Vibration type gyroscope and method for manufacturing vibration type gyroscope

• US 20060070442A1
• Filed: 09/29/2005
• Published: 04/06/2006
• Est. Priority Date: 09/30/2004
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Yamaguchi, Keiichi, Takayama, Katsumi, Miyazawa, Shigeki, Kawauchi, Osamu
• Granted Patent: US 7,207,221 B2
• Time in Patent Office: Days
• US Class Current: 73/504.120
• CPC Class Codes: G01C 19/5628 Manufacturing; Trimming; Mounting; Housings
• CPC Class Codes: Y10T 29/42 Piezoelectric device making

Abstract

A piezo-electric vibration reed 1 including connection arms extended in opposing directions from a base 12, drive arms extended in a direction perpendicular to the connection arms at the respective tips of the connection arms 13 and 14, and detection arms extended from the base 12 in a direction perpendicular to the connection arms. In the respective tips of the drive arms, and the detection arms, there are formed a first deadweight portion and a second deadweight portion, which are adjustment portions used for mass adjustment. The adjustment portions are formed of deadweight layers and an electrode film.

Claims

1. A vibration-type gyroscope that detects a rotation angular velocity to be applied to a piezo-electric vibration reed, the piezo-electric vibration reed comprising:

a base;

a drive section for carrying out a predetermined vibration, the drive section being provided through a supporting beam extended from the base;

a detection section for detecting a detection vibration caused by a Coriolis force involved in rotation of the drive section, the detection section being extended from the base into a same plane as that of the drive section;

a first deadweight portion used for characteristic adjustment of the piezo-electric vibration reed, the first deadweight portion being formed in a tip portion of the drive section; and

a second deadweight portion used for characteristic adjustment of the piezo-electric vibration reed, the second deadweight portion being formed in a tip portion of the detection section;

wherein at least one of the first deadweight portion and the second deadweight portion is formed of a plurality of adjustment portions having different mass per unit area.

2. The vibration-type gyroscope according to claim 1, wherein a mass of the first deadweight portion is set to be smaller than a mass of the second deadweight portion.

3. The vibration-type gyroscope according to claim 1, wherein in the drive section the adjustment portion is formed over an entire region in a direction roughly perpendicular to the extending direction of the drive section, and in the detection section the adjustment portion is formed over an entire region in a direction roughly perpendicular to the extending direction of the detection section.

4. The vibration-type gyroscope according to claim 1, wherein at least one of the first deadweight portion and the second deadweight portion is formed of a plurality of adjustment portions with different thicknesses.

5. The vibration-type gyroscope according to claim 4, wherein the adjustment portion in the first deadweight portion and the adjustment portion in the second deadweight portion are formed to have a same thickness using a same metal.

6. The vibration-type gyroscope according to claim 4, wherein in the plurality of adjustment portions with different thickness, a thickness of the adjustment portion at a side near the tip of the drive section or the detection section is formed thicker than a thickness of the other adjustment portions.

7. A vibration-type gyroscope comprising:

a retainer; and

the piezo-electric vibration reed according to claim 1, the piezo-electric vibration reed being mounted in the retainer.

8. A vibration-type gyroscope comprising:

a retainer;

the piezo-electric vibration reed according to claim1, the piezo-electric vibration reed being mounted in the retainer; and

a circuit element having a circuit for driving at least the piezo-electric vibration reed, the circuit element being mounted in the retainer.

9. A method for manufacturing a vibration-type gyroscope provided with a piezo-electric vibration reed, the piezo-electric vibration reed having a drive section for carrying out a predetermined vibration;

and a detection section for detecting a detection vibration caused by a Coriolis force involved in rotation of the drive section the method comprising;

forming an electrode film in the surface of the piezo-electric vibration reed whose outline shape has been formed;

forming a deadweight layer as an adjustment portion in a surface of the electrode film formed in a tip portion of the detection section as well as in a part of the surface of the electrode film formed in a tip portion of the drive section;

adjusting an intrinsic resonance frequency of the detection section by removing at least the deadweight layer formed in the tip portion of the detection section;

carrying out a coarse adjustment of the intrinsic resonance frequency of the drive section by removing the deadweight layer formed in the tip portion of the drive section; and

carrying out a fine adjustment of the intrinsic resonance frequency of the drive section by removing the electrode film in the tip portion of the drive section.