Acceleration sensor

• US 5,574,222 A
• Filed: 08/04/1995
• Issued: 11/12/1996
• Est. Priority Date: 09/02/1994
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Offenberg, Michael
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): MOLLER, RICHARD ALAN
• Application Number:
  US08/511,184
• Time in Patent Office: 466 Days
• Field of Search: 73/514.32, 361/283.3, 310/309, 324/725
• US Class Current: 73/514.32
• CPC Class Codes: G01P 15/125 by capacitive pick-up

Abstract

In an acceleration sensor having a multiplicity of movable electrodes, a first group of fixed electrodes is arranged on one side of the movable electrodes and a second group of fixed electrodes is arranged on the other side of the movable electrodes. The fixed electrodes of the first group are suspended from a connecting beam and are connected in parallel electrically by the latter. The fixed electrodes of the second group are anchored individually on the substrate and are connected in parallel electrically by means of a connecting conductor track.

Claims

1. An acceleration sensor comprising:

a substrate;

a bending element mounted to the substrate;

a seismic mass suspended from the bending element;

a plurality of movable electrodes suspended from the seismic mass and adapted to move with respect to the substrate in response to an acceleration;

a connecting beam mounted on the substrate;

a first group of fixed electrodes suspended from the connecting beam, the first group including a plurality of fixed electrodes, each of the fixed electrodes of the first group arranged on one side of a respective one of the movable electrodes; and

a second group of fixed electrodes, each of the fixed electrodes of the second group individually mounted on the substrate and arranged on another side of the respective movable electrode opposite the side of the respective movable electrode on which a respective fixed electrode of the first group is arranged;

wherein the first and second groups of fixed electrodes and the movable electrodes form at least one plate capacitor.

2. The acceleration sensor according to claim 1, wherein each of the movable electrodes is between one of the first group of fixed electrodes and one of the second group of fixed electrodes, thereby forming one of the at least one plate capacitor.

3. The acceleration sensor according to claim 2, wherein a quantity of plate capacitors corresponds to a quantity of each of the movable electrodes, first group of fixed electrodes, and second group of fixed electrodes.

4. The acceleration sensor according to claim 1, further comprising a connecting conductor track electrically coupling the second group of fixed electrodes in parallel, and wherein

the first group of fixed electrodes are electrically coupled in parallel by the connecting beam.

5. The acceleration sensor according to claim 4, further comprising at least one conductor track for connecting the connecting beam and the connecting conductor track.

6. The acceleration sensor according to claim 5, wherein the connection of the connecting beam and the connecting conductor track is symmetrical relative to the first and second groups of fixed electrodes.