Vibrators and vibratory gyroscopes

• US 6,698,292 B2
• Filed: 03/10/2003
• Issued: 03/02/2004
• Est. Priority Date: 03/13/2002
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: NGK Insulators Limited
• Inventors: Kikuchi, Takayuki
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): SAINT SURIN, JACQUES M
• Application Number:
  US10/384,958
• Publication Number:
  US 20030177836A1
• Time in Patent Office: 358 Days
• Field of Search: 736/62, 735/033, 735/041.2, 73/17.7, 735/041.1, 735/040.2, 735/040.4, 735/041.6, 310/311
• US Class Current: 73/662
• CPC Class Codes: G01C 19/5607 using vibrating tuning forks double-ended tuning forks using planar vibrating masses suspended at opposite ends G01C19/5719

Abstract

An object of the present invention is to reduce the zero point temperature drift of a vibrator and the deviation or change of the drift among vibrators actually fabricated. A vibrator has a driving vibration piece 2A, a detection vibration piece and a base portion connecting the driving and detection vibration pieces. The driving vibration piece 2A is composed of a bending vibration piece having a pair of surfaces 2c and 2d parallel with each other and a pair of side faces 2a and 2b. The driving vibration piece 2A has a ratio (WD/TD) of a width WD to a thickness TD of not smaller than 1.5 and not larger than 2.4.

Claims

1. A vibrator comprising a driving vibration piece, a detection vibration piece and a base portion connecting said driving vibration piece and detection vibration piece,

wherein said driving vibration piece is composed of a bending vibration piece comprising a pair of surfaces parallel with each other and a pair of side faces, and said driving vibration piece has a ratio (WD/TD) of a width WD to a thickness TD of not smaller than 1.5 and not larger than 2.4.

2. The vibrator of claim 1, wherein said driving vibration piece and said detection vibration piece vibrate in bending vibration mode along a specified plane, respectively.

3. The vibrator of claim 2, wherein said specified plane is substantially parallel with said surface.

4. The vibrator of claim 1, further comprising a supporting part protruding from said base portion, wherein said driving vibration piece is supported with said supporting part.

5. The vibrator of claim 1, wherein a detecting means is not provided on said driving vibration piece.

6. The vibrator of claim 1, wherein said detection vibration piece is a bending vibration piece comprising a pair of surfaces substantially parallel with each other and a pair of side faces and has a ratio (WT/TT) of a width WT to a thickness TT of not smaller than 1.5 and not larger than 3.0.

7. The vibrator of claim 1, wherein said detection vibration piece is a bending vibration piece comprising a pair of surfaces substantially parallel with each other and a pair of side faces and has a ratio (WT/TT) of a width WT to a thickness TT of not smaller than 0.3 and not larger than 0.8.

8. The vibrator of claim 1 composed of a piezoelectric single crystal.

9. The vibrator of claim 8, wherein said piezoelectric single crystal is quartz.

10. The vibrator of claim 1 formed by etching.

11. The vibrator of claim 1, wherein one of said side faces is [2{overscore (11)}0] face and the other of said side faces is [{overscore (2)}110] face.

12. A vibratory gyroscope comprising the vibrator of claim 1.

13. The gyroscope of claim 12 for detecting a turning angular rate around an axis perpendicular to said surface.

14. A vibrator comprising a driving vibration piece, a detection vibration piece and a base portion connecting said driving vibration piece and detection vibration piece,

wherein said driving vibration piece is composed of a bending vibration piece comprising a pair of surfaces substantially parallel with each other and a pair of side faces, and said driving vibration piece has a ratio (WD/TD) of a width WD to a thickness TD of not smaller than 0.3 and not larger than 0.8.

15. The vibrator of claim 14, wherein said driving vibration piece and said detection vibration piece vibrate in bending vibration mode along a specified plane, respectively.

16. The vibrator of claim 15, wherein said specified plane is substantially parallel with said surface.

17. The vibrator of claim 14, further comprising a supporting part protruding from said base portion, wherein said driving vibration piece is supported with said supporting part.

18. The vibrator of claim 14, wherein a detecting means is not provided on said driving vibration piece.

19. The vibrator of claim 14, wherein said detection vibration piece is a bending vibration piece comprising a pair of surfaces substantially parallel with each other and a pair of side faces and has a ratio (WT/TT) of a width WT to a thickness TT of not smaller than 1.5 and not larger than 3.0.

20. The vibrator of claim 14, wherein said detection vibration piece is a bending vibration piece comprising a pair of surfaces substantially parallel with each other and a pair of side faces and has a ratio (WT/TT) of a width WT to a thickness TT of not smaller than 0.3 and not larger than 0.8.

21. The vibrator of claim 14 composed of a piezoelectric single crystal.

22. The vibrator of claim 21, wherein said piezoelectric single crystal is quartz.

23. The vibrator of claim 14 formed by etching.

24. The vibrator of claim 14, wherein one of said side faces is [2{overscore (11)}0] face and the other of said side faces is [{overscore (2)}110] face.

25. A vibratory gyroscope comprising the vibrator of claim 14.

26. The gyroscope of claim 25 for detecting a turning angular rate around an axis perpendicular to said surface.