MEMS VIBRATING-BEAM ACCELEROMETER WITH PIEZOELECTRIC DRIVE

• US 20120192649A1
• Filed: 02/02/2011
• Published: 08/02/2012
• Est. Priority Date: 02/02/2011
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Strehlow, John, MacGugan, Doug
• Granted Patent: US 9,759,739 B2
• Time in Patent Office: Days
• US Class Current: 73/504.16
• CPC Class Codes: G01L 1/162 using piezoelectric resonators
• CPC Class Codes: G01P 15/097 by vibratory elements
• CPC Class Codes: H03H 2009/02496 Horizontal, i.e. parallel to the substrate plane
• CPC Class Codes: H03H 9/02259 Driving or detection means
• CPC Class Codes: H03H 9/2473 Double-Ended Tuning Fork [DETF] resonators

Abstract

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.

Claims

1. A double-ended tuning fork (DETF) device comprising:

first and second tines attached to a first base at a first end and to a second base at a second end; and

a drive component attached to at least one surface of at least one of the tines and is offset laterally from a longitudinal bending neutral axis of the tine, the drive component comprises;

at least one piezoelectric trace; and

at least one electrical trace.

2. The device of claim 1, wherein at least one of the tines comprises a doped silicon base, wherein the at least one drive component comprises first and second electrical traces, wherein the at least one piezoelectric trace is located between the first and second electrical traces, wherein the first electrical trace is electrically connected to the doped silicon base and the second electrical trace is electrically isolated from the doped silicon base.

3. The device of claim 1, wherein the drive component is located on both of the tines.

4. The device of claim 1, wherein the drive component comprises a first subcomponent comprising at least one piezoelectric trace and at least one electrical trace and a second subcomponent comprising at least one piezoelectric trace and at least one electrical trace, wherein the electrical traces of the first and second subcomponents are electrically connected.

5. The device of claim 4, wherein the first subcomponent is located on a longitudinal mid length of the tine and offset laterally from the longitudinal bending neutral axis and the second subcomponent is located on at least one longitudinal length from near an end of the first subcomponent to near an end of the tine and offset laterally from the longitudinal bending neutral axis opposite that of the first subcomponent.

6. The device of claim 1, further comprising:

a sense component attached to at least one surface of at least one of the tines and is offset laterally from a longitudinal bending neutral axis, the sense component comprises;

at least one piezoelectric trace; and

at least one electrical trace.

7. A method for driving a double-ended tuning fork (DETF) having two tines, the method comprising:

periodically varying a voltage across at least one drive piezoelectric trace located on at least one the tines of the DETF, thereby causing the tines of the DETF to oscillate in an in-plane direction at a resonant frequency;

receiving a sense signal from a sense device, wherein the sense signal is associated with motion of the tines of the DETF; and

altering the voltage applied to the at least one drive piezoelectric trace based on the received sense signal, thereby driving the tines of the DETF to oscillate at the resonant frequency.

8. The method of claim 7, wherein receiving a sense signal comprises:

receiving the sense signal from a pair of electrodes configured to receive a capacitive voltage that varies depending upon the force applied to at least one piezoelectric trace associated with the pair of electrodes.

9. The method of claim 7, wherein receiving comprises:

receiving the sense signal from a piezoresistive component located on at least one the tines, the piezoresistive component configured to provide a resistance that varies depending upon the force applied to the at least one tine.

10. A system for driving a double-ended tuning fork (DETF) having two tines, the system comprising:

a means for periodically varying a voltage across at least one drive piezoelectric trace located on at least one the tines of the DETF, thereby causing the tines of the DETF to oscillate in an in-plane direction at a resonant frequency;

a means for receiving a sense signal from a sense device, wherein the sense signal is associated with motion of the tines of the DETF; and

a means for altering the voltage applied to the at least one drive piezoelectric trace based on the received sense signal, thereby driving the tines of the DETF to oscillate at the resonant frequency.

11. The system of claim 10, wherein the means for receiving is configured to receive a capacitive voltage that varies depending upon the force applied to at least one piezoelectric trace associated with the pair of electrodes.

12. The system of claim 10, wherein the means for receiving the sense signal comprises:

a piezoresistive component configured to provide a resistance that varies depending upon the force applied to one of the tines.