JP6604158B2

JP6604158B2 - Vibration type angular velocity sensor

Info

Publication number: JP6604158B2
Application number: JP2015228265A
Authority: JP
Inventors: 知也城森; 隆雄岩城
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2015-11-23
Filing date: 2015-11-23
Publication date: 2019-11-13
Anticipated expiration: 2035-11-23
Also published as: JP2017096731A

Description

本発明は、振動型角速度センサに関するものである。 The present invention relates to a vibration type angular velocity sensor.

従来、特許文献１において、振動型角速度センサが提案されている。この振動型角速度センサでは、四角形状とされた駆動錘に相当する駆動質量体の内側に四角形状とされた検出錘に相当する検出質量体が配置された構造とされている。駆動質量体は、四隅において第１の支持梁を介して基板に支持されており、検出質量体は、第２の支持梁を介して駆動質量体に支持されている。駆動質量体のうちの外側面には駆動用の櫛歯電極が形成され、駆動質量体から離れた位置に該外側面と対向するように駆動モニタ用櫛歯電極が備えられている。これら駆動用の櫛歯電極および駆動モニタ用櫛歯電極とによって駆動櫛歯電極対を構成し、駆動櫛歯電極対の間に構成される容量への電圧印加によって、駆動質量体が駆動振動させられるようになっている。また、検出質量体の内側面には検出用の櫛歯電極が形成され、検出質量体から離れた位置に検出モニタ用櫛歯電極が配置されている。これら検出用の櫛歯電極と検出モニタ用櫛歯電極とによって検出櫛歯電極対を構成し、検出櫛歯電極対の間に構成される容量を利用して、角速度印加時に検出質量体が移動させられたときに、その移動量を容量変化として出力できるようになっている。 Conventionally, in Patent Document 1, a vibration type angular velocity sensor has been proposed. This vibration type angular velocity sensor has a structure in which a detection mass body corresponding to a square detection weight is arranged inside a drive mass body corresponding to a square drive weight. The driving mass body is supported by the substrate via the first support beams at the four corners, and the detection mass body is supported by the driving mass body via the second support beams. A comb electrode for driving is formed on the outer surface of the driving mass body, and a comb electrode for driving monitoring is provided at a position away from the driving mass body so as to face the outer surface. A driving comb electrode pair is constituted by the driving comb electrode and the driving monitoring comb electrode, and the driving mass body is driven to vibrate by applying a voltage to a capacitor formed between the driving comb electrode pair. It is supposed to be. Further, a comb electrode for detection is formed on the inner surface of the detection mass body, and the detection monitor comb electrode is disposed at a position away from the detection mass body. These detection comb electrodes and detection monitor comb electrodes constitute a detection comb electrode pair, and the detection mass moves when angular velocity is applied using the capacitance formed between the detection comb electrode pairs. When this is done, the amount of movement can be output as a change in capacity.

特開２０１３−１０８９２９号公報JP 2013-108929 A

振動型角速度センサでは、センサ精度を向上させるために、振幅精度が得られるようにすること、換言すれば所望の振幅で駆動振動させられるようにすることが重要である。このため、例えば、駆動錘の駆動振動の振幅をモニタし、駆動櫛歯電極対に印加する電位差を自動的にフィードバック制御するオートゲインコントロール（以下、ＡＧＣと略す）を行っている。 In the vibration type angular velocity sensor, in order to improve sensor accuracy, it is important to obtain amplitude accuracy, in other words, to drive and vibrate with a desired amplitude. For this reason, for example, the amplitude of the drive vibration of the drive weight is monitored, and auto gain control (hereinafter abbreviated as AGC) is performed to automatically feedback control the potential difference applied to the drive comb electrode pair.

しかしながら、駆動錘の駆動振動の振幅を精度良く検出するためには、検出回路の回路ビット数を増加させる必要がある。例えば、駆動振動の振幅検出を駆動櫛歯電極対の容量を電圧に変換、つまりＣ−Ｖ変換することで行う場合において、振幅３μｍに対してその１％の検出精度を持つ検出回路とする場合、振幅精度が０．０３μｍである。この場合、振幅を例えば１０倍の３０μｍにすると、振幅精度も１０倍に悪化して０．３μｍとなる。この場合においても、振幅精度を０．０３μｍにするには、検出回路のビット数を増加させて、より細かく振幅を検出できるようにすることが必要になる。 However, in order to accurately detect the amplitude of the driving vibration of the driving weight, it is necessary to increase the number of circuit bits of the detection circuit. For example, when detecting the amplitude of the drive vibration by converting the capacitance of the drive comb electrode pair into a voltage, that is, CV conversion, a detection circuit having a detection accuracy of 1% with respect to an amplitude of 3 μm is used. The amplitude accuracy is 0.03 μm. In this case, for example, when the amplitude is increased to 30 μm, which is 10 times, the amplitude accuracy is deteriorated 10 times to 0.3 μm. Even in this case, in order to make the amplitude accuracy 0.03 μm, it is necessary to increase the number of bits of the detection circuit so that the amplitude can be detected more finely.

本発明は上記点に鑑みて、より振幅精度を向上させることが可能な振動型角速度センサを提供することを目的とする。 In view of the above points, an object of the present invention is to provide a vibration type angular velocity sensor capable of further improving amplitude accuracy.

上記目的を達成するため、請求項１に記載の振動型角速度センサは、基板（１０）に対して固定された固定部（２０）と、駆動錘（３１、３２）および検出錘（３１、３２）とを有する可動部（３０）と、駆動錘を基板の平面と平行な平面上において移動可能としつつ固定部に対して支持する駆動梁（４２）、および、検出錘を基板の平面と平行な平面上において移動可能としつつ固定部に対して支持する検出梁（４１）を有する梁部（４０）と、駆動錘の駆動振動の振動量に応じて第１変化量で変化する第１容量を構成する第１容量構成部（６１、６４）と、駆動錘の駆動振動の振動量に応じて第１変化量よりも急な第２変化量で変化する第２容量を構成する第２容量構成部（６２、６６）と、駆動錘を基板の平面上における一方向に駆動振動させ、角速度の印加に伴って検出錘が基板の平面上において一方向に対する垂直方向にも振動することに基づき角速度検出を行う制御装置（７０）と、を備えている。そして、制御装置は、第１容量の変化に基づいて第１精度で駆動錘の駆動振動の振動量を検出すると共に、第２容量の変化に基づいて第１精度よりも高い第２精度で駆動錘の駆動振動における振動量が最も大きくなる振動位置を検出する。 In order to achieve the above object, the vibration type angular velocity sensor according to claim 1 includes a fixed portion (20) fixed to the substrate (10), a drive weight (31, 32), and a detection weight (31, 32). ), A drive beam (42) that supports the fixed weight while allowing the drive weight to move on a plane parallel to the plane of the substrate, and a detection weight parallel to the plane of the substrate. A beam portion (40) having a detection beam (41) that is supported on the fixed portion while being movable on a flat surface, and a first capacitance that changes with a first change amount according to the amount of drive vibration of the drive weight And a second capacitor that constitutes a second capacitor that changes with a second change amount that is steeper than the first change amount according to the amount of vibration of the drive weight of the drive weight. Drive component (62, 66) and drive weight in one direction on substrate plane Is moving, the detector weights with the application of the angular velocity is provided with a control unit (70) for performing angular velocity detection based on the fact that vibration in the direction perpendicular to the one direction in the plane of the substrate. The control device detects the vibration amount of the driving vibration of the driving weight with the first accuracy based on the change in the first capacitance, and drives with the second accuracy higher than the first accuracy based on the change in the second capacitance. The vibration position where the vibration amount in the driving vibration of the weight is the largest is detected.

このように、第１容量構成部によって、駆動振動に基づいて緩やかに変化する第１容量を構成する。この第１容量に基づいて振動位置を第１精度で検出することで、駆動振動における大まかな振動位置を確認する。また、第２容量構成部によって、駆動振動の振動量が最も大きくなる振動位置に近づくと大きく変化する第２容量を構成する。この第２容量に基づいて駆動振動における最も振動量の大きくなった振動位置を精度良く検出することで、回路ビット数を増やさなくても振動振幅の検出精度を高めることが可能となる。 In this way, the first capacitor that configures the first capacitor that gradually changes based on the drive vibration is formed by the first capacitor component. By detecting the vibration position with the first accuracy based on the first capacity, the rough vibration position in the drive vibration is confirmed. In addition, the second capacity constituting unit constitutes a second capacity that greatly changes when approaching the vibration position where the amount of vibration of the drive vibration becomes the largest. By accurately detecting the vibration position having the largest vibration amount in the drive vibration based on the second capacitance, it is possible to improve the vibration amplitude detection accuracy without increasing the number of circuit bits.

なお、上記各手段の括弧内の符号は、後述する実施形態に記載の具体的手段との対応関係の一例を示すものである。 In addition, the code | symbol in the bracket | parenthesis of each said means shows an example of a corresponding relationship with the specific means as described in embodiment mentioned later.

第１実施形態にかかる振動型角速度センサの上面レイアウト図である。It is a top surface layout figure of a vibration type angular velocity sensor concerning a 1st embodiment. 振動型角速度センサの斜視図である。It is a perspective view of a vibration type angular velocity sensor. 図１中のIII−III断面図である。It is III-III sectional drawing in FIG. 図１中のIV−IV断面図である。It is IV-IV sectional drawing in FIG. 振動型角速度センサのブロック構成例を示した図である。It is the figure which showed the block structural example of the vibration type angular velocity sensor. 振動型角速度センサにおける駆動兼検出用錘の近傍の拡大図である。It is an enlarged view of the vicinity of the weight for a drive and detection in a vibration type angular velocity sensor. 図１に示す振動型角速度センサの駆動振動時の様子を示した上面図である。It is the top view which showed the mode at the time of the drive vibration of the vibration type angular velocity sensor shown in FIG. 図１に示す振動型角速度センサの角速度印加時の様子を示した上面図である。It is the top view which showed the mode at the time of the angular velocity application of the vibration type angular velocity sensor shown in FIG. 駆動兼検出用錘の駆動振動に伴う第１容量および第２容量の変化の一例を示した図である。It is the figure which showed an example of the change of the 1st capacity | capacitance accompanying the drive vibration of the weight for a drive and detection, and a 2nd capacity | capacitance. 第２実施形態にかかる振動型角速度センサにおける駆動兼検出用錘の近傍の拡大図である。It is an enlarged view of the vicinity of the weight for a drive and detection in the vibration type angular velocity sensor concerning 2nd Embodiment. 駆動兼検出用錘の駆動振動に伴う第１容量および第２容量の変化の一例を示した図である。It is the figure which showed an example of the change of the 1st capacity | capacitance accompanying the drive vibration of the weight for a drive and detection, and a 2nd capacity | capacitance.

以下、本発明の実施形態について図に基づいて説明する。なお、以下の各実施形態相互において、互いに同一もしくは均等である部分には、同一符号を付して説明を行う。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

（第１実施形態）
本発明の第１実施形態について説明する。本実施形態で説明する振動型角速度センサ（いわゆるジャイロセンサ）は、物理量として角速度を検出するためのセンサである。振動型角速度センサは、例えば車両の上下方向に平行な中心線周りの回転角速度の検出に用いられるが、勿論、車両用以外に適用されても良い。 (First embodiment)
A first embodiment of the present invention will be described. A vibration type angular velocity sensor (a so-called gyro sensor) described in the present embodiment is a sensor for detecting an angular velocity as a physical quantity. The vibration type angular velocity sensor is used, for example, to detect a rotational angular velocity around a center line parallel to the vertical direction of the vehicle, but may be applied to other than a vehicle.

以下、図１〜図８を参照して、本実施形態にかかる振動型角速度センサについて説明する。 Hereinafter, the vibration type angular velocity sensor according to the present embodiment will be described with reference to FIGS.

振動型角速度センサのセンサ素子１００は、図１中のｘｙ平面が車両水平方向に向けられ、ｚ軸方向が車両の上下方向と一致するようにして車両に搭載される。振動型角速度センサのセンサ素子１００は、図２に示すように板状の基板１０を用いて形成されている。本実施形態では、基板１０は、支持基板１１と半導体層１２とで犠牲層となる埋込酸化膜１３を挟み込んだ構造とされたＳＯＩ（Silicon on insulatorの略）基板にて構成されている。この基板１０の平面の一方向がｘ軸、この平面上におけるｘ軸に対する垂直方向がｙ軸、この平面の法線方向かつｘ軸およびｙ軸に対する垂直方向がｚ軸となり、この基板１０の平面がｘｙ平面と平行な平面をなしている。このような基板１０を用いてセンサ素子１００が構成されており、図２に示すように、例えば半導体層１２側をセンサ構造体のパターンにエッチングしたのち埋込酸化膜１３を部分的に除去し、センサ構造体の一部をリリースすることで構成されている。なお、図２中では支持基板１１を簡略化して記載してあるが、実際には平面板状で構成されている。また、図２は断面図ではないが、図を見やすくするために、埋込酸化膜１３にハッチングを示してある。 The sensor element 100 of the vibration type angular velocity sensor is mounted on the vehicle such that the xy plane in FIG. 1 is oriented in the horizontal direction of the vehicle and the z-axis direction coincides with the vertical direction of the vehicle. The sensor element 100 of the vibration type angular velocity sensor is formed using a plate-like substrate 10 as shown in FIG. In the present embodiment, the substrate 10 is constituted by an SOI (abbreviation of silicon on insulator) substrate having a structure in which a buried oxide film 13 which is a sacrificial layer is sandwiched between a support substrate 11 and a semiconductor layer 12. One direction of the plane of the substrate 10 is the x-axis, the direction perpendicular to the x-axis on the plane is the y-axis, and the normal direction of the plane and the direction perpendicular to the x-axis and the y-axis are the z-axis. Is a plane parallel to the xy plane. The sensor element 100 is configured using such a substrate 10 and, as shown in FIG. 2, for example, the buried oxide film 13 is partially removed after the semiconductor layer 12 side is etched into the pattern of the sensor structure. It is configured by releasing a part of the sensor structure. Although the support substrate 11 is simplified in FIG. 2, it is actually configured as a flat plate. Further, although FIG. 2 is not a cross-sectional view, hatching is shown in the buried oxide film 13 for easy understanding of the drawing.

半導体層１２は、固定部２０と可動部３０および梁部４０にパターニングされている。固定部２０は、図２に示すように、少なくともその裏面の一部に埋込酸化膜１３が残されており、支持基板１１からリリースされることなく、埋込酸化膜１３を介して支持基板１１に固定された状態とされている。可動部３０および梁部４０は、センサ素子１００における振動子を構成するものである。可動部３０は、その裏面側において埋込酸化膜１３が除去されており、支持基板１１からリリースされている。梁部４０は、可動部３０を支持すると共に角速度検出を行うために可動部３０をｘ軸方向およびｙ軸方向において変位させるものである。これら固定部２０と可動部３０および梁部４０の具体的な構造を説明する。 The semiconductor layer 12 is patterned into the fixed portion 20, the movable portion 30, and the beam portion 40. As shown in FIG. 2, the fixed portion 20 has the buried oxide film 13 left at least on a part of the back surface thereof, and is not released from the support substrate 11, but is supported via the buried oxide film 13. 11 is fixed. The movable part 30 and the beam part 40 constitute a vibrator in the sensor element 100. The movable portion 30 is released from the support substrate 11 from which the buried oxide film 13 is removed on the back surface side. The beam portion 40 supports the movable portion 30 and displaces the movable portion 30 in the x-axis direction and the y-axis direction in order to detect angular velocity. Specific structures of the fixed portion 20, the movable portion 30, and the beam portion 40 will be described.

固定部２０は、可動部３０を支持すると共に、図示しないが駆動用電圧の印加用のパッドや角速度検出に用いられる検出信号の取り出し用のパッドが形成される部分である。本実施形態では、これら各機能を１つの固定部２０によって実現しているが、例えば可動部３０を支持するための支持用固定部、駆動用電圧が印加される駆動用固定部、角速度検出に用いられる検出用固定部に分割した構成とされても良い。その場合、例えば図１に示した固定部２０を支持固定部とし、支持固定部に連結されるように駆動用固定部と検出用固定部を備え、駆動用固定部に駆動用電圧の印加用のパッドを備えると共に検出用固定部に検出信号取り出し用のパッドを備えればよい。 The fixed portion 20 is a portion that supports the movable portion 30 and is formed with a pad for applying a driving voltage and a pad for taking out a detection signal used for angular velocity detection (not shown). In the present embodiment, each of these functions is realized by a single fixed unit 20, but for example, a support fixed unit for supporting the movable unit 30, a drive fixed unit to which a drive voltage is applied, and angular velocity detection. It may be configured to be divided into detection fixing parts to be used. In this case, for example, the fixing unit 20 shown in FIG. 1 is used as a support fixing unit, and a driving fixing unit and a detection fixing unit are provided so as to be connected to the supporting fixing unit, and a driving voltage is applied to the driving fixing unit. And a detection signal extraction pad may be provided in the detection fixing portion.

固定部２０は、例えば上面形状が四角形で構成されている。固定部２０の下方には埋込酸化膜１３が残されており、埋込酸化膜１３を介して固定部２０が支持基板１１に固定されている。固定部２０のｘ軸方向およびｙ軸方向の幅については任意であるが、後述する検出梁４１の幅よりも広くしてある。 For example, the fixed portion 20 has a quadrangular upper surface shape. The buried oxide film 13 is left below the fixed portion 20, and the fixed portion 20 is fixed to the support substrate 11 through the buried oxide film 13. The width of the fixed portion 20 in the x-axis direction and the y-axis direction is arbitrary, but is wider than the width of the detection beam 41 described later.

可動部３０は、角速度印加に応じて変位する部分であり、駆動用電圧の印加によって駆動振動させられる駆動用錘と駆動振動時に角速度が印加されたときにその角速度に応じて振動させられる検出用錘とを有した構成とされる。本実施形態の場合、可動部３０として、駆動用錘と検出用錘の役割を同じ錘によって担う駆動兼検出用錘３１、３２が備えられている。駆動兼検出用錘３１、３２は、ｘ軸方向において、固定部２０を挟んだ両側に配置されており、固定部２０から等間隔の場所に配置されている。各駆動兼検出用錘３１、３２は、同寸法、同質量で構成され、本実施形態の場合、上面形状が四角形で構成されている。そして、各駆動兼検出用錘３１、３２は、それぞれ相対する二辺において梁部４０に備えられる後述する駆動梁４２に連結させられることで、両持ち支持されている。各駆動兼検出用錘３１、３２の下方においては、埋込酸化膜１３が除去されており、支持基板１１から各駆動兼検出用錘３１、３２がリリースされている。このため、各駆動兼検出用錘３１、３２は、駆動梁４２の変形によってｘ軸方向に駆動振動可能とされ、角速度印加の際には駆動梁４２などの変形によってｙ軸方向を含む固定部２０を中心とした回転方向へも振動可能とされている。 The movable portion 30 is a portion that is displaced in response to the application of the angular velocity, and a detection weight that is vibrated according to the angular velocity when the angular velocity is applied during the driving vibration and a driving weight that is driven and vibrated by the application of the driving voltage. The configuration includes a weight. In the case of the present embodiment, as the movable portion 30, drive and detection weights 31, 32 that serve as a drive weight and a detection weight by the same weight are provided. The drive and detection weights 31 and 32 are disposed on both sides of the fixed portion 20 in the x-axis direction, and are disposed at equal intervals from the fixed portion 20. Each of the driving / detecting weights 31 and 32 is configured with the same size and the same mass, and in the case of the present embodiment, the upper surface shape is configured with a quadrangle. Each of the drive / detection weights 31 and 32 is supported at both ends by being connected to a drive beam 42 (described later) provided in the beam portion 40 at two opposite sides. Under the driving and detection weights 31 and 32, the buried oxide film 13 is removed, and the driving and detection weights 31 and 32 are released from the support substrate 11. For this reason, each of the driving and detecting weights 31 and 32 can be driven to vibrate in the x-axis direction by deformation of the driving beam 42, and when the angular velocity is applied, the fixed portion including the y-axis direction by deformation of the driving beam 42 and the like. It is also possible to vibrate in the direction of rotation about 20.

梁部４０は、検出梁４１と、駆動梁４２および支持部材４３を有した構成とされている。 The beam portion 40 is configured to include a detection beam 41, a drive beam 42, and a support member 43.

検出梁４１は、固定部２０と支持部材４３とを連結するｙ軸方向に延設された直線状の梁とされている。検出梁４１のｘ軸方向の寸法は、ｚ軸方向の寸法よりも薄くされており、ｘ軸方向に変形可能とされている。 The detection beam 41 is a linear beam extending in the y-axis direction that connects the fixed portion 20 and the support member 43. The dimension of the detection beam 41 in the x-axis direction is thinner than the dimension in the z-axis direction, and can be deformed in the x-axis direction.

駆動梁４２は、駆動兼検出用錘３１、３２と支持部材４３とを連結するｙ軸方向、つまり検出梁４１と平行な方向に延設された直線状の梁とされている。各駆動兼検出用錘３１、３２に接続られた駆動梁４２から検出梁４１までは等距離とされている。駆動梁４２のｘ軸方向の寸法も、ｚ軸方向の寸法よりも薄くされており、ｘ軸方向に変形可能とされている。これにより、駆動兼検出用錘３１、３２をｘｙ平面状において変位可能としている。 The drive beam 42 is a linear beam extending in the y-axis direction connecting the drive and detection weights 31 and 32 and the support member 43, that is, in a direction parallel to the detection beam 41. The drive beam 42 connected to each of the drive / detection weights 31 and 32 and the detection beam 41 are equidistant. The dimension of the drive beam 42 in the x-axis direction is also thinner than the dimension in the z-axis direction, and can be deformed in the x-axis direction. Thereby, the drive and detection weights 31 and 32 can be displaced in the xy plane.

支持部材４３は、ｘ軸方向に延設された直線状の部材とされ、支持部材４３の中心位置において検出梁４１が連結されており、両端位置において各駆動梁４２が連結されている。支持部材４３は、ｙ軸方向の寸法が検出梁４１や駆動梁４２におけるｘ軸方向の寸法よりも大きくされている。このため、駆動振動時には駆動梁４２が主に変形し、角速度印加時には検出梁４１および駆動梁４２が主に変形するようになっている。 The support member 43 is a linear member extending in the x-axis direction, and the detection beam 41 is connected at the center position of the support member 43, and the drive beams 42 are connected at both end positions. The support member 43 has a dimension in the y-axis direction larger than a dimension in the x-axis direction of the detection beam 41 and the drive beam 42. For this reason, the driving beam 42 is mainly deformed during driving vibration, and the detection beam 41 and the driving beam 42 are mainly deformed when the angular velocity is applied.

このような構造により、駆動梁４２と支持部材４３および駆動兼検出用錘３１、３２によって上面形状が四角形の枠体が構成され、その内側に検出梁４１および固定部２０が配置されたセンサ素子１００が構成されている。 With such a structure, the driving beam 42, the support member 43, and the driving and detection weights 31 and 32 form a frame having a quadrangular top shape, and the detection beam 41 and the fixing portion 20 are arranged inside thereof. 100 is configured.

さらに、駆動梁４２には、図１および図３に示すように駆動部５１が形成されており、検出梁４１には、図４に示すように、振動検出部５３が形成されている。これら駆動部５１および振動検出部５３が、図５に示すように、外部に備えられた制御装置７０に電気的に接続されている。そして、制御装置７０からの駆動信号が伝えられることでセンサ素子１００の駆動が行われると共に、センサ素子１００からの角速度の検出信号が制御装置７０に伝えられることで角速度検出が行われるようになっている。 Further, as shown in FIGS. 1 and 3, the drive unit 42 is formed on the drive beam 42, and the vibration detection unit 53 is formed on the detection beam 41 as shown in FIG. 4. As shown in FIG. 5, the drive unit 51 and the vibration detection unit 53 are electrically connected to a control device 70 provided outside. Then, the sensor element 100 is driven by transmitting the drive signal from the control device 70, and the angular velocity detection is performed by transmitting the angular velocity detection signal from the sensor element 100 to the control device 70. ing.

駆動部５１は、図１に示すように、各駆動梁４２のうち支持部材４３との連結部近傍に備えられており、各場所に２本ずつ所定距離を空けて配置され、ｙ軸方向に延設されている。図３に示すように、駆動部５１は、駆動梁４２を構成する半導体層１２の表面に下層電極５１ａと駆動用薄膜５１ｂおよび上層電極５１ｃが順に積層された構造とされている。下層電極５１ａおよび上層電極５１ｃは、例えばＡｌ電極などによって構成されている。これら下層電極５１ａおよび上層電極５１ｃは、図１に示した支持部材４３および検出梁４１を経て固定部２０まで引き出された配線部５１ｄ、５１ｅを通じて、図示しない駆動用電圧の印加用のパッドやＧＮＤ接続用のパッドに接続されている。また、駆動用薄膜５１ｂは、例えばチタン酸ジルコン酸鉛（いわゆるＰＺＴ）膜によって構成されている。 As shown in FIG. 1, the drive unit 51 is provided in the vicinity of the connection portion of each drive beam 42 to the support member 43, and two drive units 51 are arranged at a predetermined distance from each other in the y-axis direction. It is extended. As shown in FIG. 3, the driving unit 51 has a structure in which a lower layer electrode 51a, a driving thin film 51b, and an upper layer electrode 51c are sequentially stacked on the surface of the semiconductor layer 12 constituting the driving beam. The lower layer electrode 51a and the upper layer electrode 51c are composed of, for example, an Al electrode. The lower layer electrode 51a and the upper layer electrode 51c are connected to a pad or GND for applying a driving voltage (not shown) through the wiring members 51d and 51e drawn out to the fixing unit 20 through the support member 43 and the detection beam 41 shown in FIG. It is connected to the pad for connection. The driving thin film 51b is made of, for example, a lead zirconate titanate (so-called PZT) film.

このような構成において、下層電極５１ａと上層電極５１ｃとの間に電位差を発生させることで、これらの間に挟まれた駆動用薄膜５１ｂを変位させ、駆動梁４２を強制振動させることで駆動兼検出用錘３１、３２をｘ軸方向に沿って駆動振動させる。例えば、各駆動梁４２のｘ軸方向の両端側に１本ずつ駆動部５１を備えるようにし、一方の駆動部５１の駆動用薄膜５１ｂを圧縮応力で変位させると共に他方の駆動部５１の駆動用薄膜５１ｂを引張応力で変位させる。このような電圧印加を各駆動部５１に対して交互に繰り返し行うことで、駆動兼検出用錘３１、３２をｘ軸方向に沿って駆動振動させている。 In such a configuration, by generating a potential difference between the lower layer electrode 51a and the upper layer electrode 51c, the driving thin film 51b sandwiched therebetween is displaced, and the driving beam 42 is forcibly vibrated, thereby driving and driving. The detection weights 31 and 32 are driven to vibrate along the x-axis direction. For example, one drive unit 51 is provided at each end in the x-axis direction of each drive beam 42, and the drive thin film 51b of one drive unit 51 is displaced by a compressive stress and the other drive unit 51 is driven. The thin film 51b is displaced by tensile stress. Such voltage application is alternately and repeatedly performed on each drive unit 51, thereby driving and detecting weights 31 and 32 to be driven to vibrate along the x-axis direction.

振動検出部５３は、図１および図４に示すように、検出梁４１のうちの固定部２０との連結部近傍に備えられており、検出梁４１におけるｘ軸方向の両側それぞれに設けられ、ｙ軸方向に延設されている。図４に示すように、振動検出部５３は、検出梁４１を構成する半導体層１２の表面に下層電極５３ａと検出用薄膜５３ｂおよび上層電極５３ｃが順に積層された構造とされている。下層電極５３ａおよび上層電極５３ｃや検出用薄膜５３ｂは、それぞれ、振動検出部５３を構成する下層電極５１ａおよび上層電極５１ｃや駆動用薄膜５１ｂと同様の構成とされている。下層電極５３ａおよび上層電極５３ｃは、図１に示した固定部２０まで引き出された配線部５３ｄ、５３ｅを通じて、図示しない検出信号出力用のパッドに接続されている。 As shown in FIG. 1 and FIG. 4, the vibration detection unit 53 is provided in the vicinity of the connection portion of the detection beam 41 with the fixed unit 20 and is provided on each side of the detection beam 41 in the x-axis direction. It extends in the y-axis direction. As shown in FIG. 4, the vibration detection unit 53 has a structure in which a lower layer electrode 53a, a detection thin film 53b, and an upper layer electrode 53c are sequentially stacked on the surface of the semiconductor layer 12 constituting the detection beam 41. The lower layer electrode 53a, the upper layer electrode 53c, and the detection thin film 53b have the same configuration as the lower layer electrode 51a, the upper layer electrode 51c, and the driving thin film 51b that constitute the vibration detection unit 53, respectively. The lower layer electrode 53a and the upper layer electrode 53c are connected to a detection signal output pad (not shown) through the wiring portions 53d and 53e drawn to the fixing portion 20 shown in FIG.

このような構成では、角速度の印加に伴って検出梁４１が変位すると、それに伴って検出用薄膜５３ｂが変形する。これにより、例えば下層電極５３ａと上層電極５３ｃとの間の電気信号（すなわち、定電圧駆動の場合の電流値、定電流駆動の場合の電流値）が変化する。このため、その電気信号を角速度を示す検出信号として図示しない検出信号出力用のパッドを通じて外部の制御装置７０に出力している。 In such a configuration, when the detection beam 41 is displaced as the angular velocity is applied, the detection thin film 53b is deformed accordingly. Thereby, for example, an electrical signal between the lower layer electrode 53a and the upper layer electrode 53c (that is, a current value in the case of constant voltage driving and a current value in the case of constant current driving) changes. Therefore, the electrical signal is output as a detection signal indicating the angular velocity to the external control device 70 through a detection signal output pad (not shown).

また、駆動兼検出用錘３１、３２およびその周囲には、図６に示したように駆動振動検出部６０が備えられている。この駆動振動検出部６０の詳細構造について説明する。なお、図６では、駆動兼検出用錘３２およびその周囲に備えられる駆動振動検出部６０を示しているが、駆動兼検出用錘３１およびその周囲にも同様の構造のものが備えられている。 Further, as shown in FIG. 6, a driving vibration detecting unit 60 is provided around the driving and detecting weights 31 and 32 and the periphery thereof. The detailed structure of the drive vibration detector 60 will be described. 6 shows the drive / detection weight 32 and the drive vibration detection unit 60 provided around the drive / detection weight 32, the drive / detection weight 31 and the periphery thereof have the same structure. .

図６に示すように、駆動兼検出用錘３２は、四角形で構成されており、ｘ軸と平行な相対する二辺において駆動梁４２に連結されている。そして、駆動兼検出用錘３２のうち駆動梁４２と連結されている２辺と異なる相対するｙ軸と平行な２辺において、ｘ軸方向に沿って複数の可動櫛歯電極６１が形成されている。可動櫛歯電極６１は、駆動兼検出用錘３２におけるｙ軸方向の両側に離れて複数個ずつ備えられており、ここではそれぞれ同数ずつとされている。また、可動櫛歯電極６１が離されることで空いている部分において、駆動兼検出用錘３２の側面、つまり駆動振動の方向を法線方向とする一面に可動平面電極６２が形成されている。 As shown in FIG. 6, the drive / detection weight 32 has a quadrangular shape and is connected to the drive beam 42 at two opposite sides parallel to the x-axis. A plurality of movable comb electrodes 61 are formed along the x-axis direction on two sides parallel to the opposite y-axis different from the two sides connected to the drive beam 42 in the driving and detecting weight 32. Yes. A plurality of movable comb electrodes 61 are provided on both sides in the y-axis direction of the driving / detecting weight 32, and here, the same number is provided. In addition, in a portion that is vacant when the movable comb electrode 61 is separated, the movable planar electrode 62 is formed on the side surface of the driving / detecting weight 32, that is, on one surface with the direction of driving vibration as the normal direction.

一方、駆動兼検出用錘３２のｙ軸と平行な辺のうち可動櫛歯電極６１が形成された部分と対向する位置には、櫛歯固定部６３が形成されている。この櫛歯固定部６３には複数の可動櫛歯電極６１と対向するｘ軸方向に伸びた固定櫛歯電極６４が形成されている。駆動兼検出用錘３２のｙ軸と平行な辺のうち可動平面電極６２が形成された部分と対向する位置には、電極固定部６５が形成されている。この電極固定部６５のうち駆動兼検出用錘３２と対向する一面には固定平面電極６６が形成されている。 On the other hand, a comb-tooth fixing portion 63 is formed at a position facing a portion where the movable comb-tooth electrode 61 is formed on the side parallel to the y-axis of the driving and detecting weight 32. The comb-teeth fixing portion 63 is formed with a fixed comb-teeth electrode 64 extending in the x-axis direction facing the plurality of movable comb-teeth electrodes 61. An electrode fixing portion 65 is formed at a position facing a portion where the movable plane electrode 62 is formed in a side parallel to the y-axis of the driving and detecting weight 32. A fixed flat electrode 66 is formed on one surface of the electrode fixing portion 65 facing the driving / detecting weight 32.

これらのうち、可動櫛歯電極６１と固定櫛歯電極６４とが、駆動兼検出用錘３２におけるｘ軸方向の振動を粗い第１精度で検出するための第１容量構成部として機能する。また、可動平面電極６２と固定平面電極６６とが、駆動兼検出用錘３２におけるｘ軸方向の振動を第１精度よりも高い第２精度で検出する第２容量構成部として機能する。 Among these, the movable comb electrode 61 and the fixed comb electrode 64 function as a first capacitance component for detecting the vibration in the x-axis direction in the drive / detection weight 32 with coarse first accuracy. In addition, the movable flat electrode 62 and the fixed flat electrode 66 function as a second capacitance component that detects vibration in the x-axis direction in the driving and detecting weight 32 with a second accuracy higher than the first accuracy.

なお、図中には記載していないが、櫛歯固定部６３や電極固定部６５は、例えば支持基板１１を通じて制御装置７０に引き出される配線部と電気的に接続されている。可動櫛歯電極６１や可動平面電極６２は駆動兼検出用錘３２に電気的に接続されており、駆動兼検出用錘３２は、駆動梁４２や支持部材４３および検出梁４１を通じて固定部２０に引き出された配線を通じて制御装置７０に電気的に接続されている。 Although not shown in the figure, the comb fixing portion 63 and the electrode fixing portion 65 are electrically connected to a wiring portion that is drawn out to the control device 70 through the support substrate 11, for example. The movable comb electrode 61 and the movable planar electrode 62 are electrically connected to the drive / detection weight 32, and the drive / detection weight 32 is connected to the fixed portion 20 through the drive beam 42, the support member 43, and the detection beam 41. The control device 70 is electrically connected through the drawn wiring.

そして、可動櫛歯電極６１と固定櫛歯電極６４との間に構成される容量を第１容量として、駆動兼検出用錘３２がｘ軸方向に振動したときに、櫛歯固定部６３を通じて第１容量の変化が制御装置７０に出力される。同様に、可動平面電極６２と固定平面電極６６との間に構成される容量を第２容量として、駆動兼検出用錘３２がｘ軸方向に振動したときに、電極固定部６５を通じて第２容量の変化が制御装置７０に出力される。すなわち、駆動兼検出用錘３２のｘ軸方向の振動に伴って、可動櫛歯電極６１と固定櫛歯電極６４との間の対向面積が変化することから、第１容量が変化する。同様に、可動平面電極６２と固定平面電極６６との間の距離が変化することから、第２容量が変化する。これら第１容量および第２容量の変化が、図５に示したようにＣ−Ｖ変換回路８０を通じて電気的な検出信号として取り出され、これが制御装置７０に出力される。 Then, when the drive / detection weight 32 vibrates in the x-axis direction with the capacitance formed between the movable comb electrode 61 and the fixed comb electrode 64 as the first capacitance, the first capacitance is passed through the comb fixing portion 63. The change of 1 capacity is output to the control device 70. Similarly, when the drive / detection weight 32 vibrates in the x-axis direction when the capacitance formed between the movable planar electrode 62 and the fixed planar electrode 66 is the second capacitance, the second capacitance is obtained through the electrode fixing portion 65. Is output to the control device 70. That is, as the drive / detection weight 32 is vibrated in the x-axis direction, the opposing area between the movable comb electrode 61 and the fixed comb electrode 64 changes, so the first capacitance changes. Similarly, since the distance between the movable plane electrode 62 and the fixed plane electrode 66 changes, the second capacitance changes. These changes in the first capacitance and the second capacitance are taken out as electrical detection signals through the CV conversion circuit 80 as shown in FIG. 5 and output to the control device 70.

このとき、第１容量については、駆動兼検出用錘３２の駆動振動に伴って、緩やかに変化することになる。これに対して、第２容量については、駆動兼検出用錘３２の駆動振動に伴って変化するものの、可動平面電極６２と固定平面電極６６との間の距離が離れているときには緩やかな変化で、近づくと急峻に変化する。これら変化の異なる第１容量および第２容量の検出信号がそれぞれＣ−Ｖ変換回路８０を介して制御装置７０に伝えられるようになっている。 At this time, the first capacitance changes gradually with the drive vibration of the drive / detection weight 32. On the other hand, the second capacitance changes with the driving vibration of the driving / detecting weight 32, but changes slowly when the distance between the movable flat electrode 62 and the fixed flat electrode 66 is large. , Changes steeply when approaching. The first and second capacitance detection signals having different changes are transmitted to the control device 70 via the CV conversion circuit 80, respectively.

以上のようにして、本実施形態にかかる振動型角速度センサが構成されている。次に、このように構成される振動型角速度センサの作動について説明する。 As described above, the vibration type angular velocity sensor according to the present embodiment is configured. Next, the operation of the vibration type angular velocity sensor configured as described above will be described.

まず、図３に示すように、駆動梁４２に備えられた駆動部５１に対して駆動用電圧の印加を行う。具体的には、下層電極５１ａと上層電極５１ｃとの間に電位差を発生させることで、これらの間に挟まれた駆動用薄膜５１ｂを変位させる。そして、２本並んで設けられた２つの駆動部５１のうち、一方の駆動部５１の駆動用薄膜５１ｂを圧縮応力で変位させると共に他方の駆動部５１の駆動用薄膜５１ｂを引張応力で変位させる。このような電圧印加を各駆動部５１に対して交互に繰り返し行うことで、駆動兼検出用錘３１、３２をｘ軸方向に沿って駆動振動させる。これにより、図７に示すように、駆動梁４２によって両持ち支持された駆動兼検出用錘３１、３２が固定部２０を挟んでｘ軸方向において互いに逆方向に移動させられる駆動モードとなる。つまり、駆動兼検出用錘３１、３２が共に固定部２０が近づく状態と遠ざかる状態とが繰り返されるモードとなる。 First, as shown in FIG. 3, a drive voltage is applied to the drive unit 51 provided in the drive beam 42. Specifically, by generating a potential difference between the lower layer electrode 51a and the upper layer electrode 51c, the driving thin film 51b sandwiched therebetween is displaced. Of the two driving units 51 provided side by side, the driving thin film 51b of one driving unit 51 is displaced by compressive stress and the driving thin film 51b of the other driving unit 51 is displaced by tensile stress. . Such voltage application is alternately and repeatedly performed on each drive unit 51, thereby driving and vibrating the weights 31 and 32 for driving and detection along the x-axis direction. As a result, as shown in FIG. 7, the driving and detection weights 31 and 32 supported at both ends by the driving beam 42 are moved in opposite directions in the x-axis direction with the fixed portion 20 interposed therebetween. That is, both the driving and detection weights 31 and 32 are in a mode in which the state where the fixed portion 20 approaches and the state where the fixing portion 20 moves away are repeated.

この駆動振動が行われているときに、振動型角速度センサに対して角速度、つまり固定部２０を中心軸としたｘ軸周りの振動が印加されると、図８に示すように駆動兼検出用錘３１、３２がｙ軸方向を含む固定部２０を中心とした回転方向へも振動する検出モードとなる。これにより、検出梁４１も変位し、この検出梁４１の変位に伴って、振動検出部５３に備えられた検出用薄膜５３ｂが変形する。これにより、例えば下層電極５３ａと上層電極５３ｃとの間の電気信号が変化し、この電気信号が外部に備えられる制御装置７０に入力されることで、発生した角速度を検出することが可能となる。 When this drive vibration is performed, if an angular velocity, that is, vibration around the x-axis with the fixed portion 20 as the central axis is applied to the vibration-type angular velocity sensor, as shown in FIG. In the detection mode, the weights 31 and 32 vibrate in the rotational direction around the fixed portion 20 including the y-axis direction. Accordingly, the detection beam 41 is also displaced, and the detection thin film 53b provided in the vibration detection unit 53 is deformed along with the displacement of the detection beam 41. Thereby, for example, the electrical signal between the lower layer electrode 53a and the upper layer electrode 53c changes, and this electrical signal is input to the control device 70 provided outside, whereby the generated angular velocity can be detected. .

また、上記のようにして駆動振動が行われるときに、駆動振動が所望の振動量で行われるように、制御装置７０にて駆動兼検出用錘３２の駆動振動の振幅をモニタし、駆動部５１に対して印加する駆動用電圧を自動的にフィードバック制御するＡＧＣを行っている。このときの駆動振動の振幅のモニタを第１容量の変化と第２容量の変化に基づいて精度良く行えるようにしている。これについて、第１容量と第２容量の変化の様子を参照して説明する。 Further, when the drive vibration is performed as described above, the control device 70 monitors the amplitude of the drive vibration of the drive / detection weight 32 so that the drive vibration is performed with a desired vibration amount, and the drive unit AGC for automatically feedback-controlling the driving voltage applied to 51 is performed. At this time, the amplitude of the drive vibration can be monitored accurately based on the change in the first capacitance and the change in the second capacitance. This will be described with reference to changes in the first capacitance and the second capacitance.

図９は、駆動兼検出用錘３２の駆動振動に伴う第１容量および第２容量の変化の一例を示している。図９に示されるように、第１容量は、サイン波状の変化を示し、駆動兼検出用錘３２の駆動振動に伴って緩やかな変化となる。これに対して、第２容量については、可動平面電極６２と固定平面電極６６との間の距離が離れているときには殆ど変化せず、近づくと急峻に変化している。 FIG. 9 shows an example of changes in the first capacitance and the second capacitance accompanying the drive vibration of the drive / detection weight 32. As shown in FIG. 9, the first capacitor exhibits a sine wave-like change, and changes gradually with the drive vibration of the drive / detection weight 32. On the other hand, the second capacitance hardly changes when the distance between the movable flat electrode 62 and the fixed flat electrode 66 is long, and changes sharply when approaching.

このような現象を利用して、駆動兼検出用錘３２の駆動振動の粗動検出、つまりｘ軸方向における振動位置の大まかな検出を行うと共に、駆動振動の微動検出、つまりｘ軸方向における振動位置の細かな検出を行う。すなわち、Ｃ−Ｖ変換回路８０において、第１容量および第２容量をそれぞれ電圧変換し、これらを第１容量および第２容量を示す検出信号として制御装置７０に入力する。そして、制御装置７０にて、第１容量を示す検出信号に基づいて駆動兼検出用錘３２の駆動振動の粗動検出を行い、第２容量を示す検出信号に基づいて駆動兼検出用錘３２の駆動振動の微動検出を行う。 By utilizing such a phenomenon, coarse movement detection of the driving vibration of the driving / detecting weight 32, that is, rough detection of the vibration position in the x-axis direction, and fine detection of driving vibration, that is, vibration in the x-axis direction are performed. Detailed position detection is performed. That is, in the CV conversion circuit 80, the first capacitor and the second capacitor are converted into voltages, and these are input to the control device 70 as detection signals indicating the first capacitor and the second capacitor. Then, the control device 70 performs rough detection of the driving vibration of the driving / detecting weight 32 based on the detection signal indicating the first capacity, and the driving / detecting weight 32 based on the detection signal indicating the second capacity. The fine vibration of the driving vibration is detected.

例えば、第１容量や第２容量の変化に対応した電圧を所定の分解能で検出する。その場合、第１容量については駆動振動の振動全域において変化するが、所定の振動量に対する第１容量の変化量およびそれに対応する電圧変化量は小さい。一方、第２容量については駆動振動の振動量が最も大きくなるときに近づいた場合にだけ大きく変化し、そのときの所定の振動量に対する第２容量の変化量およびそれに対応する電圧変化量は大きい。 For example, a voltage corresponding to a change in the first capacitance or the second capacitance is detected with a predetermined resolution. In this case, the first capacitor changes in the entire vibration range of the drive vibration, but the change amount of the first capacitor and the corresponding voltage change amount with respect to the predetermined vibration amount are small. On the other hand, the second capacitor changes greatly only when the amount of vibration of the driving vibration approaches the maximum, and the amount of change in the second capacitor and the voltage change corresponding to the predetermined amount of vibration at that time are large. .

このため、制御装置７０の電圧検出の分解能が高くなくても、第１容量の変化に対応する電圧変化量に基づいて駆動振動の全域において粗動検出が行え、第２容量の変化に対応する電圧変化量に基づいて、振動量が最も大きくなるときに近づくと微動検出が行える。 For this reason, even if the resolution of the voltage detection of the control device 70 is not high, coarse motion detection can be performed in the entire region of the drive vibration based on the voltage change amount corresponding to the change in the first capacitance, and the change in the second capacitance is supported. Based on the amount of voltage change, fine movement detection can be performed when the vibration amount approaches the maximum.

ここで、制御装置７０の検出精度を向上させるのには、制御装置７０による電圧検出の分解能を上げること、すなわち電圧変化量をより細かく検出できるようにすることが考えられる。しかしながら、分解能は電圧変化量を検出する回路のビット数によって決まり、分解能を上げるためには回路ビット数を増やさなければならない。 Here, in order to improve the detection accuracy of the control device 70, it is conceivable to increase the resolution of voltage detection by the control device 70, that is, to make it possible to detect the voltage change amount more finely. However, the resolution is determined by the number of bits of the circuit that detects the amount of voltage change, and the number of circuit bits must be increased in order to increase the resolution.

一方、制御装置７０による駆動振動の検出精度が要求されるのは、駆動振動の振幅精度を向上させるためである。そして、駆動振動の振幅精度を向上させるために必要なのは、駆動振動の全域において駆動振動の検出精度を向上させることではなく、駆動振動の振動量が最も大きくなる近辺において駆動振動の検出精度を向上させることである。 On the other hand, the detection accuracy of the drive vibration by the control device 70 is required in order to improve the amplitude accuracy of the drive vibration. What is needed to improve the amplitude accuracy of the drive vibration is not to improve the detection accuracy of the drive vibration in the entire area of the drive vibration, but to improve the detection accuracy of the drive vibration in the vicinity where the vibration amount of the drive vibration is the largest. It is to let you.

このため、本実施形態では、可動櫛歯電極６１と固定櫛歯電極６４とによって、駆動振動に基づいて緩やかに変化する第１容量を構成する。この第１容量に基づいて振動位置の粗動検出を行うことで、駆動振動の全域において振動位置を確認する。また、可動平面電極６２と固定平面電極６６とによって、駆動振動の振動量が最も大きくなる振動位置に近づくと大きく変化する第２容量を構成する。この第２容量に基づいて微動検出を行うことで、回路ビット数を増やさなくても振動振幅の検出精度を高めることが可能となる。 For this reason, in this embodiment, the movable comb electrode 61 and the fixed comb electrode 64 constitute a first capacitor that gradually changes based on the drive vibration. By detecting the coarse movement of the vibration position based on the first capacity, the vibration position is confirmed in the entire drive vibration. Further, the movable flat electrode 62 and the fixed flat electrode 66 constitute a second capacitor that greatly changes when approaching a vibration position where the vibration amount of the drive vibration becomes the largest. By performing fine motion detection based on the second capacity, it is possible to improve the vibration amplitude detection accuracy without increasing the number of circuit bits.

例えば、駆動振動の振幅が３０μｍと大きい場合であっても、駆動振動の全域で０．０３μｍの精度で検出する必要は無く、駆動振動の振幅量が最も大きくなる振動位置で０．０３μｍの精度で検出することが可能となる。 For example, even when the amplitude of the drive vibration is as large as 30 μm, it is not necessary to detect with an accuracy of 0.03 μm over the entire range of the drive vibration, and an accuracy of 0.03 μm at the vibration position where the amplitude amount of the drive vibration is the largest. Can be detected.

このように、駆動振動の振幅量が最も大きくなる振動位置に近づいたときに、第２容量の変化に基づいて検出精度の高い第２精度で検出できるため、残りの領域では第１容量の変化に基づく検出精度の低い第１精度に落とすことができる。したがって、回路ビット数を増やさなくても、検出精度を高めたい振動位置において、所望の検出精度で駆動振動の振動量を検出することができる。 In this way, when the vibration position approaches the vibration position where the amplitude amount of the drive vibration becomes the largest, it can be detected with the second accuracy with high detection accuracy based on the change in the second capacitance, and therefore the change in the first capacitance in the remaining region. Can be reduced to the first accuracy with low detection accuracy. Therefore, even if the number of circuit bits is not increased, the vibration amount of the drive vibration can be detected with a desired detection accuracy at the vibration position where the detection accuracy is desired to be increased.

なお、第２容量の変化に基づく微動検出を行う範囲と、第２容量構成部が構成する第２容量の容量値および容量変化の定め方次第で、検出精度を自由に変更することが可能である。 The detection accuracy can be freely changed depending on the range in which the fine movement detection based on the change in the second capacitance is performed, the capacitance value of the second capacitance configured by the second capacitance configuration unit, and how the capacitance change is determined. is there.

（第２実施形態）
本発明の第２実施形態について説明する。本実施形態は、第１実施形態に対して第２容量構成部の構成を変更したものであり、その他については第１実施形態と同様であるため、第１実施形態と異なる部分についてのみ説明する。なお、
本実施形態では、第１実施形態で説明した可動平面電極６２や電極固定部６５および固定平面電極６６を無くしている。その代わりに、図１０に示すように、第２容量構成部を構成する可動櫛歯部６７と固定櫛歯部６８を備えている。なお、図１０では、駆動兼検出用錘３２およびその周囲に備えられる駆動振動検出部６０を示しているが、駆動兼検出用錘３１およびその周囲にも同様の構造のものが備えられている。 (Second Embodiment)
A second embodiment of the present invention will be described. In the present embodiment, the configuration of the second capacity configuration unit is changed with respect to the first embodiment, and the other parts are the same as those in the first embodiment. Therefore, only the parts different from the first embodiment will be described. . In addition,
In the present embodiment, the movable flat electrode 62, the electrode fixing portion 65, and the fixed flat electrode 66 described in the first embodiment are eliminated. Instead, as shown in FIG. 10, a movable comb-tooth portion 67 and a fixed comb-tooth portion 68 constituting the second capacity component portion are provided. In FIG. 10, the driving / detecting weight 32 and the driving vibration detecting unit 60 provided around the driving / detecting weight 32 are shown, but the driving / detecting weight 31 and the surrounding thereof are also provided with the same structure. .

可動櫛歯部６７は、可動櫛歯電極６１の間に配置されており、ｘ軸方向に延びるように構成されている。ただし、可動櫛歯部６７におけるｘ軸方向寸法は可動櫛歯電極６１よりも小さくされている。具体的には、駆動兼検出用錘３２の駆動振動が小さいときには可動櫛歯部６７が固定櫛歯部６８と対向せず、駆動振動の最も振動量が大きくなるときに近づくと可動櫛歯部６７が固定櫛歯部６８と対向する程度に、可動櫛歯部６７のｘ軸方向寸法が設定されている。 The movable comb portion 67 is disposed between the movable comb electrodes 61 and is configured to extend in the x-axis direction. However, the dimension in the x-axis direction of the movable comb tooth portion 67 is smaller than that of the movable comb electrode 61. Specifically, when the driving vibration of the driving and detecting weight 32 is small, the movable comb tooth portion 67 does not face the fixed comb tooth portion 68, and when the vibration amount of the driving vibration becomes maximum, the movable comb tooth portion 67 approaches. The dimension of the movable comb tooth portion 67 in the x-axis direction is set such that 67 faces the fixed comb tooth portion 68.

固定櫛歯部６８は、固定櫛歯電極６４の先端に備えられており、固定櫛歯電極６４の先端から更にｘ軸方向に延びるように形成されている。ただし、固定櫛歯部６８におけるｘ軸方向寸法は固定櫛歯電極６４よりも小さくされている。具体的には、駆動兼検出用錘３２の駆動振動が小さいときには固定櫛歯部６８が可動櫛歯部６７と対向せず、駆動振動の最も振動量が大きくなるときに近づくと固定櫛歯部６８が可動櫛歯部６７と対向する程度に、固定櫛歯部６８のｘ軸方向寸法が設定されている。 The fixed comb-tooth portion 68 is provided at the tip of the fixed comb-tooth electrode 64 and is formed so as to extend further in the x-axis direction from the tip of the fixed comb-tooth electrode 64. However, the dimension in the x-axis direction of the fixed comb tooth portion 68 is smaller than that of the fixed comb tooth electrode 64. Specifically, when the driving vibration of the driving and detecting weight 32 is small, the fixed comb tooth portion 68 does not face the movable comb tooth portion 67, and the fixed comb tooth portion approaches when the vibration amount of the driving vibration becomes the largest. The dimension of the fixed comb tooth portion 68 in the x-axis direction is set such that 68 faces the movable comb tooth portion 67.

このような構成において、本実施形態では、可動櫛歯電極６１と固定櫛歯電極６４との間に構成される容量を第１容量とし、可動櫛歯部６７と固定櫛歯部６８との間に構成される容量を第２容量として、これらの容量の変化を制御装置７０に出力する。ただし、本実施形態の場合、可動櫛歯部６７が駆動兼検出用錘３２に備えられ、固定櫛歯部６８が固定櫛歯部６８に備えられている。このため、駆動兼検出用錘３２と櫛歯固定部６３との間の容量をＣ−Ｖ変換回路８０によって電圧変換して取り出すと、第１容量の変化に第２容量の変化が重畳された合成容量の変化を示す電圧値を取り出すことになる。 In such a configuration, in the present embodiment, a capacity formed between the movable comb electrode 61 and the fixed comb electrode 64 is defined as a first capacity, and between the movable comb tooth portion 67 and the fixed comb tooth portion 68. And the change in these capacities is output to the control device 70. However, in the case of this embodiment, the movable comb tooth portion 67 is provided in the driving and detecting weight 32, and the fixed comb tooth portion 68 is provided in the fixed comb tooth portion 68. For this reason, when the capacitance between the driving / detecting weight 32 and the comb fixing portion 63 is converted by the CV conversion circuit 80 and taken out, the change in the second capacitance is superimposed on the change in the first capacitance. A voltage value indicating a change in the combined capacitance is taken out.

図１１は、駆動兼検出用錘３２の駆動振動に伴う第１容量に第２容量が重畳された合成容量の変化の一例を示している。図１１に示されるように、第１容量の変化に基づいてサイン波状の変化を示すが、駆動振動の振動量が最も大きくなる近辺において、可動櫛歯部６７と固定櫛歯部６８とが対向し、第２容量の変化に基づく急峻な変化が重畳される。 FIG. 11 shows an example of a change in the combined capacity in which the second capacity is superimposed on the first capacity due to the drive vibration of the drive / detection weight 32. As shown in FIG. 11, a sine wave-like change is shown based on the change in the first capacitance, but the movable comb teeth 67 and the fixed comb teeth 68 face each other in the vicinity where the vibration amount of the drive vibration becomes the largest. However, a steep change based on the change in the second capacitance is superimposed.

したがって、このような合成容量の変化に対応する電圧値変化をモニタすることで、駆動兼検出用錘３２の駆動振動の振動位置を検出できる。そして、第２容量の変化に基づく急峻な変化については第１実施形態と同様であることから、これに基づいて微動検出を行うことで、回路ビット数を増やさなくても振動振幅の検出精度を高めることが可能となる。 Therefore, the vibration position of the drive vibration of the drive / detection weight 32 can be detected by monitoring the voltage value change corresponding to such a change in the combined capacitance. Since the steep change based on the change in the second capacitance is the same as in the first embodiment, the detection accuracy of vibration amplitude can be improved without increasing the number of circuit bits by performing fine movement detection based on this. It becomes possible to raise.

（他の実施形態）
本発明は上記した実施形態に限定されるものではなく、特許請求の範囲に記載した範囲内において適宜変更が可能である。 (Other embodiments)
The present invention is not limited to the embodiment described above, and can be appropriately changed within the scope described in the claims.

例えば、駆動兼検出用錘３１、３２を用いることで、駆動錘と検出錘の両方を兼用したものとしたが、別々に備えた構造であっても良い。 For example, the driving and detection weights 31 and 32 are used so that both the driving weight and the detection weight are used, but a structure provided separately may be used.

また、駆動振動検出部６０における第１容量構成部や第２容量構成部として、上記と異なる構成のものとしても良い。具体的には、図６に示したように、駆動兼検出用錘３１、３２のうちｙ軸方向に平行な各側面やそれに対向する位置に設けた櫛歯固定部６３に可動櫛歯電極６１と固定櫛歯電極６４を２箇所に分けて配置し、その間に可動平面電極６２や固定平面電極６６を配置した。これは第１容量構成部や第２容量構成部の一例を示したに過ぎない。例えば、可動櫛歯電極６１と固定櫛歯電極６４を２箇所に分けて配置しなくても良い。また、可動櫛歯電極６１や固定櫛歯電極６４と可動平面電極６２や固定平面電極６６を配置する場所を異ならせ、例えば一方を駆動兼検出用錘３１、３２のうちｘ軸と平行な一面に形成しても良い。 Moreover, it is good also as a thing different from the above as a 1st capacity | capacitance structure part in the drive vibration detection part 60, or a 2nd capacity | capacitance structure part. Specifically, as shown in FIG. 6, the movable comb electrode 61 is mounted on the comb fixing portions 63 provided on the side surfaces parallel to the y-axis direction of the driving and detection weights 31 and 32 or on the positions facing the side surfaces. And the fixed comb electrode 64 are arranged in two places, and the movable flat electrode 62 and the fixed flat electrode 66 are arranged therebetween. This is merely an example of the first capacity component and the second capacity component. For example, the movable comb electrode 61 and the fixed comb electrode 64 may not be arranged in two places. Further, the movable comb electrode 61 or the fixed comb electrode 64 and the movable flat electrode 62 or the fixed flat electrode 66 are arranged at different positions. For example, one of the driving and detection weights 31 and 32 is parallel to the x axis. You may form in.

なお、上記各実施形態では、駆動振動検出部６０の各振動検出部をそれぞれｘ軸、ｙ軸に平行な直線を中心とした線対称形状で形成したが、必ずしも線対称形状にする必要はない。ただし、線対称形状にすると、対称配置された各素子それぞれから検出信号を得て、それらの差動を取ることで、不要振動成分のキャンセルが可能になるなど、より精度良い角速度検出を行うことが可能になる。 In each of the above embodiments, each vibration detection unit of the drive vibration detection unit 60 is formed in a line-symmetric shape centered on a straight line parallel to the x-axis and the y-axis, but it is not always necessary to have a line-symmetric shape. . However, if a line-symmetric shape is used, detection of the angular velocity can be performed with higher accuracy, such as obtaining detection signals from each symmetrically arranged element and taking the differential between them to enable cancellation of unnecessary vibration components. Is possible.

また、上記実施形態では、検出梁４１や駆動梁４２のうち支持部材４３の近傍にのみ、駆動部５１や振動検出部５３を備えた構造とした。これについても単なる一例を示したに過ぎず、例えば検出梁４１や駆動梁４２の全域にこれらを設けるようにしても良い。 In the above embodiment, the drive unit 51 and the vibration detection unit 53 are provided only in the vicinity of the support member 43 in the detection beam 41 and the drive beam 42. This is merely an example, and these may be provided in the entire area of the detection beam 41 and the drive beam 42, for example.

さらに、上記実施形態では、駆動部５１として、圧電膜を用いて駆動振動を行わせる圧電タイプのものを用いたが、静電気力を用いて駆動振動を行わせる静電タイプのものを用いても良い。 Further, in the above-described embodiment, a piezoelectric type that performs driving vibration using a piezoelectric film is used as the driving unit 51. However, an electrostatic type that performs driving vibration using electrostatic force may be used. good.

１０基板
２０固定部
３０可動部
３１、３２駆動兼検出用錘
４０梁部
４１検出梁
４２駆動梁
５１駆動部
５３振動検出部
６０駆動振動検出部 DESCRIPTION OF SYMBOLS 10 Board | substrate 20 Fixed part 30 Movable part 31, 32 Weight for drive and detection 40 Beam part 41 Detection beam 42 Drive beam 51 Drive part 53 Vibration detection part 60 Drive vibration detection part

Claims

A vibration type angular velocity sensor,
A fixing part (20) fixed to the substrate (10);
A movable part (30) having a drive weight (31, 32) and a detection weight (31, 32);
A driving beam (42) for supporting the driving weight on a plane parallel to the plane of the substrate and supporting the fixed portion, and the detection weight can be moved on a plane parallel to the plane of the substrate. And a beam portion (40) having a detection beam (41) that supports the fixed portion,
A first capacity component (61, 64) that constitutes a first capacity that changes with a first change amount in accordance with a vibration amount of the drive vibration of the drive weight;
A second capacity component (62, 66) that constitutes a second capacity that changes with a second change amount that is steeper than the first change amount in accordance with a vibration amount of the drive vibration of the drive weight;
The drive weight is driven to vibrate in one direction on the plane of the substrate, and angular velocity detection is performed based on the fact that the detection weight vibrates in the direction perpendicular to the one direction on the plane of the substrate as the angular velocity is applied. A control device (70),
The control device detects a vibration amount of the drive vibration of the drive weight with a first accuracy based on the change in the first capacitance, and a second higher than the first accuracy based on the change in the second capacitance. The vibration position where the vibration amount in the drive vibration of the drive weight is the largest is detected with accuracy ,
Drive and detection weights (31, 32) serving as the drive weight and the detection weight are arranged on both sides of the fixed portion as the center in the same direction as the direction of the drive vibration,
The detection beam (41) extends on both sides in a direction perpendicular to the direction of the drive vibration, with the fixed portion as a center,
The drive beam (42) extends on both sides in a direction perpendicular to the direction of the drive vibration, with the drive / detection weight as the center.
The detection beam is connected to a linear support member (43) on the opposite side to the fixed portion and the drive beam on the opposite side to the driving and detection weight.
The drive / detection weight has a movable comb electrode (61) extending in the direction of the drive vibration and a movable flat electrode (62) formed on one surface with the direction of the drive vibration as a normal direction. ,
The first capacitor constituting unit constitutes the first capacitor by the movable comb electrode and the fixed comb electrode (64) which is disposed opposite to the movable comb electrode and fixed to the substrate. ,
The second capacitor constituting unit constitutes the second capacitor by the movable plane electrode and a fixed plane electrode (66) which is disposed opposite to the movable plane electrode and fixed to the substrate. And
A vibration type angular velocity sensor in which the fixed comb electrode and the fixed planar electrode are separately provided .

A vibration type angular velocity sensor,
A fixing part (20) fixed to the substrate (10);
A movable part (30) having a drive weight (31, 32) and a detection weight (31, 32);
A driving beam (42) for supporting the driving weight on a plane parallel to the plane of the substrate and supporting the fixed portion, and the detection weight can be moved on a plane parallel to the plane of the substrate. And a beam portion (40) having a detection beam (41) that supports the fixed portion,
A first capacity component (61, 64) that constitutes a first capacity that changes with a first change amount in accordance with a vibration amount of the drive vibration of the drive weight;
A second capacity component (62, 66) that constitutes a second capacity that changes with a second change amount that is steeper than the first change amount in accordance with a vibration amount of the drive vibration of the drive weight;
The drive weight is driven to vibrate in one direction on the plane of the substrate, and angular velocity detection is performed based on the fact that the detection weight vibrates in the direction perpendicular to the one direction on the plane of the substrate as the angular velocity is applied. A control device (70),
The control device detects a vibration amount of the drive vibration of the drive weight with a first accuracy based on the change in the first capacitance, and a second higher than the first accuracy based on the change in the second capacitance. The vibration position where the vibration amount in the drive vibration of the drive weight is the largest is detected with accuracy,
Drive and detection weights (31, 32) serving as the drive weight and the detection weight are arranged on both sides of the fixed portion as the center in the same direction as the direction of the drive vibration,
The detection beam (41) extends on both sides in a direction perpendicular to the direction of the drive vibration, with the fixed portion as a center,
The drive beam (42) extends on both sides in a direction perpendicular to the direction of the drive vibration, with the drive / detection weight as the center.
The detection beam is connected to a linear support member (43) on the opposite side to the fixed portion and the drive beam on the opposite side to the driving and detection weight.
The drive / detection weight has a movable comb electrode (61) extending in the direction of the drive vibration, and a movable comb tooth portion (67) extending in the direction of the drive vibration between the movable comb electrodes. ,
The first capacitor constituting unit constitutes the first capacitor by the movable comb electrode and the fixed comb electrode (64) which is disposed opposite to the movable comb electrode and fixed to the substrate. ,
The second capacity component part constitutes the second capacity by the movable comb tooth part and the fixed comb tooth part (68) extended in the driving vibration direction at the tip of the fixed comb electrode. dynamic type angular velocity sensor vibration that.

The second change amount of the second capacitance component increases as it approaches the vibration position where the vibration amount in the drive vibration of the drive weight is the largest, compared to when it is away from the vibration position. 3. The vibration type angular velocity sensor according to 1 or 2 .