INTEGRATED MEMS 3D MULTI-SENSOR

• US 20090139330A1
• Filed: 11/29/2007
• Published: 06/04/2009
• Est. Priority Date: 11/29/2007
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Cobianu, Cornel P., Georgescu, Ion, Pavelescu, Ioan, Guran, Dana Elena
• Granted Patent: US 7,784,344 B2
• Time in Patent Office: Days
• US Class Current: 73/514.320
• CPC Class Codes: G01D 21/02 Measuring two or more variables by means not covered by a single other subclass
• 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 2015/082 for two degrees of freedom of movement of a single mass

Abstract

Apparatus, methods, and systems for sensing acceleration and magnetic fields in all three axes from a first capacitive bridge sensor having a first proof mass; and a second capacitive bridge sensor having a second proof mass located within the first proof mass. The second proof mass is coupled to the first proof mass by springs that permit movement in the second axis. The of sense the remaining axis of interest may be done by a third and fourth capacitive bridge configured similar to that of the first and second capacitive bridge sensors. The third and fourth capacitive bridge sensors may be oriented 90 degrees off of the first and second capacitive bridge. An alternative is to locate a third capacitive bridge within the second proof mass.

Claims

1. An apparatus comprising:

a first capacitive bridge sensor having a first proof mass supported by a first set of springs to permit movement in a first axis; and

a second capacitive bridge sensor having a second proof mass located within the first proof mass, the second proof mass supported by a second set of springs to permit movement in a second axis.

2. The apparatus of claim 1, wherein the second set of springs is coupled to the first proof mass.

3. The apparatus of claim 2, wherein the first capacitive bridge sensor is adapted to sense acceleration in a first axis and the second capacitive bridge sensor is adapted to sense acceleration in a second axis.

4. The apparatus of claim 2, wherein the first capacitive bridge sensor is adapted to sense a magnetic field in a first axis and the second capacitive bridge sensor is adapted to sense a magnetic field in a second axis.

5. The apparatus of claim 3, wherein the first capacitive bridge sensor is adapted to sense a magnetic field in a second axis and the second capacitive bridge sensor is adapted to sense a magnetic field in a first axis.

6. An apparatus comprising,

an external capacitive bridge sensor having a first proof mass for sensing a first parameter in a first axis;

an internal capacitive bridge sensor having a second proof mass suspended within the first proof mass for sensing the parameter in a second axis; and

a third capacitive bridge sensor having a third proof mass for sensing the parameter in a third axis.

7. The apparatus of claim 6, further comprising a second internal capacitive bridge sensor having a fourth proof mass suspended within the third proof mass.

8. The apparatus of claim 6, wherein the parameter is acceleration.

9. The apparatus of claim 6, wherein the third proof mass is suspended within the second proof mass.

10. The apparatus of claim 6, wherein the parameter is magnetic field.

11. The apparatus of claim 10, wherein a current passes through the first, second or third proof mass when detecting a magnetic field.

12. The apparatus of claim 8, wherein the external capacitive bridge sensor is adapted to sense a first magnetic field in the second axis;

the internal capacitive bridge sensor a second magnetic field in the first axis; and

a second internal capacitive bridge sensor having a fourth proof mass suspended within the third proof mass for sensing a third magnetic field in a third axis.

13. The apparatus of claim 6, further comprising an application-specific integrated chip coupled to the capacitive bridge sensors.

14. The apparatus of claim 6, further comprising an application-specific integrated circuit coupled to the capacitive bridge sensors formed on a chip.

15. The apparatus of claim 13, further comprising a navigation system, wherein an application-specific integrated chip provides an output to the navigation system.

16. A method comprising:

sensing acceleration in a first axis with a first proof mass;

sensing acceleration in a second axis with a second proof mass, the second proof mass being located within the first proof mass; and

sensing acceleration in a third axis with a third proof mass.

17. The method of claim 16 further comprising:

sensing a first magnetic field in the second axis with the first proof mass;

sensing a second magnetic field in the first axis with the second proof mass, the second proof mass being located within the first proof mass; and

sensing a third magnetic field in the third axis with a fourth proof mass.

18. The method of claim 17 further comprising:

determining a change in location from the sensed acceleration in the first axis, the second axis and the third axis.

19. The method of claim 17 further comprising:

determining a location from the sensed first, second, and third magnetic fields.

20. The method of claim 19, correcting the location by comparing the sensed first, second and third magnetic fields, with the sensed acceleration in the first axis, the second axis, and the third axis.