MEMS vibrating-beam accelerometer with piezoelectric drive
A high-temperature drive component for a double-ended tuning fork (DETF). The drive component attaches to a surface of at least one of the tines. The drive component includes at least one piezoelectric trace sandwiched at least partially between two electrical traces. At least one of the tines includes a doped silicon base with drive component located thereon. One of the electrical traces is electrically connected to the doped silicon base and the other is electrically isolated from the doped silicon base.
1. A double-ended tuning fork (DETF) device comprising:
a first base;
a second base;
first and second tines attached to the first base at a first end and to the second base at a second end, the first and second tines lying in a plane; and
a drive component attached to a top surface of at least the first tine and offset laterally from a longitudinal bending neutral axis of the first tine, wherein the drive component is configured to cause the tines to oscillate in the plane, wherein the drive component comprises:
a first subcomponent including at least a first piezoelectric drive trace and at least a first electrical drive trace, wherein the first subcomponent is located on a middle section of the first tine and is offset laterally from the longitudinal bending neutral axis of the first tine; and
a second subcomponent including at least a second piezoelectric drive trace and at least a second electrical drive trace, wherein the second subcomponent is located between the middle section of the first tine and the first end of the first tine and is offset laterally from the longitudinal bending neutral axis of the first tine opposite that of the first subcomponent,
wherein the electrical drive traces of the first and second subcomponents are electrically connected.
2. The device of claim 1 ,
wherein the first and second tines each comprise a doped silicon base,
wherein the second subcomponent further includes a third electrical drive trace,
wherein the second piezoelectric drive trace is located between the second and third electrical drive traces, and
wherein the second electrical drive trace is electrically connected to the doped silicon base and the third electrical drive trace is electrically isolated from the doped silicon base.
3. The device of claim 1 , wherein the drive component is located on both the first and second tines.
4. The device of claim 1 , further comprising a sense component attached to at least one surface of the second tine and offset laterally from a longitudinal bending neutral axis of the second tine, wherein the sense component comprises:
at least one piezoelectric sense trace; and
at least one electrical sense trace.
5. The device of claim 4 , further comprising a controller configured to:
apply a voltage across the first piezoelectric drive trace and the second piezoelectric drive trace of the drive component via the first electrical drive trace and the second electrical drive trace of the drive component;
receive a sense signal from the sense component, wherein the sense signal is associated with motion of the first and second tines; and
alter the voltage applied across the first piezoelectric drive trace and the second piezoelectric drive trace of the drive component based on the received sense signal to drive the first and second tines to oscillate at a resonant frequency of the first and second tines.
6. The device of claim 1 , wherein the first piezoelectric drive trace and the second piezoelectric drive trace are bonded directly to the top surface of the first tine.
7. The device of claim 1 ,
wherein the first tine comprises a silicon beam,
wherein the first piezoelectric drive trace and the second piezoelectric drive trace are configured to expand and contract relative to the silicon beam, and
wherein the expansion and contraction of the first piezoelectric drive trace and the second piezoelectric drive trace causes the silicon beam to bend.