Horizontal and tuning fork vibratory microgyroscope

• US 6,918,298 B2
• Filed: 07/12/2004
• Issued: 07/19/2005
• Est. Priority Date: 12/24/2002
• Status: Expired due to Term

• Current Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Original Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Inventors: Park, Kyu Yeon
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US10/888,591
• Publication Number:
  US 20050109107A1
• Time in Patent Office: 372 Days
• Field of Search: 735/041.2, 735/041.6, 735/041.4, 735/041.1, 735/040.4
• US Class Current: 73/504.16
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces

Abstract

A horizontal and tuning fork vibratory microgyroscope detects angular velocity and angular acceleration of an inertial object when the inertial object is rotated, wherein resonance directions of the microgyroscope are on the same horizontal plane in both sensing and driving modes. The microgyroscope includes a substrate, an anchored pad unit, an outer elastic element unit, an outer frame, a sensing electrode unit, an inner elastic element unit including a plurality of inner elastic elements connected to the inside of the outer frame, an inner weighted element unit including a pair of first and second inner weighted elements each having a driven comb, and a driven electrode unit including a comb drive forming a comb structure.

Claims

1. A horizontal and tuning fork vibratory microgyroscope comprising:

a substrate having a plane structure in the horizontal direction defined by a X-axis and a Y-axis substantially perpendicular to the X-axis;

an anchored pad unit including a plurality of anchored pads anchored to the substrate;

an outer elastic element unit including a plurality of outer elastic elements connected at one end thereof to the anchored pads of the anchored pad unit, respectively;

an outer frame made substantially in the shape of a circle and connected to the other end of each of the plurality of outer elastic elements of the outer elastic element unit while the outer frame is spaced apart from the substrate by a predetermined gap, the outer frame including a driven electrode having driven electrode fingers forming a comb structure formed at the outside of the outer frame;

a driven electrode unit having driven electrode fingers forming a comb structure, the driven electrode fingers meshing with the driven electrode fingers of the outer frame while the driven electrode fingers are spaced apart from the driven electrode fingers by a predetermined gap, respectively;

an inner elastic element unit including a plurality of inner elastic elements connected at one end thereof to the inside of the outer frame;

an inner weighted element unit including a pair of first and second inner weighted elements having vibrating electrode fingers forming comb structures, respectively, the first and second inner weighted elements being connected to the other end of the plurality of inner elastic elements of the inner elastic element unit, respectively; and

a sensing electrode unit including first and second sensing electrodes having sensing electrode fingers forming comb structures, respectively, the sensing electrode fingers meshing with the vibrating electrode fingers of the first and second inner weighted elements of the inner weighted element unit while the sensing electrode fingers are spaced apart from the vibrating electrode fingers by a predetermined gap, respectively.

2. The gyroscope as set forth in claim 1,

wherein the outer elastic element unit includes first to third outer elastic elements connected to the anchored pads of the anchored pad unit, respectively, for uniformly and elastically supporting the outer frame, and

wherein the first to third outer elastic elements have the same structure.

3. The gyroscope as set forth in claim 1, wherein the driven electrode of the outer frame includes:

driven electrode beams formed at the outside of the outer frame so that each of the driven electrode beams has a predetermined length in the direction perpendicular to the outer frame; and

electrode fingers forming a comb structure arranged along the longitudinal direction of each of the driven electrode beams.

4. The gyroscope as set forth in claim 3, wherein the inner elastic element unit includes:

first and second inner elastic elements inwardly extended from the inner circumference of the outer frame while the first and second inner elastic elements are opposite to each other in the direction of the Y-axis; and

third and fourth inner elastic elements inwardly extended from the inner circumference of the outer frame while the first and second inner elastic elements are opposite to each other in the direction of the X-axis.

5. The gyroscope as set forth in claim 4, wherein each of the third and fourth inner elastic elements includes:

a body part formed on the inner circumference of the outer frame so that the body part of the third inner elastic element is opposite to the body of the fourth inner elastic element in the direction of the X-axis; and

a pair of arm parts extended from the body part so that each of the arm parts has a predetermined length in the direction of the X-axis, the arm parts being connected to the pair of inner weighted elements, respectively.

6. The gyroscope as set forth in claim 5, wherein the pair of arm parts of each of the third and fourth inner elastic elements are formed with the same width.

7. The gyroscope as set forth in claim 5, wherein each of the third and fourth inner elastic elements is formed in the shape of “

π

”

obtained by combination of the body part and the pair of arm parts.

8. The gyroscope as set forth in claim 3,

wherein the first and second inner elastic elements are symmetrical to each other, and

wherein each of the first and second inner elastic elements includes:

an outer connection part connected to the inside of the outer frame in the direction of the Y-axis;

an inner connection part connected to the outside of the inner weighted element unit in the direction of the Y-axis; and

an interconnection part having a predetermined length in the direction of the X-axis for interconnecting the outer connection part and the inner connection part.

9. The gyroscope as set forth in claim 8, wherein the length of the interconnection part is larger than that of the outer connection part or that of the inner connection part.

10. The gyroscope as set forth in claim 1, wherein the driven electrode unit includes:

a driven electrode pad fixed to the substrate;

a driven electrode beam having a predetermined length and extended from the driven electrode pad while the driven electrode beam is spaced apart from the driven electrode beam of the outer frame by a predetermined gap; and

driven electrode fingers forming a comb structure formed at the driven electrode beam and meshing with the driven electrode fingers having the comb structure of the outer frame while the driven electrode fingers are spaced apart from the driven electrode fingers of the outer frame by a predetermined gap, respectively.

11. The gyroscope as set forth in claim 1, wherein the pair of first and second inner weighted elements of the inner weighted element unit are disposed in the outer frame while the inner weighted elements are spaced apart from each other by a predetermined gap in the direction of the Y-axis, each of the first and second inner weighted elements is formed in the shape of a semicircle, and the first and second inner weighted elements are symmetrical to each other about the X-axis.

12. The gyroscope as set forth in claim 11, wherein the first inner weighted element of the inner weighted element unit includes:

a weighted element frame disposed at one side in the outer frame in the direction of the Y-axis and having an inner space defined therein, the weighted element frame comprising a semicircular frame part formed along the inner circumference of the outer frame while the semicircular frame part is spaced apart from the inner circumference of the outer frame by a predetermined gap, and a linear frame part formed in the direction of the X-axis while the linear frame part is spaced apart from the second inner weighted element by a predetermined gap;

weighted element beams formed at the weighted element frame and each having a predetermined length in the inner space of the weighted element frame; and

weighted element fingers forming comb structures arranged in the longitudinal directions of the weighted element beams, respectively, and each having a predetermined length in the direction parallel to the semicircular frame part of the weighted element frame.

13. The gyroscope as set forth in claim 12, wherein the second inner weighted element of the inner weighted element unit includes:

a weighted element frame disposed at the other side in the outer frame in the direction of the Y-axis and having a inner space defined therein, the weighted element frame comprising a semicircular frame part formed along the inner circumference of the outer frame while the semicircular frame part is spaced apart from the inner circumference of the outer frame by a predetermined gap, and a linear frame part formed in the direction of the X-axis while the linear frame part is spaced apart from the linear frame part of the first inner weighted element by a predetermined gap;

weighted element beams formed at the weighted element frame and each having a predetermined length in the inner space of the weighted element frame; and

weighted element fingers forming comb structures arranged in the longitudinal directions of the weighted element beams, respectively, and each having a predetermined length in the direction parallel to the semicircular frame part of the weighted element frame.

14. The gyroscope as set forth in claim 12, wherein the pair of inner weighted elements are formed with substantially the same structure.

15. The gyroscope as set forth in claim 1, wherein the first sensing electrode of the sensing electrode unit includes:

a sensing electrode pad disposed in the inner space of the first inner weighted element and fixed to the substrate;

sensing electrode beams extended from the sensing electrode pad and disposed between the weighted element beams of the first weighted element so that the sensing electrode beams and the weighted element beams are alternately arranged; and

sensing electrode fingers formed at the sensing electrode beam, the sensing electrode fingers being radially arranged and meshing with the weighted element fingers of the first weighted element while the sensing electrode fingers are spaced apart from the weighted element fingers, respectively.

16. The gyroscope as set forth in claim 1, wherein the second sensing electrode of the sensing electrode unit includes:

a sensing electrode pad disposed in the inner space of the second inner weighted element and fixed to the substrate;

sensing electrode beams extended from the sensing electrode pad and disposed between the weighted element beams of the first weighted element so that the sensing electrode beams and the weighted element beams are alternately arranged; and

sensing electrode fingers formed at the sensing electrode beam, the sensing electrode fingers being radially arranged and meshing with the weighted element fingers of the first weighted element while the sensing electrode fingers are spaced apart from the weighted element fingers, respectively.

17. The gyroscope as set forth in claim 1,

wherein the outer frame has feedback electrodes formed at the outside thereof, and

wherein each of the feedback electrodes includes:

a feedback electrode beam radially extended from the outer circumference of the outer frame so that the feedback electrode beam has a predetermined length in the direction substantially perpendicular to the outer frame; and

feedback electrode fingers forming a comb structure arranged in the longitudinal direction of the feedback electrode beam.

18. The gyroscope as set forth in claim 17, further comprising:

a feedback electrode unit for detecting a capacitance on the basis of the gap between the feedback electrode unit and the feedback electrode fingers of the outer frame.

19. The gyroscope as set forth in claim 18, wherein the feedback electrode unit includes:

a feedback electrode pad fixed to the substrate;

a feedback electrode beam extended from the feedback electrode pad while the feedback electrode beam is spaced apart from the feedback electrode beams of the outer frame, the feedback electrode beam having a predetermined length; and

feedback electrode fingers forming a comb structure extended from the feedback electrode beam, the feedback electrode fingers meshing with the feedback electrode fingers of the outer frame while the feedback electrode fingers are spaced apart from the feedback electrode fingers by a predetermined gap, respectively.