二线制带隔离膜片的扩散硅液位变送器

由于液位与液体静压力有关 ,因此可以通过静压力测量得到液位的大小。二线制隔离膜片扩散硅液位变送器是利用单晶硅的压阻效应 ,通过电阻的变化 ,得到静压力的大小 ,再通过惠斯登电桥及功能模块电路将静压力转换成电流信号输出 ,从而建立起输出信号与液位的线性对应关系 ,实现对液体深度的测量。还介绍了该种变送器的基本结构、密封方法和一般应用     

扩散硅数字化压力变送器补偿技术

详细介绍了扩散硅压力变送器的特点和现状,提出了对扩散硅压力变送器的数字补偿方案和补偿算法及实际测试结果。该技术提高了产品的整体性能,很好的解决了变送器零点温漂和灵敏度温漂的问题,并通过批量化的生产证实这种技术的正确性。     

新闻之窗

YSK型0.2级扩散硅压力变送器通过技术鉴定天津市自动化仪表厂研制的YSK型0.2级扩散硅压力变送器最近通过技术鉴定。主要技术指标:(1) 测量范围:0～10至0～25kgf/cm~2;(2) 基本误差:0.2%;(3) 使用环境温度:-25～70℃;(4) 量程比:1:3;(5) 防爆等级:本质安全防爆型ibⅡCT5,本质安全隔爆双重型dibⅡBCT5;(6) 供电电源:24V. DC. YSK型0.2级扩散硅压力变送器在天津市第四日用化学厂等单位长期连续运行,经雨淋、暴晒(最高温度达80℃)和强烈的机械振动环境一直工作正常,受到用户     

一种新颖的智能两线制压力变送器

就智能两线制压力变送器，提出了采用DC/DC效率转换的方法解决了变送器智能化的瓶颈问题，即保证输出电流为4mA时整表的正常工作，具体介绍了扩散硅式智能压力变送器的原理框图，电源及DC/DC电路，传感器信号变换电路，CPU及外围电路；V/I转换电路，软件流程图，并进行了功耗计算。该变送器具有较高的性价比。     

温度变送器的制作

温度变送器是由温度传感器配上电子线路组成的测温部件。它的特点是,尽管测温的量程不同,但其输出信号是规范的:如电压信号输出时,其输出为0～5V或0～10V等;如电流信号输出时,其输出为4～20mA。一般的变送器电路是由电源(恒压源或恒流源)、放大器、V/I变换电路等组成,元器件多,调试复杂,尺寸大。随着半导体工艺技术的发展,已可将上述电路集成在一个芯片上,即变送器集成电路。这样一来,变送器变得十分简单,可以自行制作。这里向大家介绍一种用新颖的变送器集成电路XTR101组成的温     

基于CAN总线的高精度数字压力变送器的设计

介绍了一种基于CAN总线的高精度数字压力变送器的设计方案。该压力变送器采用高稳定性扩散硅式压力芯体,信号经调理后由高性能ADuC836单片机进行数据处理,最后通过CAN总线输出压力值,具有精度高、体积小、集成度高、可靠性高、智能化、成本低等特点及在线标定校准和温度补偿功能。     

基于MSP430F4250的压力变送器

传统的(4～20)mA压力变送器大多采用模拟电路构建,采用可调电位器进行零点和满度的调整,难以达到较高的温度稳定性和长期稳定性.文中描述了采用MSP430F4250单片机和XTR1154-20mA接口芯片构建(4～20)mA压力变送器的设计方案,利用无可调器件的数字化校准技术实现了压力和(4～20)mA输出电流的校准,提高了设备的可靠性和长期稳定性.     

智能化压力变送器——ST3000

霍尼威尔公司研制的新型扩散硅压力变送器 ST—3000装上了八位微处理器、由于采用了数字技术,不仅可以通过计算补偿静压和温度对测量结果的影响,而且能用联接在输出信号线上的对话单元实现变送器的远距离组态、改变量程,查询测量值和诊断故障.     

采用固态传感器技术的硅谐振变送器

在过程控制领域里，在各类控制系统配套的检测仪表中，流量、压力、液位的检测，主要是采用差压、压力变送器（目前虽然各种流量仪表在发展，但孔板等节流装置加差压变送器的检测仪表在实际应用中仍占三分之一以上人随着技术的进步，差压。压力变送器也在不断更新换代，其工作原理也由位移式、力平衡式、扩散硅电阻应变式、电容式而发展成现在采用固态传感器技术和微细加工技术的各种固态化的智能式变送器。本文将结合日本横河公司的硅谐振式的EJA系列变送器进行阐述。固态传感器技术又称物性型传感器技术，它与原来的结构型传感器技术有…     

扩散硅变送器的保护

近年来,全国各制水厂和供水部门逐渐采用半导体压敏元件封装的液位仪和压力变送器(如扩散硅)代替电容式液位仪和动圈式压力变送器。由半导体压敏元件封装制成的压力变送器,体积小、精度高、价格便宜、制作方便,现已被很多小型仪表厂采用和开发生产各档压力变送器和液位仪。从使用情况来看,安装特别方便,无需进行再调整。但是它可靠性较差,容易突然损坏。笔者认为变送器的损坏,除了与电路设计是否合理、元器件的质量优劣有关外,使用地区以及环境对该仪表的可靠性和寿命影响极大。尤其是在南方和多雷雨的山区,这类仪表极易造成突然烧毁和击穿。此外,由于交流电源、继电器开关等高压感应     

A dielectrophoretic chip packaged at wafer level

The paper presents a dielectrophoretic chip, fully enclosed, with bulk silicon electrodes fabricated using wafer-to-wafer bonding techniques and packaged at the wafer level. The silicon electrodes, which are bonded to two glass dies, define in the same time the walls of the microfluidic channel. The device is fabricated from a silicon wafer that is bonded (at wafer level) anodically and using SU8 photoresist between two glass wafers. The first glass die includes drilled holes for inlet/outlet connections while the second glass die assure the electrical connections, through via holes and a metallization layer, between the silicon electrodes and a printing circuit board.     

A 2-D microcantilever array for multiplexed biomolecular analysis

An accurate, rapid, and quantitative method for analyzing variety of biomolecules, such as DNA and proteins, is necessary in many biomedical applications and could help address several scientific issues in molecular biology. Recent experiments have shown that when specific biological reactions occur on one surface of a microcantilever beam, the resulting changes in surface stress deflect the cantilever beam. To exploit this phenomenon for high-throughput label-free biomolecular analysis, we have developed a chip containing a two-dimensional (2-D) array of silicon nitride cantilevers with a thin gold coating on one surface. Integration of microfluid cells on the chip allows for individual functionalization of each cantilever of the array, which is designed to respond specifically to a target analyte. An optical system to readout deflections of multiple cantilevers was also developed. The cantilevers exhibited thermomechanical sensitivity with a standard deviation of seven percent, and were found to fall into two categories-those whose deflections tracked each other in response to external stimuli, and those whose did not due to drift. The best performance of two "tracking" cantilevers showed a maximum difference of 4 nm in their deflections. Although "nontracking" cantilevers exhibited large differences in their drift behavior, an upper bound of their time-dependent drift was determined, which could allow for rapid bioassays. Using the differential deflection signal between tracking cantilevers, immobilization of 25mer thiolated single-stranded DNA (ssDNA) on gold surfaces produced repeatable deflections of 80 nm or so on 0.5-/spl mu/m-thick and 200-/spl mu/m-long cantilevers.     

A dielectrophoretic chip packaged at wafer level

The paper presents a dielectrophoretic chip, fully enclosed, with bulk silicon electrodes fabricated using wafer-to-wafer bonding techniques and packaged at the wafer level. The silicon electrodes, which are bonded to two glass dies, define in the same time the walls of the microfluidic channel. The device is fabricated from a silicon wafer that is bonded (at wafer level) anodically and using SU8 photoresist between two glass wafers. The first glass die includes drilled holes for inlet/outlet connections while the second glass die assure the electrical connections, through via holes and a metallization layer, between the silicon electrodes and a printing circuit board.

     

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.     

一种集成式多参数硅微传感器

为了实现小体积多参数的测量,提出一种单片集成多功能传感器.该传感器包括压力、温度和湿度传感器.各部分分别基于半导体压阻效应、电阻迁移率变化、极板间电容变化为原理制作而成.该传感器采用n型(100)基底,利用体硅和面硅工艺加工而成.测量电阻通过离子注入B 形成扩散电阻.为减小各参数间的相互影响,压力传感器的测量电阻布置于[110]晶向,测温电阻沿[100]晶向布置.温度输出信号可以实现对传感器中压力输出时温度漂移的精确补偿.芯片大小为5mm× 5 mm.试验表明传感器具有良好的线性,小迟滞,较高的灵敏度.     

混合集成力敏传感器的研制

本文对半导体应变式传感器的非线性、温度零漂、灵敏度温度系数、蠕变等参数进行了研究,建立了电子线路综合补偿方法,并采用半导体平面工艺研制成功了小型硅应变片,与混合集成电路技术结合,使敏感元件与补偿、放大电路组合成为一体。     

Stamp-and-stick room-temperature bonding technique for microdevices

Multilayer MEMS and microfluidic designs using diverse materials demand separate fabrication of device components followed by assembly to make the final device. Structural and moving components, labile bio-molecules, fluids and temperature-sensitive materials place special restrictions on the bonding processes that can be used for assembly of MEMS devices. We describe a room temperature "stamp and stick (SAS)" transfer bonding technique for silicon, glass and nitride surfaces using a UV curable adhesive. Alternatively, poly(dimethylsiloxane) (PDMS) can also be used as the adhesive; this is particularly useful for bonding PDMS devices. A thin layer of adhesive is first spun on a flat wafer. This adhesive layer is then selectively transferred to the device chip from the wafer using a stamping process. The device chip can then be aligned and bonded to other chips/wafers. This bonding process is conformal and works even on surfaces with uneven topography. This aspect is especially relevant to microfluidics, where good sealing can be difficult to obtain with channels on uneven surfaces. Burst pressure tests suggest that wafer bonds using the UV curable adhesive could withstand pressures of 700 kPa (7 atmospheres); those with PDMS could withstand 200 to 700 kPa (2-7 atmospheres) depending on the geometry and configuration of the device.     

An analog silicon retina with multichip configuration

The neuromorphic silicon retina is a novel analog very large scale integrated circuit that emulates the structure and the function of the retinal neuronal circuit. We fabricated a neuromorphic silicon retina, in which sample/hold circuits were embedded to generate fluctuation-suppressed outputs in the previous study . The applications of this silicon retina, however, are limited because of a low spatial resolution and computational variability. In this paper, we have fabricated a multichip silicon retina in which the functional network circuits are divided into two chips: the photoreceptor network chip (P chip) and the horizontal cell network chip (H chip). The output images of the P chip are transferred to the H chip with analog voltages through the line-parallel transfer bus. The sample/hold circuits embedded in the P and H chips compensate for the pattern noise generated on the circuits, including the analog communication pathway. Using the multichip silicon retina together with an off-chip differential amplifier, spatial filtering of the image with an odd- and an even-symmetric orientation selective receptive fields was carried out in real time. The analog data transfer method in the present multichip silicon retina is useful to design analog neuromorphic multichip systems that mimic the hierarchical structure of neuronal networks in the visual system.     

差分电容硅微加速度计检测电路研究

针对硅微加速度计中微小差分电容检测,提出了一种基于调制解调方法的闭环检测电路,介绍了该闭环检测系统的原理框图和实现途径。分析了基于单路载波的前置电容-电压( C-V)转换电路,证明了基于相关芯片的解调方法的有效性,其解调效率仅对开环输出有影响;基于双路反馈电路的静电力平衡回路有效提高该检测系统的线性度。结合硅微加速度计参数和电路设计参数,对加速度计系统进行了仿真,仿真结果显示系统稳定,刻度系数为0.9 V/gn 左右,带宽700 Hz左右。结合表头进行的精密转台实验结果表明该加速度计系统刻度系数0.88 V/gn,量程可达±13 gn。     

An improved bulk acoustic waves chip based on a PDMS bonding layer for high-efficient particle enrichment

In this work, we developed a feasible way to package bulk acoustic waves chip with sandwich structure by inserting a polydimethylsiloxane (PDMS) layer as the adhesive between cover glass and silicon substrate. After spin-coating and curing process, a PDMS layer was formed on one side of the cover glass and then bonded to the silicon substrate with microchannels by oxygen plasma treating. Both simulation and experiment showed that the chip was not leaking and the acoustic waves produced by the piezoelectric transducer could be propagated through the PDMS layer. Finally, a standing wave field was formed in the microchannels. Compared with traditional chip bonded by anodic bonding, simulation results showed that this packaging method did decrease the acoustic pressure in the channel, but the reduction was acceptable. After optimizing the experimental parameters, we successfully aggregated 15-μm silica spheres under a very low input power (21 dBm) at a flow velocity of 1 ml/h, and the enrichment efficiency of silica spheres was greater than 97%.