Silicon MEMS acceleration switch with high reliability using hooked latch

Lee, Yeonsu; Sim, Sung-Min; Kim, Yong-Kweon; Kim, Jung-Mu

doi:10.1016/j.mee.2015.12.016

Cited by 17 publications

(10 citation statements)

References 10 publications

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“…The common methods include the mechanical locking mechanism and the bistable mechanism. Mechanical locking switches utilize a pair of mechanical locks to buckle electrodes together [90,91]. The design of the mechanical locking switch requires consideration of an unlocking mechanism to release the movable electrode, without which the switch will remain on after being triggered.…”

Section: Passive Inertial Switchesmentioning

confidence: 99%

Research Status and Development Trend of MEMS Switches: A Review

Cao

Zhao

2020

Micromachines

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MEMS switch is a movable device manufactured by means of semiconductor technology, possessing many incomparable advantages such as a small volume, low power consumption, high integration, etc. This paper reviews recent research of MEMS switches, pointing out the important performance indexes and systematically summarizing the classification according to driving principles. Then, a comparative study of current MEMS switches stressing their strengths and drawbacks is presented, based on performance requirements such as driven voltage, power consumption, and reliability. The efforts of teams to optimize MEMS switches are introduced and the applications of switches with different driving principles are also briefly reviewed. Furthermore, the development trend of MEMS switch and the research gaps are discussed. Finally, a summary and forecast about MEMS switches is given with the aim of providing a reference for future research in this domain.

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Section: Passive Inertial Switchesmentioning

confidence: 99%

Research Status and Development Trend of MEMS Switches: A Review

Cao

Zhao

2020

Micromachines

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“…Since the first inertial micro-switch was reported in 1972 [ 5 ], a great number of inertial micro-switches have been developed, and they can be simply grouped into two categories: persistent switches, wherein the switch was designed with a keep-close function that can keep it closed after the acceleration event is over, and intermittent switches, wherein the switch re-opens after the acceleration dissipates. Persistent switches such as the latching switch [ 6 , 7 , 8 ], the bi-stable switch [ 9 , 10 ], and the micro-fluidic switch [ 11 , 12 ] has an excellent contact effect but usually requires an additional operation or structure to re-open itself, resulting in inconvenience for some applications wherein repeated monitoring is needed. On the other hand, the intermittent switch can sense the acceleration theoretically for an unspecified number of iterations.…”

Section: Introductionmentioning

confidence: 99%

A Low-G Silicon Inertial Micro-Switch with Enhanced Contact Effect Using Squeeze-Film Damping

Peng

Zhang

et al. 2017

Sensors

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Abstract:Contact time is one of the most important properties for inertial micro-switches. However, it is usually less than 20 µs for the switch with rigid electrode, which is difficult for the external circuit to recognize. This issue is traditionally addressed by designing the switch with a keep-close function or flexible electrode. However, the switch with keep-close function requires an additional operation to re-open itself, causing inconvenience for some applications wherein repeated monitoring is needed. The switch with a flexible electrode is usually fabricated by electroplating technology, and it is difficult to realize low-g switches (<50 g) due to inherent fabrication errors. This paper reports a contact enhancement using squeeze-film damping effect for low-g switches. A vertically driven switch with large proof mass and flexible springs was designed based on silicon micromachining, in order to achieve a damping ratio of 2 and a threshold value of 10 g. The proposed contact enhancement was investigated by theoretical and experimental studies. The results show that the damping effect can not only prolong the contact time for the dynamic acceleration load, but also reduce the contact bounce for the quasi-static acceleration load. The contact time under dynamic and quasi-static loads was 40 µs and 570 µs, respectively.

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“…The switches with a keep-close function can keep it closed after the acceleration event is over, thus improving the contact reliability. However, the keep-close function requires special constructions, such as the hook-shaped electrodes of the latching switches [ 6 , 7 , 8 ], the V-shaped beams of the bi-stable switches [ 9 , 10 ], and the valve-channel of the micro-fluidic switches [ 11 , 12 ], complicating the structure topology or working mechanism or fabrication method, thus reducing the threshold accuracy, as shown in Table 1 . The latching switch with a 50.59 g designed threshold value in Ref.…”

Section: Introductionmentioning

confidence: 99%

“…The latching switch with a 50.59 g designed threshold value in Ref. [ 7 ], for instance, was first switched on when the applied acceleration was between 28 g and 43.7 g , and it was completely closed when a higher acceleration was applied. This is due to the collision and friction contact process of the two hook-shaped electrodes.…”

Section: Introductionmentioning

confidence: 99%

A 5 g Inertial Micro-Switch with Enhanced Threshold Accuracy Using Squeeze-Film Damping

Peng

Pan

et al. 2018

Micromachines

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Our previous report based on a 10 g (gravity) silicon-based inertial micro-switch showed that the contact effect between the two electrodes can be improved by squeeze-film damping. As an extended study toward its potential applications, the switch with a large proof mass suspended by four flexible serpentine springs was redesigned to achieve 5 g threshold value and enhanced threshold accuracy. The impact of the squeeze-film damping on the threshold value was theoretically studied. The theoretical results show that the threshold variation from the designed value due to fabrication errors can be reduced by optimizing the device thickness (the thickness of the proof mass and springs) and then establishing a tradeoff between the damping and elastic forces, thus improving the threshold accuracy. The design strategy was verified by FEM (finite-element-method) simulation and an experimental test. The simulation results show that the maximum threshold deviation was only 0.15 g, when the device thickness variation range was 16–24 μm, which is an adequately wide latitude for the current bulk silicon micromachining technology. The measured threshold values were 4.9–5.8 g and the device thicknesses were 18.2–22.5 μm, agreeing well with the simulation results. The measured contact time was 50 μs which is also in good agreement with our previous work.

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Silicon MEMS acceleration switch with high reliability using hooked latch

Cited by 17 publications

References 10 publications

Research Status and Development Trend of MEMS Switches: A Review

Research Status and Development Trend of MEMS Switches: A Review

A Low-G Silicon Inertial Micro-Switch with Enhanced Contact Effect Using Squeeze-Film Damping

A 5 g Inertial Micro-Switch with Enhanced Threshold Accuracy Using Squeeze-Film Damping

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