Vibratory gyro element and gyroscope

Abstract

In this vibration type gyro element (100), electrodes (40) include primary drive electrodes (PD), primary detection electrodes (PPO), secondary detection electrodes (SPO), and secondary drive electrodes (SD). Electrical connections are configured for the primary drive electrodes, the primary detection electrodes, the secondary detection electrodes, and the secondary drive electrodes such that the electric potential difference with regard to the surrounding electrodes is maintained before and after swapping, with the locations and directions of current of the electrodes that are to be swapped being treated as a reference.

Description

Technical Field

[0001] The present invention relates to a vibrating gyro element and a gyroscope, and more particularly to a vibrating gyro element including a vibrator and electrodes, and a gyroscope including the same.

Background Art

[0002] Conventionally, a gyroscope including a vibrating gyro element including a vibrator and electrodes has been known. Such a gyroscope is disclosed, for example, in Japanese Patent Application Laid-Open No. 2009-115559.

[0003] Japanese Patent Application Laid-Open No. 2009-115559 discloses a gyroscope including a vibrating gyro element. The vibrating gyro element includes a ring-shaped element portion (vibrator) and electrodes. A plurality of electrodes are arranged at predetermined angular intervals along a direction around the center of the element portion. The plurality of electrodes include a primary drive electrode that generates a primary vibration in the element portion, a primary detection electrode that detects the primary vibration, a secondary detection electrode that detects a secondary vibration of the element portion, and a secondary drive electrode that cancels the secondary vibration. In the gyroscope, the angular velocity is calculated based on an AC voltage applied to the secondary drive electrode to cancel the secondary vibration.

[0004] In addition, in a conventional gyroscope as described in Japanese Patent Application Laid-Open No. 2009-115559, a bias component is included in the angular velocity detected by the gyroscope. The bias component, also called zero-point output or offset, is caused by an angular deviation between a plurality of electrodes provided in the vibrating gyro element, or in the case of a vibrating gyro element driven electromagnetically, by non-uniformity of the applied magnetic field. Therefore, in the gyroscope described in Japanese Patent Application Laid-Open No. 2009-115559, the primary drive electrode and the primary detection electrode, and the secondary drive electrode and the secondary detection electrode are interchanged, and the output signals of the gyroscope before and after the interchange are differentiated to cancel the bias component.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-115559 [Summary of the Invention] [Problems to be Solved by the Invention]

[0006] However, in the gyroscope as described in Japanese Patent Application Laid-Open No. 2009-115559, as follows, even if the output signals of the gyroscope before and after the replacement are differentiated, there may be a bias component that cannot be canceled remaining. Specifically, in the gyroscope as described in Japanese Patent Application Laid-Open No. 2009-115559, there is a potential difference between an electrode having a certain function and the surrounding electrodes. Further, since an alternating current flows through the electrodes, a displacement current corresponding to the potential difference is generated between an electrode having a certain function and the surrounding electrodes. In this case, a magnetic field is generated by the displacement current, and the influence (bias component) due to the magnetic field derived from the displacement current is superimposed on the output signal. Thus, when the influence (bias component) due to the magnetic field derived from the displacement current is superimposed on the output signal, since the potential difference between an electrode having a certain function and the surrounding electrodes is different before and after the replacement, even if the output signals before and after the replacement are differentiated, the influence (bias component) due to the magnetic field derived from the displacement current remains without being canceled. For this reason, in a configuration in which replacement is performed, it is desired to sufficiently cancel the influence due to the magnetic field derived from the displacement current.

[0007] This invention has been made to solve the above-described problems, and one object of this invention is to provide a vibration type gyro element and a gyroscope capable of sufficiently canceling the influence due to the magnetic field derived from the displacement current in a configuration in which replacement is performed. [Means for Solving the Problems]

[0008] In order to achieve the above object, a vibrating gyro element according to a first aspect of the present invention is a vibrating gyro element driven by electromagnetic drive, including a fixed portion, a vibrator, a support portion that connects the vibrator and the fixed portion and supports the vibrator so as to be vibratable, a plurality of electrodes arranged in a row at intervals in the circumferential direction of the vibrator on the surface of the vibrator, and a magnetic field applying portion that applies a magnetic field to the electrodes. The vibrator has a vibration mode of cosNθ (N is a natural number of 2 or more). The electrodes include a primary drive electrode that excites a primary vibration of the vibrator, a primary detection electrode that detects the primary vibration, a secondary detection electrode that detects a secondary vibration of the vibrator, and a secondary drive electrode that drives the vibrator so as to cancel the secondary vibration. The primary drive electrode is configured to be interchangeable with either the secondary drive electrode or the secondary detection electrode, and the primary detection electrode is configured to be interchangeable with the other of the secondary detection electrode or the secondary drive electrode. The primary drive electrode, the primary detection electrode, the secondary detection electrode, and the secondary drive electrode are electrically connected so that the potential difference from the surrounding electrodes is maintained based on the position of the electrode to be interchanged and the direction of the current before and after the interchange.

[0009] In the vibrating gyro element according to the first aspect of the present invention, as described above, the primary drive electrode, the primary detection electrode, the secondary detection electrode, and the secondary drive electrode are electrically connected so that the potential difference from the surrounding electrodes is maintained based on the position of the electrode to be interchanged and the direction of the current before and after the interchange. As a result, the potential difference between the electrode having a certain function and the surrounding electrodes can be made equal before and after the interchange, so that the influence of the magnetic field due to the displacement current can be equally superimposed on the output signals before and after the interchange. As a result, for example, when the output signals before and after the interchange are differentiated, the influence (bias component) of the magnetic field due to the displacement current can be sufficiently canceled (made zero or near zero). That is, in the configuration where the interchange is performed, the influence (bias component) of the magnetic field due to the displacement current can be sufficiently canceled. Further, since the influence (bias component) of the magnetic field due to the displacement current can be sufficiently canceled, the detection accuracy of the angular velocity can be improved in a gyroscope including the vibrating gyro element.

[0010] In the vibrating gyro element according to the first aspect, preferably, before and after the replacement, the primary drive electrode, the primary detection electrode, the secondary detection electrode, and the secondary drive electrode are based on the position and current direction of the electrodes to be replaced, and the positions and functions of the surrounding electrodes are the same, the positions and current directions of the surrounding electrodes are the same, and the electrical connection order for each position and function of the surrounding electrodes is the same. Electrical connections are set so as to satisfy the conditions including these. With this configuration, the potential difference between the electrode having a certain function and the surrounding electrodes can be easily made equal before and after replacement, so that the influence (bias component) due to the magnetic field from the displacement current can be easily and sufficiently canceled.

[0011] In this case, preferably, the positions of the electrodes on the surface of the vibrator among the primary drive electrode, the primary detection electrode, the secondary detection electrode, and the secondary drive electrode, the current directions of the electrodes, and the electrical connection order for each function of the electrodes pass through the center of the vibrator and are relative to the virtual symmetry axis extending in the radial direction of the vibrator. The positions on the surface of the vibrator, the current directions, and the electrical connection order of the electrodes for each function of the electrodes to be set as the replacement partners are set to be line-symmetric. With this configuration, without changing the current direction and the electrical connection order of the electrodes (that is, without changing the current path for each function) before and after replacement, a configuration can be realized in which the potential difference between the electrode having a certain function and the surrounding electrodes is made equal. As a result, different from the case of realizing a configuration in which the potential difference between the electrode having a certain function and the surrounding electrodes is made equal by changing at least one of the current direction and the electrical connection order of the electrodes for each function (that is, by changing the current path for each function) before and after replacement, there is no need to provide a structure such as a switch for changing the current path for each function. Thereby, a structure in which the potential difference between the electrode having a certain function and the surrounding electrodes is made equal before and after replacement can be realized with a simple structure.

[0012] In the configuration where the virtual symmetry axis is provided, preferably, a plurality of electrode rows are arranged on the surface of the vibrator, spaced apart from each other in the circumferential direction of the vibrator, and extending in parallel. With this configuration, a plurality of electrode rows can be easily arranged on the surface of the vibrator.

[0013] In this case, preferably, the primary drive electrodes are alternately arranged in the same row as either the secondary detection electrodes or the secondary drive electrodes, and the primary detection electrodes are alternately arranged in the same row as the other of the secondary detection electrodes or the secondary drive electrodes. With this configuration, a set of the primary drive electrodes that are interchanged with either the secondary detection electrodes or the secondary drive electrodes can be grouped in the same row, and a set of the primary detection electrodes that are interchanged with the other of the secondary detection electrodes or the secondary drive electrodes can be grouped in the same row. Therefore, the electrodes of the primary drive electrodes, the primary detection electrodes, the secondary detection electrodes, and the secondary drive electrodes can be arranged in a well-balanced manner. In addition, since the electrodes of the primary drive electrodes, the primary detection electrodes, the secondary detection electrodes, and the secondary drive electrodes are alternately arranged, a virtual symmetry axis can be easily provided.

[0014] In the vibration type gyro element according to the first aspect, preferably, the primary drive electrodes, the primary detection electrodes, the secondary detection electrodes, and the secondary drive electrodes are each electrically connected in the clockwise order or the counterclockwise order for each function. With this configuration, the structure of the wiring for electrically connecting between the electrodes can be simplified in each of the primary drive electrodes, the primary detection electrodes, the secondary detection electrodes, and the secondary drive electrodes.

[0015] To achieve the above object, a gyroscope according to a second aspect of the present invention includes a vibration type gyro element driven by electromagnetic force, and an arithmetic unit that calculates an angular velocity based on an output signal from the vibration type gyro element. The vibration type gyro element includes a fixed part, a vibrator, a support part that connects the vibrator and the fixed part and supports the vibrator so as to be vibratable, a plurality of electrodes arranged in a row at intervals in the circumferential direction of the vibrator on the surface of the vibrator, and a magnetic field applying part that applies a magnetic field to the electrodes. The vibrator has a vibration mode of cosNθ (N is a natural number of 2 or more). The electrodes include a primary drive electrode that excites a primary vibration of the vibrator, a primary detection electrode that detects the primary vibration, a secondary detection electrode that detects a secondary vibration of the vibrator, and a secondary drive electrode that drives the vibrator so as to cancel the secondary vibration. The primary drive electrode is configured to be interchangeable with either the secondary drive electrode or the secondary detection electrode, and the primary detection electrode is configured to be interchangeable with the other of the secondary detection electrode or the secondary drive electrode. Electrical connections are set so that the potential difference between the electrodes to be interchanged and the surrounding electrodes is maintained before and after the interchange, based on the position of the electrodes to be interchanged and the direction of the current.

[0016] In the gyroscope according to the second aspect of the present invention, as described above, the primary drive electrode, the primary detection electrode, the secondary detection electrode, and the secondary drive electrode are configured such that, before and after the replacement, based on the positions of the electrodes to be replaced and the directions of the currents, the electrical connections are set so that the potential differences from the surrounding electrodes are maintained. As a result, the potential difference between the electrode responsible for a certain function and the surrounding electrodes can be made equal before and after the replacement. Therefore, the influence of the magnetic field due to the displacement current can be equally superimposed on the output signals before and after the replacement. Consequently, for example, when the output signals before and after the replacement are differentiated, the influence (bias component) of the magnetic field due to the displacement current can be sufficiently canceled (made zero or near zero). That is, in a configuration where replacement is performed, a gyroscope capable of sufficiently canceling the influence (bias component) of the magnetic field due to the displacement current can be provided. Further, since the influence (bias component) of the magnetic field due to the displacement current can be sufficiently canceled, the detection accuracy of the angular velocity can be improved in a gyroscope including a vibrating gyro element.

Advantages of the Invention

[0017] According to the present invention, as described above, in a configuration where replacement is performed, the influence of the magnetic field due to the displacement current can be sufficiently canceled.

Brief Description of the Drawings

[0018]

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[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0020] [First Embodiment] (Configuration of Vibration Type Gyro Element) With reference to FIGS. 1 to 11, a vibration type gyro element 100 and a gyroscope 101 including the vibration type gyro element 100 according to the first embodiment will be described.

[0021] In the following description, the radial direction of the vibrator 20 may be referred to as the radial direction, the outer circumferential direction of the vibrator 20 may be referred to as the circumferential direction, and the direction intersecting with the radial direction and the circumferential direction may be referred to as the axial direction, respectively. Further, in the radial direction, the center side of the vibrator 20 may be referred to as the inner or inner side, and the outer peripheral side may be referred to as the outer or outer side. In the axial direction, the side where the upper yoke 61 (see FIG. 2) is provided may be referred to as the upper or upper side, and the side where the lower yoke 63 (see FIG. 2) is provided may be referred to as the lower or lower side. Further, the upper surface of each member shown hereinafter may be referred to as the front surface, and the lower surface may be referred to as the back surface, respectively. Note that the radial direction does not necessarily require that the extended virtual line intersects the center of the vibrator 20. Also, the circumferential direction is not necessarily a curve with a constant curvature.

[0022] Also, one or more primary drive electrodes may be collectively referred to as the primary drive electrode PD, and one or more primary detection electrodes may be collectively referred to as the primary detection electrode PPO. Further, one or more secondary drive electrodes may be collectively referred to as the secondary drive electrode SD, and one or more secondary detection electrodes may be collectively referred to as the secondary detection electrode SPO.

[0023] As shown in FIGS. 1 and 2, the vibration type gyro element 100 includes a fixed portion 10, a vibrator 20, a plurality of support portions 30, a plurality of electrodes 40a to 40p, and a magnetic field applying portion 60. The vibration type gyro element 100 is a vibration type gyro element driven electromagnetically with the magnetic field applying portion 60.

[0024] As shown in FIG. 1, the fixed portion 10 has an opening 10a at the center. Inside the opening 10a, the vibrator 20, a plurality of support portions 30, a plurality of electrodes 40a to 40p, and the magnetic field applying portion 60 (see FIG. 2) are arranged. Further, as shown in FIG. 2, the fixed portion 10 is a member having a laminated structure in which a first silicon layer 51, a silicon oxide layer (insulating layer) 52, and a second silicon layer 53 are laminated in this order. Also, a silicon oxide film 54 is formed on the surface of the second silicon layer 53.

[0025] The vibrator 20 is a ring-shaped (annular) member obtained by processing the second silicon layer 53 and has a vibration mode of cosNθ. In the case of the vibrator 20 with N = 2 shown in FIG. 1, the primary vibration of the cos2θ mode is excited.

[0026] The support portion 30 is a member obtained by processing the second silicon layer 53 and is integrally formed with the vibrator 20. Further, the support portion 30 connects the vibrator 20 to the fixing portion 10 and supports the vibrator 20 in a cantilever manner. That is, the support portion 30 supports the vibrator 20 so as to be vibratable.

[0027] As shown in FIG. 3, each of the plurality of support portions 30 includes a first leg portion 31 and a second leg portion 32. Each of the first leg portion 31 and the second leg portion 32 has a first end portion 30a and a second end portion 30b. The first end portions 30a (two first end portions 30a) of the first leg portion 31 and the second leg portion 32 are respectively connected to different positions of the vibrator 20 with a first interval therebetween. The second end portions 30b (two second end portions 30b) of the first leg portion 31 and the second leg portion 32 are respectively connected to different positions of the fixing portion 10 with a second interval narrower than the first interval therebetween.

[0028] Further, the first leg portion 31 has a first portion 31a extending radially outward from the first end portion 30a of the vibrator 20, and a first bent portion 31b which is a bent portion at one end of the first portion 31a and extends in parallel with the outer periphery of the vibrator 20, and a second portion 31c. Further, the first leg portion 31 has a second bent portion 31d which is a bent portion at one end of the second portion 31c and extends radially outward from the vibrator 20 to reach the second end portion 30b, and a third portion 31e.

[0029] Similarly, the second leg portion 32 has a first portion 32a extending radially outward from the first end portion 30a of the vibrator 20, and a first bent portion 32b which is a bent portion at one end of the first portion 32a and extends in parallel with the outer periphery of the vibrator 20, and a second portion 32c. Further, the second leg portion 32 has a second bent portion 32d which is a bent portion at one end of the second portion 32c and extends radially outward from the vibrator 20 to reach the second end portion 30b, and a third portion 32e.

[0030] The second part 31c of the first leg portion 31 and the second part 32c of the second leg portion 32 each extend to the second bending portions 31d, 32d so as to approach each other. Further, the third part 31e of the first leg portion 31 and the third part 32e of the second leg portion 32 each extend from the second bending portions 31d, 32d to the second end portion 30b in parallel while leaving a predetermined interval therebetween. Further, the first leg portion 31 and the second leg portion 32 are symmetrically arranged with respect to a virtual line passing through the center of the vibrator 20 and between their respective third parts 31e, 32e.

[0031] Each of the electrodes 40a to 40p is a conductive member formed in a loop shape on the surface of the vibrator 20. Further, each of the electrodes 40a to 40p is formed so as to extend over the surfaces of the support portion 30 and the fixing portion 10. For example, as shown in FIG. 3, the electrode 40d extends from the second end portion 30b of the first leg portion 31, via the first leg portion 31, the vibrator 20 between the first end portion 30a, and the second leg portion 32, to the second end portion 30b of the second leg portion 32. Further, the electrode 40d is formed on the surface of the silicon oxide film 54. In the following description, when not particularly focusing on the arrangement and function of the electrodes, the electrodes 40a to 40p may be collectively referred to as the electrode 40.

[0032] The electrodes 40 are arranged in rows at intervals in the circumferential direction of the vibrator 20 on the surface of the vibrator 20. Further, a plurality of rows (two rows in the first embodiment) of the electrodes 40 are arranged in parallel at intervals in the circumferential direction of the vibrator 20 on the surface of the vibrator 20. The electrodes 40 include a primary drive electrode PD that excites a primary vibration in the cos2θ mode in the vibrator 20, a primary detection electrode PPO that detects the primary vibration, a secondary detection electrode SPO that detects a secondary vibration of the vibrator 20, and a secondary drive electrode SD that drives the vibrator 20 so as to cancel the secondary vibration. In the rows of the electrodes 40 arranged in at least one row or more (two rows in the first embodiment) at intervals in the circumferential direction of the vibrator 20 on the surface of the vibrator 20, there are included one or more (four each in the first embodiment) of the primary drive electrode PD, the primary detection electrode PPO, the secondary detection electrode SPO, and the secondary drive electrode SD.

[0033] Also, as shown in FIGS. 1 and 3, two electrodes 40 are formed on the surfaces of the support portion 30 and the vibrator 20 so as to extend in parallel with a space therebetween. For example, as shown in FIG. 3, on the surfaces of the support portion 30 and the vibrator 20, two electrodes 40d and 40l are formed so as to extend in parallel with a space therebetween. In the present specification, "in parallel" includes not only the case where two members are arranged parallel to each other, but also the case where two members are arranged with a space therebetween so that they do not contact or cross each other.

[0034] In FIG. 3, among the two electrodes 40d and 40l provided on the surface of one support portion 30 and arranged in parallel in a loop shape, the electrode 40d arranged on the outside is the primary drive electrode PD, and the electrode 40l arranged on the inside is the primary detection electrode PPO. Also, among the two electrodes 40e and 40m provided on the surface of the other support portion 30 and arranged in parallel in a loop shape, the electrode 40e arranged on the outside is the secondary drive electrode SD, and the electrode 40m arranged on the inside is the secondary detection electrode SPO. That is, the primary drive electrode PD and the primary detection electrode PPO are arranged in the same orientation, and the secondary drive electrode SD and the secondary detection electrode SPO are arranged in the same orientation.

[0035] As shown in FIG. 1, the primary drive electrodes PD are alternately arranged in the same column as the secondary drive electrodes SD, and the primary detection electrodes PPO are alternately arranged in the same column as the secondary detection electrodes SPO. That is, the set of the primary drive electrodes PD and the primary detection electrodes PPO and the set of the secondary drive electrodes SD and the secondary detection electrodes SPO are alternately arranged along the circumferential direction. Also, the set of the primary drive electrodes PD and the primary detection electrodes PPO and the set of the secondary drive electrodes SD and the secondary detection electrodes SPO are provided in the same number.

[0036] A set of a first primary drive electrode PD and a first primary detection electrode PPO, and a set of a first primary drive electrode PD and a first primary detection electrode PPO that are closest to it are arranged at positions 90 degrees apart from each other. A set of a first secondary drive electrode SD and a first secondary detection electrode SPO, and a set of a first secondary drive electrode SD and a first secondary detection electrode SPO that are closest to it are arranged at positions 90 degrees apart from each other. A set of a first primary drive electrode PD and a first primary detection electrode PPO, and a set of a first secondary drive electrode SD and a first secondary detection electrode SPO that are closest to it are arranged at positions 45 degrees apart from each other. Four each of the primary drive electrode PD, the primary detection electrode PPO, the secondary drive electrode SD, and the secondary detection electrode SPO are provided.

[0037] In addition, the four primary drive electrodes PD are electrically connected in series via electrode pads. Also, the four primary detection electrodes PPO are electrically connected in series via electrode pads. Also, the four secondary drive electrodes SD are electrically connected in series via electrode pads. Also, the four secondary detection electrodes SPO are electrically connected in series via electrode pads.

[0038] As shown in FIG. 2, the magnetic field application unit 60 includes an upper yoke 61, a magnet 62, and a lower yoke 63. The upper yoke 61 and the lower yoke 63 are each a bottomed cylindrical member made of a magnetic material such as iron. The upper yoke 61 and the lower yoke 63 are arranged such that the cylindrical portions of the upper yoke 61 and the lower yoke 63 face each other with an axial gap. Also, a vibrator 20 is arranged between the cylindrical portion of the upper yoke 61 and the cylindrical portion of the lower yoke 63. The vibrator 20 is arranged between the cylindrical portion of the upper yoke 61 and the cylindrical portion of the lower yoke 63 with an axial gap therebetween. In FIGS. 1 and 3, the illustration of the magnetic field application unit 60 is omitted.

[0039] One of the upper and lower parts of the magnet 62 is an N pole and the other is an S pole. The magnet 62 is held by the upper yoke 61 or the lower yoke 63, or both, and is fixedly arranged inside the vibrator 20 in the radial direction.

[0040] Magnetic flux flowing from one magnetic pole of the magnet 62 passes through one of the upper yoke 61 and the lower yoke 63, reaches the vibrator 20 and the electrodes 40a to 40p formed on its surface. Further, the magnetic flux passes through the vibrator 20 and the electrodes 40a to 40p, and flows into the other magnetic pole of the magnet 62 through the other of the upper yoke 61 and the lower yoke 63.

[0041] In this way, the magnetic field applying unit 60 applies a magnetic field to the plurality of electrodes 40a to 40p in a direction (in this case, the axial direction) intersecting the surface of the vibrator 20. Note that the magnetic field applying unit 60 is supported by a support substrate (not shown), thereby maintaining the radial and axial positions with respect to the vibrator 20.

[0042] The vibrating gyro element 100 excluding the magnetic field applying unit 60 is, for example, a MEMS (Micro Electro Mechanical Systems) element obtained by processing a known SOI (Silicon On Insulator) substrate using a micromachining technology applying semiconductor microfabrication technology.

[0043] This MEMS element is made as follows, for example. An SOI substrate having a first silicon layer 51, a silicon oxide layer 52, and a second silicon layer 53 is thermally oxidized to form a silicon oxide film 54 on the surface of the second silicon layer 53.

[0044] Next, a plurality of electrodes 40a to 40p are formed on the surface of the silicon oxide film 54 using a mask pattern (not shown). For example, a film of a conductive material such as aluminum is deposited on the surface of the silicon oxide film 54 through the mask pattern to form the plurality of electrodes 40a to 40p.

[0045] Using another mask pattern (not shown), the silicon oxide film 54 and the second silicon layer 53 are etched and removed until reaching the silicon oxide layer 52. Through this process, the prototypes of the support portion 30 and the vibrator 20 are formed.

[0046] Next, with the surfaces of the electrodes 40a to 40p, the support portion 30, and the vibrator 20 protected by wax or the like, a mask pattern (not shown) corresponding to the opening 10a of the fixing portion 10 is used to etch and remove the first silicon layer 51 located below the support portion 30 and the vibrator 20. Further, using the same mask pattern, the silicon oxide layer 52 is etched and removed to obtain the aforementioned MEMS element.

[0047] Note that the etching of the first silicon layer 51 and the silicon oxide layer 52 may be either dry etching or wet etching. However, in either case, it is preferable to use an etchant with high etching selectivity with respect to the layer underlying the etching layer.

[0048] (Configuration of Gyroscope) With reference to FIG. 4, a gyroscope 101 including a vibrating gyro element 100 will be described. For convenience of explanation, in FIG. 4, only the primary drive electrode PD, the primary detection electrode PPO, the secondary drive electrode SD, and the secondary detection electrode SPO among the vibrating gyro elements 100 are shown in a simplified manner.

[0049] As shown in FIG. 4, the gyroscope 101 includes a vibrating gyro element 100, a primary AC power supply 110, a primary detection unit 120, a secondary AC power supply 130, a secondary detection unit 140, an arithmetic unit 150, a switching unit 160, and a plurality of switches 170.

[0050] The primary AC power supply 110 is electrically connected to four serially connected primary drive electrodes PD. The primary detection unit 120 is electrically connected to four serially connected primary detection electrodes PPO. The secondary AC power supply 130 is electrically connected to four serially connected secondary drive electrodes SD. The secondary detection unit 140 is electrically connected to four serially connected secondary detection electrodes SPO. Further, the arithmetic unit 150 is electrically connected to the secondary AC power supply 130.

[0051] Hereinafter, the operation of the gyroscope 101 will be described.

[0052] When an alternating current Ip is supplied from an AC power source 110 to the primary drive electrode PD, a Lorentz force is applied to the primary drive electrode PD in directions intersecting with the direction of the magnetic field applied from the magnetic field application unit 60 and the direction in which the alternating current Ip flows, respectively. That is, the Lorentz force acts in a direction parallel to the surface of the vibrator 20. The vibrator 20 provided with the primary drive electrode PD deforms under this Lorentz force. Further, since the direction of the Lorentz force periodically reverses according to the frequency of the alternating current Ip, the vibrator 20 vibrates at the same frequency. In this case, the vibrator 20 vibrates in a direction parallel to its surface.

[0053] By setting the frequency of the alternating current Ip so as to match the resonance frequency of the vibrator 20, a primary vibration in the cos2θ mode is excited in the vibrator 20.

[0054] Also, an alternating current Ip is passed through each of the four primary drive electrodes PD so as to excite a primary vibration in the cos2θ mode in the vibrator 20. Specifically, between two primary drive electrodes PD located 90 degrees apart, the directions in which the alternating current Ip flows are set to be opposite to each other, that is, clockwise and counterclockwise when viewed from above.

[0055] The primary detection electrode PPO detects the primary vibration and generates a voltage signal having a magnitude corresponding to the amplitude thereof. This voltage signal is fed back to the primary detection unit 120. The primary detection unit 120 outputs an output signal to the primary AC power source 110 based on the voltage signal generated by the primary detection electrode PPO. Based on the output signal of the primary detection unit 120, the primary AC power source 110, specifically, the amplitude and frequency of the alternating current Ip are controlled so that the vibration frequency and amplitude of the vibrator 20 become constant.

[0056] As shown in Fig. 5, the annular vibrator 20 vibrates primarily in a periodic elliptical shape with major axes orthogonal to each other. On the other hand, when a Coriolis force is applied to the vibrator 20 and an angular velocity is generated around the axial direction, the direction of the major axis of the aforementioned ellipse changes. In the case of the vibration type gyro element 100 of the present embodiment shown in Fig. 1, as shown in Fig. 6, with respect to the case of primary vibration, the major axis of the ellipse changes to a position rotated by 45 degrees, and the vibrator 20 enters a secondary vibration state.

[0057] A magnetic field is also applied to the secondary detection electrode SPO in a direction intersecting its surface. Further, in response to the vibration of the vibrator 20, the secondary detection electrode SPO also vibrates in a direction parallel to its surface. Due to these factors, a sinusoidal alternating voltage corresponding to the magnetic field intensity and the moving speed during vibration is generated in the secondary detection electrode SPO. Also, since the moving speed of the secondary detection electrode SPO is different between the case where the vibrator 20 is in the primary vibration state and the case where it is in the secondary vibration state, the voltages generated in each state are also different.

[0058] The secondary detection unit 140 detects the voltage generated in the secondary detection electrode SPO and outputs an output signal corresponding to the magnitude of this voltage to the secondary AC power supply 130.

[0059] The output signal of the secondary detection unit 140 is input to the secondary AC power supply 130. The secondary AC power supply 130 supplies an alternating current to the secondary drive electrode SD to drive the vibrator 20 so as to cancel the secondary vibration generated in the vibrator 20 based on this output signal. Also, the secondary AC power supply 130 inputs an output signal based on the output current to the arithmetic unit 150.

[0060] The arithmetic unit 150 determines whether the vibrator 20 is in the primary vibration state or the secondary vibration state based on the output signal of the secondary AC power supply 130. Also, when it is determined that the vibrator 20 is in the secondary vibration state, the arithmetic unit 150 calculates the angular velocity based on the output signal of the secondary AC power supply 130.

[0061] Further, the vibratory gyro element 100 is configured such that the primary drive electrode PD and the secondary drive electrode SD can be swapped, and the primary detection electrode PPO and the secondary detection electrode SPO can be swapped. The gyroscope 101 performs the swapping at a predetermined timing, acquires the output signals from the vibratory gyro element 100 before and after the swapping, and calculates the angular velocity based on these output signals by the arithmetic unit 150. For example, the arithmetic unit 150 calculates the angular velocity based on the difference between the output signals before and after the swapping. This swapping is performed by switching the internal connections by the switch 170 and the switching unit 160 shown in FIG. 4. Note that as the "predetermined timing", cases where the vibratory gyro element 100 is in a stationary state or a constant velocity motion state are selected.

[0062] The electrode arrangement shown in FIG. 7 is the electrode arrangement before the swapping, and is the same as that shown in FIG. 1. That is, the electrodes 40b, 40d, 40f, 40h are electrically connected to the primary AC power supply 110 and function as the primary drive electrode PD. Also, the electrodes 40j, 40l, 40n, 40p are electrically connected to the primary detection unit 120 and function as the primary detection electrode PPO. Further, the electrodes 40a, 40c, 40e, 40g are electrically connected to the secondary AC power supply 130 and function as the secondary drive electrode SD. Also, the electrodes 40i, 40k, 40m, 40o are electrically connected to the secondary detection unit 140 and function as the secondary detection electrode SPO.

[0063] At a predetermined timing, by sending a control signal from the switching unit 160 to the four switches 170, the internal connections of the gyroscope 101 are switched. As a result, the electrode arrangement is switched to the electrode arrangement after the swapping shown in FIG. 8. Specifically, the electrodes 40b, 40d, 40f, 40h are electrically connected to the secondary AC power supply 130 and function as the secondary drive electrode SD. Similarly, the electrodes 40j, 40l, 40n, 40p are electrically connected to the secondary detection unit 140 and function as the secondary detection electrode SPO. The electrodes 40a, 40c, 40e, 40g are connected to the primary AC power supply 110 and function as the primary drive electrode PD. The electrodes 40i, 40k, 40m, 40o are connected to the primary detection unit 120 and function as the primary detection electrode PPO.

[0064] Note that the vibration type gyro element 100, the primary AC power supply 110, the primary detection unit 120, the secondary AC power supply 130, the secondary detection unit 140, and the calculation unit 150 may be mounted on separate substrates or on the same substrate. The vibration type gyro element 100, the primary AC power supply 110, the primary detection unit 120, the secondary AC power supply 130, the secondary detection unit 140, and the calculation unit 150 may be housed in separate packages (not shown). Further, the vibration type gyro element 100 and other components may be mounted on separate substrates or housed in separate packages. In that case, the primary AC power supply 110 and the secondary AC power supply 130 may be further mounted on separate substrates or housed in separate packages.

[0065] (Electrical connection of electrodes) Here, in the first embodiment, as shown in FIGS. 9 and 10, the primary drive electrode PD, the primary detection electrode PPO, the secondary detection electrode SPO, and the secondary drive electrode SD are electrically connected so that the potential difference from the surrounding electrodes 40 is maintained based on the position and current direction of the electrode 40 to be swapped before and after the swap. Specifically, the primary drive electrode PD, the primary detection electrode PPO, the secondary detection electrode SPO, and the secondary drive electrode SD satisfy the conditions including that the position and function (role) of the surrounding electrodes 40 are the same, the position and current direction of the surrounding electrodes 40 are the same, and the order of electrical connection for each function of the surrounding electrodes 40 is the same, based on the position and current direction of the electrode 40 to be swapped before and after the swap. In FIGS. 9 and 10, for convenience, only the function of the electrode 40, the current direction of the electrode 40, and the order of electrical connection of the electrode 40 are illustrated. Also, since the current of the electrode 40 is an alternating current, the current direction and the order of electrical connection of the electrode 40 periodically change, but the current direction and the order of electrical connection at a predetermined time point are shown.

[0066] Also, in FIGS. 9 and 10, the direction of the current in the electrode 40 is indicated by the arrows of solid lines, broken lines, one-dot chain lines, or two-dot chain lines. The order of the electrical connections of the electrode 40 is indicated by attaching numbers within the circles of solid lines, broken lines, one-dot chain lines, or two-dot chain lines. The order of the electrical connections of the electrode 40 is 4 → 3 → 2 → 1. Number 4 is the most upstream side, and number 1 is the most downstream side. That is, number 4 has the highest potential, and number 1 has the lowest potential.

[0067] In FIG. 9, four primary drive electrodes PD are electrically connected in the order of the primary drive electrode PD of number 4, the primary drive electrode PD of number 3, the primary drive electrode PD of number 2, and the primary drive electrode PD of number 1, and current flows in this order. The same applies to the secondary drive electrode SD, the primary detection electrode PPO, and the secondary detection electrode SPO. The same also applies to the primary drive electrode PD, the secondary drive electrode SD, the primary detection electrode PPO, and the secondary detection electrode SPO shown in FIG. 10.

[0068] Also, focusing on the electrode 40 itself rather than the function of the electrode 40, the electrodes 40b, 40d, 40f, 40h are electrically connected in series in this order, and current flows in this order. Also, the electrodes 40e, 40c, 40a, 40g are electrically connected in series in this order, and current flows in this order. Also, the electrodes 40l, 40n, 40p, 40j are electrically connected in series in this order, and current flows in this order. Also, the electrodes 40k, 40i, 40o, 40m are electrically connected in series in this order, and current flows in this order. In the first embodiment, reverse currents flow in two electrodes 40 (such as the electrodes 40b and 40j) that are parallel to each other.

[0069] Here, in FIGS. 9 and 10, the principle by which the potential difference between the electrode 40 having a certain function and the surrounding electrodes 40 is maintained before and after the replacement will be described.

[0070] For example, focusing on the 4th primary drive electrode PD, before the replacement, on the radially outer portion of the same vibrator 20 as the 4th primary drive electrode PD, there is the 1st primary detection electrode PPO through which a current flows in the reverse direction. On the tip side in the direction of the current of the 4th primary drive electrode PD, there are the 3rd secondary drive electrode SD through which a current flows in the same direction radially inward and the 4th secondary detection electrode SPO through which a current flows in the reverse direction radially outward. On the base end side in the direction of the current of the 4th primary drive electrode PD, there are the 2nd secondary drive electrode SD through which a current flows in the reverse direction radially inward and the 3rd secondary detection electrode SPO through which a current flows in the same direction radially outward.

[0071] Also, after the replacement, the 4th primary drive electrode PD is replaced to a position radially inward that has rotated 135 degrees clockwise, and the direction of the current reverses before and after the replacement. Also, even after the replacement, on the radially outer portion of the same vibrator 20 as the 4th primary drive electrode PD, there is the 1st primary detection electrode PPO through which a current flows in the reverse direction to the 4th primary drive electrode PD. On the tip side in the direction of the current of the 4th primary drive electrode PD, there are the 3rd secondary drive electrode SD through which a current flows in the same direction radially inward and the 4th secondary detection electrode SPO through which a current flows in the reverse direction radially outward. On the base end side in the direction of the current of the 4th primary drive electrode PD, there are the 2nd secondary drive electrode SD through which a current flows in the reverse direction radially inward and the 3rd secondary detection electrode SPO through which a current flows in the same direction radially outward.

[0072] That is, around the fourth primary drive electrode PD, electrodes 40 (the first primary detection electrode PPO, the third secondary drive electrode SD, the fourth secondary detection electrode SPO, the second secondary drive electrode SD, the third secondary detection electrode SPO) with the same potential exist before and after the replacement. Therefore, the potential difference between the fourth primary drive electrode PD and the surrounding electrodes 40 is the same before and after the replacement. At this time, the fourth primary drive electrode PD satisfies the conditions including that the position and function of the surrounding electrodes 40 are the same, the position and current direction of the surrounding electrodes 40 are the same, and the electrical connection order for each function of the surrounding electrodes 40 is the same, based on the position and current direction of the electrode 40 (the fourth primary drive electrode PD) to be replaced before and after the replacement.

[0073] Although the electrodes 40 (the first primary detection electrode PPO, the third secondary drive electrode SD, the fourth secondary detection electrode SPO, the second secondary drive electrode SD, the third secondary detection electrode SPO) at positions close to the fourth primary drive electrode PD have been described, the fourth primary drive electrode PD also satisfies the above conditions for the electrodes 40 other than those at close positions.

[0074] Also, although the fourth primary drive electrode PD has been described, the other primary drive electrodes PD, secondary drive electrodes SD, primary detection electrodes PPO, and secondary detection electrodes SPO also satisfy the above conditions. Therefore, in any of the four primary drive electrodes PD, four secondary drive electrodes SD, four primary detection electrodes PPO, and four secondary detection electrodes SPO, the potential difference from the surrounding electrodes 40 is the same before and after the replacement.

[0075] In the first embodiment, the positions of the electrodes 40 on the surface of the vibrator 20 among the primary drive electrode PD, primary detection electrode PPO, secondary detection electrode SPO, and secondary drive electrode SD, the current direction of the electrodes 40, and the electrical connection order for each function of the electrodes 40 are set to be line-symmetric with respect to the virtual symmetry axis As to the positions, current directions, and electrical connection orders for each function of the electrodes 40 on the surface of the vibrator 20 that are set as the ones to be replaced.

[0076] For example, focus on the fourth primary drive electrode PD. The position that is line-symmetric with respect to the virtual symmetry axis As of the fourth primary drive electrode PD before the replacement is a position rotated 135 degrees clockwise, which is the angle for detecting / canceling the secondary vibration. Therefore, the secondary drive electrode SD or the secondary detection electrode SPO must be arranged. Also, at this position, the direction of the current is reversed (line-symmetric), and the connection order for each function is set to be the same (line-symmetric). Specifically, the positions on the surface of the vibrator 20 of the electrodes 40b and 40e that are set as the replacement partners are line-symmetric with respect to the virtual symmetry axis As. Also, the direction of the current flowing through the electrode 40b and the direction of the current flowing through the electrode 40e are opposite, and the direction of the current is line-symmetric with respect to the virtual symmetry axis As. Also, both the electrode 40b and the electrode 40e have the same connection order number 4 for electrical connection, and the electrical connection order can be said to be line-symmetric with respect to the virtual symmetry axis As. Note that the same applies to the other primary drive electrodes PD, secondary drive electrodes SD, primary detection electrodes PPO, and secondary detection electrodes SPO other than the fourth primary drive electrode PD.

[0077] Also, the current inflow points P11 to P14 and the current outflow points P21 to P24 are also line-symmetric with respect to the virtual symmetry axis As before and after the replacement.

[0078] The inflow point P11 serves as the inflow point of current into the current path formed by the four primary drive electrodes PD before the switching, and becomes the inflow point of current into the current path formed by the four secondary drive electrodes SD after the switching. Similarly, the inflow point P12 serves as the inflow point of current into the current path formed by the four secondary drive electrodes SD before the switching, and becomes the inflow point of current into the current path formed by the four primary drive electrodes PD after the switching. Also, the inflow point P13 serves as the inflow point of current into the current path formed by the four primary detection electrodes PPO before the switching, and becomes the inflow point of current into the current path formed by the four secondary detection electrodes SPO after the switching. Additionally, the inflow point P14 serves as the inflow point of current into the current path formed by the four secondary detection electrodes SPO before the switching, and becomes the inflow point of current into the current path formed by the four primary detection electrodes PPO after the switching.

[0079] For example, the inflow point P11, which is the inflow point of current into the current path formed by the four primary drive electrodes PD before the switching, and the inflow point P12, which is the inflow point of current into the current path formed by the four primary drive electrodes PD after the switching, are line-symmetric with respect to the virtual symmetry axis As. That is, the inflow point P12, which is the inflow point of current into the current path formed by the four secondary drive electrodes SD before the switching, and the inflow point P11, which is the inflow point of current into the current path formed by the four secondary drive electrodes SD after the switching, are line-symmetric with respect to the virtual symmetry axis As. The same applies to the inflow points P13 and 14 (and also to the primary detection electrodes PPO and secondary detection electrodes SPO).

[0080] Also, the outflow point P21 is the outflow point of current from the current path by the four primary drive electrodes PD before the switching, and becomes the outflow point of current from the current path by the four secondary drive electrodes SD after the switching. Similarly, the outflow point P22 is the outflow point of current from the current path by the four secondary drive electrodes SD before the switching, and becomes the outflow point of current from the current path by the four primary drive electrodes PD after the switching. Further, the outflow point P23 is the outflow point of current from the current path by the four primary detection electrodes PPO before the switching, and becomes the outflow point of current from the current path by the four secondary detection electrodes SPO after the switching. Also, the outflow point P24 is the outflow point of current from the current path by the four secondary detection electrodes SPO before the switching, and becomes the outflow point of current from the current path by the four primary detection electrodes PPO after the switching.

[0081] For example, the outflow point P21, which is the outflow point of current to the current path by the four primary drive electrodes PD before the switching, and the outflow point P22, which is the outflow point of current to the current path by the four primary drive electrodes PD after the switching, are line-symmetric with respect to the virtual symmetry axis As. That is, the outflow point P22, which is the outflow point of current to the current path by the four secondary drive electrodes SD before the switching, and the outflow point P21, which is the outflow point of current to the current path by the four secondary drive electrodes SD after the switching, are line-symmetric with respect to the virtual symmetry axis As. The same applies to the outflow points P23 and 24 (and also to the primary detection electrodes PPO and the secondary detection electrodes SPO).

[0082] The inflow points P11 to P14 are also the inflow point P11 of current to the current path by the electrodes 40b, 40d, 40f, 40h, the inflow point P12 of current to the current path by the electrodes 40e, 40c, 40a, 40g, the inflow point P13 of current to the current path by the electrodes 40l, 40n, 40p, 40j, and the inflow point P14 of current to the current path by the electrodes 40k, 40i, 40o, 40m. The inflow points P11 and P14, and the inflow points P12 and P13 are line-symmetric with respect to the virtual symmetry axis As.

[0083] Also, the current outflow points P21 to P24 are the current outflow point P21 from the current path by the electrodes 40b, 40d, 40f, 40h, the current outflow point P22 from the current path by the electrodes 40e, 40c, 40a, 40g, the current outflow point P23 from the current path by the electrodes 40l, 40n, 40p, 40j, and the current outflow point P24 from the current path by the electrodes 40k, 40i, 40o, 40m. With respect to the virtual symmetry axis As, the outflow points P21 and P23, and the outflow points P22 and P24 are line-symmetric.

[0084] The virtual symmetry axis As is an axis that passes through the center of the vibrator 20 and the center between the electrodes 40 and extends in the radial direction. In FIGS. 9 and 10, the virtual symmetry axis As passes through the center of the vibrator 20 and the center between the primary drive electrode PD and the secondary drive electrode SD (between the primary detection electrode PPO and the secondary detection electrode SPO) that are interchanged with each other and extends in the radial direction. Also, the virtual symmetry axis As passes through the center of the vibrator 20, the center between the electrodes 40c and 40d (between the electrodes 40k and 40l), and the center between the electrodes 40g and 40h (between the electrodes 40o and 40p) and extends in the radial direction. When one of the primary drive electrode PD and the secondary drive electrode SD or the secondary detection electrode SPO is alternately arranged, and the other of the primary detection electrode PPO and the secondary drive electrode SD or the secondary detection electrode SPO is alternately arranged, the virtual symmetry axis As can be set between any electrodes, and it may be set so that the direction of the current and the order of the electrical connections for each function are line-symmetric with respect to the set virtual symmetry axis As.

[0085] In the first embodiment, the primary drive electrode PD, the primary detection electrode PPO, the secondary detection electrode SPO, and the secondary drive electrode SD are each electrically connected in the clockwise order or the counterclockwise order according to each function. In FIG. 9, the primary drive electrode PD is electrically connected in the clockwise order, and in FIG. 10, the primary drive electrode PD is electrically connected in the counterclockwise order. Further, in FIG. 9, the secondary drive electrode SD is electrically connected in the counterclockwise order, and in FIG. 10, the secondary drive electrode SD is electrically connected in the clockwise order. Further, in FIG. 9, the primary detection electrode PPO is electrically connected in the clockwise order, and in FIG. 10, the primary detection electrode PPO is electrically connected in the counterclockwise order. Further, in FIG. 9, the secondary detection electrode SPO is electrically connected in the counterclockwise order, and in FIG. 10, the secondary detection electrode SPO is electrically connected in the clockwise order.

[0086] Further, the electrodes 40b, 40d, 40f, and 40h are electrically connected in the clockwise order. Further, the electrodes 40e, 40c, 40a, and 40g are electrically connected in the counterclockwise order. Further, the electrodes 40l, 40n, 40p, and 40j are electrically connected in the clockwise order. Further, the electrodes 40k, 40i, 40o, and 40m are electrically connected in the counterclockwise order.

[0087] (Details of Electrical Connection of Electrodes) With reference to FIG. 11, the details of the electrical connection of the electrode 40 will be described.

[0088] First, the electrical connection of the electrodes 40b, 40d, 40f, and 40h will be described. The fourth electrode 40b and the third electrode 40d are electrically connected by wiring on the vibration type gyro element 100. The third electrode 40d and the second electrode 40f are electrically connected by wiring on the substrate side. The second electrode 40f and the first electrode 40h are electrically connected by wiring on the vibration type gyro element 100. Note that the electrical connection method is not particularly limited, such as metal wiring via an insulating film and wire bonding.

[0089] Specifically, as shown in FIG. 11, one end of the electrode 40b is electrically connected to the electrode pad 71a via the wiring 71b. The electrode pad 71a is electrically connected to the primary AC power supply 110 before the replacement and is electrically connected to the secondary AC power supply 130 after the replacement. The other end of the electrode 40b is electrically connected to one end of the electrode 40d via the wiring 71c.

[0090] The other end of the electrode 40d is electrically connected to the electrode pad 71e via the wiring 71d. The electrode pad 71e is electrically connected to the electrode pad 71f via the wiring on the substrate side. The electrode pad 71f is electrically connected to one end of the electrode 40f via the wiring 71g. The other end of the electrode 40f is electrically connected to one end of the electrode 40h via the wiring 71h. The other end of the electrode 40h is electrically connected to the electrode pad 71j via the wiring 71i. The electrode pad 71j is electrically connected to the primary AC power supply 110 before the replacement and is electrically connected to the secondary AC power supply 130 after the replacement. In this way, the electrodes 40b, 40d, 40f, and 40h are electrically connected.

[0091] Next, the electrical connection of the electrodes 40e, 40c, 40a, and 40g will be described. The fourth electrode 40e and the third electrode 40c are electrically connected by the wiring on the vibration type gyro element 100. The third electrode 40c and the second electrode 40a are electrically connected by the wiring on the substrate side. The second electrode 40a and the first electrode 40g are electrically connected by the wiring on the vibration type gyro element 100.

[0092] Specifically, one end of the electrode 40e is electrically connected to the electrode pad 72a via the wiring 72b. The electrode pad 72a is electrically connected to the secondary AC power supply 130 before the replacement and is electrically connected to the primary AC power supply 110 after the replacement. The other end of the electrode 40e is electrically connected to the electrode pad 72d via the wiring 72c. The electrode pad 72d is electrically connected to the electrode pad 72f via the wiring 72e. The electrode pad 72f is electrically connected to one end of the electrode 40c via the wiring 72g.

[0093] The other end of the electrode 40c is electrically connected to the electrode pad 72i via the wiring 72h. The electrode pad 72i is electrically connected to the electrode pad 72j via the wiring on the substrate side. The electrode pad 72j is electrically connected to one end of the electrode 40a via the wiring 72k. The other end of the electrode 40a is electrically connected to the electrode pad 72m via the wiring 72l. The electrode pad 72m is electrically connected to the electrode pad 72o via the wiring 72n. The electrode pad 72o is electrically connected to one end of the electrode 40g via the wiring 72p. The other end of the electrode 40g is electrically connected to the electrode pad 72r via the wiring 72q. The electrode pad 72r is electrically connected to the secondary AC power supply 130 before the replacement and is electrically connected to the primary AC power supply 110 after the replacement. Thus, the electrodes 40e, 40c, 40a, and 40g are electrically connected.

[0094] Next, the electrical connection of the electrodes 40l, 40n, 40p, and 40j will be described. The fourth electrode 40l and the third electrode 40n are electrically connected by the wiring on the vibration type gyro element 100. The third electrode 40n and the second electrode 40p are electrically connected by the wiring on the substrate side. The second electrode 40p and the first electrode 40j are electrically connected by the wiring on the vibration type gyro element 100.

[0095] Specifically, one end of the electrode 40l is electrically connected to the electrode pad 73a via the wiring 73b. The electrode pad 73a is electrically connected to the primary detection unit 120 before the replacement and is electrically connected to the secondary detection unit 140 after the replacement. The other end of the electrode 40l is electrically connected to the electrode pad 73d via the wiring 73c. The electrode pad 73d is electrically connected to the electrode pad 73f via the wiring 73e. The electrode pad 73f is electrically connected to one end of the electrode 40n via the wiring 73g.

[0096] The other end of electrode 40n is electrically connected to electrode pad 73i via wiring 73h. Electrode pad 73i is electrically connected to electrode pad 73j via the wiring on the substrate side. Electrode pad 73j is electrically connected to one end of electrode 40p via wiring 73k. The other end of electrode 40p is electrically connected to electrode pad 73m via wiring 73l. Electrode pad 73m is electrically connected to electrode pad 73o via wiring 73n. Electrode pad 73o is electrically connected to one end of electrode 40j via wiring 73p. The other end of electrode 40j is electrically connected to electrode pad 73r via wiring 73q. Electrode pad 73r is electrically connected to the primary detection unit 120 before the replacement and is electrically connected to the secondary detection unit 140 after the replacement. In this way, electrodes 40l, 40n, 40p, and 40j are electrically connected.

[0097] Next, the electrical connections of electrodes 40k, 40i, 40o, and 40m will be described. The fourth electrode 40k and the third electrode 40i are electrically connected by the wiring on the vibration type gyro element 100. The third electrode 40i and the second electrode 40o are electrically connected by the wiring on the substrate side. The second electrode 40o and the first electrode 40m are electrically connected by the wiring on the vibration type gyro element 100.

[0098] Specifically, one end of electrode 40k is electrically connected to electrode pad 74a via wiring 74b. Electrode pad 74a is electrically connected to the secondary detection unit 140 before the replacement and is electrically connected to the primary detection unit 120 after the replacement. The other end of electrode 40k is electrically connected to electrode pad 74d via wiring 74c. Electrode pad 74d is electrically connected to electrode pad 74f via wiring 74e. Electrode pad 74f is electrically connected to one end of electrode 40i via wiring 74g.

[0099] The other end of the electrode 40i is electrically connected to the electrode pad 74i via the wiring 74h. The electrode pad 74i is electrically connected to the electrode pad 74j via the wiring on the substrate side. The electrode pad 74j is electrically connected to one end of the electrode 40o via the wiring 74k. The other end of the electrode 40o is electrically connected to the electrode pad 74m via the wiring 74l. The electrode pad 74m is electrically connected to the electrode pad 74o via the wiring 74n. The electrode pad 74o is electrically connected to one end of the electrode 40m via the wiring 74p. The other end of the electrode 40m is electrically connected to the electrode pad 74r via the wiring 74q. The electrode pad 74r is electrically connected to the secondary detection unit 140 before the replacement and is electrically connected to the primary detection unit 120 after the replacement. Thus, the electrodes 40k, 40i, 40o, and 40m are electrically connected.

[0100] (Effect of the First Embodiment) In the first embodiment, the following effects can be obtained.

[0101] In the first embodiment, as described above, the vibration type gyro element 100 is a vibration type gyro element by electromagnetic drive, and includes a fixed portion 10, a vibrator 20, a support portion 30 that connects the vibrator 20 and the fixed portion 10 and supports the vibrator 20 so as to be vibratable, a plurality of electrodes 40 arranged in rows at intervals in the circumferential direction of the vibrator 20 on the surface of the vibrator 20, and a magnetic field applying portion 60 that applies a magnetic field to the electrodes 40. The vibrator 20 has a vibration mode of cosNθ (N is a natural number of 2 or more). The electrodes 40 include a primary drive electrode PD that excites a primary vibration of the vibrator 20, a primary detection electrode PPO that detects the primary vibration, a secondary detection electrode SPO that detects a secondary vibration of the vibrator 20, and a secondary drive electrode SD that drives the vibrator 20 so as to cancel the secondary vibration. The primary drive electrode PD and the secondary drive electrode SD are interchangeable, and the primary detection electrode PPO and the secondary detection electrode SPO are interchangeable. The electrical connection is set so that the potential difference between the electrodes 40 to be interchanged and the surrounding electrodes 40 is maintained based on the position and current direction of the electrodes 40 to be interchanged before and after the interchange.

[0102] With the above configuration, the potential difference between the electrode 40 having a certain function and the surrounding electrodes 40 can be made equal before and after the interchange, so that the influence of the magnetic field due to the displacement current can be equally superimposed on the output signals before and after the interchange. As a result, for example, when the output signals before and after the interchange are differentiated, the influence (bias component) of the magnetic field due to the displacement current can be sufficiently canceled (made zero or near zero). That is, in the configuration where the interchange is performed, the influence (bias component) of the magnetic field due to the displacement current can be sufficiently canceled. Further, since the influence (bias component) of the magnetic field due to the displacement current can be sufficiently canceled, the detection accuracy of the angular velocity can be improved in the gyroscope 101 including the vibration type gyro element 100.

[0103] In the first embodiment, as described above, the primary drive electrode PD, the primary detection electrode PPO, the secondary detection electrode SPO, and the secondary drive electrode SD satisfy the conditions including that, before and after the replacement, the position and current direction of the electrodes to be replaced are used as references, the position and function of the surrounding electrodes 40 are the same, the position and current direction of the surrounding electrodes 40 are the same, and the electrical connection order for each function of the surrounding electrodes 40 is the same. Thus, the electrical connection is set. As a result, the potential difference between the electrode 40 with a certain function and the surrounding electrodes 40 can be easily made equal before and after the replacement, so that the influence (bias component) due to the magnetic field from the displacement current can be easily and sufficiently canceled.

[0104] In the first embodiment, as described above, the positions of the electrodes 40 on the surface of the vibrator 20 among the primary drive electrode PD, the primary detection electrode PPO, the secondary detection electrode SPO, and the secondary drive electrode SD, the current direction of the electrodes 40, and the electrical connection order for each function of the electrodes 40 are set to be line-symmetric with respect to the virtual symmetry axis As passing through the center of the vibrator 20 and extending in the radial direction of the vibrator 20, with respect to the positions on the surface of the vibrator of the electrodes to be set as the replacement partners, the current direction, and the electrical connection order for each function of the electrodes 40. As a result, a configuration can be realized in which the potential difference between the electrode 40 with a certain function and the surrounding electrodes 40 is made equal without changing the current direction and the electrical connection order of the electrodes 40 for each function (that is, without changing the current path for each function) before and after the replacement. Consequently, different from the case of realizing a configuration in which the potential difference between the electrode 40 with a certain function and the surrounding electrodes 40 is made equal by changing at least one of the current direction and the electrical connection order of the electrodes 40 for each function (that is, by changing the current path for each function) before and after the replacement, there is no need to provide a structure such as a switch for changing the current path. Thus, a structure for making the potential difference between the electrode 40 with a certain function and the surrounding electrodes 40 equal before and after the replacement can be realized with a simple structure.

[0105] In the first embodiment, as described above, a plurality of rows of electrodes 40 are arranged on the surface of the vibrator 20 in the circumferential direction of the vibrator 20 with a space therebetween in parallel. Thereby, a plurality of rows of electrodes 40 can be easily arranged on the surface of the vibrator 20.

[0106] In the first embodiment, as described above, the primary drive electrode PD is alternately arranged in the same row as either one of the secondary detection electrode SPO or the secondary drive electrode SD, and the primary detection electrode PPO is alternately arranged in the same row as the other of the secondary detection electrode SPO or the secondary drive electrode SD. Thereby, a set of the primary drive electrode PD and either one of the secondary detection electrode SPO or the secondary drive electrode SD that are interchanged with each other can be collected in the same row, and a set of the primary detection electrode PPO and the other of the secondary detection electrode SPO or the secondary drive electrode SD that are interchanged with each other can be collected in the same row. Therefore, the electrodes 40 of the primary drive electrode PD, the primary detection electrode PPO, the secondary detection electrode SPO, and the secondary drive electrode SD can be arranged in a well-balanced manner. Further, since the electrodes 40 of the primary drive electrode PD, the primary detection electrode PPO, the secondary detection electrode SPO, and the secondary drive electrode SD are alternately arranged, a virtual symmetry axis As can be easily provided.

[0107] In the first embodiment, as described above, the primary drive electrode PD, the primary detection electrode PPO, the secondary detection electrode SPO, and the secondary drive electrode SD are electrically connected in the clockwise order or the counterclockwise order for each function. Thereby, the structure of the wiring for electrically connecting between the electrodes 40 can be simplified in each of the electrodes 40 of the primary drive electrode PD, the primary detection electrode PPO, the secondary detection electrode SPO, and the secondary drive electrode SD.

[0108] [Second Embodiment] Next, with reference to FIGS. 12 to 15, the configuration of the vibration type gyro element 200 according to the second embodiment will be described. In the second embodiment, unlike the first embodiment in which the primary drive electrode PD, the primary detection electrode PPO, the secondary detection electrode SPO, and the secondary drive electrode SD are provided in four directions, an example in which the primary drive electrode PD, the primary detection electrode PPO, the secondary detection electrode SPO, and the secondary drive electrode SD are provided in two directions will be described. Note that the same components as those in the first embodiment are denoted by the same reference numerals in the drawings, and detailed descriptions thereof are omitted.

[0109] As shown in FIGS. 12 and 13, the vibration type gyro element 200 according to the second embodiment is different from the vibration type gyro element 100 of the first embodiment in that it includes electrodes 40a to 40h and does not include electrodes 40i to 40p. That is, the vibration type gyro element 200 is different from the vibration type gyro element 100 of the first embodiment in that one electrode 40 is formed on one support portion 30 instead of two electrodes 40 being formed on one support portion 30.

[0110] In the second embodiment, before the replacement, the serially connected electrodes 40b and 40f are electrically connected to the primary AC power supply 110 and function as the primary drive electrode PD, the serially connected electrodes 40c and 40g are electrically connected to the secondary AC power supply 130 and function as the secondary drive electrode SD, the serially connected electrodes 40d and 40h are electrically connected to the primary detection unit 120 and function as the primary detection electrode PPO, and the serially connected electrodes 40a and 40e are electrically connected to the secondary detection unit 140 and function as the secondary detection electrode SPO.

[0111] Also, after the replacement, the serially connected electrodes 40b and 40f are electrically connected to the secondary AC power supply 130 and function as the secondary drive electrode SD, the serially connected electrodes 40c and 40g are electrically connected to the primary AC power supply 110 and function as the primary drive electrode PD, the serially connected electrodes 40d and 40h are electrically connected to the secondary detection unit 140 and function as the secondary detection electrode SPO, and the serially connected electrodes 40a and 40e are electrically connected to the primary detection unit 120 and function as the primary detection electrode PPO.

[0112] The two primary drive electrodes PD, the two secondary drive electrodes SD, the two primary detection electrodes PPO, and the two secondary detection electrodes SPO are arranged at positions 180 degrees apart from each other.

[0113] Here, in the second embodiment, as shown in FIGS. 14 and 15, the primary drive electrode PD, the primary detection electrode PPO, the secondary detection electrode SPO, and the secondary drive electrode SD are electrically connected so that the potential difference from the surrounding electrodes 40 is maintained before and after the replacement, based on the position and current direction of the electrode 40 to be replaced. Specifically, the primary drive electrode PD, the primary detection electrode PPO, the secondary detection electrode SPO, and the secondary drive electrode SD are such that before and after the replacement, based on the position and current direction of the electrode 40 to be replaced, the position and function of the surrounding electrodes 40 are the same, the position and current direction of the surrounding electrodes 40 are the same, and the electrical connection order for each position and function of the surrounding electrodes 40 is the same. The electrical connection is set to satisfy the conditions including these. In FIGS. 14 and 15, the electrical connection order of the electrodes 40 is in the order of 2→1. The 2nd is the most upstream side, and the 1st is the most downstream side. That is, the 2nd has the highest potential, and the 1st has the lowest potential.

[0114] In FIG. 14, the two primary drive electrodes PD are electrically connected in the order of the 2nd primary drive electrode PD and the 1st primary drive electrode PD, and current flows in this order. The same applies to the secondary drive electrode SD, the primary detection electrode PPO, and the secondary detection electrode SPO. The same also applies to the primary drive electrode PD, the secondary drive electrode SD, the primary detection electrode PPO, and the secondary detection electrode SPO shown in FIG. 15.

[0115] Also, focusing on the electrode 40 itself rather than its function, electrodes 40b and 40f are electrically connected in series in this order, and current flows in this order. Also, electrodes 40c and 40g are electrically connected in series in this order, and current flows in this order. Also, electrodes 40a and 40e are electrically connected in series in this order, and current flows in this order. Also, electrodes 40d and 40h are electrically connected in series in this order, and current flows in this order.

[0116] Here, in FIGS. 14 and 15, the principle by which the potential difference between the electrode 40 responsible for a certain function and the surrounding electrodes 40 is maintained before and after the replacement is the same as in the first embodiment.

[0117] That is, focusing on the second primary drive electrode PD, before the replacement, on the tip side in the direction of the current of the second primary drive electrode PD, there is a second secondary drive electrode SD through which a current flows in the opposite direction, and on the base end side in the direction of the current of the second primary drive electrode PD, there is a second secondary detection electrode SPO through which a current flows in the opposite direction. Also, after the replacement, the second primary drive electrode PD is switched to a position rotated 45 degrees clockwise, and the direction of the current is reversed before and after the replacement. Also, even after the replacement, on the tip side in the direction of the current of the second primary drive electrode PD, there is a second secondary drive electrode SD through which a current flows in the opposite direction, and on the base end side in the direction of the current of the second primary drive electrode PD, there is a second secondary detection electrode SPO through which a current flows in the opposite direction.

[0118] Around the second primary drive electrode PD, electrodes 40 (the second secondary drive electrode SD, the second secondary detection electrode SPO) with the same potential exist before and after the replacement. Therefore, the potential difference between the second primary drive electrode PD and the surrounding electrodes 40 is the same before and after the replacement. At this time, the second primary drive electrode PD satisfies the conditions including that the position and function of the surrounding electrodes 40 are the same, the position and current direction of the surrounding electrodes 40 are the same, and the electrical connection order for each function of the surrounding electrodes 40 are the same, based on the position and current direction of the electrode 40 (the second primary drive electrode PD) that is the object of replacement before and after the replacement.

[0119] Although the electrodes 40 (the second secondary drive electrode SD, the second secondary detection electrode SPO) at positions close to the second primary drive electrode PD have been described, the second primary drive electrode PD also satisfies the above conditions for electrodes 40 other than the electrodes 40 at close positions.

[0120] Also, although the second primary drive electrode PD has been described, the other primary drive electrodes PD, secondary drive electrodes SD, primary detection electrodes PPO, and secondary detection electrodes SPO also satisfy the above conditions. Therefore, in any of the two primary drive electrodes PD, two secondary drive electrodes SD, two primary detection electrodes PPO, and two secondary detection electrodes SPO, the potential difference from the surrounding electrodes 40 is the same before and after the replacement.

[0121] Also, in the second embodiment, the positions of the electrodes 40 on the surface of the vibrator 20 among the primary drive electrode PD, the primary detection electrode PPO, the secondary detection electrode SPO, and the secondary drive electrode SD, the current direction of the electrodes 40, and the electrical connection order for each function of the electrodes 40 are set to be line-symmetric with respect to the virtual symmetry axis As to the positions, current directions, and electrical connection orders for each function of the electrodes 40 on the surface of the vibrator 20 that are set as the objects to be replaced with each other.

[0122] For example, focus on the second primary drive electrode PD. The position that is line-symmetric with respect to the virtual symmetry axis As of the second primary drive electrode PD before the replacement becomes a position rotated 45 degrees clockwise, which is the angle for detecting / canceling the secondary vibration. Therefore, the secondary drive electrode SD or the secondary detection electrode SPO must be arranged at this position. In the second embodiment, the secondary drive electrode SD is arranged at this position. Also, at this position, the direction of the current is reversed (line-symmetric), and the order of connection for each function is set to be the same (line-symmetric). The positions on the surface of the vibrator 20 between the electrodes 40b and 40c, which are set as the replacement partners, are line-symmetric with respect to the virtual symmetry axis As. Also, the direction of the current flowing through the electrode 40b and the direction of the current flowing through the electrode 40c face opposite directions, and the direction of the current is line-symmetric with respect to the virtual symmetry axis As. Further, the electrical connection order of both the electrode 40b and the electrode 40c is the same at number 2, and it can be said that the electrical connection order is line-symmetric with respect to the virtual symmetry axis As. Note that the same applies to the other primary drive electrodes PD, secondary drive electrodes SD, primary detection electrodes PPO, and secondary detection electrodes SPO other than the second primary drive electrode PD.

[0123] Also, the current inflow points P11 to P14 and the current outflow points P21 to P24 are also line-symmetric with respect to the virtual symmetry axis As before and after the replacement.

[0124] For example, the inflow point P11, which is the current inflow point to the current path by the two primary drive electrodes PD before the replacement, and the inflow point P12, which is the current inflow point to the current path by the two primary drive electrodes PD after the replacement, are line-symmetric with respect to the virtual symmetry axis As. That is, the inflow point P12, which is the current inflow point to the current path by the two secondary drive electrodes SD before the replacement, and the inflow point P11, which is the current inflow point to the current path by the two secondary drive electrodes SD after the replacement, are line-symmetric with respect to the virtual symmetry axis As. The same also applies to the inflow points P13 and 14 (and also to the primary detection electrode PPO and the secondary detection electrode SPO).

[0125] Also, for example, the outflow point P21, which is the outflow point of current to the current path by the two primary drive electrodes PD before the replacement, and the outflow point P22, which is the outflow point of current to the current path by the two primary drive electrodes PD after the replacement, are line-symmetric with respect to the virtual symmetry axis As. That is, the outflow point P22, which is the outflow point of current to the current path by the two secondary drive electrodes SD before the replacement, and the outflow point P21, which is the outflow point of current to the current path by the two secondary drive electrodes SD after the replacement, are line-symmetric with respect to the virtual symmetry axis As. Also, the same applies to the outflow points P23 and 24 (and also to the primary detection electrode PPO and the secondary detection electrode SPO).

[0126] Also, the inflow points P11 to P14 are also the inflow point P11 of current to the current path by the electrodes 40b and 40f, the inflow point P12 of current to the current path by the electrodes 40c and 40g, the inflow point P13 of current to the current path by the electrodes 40a and 40e, and the inflow point P14 of current to the current path by the electrodes 40d and 40h. The inflow points P11 and P14, and the inflow points P12 and P13 are line-symmetric with respect to the virtual symmetry axis As.

[0127] Also, the outflow points P21 to P24 are also the outflow point P21 of current from the current path by the electrodes 40b and 40f, the outflow point P22 of current from the current path by the electrodes 40c and 40g, the outflow point P23 of current from the current path by the electrodes 40a and 40e, and the outflow point P24 of current from the current path by the electrodes 40d and 40h. The outflow points P22 and P23, and the outflow points P21 and P24 are line-symmetric with respect to the virtual symmetry axis As.

[0128] The virtual symmetry axis As is an axis that passes through the center of the vibrator 20 and the center between the electrodes 40 and extends in the radial direction. In FIGS. 14 and 15, the virtual symmetry axis As passes through the center of the vibrator 20 and the center between the primary drive electrode PD and the secondary drive electrode SD that are swapped with each other during the replacement and extends in the radial direction. Also, the virtual symmetry axis As passes through the center of the vibrator 20, the center between the electrodes 40b and 40c, and the center between the electrodes 40f and 40g and extends in the radial direction.

[0129] In addition, other configurations of the second embodiment are the same as those of the first embodiment described above.

[0130] (Effect of the Second Embodiment) In the second embodiment, the following effects can be obtained.

[0131] In the vibration type gyro element 200 of the second embodiment, as described above, the primary drive electrode PD, the primary detection electrode PPO, the secondary detection electrode SPO, and the secondary drive electrode SD are electrically connected so that the potential difference from the surrounding electrodes 40 is maintained based on the position and current direction of the electrode 40 to be swapped before and after the swapping. Thus, similar to the first embodiment, in the configuration where swapping is performed, the influence (bias component) of the magnetic field due to the displacement current can be sufficiently canceled.

[0132] In addition, other effects of the second embodiment are the same as those of the first embodiment described above.

[0133] [Modification Example] It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is shown by the claims rather than the description of the above embodiments, and further includes all changes (modification examples) within the meaning and scope equivalent to the claims.

[0134] For example, the order of electrical connection of the electrodes and the virtual symmetry axis shown in the first and second embodiments above are merely examples and are not limited thereto.

[0135] For example, in the first modification of the first embodiment shown in FIGS. 16 and 17, the electrodes 40b, 40d, 40f, 40h are electrically connected in series in this order, and current flows in this order. Also, the electrodes 40a, 40g, 40e, 40c are electrically connected in series in this order, and current flows in this order. Also, the electrodes 40l, 40n, 40p, 40j are electrically connected in series in this order, and current flows in this order. Also, the electrodes 40o, 40m, 40k, 40i are electrically connected in series in this order, and current flows in this order. Further, when comparing electrodes 40 having the same potential and the same function before and after the interchange, based on the direction of the current in the electrode 40, the functions of the surrounding electrodes 40, the direction of the current, and the connection order for each function are the same. Also, the virtual symmetry axis As passes through the center of the vibrator 20, the center between the electrodes 40a and 40b (between the electrodes 40i and 40j), and the center between the electrodes 40e and 40f (between the electrodes 40m and 40n), and extends in the radial direction. Note that also in the first modification of the first embodiment, since the above conditions are satisfied, the influence due to the magnetic field from the displacement current can be sufficiently canceled, and with respect to the virtual symmetry axis As, the directions of the currents of the electrodes 40 to be interchanged and the connection order for each function are line-symmetric. Therefore, a structure that makes the potential difference between the electrodes 40 equal before and after the interchange can be realized with a simple structure.

[0136] Also, for example, in the second modification of the first embodiment shown in FIGS. 18 and 19, the electrodes 40b, 40d, 40f, 40h are electrically connected in series in this order, and current flows in this order. Also, the electrodes 40c, 40a, 40g, 40e are electrically connected in series in this order, and current flows in this order. Also, the electrodes 40l, 40n, 40p, 40j are electrically connected in series in this order, and current flows in this order. Also, the electrodes 40i, 40o, 40m, 40k are electrically connected in series in this order, and current flows in this order. Also, when comparing the electrodes 40 of the same potential with the same function before and after the exchange, based on the direction of the current in the electrode 40, the functions of the surrounding electrodes 40, the direction of the current, and the connection order for each function are the same. Also, the virtual symmetry axis As passes through the center of the vibrator 20, the center between the electrodes 40b and 40c (between the electrodes 40j and 40k), and the center between the electrodes 40f and 40g (between the electrodes 40n and 40o), and extends in the radial direction. Note that also in the second modification of the first embodiment, since the above conditions are satisfied, the influence of the magnetic field due to the displacement current can be sufficiently canceled, and with respect to the virtual symmetry axis As, the directions of the currents of the electrodes 40 to be exchanged and the connection order for each function are line-symmetric, so a structure that makes the potential difference between the electrodes 40 equal before and after the exchange can be realized with a simple structure.

[0137] Also, for example, in the third modification of the first embodiment shown in FIGS. 20 and 21, there are two primary detection electrodes PPO and two secondary detection electrodes SPO, which are arranged in a staggered manner. Also in this case, if the above conditions are satisfied, the influence of the magnetic field due to the displacement current can be sufficiently canceled. Note that in the third modification of the first embodiment, the primary detection electrodes PPO and the secondary detection electrodes SPO are arranged in a staggered manner, but the primary drive electrodes PD and the secondary drive electrodes SD, and the primary detection electrodes PPO and the secondary detection electrodes SPO may be arranged in a staggered manner. Also, the positions where the electrode 40 becomes staggered are not limited to the examples shown in FIGS. 20 and 21, but when providing the virtual symmetry axis As, the positions where the electrode 40 becomes staggered are also positions that are line-symmetric with respect to the virtual symmetry axis As.

[0138] In the third modification of the first embodiment, the electrodes 40b, 40d, 40f, and 40h are electrically connected in series in this order, and current flows in this order. Also, the electrodes 40c, 40a, 40g, and 40e are electrically connected in series in this order, and current flows in this order. Also, the electrodes 40l and 40n are electrically connected in series in this order, and current flows in this order. Also, the electrodes 40i and 40o are electrically connected in series in this order, and current flows in this order. Further, when comparing electrodes 40 having the same potential and the same function before and after the replacement, based on the direction of the current in the electrode 40, the functions of the surrounding electrodes 40, the direction of the current, and the connection order for each function are the same. Also, the virtual symmetry axis As passes through the center of the vibrator 20, the center between the electrodes 40b and 40c, and the center between the electrodes 40f and 40g (between the electrodes 40n and 40o), and extends in the radial direction. Note that also in the third modification of the first embodiment, since the above conditions are satisfied, the influence of the magnetic field due to the displacement current can be sufficiently canceled, and with respect to the virtual symmetry axis As, the directions of the currents of the electrodes 40 to be replaced and the connection order for each function are line-symmetric. Therefore, a structure that makes the potential difference between the electrodes 40 equal before and after the replacement can be realized with a simple structure.

[0139] Further, for example, in the first modification of the second embodiment shown in FIGS. 22 and 23, the electrodes 40b and 40f are electrically connected in series in this order, and current flows in this order. Also, the electrodes 40g and 40c are electrically connected in series in this order, and current flows in this order. Also, the electrodes 40h and 40d are electrically connected in series in this order, and current flows in this order. Also, the electrodes 40a and 40e are electrically connected in series in this order, and current flows in this order. Further, when comparing electrodes 40 having the same potential and the same function before and after the replacement, based on the direction of the current in the electrode 40, the functions of the surrounding electrodes 40, the direction of the current, and the connection order for each function are the same. Also, the virtual symmetry axis As passes through the center of the vibrator 20, the center between the electrodes 40a and 40h, and the center between the electrodes 40d and 40e, and extends in the radial direction. Note that also in the first modification of the second embodiment, since the above conditions are satisfied, the influence of the magnetic field due to the displacement current can be sufficiently canceled, and with respect to the virtual symmetry axis As, the directions of the currents of the electrodes 40 to be replaced and the connection order for each function are line-symmetric. Therefore, a structure that makes the potential difference between the electrodes 40 equal before and after the replacement can be realized with a simple structure.

[0140] In addition, in the above-described first embodiment, the first to third modification examples of the first embodiment, the second embodiment, and the first modification example of the second embodiment, an example in which a virtual symmetry axis is provided has been shown, but the present invention is not limited thereto. For example, in the second modification example of the second embodiment shown in FIGS. 24 and 25, although the virtual symmetry axis As is not provided, the above conditions are satisfied. For example, focusing on the second primary drive electrode PD, before the replacement, on the tip side in the direction of the current of the second primary drive electrode PD, there is a second secondary drive electrode SD through which a current in the same direction flows, and on the base end side in the direction of the current of the second primary drive electrode PD, there is a first secondary detection electrode SPO through which a current in the same direction flows. Also, even after the replacement, on the tip side in the direction of the current of the second primary drive electrode PD, there is a second secondary drive electrode SD through which a current in the same direction flows, and on the base end side in the direction of the current of the second primary drive electrode PD, there is a first secondary detection electrode SPO through which a current in the same direction flows. Therefore, the second primary drive electrode PD satisfies the above conditions. Also, although the second primary drive electrode PD has been described, the other primary drive electrodes PD, secondary drive electrodes SD, primary detection electrodes PPO, and secondary detection electrodes SPO also satisfy the above conditions.

[0141] In the second modification example of the second embodiment, before and after the replacement, the current inflow point, the current outflow point, the current direction, and the electrical connection order of the electrodes 40 are changed, whereby the above conditions are satisfied. Such a change can be realized by providing a structure such as a switch.

[0142] In the second modification of the second embodiment, the current inflow points P11a to P14a before the replacement are changed to the current inflow points P11b to P14b after the replacement. Similarly, the current outflow points P21a to P24a before the replacement are changed to the current inflow points P21b to P24b after the replacement. Also, before the replacement, the direction of the current in the electrodes 40a to 40h was clockwise, but after the replacement, the direction of the current in the electrodes 40a to 40h is changed to counterclockwise. Before the replacement, the electrodes 40b and 40f are electrically connected in series in this order, the electrodes 40c and 40g are electrically connected in series in this order, the electrodes 40d and 40h are electrically connected in series in this order, and the electrodes 40e and 40a are electrically connected in series in this order. On the other hand, after the replacement, the electrical connection order is changed so that the electrodes 40h and 40d are electrically connected in series in this order, and the electrodes 40a and 40e are electrically connected in series in this order. In the second modification of the second embodiment, by making such a change in the current path, the above conditions are satisfied. Thereby, also in the second modification of the second embodiment, the influence by the magnetic field derived from the displacement current can be sufficiently canceled.

[0143] Note that in the configuration of the first embodiment, the above conditions may be satisfied by changing the current inflow point, the current outflow point, the direction of the current, and the electrical connection order of the electrodes.

[0144] In the first and second embodiments, an example in which the primary vibration of the cos2θ mode is excited in the vibrator has been shown, but the present invention is not limited to this. For example, the primary vibration of the cosNθ (N is a natural number of 3 or more) mode may be excited in the vibrator. In this case, the support portion and the electrodes are provided at 4N azimuths arranged at equal angular intervals in the circumferential direction of the vibrator.

[0145] In addition, in the first and second embodiments described above, an example in which the vibrator is annular has been shown, but the present invention is not limited to this. For example, the vibrator may be ring-shaped such as a regular polygon. Also, the vibrator may be disk-shaped, hemispherical, or the like. When the vibrator is hemispherical, the electrodes on the vibrator are arranged on the curved surface of the hemisphere or the plane of the bottom surface.

[0146] Also, the shape of the support portion shown in the first and second embodiments above is merely an example and is not limited to this.

[0147] In addition, in the first and second embodiments described above, an example in which the primary drive electrode is interchanged with the secondary drive electrode and the primary detection electrode is interchanged with the secondary detection electrode has been shown, but the present invention is not limited to this. For example, the primary drive electrode may be interchanged with the secondary detection electrode and the primary detection electrode may be interchanged with the secondary drive electrode. When providing a virtual symmetry axis, the virtual symmetry axis may be provided so as to pass through the center between the electrodes to be interchanged (between the primary drive electrode and the secondary detection electrode, or between the primary detection electrode and the secondary drive electrode).

[0148] In addition, in the first embodiment described above, an example in which the primary drive electrode, the primary detection electrode, the secondary detection electrode, and the secondary drive electrode are each electrically connected in a clockwise order or a counterclockwise order for each function has been shown, but the present invention is not limited to this. For example, if the electrical connection of the four primary drive electrodes is in the order of 4→2→1→3 clockwise in the spatial arrangement, the primary drive electrode, the primary detection electrode, the secondary detection electrode, and the secondary drive electrode may each be electrically connected in an order other than the clockwise order or the counterclockwise order for each function. Also, an example in which all the electrodes are connected in series for each function has been shown, but a part of the electrodes connected for each function may be connected in parallel. Also, some of the electrodes may not be connected to other electrodes of the same function and may be independent.

[0149] In the first embodiment, an example in which reverse currents flow through two electrodes arranged in parallel with each other was shown, but the present invention is not limited to this. For example, currents in the same direction may flow through two electrodes arranged in parallel with each other.

[0150] In the first embodiment, an example in which two electrodes arranged in parallel with each other are provided on the support portion and the vibrator was shown, but the present invention is not limited to this. For example, three or more electrodes arranged in parallel with each other may be provided on the support portion and the vibrator. That is, the number of rows of electrodes may be three or more. Further, dummy ones in which no electrodes are arranged on the support portion may be included.

[0151] Also, the shape of the fixing portion shown in the first and second embodiments is merely an example and is not limited thereto. The shape of the fixing portion is not limited to a square, and the center of the fixing portion and the center of the vibrator do not have to coincide. Further, the angles of the support portion, the fixing portion, and the electrodes on the vibrator with respect to the center of the vibrator are not limited.

Explanation of Reference Numerals

[0152] 10 Fixing portion 20 Vibrator 30 Support portion 40, 40a to 40p Electrodes 60 Magnetic field application portion 100, 200 Vibration type gyro element 101 Gyroscope 150 Calculation unit As Virtual symmetry axis PD Primary drive electrode SD Secondary drive electrode PPO Primary detection electrode SPO Secondary detection electrode

Claims

1. A vibration type gyro element driven by electromagnetic force, comprising: a fixed part; a vibrator; a support part that connects the vibrator and the fixed part and supports the vibrator so as to be vibratable; a plurality of electrodes arranged in a row at intervals in the circumferential direction of the vibrator on the surface of the vibrator; a magnetic field applying part that applies a magnetic field to the electrodes; the vibrator has a vibration mode of cosNθ (N is a natural number of 2 or more); the electrodes include: a primary drive electrode that excites a primary vibration of the vibrator; a primary detection electrode that detects the primary vibration; a secondary detection electrode that detects a secondary vibration of the vibrator; a secondary drive electrode that drives the vibrator so as to cancel the secondary vibration; and are configured such that the primary drive electrode can be interchanged with either the secondary drive electrode or the secondary detection electrode, and the primary detection electrode can be interchanged with the other of the secondary detection electrode or the secondary drive electrode, and the electrical connection is set so that the potential difference between the electrodes in the periphery is maintained based on the position and current direction of the electrodes to be interchanged before and after the interchange. A vibration type gyro element.

2. The electrical connection is set so as to satisfy conditions including that the positions and functions of the electrodes in the periphery are the same, the positions and current directions of the electrodes in the periphery are the same, and the order of electrical connection for each function of the electrodes in the periphery is the same, based on the position and current direction of the electrodes to be interchanged before and after the interchange. The vibration type gyro element according to Claim 1.

3. The positions of the electrodes on the surface of the vibrator of the primary drive electrode, the primary detection electrode, the secondary detection electrode, and the secondary drive electrode, the current directions of the electrodes, and the order of electrical connection for each function of the electrodes are: set to be line-symmetric with respect to a virtual symmetry axis passing through the center of the vibrator and extending in the radial direction of the vibrator, the positions, current directions, and order of electrical connection for each function of the electrodes on the surface of the vibrator that are set as the objects to be interchanged. The vibration type gyro element according to Claim 2.

4. ​ The vibration type gyro element according to claim 3, wherein a plurality of the electrodes in a plurality of rows are arranged in parallel on the surface of the vibrator at intervals in the circumferential direction of the vibrator.

5. The primary drive electrodes are alternately arranged in the same row as either one of the secondary detection electrodes or the secondary drive electrodes. The vibration type gyro element according to claim 4, wherein the primary detection electrodes are alternately arranged in the same row as the other of the secondary detection electrodes or the secondary drive electrodes.

6. The primary drive electrodes, the primary detection electrodes, the secondary detection electrodes, and the secondary drive electrodes The vibration type gyro element according to claim 1, wherein they are electrically connected in the clockwise order or the counterclockwise order for each function.

7. A vibration type gyro element by electromagnetic drive, and an arithmetic unit that calculates an angular velocity based on an output signal from the vibration type gyro element. The vibration type gyro element includes a fixing part, a vibrator, a support part that connects the vibrator and the fixing part and supports the vibrator so as to be vibratable, a plurality of electrodes arranged in rows at intervals in the circumferential direction of the vibrator on the surface of the vibrator, and a magnetic field applying part that applies a magnetic field to the electrodes. The vibrator has a vibration mode of cosNθ (N is a natural number of 2 or more). The electrodes include a primary drive electrode that excites a primary vibration in the vibrator, a primary detection electrode that detects the primary vibration, a secondary detection electrode that detects a secondary vibration of the vibrator, and a secondary drive electrode that drives the vibrator so as to cancel the secondary vibration. The primary drive electrode is configured to be interchangeable with either one of the secondary drive electrode or the secondary detection electrode, and the primary detection electrode is configured to be interchangeable with the other of the secondary detection electrode or the secondary drive electrode. The primary drive electrodes, the primary detection electrodes, the secondary detection electrodes, and the secondary drive electrodes are electrically connected so that the potential difference from the surrounding electrodes is maintained based on the position and current direction of the electrodes to be interchanged before and after the interchange. The gyroscope.

Images