Solid-state inertial sensor on chip

Abstract

Monolithic solid-state inertial sensor. The sensor detects rotation rate about three orthogonal axes and includes a micromachined monolithic piezoelectric crystalline structure including an equal number of vibratory drive and detection tines on each side of an axis of symmetry of the sensor, the tines being synchronized to have alternate actuation movements inward and outward.

1 . Monolithic solid-state inertial sensor for detection of rotation rate about three orthogonal axes comprising:
 a micromachined monolithic piezoelectric crystalline structure including an equal number of vibratory drive and detection tines on each side of an axis of symmetry of the sensor, the tines being synchronized to have alternative actuation movements inward and outward.   
     
     
         2 . The inertial sensor of  claim 1  further including two pairs of vibratory elements separated by a 60 degrees angle on each side of the axis of symmetry, wherein each pair of vibratory elements includes one vibrating tuning tine and one detection tine parallel to each other and linked by a common base. 
     
     
         3 . The inertial sensor of  claim 2  wherein the sensor includes a trench in a central portion creating a left and right side supporting the vibratory sensors. 
     
     
         4 . The inertial sensor of  claim 1  including six detection tines coupled at resonance frequency to four parallel drive tines for detection of out-of-plane vibration due to rotation around any axis of rotation. 
     
     
         5 . The inertial sensor of  claim 3  wherein the sensor undergoes a waving effect from left to right when rotated about a Y-axis to create a maximal electrical signal from detection tines on each side of the trench. 
     
     
         6 . The inertial sensor of  claim 3  that has a waving effect from the front end to the back end when rotated around an X-axis according to the direction of the actuation from drive elements to create a maximal electrical signal from the group of tines from the back end and the front end. 
     
     
         7 . Monolithic solid-state inertial sensor having independent gyroscope function on three orthogonal axes of rotation and accelerometer function along three orthogonal axes of linear displacement comprising a torsion bar and four vibrating beam accelerometers, each one having an independent proof mass, a connection arm, a pivot point to allow movement of the connection arm along a sensitive axis, and a vibrating beam.