JP2008122263A - Angular velocity sensor - Google Patents

Angular velocity sensor Download PDF

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JP2008122263A
JP2008122263A JP2006307437A JP2006307437A JP2008122263A JP 2008122263 A JP2008122263 A JP 2008122263A JP 2006307437 A JP2006307437 A JP 2006307437A JP 2006307437 A JP2006307437 A JP 2006307437A JP 2008122263 A JP2008122263 A JP 2008122263A
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arm
angular velocity
axis
axis direction
weight
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Jiro Terada
二郎 寺田
Takami Ishida
貴巳 石田
Ichiro Sato
佐藤　　一郎
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Panasonic Holdings Corp
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Matsushita Electric Industrial Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide an angular velocity sensor that allows a low profile design. <P>SOLUTION: The sensor includes a detection element 1 having two rectangular arms formed by connecting a first arm 2 to a second arm 4 approximately in the rectangular direction, a support part 6 for supporting two first arms 2, a fixed part 9 connected to the support part 6 and fixed to a mounting substrate, and a weight part 11 connected to the tip part of the second arm 4. The sensor has an arrangement wherein the second arm 4 is bent up to the facing state to the second arm 4 itself, and is provided with a driving means 17 for driving and vibrating the weight part in the facing direction to the second arm 4, and a first driving electrode part 17a and a second driving electrode part 17b are arranged in the mutually crossing state from the first arm 2 side of the bent second arm 4 toward the weight part 11 side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、航空機、自動車、ロボット、船舶、車両等の移動体の姿勢制御やナビゲーション等、各種電子機器に用いる角速度を検出する角速度センサに関するものである。   The present invention relates to an angular velocity sensor that detects angular velocities used in various electronic devices such as attitude control and navigation of moving bodies such as airplanes, automobiles, robots, ships, and vehicles.

以下、従来の角速度センサについて説明する。   Hereinafter, a conventional angular velocity sensor will be described.

従来の角速度センサは、例えば、音さ形状やＨ形状やＴ形状等、各種形状の検出素子を振動させ、コリオリ力の発生に伴う検出素子の歪を電気的に検知して角速度を検出する。   Conventional angular velocity sensors, for example, vibrate detection elements of various shapes such as sound shape, H shape, T shape, etc., and electrically detect distortion of the detection elements accompanying the generation of Coriolis force to detect the angular velocity.

例えば、互いに略直交したＸ軸とＹ軸とＺ軸において、Ｘ軸とＹ軸とのＸＹ平面に車両を配置した場合、ナビゲーション装置用の角速度センサでは、車両のＺ軸周りの角速度を検出している。   For example, when a vehicle is arranged on the XY plane of the X axis and the Y axis on the X axis, the Y axis, and the Z axis substantially orthogonal to each other, the angular velocity sensor for the navigation device detects the angular velocity around the Z axis of the vehicle. ing.

図４は従来の角速度センサの斜視図、図５は同角速度センサのＡ−Ａ断面図である。   4 is a perspective view of a conventional angular velocity sensor, and FIG. 5 is a cross-sectional view taken along the line AA of the angular velocity sensor.

図４、図５において、従来の角速度センサの検出素子５１は音さ形状であって、２本のアーム５２と、このアーム５２を連結した基部５３とを有する。   4 and 5, the detection element 51 of the conventional angular velocity sensor has a sound shape and includes two arms 52 and a base 53 connecting the arms 52.

２本のアーム５２にはアーム５２を駆動振動させる駆動電極部５４や角速度に起因したアーム５２の歪を感知する感知電極部５５が配置されており、例えば、各々の駆動電極部５４や感知電極部５５は圧電体５６を介在させた上部電極５７と下部電極５８から形成されている。また、この駆動電極部５４および感知電極部５５からは信号線５９が引き出され、基部５３に形成した電極パッド６０まで配置されている。さらに、電極パッド６０からワイヤボンディング等を介して検出素子５１を実装する実装基板（図示せず）の配線パターンに電気的に接続されている。   The two arms 52 are provided with a drive electrode portion 54 that drives and vibrates the arm 52 and a sense electrode portion 55 that senses the distortion of the arm 52 caused by the angular velocity. For example, each of the drive electrode portions 54 and the sense electrodes The portion 55 is formed by an upper electrode 57 and a lower electrode 58 with a piezoelectric body 56 interposed therebetween. Further, a signal line 59 is drawn from the drive electrode portion 54 and the sensing electrode portion 55, and the electrode pad 60 formed on the base portion 53 is arranged. Furthermore, the electrode pad 60 is electrically connected to a wiring pattern of a mounting substrate (not shown) on which the detection element 51 is mounted via wire bonding or the like.

上記検出素子を、例えば、ＸＹ平面に対してＺ軸方向に立設し、アーム５２をＸ軸方向に駆動振動させ、Ｚ軸周りの角速度に起因した歪をアーム５２で感知することにより、Ｚ軸周りの角速度を検出していた。このような検出素子５１では、アーム５２の駆動振動面（ＸＺ平面）とアーム５２の歪面（ＹＺ平面）とは互いに略直交面となり、また、一方のアーム５２と他方のアーム５２では歪の方向が逆方向となる（一方のアーム５２が正のＹ軸方向に歪めば、他方のアーム５２は負のＹ軸方向に歪む）。   For example, the detection element is erected in the Z-axis direction with respect to the XY plane, the arm 52 is driven to vibrate in the X-axis direction, and the distortion caused by the angular velocity around the Z-axis is sensed by the arm 52. The angular velocity around the axis was detected. In such a detection element 51, the driving vibration surface (XZ plane) of the arm 52 and the distortion surface (YZ plane) of the arm 52 are substantially orthogonal to each other. The direction is opposite (if one arm 52 is distorted in the positive Y-axis direction, the other arm 52 is distorted in the negative Y-axis direction).

なお、この出願の発明に関連する先行技術文献情報としては、例えば、特許文献１が知られている。
特開２００５−２０１６５２号公報 As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
Japanese Patent Laying-Open No. 2005-201652

上記構成では、Ｚ軸周りの角速度を検出する場合、検出素子５１をＺ軸方向に立設する必要があり、低背化を図れないという問題点を有していた。   In the above configuration, when detecting the angular velocity around the Z-axis, the detection element 51 needs to be erected in the Z-axis direction, resulting in a problem that the height cannot be reduced.

本発明は上記問題点を解決し、Ｚ軸周りの角速度を検出する場合でも低背化を図れる角速度センサを提供することを目的としている。   An object of the present invention is to solve the above problems and to provide an angular velocity sensor capable of reducing the height even when the angular velocity around the Z axis is detected.

上記目的を達成するために本発明は、第１アームを第２アームに略直交方向に連結して形成した２つの直交アームと、２つの前記第１アームの一端を支持した支持部と、前記第１アームの他端を連結するとともに実装基板に固定する固定部と、前記第２アームの先端部に連結した錘部と、前記錘部を駆動振動させる駆動手段とを有する検出素子を備え、互いに直交するＸ軸、Ｙ軸、Ｚ軸において、前記錘部をＸ軸方向に駆動振動させるように前記固定部をＸＹ平面に配置した場合、前記錘部のＸ軸方向への共振周波数と前記錘部のＹ軸方向への共振周波数とを異ならせた構成である。   In order to achieve the above object, the present invention provides two orthogonal arms formed by connecting a first arm to a second arm in a substantially orthogonal direction, a support portion supporting two ends of the first arm, A detection element having a fixing part for connecting the other end of the first arm and fixing to the mounting substrate; a weight part connected to the tip part of the second arm; and a driving means for driving and vibrating the weight part; When the fixed part is arranged on the XY plane so as to drive and vibrate the weight part in the X-axis direction in the X axis, the Y axis, and the Z axis orthogonal to each other, the resonance frequency of the weight part in the X axis direction and the The resonance frequency in the Y-axis direction of the weight portion is different.

上記構成により、互いに直交したＸ軸、Ｙ軸、Ｚ軸において、検出素子の第１アームをＸ軸方向に配置し第２アームをＹ軸方向に配置して、Ｚ軸周りに角速度が生じた場合は、錘部の駆動振動と同調して、錘部には駆動振動方向と直交した方向にコリオリ力が発生する。よって、第２アームにＺ軸周りの角速度に起因した歪を発生させることができ、この歪を検知することにより角速度を検出できるので、検出素子をＺ軸方向に立設せずに伏せた状態で、Ｚ軸周りの角速度を検出でき低背化を図れる。   With the configuration described above, in the X, Y, and Z axes orthogonal to each other, the first arm of the detection element is arranged in the X axis direction and the second arm is arranged in the Y axis direction, resulting in an angular velocity around the Z axis. In this case, a Coriolis force is generated in the direction perpendicular to the driving vibration direction in synchronization with the driving vibration of the weight part. Therefore, the second arm can generate a strain caused by the angular velocity around the Z axis, and the angular velocity can be detected by detecting this strain. Thus, the angular velocity around the Z axis can be detected, and the height can be reduced.

特に、互いに直交するＸ軸、Ｙ軸、Ｚ軸において、錘部をＸ軸方向に駆動振動させるように固定部をＸＹ平面に配置した場合、前記錘部のＸ軸方向への共振周波数と前記錘部のＹ軸方向への共振周波数とを異ならせているので、錘部を的確にＸ軸方向へ駆動振動させることができる。Ｘ軸方向への共振周波数とＺ軸方向への共振周波数とが等しい場合は、Ｘ軸方向へ駆動振動させようとしてもＺ軸方向にも変位して、駆動振動方向が安定せず、角速度の検出ができない恐れがある。   In particular, in the X axis, the Y axis, and the Z axis orthogonal to each other, when the fixed part is arranged on the XY plane so as to drive and vibrate the weight part in the X axis direction, the resonance frequency in the X axis direction of the weight part and the Since the resonance frequency of the weight portion in the Y-axis direction is different, the weight portion can be accurately driven and vibrated in the X-axis direction. If the resonance frequency in the X-axis direction and the resonance frequency in the Z-axis direction are equal, the drive vibration in the X-axis direction is displaced in the Z-axis direction, the drive vibration direction is not stable, and the angular velocity There is a possibility that it cannot be detected.

なお、第２アームの幅を大きくすると錘部のＸ軸方向への共振周波数とＹ軸方向への共振周波数との周波数差が小さくなり、第２アームの幅を小さくすると錘部のＸ軸方向への共振周波数とＹ軸方向への共振周波数との周波数差が大きくなる。この周波数差が大きくなりすぎると感度が低下するので、周波数差は１００〜５００Ｈｚになるようにするのが望ましい。   If the width of the second arm is increased, the frequency difference between the resonance frequency of the weight portion in the X-axis direction and the resonance frequency in the Y-axis direction is reduced, and if the width of the second arm is reduced, the X-axis direction of the weight portion is reduced. The difference in frequency between the resonance frequency to and the resonance frequency in the Y-axis direction becomes large. If this frequency difference becomes too large, the sensitivity decreases, so it is desirable that the frequency difference be 100 to 500 Hz.

図１は本発明の一実施の形態における角速度センサの検出素子の斜視図である。   FIG. 1 is a perspective view of a detection element of an angular velocity sensor according to an embodiment of the present invention.

図１において、本発明の一実施の形態における角速度センサは、角速度を検出する検出素子１を備え、この検出素子１は、第１アーム２を第２アーム４に略直交方向に連結して形成した２つの直交アームを有し、２つの第１アーム２の一端を支持する支持部６と、支持部６の他端を連結するとともに実装基板（図示せず）に固定する固定部９とを有する。   In FIG. 1, an angular velocity sensor according to an embodiment of the present invention includes a detection element 1 that detects angular velocity, and this detection element 1 is formed by connecting a first arm 2 to a second arm 4 in a substantially orthogonal direction. A support portion 6 that has two orthogonal arms and supports one end of the two first arms 2, and a fixing portion 9 that connects the other end of the support portion 6 and fixes it to a mounting board (not shown). Have.

第２アーム４はＵ字状に折曲して第２アーム４自身と対向する対向部１６を設け、その先端には錘部１１を連結している。   The second arm 4 is bent in a U shape and is provided with a facing portion 16 facing the second arm 4 itself, and a weight portion 11 is connected to the tip thereof.

この検出素子１は、第１アーム２と支持部６とを略同一直線上に配置しており、互いに直交したＸ軸、Ｙ軸、Ｚ軸において、第１アーム２をＸ軸方向に配置した場合、第２アーム４がＹ軸方向に配置される。特に、錘部１１のＸ軸方向への共振周波数と錘部１１のＹ軸方向への共振周波数とを異ならせている。   In this detection element 1, the first arm 2 and the support portion 6 are arranged on substantially the same straight line, and the first arm 2 is arranged in the X-axis direction on the X-axis, Y-axis, and Z-axis orthogonal to each other. In this case, the second arm 4 is arranged in the Y-axis direction. In particular, the resonance frequency of the weight portion 11 in the X-axis direction is different from the resonance frequency of the weight portion 11 in the Y-axis direction.

４つの第２アーム４の内、互いに対向する一方の２つの第２アーム４には錘部１１を駆動振動させる第１駆動手段１７および第１検知手段１８を設けるとともに、互いに対向する他方の２つの第２アーム４には第２アーム４の歪を感知する第１感知手段１９、第２感知手段２０を設けている。   Among the four second arms 4, one of the two second arms 4 facing each other is provided with a first driving means 17 and a first detection means 18 for driving and vibrating the weight portion 11, and the other two arms facing each other. Two second arms 4 are provided with first sensing means 19 and second sensing means 20 for sensing the distortion of the second arm 4.

この第１駆動手段１７は第２アーム４の錘部１１を駆動させるための電極部を有し、第１検知手段１８は第２アーム４の駆動状態を検知するための電極部を有し、一方の第２アーム４には、その内周部の第１アーム２側に第１駆動電極部１７ａを配置するとともに外周部の錘部１１側に第１駆動電極部１７ａを配置し、外周部の第１アーム２側に第２駆動電極部１７ｂを配置するとともに内周部の錘部１１側に第２駆動電極部１７ｂを配置しており、他方の第２アーム４には、その外周部の第１アーム２側に第１検知電極部１８ａを配置するとともに内周部の錘部１１側に第１検知電極部１８ａを配置し、内周部の第１アーム２側に第２検知電極部１８ｂを配置するとともに外周部の錘部１１側に第２検知電極部１８ｂを配置している。   The first driving means 17 has an electrode part for driving the weight part 11 of the second arm 4, and the first detection means 18 has an electrode part for detecting the driving state of the second arm 4, One second arm 4 has a first drive electrode portion 17a arranged on the first arm 2 side of the inner peripheral portion thereof and a first drive electrode portion 17a arranged on the weight portion 11 side of the outer peripheral portion. The second drive electrode portion 17b is disposed on the first arm 2 side and the second drive electrode portion 17b is disposed on the weight portion 11 side of the inner peripheral portion. The other second arm 4 has an outer peripheral portion. The first detection electrode portion 18a is disposed on the first arm 2 side of the first detection electrode portion 18a, the first detection electrode portion 18a is disposed on the inner peripheral portion of the weight portion 11 side, and the second detection electrode is disposed on the first arm 2 side of the inner peripheral portion. The part 18b is arranged, and the second detection electrode part 18b is arranged on the weight part 11 side of the outer peripheral part.

また、第１、第２駆動電極部１７ａ，１７ｂは互いに対向配置させるとともに、第１、第２検知電極部１８ａ，１８ｂは互いに対向配置させている。これによって、Ｕ字状に折曲した第２アーム４の第１アーム２側から錘部１１側に向かって、第１駆動電極部１７ａおよび第２駆動電極部１７ｂが互いに交差して配置されるとともに、第１検知電極部１８ａおよび第２検知電極部１８ｂが互いに交差して配置される。この第１、第２駆動電極部１７ａ，１７ｂおよび第１、第２検知電極部１８ａ，１８ｂは、図２に示すように、圧電体１３を介在させた下部電極１４と上部電極１５とからなる。   The first and second drive electrode portions 17a and 17b are arranged to face each other, and the first and second detection electrode portions 18a and 18b are arranged to face each other. Thus, the first drive electrode portion 17a and the second drive electrode portion 17b are arranged so as to cross each other from the first arm 2 side of the second arm 4 bent in a U shape toward the weight portion 11 side. At the same time, the first detection electrode portion 18a and the second detection electrode portion 18b are arranged so as to cross each other. The first and second drive electrode portions 17a and 17b and the first and second detection electrode portions 18a and 18b are composed of a lower electrode 14 and an upper electrode 15 with a piezoelectric body 13 interposed, as shown in FIG. .

さらに、錘部１１側に配置した第１駆動電極部１７ａから第１引き出し線２１ａを引き出すとともに、錘部１１側に配置した第２駆動電極部１７ｂから第２引き出し線２１ｂを引き出し、第１アーム２側に配置した第１駆動電極部１７ａと、第１アーム２側に配置した第２駆動電極部１７ｂとの間から、第１引き出し線２１ａおよび第２引き出し線２１ｂを引き出し、第１アーム２側に配置した第１駆動電極部１７ａから第３引き出し線２１ｃを引き出し、第２駆動電極部１７ｂから第４引き出し線２１ｄを引き出し、これら第１引き出し線２１ａ、第２引き出し線２１ｂ、第３引き出し線２１ｃ、第４引き出し線２１ｄを固定部９まで引き出して電極パッドに接続している。   Further, the first lead wire 21a is drawn out from the first drive electrode portion 17a arranged on the weight portion 11 side, and the second lead wire 21b is drawn out from the second drive electrode portion 17b arranged on the weight portion 11 side. The first lead line 21a and the second lead line 21b are led out from between the first drive electrode part 17a arranged on the second side and the second drive electrode part 17b arranged on the first arm 2 side. The third lead line 21c is drawn from the first drive electrode part 17a arranged on the side, the fourth lead line 21d is drawn from the second drive electrode part 17b, and these first lead line 21a, second lead line 21b, and third lead line are drawn. The line 21c and the fourth lead line 21d are led out to the fixing portion 9 and connected to the electrode pad.

第１感知手段１９および第２感知手段２０は、２つの第２アーム４の歪を感知させるための電極部であり、一方の第２アーム４には、その内周部の第１アーム２側に第１感知電極部１９ａを配置するとともに外周部の錘部１１側に第１感知電極部１９ａを配置し、外周部の第１アーム２側に第２感知電極部１９ｂを配置するとともに内周部の錘部１１側に第２感知電極部１９ｂを配置しており、他方の第２アーム４には、その外周部の第１アーム２側に第３感知電極部２０ａを配置するとともに内周部の錘部１１側に第３感知電極部２０ａを配置し、内周の第１アーム２側に第４感知電極部２０ｂを配置するとともに外周部の錘部１１側に第４感知電極部２０ｂを配置している。   The first sensing means 19 and the second sensing means 20 are electrode portions for sensing the distortion of the two second arms 4. One of the second arms 4 has a first arm 2 side on the inner periphery thereof. The first sensing electrode portion 19a is disposed on the weight 11 side of the outer peripheral portion, the second sensing electrode portion 19b is disposed on the first arm 2 side of the outer peripheral portion, and the inner periphery. The second sensing electrode part 19b is disposed on the weight part 11 side of the first part, and the third sensing electrode part 20a is disposed on the first arm 2 side of the outer peripheral part of the other second arm 4 and the inner periphery. The third sensing electrode part 20a is arranged on the weight part 11 side of the part, the fourth sensing electrode part 20b is arranged on the inner arm side of the first arm 2, and the fourth sensing electrode part 20b is arranged on the weight part 11 side of the outer periphery part. Is arranged.

また、第１、第２感知電極部１９ａ，１９ｂは互いに対向配置させるとともに、第３、第４感知電極部２０ａ，２０ｂは互いに対向配置させている。これによって、Ｕ字状に折曲した第２アーム４の第１アーム２側から錘部１１側に向かって、第１感知電極部１９ａおよび第２感知電極部１９ｂが互いに交差して配置されるとともに、第３感知電極部２０ａおよび第４感知電極部２０ｂが互いに交差して配置される。この第１〜第４感知電極部１９ａ，１９ｂ，２０ａ，２０ｂは、図２に示すように、圧電体１３を介在させた下部電極１４と上部電極１５とからなる。   The first and second sensing electrode portions 19a and 19b are arranged to face each other, and the third and fourth sensing electrode portions 20a and 20b are arranged to face each other. Accordingly, the first sensing electrode portion 19a and the second sensing electrode portion 19b are arranged so as to cross each other from the first arm 2 side of the second arm 4 bent in a U shape toward the weight portion 11 side. In addition, the third sensing electrode unit 20a and the fourth sensing electrode unit 20b are arranged to cross each other. The first to fourth sensing electrode portions 19a, 19b, 20a, 20b are composed of a lower electrode 14 and an upper electrode 15 with a piezoelectric body 13 interposed, as shown in FIG.

さらに、錘部１１側に配置した第１感知電極部１９ａから第１引き出し線２２ａを引き出すとともに、錘部１１側に配置した第２感知電極部１９ｂから第２引き出し線２２ｂを引き出し、第１アーム２側に配置した第１感知電極部１９ａと、第１アーム２側に配置した第２感知電極部１９ｂとの間から、第１引き出し線２２ａおよび第２引き出し線２２ｂを引き出し、第１アーム２側に配置した第１感知電極部１９ａから第３引き出し線２２ｃを引き出し、第２感知電極部１９ｂから第４引き出し線２２ｄを引き出し、これら第１引き出し線２２ａ、第２引き出し線２２ｂ、第３引き出し線２２ｃ、第４引き出し線２２ｄを固定部９まで引き出して電極パッドに接続している。   Further, the first lead wire 22a is drawn out from the first sensing electrode portion 19a arranged on the weight portion 11 side, and the second lead wire 22b is drawn out from the second sense electrode portion 19b arranged on the weight portion 11 side, and the first arm The first lead wire 22a and the second lead wire 22b are led out from between the first sensing electrode portion 19a arranged on the second side and the second sensing electrode portion 19b arranged on the first arm 2 side, and the first arm 2 The third lead wire 22c is drawn from the first sensing electrode portion 19a arranged on the side, the fourth lead wire 22d is drawn from the second sense electrode portion 19b, and the first lead wire 22a, the second lead wire 22b, and the third lead wire are drawn. The line 22c and the fourth lead line 22d are drawn to the fixing portion 9 and connected to the electrode pad.

この結果、第１引き出し線２２ａおよび第２引き出し線２２ｂを互いに交差させることなく固定部９まで引き出せ、第１引き出し線２２ａと第２引き出し線２２ｂとの絶縁を図る必要もなく、容易に引き出すことができる。   As a result, the first lead line 22a and the second lead line 22b can be drawn to the fixing portion 9 without crossing each other, and the first lead line 22a and the second lead line 22b do not need to be insulated and can be easily drawn. Can do.

なお、第１、第２検知電極部１８ａ，１８ｂ、第３、第４感知電極部２０ａ，２０ｂも同様である。   The same applies to the first and second detection electrode portions 18a and 18b and the third and fourth detection electrode portions 20a and 20b.

上記の第１、第２駆動電極部１７ａ，１７ｂおよび第１、第２検知電極部１８ａ，１８ｂおよび第１〜第４感知電極部１９ａ，１９ｂ，２０ａ，２０ｂは、シリコン基板上にＰｔからなる下部電極１４を高周波スパッタにて形成し、この下部電極１４の上部にＰＺＴからなる圧電体１３を高周波スパッタにて形成し、ＰＺＴからなる圧電体１３の上部にＡｕからなる上部電極１５を蒸着にて形成すればよい。   The first and second drive electrode portions 17a and 17b and the first and second detection electrode portions 18a and 18b and the first to fourth sense electrode portions 19a, 19b, 20a and 20b are made of Pt on a silicon substrate. The lower electrode 14 is formed by high-frequency sputtering, the piezoelectric body 13 made of PZT is formed on the lower electrode 14 by high-frequency sputtering, and the upper electrode 15 made of Au is deposited on the upper portion of the piezoelectric body 13 made of PZT. May be formed.

第１、第２駆動電極部１７ａ，１７ｂに共振周波数の交流電圧を印加すると、第１駆動手段１７が配置された対向部１６を起点に第２アーム４が駆動振動するとともに、それに伴って、４つの第２アーム４および４つの錘部１１の全てが同調して駆動振動する。また、角速度に起因して第２アーム４が歪めば、第１〜第４感知電極部１９ａ，１９ｂ，２０ａ，２０ｂから歪に応じた電圧が出力され、この出力電圧に基づき、角速度を検出できる。   When an AC voltage having a resonance frequency is applied to the first and second drive electrode portions 17a and 17b, the second arm 4 is driven to vibrate from the opposing portion 16 where the first drive means 17 is disposed, and accordingly, All of the four second arms 4 and the four weight portions 11 are driven and vibrated in synchronization. If the second arm 4 is distorted due to the angular velocity, voltages corresponding to the strain are output from the first to fourth sensing electrode portions 19a, 19b, 20a, and 20b, and the angular velocity can be detected based on the output voltage. .

図３は同検出素子１の動作状態図である。   FIG. 3 is an operation state diagram of the detection element 1.

互いに直交したＸ軸、Ｙ軸、Ｚ軸において、検出素子１の第１アーム２をＸ軸方向に配置して、第２アーム４をＹ軸方向に配置した場合、第１、第２駆動電極部１７ａ，１７ｂに共振周波数の交流電圧を印加すると、第１駆動手段１７が配置された第２アーム４を起点に第２アーム４が駆動振動し、それに伴って錘部１１も第２アーム４の対向方向（実線の矢印と点線の矢印で記した駆動振動方向）に駆動振動する。また、４つの第２アーム４および４つの錘部１１の全てが同調して第２アーム４の対向方向に駆動振動する。この検出素子１における駆動振動方向はＸ軸方向となる。   When the first arm 2 of the detection element 1 is arranged in the X-axis direction and the second arm 4 is arranged in the Y-axis direction on the X, Y, and Z axes orthogonal to each other, the first and second drive electrodes When an AC voltage having a resonance frequency is applied to the parts 17a and 17b, the second arm 4 is driven and oscillated from the second arm 4 on which the first driving means 17 is disposed. In the opposite direction (the direction of the drive vibration indicated by the solid arrow and the dotted arrow). Further, all of the four second arms 4 and the four weight portions 11 are synchronously driven and vibrated in a direction opposite to the second arm 4. The driving vibration direction in the detection element 1 is the X-axis direction.

このとき、例えば、Ｚ軸の左回りに角速度が生じた場合は、錘部１１の駆動振動と同調して、錘部１１に対して駆動振動方向と直交した方向（実線の矢印と点線の矢印で記したコリオリ方向）にコリオリ力が発生するので、第２アーム４にＺ軸の左回りの角速度に起因した歪を発生させることができる。この検出素子１のコリオリ方向はＹ軸方向となる。   At this time, for example, when an angular velocity is generated in the counterclockwise direction of the Z axis, a direction (solid line arrow and dotted line arrow) perpendicular to the drive vibration direction with respect to the weight part 11 is synchronized with the drive vibration of the weight part 11. Since the Coriolis force is generated in the Coriolis direction indicated by (2), distortion caused by the counterclockwise angular velocity of the Z axis can be generated in the second arm 4. The Coriolis direction of the detection element 1 is the Y-axis direction.

実線の矢印で記したコリオリ方向にコリオリ力が発生した場合は、第１〜第４感知電極部１９ａ，１９ｂ，２０ａ，２０ｂが設けられた第２アーム４において、第１感知電極部１９ａと第３感知電極部２０ａが第２アーム４の縮みを感知するとともに第２感知電極部１９ｂと第４感知電極部２０ｂが第２アーム４の伸びを感知し、点線の矢印で記したコリオリ方向にコリオリ力が発生した場合は、その逆方向の伸び縮みを感知する。   When the Coriolis force is generated in the Coriolis direction indicated by the solid arrow, the first sensing electrode unit 19a and the first sensing electrode unit 19a are connected to the first sensing electrode unit 19a and the second sensing electrode unit 19a, 19b, 20a, and 20b. The third sensing electrode unit 20a senses the contraction of the second arm 4, and the second sensing electrode unit 19b and the fourth sensing electrode unit 20b sense the extension of the second arm 4, and coriolis in the Coriolis direction indicated by the dotted arrow. When a force is generated, it senses the expansion and contraction in the opposite direction.

そして、感知した伸び縮みに応じて、第１〜第４感知電極部１９ａ，１９ｂ，２０ａ，２０ｂから電圧が出力され、この出力電圧に基づき角速度が検出される。   A voltage is output from the first to fourth sensing electrode portions 19a, 19b, 20a, and 20b according to the sensed expansion / contraction, and the angular velocity is detected based on the output voltage.

一方、Ｚ軸の右回りに角速度が生じた場合は、Ｚ軸の左回りに角速度が生じた場合とは正反対に、第２アーム４の対向部１６が伸び縮みし、この伸び縮みを第１〜第４感知電極部１９ａ，１９ｂ，２０ａ，２０ｂが感知するので、同様に角速度が検出される。   On the other hand, when the angular velocity is generated clockwise around the Z axis, the opposite portion 16 of the second arm 4 is expanded and contracted in the opposite direction to the case where the angular velocity is generated counterclockwise about the Z axis. Since the fourth sensing electrode portions 19a, 19b, 20a, and 20b sense, the angular velocity is similarly detected.

また、Ｙ軸周りに角速度が生じた場合も、錘部１１の駆動振動と同調して、錘部１１に対して駆動振動方向と直交した方向（Ｚ軸方向）にコリオリ力が発生するので、第２アーム４にＹ軸周りの角速度に起因した歪を発生させ、第２アーム４の伸び縮みを第１〜第４感知電極部１９ａ，１９ｂ，２０ａ，２０ｂが感知することにより、角速度が検出される。   Also, when an angular velocity occurs around the Y axis, Coriolis force is generated in a direction (Z axis direction) perpendicular to the drive vibration direction with respect to the weight portion 11 in synchronization with the drive vibration of the weight portion 11. The second arm 4 is distorted due to the angular velocity around the Y axis, and the first to fourth sensing electrode portions 19a, 19b, 20a, and 20b sense the angular velocity by detecting the expansion and contraction of the second arm 4. Is done.

なお、Ｚ軸、Ｙ軸周りに角速度が生じた場合に発生する歪は、第１、第２駆動電極部１７ａ，１７ｂおよび第１、第２検知電極部１８ａ，１８ｂが設けられた第２アーム４にも同様に発生するので、第１〜第４感知電極部１９ａ，１９ｂ，２０ａ，２０ｂを第１、第２駆動電極部１７ａ，１７ｂおよび第１、第２検知電極部１８ａ，１８ｂが設けられた第２アーム４に配置することも可能である。   The distortion that occurs when angular velocities occur around the Z axis and Y axis is the second arm provided with the first and second drive electrode portions 17a and 17b and the first and second detection electrode portions 18a and 18b. 4 is generated in the same manner, the first to fourth sensing electrode portions 19a, 19b, 20a, and 20b are provided with the first and second driving electrode portions 17a and 17b and the first and second sensing electrode portions 18a and 18b. It is also possible to arrange the second arm 4.

上記構成により、互いに直交したＸ軸、Ｙ軸、Ｚ軸において、検出素子１の第１アーム２をＸ軸方向に配置して、第２アーム４をＹ軸方向に配置した場合、第１、第２駆動電極部１７ａ，１７ｂに共振周波数の交流電圧を印加すると、第１、第２駆動電極部１７ａ，１７ｂが配置された第２アーム４を起点に第２アーム４が駆動振動し、それに伴って錘部も第２アーム４のＸ軸方向に駆動振動する。   With the above configuration, when the first arm 2 of the detection element 1 is arranged in the X-axis direction and the second arm 4 is arranged in the Y-axis direction on the X axis, the Y axis, and the Z axis orthogonal to each other, When an AC voltage having a resonance frequency is applied to the second drive electrode portions 17a and 17b, the second arm 4 is driven to vibrate starting from the second arm 4 on which the first and second drive electrode portions 17a and 17b are arranged. Along with this, the weight portion also vibrates in the X-axis direction of the second arm 4.

このとき、Ｚ軸周りに角速度が生じた場合、錘部１１の駆動振動と同調して、錘部１１には駆動振動方向と直交した方向にコリオリ力が発生するので、第２アーム４にＺ軸周りの角速度に起因した歪を発生させることができ、この歪を検出することにより角速度を検出できる。よって、検出素子１をＺ軸方向に立設せずに伏せた状態で、Ｚ軸周りの角速度を検出でき、低背化を図れる。   At this time, when an angular velocity is generated around the Z axis, Coriolis force is generated in the weight portion 11 in a direction orthogonal to the drive vibration direction in synchronization with the drive vibration of the weight portion 11. Distortion caused by the angular velocity around the axis can be generated, and the angular velocity can be detected by detecting this distortion. Therefore, the angular velocity around the Z axis can be detected with the detection element 1 lying down without standing in the Z axis direction, and the height can be reduced.

特に、互いに直交するＸ軸、Ｙ軸、Ｚ軸において、錘部１１をＸ軸方向に駆動振動させるように固定部９をＸＹ平面に配置した場合、錘部１１のＸ軸方向への共振周波数と錘部１１のＹ軸方向への共振周波数とを異ならせているので、錘部１１を的確にＸ軸方向へ駆動振動させることができる。Ｘ軸方向への共振周波数とＹ軸方向への共振周波数とが等しい場合は、Ｘ軸方向へ駆動振動させようとしてもＺ軸方向にも変位して、駆動振動方向が安定せず、角速度の検出ができない恐れがある。   In particular, when the fixed portion 9 is arranged on the XY plane so as to drive and vibrate the weight portion 11 in the X-axis direction on the X, Y, and Z axes orthogonal to each other, the resonance frequency of the weight portion 11 in the X-axis direction. Since the resonance frequency of the weight portion 11 in the Y-axis direction is different, the weight portion 11 can be accurately driven and vibrated in the X-axis direction. When the resonance frequency in the X-axis direction and the resonance frequency in the Y-axis direction are equal, the drive vibration direction in the X-axis direction is displaced in the Z-axis direction, the drive vibration direction is not stable, and the angular velocity There is a possibility that it cannot be detected.

なお、第２アーム４の幅を大きくすると錘部１１のＸ軸方向への共振周波数とＹ軸方向への共振周波数との周波数差が小さくなり、第２アーム４の幅を小さくすると錘部１１のＸ軸方向への共振周波数とＹ軸方向への共振周波数との周波数差が大きくなる。この周波数差が大きくなりすぎると感度が低下するので、周波数差は１００〜５００Ｈｚになるようにするのが望ましい。   When the width of the second arm 4 is increased, the frequency difference between the resonance frequency in the X-axis direction and the resonance frequency in the Y-axis direction of the weight portion 11 is decreased, and when the width of the second arm 4 is decreased, the weight portion 11. The frequency difference between the resonance frequency in the X-axis direction and the resonance frequency in the Y-axis direction becomes large. If this frequency difference becomes too large, the sensitivity decreases, so it is desirable that the frequency difference be 100 to 500 Hz.

本発明に係る角速度センサは、Ｚ軸周りの角速度を検出する場合でも低背化が可能なので各種電子機器の小型化が図れ、各種電子機器に適用できるものである。   The angular velocity sensor according to the present invention can be reduced in height even when detecting an angular velocity around the Z-axis, so that various electronic devices can be miniaturized and applied to various electronic devices.

本発明の一実施の形態における角速度センサの検出素子の斜視図The perspective view of the detection element of the angular velocity sensor in one embodiment of this invention 図１のＡ−Ａ断面図AA sectional view of FIG. 同角速度センサの動作状態図Operation state diagram of the same angular velocity sensor 従来の角速度センサの検出素子の斜視図The perspective view of the detection element of the conventional angular velocity sensor 図４のＡ−Ａ断面図AA sectional view of FIG.

符号の説明Explanation of symbols

１ 検出素子
２ 第１アーム
４ 第２アーム
６ 支持部
９ 固定部
１１ 錘部
１３ 圧電体
１４ 下部電極
１５ 上部電極
１６ 対向部
１７ 第１駆動手段
１７ａ 第１駆動電極部
１７ｂ 第２駆動電極部
１８ 第１検知手段
１８ａ 第１検知電極部
１８ｂ 第２検知電極部
１９ 第１感知手段
１９ａ 第１感知電極部
１９ｂ 第２感知電極部
２０ 第２感知手段
２０ａ 第３感知電極部
２０ｂ 第４感知電極部
２１ａ 第１引き出し線
２１ｂ 第２引き出し線
２１ｃ 第３引き出し線
２１ｄ 第４引き出し線
２２ａ 第１引き出し線
２２ｂ 第２引き出し線
２２ｃ 第３引き出し線
２２ｄ 第４引き出し線 DESCRIPTION OF SYMBOLS 1 Detection element 2 1st arm 4 2nd arm 6 Support part 9 Fixing part 11 Weight part 13 Piezoelectric body 14 Lower electrode 15 Upper electrode 16 Opposing part 17 1st drive means 17a 1st drive electrode part 17b 2nd drive electrode part 18 First sensing means 18a First sensing electrode part 18b Second sensing electrode part 19 First sensing means 19a First sensing electrode part 19b Second sensing electrode part 20 Second sensing means 20a Third sensing electrode part 20b Fourth sensing electrode part 21a First leader line 21b Second leader line 21c Third leader line 21d Fourth leader line 22a First leader line 22b Second leader line 22c Third leader line 22d Fourth leader line

Claims (2)

第１アームを第２アームに略直交方向に連結して形成した２つの直交アームと、２つの前記第１アームの一端を支持した支持部と、前記第１アームの他端を連結するとともに実装基板に固定する固定部と、前記第２アームの先端部に連結した錘部と、前記錘部を駆動振動させる駆動手段とを有する検出素子を備え、
互いに直交するＸ軸、Ｙ軸、Ｚ軸において、前記錘部をＸ軸方向に駆動振動させるように前記固定部をＸＹ平面に配置した場合、前記錘部のＹ軸方向への共振周波数と前記錘部のＹ軸方向への共振周波数とを異ならせた角速度センサ。 Two orthogonal arms formed by connecting the first arm to the second arm in a substantially orthogonal direction, a support portion that supports one end of the two first arms, and the other end of the first arm are connected and mounted. A detecting element having a fixing part for fixing to the substrate, a weight part connected to a tip part of the second arm, and a driving means for driving and vibrating the weight part;
In the X axis, Y axis, and Z axis orthogonal to each other, when the fixed part is arranged on the XY plane so as to drive and vibrate the weight part in the X axis direction, the resonance frequency of the weight part in the Y axis direction and the An angular velocity sensor in which the resonance frequency of the weight portion in the Y-axis direction is made different. 前記第２アームは前記第２アーム自身と対向するまで折曲するとともに前記駆動手段により前記第２アームの対向方向に前記錘部を駆動振動させる請求項１記載の角速度センサ。 2. The angular velocity sensor according to claim 1, wherein the second arm bends until it faces the second arm itself and causes the weight portion to drive and vibrate in the facing direction of the second arm by the driving means.
JP2006307437A 2006-11-14 2006-11-14 Angular velocity sensor Pending JP2008122263A (en)

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Cited By (3)

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CN102292615A (en) * 2009-02-13 2011-12-21 松下电器产业株式会社 Inertial force sensor and detecting element used for same
JPWO2010092806A1 (en) * 2009-02-13 2012-08-16 パナソニック株式会社 Inertial force sensor and detection element used therefor
US8689630B2 (en) 2009-02-13 2014-04-08 Panasonic Corporation Inertial force sensor and detecting element used for same
JPWO2011093077A1 (en) * 2010-01-29 2013-05-30 パナソニック株式会社 Angular velocity sensor
US8991248B2 (en) 2010-01-29 2015-03-31 Panasonic Intellectual Property Management Co., Ltd. Angular velocity sensor
WO2012049825A1 (en) * 2010-10-15 2012-04-19 日立オートモティブシステムズ株式会社 Physical quantity detector
JPWO2012049825A1 (en) * 2010-10-15 2014-02-24 日立オートモティブシステムズ株式会社 Physical quantity detection device
US8659101B2 (en) 2010-10-15 2014-02-25 Hitachi Automotive Systems, Ltd. Physical quantity detector
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