共查询到20条相似文献,搜索用时 343 毫秒
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为了避免微加速度计在工作过程中因为共振导致结构损坏,需要在结构中合理设计阻尼.设计了一个复合量程压阻式微加速度计,为了使结构中各个传感器具有较好的阻尼参数,通过静电键合在硅结构层下制作一玻璃层.根据Reynolds方程,可知当硅-玻璃静电键合间距d=2.25μm时,复合量程微加速度计中各个传感器可得到较好的阻尼比. 相似文献
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针对电容式微加速度计的刻度温漂,根据微加速度计的检测原理及热变形的分析结果,建立了刻度温漂的半解析模型,并在此基础上分析了刻度温漂的主要影响因素.分析结果表明,刻度温漂由两部分组成,第一部分主要由单晶硅的弹性模量的温度系数决定,可以通过高掺杂降低;第二部分由微加速度计的热变形引起,它的大小与封装胶的弹性模量、梳齿的宽度、大电容间隙与小电容间隙的比值以及固定梳齿锚点的位置相关;第一部分和第二部分分别是正数和负数,因此相互补偿.基于MEMS体硅微加工工艺,制造了微加速度计的实验样品,刻度温漂的测量结果验证了理论分析结果的正确性. 相似文献
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本文针对硅微机械结构振动幅度由于封装难以计算机视觉测量及电学测量中的精度受接口电路参数影响的问题,在对静电梳齿驱动、平板电容检测的硅微谐振结构进行建模分析后,提出基于单边带电压比的电学测量振动幅度的方法并分析了测量方法的原理。实验表明研制的某硅微机械谐振加速度计在受迫振动下的振动幅度为0.25um,频谱分析还表明存在上电噪声引起的振动幅度,该测试方法还能应用于硅微谐振结构的谐振频率测量,同时为高品质因数的硅微机械谐振结构的可静电自激驱动提供了依据。 相似文献
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封装热应力是导致MEMS器件失效的主要原因之一,本文设计了一种MEMS高g加速度传感器,并仿真研究了传感器在封装过程中的热应力及影响其大小的因素。根据封装工艺,建立设计的高g加速度传感器封装的有限元模型,利用AN-SYS软件仿真传感器在不同的贴片工艺中受到的热应力及影响热应力的因素。结果显示,在封装中,与直接贴片到管壳底部相比,MEMS高g加速度传感器芯片底面键合高硼硅玻璃后再贴片到管壳底部时,封装热应力可从135MPa降低到33MPa;在贴片工艺中,基板的热膨胀系数和贴片胶的弹性模量、热膨胀系数及厚度是影响封装热应力的主要因素;在健合工艺中,基板和键合温度主要影响到热应力的大小。 相似文献
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针对硅微陀螺的零偏受环境温度影响比较敏感的问题,研究了一种新的温度补偿方案。通过研究驱动频率的温度特性,发现驱动频率与温度之间存在很好的线性关系,经过适当的标定,驱动频率可以作为内置温度传感器取代传统的温度传感器,解决了传统传感器温度不准确和测量滞后的问题。建立了驱动频率与零偏的模型,对硅微陀螺的零偏进行了温度补偿验证。验证试验表明,在-40℃~60℃全温区范围内,零偏温度灵敏度由0.053°/(s.℃)提高到0.00244°/(s.℃),有效地改善了全温区的零偏温度系数。 相似文献
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Jihperng Leu Chin‐Cheng Chang Alexander Chen Mao‐Hsing Lin Kun‐Feng Huang 《Journal of the Society for Information Display》2012,20(1):28-36
Abstract— Mura defects become visible in a 13.3‐in. TFT‐LCD using chip‐on‐glass (COG) packaging when the thickness of the glass substrate is decreased from 0.5 to 0.3 mm. Mura, the non‐uniform brightness in LCDs, is caused by COG packaging due to the mismatch of the coefficient of thermal expansion (CTE) and Young's modulus between the glass substrate and the IC‐driver Si chips. In this paper, a 3‐D finite‐element‐analysis (FEA) model, coupled with transient thermal analysis is first established to examine the warpage and stress behavior in the upper‐glass‐plate post‐COG‐package processing for identifying the root causes of the light‐leakage phenomenon. Prior to that, the simulated warpage results are validated by surface‐contour measurement. Data and modeling results show that a low bonding temperature together with a low modulus in novel ACF materials can effectively eliminate Mura. Besides, thinner silicon or a shorter length of Si chips as drivers offers enhanced reduction in the localized warpage, and thus can be a practical and low‐cost solution for eliminating mura defects. 相似文献
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Thermal drift analysis using a multiphysics model of bulk silicon MEMS capacitive accelerometer 总被引:1,自引:0,他引:1
Gang Dai Mei LiXiaoping He Lianming DuBeibei Shao Wei Su 《Sensors and actuators. A, Physical》2011,172(2):369-378
An interpretation of the thermal drift of the bulk silicon MEMS capacitive accelerometer using multiphysics analysis is proposed in this paper. Stress, strain, electrostatics, thermal and structural interactions are simulated based on the finite element method. The thermal drift is generated by both the stiffness asymmetry of the U-springs of the structure and relative displacement caused by the mismatch in thermal expansion coefficients between the Pyrex glass substrate and heavily boron-doped silicon structure, neither of which is dispensable. Although the layout design is symmetrical, the asymmetric widths of the U-springs, which cause stiffness asymmetry, are observed by scanning electron microscopy. To achieve a fast and feasible simulation, we divide the model into two components with different configurations. During the simulation, boundary conditions are carefully set up according to the fabrication process. A series of experiments is designed to verify the result, including a temperature experiment from −40 to 100 °C and DC voltage polarity experiment. To verify the conclusion, a new layout design that gradually increases the width of the U-springs without changing any other dimension is simulated, fabricated, and tested. The simulation and experiment results are compared and discussed. 相似文献
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In the present work, the design of a micromachined thermal accelerometer based on convection effect was studied. The accelerometer sensitivity and especially the frequency response have been experimentally and numerically studied with low cavity volume. Although this type of sensor has already been intensively examined, few information concerning the frequency response modeling is currently available. In particular, no experimental result about frequency response for low volume and their variation according to the external temperature variation was reported in the literature. In certain particular condition, we assumed that a bandwidth of 120 Hz at −3 dB has been measured.By using numerical resolution of fluid dynamics equations with the computational fluid dynamics (CFD) software package Fluent V6.2 and a simple model based on thermo-conduction, a good accordance with the experimental results has been demonstrated. So, the effects of these two parameters like the volume and the external temperature variation on the thermal accelerometer response have been theoretically, experimentally and numerically investigated. 相似文献