A novel inertial switch based on nonlinear-spring shock stop

Deng, Kangfa; Su, Weiguo; Li, S.; Zhang, Yuanhui; Chen, G. Z.; Zhang, W.; Wan, Shu Min; Li, L.; Jiang, Shoubo; Zheng, Haowen; Xia, Wei

doi:10.1109/transducers.2013.6627285

Cited by 4 publications

(1 citation statement)

References 9 publications

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“…In order to facilitate the signal processing and enhance the contact effect, Wang et al designed a laterally-driven inertial microswitch using two cantilever beams as the fixed electrode, which can reduce the contact-bouncing effect and prolong the contact time [14]. Then, Qihuan Zhang et al reported a laterally-driven inertial microswitch with the double-stair shape flexible cantilever beam as the movable electrode for prolonging the contact time [15]. Deng et al designed the inertial microswitch with double flexible electrodes based on the silicon bulk micromachining process, which can further improve the contact effect [16].…”

Section: Introductionmentioning

confidence: 99%

Design and Optimization of a Stationary Electrode in a Vertically-Driven MEMS Inertial Switch for Extending Contact Duration

Yang

et al. 2017

Sensors

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A novel micro-electro-mechanical systems (MEMS) inertial microswitch with a flexible contact-enhanced structure to extend the contact duration has been proposed in the present work. In order to investigate the stiffness k of the stationary electrodes, the stationary electrodes with different shapes, thickness h, width b, and length l were designed, analyzed, and simulated using ANSYS software. Both the analytical and the simulated results indicate that the stiffness k increases with thickness h and width b, while decreasing with an increase of length l, and it is related to the shape. The inertial micro-switches with different kinds of stationary electrodes were simulated using ANSYS software and fabricated using surface micromachining technology. The dynamic simulation indicates that the contact time will decrease with the increase of thickness h and width b, but increase with the length l, and it is related to the shape. As a result, the contact time decreases with the stiffness k of the stationary electrode. Furthermore, the simulated results reveal that the stiffness k changes more rapidly with h and l compared to b. However, overlarge dimension of the whole microswitch is contradicted with small footprint area expectation in the structure design. Therefore, it is unreasonable to extend the contact duration by increasing the length l excessively. Thus, the best and most convenient way to prolong the contact time is to reduce the thickness h of the stationary electrode while keeping the plane geometric structure of the inertial micro-switch unchanged. Finally, the fabricated micro-switches with different shapes of stationary electrodes have been evaluated by a standard dropping hammer system. The test maximum contact time under 288 g acceleration can reach 125 µs. It is shown that the test results are in accordance with the simulated results. The conclusions obtained in this work can provide guidance for the future design and fabrication of inertial microswitches.

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Section: Introductionmentioning

confidence: 99%

Design and Optimization of a Stationary Electrode in a Vertically-Driven MEMS Inertial Switch for Extending Contact Duration

Yang

et al. 2017

Sensors

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Electrical contact performance of MEMS acceleration switch fabricated by UV-LIGA technology

et al. 2015

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telecommunication, radar, RF and defense systems, etc. (Li et al. 2012;Kim et al. 2012). In particular, MEMS acceleration switches can respond rapidly in specific applications without power consumption. For instance, Wang et al. (2013) developed a low-G horizontally-sensitive inertial micro-switch which switches on when an acceleration threshold is met. Fu et al. (2013) presented a novel MEMS inertial switch used for power management, which can be integrated with detection and control systems without power consumption. Deng et al. (2013) reported an inertial micro-switch based on nonlinear-spring shock stopper which can reduce contact bouncing. Ma (2013) and Kim et al. (2013) also designed several inertial switches which are capable to adjust the acceleration threshold.Electrical contact performance is one of three key parameters of the MEMS acceleration switch (The other two are response time and contact reliability respectively) (Zhou et al. 2013). Contact resistance plays a key role in electrical performance and depends on sample material, contact pressure, temperature, structure design, surface cleanliness, roughness and flatness (Zhou et al. 2013). Greenwood, et al. (1966 put forward a classic theory of elastic contact, which introduced an item named 'elastic contact hardness', a composite quantity depending on the material properties and surface topography. Li et al. (2012) presented an electrical contact resistance model and pointed out that the contact resistance is a function of contact load. Jensen et al. (2005) explored contact heating in the RF MEMS switch and demonstrated that it can reduce the contact resistance significantly. In addition, mechanical cycling would increase the contact resistance because of the insulating film on surface. Broue et al. (2010) proposed a new method to investigate the micro-scale contact mechanism and indicated that the material is a key issue of contact resistance. Jackson et al. (2012) presented the multipleAbstract This paper expanded a micro-contact resistance model to investigate the contact performance for a acceleration switch fabricated by UV-LIGA (Ultra-violet Lithographie, Galvanoformung and Abformung) technology. Based on the relationship between the contact radius a and electron mean free path λ, three different contact resistance models have been analyzed. The material properties (elastic modulus E, hardness H and Poisson's ratio v) and surface topographic parameters (asperity summit radius r, standard deviation of height distribution σ, and surface density of asperity) have been studied to evaluate the contact resistance-load characteristics. The results show that the theoretical prediction of contact resistance-load characteristics correlates well with the experimental results except there exists experimental discrepancy. The discrepancy between theoretical predictions and experimental results mainly is due to the contaminations, errors from assumptions, surface oxidation and external environmental conditions.

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A review of MEMS inertial switches

Cao

Zhang

2019

Microsyst Technol

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A novel inertial switch based on nonlinear-spring shock stop

Cited by 4 publications

References 9 publications

Design and Optimization of a Stationary Electrode in a Vertically-Driven MEMS Inertial Switch for Extending Contact Duration

Design and Optimization of a Stationary Electrode in a Vertically-Driven MEMS Inertial Switch for Extending Contact Duration

Electrical contact performance of MEMS acceleration switch fabricated by UV-LIGA technology

A review of MEMS inertial switches

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