Angular velocity sensor with built-in limit stops

• US 5,721,377 A
• Filed: 07/22/1996
• Issued: 02/24/1998
• Est. Priority Date: 07/22/1995
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Lutz, Markus, Baumann, Helmut, Kurle, Juergen, Muenzel, Horst, Heyers, Klaus, Weiblen, Kurt
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US08/681,243
• Time in Patent Office: 582 Days
• Field of Search: 73/504.12, 73/504.14, 73/504.15, 73/504.16, 73/504.04, 73/514.32, 73/514.38, 73/514.16
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure
• CPC Class Codes: G01P 2015/0814 for translational movement of the mass, e.g. shuttle type

Abstract

In an angular velocity sensor, an acceleration sensor is arranged on a resonator formed of a multilayer substrate and attached to a resonating bar. The multilayer substrate includes a top silicon layer, an insulating sacrificial layer arranged below the top silicon layer, and a bottom silicon layer arranged below the insulating sacrificial layer. An excitor causes the resonator to vibrate while a limit stop, configured out of the multilayer substrate, limits the movement of the resonator.

Claims

1. An angular velocity sensor comprising:

a multilayer substrate including a top silicon layer, an insulating sacrificial layer arranged below the top silicon layer, and a bottom silicon layer arranged below the insulating sacrificial layer;

at least one resonating bar;

a resonator configured out of the multilayer substrate, the resonator being suspended on the resonating bar;

means for exciting the resonator to vibrate in a first direction;

an acceleration sensor arranged on the resonator; and

at least one limit stop configured out of the multilayer substrate, the limit stop limiting movement of the resonator.

2. The angular velocity sensor according to claim 1, wherein the at least one limit stop includes a plurality of limit stops.

3. The angular velocity sensor according to claim 1, wherein the at least one resonating bar includes a plurality of resonating bars.

4. The angular velocity sensor according to claim 2, further comprising a frame surrounding the resonator, and wherein:

the resonator vibrates in parallel to the multilayer substrate; and

the limit stops are arranged on the frame and on the resonator so as to limit movement of the resonator in parallel to the multilayer substrate.

5. The angular velocity sensor according to claim 1, wherein:

a thickness of the bottom silicon layer is decreased underneath the resonator; and

the limit stop is arranged below the resonator, the limit stop limiting movement of the resonator normal to the first direction.

6. The angular velocity sensor according to claim 5, wherein the limit stop is configured out of the bottom silicon layer.

7. The angular velocity sensor according to claim 1, further comprising:

a frame surrounding the resonator, the frame having a bottom layer; and

another plate secured to the bottom layer of the frame.

8. The angular velocity sensor according to claim 7, wherein the another plate is designed as a substrate board having the limit stop.

9. The angular velocity sensor according to claim 7, wherein the another plate is formed by a silicon wafer into which at least one recess is etched.

10. The angular velocity sensor according to claim 1, further comprising:

a frame surrounding the resonator, the frame having a bottom layer;

a silicon wafer; and

an insulation layer joining the bottom layer to the silicon wafer, the insulation layer being removed underneath the resonator and the resonating bar.

11. The angular velocity sensor according to claim 10, wherein the resonator has a bottom plate.

12. The angular velocity sensor according to claim 1, further comprising:

a frame surrounding the resonator and having a top side; and

a cover arranged on the top side of the frame.

13. The angular velocity sensor according to claim 1, wherein the first direction is parallel to the multilayer substrate, the acceleration sensor being adapted to measure an acceleration in a second direction which is parallel to the multilayer substrate and perpendicular to the first direction.