Acceleration sensor

• US 5,959,208 A
• Filed: 09/18/1997
• Issued: 09/28/1999
• Est. Priority Date: 02/10/1995
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Lutz, Markus, Schubert, Dietrich, Offenberg, Michael, Muenzel, Horst, Heyers, Klaus, Boehringer, Alexandra
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): MOLLER, RICHARD ALAN
• Application Number:
  US08/933,446
• Time in Patent Office: 740 Days
• Field of Search: 73/514.01, 73/514.02, 73/514.18, 73/514.32, 73/514.35, 73/514.36, 73/514.38, 73/514.21, 73/514.24, 73/504.12, 73/504.1 4
• US Class Current: 73/514.32
• 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 3/48 by measuring frequency of generated current or voltage in general G01R23/00
• CPC Class Codes: Y10S 148/135 Removal of substrate
• CPC Class Codes: Y10S 148/159 Strain gauges

Abstract

An acceleration sensor is composed of a three layer system. The acceleration sensor and conductor tracks are patterned out of the third layer. The conductor tracks are electrically isolated from other regions of the third layer by recesses and electrically insulated from a first layer by a second electrically insulating layer. In this manner, a simple electrical contacting is achieved, which is configured out of a three-layer system.

Claims

1. An acceleration sensor, comprising:

a first layer forming a support plate;

a second insulating layer applied to the first layer;

a third layer applied to the second layer and defining a deflectable mass, the deflectable mass being responsive to a force; and

at least one conductor track patterned out of the third layer and leading to a connection point, the at least one conductor track being electrically insulated from the first layer by the second layer and being electrically isolated from the third layer by at least one recess.

2. The acceleration sensor according to claim 1, wherein the first layer, the second layer and the third layer are formed using a silicon-on-insulator layer construction.

3. The acceleration sensor according to claim 1, wherein the deflectable mass includes a comb structure, the deflectable mass being deflected in a direction parallel to a surface of the third layer. 4.

4. The acceleration sensor according to claim 3, wherein the comb structure includes:

a first elongated frame element having a set of first plates arranged in a direction normal to a direction of the first frame element;

a second frame element arranged on one side of the first frame element, the second frame element being arranged in a direction parallel to the first frame element and having a set of second plates aligned in a direction normal to a direction of the second frame element and towards the first frame element;

a third frame element arranged on another side of the first elongated frame element, the third frame element being arranged in a direction parallel to the first frame element and having a set of third plates aligned in a direction normal to a direction of the second frame element and towards the first frame element, the sets of second and third plates being arranged parallel to the set of first plates; and

wherein, when the deflectable mass is deflected, a distance between the set of first plates and one of the set of second plates and the set of third plates increases, while a distance between the set of first plates and one of the set of second plates and the set of third plates decreases, each of the set of second plates and the set of third plates being separately connected to a signal line, the deflectable mass also being connected to the signal line, two measuring signals being determined using a capacitive measurement.

5. The acceleration sensor according to claim 1, wherein a conductive layer is provided on the at least one conductor track.

6. The acceleration sensor according to claim 1, wherein the acceleration sensor is provided on a vibrational system of a rate-of-rotation sensor wherein the rate-of-rotation sensor includes a frame, and wherein the rate-of-rotation sensor is composed of the first layer, the second layer and the third layer, the at least one conductor track being connected to the frame of the rate-of-rotation sensor, the at least one conductor track being electrically insulated from the first layer by the second layer, and electrically isolated from the third layer by a recess.