Micromechanical system

• US 9,003,881 B2
• Filed: 08/03/2011
• Issued: 04/14/2015
• Est. Priority Date: 08/04/2010
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Neul, Reinhard, Meisel, Daniel Christoph
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US13/197,100
• Publication Number:
  US 20120031183A1
• Time in Patent Office: 1,350 Days
• Field of Search: 735/040.2, 735/041.2
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5755 the devices having a single sensing mass

Abstract

A yaw-rate sensor for determining a Coriolis force includes a semiconductor substrate, a mass body mounted so it is movable over the semiconductor substrate, a drive unit for setting the mass body into an oscillating movement, and a detection unit for determining a deflection of the mass body which is caused by the Coriolis force. The detection unit includes a piezoresistive element, whose electrical resistance is a function of the deformation of the piezoresistive element.

Claims

1. A yaw-rate sensor for determining a Coriolis force, comprising:

a semiconductor substrate;

a mass body mounted so it is movable over the semiconductor substrate, wherein the mass body includes two mass elements set to move in different directions;

a drive unit for setting the mass body into an oscillating movement in a plane of the mass body; and

a detection unit for determining deflections of the mass elements within the plane and caused by the Coriolis force, the detection unit including a piezoresistive element, wherein a piezoresistive element is operationally linked to the semiconductor substrate and a lever element, which is mounted in an anchor point so it is rotatable on the semiconductor substrate, is provided, and which is coupled to the mass body and the piezoresistive element so that a force or movement introduced by the mass body into the lever element is transmitted by the lever element using a conversion factor to the piezoresistive element.

2. The yaw-rate sensor according to claim 1, wherein the drive unit sets the mass body into movement electrostatically, magnetically, mechanically, optically, chemically, piezoelectrically, and/or thermally.

3. The yaw-rate sensor according to claim 1, wherein the drive unit and the detection unit are configured in such a way that a drive voltage of the drive unit is separated with respect to time and/or by differing frequency modulation from a measuring current of the detection unit.

4. A yaw-rate sensor for determining a Coriolis force, comprising:

a semiconductor substrate;

a mass body mounted so it is movable over the semiconductor substrate;

a drive unit for setting the mass body into an oscillating movement; and

a detection unit for determining a deflection of the mass body caused by the Coriolis force, the detection unit including a piezoresistive element, wherein the mass body includes two mass elements, which are set into movements in opposite directions by the drive unit, and a piezoresistive element is situated between the mass elements and is operationally linked to the mass elements in such a way that deflections of the mass elements caused by the Coriolis force act in opposite directions on the piezoresistive element.

5. The yaw-rate sensor according to claim 4, wherein a lever element is associated with each mass element, and the piezoresistive element is situated between the lever elements.

6. The yaw-rate sensor according to claim 5, wherein at least one lever element has an isolating element for electrical isolation, so that a part of the lever element and the piezoelectric element are electrically isolated from the semiconductor substrate.

7. The yaw-rate sensor according to claim 4, wherein a lever element is associated with each mass element, the lever elements are coupled to one another using a compensating spring, and the piezoresistive element is situated between one of the lever elements and a suspension point on the semiconductor substrate.

8. The yaw-rate sensor according to claim 7, wherein a second piezoresistive element, which is situated between a second lever element and a second suspension point, is provided and an electrical subtraction unit is provided, in order to compare signals provided by the piezoresistive elements.