Microelectromechanical mirror device with piezoelectric actuation and optimized size

An electronic device including a microelectromechanical mirror device, the microelectromechanical mirror device comprising a first tiltable mirror structure provided in a first die of semiconductor material having a main extension in a horizontal plane defined by first and second horizontal axes, wherein said first tiltable mirror structure comprises:

• a fixed structure defining a frame which delimits a cavity;
• a tiltable element carrying a reflecting region, elastically suspended above the cavity and having first and second median axes of symmetry, respectively parallel to said first and second horizontal axes, said tiltable element being elastically coupled to said frame by first and second coupling structures on opposite sides of said second horizontal axis;
• and
• a driving structure coupled to the tiltable element and configured to cause it to rotate around the first horizontal axis with a resonance movement;
• wherein said first tiltable mirror structure is asymmetrical with respect to the second horizontal axis and has, along the first horizontal axis:
• a first extension dimension on a first side of said second horizontal axis;
• and
• a second extension dimension, greater than the first extension dimension, on a second side of said second horizontal axis opposite to the first side;
• wherein said first coupling structure is arranged on the first side of the second horizontal axis and comprises a single torsional spring having a first end coupled to the tiltable element and a second end coupled to the frame and having linear extension along the first horizontal axis;
• and
• wherein the second coupling structure comprises a first torsional spring and a second torsional spring having extension along the first horizontal axis, and a constraint element interposed between said first and second torsional springs, said first torsional spring having a first end coupled to the tiltable element and a second end coupled to the constraint element and said second torsional spring having a first end coupled to the constraint element on opposite side with respect to the first torsional spring along the first horizontal axis and a second end coupled to the frame.

An electronic device including a microelectromechanical mirror device, the microelectromechanical mirror device comprising a first tiltable mirror structure provided in a first die of semiconductor material having a main extension in a horizontal plane defined by first and second horizontal axes, wherein said first tiltable mirror structure comprises:

• a fixed structure defining a frame which delimits a cavity;
• a tiltable element carrying a reflecting region, elastically suspended above the cavity and having first and second median axes of symmetry, respectively parallel to said first and second horizontal axes, said tiltable element being elastically coupled to said frame by first and second coupling structures, on opposite sides of said second horizontal axis;
• and
• a driving structure coupled to the tiltable element and configured to cause it to rotate around the first horizontal axis with a resonance movement;
• wherein said first tiltable mirror structure is asymmetrical with respect to the second horizontal axis and has, along the first horizontal axis:
• a first extension dimension on a first side of said second horizontal axis;
• and
• a second extension dimension, greater than the first extension dimension, on a second side of said second horizontal axis opposite to the first side;
• a second tiltable mirror structure provided with a tiltable element, configured to rotate around a rotation axis with linear or quasi-static movement and arranged to cooperate with the tiltable element of said first tiltable mirror structure for directing an impinging light beam;
• wherein said second tiltable mirror structure is provided in a second die of semiconductor material having a main extension in a horizontal plane defined by first and second horizontal axes and having a fixed structure defining a frame which delimits a cavity wherein the tiltable element is arranged;
• said frame defining an outer side surface of the second die having a concavely patterned shape to define a recess which accommodates at least in part the first die of said first tiltable mirror structure.

An electronic device comprising a microelectromechanical mirror device with a first tiltable mirror structure in a first semiconductor material die, extending in a horizontal plane defined by first and second horizontal axes, wherein the first tiltable mirror structure includes:

• a frame enclosing a cavity;
• a tiltable, reflective element with first and second median symmetry axes parallel to the first and second horizontal axes, elastically connected to the frame by first and second coupling mechanisms on opposite sides of the second horizontal axis;
• and
• a driving mechanism linked to the tiltable, reflective element to induce rotation around the first horizontal axis using a resonant movement;
• wherein the first tiltable mirror structure is asymmetrical concerning the second horizontal axis and has varying extension dimensions along the first horizontal axis;
• wherein the first coupling mechanism, positioned on the first side of the second horizontal axis, comprises a single torsional spring connected to the tiltable, reflective element and the frame, extending linearly along the first horizontal axis;
• wherein the second coupling mechanism includes first and second torsional springs extending along the first horizontal axis, and a constraint component between the first and second torsional springs, with the first and second torsional springs connected to the tiltable, reflective element, constraint component, and frame.