Yaw rate sensor

• US 8,695,425 B2
• Filed: 12/03/2009
• Issued: 04/15/2014
• Est. Priority Date: 01/21/2009
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Classen, Johannes
• Primary Examiner(s): KWOK, HELEN C
• Application Number:
  US13/138,102
• Publication Number:
  US 20120006115A1
• Time in Patent Office: 1,594 Days
• Field of Search: 735/041.2, 735/041.4, 735/041.6, 735/040.2, 735/040.4
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5747 each sensing mass being connected to a driving mass, e.g. driving frames

Abstract

A yaw rate sensor includes a substrate having a substrate surface, a first movable element, which is disposed above the substrate surface and has a drive frame and a first detection mass, a first electrode, which is disposed at a distance underneath the first detection mass and connected to the substrate surface, and a second electrode which is disposed at a distance above the first detection mass and connected to the substrate surface. The drive frame is connected to the substrate via at least one drive spring, the detection mass is connected to the drive frame via at least one detection spring, and the first movable element is excitable to a drive oscillation parallel to the substrate surface, and the first detection mass is deflectable perpendicular to the substrate surface.

Claims

1. A yaw rate sensor comprising:

a substrate having a substrate surface,

a first movable element, which is disposed above the substrate surface and includes a drive frame and a first detection mass,

a first electrode, which is disposed at a distance underneath the first detection mass and connected to the substrate surface, and a second electrode, which is disposed at a distance above the first detection mass and connected to the substrate surface,

the drive frame being connected to the substrate via at least one drive spring,

the detection mass being connected to the drive frame via at least one detection spring,

the first movable element being excitable to a drive oscillation parallel to the substrate surface, and

the first detection mass being deflectable perpendicular to the substrate surface;

wherein the first movable element has at least one opening, the second electrode being connected to the substrate surface through the opening at an affixation point.

2. The yaw rate sensor as recited in claim 1, wherein a circuit track plane, a first functional plane, and a second functional plane are layered on top of one another, the circuit track plane is connected to the substrate surface, the drive frame is disposed in the first functional plane and in the second functional plane, the first detection mass is disposed at least partially in the first functional plane, the first electrode is situated in the circuit track plane, and the second electrode is situated in the second functional plane.

3. The yaw rate sensor as recited in claim 1, wherein the yaw rate sensor has a second movable element, which includes a second detection mass, the first and the second detection mass being connected to each other via a coupling spring, the first and the second movable element being excitable to a coupled drive oscillation parallel to the substrate surface.

4. The yaw rate sensor as recited in claim 2, wherein the yaw rate sensor has a second movable element, which includes a second detection mass, the first and the second detection mass being connected to each other via a coupling spring, the first and the second movable element being excitable to a coupled drive oscillation parallel to the substrate surface.

5. The yaw rate sensor as recited in claim 3, wherein the first and the second movable element are excitable to a coupled drive oscillation producing an anti-parallel deflection of the first and the second movable element.

6. The yaw rate sensor as recited in claim 4, wherein the first and the second movable element are excitable to a coupled drive oscillation producing an anti-parallel deflection of the first and the second movable element.

7. The yaw rate sensor as recited in claim 2, wherein the first movable element has a stabilizing frame, which is disposed at least partially in the second functional plane.

8. The yaw rate sensor as recited in claim 7, wherein the first movable element has a trough shape with a floor disposed in the first functional plane and an edge, formed by the stabilizing frame, in the first functional plane and the second functional plane.

9. The yaw rate sensor as recited in claim 1, wherein at least one drive comb structure is provided in order to excite the first movable element to the drive oscillation.

10. The yaw rate sensor as recited in claim 1, wherein the first movable element is connected to the substrate surface via at least one external spring.

11. The yaw rate sensor as recited in claim 2, wherein the first functional plane and the second functional plane are made of conductive silicon.

12. The yaw rate sensor as recited in claim 1, wherein at least one further electrode is disposed underneath or above the first detection mass.

13. The yaw rate sensor as recited in claim 12, wherein the at least one further electrode is designed for an electrostatic positive feedback of the first detection mass, for a closed-loop position control of the first detection mass or a quadrature compensation.

14. The yaw rate sensor as recited in claim 1, wherein the yaw rate sensor is connected to an evaluation circuit, which is designed to infer a deflection of the first detection mass perpendicular to the substrate surface from a change in capacitances between the first detection mass and the first and second electrodes, and to infer a yaw rate acting on the yaw rate sensor from the deflection of the first detection mass.