共查询到20条相似文献,搜索用时 15 毫秒
1.
《Mechatronics》1999,9(4):329-348
A novel microcontroller-based sensor system has been designed, developed, and validated to find the column height of serum extracted from human blood samples in clinical tubes. The sensor system, based on capacitive principle, can distinguish the change in capacitance due to a change in dielectric properties as a tube held on a linear carriage is passed through the sensor’s probe. Hardware and software were developed for implementing the motion control, data acquisition, transition point algorithm, and communication. The system can measure column heights as long as 76 mm while displaying a final resolution of 1 mm and an accuracy of ±1 mm full scale. The system is also calibration free due to an allowable floating baseline compensated for in the transition point algorithm. Integration of this sensor with an automated aliquoting machine will not only increase the productivity, but remove the health hazard associated with handling human blood samples and its components. 相似文献
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增大传感器振子的质量和静态测试电容可以减小电容式MEMS惯性传感系统的噪声,而深度粒子反应刻蚀工艺由于复杂的工艺原因,当深宽比较大时,不能刻蚀出大质量和大初始电容的传感器.据此,本文研究了一种磁驱动增大检测电容的MEMS惯性传感器,通过电磁驱动器,传感器的静态测试电容可以大幅增加,在梳齿电容上刻蚀阻尼槽后,其机械噪声达到0.61μg每根号赫兹,仿真其共振频率为598Hz,静态位移灵敏度为0.7μm每重力加速度,基于硅 玻璃键合工艺,制作了栅形条电容式惯性传感器,并用电磁驱动的方式测试其品质因子达到715,从而验证了制作工艺的可行性和电磁驱动器改变传感器初始静态测试电容的可行性. 相似文献
3.
Ming-Zhi YangChing-Liang Dai Po-Jen ShihYen-Chi Chen 《Microelectronic Engineering》2011,88(8):1742-1744
The work studies a micro humidity sensor integrated with a seven-stage ring oscillator circuit-on-a-chip fabricated by the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process and a post-process. The structure of the humidity sensor consists of interdigitated electrodes and a sensing film. The sensing film is cobalt oxide nanosheet that is prepared by a precipitation-oxidation method. The sensor, which is a capacitive type, changes in capacitance when the sensing film adsorbs or desorbs water vapor. The ring oscillator circuit is employed to convert the capacitance of the sensor into the oscillation frequency output. The post-process of the sensor includes etching the sacrificial oxide layer and coating the sensing film on the interdigitated electrodes. 相似文献
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The work presented demonstrates the utilization of micro-contact printing of self-assembled monolayers (SAMs) of gold nanoparticles (NPs) to pattern the porous thin metallic film composing the top electrode of an ultra-fast capacitive relative humidity sensor based on miniaturized parallel-plates electrodes. The rest of the device, which occupies an area of only 0.0314 mm2, is fabricated by inkjet printing stacked individual drops of functional materials, namely gold NPs for the bottom electrode and a polymeric humidity sensing layer, on a polymeric foil. Compared to other printing methods, the use of microcontact printing to pattern the top electrode enables the additive transfer of a solvent-free metallic layer that does not interact chemically with the sensing layer, permitting the thinning of the latter without risk of short-circuits between electrodes, and broadening the range of usable sensing materials for detection of other gases. Thinning the sensing layer yields to ultra-fast response devices with high values of capacitance and sensitivity per surface area. The fabrication process is compatible with low heat-resistant polymeric substrates and scalable to large-area and large-scale fabrication, foreseeing the development of low-cost vapor sensing sheets with high space–time resolution, where every sensor would correspond to a pixel of a large array. 相似文献
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This paper describes a CMOS capacitive sensing amplifier for a monolithic MEMS accelerometer fabricated by post-CMOS surface micromachining. This chopper stabilized amplifier employs capacitance matching with optimal transistor sizing to minimize sensor noise floor. Offsets due to sensor and circuit are reduced by ac offset calibration and dc offset cancellation based on a differential difference amplifier (DDA). Low-duty-cycle periodic reset is used to establish robust dc bias at the sensing electrodes with low noise. This work shows that continuous-time voltage sensing can achieve lower noise than switched-capacitor charge integration for sensing ultra-small capacitance changes. A prototype accelerometer integrated with this circuit achieves 50-/spl mu/g//spl radic/Hz acceleration noise floor and 0.02-aF//spl radic/Hz capacitance noise floor while chopped at 1 MHz. 相似文献
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Recently, high-performance flexible pressure sensors have received considerable attention because of their potential application in fitness tracking, human–machine interfaces, and artificial intelligence. Sensitivity is a key parameter that directly affects a sensor's performance; therefore, improving the sensitivity of sensors is a vital research topic. This study developed a dual-layer dielectric structure comprising a layer of electrospun fiber and an array of microcylinders and used it to fabricate a novel high-sensitivity capacitive pressure sensor. A simple, rapid, low-cost, and controllable microstructured method that did not require complex and expensive equipment was adopted. The proposed sensor can efficiently detect capacitance changes by analyzing changes in the fiber and microcylinder structure when compressed. It has high sensitivity of 0.6 kPa−1, rapid response time of 25 ms, ultralow limit of detection of 0.065 Pa, and high durability and high reliability without any signal attenuation up to 10,000 load/unload cycles and up to 5000 bending/unbending cycles. Moreover, it yielded favorable results in real-time tests, such as pulse monitoring, acoustic tests, breathe monitoring, and body motion monitoring. Furthermore, experiments were conducted using a robotic arm, and the obtained results verify that the sensor has different capacitance responses to objects with different shapes, which is crucial for its future applications in smart machinery. Finally, the sensors were arranged as a 6 × 6 matrix, and they successfully displayed the pressure distribution in a plane. Thus, the contributions of the capacitance pressure sensor with a dual-layer dielectric structure in the field of high-performance pressure sensors were verified. 相似文献
10.
We demonstrate a printed pressure sensor embedded rubber insole for measurement and analysis of plantar pressure. Unlike the conventional mode of pressure sensing of interdigitated capacitors in which change in dimension of electrodes by external pressure leads to variation of capacitance, for this study, the change in capacitance is entirely led by variation of relative permittivity of the surrounding dielectric medium with applied pressure. The measured sensitivity of the sensor is 4.3 V/MPa and shows high linearity in the pressure exerted by human weight. The plantar pressure is detected with locally embedded sensors to register various foot postures at three high-pressure regions: hind-foot, mid-foot, and fore-foot. 相似文献
11.
Novel capacitive fingerprint sensor techniques are described. We propose a novel sensor cell architecture to obtain high sensitivity, wide output dynamic range, and contrast adjustment. For the architecture, three circuit techniques were developed. A sensing circuit with a differential charge-transfer amplifier enhances sensitivity while it suppresses the influence of the parasitic capacitance of the sensor plate. A wide output dynamic range, which is needed for high-resolution analog-to-digital (A/D) conversion, is achieved by transforming the sensed voltage to a time-variant signal. Finally, the sensing circuit includes an automatic contrast enhancement scheme that uses a variable-threshold Schmitt trigger circuit to distinguish the ridges and valleys of a fingerprint well. The characteristics of a test chip using the 0.5-μm CMOS process show a high sensitivity to less than 80 fF as the detected signal, while the variation of the output signal is suppressed to less than 3% at ±20% variation of the parasitic capacitance. The dynamic range of the time-variant signal is 70 μs, which is wide enough for A/D conversion. The automatic contrast enhancement scheme widens the time-variant signal 100 μs more. A single-chip fingerprint sensor/identifier LSI using the proposed sensing circuit scheme confirms the scheme's effectiveness 相似文献
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《Solid-State Circuits, IEEE Journal of》1986,21(6):1045-1056
An integrated circuit has been designed, built, and testing as part of a capacitive pressure transducer. High-accuracy compact micropower circuits utilizing a standard bipolar IC process without any special components or trimming are used. The key circuits for achieving this performance are a Schmitt trigger oscillator and a bandgap voltage reference. The sensor circuits consume 200 /spl mu/W at 3.5 V, can resolve capacitance changes of 300 p.p.m., measure temperature to /spl plusmn/0.1/spl deg/C over a limited temperature range, and presently occupy 4 mm/SUP 2/ on a 2 mm/spl times/6 mm implantable monolithic silicon pressure sensor. Further scaling of the sensor is discussed showing that a reduction of area by a factor of 4 is achievable. 相似文献
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The design and implementation of a fully integrated transceiver front-end for biomedical data is reported. The system targets
the transmission of force data from a distributed sensor system for on-body application. A prototype force transducer patch
is presented whose parasitic capacitance is exploited as coupling capacitance for body-channel transmission. The transceiver
is implemented in 0.35 μm CMOS technology and occupies an area of 0.0178 mm2. It consumes 360 μA of current at a supply voltage of 3 V. Measured results further confirm a transmission rate of 54 kb/s
making the design suitable for use in a distributed pressure sensing network. 相似文献
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提出了一种新的电容式压力传感器.传感器结构为由Al/SiO2/n-type Si等三层方形膜构成的固态电容.传感器采用pn结自停止腐蚀和粘结剂键合的方式制造,制造过程仅需三块掩模板.对不同边长传感器进行测试,在410~1010hPa的动态范围,边长为1000,1200和1400靘的压力传感器,相应灵敏度分别为1.8,2.3和3.6fF/hPa.边长为1500靘的传感器,其灵敏度为4.6fF/hPa,全程非线性度为6.4%,最大滞回误差为3.6%.分析结果表明介电常数变化是引起电容变化的主要原因. 相似文献
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针对应用广泛的电容式传感器信号采集问题,提出了一种具有较大电容动态测量范围的高精度电容式传感器接口电路。该接口电路包括一个电容式有源电桥,以及用于将电容直接转换为频率的张弛振荡器,电路的频率输出用于确定微湿度传感器的响应特性。在基于薄膜的电容湿度传感器上进行了测试,实验结果表明,相比现有的类似电路设计,提出电路的结构更加简单且具有更大的电容测量范围和较高的精度,在1 p-600 p测量范围内的精度(误差百分比)<-2.14%,接口电路灵敏度为4.91 Hz/ppm,且输出频率与电容变化成线性关系。 相似文献
17.
A telemetric pressure sensor system for biomedical applications 总被引:1,自引:0,他引:1
Ginggen A Tardy Y Crivelli R Bork T Renaud P 《IEEE transactions on bio-medical engineering》2008,55(4):1374-1381
A new implantable pressure sensor for long-term monitoring of intracranial pressure is presented. The sensor is powered by telemetry and can be interrogated wirelessly. A capacitive pressure transducer, whose capacitance is converted to a frequency-encoded signal by an application-specific integrated circuit (ASIC), senses the absolute pressure. The pressure-encoded signal, the ASIC input voltage, and onboard calibration parameters are transmitted to an external reading unit. The proposed novel packaging solution is designed for long-term stability and reliability of the sensor. The accuracy of sensor at body temperature is better than 2 mbar across a pressure range of 600-1200 mbar. The sensor is 13 mm in diameter and 4.5 mm in height. 相似文献
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Tao Cheng Xuan-Li Yang Sheng Yang Lang Li Zhong-Ting Liu Jie Qu Chao-Fu Meng Xiang-Chun Li Yi-Zhou Zhang Wen-Yong Lai 《Advanced functional materials》2023,33(5):2210997
Flexible transparent supercapacitors (FTSs) have aroused considerable attention. Nonetheless, balancing energy storage capability and transparency remains challenging. Herein, a new type of FTSs with both excellent energy storage and superior transparency is developed based on PEDOT:PSS/MXene/Ag grid ternary hybrid electrodes. The hybrid electrodes can synergistically utilize the high optoelectronic properties of Ag grids, the excellent capacitive performance of MXenes, and the superior chemical stability of PEDOT:PSS, thus, simultaneously demonstrating excellent optoelectronic properties (T: ≈89%, Rs: ≈39 Ω sq−1), high areal specific capacitance, superior mechanical softness, and excellent anti-oxidation capability. Due to the excellent comprehensive performances of the hybrid electrodes, the resulting FTSs exhibit both high optical transparency (≈71% and ≈60%) and large areal specific capacitance (≈3.7 and ≈12 mF cm−2) besides superior energy storage capacity (P: 200.93, E: 0.24 µWh cm−2). Notably, the FTSs show not only excellent energy storage but also exceptional sensing capability, viable for human activity recognition. This is the first time to achieve FTSs that combine high transparency, excellent energy storage and good sensing all-in-one, which make them stand out from conventional flexible supercapacitors and promising for next-generation smart flexible energy storage devices. 相似文献
19.
Filip Tavernier Michiel Steyaert 《Analog Integrated Circuits and Signal Processing》2011,66(2):277-283
A new TIA topology with enhanced bandwidth is presented in this paper. By adding an extra capacitive feedback loop to the
resistive feedback TIA, bandwidth and sensitivity are increased without sacrificing the low power consumption. It is shown
that this topology is superior to the self-compensated TIA when the photodiode is integrated on the same die as the TIA. An
implementation is presented that boosts the bandwidth by a factor of 9 and reduces the noise by a factor of 4.2 for a photodiode
capacitance of 106 pF, the parasitic capacitance of a POF-compliant 1 mm integrated photodiode in 130 nm CMOS. 相似文献
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设计了一个新型的结构完全对称的双向MEMS电容式惯性传感器.该传感器主要由可动质量块、栅形条、支撑梁、连接梁、阻尼调整梳齿组成.设计的结构采用变电容面积的检测方式,在降低空气阻尼的同时也降低了对DRIE工艺的要求,并通过加大测试信号电压来降低电路噪声,从而提高传感器的分辨率.用有限元工具ANSYS详细讨论了传感器的参数和性能,并模拟验证了设计的双向传感器的交叉效应近似为零.制作了滑膜阻尼测试器件,在大气压下,测得的品质因子可达514,验证了该结构设计可以提高传感器的分辨率和该工艺设计的可行性. 相似文献