Vibration type gyroscope and method for manufacturing vibration type gyroscope
AssigneeSeiko Epson Corporation
InventorsOsamu Kawauchi, Shigeki Miyazawa, Katsumi Takayama, Keiichi Yamaguchi
Life of this patent
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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.
Claims15
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, extending in a first plane, and including a first pair of drive arms and a second pair of drive arms;
- a detection section for detecting a detection vibration caused by a Coriolis force involved in rotation of the drive section, the detection section extending from the base into the first plane and including a pair of detection arms disposed between the first pair of drive arms and the second pair of drive arms;
- 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.
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 including a first pair of drive arms and a second pair of drive arms;
- and a detection section for detecting a detection vibration caused by a Coriolis force involved in rotation of the drive section and including a pair of detection arms disposed between the first pair of drive arms and the second pair of drive arms, the method comprising:
- forming an electrode film in a 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 an 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.
Dependencies are inferred from the claim text.