Horizontal and tuning fork vibratory microgyroscope

• US 7,004,024 B1
• Filed: 07/02/2003
• Issued: 02/28/2006
• Est. Priority Date: 12/24/2002
• Status: Expired due to Fees

• 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, John E.
• Application Number:
  US10/610,624
• Publication Number:
  US 20060053885A1
• Time in Patent Office: 972 Days
• Field of Search: 735/041.6, 735/041.2, 735/041.4, 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 is provided for detecting 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 square 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 having vibrating electrode fingers forming a comb structure;

a sensing electrode unit including a plurality of sensing electrodes forming a comb structure, the sensing electrodes meshing with the vibrating electrode fingers of the outer frame while the sensing electrodes are spaced apart from the vibrating electrode fingers by a predetermined gap, respectively;

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, 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 driven electrode unit including first and second driven electrodes each having a comb drive forming a comb structure, the first and second driven electrodes meshing with the first and second inner weighted elements of the inner weighted element unit while the first and second driven electrodes are spaced apart from the first and second inner weighted elements by a predetermined gap, respectively.

2. The gyroscope as set forth in claim 1,

wherein the outer elastic element unit includes first to fourth outer elastic elements, each of the first to fourth outer elastic elements being connected to the outer center of each side of the outer frame, and

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

3. The gyroscope as set forth in claim 1,

wherein the outer frame includes two sides spaced apart from each other in the direction of a X-axis, and two other sides spaced apart from each other in the direction of a Y-axis, the sides substantially forming a square, and

wherein the vibrating electrode fingers of the outer frame are formed at outer parts of the two sides in the direction of the X-axis, respectively, so that the vibrating electrode fingers of the outer frame are arranged in the form of a comb structure in the direction of the Y-axis, respectively.

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

a sensing electrode pad fixed to the substrate;

a sensing electrode beam extended from the sensing electrode pad in the direction of the X-axis; and

a plurality of sensing electrode fingers forming a comb structure, the sensing electrode fingers being formed at the sensing electrode beam and arranged in the direction of the X-axis, the sensing electrode fingers meshing with the vibrating electrode fingers having the comb structure of the outer frame while the sensing electrode fingers are spaced apart from the vibrating electrode fingers by a predetermined gap, respectively,

thereby detecting a capacitance based on the gap between the sensing electrode fingers and the vibrating electrode fingers of the outer frame.

5. The gyroscope as set forth in claim 3, wherein the plurality of inner elastic elements of the inner elastic element unit include:

first to fourth inner elastic elements each inwardly extended from both ends of each of the two sides disposed in the direction of the Y-axis among the four sides of the outer frame; and

fifth and sixth inner elastic elements each inwardly extended from the center of each of the two sides disposed in the direction of the Y-axis among the four sides of the outer frame.

6. The gyroscope as set forth in claim 5, wherein each of the first to fourth inner elastic elements includes:

an outer connection part connected in the direction of the X-axis to the inside of the two sides of the outer frame arranged 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;

an extension part extended from the end of the inner connection part in the direction of the X-axis; and

a bent connection part for connecting the outer connection part and the extension part.

7. The gyroscope as set forth in claim 6, wherein the length of the outer connection part of each of the first to fourth inner elastic elements is larger than the length of the extension part of each of the first to fourth inner elastic elements, and

wherein the length of the extension part of each of the first to fourth inner elastic elements is larger than the length of the inner connection part of each of the first to fourth inner elastic elements.

8. The gyroscope as set forth in claim 5, wherein each of the fifth and sixth inner elastic elements includes:

a body part formed at the inside center of each of the two sides of the outer frame arranged in the direction of the Y-axis; and

a pair of arm parts each having one end connected to the body part and the other end connected to each of the pair of inner weighted elements.

9. The gyroscope as set forth in claim 8, wherein each of the arm parts includes:

an outer connection part connected to the body part so that the outer connection part has a predetermined length in the direction of the X-axis;

an inner connection part connected to the outside of the inner weighted element unit so that the inner connection part has a predetermined length in the direction of the X-axis;

an extension part extended from the end of the inner connection part in the direction of the X-axis; and

a bent connection part for connecting the outer connection part and the extension part.

10. The gyroscope as set forth in claim 9,

wherein the length of the outer connection part of each of the arm parts is larger than the length of the extension part of each of the arm parts, and

wherein the length of the extension part of each of the arm parts is larger than the length of the inner connection part of each of the arm parts.

11. The gyroscope as set forth in claim 8, wherein the pair of arm parts of each of the fifth and sixth inner elastic elements are formed with the same width.

12. The gyroscope as set forth in claim 8, wherein each of the fifth and sixth inner elastic elements is formed in the shape of “

π

”

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

13. The gyroscope as set forth in claim 5, wherein the first inner weighted element includes:

two weighted element frames spaced apart from each other in the direction of the Y-axis, each of the weighted element frames having one end connected to one of the arm parts of each of the fifth and sixth inner elastic elements of the inner elastic element unit, and the other end connected to each of the first and second inner elastic elements;

frame driving beams disposed between the weighted element frames and extended in the direction of the X-axis;

driven combs repetitively arranged in the direction of the X-axis along the frame driving beams, respectively;

a frame sensing beam connected between the weighted element frames in the direction of the X-axis and spaced apart from the frame driving beams by a predetermined gap; and

a feedback comb formed at the frame sensing beam and repetitively arranged in the direction of the X-axis.

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

two weighted element frames spaced apart from each other in the direction of the Y-axis, each of the weighted element frames having one end connected to the other of the arm parts of each of the fifth and sixth inner elastic elements of the inner elastic element unit, and the other end connected to each of the third and fourth inner elastic elements;

frame driving beams disposed between the weighted element frames and extended in the direction of the X-axis;

driven combs repetitively arranged in the direction of the X-axis along the frame driving beams, respectively;

a frame sensing beam connected between the weighted element frames in the direction of the X-axis and spaced apart from the frame driving beams by a predetermined gap; and

a feedback comb formed at the frame sensing beam and repetitively arranged in the direction of the X-axis.

15. The gyroscope as set forth in claim 13, wherein the pair of inner weighted elements are formed with substantially the same structure.

16. The gyroscope as set forth in claim 13, wherein the first driven electrode of the driven electrode unit includes:

a driven electrode pad fixed to the substrate and disposed between the weighted element frames of the first weighted element;

driven electrode beams extended from the driven electrode pad so that each of the driven electrode beams has a predetermined length in the direction of the X-axis while the driven electrode beams are spaced apart from the frame driving beams by a predetermined gap, respectively; and

comb drives of comb structures repetitively arranged along the longitudinal directions of the driven electrode beams, respectively.

17. The gyroscope as set forth in claim 13, wherein the second driven electrode of the driven electrode unit includes:

a driven electrode pad fixed to the substrate and disposed between the weighted element frames of the second weighted element;

driven electrode beams extended from the driven electrode pad so that each of the driven electrode beams has a predetermined length in the direction of the X-axis while the driven electrode beams are spaced apart from the frame driving beams by a predetermined gap, respectively; and

comb drives forming comb structures repetitively arranged along the longitudinal directions of the driven electrode beams, respectively.

18. The gyroscope as set forth in claim 1, further comprising:

a feedback electrode unit disposed between the pair of inner weighted elements for detecting a capacitance on the basis of the gap between the feedback electrode unit and the feedback combs of the inner weighted elements.

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

a feedback electrode pad fixed to the substrate;

feedback electrode beams extended from both ends of the feedback electrode pad in the direction of the X-axis, both ends of the feed back electrode pad being formed in the direction of the Y-axis, respectively; and

comb sensors forming comb structures formed at the feedback electrode beams and arranged in the direction of the X-axis, respectively, the comb sensors meshing with the feedback combs of the pair of inner weighted elements while the comb sensors are spaced apart from the feedback combs by a predetermined gap, respectively.