MICROMECHANICAL STRUCTURES

• US 20100192690A1
• Filed: 01/06/2010
• Published: 08/05/2010
• Est. Priority Date: 02/04/2009
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: CLASSEN, Johannes, Gauger, Christoph
• Granted Patent: US 8,726,731 B2
• Time in Patent Office: Days
• 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 micromechanical structure including a substrate having a main plane of extension, and including a first seismic mass, the first seismic mass including a grid structure made of intersecting first mass lines and the first seismic mass being flexibly secured with the aid of first bending-spring elements, and moreover, a first line width of the first mass lines parallel to the main plane of extension being between 20 and 50 percent of a further first line width of the first bending-spring elements parallel to the main plane of extension.

Claims

1. A micromechanical structure comprising:

a substrate having a main plane of extension; and

a first seismic mass including a grid structure made of intersecting first mass lines, the first mass lines including first mass lines parallel to the main plane of extension and the first seismic mass being flexibly secured by first bending-spring elements, the first bending-spring elements including first bending-spring elements parallel to the main plane of extension, wherein a first line width of the first mass lines parallel to the main plane of extension is between 20 and 50 percent of a further first line width of the first bending-spring elements parallel to the main plane of extension.

2. The micromechanical structure as recited in claim 1, wherein the first line width is between 25 and 40 percent of the further first line width.

3. The micromechanical structure as recited in claim 3, wherein the first line width is between 30 and 36 of the further first line width.

4. The micromechanical structure as recited in claim 3, wherein the first line width is 33 percent of the further first line width.

5. A yaw-rate sensor, comprising:

a substrate having a main plane of extension;

a first sensing-mass element and a second sensing-mass element, the first sensing-mass element being excitable by a first driving element into a first oscillation parallel to the main plane of extension, the second sensing-mass element being excitable by a second driving element into a second oscillation anti-parallel to the first oscillation, a first Coriolis displacement of the first sensing-mass element along a third direction perpendicular to the main plane of extension being detectable by a first sensing element, a second Coriolis displacement of the second sensing-mass element along the third direction being detectable by a second sensing means, and the first and second sensing-mass elements being coupled to each other by a first coupling element, wherein the first sensing-mass element is a first rocker structure and the second sensing element is a second rocker structure.

6. The micromechanical structure as recited in claim 5, wherein one of the first or second rocker structure is secured to one of the first or second driving element by a torsion spring, a torsion axis of the torsion spring running parallel to one of the first or second direction, and the one of the first or second rocker structure having an asymmetrical mass distribution relative to the torsion axis.

7. The micromechanical structure as recited in claim 6, wherein the torsion spring is implemented as a ladder spring.

8. The micromechanical structure as recited in claim 7, wherein the torsion spring is implemented as a double-ladder spring.

9. The micromechanical structure as recited in claim 7, wherein the torsion spring is implemented as a multi-ladder spring.

10. The micromechanical structure as recited in claim 5, wherein the first and the second sensing-mass elements are attached to the substrate by second coupling elements, at least one of the first and the second coupling elements including bending springs which are meander-shaped.

11. The micromechanical structure as recited in claim 10, wherein the first and the second driving elements are attached to the substrate by third coupling elements, the third coupling elements including further bending springs which are meander-shaped.

12. The micromechanical structure as recited in claim 5, wherein the at least one of the first and the second coupling elements are more yielding with respect to a deformation at least one of:

i) parallel to the first oscillation, and ii) parallel to the third direction, than with respect to a deformation along a direction perpendicular to the first oscillation and to the third direction.

13. The micromechanical structure as recited in claim 5, wherein at least one of:

i) the first driving element surrounds the first sensing-mass element parallel to the main plane of extension, and ii) the second driving element surrounds the second sensing element parallel to the main plane of extension, at least one of the first and the second sensing elements having only one cutout for at least one of the first and the second coupling elements.

14. The micromechanical structure as recited in claim 5, wherein an outer periphery of the first sensing-mass element is symmetrical relative to the first torsion axis and an outer periphery of the second sensing-mass element is symmetrical relative to the second torsion axis.

15. The micromechanical structure as recited in claim 5, wherein at least one of the first and the second sensing-mass element includes a second seismic mass having second mass lines, the bending springs including second bending-spring elements, and a ratio between a second line width of the second mass lines and a further second line width of the second bending-spring elements being equal to a ratio between the first line width and the further first line width.

16. The micromechanical structure as recited in claim 11, wherein at least one of the first and the second driving element includes a third seismic mass having third mass lines, the further bending springs including third bending-spring elements, and a ratio between a third line width of the third mass lines and a further third line width of the third bending-spring elements being equal to a ratio between the first line width and the further first line width.