MEMS device with piezoelectric actuation, a projective MEMS system including the MEMS device and related control method

A The MEMS device, comprising:

• a fixed structure delimiting a cavity;
• a suspended structure which overlies the cavity, the suspended structure comprising:
• an internal structure;
• and
• a first arm and a second arm which are arranged around the internal structure and each of the first and second arms having a respective first end and a respective second end, said first ends being fixed to the fixed structure and being angularly arranged at a distance apart, said second ends being fixed to the internal structure and being angularly arranged at a distance apart and being angularly arranged in a same direction of rotation with respect to the corresponding first ends;
• wherein, in a resting condition, the first and second arms respectively have first and second elongated portions having respective single concavities, said internal structure extending in part within the concavities of the first and second elongated portions;
• and
• a plurality of piezoelectric actuators coupled to the first arm and the second arm and configured when driven to cause a deformation of the arm to which the piezoelectric actuator is coupled and a consequent rotation of the internal structure;
• wherein the first and second elongated portions form, respectively, the first ends of the first and second arms;
• wherein the first and second arms further comprise, respectively, a first terminal portion and a second terminal portion, which form, respectively, the second ends of the first and second arms;
• and
• wherein the first and second terminal portions connect, respectively, to corresponding parts of the first and second elongated portions and form curved projections with single concavity, with concavity facing the internal structure, said curved projections projecting radially with respect to said parts of the first and second elongated portions.

A MEMS device, comprising:

• a fixed structure delimiting a cavity;
• a suspended structure which overlies the cavity, the suspended structure comprising:
• an internal structure;
• and
• a first arm and a second arm which are arranged around the internal structure and each of the first and second arms having a respective first end and a respective second end, said first ends being fixed to the fixed structure and being angularly arranged at a distance apart, said second ends being fixed to the internal structure and being angularly arranged at a distance apart and being angularly arranged in a same direction of rotation with respect to the corresponding first ends;
• wherein, in a resting condition, each of the first and second arms has a respective elongated portion with a respective concavity, said internal structure extending in part within the concavities of the elongated portions of the first and second arms;
• and
• a plurality of piezoelectric actuators coupled to the first arm and the second arm and configured when driven to cause a deformation of the arm to which the piezoelectric actuator is coupled and a consequent rotation of the internal structure;
• wherein each of said piezoelectric actuators is arranged on the elongated portion of the arm to which it is coupled;
• and
• wherein the plurality of piezoelectric actuators comprises a first piezoelectric actuator, a second piezoelectric actuator, a third piezoelectric actuator, and a fourth piezoelectric actuator, the first and third piezoelectric actuators being arranged on the elongated portion of the first arm, the second and fourth piezoelectric actuators being arranged on the elongated portion of the second arm, in a way symmetrical, respectively, to the first and second piezoelectric actuators.

A MEMS device, comprising:

• a fixed structure delimiting a cavity;
• a suspended structure which overlies the cavity, the suspended structure comprising:
• an internal structure;
• and
• a first arm and a second arm which are arranged around the internal structure and each of the first and second arms having a respective first end and a respective second end, said first ends being fixed to the fixed structure and being angularly arranged at a distance apart, said second ends being fixed to the internal structure and being angularly arranged at a distance apart and being angularly arranged in a same direction of rotation with respect to the corresponding first ends;
• wherein, in a resting condition, each of the first and second arms has a respective elongated portion with a respective concavity, said internal structure extending in part within the concavities of the elongated portions of the first and second arms;
• a plurality of piezoelectric actuators coupled to the first arm and the second arm and configured when driven to cause a deformation of the arm to which the piezoelectric actuator is coupled and a consequent rotation of the internal structure;
• and
• a third arm and a fourth arm, each of third and fourth arms comprising a respective elongated portion having a concavity;
• and wherein, in the resting condition, the elongated portions of the first and second arms extend at least in part within the concavities formed, respectively, by the elongated portions of the third and fourth arms.

A MEMS device, comprising:

• a fixed structure delimiting a cavity;
• a suspended structure which overlies the cavity, the suspended structure comprising:
• an internal structure;
• and
• a first arm and a second arm which are arranged around the internal structure and each of the first and second arms having a respective first end and a respective second end, said first ends being fixed to the fixed structure and being angularly arranged at a distance apart, said second ends being fixed to the internal structure and being angularly arranged at a distance apart and being angularly arranged in a same direction of rotation with respect to the corresponding first ends;
• wherein, in a resting condition, each of the first and second arms has a respective elongated portion with a respective concavity, said internal structure extending in part within the concavities of the elongated portions of the first and second arms;
• and
• a plurality of piezoelectric actuators coupled to the first arm and the second arm and configured when driven to cause a deformation of the arm to which the piezoelectric actuator is coupled and a consequent rotation of the internal structure;
• wherein said internal structure comprises:
• a nested structure;
• and
• an outer frame of an annular shape, which surrounds the nested structure, and fixed to which are the second ends of the first and second arms;
• and
• wherein the nested structure comprises:
• an inner frame;
• and
• a first secondary arm and a second secondary arm arranged around the inner frame and each of the first and second secondary arms having a respective first end and a respective second end, said first ends the first and second secondary arms being fixed to the outer frame and being angularly arranged at a distance apart, said second ends the first and second secondary arms being fixed to the inner frame and being angularly arranged at a distance apart and being arranged angularly in a same direction of rotation with respect to the corresponding first ends;
• and
• a further plurality of piezoelectric actuators coupled to the first secondary arm and the second secondary arm and configured when driven to cause a deformation of the secondary arm to which the piezoelectric actuator is coupled and a consequent rotation of the inner frame;
• wherein each of the first and second secondary arms comprises a respective elongated portion with a respective concavity;
• and wherein, in the resting condition, said inner frame extends in part within the concavities of the elongated portions of the first and second secondary arms.

A MEMS device, comprising:

• a fixed structure delimiting a cavity;
• a suspended structure which overlies the cavity, the suspended structure comprising:
• an internal structure;
• and
• a first arm and a second arm which are arranged around the internal structure and each of the first and second arms having a respective first end and a respective second end, said first ends being fixed to the fixed structure and being angularly arranged at a distance apart, said second ends being fixed to the internal structure and being angularly arranged at a distance apart and being angularly arranged in a same direction of rotation with respect to the corresponding first ends;
• wherein, in a resting condition, each of the first and second arms has a respective elongated portion with a respective concavity, said internal structure extending in part within the concavities of the elongated portions of the first and second arms;
• a plurality of piezoelectric actuators coupled to the first arm and the second arm and configured when driven to cause a deformation of the arm to which the piezoelectric actuator is coupled and a consequent rotation of the internal structure;
• and
• at least one first strain gauge and one second strain gauge, which are mechanically coupled, respectively, to the first and second arms, in symmetrical positions.