【作者】 王忠顺；

【导师】 李艳宁；

【作者基本信息】 天津大学 ， 测试计量技术及仪器， 2006， 硕士

【摘要】 作为一种高灵敏度的传感器件,微悬臂梁的应用极为广泛,最初是应用于原子力显微镜(AFM)上,它的使用使AFM不仅具有原子级分辨力的显微功能,还能够探测探针和样品间的原子级作用力。微悬臂梁有两种工作模式,即弯曲模式和共振模式。在共振模式下,微悬臂梁具有很宽的动态范围和很高的分辨率,因此利用微悬臂梁共振频率进行检测的方法越来越受到人们的关注。根据理论分析,微悬臂梁的共振频率与其有效质量的1/2次幂成倒数关系,当被测物质吸附于微悬臂梁上后,微悬臂梁的共振频率减小,通过检测微悬臂梁共振频率的变化可以进行被测物质的定量分析,利用这个原理可以构建以微悬臂梁为传感元件的系统。压电微悬臂梁由于镀于其上的压电层在振动时会产生压电电流,压电电流的大小表征了微悬臂梁的振动情况,这就为微悬臂梁共振频率的检测提供了电学的检测手段。本文的主要内容包括:1.微悬臂梁的振动理论模型,微悬臂梁在空气和液体中的共振频率和微悬臂梁质量的关系,共振频率变化量和被测物质量的关系,压电薄膜振动时产生的压电电流与微悬臂梁振动之间的关系;2.压电微悬臂梁共振频率的电学检测方案;3.微悬臂梁生物传感器测量探头的设计,包括机械结构和前置放大电路;4.微悬臂梁生物传感器硬件电路的设计,包括激励电路和信号采集电路的设计;5.激励系统、信号采集与处理系统软件设计及相应的上位机软件设计;6.系统调试、实验及结果分析。更多还原

【Abstract】 As a high sensitive sensor, micro-cantilever has a large scope of application. The first use of it in atom force microscope (AFM) not only provides AFM with atomic resolution but also makes the atomic interaction force between probe and sample detectable. The micro-cantilever has two kinds of working mode, namely deflection mode and resonance frequency mode. The resonance frequency mode has very wide dynamic range and quite high resolution. According to theoretic analysis, the resonance frequency of micro-cantilever is the reciprocal of its effective mass’s extracting roots. When the analyte is adsorbed onto the micro-cantilever, the resonance frequency of the micro-cantilever decreases, then the quantitative analysis of the analyte can be done by the detection of the resonance frequency change of the micro-cantilever. The system which uses micro-cantilever as its sensitive component can be set up according to the theory mentioned above.The piezoelectric layer on the piezoelectric micro-cantilever will produce piezoelectric current during vibration and the value of piezoelectric current characterizes the vibration amplitude of the micro-cantilever. This provides an electrical measuring method for the detection of the resonance frequency of micro-cantilever.The main content of the thesis is as follows:1.The vibration theoretical model of micro-cantilever, the relation between the resonance frequency and the mass of micro-cantilever in air and in liquid, the relation between the change of resonance frequency and the mass of detected matter, and the relation between the piezoelectric current which produces during the piezoelectric film’s vibrating and the vibration of micro-cantilever;2. The electrical measuring scheme of the resonance frequency of micro-cantilever;3. The design of micro-cantilever biosensor probe, include mechanical structure and pre-amplifying circuitry;4. The design of micro-cantilever biosensor’s hardware circuit, include excitation circuit and signal collection circuit;5. The software design of excitation system, signal collection and process system and the software on PC terminal;更多还原