ROTARY DISK GYROSCOPE

• US 20130086985A1
• Filed: 10/05/2011
• Published: 04/11/2013
• Est. Priority Date: 10/05/2011
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Lin, Yizhen
• Granted Patent: US 8,448,513 B2
• Time in Patent Office: Days
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure

Abstract

A rotary disk gyroscope (20) includes a drive mass (28) and a sense mass (32). The sense mass (32) includes a cutout region (46, 48) located proximate an axis of rotation (40). Torsion springs (38), located in the cutout region (46, 48), connect the sense mass (32) to the drive mass (28). The torsion springs (38) enable the sense mass (32) to rotate about the axis of rotation (40) in response to an angular velocity of the gyroscope (20). Spring anchorage structures (30) are also positioned in the cutout region (46, 48), and flexibly couple the drive mass (28) to the substrate (22). In addition, a drive system (68) resides in the cutout region (46, 48) and actuates the drive mass (28) to move with an oscillatory motion. In a dual axis configuration, the gyroscope (20) further includes a rectangular-shaped second sense mass (36) surrounding the disk-shaped drive mass (28).

Claims

1. A gyroscope comprising:

a substrate having a surface;

a drive mass flexibly coupled to said substrate surface, said drive mass having a central opening;

a sense mass residing in said central opening and configured to rotate about an axis of rotation, said sense mass including a cutout region proximate said axis of rotation;

torsion springs connecting said sense mass to said drive mass; and

a drive system at least partially residing in said cutout region for actuating said drive mass to move with an oscillatory motion.

2. A gyroscope as claimed in claim 1 wherein said cutout region extends inwardly as a notched region from an outer perimeter of said sense mass.

3. A gyroscope as claimed in claim 1 wherein said axis of rotation extends through said cutout region.

4. A gyroscope as claimed in claim 1 wherein said cutout region includes first and second edges oriented in a radial direction and extending on opposing sides of said axis of rotation.

5. A gyroscope as claimed in claim 1 wherein at least one of said torsion springs partially resides in said cutout region and is aligned with said axis of rotation.

6. A gyroscope as claimed in claim 1 wherein said cutout region is a first cutout region, and said sense mass further comprises a second cutout region proximate said axis of rotation, said first and second cutout regions being substantially symmetrically positioned in said sense mass relative to one another on opposing sides of an axis that is perpendicular to said axis of rotation.

7. A gyroscope as claimed in claim 6 wherein said drive system comprises:

a first set of drive elements residing in said first cutout region; and

a second set of drive elements residing in said second cutout region, said second set of drive elements operating cooperatively with said first set of drive elements to move said drive mass with said oscillatory motion.

8. A gyroscope as claimed in claim 1 wherein an inner perimeter of said drive mass defines said central opening, and said drive system comprises:

first comb fingers extending from said inner perimeter of said drive mass into said cutout region; and

second comb fingers fixed to said surface of said substrate, said second comb fingers being spaced apart from and positioned in an alternating arrangement with said first comb fingers.

9. A gyroscope as claimed in claim 8 wherein said first and second comb fingers are located in said cutout region adjacent to at least one of said torsion springs.

10. A gyroscope as claimed in claim 1 wherein an inner perimeter of said drive mass defines said central opening, and said gyroscope further comprises:

anchors coupled to said surface of said substrate underlying said cutout region; and

spring elements configured to fasten said drive mass to said anchors, one each of said spring elements extending between said inner perimeter of said drive mass and one each of said anchors to form multiple spring anchorage structures.

11. A gyroscope as claimed in claim 1 wherein said sense mass is a first sense mass, said torsion springs are first torsion springs, and said gyroscope further comprises:

a second sense mass surrounding said drive mass; and

second torsion springs connecting said second sense mass to said drive mass.

12. A gyroscope as claimed in claim 11 wherein:

said drive mass is a ring-shaped structure; and

said second sense mass is rectangular-shaped structure, said second sense mass having a central opening configured to accommodate said ring-shaped structure of said drive mass.

13. A gyroscope comprising:

a substrate having a surface;

a drive mass flexibly coupled to said substrate surface, said drive mass having a central opening;

a sense mass residing in said central opening and configured to rotate about an axis of rotation, said sense mass including first and second cutout regions proximate said axis of rotation, said first and second cutout regions being substantially symmetrically positioned in said sense mass relative to one another on opposing sides of an axis that is perpendicular to said axis of rotation;

a first torsion spring partially residing in said first cutout region;

a second torsion spring partially residing in said second cutout region, said first and second torsion springs connecting said sense mass to said drive mass, each of said first and second torsions springs being aligned with said axis of rotation; and

a drive system at least partially residing in at least one of said first and second cutout regions for actuating said drive mass to move with an oscillatory motion.

14. A gyroscope as claimed in claim 13 further comprising:

anchors coupled to said surface of said substrate underlying each of said first and second cutout regions;

spring elements configured to fasten said drive mass to said anchors, one each of said spring elements extending between an inner perimeter of said drive mass and one each of said anchors to form multiple spring anchorage structures.

15. A gyroscope as claimed in claim 13 wherein said drive system comprises:

a first set of drive elements residing in said first cutout region; and

a second set of drive elements residing in said second cutout region, said second set of drive elements operating cooperatively with said first set of drive elements to move said drive mass with said oscillatory motion.

16. A gyroscope as claimed in claim 15 wherein each of said first and second set of drive elements comprises:

first comb fingers extending from an inner perimeter of said drive mass into one said first and second cutout regions; and

second comb fingers fixed to said surface of said substrate, said second comb fingers being spaced apart from and positioned in an alternating arrangement with said first comb fingers.

17. A gyroscope comprising:

a substrate having a surface;

a drive mass flexibly coupled to said substrate surface, said drive mass having a central opening;

a sense mass residing in said central opening and configured to rotate about an axis of rotation, said sense mass including first and second cutout regions proximate said axis of rotation, each of said first and second cutout regions extending inwardly as a notched region from an outer perimeter of said sense mass;

a first torsion spring partially residing in said first cutout region;

a second torsion spring partially residing in said second cutout region, said first and second torsion springs connecting said sense mass to said drive mass, and said first and second torsion springs being aligned with said axis of rotation; and

a drive system at least partially residing in said first and second cutout regions for actuating said drive mass to move with an oscillatory motion.

18. A gyroscope as claimed in claim 17 wherein an inner perimeter of said drive mass defines said central opening, and said drive system comprises:

first comb fingers extending from said inner perimeter of said drive mass into one of said first and second cutout regions; and

second comb fingers fixed to said surface of said substrate, said second comb fingers being spaced apart from and positioned in an alternating arrangement with said first comb fingers.

19. A gyroscope as claimed in claim 18 further comprising:

anchors coupled to said surface of said substrate underlying said first and second cutout regions; and

spring elements configured to fasten said drive mass to said anchors, one each of said spring elements extending between said inner perimeter of said drive mass and one each of said anchors to form multiple spring anchorage structures co-located with said drive system and said first and second torsion springs in said first and second cutout regions.

20. A gyroscope as claimed in claim 17 wherein said sense mass is a first sense mass and said gyroscope further comprises:

a second sense mass surrounding said drive mass; and

third torsion springs connecting said second sense mass to said drive mass, said drive mass being a ring-shaped structure, said second sense mass having a central opening configured to accommodate said ring-shaped structure of said drive mass, and said second sense mass being a rectangular-shaped structure.