JP2011027562A - Vibration gyro using piezoelectric film - Google Patents

Abstract

A vibrating gyroscope that measures a plurality of rotation axes with a simple and compact structure is provided.
A ring-shaped vibrating body 11 having a uniform plane, a leg portion 15 that flexibly supports the ring-shaped vibrating body, and an upper metal film and a lower metal film that sandwich a piezoelectric film in the thickness direction. And a plurality of electrodes. When one of the drive electrodes 13a that excites the primary vibration of the ring-shaped vibrating body 11 in the vibration mode of cosNθ is used as a reference drive electrode, the other plurality of electrodes 13b,..., 13f are arranged at specific locations. The With this arrangement, the primary vibration of the out-of-plane cos 2θ vibration mode is excited, and the angular velocity of one or two axes is detected using the secondary vibration detection means of the cos 3θ in-plane vibration mode. be able to. In addition, by providing a group of drive electrodes, an increase in amplitude or power saving can be achieved as compared to a group of drive electrodes arranged only at an angle (360 / N) ° in the circumferential direction.
[Selection] Figure 1

Description

  The present invention relates to a vibration gyro using a piezoelectric film, and more specifically to a vibration gyro capable of measuring a change in angular velocity of two axes at the maximum.

  In recent years, vibration gyros using piezoelectric materials have been actively developed. Conventionally, a gyro, in which the vibrator itself is made of a piezoelectric material as described in Patent Document 1, has been developed, and there is also a gyro that uses a piezoelectric film formed on the vibrator. For example, in Patent Document 2, a PZT film, which is a piezoelectric material, is used to excite the primary vibration of a vibrating body, and a part of the gyro distortion caused by Coriolis force generated when an angular velocity is applied to the vibrating body. A technique for detecting the above is disclosed.

  On the other hand, as the size of various devices on which the gyro is mounted is becoming smaller and smaller, the miniaturization of the gyro itself is also an important issue. In order to achieve downsizing of the gyro, it is necessary to remarkably increase the processing accuracy of each member constituting the gyro. Further, it can be said that the industry demands not only miniaturization but also further improvement of performance as a gyro, in other words, detection accuracy of angular velocity. However, the gyro structure disclosed in Patent Document 2 does not satisfy the demands for miniaturization and high performance over the past several years.

  In response to the above technical problems, the applicant of the present invention basically satisfies all the demands for high performance as a vibration gyro while achieving high machining accuracy by performing all manufacturing processes by dry processes. One of the technical ideas is proposed (Patent Document 3).

In addition to the above technical problem, there is an increasing expectation for a vibrating gyroscope that measures angular velocities with respect to rotation of a plurality of axes (for example, Patent Document 4). However, the development of a vibrating gyroscope having a simple structure that enables downsizing is still halfway.
JP-A-8-271258 JP 2000-9473 A Japanese Patent Application No. 2008-28835 JP 2005-529306 Gazette Special Table 2002-509615 Japanese translation of PCT publication No. 2002-510398

  As described above, it is very difficult to simultaneously satisfy the demand for high performance as a gyro while achieving downsizing and high processing accuracy of a vibration gyro using a piezoelectric film. In general, when the gyro is reduced in size, there is a problem that the signal detected by the detection electrode of the gyro becomes weak when an angular velocity is given to the vibrating body. In addition, the vibration gyro described in the above-mentioned Patent Document 4 can measure angular velocities with respect to a plurality of rotation axes, but employs a system that substantially measures a change in capacitance. As shown in FIG. 2 and FIG. 3 of the document, it has a complicated structure in which several electrodes are arranged at different locations from those on the vibrating body. That is, if the vibration gyro can measure the angular velocities with respect to a plurality of rotation axes with a simple structure that enables downsizing, the technical value of the vibration gyro is further increased.

  In addition, as described above, as the vibration gyro using the piezoelectric film progresses in size, it becomes difficult to improve the detection sensitivity as a gyro even without the above-described disturbance. Improving the detection sensitivity while trying to achieve this is one of the main requirements for improving the performance of vibration gyros.

  The present invention greatly contributes to miniaturization and high performance of a vibrating gyroscope using a piezoelectric film capable of measuring an angular velocity with respect to one or a plurality of rotation axes by solving the above technical problem. The inventors conducted intensive research on a structure that solves the above technical problems by causing the piezoelectric film to detect the secondary vibration formed by the excitation of the primary vibration and the Coriolis force. As a result, it has been found that the angular velocity with respect to not only a single rotation axis but also a plurality of rotation axes can be measured by devising the arrangement of various electrodes formed by the piezoelectric film and the structure for supporting the vibrating body. Furthermore, the inventors have found that their arrangement can be achieved by a dry process that can satisfy high processing accuracy. Further, it has been found that by focusing on the driving of the primary vibration, it is possible to improve the detection sensitivity while reducing the size and power consumption. The present invention was created from such a viewpoint. In the present application, the “annular or polygonal vibration gyro” is simply referred to as “ring-shaped vibration gyro”.

One vibrating gyroscope according to the present invention includes a ring-shaped vibrating body having a uniform plane, a leg portion that flexibly supports the ring-shaped vibrating body, and a plane on or above the ring-shaped vibrating body. And a plurality of electrodes formed by at least one of an upper metal film and a lower metal film sandwiching the piezoelectric film in the thickness direction. In addition, the plurality of electrodes includes the following (1) and (2):
(1) When N is a natural number greater than or equal to 2, the primary vibration of the ring-shaped vibrating body is excited in the vibration mode of cosNθ, and arranged at an angle of (360 / N) ° in the circumferential direction. A group of drive electrodes including a drive electrode and at least one drive electrode disposed at any angle (180 / N) ° from each of the drive electrodes;
(2) When one of the aforementioned drive electrodes is a reference drive electrode and S = 0, 1,..., N (hereinafter the same in this paragraph), the angular velocity of the aforementioned ring-shaped vibrating body is The secondary vibration in the vibration mode of cos (N + 1) θ generated at a given time is detected, and an angle [{360 / (N + 1)} × S] ° away from the reference drive electrode, and the reference drive electrode And [{360 / (N + 1)} × {S + (1/2)}] ° apart from a group of detection electrodes including electrodes arranged at at least one of the angles.
Furthermore, each of the aforementioned drive electrodes is disposed in the first electrode arrangement region in the aforementioned plane of the aforementioned ring-shaped vibrator, and each of the aforementioned detection electrodes is disposed from the outer periphery of the ring-shaped vibrator. In the second electrode arrangement region in the plane described above including either or both of the region extending to the vicinity of the outer peripheral edge and the region extending from the inner peripheral edge of the ring-shaped vibrating body to the vicinity of the inner peripheral edge It is arranged so that it is not electrically connected to any of the aforementioned drive electrodes.

  According to this vibrating gyroscope, a voltage is applied to the piezoelectric element on the plane provided on the ring-shaped vibrating body, and the voltage signal generated by the distortion of the piezoelectric element is picked up. Therefore, it is possible to excite primary vibration and detect secondary vibration as a uniaxial angular velocity sensor. That is, in this vibrating gyroscope, the piezoelectric element is not formed on the side surface of the ring-shaped vibrating body, and the vibration that is out of the plane where the piezoelectric element is disposed is formed only by the piezoelectric element formed on the plane of the ring-shaped vibrating body. Not only the primary vibration of the mode (hereinafter also referred to as the out-of-plane vibration mode) is excited, but also the secondary vibration of the vibration mode in the plane (hereinafter also referred to as the in-plane vibration mode) is detected. be able to. In addition, since the piezoelectric element is formed only on the plane of the ring-shaped vibrating body, it becomes possible to process the electrode and the ring-shaped vibrating body with high accuracy using a dry process technique. In addition, this vibration gyro has a degree of freedom that can be applied to the vibration modes of cosNθ and cos (N + 1) θ when N is a natural number of 2 or more by arranging the piezoelectric element in the specific region. ing. In addition, by providing the above-described group of drive electrodes, an increase in amplitude or power saving can be achieved as compared with the group of drive electrodes arranged only at an angle of (360 / N) ° in the circumferential direction. The That is, for example, since the former can obtain a large amplitude even when the same voltage is applied to the latter, the detection sensitivity of the vibration gyro is improved. From another viewpoint, the former electric power required to obtain the amplitude of the primary vibration having the same magnitude as the latter can be suppressed. In all the inventions according to the present application, “flexible” means “to the extent that the vibrating body can vibrate”. Further, in the present application, the expression “an angle away from the reference electrode” is used to describe the arrangement of the electrodes. The angle here is the value of the azimuth angle of each electrode when the azimuth angle of the reference electrode is 0 degree. The azimuth angle of each electrode is an arbitrary point taken at the circumference of the ring-shaped vibrating body or the center of the ring (for example, when the ring-shaped vibrating body is circular, for example, the center of the circle. The center can be referred to as a “reference point”) and can be an azimuth angle of a straight line from the electrode to the electrode. This straight line can be any straight line that passes through each electrode, and typically passes through the graphical center, center of gravity, or any vertex of each electrode and the center point described above. It can be a straight line. For example, an electrode disposed at an angle of 30 ° from the reference drive electrode means that the center of the electrode and the center of the reference drive electrode have an angle of 30 ° with respect to the azimuth angle of the reference electrode. An electrode in an arrangement as described above. Unless otherwise noted, the angle notation is described in the clockwise direction for the direction in which the angle increases, but even if the direction in which the angle increases is set in the counterclockwise direction, as long as the specified angle condition is satisfied. The angle notation is within the scope of the present invention.

Further, in the above-described plurality of electrodes in the uniaxial vibration gyro, when the detection electrode is the first detection electrode, a detection electrode having the following configuration (3) is added as the second detection electrode. For example, it is a great advantage that angular velocity can be detected using in-plane vibration modes of a total of two axes (for example, the X axis and the Y axis). However, the detection electrode having the configuration (4) is disposed on the above-described second electrode arrangement region.
(3) Detect secondary vibrations of the vibration axis at an angle of {90 / (N + 1)} ° with respect to the secondary vibrations described above, and S = 0, 1,..., N (hereinafter, this paragraph) In the case of the same), an angle [{360 / (N + 1)} × {S + (1/4)}] ° away from the above-mentioned reference drive electrode and [{360 / (N + 1) from the reference drive electrode )} × {S + (3/4)}] ° A group of second detection electrodes including electrodes arranged at at least one of the angles separated from each other

Another vibrating gyroscope of the present invention includes a ring-shaped vibrating body having a uniform plane, a leg portion that flexibly supports the ring-shaped vibrating body, and on or above the plane of the ring-shaped vibrating body. And a plurality of electrodes formed by at least one of an upper metal film and a lower metal film sandwiching the piezoelectric film in the thickness direction. In addition, the plurality of electrodes includes the following (1) and (2):
(1) When N is a natural number greater than or equal to 2, the primary vibration of the ring-shaped vibrating body is excited in the vibration mode of cosNθ, and arranged at an angle of (360 / N) ° in the circumferential direction. A group of drive electrodes including a drive electrode and at least one drive electrode disposed at any angle (180 / N) ° from each of the drive electrodes;
(2) When one of the aforementioned drive electrodes is a reference drive electrode and S = 0, 1,..., N (hereinafter the same in this paragraph), the angular velocity of the aforementioned ring-shaped vibrating body is The secondary vibration of the vibration mode of cos (N + 1) θ generated at a given time is detected, and [{360 / (N + 1)} × {S + (1/4)}] ° away from the reference drive electrode A group of detection electrodes comprising electrodes arranged at least one of an angle and an angle [{360 / (N + 1)} × {S + (3/4)}] ° away from the reference drive electrode And have.
Furthermore, each of the aforementioned drive electrodes is disposed in the first electrode arrangement region in the aforementioned plane of the aforementioned ring-shaped vibrator, and each of the aforementioned detection electrodes is disposed from the outer periphery of the ring-shaped vibrator. In the second electrode arrangement region in the plane described above including either or both of the region extending to the vicinity of the outer peripheral edge and the region extending from the inner peripheral edge of the ring-shaped vibrating body to the vicinity of the inner peripheral edge It is arranged so that it is not electrically connected to any of the aforementioned drive electrodes.

  According to this vibrating gyroscope, a voltage is applied to the piezoelectric element on the plane provided on the ring-shaped vibrating body, and the voltage signal generated by the distortion of the piezoelectric element is picked up. Therefore, it is possible to excite primary vibration and detect secondary vibration as a uniaxial angular velocity sensor. In other words, this vibration gyro does not form a piezoelectric element on the side surface of the ring-shaped vibrating body, but uses only the piezoelectric element formed on the plane of the ring-shaped vibrating body, and the primary vibration of the out-of-plane vibration mode. As well as secondary vibrations in the in-plane vibration mode can be detected. In addition, since the piezoelectric element is formed only on the plane of the ring-shaped vibrating body, it becomes possible to process the electrode and the ring-shaped vibrating body with high accuracy using a dry process technique. In addition, this vibration gyro has a degree of freedom that can be applied to the vibration modes of cosNθ and cos (N + 1) θ where N is a natural number greater than or equal to 2 by disposing the piezoelectric element in the specific region. ing. In addition, by providing the above-described group of drive electrodes, an increase in amplitude or power saving can be achieved as compared with the group of drive electrodes arranged only at an angle of (360 / N) ° in the circumferential direction. The That is, for example, since the former can obtain a large amplitude even when the same voltage is applied to the latter, the detection sensitivity of the vibration gyro is improved. From another viewpoint, the former electric power required to obtain the amplitude of the primary vibration having the same magnitude as the latter can be suppressed.

Another vibration gyro according to the present invention includes a ring-shaped vibrating body having a uniform plane, a leg portion that flexibly supports the ring-shaped vibrating body, and the plane of the ring-shaped vibrating body or the And a plurality of electrodes formed by at least one of an upper layer metal film and a lower layer metal film that are placed above and sandwich the piezoelectric film in the thickness direction. In addition, the plurality of electrodes includes the following (1) and (2):
(1) When N is a natural number of 3 or more, the first vibration of the ring-shaped vibrating body is excited in the vibration mode of cosNθ, and arranged at an angle separated by (360 / N) ° in the circumferential direction. A group of drive electrodes including a drive electrode and at least one drive electrode disposed at any angle (180 / N) ° from each of the drive electrodes;
(2) When one of the above-described drive electrodes is a reference drive electrode and S = 0, 1,..., N−2 (hereinafter the same in this paragraph), An angle that detects the secondary vibration of the vibration mode of cos (N−1) θ generated when the angular velocity is given, and is separated from the reference drive electrode by [{360 / (N−1)} × S] °. And a group of detections provided with electrodes arranged at least at any angle between [{360 / (N−1)} × {S + (1/2)}] ° from the reference drive electrode Electrode.
Furthermore, each of the aforementioned drive electrodes is disposed in the first electrode arrangement region in the aforementioned plane of the aforementioned ring-shaped vibrator, and each of the aforementioned detection electrodes is disposed from the outer periphery of the ring-shaped vibrator. In the second electrode arrangement region in the plane described above including either or both of the region extending to the vicinity of the outer peripheral edge and the region extending from the inner peripheral edge of the ring-shaped vibrating body to the vicinity of the inner peripheral edge It is arranged so that it is not electrically connected to any of the aforementioned drive electrodes.

  According to this vibrating gyroscope, a voltage is applied to the piezoelectric element on the plane provided on the ring-shaped vibrating body, and the voltage signal generated by the distortion of the piezoelectric element is picked up. Therefore, it is possible to excite primary vibration and detect secondary vibration as a uniaxial angular velocity sensor. In other words, this vibration gyro does not form a piezoelectric element on the side surface of the ring-shaped vibrating body, but uses only the piezoelectric element formed on the plane of the ring-shaped vibrating body, and the primary vibration of the out-of-plane vibration mode. As well as secondary vibrations in the in-plane vibration mode can be detected. In addition, since the piezoelectric element is formed only on the plane of the ring-shaped vibrating body, it becomes possible to process the electrode and the ring-shaped vibrating body with high accuracy using a dry process technique. Further, in this vibration gyro, the degree of freedom that can be applied to the vibration modes of cosNθ and cos (N−1) θ where N is a natural number greater than or equal to 3 by disposing the piezoelectric element in the specific region. It has. In addition, by providing the above-described group of drive electrodes, an increase in amplitude or power saving can be achieved as compared with the group of drive electrodes arranged only at an angle of (360 / N) ° in the circumferential direction. The That is, for example, since the former can obtain a large amplitude even when the same voltage is applied to the latter, the detection sensitivity of the vibration gyro is improved. From another viewpoint, the former electric power required to obtain the amplitude of the primary vibration having the same magnitude as the latter can be suppressed.

Further, in the above-described plurality of electrodes in the uniaxial vibration gyro, when the detection electrode is the first detection electrode, a detection electrode having the following configuration (3) is added as the second detection electrode. For example, it is a great advantage that angular velocity can be detected using in-plane vibration modes of a total of two axes (for example, the X axis and the Y axis). However, the detection electrode having the configuration (4) is disposed on the above-described second electrode arrangement region.
(3) The secondary vibration of the vibration axis at an angle separated by {90 / (N-1)} ° with respect to the above-described secondary vibration is detected, and S = 0, 1,..., N-2 ( Hereinafter, the same in this paragraph), the angle [{360 / (N−1)} × {S + (1/4)}] ° away from the reference drive electrode and the reference drive electrode [{360 / (N−1)} × {S + (3/4)}] a group of second detection electrodes each having an electrode arranged at at least one of the angles apart from each other

Another vibration gyro according to the present invention includes a ring-shaped vibrating body having a uniform plane, a leg portion that flexibly supports the ring-shaped vibrating body, and the plane of the ring-shaped vibrating body or the And a plurality of electrodes formed by at least one of an upper layer metal film and a lower layer metal film that are placed above and sandwich the piezoelectric film in the thickness direction. In addition, the plurality of electrodes includes the following (1) and (2):
(1) When N is a natural number of 3 or more, the first vibration of the ring-shaped vibrating body is excited in the vibration mode of cosNθ, and arranged at an angle separated by (360 / N) ° in the circumferential direction. A group of drive electrodes including a drive electrode and at least one drive electrode disposed at any angle (180 / N) ° from each of the drive electrodes;
(2) When one of the above-described drive electrodes is a reference drive electrode and S = 0, 1,..., N−2 (hereinafter the same in this paragraph), The secondary vibration in the vibration mode of cos (N−1) θ generated when the angular velocity is given is detected, and {{360 / (N−1)} × {S + (1/4) from the reference drive electrode. )}] [Deg.] Away from the reference drive electrode and [{360 / (N-1)} * {S + (3/4)}] [deg.] Away from the reference drive electrode. And a group of detection electrodes.
Furthermore, each of the aforementioned drive electrodes is disposed in the first electrode arrangement region in the aforementioned plane of the aforementioned ring-shaped vibrator, and each of the aforementioned detection electrodes is disposed from the outer periphery of the ring-shaped vibrator. In the second electrode arrangement region in the plane described above including either or both of the region extending to the vicinity of the outer peripheral edge and the region extending from the inner peripheral edge of the ring-shaped vibrating body to the vicinity of the inner peripheral edge It is arranged so that it is not electrically connected to any of the aforementioned drive electrodes.

  According to this vibrating gyroscope, a voltage is applied to the piezoelectric element on the plane provided on the ring-shaped vibrating body, and the voltage signal generated by the distortion of the piezoelectric element is picked up. Therefore, it is possible to excite primary vibration and detect secondary vibration as a uniaxial angular velocity sensor. In other words, this vibration gyro does not form a piezoelectric element on the side surface of the ring-shaped vibrating body, but uses only the piezoelectric element formed on the plane of the ring-shaped vibrating body, and the primary vibration of the out-of-plane vibration mode. As well as secondary vibrations in the in-plane vibration mode can be detected. In addition, since the piezoelectric element is formed only on the plane of the ring-shaped vibrating body, it becomes possible to process the electrode and the ring-shaped vibrating body with high accuracy using a dry process technique. Further, in this vibration gyro, the degree of freedom that can be applied to the vibration modes of cosNθ and cos (N−1) θ where N is a natural number greater than or equal to 3 by disposing the piezoelectric element in the specific region. It has. In addition, by providing the above-described group of drive electrodes, an increase in amplitude or power saving can be achieved as compared with the group of drive electrodes arranged only at an angle of (360 / N) ° in the circumferential direction. The That is, for example, since the former can obtain a large amplitude even when the same voltage is applied to the latter, the detection sensitivity of the vibration gyro is improved. From another viewpoint, the former electric power required to obtain the amplitude of the primary vibration having the same magnitude as the latter can be suppressed.

It should be noted that the addition of the monitor electrode having the following configuration (4) to the plurality of electrodes in each of the above-described one-axis or two-axis vibration gyros is particularly limited to a miniaturized ring-shaped vibration body. This is a preferred embodiment in that the arrangement of the other electrode group and / or the arrangement of the extraction electrode is facilitated in the planar area.
(4) When M = 0, 1,..., 2N-1 (hereinafter, the same in this paragraph), (180 / N) × {M + (1 / 2)} a group of monitor electrodes arranged at an angle other than an angle apart

Furthermore, the addition of monitor electrodes having the following configuration (4) to the plurality of electrodes in each of the above-described one-axis or two-axis vibration gyros is particularly limited in a miniaturized ring-shaped vibrating body. This is a preferred embodiment in that the arrangement of the other electrode group and / or the arrangement of the extraction electrode is facilitated in the planar area.
(4) When one of the drive electrodes is a reference drive electrode and M = 0, 1,..., N−1 (hereinafter the same in this paragraph), the reference drive electrode is circled. A group of monitor electrodes arranged at an angle of [(360 / N) × {M + (1/2)}] ° in the circumferential direction

  According to one vibration gyro of the present invention, since the piezoelectric element is formed as an electrode on the plane included in the ring-shaped vibrating body and in the specific region, the linear gyroscope is primarily used as a uniaxial or biaxial angular velocity sensor. Vibration excitation and secondary vibration detection are possible. In other words, this vibration gyro does not form a piezoelectric element on the side surface of the ring-shaped vibrating body, but uses only the piezoelectric element formed on the plane of the ring-shaped vibrating body, and the primary vibration of the out-of-plane vibration mode. As well as secondary vibrations in the in-plane vibration mode can be detected. In addition, since the piezoelectric element is formed only on the plane of the ring-shaped vibrating body, it becomes possible to process the electrode and the ring-shaped vibrating body with high accuracy using a dry process technique. In this vibrating gyroscope, the degree of freedom that can be applied to the vibration mode of cosNθ when N is a natural number of 2 or more or 3 or more by arranging piezoelectric elements in the above specific region, or cos ( N + 1) [theta] or cos (N-1) [theta] has a degree of freedom applicable. In addition, by providing the above-described group of drive electrodes, an increase in amplitude or power saving can be achieved as compared with the group of drive electrodes arranged only at an angle of (360 / N) ° in the circumferential direction. The

It is a front view of the structure which plays the central role of the ring-shaped vibrating gyroscope in one embodiment of the present invention. It is AA sectional drawing of FIG. It is sectional drawing which shows the process of the one part manufacturing process of the ring-shaped vibrating gyroscope in one embodiment of this invention. It is sectional drawing which shows the process of the one part manufacturing process of the ring-shaped vibrating gyroscope in one embodiment of this invention. It is sectional drawing which shows the process of the one part manufacturing process of the ring-shaped vibrating gyroscope in one embodiment of this invention. It is sectional drawing which shows the process of the one part manufacturing process of the ring-shaped vibrating gyroscope in one embodiment of this invention. It is sectional drawing which shows the process of the one part manufacturing process of the ring-shaped vibrating gyroscope in one embodiment of this invention. It is sectional drawing which shows the process of the one part manufacturing process of the ring-shaped vibrating gyroscope in one embodiment of this invention. It is a front view of the structure which plays the central role of the ring-shaped vibrating gyroscope in other embodiment of this invention. It is a front view of the structure which plays the central role of the ring-shaped vibrating gyroscope in other embodiment of this invention. It is sectional drawing equivalent to FIG. 2 of the structure which plays the central role of the ring-shaped vibrating gyroscope in other embodiment of this invention. It is a front view of the structure which plays the central role of the ring-shaped vibrating gyroscope in other embodiment of this invention. It is BB sectional drawing of FIG. It is a front view of the structure which plays the central role of the ring-shaped vibrating gyroscope in other embodiment of this invention. It is CC sectional drawing of FIG. It is a figure which illustrates notionally the primary vibration of the vibration mode of cos2 (theta) of an out-of-plane in one Embodiment of this invention. It is a figure which illustrates notionally the secondary vibration of the vibration mode of in-plane cos3 (theta) in case angular velocity is added around the X-axis in one Embodiment of this invention. It is a figure which illustrates notionally the secondary vibration of the vibration mode of in-plane cos3 (theta) in case angular velocity is added around the Y-axis in one Embodiment of this invention. It is a figure which illustrates notionally the primary vibration of the vibration mode of cos3 (theta) of the out-of-plane in other embodiment of this invention. It is a figure which illustrates notionally the primary vibration of the vibration mode of in-plane cos2 (theta) in case angular velocity is added around the X-axis in other embodiment of this invention. It is a figure which illustrates notionally the primary vibration of the vibration mode of in-plane cos2 (theta) in case angular velocity is added around the Y-axis in other embodiment of this invention. It is a front view of the structure which plays the central role of the ring-shaped vibrating gyroscope in other embodiment of this invention. It is a front view of the structure which plays the central role of the ring-shaped vibrating gyroscope in other embodiment of this invention. It is a front view of the structure which plays the central role of the ring-shaped vibrating gyroscope in other embodiment of this invention. It is a front view of the structure which plays the central role of the ring-shaped vibrating gyroscope in other embodiment of this invention. It is a front view of the structure which plays the central role of the ring-shaped vibrating gyroscope in other embodiment of this invention. It is a front view of the structure which plays the central role of the ring-shaped vibrating gyroscope in other embodiment of this invention.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this description, common parts are denoted by common reference symbols throughout the drawings unless otherwise specified. In the drawings, the elements of the present embodiment are not necessarily shown to scale.

<First Embodiment>
FIG. 1 is a front view of a structure that plays a central role in a ring-shaped vibrating gyroscope 100 that measures biaxial angular velocities in this embodiment. FIG. 2 is a cross-sectional view taken along the line AA of FIG. For convenience of explanation, the X axis and the Y axis are shown in FIG.

  As shown in FIGS. 1 and 2, the ring-shaped vibrating gyroscope 100 of this embodiment is roughly classified into three configurations. The first configuration includes a silicon oxide film 20 on an upper plane (hereinafter referred to as an upper surface) of a ring-shaped vibrating body 11 formed from a silicon substrate 10, and a piezoelectric film 40 is further formed on the lower layer metal. In this configuration, a plurality of electrodes 13 a to 13 f are formed by being sandwiched between the film 30 and the upper metal film 50. In the present embodiment, the outer end portion or the inner end portion of the upper metal film 50 constituting the plurality of electrodes 13b to 13e is about from the outer peripheral edge or the inner peripheral edge of the ring-shaped vibrating body 11 having a ring-shaped plane having a width of about 40 μm. It is formed inside 1 μm and its width is about 12 μm. Further, of the upper metal film 50, the four electrodes 13a and 13f are formed so as to include the center line, and the width thereof is about 12 μm. The twelve electrodes are formed outside the line connecting the centers of both ends of the width of the ring-shaped plane that is the upper surface of the ring-shaped vibrating body 11 (hereinafter simply referred to as the center line), and the other twelve electrodes. The electrode is arranged inside the center line.

  By the way, in the present embodiment, the primary vibration of the ring-shaped vibrating gyroscope 100 is excited in the vibration mode of cos 2θ of FIG. 11A out-of-plane. The vibration modes of the secondary vibration of the present embodiment are the X-axis cos 3θ in-plane vibration mode shown in FIG. 11B and the Y-axis cos 3θ in-plane vibration mode shown in FIG. 11C.

  Accordingly, the breakdown of the plurality of electrodes 13a to 13f is as follows. First, two drive electrodes 13a, 13a arranged at an angle of (360/2) ° in the circumferential direction, that is, 180 ° apart, and (180/2) °, that is, 90 ° apart from each of the drive electrodes. One drive electrode 13a arranged at an angle is arranged. Here, for convenience of drawing, the AC power supply connected to the drive electrodes 13a, 13a, 13a is omitted. In addition, when one of the three drive electrodes 13a, 13a, 13a described above (for example, the drive electrode 13a in the 12 o'clock direction of the timepiece in FIG. 1) is used as a reference electrode, the drive electrode 13a One monitor electrode 13f is arranged at an angle of 270 ° in the circumferential direction. Further, when an angular velocity around the X axis is given to the ring-shaped vibrating gyroscope 100 when the plane on which the piezoelectric element on the ring-shaped vibrating body is arranged, in other words, the paper surface in FIG. The first detection electrodes 13b and 13c that detect secondary vibrations generated in the circumferential direction are circumferentially away from the reference electrode at angles of 0 °, 60 °, 120 °, 180 °, 240 °, and 300 °. Be placed. Similarly, the second detection electrodes 13d and 13e for detecting secondary vibration generated when an angular velocity around the Y axis is applied to the ring-shaped vibration gyro 100 are 30 ° and 90 ° in the circumferential direction from the reference electrode. They are arranged at angles separated by °, 150 °, 210 °, 270 °, and 330 °. Since the monitor electrode 13f is used for monitoring the amplitude and frequency of the excited primary vibration, it is sufficient to use a number that can achieve the purpose, and it is not necessary to use a plurality.

  In the present embodiment, the lower metal film 30 and the upper metal film 50 have a thickness of 100 nm, and the piezoelectric film 40 has a thickness of 3 μm. The thickness of the silicon substrate 10 is 100 μm.

  In the present embodiment and other embodiments described later, the region where each electrode is arranged is classified into two. One is a first detection electrode disposed in a region from the outer periphery of the upper surface of the ring-shaped vibrating body 11 to the vicinity of the outer periphery and / or a region from the inner periphery to the vicinity of the inner periphery. 13b and 13c and the second detection electrodes 13d and 13e. This is the second electrode arrangement region. The other is an area on the upper surface of the ring-shaped vibrating body 11 where the drive electrodes 13a and 13a arranged so as not to be in electrical contact with the second electrode arrangement area are formed. This is defined as a first electrode arrangement region. More specifically, the first detection electrodes 13b and 13c and the second detection electrodes 13d and 13e are arranged so as not to be electrically connected to any of the three drive electrodes 13a, 13a, and 13a.

  The second configuration is leg portions 15,..., 15 connected to a part of the ring-shaped vibrating body 11. The leg portions 15,..., 15 are also formed from the silicon substrate 10. Further, on the leg portions 15,..., The above-described silicon oxide film 20, lower metal film 30, and piezoelectric film 40 that are continuous with those on the ring-shaped vibrating body 11 are formed on the leg portions 15. .. formed on the entire top surface of 15. Further, on the center line of the upper surface of the piezoelectric film 40, an upper metal film 50 that is the extraction electrodes 14,...

  In the present embodiment, among the 24 leg portions 15,..., 15, a plurality of lead electrodes 14 are formed on 12 leg portions 15,. These secure a route from the outer peripheral edge of the ring-shaped vibrating body 11 to the vicinity of the outer peripheral edge, and a path for drawing out from each electrode arranged to include the center line to the electrode pad 18 on the column 19. Was created to do. In particular, in this embodiment, lead electrodes 14 and 14 are formed from both end portions of the second detection electrodes 13b and 13d in order to eliminate the bias of the electric signals from the second detection electrodes 13b and 13d. Even when the extraction electrodes 14 and 14 are formed only from one side of the second detection electrodes 13b and 13d, the function as a vibrating gyroscope is not lost.

  A third configuration is a support column 19 formed from the silicon substrate 10 connected to the above-described leg portions 15,. In the present embodiment, the support column 19 is connected to a package portion of the ring-shaped vibrating gyroscope 100 (not shown) and serves as a fixed end. The support column 19 includes electrode pads 18,. Further, as shown in FIG. 2, on the upper surface of the support column 19, except for the fixed potential electrode 16 that is a ground electrode, the above-described silicon oxide film 20 that is continuous with those on the leg portions 15,. A metal film 30 and a piezoelectric film 40 are formed. Here, the lower metal film 30 formed on the silicon oxide film 20 serves as the fixed potential electrode 16. Further, on the upper surface of the piezoelectric film 20 formed above the support column 19, the above-described lead electrodes 14,..., 14 and electrode pads 18 that are continuous with those on the leg portions 15,. ..., 18 are formed.

  Next, a method for manufacturing the ring-shaped vibrating gyroscope 100 of this embodiment will be described with reference to FIGS. 3A to 3F. 3A to 3F are cross-sectional views corresponding to a part of the range in FIG.

  First, as shown in FIG. 3A, a silicon oxide film 20, a lower metal film 30, a piezoelectric film 40, and an upper metal film 50 are stacked on a silicon substrate 10. Each of the aforementioned films is formed by a known film forming means. In this embodiment, the silicon oxide film 20 is a thermal oxide film by a known means. The lower metal film 30, the piezoelectric film 40, and the upper metal film 50 are all formed by a known sputtering method. In addition, formation of these films | membranes is not limited to the above-mentioned example, It can form also by another well-known means.

Next, a part of the upper metal film 50 is etched. In this embodiment, after forming a known resist film on the upper metal film 50, the upper metal film 50 shown in FIG. 3B is formed by performing dry etching based on the pattern formed by the photolithography technique. The Here, the dry etching of the upper metal film 50 is performed under known reactive ion etching (RIE) conditions using argon (Ar) or a mixed gas of argon (Ar) and oxygen (O ₂ ).

Thereafter, as shown in FIG. 3C, a part of the piezoelectric film 40 is etched. First, as described above, the piezoelectric film 40 is dry-etched based on the resist film patterned by the photolithography technique. Incidentally, the dry etching of the piezoelectric film 40 of the present embodiment, using argon (Ar) and a mixed gas of _C 2 _{F 6} gas, or argon (Ar) and _C 2 _{F 6} gas and CHF ₃ gas mixed gas This is performed under known reactive ion etching (RIE) conditions.

Subsequently, as shown in FIG. 3D, a part of the lower metal film 30 is etched. In the present embodiment, dry etching is again performed using a resist film patterned by a photolithography technique so that the fixed potential electrode 16 using the lower metal film 30 is formed. In the present embodiment, the fixed potential electrode 16 is used as a ground electrode. Note that the dry etching of the lower metal film 30 of the present embodiment is performed under known reactive ion etching (RIE) conditions using argon (Ar) or a mixed gas of argon (Ar) and oxygen (O ₂ ).

  By the way, in this embodiment, since the subsequent silicon oxide film 20 and the silicon substrate 10 are continuously etched using the re-formed resist film as an etching mask, the thickness of the resist film is about 4 μm. Is formed. However, even if this resist film disappears during the etching of the silicon substrate 10, the etching rate selectivity with respect to the etchant used for the silicon substrate 10 works favorably. 50, the performance of the piezoelectric film 40, and the lower metal film 30 are not substantially affected. That is, in this embodiment, since the ring-shaped vibrating body 11 is formed from a silicon substrate, a known silicon trench etching technique having a sufficiently high selectivity with respect to the resist film can be applied. Even if the resist film disappears, the upper metal film or piezoelectric film under the resist film has a sufficient selection ratio to serve as a mask for etching silicon.

Next, as shown in FIGS. 3E and 3F, the silicon oxide film 20 and the silicon substrate 10 are dry-etched using the resist film for etching the lower metal film 30 as described above. The dry etching of the silicon oxide film 20 of the present embodiment was performed under known reactive ion etching (RIE) conditions using argon (Ar) or a mixed gas of argon (Ar) and oxygen (O ₂ ). In addition, a known silicon trench etching technique is applied to the dry etching conditions of the silicon substrate 10 of the present embodiment. Here, the silicon substrate 10 is etched through. Therefore, in the dry etching described above, a protective substrate for preventing the stage on which the silicon substrate 10 is placed from being exposed to plasma during penetration is attached to the lower layer of the silicon substrate 10 with grease having excellent heat conductivity. Done. Therefore, for example, in order to prevent the surface in the direction perpendicular to the thickness direction of the silicon substrate 10 after the penetration, in other words, the etching side surface from being eroded, the dry etching technique described in JP-A-2002-158214 is employed. This is a preferred embodiment.

  As described above, after the central structure of the ring-shaped vibrating gyroscope 100 is formed by etching the silicon substrate 10 and each film laminated on the silicon substrate 10, the process of accommodating the package in a known means, and The ring-shaped vibrating gyroscope 100 is formed through the wiring process. Therefore, according to this vibrating gyroscope 100, the piezoelectric element is not formed on the side surface of the ring-shaped vibrating body 11, and only the piezoelectric element formed on the plane of the ring-shaped vibrating body 11 is used to generate a primary out-of-plane primary. It becomes possible to excite vibration and to detect a secondary vibration of a maximum of two axes in-plane. As a result, the vibrating gyroscope 100 can be manufactured using the dry process technology that can be mass-produced with high accuracy and low cost.

  Next, the operation of each electrode provided in the ring-shaped vibrating gyroscope 100 will be described. As described above, in this embodiment, the primary vibration of the out-of-plane cos 2θ vibration mode is excited. Since the fixed potential electrode 16 is grounded, the lower electrode film 30 formed continuously with the fixed potential electrode 16 is uniformly at 0V.

First, an AC voltage of 1 V _P-0 is applied to the three drive electrodes 13 a, 13 a, and 13 a. However, in FIG. 1, the phase of the voltage applied to the driving electrode 13a in the 3 o'clock direction of the timepiece is opposite to the phase of the voltage applied to the other two driving electrodes 13a and 13a. As a result, the piezoelectric film 40 expands and contracts to excite primary vibration. Here, in the present embodiment, the upper metal film 50 is formed so as to include the center line of the ring-shaped vibrating body 11 in plan view. This is because it is difficult to excite secondary vibration, which is an in-plane vibration mode, due to distortion of the piezoelectric film. However, if the resonance frequencies of the ring-shaped vibrating body 11 of the primary vibration and the secondary vibration are different, the drive electrodes 13a may be arranged so as not to include the center line.

  As described above, in the present embodiment, two drive electrodes 13a and 13a disposed at an angle of (360/2) ° in the circumferential direction, that is, 180 ° apart, and each of these drive electrodes (180/2). ) °, that is, one drive electrode 13a arranged at an angle of 90 °. Therefore, the ring-shaped vibrating gyroscope 100 according to the present embodiment has an amplitude larger than that of the ring-shaped vibrating gyroscope including a group of drive electrodes arranged only at an angle of (360/2) °, that is, 180 ° in the circumferential direction. Increase or power saving is achieved. That is, for example, since the former can obtain a large amplitude even when the same voltage is applied to the latter, the detection sensitivity of the vibration gyro is improved. From another point of view, the former power required to obtain the amplitude of the primary vibration of the same magnitude as the latter can be suppressed.

  Next, the monitor electrode 13f shown in FIG. 1 detects the amplitude and resonance frequency of the primary vibration described above, and transmits a signal to a known feedback control circuit (not shown). The feedback control circuit of the present embodiment controls the frequency of the AC voltage applied to the drive electrodes 13a, 13a, and 13a so that the natural frequency of the ring-shaped vibrating body 11 coincides with the amplitude of the ring-shaped vibrating body 11. Control is performed using the signal of the monitor electrode 13f so as to have a certain value. As a result, the ring-shaped vibrating body 11 maintains a constant vibration.

  Here, a case where an angular velocity is applied around the X-axis after the above-described primary vibration is excited will be described. In this case, the secondary vibration in the vibration mode of in-plane cos 3θ shown in FIG. 11B is generated.

  This secondary vibration is detected by six detection electrodes (first detection electrodes) 13b, ..., 13b and another six detection electrodes (first detection electrodes) 13c, ..., 13c. In the present embodiment, as shown in FIG. 1, each of the detection electrodes 13b and 13c is disposed corresponding to the vibration axis of the in-plane secondary vibration. In the present embodiment, each of the detection electrodes 13b and 13c described above has a center line on the upper surface of the ring-shaped vibrating body 11 so that the secondary vibration to be detected, that is, the in-plane vibration mode, can be detected most easily. The outer side and the inner side are arranged. In the present application, the vibration axis means an orientation in which the amplitude of the described vibration is the largest, and is indicated by a direction on the ring-shaped vibrating body.

  In the present embodiment, the arrangement of the detection electrodes 13b and 13c reverses the sign of the electrical signals of the detection electrodes 13b and 13c caused by the in-plane secondary vibration excited by the angular velocity. Therefore, the difference between the electrical signals of the detection electrodes 13b and 13c is calculated in an arithmetic circuit which is a known difference circuit. As a result, the detection signal has about twice the detection capability as compared with the case of either one of the detection electrodes.

  Next, a case where an angular velocity is applied around the Y axis after the above-described primary vibration is excited will be described. In this case, the secondary vibration in the in-plane cos 3θ vibration mode shown in FIG. 11C occurs.

  This secondary vibration is detected by six detection electrodes (second detection electrodes) 13d,..., 13d and another six detection electrodes (second detection electrodes) 13e,. In the present embodiment, as shown in FIG. 1, the detection electrodes 13d and 13e are arranged corresponding to the vibration axes of the in-plane secondary vibration, respectively. In the present embodiment, each of the detection electrodes 13d and 13e described above also has a center line on the upper surface of the ring-shaped vibrating body 11 so that the secondary vibration to be detected, that is, the in-plane vibration mode, can be detected most easily. The outer side and the inner side are arranged.

  In the present embodiment, the arrangement of the detection electrodes 13b and 13c reverses the sign of the electrical signals of the detection electrodes 13d and 13e generated by the in-plane secondary vibration excited by the angular velocity. Therefore, in the same manner as described above, the difference between the electrical signals of the detection electrodes 13d and 13e is calculated in an arithmetic circuit that is a known difference circuit. As a result, the detection signal has about twice the detection capability as compared with the case of either one of the detection electrodes.

  By the way, in the first embodiment described above, for the sake of convenience, the names of the first detection electrode and the second detection electrode are given to the detection electrodes that detect each of the two axes that are targets for detecting the angular velocity. As the name of the detection electrode for the axis, any one non-overlapping name of the first detection electrode and the second detection electrode may be given.

<Modification Example (1) of First Embodiment>
FIG. 4 is a front view of a structure that plays a central role in the ring-shaped vibrating gyroscope 200 obtained by modifying a part of the first embodiment.

  The ring-shaped vibrating gyroscope 200 of the present embodiment has the same configuration as the ring-shaped vibrating gyroscope 100 of the first embodiment, except for the upper metal film 50 in the first embodiment. The manufacturing method is the same as that of the first embodiment except for a part. Furthermore, the vibration mode of the primary vibration and the vibration mode of the secondary vibration in the present embodiment are the same vibration modes as those in the first embodiment. Therefore, the description which overlaps with 1st Embodiment may be abbreviate | omitted.

  As shown in FIG. 4, in the ring-shaped vibrating gyroscope 200 of this embodiment, each detection electrode 13b, 13c, 13d, 13e is arranged one by one. Even with such an arrangement of the detection electrodes, the effect of the present invention is substantially achieved. That is, the presence of the detection electrodes 13b, 13c, 13d, and 13e makes it possible to detect an angular velocity using a biaxial (X axis and Y axis) in-plane vibration mode. Since there is only one detection electrode 13b, 13c, 13d, 13e having the same electrode area as that of the first embodiment, the detection capability is inferior to that of the first embodiment. In FIG. 4, AC power supplies 12 and 12 that are not shown in FIG. 1 for convenience are displayed. The actual AC power supplies 12 and 12 are applied to the three drive electrodes 13a, 13a, and 13a via the electrode pads 18 connected to the conductive wires. In the present embodiment and other embodiments, the description will be made. For convenience, it can be omitted.

  In this embodiment as well, two drive electrodes 13a and 13a arranged at an angle of (360/2) ° in the circumferential direction, that is, 180 ° apart, and (180/2) ° from each of these drive electrodes. That is, one drive electrode 13a disposed at an angle of 90 ° is disposed. Therefore, the ring-shaped vibrating gyroscope 200 according to the present embodiment has an amplitude larger than that of the ring-shaped vibrating gyroscope including a group of drive electrodes arranged only at an angle of (360/2) °, that is, 180 ° in the circumferential direction. Increase or power saving is achieved.

  Further, in the present embodiment, since each electrode is unevenly distributed, there is a leg portion 15 where the extraction electrode 14 is not formed, but the present embodiment is not limited to this. For example, even if the leg portion 15 where the extraction electrode 14 is not formed is eliminated, the same effect as that of the present embodiment is achieved. However, since the absence of the disordered leg portions 15 may hinder the uniform vibration of the ring-shaped vibrating body 11, a structure in which only the leg portions 15 located at positions allocated so as to be separated by a uniform angle are eliminated.

<Modification (1) of the first embodiment>
FIG. 5 is a front view of a structure that plays a central role in a ring-shaped vibrating gyroscope 300 obtained by modifying a part of the first embodiment.

  The ring-shaped vibrating gyroscope 300 of the present embodiment has the same configuration as the ring-shaped vibrating gyroscope 100 of the first embodiment, except for the upper metal film 50 in the first embodiment. The manufacturing method is the same as that of the first embodiment except for a part. Furthermore, the vibration mode of the primary vibration and the vibration mode of the secondary vibration in the present embodiment are the same vibration modes as those in the first embodiment. Therefore, the description which overlaps with 1st Embodiment may be abbreviate | omitted.

  As shown in FIG. 5, on the ring-shaped vibrating gyroscope 300 of this embodiment, there are three drive electrodes 13a, 13a, 13a, one monitor electrode 13f, and a first detection electrode for measuring the X-axis angular velocity. Only one of the electrodes 13b and one electrode 13e of the second electrode for Y-axis angular velocity measurement are formed. A part of each drive electrode 13a is arranged not only from the center line but also from the center line to the vicinity of the inner peripheral edge. Furthermore, each detection electrode 13b, 13e has its electrode region extending from the central line to the vicinity of the outer peripheral edge or from the central line to the vicinity of the inner peripheral edge. Even with such an arrangement of the detection electrodes, substantially the same effect as in the first embodiment can be obtained. That is, at least one of the first X-axis detection electrodes 13b and 13c included in the first embodiment and at least one of the second Y-axis detection electrodes 13d and 13e are present. By doing so, it is possible to detect the angular velocity using the biaxial (X-axis and Y-axis) in-plane vibration modes.

  By the way, each drive electrode 13a is preferably arranged so as to excite only the primary vibration of the out-of-plane vibration mode and hardly excite the secondary vibration which is the in-plane vibration mode. This is because if the secondary vibration is generated in a state where the angular velocity is not applied, it becomes a factor for generating the zero point output of the vibration gyro 300. In the in-plane vibration mode, the drive electrodes 13a are arranged so as to include the center line, so that it is difficult to excite the secondary vibration that is the in-plane vibration mode because the distortion near the center line is small. Therefore, this is a preferred embodiment. In the in-plane vibration mode, the direction of distortion is reversed with the center line as a boundary. Therefore, it is a more preferable aspect that the drive electrodes 13a are arranged symmetrically with respect to the center line. Further, even if the plurality of drive electrodes 13a are not arranged so as to be the target with respect to the center line, the arrangement of the drive electrodes 13a that are difficult to excite the in-plane vibration mode according to the vibration mode to be employed is There are various. Therefore, as described above, the first electrode arrangement region in which each drive electrode 13a is arranged is defined as a region on the upper surface of the ring-shaped vibrating body 11 that is not in electrical contact with the second electrode arrangement region. More specifically, the detection electrodes 13b and 13e are arranged so as not to be electrically connected to any of the three drive electrodes 13a, 13a, and 13a.

  Each of the detection electrodes 13b and 13e is arranged so that the electrode region includes the center line, but only the region from the outer peripheral edge of the ring-shaped vibrating body 11 to the vicinity of the outer peripheral edge and / or the region thereof. The arrangement of only the region from the inner peripheral edge to the vicinity of the inner peripheral edge improves the detection sensitivity of the vibration mode of the in-plane secondary vibration. This is because, in the in-plane vibration mode, the distortion direction is reversed with the center line as a boundary, so that the signal from the electrode region existing beyond the center line weakens the strength of the detection signal.

  By the way, in this embodiment, since the difference circuit employ | adopted as 1st Embodiment becomes unnecessary, the circuit is simplified. In the present embodiment, in particular, the area of one drive electrode 13a is formed larger than that of the first embodiment. Thus, the power required for driving can be suppressed by increasing the area of the drive electrode 13a.

  In this embodiment as well, two drive electrodes 13a and 13a arranged at an angle of (360/2) ° in the circumferential direction, that is, 180 ° apart, and (180/2) ° from each of these drive electrodes. That is, one drive electrode 13a disposed at an angle of 90 ° is disposed. Therefore, the ring-shaped vibrating gyroscope 300 according to the present embodiment has an amplitude larger than that of the ring-shaped vibrating gyroscope including a group of drive electrodes arranged only at an angle of (360/2) °, that is, 180 ° in the circumferential direction. Increase or power saving is achieved.

  In the present embodiment, the area of the monitor electrode 13f is the same as that of the first embodiment, but is not limited to this. It is a preferable aspect that the detection capability is improved by increasing the area of the monitor electrode.

  Further, in the present embodiment, since each electrode is unevenly distributed, there is a leg portion 15 where the extraction electrode 14 is not formed, but the present embodiment is not limited to this. For example, even if the leg portion 15 where the extraction electrode 14 is not formed is removed, the same effect as the present embodiment can be obtained. However, since the absence of the disordered leg portion 15 may hinder the uniform vibration of the ring-shaped vibrating body 11, a structure in which only the leg portions 15 at positions allocated so as to be separated by a uniform angle are removed is preferable. .

<Modification (3) of the first embodiment>
FIG. 6 is a cross-sectional view corresponding to FIG. 2 of a structure that plays a central role in a ring-shaped vibrating gyroscope 400 obtained by modifying a part of the first embodiment.

  In the present embodiment, as shown in FIG. 6, the piezoelectric film 40 is etched in accordance with a region where the upper metal film 50 is substantially formed. For this reason, the AC voltage applied to the upper metal film 50 is applied only vertically downward without being affected by the region where the lower metal film 30 is formed. Transmission is prevented. In the present embodiment, after the dry etching step of the upper metal film 50, the remaining resist film on the upper metal film 50 or the metal film 50 itself is used as an etching mask, and then the dry etching is performed under the same conditions as in the first embodiment. By performing the etching, the above-described piezoelectric film 40 is formed. Further, as shown in FIG. 6, in this embodiment, the piezoelectric film 40 is etched in an inclined shape (for example, an inclination angle is 75 °). However, in the present application, the piezoelectric film 40 having a steep inclination as shown in FIG. 6 is not visually recognized in contrast with other regions in the plan view of the ring-shaped vibrating gyroscope 400 shown in FIG. Handled. In addition, the aspect in which the piezoelectric film 40 disclosed in this embodiment is etched can be applied to at least all the embodiments of the present application.

<Modification (4) of the first embodiment>
In the first embodiment and the modifications (1) to (3) described above, the structure of the vibrating gyroscope capable of detecting the biaxial angular velocity is described. However, each detection electrode for detecting the uniaxial angular velocity is described. Is also derived from the first embodiment.

  For example, among the first detection electrodes and the second detection electrodes 13b, 13c, 13d, and 13e, only the first detection electrodes 13b and 13c for measuring the X-axis angular velocity are arranged on the ring-shaped vibrating body 11, A vibrating gyroscope that detects a uniaxial angular velocity is manufactured. That is, by selecting a detection electrode corresponding to one of the first detection electrode and the second detection electrode, it is possible to obtain a vibration gyro that detects the angular velocity of one axis. For example, it has already been described that the effect of the present invention can be substantially achieved by arranging only one first detection electrode (for example, 13b) among the first detection electrodes 13b and 13c. It is as follows.

<Second Embodiment>
FIG. 7 is a front view of a structure that plays a central role in the ring-shaped vibrating gyroscope 500 of the present embodiment. 8 is a cross-sectional view taken along the line BB in FIG.

  As shown in FIGS. 7 and 8, the ring-shaped vibrating gyroscope 500 according to the present embodiment includes a plurality of electrodes 13 a to 13 f as with the ring-shaped vibrating gyroscope 100 according to the first embodiment. In the present embodiment, all the electrodes are arranged outside the center line or inside the center line.

  By the way, in this embodiment, the primary vibration of the ring-shaped vibrating gyroscope 500 is excited in the out-of-plane cos 3θ vibration mode shown in FIG. 12A. On the other hand, the vibration mode of the secondary vibration of the present embodiment is an in-plane cos 2θ vibration mode. Accordingly, the breakdown of the plurality of electrodes 13a to 13f is as follows. First, two drive electrodes 13a and 13a disposed at an angle of (360/3) ° in the circumferential direction, that is, 120 ° apart, and (180/3) °, that is, 60 ° apart from each of the drive electrodes. Two drive electrodes 13a, 13a arranged at a certain angle are arranged. When one drive electrode 13a (for example, the drive electrode 13a in the 12 o'clock direction in FIG. 9) of the four drive electrodes 13a,. Two monitor electrodes 13f and 13f are arranged at an angle of 120 ° and 300 ° in the circumferential direction from 13a. Further, when the plane on which the piezoelectric element on the ring-shaped vibrating body 11 is arranged, in other words, when the paper surface in FIG. 9 is the XY plane as shown in the figure, the first angular velocity detection around the X axis is detected. The detection electrodes 13b and 13c are arranged at angles of 0 °, 90 °, 180 °, and 270 ° in the circumferential direction from the reference electrode. Similarly, the second detection electrodes 13d and 13e for detecting the angular velocity around the Y axis are arranged at angles of 45 °, 135 °, 225 °, and 315 ° in the circumferential direction from the reference electrode.

  Even with such an arrangement of the detection electrodes, the effect of the present invention is substantially achieved. That is, the presence of the detection electrodes 13b, 13c, 13d, and 13e makes it possible to detect the angular velocity using the biaxial in-plane cos 2θ vibration mode. Specifically, the X-axis in-plane cos 2θ vibration mode is shown in FIG. 12B, and the Y-axis in-plane cos 2θ vibration mode is shown in FIG. 12C.

  In the present embodiment, the four drive electrodes 13a,..., 13a are arranged in a region from the outer peripheral edge of the ring-shaped vibrating body 11 to the vicinity of the outer peripheral edge, but the present invention is not limited to this. Each drive electrode 13a is preferably arranged so as to excite only the primary vibration of the out-of-plane vibration mode and hardly excite the secondary vibration which is the in-plane vibration mode. This is because if the secondary vibration is generated in a state where the angular velocity is not applied, it becomes a factor for generating the zero point output of the vibration gyro 500. Therefore, in the in-plane vibration mode, each drive electrode 13a is disposed so as to include the center line, and thus the secondary vibration that is the in-plane vibration mode is excited by the small distortion near the center line. Since it becomes difficult, it becomes a preferable aspect. In the in-plane vibration mode, the direction of distortion is reversed with the center line as a boundary. Therefore, it is a more preferable aspect that the drive electrodes 13a are arranged symmetrically with respect to the center line.

  In this embodiment, (360/3) ° in the circumferential direction, that is, two drive electrodes 13a and 13a disposed at an angle of 120 ° and (180/3) ° from each of these drive electrodes. That is, two drive electrodes 13a and 13a arranged at an angle of 60 ° are arranged. Therefore, the ring-shaped vibrating gyroscope 500 according to the present embodiment has an amplitude larger than that of the ring-shaped vibrating gyroscope including a group of drive electrodes arranged only at an angle of (360/3) °, that is, 120 ° in the circumferential direction. Increase or power saving is achieved.

<Modification of Second Embodiment>
FIG. 9 is a front view of a structure that plays a central role in a ring-shaped vibrating gyroscope 600 obtained by modifying a part of the first embodiment. FIG. 10 is a cross-sectional view taken along the line CC of FIG.

  In the ring-shaped vibrating gyroscope 600 of this embodiment, a fixed end 60 is formed around the ring-shaped vibrating body 11 via a groove or leg portion 17 as compared with the second embodiment. Further, on the leg portion 17 and the fixed end 60, the extraction electrode 14 and the electrode pad 18 starting from the four drive electrodes 13a,..., 13a and the two monitor electrodes 13f, 13f are formed. Further, since the lead electrode 14 on the leg portion 17 is formed, the lead electrode 14 and the electrode pad 18 on the leg portion 15 and the fixed end 19 are removed. Furthermore, in this embodiment, eight leg parts 15 are removed among the 16 leg parts 15 which the ring-shaped vibrating gyroscope 500 of 2nd Embodiment has. The ring-shaped vibrating gyroscope 600 of the present embodiment has the same configuration as that of the second embodiment except for the points described above. The manufacturing method is the same as that of the first embodiment except for a part. Furthermore, the vibration mode of the primary vibration and the vibration mode of the secondary vibration of the present embodiment are the same vibration modes as those of the second embodiment. Therefore, the description which overlaps with 1st Embodiment may be abbreviate | omitted. In the present embodiment, in order to make the drawing easy to see, the AC power source connected to the four drive electrodes 13a,..., 13a is not shown.

  Formation of the leg portion 17 of the present embodiment eliminates the need for complicated wiring on the ring-shaped vibrating body 11. Therefore, the risk of a short circuit between the extraction electrodes due to defects in the manufacturing process is greatly reduced. As shown in FIG. 9, since the extraction electrode 14 is joined to the central portion of the width of each electrode, the electric signal is not biased. Moreover, since the space | interval of each leg part 15 and 17 spreads, the improvement of the throughput by the etching rate improving on a manufacturing process and the improvement of the yield of an etching process can be anticipated. On the other hand, the formation of the fixed end 60 increases the size of the vibration gyro as compared with that of the first embodiment.

  In this embodiment as well, two drive electrodes 13a and 13a arranged at an angle of (360/3) ° in the circumferential direction, that is, 120 ° apart, and (180/3) ° from each of these drive electrodes. That is, two drive electrodes 13a and 13a arranged at an angle of 60 ° are arranged. Therefore, the ring-shaped vibrating gyroscope 600 of the present embodiment has an amplitude larger than that of the ring-shaped vibrating gyroscope including a group of driving electrodes arranged only at an angle of (360/3) °, that is, 120 ° in the circumferential direction. Increase or power saving is achieved.

  By the way, although each above-mentioned embodiment was demonstrated with the vibration gyro using an annular | circular shaped vibrating body, a polygonal-shaped vibrating body may be sufficient instead of an annular shape. For example, even with a regular polygonal vibrator such as a regular hexagon, a regular octagon, a regular dodecagon, and a regular icosahedron, substantially the same effect as the effect of the present invention is exhibited. Further, a vibrating body such as a dodecagonal vibrating body 111 of the ring-shaped vibrating gyroscope 700 shown in FIG. 13 may be used. In the front view of the vibrating body, for example, a polygon having a point-symmetrical shape or an n-fold symmetrical shape (n is an arbitrary natural number) with an arbitrary point such as the reference point described above as the center of symmetry is defined as an outer peripheral edge or an inner peripheral edge. If such a ring-shaped vibrating body is employed, it is preferable from the viewpoint of stability during vibration of the vibrating body. The “annular shape” includes an elliptical shape. In FIG. 13, unlike FIG. 1 and the like, the leg portion and the support column are not shown in order to make the drawing easier to see.

  In the first embodiment described above and the modifications (1) to (3) thereof, the monitor electrode 13f is disposed in the same position or region. However, the present invention is not limited to this. That is, the monitor electrode 13f is a case where N is a natural number greater than or equal to 2 or 3, and one of the drive electrodes 13a is a reference drive electrode, and M = 0, 1,. (Hereinafter, the same in this paragraph) is necessarily arranged at an angle of [(360 / N) × {M + (1/2)}] ° in the circumferential direction from the reference drive electrode 13a. There is no need. For example, in the case of the vibration mode of cosNθ, where L = 0, 1,..., 2N−1 (hereinafter the same in this paragraph), each monitor electrode 13f is connected to the reference drive electrode by Arrangement is made so as to avoid an arrangement with an angle other than (180 / N) × {L + (1/2)} ° apart in the circumferential direction, or an arrangement that is axisymmetric with respect to the position of the angle. Thus, the effect of the first embodiment or its modification is substantially achieved. In particular, in the limited planar region of the ring-shaped vibrating body 11 that is miniaturized, the arrangement of the monitor electrode 13f as shown in the first embodiment is different from the arrangement of other electrode groups and / or the extraction electrode. Will be easier to arrange. Specifically, the monitor electrode 13f is a case where N is a natural number greater than or equal to 2 or 3, and one of the drive electrodes 13a is a reference drive electrode, and M = 0, 1,. In the case of N-1 (hereinafter the same in this paragraph), it is arranged at an angle of [(360 / N) × {M + (1/2)}] ° in the circumferential direction from the reference drive electrode 13a. This is a preferable embodiment.

  A specific example of the above is the ring-shaped vibrating gyroscope 800 shown in FIG. 14A. The monitor electrodes 213f and 213f of the ring-shaped vibrating gyroscope 800 are obtained when N is a natural number of 2 or more, or 3 or more, and one of the drive electrodes 13a is a reference drive electrode, and M = 0, 1,. .., N-1 (hereinafter the same in this paragraph), it is not necessarily [(360 / N) × {M + (1/2)}] degrees away from the reference drive electrode 13a in the circumferential direction Is not arranged at an angle. However, even with the arrangement of the monitor electrodes 213f and 213f shown in FIG. 14A, the same effect as in the first embodiment can be obtained.

  Another example is a ring-shaped vibrating gyroscope 820 shown in FIG. 14B. A part of the monitor electrodes 413f and 413f of the ring-shaped vibrating gyroscope 880 is disposed on a region from the inner peripheral edge of the ring-shaped vibrating body 11 to the center line. On the other hand, the electrode areas of the second detection electrodes 13d and 13e are reduced. However, even with the arrangement of the monitor electrodes 413f and 413f shown in FIG. 14B, the S (signal) and N (noise) ratio (so-called S / N ratio) deteriorates as the sensitivity of the detection electrode decreases. Thus, the same effects as those of the first embodiment are achieved. Similarly, even if one or all of the monitor electrodes 413f and 413f are arranged on the region from the outer peripheral edge of the ring-shaped vibrating body 11 to the center line, the same effect as that of the first embodiment is obtained. Is done.

  Another example is a ring-shaped vibrating gyroscope 840 shown in FIG. 14C. This example is a modification of the ring-shaped vibrating gyroscope 700 shown in FIG. The three monitor electrodes 513f, 513f, and 513f of the ring-shaped vibrating gyroscope 840 are disposed on a region from the outer peripheral edge of the ring-shaped vibrating body 11 to the center line. Further, in particular, two of the three monitor electrodes 513f, 513f, and 513f are arranged at an angle apart from each other by an equal angle clockwise and counterclockwise around the one drive electrode 13a. However, even with the arrangement of the monitor electrodes 513f, 513f, and 513f shown in FIG. 14C, the same effects as those of the first embodiment can be obtained.

  Another example is a ring-shaped vibrating gyroscope 860 shown in FIG. 14D. This example is also a modification of the ring-shaped vibrating gyroscope 700 shown in FIG. The four monitor electrodes 613f,..., 613f of the ring-shaped vibrating gyroscope 860 are disposed on a region from the outer peripheral edge of the ring-shaped vibrating body 11 to the center line. Further, in particular, two of the four monitor electrodes 613f,..., 613f are arranged at an angle separated from each other by an equal angle clockwise and counterclockwise around the one drive electrode 13a. Yes. Similarly, the other two are arranged at an angle separated from each other by an equal angle clockwise and counterclockwise around the single drive electrode 13a. Moreover, two of the four monitor electrodes 613f,..., 613f are arranged at point-symmetric positions. However, even with the arrangement of the monitor electrodes 613f,..., 613f shown in FIG. In the present embodiment, the arrangement of the four monitor electrodes 613h,..., 613h described above makes it possible to keep the magnitude of the primary vibration constant without being affected by the newly generated secondary vibration. Become. In addition, the arrangement at the point-symmetrical position reduces the detection sensitivity of one monitor electrode even if patterning misalignment occurs due to misalignment of the etching mask in the manufacturing process of the vibrating gyroscope, for example. Can be compensated by an increase in detection sensitivity of the other monitor electrode. Therefore, the arrangement of the monitor electrodes improves the detection accuracy of the amplitude and resonance frequency of the primary vibration of the ring-shaped vibrating body 11 which is the original role of the monitor electrodes 613h,.

  Needless to say, the technical idea of the arrangement of the monitor electrodes 13f, 413f, 513f, and 613f described above can be applied to the second embodiment described above.

  As shown in the above examples, the ring-shaped vibrating gyroscope of the present invention is excited by the primary vibration of the out-of-plane vibration mode, so that the arrangement of the monitor electrodes on the plane of the ring-shaped vibrating body 11 is increased. If it is on the area | region from the inner periphery to an outer periphery, a high freedom degree will be given. However, for example, in the case of the vibration mode of cosNθ, where L = 0, 1,..., 2N−1 (hereinafter the same in this paragraph), each monitor electrode 13f is a reference drive electrode. Is arranged so as to avoid an arrangement at an angle of (180 / N) × {L + (1/2)} ° in the circumferential direction, or an arrangement that is line-symmetric with respect to the position of the angle. The reason for the former is that the distortion of the ring-shaped vibrator 11 becomes zero (0) when arranged at that position. Moreover, the latter reason is because the distortion directions are opposite to each other, so that the distortions are offset. In particular, in the limited planar region of the ring-shaped vibrating body 11 that is miniaturized, the arrangement of the monitor electrode 13f as shown in the first embodiment is different from the arrangement of other electrode groups and / or the extraction electrode. Will be easier to arrange. Specifically, the monitor electrode 13f is a case where N is a natural number greater than or equal to 2 or 3, and one of the drive electrodes 13a is a reference drive electrode, and M = 0, 1,. In the case of N-1 (hereinafter the same in this paragraph), it is arranged at an angle of [(360 / N) × {M + (1/2)}] ° in the circumferential direction from the reference drive electrode 13a. This is a preferable embodiment.

  On the other hand, it is also a preferable aspect that a part of the detection electrodes in the above-described embodiments is replaced with a suppression electrode that suppresses secondary vibration based on a voltage signal from each detection electrode. The specific embodiment will be described below.

<Third Embodiment>
FIG. 15 is a front view of a structure that plays a central role in a ring-shaped vibrating gyroscope 900 that measures biaxial angular velocities in the present embodiment. The ring-shaped vibrating gyroscope 900 of the present embodiment has the same configuration as the ring-shaped vibrating gyroscope 100 of the first embodiment except for the action of a part of the upper metal film 50 in the first embodiment. The manufacturing method is the same as that of the first embodiment except for a part. Furthermore, the vibration mode of the primary vibration and the vibration mode of the secondary vibration in the present embodiment are the same vibration modes as those in the first embodiment. Therefore, the description which overlaps with 1st Embodiment may be abbreviate | omitted.

  As shown in FIG. 15, the ring-shaped vibrating gyroscope 900 of this embodiment includes a plurality of suppression electrodes 13j. These suppression electrodes 13j are arranged in a region from the outer peripheral edge of the ring-shaped vibrating body 900 to the vicinity of the outer peripheral edge and a region from the inner peripheral edge of the ring-shaped vibrating body 900 to the vicinity of the inner peripheral edge. ing.

  In the present embodiment, the area where each electrode is arranged is classified into two. One is a first detection electrode disposed in a region from the outer periphery of the upper surface of the ring-shaped vibrating body 11 to the vicinity of the outer periphery and / or a region from the inner periphery to the vicinity of the inner periphery. 13b, the suppression electrode 13j, and the second detection electrodes 13d and 13e. This is the second electrode arrangement region. The other is an area on the upper surface of the ring-shaped vibrating body 11 where the drive electrodes 13a, 13a, 13a arranged so as not to be in electrical contact with the second electrode arrangement area are formed. This is defined as a first electrode arrangement region. The arrangement of the first detection electrode 13b and the suppression electrode 13j on the upper surface of the ring-shaped vibrating body is such that one is arranged on the inner circumferential edge side and the other is arranged on the outer circumferential edge side. The arrangement of is reversed every time the angle is advanced to 0 °, 60 °, 120 °. More specifically, the first detection electrode 13b, the suppression electrode 13j, and the second detection electrodes 13d and 13e are arranged so as not to be electrically connected to any of the three drive electrodes 13a, 13a, and 13a. .

  Next, the operation of each electrode provided in the ring-shaped vibrating gyroscope 900 will be described. As described above, in this embodiment, the primary vibration of the out-of-plane cos 2θ vibration mode is excited. Since the fixed potential electrode 16 is grounded, the lower electrode film 30 formed continuously with the fixed potential electrode 16 is uniformly at 0V.

First, an AC voltage of 1 V _P-0 is applied to the three drive electrodes 13 a, 13 a, and 13 a. However, in FIG. 15, the phase of the voltage applied to the driving electrode 13a in the 3 o'clock direction of the timepiece is opposite to the phase of the voltage applied to the other two driving electrodes 13a and 13a. As a result, the piezoelectric film 40 expands and contracts to excite primary vibration. Here, in the present embodiment, the upper metal film 50 is formed so as to include the center line of the ring-shaped vibrating body 11 in a front view. This is to prevent the vibration similar to the secondary vibration that is the in-plane vibration mode from being excited by the AC voltage applied to the three drive electrodes 13a, 13a, and 13a. However, if the resonance frequencies of the ring-shaped vibrating body 11 of the primary vibration and the secondary vibration are different, the drive electrodes 13a may be arranged so as not to include the center line.

  Next, the monitor electrode 13f shown in FIG. 15 detects the amplitude and resonance frequency of the primary vibration described above, and transmits a signal to a known feedback control circuit (not shown). The feedback control circuit of the present embodiment uses the signal from the monitor electrode 13f to control the frequency of the AC voltage applied to the drive electrodes 13a, 13a, and 13a so as to match the natural frequency of the ring-shaped vibrating body 11. At the same time, the amplitude of the ring-shaped vibrating body 11 is controlled to be a certain value. As a result, the ring-shaped vibrating body 11 maintains a constant vibration.

  Here, a case where an angular velocity is applied around the X-axis after the above-described primary vibration is excited will be described. In this case, as in the first embodiment, a secondary vibration in the vibration mode of in-plane cos 3θ is generated.

  This secondary vibration is detected by six detection electrodes (first detection electrodes) 13b, ..., 13b. In the present embodiment, as shown in FIG. 15, each detection electrode 13b is arranged corresponding to the vibration axis of the in-plane secondary vibration. In the present embodiment, each of the detection electrodes 13b described above is arranged on the outer side of the center line on the upper surface of the ring-shaped vibrating body 11 and so as to most easily detect the secondary vibration to be detected, that is, the in-plane vibration mode. Arranged inside.

  In this embodiment, due to the arrangement of the detection electrodes 13b, the electrical signals of the detection electrodes 13b generated by the in-plane secondary vibration excited by the angular velocity are the same in all the detection electrodes 13b. Therefore, the electric signal from each detection electrode 13b and the difference signal of the fixed electrode terminal 16 are amplified by a known amplifier circuit.

  Here, the ring-shaped vibrating gyroscope 900 of the present embodiment cancels voltage signals related to secondary vibration detected by the first detection electrodes 13b, in other words, sets the values of the voltage signals to zero. In addition, a first secondary vibration suppression feedback control circuit 62 for indicating or controlling the voltage applied to the suppression electrode 13j is provided. As a result output as a vibrating gyroscope, a voltage value applied to the suppression electrode 13j or a value corresponding to the voltage is used.

  Next, a case where an angular velocity is applied around the Y axis after the above-described primary vibration is excited will be described. In this case as well, the secondary vibration in the vibration mode of in-plane cos 3θ is generated as in the first embodiment.

  This secondary vibration is detected by six detection electrodes (second detection electrodes) 13d,..., 13d and another six detection electrodes (second detection electrodes) 13e,. In the present embodiment, as shown in FIG. 15, the detection electrodes 13d and 13e are arranged corresponding to the vibration axes of the in-plane secondary vibration. In the present embodiment, each of the detection electrodes 13d and 13e described above also has a center line on the upper surface of the ring-shaped vibrating body 11 so that the secondary vibration to be detected, that is, the in-plane vibration mode, can be detected most easily. The outer side and the inner side are arranged.

  In the present embodiment, a suppression electrode 13j for suppressing secondary vibration is provided based on the voltage signal from the first detection electrode 13b, and secondary vibration is generated by the first secondary vibration suppression feedback control circuit 62 therein. An electrical signal that suppresses the voltage is applied. Thereby, the ring-shaped vibrating gyroscope 900 can exhibit the performance as a vibrating gyroscope with almost no secondary vibration in the mode as shown in FIG. 11B of the ring-shaped vibrating body 11. In addition, the ring-shaped vibration gyroscope 900 of this embodiment is very excellent in noise performance compared with the vibration gyroscope in which the suppression electrode 13j and the first secondary vibration suppression feedback control circuit are not provided. Specifically, the ring-shaped vibrating gyroscope 900 of this embodiment is compared with an example of the vibrating gyroscope described in PCT / JP2009 / 052959 previously proposed by the applicant of the present application (vibrating gyroscope of the first embodiment). As a result, the magnitude of the noise in the low-frequency region in detecting the angular velocity around the X axis becomes half or less. Therefore, the S / N ratio is dramatically increased without sacrificing responsiveness in detection of the angular velocity around the X axis. A known feedback control circuit can be applied to the first secondary vibration suppression feedback control circuit described above.

  In the present embodiment, due to the arrangement of the second detection electrodes 13d and 13e, the electrical signal of the second detection electrode 13d generated by the in-plane secondary vibration excited by the angular velocity and the second detection electrode 13e. The sign of the electrical signal is opposite to that of the electrical signal. Accordingly, it is possible to calculate a difference signal between the electric signal from the second detection electrode 13d and the electric signal from the detection electrode 13e by an arithmetic circuit which is a known difference circuit. In this case, the detection signal of the angular velocity around the Y axis has a detection capability that is approximately twice that of the case where only one of the detection electrodes is used.

  In this embodiment as well, two drive electrodes 13a and 13a arranged at an angle of (360/2) ° in the circumferential direction, that is, 180 ° apart, and (180/2) ° from each of these drive electrodes. That is, one drive electrode 13a disposed at an angle of 90 ° is disposed. Therefore, the ring-shaped vibrating gyroscope 900 of the present embodiment has an amplitude larger than that of the ring-shaped vibrating gyroscope including a group of drive electrodes arranged only at an angle of (360/2) °, that is, 180 ° in the circumferential direction. Increase or power saving is achieved.

  By the way, in this embodiment, for the sake of convenience, the names of the first detection electrode and the second detection electrode are given to the detection electrodes for detecting each of the two axes for which the angular velocity is to be detected. As the name of the detection electrode, any one non-overlapping name of the first detection electrode and the second detection electrode may be given.

  By the way, in each above-mentioned embodiment, although each electrode was formed by patterning an upper metal film, this invention is not limited to this. For example, even if each electrode is formed by patterning only the lower metal film or both the upper metal film and the lower metal film, the same effect as that of the present invention can be obtained. However, considering the ease of manufacturing, it is a preferable aspect that only the upper metal film is patterned as in the above-described embodiments.

  Needless to say, the technical idea of the third embodiment in which the suppression electrode 13j is arranged can also be applied to other embodiments.

  Furthermore, in each of the embodiments described above, a ring-shaped vibrating gyroscope using silicon as a base material is employed, but the present invention is not limited to this. For example, the base material of the vibration gyro may be germanium or silicon germanium. Among the above, in particular, adoption of silicon or silicon germanium can greatly improve the processing accuracy of the entire gyro including the vibrating body because a known anisotropic dry etching technique can be applied. As described above, modifications that exist within the scope of the present invention including other combinations of the embodiments are also included in the scope of the claims.

  The present invention can be applied as a part of various devices as a vibrating gyroscope.

DESCRIPTION OF SYMBOLS 10 Silicon substrate 11 Ring-shaped vibrating body 12 AC power supply 13a Drive electrode 13b, 13c 1st detection electrode 13d, 13e 2nd detection electrode 13f, 213f, 413f, 513f, 613f Monitor electrode 14 Lead electrode 15, 17 Leg part 16 Fixed potential Electrode (ground electrode)
18 Electrode pad 19 Support 20 Silicon oxide film 30 Lower metal film 40 Piezoelectric film 50 Upper metal film 60 Fixed end 100, 200, 300, 400, 500, 600, 700, 800, 820, 840, 860, 900 Ring-shaped vibration gyro

Claims (11)

A ring-shaped vibrating body with a uniform plane;
A leg portion that flexibly supports the ring-shaped vibrating body;
A plurality of electrodes placed on or above the plane of the ring-shaped vibrator and formed by at least one of an upper metal film and a lower metal film sandwiching the piezoelectric film in the thickness direction;
The plurality of electrodes are the following (1) and (2), that is,
(1) When N is a natural number equal to or greater than 2, the primary vibration of the ring-shaped vibrating body is excited in the vibration mode of cosNθ, and the drive is arranged at an angle separated by (360 / N) ° in the circumferential direction. A group of drive electrodes including electrodes and at least one drive electrode disposed at any angle (180 / N) ° from each of the drive electrodes;
(2) When one of the drive electrodes is a reference drive electrode and S = 0, 1,..., N (hereinafter, the same), an angular velocity is applied to the ring-shaped vibrating body. The secondary vibration in the vibration mode of cos (N + 1) θ is detected, and an angle [{360 / (N + 1)} × S] ° away from the reference drive electrode, and {{360 / ( N + 1)} × {S + (1/2)}] ° apart from a group of detection electrodes comprising electrodes arranged at at least one of the angles
Each of the drive electrodes is arranged in a first electrode arrangement region in the plane of the ring-shaped vibrating body,
Each of the detection electrodes includes any one of a region from the outer peripheral edge of the ring-shaped vibrating body to the vicinity of the outer peripheral edge and a region from the inner peripheral edge of the ring-shaped vibrating body to the vicinity of the inner peripheral edge. The vibration gyro is arranged in the second electrode arrangement region in the plane including both or both regions, and is not electrically connected to any of the drive electrodes. A ring-shaped vibrating body with a uniform plane;
A leg portion that flexibly supports the ring-shaped vibrating body;
A plurality of electrodes placed on or above the plane of the ring-shaped vibrator and formed by at least one of an upper metal film and a lower metal film sandwiching the piezoelectric film in the thickness direction;
The plurality of electrodes are the following (1) and (2), that is,
(1) When N is a natural number equal to or greater than 2, the primary vibration of the ring-shaped vibrating body is excited in the vibration mode of cosNθ, and the drive is arranged at an angle separated by (360 / N) ° in the circumferential direction. A group of drive electrodes including electrodes and at least one drive electrode disposed at any angle (180 / N) ° from each of the drive electrodes;
(2) When one of the drive electrodes is a reference drive electrode and S = 0, 1,..., N (hereinafter, the same), an angular velocity is applied to the ring-shaped vibrating body. Detecting the secondary vibration in the vibration mode of cos (N + 1) θ, and an angle away from the reference drive electrode by [{360 / (N + 1)} × {S + (1/4)}] ° and the reference drive A group of detection electrodes comprising electrodes arranged at least at any angle of [{360 / (N + 1)} × {S + (3/4)}] ° away from the electrodes;
Each of the drive electrodes is arranged in a first electrode arrangement region in the plane of the ring-shaped vibrating body,
Each of the detection electrodes includes any one of a region from the outer peripheral edge of the ring-shaped vibrating body to the vicinity of the outer peripheral edge and a region from the inner peripheral edge of the ring-shaped vibrating body to the vicinity of the inner peripheral edge. The vibration gyro is arranged in the second electrode arrangement region in the plane including both or both regions, and is not electrically connected to any of the drive electrodes. A ring-shaped vibrating body with a uniform plane;
A leg portion that flexibly supports the ring-shaped vibrating body;
A plurality of electrodes placed on or above the plane of the ring-shaped vibrator and formed by at least one of an upper metal film and a lower metal film sandwiching the piezoelectric film in the thickness direction;
The plurality of electrodes are the following (1) and (2), that is,
(1) When N is a natural number greater than or equal to 3, the primary vibration of the ring-shaped vibrating body is excited in the vibration mode of cosNθ, and the drive is arranged at an angle separated by (360 / N) ° in the circumferential direction. A group of drive electrodes including electrodes and at least one drive electrode disposed at any angle (180 / N) ° from each of the drive electrodes;
(2) When one of the drive electrodes is a reference drive electrode and S = 0, 1,..., N-2 (hereinafter the same), an angular velocity is given to the ring-shaped vibrating body. A secondary vibration in the vibration mode of cos (N−1) θ generated in the electrode, and an electrode disposed at an angle of [{360 / (N−1)} × S] ° from the reference drive electrode; , A group of detection electrodes comprising electrodes arranged at least at any angle of [{360 / (N−1)} × {S + (1/2)}] ° away from the reference drive electrode And
Each of the drive electrodes is arranged in a first electrode arrangement region in the plane of the ring-shaped vibrating body,
Each of the detection electrodes includes any one of a region from the outer peripheral edge of the ring-shaped vibrating body to the vicinity of the outer peripheral edge and a region from the inner peripheral edge of the ring-shaped vibrating body to the vicinity of the inner peripheral edge. The vibration gyro is arranged in the second electrode arrangement region in the plane including both or both regions, and is not electrically connected to any of the drive electrodes. A ring-shaped vibrating body with a uniform plane;
A leg portion that flexibly supports the ring-shaped vibrating body;
A plurality of electrodes placed on or above the plane of the ring-shaped vibrator and formed by at least one of an upper metal film and a lower metal film sandwiching the piezoelectric film in the thickness direction;
The plurality of electrodes are the following (1) and (2), that is,
(1) When N is a natural number greater than or equal to 3, the primary vibration of the ring-shaped vibrating body is excited in the vibration mode of cosNθ, and the drive is arranged at an angle separated by (360 / N) ° in the circumferential direction. A group of drive electrodes including electrodes and at least one drive electrode disposed at any angle (180 / N) ° from each of the drive electrodes;
(2) When one of the drive electrodes is a reference drive electrode and S = 0, 1,..., N-2 (hereinafter the same), an angular velocity is given to the ring-shaped vibrating body. The secondary vibration of the vibration mode of cos (N−1) θ generated at the same time is detected, and [{360 / (N−1)} × {S + (1/4)}] ° away from the reference drive electrode A group of electrodes including electrodes arranged at at least one of an angle and an angle [{360 / (N−1)} × {S + (3/4)}] ° away from the reference drive electrode. A detection electrode,
Each of the drive electrodes is arranged in a first electrode arrangement region in the plane of the ring-shaped vibrating body,
Each of the detection electrodes includes any one of a region from the outer peripheral edge of the ring-shaped vibrating body to the vicinity of the outer peripheral edge and a region from the inner peripheral edge of the ring-shaped vibrating body to the vicinity of the inner peripheral edge. The vibration gyro is arranged in the second electrode arrangement region in the plane including both or both regions, and is not electrically connected to any of the drive electrodes. When the detection electrode is a first detection electrode, the plurality of electrodes are the following (3):
(3) A secondary vibration of a vibration axis having an angle of {90 / (N + 1)} ° with respect to the secondary vibration is detected, and [{360 / (N + 1)} × {S + ( 1/4)}] [deg.] Away from the reference drive electrode and [{360 / (N + 1)} × {S + (3/4)}] [deg.] Away from the reference drive electrode. And a group of second detection electrodes comprising the formed electrodes,
The vibrating gyroscope according to claim 1, wherein each of the second detection electrodes is arranged on the second electrode arrangement region. When the detection electrode is a first detection electrode, the plurality of electrodes are the following (3):
(3) The secondary vibration of the vibration axis at an angle of {90 / (N-1)} ° with respect to the secondary vibration is detected, and {{360 / (N-1)} from the reference drive electrode × {S + (1/4)}] ° apart from at least an angle {{360 / (N−1)} × {S + (3/4)}] ° away from the reference drive electrode A group of second detection electrodes comprising electrodes arranged at any angle;
The vibrating gyroscope according to claim 3, wherein each of the second detection electrodes is arranged on the second electrode arrangement region. The plurality of electrodes are
(4) When M = 0, 1,..., 2N−1 (hereinafter the same), (180 / N) × {M + (1/2)} ° in the circumferential direction from the reference drive electrode. The vibration gyro according to any one of claims 1 to 6, further comprising a group of monitor electrodes arranged at an angle other than the separated angle. The plurality of electrodes are
(4) When one of the drive electrodes is a reference drive electrode and M = 0, 1,..., N−1 (hereinafter the same), [( The vibration gyro according to any one of claims 1 to 6, further comprising a group of monitor electrodes arranged at an angle apart from 360 / N) × {M + (1/2)}] °. The vibrating gyroscope according to any one of claims 1 to 6, wherein the first electrode arrangement region includes a center line that connects a center of a width from the outer peripheral edge to the inner peripheral edge. The ring-shaped vibrator is formed of a silicon substrate;
The vibration gyro according to any one of claims 1 to 6, wherein substantially only the upper metal film, the piezoelectric film, and the lower metal film are observed in a front view. The ring-shaped vibrator is formed of a silicon substrate;
The vibrating gyroscope according to any one of claims 1 to 6, wherein substantially only the upper metal film and the lower metal film are observed in a front view.

Images