JP6517553B2 - Angular velocity sensor - Google Patents

Description

  The present invention relates to an angular velocity sensor.

  A piezoelectric vibration type angular velocity sensor (gyro sensor) is known (for example, Patent Document 1). The angular velocity sensor includes, for example, a sensor element, an IC electrically connected to the sensor element, and a package that accommodates these. The sensor element has a sensor base made of a piezoelectric body, an excitation electrode and a detection electrode provided on the sensor base, and is joined to a pad provided on the inner surface of the package by a bump such as solder. When an alternating voltage is applied to the sensor substrate by the excitation electrode and the sensor substrate is rotated while the sensor substrate is vibrating, a Coriolis force of a magnitude corresponding to the angular velocity is generated. Vibrate. The angular velocity is detected by taking out the electric signal by the vibration by the detection electrode.

JP, 2006-201053, A

  In the angular velocity sensor as described above, the thermal stress generated due to the difference between the thermal expansion coefficients of the package and the sensor element may affect the detection accuracy of the angular velocity. For example, when thermal stress is generated in the sensor element, the vibration characteristic of the sensor element may be changed, and the detection accuracy may be reduced. Also, for example, when thermal stress is applied to the joint between the package and the sensor element, the attitude of the sensor element with respect to the package may be changed, which may reduce detection accuracy. A change in temperature of the angular velocity sensor is caused, for example, by a change in ambient temperature when the angular velocity sensor is used, or is generated by heat for melting the solder when the angular velocity sensor is mounted on a mother board or the like.

  From the above, it is desirable to provide an angular velocity sensor capable of reducing the influence of thermal stress on the detection accuracy of the sensor element.

  An angular velocity sensor according to an aspect of the present invention comprises: a sensor base made of a piezoelectric material; a sensor element having an excitation electrode and a detection electrode provided on the sensor base; and an insulation made of a material different from the material of the sensor base. A mounting base having a base and a plurality of external terminals provided on the insulating base, and the same material as the material of the sensor base, which is bonded to the sensor element and bonded to the mounting base And an intermediate base indirectly holding the sensor element on the mounting base.

  Preferably, the bonding strength between the intermediate substrate and the mounting substrate is higher than the bonding strength between the sensor element and the intermediate substrate.

  Preferably, the sensor base and the intermediate base are made of single crystals, and are bonded in a state in which the crystal orientations are matched with each other.

  Preferably, the sensor base comprises a base, one or more drive arms extending from the base and provided with the excitation electrode, and from the base in the same plane as the detection arm, the detection electrode And the insulating base has a first surface provided with the plurality of external terminals and a second surface on the back surface, and the intermediate base is provided with A third surface opposite to the second surface and bonded to the second surface by a bump, and a back surface of the third surface, and a fourth surface opposed to the sensor element and bonded to the sensor element by a bump And.

  Preferably, the one or more drive arms and the one or more detection arms all extend in a predetermined direction, and the sensor base is on both lateral sides of the one or more drive arms and the one or more detection arms. And two mounting arms extending from the base to one side in the predetermined direction and two mounting arms extending from the base to the other side in the predetermined direction, the tip side of the four mounting arms It is bonded to the intermediate substrate.

  Preferably, the angular velocity sensor includes the mounting substrate as a part thereof, and a package that accommodates the sensor element and the intermediate substrate.

  According to the above configuration, the influence of the thermal stress on the detection accuracy of the sensor element can be reduced.

FIG. 1 is a perspective view showing a sensor element having an angular velocity sensor according to a first embodiment of the present invention. The top view which shows the sensor element of FIG. Fig.3 (a) is sectional drawing in the IIIa-IIIa line of FIG. 1, FIG.3 (b) is sectional drawing in the IIIb-IIIb line of FIG. FIGS. 4 (a) and 4 (b) are schematic cross-sectional views for explaining potentials and the like in the drive arm and the detection arm. FIG. 5 (a) is a schematic view for explaining the excitation of all drive arms in the x-axis direction, and FIG. 5 (b) is a schematic view for explaining the vibrations of all drive arms and all detection arms in the z-axis direction. FIG. 2 is a schematic perspective view more than FIG. 1 for showing an example of wiring of the sensor element of FIG. 1; The disassembled perspective view of the angular velocity sensor which has a sensor element of FIG. Sectional drawing in the VIII-VIII line of FIG. Sectional drawing of the angular velocity sensor which concerns on 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following drawings are schematic. Therefore, details may be omitted, and dimensional ratios and the like do not necessarily coincide with actual ones.

  Each drawing is attached with an orthogonal coordinate system xyz for the convenience of description. The orthogonal coordinate system xyz is defined based on the shape of the sensor element. That is, the x-axis, y-axis and z-axis do not necessarily indicate the electrical, mechanical and optical axes of the crystal. In addition, either direction of the sensor element and the angular velocity sensor may be upward or downward.

  About the same or similar composition, like "the 1st drive arm 11A" and "the 2nd drive arm 11B", a different number and an alphabet may be attached to the same name, and they may be called. In some cases, they are simply referred to as "drive arms 11," and these may not be distinguished.

First Embodiment
(Configuration of sensor element)
FIG. 1 is a perspective view showing a sensor element 1 of an angular velocity sensor 101 according to a first embodiment of the present invention. FIG. 2 is a plan view of the sensor element 1.

  The sensor element 1 is, for example, for detecting an angular velocity around the y axis. The angular velocity sensor 101 is of a piezoelectric vibration type, and the sensor element 1 is configured to be excited in, for example, the x-axis direction and to generate Coriolis force in the z-axis direction. Specifically, for example, it is as follows.

  The sensor element 1 comprises a sensor base 3 made of a piezoelectric material, a first excitation electrode 5A and a second excitation electrode 5B (FIG. 1) for applying a voltage to the sensor base 3, and electric signals generated in the sensor base 3 The first detection electrode 7A (FIG. 1) and the second detection electrode 7B (FIG. 1) for taking out, and the first mounting pad 15A to the fourth mounting pad 15D for mounting the sensor element 1 on a mounting base described later Have.

The sensor base 3 is integrally formed in its entirety. The piezoelectric body constituting the sensor base 3 may be single crystal or polycrystal. Also, the material of the piezoelectric body may be selected appropriately, and is, for example, quartz crystal (SiO ₂ ), LiTaO ₃ , LiNbO ₃ , PZT.

  In the sensor base 3, the electric axis or the polarization axis (hereinafter, both may be representatively referred to only for the polarization axis) is set to coincide with the x axis. The polarization axis may be inclined with respect to the x axis within a predetermined range (for example, within 15 °). When the sensor base 3 is a single crystal, the mechanical axis and the optical axis may be in appropriate directions, but for example, the mechanical axis is in the y-axis direction and the optical axis is in the z-axis direction.

  The sensor base 3 has a base 9 extending in the x-axis direction and various arms (10A to 10D, 11A to 11D, 13A and 13B) extending from the base 9 to the positive side or the negative side of the y-axis direction. . The various arms extend in the same plane (xy plane). In the following, the term "planar view" refers to viewing this plane.

  The first drive arm 11A to the fourth drive arm 11D are portions which are excited in the x-axis direction (hereinafter sometimes referred to as "excitation direction") by application of a voltage (electric field). The first detection arm 13A and the second detection arm 13B are portions that are vibrated in the z-axis direction (hereinafter sometimes referred to as "detection direction") by the Coriolis force and generate an electrical signal according to the angular velocity. The base 9 is a portion that supports the drive arm 11 and the detection arm 13. The first mounting arm 10A to the fourth mounting arm 10D are portions that support the base 9. The positions, shapes, and the like of these are set, for example, as follows.

  The sensor base 3 generally has a constant thickness (z-axis direction) as a whole, and is formed in line symmetry with respect to a center line CL0 (FIG. 2) extending in the y-axis direction.

  The base 9 has a substantially rectangular parallelepiped shape. The dimensional ratio in the three axial directions of the base 9 may be set appropriately. The base 9 is set to have a size in the x-axis direction> a size in the y-axis direction> a size in the z-axis direction. That is, the base 9 has a substantially rectangular plate shape in which the x-axis direction is the longitudinal direction and the z-axis direction is the thickness direction. The size in the x-axis direction may be larger than the size in the z-axis direction ≧ the size in the y-axis direction.

  The four mounting arms 10 extend from both ends 9a of the base 9 (outside portions of all other arms in the x-axis direction) to both sides in the y-axis direction (although they may not be parallel to the y-axis) ). The mounting arm 10 does not have to be parallel to the drive arm 11 and the detection arm 13, but is parallel in the present embodiment. The four mounting arms 10 are provided so as to be arranged and shaped in line symmetry in any of the x-axis direction and the y-axis direction. Although the specific shape of the mounting arm 10 may be set as appropriate, it is, for example, a substantially rectangular plate. Various dimensions, such as the length of the mounting arm 10, may be set appropriately. In the present embodiment, the mounting arm 10 is equal to or less than the length of the drive arm 11 and the detection arm 13.

  The plurality of drive arms 11 extend in parallel (parallel) with each other in the same direction (positive side in the y-axis direction), and their tips are free ends. The number of drive arms 11 is an even number (4 in the present embodiment). The even numbered drive arms 11 are arranged in line symmetry with each other with respect to the center line CL0. Further, the shape of the even numbered drive arms 11 is also symmetrical with respect to the center line CL0. That is, the first drive arm 11A and the fourth drive arm 11D are arranged and shaped in line symmetry with each other with respect to the center line CL0, and the second drive arm 11B and the third drive arm 11C are arranged at the center line CL0. The arrangement and shape are symmetrical with respect to each other. The driving arms 11 (for example, 11A and 11B) adjacent to each other are identical to each other and / or line symmetrical with respect to a symmetry axis (CL1 or CL2 shown in FIG. 2).

  As will be described later, since the plurality of drive arms 11 (11A and 11B) on one side of the center line CL0 vibrate so as to curve together to the same side, one virtual drive arm is configured as a whole. Similarly, the plurality of drive arms 11 (11C and 11D) on the other side of the center line CL0 form one virtual drive arm as a whole. As a result of the axisymmetric shape and arrangement as described above, the two virtual drive arms are axisymmetric with respect to their vibration-related characteristics. In other words, if the positive and negative directions in the lateral direction are defined symmetrically with respect to the center line CL0, the characteristics relating to the both vibrations are the same, and the natural frequencies and the like are also the same.

  The shape of the drive arm 11 is a rectangular parallelepiped whose longitudinal direction is in the y-axis direction, and grooves 11a (see also FIG. 3A) extending in the y-axis direction are formed on the positive and negative sides in the z-axis direction. It has a different shape. The cross-sectional shape of the recessed groove 11a is, for example, a substantially rectangular shape. The concave groove 11a may be omitted. In addition, the drive arm 11 may be formed so as to have a wide tip end, so as to have a so-called hammer shape.

  When the width (x-axis direction) of the drive arm 11 increases, the natural frequency in the excitation direction (x-axis direction) of the drive arm 11 increases, and when the length (mass) of the drive arm 11 increases, The natural frequency in the excitation direction is low. Therefore, various dimensions of the drive arm 11 are set according to the frequency to be excited. Preferably, the natural frequency of the drive arm 11 in the x-axis direction is equal to the natural frequency of the z-axis direction.

  The plurality of detection arms 13 extend in parallel (parallel) with each other in the direction (the negative side in the y-axis direction) opposite to the direction in which the plurality of drive arms 11 extend, and their tips are free ends. The number of detection arms 13 is an even number (two in the present embodiment) and is smaller than the number of drive arms 11. The even number of detection arms 13 are arranged in line symmetry with each other with respect to the center line CL0. Further, the shapes of the even detection arms 13 are also in line symmetry with each other with respect to the center line CL0.

  Accordingly, as with the drive arm 11, the vibration characteristics of the detection arm 13 are symmetrical to each other on one side and the other side of the center line CL0. In other words, if the positive and negative directions in the lateral direction are defined symmetrically with respect to the center line CL0, the characteristics relating to the both vibrations are the same, and the natural frequencies and the like are also the same.

  The schematic shape of the detection arm 13 is a rectangular parallelepiped. In this rectangular parallelepiped, for example, the size in the y-axis direction> the size in the x-axis direction> the size in the z-axis direction. That is, the detection arm 13 has a substantially rectangular plate shape with the y-axis direction as the longitudinal direction and the z-axis direction as the thickness direction. Therefore, the detection arm 13 is relatively less likely to vibrate in the excitation direction (x-axis direction), and more likely to vibrate in the detection direction (z-axis direction).

  Further, the detection arm 13 penetrates the detection arm 13 in the z-axis direction, and one or more (a plurality of (in the embodiment, plural)) through grooves 13a (see also FIG. 3B) extending in the y-axis direction are formed. It has a different shape. In another aspect, the detection arm 13 extends from the base 9 in the y-axis direction and is aligned in the x-axis direction, and has a plurality of divided arms 13 b whose tips are fixed to one another. The shape of the xz cross section of the split arm 13b (penetration groove 13a) is, for example, a substantially rectangular shape. The through groove 13a may be omitted. In addition, the detection arm 13 may be formed so as to have a wide tip and be in the shape of a so-called hammer.

  Similar to the drive arm 11, various dimensions of the detection arm 13 are set so that the natural frequency in the z-axis direction, which is the direction of the vibration due to the Coriolis force, becomes appropriate because the natural frequency is defined. Be done. Preferably, the natural frequency of the detection arm 13 in the z-axis direction is made equal to the natural frequency of the drive arm 11 in the x-axis direction (the detuning frequency is reduced).

  The relative relationship between the position of the drive arm 11 in the x-axis direction and the position of the detection arm 13 in the x-axis direction is such that the first detection arm 13A is vibrated by the vibration of the first drive arm 11A and the second drive arm 11B. The vibration of the driving arm 11C and the fourth driving arm 11D is appropriately set to vibrate the second detection arm 13B.

  For example, a line CL1 (FIG. 2) parallel to these arms passing through an intermediate position between the first drive arm 11A and the second drive arm 11B coincides with the center line CL13A (FIG. 2) of the first detection arm 13A. ing. Similarly, a line CL2 (FIG. 2) parallel to these arms passing an intermediate position between the third drive arm 11C and the fourth drive arm 11D and a center line CL13B (FIG. 2) of the second detection arm 13B are one. I do. However, these may be shifted.

  The center line of each arm is, for example, a line connecting the center of gravity of the xz cross section of the main body in the y-axis direction. Further, it is also possible to define a center line as a whole of a plurality of arms on one side or the other side (virtual arms) bordering on the center line CL0. For example, a line connecting the centers of gravity of all the first drive arm 11A and the second drive arm 11B in the y-axis direction is the center line CL1 of the entire drive arm 11 on one side of the center line CL0 (virtual drive arm) It can be defined as

  As described above, when the center lines of the plurality of arms as a whole are defined, in the present embodiment, the center line (CL1 of the plurality of driving arms 11 as a whole on each of the one side and the other side having the center line CL0 as a boundary) Alternatively, it can be considered that CL2) and the center line (13A or 13B) of one or more detection arms 13 coincide with each other. This concept is also applicable when the number of drive arms and detection arms is different from that of the present embodiment. For example, when the number of drive arms 11 corresponding to one detection arm 13 is three, the center line of all the three drive arms may be considered, and this center line may be made to coincide with the center line of detection arm 13 . Also, for example, when the three drive arms 11 and the two detection arms 13 correspond to each other, the center line of all the three drive arms 11 matches the center line of all the two detection arms. You may

  The distance D1 between the two drive arms 11 (for example, the distance between the centers: the distance between the center lines of the drive arms 11) is appropriately set on each of the one side and the other side in the x-axis direction with respect to the center line CL0. Ru.

  In the present embodiment, the first drive arm 11A and the second drive arm 11B have an overall outer surface in the x-axis direction (a negative surface of the first drive arm 11A in the x-axis direction and the second drive arm 11B). The surface on the positive side in the x-axis direction is arranged to coincide with the outer surface in the x-axis direction of the first detection arm 13A. The same applies to the third drive arm 11C and the fourth drive arm 11D. Thus, the vibration can be easily transmitted to the entire width direction (x-axis direction) of the detection arm 13. Further, the arrangement range of the drive arm 11 falls within the arrangement range of the detection arm 13, and the sensor base 3 is miniaturized.

  However, the distance between the drive arms 11 may be shorter or longer than in the present embodiment. For example, the center-to-center distance D1 may be shorter than the center-to-center distance between the drive arms 11 (11B and 11C) adjacent to each other across the center line CL0. In this case, the mutual influence between the drive arms 11 adjacent to each other on one side or the other side in the x-axis direction with respect to the center line CL0 becomes larger than the mutual influence between the drive arms 11 adjacent to each other across the center line CL0. .

  Further, on each of the one side and the other side in the x-axis direction with respect to the center line CL0, the center-to-center distance D1 of the plurality (two in the present embodiment) drive arms 11 is based on the center-to-center distance D2 between the detection arms 13 Is also shortened. Thereby, the mutual influence between the two drive arms 11 on one side and the other side of the center line CL0 is larger than the mutual influence between the two detection arms 13 adjacent to each other across the center line CL0. . However, the center-to-center distance D1 between the drive arms 11 on one side and the other side in the x-axis direction with respect to the center line CL0 may be longer than the center-to-center distance D2 between the detection arms 13.

  The four mounting pads 15 are layered conductors provided on the surface on the positive side or the negative side (the positive side in this embodiment) of the tips of the four mounting arms 10 in the z-axis direction. The material is, for example, a suitable metal such as Cu or Al. In addition, the material of the other conductor mentioned later may be similarly made into an appropriate metal. The planar shape of the mounting pad 15 may be set as appropriate, and is, for example, rectangular. By bonding the mounting pad 15 to a mounting base described later by bumps, the sensor element 1 is electrically connected to the mounting base, and the drive arm 11 and the detection arm 13 are supported in a vibratable state. Ru.

  FIG. 3A is a cross-sectional view taken along line IIIa-IIIa of FIG. Although the cross section of 4th drive arm 11D is shown in FIG. 3 (a), the cross section of the other drive arm 11 is also the same.

  The excitation electrode 5 is a layered conductor formed on the surface of the drive arm 11. The first excitation electrodes 5A are provided on the surface on the positive side in the z-axis direction and the surface on the negative side in the z-axis direction in each drive arm 11. As described above, the grooves 11a are formed on these surfaces, and the first excitation electrode 5A covers the bottom surface and the two inner wall surfaces of the grooves 11a on each surface. The second excitation electrodes 5B are provided on the surface on the positive side in the x-axis direction and the surface on the negative side in the x-axis direction in each drive arm 11.

  The two first excitation electrodes 5A and the two second excitation electrodes 5B are provided, for example, to substantially cover each surface of the drive arm 11. However, at least one of the first excitation electrode 5A and the second excitation electrode 5B (in the present embodiment, the first excitation electrode 5A) is formed smaller in the width direction than each surface so as not to short-circuit each other.

  In each drive arm 11, for example, the two first excitation electrodes 5A are at the same potential. For example, the two first excitation electrodes 5A are connected to each other by a wire or the like on the sensor base 3. Further, in each drive arm 11, for example, the two second excitation electrodes 5B are at the same potential. For example, the two second excitation electrodes 5B are connected to each other by a wire or the like on the sensor base 3.

  The additional symbols A and B of the excitation electrode 5 are attached based on the orthogonal coordinate system xyz. Therefore, for example, as described later, the first excitation electrode 5A of one drive arm 11 and the first excitation electrode 5A of the other drive arm 11 are not necessarily at the same potential.

  FIG.3 (b) is sectional drawing in the IIIb-IIIb line | wire of FIG. Although FIG. 3B shows a cross section of a part of the divided arms 13b of the second detection arm 13B, the other divided arms 13b of the second detection arm 13B and the divided arms of the first detection arm 13A. The same applies to the cross section of 13b.

  The detection electrode 7 is a layered conductor formed on the surface of the detection arm 13 (split arm 13 b). The detection electrode 7 is provided on each divided arm 13 b. That is, the detection electrode 7 is provided not only on the outer side surface of the detection arm 13 in the x-axis direction but also on the inner wall surface of the plurality of through grooves 13 a.

  More specifically, in each of the divided arms 13b, the first detection electrode 7A has a region on the positive side in the z-axis direction of the negative side in the x-axis direction and a surface on the positive side in the x-axis direction. It is respectively provided in the area | region of the negative side of z axial direction. The second detection electrode 7B is a region on the negative side in the z-axis direction of the negative sides in the x-axis direction and the z-axis direction on the positive side of the x-axis direction in each of the divided arms 13b. It is provided in the area on the positive side. The first detection electrode 7A and the second detection electrode 7B extend along the split arm 13b at an appropriate interval so as not to short circuit each other.

  In each detection arm 13, the charges extracted from the sensor base 3 by the plurality of first detection electrodes 7A are added. For example, the plurality of first detection electrodes 7A are connected by wiring or the like on the sensor base 3. Further, in each detection arm 13, the charges extracted from the sensor base 3 by the plurality of second detection electrodes 7 </ b> B are added. For example, the plurality of second detection electrodes 7B are connected by wiring or the like on the sensor base 3.

  As in the case of the excitation electrode 5, the additional symbols A and B of the detection electrode 7 are attached based on the orthogonal coordinate system xyz. Therefore, for example, as described later, the first detection electrode 7A of the first detection arm 13A and the first detection electrode 7A of the second detection arm 13B are not connected (in the present embodiment).

  As shown in FIGS. 3A and 3B, the angular velocity sensor 101 has an excitation circuit 103 for applying a voltage to the excitation electrode 5 and a detection circuit 105 for detecting an electrical signal from the detection electrode 7. doing.

  The excitation circuit 103 includes, for example, an oscillation circuit and an amplifier, and applies an AC voltage of a predetermined frequency between the first excitation electrode 5A and the second excitation electrode 5B. The frequency may be predetermined in the angular velocity sensor 101 or may be designated from an external device or the like.

  The detection circuit 105 includes, for example, an amplifier and a detection circuit, detects a potential difference between the first detection electrode 7A and the second detection electrode 7B, and outputs an electric signal corresponding to the detection result to an external device or the like. Output to More specifically, for example, the above-mentioned potential difference is detected as an AC voltage, and the detection circuit 105 outputs a signal according to the amplitude of the detected AC voltage. An angular velocity about the y-axis is identified based on this amplitude. Further, the detection circuit 105 outputs a signal according to the phase difference between the applied voltage of the excitation circuit 103 and the detected electric signal. Based on this phase difference, the direction of rotation about the y-axis is identified.

(Description of operation of sensor element)
FIG. 4A is a view for explaining the potential and the like in the drive arm 11, and is a schematic view corresponding to FIG. 3A. FIG. 4B is a view for explaining the potential and the like in the detection arm 13 and is a schematic view corresponding to FIG. 3B.

  When a positive potential is applied to the first excitation electrode 5A and a negative potential (or reference potential) is applied to the second excitation electrode 5B, an electric field as shown by an arrow in the figure is generated. On the other hand, the polarization axis coincides with the x-axis direction. Therefore, focusing on the component of the electric field in the x-axis direction, the direction of the electric field coincides with the direction of the polarization axis on one side of the drive arm 11 in the x-axis direction, and the direction of the electric field and the polarization axis on the other side The direction of is reversed.

  As a result, one part of the drive arm 11 in the x-axis direction contracts in the y-axis direction, and the other part extends in the y-axis direction. And the drive arm 11 curves to one side of the x-axis direction like a bimetal. When the voltages applied to the first excitation electrode 5A and the second excitation electrode 5B are reversed, the drive arm 11 bends in the opposite direction. According to such a principle, when an AC voltage is applied to the first excitation electrode 5A and the second excitation electrode 5B, the drive arm 11 vibrates in the x-axis direction.

  Here, as described above, the concave groove 11a is formed on the positive side and the negative side of the drive arm 11 on which the first excitation electrode 5A is provided in the z-axis direction. Accordingly, the first excitation electrode 5A has a portion facing the second excitation electrode 5B in the x-axis direction (a portion positioned on the inner wall of the recessed groove 11a), and the area is increased as a whole. As a result, the strength of the electric field in the x-axis direction in the drive arm 11 can be increased, and the drive arm 11 can be efficiently vibrated.

  When the sensor element 1 is rotated about the y-axis, a Coriolis force having a magnitude corresponding to the angular velocity, which is one of the inertial forces, is applied to the drive arm 11 vibrating in the x-axis direction. As a result, the drive arm 11 vibrates in the z-axis direction. Since the drive arm 11 and the detection arm 13 are connected by the base 9 and exert an interaction of forces with each other, the detection arm 13 vibrates in the opposite phase to the drive arm 11 in the z-axis direction (the bending direction of the drive arm 11 Curve in the opposite direction).

  When the detection arm 13 is bent in the z-axis direction, an electric field parallel to the z-axis direction is generated as indicated by an arrow in FIG. 4B. The direction of the electric field is opposite to each other in the positive side and the negative side in the x-axis (polarization axis) direction. Also, the direction of the electric field is determined by the direction of the polarization axis and the direction of the curvature (positive or negative side in the z-axis direction). This voltage (electric field) is output to the first detection electrode 7A and the second detection electrode 7B. When the detection arm 13 vibrates in the z-axis direction, the voltage is detected as an alternating voltage.

  Here, as described above, the detection arm 13 is formed with the plurality of through grooves 13a, and the detection electrode 7 is not only the surface on the positive side and the negative side of the detection arm 13 in the x-axis direction It is also provided on the inner wall surface of the groove 13a. Therefore, the area as a whole is large compared with the case where the detection electrode 7 is provided only in the outer surface of the detection arm 13 in the x-axis direction. As a result, the charge generated in the detection arm 13 can be efficiently extracted as an electrical signal.

  FIG. 5A is a schematic plan view for explaining excitation of the four drive arms 11 in the x-axis direction.

  The first drive arm 11A and the second drive arm 11B are excited in the same phase so as to be deformed to the same side in the excitation direction (x-axis direction). For example, the first excitation electrode 5A of the first drive arm 11A and the first excitation electrode 5A of the second drive arm 11B are connected, and the second excitation electrode 5B of the first drive arm 11A and the second of the second drive arm 11B The excitation electrode 5B is connected, and an AC voltage is applied between the first excitation electrode 5A and the second excitation electrode 5B.

  Similarly, the third drive arm 11C and the fourth drive arm 11D are excited in the same phase so as to deform together to the same side in the excitation direction. Similarly to the above, this excitation may be realized by connecting the first excitation electrodes 5A to each other and connecting the second excitation electrodes 5B to each other between the two drive arms 11.

  The group of the first drive arm 11A and the second drive arm 11B and the group of the third drive arm 11C and the fourth drive arm 11D are in opposite phase (180 ° out of phase with each other so as to be deformed in opposite directions in the excitation direction Phase) is excited. For example, the first excitation electrode 5A of the first drive arm 11A and the second drive arm 11B and the second excitation electrode 5B of the third drive arm 11C and the fourth drive arm 11D are connected (first electrode group), The second excitation electrode 5B of the first drive arm 11A and the second drive arm 11B and the first excitation electrode 5A of the third drive arm 11C and the fourth drive arm 11D are connected (second electrode group), An alternating voltage is applied between the second group of electrodes and the second group of electrodes.

  Since the group of the first drive arm 11A and the second drive arm 11B and the group of the third drive arm 11C and the fourth drive arm 11D vibrate in opposite phases in the x-axis direction, the sensor base 3 Overall, the x-axis forces of these groups cancel each other.

  FIG. 5B is a schematic perspective view for explaining the vibration of the four drive arms 11 and the two detection arms 13 in the z-axis direction. More specifically, as shown in FIG. 5 (a), in FIG. 5 (b), the sensor base 3 in which the driving arm 11 is curved is shown by the arrow y5 around the center line CL0 (around the y axis). It is a perspective view which shows the curved state of the drive arm 11 and the detection arm 13 when rotating to a direction.

  The first drive arm 11A and the second drive arm 11B are disposed on the same side in the radial direction (x-axis direction) with respect to the rotation center (center line CL0). Further, as shown in FIG. 5A, both drive arms 11 are excited so as to curve outward or inward in the radial direction (excitation direction, x-axis direction). Accordingly, the directions of Coriolis force in both drive arms 11 are the same. As a result, as shown in FIG. 5 (b), both drive arms 11 vibrate so as to curve together to the same side in the z-axis direction. Similarly, the third drive arm 11C and the fourth drive arm 11D vibrate so as to bend together to the same side in the z-axis direction by the Coriolis force.

  The group of the first drive arm 11A and the second drive arm 11B and the group of the third drive arm 11C and the fourth drive arm 11D are in the radial direction (x-axis direction) with respect to the rotation center (center line CL0) Are disposed opposite to each other, and the directions of movement by the rotation in the z-axis direction are opposite to each other. Also, as shown in FIG. 5A, when one group is curved outward (or inward) in the radial direction, both groups are also curved outward (or inward) in the radial direction. Is excited. Therefore, the direction of Coriolis force is opposite to each other in both groups. As a result, as shown in FIG. 5B, both groups vibrate so as to curve in opposite directions in the z-axis direction.

  The drive arm 11 and the detection arm 13 are connected by a base 9. Accordingly, the vibration of the drive arm 11 is transmitted to the detection arm 13 through the base 9 and the detection arm 13 also vibrates. Specifically, the first detection arm 13A vibrates so as to curve in the opposite direction to the first drive arm 11A and the second drive arm 11B in the z-axis direction. Further, the second detection arm 13B vibrates so as to curve in the opposite direction to the third drive arm 11C and the fourth drive arm 11D in the z-axis direction.

  The first detection arm 13A and the second detection arm 13B vibrate so as to curve in opposite directions in the z-axis direction. Therefore, in both cases, voltages generated in one side portion (or the other side portion) in the x-axis direction are opposite to each other in the z-axis direction. Therefore, for example, the first detection electrode 7A of the first detection arm 13A and the second detection electrode 7B of the second detection arm 13B are connected, and the second detection electrode 7B of the first detection arm 13A and the second detection arm 13B are connected. By connecting the first detection electrode 7A, the electric signals generated in both detection arms 13 are added.

(Example of wiring)
In the above description of operation, the connection relation of the plurality of excitation electrodes 5 and the plurality of detection electrodes 7 has been mentioned. An example of wiring for realizing this connection relationship is shown in FIG.

  FIG. 6 is a perspective view of the sensor element 1. However, this figure schematically shows the sensor element 1 more schematically than FIG. 1 so that the wiring can be easily recognized. For example, the mounting arm 10 is omitted and the mounting pad 15 is shown at the end 9 a of the base 9. Also, for example, the shapes of the drive arm 11 and the detection arm 13 are simplified and shown, and various electrodes are shown small.

  In this example, the first mounting pad 15A and the second mounting pad 15B are pads to which voltages applied to the plurality of excitation electrodes 5 are input. The third mounting pad 15C and the fourth mounting pad 15D are pads for outputting signals from the plurality of detection electrodes 7.

  The first wiring 17A extends from the first mounting pad 15A. The first wiring 17A is connected to the first excitation electrode 5A of the first drive arm 11A and the second drive arm 11B, and to the second excitation electrode 5B of the third drive arm 11C and the fourth drive arm 11D. Further, the second wiring 17B extends from the second mounting pad 15B. The second wiring 17B is connected to the second excitation electrode 5B of the first drive arm 11A and the second drive arm 11B, and to the first excitation electrode 5A of the third drive arm 11C and the fourth drive arm 11D.

  A third wiring 17C extends from the third mounting pad 15C. The third wiring 17C is connected to the first detection electrode 7A of the first detection arm 13A and the second detection electrode 7B of the second detection arm 13B. In addition, the fourth wiring 17D extends from the fourth mounting pad 15D. The fourth wiring 17D is connected to the second detection electrode 7B of the first detection arm 13A and the first detection electrode 7A of the second detection arm 13B.

  The wirings 17 are appropriately disposed on the four surfaces of the base 9 and the four surfaces of the root side portion and the tip side portion of various arm portions so as not to cross each other, and are appropriately branched or merged.

  The wiring shown in FIG. 6 is merely an example, and the connection relationship of the electrodes mentioned in the description of the operation may be realized by other various patterns. The combination of the four mounting arms 10 and the four types of mounting pads 15 provided thereon may also be changed. The wires 17 may be provided so as to cross each other three-dimensionally via an insulator.

  The method of manufacturing the sensor element 1 described above may be the same as the known method except for the portion related to the specific shape of the sensor base 3. For example, although not shown, the sensor substrate 3 is formed by etching, and a conductive material is formed on the sensor substrate 3 through a deposition mask to form the excitation electrode 5, the detection electrode 7, the mounting pad 15, and the wiring. By forming 17, the sensor element 1 is produced. The etching and the deposition of the conductive material are performed, for example, on a wafer on which a large number of sensor substrates 3 are taken.

  FIG. 7 is an exploded perspective view showing the angular velocity sensor 101 having the sensor element 1. 8 is a cross-sectional view taken along line VIII-VIII of FIG.

  The angular velocity sensor 101 includes, for example, a mounting base 111 having a recess 119a for housing the sensor element 1 and the like in this order from the lower side of the drawing (the positive side in the z-axis direction), the excitation circuit 103 (reference numeral is FIG. 3) The IC 107 includes the IC 107 (shown in FIG. 3), the intermediate member 113 mounted on the mounting base 111, the sensor element 1 mounted on the intermediate member 113, and the lid 115 for closing the recess 119a of the mounting base 111. ing.

  The mounting base 111 and the lid 115 constitute a package 117 (see FIG. 8) for protecting the sensor element 1, the IC 107 and the intermediate member 113. The sensor element 1 is mounted on the intermediate member 113, and the intermediate member 113 is mounted on the mounting base 111 so that the sensor element 1 is indirectly mounted on the mounting base 111. The specific configuration of each member is, for example, as follows.

  The mounting substrate 111 has, for example, an insulating substrate 119 which constitutes the major part thereof, and various conductors provided on the insulating substrate 119. For example, various conductors may be connected to a plurality of IC pads 121 electrically connected to the IC 107, a plurality of intermediate member pads 123 for mounting the intermediate member 113 on the mounting substrate 111, and a circuit (not shown) A plurality of external terminals 125 (FIG. 8) for mounting on a substrate or the like, wires (not shown) connecting a part of the plurality of IC pads 121 and the intermediate member pads 123, and a plurality of IC pads 121 It is a wire (not shown) which connects another part and the external terminal 125.

  The insulating substrate 119 is made of a material different from that of the sensor substrate 3. The different materials mentioned here are particularly from the viewpoint of the thermal expansion coefficient, and for example, those having different compositions and / or structures (for example, molecular structure), and those having single crystals and polycrystals different from each other Do. The material of the insulating substrate 119 is, for example, a ceramic or a resin. Since the insulating base 119 and the sensor base 3 are made of different materials, their thermal expansion coefficients are also different. For example, when the material of the sensor substrate 3 is quartz and the material of the insulating substrate 119 is ceramic (sintered) or resin, generally, the thermal expansion coefficient of the insulating substrate 119 is the thermal expansion coefficient of the sensor substrate 3 Greater than.

  The shape of the insulating base 119 is, for example, a shape in which the recess 119a is formed on the surface of the substantially thin rectangular parallelepiped having the largest area. In the recess 119a, there are provided a base 119b formed higher than the bottom surface of the recess 119a and a pedestal 119c formed higher than the base 119b. The pedestal portions 119 b are provided, for example, on both sides in the direction along the bottom surface of the concave portion 119 a (two in total). The pedestal portions 119 c are provided, for example, at four corners of the bottom surface of the recess 119 a having a rectangular shape in a plan view. The pedestal portion 119 b and / or the pedestal portion 119 c may be formed in a frame shape on the outer periphery of the bottom surface of the concave portion 119 a.

  The IC pad 121 is, for example, a layered conductor provided on the upper surface of the pedestal 119 b. The plurality of IC pads 121 are arranged, for example, along the edge of the pedestal 119 b on the center side of the recess 119 a.

  The intermediate member pad 123 is, for example, a layered conductor provided on the pedestal portion 119c. For example, one intermediate member pad 123 is provided on each of the pedestal portions 119c, and a total of four intermediate member pads 123 are provided.

  The external terminal 125 is, for example, a layered conductor provided on the surface on the positive side in the z-axis direction of the insulating base 119 (the surface on the side opposite to the side where the recess 119a is opened). The external terminals 125 are provided, for example, at four corners or the like of the surface of the insulating base 119 on the z axis direction positive side. The plurality of external terminals 125 are, for example, disposed to face the pads of the circuit board (not shown), and joined to the pads of the circuit board by bumps (not shown). Thus, the angular velocity sensor 101 is mounted on the circuit board.

  The IC 107 may be packaged or may be a bare chip. The outer shape of the IC 107 may be an appropriate shape, but is, for example, a thin rectangular parallelepiped. For example, the IC 107 is fixed to the bottom surface of the recess 119 a with an adhesive or the like, and the IC terminal 107 a formed on the negative side of the IC 107 in the z-axis direction is connected to the IC pad 121 by the bonding wire 127. The mounting base 111 is mounted.

  The intermediate member 113 has, for example, an insulating intermediate base 129 and various conductors provided on the intermediate base 129. For example, various conductors include an intermediate terminal 131 (FIG. 8) for mounting the intermediate member 113 on the mounting base 111, a sensor element pad 133 for mounting the sensor element 1 on the intermediate member 113, and an intermediate terminal 131. Relay wiring 135 (FIG. 7) connecting the sensor element pad 133 to the sensor element pad 133.

  The intermediate base 129 is made of the same material (piezoelectric material) as the material of the sensor base 3. The same as the material referred to here is from the viewpoint of the thermal expansion coefficient, and for example, it means that both the composition and the structure (for example, molecular structure) are the same, and when the material has a crystal structure, It means that both are single crystals or both are polycrystalline. However, for example, there may be differences with regard to some impurities that are unintentionally mixed in the manufacturing process. The shape of the intermediate base 129 is, for example, a rectangular plate having a constant thickness. The dimensions may be set appropriately. However, the sensor element 1 can be mounted in a wide area (a wide area in which the plurality of mounting pads 15 are disposed).

  The intermediate terminal 131 is, for example, a layered conductor provided on the main surface of the intermediate base 129 on the z axis direction positive side. The intermediate terminals 131 are provided, for example, at four corners of the main surface of the intermediate base 129, for a total of four. The intermediate terminal 131 faces the intermediate member pad 123, and is joined to the intermediate member pad 123 by bumps 137 (FIG. 8) made of solder or conductive adhesive. Thus, the intermediate member 113 is electrically connected to and fixed (supported) to the mounting substrate 111.

  The sensor element pad 133 is, for example, a layered conductor provided on the main surface on the negative side in the z-axis direction of the intermediate base 129 (the back surface of the main surface on which the intermediate terminal 131 is provided). The sensor element pads 133 are provided, for example, at four corners of the main surface of the intermediate base 129, and a total of four pads are provided. The mounting pad 15 of the sensor element 1 faces the sensor element pad 133, and is bonded to the sensor element pad 133 by a bump 139 (FIG. 8) made of solder or a conductive adhesive. Thus, the sensor element 1 is electrically connected to the intermediate member 113 and fixed (supported).

  The relay wiring 135 is, for example, a layered conductor formed on the surface of the intermediate base 129, and extends from one main surface of the intermediate base 129 to the other main surface via the outer peripheral surface, thereby the intermediate terminal 131 and the sensor It is connected to the element pad 133. The relay wiring 135 may be configured by a via conductor penetrating the intermediate base 129.

  As described above, the sensor element 1 (mounting pad 15) is fixed to the intermediate member 113 (sensor element pad 133), and the intermediate member 113 (intermediate terminal 131) is fixed to the mounting base 111 (intermediate member pad 123). It is fixed. Thereby, the sensor element 1 is indirectly fixed to the mounting substrate 111 via the intermediate member 113.

  The sensor element 1 (mounting pad 15) is electrically connected to the intermediate member 113 (sensor element pad 133), and the intermediate member 113 (sensor element pad 133 and the relay wire 135 electrically connected to each other). The terminal 131) is electrically connected to the mounting substrate 111 (intermediate member pad 123). As a result, the sensor element 1 is electrically connected to the mounting base 111, and in turn, the IC 107 electrically connected to the mounting base 111 (IC pad 121), and a plurality of mounting bases 111 (intermediate member pads 123). Is connected to the IC 107 via a wire (not shown) connecting a part of the IC pad 121. The IC 107 is electrically connected to the external terminal 125 through the mounting substrate 111 (a wire (not shown) connecting another part of the plurality of IC pads 121 and the external terminal 125).

  When the sensor base 3 and the intermediate base 129 are made of a single crystal, it is preferable that the two be fixed to each other with their crystal orientations aligned. That is, it is preferable that the electrical axis, the mechanical axis, and the optical axis coincide with each other. For example, when the sensor base 3 (strictly, the wafer from which the sensor base 3 is derived) is cut out of a single crystal material at a predetermined cut angle, and the intermediate base 129 is plate-like, the intermediate base 129 (the wafer from which the sensor base 3 is made) is formed, for example, by being cut at the same cut angle from a single crystal material of the same type as the single crystal material from which the sensor substrate 3 was cut. And since these are laminatedly fixed to each other, the orientations of the two crystals coincide with each other.

  It is preferable that the bonding between the mounting base 111 and the intermediate member 113 be higher in strength than the bonding between the sensor element 1 and the intermediate member 113. For example, the intermediate member pad 123 and the intermediate terminal 131 have a larger area (bonding area) than the sensor element pad 133 and the mounting pad 15, and thus the former has a higher bonding strength than the latter. The bonding strength may be higher in the former than in the latter due to the difference in the material of the surface.

  The strength (for example, strength in the plane direction, strength against bending, etc.) between the plurality of middle terminals 131 of the middle base 129 is preferably higher than the strength between the plurality of mounting pads 15 of the sensor base 3. For example, because the intermediate substrate 129 is thicker than the sensor substrate 3 and / or the sensor substrate 3 is frame-like (the strength is secured by the base 9 and the mounting arm 10), the intermediate substrate 129 is a plate The intermediate base 129 is stronger than the sensor base 3 due to its shape.

  The lid 115 may be formed of an insulating material such as a resin or a ceramic, or may be formed of a conductive material such as a metal. The lid 115 is joined to the mounting base 111, for example, so as to seal the inside of the recess 119a. The bonding is, for example, seam welding or atomic diffusion bonding. The sealed recess 119a may be evacuated or may be filled with an appropriate gas such as an inert gas (for example, nitrogen).

  As described above, in the present embodiment, the angular velocity sensor 101 includes the sensor element 1 having the sensor base 3 made of a piezoelectric material, and the mounting base 111 having the insulating base 119 made of a material different from the material of the sensor base 3 The intermediate substrate 129 is made of the same material as that of the base 3 and is joined to the sensor element 1 and is also joined to the mounting base 111 to indirectly hold the sensor element 1 on the mounting base 111. .

  Therefore, for example, the sensor base 3 is fixed to the intermediate base 129 having a thermal expansion coefficient equal to that of the sensor base 3, and even if the temperature of both increases, the amount of thermal expansion between the two is equal. It is hard to produce a thermal stress. Also, for example, the thermal stress generated in the mounting substrate 111 is reduced by the stress of the intermediate substrate 129 against it, and then transmitted to the sensor element 1. Therefore, for example, the thermal stress generated in the sensor base 3 is reduced as compared to the case where the intermediate base 129 is not provided. As a result, for example, the change in the vibration characteristic of the sensor base 3 due to the thermal stress is suppressed. That is, the influence of thermal stress on detection accuracy is reduced.

  Further, in the present embodiment, the bonding strength between the intermediate base 129 and the mounting base 111 is higher than the bonding strength between the sensor element 1 and the intermediate base 129.

  Here, the thermal stress of the mounting base 111 is directly applied to the joint between the mounting base 111 and the intermediate base 129, and the heat of the mounting base 111 is connected to the joint between the intermediate base 129 and the sensor element 1. The stress is reduced and transmitted by the stress of the intermediate substrate 129. Therefore, by changing the relative strength of the mounting base 111 relative to the mounting base 111 relatively high by increasing the strength at the joint where the thermal stress of the mounting base 111 is directly applied, the attitude of the sensor element 1 relative to the middle base 129 is suppressed. Therefore, the change of the posture of the sensor element 1 with respect to the mounting substrate 111 can be efficiently suppressed, and the influence of the thermal stress on the detection accuracy can be suppressed. In addition, the intermediate substrate 129 can easily expand the bonding area that may affect the vibration appropriately, as compared with the sensor element 1 in which the vibration characteristics need to be finely adjusted. Thus, the change in the attitude of the sensor element 1 can be suitably suppressed.

  Further, in the present embodiment, the sensor base 3 and the intermediate base 129 are made of single crystals, and are bonded in a state in which the directions of the crystals coincide with each other.

  Therefore, while using a single crystal which is a material suitable as a material of the sensor substrate 3, the difference between the thermal expansion coefficients of the two can be eliminated, and the influence of the thermal stress on the detection accuracy can be reduced. Also, for example, since the single crystal is generally higher in strength than a polycrystal, the effect of alleviating the thermal stress transmitted from the mounting substrate 111 to the sensor element 1 by the intermediate substrate 129 is improved.

  Further, in the present embodiment, the sensor base 3 extends from the base 9 and the base 9 and is in the same plane as the one or more drive arms 11 provided with the excitation electrode 5 and the one or more drive arms 11 from the base 9. And one or more detection arms 13 provided with detection electrodes 7. The insulating base 119 has a first surface (a surface on the positive side in the z-axis direction) on which the plurality of external terminals 125 are provided, and a second surface (the surface on the negative side in the z-axis direction) of the back surface. And the upper surface). The intermediate substrate 129 is a third surface (surface on the positive side in the z-axis direction) opposite to the second surface and joined to the second surface by the bumps 137, and a back surface of the third surface. And a fourth surface (surface on the negative side in the z-axis direction) to which the sensor element 1 is joined by the bumps 139.

  That is, the portion (box-like bottom portion) where the external terminals 125 of the mounting substrate 111 are provided, the intermediate substrate 129, and the sensor element 1 are arranged in a stacked manner in this order. Therefore, for example, as compared with the embodiment in which the sensor element 1 is mounted on the surface of the intermediate substrate 129 on the mounting substrate 111 side (positive side in the z-axis direction) (this embodiment is also included in the present invention) The thermal stress transferred to the sensor element 1 will be reduced over the entire thickness of the intermediate substrate 129. As a result, for example, the effect of reducing the influence of thermal stress on detection accuracy is improved.

  Further, in the present embodiment, the one or more drive arms 11 and the one or more detection arms 13 all extend in a predetermined direction (y-axis direction). The sensor base 3 includes two mounting arms 10 (one positive side in the y-axis direction) extending from the base 9 on both lateral sides of one or more drive arms 11 and one or more detection arms 13 as a whole. 10A and 10C) and two mounting arms 10 (10B and 10D) extending from the base 9 to the other side in the predetermined direction (the negative side in the y-axis direction). It is bonded to the intermediate base 129.

  Therefore, for example, the error in the amount of bumps 139 is smaller than that in a mode in which the mounting arm 10 is not provided and the base 9 is directly bonded to the intermediate substrate 129 by the bumps 139 (this aspect is also included in the present invention). The influence of parallelism on the intermediate substrate 129 of the sensor element 1 is reduced. As a result, detection accuracy is improved. Furthermore, even if the intermediate base 129 is deformed by the thermal stress from the mounting base 111, the deformation is absorbed by the deformation of the mounting arm 10 and is hardly transmitted to the base 9. As a result, the change in the vibration characteristic of the sensor element 1 is suppressed.

  Further, in the present embodiment, the angular velocity sensor 101 includes the mounting base 111 as a part thereof, and includes the package 117 that accommodates the sensor element 1 and the intermediate base 129.

  Therefore, the sensor element 1 and the intermediate base 129 are placed in the same atmosphere surrounded by the package 117, and the difference in the amount of thermal expansion between the two is reduced. This improves the effect of reducing the influence of thermal stress on detection accuracy.

Second Embodiment
FIG. 9 is a cross-sectional view corresponding to FIG. 8 and showing an angular velocity sensor 201 according to the second embodiment.

  In the second embodiment, the same or similar components as or to those of the first embodiment may be denoted by the same reference numerals as those of the first embodiment, and the description may be omitted. . In addition, even when a symbol different from the symbol of the first embodiment is attached to the configuration corresponding to (similar to) the configuration of the first embodiment, the matters not specifically mentioned are the same as the first embodiment. is there.

  The angular velocity sensor 201 does not have the IC 107, and the intermediate member 113 and the external terminal 125 are directly and electrically connected (without the IC 107). The excitation circuit 103 and the detection circuit 105 (IC 107) are provided, for example, on a circuit board (not shown) on which the angular velocity sensor 201 is mounted, and are electrically connected to the external terminal 125.

  Specifically, for example, the insulating base 219 of the package 217 (mounting base 211) has a configuration in which a recess 219a having a flat bottom surface is formed, and an intermediate member pad 123 is provided on the bottom surface. The intermediate member 113 is electrically connected to and fixed to the mounting substrate 211 by bonding the intermediate terminal 131 to the intermediate member pad 123 by the bumps 137 as in the first embodiment. Also, the intermediate member pad 123 and the external terminal 125 are connected by the connection wiring 226 of the mounting base 211. The connection wiring 226 is formed of, for example, a via conductor which penetrates the bottom of the insulating base 219.

  Also in such a configuration, as in the first embodiment, the angular velocity sensor 201 is bonded to the sensor element 1 and is indirectly bonded to the mounting base 211 by being bonded to the mounting base 211. Since the intermediate base 129 is provided, the same effects as in the first embodiment can be obtained. That is, the influence of thermal stress on detection accuracy is reduced.

  The present invention is not limited to the above embodiments, and may be implemented in various aspects.

  The indirect fixing of the sensor element to the mounting base using the intermediate base in the present invention is applicable to any piezoelectric vibration type angular velocity sensor (sensor element). Therefore, the basic configuration of the angular velocity sensor (for example, the number, position and shape of the drive arm and detection arm, and the position and connection relationship of the electrodes) is not limited to those exemplified in the embodiment. For example, as in the embodiment, the angular velocity sensor has a piezoelectric body including one or more drive arms and one or more detection arms extending on opposite sides in the y-axis direction, and unlike the embodiment, the x-axis or z The electrodes and circuitry may be configured to detect rotation of the shaft. Also, for example, the angular velocity sensor has a piezoelectric body including one or more drive arms and one or more detection arms extending on the same side in the y-axis direction, and detects rotation around x-axis, y-axis or z-axis The electrodes and the circuit may be configured to Also, for example, the angular velocity sensor may have a plurality of drive arms and a plurality of detection arms extending radially. The number of drive arms and detection arms may be set appropriately, for example, only one each. Excitation electrodes may be formed in four regions of two side surfaces like the detection electrode of the embodiment on the drive arm, and detection electrodes formed on four side surfaces such as the drive electrode of the embodiment on the detection arm It may be formed. Contrary to the embodiment, a through groove may be formed in the drive arm or a concave groove may be formed in the detection arm. The base may have a rectangular portion and a beam portion extending from the rectangular portion, and the drive arm and the detection arm may extend from the rectangular portion, and the mounting arm may extend from the tip of the beam portion. Sometimes only the rectangular part is referred to as the base, but this is only a matter of definition of the word of the base.

  Also, as described in the embodiment, the angular velocity sensor may or may not include the excitation circuit and / or the detection circuit (IC). The angular velocity sensor may also include other electronic components such as a thermistor in addition to or instead of the excitation circuit and / or the detection circuit. Also, the angular velocity sensor may be one that does not seal the sensor element (without the package). Also, the configuration and shape of the package may be appropriate. For example, a box may be placed on a flat mounting base. Also, the sensor element and the IC may not be stacked, but may be arranged in parallel. The IC may be implemented by bumps.

  The shape of the intermediate substrate is not limited to a rectangular plate. For example, the intermediate base may have a frame shape in plan view. In this case, for example, the opening of the intermediate base can secure a space in which the drive arm and / or the detection arm can vibrate, and can secure a space in which at least a part of an IC or the like is disposed. However, as mentioned in the description of the embodiment, the plate-like shape is preferable from the viewpoint of increasing the strength of the intermediate substrate.

  Not only the sensor element but also other electronic components such as an IC may be fixed to the intermediate substrate. Also, the conductor may not be provided on the intermediate substrate (the intermediate member having the intermediate substrate may not have the conductor). That is, the intermediate member is an electronic component fixed to an intermediate substrate such as a sensor element, and another electronic component (for example, one fixed to a mounting substrate, one fixed to an intermediate substrate, and / or the mounting substrate itself It does not have to have the function of electrically connecting For example, the mounting substrate and the sensor element fixed to the intermediate substrate may be electrically connected to each other by a bonding wire without passing through the intermediate member.

  As understood from the above, in the case where a mounting arm is provided where the tip is joined to the intermediate substrate, the tip may not contribute to the electrical connection with the intermediate substrate. Further, the bonding between the mounting substrate and the intermediate member and the bonding between the intermediate member and the sensor element may be performed by using an insulating adhesive, or may be made solid over the entire surface of the intermediate member.

  DESCRIPTION OF SYMBOLS 1 ... Sensor element, 3 ... Sensor base | substrate piezoelectric material, 5A ... 1st excitation electrode, 5B ... 2nd excitation electrode, 5C ... 3rd excitation electrode, 5D ... 4th excitation electrode, 7A ... 1st detection electrode, 7B ... 2nd Detection electrode, 101 ... angular velocity sensor, 111 ... mounting base, 119 ... insulating base, 125 ... external terminal, 127 ... intermediate base.

Claims (6)

A sensor element having a sensor base made of a piezoelectric material, and an excitation electrode and a detection electrode provided on the sensor base;
A mounting base having an insulating base made of a material different from the material of the sensor base, and a plurality of external terminals provided on the insulating base;
An intermediate base made of the same material as the material of the sensor base and joined to the sensor element and joined to the mounting base to hold the sensor element indirectly on the mounting base;
I have a,
An angular velocity sensor in which the bonding strength between the intermediate base and the mounting base is higher than the bonding strength between the sensor element and the intermediate base . A sensor element having a sensor base made of a piezoelectric material, and an excitation electrode and a detection electrode provided on the sensor base;
A mounting base having an insulating base made of a material different from the material of the sensor base, and a plurality of external terminals provided on the insulating base;
An intermediate base made of the same material as the material of the sensor base and joined to the sensor element and joined to the mounting base to hold the sensor element indirectly on the mounting base;
I have a,
The intermediate substrate is in the form of a substrate facing the mounting substrate and facing the sensor element on the back surface thereof, and joined to the mounting substrate at a plurality of positions surrounding a central portion in plan view of the intermediate substrate An angular velocity sensor which is not joined to the mounting base at the central portion . A sensor element having a sensor base made of a piezoelectric material, and an excitation electrode and a detection electrode provided on the sensor base;
A mounting base having an insulating base made of a material different from the material of the sensor base, and a plurality of external terminals provided on the insulating base;
An intermediate base made of the same material as the material of the sensor base and joined to the sensor element and joined to the mounting base to hold the sensor element indirectly on the mounting base;
I have a,
The intermediate substrate is in the form of a substrate facing the mounting substrate and facing the sensor element on the back surface thereof, and surrounding the region overlapping the central portion of the sensor element in plan view of the intermediate substrate An angular velocity sensor joined to the mounting base at a position and not joined to the mounting base in a region overlapping the central portion . The sensor base includes a base, one or more drive arms extending from the base and provided with the excitation electrode, and from the base in the same plane as the one or more drive arms, the detection electrode being provided Have one or more detection arms,
The insulating substrate has a first surface provided with the plurality of external terminals, and a second surface on the back surface thereof.
The intermediate substrate is a third surface opposite to the second surface and bonded to the second surface by a bump, and a back surface of the third surface, and the sensor element is opposed to the sensor element by a bump The angular velocity sensor according to any one of claims 1 to 3, further comprising a fourth surface joined. The one or more drive arms and the one or more detection arms all extend in a predetermined direction,
The sensor base includes two mounting arms extending from the base to one side in the predetermined direction on both lateral sides of the one or more driving arms and the one or more detection arms, and the other in the predetermined direction from the base The angular velocity sensor according to claim 4, further comprising two mounting arms extending to the side, and being joined to the intermediate base at a tip end side of the four mounting arms. Having said mounting substrate as part thereof, and have a package for housing the sensor element and the intermediate substrate,
The angular velocity sensor according to any one of claims 1 to 5, wherein the sensor base and the intermediate base are made of single crystals and are joined in a state in which the directions of the crystals coincide with each other .

Images