Stmicroelectronics S.r.l.

Nicolo′ Boni

Roberto Carminati

Massimiliano Merli

Enri Duqi

Carlo Luigi Prelini

Gianluca Mendicino

Tarek Afifi Afifi

A microelectromechanical mirror device has, in a die of semiconductor material: a fixed structure defining a cavity; a tiltable structure carrying a reflecting region, elastically suspended above the cavity and having a main extension in a horizontal plane; at least one first pair of driving arms, carrying respective piezoelectric structures which can be biased to generate a driving force that causes rotation of the tiltable structure about a rotation axis parallel to a first horizontal axis of the horizontal plane; elastic suspension elements, which elastically couple the tiltable structure to the fixed structure at the rotation axis and are rigid to movements out of the horizontal plane and compliant to torsion about the rotation axis. In particular, the driving arms of the first pair are magnetically coupled to the tiltable structure to cause its rotation about the rotation axis by magnetic interaction, following biasing of the respective piezoelectric structures.

Microelectromechanical mirror device with piezoelectric actuation having improved stress resistance

A microelectromechanical mirror device has, in a die of semiconductor material: a fixed structure defining a cavity; a tiltable structure carrying a reflecting region elastically suspended above the cavity; at least a first pair of driving arms coupled to the tiltable structure and carrying respective piezoelectric material regions which may be biased to cause a rotation thereof around at least one rotation axis; elastic suspension elements coupling the tiltable structure elastically to the fixed structure and which are stiff with respect to movements out of the horizontal plane and yielding with respect to torsion; and a piezoresistive sensor configured to provide a detection signal indicative of the rotation of the tiltable structure. At least one test structure is integrated in the die to provide a calibration signal indicative of a sensitivity variation of the piezoresistive sensor in order to calibrate the detection signal.

Microelectromechanical mirror device with piezoelectric actuation and piezoresistive sensing having self-calibration properties

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Mountain View, CA, United States of America

Nicolo′ Boni