JP2008286521A - Rotational speed detecting unit, and rotational speed sensor - Google Patents

Rotational speed detecting unit, and rotational speed sensor Download PDF

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JP2008286521A
JP2008286521A JP2007128848A JP2007128848A JP2008286521A JP 2008286521 A JP2008286521 A JP 2008286521A JP 2007128848 A JP2007128848 A JP 2007128848A JP 2007128848 A JP2007128848 A JP 2007128848A JP 2008286521 A JP2008286521 A JP 2008286521A
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rotational speed
idt electrode
piezoelectric substrate
detection unit
speed detection
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Kunihito Yamanaka
國人 山中
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Miyazaki Epson Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To obtain a means to achieve a rotational speed detecting unit that is small, low-profile and inexpensive by applying SAW device technology. <P>SOLUTION: The rotational speed detecting unit comprises a rotational speed sensing element having: a piezoelectric substrate in which a protrusion portion is formed almost in the center part of the one major surface and uniform thin portions are formed on the both sides; and an IDT electrode consisting of a pair of comb-shaped electrodes one of which is formed almost in the center part of the other major surface of the piezoelectric substrate and the other of which is formed near the both ends respectively, and a support substrate bonding and holding the protrusion portion of the rotational speed sensing element by an adhesive, wherein, the IDT electrode arranged almost in the center part is set as input, and the comb-shaped electrodes of the IDT electrode which are arranged near the both ends respectively and have different polarities are connected with each other in parallel and are set as output. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、回転速度検知ユニット及び回転速度センサに関し、特に回転速度による弾性表面波の周波数変化を利用した回転速度検知ユニット及び回転速度センサに関する。   The present invention relates to a rotational speed detection unit and a rotational speed sensor, and more particularly, to a rotational speed detection unit and a rotational speed sensor that use a frequency change of a surface acoustic wave due to the rotational speed.

回転速度検知ユニット、力検知ユニットは、従来からVTR、エンジン、モーター、自動車、航空機から各種プラントの異常振動監視等に、広く使用されている。
特許文献1には弾性表面波を利用した外力センサが開示されている。図16は外力センサの構成を示す正面図であり、圧電材料からなる長板状のビーム101が、基端部の表裏面を2個の直方体状の支持部108に挟まれ、片持ち梁状に接着されている。接着には接着性の弾性表面波吸収材107が用いられる。ビーム101は、先端部の両面を2個の直方体状の重り109に挟まれ、接着されている。重り109は外力を効率よく歪みに変換するためのものである。支持部108と重り109との間のビーム101の両面には、ビームを挟んで対向する位置に一対の送信用のIDT電極103が設けられている。送信用のIDT電極103と支持部108との間のビーム101の両面には、ビーム101を挟んで対向する位置に一対の受信用のIDT電極104が設けられている。
Conventionally, the rotational speed detection unit and the force detection unit are widely used for monitoring abnormal vibrations of various plants from VTRs, engines, motors, automobiles, and aircrafts.
Patent Document 1 discloses an external force sensor using surface acoustic waves. FIG. 16 is a front view showing the configuration of the external force sensor. A long plate-like beam 101 made of a piezoelectric material is sandwiched between two rectangular parallelepiped support portions 108 on the front and back surfaces of the base end portion, and is cantilevered. It is glued to. An adhesive surface acoustic wave absorber 107 is used for adhesion. The beam 101 is sandwiched and bonded by two rectangular parallelepiped weights 109 on both sides of the tip. The weight 109 is for efficiently converting external force into strain. On both surfaces of the beam 101 between the support unit 108 and the weight 109, a pair of IDT electrodes 103 for transmission are provided at positions facing each other across the beam. On both surfaces of the beam 101 between the transmission IDT electrode 103 and the support unit 108, a pair of reception IDT electrodes 104 are provided at positions facing each other with the beam 101 interposed therebetween.

受信用のIDT電極104は、夫々対応する増幅器105に接続され、各増幅器105は、夫々対応する送信用のIDT電極103及びオシレータ出力バッファアンプ113に接続されている。オシレータ出力バッファアンプ113は、ミキサー106に接続されている。一対の送信用のIDT電極103と、受信用のIDT電極104と、増幅器105とは、表裏一対の発振器を構成している。オシレータ出力バッファアンプ113は、表裏一対の発振器がミキサー106の負荷変動の影響を受けないようにするためのものである。   The reception IDT electrodes 104 are connected to the corresponding amplifiers 105, and each amplifier 105 is connected to the corresponding transmission IDT electrode 103 and the oscillator output buffer amplifier 113. The oscillator output buffer amplifier 113 is connected to the mixer 106. The pair of IDT electrodes 103 for transmission, the IDT electrode 104 for reception, and the amplifier 105 constitute a pair of front and back oscillators. The oscillator output buffer amplifier 113 is for preventing the pair of front and back oscillators from being affected by the load fluctuation of the mixer 106.

ビーム101の先端部に取り付けた重り109に外力102が作用すると、ビーム101の表面に歪みが発生する。この歪みは、ビーム101の表面を伝搬する弾性表面波の伝搬時間を変化させる。送信用のIDT電極103と受信用のIDT電極104との間の弾性表面波の伝搬時間が変化すると、IDT電極103と、IDT電極104と、増幅器105とで構成する発振器の発振周波数が変化する。ミキサー106が、表裏一対の発振器の発振周波数を信号処理して、差周波数成分を出力し、ゼロクロスコンパレータ114がこの出力を矩形波出力として取り出す。この出力を処理することにより外力102の大きさが求められる。
特開平2−228530号公報
When the external force 102 acts on the weight 109 attached to the tip of the beam 101, the surface of the beam 101 is distorted. This distortion changes the propagation time of the surface acoustic wave propagating on the surface of the beam 101. When the propagation time of the surface acoustic wave between the transmitting IDT electrode 103 and the receiving IDT electrode 104 changes, the oscillation frequency of the oscillator constituted by the IDT electrode 103, the IDT electrode 104, and the amplifier 105 changes. . The mixer 106 performs signal processing on the oscillation frequency of the pair of front and back oscillators and outputs a difference frequency component, and the zero-cross comparator 114 extracts this output as a rectangular wave output. By processing this output, the magnitude of the external force 102 is obtained.
JP-A-2-228530

しかしながら、従来の市販されている回転速度検知ユニットは、小型機器に用いるには大きすぎるという問題があり、また、特許文献1に開示されている外力センサのように、長板状のビーム101の表裏に送受信用夫々一対のIDT電極を形成すると、フォトリソグラフィ工程の工数が増大するという問題と、表裏に形成されるIDT電極のパターン精度が微妙に異なり、外力センサの測定精度を劣化させるという問題があった。
本発明は上記問題を解決するためになされたもので、圧電基板にIDT電極を形成し、回転速度を測定する小型、低背型、低コストの回転速度検知ユニットと回転速度センサを提供することにある。
However, the conventional commercially available rotational speed detection unit has a problem that it is too large for use in a small device, and, like the external force sensor disclosed in Patent Document 1, the long plate-like beam 101 has a problem. Forming a pair of IDT electrodes for transmission and reception on the front and back increases the man-hours of the photolithography process, and the problem that the pattern accuracy of the IDT electrodes formed on the front and back is slightly different, degrading the measurement accuracy of the external force sensor was there.
The present invention has been made to solve the above-mentioned problems, and provides a small, low-profile, low-cost rotational speed detection unit and rotational speed sensor for forming a rotational speed by forming an IDT electrode on a piezoelectric substrate. It is in.

本発明は、小型、低背型で低コストの回転速度検知ユニットと回転速度センサを得るため、一方の主面の略中央部に突起部を有すると共に該突起部の両側に均一な薄肉部を有した圧電基板と、前記圧電基板の他方の主面上の略中央部と両端部寄りに夫々少なくとも一個ずつ形成したIDT電極と、を有した回転速度感応素子と、前記回転速度感応素子の前記突起部を保持部材により固着保持する支持基板と、を備えた回転速度検知ユニットであって、前記略中央部に配置したIDT電極と、前記両端部寄り位置に夫々配置したIDT電極のうちの一方の端部寄り位置に配置したIDT電極との間の位相推移と、前記略中央部に配置したIDT電極と、前記両端部寄り位置に夫々配置したIDT電極のうちの他方の端部寄り位置に配置したIDT電極との間の位相推移と、が互いに180°異なっている回転速度検知ユニットを構成する。
以上のように構成すると、一方の主面上に3個のIDT電極を形成した圧電基板と、該圧電基板を支持する支持基板とで、回転速度に応じた電圧が発生する回転速度検知ユニットが構成できるので、SAWデバイスの製造技術が利用でき、小型、低背型、低コストのユニットが得られるという効果がある。
In order to obtain a small-sized, low-profile and low-cost rotational speed detection unit and rotational speed sensor, the present invention has a protrusion at a substantially central portion of one main surface and uniform thin portions on both sides of the protrusion. A rotational speed sensitive element comprising: a piezoelectric substrate having at least one IDT electrode formed on the other principal surface of the piezoelectric substrate, and at least one IDT electrode near both ends. A rotation speed detection unit including a support substrate that holds and holds the protrusion portion by a holding member, and one of the IDT electrode disposed at the substantially central portion and the IDT electrode disposed at positions near the both end portions. The phase transition between the IDT electrode disposed near the end of the IDT electrode, the IDT electrode disposed substantially at the center, and the position near the other end of the IDT electrodes disposed near the both ends. Placed ID Configuring the phase shift between the electrodes, a rotational speed detection unit but are different from each other by 180 °.
If comprised as mentioned above, the rotational speed detection unit which generate | occur | produces the voltage according to rotational speed with the piezoelectric substrate which formed three IDT electrodes on one main surface, and the support substrate which supports this piezoelectric substrate. Since it can be configured, the SAW device manufacturing technology can be used, and there is an effect that a small, low profile, and low cost unit can be obtained.

一方の主面の略中央部に突起部を有すると共に該突起部の両側に均一な薄肉部を有した圧電基板と、前記圧電基板の他方の主面上に形成された少なくとも2個のIDT電極と複数の反射器と、を有した回転速度感応素子と、前記回転速度感応素子の前記突起部を保持部材により固着保持する支持基板と、を備えた回転速度検知ユニットであって、前記圧電基板の一方の薄肉部には、少なくとも1個のIDT電極と、該IDT電極の両側に反射器とを配置し、前記圧電基板の他方の薄肉部には、少なくとも1個のIDT電極と、該IDT電極の両側に反射器とを配置した回転速度検知ユニットを構成する。
以上のように構成すると、一方の主面上に2個のSAW共振子を形成した圧電基板と、該圧電基板を支持する支持基板とで、回転速度に比例する周波数変化をもたらす回転速度検知ユニットが構成できるので、SAWデバイスの製造技術が利用でき、小型、低背型、低コストのユニットが得られるという効果がある。
A piezoelectric substrate having a protrusion at a substantially central portion of one main surface and a uniform thin portion on both sides of the protrusion, and at least two IDT electrodes formed on the other main surface of the piezoelectric substrate And a plurality of reflectors, and a rotation speed detecting unit, and a support substrate that holds and holds the protrusion of the rotation speed sensitive element by a holding member, wherein the piezoelectric substrate At least one IDT electrode and reflectors on both sides of the IDT electrode are arranged on one thin part of the piezoelectric substrate, and at least one IDT electrode and the IDT are arranged on the other thin part of the piezoelectric substrate. A rotational speed detection unit is configured in which reflectors are arranged on both sides of the electrode.
When configured as described above, a rotational speed detection unit that causes a frequency change proportional to the rotational speed between the piezoelectric substrate having two SAW resonators formed on one main surface and the support substrate that supports the piezoelectric substrate. Therefore, the SAW device manufacturing technology can be used, and there is an effect that a small, low profile, and low cost unit can be obtained.

一方の主面の略中央部に突起部を有すると共に該突起部の両側に均一な薄肉部を有した圧電基板と、前記圧電基板の他方の主面上に形成された少なくとも2個のIDT電極及び複数の反射器と、を有した回転速度感応素子と、前記回転速度感応素子の前記突起部を保持部材により固着保持する支持基板と、を備えた回転速度検知ユニットであって、前記圧電基板の一方の薄肉部には、少なくとも1個のIDT電極と、該IDT電極の外側に反射器を配置し、前記圧電基板の他方の薄肉部には、少なくとも1個のIDT電極と、該IDT電極の外側に反射器を配置し、前記夫々のIDT電極の内側に夫々反射器を近接配置した回転速度検知ユニットを構成する。
以上のように構成すると、一方の主面上に2個のSAW共振子を形成した圧電基板と、該圧電基板を支持する支持基板とで、回転速度に比例する周波数変化をもたらす回転速度検知ユニットが構成できるので、SAWデバイスの製造技術が利用でき、さらに小型で、低背型、低コストのユニットが得られるという効果がある。
A piezoelectric substrate having a protrusion at a substantially central portion of one main surface and a uniform thin portion on both sides of the protrusion, and at least two IDT electrodes formed on the other main surface of the piezoelectric substrate And a plurality of reflectors, and a rotation speed detecting unit, and a support substrate that holds and holds the protrusion of the rotation speed sensitive element by a holding member, wherein the piezoelectric substrate At least one IDT electrode and a reflector are disposed outside the IDT electrode, and at least one IDT electrode and the IDT electrode are disposed on the other thin part of the piezoelectric substrate. A rotational speed detection unit is configured in which reflectors are arranged outside the IDT and reflectors are arranged close to each inside the IDT electrodes.
When configured as described above, a rotational speed detection unit that causes a frequency change proportional to the rotational speed between the piezoelectric substrate having two SAW resonators formed on one main surface and the support substrate that supports the piezoelectric substrate. Therefore, it is possible to use the SAW device manufacturing technology, and to obtain a compact, low-profile and low-cost unit.

前記圧電基板の両薄肉部の一方の主面、又は/及び、他方の主面に重りとして金属膜を蒸着するか、金属フィラー接着剤又は金属部材を接着した上記の回転速度検知ユニットを構成する。
以上のように構成すると、上記の効果に加えて、回転速度検知の感度が改善されるという利点がある。
The rotational speed detection unit described above is formed by depositing a metal film as a weight on one main surface and / or the other main surface of both thin portions of the piezoelectric substrate or by adhering a metal filler adhesive or a metal member. .
When configured as described above, in addition to the above effects, there is an advantage that the sensitivity of rotation speed detection is improved.

一方の主面に所定の間隔を隔てて2個の凹陥部を形成することにより夫々形成した2個の均一な薄肉部を有すると共に略中央部及び両端部に夫々厚肉部を有した圧電基板と、該圧電基板の他方の主面上の略中央部と両端部寄りに夫々少なくとも一個ずつ形成したIDT電極と、を有した回転速度感応素子と、前記回転速度感応素子の前記略中央部の厚肉部を保持部材により固着保持する支持基板と、を備えた回転速度検知ユニットであって、前記略中央部に配置したIDT電極と、前記両端部寄り位置に夫々配置したIDT電極のうちの一方の端部寄り位置に配置したIDT電極との間の位相推移と、前記略中央部に配置したIDT電極と、前記両端部寄り位置に夫々配置したIDT電極のうちの他方の端部寄り位置に配置したIDT電極との間の位相推移と、が互いに180°異なっている回転速度検知ユニットを構成する。
以上のように構成すると、一方の主面上に3個のIDT電極を形成した圧電基板と、該圧電基板を支持する支持基板とで、回転速度に応じた電圧が発生する回転速度検知ユニットが構成できるので、SAWデバイスの製造技術が利用できる上、回転速度検知の感度が改善される小型、低背型、低コストのユニットが得られるという効果がある。
A piezoelectric substrate having two uniform thin portions each formed by forming two recessed portions at a predetermined interval on one main surface, and having thick portions at substantially the center and both ends. A rotational speed sensing element having at least one IDT electrode formed on the other main surface of the piezoelectric substrate and at least one IDT electrode near both ends, and the substantially central part of the rotational speed sensing element. A rotational speed detection unit comprising a support substrate for fixing and holding a thick portion by a holding member, and an IDT electrode disposed at the substantially central portion and an IDT electrode disposed at a position closer to both ends. Phase transition between the IDT electrode disposed at one end portion position, the IDT electrode disposed at the substantially central portion, and the other end portion position among the IDT electrodes disposed at the both end portion positions. IDT electrode arranged in And phase shift between, but constitutes a rotational speed detection unit which are different from each other by 180 °.
If comprised as mentioned above, the rotational speed detection unit which generate | occur | produces the voltage according to rotational speed with the piezoelectric substrate which formed three IDT electrodes on one main surface, and the support substrate which supports this piezoelectric substrate. Since it can be configured, it is possible to use a SAW device manufacturing technique and to obtain a small, low-profile, low-cost unit that improves the sensitivity of rotational speed detection.

一方の主面に所定の間隔を隔てて2個の凹陥部を形成することにより夫々形成した2個の薄肉部を有すると共に中央部及び両端部に夫々厚肉部を有した圧電基板と、該圧電基板の他方の主面上に少なくとも2個のIDT電極と複数の反射器とを有した回転速度感応素子と、前記回転速度感応素子の前記突起部を保持部材により固着保持する支持基板と、を備えた回転速度検知ユニットであって、前記圧電基板の一方の薄肉部には、少なくとも1個のIDT電極と、該IDT電極の両側に反射器を配置し、前記圧電基板の他方の薄肉部には、少なくとも1個のIDT電極と、該IDT電極の両側に夫々形成した反射器を配置した回転速度検知ユニットを構成する。
以上のように構成すると、一方の主面上に2個のSAW共振子を形成した圧電基板と、該圧電基板を支持する支持基板とで、回転速度に比例する周波数変化をもたらす回転速度検知ユニットが構成できるので、SAWデバイスの製造技術が利用でき、回転速度検知の感度が改善された小型、低背型、低コストのユニットが得られるという効果がある。
A piezoelectric substrate having two thin portions formed by forming two recessed portions at a predetermined interval on one main surface and having thick portions at the center and both ends, A rotational speed sensitive element having at least two IDT electrodes and a plurality of reflectors on the other main surface of the piezoelectric substrate; a support substrate for fixing and holding the protrusion of the rotational speed sensitive element by a holding member; A rotational speed detection unit comprising: at least one IDT electrode on one thin portion of the piezoelectric substrate, and reflectors on both sides of the IDT electrode, and the other thin portion of the piezoelectric substrate. Includes a rotational speed detection unit in which at least one IDT electrode and reflectors formed on both sides of the IDT electrode are arranged.
When configured as described above, a rotational speed detection unit that causes a frequency change proportional to the rotational speed between the piezoelectric substrate having two SAW resonators formed on one main surface and the support substrate that supports the piezoelectric substrate. Therefore, it is possible to use a SAW device manufacturing technique and to obtain a small, low-profile, low-cost unit with improved rotational speed detection sensitivity.

一方の主面に所定の間隔を隔てて2個の凹陥部を形成することにより夫々形成した2個の薄肉部を有すると共に中央部及び両端部に夫々厚肉部を有した圧電基板と、該圧電基板の他方の主面上に少なくとも2個のIDT電極と複数の反射器とを有した回転速度感応素子と、前記回転速度感応素子の前記突起部を保持部材により固着保持する支持基板と、を備えた回転速度検知ユニットであって、前記圧電基板の一方の薄肉部には、少なくとも1個のIDT電極と、該IDT電極の外側に反射器を配置し、前記圧電基板の他方の薄肉部には、少なくとも1個のIDT電極と、該IDT電極の外側に反射器を配置し、前記夫々のIDT電極の圧電基板中央寄りに近接して反射器を配置した回転速度検知ユニットを構成する。
以上のように構成すると、一方の主面上に2個のSAW共振子を形成した圧電基板と、該圧電基板を支持する支持基板とで、回転速度に比例する周波数変化をもたらす回転速度検知ユニットが構成できるので、SAWデバイスの製造技術が利用でき、回転速度検知の感度が改善され、さらに小型で、低背型、低コストのユニットが得られるという効果がある。
A piezoelectric substrate having two thin portions formed by forming two recessed portions at a predetermined interval on one main surface and having thick portions at the center and both ends, A rotational speed sensitive element having at least two IDT electrodes and a plurality of reflectors on the other main surface of the piezoelectric substrate; a support substrate for fixing and holding the protrusion of the rotational speed sensitive element by a holding member; A rotational speed detection unit comprising: at least one IDT electrode on one thin portion of the piezoelectric substrate; and a reflector on the outside of the IDT electrode, and the other thin portion of the piezoelectric substrate. Comprises a rotational speed detection unit in which at least one IDT electrode and a reflector are arranged outside the IDT electrode, and a reflector is arranged close to the center of the piezoelectric substrate of each IDT electrode.
When configured as described above, a rotational speed detection unit that causes a frequency change proportional to the rotational speed between the piezoelectric substrate having two SAW resonators formed on one main surface and the support substrate that supports the piezoelectric substrate. Therefore, the SAW device manufacturing technology can be used, the rotational speed detection sensitivity can be improved, and a small, low-profile, low-cost unit can be obtained.

上記の回転速度検知ユニットと、発振回路と、信号処理回路と、を備えた回転速度センサを構成する。
以上のように構成すると、SAWデバイスの製造技術が利用でき、小型で、低背型、低コストの回転速度センサが得られるという効果がある。
A rotational speed sensor including the rotational speed detection unit, an oscillation circuit, and a signal processing circuit is configured.
When configured as described above, the SAW device manufacturing technology can be used, and there is an effect that a small, low-profile, low-cost rotational speed sensor can be obtained.

以下、本発明の実施の形態を図面に基づいて詳細に説明する。図1は、本発明の一実施形態としての回転速度検知ユニットの構成例を示す図であり、同図(a)は平面図、同図(b)はQ−Qにおける断面図である。
本発明に係る回転速度検知ユニット1は、一方の主面(下面)の略中央部に突起部6aを有すると共に、突起部6aの両側に形成された均一な薄肉部6bを有した圧電基板6と、圧電基板6の他方の主面(上面)上の略中央部と両端部寄り位置とに、夫々一個ずつ形成した一対の櫛形電極からなるIDT電極10、11、12と、を有した回転速度感応素子Sと、回転速度感応素子Sの突起部6aを接着剤(図示せず)により接着保持する支持基板Pと、を備えている。略中央部に配置したIDT電極10と、両端部寄り位置に夫々配置したIDT電極のうちの一方の端部寄り位置に配置したIDT電極11との間の位相推移と、略中央部に配置したIDT電極10と、両端部寄り位置に夫々配置したIDT電極のうちの他方の端部寄り位置に配置したIDT電極12との間の位相推移と、が互いに180°異なるようにする。IDT電極10を入力、又は出力とし、IDT電極11、12を並列接続して出力、又は入力として回転速度検知ユニット1を構成する。
図1において、中央部のIDT電極10の電極指の本数が偶数本である場合には、両端部寄りのIDT電極11、12を、IDT電極10の中心軸に対して線対称に配置し、IDT電極10の電極指の本数が奇数本である場合には、IDT電極10の中心軸に対して点対称に配置すれば、IDT電極11、12の位相差が180°となる。なお、圧電基板の主表面の両端部には音波吸収材20を塗布してある。
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration example of a rotation speed detection unit as an embodiment of the present invention, where FIG. 1 (a) is a plan view and FIG. 1 (b) is a cross-sectional view at QQ.
The rotational speed detection unit 1 according to the present invention has a protruding portion 6a at a substantially central portion of one main surface (lower surface), and a piezoelectric substrate 6 having a uniform thin portion 6b formed on both sides of the protruding portion 6a. And IDT electrodes 10, 11, 12 made of a pair of comb-shaped electrodes formed one by one on the other principal surface (upper surface) of the piezoelectric substrate 6 at a position near the center and both ends. A speed-sensitive element S and a support substrate P that holds the protrusion 6a of the rotational speed-sensitive element S by an adhesive (not shown) are provided. Phase transition between the IDT electrode 10 disposed in the substantially central portion and the IDT electrode 11 disposed in the position closer to one end of the IDT electrodes disposed in the positions closer to both ends, and disposed in the substantially central portion. The phase transition between the IDT electrode 10 and the IDT electrode 12 disposed near the other end of the IDT electrodes disposed near the both ends is set to be 180 ° different from each other. The IDT electrode 10 is used as an input or output, and the IDT electrodes 11 and 12 are connected in parallel to form the rotational speed detection unit 1 as an output or input.
In FIG. 1, when the number of electrode fingers of the IDT electrode 10 at the center is an even number, the IDT electrodes 11 and 12 near both ends are arranged symmetrically with respect to the central axis of the IDT electrode 10, When the number of electrode fingers of the IDT electrode 10 is an odd number, the phase difference between the IDT electrodes 11 and 12 is 180 ° if they are arranged point-symmetrically with respect to the central axis of the IDT electrode 10. A sound absorbing material 20 is applied to both ends of the main surface of the piezoelectric substrate.

各IDT電極10、11、12は、互いに間挿し合う一対の電極指からなり、その電極材料はアルミニウム合金等を用いる。IDT電極10の中心部と、IDT電極11、12夫々の中心部との距離L1、L2は等しくする。図1(a)に示すように、IDT電極10の一方(下側)のバスバーと、IDT電極11、12の他方(上側)のバスバーと、をリード電極にて接続し、IDT電極11、12夫々の一方(下側)のバスバーと、圧電基板6上に形成したボンディングパッド16と、をリード電極にて接続する。更に、IDT電極10の他方(上側)のバスバー及び一方(下側)のバスバーを支持基板P上の端子電極30、31に夫々ボンディングワイヤにて接続し、ボンディングパッド16と、支持基板P上の端子電極32とをボンディングワイヤにて接続して回転速度検知ユニット1を構成する。なお、端子電極31は接地する。
また、上記の説明では、圧電基板6の主面上の略中央部と両端部寄りに、夫々一個ずつのIDT電極を配した例を説明したが、夫々複数個のIDT電極を配してもよい。また、突起部6aと支持基板Pとを接着剤により接着保持すると説明したが、半田バンプ、金バンプ、ガラス材等でもよい。
Each IDT electrode 10, 11, 12 is composed of a pair of electrode fingers that are interleaved with each other, and an aluminum alloy or the like is used as the electrode material. The distances L1 and L2 between the center portion of the IDT electrode 10 and the center portions of the IDT electrodes 11 and 12 are made equal. As shown in FIG. 1A, one (lower) bus bar of the IDT electrode 10 and the other (upper) bus bar of the IDT electrodes 11 and 12 are connected by lead electrodes, and the IDT electrodes 11 and 12 are connected. Each one (lower) bus bar and the bonding pad 16 formed on the piezoelectric substrate 6 are connected by lead electrodes. Further, the other (upper) bus bar and one (lower) bus bar of the IDT electrode 10 are connected to the terminal electrodes 30 and 31 on the support substrate P by bonding wires, respectively, and the bonding pad 16 and the support substrate P on the support substrate P are connected. The rotational speed detection unit 1 is configured by connecting the terminal electrode 32 with a bonding wire. The terminal electrode 31 is grounded.
In the above description, an example is described in which one IDT electrode is arranged near the center and both ends on the main surface of the piezoelectric substrate 6, but a plurality of IDT electrodes may be arranged. Good. Moreover, although it demonstrated that the projection part 6a and the support substrate P were adhere | attached and hold | maintained with the adhesive agent, a solder bump, a gold bump, a glass material etc. may be sufficient.

図2は、支持基板Pとしてセラミックパッケージを用いた例であって、セラミックパッケージの凹陥部の底部に、図1(a)に示す回転速度感応素子Sの裏面に形成した突起部6aを接着剤を用いて接着し、各IDT電極のバスバー及びボンディングパッドと、セラミックパッケージの周縁部に形成した端子電極30〜32と、をボンディングワイヤ35にて接続して、回転速度検知ユニット1を構成した例である。セラミックパッケージの内部の四隅の周縁部に形成した端子電極を中心部に対して傾斜して形成しているため、大きな圧電基板を収容することができる。   FIG. 2 shows an example in which a ceramic package is used as the support substrate P, and a protrusion 6a formed on the back surface of the rotational speed sensing element S shown in FIG. The rotational speed detection unit 1 is configured by connecting the bus bars and bonding pads of the IDT electrodes and the terminal electrodes 30 to 32 formed on the peripheral edge of the ceramic package with bonding wires 35. It is. Since the terminal electrodes formed at the peripheral edge portions of the four corners inside the ceramic package are formed to be inclined with respect to the central portion, a large piezoelectric substrate can be accommodated.

図1に示した回転速度検知ユニット1の動作について図3に示したIDT電極10、11、12を用いて説明する。各IDT電極11、12の電極パターンは同一とし、IDT電極10の中心部から各IDT電極11、12の夫々の中心部までの距離L1、L2を共に等しく設定する。IDT電極11、12の電極パターンが同じであるため、一方のIDT電極11は最内側の電極指から外側の電極指へと、下側のバスバー、上側のバスバーと交互に接続される。他方のIDT電極12は最内側の電極指から外側の電極指へと、上側のバスバー、下側のバスバーと交互に接続されている。つまり、中央部のIDT電極10からみると、両サイドのIDT電極11、12の電極指のバスバーへの接続順が異なっている。   The operation of the rotation speed detection unit 1 shown in FIG. 1 will be described using the IDT electrodes 10, 11, and 12 shown in FIG. The electrode patterns of the IDT electrodes 11 and 12 are the same, and the distances L1 and L2 from the central portion of the IDT electrode 10 to the central portions of the IDT electrodes 11 and 12 are both set equal. Since the electrode patterns of the IDT electrodes 11 and 12 are the same, one IDT electrode 11 is alternately connected from the innermost electrode finger to the outer electrode finger with the lower bus bar and the upper bus bar. The other IDT electrode 12 is alternately connected with the upper bus bar and the lower bus bar from the innermost electrode finger to the outer electrode finger. That is, when viewed from the IDT electrode 10 in the center, the order of connection of the electrode fingers of the IDT electrodes 11 and 12 on both sides to the bus bar is different.

初めに回転速度検知ユニット1が静止状態にある場合について説明する。IDT電極10に高周波電圧を加えて弾性表面波を励起すると、該弾性表面波は圧電基板(図示せず)上を左右に同じ伝搬速度で進行し、IDT電極11、12に到達して、各電極指上に電荷を生じさせる。図3はある瞬間の電荷の発生状態を図示したもので、IDT電極11、12の夫々の内側の電極指から、符号+、−、+、−で示す電荷が発生する。IDT電極11、12の夫々の下側の櫛形電極を接続し、夫々の上側の櫛形電極を共に接地して並列接続する。IDT電極11、12の夫々の下側の櫛形電極には互いに逆極性の電荷が発生しているので、並列接続すると発生した電荷は打ち消され、出力端子OUTには電荷(電圧)は生じない。ただ、IDT電極10の中心部からIDT電極11、12の夫々の中心部までの距離L1、L2の僅かの誤差、IDT電極11、12の電極パターンのエッチング誤差、圧電基板の加工誤差等により僅かの出力電圧が発生する。   First, the case where the rotational speed detection unit 1 is in a stationary state will be described. When a high frequency voltage is applied to the IDT electrode 10 to excite the surface acoustic wave, the surface acoustic wave travels left and right on the piezoelectric substrate (not shown) at the same propagation speed, reaches the IDT electrodes 11 and 12, Electric charges are generated on the electrode fingers. FIG. 3 illustrates the state of charge generation at a certain moment. Charges indicated by signs +, −, +, and − are generated from the electrode fingers inside the IDT electrodes 11 and 12, respectively. The lower comb electrodes of the IDT electrodes 11 and 12 are connected, and the upper comb electrodes are grounded together and connected in parallel. Since charges having opposite polarities are generated in the comb electrodes on the lower side of the IDT electrodes 11 and 12, the generated charges are canceled when connected in parallel, and no charge (voltage) is generated in the output terminal OUT. However, the difference is slightly due to slight errors in the distances L1 and L2 from the central portion of the IDT electrode 10 to the central portions of the IDT electrodes 11 and 12, the etching error of the electrode pattern of the IDT electrodes 11 and 12, the processing error of the piezoelectric substrate, etc. Output voltage is generated.

次に、図4(a)は回転速度検知ユニット1の中心部の回りに回転力が加えられた状態を示した正面図であり、支持基板Pは省略している。図4(a)に示すように、回転速度検知ユニット1の圧電基板6の両端部の回転方向への変位が慣性によって遅延し、回転方向と反対方向に変形する。薄肉部6bが図4(a)に示すように変形すると、左側の薄肉部6bに伸張歪みが、右側の薄肉部6bには圧縮歪みが生じ、弾性表面波の左右への伝搬速度が互いに異なってくる。これに加え、距離L1は伸び、距離L2縮むことになる。この2つの現象でIDT電極11、12に発生する電荷の発生状態は、静止の場合とは異なり、出力OUTに電荷(電圧)が発生することになる。出力OUTに発生する電荷(電圧)の量(電圧の大きさ)は、角速度に応じて変化する。出力OUTに生じる電圧を測定することにより、回転速度検知ユニット1の回転速度を測定することができる。   Next, FIG. 4A is a front view showing a state in which a rotational force is applied around the central portion of the rotational speed detection unit 1, and the support substrate P is omitted. As shown in FIG. 4A, the displacement in the rotational direction of both ends of the piezoelectric substrate 6 of the rotational speed detection unit 1 is delayed by inertia and deformed in the direction opposite to the rotational direction. When the thin-walled portion 6b is deformed as shown in FIG. 4A, the left thin-walled portion 6b is stretched and the right-side thin-walled portion 6b is compressed, and the propagation speeds of the surface acoustic waves to the left and right are different from each other. Come. In addition to this, the distance L1 increases and the distance L2 decreases. Unlike the stationary state, the generation state of charges generated in the IDT electrodes 11 and 12 due to these two phenomena generates charges (voltage) at the output OUT. The amount (voltage magnitude) of electric charges (voltage) generated at the output OUT changes according to the angular velocity. By measuring the voltage generated at the output OUT, the rotational speed of the rotational speed detection unit 1 can be measured.

図5(a)は、静止状態の回転速度検知ユニット1の入力に高周波電圧を印加した場合の出力の周波数応答である。出力応答は極めて小さい。図5(b)は、回転速度検知ユニット1の入力に高周波電圧を印加した状態で、回転速度検知ユニット1に回転を加えた場合の周波数応答であり、出力応答は図(a)の場合に比べて極めて大きいことが分かる。この発生した電圧から回転速度を求める。   FIG. 5A shows an output frequency response when a high frequency voltage is applied to the input of the rotational speed detection unit 1 in a stationary state. The output response is very small. FIG. 5B shows a frequency response when rotation is applied to the rotation speed detection unit 1 with a high frequency voltage applied to the input of the rotation speed detection unit 1, and the output response is as shown in FIG. It can be seen that it is extremely large. The rotational speed is obtained from the generated voltage.

図6は、回転速度検知ユニット1の入力に高周波電圧を印加した状態で、回転速度検知ユニット1に垂直方向の外力が、加えられた場合の薄肉部6bの変形を示した図である。左右両端部に位置する薄肉部6bは共に外力とは逆方向に変形し、左右の薄肉部6bには共に伸張歪みが生じる。この場合、IDT電極11、12の夫々の内側の電極指から外側の電極指に向けて順に+、−、+、−の電荷が発生し、下側の櫛形電極が並列接続された各IDT電極11、12において電荷は互いに打ち消され、出力部には電荷(電圧)は発生しない。   FIG. 6 is a view showing a deformation of the thin portion 6b when an external force in the vertical direction is applied to the rotational speed detection unit 1 in a state where a high frequency voltage is applied to the input of the rotational speed detection unit 1. FIG. The thin portions 6b located at the left and right ends are both deformed in the direction opposite to the external force, and both the left and right thin portions 6b are stretched. In this case, each of the IDT electrodes 11, 12 is charged with +, −, +, − charges in order from the inner electrode finger to the outer electrode finger, and the lower comb electrodes are connected in parallel. In 11 and 12, the charges cancel each other, and no charge (voltage) is generated in the output section.

図7は、回転速度検知ユニットの第2の実施例の構成を示した図であり、IDT電極10、11、12の構成のみを示す図である。圧電基板6、支持基板P等は図1と同様に構成する。IDT電極11、12はIDT電極10からみて対称に配置されており、一方のIDT電極11の一方(下側)のバスバーを接地し、他方のIDT電極12の他方の(上側)のバスバーを接地し、IDT電極11の他方の(上側)のバスバーとIDT電極12の一方(下側)のバスバーを接続して、IDT電極11、12を並列接続する。図7に示す第2の実施例の回転速度検知ユニットのIDT電極10に高周波電圧を印加すると、IDT電極11の上側の櫛形電極と、IDT電極12の下側の櫛形電極に発生する電荷は逆極性となり、並列接続した出力OUTの電圧は零となる。この第2の実施例の回転速度検知ユニットに回転を加えた場合の動作は、図4で説明した通りであるので説明は省略する。   FIG. 7 is a diagram showing the configuration of the second embodiment of the rotational speed detection unit, and is a diagram showing only the configuration of the IDT electrodes 10, 11, and 12. The piezoelectric substrate 6 and the support substrate P are configured in the same manner as in FIG. The IDT electrodes 11 and 12 are arranged symmetrically with respect to the IDT electrode 10, and one (lower) bus bar of one IDT electrode 11 is grounded, and the other (upper) bus bar of the other IDT electrode 12 is grounded. Then, the other (upper) bus bar of the IDT electrode 11 and one (lower) bus bar of the IDT electrode 12 are connected, and the IDT electrodes 11 and 12 are connected in parallel. When a high frequency voltage is applied to the IDT electrode 10 of the rotational speed detection unit of the second embodiment shown in FIG. 7, the charges generated in the comb electrode above the IDT electrode 11 and the comb electrode below the IDT electrode 12 are reversed. The polarity of the output OUT connected in parallel is zero. Since the operation when the rotation speed detection unit of the second embodiment is rotated is as described with reference to FIG.

図8は、回転速度検知ユニットの出力側に発生する電圧から、加えられた回転速度の大きさを求める処理方法の一例を示した図である。回転速度検知ユニットの入力側に、(a)の高周波電圧信号が入力されると、出力側から回転速度に応じて、(b)の出力電圧が得られる。この出力電圧を全波整流すると、(c)の波形の電圧が得られる。この電圧を(d)の積分回路に入力すると、(e)に示す直流電圧が得られる。この直流電圧の大きさから加えられた回転速度の大きさを求める。   FIG. 8 is a diagram showing an example of a processing method for obtaining the magnitude of the applied rotation speed from the voltage generated on the output side of the rotation speed detection unit. When the high-frequency voltage signal (a) is input to the input side of the rotational speed detection unit, the output voltage (b) is obtained from the output side according to the rotational speed. When this output voltage is full-wave rectified, a voltage having a waveform (c) is obtained. When this voltage is input to the integration circuit of (d), a DC voltage shown in (e) is obtained. The magnitude of the rotational speed applied is determined from the magnitude of the DC voltage.

図9は、回転速度検知ユニットの第3の実施例の構成を示す図であって、同図(a)は平面図、同図(b)はQ−Qにおける断面図である。回転速度検知ユニット2は、一方の主面の略中央部に突起部6aとその両側に均一な薄肉部6bとを形成した圧電基板6と、該圧電基板6の他方の主面上に2個のIDT電極13、14と複数の反射器15と、を有した回転速度感応素子Sと、該回転速度感応素子Sの突起部6aを接着剤(図示せず)により接着保持する支持基板Pと、を備えた回転速度検知ユニット2である。圧電基板6の一方の左側の薄肉部6bに、一方のIDT電極13とその両側に近接して反射器15と、を配置し、他方の右側の薄肉部6bに、他方のIDT電極14とその両側に近接して反射器15と、を配置して回転速度検知ユニット2を構成する。
以上の説明では、圧電基板6の左右の薄肉部6bに、夫々1個のIDT電極とその両側に反射器を配置した場合を説明したが、左右の薄肉部6bに複数のIDT電極を配置してもよい。また、突起部6aと支持基板Pとを接着剤により接着保持すると説明したが、半田バンプ、金バンプ、ガラス材等でもよい。
FIG. 9 is a diagram showing a configuration of a third embodiment of the rotational speed detection unit, where FIG. 9A is a plan view and FIG. 9B is a cross-sectional view taken along QQ. The rotational speed detection unit 2 includes two piezoelectric substrates 6 formed with a protrusion 6a at a substantially central portion of one main surface and a uniform thin portion 6b on both sides thereof, on the other main surface of the piezoelectric substrate 6. A rotation speed sensitive element S having IDT electrodes 13 and 14 and a plurality of reflectors 15; and a support substrate P that holds the protrusion 6a of the rotation speed sensitive element S by an adhesive (not shown). , A rotation speed detection unit 2. One IDT electrode 13 and a reflector 15 are disposed adjacent to both sides of the thin-walled portion 6b on one left side of the piezoelectric substrate 6, and the other IDT electrode 14 and its side are disposed on the other thin-walled portion 6b on the right side. The rotational speed detection unit 2 is configured by arranging the reflectors 15 adjacent to both sides.
In the above description, the case where one IDT electrode and reflectors are disposed on the left and right thin portions 6b of the piezoelectric substrate 6 has been described. However, a plurality of IDT electrodes are disposed on the left and right thin portions 6b. May be. Moreover, although it demonstrated that the projection part 6a and the support substrate P were adhere | attached and hold | maintained with the adhesive agent, a solder bump, a gold bump, a glass material etc. may be sufficient.

IDT電極13の上、下に設けた2個のボンディングパッドと、支持基盤Pに形成した端子電極30、31とをボンディングワイヤで接続し、IDT電極14の上、下に設けた2個のボンディングパッドと、支持基盤Pに形成した端子電極32、33とをボンディングワイヤで接続する。圧電基板6の左側に配置したIDT電極13とその両側の反射器15とでSAW共振子S1を構成し、圧電基板6の右側に配置したIDT電極14とその両側の反射器15とでSAW共振子S2を構成する。そして、SAW共振子S1、S2は、夫々発振回路(図示せず)に接続されている。図9に示す回転速度検知ユニット2の動作について説明する。初めに、回転速度検知ユニット2が静止状態にある場合は、SAW共振子S1、S2は、夫々f1、f2の周波数で発振しているものとする。   Two bonding pads provided above and below the IDT electrode 13 and terminal electrodes 30 and 31 formed on the support substrate P are connected by bonding wires, and two bonding pads provided above and below the IDT electrode 14 are connected. The pads and the terminal electrodes 32 and 33 formed on the support base P are connected by bonding wires. The SAW resonator S1 is formed by the IDT electrode 13 disposed on the left side of the piezoelectric substrate 6 and the reflectors 15 on both sides thereof, and the SAW resonance is formed by the IDT electrode 14 disposed on the right side of the piezoelectric substrate 6 and the reflectors 15 on both sides thereof. Construct child S2. The SAW resonators S1 and S2 are each connected to an oscillation circuit (not shown). The operation of the rotation speed detection unit 2 shown in FIG. 9 will be described. First, when the rotation speed detection unit 2 is in a stationary state, it is assumed that the SAW resonators S1 and S2 oscillate at frequencies f1 and f2, respectively.

次に、図9に示す回転速度検知ユニット2の中心の回りに回転が加えられた状態は、図4に示した正面図と同様である。図4と同様に、回転速度検知ユニット2の中心部を一方向へ回転させた際に両端部に位置する薄肉部6bの回転方向への変位が慣性によって遅れ、回転方向と反対方向に変形する。薄肉部6bが図4に示すように変形すると、左側の薄肉部6bに伸張歪みが、右側の薄肉部6bには圧縮歪みが夫々生じ、弾性表面波の左右への伝搬速度が互いに異なってくる。これに加え、左側の薄肉部6bは伸び、右側の薄肉部6bは縮むことになる。薄肉部6bに伸張、圧縮歪み、あるいは伸び、縮みが生じると弾性表面波の伝搬速度、伝搬時間が変化し、SAW共振子S1、S2の共振周波数が変化し、発振周波数がf’1、f’2に変化する。SAW共振子S1、S2の共振周波数の夫々の周波数の変化量(f1−f’1)、(f2−f’2)は、回転速度検知ユニット2に加えられた回転速度に概ね比例する。なお、左右の薄肉部6bに掛かる歪みは、伸張歪み、圧縮歪みと互いに逆の歪みであるため、周波数差(f1−f’1)、(f2−f’2)の符号は逆の符号となる。   Next, the state where the rotation is applied around the center of the rotation speed detection unit 2 shown in FIG. 9 is the same as the front view shown in FIG. As in FIG. 4, when the central portion of the rotational speed detection unit 2 is rotated in one direction, the displacement of the thin portions 6b located at both ends in the rotational direction is delayed by inertia and deforms in the direction opposite to the rotational direction. . When the thin-walled portion 6b is deformed as shown in FIG. 4, a tensile strain is generated in the left-side thin portion 6b and a compressive strain is generated in the right-side thin-walled portion 6b, and the propagation speeds of the surface acoustic waves to the left and right are different from each other. . In addition to this, the left thin portion 6b extends and the right thin portion 6b contracts. When the thin portion 6b is stretched, compressed, or stretched or contracted, the propagation speed and propagation time of the surface acoustic wave are changed, the resonant frequencies of the SAW resonators S1 and S2 are changed, and the oscillation frequency is f′1, f Change to '2. The change amounts (f1-f'1) and (f2-f'2) of the resonance frequencies of the SAW resonators S1 and S2 are approximately proportional to the rotational speed applied to the rotational speed detection unit 2. Since the distortion applied to the left and right thin portions 6b is opposite to the expansion distortion and the compression distortion, the signs of the frequency differences (f1-f'1) and (f2-f'2) are the opposite signs. Become.

図10は、回転速度検知ユニットの第4の実施例の構成を示す図であって、同図(a)は平面図、同図(b)はQ−Qにおける断面図である。回転速度検知ユニット2は、一方の主面の略中央部に突起部6aとその両側に均一厚の薄肉部6bとを形成した圧電基板6と、圧電基板6の他方の主面上に2個のIDT電極13、14と複数の反射器15と、を有した回転速度感応素子Sと、該回転速度感応素子Sの突起部6aを接着剤(図示せず)により接着保持する支持基板Pと、を備えている。圧電基板6の一方の左側の薄肉部6bにIDT電極13を配置すると共に、IDT電極3の外側に1個の反射器15を配置し、他方の右側の薄肉部6bに他方のIDT電極14を配置すると共に、IDT電極14の外側に1個の反射器15を配置する。更に、他の2個の反射器15を各IDT電極13、14の内側位置に夫々近接して配置して、回転速度検知ユニット2を構成する。
以上の説明では、圧電基板6の左右の薄肉部6bに、夫々1個のIDT電極とその両側に反射器を配置した場合を説明したが、左右の薄肉部6bに複数のIDT電極を配置してもよい。また、突起部6aと支持基板Pとを接着剤により接着保持すると説明したが、半田バンプ、金バンプ、ガラス材等でもよい。
FIG. 10 is a diagram showing the configuration of a fourth embodiment of the rotation speed detection unit, where FIG. 10 (a) is a plan view and FIG. 10 (b) is a cross-sectional view taken along QQ. Two rotation speed detection units 2 are provided on the other main surface of the piezoelectric substrate 6 and the piezoelectric substrate 6 in which a protrusion 6a and a thin portion 6b having a uniform thickness are formed on both sides of the protrusion 6a. A rotation speed sensitive element S having IDT electrodes 13 and 14 and a plurality of reflectors 15; and a support substrate P that holds the protrusion 6a of the rotation speed sensitive element S by an adhesive (not shown). It is equipped with. An IDT electrode 13 is disposed on one left thin portion 6b of the piezoelectric substrate 6, one reflector 15 is disposed outside the IDT electrode 3, and the other IDT electrode 14 is disposed on the other right thin portion 6b. At the same time, one reflector 15 is arranged outside the IDT electrode 14. Further, the other two reflectors 15 are arranged close to the inner positions of the IDT electrodes 13 and 14 to constitute the rotational speed detection unit 2.
In the above description, the case where one IDT electrode and reflectors are disposed on the left and right thin portions 6b of the piezoelectric substrate 6 has been described. However, a plurality of IDT electrodes are disposed on the left and right thin portions 6b. May be. Moreover, although it demonstrated that the projection part 6a and the support substrate P were adhere | attached and hold | maintained with the adhesive agent, a solder bump, a gold bump, a glass material etc. may be sufficient.

図10に示す圧電基板6の左側に配置したIDT電極13とその両側の各反射器15とでSAW共振子S1を構成し、圧電基板6の右側に配置したIDT電極14とその両側の反射器15とでSAW共振子S2を構成するのは、図9の場合と同様である。図9に示した第3の実施例の回転速度検知ユニットと異なる点は、2個のSAW共振子S1、S2の夫々の内側の反射器15の一部、又は全部が、圧電基板6の突起部6aと対向する主面に形成されている点である。図10に示す回転速度検知ユニット2の動作は、図9の例で説明した通りであり、省略する。
図10に示す第4の実施例の回転速度検知ユニットは、反射器15を突起部6aの対向する主面に形成できるので、圧電基板の寸法を小さくでき、ひいては回転速度検知ユニットの小型化を図れるという利点がある。
The IDT electrode 13 arranged on the left side of the piezoelectric substrate 6 shown in FIG. 10 and the reflectors 15 on both sides thereof constitute a SAW resonator S1, and the IDT electrode 14 arranged on the right side of the piezoelectric substrate 6 and the reflectors on both sides thereof. The SAW resonator S2 is composed of 15 as in the case of FIG. A difference from the rotational speed detection unit of the third embodiment shown in FIG. 9 is that a part or all of the reflectors 15 inside the two SAW resonators S1 and S2 are protruded from the piezoelectric substrate 6. It is a point formed on the main surface facing the portion 6a. The operation of the rotational speed detection unit 2 shown in FIG. 10 is as described in the example of FIG.
In the rotational speed detection unit of the fourth embodiment shown in FIG. 10, the reflector 15 can be formed on the main surface of the projecting portion 6a facing, so that the size of the piezoelectric substrate can be reduced, and the rotational speed detection unit can be downsized. There is an advantage that it can be planned.

図11は、回転速度検知ユニットの第5の実施例の構成を示す図であって、同図(a)は平面図、同図(b)はQ−Qにおける断面図である。第5の実施例の回転速度検知ユニット2が、図10に示した実施例と異なる点は、圧電基板6の両薄肉部6bの一方の主面、又は/及び、他方の主面に重りとして金属膜40を蒸着するか、金属フィラー接着剤又は金属部材40を接着して回転速度検知ユニット2を構成する点である。図11に示す回転速度検知ユニット2の動作は、図9の例で説明した通りであり省略するが、圧電基板6の薄肉部6bに付加した重りのために、回転速度検知ユニット2に回転が加えられると、SAW共振子の周波数変化量が大きくなり、回転速度検知ユニット2の感度が向上する。   FIGS. 11A and 11B are diagrams showing the configuration of the fifth embodiment of the rotational speed detection unit, where FIG. 11A is a plan view and FIG. 11B is a cross-sectional view taken along QQ. The rotational speed detection unit 2 of the fifth embodiment is different from the embodiment shown in FIG. 10 in that one main surface and / or the other main surface of both thin portions 6b of the piezoelectric substrate 6 are weighted. The rotational speed detection unit 2 is configured by depositing the metal film 40 or bonding the metal filler adhesive or the metal member 40. The operation of the rotational speed detection unit 2 shown in FIG. 11 is the same as described in the example of FIG. 9 and is omitted. However, due to the weight added to the thin portion 6b of the piezoelectric substrate 6, the rotational speed detection unit 2 rotates. When added, the amount of change in the frequency of the SAW resonator is increased, and the sensitivity of the rotational speed detection unit 2 is improved.

図12は、回転速度検知ユニットの第6の実施例の構成を示す図であって、同図(a)は平面図、同図(b)はQ−Qにおける断面図である。第6の実施例の回転速度検知ユニット3は、一方の主面に所定の間隔を隔てて2個の凹陥部7bを形成することにより夫々形成した2個の均一な薄肉部を有すると共に略中央部及び両端部に夫々厚肉部7a、7c、7cを有した圧電基板7と、圧電基板7の他方の主面上の略中央部と両端部寄りとに夫々一個ずつ形成した一対の櫛形電極からなるIDT電極10、11、12と、を有した回転速度感応素子Sと、該回転速度感応素子Sの厚肉部7aを接着剤(図示せず)により接着保持する支持基板Pと、を備えている。中央部に配置したIDT電極10を入力部とし、両端部寄りに夫々配置したIDT電極11、12の極性の異なる櫛形電極同士を並列接続し出力部として回転速度検知ユニット3を構成する。
図12に示す回転速度検知ユニット3の動作は、図1の実施例で説明した通りであるので省略する。圧電基板7の両端部に厚肉部7c、7cを設けたので、この質量のために回転速度検知ユニット3に回転が加わると、IDT電極11、12に発生する電荷の量が大きくなり、回転速度検知ユニット2の感度が向上する。
図12に示した略中央部と両端部に夫々厚肉部を有する圧電基板7を、図7、図9、図10、図11の第2〜第5の実施例に適用することができる。
FIG. 12 is a diagram showing the configuration of the sixth embodiment of the rotational speed detection unit, where FIG. 12 (a) is a plan view and FIG. 12 (b) is a cross-sectional view taken along QQ. The rotational speed detection unit 3 of the sixth embodiment has two uniform thin portions formed by forming two concave portions 7b on one main surface at a predetermined interval, and is substantially in the center. And a pair of comb-shaped electrodes formed on the other main surface of the piezoelectric substrate 7 and one near the both ends, respectively, on the piezoelectric substrate 7 having thick portions 7a, 7c, and 7c on both sides. A rotational speed sensitive element S having IDT electrodes 10, 11, and 12, and a support substrate P that adheres and holds the thick portion 7 a of the rotational speed sensitive element S with an adhesive (not shown). I have. The rotational speed detection unit 3 is configured with the IDT electrode 10 arranged in the center as an input part, and comb-shaped electrodes having different polarities of the IDT electrodes 11 and 12 arranged near both ends are connected in parallel.
The operation of the rotational speed detection unit 3 shown in FIG. 12 is the same as described in the embodiment of FIG. Since the thick portions 7c and 7c are provided at both ends of the piezoelectric substrate 7, if rotation is applied to the rotation speed detection unit 3 due to this mass, the amount of charge generated in the IDT electrodes 11 and 12 increases, and rotation occurs. The sensitivity of the speed detection unit 2 is improved.
The piezoelectric substrate 7 having thick portions at the substantially central portion and both end portions shown in FIG. 12 can be applied to the second to fifth embodiments of FIGS. 7, 9, 10, and 11.

図13は、図1に示したような略中央部に突起部6aを有する圧電基板6の製造方法を説明するためのフロー図である。このフロー図は、図13の左上隅に示した圧電基板6の製造方法を示している。図13(a)のように平板の矩形状の水晶基板51を洗浄・乾燥した後、同図(b)のように、図示しない真空装置内に入れ、所定の温度に保ちながら蒸着、あるいはスパッタ等の方法で、水晶基板51の両主面にクロムを蒸着し、続いて金を蒸着し、クロム52と金53の薄膜を形成する。次に、図13(c)に示すようにクロムと金の薄膜52、53の上にレジスト膜54を塗布し、乾燥する。レジスト膜54を、マスクを介して露光、現像し、露光した部分のレジスト膜54剥離すると、図13(d)に示すようにレジスト膜54が所望の形状に加工される。次に金、クロムのエッチング液に夫々浸漬し、露呈した金属膜を溶解すると、図13(e)に示すようにエッチングする部分の金、クロム薄膜が除去される。これを水晶エッチング液中で所定の時間エッチングすると、図13(f)に示すように所望の形状にエッチングされる。レジスト膜54、金薄膜53、クロム膜52を剥離して、図13(g)に示すように略中央部に突起部6aを有する圧電基板6が得られる。水晶基板をエッチングすると結晶の異方性により、軸方向によりエッチング速度が異なり、所望の形状からずれる場合がある。ドライエッチングの場合は時間が掛かる所望の形状に加工できるという利点がある。   FIG. 13 is a flowchart for explaining a method of manufacturing the piezoelectric substrate 6 having the protrusion 6a at the substantially central portion as shown in FIG. This flowchart shows a method of manufacturing the piezoelectric substrate 6 shown in the upper left corner of FIG. After cleaning and drying the flat rectangular quartz substrate 51 as shown in FIG. 13A, it is placed in a vacuum device (not shown) as shown in FIG. In this manner, chromium is vapor-deposited on both main surfaces of the quartz substrate 51, and then gold is vapor-deposited to form a thin film of chromium 52 and gold 53. Next, as shown in FIG. 13C, a resist film 54 is applied on the chromium and gold thin films 52 and 53 and dried. When the resist film 54 is exposed and developed through a mask and the exposed portion of the resist film 54 is peeled off, the resist film 54 is processed into a desired shape as shown in FIG. Next, when the exposed metal film is soaked in an etching solution of gold and chromium, respectively, the gold and chromium thin films to be etched are removed as shown in FIG. When this is etched for a predetermined time in a crystal etching solution, it is etched into a desired shape as shown in FIG. The resist film 54, the gold thin film 53, and the chromium film 52 are peeled off to obtain the piezoelectric substrate 6 having the protrusion 6a at the substantially central portion as shown in FIG. When the quartz substrate is etched, the etching rate varies depending on the axial direction due to the anisotropy of the crystal, which may deviate from a desired shape. In the case of dry etching, there is an advantage that it can be processed into a desired shape which takes time.

図14は、図12に示すような略中央部と両端部に夫々厚肉部を有する圧電基板7の製造方法を説明するフロー図である。図14(a)は、同図左上隅の圧電基板7の裏面図、同図(b)は正面図である。図13で説明したように、圧電基板の両面にクロムと金の薄膜を形成し、その上にレジスト膜を塗布し、マスクを介して露光し、露光した部分のレジスト膜を剥離した状態である。圧電基板のエッチングする部分のレジスト膜と、金とクロムの薄膜とを剥離し、エッチングをしない部分は残す。図14(c)は、圧電基板7をエッチング液に浸漬し、少しエッチングをした状態である。この圧電基板を更にエッチング液中でエッチングすると、図14(d)の状態を経てエッチングが進み、所定の時間浸漬した後、レジスト膜と、金とクロムの薄膜を剥離すると図14(e)に示すような略中央部と両端部が厚肉部を有する圧電基板が得られる。   FIG. 14 is a flowchart for explaining a method of manufacturing the piezoelectric substrate 7 having thick portions at the substantially central portion and both end portions as shown in FIG. FIG. 14A is a rear view of the piezoelectric substrate 7 in the upper left corner of the figure, and FIG. 14B is a front view. As described in FIG. 13, a thin film of chrome and gold is formed on both surfaces of the piezoelectric substrate, a resist film is applied thereon, exposed through a mask, and the exposed resist film is peeled off. . The resist film in the portion to be etched of the piezoelectric substrate is peeled off from the gold and chromium thin film, and the portion that is not etched is left. FIG. 14C shows a state in which the piezoelectric substrate 7 is immersed in an etching solution and slightly etched. When this piezoelectric substrate is further etched in an etching solution, the etching proceeds through the state shown in FIG. 14 (d). After immersion for a predetermined time, the resist film and the gold / chromium thin film are peeled off to obtain FIG. 14 (e). A piezoelectric substrate having a substantially central portion and thick portions at both ends as shown in the drawing is obtained.

図15は、回転速度センサの一例であり、上記の回転速度検知ユニットと、発振回路61と、信号処理回路62、63と、回転速度検知ユニットと発振回路と及び信号処理回路を収容するハウジング60と、を備えた回転速度センサを構成する。図15では、図1に示す回転速度検知ユニット1を用いたが、上記に説明した他の回転速度検知ユニットを用いてもよい。本発明に係る弾性表面波を用いた回転速度検知ユニットは、小型で低背化が図られるため、厚みの薄い回転速度センサが構成できるという効果がある。   FIG. 15 is an example of a rotational speed sensor, and a housing 60 that houses the rotational speed detection unit, the oscillation circuit 61, the signal processing circuits 62 and 63, the rotational speed detection unit, the oscillation circuit, and the signal processing circuit. And a rotational speed sensor comprising: Although the rotational speed detection unit 1 shown in FIG. 1 is used in FIG. 15, the other rotational speed detection units described above may be used. Since the rotational speed detection unit using the surface acoustic wave according to the present invention is small in size and low in height, there is an effect that a rotational speed sensor having a small thickness can be configured.

以上では、回転速度検知ユニット及び回転速度センサについて説明したが、これらは、加速度検知ユニット及び加速度センサとしても使用できる。
また、以上の説明では不平衡型のIDT電極を用いて説明したが、平衡終端のIDT電極をもちいると不要信号の強い回転速度検知ユニット及び回転速度センサが構成できる。
Although the rotation speed detection unit and the rotation speed sensor have been described above, they can also be used as an acceleration detection unit and an acceleration sensor.
In the above description, an unbalanced IDT electrode has been used. However, if a balanced terminal IDT electrode is used, a rotational speed detection unit and a rotational speed sensor with strong unnecessary signals can be configured.

本発明に係る回転速度検知ユニットの構成を示す図であり、(a)は平面図、(b)は断面図である。It is a figure which shows the structure of the rotational speed detection unit which concerns on this invention, (a) is a top view, (b) is sectional drawing. 図1の実施例をセラミックパッケージに収納した平面図である。It is the top view which accommodated the Example of FIG. 1 in the ceramic package. 図1の実施例の動作を説明するためのIDT電極構成を示す図である。It is a figure which shows the IDT electrode structure for demonstrating operation | movement of the Example of FIG. 図1の実施例の回転速度検知ユニットに回転が加えられたときの、(a)は圧電基板の変形を示す正面図、(b)はIDT電極上に発生する電荷を示す図である。FIG. 2A is a front view showing deformation of a piezoelectric substrate and FIG. 2B is a view showing electric charges generated on an IDT electrode when rotation is applied to the rotation speed detection unit of the embodiment of FIG. 回転速度検知ユニットの、(a)は静止状態の出力周波数応答を示す図、(b)は回転が加えられたときの出力周波数応答を示す図である。(A) of a rotational speed detection unit is a figure which shows the output frequency response of a stationary state, (b) is a figure which shows an output frequency response when rotation is added. 回転速度検知ユニットに外力が印加されたときの、(a)は圧電基板の変形状態を示す図、(b)はIDT電極上の電荷発生状態を示す図である。(A) is a figure which shows the deformation | transformation state of a piezoelectric substrate when an external force is applied to a rotational speed detection unit, (b) is a figure which shows the electric charge generation state on an IDT electrode. 図2の実施例のIDT電極構成とある瞬間の電荷発生状態を示す図である。It is a figure which shows the IDT electrode structure of the Example of FIG. 2, and the electric charge generation state of a certain moment. (a)〜(e)は回転速度検知ユニットに発生する電圧の処理方法を説明する図である。(A)-(e) is a figure explaining the processing method of the voltage which generate | occur | produces in a rotational speed detection unit. 回転速度検知ユニットの第3の実施例の構成を示す図であり、(a)は平面図、(b)は断面図である。It is a figure which shows the structure of the 3rd Example of a rotational speed detection unit, (a) is a top view, (b) is sectional drawing. 回転速度検知ユニットの第4の実施例の構成を示す図であり、(a)は平面図、(b)は断面図である。It is a figure which shows the structure of the 4th Example of a rotational speed detection unit, (a) is a top view, (b) is sectional drawing. 回転速度検知ユニットの第5の実施例の構成を示す図であり、(a)は平面図、(b)は断面図である。It is a figure which shows the structure of the 5th Example of a rotational speed detection unit, (a) is a top view, (b) is sectional drawing. 回転速度検知ユニットの第6の実施例の構成を示す図であり、(a)は平面図、(b)は断面図である。It is a figure which shows the structure of the 6th Example of a rotational speed detection unit, (a) is a top view, (b) is sectional drawing. (a)〜(g)は略中央部に突起部を有する圧電基板の製造フローを説明する図である。(A)-(g) is a figure explaining the manufacturing flow of the piezoelectric substrate which has a projection part in the approximate center part. (a)〜(e)は略中央部と両端部に厚肉部を有する圧電基板の製造フローを説明する図である。(A)-(e) is a figure explaining the manufacturing flow of the piezoelectric substrate which has a thick part in a substantially center part and both ends. 回転速度センサの構成を示す概略斜視図である。It is a schematic perspective view which shows the structure of a rotational speed sensor. 従来の外力センサを示す正面図である。It is a front view which shows the conventional external force sensor.

符号の説明Explanation of symbols

1、2、3 回転速度検知ユニット、6、7 圧電基板、6a 突起部、6b 薄肉部、7a、7c 厚肉部、7b 凹陥部、10、11、12、13、14 IDT電極、15 反射器、16 ボンディングパッド、20 音波吸収材、30、31、32、33 端子電極、35 ボンディングワイヤ、40 重り、51 圧電基板、52 クロム薄膜、53 金薄膜、54 レジスト膜、60 ハウジング、61 発振回路、62、63 信号処理回路、P 支持基板、S 回転速度感応素子、L1、L2 IDT電極10の中心と、IDT電極11、12夫々の中心との距離   1, 2, 3 Rotational speed detection unit, 6, 7 Piezoelectric substrate, 6a Protruding part, 6b Thin part, 7a, 7c Thick part, 7b Concave part 10, 11, 12, 13, 14 IDT electrode, 15 reflector , 16 Bonding pad, 20 Sound absorbing material, 30, 31, 32, 33 Terminal electrode, 35 Bonding wire, 40 Weight, 51 Piezoelectric substrate, 52 Chrome thin film, 53 Gold thin film, 54 Resist film, 60 Housing, 61 Oscillator circuit, 62, 63 Signal processing circuit, P support substrate, S rotational speed sensing element, L1, L2 Distance between center of IDT electrode 10 and center of IDT electrodes 11, 12

Claims (8)

一方の主面の略中央部に突起部を有すると共に該突起部の両側に均一な薄肉部を有した圧電基板と、前記圧電基板の他方の主面上の略中央部と両端部寄りに夫々少なくとも一個ずつ形成したIDT電極と、を有した回転速度感応素子と、
前記回転速度感応素子の前記突起部を保持部材により固着保持する支持基板と、
を備えた回転速度検知ユニットであって、
前記略中央部に配置したIDT電極と、前記両端部寄り位置に夫々配置したIDT電極のうちの一方の端部寄り位置に配置したIDT電極との間の位相推移と、
前記略中央部に配置したIDT電極と、前記両端部寄り位置に夫々配置したIDT電極のうちの他方の端部寄り位置に配置したIDT電極との間の位相推移と、が互いに180°異なっていることを特徴とする回転速度検知ユニット。
A piezoelectric substrate having a protrusion at a substantially central portion of one main surface and a uniform thin portion on both sides of the protrusion, and a substantially central portion on the other main surface of the piezoelectric substrate and close to both ends, respectively. A rotational speed sensitive element having at least one IDT electrode formed;
A support substrate that holds and holds the protrusion of the rotational speed sensing element by a holding member;
A rotational speed detection unit comprising:
Phase transition between the IDT electrode arranged at the substantially central portion and the IDT electrode arranged at one end portion of the IDT electrodes arranged at the positions near the both ends,
The phase transition between the IDT electrode arranged at the substantially central portion and the IDT electrode arranged at the other end portion of the IDT electrodes arranged at the positions near the both end portions is different from each other by 180 °. Rotational speed detection unit characterized by that.
一方の主面の略中央部に突起部を有すると共に該突起部の両側に均一な薄肉部を有した圧電基板と、前記圧電基板の他方の主面上に形成された少なくとも2個のIDT電極と複数の反射器と、を有した回転速度感応素子と、
前記回転速度感応素子の前記突起部を保持部材により固着保持する支持基板と、
を備えた回転速度検知ユニットであって、
前記圧電基板の一方の薄肉部には、少なくとも1個のIDT電極と、該IDT電極の両側に反射器とを配置し、
前記圧電基板の他方の薄肉部には、少なくとも1個のIDT電極と、該IDT電極の両側に反射器とを配置したことを特徴とする回転速度検知ユニット。
A piezoelectric substrate having a protrusion at a substantially central portion of one main surface and a uniform thin portion on both sides of the protrusion, and at least two IDT electrodes formed on the other main surface of the piezoelectric substrate And a rotational speed sensing element having a plurality of reflectors,
A support substrate that holds and holds the protrusion of the rotational speed sensing element by a holding member;
A rotational speed detection unit comprising:
At least one IDT electrode and reflectors on both sides of the IDT electrode are arranged on one thin part of the piezoelectric substrate,
At least one IDT electrode and reflectors on both sides of the IDT electrode are arranged on the other thin part of the piezoelectric substrate.
一方の主面の略中央部に突起部を有すると共に該突起部の両側に均一な薄肉部を有した圧電基板と、前記圧電基板の他方の主面上に形成された少なくとも2個のIDT電極及び複数の反射器と、を有した回転速度感応素子と、
前記回転速度感応素子の前記突起部を保持部材により固着保持する支持基板と、
を備えた回転速度検知ユニットであって、
前記圧電基板の一方の薄肉部には、少なくとも1個のIDT電極と、該IDT電極の外側に反射器を配置し、
前記圧電基板の他方の薄肉部には、少なくとも1個のIDT電極と、該IDT電極の外側に反射器を配置し、
前記夫々のIDT電極の内側に夫々反射器を近接配置したことを特徴とする回転速度検知ユニット。
A piezoelectric substrate having a protrusion at a substantially central portion of one main surface and a uniform thin portion on both sides of the protrusion, and at least two IDT electrodes formed on the other main surface of the piezoelectric substrate And a plurality of reflectors, a rotational speed sensitive element having,
A support substrate that holds and holds the protrusion of the rotational speed sensing element by a holding member;
A rotational speed detection unit comprising:
At least one IDT electrode and a reflector outside the IDT electrode are disposed on one thin portion of the piezoelectric substrate,
On the other thin part of the piezoelectric substrate, at least one IDT electrode and a reflector outside the IDT electrode,
A rotational speed detection unit, wherein reflectors are arranged close to each inside of each IDT electrode.
前記圧電基板の両薄肉部の一方の主面、又は/及び、他方の主面に、重りとして金属膜を蒸着するか、金属フィラー接着剤又は金属部材を接着したことを特徴とする請求項1乃至3の何れか一項に記載の回転速度検知ユニット。   2. A metal film is vapor-deposited as a weight, or a metal filler adhesive or a metal member is bonded to one main surface and / or the other main surface of both thin portions of the piezoelectric substrate. The rotational speed detection unit as described in any one of thru | or 3. 一方の主面に所定の間隔を隔てて2個の凹陥部を形成することにより夫々形成した2個の均一な薄肉部を有すると共に略中央部及び両端部に夫々厚肉部を有した圧電基板と、該圧電基板の他方の主面上の略中央部と両端部寄りに夫々少なくとも一個ずつ形成したIDT電極と、を有した回転速度感応素子と、
前記回転速度感応素子の前記略中央部の厚肉部を保持部材により固着保持する支持基板と、
を備えた回転速度検知ユニットであって、
前記略中央部に配置したIDT電極と、前記両端部寄り位置に夫々配置したIDT電極のうちの一方の端部寄り位置に配置したIDT電極との間の位相推移と、
前記略中央部に配置したIDT電極と、前記両端部寄り位置に夫々配置したIDT電極のうちの他方の端部寄り位置に配置したIDT電極との間の位相推移と、が互いに180°異なっていることを特徴とする回転速度検知ユニット。
A piezoelectric substrate having two uniform thin portions each formed by forming two recessed portions at a predetermined interval on one main surface, and having thick portions at substantially the center and both ends. And a rotational speed sensitive element having at least one IDT electrode formed on the other principal surface of the piezoelectric substrate and at least one IDT electrode near both ends,
A support substrate that holds and holds the thick portion of the substantially central portion of the rotational speed sensing element by a holding member;
A rotational speed detection unit comprising:
Phase transition between the IDT electrode arranged at the substantially central portion and the IDT electrode arranged at one end portion of the IDT electrodes arranged at the positions near the both ends,
The phase transition between the IDT electrode arranged at the substantially central portion and the IDT electrode arranged at the other end portion of the IDT electrodes arranged at the positions near the both end portions is different from each other by 180 °. Rotational speed detection unit characterized by that.
一方の主面に所定の間隔を隔てて2個の凹陥部を形成することにより夫々形成した2個の薄肉部を有すると共に中央部及び両端部に夫々厚肉部を有した圧電基板と、該圧電基板の他方の主面上に少なくとも2個のIDT電極と複数の反射器とを有した回転速度感応素子と、
前記回転速度感応素子の前記突起部を保持部材により固着保持する支持基板と、
を備えた回転速度検知ユニットであって、
前記圧電基板の一方の薄肉部には、少なくとも1個のIDT電極と、該IDT電極の両側に反射器を配置し、
前記圧電基板の他方の薄肉部には、少なくとも1個のIDT電極と、該IDT電極の両側に夫々形成した反射器を配置したことを特徴とする回転速度検知ユニット。
A piezoelectric substrate having two thin portions formed by forming two recessed portions at a predetermined interval on one main surface and having thick portions at the center and both ends, A rotational speed sensitive element having at least two IDT electrodes and a plurality of reflectors on the other main surface of the piezoelectric substrate;
A support substrate that holds and holds the protrusion of the rotational speed sensing element by a holding member;
A rotational speed detection unit comprising:
At least one IDT electrode and reflectors on both sides of the IDT electrode are disposed on one thin portion of the piezoelectric substrate,
At least one IDT electrode and reflectors formed on both sides of the IDT electrode are arranged on the other thin part of the piezoelectric substrate, respectively.
一方の主面に所定の間隔を隔てて2個の凹陥部を形成することにより夫々形成した2個の薄肉部を有すると共に中央部及び両端部に夫々厚肉部を有した圧電基板と、該圧電基板の他方の主面上に少なくとも2個のIDT電極と複数の反射器とを有した回転速度感応素子と、
前記回転速度感応素子の前記突起部を保持部材により固着保持する支持基板と、
を備えた回転速度検知ユニットであって、
前記圧電基板の一方の薄肉部には、少なくとも1個のIDT電極と、該IDT電極の外側に反射器を配置し、
前記圧電基板の他方の薄肉部には、少なくとも1個のIDT電極と、該IDT電極の外側に反射器を配置し、
前記夫々のIDT電極の圧電基板中央寄りに近接して反射器を配置したことを特徴とする回転速度検知ユニット。
A piezoelectric substrate having two thin portions formed by forming two recessed portions at a predetermined interval on one main surface and having thick portions at the center and both ends, A rotational speed sensitive element having at least two IDT electrodes and a plurality of reflectors on the other main surface of the piezoelectric substrate;
A support substrate that holds and holds the protrusion of the rotational speed sensing element by a holding member;
A rotational speed detection unit comprising:
At least one IDT electrode and a reflector outside the IDT electrode are disposed on one thin portion of the piezoelectric substrate,
On the other thin part of the piezoelectric substrate, at least one IDT electrode and a reflector outside the IDT electrode,
A rotational speed detection unit, wherein a reflector is arranged close to the center of the piezoelectric substrate of each IDT electrode.
請求項1乃至7のいずれか一項に記載の回転速度検知ユニットと、発振回路と、信号処理回路と、を備えたことを特徴とする回転速度センサ。   A rotational speed sensor comprising the rotational speed detection unit according to claim 1, an oscillation circuit, and a signal processing circuit.
JP2007128848A 2007-05-15 2007-05-15 Rotational speed detecting unit, and rotational speed sensor Withdrawn JP2008286521A (en)

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