microcontroller is used as the main control chip and the FPGA technology is used to control the high voltage system. (2) the high voltage generator circuit adopts the technology of sealant filling and sealing. Significantly reduced the size of the circuit board, the realization of a high-voltage generator small, modular, solid-state. (3) the use of high-performance operational amplifier OPA177, The negative feedback amplification circuit is used to realize the stability of high voltage. (4) the module for judging the abnormal state of electron beam is designed. When the circuit or vacuum is abnormal, the system can judge accurately and close the high voltage system in time.
【学位授予单位】:南京师范大学
【学位级别】:硕士
【学位授予年份】:2015
【分类号】:TN16;TP273

【参考文献】

相关期刊论文 前2条

1 陈翔;王丛岭;杨平;廖理;;倍压整流电路参数分析与设计[J];科学技术与工程;2012年29期

2 张德添;刘安生;朱衍勇;;电子显微技术的发展趋势及应用特点[J];现代科学仪器;2008年01期



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