容栅电子长度测量系统

一、概述线纹电子长度测量系统中通常包括光栅,同步感应器,磁栅和容栅四种测量系统。容栅电子长度测量系统是七十年代末,八十年代初国际上开始发展起来的一种新颖位移传感器,国内在八十年代陆续引进了容栅器件进行组装。容栅测量系统有几种不同的类型,但其基本原理都应用了电容差动感应的原理。本文介绍的是一种高分辨率的容栅电子长度测量系统。二、工作原理图1　　容栅电子长度测量系统的基本原理如图1所示,它包括一个差动电容传感器,在电容传感器的一边至少有一块接收极板,在电容传感器的另一边至少有两块发射极板。电容传感器两边能作相…     

容栅传感器移相原理浅析

目前,国内一些量具厂家引进瑞士Trimos公司的散件组装的电子数显卡尺中使用了容栅传感器。该传感器所输出的信号是一移相信号。本文从该传感器的基本结构出发,对其输出的函数表达式进行了推导,并对其静态和动态特性进行了分析,以供广泛应用该项传感技术时参考。该传感器的48个发射极分成6组,每组各有8个发射极板e_i与定尺上反射极板F的一个节距W相对应。因各组中i相同的e_i与F的相对位置相同,故可将48个e_i和对应的6个F间的电容器简化为容量为c_1(x)～C_8(x)的8个电容器。每个电容器的电容量为实际的一对e_i和F所组成的电容器的容量的6倍。此外,发射极板e_i和接收极板J都位于动尺上,而反射极板F和屏蔽极板D位于定尺上。e_i上     

调焦光路中超精密双等位环平板电容位移传感器研究

在应用共焦显微镜原理实现对超精加工表面的几何量测量中,设计了一种环状的电容位移传感器,对物镜的调焦位移进行测量,使测量光轴从极板的中心孔穿过,测量位移方向与光路的光轴重合,与阿贝原理相符;采用微机电系统(MEMS)工艺加工双等位环电容极板,电容器极板很薄,间隙小于2μm,减小边缘效应附加电容,从而极大地提高了测量的线性和测量精度.设计了处理电路,对该传感器进行了标定,在0～30μm内,其线性度为0.05%,分辨力优于0.01μm.     

数显卡尺容栅定栅母板的研制

一、前言容栅作为测量基准 ,已在生产中运用并充分显示其优越性。容栅式测量系统具有重复性好 ,精度高 ,抗干扰能力强 ,对环境要求不苛刻 ,实现数字化等优点 ;而且相对光栅测量系统而言 ,具有体积小 ,安装调试方便的优越性 ,因此广泛应用于国内外相关领域。为满足研制开发容栅式数显卡尺的需要 ,我们采用接近式光刻原理 ,以激光干涉仪分度修正的方法 ,研制了高精度玻璃体铬层容栅母板 ,并已取得非常可观的经济效益。二、容栅定栅母板的研制1.容栅定栅母板的技术指标 (见图 1)技术要求 :(1)总长Ｌ =4 6× 5 .0 8=2 33.6 8(2 )任意栅距间误差 …     

容栅尺和单片机的接口研究

常见容栅尺不方便和其他计算机系统进行数据通信,针对此问题,提出了一种容栅尺和单片机接口方案,成功实现了容栅尺数据的同步显示及数据通信.对容栅尺的基本原理和数据格式进行了研究,着重对容栅尺和单片机的硬件接口和数据读出及传输方法进行了介绍.经过实际应用证明系统结构简单,成本低,工作稳定可靠,具有一定的推广应用价值.     

电容式数显卡尺的研究

本文在介绍电容式数显卡尺的工作原理和电路系统的基础上,建立了电容传感器的数学模型,并分析了这种卡尺存在的原理性非线性误差。实验表明,缩短发射极板宽度能有效地提高卡尺的精确度。     

单片机与容栅式数显卡尺连接的接口设计

单片机与容栅式数显卡尺连接的接口设计刘蕙石作德（辽宁省计量测试技术研究所，沈阳１１０００６）一、概述容栅式数显卡尺是用容栅测量系统和数字显示器进行读数的一种长度计量器具。容栅式数显卡尺有一数据输出端口，它是一非标准接口。充分利用该接口与单片机及打印机...     

铅酸蓄电池三维网络碳化硅板栅和极板内电流的分布

用有限元方法分析了铅酸蓄电池用三维网络碳化硅板栅和极板内电流的分布.结果表明,与常规板栅相比,三维网络碳化硅板栅与极板内电流分布比较均匀.极耳的形状和位置对板栅和极板内电流分布的影响很大,当极耳具有夹心结构时,电流分布的均匀性有非常明显的改善,尤其是在厚度方向具有类似三明治的极耳夹心结构时,板栅和极板内的电流分布极为均匀,且电流的数值比较小.     

铁电负电容晶体管的研究进展

铁电负电容晶体管的亚阈值斜率可低于60 mV/dec的理论极限,是未来突破晶体管工作电压VDD和器件尺寸进一步减小瓶颈的关键。自2008年低功耗负电容晶体管的概念被提出以来,该晶体管因简单的器件结构和优异的电路性能而一直受到业界学者的广泛关注。然而,这种基于具有负电容特性铁电材料的晶体管的缺点也日渐凸显,特别是负电容的不稳定性对该晶体管的应用造成严重阻碍。相比传统晶体管,负电容晶体管应用于低功耗电路具有两大优势:(1)亚阈值斜率可低于60 mV/dec,降低电路工作电压的同时开关电流比不会下降,静态泄露电流不增加;(2)器件尺寸更小,减小电路面积。然而,负电容晶体管由于铁电材料的滞回特性,在开关电路中具有严重的滞回现象,导致电路逻辑紊乱,无法正常工作。不仅如此,负电容成因的复杂性也使其建模非常困难。因此,近十年来除研究铁电材料种类和参数对器件性能的影响外,研究者们还整理出了决定滞回现象的关键因素,并提出了有效抑制滞回现象的方法。目前,通过调整铁电负电容和晶体管电容的比例,滞回窗口已经可以减小到近乎为零。而与实验图形较吻合的负电容数学模型直到2017年才出现,但模型中的数据还没有科学的测定方法,目前还处于发展完善阶段,仍需要大量的研究和探索。负电容晶体管制备过程简单,工艺和标准CMOS工艺兼容,基底MOSFET制作完成后,将具有负电容特性的铁电材料沉积在栅上形成叠栅。负电容晶体管制作的难点在于稳固铁电和氧化物界面、减少缺陷空位。目前,国内外已出现流片成功的负电容晶体管,成品测试的最小亚阈值斜率可达16 mV/dec,但滞回现象出现的概率非常大,并且在提高器件的疲劳性和稳定可靠性方面还需要投入更多的研究。使用频率较高的负电容材料有PbZrTiO3(PZT)、SrBi2Ta2O9(SBT)、P(VDF-TrFE)、铪基氧化物等,其中铪基氧化物因环保、体积小、性能优异被认为是可投入实际生产的铁电负电容材料。本文探讨了铁电负电容晶体管的工作原理,分析了负电容特性的物理机理和实验测试方法,给出国际上各研究机构在负电容晶体管(NCFET)方面的研究进展情况,最后分析了未来NCFET在器件结构、材料及可靠性方面的发展问题。     

采用容栅技术的液位检测系统设计

采用容栅技术的液位检测系统是指在磁翻柱液位计的基础上采用了容栅传感器．通过液位的变化使得容栅传感器的电容发生改变,进行测量的一种检测系统。它既具有磁翻柱液位计的高密封、防泄漏、可靠性好等优点。又能满足在高温环境下实现电信号的远传。     

光杠杆纳米微位移测量系统中的信号处理

本文提出了一种基于光杠杆原理非接触式的纳米级微位移测量系统.该系统通过光学方法对微位移量进行放大,光学放大倍数高,该系统的理论分辨率可达4nm,实际测得静态分辨率小于10nm.信号处理采用基于高精度一维PSD的信号探测电路,并且通过设计有效地抑制了噪声和干扰.实验中使用PZT作为被测物的微小位移驱动器,与电容测微仪JDC-Ⅱ所测数据进行了验证比较,系统所测得的数据证明了其正确性和可行性.并且该系统受温度影响小,结构简单,便于使用MEMS技术集成和微型化.     

调相型容栅传感器传输函数的误差分析

本文讨论了容栅传感器传输函数对示值误差的表达,分析了传输解调函数的不同组合对误差的影响,并对不同的解调函数在一个空间周期内求得了相等的最大误差。     

Simulation and experimental characterization of a 2-D capacitive micromachined ultrasonic transducer array element

In this letter, a 400-mumx400-mum 2-D capacitive micromachined ultrasonic transducer (cMUT) array element is experimentally characterised, and the results are found to be in good agreement with theoretical predictions. As a receiver, the transducer has a 1.8x10(-7) nm/ radical(Hz) displacement sensitivity, and, as a transmitter, it produces 16.4 kPa/V of output pressure at the transducer surface at 3 MHz. The transducer also has more than 100% fractional bandwidth around 3 MHz, which makes it suitable for ultrasound imaging.     

Capacitive analog transducer of large displacements

Conclusions Test results indicate that a linear analog capacitive transducer is suitable for indicating displacements over a wide range with an error not exceeding 2·10_–5. The design relationships and formulas provided above can be used for evaluating the structural factors and parameters of the transducer, which affect its precision, and to make the transducer meet given requirements with a minimum of trimming work. A capacitive linear analog converter of displacements into an ac voltage amplitude is a sufficiently simple device which can be widely used in systems requiring precise measurement of large displacements and lengths.Translated from Izmeritel'naya Tekhnika, No. 8, pp. 15–18, August, 1968.     

A Linear Variable Differential Capacitive Transducer for Sensing Planar Angles

A linear variable differential capacitive transducer for the measurement of planar angles (from 0deg to 360deg) is presented in this paper. The sensor part of the transducer is made of parallel plates of standard and easy-to-fabricate shapes, and the signal-conditioning electronics are realized, employing a couple of simple relaxation oscillators. The output of the transducer is only dictated by a pair of dc reference voltages, and hence, high accuracy and linearity over the entire range (from 0deg to 360deg) are easily obtained by the use of precision dc reference voltages. Detailed analysis indicates that the sensitivity of the transducer is minimal for variations in different parameters. Experimental results obtained on a prototype transducer that has been built and tested establish the efficacy of the proposed transducer. The worst-case error of the prototype transducer is found to be less than 0.1%.     

Mathematical simulation of a membrane capacitive compensation pressure transducer

The operation of a membrane capacitive pressure transducer with electrostatic compensation of the membrane deformation has been mathematically simulated. It is shown that the theory describing these instruments is incorrect and the error in measuring pressure by them may be as high as 25–29% of the measured value, which makes them inappropriate for use in pressure metrology.     

Capacitive transducer for relative position error galvo mirrors

A transducer was designed to sense small angular displacements of servo-controlled galvo mirrors in rotary optical storage devices. The transducer is differential in nature, and operates on the principle of linear electrical capacitance variation with area overlap of uniquely shaped capacitor plates. These capacitive plates lie in planes normal to the axis of rotation, and consist of many electrically connected wedge-shaped projections aligned radially to the center of rotation. A prototype was fabricated and tested. For optical storage devices, experimentally determined characteristic curves show sufficient linearity and repeatability for relative position error (RPE) feedback applications, at plate spacings of 0.15 mm or less. A design change, for further extending the linear range of the characteristic curve of the transducer beyond RPE feedback requirements, is described. A circuit design to produce voltage variations proportional to differential capacitance changes in the transducer is discussed, and peak-to-peak signal-to-noise ratio is conservatively approximated at 2×10⁴ with 10 kHz bandwidth     

Novel Signal Conditioning Circuit for Push-Pull Type Capacitive Transducers

A novel signal conditioning circuit suitable for push-pull type capacitive transducers is proposed. The circuit developed is capable of providing a linear output over a wide range of values of the physical quantity being measured even when the transducer output has an inverse relationship with the measurand. The push-pull type capacitive transducer becomes an integral part of a relaxation oscillator, the duty cycle ratio of the output of which becomes proportional to the measurand. The various sources of error in the circuit are analyzed, and quantitative expressions to estimate such errors are derived. Results obtained from tests on a prototype indicate that the circuit possesses very low errors     

Input impedance matching of acoustic transducers operating at off-resonant frequencies

The input impedance matching technique of acoustic transducers at off-resonant frequencies is reported. It uses an inherent impedance property of transducers and thus does not need an external electric matching circuit or extra acoustic matching section. The input electrical equivalent circuit includes a radiation component and a dielectric capacitor. The radiation component consists of a radiation resistance and a radiation reactance. The total reactance is the sum of the radiation reactance and the dielectric capacitive reactance. This reactance becomes zero at two frequencies where the impedance is real. The transducer size can be properly chosen so that the impedance at one of the zero-crossing frequencies is close to 50 Ω, the output impedance of signal generators. At this off-resonant operating frequency, the reflection coefficient of the transducer is minimized without using any matching circuit. Other than the size, the impedance can also be fine tuned by adjusting the thickness of material that bonds the transducer plate to the substrates. The acoustic impedance of the substrate and that of the bonding material can also be used as design elements in the transducer structure to achieve better transducer matching. Lead titanate piezoelectric plates were bonded on Lucite, liquid crystal polymer (LCP), and bismuth (Bi) substrates to produce various transducer structures. Their input impedance was simulated using a transducer model and compared with measured values to illustrate the matching principle.     

Certain errors in uncompensated capacitive level gauges

Conclusions Variations of the permittivity and conductivity of the medium produce errors in the measurements of uncompensated capacitive level gauges. For a rapid evaluation of the maximum possible error it is advisable to use diagrams in coordinates of permittivity versus conductivity.When a capacitive level gauge is used in a large tank, it should be placed inside a grounded conducting screen which will reduce the errors due to changes in the electrical properties of the medium. The minimum diameter of the screen is determined by a reduction in the sensitivity of the instrument, the eccentricity of the transducer with respect to the screen, and the rise in other component errors.Translated from Izmeritel'naya Tekhnika, No. 1, pp. 47–50, January, 1967.