MEMS镜片式眼压传感器设计

眼压(IOP)24 h的波动参数是眼科的一个重要的基础指标,目前传统的单个时间点的眼压测量无法有效地实现眼压的持续检测.基于眼压大小与眼角膜曲率的相关性,结合微机电系统(MEMS)微加工工艺和压模工艺,设计了一种基于电感的镜片式眼压传感器,在体外猪眼的实验结果证明了此传感器在眼压一定范围内(12~27 mmHg)可以准确地反映眼压波动情况.     

LTCC高温压力传感器温漂特性研究

研究了利用杜邦951 LTCC材料制备的无线无源压力传感器的温漂特性。通过搭建高温测试系统,对传感器0~600℃内的高温特性进行了测试,结果表明传感器存在较大温度漂移。通过制作无腔传感器和LTCC基片上螺旋电感进行高温特性测试,通过对比分析,确定了造成传感器温漂的主要原因是LTCC材料相对介电常数的变化。结合测试数据和公式推导,得出了600℃时杜邦951 LTCC材料的相对介电常数由常温7.8增大到9.04。     

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).     

眼角膜超声测厚及眼压测量复合传感器设计

眼角膜厚度和眼压是眼球的两个重要生理参量,是诊断屈光不正、青光眼等眼科疾病的重要指标.新型复合传感器能一次性完成两个参量的测量.使用这种传感器,可以提高眼科医学诊断的便利性,同时可以根据角膜厚度修正眼压值.通过超声传感器和使用电磁驱动的压力控制系统相结合,实现两种测量的同步完成.超声传感器采用PZT系列压电复合材料,角膜厚度采用超声波脉冲回波法测量.电磁压力控制根据眼压测量的需求,通过计算得到电磁驱动系统的结构参数和电磁参数.由实验测量结果可知,角膜厚度测量精度在±10μm范围内;电磁压力控制系统的压力范围为0~0.490 N,精度为0.0006 N.该复合传感器测量精度和范围符合传统角膜测厚和眼压计的标准,为二合一眼科仪器研制打下基础.     

A novel fault-tolerant sensor system for sensor drift compensation

The conventional fault-tolerant sensor systems would fail when outputs from incorporated sensors are either noisy or drifting. This paper presents a novel real-time fault compensation method, which uses state estimation and compensation techniques, that the sensor system can perform robust measurements even when outputs from every incorporated sensor are noisy and drifting. In a simulation example, the proposed design can detect and correct the sensor errors (dc bias and drift) in real time. For the dc bias, the minimum detectable offset value is 0.1, which is the same as the standard deviation of the sensor noise. The compensated sensor output is biased at values smaller than 0.02. For the sensor drifts, the proposed method can compensate drifts for the change rate of drifts up to four times faster than that of the signal to be measured. The highest change rate of drifts, that can be compensated by this method, is determined by the standard deviation of the sensor noise.     

Exploitation of aeroelastic effects for drift reduction,in an all-polymer air flow sensor

This paper presents a vibration amplitude measurement method that greatly reduces the effects of baseline resistance drift in an all-polymer piezoresistive flow sensor or microtuft. The sensor fabrication is based on flexible printed circuit board (flex-PCB) technology to enable the potential for low-cost and scalable manufacture. Drift reduction is accomplished by discriminating the flow-induced vibration (‘flutter’) amplitude of the microtuft-based sensor as a function of flow velocity. Flutter peak-to-peak amplitude is measured using a microcontroller-based custom readout circuit. The fabricated sensor with the readout circuitry demonstrated a drift error of 2.8 mV/h, which corresponds to a flow-referenced drift error of 0.2 m/s of wind velocity per hour. The sensor has a sensitivity of 14.5 mV/(m/s) with less than 1% non-linearity over the velocity range of 5–16 m/s. The proposed vibration amplitude measurement method is also applied to a sensor array with a modified structure and a reduced dimension, which demonstrated a sensitivity of 13.2 mV/(m/s) with a flow-referenced drift error of 0.03 m/s of wind velocity per hour.     

基于绝压传感的气压测试系统设计

气压测量是人们生产生活中必不可少的重要参数.针对我国气压测量大多采用机械式气压表,存在精度低、读数误差大、易损坏、不便携带等缺点,设计了一种以压力传感器及其测量电路为核心的压力测试系统,来代替传统机械式气压表.测试结果表明,系统具有精度高、体积小、高稳定性、系统特性优良等优点,其线性度、重复性误差及迟滞性误差等指标均小于1％,能很好的实现测量气体压力的功能,为人们的生产生活带来便利.     

A readout circuit for an intra-ocular pressure sensor

A readout circuit for a passive telemetric intra-ocular pressure (IOP) sensor is being developed. The intra-ocular sensor consists of a capacitive pressure sensor in parallel with a planar coil. This inductor–capacitor (LC) resonant circuit transduces the pressure into a shift of resonance frequency. A voltage controlled oscillator (VCO) is used to excite the sensor over a large frequency range (20–40 MHz), hereby detecting resonance of the internal sensor, and thus enabling the measurement of the intra-ocular pressure. This low power circuit is extremely compact, making it suitable for long-term ambulant patient monitoring. The circuit allows wireless readout of the smallest pressure transducers. Tests show promising results at mutual coil distances up to 7.5 mm.     

可植入眼压微传感器

对眼压进行长期、连续和实时的监测对于提高青光眼的诊治水平具有重要的意义.可植入眼压微传感器能够实现对眼压的长期连续监测.总结了国内外的可植入眼压微传感器技术;归纳了不同种类的可植入眼压微传感器的工作原理,并对不同的可植入眼压微传感器技术进行分类和比较;讨论了可植入眼压微传感器的各技术模块.     

光纤压力传感器

提出一种记数法布里珀罗(F-P)腔的干涉条纹的光纤压力传感器,可以用于易燃、易爆的环境。阐述了它的设计原理、参数的设置和误差的讨论及改进。试验结果表明:光纤F-P腔脉冲计数压力传感器结构简单、成本低、抗干扰能力强,具有很大的测量范围和分辨力,分别达到10m和0.02%。     

Compensation of the temperature-dependent offset drift of a Hall sensor

We present a method to cancel the offset of a Hall sensor and compensate its temperature-dependent drift. We adapt and improve a compensation technique based on a correction using the input voltage. A more accurate compensation for the temperature drift is obtained by an offset calibration at two different temperatures. To decrease the calibration time, we propose a procedure for fast heating of the sensor. It consists of forcing a current pulse through a p-n junction of the sensor. Since the resistance of a forward-biased diode is small, this principle is compatible with low-voltage applications. After correction, the resulting offset is less than two percent of the initial offset over the temperature range −10 to +60°C. The corresponding residual equivalent offset is lower than 250 μT.     

Polysilicon nanofilm pressure sensor

Utilizing 80 nm polysilicon nanofilm as piezoresistors, a pressure sensor with high performance is developed. The complete fabrication process is described. The pressure properties of the sensor were measured at the temperature from 0 to 200 °C. For 0.6 MPa full scale pressure, the sensitivity is 23.00 mV/V/MPa at 0 °C and 18.27 mV/V/MPa at 200 °C, the temperature coefficient of sensitivity (TCS) is about −0.098%/ °C without any compensation. The temperature coefficient of offset (TCO) is about −0.017%/ °C. Because of the good piezoresistive and temperature characteristics of polysilicon nanofilm, the pressure sensor demonstrates a better performance.     

PVDF土压力传感器

为适应土中动态压力测试的需要,研制了PVDF土压力传感器;介绍了传感器的测压工作原理及传感器的结构,并给出了传感器在某爆炸冲击试验中的应用情况;试验表明,PVDF压力传感器适合于爆炸荷载作用下土中压力测量。     

Polycrystalline diamond pressure sensor

The piezoresistance and other characteristics of boron doped polycrystalline diamond films (PDF's) were determined by analyzing free-standing films that had been formed on silicon. These structures were adhered to a dielectric substrate, and from bending stresses a gauge factor was estimated. Subsequently, a monolithic all-diamond pressure sensor was designed and fabricated, whereby doped diamond resistors reside on a dielectric diamond substrate diaphragm. The process and piezoresistance behavior of their structure is described     

新型波纹管压力传感器

通过对弹性敏感元件的研究 ,设计制造了带有充填物的波纹管 ,解决了薄壁波纹管不能承受高压的难题 ,又保持了较高的灵敏度。代替了常规的压力传感器中的橡皮膜和弹簧 ,重新制作了新型的压力传感器并在 1994年获得了国家专利证书     

High-temperature ceramic pressure sensor

A pressure microsensor for working at high temperature has been developed. The device consists of a tantalum nitride thin film, patterned on a Wheatstone bridge configuration, sputter-deposited onto thermally oxidized silicon wafers with an aluminium interconnection layer and a silicon dioxide passivation. The microsensors present a low temperature coefficient of resistance and good long-term stability. The sensitivity is 0.15 mV (V bar)⁻¹ with low sensitivity drift and low combined non-linearity and hysteresis in the pressure range 0–10 bar.     

膜盒式压力传感器的应用

介绍了远距离冷气压力表传感器和指示器的基本构造及二者的电路连接关系 ,利用简单的电路实现了远距离冷气压力的测量。详细论述了远距离冷气压力表的测压原理。     

基于GABP-KF的WSN数据漂移盲校准算法

针对无线传感器网络节点容易产生数据漂移的问题,提出了一种新型的跟踪和校准节点数据流漂移的算法。首先使用基于遗传算法优化的BP神经网络对目标节点和其邻居节点间的时空相关性进行建模,以获得目标节点的预测值,再使用卡尔曼滤波器跟踪和校准该节点的数据漂移。针对不同的真实数据集进行仿真实验显示,该方法相较于其他对比方法模型预测精度更高,漂移校准性能更好。实验结果表明,该算法可以精确地校准传感器节点的数据漂移,提高节点数据的可靠性。     

面向工业过程软测量建模的概念漂移检测综述

基于数据驱动的软测量模型广泛用于工业过程中产品质量与环保指标等难测参数的在线测量,该过程中存在的概念漂移问题易导致模型精度下降.如何有效识别过程概念变化并精准检测漂移样本是提高模型测量性能的关键.本文总结并分析目前漂移检测的研究思路与进展,为面向工业过程软测量的漂移检测算法提供设计指导.首先,介绍了概念漂移的通常定义与...