Journal of Theoretical and Applied Information Technology
10
th
February 2013. Vol. 48 No.1
© 2005 - 2013 JATIT & LLS. All rights reserved
.
ISSN: 1992-8645 www.jatit.org E-ISSN: 1817-3195
454
MODELING AND MICRO SCALE ANALYZING OF MICRO-
SWITCH APPLIED IN ALL-OPTICAL COMMUNICATION
1
TIAN WENCHAO,
2
CHEN ZHIQIANG
1
,
2
School of Electro-Mechanical Engineering, Xidian University, Xi'an, 710071, China
E-mail: tianwenchao@21cn.com
ABSTRACT
Inductive micro-switch is an integrative device of a sensor and actuator and widely applied in all-optical-
network communication. Its malfunctions related to “fail-to-closure” and “transient-closure” result in low
reliability and weak anti-jamming capability. A new bistable inductive micro-switch is presented based on
micro electro-mechanical system (MEMS) technology. A sine rough surface model is used to describe the
random distribution of the rough adhesive surface. Micro size Casimir and van der Waals (vdW) forces are
analyzed in detail. The vdW force includes the repulsive force. Dynamic simulation results are shown to be
in agreement with experimental results. The threshold acceleration was 6.8g, and the response time was
17.5μs. A “double-snap-back” phenomenon in the Off-state is discovered.
Keywords: Inductive Micro-Switch; Casimir Force; Van Der Waals Force; Double-Snap-Back
1. INTRODUCTION
Micro-switch is a key device in all-optical-net
communication and widely applied Optical Layer
Cross Connect (OLXC). Based on the MEMS
technology, an inductive micro-switch can not only
induce an external acceleration, but can also be
controlled by the external acceleration to realize the
optical trigger action. When the external
acceleration is less than the threshold acceleration,
the micro-switch maintains its Off-state. When the
external acceleration reaches the threshold value,
the micro-switch is triggered quickly to realize its
On-state automatically, and an external circuit is
switched on.
The inductive micro-switch is an integrative
device consisting of a sensor and actuator. It is
small, simple, low-cost, highly sensitive and fast
responsive. Based on these characteristics, the
inductive micro-switch is applied widely in the
triggering field, such as in the automotive air
restraint system, space probe callback system,
fairing firing separation system, crashworthy data
protection system of portable computer etc. Zhao et
al design a micro-switch with a post-bucking
structure for the airbag restraint system [1].
However, their micro-switch beam is too fragile
making it too difficult to assemble. Alexander et al
design a dual-mass-spring micro-switch [2], which
used an inductive mass to induct the external
acceleration. That design has a “fail-to-closure”
problem such that before the external acceleration
reaches the threshold acceleration, the inductive
mass could strike the fixed electrode inducing a
premature On-state. Therefore, the system’s
reliability is very low. Yang et al design a snake-
shape beam micro-switch [3]. In that design when
the external acceleration reaches the threshold
acceleration, an inductive mass strikes the fixed
electrode to realize the trigger action. But the elastic
force pulls the inductive mass quickly back to the
Off-state. Therefore, this micro-switch can not
realize a stable contact, and the external circuit can
not maintain a stable On-state. It clearly has a
problem of “transient-closure”. Du et al analyze the
plastic deformation in the micro-switch contact area
[4]. Esquivel analyzes the Casimir force in the
micro-switch [5]. Ongkodjojo et al design a micro
switch for health care applications [6]. However,
the micro switch can not precisely and reliably
control the external circuit to switch.
Little work has been done to develop a
comprehensive model to accurately analyze the
micro size force during the micro-switch contact
process. Therefore, current inductive micro-
switches lack stability in the Off-state or On-state,
and can not trigger accurately at the threshold
acceleration. Malfunction of the existing inductive
micro-switch, i.e., “fail-to-closure” and “transient-
closure”, results in low reliability and weak anti-
jamming capability.
In this paper, we present an inductive micro-
switch with a bistable structure based on the
adhesive effect. A sine-model is used to describe
the rough contact surface of the micro-switch.