JP4552253B2

JP4552253B2 - Angular velocity sensor

Info

Publication number: JP4552253B2
Application number: JP2000050604A
Authority: JP
Inventors: 二郎寺田; 克憲松原; 毅山本; 俊彦市瀬; 潤一湯河; 雅己田村; 正数畑中; 茂裕 ▲吉▼内; 澄夫菅原
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2000-02-28
Filing date: 2000-02-28
Publication date: 2010-09-29
Anticipated expiration: 2020-02-28
Also published as: JP2001241952A

Description

【０００１】
【発明の属する技術分野】
本発明は例えば自動車の姿勢制御、ナビゲーション、カメラの手振れ防止、遠隔操作用のリモコンなどに用いられる角速度センサに関するものである。
【０００２】
【従来の技術】
従来の薄型の角速度センサとしては、特開平１０−１７０２７６号公報に記載されたものが知られている。この角速度センサは、中央部にある付加質量部が細い梁により平面内で支持された構造である。また、この付加質量部を平面内で駆動するための駆動部と、平面と直交する軸周りに角速度が印加された時、付加質量部に働くコリオリ力により、付加質量部が変位する変位量を検出するための検出部とがともに櫛歯構造の電極より構成されている。
【０００３】
【発明が解決しようとする課題】
このような角速度センサは、比較的薄型な構造を実現できるものの、駆動するために櫛歯構造の電極同士を対向させ、これらの電極同士に働く吸引力により駆動しなければならない。したがって、これらの電極同士を極めて微小な間隙で且つ高精度に形成しなければならない。
【０００４】
また、微弱な信号を高精度に検出できるようにするためには、対向する櫛歯構造の電極同士を極めて微小な間隙で且つ高精度に形成しなければならないばかりか対向する櫛歯を多数設けなければならないといった課題を有していた。
【０００５】
本発明はこの課題を解決するものであり、駆動及び検出のための高精度な櫛歯構造の電極を形成することなく薄型且つ高感度な角速度センサを提供することを目的とする。
【０００６】
【課題を解決するための手段】
ＸＹ面内に設けられた基部と、ＸＹ面内において前記基部からＹ軸方向と反対の方向に延出した少なくとも一対の音叉片からなる第１の音叉部と、前記第１の音叉部に相対向するように前記基部からＹ軸方向に延出した少なくとも一対の音叉片からなる第２の音叉部と、前記第１の音叉部を構成する対をなした音叉片の間にあり且つ前記基部からＹ軸方向と反対の方向に延出した少なくとも１本以上の屈曲振動片からなる第１の屈曲振動部と、前記第２の音叉部を構成する対をなした音叉片の間にあり且つ前記第１の屈曲振動部に相対向するように前記基部からＹ軸方向に延出した少なくとも１本以上の屈曲振動片からなる第２の屈曲振動部と、前記第１、第２の音叉部を構成する音叉片をＸ軸方向またはＸ軸方向と反対の方向へ屈曲振動させるために前記音叉片に設けられた駆動手段と、Ｚ軸周りの角速度が印加された時、Ｙ軸方向またはＹ軸方向と反対の方向に働くコリオリ力の大きさに応じて変化する前記音叉片の屈曲変形と釣り合いを保つようにＸ軸方向またはＸ軸方向と反対の方向に屈曲変形する前記屈曲振動片の変形量を検出するために前記屈曲振動片に設けられた検出手段とを備えたことを特徴とするものである。この構成により、駆動及び検出のための高精度な櫛歯構造の電極を形成することなく薄型且つ高感度な角速度センサが得られる。
【０００７】
【発明の実施の形態】
本発明の請求項１に記載の発明は、ＸＹ面内に設けられた基部と、ＸＹ面内において前記基部からＹ軸方向と反対の方向に延出した少なくとも一対の音叉片からなる第１の音叉部と、前記第１の音叉部に相対向するように前記基部からＹ軸方向に延出した少なくとも一対の音叉片からなる第２の音叉部と、前記第１の音叉部を構成する対をなした音叉片の間にあり且つ前記基部からＹ軸方向と反対の方向に延出した少なくとも１本以上の屈曲振動片からなる第１の屈曲振動部と、前記第２の音叉部を構成する対をなした音叉片の間にあり且つ前記第１の屈曲振動部に相対向するように前記基部からＹ軸方向に延出した少なくとも１本以上の屈曲振動片からなる第２の屈曲振動部と、前記第１、第２の音叉部を構成する音叉片をＸ軸方向またはＸ軸方向と反対の方向へ屈曲振動させるために前記音叉片に設けられた駆動手段と、Ｚ軸周りの角速度が印加された時、Ｙ軸方向またはＹ軸方向と反対の方向に働くコリオリ力の大きさに応じて変化する前記音叉片の屈曲変形と釣り合いを保つようにＸ軸方向またはＸ軸方向と反対の方向に屈曲変形する前記屈曲振動片の変形量を検出するために前記屈曲振動片に設けられた検出手段とを備えているため、駆動及び検出のための高精度な櫛歯構造の電極を形成することなく薄型化且つ高感度化が図れるという作用を有する。
【０００８】
請求項２に記載の発明は、請求項１に記載の発明において、第１、第２の音叉部を構成する対をなした音叉片の各先端からＸ軸方向またはＸ軸方向と反対の方向の内のいずれか一方の方向であり、前記第１、第２の音叉部の各対称軸を中心にして両側にある前記音叉片同士にあっては互いに逆向きで且つ同じ側にあっては同一向きに延出するように第１の付加質量部が形成され、第１、第２の屈曲振動部を構成する各々１本の屈曲振動片は前記音叉部の対称軸上にあり、前記各屈曲振動片の先端からＸ軸方向及びＸ軸方向と反対の方向に張り出すように第２の付加質量部が形成された構成であるため、小さな角速度入力に対しても音叉部の変形量が大きくなり、これに呼応するように屈曲振動部の変形量も大きくなり、検出信号のさらなる高感度化が図れると同時に付加質量部の調整により音叉部と屈曲振動部の各共振周波数の調整が容易になるという作用を有する。
【０００９】
請求項３に記載の発明は、請求項１または２に記載の発明において、第１、第２の音叉部の共振周波数と第１、第２の屈曲振動部の共振周波数を近接させた構成としているため、検出信号のより高感度化が図れるという作用を有する。
【００１０】
請求項４に記載の発明は、請求項１または２に記載の発明において、第１、第２の屈曲振動部に設けられた検出手段により検出された各検出信号を差動検出処理するための処理回路が前記検出手段に接続された構成であるため、Ｘ軸方向、Ｙ軸方向、Ｚ軸方向の３軸方向から加わる加速度成分に基づく外乱信号を除去できるという作用を有する。
【００１１】
請求項５に記載の発明は、請求項１に記載の発明において、ＸＹ面内に設けられた基部、第１、第２の音叉部と第１、第２の屈曲振動部は、圧電材料により一体に形成された構成としているため、圧電特性の均一な平板から極めて容易に一体構造を形成可能といった作用を有する。
【００１２】
請求項６に記載の発明は、請求項２に記載の発明において、ＸＹ面内に設けられた基部、第１、第２の音叉部、第１、第２の屈曲振動部と第１、第２の付加質量部は、圧電材料により一体に形成された構成としているため、圧電特性の均一な平板から極めて容易に一体構造を形成可能といった作用を有する。
【００１３】
請求項７に記載の発明は、請求項１に記載の発明において、ＸＹ面内に設けられた基部、第１、第２の音叉部と第１、第２の屈曲振動部は、恒弾性金属材料、酸化物材料または高弾性高分子材料により形成され、少なくとも前記第１、第２の音叉部と前記第１、第２の屈曲振動部のＸＹ面上には圧電材料からなる層が設けられた構成であるため、機械的振動特性としての高いＱを有する材料と圧電定数の大きな圧電材料を自由に組合わせることが可能となるといった作用を有する。
【００１４】
請求項８に記載の発明は、請求項２に記載の発明において、ＸＹ面内に設けられた基部、第１、第２の音叉部、第１、第２の屈曲振動部と第１、第２の付加質量部は、恒弾性金属材料、酸化物材料または高弾性高分子材料により形成され、少なくとも前記第１、第２の音叉部と前記第１、第２の屈曲振動部のＸＹ面上には圧電材料からなる層が設けられた構成であるため、機械的振動特性としての高いＱを有する材料と圧電定数の大きな圧電材料を自由に組合わせることが可能となるといった作用を有する。
【００１５】
また、ＸＹ面内に設けられた基部と、ＸＹ面内において前記基部からＹ軸方向と反対の方向に延出した振動片と、前記振動片の先端からＸ軸方向またはＸ軸方向と反対の方向の内の少なくともいずれか一方の方向に延出するように形成された付加質量部と、前記振動片をＸ軸方向またはＸ軸方向と反対の方向へ屈曲振動させるために前記振動片に設けられた駆動手段と、Ｚ軸周りの角速度が印加された時、Ｙ軸方向またはＹ軸方向と反対の方向に働くコリオリ力の大きさに応じて変化する前記振動片のＸ軸方向またはＸ軸方向と反対の方向への屈曲振動の振幅の増減量を検出するために前記振動片に設けられた前記駆動手段と兼用した検出手段とを備えているため、駆動及び検出のための高精度な櫛歯構造の電極を形成することなく薄型化且つ高感度化が図れるばかりか、振動片を駆動させる駆動電圧に角速度の印加に起因した検出信号が重畳する状態で検出可能になるという作用を有する。
【００１６】
また上記構成において、ＸＹ面内に設けられた基部、振動片と付加質量部は、圧電材料により一体に形成された構成としているため、圧電特性の均一な平板から極めて容易に一体構造を形成可能といった作用を有する。
【００１７】
また上記構成において、ＸＹ面内に設けられた基部、振動片と付加質量部は、恒弾性金属材料、酸化物材料または高弾性高分子材料により形成され、少なくとも前記振動片のＸＹ面上には圧電材料からなる層が設けられた構成であるため、機械的振動特性としての高いＱを有する材料と圧電定数の大きな圧電材料を自由に組合わせることが可能となるといった作用を有する。
【００１８】
また、Ｙ軸方向に伸びた振動片と、前記振動片の両端からそれぞれＸ軸方向若しくはＸ軸方向と反対の方向の内のいずれか一方の方向または両方向に延出した付加質量部と、前記振動片をＹ軸上で対称に支持するために前記振動片の一方のＸＹ面に設けられた第１、第２の支持点と、前記振動片の他方のＸＹ面に設けられた第３、第４の支持点と、前記第１、第３の支持点から同一直線上にあるようにＺ軸方向及びＺ軸方向と反対の方向にそれぞれ延出した第１、第３の支持部と、前記第２、第４の支持点から同一直線上にあるようにＺ軸方向及びＺ軸方向と反対の方向にそれぞれ延出した第２、第４の支持部と、前記振動片を前記第１、第２、第３、第４の支持点を振動の節にしてＸＹ面内で１次モードで屈曲振動させるために前記振動片に設けられた駆動手段と、Ｚ軸周りの角速度が印加された時、Ｙ軸方向またはＹ軸方向と反対の方向に働くコリオリ力の大きさに応じて変化する前記振動片のＸ軸方向またはＸ軸方向と反対の方向の屈曲振動の振幅の増減量を検出するために前記振動片に設けられた前記駆動手段と兼用した検出手段とを備えているため、駆動及び検出のための高精度な櫛歯構造の電極を形成することなく薄型化且つ高感度化が図れるばかりか、振動片を駆動させる駆動電圧に角速度の印加に起因した検出信号が重畳する状態で検出可能になるという作用を有する。
【００１９】
また上記構成において、振動片と付加質量部は、圧電材料により一体に形成された構成としているため、圧電特性の均一な平板から極めて容易に一体構造を形成可能といった作用を有する。
【００２０】
また上記構成において、振動片と付加質量部は、恒弾性金属材料、酸化物材料または高弾性高分子材料により形成され、少なくとも前記振動片のＸＹ面上には圧電材料からなる層が設けられた構成であるため、機械的振動特性としての高いＱを有する材料と圧電定数の大きな圧電材料を自由に組合わせることが可能となるといった作用を有する。
【００２１】
また、ＸＹ面内に設けられた基部と、ＸＹ面内において前記基部から延出した一対の音叉片と、前記一対の音叉片の各先端からＸ軸方向またはＸ軸方向と反対の方向の内のいずれか一方の方向に延出するように形成された付加質量部と、前記一対の音叉片をＸ軸方向またはＸ軸方向と反対の方向へ屈曲振動させるために前記一対の音叉片に設けられた駆動手段と、Ｚ軸周りの角速度が印加された時、Ｙ軸方向またはＹ軸方向と反対の方向に働くコリオリ力の大きさに応じて変化する前記一対の音叉片のＸ軸方向またはＸ軸方向と反対の方向への屈曲振動の振幅の増減量を検出するために前記一対の音叉片に設けられた前記駆動手段と兼用した検出手段とを備えているため、駆動及び検出のための高精度な櫛歯構造の電極を形成することなく薄型化且つ高感度化が図れるばかりか、振動片を駆動させる駆動電圧に角速度の印加に起因した検出信号が重畳する状態で検出可能になるという作用を有する。
【００２２】
また上記構成において、ＸＹ面内に設けられた基部、一対の音叉片と付加質量部は、圧電材料により一体に形成された構成としているため、圧電特性の均一な平板から極めて容易に一体構造を形成可能といった作用を有する。
【００２３】
また上記構成において、ＸＹ面内に設けられた基部、一対の音叉片と付加質量部は、恒弾性金属材料、酸化物材料または高弾性高分子材料により形成され、少なくとも前記一対の音叉片のＸＹ面上には圧電材料からなる層が設けられた構成であるため、機械的振動特性としての高いＱを有する材料と圧電定数の大きな圧電材料を自由に組合わせることが可能となるといった作用を有する。
【００２４】
また、ＸＹ面内に設けられた基部と、ＸＹ面内において前記基部からＹ軸方向に延出した少なくとも一対の音叉片と、前記対をなす音叉片の対称軸を中心にしてＸ軸方向側にある前記音叉片及びＸ軸方向と反対の方向の側にある前記音叉片ともに各先端からＸ軸方向またはＸ軸方向と反対の方向の内のいずれか一方の方向であり且つ同じ側にあっては同一方向に延出するように形成された付加質量部と、前記対をなす音叉片の間にあり且つ前記基部からＹ軸方向に延出した少なくとも１本以上の屈曲振動片と、前記音叉片をＸ軸方向またはＸ軸方向と反対の方向へ屈曲振動させるために前記音叉片に設けられた駆動手段と、Ｚ軸周りの角速度が印加された時、Ｙ軸方向またはＹ軸方向と反対の方向に働くコリオリ力の大きさに応じて変化する前記音叉片の屈曲変形と釣り合いを保つようにＸ軸方向またはＸ軸方向と反対の方向に屈曲変形する前記屈曲振動片の変形量を検出するために前記屈曲振動片に設けられた検出手段とを備えているため、駆動及び検出のための高精度な櫛歯構造の電極を形成することなく薄型化且つ高感度化が図れるという作用を有する。
【００２５】
また上記構成において、ＸＹ面内に設けられた基部、音叉片、付加質量部と屈曲振動片は、圧電材料により一体に形成された構成としているため、圧電特性の均一な平板から極めて容易に一体構造を形成可能といった作用を有する。
【００２６】
また上記構成において、ＸＹ面内に設けられた基部、音叉片、付加質量部と屈曲振動片は、恒弾性金属材料、酸化物材料または高弾性高分子材料により形成され、少なくとも前記音叉片と屈曲振動片のＸＹ面上には圧電材料からなる層を設けられた構成であるため、機械的振動特性としての高いＱを有する材料と圧電定数の大きな圧電材料を自由に組合わせることが可能となるといった作用を有する。
【００２７】
また、ＸＹ面内に設けられた２個所の基部と、ＸＹ面内において前記各基部同士をＹ軸方向で接続するように形成された第１の支持部と、前記第１の支持部の中央部からＸ軸方向及びＸ軸方向と反対の方向に延出した第２、第３の支持部と、前記第２の支持部の先端からＹ軸方向及びＹ軸方向と反対の方向に延出した第１、第２の振動片と、前記第３の支持部の先端からＹ軸方向及びＹ軸方向と反対の方向に延出した第３、第４の振動片と、前記第１、第２、第３、第４の振動片の各先端からＸ軸方向またはＸ軸方向と反対の方向の内のいずれか一方の方向に延出するように形成された付加質量部と、正極性または負極性の駆動信号で前記第１、第２の振動片をＸ軸方向またはＸ軸方向と反対の方向に振動させ且つ前記第３、第４の振動片を前記第１、第２の振動片と逆の方向に同時に振動させるために前記第１、第２、第３、第４の振動片に設けられた駆動手段と、Ｚ軸周りの角速度が印加された時、Ｙ軸方向またはＹ軸方向と反対の方向に働くコリオリ力の大きさに応じて変化する前記第１、第２、第３、第４の振動片のＸ軸方向またはＸ軸方向と反対の方向への屈曲振動の振幅の増減量を検出するために前記第１、第２、第３、第４の振動片に設けられた前記駆動手段と兼用した検出手段とを備えているため、駆動及び検出のための高精度な櫛歯構造の電極を形成することなく薄型化且つより高感度化が図れるばかりか、振動片を駆動させる駆動電圧に角速度の印加に起因した検出信号が重畳する状態で検出可能になるという作用を有する。
【００２８】
また上記構成において、ＸＹ面内に設けられた基部、第１、第２、第３の支持部、第１、第２、第３、第４の振動片と付加質量部は、圧電材料により一体に形成された構成としているため、圧電特性の均一な平板から極めて容易に一体構造を形成可能といった作用を有する。
【００２９】
また上記構成において、ＸＹ面内に設けられた基部、第１、第２、第３の支持部、第１、第２、第３、第４の振動片と付加質量部は、恒弾性金属材料、酸化物材料または高弾性高分子材料により形成され、少なくとも前記第１、第２、第３、第４の振動片のＸＹ面上には圧電材料からなる層が設けられた構成であるため、機械的振動特性としての高いＱを有する材料と圧電定数の大きな圧電材料を自由に組合わせることが可能となるといった作用を有する。
【００３０】
以下、本発明の実施の形態について、図１から図１４を用いて説明する。
【００３１】
（実施の形態１）
図１は、本発明の角速度センサの第１の実施の形態を説明するための平面図である。図１において、駆動方向をＸ軸方向、コリオリ力が発生する方向をＹ軸、角速度Ωの入力軸をＺ軸とする。図１において、１は厚さ（Ｚ軸方向）０．２ｍｍ、長さ（Ｙ軸方向）２０ｍｍ、幅（Ｘ軸方向）１３．３ｍｍの圧電体としての水晶板から構成された基部である。
【００３２】
基部１からＹ軸と反対の方向に第１、第２の音叉片２ａ，２ｂが延出し第１の音叉部が構成され、第１、第２の音叉片２ａ，２ｂとそれぞれ相対向するように基部１からＹ軸方向に第３、第４の音叉片３ａ，３ｂが延出し第２の音叉部が構成されている。第１、第２の音叉片２ａ，２ｂの先端からはＸ軸方向、Ｘ軸方向と反対方向にそれぞれ対称となるように第１、第２の付加質量４ａ，４ｂが延出している。同じく第３、第４の音叉片３ａ，３ｂの先端からは、Ｘ軸方向、Ｘ軸方向と反対方向にそれぞれ対称となるように第３、第４の付加質量５ａ，５ｂが延出しており、第１、第２、第３、第４の付加質量４ａ，４ｂ，５ａ，５ｂにより第１の付加質量部が構成されている。
【００３３】
基部１から第１の音叉部の対称軸上に（すなわち、第１、第２の音叉片２ａ，２ｂの間を通り）Ｙ軸方向と反対の方向に第１の屈曲振動片６が延出し第１の屈曲振動部が構成される。同じく基部１から第２の音叉部の対称軸上に（すなわち、第３、第４の音叉片３ａ，３ｂの間を通り）Ｙ軸方向に第２の屈曲振動片７が延出し第２の屈曲振動部が構成される。第１、第２の屈曲振動片６，７の各先端からＸ軸方向及びＸ軸方向と反対方向に張り出すように第５、第６の付加質量８，９が設けられ、第２の付加質量部が構成されている。基部１、第１、第２、第３、第４の音叉片２ａ，２ｂ，３ａ，３ｂ、第１、第２、第３、第４、第５、第６の付加質量４ａ，４ｂ，５ａ，５ｂ，８，９、第１、第２の屈曲振動片６，７は、いずれも一枚の水晶板から一体に形成されている。一枚の水晶板から形成された基部１の四隅には微小な面積で固定するための固定部としてのφ０．２の孔部１０ａ，１０ｂ，１０ｃ，１０ｄが形成されている。
【００３４】
孔部１０ａ，１０ｂ，１０ｃ，１０ｄの近傍には、機械的ダンピング効果を得るためのＬ字状のスリット部１１ａ，１１ｂ，１１ｃ，１１ｄがそれぞれ所定の位置に設けられている。
【００３５】
第２、第４の音叉片２ｂ，３ｂの各ＸＹ面（表面側）には、駆動手段を構成するための駆動電極１２ａ，１３ａが設けられている。第１、第３の音叉片２ａ，３ａの各ＸＹ面上（表面側）には、モニター用の検出手段を構成するための検出電極１４ａ，１５ａが設けられている。第１、第２の屈曲振動片６，７のＸＹ面上（表面側）には、角速度印加に起因したコリオリ力による屈曲変形の検出用としての検出手段を構成するための検出電極１６ａ，１７ａが設けられている。
【００３６】
図２は駆動電極が設けられた第２の音叉片２ｂをＸＺ面で切断した断面図である。図２において、Ｘ軸方向を向く矢印は水晶からなる第２の音叉片２ｂの電気軸を示し、１２ｂは第２の音叉片２ｂを挟んで駆動電極１２ａと対向するように第２の音叉片２ｂのＸＹ面上（裏面側）に設けられた駆動電極である。１８は第２の音叉片２ｂのＹＺ面上（側面）に第２の音叉片２ｂを挟んで対向するように設けられた一対の共通電極である。１９は駆動回路の出力信号源である。
【００３７】
第４の音叉片３ｂにも第２の音叉片２ｂと同様に、駆動電極１３ａ，１３ｂ、共通電極１８が設けられている。
【００３８】
次に、第２の音叉片２ｂの駆動原理を簡単に説明する。仮に、出力信号源１９から駆動電極１２ａ，１２ｂに正極性の電圧が印加されると、図２内に示す破線の矢印方向に電界の方向が向く。これにより第２の音叉片２ｂのａｂ側は圧縮し、ｃｄ側は伸長する。また、駆動電極１２ａ，１２ｂに負極性の電圧が印加されると第２の音叉片２ｂのａｂ側は伸長し、ｃｄ側は圧縮する。
【００３９】
これらが連続的に繰り返されることで、第２の音叉片２ｂは、ＸＹ面内で１次モードで振動する。
【００４０】
同様な駆動原理により、第４の音叉片３ｂもＸＹ面内で１次モードで振動する。第２、第４の音叉片２ｂ，３ｂが１次モードで振動することにより第１、第３の音叉片２ａ，３ａも共振し、ＸＹ面内で音叉振動を開始する。
【００４１】
図３はモニター用の検出電極が設けられた第１の音叉片２ａをＸＺ面で切断した断面図である。Ｘ軸方向を向く矢印は、図２と同様に水晶からなる第１の音叉片２ａの電気軸を示し、１４ｂは第１の音叉片２ａを挟んでモニター用の検出電極１４ａと対向するように第１の音叉片２ａのＸＹ面上（裏面側）に設けられたモニター用の検出電極である。１８は図２と同様に、共通電極である。
【００４２】
第３の音叉片３ａにも第１の音叉片２ａと同様に、モニター用の検出電極１５ａ，１５ｂ、共通電極１８が設けられている。
【００４３】
次に、モニター用の検出電極１４ａ，１４ｂ、共通電極１８に現われる電荷に関して簡単に説明する。
【００４４】
第１の音叉片２ａは図２に示す第２の音叉片２ｂとともに音叉振動をしているため、第２の音叉片２ｂのａｂ側が圧縮している時は第１の音叉片２ａのｇｈ側が圧縮する。
【００４５】
また、第２の音叉片２ｂのｃｄが伸長している時は、第１の音叉片２ａのｅｆ側が伸長する。
【００４６】
これらの圧縮、伸長によりモニター用の検出電極１４ａ，１４ｂには正電荷が発生し、共通電極１８には負電荷が発生する。従って、第１の音叉片２ａにおいて、ｅｆ側が圧縮し、ｇｈ側が伸長した場合は、モニター用の検出電極１４ａ，１４ｂに負電荷が発生し、共通電極１８に正電荷が発生する。
【００４７】
図４は本発明の角速度センサとその駆動及び検出回路を接続したブロック図である。図４において、２０は差動入力型のチャージ増幅器である。差動入力型のチャージ増幅器２０は第１、第２の屈曲振動片６，７にそれぞれ設けられた検出電極１６ａ，１７ａから得られた信号を増幅し信号を９０°位相シフトさせるためのものである。２１は検波回路である。検波回路２１によりチャージ増幅器２０の出力信号を同期検波する。２２は検波回路２１により得られた検波信号を平滑するための平滑回路としてのローパスフィルタである。２３は第２、第４の音叉片２ｂ，３ｂを駆動させるための和入力型の駆動回路である。モニター用の検出電極１４ａ，１４ｂ，１５ａ，１５ｂから得られる信号を駆動回路２３に入力することにより第１、第２、第３、第４の音叉振動片２ａ，２ｂ，３ａ，３ｂを目標とする１５μｍの振動振幅となるようにフィードバック制御する。図５は、第１、第３の音叉片２ａ，３ａがＸ軸方向に、第２、第４の音叉片２ｂ，３ｂがＸ軸方向と反対の方向に駆動変形している際に、Ｚ軸周りの角速度が印加された時の第１、第２、第３、第４の音叉片２ａ，２ｂ，３ａ，３ｂ、第１、第２の屈曲振動片６、７の変形形態の一例を説明するための模式線図である。
【００４８】
図５に示すように、Ｚ軸周りの角速度が印加されたことにより、第１、第３の付加質量４ａ，５ａにはＹ軸方向に、第２、第４の付加質量４ｂ，５ｂにはＹ軸方向と反対の方向に集中的にコリオリ力が働き、このコリオリ力により、第１、第２、第３、第４の音叉片２ａ，２ｂ，３ａ，３ｂの振動振幅の対称性が崩れた１次モードの変形を呈する。この対称性の崩れた第１、第２、第３、第４の音叉片２ａ，２ｂ，３ａ，３ｂの応力状態を補正し、釣り合いを保つように第１の屈曲振動片６はＸ軸方向と反対の方向に変形し、第２の屈曲振動片７は逆にＸ軸方向に変形する。これらの変形は、印加された角速度の大きさに対応するため、第１、第２の屈曲振動片６，７にそれぞれ設けられた検出電極１６ａ，１７ａにより、印加された角速度の大きさに対応した電荷量として検出される。第１、第２、第３、第４の付加質量４ａ，４ｂ，５ａ，５ｂが設けられていることで、小さな角速度入力に対しても第１、第２の音叉部の変形量が大きくなるばかりか、第５、第６の付加質量８，９が設けられている第１、第２の屈曲振動片６，７の変形効率が向上する。これらの構成により、検出信号のさらなる高感度化が図れると同時に各付加質量４ａ，４ｂ，５ａ，５ｂ、８，９の調整により第１、第２の音叉部と第１、第２の屈曲振動部の各共振周波数の調整も容易になる。
【００４９】
図６は、第１、第２の音叉片２ａ，２ｂの間にある検出電極１６ａが設けられた第１の屈曲振動片６をＸＺ面で切断した断面図である。図６において、Ｘ軸方向を向く矢印は水晶からなる第１の屈曲振動片６の電気軸を示し、１６ｂは屈曲振動片６を挟んで検出電極１６ａと対向するように第１の屈曲振動片６のＸＹ面上（裏面側）に設けられた検出電極である。１８は第１の屈曲振動片６のＹＺ面上（側面）に第１の屈曲振動片６を挟んで対向するように設けられた一対の共通電極である。
【００５０】
同じく、第３、第４の音叉片３ａ，３ｂの間にある第２の屈曲振動片７にも、第２の屈曲振動片７を挟んで検出電極１７ａと対向するように検出電極１７ｂが設けられ、ＹＺ面上（側面）には第２の屈曲振動片７を挟んで対向するように一対の共通電極１８が設けられている。
【００５１】
次に、第１、第２の屈曲振動片６，７に図５に示すような変形が起こった時の検出電極１６ａ，１６ｂ，１７ａ，１７ｂ、共通電極１８に現われる電荷の発生状態を簡単に説明する。
【００５２】
第１、第２の音叉片２ａ，２ｂの間にある第１の屈曲振動片６のｉｊ側は圧縮し、ｋｌ側は伸長するため、検出電極１６ａ，１６ｂには負電荷が発生し、共通電極１８には正電荷が発生する。また、第３、第４の音叉片３ａ，３ｂの間にある第２の屈曲振動片７のｉｊ側は伸長し、ｋｌ側が圧縮するため、検出電極１７ａ，１７ｂには正電荷が発生し、共通電極１８には負電荷が発生する。
【００５３】
検出電極１６ａ，１６ｂから得られた電荷と検出電極１７ａ，１７ｂから得られた電荷をチャージ増幅器２０により差動増幅することにより２倍の出力が得られる。このように本実施の形態の構成により、駆動及び検出のための高精度な櫛歯構造の電極を形成することなく薄型化が図れるばかりか、付加質量が設けられているため、小さな角速度入力に対しても音叉部の変形量が大きくなり、これに呼応するように屈曲振動部の変形量も大きくなり、検出信号のさらなる高感度化が図れる。また、角速度以外の不要な成分（各方向から加わる加速度）により発生した電荷や温度による影響を排除する効果もある。
【００５４】
本実施の形態において、第１、第２、第３、第４の音叉片２ａ，２ｂ，３ａ，３ｂの１次モードの共振周波数と第１、第２の屈曲振動片６，７の１次モードの共振周波数を近接させることにより、検出感度が高くなる。
【００５５】
本実施の形態において、スリット部１１ａ，１１ｂ，１１ｃ，１１ｄが基部１に設けられていることにより、外乱振動が第１、第２の屈曲振動片６，７の１次モードの屈曲振動に混入するのを防止する効果がある。また、第１、第２の屈曲振動片６，７の１次モードの屈曲振動が基部１へ漏れるのを防止する働きもある。
【００５６】
本実施の形態においては、基部１、第１、第２、第３、第４の音叉片２ａ，２ｂ，３ａ，３ｂ、第１、第２、第３、第４、第５、第６の付加質量４ａ，４ｂ，５ａ，５ｂ，８，９と第１、第２の屈曲振動片６，７をいずれも一枚の水晶板から一体に形成した例について説明したが、圧電性を示す材料であれば単結晶材料でも多結晶材料でも構わない。
【００５７】
本実施の形態においては、第１、第２、第３、第４の音叉片２ａ，２ｂ，３ａ，３ｂの各先端から外向きに付加質量を設けた構成について説明したが、前記各先端から内向きに付加質量を設ける構成や第１、第２音叉片２ａ，２ｂにあっては付加質量を外向きにし第３、第４の音叉片３ａ，３ｂにあっては付加質量を内向きに設ける等、さまざまな構成が可能である。
【００５８】
また、本実施の形態においては、第１、第２、第３、第４の音叉片２ａ，２ｂ，３ａ，３ｂと第１、第２の屈曲振動片６，７の各先端のいずれにも付加質量が設けられた構成について説明したが、音叉片と屈曲振動片のいずれにも付加質量を設けない構成や音叉片と屈曲振動片のいずれかのみに付加質量を設ける等、さまざまな構成が可能である。
【００５９】
また、本実施の形態においては、第１、第２の音叉部に各一対の音叉片を設け、第１、第２の音叉部のそれぞれの間に各１本の屈曲振動片からなる屈曲振動部を設けた構成について説明したが、一対または複数対の音叉片と一本または複数本の屈曲振動片を適宜組み合せて設ける構成も当然可能である。
【００６０】
（実施の形態２）
図７は、本発明の角速度センサの第２の実施の形態を説明するための平面図である。図７において、図１と同一構成部分には同一番号を付して詳細な説明を省略し、異なる部分についてのみ詳述する。図７において、基部３０、第１、第２、第３、第４の音叉片３１ａ，３１ｂ，３２ａ，３２ｂ、第１、第２、第３、第４の付加質量３３ａ，３３ｂ，３４ａ，３４ｂ、第１、第２の屈曲振動片３５，３６と第５、第６の付加質量３７，３８が、恒弾性金属により一体に形成されている以外は、第１の実施の形態において説明した図１に示す形状寸法ともに同一である。
【００６１】
第２、第４の音叉片３１ｂ，３２ｂのＸＹ面上には、１次モードで駆動するための圧電体セラミックス３９，４０が接合されている。第１、第３の音叉片３１ａ，３２ａのＸＹ面上にはモニター用の圧電体セラミックス４１，４２が接合されている。第１、第２の屈曲振動片３５，３６のＸＹ面上（表面側）には、角速度の大きさに対応した電荷量を検出するための圧電体セラミックス４３，４４が接合されている。
【００６２】
図７において、第１、第２、第３、第４の音叉片３１ａ，３１ｂ，３２ａ，３２ｂ、第１、第２の屈曲振動片３５，３６の変形形態、モニター時の圧電体セラミックス４１，４２に発生する電荷、Ｚ軸周りの角速度が印加された時の圧電体セラミックス４３，４４に発生する電荷の傾向は、いずれも第１の実施の形態と同様である。
【００６３】
本実施の形態においては、基部３０、第１、第２、第３、第４の音叉片３１ａ，３１ｂ，３２ａ，３２ｂ、第１、第２、第３、第４、第５、第６の付加質量３３ａ，３３ｂ，３４ａ，３４ｂ，３７，３８及び第１、第２の屈曲振動片３５，３６を構成する材料と圧電体セラミックス３９，４０，４１，４２，４３，４４が別々の材料で構成されているため、機械的振動特性としての高いＱを有する材料と圧電定数の大きな圧電材料をそれぞれ自由に組合わせることが可能となる。
【００６４】
本実施の形態において、駆動用、モニター用、印刷された角速度の大きさに対応した電荷量の検出用にそれぞれ圧電体セラミックスを接合した例について説明したが、圧電性を示すものであれば各種の薄膜構成を採用することも可能である。
【００６５】
（実施の形態３）
図８は、本発明の角速度センサの第３の実施の形態を説明するための平面図である。図８において、駆動方向をＸ軸方向、コリオリ力が発生する方向をＹ軸、角速度Ωの入力軸をＺ軸とする。
【００６６】
図８において、５０は厚さ（Ｚ軸方向）０．５ｍｍ、長さ（Ｙ軸方向）１５ｍｍ、幅（Ｘ軸方向）１５ｍｍの圧電体セラミックスからなる基部、５１は基部５０からＹ軸方向と反対の方向に向かって延出した厚さ（Ｚ軸方向）０．５ｍｍ、Ｙ軸方向に長さ１５ｍｍ、幅（Ｘ軸方向）３．５ｍｍの圧電体セラミックスからなる振動片、５２は振動片５１の先端からＸ軸方向と反対の方向に延出した厚さ（Ｚ軸方向）０．５ｍｍ、長さ５ｍｍ、幅（Ｙ軸方向）３．５ｍｍの圧電体セラミックスからなる付加質量部である。振動片５１のＸＹ面（表面側）には、幅方向の両端にそれぞれ駆動手段兼検出手段を構成するための電極５３ａ，５４ａが設けられている。
【００６７】
図９は電極５３ａ，５４ａが設けられた振動片５１をＸＺ面で切断した断面図である。図９において、Ｚ軸方向を向く矢印は圧電体セラミックスからなる振動片５１の分極方向を示し、５３ｂ，５４ｂは振動片５１を挟んで電極５３ａ，５４ａと対向するように振動片５１のＸＹ面上（裏面側）に設けられた共通電極である。５５は駆動回路の出力信号源である。
【００６８】
次に、振動片５１の駆動原理を簡単に説明する。仮に、出力信号源５５から電極５３ａ，５４ａにそれぞれ正極性、負極性の電圧が印加されると、振動片５１の電極５３ａ，５３ｂが設けられている側はＹ軸方向に伸長、電極５４ａ，５４ｂが設けられている側はＹ軸方向に圧縮する。また、電極５３ａ，５４ａにそれぞれ負極性、正極性の電圧が印加されると、振動片５１の電極５３ａ，５３ｂが設けられている側はＹ軸方向に圧縮し、電極５４ａ，５４ｂが設けられている側はＹ軸方向に伸長する。
【００６９】
これらが連続的に繰り返されることで、振動片５１は、ＸＹ面内で１次モードで振動する。
【００７０】
図１０は本発明の角速度センサとその駆動及び検出回路を接続したブロック図である。図１１は、振動片５１がＸ軸方向に駆動変形している際に、図１０に示すようなＺ軸周りの角速度が印加された時の振動片５１の変形形態の一例を説明するための模式線図である。図１２は、振動片５１がＸ軸方向に駆動変形している際に、図１０に示すようなＺ軸周りの角速度が印加された時のＡ点、Ｂ点の電圧の変化状態の説明図である。図１１、図１２において、実線は角速度の印加が無い場合を示し、破線は角速度の印加が有る場合を示す。図１０において、５６は自励発振式駆動回路、５７，５８は抵抗、５９は検出回路としての加算増幅器である。自励発振式駆動回路５６より抵抗５７，５８を介して電極５３ａ，５４ａへ逆位相の電圧を供給することにより、前述のように連続的な振動が発生する。図１１に示すように振動片５１の電極５３ａ，５４ａにそれぞれ正極性、負極性の電圧を印加し振動片５１を振動させた状態の時、図１０に示すようなＺ軸周りの角速度が印加されると付加質量部５２にＹ軸方向と反対方向に集中的にコリオリ力が働き、振動片５１の電極５３ａ，５３ｂが設けられている側をＹ軸方向により伸長させ、電極５４ａ，５４ｂが設けられている側をＹ軸方向により圧縮させる変形となる。このような変形により、電極５３ａ，５３ｂが設けられている振動片５１のＺ軸方向側は、より圧縮しインピーダンスが高くなる。逆に電極５４ａ，５４ｂが設けられている振動片５１のＺ軸方向側は、より伸長しインピーダンスが低くなる。これらの変化を図１０に示すＡ点、Ｂ点の電圧の変化として捉えた様子を示すのが図１２である。
【００７１】
前述のＡ点、Ｂ点のそれぞれの電圧を加算増幅器５９に加えることで、印加された角速度の大きさに対応した最終出力が得られる。
【００７２】
本実施の形態により、駆動及び検出のための高精度な櫛歯構造の電極を形成することなく薄型化且つ高感度化が図れるばかりか、振動片を駆動させる駆動電圧に角速度の印加に起因した検出信号が重畳する状態で検出可能になる。
【００７３】
なお本実施の形態においては、一本の振動片とその先端に設けた付加質量部を用いた例について説明したが、このような構造体を対にして音叉構成とすることも当然可能である。これにより、角速度が印加されると両付加質量部に互いに逆向きのコリオリ力が働き、２倍の出力信号を得られる。さらに、音叉構成を二対用いてＨ型構成とすることも可能である。これにより、さらなる出力信号の増加が期待できる。また、第１の実施の形態でもすでに述べたように音叉部の間に屈曲振動片が設けられた構成（ただし、必ずしも第１、第２の音叉部を共に備えていなければならないという狭い意味ではない）、付加質量の有無及び付加質量の形成方向が考慮に入れられた構成等、様々な構成を用いることも可能である。
【００７４】
（実施の形態４）
図１３は、本発明の角速度センサの第４の実施の形態を説明するための斜視図である。図１４は、振動片がＸＹ面内で駆動変形している際に、図１３に示すようなＺ軸周りの角速度が印加された時の振動片の変形形態の一例を説明するための模式線図である。図１３において、駆動方向をＸ軸方向、コリオリ力が発生する方向をＹ軸、角速度Ωの入力軸をＺ軸とする。図１４において、実線は角速度の印加が無い場合を示し、破線は角速度の印加が有る場合を示す。本実施の形態において、振動片を駆動させる駆動電圧に角速度の印加に起因した検出信号が重畳する状態で検出を可能にする点では、第３の実施の形態と基本技術思想を同じにするため、異なる部分についてのみ詳述する。図１３において、６０はＹ軸方向に伸びた圧電体セラミックスから形成された振動片、６１，６２は前記振動片６０の両端からそれぞれＸ軸方向と反対の方向及びＸ軸方向にそれぞれ延出した圧電体セラミックスから形成された第１、第２の付加質量部、６３ａ，６３ｂは振動片６０をＹ軸上で支持するために前記振動片６０の一方のＸＹ面且つ第１の付加質量部６１寄り及び第２の付加質量部６２寄りにそれぞれ設けられた第１、第２の支持点、６３ｃ，６３ｄは前記振動片６０を挟んで第１、第２の支持点６３ａ，６３ｂにそれぞれ対向するように前記振動片６０の他方のＸＹ面に設けられた第３、第４の支持点、６４ａ、６４ｂは振動片６０のＸＹ面（表面側）の幅方向（Ｘ軸方向）の両端且つ第１の付加質量部６１と第１の支持点６３ａの間にそれぞれ設けられた駆動手段兼検出手段としての第１、第２の電極、６５ａ，６５ｂは振動片６０のＸＹ面（表面側）の幅方向（Ｘ軸方向）の両端且つ第２の付加質量部６２と第２の支持点６３ｂの間にそれぞれ設けられた駆動手段兼検出手段としての第３、第４の電極、６６は固定部、６７ａ，６７ｂ，６７ｃ，６７ｄは第１、第２、第３、第４の支持部である。第１、第３の支持点６３ａ，６３ｃを結ぶ直線はＺ軸上にあり且つ前記第１、第３の支持点６３ａ，６３ｃからＺ軸方向及びＺ軸方向と反対の方向にそれぞれ第１、第３の支持部６７ａ，６７ｃが延出しており、第１、第３の支持部６７ａ，６７ｃの端はそれぞれ固定部６６に固定されている。第２、第４の支持点６３ｂ，６３ｄを結ぶ直線はＺ軸上にあり且つ前記第２、第４の支持点６３ｂ，６３ｄからＺ軸方向及びＺ軸方向と反対の方向にそれぞれ第２、第４の支持部６７ｂ，６７ｄが延出しており、第２、第４の支持部６７ｂ，６７ｄの端はそれぞれ固定部６６に固定されている。
【００７５】
振動片６０を挟んで第１、第２、第３、第４の電極６４ａ，６４ｂ，６５ａ，６５ｂに対向するように振動片６０のＸＹ面上（裏面側）に共通電極が設けられており、第１と第３の電極６４ａ，６５ａは同位相、第２と第４の電極６４ｂ，６５ｂは同位相及び第１と第２の電極６４ａ，６４ｂは互いに逆位相、第３、第４の電極６５ａ，６５ｂは互いに逆位相になるように電圧を供給することにより、第１、第２の支持点６３ａ，６３ｂを振動の節にしてＸＹ面内で連続的な１次モードの屈曲振動が振動片６０に発生する。図１４に示すように、例えば、振動片６０の第２と第４の電極６４ｂ，６５ｂにそれぞれ正極性の電圧を印加し、第１と第３の電極６４ａ，６５ａにそれぞれ負極性の電圧を印加し振動片６０を振動させた状態の時、図１３に示すようなＺ軸周りの角速度が印加されると、第１の付加質量部６１にＹ軸方向に集中的にコリオリ力が働き、振動片６０の第２の電極６４ｂが設けられている側をＹ軸方向により伸長させ、第１の電極６４ａが設けられている側をＹ軸方向により圧縮させる変形となる。また、第２の付加質量部６２にＹ軸方向と反対方向に集中的にコリオリ力が働き、振動片６０の第４の電極６５ｂが設けられている側をＹ軸方向にいくらか圧縮させ、第３の電極６５ａが設けられている側をＹ軸方向にいくらか伸長させる変形となる。このような変形により、第２、第３の電極６４ｂ，６５ａが設けられている振動片６０のＺ軸方向側は、圧縮されることでインピーダンスが高くなる。逆に第１、第４の電極６４ａ，６５ｂが設けられている振動片６０のＺ軸方向側は、伸長されることでインピーダンスが低くなる。これらの変化を検出することで印加された角速度の大きさに対応した最終出力が得られる。この構成により、駆動及び検出のための高精度な櫛歯構造の電極を形成することなく薄型化且つ高感度化が図れるばかりか、振動片を駆動させる駆動電圧に角速度の印加に起因した検出信号が重畳する状態で検出可能になる。
【００７６】
本実施の形態においては、振動片６０のＺ軸方向の寸法がＸ軸方向の寸法に比べて小さい場合について説明したが、これとは逆の構成も当然可能である。
【００７７】
また本実施の形態においては、振動片６０と第１、第２の付加質量部６１，６２が一体の圧電体セラミックスから形成された例について説明したが、水晶板により一体に構成したり、恒弾性金属材料、酸化物材料または高弾性高分子材料により振動片と第１、第２の付加質量部を一体に形成し、この振動片の上に圧電体セラミックスを接合したり、圧電性を示す各種の薄膜を表面に形成するような構成でも当然本発明の技術思想を達成可能である。
【００７８】
【発明の効果】
以上のように本発明は、ＸＹ面内に設けられた基部と、ＸＹ面内において前記基部からＹ軸方向と反対の方向に延出した少なくとも一対の音叉片からなる第１の音叉部と、前記第１の音叉部に相対向するように前記基部からＹ軸方向に延出した少なくとも一対の音叉片からなる第２の音叉部と、前記第１の音叉部を構成する対をなした音叉片の間にあり且つ前記基部からＹ軸方向と反対の方向に延出した少なくとも１本以上の屈曲振動片からなる第１の屈曲振動部と、前記第２の音叉部を構成する対をなした音叉片の間にあり且つ前記第１の屈曲振動部に相対向するように前記基部からＹ軸方向に延出した少なくとも１本以上の屈曲振動片からなる第２の屈曲振動部と、前記第１、第２の音叉部を構成する音叉片をＸ軸方向またはＸ軸方向と反対の方向へ屈曲振動させるために前記音叉片に設けられた駆動手段と、Ｚ軸周りの角速度が印加された時、Ｙ軸方向またはＹ軸方向と反対の方向に働くコリオリ力の大きさに応じて変化する前記音叉片の屈曲変形と釣り合いを保つようにＸ軸方向またはＸ軸方向と反対の方向に屈曲変形する前記屈曲振動片の変形量を検出するために前記屈曲振動片に設けられた検出手段とを備えることにより、駆動及び検出のための高精度な櫛歯構造の電極を形成することなく薄型且つ高感度な角速度センサが得られる。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態の角速度センサを説明するための平面図
【図２】同角速度センサの駆動電極が設けられた音叉片をＸＺ面で切断した説明図
【図３】同角速度センサのモニター用の検出電極が設けられた音叉片をＸＺ面で切断した説明図
【図４】同角速度センサとその駆動回路及び検出回路を接続したブロック図
【図５】同角速度センサに角速度が印加された時の音叉片と屈曲振動片の変形形態の模式図
【図６】同角速度センサの検出電極が設けられた屈曲振動片をＸＺ面で切断した説明図
【図７】本発明の第２の実施の形態の角速度センサを説明するための平面図
【図８】本発明の第３の実施の形態の角速度センサを説明するための平面図
【図９】同角速度センサの電極が設けられた振動片をＸＺ面で切断した説明図
【図１０】同角速度センサとその駆動回路及び検出回路を接続したブロック図
【図１１】同角速度センサに角速度が印加された時の振動片の変形形態の模式図
【図１２】同角速度センサに角速度が印加された時のＡ点、Ｂ点の電圧の変化状態の説明図
【図１３】本発明の第４の実施の形態の角速度センサを説明するための斜視図
【図１４】同角速度センサに角速度が印加された時の振動片の変形形態の模式図
【符号の説明】
１，３０，５０基部
２ａ，３１ａ第１の音叉片
２ｂ，３１ｂ第２の音叉片
３ａ，３２ａ第３の音叉片
３ｂ，３２ｂ第４の音叉片
４ａ，３３ａ第１の付加質量
４ｂ，３３ｂ第２の付加質量
５ａ，３４ａ第３の付加質量
５ｂ，３４ｂ第４の付加質量
６，３５第１の屈曲振動片
７，３６第２の屈曲振動片
８，３７第５の付加質量
９，３８第６の付加質量
１０ａ，１０ｂ，１０ｃ，１０ｄ孔部
１１ａ，１１ｂ，１１ｃ，１１ｄスリット部
１２ａ，１２ｂ，１３ａ，１３ｂ駆動電極
１４ａ，１４ｂ，１５ａ，１５ｂモニター用の検出電極
１６ａ，１６ｂ，１７ａ，１７ｂ角速度検出用の検出電極
１８，５３ｂ，５４ｂ共通電極
１９，５５駆動回路の出力信号源
２０チャージ増幅器
２１検波回路
２２ローパスフィルタ
２３駆動回路
３９，４０，４１，４２，４３，４４圧電体セラミックス
５１，６０振動片
５２付加質量部
５３ａ，５４ａ電極
５６自励発振式駆動回路
５７，５８抵抗
５９検出回路
６１第１の付加質量部
６２第２の付加質量部
６３ａ第１の支持点
６３ｂ第２の支持点
６３ｃ第３の支持点
６３ｄ第４の支持点
６４ａ第１の電極
６４ｂ第２の電極
６５ａ第３の電極
６５ｂ第４の電極
６６固定部
６７ａ第１の支持部
６７ｂ第２の支持部
６７ｃ第３の支持部
６７ｄ第４の支持部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an angular velocity sensor used in, for example, automobile attitude control, navigation, camera shake prevention, remote control for remote control, and the like.
[0002]
[Prior art]
As a conventional thin angular velocity sensor, one described in JP-A-10-170276 is known. This angular velocity sensor has a structure in which an additional mass portion at the center is supported in a plane by a thin beam. In addition, when the angular velocity is applied around an axis perpendicular to the plane and a driving unit for driving the additional mass unit in a plane, the displacement amount by which the additional mass unit is displaced by the Coriolis force acting on the additional mass unit is determined. Both detection parts for detection are composed of comb-shaped electrodes.
[0003]
[Problems to be solved by the invention]
Although such an angular velocity sensor can realize a relatively thin structure, in order to drive it, the electrodes having a comb structure must be opposed to each other and driven by a suction force acting on these electrodes. Therefore, these electrodes must be formed with extremely small gaps and high accuracy.
[0004]
In addition, in order to be able to detect a weak signal with high accuracy, the opposing comb-teeth structure electrodes must be formed with very small gaps and high accuracy, and a large number of opposing comb teeth are provided. It had the problem of having to.
[0005]
The present invention solves this problem, and an object of the present invention is to provide a thin and highly sensitive angular velocity sensor without forming a highly accurate comb-teeth structure electrode for driving and detection.
[0006]
[Means for Solving the Problems]
Relative to the first tuning fork, a base provided in the XY plane, a first tuning fork composed of at least a pair of tuning forks extending in the direction opposite to the Y-axis direction from the base in the XY plane, and The second tuning fork piece made of at least a pair of tuning fork pieces extending in the Y-axis direction from the base portion so as to face the tuning fork pieces constituting the first tuning fork piece and the base portion Between the first bending vibration part made up of at least one bending vibration piece extending in the direction opposite to the Y-axis direction from the first tuning vibration fork piece forming the second tuning fork part, and A second flexural vibration part comprising at least one flexural vibration piece extending in the Y-axis direction from the base so as to face the first flexural vibration part; and the first and second tuning fork parts The tuning fork piece that constitutes the bending vibration in the X-axis direction or the direction opposite to the X-axis direction Therefore, when the driving means provided in the tuning fork piece and the angular velocity around the Z axis are applied, the tuning fork that changes according to the magnitude of the Coriolis force acting in the Y axis direction or the direction opposite to the Y axis direction. Detecting means provided on the bending vibration piece for detecting the deformation amount of the bending vibration piece that is bent and deformed in the X-axis direction or in a direction opposite to the X-axis direction so as to keep a balance with the bending deformation of the piece. It is characterized by that. With this configuration, a thin and highly sensitive angular velocity sensor can be obtained without forming a highly accurate comb-teeth structure electrode for driving and detection.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
According to a first aspect of the present invention, there is provided a first portion comprising a base portion provided in the XY plane and at least a pair of tuning fork pieces extending from the base portion in the direction opposite to the Y-axis direction in the XY plane. A tuning fork part; a second tuning fork part comprising at least a pair of tuning fork pieces extending in the Y-axis direction from the base part so as to face the first tuning fork part; and a pair constituting the first tuning fork part The first tuning fork portion is composed of at least one bending vibration piece that is between the tuning fork pieces that are formed and extends from the base portion in a direction opposite to the Y-axis direction, and the second tuning fork portion. A second bending vibration comprising at least one bending vibration piece extending in the Y-axis direction from the base so as to be between the paired tuning fork pieces and opposite to the first bending vibration portion. Part and the tuning fork pieces constituting the first and second tuning fork parts are arranged in the X-axis direction or When the driving means provided in the tuning fork piece to bend and vibrate in the direction opposite to the axial direction and the angular velocity around the Z axis are applied, the Coriolis force acting in the Y axis direction or the direction opposite to the Y axis direction is applied. The bending vibration piece for detecting the deformation amount of the bending vibration piece that is bent and deformed in the X-axis direction or the direction opposite to the X-axis direction so as to keep balance with the bending deformation of the tuning fork piece that changes according to the size. Therefore, it is possible to reduce the thickness and increase the sensitivity without forming a high-precision comb-teeth structure electrode for driving and detection.
[0008]
The invention according to claim 2 is the invention according to claim 1, wherein the tip of each of the pair of tuning fork pieces constituting the first and second tuning fork parts is the X axis direction or the direction opposite to the X axis direction. The tuning fork pieces on both sides of the first and second tuning fork portions are centered on the symmetry axes of the first and second tuning fork portions and are opposite to each other and on the same side. The first additional mass portion is formed so as to extend in the same direction, and each one of the bending vibration pieces constituting the first and second bending vibration portions is on the axis of symmetry of the tuning fork portion. Since the second additional mass part is formed so as to project from the tip of the bending vibration piece in the X-axis direction and the direction opposite to the X-axis direction, the amount of deformation of the tuning fork part can be reduced even with a small angular velocity input. In response to this, the amount of deformation of the flexural vibration part also increases, which further increases the detection signal. Cathodic has the effect that it becomes easy to adjust the respective resonance frequencies of the bending vibration unit tuning fork portion by can be reduced at the same time adjusting the added mass parts.
[0009]
According to a third aspect of the present invention, in the first or second aspect of the present invention, the resonance frequency of the first and second tuning fork portions and the resonance frequency of the first and second flexural vibration portions are close to each other. Therefore, it has the effect that the sensitivity of the detection signal can be increased.
[0010]
According to a fourth aspect of the present invention, in the first or second aspect of the present invention, differential detection processing is performed on each detection signal detected by the detection means provided in the first and second bending vibration portions. Since the processing circuit is configured to be connected to the detection means, it has an effect that a disturbance signal based on an acceleration component applied from the three axis directions of the X axis direction, the Y axis direction, and the Z axis direction can be removed.
[0011]
According to a fifth aspect of the present invention, in the first aspect of the invention, the base portion, the first and second tuning fork portions, and the first and second bending vibration portions provided in the XY plane are made of a piezoelectric material. Since the structure is integrally formed, it has an effect that an integrated structure can be formed very easily from a flat plate having uniform piezoelectric characteristics.
[0012]
According to a sixth aspect of the present invention, in the second aspect of the present invention, the base portion, the first and second tuning fork portions, the first and second flexural vibration portions and the first and second bending vibration portions provided in the XY plane. Since the additional mass portion 2 is formed integrally with a piezoelectric material, it has an effect that an integrated structure can be formed very easily from a flat plate having uniform piezoelectric characteristics.
[0013]
According to a seventh aspect of the present invention, in the first aspect of the present invention, the base portion, the first and second tuning fork portions, and the first and second bending vibration portions provided in the XY plane are made of a constant elastic metal. A layer made of a piezoelectric material is formed on the XY plane of at least the first and second tuning fork portions and the first and second bending vibration portions. Therefore, it is possible to freely combine a material having a high Q as a mechanical vibration characteristic and a piezoelectric material having a large piezoelectric constant.
[0014]
According to an eighth aspect of the present invention, in the second aspect of the present invention, a base portion, first and second tuning fork portions, first and second flexural vibration portions and first and second portions provided in the XY plane are provided. The additional mass portion 2 is formed of a constant elastic metal material, an oxide material, or a highly elastic polymer material, and is at least on the XY plane of the first and second tuning fork portions and the first and second bending vibration portions. Has a structure in which a layer made of a piezoelectric material is provided, and thus has an effect that a material having a high Q as a mechanical vibration characteristic and a piezoelectric material having a large piezoelectric constant can be freely combined.
[0015]
Also , A base provided in the XY plane, a vibrating piece extending in the direction opposite to the Y-axis direction from the base in the XY plane, and a direction opposite to the X-axis direction or the X-axis direction from the tip of the vibrating piece And an additional mass portion formed so as to extend in at least one of the above-described directions, and the vibrating piece for bending and vibrating the vibrating piece in the X-axis direction or the direction opposite to the X-axis direction. X-axis direction or X-axis direction of the resonator element that changes according to the magnitude of the Coriolis force acting in the Y-axis direction or the direction opposite to the Y-axis direction when an angular velocity around the Z-axis is applied. In order to detect the increase / decrease amount of the amplitude of the bending vibration in the direction opposite to the above, a detecting means that is also used as the driving means provided in the vibrating piece is provided. Thin and high without forming a toothed electrode Doka is not only attained, an effect that the detection signal due to the application of the angular velocity to the driving voltage for driving the vibration piece becomes detectable in a state of superposition.
[0016]
In the above configuration Since the base portion, the vibrating piece and the additional mass portion provided in the XY plane are integrally formed of a piezoelectric material, it has an effect that an integrated structure can be formed very easily from a flat plate having uniform piezoelectric characteristics. .
[0017]
In the above configuration The base provided in the XY plane, the vibrating piece, and the additional mass portion are formed of a constant elastic metal material, an oxide material, or a high elastic polymer material, and at least on the XY plane of the vibrating piece is made of a piezoelectric material. Since the structure is provided with a layer, it has an effect that a material having a high Q as a mechanical vibration characteristic and a piezoelectric material having a large piezoelectric constant can be freely combined.
[0018]
Also The vibrating piece extending in the Y-axis direction, the additional mass portion extending from either end of the vibrating piece in either the X-axis direction or the direction opposite to the X-axis direction, or both directions, and the vibration In order to support the piece symmetrically on the Y axis, first and second support points provided on one XY plane of the vibrating piece, and third and second provided on the other XY plane of the vibrating piece 4 support points, and first and third support portions extending in the Z-axis direction and the direction opposite to the Z-axis direction so as to be collinear with the first and third support points, The second and fourth support portions extending in the Z-axis direction and the direction opposite to the Z-axis direction so as to be on the same straight line from the second and fourth support points, respectively, and the vibration piece are connected to the first and second vibration pieces. The second, third, and fourth support points are arranged on the vibrating element to bend and vibrate in the first-order mode in the XY plane with the vibration nodes as vibration nodes. X-axis direction or X-axis of the resonator element that changes according to the magnitude of the Coriolis force acting in the Y-axis direction or the direction opposite to the Y-axis direction when an angular velocity around the Z-axis is applied. A high-accuracy comb for driving and detecting because it comprises a detecting means that is also used as the driving means provided in the vibrating element in order to detect the amount of increase / decrease in the amplitude of bending vibration in the direction opposite to the direction Not only can the thickness and the sensitivity be increased without forming a tooth-structured electrode, but also the detection can be performed in a state where a detection signal resulting from the application of angular velocity is superimposed on the driving voltage for driving the resonator element.
[0019]
In the above configuration Since the vibration piece and the additional mass portion are integrally formed of a piezoelectric material, the vibration piece and the additional mass portion have an effect that an integrated structure can be formed very easily from a flat plate having uniform piezoelectric characteristics.
[0020]
In the above configuration The vibrating piece and the additional mass portion are formed of a constant elastic metal material, an oxide material, or a highly elastic polymer material, and at least a layer made of a piezoelectric material is provided on the XY plane of the vibrating piece. It has an effect that a material having a high Q as a mechanical vibration characteristic and a piezoelectric material having a large piezoelectric constant can be freely combined.
[0021]
Also , A base portion provided in the XY plane, a pair of tuning fork pieces extending from the base portion in the XY plane, and an X axis direction or a direction opposite to the X axis direction from each tip of the pair of tuning fork pieces. An additional mass portion formed so as to extend in any one direction, and the pair of tuning fork pieces are provided in the pair of tuning fork pieces in order to bend and vibrate in the X-axis direction or the direction opposite to the X-axis direction. X-axis direction or X-axis of the pair of tuning fork pieces that change according to the magnitude of the Coriolis force acting in the Y-axis direction or the direction opposite to the Y-axis direction when an angular velocity around the Z-axis is applied. In order to detect the increase / decrease amount of the amplitude of the bending vibration in the direction opposite to the axial direction, it is provided with a detection means that is also used as the drive means provided in the pair of tuning fork pieces. Thinner without forming high-precision comb-shaped electrodes One high sensitivity is not only attained, an effect that the detection signal due to the application of the angular velocity to the driving voltage for driving the vibration piece becomes detectable in a state of superposition.
[0022]
In the above configuration The base portion, the pair of tuning fork pieces and the additional mass portion provided in the XY plane are integrally formed of a piezoelectric material, so that an integrated structure can be formed very easily from a flat plate having uniform piezoelectric characteristics. Have
[0023]
In the above configuration The base portion, the pair of tuning fork pieces and the additional mass portion provided in the XY plane are formed of a constant elastic metal material, an oxide material, or a highly elastic polymer material, and at least on the XY plane of the pair of tuning fork pieces. Since the structure is provided with a layer made of a piezoelectric material, it has an effect that a material having a high Q as a mechanical vibration characteristic and a piezoelectric material having a large piezoelectric constant can be freely combined.
[0024]
Also A base portion provided in the XY plane, at least a pair of tuning fork pieces extending in the Y-axis direction from the base portion in the XY plane, and on the X-axis direction side with respect to the symmetry axis of the pair of tuning fork pieces. Both the tuning fork piece and the tuning fork piece on the side opposite to the X-axis direction are either in the X-axis direction or the direction opposite to the X-axis direction from the tip and on the same side. Are between an additional mass portion formed so as to extend in the same direction, at least one bending vibration piece extending between the pair of tuning fork pieces and extending in the Y-axis direction from the base portion, and the tuning fork. When the driving means provided in the tuning fork piece to cause the piece to bend and vibrate in the X-axis direction or the direction opposite to the X-axis direction and an angular velocity around the Z-axis are applied, the Y-axis direction or the Y-axis direction is opposite. The above changes depending on the magnitude of the Coriolis force acting in the direction of Detecting means provided on the bending vibration piece for detecting the amount of deformation of the bending vibration piece that is bent and deformed in the X-axis direction or in a direction opposite to the X-axis direction so as to keep balance with the bending deformation of the fork piece; Therefore, it is possible to reduce the thickness and increase the sensitivity without forming a highly accurate comb-teeth structure electrode for driving and detection.
[0025]
In the above configuration Since the base, tuning fork piece, additional mass part and bending vibration piece provided in the XY plane are made of a single piece of piezoelectric material, an integrated structure can be formed very easily from a flat plate with uniform piezoelectric characteristics. It has the action.
[0026]
In the above configuration The base, tuning fork piece, additional mass part and bending vibration piece provided in the XY plane are formed of a constant elastic metal material, oxide material or high elastic polymer material, and at least the XY of the tuning fork piece and the bending vibration piece. Since the surface is provided with a layer made of a piezoelectric material, it has an effect that a material having a high Q as a mechanical vibration characteristic and a piezoelectric material having a large piezoelectric constant can be freely combined. .
[0027]
Also , Two base portions provided in the XY plane, a first support portion formed so as to connect the respective base portions in the Y-axis direction in the XY plane, and a central portion of the first support portion Extending from the tip of the second support portion in the direction opposite to the Y-axis direction and the Y-axis direction. The first and second vibrating bars, the third and fourth vibrating bars extending in the Y-axis direction and the direction opposite to the Y-axis direction from the tip of the third support portion, and the first and second An additional mass part formed so as to extend from each tip of the third and fourth vibrating pieces in either the X-axis direction or the direction opposite to the X-axis direction, and positive polarity or negative electrode The first and second vibrating bars are vibrated in the X-axis direction or in the direction opposite to the X-axis direction with the drive signal having the characteristic and the third and fourth vibrating bars are 1. When driving means provided on the first, second, third, and fourth vibrating bars to vibrate simultaneously in the opposite direction to the first and second vibrating bars and an angular velocity around the Z axis are applied. , Opposite to the X-axis direction or the X-axis direction of the first, second, third, and fourth vibrating bars, which change according to the magnitude of the Coriolis force acting in the Y-axis direction or the direction opposite to the Y-axis direction. In order to detect the amount of increase / decrease in the amplitude of the bending vibration in the direction, the first, second, third, and fourth vibrating bars are provided with detection means that also serves as the driving means. In addition, it is possible to reduce the thickness and increase the sensitivity without forming a high-precision comb-teeth structure electrode for detection, and the detection signal resulting from the application of the angular velocity is superimposed on the driving voltage for driving the resonator element. Has the effect of being detectable.
[0028]
In the above configuration The base portion provided in the XY plane, the first, second, and third support portions, the first, second, third, and fourth vibrating bars and the additional mass portion are integrally formed of a piezoelectric material. Since it is configured, it has an effect that a monolithic structure can be formed very easily from a flat plate having uniform piezoelectric characteristics.
[0029]
In the above configuration , A base portion provided in the XY plane, first, second, and third support portions, first, second, third, and fourth vibrating bars and an additional mass portion are made of a constant elastic metal material and an oxide material. Alternatively, since it is formed of a highly elastic polymer material and a layer made of a piezoelectric material is provided on at least the XY plane of the first, second, third, and fourth vibrating pieces, mechanical vibration characteristics As a result, it is possible to freely combine a material having a high Q and a piezoelectric material having a large piezoelectric constant.
[0030]
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0031]
(Embodiment 1)
FIG. 1 is a plan view for explaining a first embodiment of the angular velocity sensor of the present invention. In FIG. 1, the driving direction is the X-axis direction, the direction in which the Coriolis force is generated is the Y-axis, and the input axis of the angular velocity Ω is the Z-axis. In FIG. 1, reference numeral 1 denotes a base portion made of a quartz crystal plate as a piezoelectric body having a thickness (Z-axis direction) of 0.2 mm, a length (Y-axis direction) of 20 mm, and a width (X-axis direction) of 13.3 mm.
[0032]
First and second tuning fork pieces 2a and 2b extend from the base 1 in the direction opposite to the Y-axis to form a first tuning fork piece, and are opposed to the first and second tuning fork pieces 2a and 2b, respectively. The third and fourth tuning fork pieces 3a and 3b extend from the base portion 1 in the Y-axis direction to form a second tuning fork portion. First and second additional masses 4a and 4b extend from the tips of the first and second tuning fork pieces 2a and 2b so as to be symmetric in the X-axis direction and the direction opposite to the X-axis direction, respectively. Similarly, third and fourth additional masses 5a and 5b extend from the tips of the third and fourth tuning fork pieces 3a and 3b so as to be symmetrical in the X-axis direction and the opposite direction to the X-axis direction, respectively. The first, second, third, and fourth additional masses 4a, 4b, 5a, and 5b constitute a first additional mass unit.
[0033]
The first bending vibration piece 6 extends from the base portion 1 on the axis of symmetry of the first tuning fork portion (that is, passing between the first and second tuning fork pieces 2a and 2b) in the direction opposite to the Y-axis direction. A first bending vibration part is configured. Similarly, the second bending vibration piece 7 extends in the Y-axis direction from the base portion 1 on the symmetry axis of the second tuning fork portion (that is, between the third and fourth tuning fork pieces 3a and 3b). A bending vibration part is formed. Fifth and sixth additional masses 8 and 9 are provided so as to project from the tips of the first and second bending vibration pieces 6 and 7 in the X-axis direction and in the direction opposite to the X-axis direction. The mass part is configured. Base 1, first, second, third, fourth tuning fork pieces 2a, 2b, 3a, 3b, first, second, third, fourth, fifth, sixth added masses 4a, 4b, 5a , 5b, 8, 9 and the first and second bending vibration pieces 6 and 7 are integrally formed from a single quartz plate. Holes 10a, 10b, 10c, and 10d having a diameter of 0.2 are formed at the four corners of the base portion 1 formed from a single quartz plate as fixing portions for fixing with a small area.
[0034]
In the vicinity of the holes 10a, 10b, 10c, and 10d, L-shaped slit portions 11a, 11b, 11c, and 11d for obtaining a mechanical damping effect are provided at predetermined positions, respectively.
[0035]
Drive electrodes 12a and 13a for constituting drive means are provided on the XY planes (surface side) of the second and fourth tuning fork pieces 2b and 3b. Detection electrodes 14a and 15a for constituting a detection means for monitoring are provided on each XY plane (front side) of the first and third tuning fork pieces 2a and 3a. Detection electrodes 16a and 17a for configuring detection means for detecting bending deformation due to Coriolis force caused by application of angular velocity are provided on the XY plane (front side) of the first and second bending vibration pieces 6 and 7. Is provided.
[0036]
FIG. 2 is a cross-sectional view of the second tuning fork piece 2b provided with drive electrodes, cut along the XZ plane. In FIG. 2, the arrow pointing in the X-axis direction indicates the electric axis of the second tuning fork piece 2b made of quartz, and 12b is the second tuning fork piece so as to face the drive electrode 12a across the second tuning fork piece 2b. This is a drive electrode provided on the XY plane (back side) of 2b. Reference numeral 18 denotes a pair of common electrodes provided on the YZ plane (side surface) of the second tuning fork piece 2b so as to face each other with the second tuning fork piece 2b interposed therebetween. Reference numeral 19 denotes an output signal source of the driving circuit.
[0037]
Similarly to the second tuning fork piece 2b, the fourth tuning fork piece 3b is also provided with drive electrodes 13a and 13b and a common electrode 18.
[0038]
Next, the driving principle of the second tuning fork piece 2b will be briefly described. If a positive voltage is applied from the output signal source 19 to the drive electrodes 12a and 12b, the direction of the electric field is directed in the direction of the broken arrow shown in FIG. As a result, the ab side of the second tuning fork piece 2b is compressed and the cd side is expanded. When a negative voltage is applied to the drive electrodes 12a and 12b, the ab side of the second tuning fork piece 2b expands and the cd side compresses.
[0039]
By repeating these continuously, the second tuning fork piece 2b vibrates in the primary mode in the XY plane.
[0040]
According to the same driving principle, the fourth tuning fork piece 3b also vibrates in the primary mode in the XY plane. When the second and fourth tuning fork pieces 2b and 3b vibrate in the primary mode, the first and third tuning fork pieces 2a and 3a also resonate and start tuning fork vibration in the XY plane.
[0041]
FIG. 3 is a cross-sectional view of the first tuning fork piece 2a provided with a detection electrode for monitoring, taken along the XZ plane. The arrow pointing in the X-axis direction indicates the electric axis of the first tuning fork piece 2a made of crystal as in FIG. 2, and 14b faces the detection electrode 14a for monitoring across the first tuning fork piece 2a. This is a detection electrode for monitoring provided on the XY plane (back side) of the first tuning fork piece 2a. 18 is a common electrode as in FIG.
[0042]
Similarly to the first tuning fork piece 2a, the third tuning fork piece 3a is provided with detection electrodes 15a and 15b for monitoring and a common electrode 18.
[0043]
Next, the charges appearing on the detection electrodes 14a and 14b for monitoring and the common electrode 18 will be briefly described.
[0044]
Since the first tuning fork piece 2a vibrates with the second tuning fork piece 2b shown in FIG. 2, when the ab side of the second tuning fork piece 2b is compressed, the gh side of the first tuning fork piece 2a is Compress.
[0045]
Further, when the cd of the second tuning fork piece 2b is extended, the ef side of the first tuning fork piece 2a is extended.
[0046]
By these compression and expansion, positive charges are generated on the detection electrodes 14a and 14b for monitoring, and negative charges are generated on the common electrode 18. Therefore, in the first tuning fork piece 2a, when the ef side is compressed and the gh side is expanded, negative charges are generated in the monitor detection electrodes 14a and 14b, and positive charges are generated in the common electrode 18.
[0047]
FIG. 4 is a block diagram in which the angular velocity sensor of the present invention and its drive and detection circuit are connected. In FIG. 4, reference numeral 20 denotes a differential input type charge amplifier. The differential input type charge amplifier 20 is for amplifying signals obtained from the detection electrodes 16a and 17a provided on the first and second bending vibration pieces 6 and 7, respectively, and shifting the signal by 90 °. is there. Reference numeral 21 denotes a detection circuit. The detection circuit 21 detects the output signal of the charge amplifier 20 synchronously. Reference numeral 22 denotes a low-pass filter as a smoothing circuit for smoothing the detection signal obtained by the detection circuit 21. Reference numeral 23 denotes a sum input type drive circuit for driving the second and fourth tuning fork pieces 2b and 3b. By inputting signals obtained from the detection electrodes 14a, 14b, 15a, and 15b for monitoring to the drive circuit 23, the first, second, third, and fourth tuning fork vibrating pieces 2a, 2b, 3a, and 3b are targeted. The feedback control is performed so that the vibration amplitude is 15 μm. FIG. 5 shows that the first and third tuning fork pieces 2a and 3a are driven and deformed in the X-axis direction, and the second and fourth tuning fork pieces 2b and 3b are driven and deformed in the direction opposite to the X-axis direction. An example of deformation of the first, second, third, and fourth tuning fork pieces 2a, 2b, 3a, 3b, and the first and second bending vibration pieces 6 and 7 when the angular velocity around the axis is applied It is a schematic diagram for demonstrating.
[0048]
As shown in FIG. 5, by applying an angular velocity around the Z-axis, the first and third additional masses 4a and 5a are in the Y-axis direction, and the second and fourth additional masses 4b and 5b are The Coriolis force is concentrated in the direction opposite to the Y-axis direction, and this Coriolis force breaks the symmetry of the vibration amplitude of the first, second, third, and fourth tuning fork pieces 2a, 2b, 3a, 3b. It exhibits a deformation of the first-order mode. The first bending vibration piece 6 is in the X-axis direction so as to correct the stress state of the first, second, third, and fourth tuning fork pieces 2a, 2b, 3a, and 3b whose symmetry has been lost and to maintain the balance. The second bending vibration piece 7 is deformed in the X-axis direction. Since these deformations correspond to the magnitude of the applied angular velocity, they correspond to the magnitude of the applied angular velocity by the detection electrodes 16a and 17a provided on the first and second bending vibration pieces 6 and 7, respectively. It is detected as a charge amount. Since the first, second, third, and fourth additional masses 4a, 4b, 5a, and 5b are provided, the amount of deformation of the first and second tuning fork portions is increased even for a small angular velocity input. In addition, the deformation efficiency of the first and second bending vibration pieces 6 and 7 provided with the fifth and sixth additional masses 8 and 9 is improved. With these configurations, the detection signal can be further enhanced in sensitivity, and at the same time, the first and second tuning fork portions and the first and second bending vibrations can be adjusted by adjusting the additional masses 4a, 4b, 5a, 5b, 8, and 9. Adjustment of each resonance frequency of the part is also facilitated.
[0049]
FIG. 6 is a cross-sectional view of the first flexural vibration piece 6 provided with the detection electrode 16a between the first and second tuning fork pieces 2a and 2b, taken along the XZ plane. In FIG. 6, the arrow pointing in the X-axis direction indicates the electric axis of the first bending vibration piece 6 made of quartz, and 16b is the first bending vibration piece so as to face the detection electrode 16a with the bending vibration piece 6 interposed therebetween. 6 is a detection electrode provided on the XY plane (back side). Reference numeral 18 denotes a pair of common electrodes provided on the YZ plane (side surface) of the first bending vibration piece 6 so as to face each other with the first bending vibration piece 6 interposed therebetween.
[0050]
Similarly, a detection electrode 17b is provided on the second bending vibration piece 7 between the third and fourth tuning fork pieces 3a and 3b so as to face the detection electrode 17a with the second bending vibration piece 7 interposed therebetween. On the YZ plane (side surface), a pair of common electrodes 18 are provided so as to face each other with the second bending vibration piece 7 interposed therebetween.
[0051]
Next, when the first and second bending vibration pieces 6 and 7 are deformed as shown in FIG. 5, the generation state of electric charges appearing on the detection electrodes 16 a, 16 b, 17 a and 17 b and the common electrode 18 is simply described. explain.
[0052]
Since the ij side of the first bending vibration piece 6 between the first and second tuning fork pieces 2a and 2b is compressed and the kl side is extended, negative charges are generated in the detection electrodes 16a and 16b, and the common A positive charge is generated on the electrode 18. In addition, since the ij side of the second bending vibration piece 7 between the third and fourth tuning fork pieces 3a and 3b is expanded and the kl side is compressed, positive charges are generated in the detection electrodes 17a and 17b. Negative charges are generated in the common electrode 18.
[0053]
The charge obtained from the detection electrodes 16a and 16b and the charge obtained from the detection electrodes 17a and 17b are differentially amplified by the charge amplifier 20, whereby a double output is obtained. As described above, the configuration of the present embodiment enables not only a reduction in thickness without forming a high-precision comb-teeth structure electrode for driving and detection, but also provides an additional mass, so that a small angular velocity input can be achieved. On the other hand, the amount of deformation of the tuning fork portion increases, and the amount of deformation of the flexural vibration portion also increases correspondingly, so that the detection signal can be further increased in sensitivity. In addition, there is an effect of eliminating the influence of the charge and temperature generated by unnecessary components (acceleration applied from each direction) other than the angular velocity.
[0054]
In the present embodiment, the primary mode resonance frequency of the first, second, third and fourth tuning fork pieces 2a, 2b, 3a and 3b and the primary of the first and second bending vibration pieces 6 and 7 are used. By making the mode resonance frequencies close to each other, the detection sensitivity is increased.
[0055]
In the present embodiment, since the slit portions 11a, 11b, 11c, and 11d are provided in the base portion 1, disturbance vibration is mixed into the first-order bending vibrations of the first and second bending vibration pieces 6 and 7. This has the effect of preventing The first and second bending vibration pieces 6 and 7 also have a function of preventing the first-order bending vibration from leaking to the base 1.
[0056]
In the present embodiment, the base 1, first, second, third and fourth tuning fork pieces 2a, 2b, 3a and 3b, first, second, third, fourth, fifth and sixth The example in which the additional masses 4a, 4b, 5a, 5b, 8, 9 and the first and second bending vibration pieces 6 and 7 are integrally formed from a single quartz plate has been described. Any single crystal material or polycrystalline material may be used.
[0057]
In the present embodiment, the configuration in which the additional mass is provided outward from each tip of the first, second, third, and fourth tuning fork pieces 2a, 2b, 3a, 3b has been described. In the configuration in which the additional mass is provided inward or in the first and second tuning fork pieces 2a and 2b, the additional mass is outward, and in the third and fourth tuning fork pieces 3a and 3b, the additional mass is inward. Various configurations such as provision are possible.
[0058]
In the present embodiment, the first, second, third, and fourth tuning fork pieces 2a, 2b, 3a, and 3b and the first and second bending vibration pieces 6 and 7 are all attached to the tips. The configuration provided with the additional mass has been described, but there are various configurations such as a configuration in which no additional mass is provided in either the tuning fork piece or the bending vibration piece, or an addition mass is provided only in either the tuning fork piece or the bending vibration piece. Is possible.
[0059]
Further, in the present embodiment, a pair of tuning fork pieces are provided on the first and second tuning fork parts, and bending vibration is formed by one bending vibration piece between each of the first and second tuning fork parts. Although the structure provided with the portion has been described, a structure in which a pair or a plurality of pairs of tuning fork pieces and one or a plurality of bending vibration pieces are appropriately combined is naturally possible.
[0060]
(Embodiment 2)
FIG. 7 is a plan view for explaining a second embodiment of the angular velocity sensor of the present invention. In FIG. 7, the same components as those in FIG. In FIG. 7, a base 30, first, second, third and fourth tuning fork pieces 31a, 31b, 32a and 32b, first, second, third and fourth additional masses 33a, 33b, 34a and 34b. The first and second bending vibration pieces 35 and 36 and the fifth and sixth additional masses 37 and 38 are the same as those described in the first embodiment except that they are integrally formed of a constant elastic metal. The shape and dimensions shown in FIG.
[0061]
Piezoelectric ceramics 39 and 40 for driving in the primary mode are joined to the XY surfaces of the second and fourth tuning fork pieces 31b and 32b. Piezoelectric ceramics 41 and 42 for monitoring are joined on the XY surfaces of the first and third tuning fork pieces 31a and 32a. Piezoelectric ceramics 43 and 44 for detecting a charge amount corresponding to the magnitude of the angular velocity are joined on the XY plane (surface side) of the first and second bending vibration pieces 35 and 36.
[0062]
In FIG. 7, the first, second, third, and fourth tuning fork pieces 31a, 31b, 32a, and 32b, the deformation forms of the first and second bending vibration pieces 35 and 36, the piezoelectric ceramics 41 during monitoring, The tendency of the charge generated in the piezoelectric ceramics 43 and 44 when the charge generated in 42 and the angular velocity around the Z-axis are applied is the same as in the first embodiment.
[0063]
In the present embodiment, the base 30, first, second, third and fourth tuning fork pieces 31a, 31b, 32a and 32b, first, second, third, fourth, fifth and sixth The material constituting the additional masses 33a, 33b, 34a, 34b, 37, 38 and the first and second bending vibration pieces 35, 36 and the piezoelectric ceramics 39, 40, 41, 42, 43, 44 are separate materials. Since it is configured, it is possible to freely combine a material having a high Q as a mechanical vibration characteristic and a piezoelectric material having a large piezoelectric constant.
[0064]
In this embodiment, an example in which piezoelectric ceramics are joined for driving, monitoring, and detection of the amount of charge corresponding to the magnitude of the printed angular velocity has been described. It is also possible to adopt the thin film configuration.
[0065]
(Embodiment 3)
FIG. 8 is a plan view for explaining a third embodiment of the angular velocity sensor of the present invention. In FIG. 8, the drive direction is the X-axis direction, the direction in which the Coriolis force is generated is the Y-axis, and the input axis of the angular velocity Ω is the Z-axis.
[0066]
In FIG. 8, 50 is a base made of a piezoelectric ceramic having a thickness (Z-axis direction) of 0.5 mm, a length (Y-axis direction) of 15 mm, and a width (X-axis direction) of 15 mm, and 51 is the base 50 to the Y-axis direction. A vibrating piece made of piezoelectric ceramics having a thickness (Z-axis direction) of 0.5 mm extending in the opposite direction, a length of 15 mm in the Y-axis direction, and a width (X-axis direction) of 3.5 mm, 52 is a vibrating piece 51 is an additional mass portion made of piezoelectric ceramics having a thickness (Z-axis direction) of 0.5 mm, a length of 5 mm, and a width (Y-axis direction) of 3.5 mm extending from the tip of 51 in the direction opposite to the X-axis direction. . On the XY plane (surface side) of the vibrating piece 51, electrodes 53a and 54a are provided at both ends in the width direction for constituting driving means and detecting means, respectively.
[0067]
FIG. 9 is a cross-sectional view of the resonator element 51 provided with the electrodes 53a and 54a cut along the XZ plane. In FIG. 9, the arrow pointing in the Z-axis direction indicates the polarization direction of the resonator element 51 made of piezoelectric ceramics, and 53 b and 54 b indicate the XY plane of the resonator element 51 so as to face the electrodes 53 a and 54 a with the resonator element 51 interposed therebetween. It is a common electrode provided on the upper side (back side). Reference numeral 55 denotes an output signal source of the drive circuit.
[0068]
Next, the driving principle of the resonator element 51 will be briefly described. If positive and negative voltages are respectively applied from the output signal source 55 to the electrodes 53a and 54a, the side of the resonator element 51 on which the electrodes 53a and 53b are provided extends in the Y-axis direction. The side provided with 54b is compressed in the Y-axis direction. When negative and positive voltages are respectively applied to the electrodes 53a and 54a, the side of the vibrating piece 51 on which the electrodes 53a and 53b are provided is compressed in the Y-axis direction, and the electrodes 54a and 54b are provided. The extending side extends in the Y-axis direction.
[0069]
By repeating these continuously, the resonator element 51 vibrates in the primary mode in the XY plane.
[0070]
FIG. 10 is a block diagram in which the angular velocity sensor of the present invention and its drive and detection circuit are connected. FIG. 11 is a diagram for explaining an example of a deformation form of the vibrating piece 51 when an angular velocity around the Z axis as shown in FIG. 10 is applied when the vibrating piece 51 is driven and deformed in the X-axis direction. It is a schematic diagram. FIG. 12 is an explanatory diagram of voltage change states at points A and B when an angular velocity around the Z axis as shown in FIG. 10 is applied when the resonator element 51 is driven and deformed in the X axis direction. It is. In FIG. 11 and FIG. 12, a solid line indicates a case where no angular velocity is applied, and a broken line indicates a case where an angular velocity is applied. In FIG. 10, 56 is a self-oscillation drive circuit, 57 and 58 are resistors, and 59 is a summing amplifier as a detection circuit. By supplying a reverse phase voltage from the self-excited oscillation type driving circuit 56 to the electrodes 53a and 54a via the resistors 57 and 58, continuous vibration is generated as described above. As shown in FIG. 11, when positive and negative voltages are applied to the electrodes 53 a and 54 a of the vibrating piece 51 to vibrate the vibrating piece 51, an angular velocity around the Z axis as shown in FIG. 10 is applied. Then, the Coriolis force acts on the additional mass portion 52 in a direction opposite to the Y-axis direction, the side on which the electrodes 53a and 53b of the vibrating piece 51 are provided is extended in the Y-axis direction, and the electrodes 54a and 54b This is a deformation that compresses the provided side in the Y-axis direction. By such deformation, the Z-axis direction side of the vibrating piece 51 provided with the electrodes 53a and 53b is further compressed and the impedance is increased. On the contrary, the Z-axis direction side of the vibrating piece 51 provided with the electrodes 54a and 54b is further expanded and impedance is lowered. FIG. 12 shows how these changes are captured as changes in the voltages at points A and B shown in FIG.
[0071]
The final output corresponding to the magnitude of the applied angular velocity is obtained by applying the voltages at the points A and B to the summing amplifier 59.
[0072]
According to this embodiment, it is possible to reduce the thickness and increase the sensitivity without forming a high-precision comb-teeth structure electrode for driving and detecting, and also due to the application of angular velocity to the driving voltage for driving the resonator element. Detection is possible with the detection signal superimposed.
[0073]
In the present embodiment, an example using one vibrating piece and an additional mass provided at the tip of the vibrating piece has been described, but it is naturally possible to make a tuning fork configuration by pairing such structures. . As a result, when an angular velocity is applied, Coriolis forces in opposite directions act on both additional mass portions, and a double output signal can be obtained. Furthermore, it is also possible to make an H-type configuration by using two pairs of tuning fork configurations. As a result, a further increase in output signal can be expected. Further, as already described in the first embodiment, a configuration in which a bending vibration piece is provided between tuning fork parts (however, in a narrow sense that both the first and second tuning fork parts must be provided). It is also possible to use various configurations such as a configuration in which the presence or absence of additional mass and the direction in which the additional mass is formed are taken into consideration.
[0074]
(Embodiment 4)
FIG. 13 is a perspective view for explaining a fourth embodiment of the angular velocity sensor of the present invention. FIG. 14 is a schematic line for explaining an example of a deformation form of the vibration piece when an angular velocity around the Z axis as shown in FIG. 13 is applied when the vibration piece is driven and deformed in the XY plane. FIG. In FIG. 13, the driving direction is the X-axis direction, the direction in which the Coriolis force is generated is the Y-axis, and the input axis for the angular velocity Ω is the Z-axis. In FIG. 14, a solid line indicates a case where no angular velocity is applied, and a broken line indicates a case where an angular velocity is applied. In this embodiment, the basic technical idea is the same as that of the third embodiment in that detection is possible in a state where a detection signal resulting from application of angular velocity is superimposed on a driving voltage for driving the resonator element. Only different parts will be described in detail. In FIG. 13, reference numeral 60 denotes a vibrating piece formed of piezoelectric ceramics extending in the Y-axis direction, and 61 and 62 respectively extend in opposite directions to the X-axis direction and in the X-axis direction from both ends of the vibrating piece 60. First and second additional mass portions 63a and 63b formed of piezoelectric ceramics are provided on one XY surface of the vibrating piece 60 and the first additional mass portion 61 in order to support the vibrating piece 60 on the Y axis. The first and second support points 63c and 63d provided near the second and second additional mass portions 62 respectively oppose the first and second support points 63a and 63b with the vibration piece 60 interposed therebetween. Thus, the third and fourth support points 64a and 64b provided on the other XY plane of the vibrating piece 60 are both ends in the width direction (X-axis direction) of the XY plane (surface side) of the vibrating piece 60 and the second 1 additional mass portion 61 and first support point 6 First and second electrodes 65a and 65b as driving and detecting means provided between a and a are both ends in the width direction (X-axis direction) of the XY surface (front surface side) of the resonator element 60 and the second electrode The third and fourth electrodes serving as driving and detecting means provided between the additional mass portion 62 and the second supporting point 63b, 66 are fixed portions, 67a, 67b, 67c and 67d are first, Second, third, and fourth support portions. Straight lines connecting the first and third support points 63a and 63c are on the Z-axis, and the first and third support points 63a and 63c are first and third in the Z-axis direction and the direction opposite to the Z-axis direction, respectively. Third support portions 67a and 67c extend, and ends of the first and third support portions 67a and 67c are fixed to a fixing portion 66, respectively. Straight lines connecting the second and fourth support points 63b and 63d are on the Z-axis and are second and fourth from the second and fourth support points 63b and 63d in the Z-axis direction and the direction opposite to the Z-axis direction, respectively. Fourth support portions 67b and 67d extend, and ends of the second and fourth support portions 67b and 67d are fixed to the fixing portion 66, respectively.
[0075]
A common electrode is provided on the XY surface (back side) of the vibrating piece 60 so as to face the first, second, third, and fourth electrodes 64a, 64b, 65a, 65b with the vibrating piece 60 interposed therebetween. The first and third electrodes 64a and 65a have the same phase, the second and fourth electrodes 64b and 65b have the same phase, and the first and second electrodes 64a and 64b have the opposite phase, and the third and fourth phases. By supplying voltages so that the electrodes 65a and 65b are in opposite phases to each other, the first and second support points 63a and 63b are used as nodes of vibration, and bending vibrations in the primary mode continuous in the XY plane are generated. It occurs in the vibration piece 60. As shown in FIG. 14, for example, a positive voltage is applied to each of the second and fourth electrodes 64b and 65b of the resonator element 60, and a negative voltage is applied to each of the first and third electrodes 64a and 65a. When an angular velocity around the Z-axis as shown in FIG. 13 is applied when the vibrating piece 60 is vibrated, a Coriolis force acts intensively in the Y-axis direction on the first additional mass portion 61, This is a deformation in which the side on which the second electrode 64b of the vibrating piece 60 is provided is extended in the Y-axis direction and the side on which the first electrode 64a is provided is compressed in the Y-axis direction. Further, the Coriolis force acts on the second additional mass portion 62 in a direction opposite to the Y-axis direction, and the side on which the fourth electrode 65b of the resonator element 60 is provided is somewhat compressed in the Y-axis direction. The third electrode 65a side is somewhat deformed in the Y-axis direction. Due to such deformation, the Z-axis direction side of the vibrating piece 60 provided with the second and third electrodes 64b and 65a is compressed to increase the impedance. Conversely, the Z axis direction side of the resonator element 60 on which the first and fourth electrodes 64a and 65b are provided is extended to lower the impedance. By detecting these changes, a final output corresponding to the magnitude of the applied angular velocity can be obtained. This configuration not only makes it possible to reduce the thickness and increase the sensitivity without forming a high-precision comb-teeth structure electrode for driving and detection, but also a detection signal resulting from the application of angular velocity to the driving voltage for driving the resonator element. It becomes possible to detect in a state of overlapping.
[0076]
In the present embodiment, the case has been described in which the size of the vibrating piece 60 in the Z-axis direction is smaller than the size in the X-axis direction, but a configuration opposite to this is naturally possible.
[0077]
Further, in the present embodiment, the example in which the vibrating piece 60 and the first and second additional mass portions 61 and 62 are formed from an integral piezoelectric ceramic has been described. The vibrating piece and the first and second additional mass portions are integrally formed of an elastic metal material, an oxide material, or a highly elastic polymer material, and piezoelectric ceramics are bonded on the vibrating piece or exhibit piezoelectricity. Naturally, the technical idea of the present invention can be achieved even in a configuration in which various thin films are formed on the surface.
[0078]
【The invention's effect】
As described above, the present invention includes a base portion provided in the XY plane, and a first tuning fork portion including at least a pair of tuning fork pieces extending in the direction opposite to the Y-axis direction from the base portion in the XY plane, A second tuning fork portion composed of at least a pair of tuning fork pieces extending in the Y-axis direction from the base portion so as to face the first tuning fork portion, and a tuning fork that forms a pair constituting the first tuning fork portion A pair constituting the second tuning fork and a first bending vibration part composed of at least one bending vibration piece located between the pieces and extending from the base in a direction opposite to the Y-axis direction. A second bending vibration portion comprising at least one bending vibration piece extending in the Y-axis direction from the base so as to be between the tuning fork pieces and facing the first bending vibration portion; The tuning fork pieces constituting the first and second tuning fork parts are defined as the X-axis direction or the X-axis direction. When the driving means provided in the tuning fork piece to bend and vibrate in the direction of the pair and the angular velocity around the Z axis are applied, the magnitude of the Coriolis force acting in the Y axis direction or the direction opposite to the Y axis direction is increased. Provided in the bending vibration piece for detecting the deformation amount of the bending vibration piece that bends and deforms in the X-axis direction or the direction opposite to the X-axis direction so as to keep balance with the bending deformation of the tuning fork piece that changes accordingly. By providing the detection means, a thin and highly sensitive angular velocity sensor can be obtained without forming a highly accurate comb-teeth structure electrode for driving and detection.
[Brief description of the drawings]
FIG. 1 is a plan view for explaining an angular velocity sensor according to a first embodiment of the invention.
FIG. 2 is an explanatory view of a tuning fork piece provided with a drive electrode of the angular velocity sensor cut along an XZ plane.
FIG. 3 is an explanatory view of a tuning fork piece provided with a detection electrode for monitoring of the angular velocity sensor cut along an XZ plane.
FIG. 4 is a block diagram in which the same angular velocity sensor and its drive circuit and detection circuit are connected.
FIG. 5 is a schematic diagram of deformation forms of a tuning fork piece and a bending vibration piece when an angular velocity is applied to the angular velocity sensor.
FIG. 6 is an explanatory diagram in which a bending vibration piece provided with a detection electrode of the same angular velocity sensor is cut along an XZ plane.
FIG. 7 is a plan view for explaining an angular velocity sensor according to a second embodiment of the invention.
FIG. 8 is a plan view for explaining an angular velocity sensor according to a third embodiment of the present invention.
FIG. 9 is an explanatory diagram in which a vibrating piece provided with electrodes of the angular velocity sensor is cut along an XZ plane.
FIG. 10 is a block diagram in which the same angular velocity sensor and its drive circuit and detection circuit are connected.
FIG. 11 is a schematic diagram of a deformed form of the resonator element when an angular velocity is applied to the angular velocity sensor.
FIG. 12 is an explanatory diagram of a change state of voltage at points A and B when an angular velocity is applied to the angular velocity sensor.
FIG. 13 is a perspective view for explaining an angular velocity sensor according to a fourth embodiment of the present invention.
FIG. 14 is a schematic diagram of a deformed form of the resonator element when an angular velocity is applied to the angular velocity sensor.
[Explanation of symbols]
1,30,50 base
2a, 31a First tuning fork piece
2b, 31b Second tuning fork piece
3a, 32a Third tuning fork piece
3b, 32b Fourth tuning fork piece
4a, 33a First additional mass
4b, 33b Second additional mass
5a, 34a Third additional mass
5b, 34b Fourth additional mass
6,35 first bending vibration piece
7, 36 2nd bending vibration piece
8,37 Fifth additional mass
9,38 Sixth additional mass
10a, 10b, 10c, 10d hole
11a, 11b, 11c, 11d Slit part
12a, 12b, 13a, 13b Driving electrode
14a, 14b, 15a, 15b Detection electrodes for monitoring
16a, 16b, 17a, 17b Detection electrodes for angular velocity detection
18, 53b, 54b Common electrode
19, 55 Output signal source of drive circuit
20 Charge amplifier
21 Detection circuit
22 Low-pass filter
23 Drive circuit
39, 40, 41, 42, 43, 44 Piezoelectric ceramics
51, 60 Vibrating piece
52 Additional mass
53a, 54a electrode
56 Self-excited oscillation drive circuit
57,58 resistance
59 Detection circuit
61 1st additional mass part
62 2nd additional mass part
63a first support point
63b second support point
63c Third support point
63d Fourth support point
64a first electrode
64b second electrode
65a third electrode
65b fourth electrode
66 Fixed part
67a 1st support part
67b 2nd support part
67c 3rd support part
67d 4th support part

Claims

Relative to the first tuning fork, a base provided in the XY plane, a first tuning fork composed of at least a pair of tuning forks extending in the direction opposite to the Y-axis direction from the base in the XY plane, and The second tuning fork piece made of at least a pair of tuning fork pieces extending in the Y-axis direction from the base portion so as to face the tuning fork pieces constituting the first tuning fork piece and the base portion Between the first bending vibration part made up of at least one bending vibration piece extending in the direction opposite to the Y-axis direction from the first tuning vibration fork piece forming the second tuning fork part, and A second flexural vibration part comprising at least one flexural vibration piece extending in the Y-axis direction from the base so as to face the first flexural vibration part; and the first and second tuning fork parts The tuning fork piece that constitutes the bending vibration in the X-axis direction or the opposite direction Therefore, when the driving means provided in the tuning fork piece and the angular velocity around the Z axis are applied, the tuning fork that changes according to the magnitude of the Coriolis force acting in the Y axis direction or the direction opposite to the Y axis direction. Detecting means provided on the bending vibration piece for detecting the deformation amount of the bending vibration piece that is bent and deformed in the X-axis direction or in a direction opposite to the X-axis direction so as to keep a balance with the bending deformation of the piece. Angular velocity sensor.

The first and second tuning fork pieces constituting the first and second tuning fork parts are either in the X-axis direction or in the direction opposite to the X-axis direction from each tip of the pair of tuning fork pieces, The first additional mass part is formed so that the tuning fork pieces on both sides centering on each symmetry axis of the tuning fork part are opposite to each other and extend in the same direction on the same side, Each one of the bending vibration pieces constituting the first and second bending vibration parts is on the axis of symmetry of the tuning fork part and extends in the X-axis direction and the direction opposite to the X-axis direction from the tip of each bending vibration piece. The angular velocity sensor according to claim 1, wherein the second additional mass portion is formed so as to project.

The angular velocity sensor according to claim 1 or 2, wherein the resonance frequencies of the first and second tuning fork portions and the resonance frequencies of the first and second bending vibration portions are close to each other.

The angular velocity sensor according to claim 1 or 2, wherein a processing circuit for differentially detecting each detection signal detected by the detection means provided in the first and second bending vibration units is connected to the detection means. .

2. The angular velocity sensor according to claim 1, wherein the base portion, the first and second tuning fork portions, and the first and second bending vibration portions provided in the XY plane are integrally formed of a piezoelectric material.

The base portion, the first and second tuning fork portions, the first and second bending vibration portions, and the first and second additional mass portions provided in the XY plane are integrally formed of a piezoelectric material. An angular velocity sensor described in 1.

The base portion, the first and second tuning fork portions, and the first and second bending vibration portions provided in the XY plane are formed of a constant elastic metal material, an oxide material, or a high elastic polymer material, and at least the first The angular velocity sensor according to claim 1, wherein a layer made of a piezoelectric material is provided on the XY plane of the first and second tuning fork portions and the first and second bending vibration portions.

The base portion, the first and second tuning fork portions, the first and second bending vibration portions, and the first and second additional mass portions provided in the XY plane are made of a constant elastic metal material, an oxide material, or a high elasticity. The angular velocity according to claim 2, wherein the layer is made of a polymer material, and a layer made of a piezoelectric material is provided on at least the XY planes of the first and second tuning fork portions and the first and second bending vibration portions. Sensor.