Micro inertial switch with Z-shaped beam structure

Abstract

The invention provides a micro inertial switch with a Z-shaped beam structure. The micro inertial switch has a micro inertial switch chip which is processed according to MEMS technology and has a low g-value. The micro inertial switch is mainly composed of a glass cover plate, a mass block and spring beam silicon structure, a glass substrate, etc. The spring beam structure is a symmetrical Z-shaped beam. In operation, on the condition an overload function exists in a sensitive direction, the Z-shaped beam deforms elastically, and the mass block moves to contact bump points in the groove of the glass substrate. On the condition that overload reaches a certain threshold, a metal electrode on the mass block contacts with two random adjacent contact pump points in the groove of the substrate, so that the micro inertial switch is on. The micro inertial switch with the Z-shaped beam structure has advantages of high transverse overload resistance, high productivity, high reliability, etc. The micro inertial switch with the Z-shaped beam structure is suitable for the fields such as automobile and industrial production safety control and aeronautics and astronautics.

Description

technical field [0001] The invention belongs to the technical field of micro-electromechanical systems, and in particular relates to a micro-inertial switch with a Z-beam structure. Background technique [0002] The low-g value inertial switch is sensitive to inertial acceleration, and the switch state changes when the inertial acceleration reaches the set threshold, that is, the normally open contact is turned on or the normally closed contact is disconnected, which can be used to trigger the control circuit and is widely used in automotive safety control , industrial production safety control, aircraft flight process status monitoring and other fields. Traditional confidential mechanical inertial switches have complex structures and are usually assembled from balls, springs, pins, screws and other parts that require high dimensional accuracy, so they are large in size, high in processing and assembly costs, long in cycle time, and prone to mechanical failure. The low-g va...

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Problems solved by technology

The first electroformed nickel folded beam as reported in the article "Fabrication of a novel contact-enhanced horizontal sensitive inertia micro-switch with electroplating nickel" (P21-27) in "Microelectronic Engineering" Issue 127 published in February 2014 Structural micro-inertia switch, mass block thickness 60um, folded beam thickness 15um, switch action threshold is about 18g, but because the material of the switch contact and the structural layer are nickel, the conduction resistance of the inertial switch is relatively large, and the folded spring beam surface is used It is difficult to make the elastic coefficient small in the inner motion direction, and the first-order resonant frequency of the inertial switch is prone to misoperation in the vibrating environment

The second one is based on Archimedes, as reported in the article "Low-g micro inertia switchbased on Archimedes's spiral" (P1257-1261) in "Optical Precision Engineering", Volume 17, Issue 6, published in June 2009 in China. The micro-inertia switch of the spiral wire has a switching threshold of about 21g, but because a single Archimedes spiral beam is used and the thickness is the same as that of the mass block, the contact contact is a line contact, the contact reliability is low, and the on-resistance is large; China 2011 A micro-inertial switch based on a rectangular helical beam was reported in the article "Design and Fabrication of a Low-g Micro-Inertial Switch Based on MEMS Technology" in the "Journal of Sensor Technology" Volume 24 Issue 5 published in May 2009. The threshold value is about 4.28g, but the stress of the rectangular spiral beam is relatively large and because the mass block is surrounded by beam structures, it is impossible to make a protective structure against lateral overload. Too long a rectangular spiral beam will also cause the inertial force of the beam itself under high overload. Under strong vibration impact, the beam will break due to its own inertial force, so this kind of low-g value inertia switch has poor vibration and impact resistance

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