JP2010008300A - Inertia sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor for simultaneously detecting a yaw rate and acceleration in two axes within a substrate surface. <P>SOLUTION: The inertia sensor has an inertia sensor structure, having four in-plane vibrators in the same shape and ring beams in a structure being symmetrical with respect to a point for connecting the four in-plane vibrators that are arranged while being symmetrical with respect to a point. Concretely speaking, the inertia sensor has: the in-plane vibrators that are disposed on the extension line of two orthogonal axes at the same distance from a rotation center with the intersection of two orthogonal axes as a rotation center and supported movably in a direction parallel to a substrate surface, and have the same structure; and a link beam that mutually connects the vibrators movably in the directions of the two axes without any rotation in parallel with the substrate, has a structure that is symmetrical in respect to the rotation center, and is disposed in a region including the rotation center in a region for connecting the positions of the vibrators. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention uses a vibrating body formed on a substrate to detect an angular velocity (yaw rate) applied around an axis in the thickness direction of the substrate and a biaxial acceleration applied in an in-plane direction of the substrate. It is related with the inertial sensor for.

  Patent Document 1 discloses a triaxial angular velocity sensor that can detect angular velocities around the x, y, and z axes, respectively. Patent Document 1 shows an integrated structure in which a vibrating body is installed at a position located on each side of a polygon, and each vibrating body is connected by a beam.

  The vibrating bodies connected by the beams are supported only by the post disposed at the center and are in a state of floating from the substrate. The detecting means for detecting the angular velocity applied around the axis (z-axis) in the thickness direction of the substrate is located at the center of the coupled vibrating body, and the coupled vibrating bodies are displaced by the Coriolis force corresponding to the applied angular velocity. It is detected as a change in capacity associated with the rotational displacement of.

  Patent Document 2 discloses an angular velocity sensor structure using a vibrating body in order to detect angular velocities applied around two axes in the substrate surface. In this known example, in order to easily detect the Coriolis force generated by the applied angular velocity, the vibrating bodies are connected by a flexible spring. An integrated structure is disclosed. In this structure, the displacement corresponding to the Coriolis force is electrically detected as a capacitance change by the detection electrode formed at the lower part of the vibrating body.

Japanese Patent Laid-Open No. 11-064002 JP 07-218268 A

  The angular velocity sensor structure described in Patent Literature 1 and Patent Literature 2 enables detection of angular velocity applied around a plurality of axes, for example, around two axes in the substrate surface. However, since an angular velocity (yaw rate) applied around the substrate in the thickness direction of the substrate and a biaxial acceleration applied in the plane of the substrate are detected, there is no description regarding the sensor structure and means.

  Further, the sensor disclosed in Patent Document 1 is a state in which each diaphragm is connected by a beam, supported only by an anchor located at the center of the sensor, and floated in a hollow state. This sensor structure is a support structure lacking in stability. Low resistance to impact force from outside the sensor. There is a high possibility that the diaphragm comes into contact with and adheres to the substrate supporting it due to an external impact force. Further, when the impact force is large, there is a possibility that the diaphragm collides with the substrate supporting the vibrating body, and the diaphragm is broken.

  An object of the present invention is to provide a single-structure inertial sensor that can simultaneously detect an angular velocity (yaw rate) applied around an axis in the thickness direction of a substrate and an acceleration applied to two axes in the plane of the substrate. Is to provide.

  The second object is to provide an inertial sensor that is not fixed to a supporting substrate and is strong against the impact of disturbance, that is, has high impact resistance.

  In order to achieve the above object, the solving means in the present invention is as follows.

  The first means is arranged on the extension line of the orthogonal two axes at the same distance from the rotation center with the intersection of the orthogonal two axes as the rotation center, and is supported in a movable state in the in-plane direction of the substrate. The in-plane vibrating body having a structure and the vibrating bodies are connected to each other so as to be movable in the direction of the two axes without rotating in the in-plane direction of the substrate, and have a point-symmetric structure about the rotation center. And an inertial sensor including a link beam arranged in a region connecting the positions of the vibrating bodies and in a region including the rotation center.

  The second means is the inertial sensor described as the first means, wherein the vibrating body is a first two-degree-of-freedom vibration mass movable in the direction of the two orthogonal axes and one direction of the two orthogonal axes. The second and third drive masses with one degree of freedom including the driving means supported on the substrate so as to be movable only on the substrate, and supported on the substrate so as to be movable only in the other direction of the two orthogonal axes. A fourth and fifth one-degree-of-freedom detection mass including detection means, and a beam connecting the vibration mass, the drive mass, and the detection mass, and the second and third drive masses are The fourth and fifth detection masses are placed in line-symmetrical positions with respect to the second axis, and the first axis and the second axis are placed in line-symmetrical positions with respect to the first axis. Is composed of the in-plane vibrating body, which is configured to have the vibration mass arranged in a region perpendicular to each other and including the orthogonal point. Good be configured.

  Further, in the inertial sensor described in the second means, the inertial sensor is provided on the surface of the vibration mass, the drive mass, and the detection mass, and is provided with a protrusion structure on the surface facing the substrate that supports each mass. A sensor is preferable.

  Furthermore, in the inertial sensor described in the first and second means, the link beam may be an inertial sensor having a structure connected to the drive mass.

  According to the present invention, the angular velocity (yaw rate) applied around the substrate in the thickness direction of the substrate and the biaxial acceleration applied in the plane of the substrate can be detected simultaneously with a single sensor structure.

  Hereinafter, embodiments of the inertial sensor of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a conceptual diagram showing the concept of an inertial sensor disclosed in the present invention. FIG. 1 shows vibrating bodies 1a, 1b, 1c, and 1d that are sensor elements constituting an inertial sensor. Each of the vibrators has the same configuration and structure. The vibrating body 1a is vibrated in the in-plane direction by the springs 2a and 3a, the vibrating body 1b is vibrated by the springs 2b and 3b, the vibrating body 1c is vibrated by the springs 2c and 3c, and the vibrating body 1d is vibrated by the springs 2d and 3d. Supported as possible. The vibrating bodies 1a, 1b, 1c, and 1d include a driving unit (not shown) that generates vibration, a detecting unit that detects displacement due to Coriolis force generated in proportion to the applied angular velocity, or displacement due to applied acceleration ( (Not shown) are respectively formed. The springs 3a, 3b, 3c, and 3d are connected to the anchor portion 4 serving as a fixed portion. As shown by arrows in FIG. 1, the vibrating body 1a and the vibrating body 1b can vibrate in the x-axis direction, and the vibrating body 1c The vibrating body 1d can vibrate in the y-axis direction. The connection point 5 of the springs 2a, 2b, 2c and 2d is not a fixed point. As shown in FIG. 1, the vibration directions of the vibrating bodies 1a and 1b and the vibration directions of the vibrating bodies 1c and 1d are orthogonal to each other. The driving means for generating vibration may have a structure for generating an electrostatic attractive force using a comb electrode, a structure using a piezoelectric strain force, or a structure using a Lorentz force using an electromagnetic field.

  Specific driving modes of the vibrators 1a, 1b, 1c, and 1d are as follows. As a premise, the vibrating bodies 1a and 1b are components constituting a tuning fork vibrating body that vibrates with each other. The vibrating bodies 1c and 1d are constituent elements that constitute a tuning fork vibrating body that vibrates with each other. The tuning fork vibrating body composed of the vibrating bodies 1a and 1b and the tuning fork vibrating body composed of the vibrating bodies 1c and 1d are inverted in phase, that is, shifted by 180 degrees. Specifically, when the vibrating body 1a moves in the negative x-axis direction and the vibrating body 1b moves in the positive x-axis direction, the vibrating body 1c moves in the negative y-axis direction and the vibrating body 1d moves in the positive y-axis direction. Work towards. Conversely, when the vibrating body 1a moves in the positive x-axis direction and the vibrating body 1b moves in the negative x-axis direction, the vibrating body 1c moves in the positive y-axis direction and the vibrating body 1d moves in the negative y-axis direction. Operate. In order to realize such vibration, the driving means applies a force to each vibrating body. Note that the driving means desirably causes the vibrating bodies 1a, 1b, 1c, and 1d to resonate and vibrate. In this case, the vibration amplitude, that is, the vibration speed is maximized, and the displacement due to the Coriolis force proportional to the angular velocity can be maximized.

  At this time, if there is an individual difference in shape due to a processing error in each vibrator, the resonance frequencies of the vibrators do not exactly match. However, since the connection point 5 is connected to the four springs 2a, 2b, 2c, 2d, the vibrations of the vibrating bodies interfere with each other. As a result, the vibrations of the vibrators vibrate synchronously. That is, since there are unconstrained connection points 5, vibration errors due to such individual differences can be absorbed. The inertial sensor shown in FIG. 1 has this feature.

In the vibrating body 1a, the resonance frequency in the x-axis direction is ω _x , and the resonance frequency in the y-axis direction is ω _y . The x-axis direction is the vibration direction of the vibrating body, and the y-axis direction is a detection direction for detecting displacement due to acceleration and displacement due to Coriolis force proportional to the angular velocity. That is, the detection direction is a direction orthogonal to the vibration direction with respect to the vibration direction. At this time, the resonance frequency ω _x in the vibration direction is preferably smaller than the resonance frequency ω _{y in the} detection direction. Although the vibration body 1a has been described as a representative, the same can be said for the other vibration bodies 1b, 1c, and 1d.

  Next, FIG. 2 is a conceptual diagram showing a case where the springs 2a, 2b, 2c, 2d, 3a, 3b, 3c, and 3d shown in FIG. 1 are replaced with a beam structure. Specifically, the spring 3 a can be replaced with the beam 6, and the springs 2 a, 2 b, 2 c, 2 d including the connection point 5 can be replaced with the link beam 7. The springs 3b, 3c, and 3d can be replaced as beams attached to the vibrating bodies 1b, 1c, and 1d, respectively, similarly to the spring 6 attached to the vibrating body 1a.

  The link beam 7 has a point-symmetric structure in which the vibrating bodies 1a, 1b, 1c, and 1d are connected. The point symmetry center of the link beam 7 is located in the range connecting the vibrating bodies 1a, 1b, 1c, 1d. By forming the link beam 7 at this position, the concept of the inertial sensor shown in FIG. 1 can be satisfied.

  The link beam 7 may have a point-symmetric structure in which the vibrating bodies 1a, 1b, 1c, and 1d are connected. In addition to the structure of the link beam 7 shown in FIG. 2, for example, the shape of the link beam 7 of FIG. 3 and the shape of the link beam 7 of FIG. Any other structure may be used as long as it is a point-symmetric beam structure.

  Next, a specific structure of the vibrating bodies 1a, 1b, 1c, and 1d that enables in-plane vibration will be described. Here, as a representative example, the structure of the vibrator 1a shown in FIG. 5 will be described.

  The vibrating body 1a constituting the inertial sensor includes a driving mass 8a, 8b having one degree of freedom including driving means 11a, 11b, 12a, 12b that generate vibrations, and displacement due to Coriolis force generated in proportion to the applied angular velocity. Alternatively, it includes detection masses 9a and 9b with one degree of freedom and detection masses 10 with two degrees of freedom including detection means 15a and 15b for detecting displacement due to applied acceleration. The drive masses 8a and 8b operate only in the x-axis direction from the structure of the bending beams 13a and 13b and the positions where the anchor portions 14a and 14b are formed. One ends of the bending beams 13a and 13b are connected to the driving masses 8a and 8b. The other end is connected to the anchor portions 14a and 14b. On the other hand, the detection masses 9a and 9b operate only in the y-axis direction from the structure of the bending beams 16a and 16b and the positions where the anchor portions 17a and 17b are formed. Both detection masses 9a and 9b are connected and supported by four bending beams 16a and 16b. One ends of the bending beams 16a and 16b are connected to the anchor portions 17a and 17b. Bending beams 18a and 18b connected to the drive masses 8a and 8b are connected to the vibration mass 10. Further, straight beams connected to the detection masses 9a and 9b are connected. This beam configuration allows the vibration mass to move in the x-axis and y-axis directions.

  The vibration mass 10 is disposed so as to be surrounded by the drive masses 8a and 8b and the detection masses 9a and 9b. The drive masses 8a and 8b are arranged symmetrically with respect to the BB ′ axis, while the detection masses 9a and 9b are arranged symmetrically with respect to the AA ′ axis. These line symmetry axes are orthogonal to each other. A vibration mass 10 is formed in a region including the orthogonal point. Thus, the vibrating body 1a has a symmetrical structure.

  Next, FIG. 6 is a cross-sectional structure diagram showing an aa ′ cross section of the vibrating body 1a shown in FIG. The board | substrate 20 is a board | substrate (not shown) to which the anchor parts 14a, 14b, 17a, and 17b are connected. A protrusion 19 is formed on the lower surface of the vibration mass 10 as shown in FIG. The height of the protrusion is several hundred nanometers to several microns, and the width is about several microns to several tens of microns. In order to vibrate the vibrating body 1a in the in-plane direction, the gap between the substrate 20 and the vibrating body 1a (the vibrating mass 10 in FIG. 6) is about 1 to 4 μm. Here, the thickness of the vibration mass is 60 μm, and the thickness of the substrate 20 is 350 μm. Each thickness is an example.

  Here, when a disturbance is applied in the thickness direction of the substrate 20, the vibrating body 1 a supported in a freely vibrating state, in FIG. 6, the vibration mass 10 receives acceleration in the thickness direction of the substrate. When the acceleration is large, the vibration mass 10 contacts the substrate 20. When the protrusion 19 is on the vibration mass 10, the contact area is extremely small as compared to the case without the protrusion 19. Therefore, sticking (fixing) to the underlying substrate 20 can be easily avoided. This is because the smaller the contact area, the smaller the surface force and the harder it is to stick. The projection 19 plays a role of a stopper. Therefore, if the protrusion 19 is formed, it can be said that the vibrating body 1a has a high impact resistance and a structure protected from disturbance. Although not shown, the protrusion 19 is also formed on the drive masses 8a and 8b and the detection masses 9a and 9b.

  FIG. 7 shows the structure of an inertial sensor in which the vibrating body 1 a shown in FIG. 5 and other vibrating bodies 1 b, 1 c, 1 d are connected by a link beam 7. The shape of the link beam 7 is shown in FIG. As shown in the figure, the link beam 7 is connected to the drive mass (drive mass 8b in FIG. 5) of each vibrator, and is not connected to the detection mass or the vibration mass. The link beam 7 having this structure can oscillate the tuning fork in synchronization with each vibrating body even when there are individual differences in shape due to processing errors.

  FIG. 8 shows an inertial sensor having another structure in which the vibrating body 1a shown in FIG. 5 and the other vibrating bodies 1b, 1c, 1d are connected by the link beam 7 shown in FIG. As in the case of FIG. 7, the link beam 7 is connected to the drive mass (drive mass 8 b in FIG. 5) of each vibrator, and is not connected to the detection mass or the vibration mass. By connecting in this way, it is possible to synchronize the vibrations of the vibrating bodies 1a, 1b, 1c, and 1d that constitute the inertial sensor and to enable tuning fork vibration. That is, it is possible to synchronize the vibration of the driving mass of each vibrator.

  Next, a driving voltage application method for synchronously vibrating the vibrating bodies 1a, 1b, 1c, and 1d constituting the inertial sensor will be described using the case of the vibrating body 1a shown in FIG. The same applies to the other vibrators 1b, 1c, and 1d.

As shown in the figure, the signal generating circuit 21 outputs two signals, a first excitation signal V _dc + V ₀ sinωt and a second excitation signal V _dc −V ₀ sinωt. Here, V _dc is a DC bias voltage, V ₀ sinωt is an AC voltage, and its amplitude is V ₀ . Here, ω is given a frequency at which the vibrating body 1a can be driven at the resonance frequency. These two signals are connected to each driving means by electric wiring. Specifically, based on the numbers shown in FIG. 5, the first excitation signal is applied to the drive means 12a and 11b, and the second excitation signal is applied to the drive means 11a and 12b. The vibrating body 1a is connected to GND.

  In the following description using FIG. 9, the description will be made in comparison with the numbers shown in FIG.

  At this time, a voltage is applied as shown in the time chart of FIG. At time t1, since the voltage of the first vibration signal is higher than the voltage of the second vibration signal, a high electrostatic attraction is generated in the drive units 12a and 11b, and the vibrating body 1a operates in the positive direction of the x axis. On the other hand, at time t2, since the voltage of the second vibration signal is higher than the voltage of the first vibration signal, a high electrostatic attraction is generated in the drive units 11a and 11b, and the vibrating body 1a operates in the negative direction of the x axis. . Since the excitation signal is a sine wave, it vibrates in the x-axis direction at the frequency ω, that is, the resonance frequency of the vibrating body 1a. With the connection configuration as described above, the vibrating body 1a can be vibrated in the in-plane direction. The vibration generated here is transmitted to the other vibrating bodies 1b, 1c, 1d via the link beam 7.

  Next, a method for detecting a change in capacitance of the vibrating body 1a when an angular velocity Ω is applied around the z axis will be described. When the vibrating body 1a is constantly oscillating in the x-axis direction, a Coriolis force Fc is generated in the vibrating mass 10 when the angular velocity Ω is applied around the z-axis. This force is transmitted to the detection masses 9a and 9b through the straight beam. For example, when the generated Coriolis force Fc is applied in the positive y-axis direction as shown in FIG. 9, the detection means 15a reduces its capacity, and the detection means 15b increases its capacity. This can be understood by looking at the structure of the gaps of the comb teeth constituting the detection means 15a, 15b in FIG. That is, in the detection means 15a, the comb tooth gap is increased by the applied Coriolis force Fc, and in the detection means 15b, the comb tooth gap is reduced. Therefore, the capacity is reduced in the former, and the capacity is increased in the latter.

In this way, the capacitance change at each detection means generated by the Coriolis force Fc is subtracted by the subtraction / capacitance / voltage conversion circuit 22 to convert the capacitance-voltage (CV), and the capacitance change is regarded as a voltage change. , Take out the signal. At this time, assuming that the capacity of the initial detecting means is C ₀ , the initial gap is d ₀ , the capacity change caused by the Coriolis force Fc is ΔC, and the displacement is Δd, ΔC = 2C ₀ ( The relational expression of Δd / d ₀ is established. In this way, the displacement amount due to the Coriolis force Fc can be detected by the capacitance-voltage conversion circuit 22 as the voltage change amount ΔV.

  Next, a method for driving the inertial sensor will be described using the inertial sensor described in FIG. 7 as an example.

In FIG. 10, the signal generating circuit 21 outputs two signals of a first excitation signal V _dc + V ₀ sinωt and a second excitation signal V _dc −V ₀ sinωt. The output terminal of the second excitation signal V _dc -V ₀ sinωt is (1), and the output terminal of the first excitation signal V _dc + V ₀ sinωt is (2). These output terminals are connected to each driving means in the figure, and each signal is applied. At this time, a voltage is applied as in the time chart shown in FIG. Here, at the time t1 in the figure, since the voltage of the first vibration signal is higher than the voltage of the second vibration signal, the vibration body 1a vibrates in the x-axis negative direction and the vibration body 1b vibrates in the x-axis positive direction. The body 1c operates in the y-axis negative direction, and the vibrating body 1d operates in the y-axis positive direction. On the other hand, at time t2, since the voltage of the second vibration signal is higher than the voltage of the first vibration signal, the vibrating body 1a is in the positive x-axis direction, the vibrating body 1b is in the negative x-axis direction, and the vibrating body 1c is y In the positive axis direction, the vibrating body 1d operates in the negative y-axis direction. Since the excitation signal is a sine wave, it vibrates in the x-axis direction or the y-axis direction at its frequency ω, that is, the resonance frequency of each vibrating body. With the connection configuration as described above, each vibrating body can be vibrated in the in-plane direction. Vibration due to the force generated by the driving means formed on each vibrating body is transmitted to other vibrating bodies via the link beam 7. Each vibration interferes with each other and tunes to form a single vibration. The link beam 7 is operated so as to push and pull the vibrating body in order to promote the vibration of each vibrating body. With the above configuration and voltage application method, the inertial sensor can be driven and vibrated via the link beam 7.

  Next, a method for detecting the angular velocity and acceleration of the inertial sensor will be described with reference to FIG. Since the driving method of the sensor has been described above, it is omitted here. The sensor is constantly oscillating in the x-axis or y-axis direction.

  As shown in FIG. 11, each detection means in the detection mass constituting each vibrating body is connected to each other, and their outputs are output (3) to (10). These outputs are input to the subtraction and capacitance / voltage conversion circuit 22 as shown in FIG. Thereafter, the converted voltage value is input to the differential amplifier circuit 24 or the addition amplifier circuit 25. Thereafter, the synchronous detection circuit 23 performs synchronous detection with the signal from the signal generation circuit 21, and a detection signal including a displacement component due to angular velocity and acceleration is obtained. Finally, the detection signal indicating the z-axis angular velocity Ω (yaw rate), the y-axis direction acceleration, and the x-axis direction acceleration can be obtained through the filter 26. Through the circuit block shown here, a single-structure inertial sensor can simultaneously detect z-axis angular velocity Ω (yaw rate) and x-axis and y-axis acceleration (in-plane acceleration) simultaneously. it can.

  According to the above description, the angular velocity (yaw rate) applied around the substrate in the thickness direction of the substrate and the biaxial acceleration applied in the plane of the substrate can be detected simultaneously with a single sensor structure. .

  In addition, even if there are variations in shape due to processing errors in the multiple in-plane vibrators that make up the sensor, a mechanical link beam with no fixed point is provided, so each vibrator is actively synchronized. Can be made.

  Furthermore, since the sensor vibrating body is provided with a projection structure that serves as a stopper, it is not fixed to the substrate that supports the protrusion even by an external impact. Even if the impact force from the outside is large, since there is a projection structure, it becomes a stopper, and the vibrating body is protected.

It is a conceptual diagram which shows the concept of the inertial sensor disclosed by this invention. It is the figure which replaced the concept of the inertial sensor disclosed by this invention with the beam structure. It is a conceptual structure figure of an inertial sensor provided with a link beam of another structure. It is a conceptual structure figure of an inertial sensor provided with a link beam of another structure. It is a figure which shows the specific structure of the vibrating body which enables an in-plane vibration. It is a cross-section figure which shows the aa 'cross section of a vibrating body. It is a structural diagram of an inertial sensor. FIG. 6 is a structural diagram of an inertial sensor having a different structure with a different link beam structure. It is a figure explaining the drive voltage application method and the method of detecting a capacity | capacitance change in order to vibrate the vibrating body which comprises an inertial sensor. It is a figure explaining the drive method of an inertial sensor. It is a figure explaining the angular velocity and acceleration detection method of an inertial sensor.

Explanation of symbols

1a, 1b, 1c, 1d Vibrators 2a, 2b, 2c, 2d, 3a, 3b, 3c, 3d Spring 4, 14a, 14b, 17a, 17b Anchor portion 5 Connection point 6 Beam 7 Link beam 8a, 8b Drive mass 9a , 9b Detection mass 10 Vibration mass 11a, 11b, 12a, 12b Drive means 13a, 13b, 16a, 16b, 18a, 18b Bending beam 15a, 15b Detection means 19 Protrusion 20 Substrate 21 Signal generation circuit 22 Subtraction and capacitance / voltage conversion Circuit 23 Synchronous detection circuit 24 Differential amplifier circuit 25 Summing amplifier circuit 26 Filter

Claims (4)

  An in-plane vibration having the same structure, which is arranged on the extension line of the orthogonal two axes at the same distance from the rotation center with the intersection of the orthogonal two axes as the rotation center, is supported in a movable state in the in-plane direction of the substrate. The vibrating bodies are connected to each other so as to be movable in the direction of the two axes without rotating in the in-plane direction of the substrate and the substrate, and has a point-symmetric structure with respect to the center of rotation. An inertial sensor comprising a link beam arranged in a region where the positions are connected and in a region including the rotation center.   The vibrator includes a first two-degree-of-freedom vibration mass movable in the direction of the two orthogonal axes, and a driving unit supported by the substrate so as to be movable only in one direction of the two orthogonal axes. Fourth and fifth one-degree-of-freedom detection masses including detection means supported by the substrate so as to be movable only in the other direction of the two orthogonal axes with the second and third driving masses with one degree of freedom. And a beam connecting the vibration mass, the drive mass, and the detection mass, and the second and third drive masses are placed in a line-symmetrical position with respect to the first axis, and the fourth The fifth detection mass is placed at a position symmetrical with respect to the second axis, the first axis and the second axis are orthogonal to each other, and the vibration mass is arranged in a region including the orthogonal point. The inertial sensor according to claim 1, comprising the in-plane vibrating body.   The inertial sensor according to claim 2, wherein a protrusion structure is provided on a surface of the vibration mass, the driving mass, and the detection mass and facing a substrate that supports each mass.   The inertial sensor according to claim 1, wherein the link beam has a structure connected to the drive mass.

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