Electrostatically actuated oscillating structure with oscillation starting phase control, and manufacturing and driving method thereof

An electrostatically actuated oscillating structure, comprising:

• a fixed support body forming a first stator subregion, a second stator subregion, a first rotor subregion and a second rotor subregion;
• a first torsional elastic element and a second torsional elastic element mechanically coupled, respectively, to the first and second rotor subregions and defining an axis of rotation parallel to a first direction of an orthogonal reference system;
• and
• a mobile element arranged between, and connected to, said first and second torsional elastic elements, the mobile element being rotatable about the axis of rotation as a result of a torsion of the first and second torsional elastic elements;
• wherein the first and second stator subregions are electrostatically coupled to respective first and second regions of actuation of the mobile element, which are diametrically opposite to one another with respect to the axis of rotation,
• wherein one of the first and second stator subregions includes at least an element of structural asymmetry such that a surface available for said electrostatic coupling between the first stator subregion and the first actuation region is greater than a surface available for the electrostatic coupling between the second stator subregion and the second actuation region;
• wherein said element of structural asymmetry is a bump element of increased thickness housed by the first stator subregion such as to increase a spatial extension, in a second direction orthogonal to said first direction, of a portion of the first stator subregion with respect to a spatial extension in said second direction of a corresponding portion of the second stator subregion;
• wherein the first and second regions of actuation of the mobile element include a respective plurality of first and second elongated elements, which extend in cantilever fashion towards the first and second stator subregions, respectively, the first and second stator subregions including a respective plurality of third and fourth elongated elements comb-fingered to the first and second elongated elements, respectively;
• and
• wherein said bump element of increased thickness extending, at least in part, on the third elongated elements, so that the surface available for said electrostatic coupling between the third elongated elements and the first elongated elements is greater than the surface available for the electrostatic coupling between the fourth elongated elements and the second elongated elements.