Mechanical latching stops for reliability improvement of MEMS in shock environments

Xu, Kaisi; Zhang, Wei

doi:10.1007/s00542-018-3714-8

Cited by 8 publications

(7 citation statements)

References 31 publications

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“…The latch with a curved or angled surface is stiff in the sensitive direction of the switch and compliant in the direction perpendicular to the sensitive direction, enabling the switch to remain closed after the end of an acceleration event. Xu et al [32] studied the energy dissipation of the latching process and concluded that the latches can greatly enhance the shock robustness of the switch compared with hard stops. Ma et al [33] used various polydimethylsiloxane (PDMS) caps to change the displacement state of the proof mass, thus enabling the adjustment of the acceleration threshold from 40 g to 75 g. Guo et al [34,35] designed the switch with multi-contacts independent to the proof-mass to prevent the contacts from the impact resulting from the rebound or vibration of the proof-mass once the switch was latched, and therefore the contact reliability was improved.…”

Section: Persistent Closed Inertial Micro-switchesmentioning

confidence: 99%

Recent Advancements in Inertial Micro-Switches

et al. 2019

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Inertial micro-switches have great potential in the applications of acceleration sensing, due to the integrated advantages of a small size, high integration level, and low or even no power consumption. This paper presents an overview of the recent advancements made in research on the sensitive direction, threshold acceleration, contact effect, and threshold accuracy of inertial micro-switches. The reviewed switches were categorized according to the performance parameters, including multi-directional switches, multi-threshold switches, persistent closed switches, flexible-electrode switches, and low-g high-threshold-accuracy switches. The current challenges and prospects are also discussed.

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Section: Persistent Closed Inertial Micro-switchesmentioning

confidence: 99%

Recent Advancements in Inertial Micro-Switches

et al. 2019

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“…Kaisi Xu et al [88,89] reported a stopper based on the latch structure in 2016 and 2018, which can protect the structure from damage by self-locking under shock loads. The latching structure proposed in this study can reduce about 2/3 of the structural impact (as shown in Figures 8 and 9).…”

Section: Latch Mechanismsmentioning

confidence: 99%

Reliability of MEMS in Shock Environments: 2000–2020

Peng

You

2021

Micromachines

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The reliability of MEMS in shock environments is a complex area which involves structural dynamics, fracture mechanics, and system reliability theory etc. With growth in the use of MEMS in automotive, IoT, aerospace and other harsh environments, there is a need for an in-depth understanding of the reliability of MEMS in shock environments. Despite the contributions of many articles that have overviewed the reliability of MEMS panoramically, a review paper that specifically focuses on the reliability research of MEMS in shock environments is, to date, absent. This paper reviews studies which examine the reliability of MEMS in shock environments from 2000 to 2020 in six sub-areas, which are: (i) response model of microstructure, (ii) shock experimental progresses, (iii) shock resistant microstructures, (iv) reliability quantification models of microstructure, (v) electronics-system-level reliability, and (vi) the coupling phenomenon of shock with other factors. This paper fills the gap around overviews of MEMS reliability in shock environments. Through the framework of these six sub-areas, we propose some directions potentially worthy of attention for future research.

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“…This enables high sensitivity of the inertial switch to the inertial force for operation and high robustness in fabrication, for example, etching. The compliance design of the switch contacts, based on our previous works [3, 8], guarantees sufficient contact time for operation and provides secondary‐shock protection for instantaneous impact between electrodes. Each pair of stoppers includes an embedded cylindrical one (through the proof mass) and an exterior perimeter one (in the corner of the substrate).…”

Section: Design and Simulationmentioning

confidence: 99%

“…Loaded with the periodic vibration (0.6 g, 40 Hz), the gravity‐compensated inertial switch achieves simulated contact time of 75 μs and simulated coefficient of restitution of 0.3. This contact time is acceptably long compared with that of a hard impact (approximately 5 μs); and this coefficient of restitution is less than half of that of silicon‐silicon impact (0.7) [8].…”

Section: Design and Simulationmentioning

confidence: 99%

Micromachined inertial switch for sub‐g monitoring using gravity‐based threshold compensation

You

Ruan

2020

Electronics Letters

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This letter presents the original design of a microelectromechanical systems inertial switch with ultra‐low threshold (∼0.6 g) and great potential for batch manufacturing. The gravity is utilized to narrow the gap between electrodes during operation, defined here as threshold compensation. This lightens the fabrication burden, enabling the device to be made by standard silicon‐on‐glass micromachining without excessive optimization. Finite element analysis has been conducted to demonstrate positive effects of gravity involvement (9.4 μm reduction of the gap) and compliance design of the movable electrodes (multiplied contact time and less than half coefficient of restitution). Fabricated inertial switches have been installed into a vibration system to test fundamental characteristics. Under vibration conditions with amplitude of 0.6 g and frequencies from 25 to 40 Hz, the devices achieve reliable switching with triggering time ranging from 81.2 to 119.3 μs.

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Mechanical latching stops for reliability improvement of MEMS in shock environments

Cited by 8 publications

References 31 publications

Recent Advancements in Inertial Micro-Switches

Recent Advancements in Inertial Micro-Switches

Reliability of MEMS in Shock Environments: 2000–2020

Micromachined inertial switch for sub‐g monitoring using gravity‐based threshold compensation

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