A novel thermal-bubble-based micromachined accelerometer

Liao, Ke-Min; Chen, Rongshun; Chou, Bruce

doi:10.1016/j.sna.2006.02.049

Cited by 43 publications

(37 citation statements)

References 13 publications

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“…However, on liquid inclinometers few papers present results but no study indicating a model has been published [7][8]. As a function of temperature, the laws of variations on the specific properties of liquids do not follow the same ones as those of gases.…”

Section: With H Convection Coefficientmentioning

confidence: 98%

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Micromachined inclinometer based on fluid convection

Crespy

Courteaud

Combette

et al. 2008

2008 Symposium on Design, Test, Integration and Packaging of MEMS/MOEMS

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r' I""" r-g,slf(8') Fig. 1. The sensor principle.Abstract-This paper presents the experimental and theoretical study of an inclinometer based on heat exchange. The principle of the sensor is composed of a resistance heater placed between two detectors and suspended in a cavity fiUed with fluid. In this study, several fluids such as liquid or gaseous, were used. The temperature gradient and sensitivity as a function of fluid were studied by using the numerical resolution of equations of fluid dynamics with the Computational Fluid Dynamics (CFD) software Fluent V6.2. We showed that the sensitivity of the "liquid sensors" is greater than "gas sensors" one. The experimental measurements corroborate with numerical simulation. In addition, we have demonstrated that the sensitivity of the sensor is proportional to the Rayleigh number which is characteristic of the natural convection flow.

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Section: With H Convection Coefficientmentioning

confidence: 98%

“…The experimental study of all of these properties is p2.p.C not achievable and therefore dimensional analysis is used to Ra = Pr .Gr = g.13 .IiT. p (8) group the parameters that influence a convection Il.A phenomenon.…”

Section: With H Convection Coefficientmentioning

confidence: 99%

Micromachined inclinometer based on fluid convection

Crespy

Courteaud

Combette

et al. 2008

2008 Symposium on Design, Test, Integration and Packaging of MEMS/MOEMS

View full text Add to dashboard Cite

show abstract

“…(1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17) Some are made using thermal convection technologies, and their chambers may be filled with air, CO 2 , or liquids. It was reported that the sensitivity of an inclinometer can be increased by using a nonfloating-type structure on a flexible substrate without fabricating the conventional cavities of floating-type silicon-based devices.…”

Section: Introductionmentioning

confidence: 99%

Wireless Inertial Sensors Made on Flexible Substrates and Based on Thermal Convection and Near-Field-Communication Principles

2016

Sensors and Materials

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In this study, several kinds of wireless inertial sensors, such as accelerometers, angular accelerometers and inclinometers based on the thermal convection principle, were integrated with near-field-communication (NFC) antennas and made on a flexible substrate so that the devices can become wireless sensors. The reason to apply a flexible substrate instead of the traditional silicon was to reduce the power leaked through the flexible substrate, because the thermal conductivity of silicon is 0.06-0.0017 W/(cm·K), which is 25 times larger than that of the flexible substrate, 1.48 W/(cm·K). Another key goal was to fabricate the nonfloating-type devices without making a cavity on the substrate, so that the new devices would be easier to fabricate and more reliable than the previous floating-type; in which the components of heaters and thermal sensors lay over the cavity on the silicon substrate. Also inert Xe gas was used to fill the chamber instead of the previously used CO 2 or air, so that the oxidization problem of the thermal sensors caused by the heater can be eliminated. On the other hand, one can fabricate the components of heaters and thermal sensors on the flexible substrate directly or stack them on a layer of aluminum nitride and then use some packages with hemispherical or hemicylindrical chambers instead of rectangular ones. The sensitivities were analyzed and compared with those of the previous sensors to prove the feasibility of these novel ideas.

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“…Conventional accelerometers are fabricated on silicon wafers, (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17) and some of them are fabricated using thermal bubble technologies and a chamber is filled with air, CO 2 , liquid, or others. As shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

“…The second idea is to form the device on a flexible substrate, such as plastic or polyimide; the thermal conductivity of plastic [0.06-0.0017 W/(cm·K)] is about twenty-fifth that of silicon [1.48 W/(cm·K)]; thus, we can save more power by preventing leakage through the substrate. The third idea is to fill the chamber with xenon gas for heat conduction instead of CO 2 previously used, which can oxidize the heater and thermal sensors, (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) while the xenon gas cannot. Therefore, we can increase heater reliability and life cycle.…”

Section: Introductionmentioning

confidence: 99%

Novel Wireless Thermal Convection Angular Accelerometer Integrated with Radio Frequency Identification Tag

2013

Sensors and Materials

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Five novel ideas are proposed to integrate a radio frequency identification (RFID) tag with a thermal convection angular accelerometer on a flexible substrate. The first idea is that this device has no movable parts; therefore, it is very reliable. The second idea is that the thermal conductivity of flexible substrates, such as plastic or polyimide, is much lower than that of silicon, and thus, it can save more power and is very useful for mobile operations. The third new idea is to apply xenon gas to the chamber to conduct heat instead of CO 2 conventionally used, which can oxidize the heater and thermal sensors, while the inert gas xenon cannot. The fourth new idea is the use of a hemispherical chamber; it is more streamlined with less drag to yield quicker responses. The fifth new idea is to integrate an angular accelerometer with the RFID tag on the same flexible substrate; thus, the device becomes a more useful wireless sensor. Compared with a device fabricated using a rectangular chamber filled with CO 2 , we noted that the linearity, sensitivity, and response time of step-input angular acceleration are better for the proposed device. The sensitivity is 71.4 °C/(rad/s 2 ) and the response time is 60 μs.

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A novel thermal-bubble-based micromachined accelerometer

Cited by 43 publications

References 13 publications

Micromachined inclinometer based on fluid convection

Micromachined inclinometer based on fluid convection

Wireless Inertial Sensors Made on Flexible Substrates and Based on Thermal Convection and Near-Field-Communication Principles

Novel Wireless Thermal Convection Angular Accelerometer Integrated with Radio Frequency Identification Tag

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