Micromechanical system for detecting an acceleration

• US 8,783,108 B2
• Filed: 09/07/2010
• Issued: 07/22/2014
• Est. Priority Date: 09/08/2009
• Status: Active Grant

• Current Assignee: Robert Bosch Cmbh
• Original Assignee: Robert Bosch GmbH
• Inventors: Classen, Johannes
• Primary Examiner(s): KWOK, HELEN C
• Application Number:
  US12/876,559
• Publication Number:
  US 20110056297A1
• Time in Patent Office: 1,414 Days
• Field of Search: 735/143.2, 735/143.6, 735/143.8, 735/142.4, 735/141.8
• US Class Current: 73/514.32
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• 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

A micromechanical system for detecting an acceleration includes a substrate, a rocker-like mass structure having a first lever arm and a diametrically opposed second lever arm, the lever arms being situated tiltably at a distance to the substrate and about an axis of rotation to the substrate, and first and second electrodes being provided on the substrate. Each electrode is diametrically opposed to a lever arm and each lever arm includes a section extending from the axis of rotation which is located between the electrodes above an intermediate space. The two sections have different masses.

Claims

1. A micromechanical system for detecting an acceleration, comprising:

a substrate;

a rocker-like mass structure having a first lever arm and a diametrically opposed second lever arm, which are situated tiltably at a distance in relation to the substrate and about an axis of rotation to the substrate; and

first and second electrodes situated on the substrate, each electrode being diametrically opposed to a lever arm, wherein the two electrodes are arranged in mirror symmetry with respect to the axis of rotation,

wherein each lever arm includes a section extending from the axis of rotation, the two sections having varying masses that lie above an intermediate space between the electrodes and each section includes an end section having equal masses, such that the first electrode is located under the end section of the first lever arm and the second electrode is located under the end section of the second lever arm, each at a distance farther from the axis of rotation than the two sections having varying masses.

2. The system according to claim 1, wherein one of the sections has a greater recess than the other section.

3. The system according to claim 1, wherein one of the sections includes an additional mass.

4. The system according to claim 1, wherein both lever arms are at an equal distance from the axis of rotation.

5. The system according to claim 1, further comprising an additional electrode situated on the substrate in the intermediate space between the electrodes.

6. The system according to claim 5, wherein an underside of the mass structure facing the substrate has a cover layer which is in mirror symmetry with respect to the axis of rotation.

7. The system according to claim 6, further comprising first, second and third functional layers, the electrodes being a component of the first functional layer, the cover layer being a component of the second functional layer, and the mass structure being a component of the third functional layer.

8. The system according to claim 1, wherein the mass structure is connected to the substrate via a fastening structure, the fastening structure including a torsion spring which acts counter to a tipping of the mass structure toward the substrate.

9. The system according to claim 8, wherein the fastening structure is connected to the substrate.