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A four-bit digital microinjector using microheater array for adjusting the ejected droplet volume 总被引:1,自引:0,他引:1
Tae Goo Kang Young-Ho Cho 《Journal of microelectromechanical systems》2005,14(5):1031-1038
In this paper, we present the design, fabrication, and experimental results of 4-bit digital microinjectors, whose ejected droplet volumes are adjusted by the digital operation of a 4-bit microheater array. We design the reference microinjectors as well as its comparative test structures. In the fabrication process, we use a five-mask micromachining process and the total chip size of the fabricated microinjector is 7640 /spl mu/m/spl times/5260 /spl mu/m. We observe the microbubble generation and collapse on the microheater array. The microbubbles initiate and grow individually on top of each operating microheater, however the microbubbles merge together before collapse. We measure the ejected droplet volumes and velocities, which are adjusted from 12.1 /spl ap/ 55.6 pl and 2.3 /spl ap/ 15.7m/s, respectively, depending on the 15 possible combinations of 4-bit microheater array. We also experimentally characterize the effect of geometric variation including the microheater size, intermicroheater gap, microchannel width and sequential operation of microheater array on the ejected droplet volume and velocity. Thus, the present microinjector has a potential for application to the high-resolution inkjet printers with multiple gray levels or high-precision fluid injectors with variable volume control. 相似文献
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One of the important design criteria of micropropulsion systems in particular VLM is the type of microheater, its layout and placement with a view to achieve uniform heating of propellant, fast heat transfer efficiency with minimum input power. Thrust produced by microthruster not only depends on the structural geometry of the thruster and propellant flow rate, but also on the chamber temperature to produce super saturated dry stream at the exit nozzle. Detailed design of microheater in thermal and electrical domains using co-solvers available in MEMS software tools along with material’s thermal property, temperature dependence of electrical resistivity and thermal conductivity have been considered in the present work to achieve precise modeling and experimental accuracy of heater operation. The chamber temperature was analytically calculated and subsequently the required resistance and power were estimated. The boron diffused microheaters of meanderline configuration in silicon substrate has been designed and its finite element based electro-thermal modeling was employed to predict the heater characteristics. The variation of microheater temperature with time, applied voltage and along chamber length has been determined from the modeling. Subsequently the designed microheater was realized on silicon wafer by lithography and boron diffusion process and its detailed testing was evaluated. It was found that boron diffused resistor of 820 Ω can generate 405 K temperature with applied input power 2.4 W. Finally the simulated results were validated by experimental data. 相似文献
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Coppola G. Striano V. Ferraro P. De Nicola S. Finizio A. Pierattini G. Maccagnani P. 《Journal of microelectromechanical systems》2007,16(3):659-667
This paper describes the possibility of employing a digital holographic microscope (DHM) to carry out a noncontact and nondestructive characterization of a microheater integrated on a silicon nitride membrane and subjected to a high thermal load. Microheaters can be affected by the presence of the residual stress due to the technological processes appearing in the form of undesired bowing of the membrane. Moreover, when the temperature of the microheater increases, a further warpage of the structure can be induced. A DHM allows for evaluation, with high accuracy, the deformations due to the residual stress and how these deformations are affected by the thermal loads due to the microheater operating mode. In particular, this dynamic analysis is made possible by measuring the unwanted longitudinal displacement induced by the thermal expansion of both the device and its mechanical support. Taking into account this displacement, it is possible to have a continuous monitoring of profile deformation induced by the working condition of the microheater. 相似文献
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Biplob Mondal Santanu Maity Sonali Das Dipankar Panda Hiranmay Saha Avra Kundu 《Microsystem Technologies》2016,22(12):2757-2764
Thin films of metal-oxide with integrated microheater on micromachined silicon substrate have attracted great deal of interest towards the development of extremely small and highly sensitive gas sensor. Fabrication of MEMS microheater which is the key component for the development of low power gas sensor is reported here. The microheater is fabricated in a novel co planer fashion where the heating element and the inter-digitated electrode are place side by side. The fabricated device is structurally and electrically characterized by SEM and I–V measurements. Using ZnO–SnO2 composite material, hydrogen sensor was constructed on the microheater platform. A suitable package for encapsulating the fabricated device is designed and the device was successfully mounted on it. The sensing behavior of the packaged sensor is performed by exposing the sensor to hydrogen. 相似文献
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P. Ivanov J. Laconte J. P. Raskin M. Stankova E. Sotter E. Llobet X. Vilanova D. Flandre X. Correig 《Microsystem Technologies》2005,12(1-2):160-168
In this paper, a Silicon-On-Insulator (SOI) solid-state gas-sensor with an original design of a polysilicon loop-shaped microheater fabricated on a thin-stacked dielectric membrane is presented. The microheater ensures high thermal uniformity and very low power consumption (25 mW for heating at 400°C). Sensitive films are based on tin and tungsten oxides deposited either by RF sputtering or drop coating methods. The fabricated sensors are tested to a wide variety of contaminant species and promising results are obtained. The use of completely CMOS compatible TMAH-based bulk micro-machining techniques during the fabrication process, allows easy smart gas sensor integration in SOI-CMOS technology. This makes SOI-based gas-sensing devices particularly attractive for use in handheld battery-operated gas monitors. 相似文献
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Cheng Y.-T. Wan-Tai Hsu Najafi K. Nguyen C.T.-C. Liwei Lin 《Journal of microelectromechanical systems》2002,11(5):556-565
A glass vacuum package based on localized aluminum/silicon-to-glass bonding has been successfully demonstrated. A constant heat flux model shows that heating can be confined locally in the dielectric layer underneath a microheater as long as the width of the microheater and the thickness of silicon substrate are much smaller than the die size and a good heat sink is placed underneath the silicon substrate. With 3.4 W heating power, /spl sim/0.2 MPa applied contact pressure and 90 min wait time before bonding, vacuum encapsulation at 25 mtorr (/spl sim/3.33 Pa) can be achieved. Folded-beam comb drive /spl mu/-resonators are encapsulated and used as pressure monitors. Long-term testing of vacuum-packaged p-resonators with a Quality Factor (Q) of 2500 has demonstrated stable operation after 69 weeks. A /spl mu/-resonator with a Q factor of /spl sim/9600 has been vacuum encapsulated and shown to be stable after 56 weeks. 相似文献
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Li Xingchen Huang Yiyong Chen Xiaoqian Xu Xiangming Xiao Dingbang 《Microsystem Technologies》2018,24(5):2409-2417
Microsystem Technologies - A multilayer thin film aluminum/titanium (Al/Ti) microheater is developed for the microthruster liquid propellant vaporizing and gas heating for increasing the specific... 相似文献
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The size of microfluidic channels prevents the use of conventional methods for flow velocity measurement. This paper presents
and evaluates a method of flow velocity measurement using a temperature dependent fluorescent dye and a microheater. The microheater
applied a heat pulse to the dye flowing in a glass capillary, resulting in a plug of fluid of lower fluorescent intensity.
By tracking this low intensity region, the velocity of the heat pulse travelling with the flow was determined and used to
calculate average flow velocity using correlations. The method was verified by measuring a range of flow velocities in two
different sized glass capillaries. 相似文献
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考虑到基于二次曲线这种几何基元的摄像机标定方法比基于点或直线的方法具有更好的鲁棒性,给出了一种新的基于共面圆的摄像机标定方法。该方法的主要特点是模板形式简单、易于制作,仅需任意分布的三个或三个以上共面圆,且不需要进行圆环定位;不需要模板与图像之间的匹配;也无需求解任何非线性方程组。从几何角度对算法进行形象描述,并从代数的角度给出了严格论证。模拟和真实图像实验表明,该算法精确度高,鲁棒性强,表现出了十分良好的实用性。 相似文献
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Tiwari Shailendra Kumar Bhat Somashekara Mahato Krishna K. 《Microsystem Technologies》2018,24(8):3273-3281
Microsystem Technologies - This paper presents the design and fabrication of a low-cost series microheater which works on the principle of Joule heating. The conducting silver-ink (LOCTITE ECI 1010... 相似文献
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This paper describes the microfocusing in a microchannel using the thermal actuation of a pair of microbubbles. A microbubble
was produced from de-ionized (DI) water with an integrated microheater, and the volume was controlled by applying voltage.
The microfocusing was demonstrated with a polydimethylsiloxane (PDMS) device consisting of two layers. The top layer included
a microchannel that was 300 μm wide and 50 μm high. It was flanked by a pair of reservoirs. The bottom layer provided a microheater
underneath the reservoir. Upon heating, DI water boiled immediately over the microheater and formed a microbubble that came
out of the reservoir in a perpendicular direction toward the fluid. The fluid was focused from 300 to 22 μm, as the distance
between the apexes of the arch-shaped microbubbles was shortened due to expansion, which was maintained at a flow velocity
up to approximately 17.8 mm s−1. The temperature of the water in the reservoir was estimated to reach the boiling point within 62 or 160 ms, depending on
the substrate. 相似文献
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I. Hotovy V. Rehacek F. Mika T. Lalinsky S. Hascik G. Vanko M. Drzik 《Microsystem Technologies》2008,14(4-5):629-635
This work describes the design, simulation, fabrication and characterization of a TiN/Pt microheater prepared on a GaAs micromechanical
structure as a prospective device for micro-electro-mechanical system (MEMS) sensor arrays. Electro-thermal simulation was
employed to verify the properties of the designed microstructure, which confirmed achievement of the operating temperatures
in the range from 470 to 600 K with a heating power less than 25 mW. The average temperature gradient in the active area does
not exceed 0.6 K/μm. Fabrication of GaAs suspended membranes was demonstrated, realized in two steps by combination of surface
and bulk micromachining. Development and characterization of a microheater on a GaAs membrane is described. The mechanical
stability of the heated multilayer membrane structure was tested and satisfactory mechanical stability of the hotplate was
confirmed. The power consumption at an operating temperature of approximately 550 K is about 30 mW which is in good agreement
with the value of about 22 mW obtained from electro-thermal simulation. The achieved thermal resistance value is 8.43 K/mW. 相似文献
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This paper reports a low power miniaturized MEMS based integrated gas sensor with 36.84 % sensitivity (ΔR/R0) for as low as 4 ppm (NH3) gas concentration. Micro-heater based gas sensor device presented here consumes very low power (360 °C at 98 mW/mm2) with platinum (Pt) micro-heater. Low powered micro-heater is an essential component of the metal oxide based gas sensors which are portable and battery operated. These micro-heaters usually cover less than 5 % of the gas sensor chip area but they need to be thermally isolated from substrate, to reduce thermal losses. This paper elaborates on design aspects of micro fabricated low power gas sensor which includes ‘membrane design’ below the microheater; the ‘cavity-to-active area ratio’; effect of silicon thickness below the silicon dioxide membrane; etc. using FEM simulations and experimentation. The key issues pertaining to process modules like fragile wafer handling after bulk micro-machining; lift-off of platinum and sensing films for the realization of heater, inter-digitated-electrodes (IDE) and sensing film are dealt with in detail. Low power platinum microheater achieving 700 °C at 267 mW/mm2 are fabricated. Temperature calculations are based on experimentally calculated thermal coefficient of resistance (TCR) and IR imaging. Temperature uniformity and localized heating is verified with infrared imaging. Reliability tests of the heater device show their ruggedness and repeatability. Stable heater temperature with standard deviation (σ) of 0.015 obtained during continuous powering for an hour. Cyclic ON–OFF test on the device indicate the ruggedness of the micro-heater. High sensitivity of the device for was observed for ammonia (NH3), resulting in 40 % response for ~4 ppm gas concentration at 230 °C operating temperature. 相似文献
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基于共面靶标双目立体视觉传感器标定 总被引:1,自引:0,他引:1
根据双目立体视觉传感器的特点,提出了一种基于共面靶标的双目立体视觉传感器的标定方法.在不需要外部测量设备的情况下,通过共面靶标在平面上自由移动,获得靶标的标定点图像坐标,利用类似于Dr.Janne Heikkil(a)和Dr.Olli Silven所提出来的摄像机内部参数标定模型,采用线性和非线性结合的方法对双目摄像机进行摄像机内部参数的标定.试验结果表明,标定参数与出厂参数有一定的差异,但和实际情况还是吻合的,并且标定方法操作简便,切实可行. 相似文献
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An elevated coupled coplanar waveguide is proposed and analyzed with a view to exploit the advantage of miniaturization that is possible with elevated coplanar waveguide structures. The influence of elevation on the directional characteristics of the elevated coupled coplanar waveguide has also been studied. The proposed structure is analyzed using a modified universal matrices finite element method. © 1996 John Wiley & Sons, Inc. 相似文献
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基于摄像机的正交运动对摄像机进行标定是基于主动视觉摄像机标定的一种重要方法. 一般来说, 5组这样的正交运动就可以线性标定摄像机的5个内参数. 然而, 关于这5组摄像机运动应满足什么条件才可以保证所产生的5个线性约束方程是独立的, 文献中对这个问题至今没有定论. 一种流行的猜测是只要这5组正交运动下的平移向量任意3个不共面, 则对应的5个摄像机内参数约束方程必然独立. 本文对这个问题进行了进一步讨论, 证明了当5组正交运动中其中的3组构成一个三正交运动时, 此时尽管构成5组正交运动的7个平移向量没有任意3个共面, 但产生的5个约束方程却可能不独立, 并给出了一个不独立的具体例子. 相似文献
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Jiunn-Jye Chang 《国际射频与微波计算机辅助工程杂志》1996,6(3):166-173
In this article, for asymmetrical coplanar waveguides with anisotropic substrates, the analytical dispersion formulas for effective dielectric constant ϵeff are first derived and then used to study the frequency-dependent characteristics ϵeff(f). The errors in the dispersion formulas are less than 2% when compared with the available results. In addition, based on the derived dispersion formulas and the Fourier transform, the effects of signal dispersion are studied for a Gaussian pulse propagating on an asymmetrical coplanar waveguide with anisotropic substrate. © 1996 John Wiley & Sons, Inc. 相似文献