Sensor system including two inertial sensors

• US 9,817,021 B2
• Filed: 06/24/2014
• Issued: 11/14/2017
• Est. Priority Date: 06/25/2013
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Meisel, Daniel Christoph, Kathmann, Thomas
• Primary Examiner(s): Patel, Harshad R
• Assistant Examiner(s): Nath, Suman K
• Application Number:
  US14/312,978
• Publication Number:
  US 20140373625A1
• Time in Patent Office: 1,239 Days
• Field of Search: 73493, 7351432, 7350404
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/18 in two or more dimensions

Abstract

A sensor system is described as including at least two micromechanical inertial sensors, which are movably connected to a substrate, each inertial sensor including a functional layer, the functional layers of the two inertial sensors varying in thickness, and the two inertial sensors being situated next to one another on the substrate.

Claims

1. A sensor system, comprising:

a substrate;

at least two micromechanical inertial sensors that are movably connected to the substrate, wherein;

each inertial sensor includes a functional layer,

the functional layers of the at least two inertial sensors vary in thickness along a direction perpendicular to the substrate,

the at least two inertial sensors are situated next to one another on the substrate,

a difference in a layer thickness of the at least two inertial sensors is at least 1 μ

m; and

a plurality of fixed electrodes that extend perpendicular to the substrate, wherein;

a first fixed electrode located directly below a first inertial sensor along the direction perpendicular to the substrate extends to a first height from the substrate along the direction perpendicular to the substrate;

a second fixed electrode located directly below a second inertial sensor along the direction perpendicular to the substrate extends to a second height from the substrate along the direction perpendicular to the substrate;

the first height and the second height are different;

the first fixed electrode extends up from the substrate to the first height towards the functional layer of the first inertial sensor; and

the second fixed electrode extends up from the substrate to the second height towards the functional layer of the second inertial sensor.

2. The sensor system as recited in claim 1, wherein at least one of the inertial sensors is an acceleration sensor and another of the inertial sensors is a yaw rate sensor.

3. The sensor system as recited in claim 1, wherein one of:

both inertial sensors are acceleration sensors, and

both inertial sensors are yaw rate sensors.

4. The sensor system as recited in claim 1, further comprising:

a plurality of spring elements, wherein;

one of the inertial sensors includes a frame which includes a plurality of finger structures,

the frame is formed from the functional layer, and

the frame is connected to the substrate via the spring elements.

5. The sensor system as recited in claim 1, further comprising:

a spring, wherein;

a third inertial sensor includes a rocker mass,

the rocker mass is formed from the functional layer, and

the rocker mass is fixed to the substrate via the spring.

6. The sensor system as recited in claim 1, further comprising:

a plurality of springs, wherein;

a third inertial sensor includes a trampoline mass formed from the functional layer, and

the trampoline mass is fixed to the substrate via the springs.

7. The sensor system as recited in claim 1, wherein the functional layer of at least one of the inertial sensors has a thickness of between 0.5 μ

m and 100 μ

m.

8. The sensor system as recited in claim 7, wherein:

the functional layer of a first one of the inertial sensors has a thickness between 0.5 μ

m and 5 μ

m,

the functional layer of a second one of the inertial sensors has a thickness between 5 μ

m and 50 μ

m, and

the functional layer of a third one of the inertial sensors has a thickness between 5 μ

m and 50 μ

m.

9. The sensor system as recited in claim 8, wherein:

the first one of the inertial sensors is a first acceleration sensor,

the second one of the inertial sensors is a second acceleration sensor, and

the third one of the inertial sensors is a yaw rate sensor.

10. The sensor system as recited in claim 9, wherein:

the first inertial sensor detects an acceleration in a z-direction perpendicular to the substrate, and

the second inertial sensor detects an acceleration in an x-direction parallel to the substrate.

11. The sensor system as recited in claim 1, wherein the functional layer of a first of the inertial sensors has a thickness of between 5 μ

m and 50 μ

m.

12. The sensor system as recited in claim 11, wherein the functional layer of a second of the inertial sensors has a thickness of between 0.5 μ

m and 5 μ

m.

13. The sensor system as recited in claim 1, wherein the functional layers of the inertial sensors is an epitaxial semiconductor layer.

14. The sensor system as recited in claim 1, further comprising:

a plurality of gas-tight cavities within each of which a gas pressure predominates that differs from those of the other gas-tight cavities, wherein the inertial sensors are each situated respectively in a corresponding one of the gas-tight cavities.

15. The sensor system as recited in claim 1, wherein the functional layer of at least one of the inertial sensors one of includes at least polysilicon and is formed from polysilicon.

16. The sensor system as recited in claim 1, further comprising:

a connection element, wherein the functional layers of at least two of the inertial sensors are connected to one another via the connection element.