新型厚膜陶瓷电容式压力传感器感压元件研究

采用厚膜传感技术研制新型陶瓷电容式压力传感器,重点开展厚膜陶瓷电容感压元件的制备工艺和混合集成化研究。详细阐述了双电容感压元件的工作原理、结构设计、工艺制备方法及性能测试。试验结果表明:研制的感压元件性能良好,非线性误差低于1.0%,迟滞误差小于0.5%,测试电容和参考电容温度系数近乎一致。     

A novel high sensitive MEMS intraocular capacitive pressure sensor

This paper presents a novel high sensitive MEMS capacitive pressure sensor that can be used as a part of LC tank implant circuit for biomedical applications. The pressure sensor has been designed to measure pressures in the range of 0–60 mmHg that is in the range of intraocular pressure sensors. Intraocular pressure sensors are important in detection and treatment of an incurable disease called glaucoma. In this paper two methods are presented to improve the sensitivity of the capacitive pressure sensor. First low stress doped polysilicon material is used as a biocompatible material instead of p++silicon in previous work (Gu in Microfabrication of an intraocular pressure sensor, M.Sc Thesis, Michigan State University, Department of Electrical and Computer Engineering, 2005) and then some slots are added to the poly Si diaphragm. The novelty of this research relies on adding some slots on the sensor diaphragm to reduce the effect of residual stress and stiffness of diaphragm. The slotted diaphragm makes capacitive pressure sensor more sensitive that is more suitable for measuring intraocular pressure. The results yield a sensor sensitivity of 1.811 × 10^?5 for p++silicon clamped, 2.464 × 10^?5 1/Pa for polysilicon clamped and 1.13 × 10^?4 1/Pa for polysilicon slotted diaphragm. It can be seen that the sensitivity of the sensor with slotted poly Si diaphragm increased 6.2 times compared with previous work (clamped p++silicon diaphragm).     

A novel capacitive pressure sensor based on sandwich structures

This paper presents a sandwich structure for a capacitive pressure sensor. The sensor was fabricated by a simple three-mask process and sealed in vacuum by anodic bonding. The sensor, which utilizes a combined SiO/sub 2//Si/sub 3/N/sub 4/ layers as the elastic dielectric layers, exhibits high sensitivity. Mechanical characteristics of the sensor are theoretically analyzed based on a composite membrane theory and evaluated by use of finite element analysis (FEA). Square membrane sensors with side lengths of 800 /spl mu/m, 1000 /spl mu/m, 1200 /spl mu/m, and 1500 /spl mu/m were fabricated, providing a measured sensitivity of 0.08 pF/kPa, 0.12 pF/kPa, 0.15 pF/kPa, and 0.2 pF/kPa, respectively. The nonlinearity of the sensor is less than 1.2% over a dynamic range 80-106 kPa and the maximum hysteresis is about 3.3% to the full scale capacitance change. The TCO at 101 kPa is 1923 ppm//spl deg/C. All the electrodes of the sensor are leaded from the top side of the chip. Residual pressure in the sealed cavity at room temperature is evaluated by a pressure scanning test, indicating about 8 kPa. Comparison of experimental results with theoretical analysis shows that change of capacitance for the sandwich structure under pressure is mainly due to variation of the dielectric constant while geometric variations such as the area change of electrodes and the thickness change of dielectric layers is about two orders less than the variation of the dielectric constant. Sensitivity enhancements for the sensor are qualitatively discussed based on the physical effects of strained dielectrics, including electrostriction and flexoelectricity. [1551].     

一种新型电容式力矩传感器设计

为准确、快速地检测力矩,提出了基于电容边缘效应的差动式新型力矩传感器设计.由机械本体和印制电路板(PCB)组成,机械本体上2个感应动电极与PCB上2个对应的感应静电极互相垂直,且为差动式结构.通过电容量/数字转换器检测垂直极板间的电容量,得到“力矩/电容量”转换关系.以商用转矩转速传感器作为标准力矩仪对力矩传感器进行标定与实验验证,结果表明:差动式电容力矩传感器具有较高的灵敏度、重复度和线性度等优点,其灵敏度约为非差动式的2倍且非线性误差更小.     

High-performance capacitive humidity sensor with novel electrode and polyimide layer based on MEMS technology

A high-performance capacitive humidity sensor based on a newly designed electrode and a polyimide (PI) layer is presented in this paper. The humidity sensor consists of a substrate with a cavity, a bottom electrode, a PI sensing layer, and a comb-shaped top electrode with branches. The cavity structure of the substrate was formed to protect the top electrode. In order to enhance the performance of the sensor, the coated PI layer was etched by using an O₂ plasma asher in accordance with the top electrode passivation. After the PI etching, the humidity sensor showed a high sensitivity of 506 fF/% RH and a fast response time of less than 6 s, which is attributed to the increased contact area between the PI layer and moisture, and shortened moisture absorption path into the PI layer. Further characterizations were carried out to measure the effect of temperature, hysteresis, and stability. The humidity sensor showed a hysteresis of 2.05% RH, little temperature dependence, and stable capacitance value with maximum 0.28% error rate for 24 h.     

基于电容式套管的电子式电压传感器的研制

在分析电容式套管结构和分压原理的基础上,采用传感器与一次高压设备融合技术,设计了基于套管次末屏以及末屏分压的电压监测传感器,并通过实验验证了该传感器的有效性.测试结果表明:该传感器能可靠地采集套管传过来的工频电压和冲击电压信号.     

基于柔性热膜传感器的流体壁面剪应力测量系统

为实现流体壁面剪应力在线测量,设计了一种基于柔性热膜传感器的流体壁面剪应力测量系统.通过分析柔性热膜传感器作用机理,研发了基于LTZ1000电压基准的高精度恒流驱动电路,开发了基于DSP2812,AD7609的18位真差分同步高速数据采集模块,并通过温度补偿方法对传感器输出信号进行了环境温漂修正.系统性能测试表明:当流场温度在10 ～30℃范围变化时,剪应力测量分辨率在0～10 Pa范围内优于0.2Pa,流体温度变化引起的系统输出信号偏差为0.6％/℃,满足实际流体壁面剪应力测量要求.     

基于电容式传感器的粮食水分测量仪

少量样品的非破坏性水分快速、准确的测量是粮食工业中需要解决的关键技术。在研究了电容式传感器的原理和含水介质导电浴盆效应的基础上提出了用电容式传感器来测量粮食水分的原理。实验结果表明,此仪表准确性高,重复性好。     

电容式压力传感器温度补偿的RBF神经网络

提出了一种基于径向基函数 (RBF)神经网络的电容式压力传感器温度补偿方法。通过实例说明了这一方法的应用 ,结果表明采用这种方法能在不同的压力下及温度变化较大时 ,对电容式压力传感器进行有效的温度补偿 ,并且能得到很高的补偿精度。     

基于MEMS技术的微电容式加速度传感器的设计

给出了一种基于MEMS技术制作的微电容式加速度传感器的结构及工艺。为了准确地把握这种微电容式加速度传感器的力学和电学特性,仔细地建立了它的力学模型。在此基础上,详细分析了它的动态特性———模态。并用有限元的方法分析和计算了微电容式加速度传感器的加速度与电容信号的非线性输入输出关系,并结合实测参数验证了模型的有效性。最后提出了一种详细的有效的基于MEMS技术的微电容式加速度传感器的结构以及加工工艺流程。基于MEMS技术制作的微电容式加速度传感器具有结构简单、工作可靠和工作范围大的特点。根据这套方法,可以比较方便地设计并加工不同测量要求的加速度计。     

A flexible capacitive tactile sensor array with micro structure for robotic application

A flexible capacitive tactile sensor array with micro needle structure is proposed in this paper for robotic application. Micro needle layer made of polydimethylsiloxane （PDMS） is sandwiched between the upper electrode layer made of PDMS and the bottom electrode layer fabricated on polyester （PET） film. The PDMS material renders the device adequate flexibility as it can be rolled into a cylinder. The single cell size in the fabricated 4 ~ 4 sensors array is 0.7 ~ 0.5 cm2 and the initial capacitance of each cell is 0.86 pF. The fabricated cell shows a sensitivity of 3.26%/mN within the full scale range of I kPa. The micro needle structure gives better repeatability and stability. The maximum error during each measurement is about 3.2%, while the minimum error is about 1.2%.     

基于有限元的电容临近传感器研究

建立了电容临近传感器的三维仿真数学模型,用FEA对不同参数的传感器进行了仿真,比较分析了被测物距离、电极宽度、电极长度间隙比等对传感器灵敏度的影响,并与理论计算进行比较,结果表明:测量系统的灵敏度与电极宽度和电极长度间隙比近似成正比,与被测物距离近似成反比.该研究对电容临近传感器的结构设计有指导意义.     

Development of a novel piezoresistive thin film sensor system based on hydrogenated carbon

Thin film sensor systems based on hydrogenated carbon have the advantage to combine two very important characteristics in order to be used in measurement engineering: Firstly, the sensory layer demonstrates piezoresistive behavior and secondly its good properties related to hardness and wear resistance lead in a tribologically stable system. Therefore, the thin film sensor systems can be applied into the main distribution of force within machine parts or used for universal interchangeable sensor systems, e.g. sensory washers. In this article the deposition of a self-contained thin film sensor system on a large technical component (spindle shaft) is shown. The spindle shaft with a length of 480 mm and an outer diameter of 90 mm is part of a belt driven machining spindle for planing machines in woodworking industries. In order to establish a measurement system, which allows monitoring the clamping force of the tool holder and the imbalance of the mounted tool, the thin film sensor system was directly applied to the front surface of the spindle shaft. For this application a novel self-contained thin film sensor system was developed, which consists of an alumina layer for electrical isolation, a chromium layer to establish internal sensor electrodes, a piezoresistive hydrogenated carbon layer (1 μm) and a second covering wear resistance and insulation layer (silicon and oxygen modified carbon layer). The piezoresistive sensor layer and the top layer are part of the diamond like carbon layer family (Robertson, Diam Relat Mater 12:79–84, 2003; Bewilogua et al. DLC based coatings for tribological applications, pp. 67–75, 2006; Biehl et al. Thin Solid Films 515(3):1171–1175, 2006, Novel measurement and monitoring system for forming processes based on piezoresistive thin film systems. Springer Verlag, pp. 879–883, 2010).     

一种新型无源电容式温度传感器的制备与测试

为了实现高温、机械旋转和密闭空间等恶劣环境中的原位温度测量,以高居里点的铁电陶瓷为温度敏感介质材料,在传统低温共烧陶瓷(LTCC)工艺的基础上,采用牺牲层填充技术,保证了制备过程的工艺兼容性,成功制备出了一种基于LTCC衬底的新型无源电容式温度传感器。通过外部读取天线与传感器线圈的互感耦合,实现了从常温至700℃的传感器温度特性测试,测试结果表明:这种电容式温度传感器具有良好的温度敏感特性,其平均灵敏度为-7.33 kHz/℃。     

基于C-SOI工艺的一维MEMS电容式超声传感器阵列

提出了一种新的基于C-SOI工艺制备的电容式微加工超声传感器(CMUT)的方法.通过对加工过程中一些关键工艺步骤进行测试,发现所加工的微传感器尺寸与设计尺寸基本一致,且刻蚀的空腔高度均匀,键合效果良好,证明了工艺流程的可行性.此外,通过对所加工的传感器阵列进行测试发现,各阵元谐振频率和静态电容具有良好的一致性,说明以C-SOI工艺加工的CMUT器件满足设计要求,且适宜加工大阵列,这种加工技术使得加工成像阵列成为可能.     

一种基于压力敏感元件的降雨传感器

针对已有降水传感器对强降水测量误差大、测量范围小等不足,研制了一种基于压力敏感元件的雨量智能传感器.设计的传感器硬件南压力敏感元件核心的降雨物理量转换单元、以差分放大和线性处理模拟电路为主的信号处理单元、以高速低功耗嵌入式处理器ARM9为核心的数据计算单元等部分组成;传感器软件上采用广义回归神经网络的函数逼近方法,通过小样本训练建立精确测量模型.测量降雨作用在压力传感器上的压力大小及其对时间的变化,利用广义回归神经网络模型可计算得到精确雨量.试验表明,该传感器不仅解决了强降水等原因引起的雨量测量不准的问题,具有测量量程宽、精度高等优点.     

基于超支化聚合物的声表面波化学毒剂传感器

基于声表面波（SAW）技术的化学毒剂传感器在检测下限、响应速度以及减小温度、湿度交叉敏感等方面还需进一步提高。提出了在SAW双端口谐振器上涂敷超支化聚合物的方法提高传感器的检测下限和灵敏度。通过建立Van Dyke模型,分析了敏感膜对SAW化学毒剂传感器Q值、插入损耗以及电路阻抗匹配的影响。利用谐振器代替延迟线,确保了器件具有插入损耗、高Q值的特点。实验证实,在谐振器的中心栅结构上涂覆聚合物可以减小粘弹性聚合物对谐振器插损、Q值以及输入输出阻抗的影响。对设计的化学毒剂传感器进行了沙林毒剂检测实验,采用315MHz的SAW谐振器结合超支化聚合物膜,检测沙林气体浓度为5．0mg／m^3。实验表明：这种传感器的灵敏度可达到600Hz／mg／m^3,响应时间为50s,恢复时间约为60s。     

基于Sigma-Delta调制的电容传感器设计

提出一种基于Sigma-Delta调制的电容传感器芯片,采用三阶Sigma-Delta调制技术实现了电容到数字信号的直接转换,并通过补偿电容器矩阵扩展可测电容值范围,利用电流饥饿型OTA提高运放电流利用率,降低整体功耗。采用SMIC 0. 18μm CMOS工艺,利用Cadence工具对电路进行仿真验证,在2 V的供电电压下,共消耗电流18. 6μA,0. 8 ms转换时间内,调制器实现三阶噪声整形功能,可测输入电容范围为0～8 pF,并实现良好的线性度。     

基于微变电容式传感器的角度-振动测量方法

利用微变电容式MEMS传感器,设计了一种角度-振动量的检测方法。以RC串联回路直流充放电理论为基础,单片机系统为主体,实现振动量和角度偏移量的检测。经过适当的滤波算法对原始信号进行处理,可以有效地减小噪声的干扰,并快速而准确地分离出基波分量和高次谐波分量,进而得出较好的振动曲线和角度曲线。经实验验证：角度检测和振动检测可同时进行且互不干扰。     

常用新型柔性传感器的研究进展

介绍了常用柔性传感器的特点和分类,对其常用的基底与薄膜材料做了详细介绍.阐述了新型柔性气体、压力、湿度传感器的结构、工艺与性能,介绍了其适用环境和测量范围.将常用普通传感器与柔性传感器的基本特点进行了对比分析.指出了常用柔性传感器发展中的主要制约因素,并对未来研究方向提出了展望.