Acceleration sensor and method for producing an acceleration sensor

• US 9,709,596 B2
• Filed: 03/27/2014
• Issued: 07/18/2017
• Est. Priority Date: 05/02/2013
• Status: Expired due to Fees

• Current Assignee: Northrop Grumman Litef Gmbh (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Litef Gmbh (Northrop Grumman Corporation)
• Inventors: Geiger, Wolfram, Leinfelder, Peter, Bartholomeyczik, Julian
• Primary Examiner(s): Laballe, Clayton E
• Assistant Examiner(s): Hancock, Dennis
• Application Number:
  US14/888,432
• Publication Number:
  US 20160069928A1
• Time in Patent Office: 1,209 Days
• Field of Search: None
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 2015/0814 for translational movement of the mass, e.g. shuttle type
• CPC Class Codes: G01P 2015/0882 for providing damping of vibrations

Abstract

The invention relates to an acceleration sensor, comprising a substrate having a substrate surface and a sample mass that is movable relative to the substrate in a first direction (x) parallel to the substrate surface. The sample mass has a comb-like electrode that is movable together with the sample mass and has a plurality of teeth, which extend in the first direction (x). The acceleration sensor further comprises a counter-electrode fixedly connected to the substrate, which counter-electrode has a fixed comb-like electrode and wherein said fixed comb-like electrode has a plurality of teeth which extend in a direction opposite to the first direction (x). The teeth of the movable comb-like electrode engage with the teeth of the fixed comb-like electrode. The acceleration sensor further comprises a shielding electrode fixedly connected to the substrate and which is suitable for increasing a pneumatic damping of the sample mass during a deflection movement of the sample mass.

Claims

1. An acceleration sensor, comprising:

a substrate having a substrate surface;

a sample mass movable relative to the substrate along a positive deflection direction which is substantially parallel to the substrate surface, the sample mass comprising a movable comb-like electrode that is movable together with the sample mass, the movable comb-like electrode comprising a plurality of teeth which extend along the positive deflection direction;

a counter electrode fixedly connected to the substrate and comprising a fixed comb-like electrode, the fixed comb-like electrode comprising a plurality of teeth which extend along a direction opposite to the positive deflection direction, the teeth of the fixed comb-like electrode configured to engage with the teeth of the movable comb-like electrode; and

a shielding electrode fixedly connected to the substrate and configured to increase pneumatic damping of the sample mass during a deflection movement of the sample mass,

wherein the movable comb-like electrode further comprises a comb frontward side with a comb frontward surface that is substantially perpendicular to the positive deflection direction,

wherein the shielding electrode comprises a shielding electrode surface that is substantially parallel to the comb frontward surface,

wherein the comb frontward surface and the shielding electrode surface are opposite to each other,

wherein a distance between the comb frontward surface and the shielding electrode surface changes during a deflection movement of the sample mass, the change of the distance being suitable to increase pneumatic damping of the sample mass.

2. The acceleration sensor of claim 1, wherein the sample mass and the shielding electrode have the same electric potential.

3. The acceleration sensor of claim 1, wherein the counter electrode and the shielding electrode are connected to each other via an isolation layer.

4. The acceleration sensor of claim 1, wherein the sample mass comprises a further movable comb-like electrode that is movable together with the sample mass, wherein the further movable comb-like electrode comprises a plurality of teeth which extend along a direction opposite to the positive deflection direction, wherein the acceleration sensor comprises a further counter electrode fixedly connected to the substrate, wherein the further counter electrode comprises a further fixed comb-like electrode, wherein the further fixed comb-like electrode comprises a plurality of teeth which extend along the positive deflection direction, wherein the teeth of the further movable comb-like electrode are configured to engage with the teeth of the further fixed comb-like electrode, and wherein the acceleration sensor comprises a further shielding electrode fixedly connected to the substrate and configured to increase pneumatic damping of the sample mass during a deflection movement of the sample mass.

5. The acceleration sensor of claim 4, wherein the shielding electrode and the further shielding electrode are integrally connected to each other.

6. The acceleration sensor of claim 1, further comprising a spring element coupling the sample mass and the substrate to each other such that the sample mass can perform a deflection movement along the positive deflection direction and such that the sample mass is substantially rigidly supported in a direction perpendicular to the positive deflection direction and parallel to the substrate surface.

7. A method for producing an acceleration sensor, the method comprising:

forming a substrate having a substrate surface;

forming a sample mass that is movable relative to the substrate along a positive deflection direction which is substantially parallel to the substrate surface, the sample mass comprising a movable comb-like electrode that is movable together with the sample mass, the movable comb-like electrode comprising a plurality of teeth which extend along the positive deflection direction;

fixedly connecting a counter electrode to the substrate, the counter electrode comprising a fixed comb-like electrode, the fixed comb-like electrode comprising a plurality of teeth which extend along a direction opposite to the positive deflection direction, the teeth of the movable comb-like electrode configured to engage with the teeth of the fixed comb-like electrode; and

fixedly connecting a shielding electrode to the substrate, the shielding electrode configured to increase pneumatic damping of the sample mass during a deflection movement of the sample mass,

wherein the movable comb-like electrode comprises a comb frontward side with a comb frontward surface that is substantially perpendicular to the positive deflection direction,

wherein the shielding electrode comprises a shielding electrode surface that is substantially parallel to the comb frontward surface,

wherein the comb frontward surface and the shielding electrode surface are opposite to each other,

wherein a distance between the comb frontward surface and the shielding electrode surface changes during a deflection movement of the sample mass, the change of the distance being suitable to increase pneumatic damping of the sample mass.

8. The method of claim 7, further comprising:

adapting a gas pressure of the acceleration sensor to adjust optimal damping of the deflection movement of the sample mass.

9. The method of claim 7, further comprising:

selecting, at a predetermined gas pressure, a distance between the movable comb-like electrode and the shielding electrode of the acceleration sensor to adjust optimal damping of the deflection movement of the sample mass.