Micromechatronics Quiz 2 (due 2015/1/13)
send your answer (preferably in pdf) to <f3hisyo@iis.u-Tokyo.ac.jp>
• Design an electromagnetic microactuator for pressing the square mirror
down to the substrate. The mirror structure is shown in Fig. 1.
• Obtain the stiffness of a silicon suspension of length of Lb, width of Wb and thickness
of Tb. Its both ends are rigidly clamped and deforms out of plane of the substrate.
• Hint: It can be represented by two cantilevers connected in series.
• Draw the shape of electrical wiring in the top view of Fig. 1 and the direction of the
external magnetic field.
• Assuming that the wiring thickness is much thinner than the suspension, calculate the
necessary current to displace the mirror over Tg to close the gap completely. The flux
density of the external magnetic field is B [T]. Please ignore the force on the
suspensions.
• You may define necessary material parameters, if needed.
Wb
Lb
Lm
Tb
Si-10mm
Tg La
SiO2
Si-500mm
Fig. 1 Suspended mirror device
Fig. 2 After actuation