Triaxial acceleration sensor

• US 8,333,113 B2
• Filed: 07/17/2009
• Issued: 12/18/2012
• Est. Priority Date: 07/30/2008
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Classen, Johannes, Tebje, Lars
• Primary Examiner(s): Kwok, Helen C.
• Application Number:
  US12/505,116
• Publication Number:
  US 20100024554A1
• Time in Patent Office: 1,250 Days
• Field of Search: 735/143.2, 735/143.6, 735/143.8, 735/142.9, 735/141.6, 735/10, 735/11
• US Class Current: 73/514.32
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G01P 2015/0814 for translational movement of the mass, e.g. shuttle type
• CPC Class Codes: G01P 2015/0831 the mass being of the paddle type having the pivot axis between the longitudinal ends of the mass, e.g. see-saw configuration

Abstract

An acceleration sensor includes a substrate and a first mass element, which is connected to the substrate in such a way that the first mass element is rotatable about an axis, the first mass element being connected to a second mass element in such a way that the second mass element is movable along a first direction parallel to the axis, and the first mass element being connected to a third mass element in such a way that the third mass element is movable along a second direction perpendicular to the axis.

Claims

1. An acceleration sensor comprising:

a substrate;

a first mass element structured as an external frame enclosing at least three area sections, the external frame connected to the substrate in a centrally located first of the at least three area sections in such a way that the external frame is rotatable about an axis;

a second mass element situated in a second of the at least three area sections and connected to the second area section of the external frame in such a way that the second mass element is movable along a first direction parallel to the axis; and

a third mass element situated in a third of the at least tree area sections and connected to the third area section of the external frame in such a way that the third mass element is movable along a second direction perpendicular to the axis.

2. The acceleration sensor according to claim 1, wherein the first mass element is designed asymmetrically with respect to the axis.

3. The acceleration sensor according to claim 1, wherein the substrate is a silicon substrate.

4. The acceleration sensor according to claim 1, further comprising at least one detection electrode fixedly connected to the substrate and situated opposite the first mass element, which allows detection of a rotation of the first mass element about the axis.

5. The acceleration sensor according to claim 4, wherein at least two detection electrodes are provided, the detection electrodes allowing a differential evaluation of a rotation of the first mass element about the axis.

6. The acceleration sensor according to claim 5, wherein the at least two detection electrodes are situated on each of two sides of the axis, the at least two detection electrodes being symmetrical to each other with respect to the axis.

7. The acceleration sensor according to claim 1, wherein the first mass element has a frame, the second mass element being connected to the frame via at least one bending spring extensible in the first direction.

8. The acceleration sensor according to claim 1, wherein the first mass element has a frame, the third mass element being connected to the frame via at least one bending spring extensible in the second direction.

9. The acceleration sensor according to claim 1, wherein the second mass element has first finger electrodes, with first substrate electrodes fixedly connected to the substrate being situated opposite thereto, the first finger electrodes and the first substrate electrodes allowing a detection of a deflection of the second mass element in the first direction.

10. The acceleration sensor according to claim 1, wherein the third mass element has second finger electrodes, with second substrate electrodes fixedly connected to the substrate being situated opposite thereto, the second finger electrodes and the second substrate electrodes allowing a detection of a deflection of the third mass element in the second direction.