阅读说明：本技术 惯性传感器以及惯性测量装置 (Inertial sensor and inertial measurement unit ) 是由 泷泽照夫 永田和幸 田中悟 山崎成二 于 2021-07-06 设计创作，主要内容包括：本发明涉及惯性传感器和惯性测量装置。惯性传感器中,能够绕沿着第一方向的第一旋转轴摆动的第一可动体具有开口部,在开口部具有：第二可动体,能够绕沿着第二方向的第二旋转轴摆动；第二支承梁,作为第二旋转轴来支承第二可动体(38)；第三可动体,能够绕沿着上述第二方向的第三旋转轴摆动；以及第三支承梁,作为上述第三旋转轴来支承上述第三可动体,具有突起,上述突起设置于与第二可动体以及第三可动体对置的面或者第二可动体(38)以及第三可动体,并朝向第二可动体以及第三可动体或者面突出。(The invention relates to an inertial sensor and an inertial measurement unit. In the inertial sensor, a first movable body that is swingable about a first rotation axis along a first direction has an opening, and the opening has: a second movable body swingable about a second rotation axis along a second direction; a second support beam that supports the second movable body (38) as a second rotation axis; a third movable body that is swingable about a third rotation axis along the second direction; and a third support beam that supports the third movable body as the third rotation axis, and has a protrusion that is provided on a surface facing the second movable body and the third movable body or on the second movable body (38) and the third movable body, and protrudes toward the second movable body and the third movable body or the surface.)

1. An inertial sensor, comprising:

a substrate;

a first movable body disposed on the base plate and capable of swinging about a first rotation axis along a first direction;

a first support beam that supports the first movable body as the first rotation shaft; and

a cover joined to the substrate and covering the first movable body and the first support beam,

the first movable body has an opening portion,

the opening portion has:

a second movable body swingable about a second rotation axis along a second direction intersecting the first direction;

a second support beam that connects the first movable body and the second movable body and supports the second movable body as the second rotation shaft;

a third movable body swingable about a third rotation axis along the second direction; and

a third support beam that connects the first movable body and the third movable body and supports the third movable body as the third rotation axis,

the inertial sensor includes a protrusion provided on a surface of the substrate or the cover or the second movable body and the third movable body facing the second movable body and the third movable body, the protrusion overlapping the second movable body and the third movable body in a plan view, and the protrusion protruding toward the second movable body and the third movable body or the surface.

2. An inertial sensor according to claim 1,

the second movable body and the third movable body are disposed line-symmetrically with a center line of the first movable body along the second direction as a symmetry axis,

the center of gravity of the second movable body is closer to the second support beam than the center line,

the center of gravity of the third movable body is closer to the third support beam than the center line.

3. An inertial sensor according to claim 2,

the second support beam coincides with the centerline-side end of the second movable body,

the third support beam coincides with an end portion on the centerline side of the third movable body.

4. An inertial sensor according to claim 2,

the end portion on the centerline side of the second movable body is closer to the centerline than the second support beam,

the end portion on the centerline side of the third movable body is closer to the centerline than the third support beam.

5. An inertial sensor according to any one of claims 1 to 4,

the torsional rigidity of the second support beam and the third support beam is higher than that of the first support beam.

6. An inertial sensor according to any one of claims 1 to 4,

a resonance frequency of the second movable body about the second rotation axis is 2 times or more a resonance frequency of the first movable body about the first rotation axis,

the resonance frequency of the third movable body about the third rotation axis is 2 times or more the resonance frequency of the first movable body about the first rotation axis.

7. An inertial sensor according to any one of claims 1 to 4,

the resonance frequency of the second movable body and the third movable body in the in-phase mode around the second rotation axis or around the third rotation axis is 2 times or more the resonance frequency of the first movable body around the first rotation axis.

8. An inertial sensor according to any one of claims 1 to 4,

the inertial sensor includes:

a first elastic section provided between one end of the first movable body in the first direction and the second movable body; and

and a second elastic section provided between the other end of the first movable body in the first direction and the third movable body.

9. An inertial sensor according to any one of claims 1 to 4,

the inertial sensor further includes a third elastic portion and a fourth elastic portion,

the third elastic portion and the fourth elastic portion are disposed between the first movable body and the second movable body and between the third movable body and the fourth movable body in the second direction.

10. An inertial sensor, comprising:

a substrate;

a first movable body disposed on the base plate and capable of swinging about a first rotation axis along a first direction;

a first support beam that supports the first movable body as the first rotation shaft; and

a cover joined to the substrate and covering the first movable body and the first support beam,

the first movable body has an opening portion,

the opening portion has:

a second movable body swingable about a second rotation axis along a second direction intersecting the first direction;

a second support beam that connects the first movable body and the second movable body and supports the second movable body as the second rotation shaft;

a third movable body swingable about a third rotation axis along the second direction; and

a third support beam that connects the first movable body and the third movable body and supports the third movable body as the third rotation axis,

the inertial sensor includes a protrusion provided on a surface of the substrate or the cover facing the second movable body and the third movable body, the protrusion overlapping the second movable body and the third movable body in a plan view, and the protrusion protruding toward the second movable body and the third movable body.

11. An inertial sensor, comprising:

a substrate;

a first movable body disposed on the base plate and capable of swinging about a first rotation axis along a first direction;

a first support beam that supports the first movable body as the first rotation shaft; and

a cover joined to the substrate and covering the first movable body and the first support beam,

the first movable body has an opening portion,

the opening portion has:

a second movable body swingable about a second rotation axis along a second direction intersecting the first direction;

a second support beam that connects the first movable body and the second movable body and supports the second movable body as the second rotation shaft;

a third movable body swingable about a third rotation axis along the second direction; and

a third support beam that connects the first movable body and the third movable body and supports the third movable body as the third rotation axis,

the inertial sensor includes a protrusion provided on the second movable body and the third movable body, the protrusion overlapping the second movable body and the third movable body in a plan view, and the protrusion protruding toward a surface of the substrate or the cover facing the second movable body and the third movable body.

12. An inertial measurement unit comprising:

an inertial sensor according to any one of claims 1 to 11; and

and a control unit that performs control based on a detection signal output from the inertial sensor.

Technical Field

The present invention relates to an inertial sensor and an inertial measurement unit.

Background

In recent years, inertial sensors manufactured using MEMS (Micro Electro Mechanical Systems) technology are being developed. As such an inertial sensor, for example, patent document 1 describes a physical quantity sensor including: a support substrate; a movable body which is arranged on the support substrate, has a first mass part and a second mass part, and performs seesaw type swing around a rotating shaft; and first and second fixed electrodes provided on the support substrate and facing the first and second mass portions, and capable of detecting acceleration in the vertical direction based on a change in capacitance between the first and second mass portions, which are different in torque of the movable body around the rotation axis, and the first and second fixed electrodes disposed at positions where the first and second mass portions face each other.

In this physical quantity sensor, in order to prevent the movable body from contacting the first and second fixed electrodes when the movable body is excessively seesawed, the support substrate is provided with projections projecting toward the first and second mass portions.

Patent document 1: japanese patent laid-open publication No. 2019-45172

However, when the physical quantity sensor described in patent document 1 receives strong vibration or impact from the outside, the movable body collides with the protrusion due to excessive seesaw-type rocking. Although it is possible to avoid the movable body from short-circuiting the first and second fixed electrodes due to collision with the protrusions, the movable body and the protrusions may be damaged if the impact cannot be absorbed. In other words, when the inertial sensor receives vibration or impact with a constant energy or more, the movable body may collide with the protrusion as a single rigid body, and the contact portion between the movable body and the protrusion may be broken. Further, when the movable body repeatedly collides with a constant energy as one rigid body, an operation failure may occur due to a sticking phenomenon called sticking.

Disclosure of Invention

An inertial sensor, comprising: a substrate; a first movable body disposed on the base plate and capable of swinging about a first rotation axis along a first direction; a first support beam that supports the first movable body as the first rotation shaft; and a cover that is joined to the substrate and covers the first movable body and the first support beam, wherein the first movable body has an opening, and the opening has: a second movable body swingable about a second rotation axis along a second direction intersecting the first direction; a second support beam that connects the first movable body and the second movable body and supports the second movable body as the second rotation shaft; a third movable body swingable about a third rotation axis along the second direction; and a third support beam that connects the first movable body and the third movable body and supports the third movable body as the third rotation axis, wherein the inertial sensor has a protrusion provided on a surface of the substrate or the cover facing the second movable body and the third movable body or on the second movable body and the third movable body, the protrusion overlapping the second movable body and the third movable body in a plan view, and the protrusion protruding toward the second movable body and the third movable body or the surface.

The inertia measurement device is provided with: the inertial sensor described above; and a control unit that performs control based on a detection signal output from the inertial sensor.

Drawings

Fig. 1 is a plan view showing a schematic structure of an inertial sensor according to a first embodiment.

Fig. 2 is a sectional view taken along line a-a of fig. 1.

Fig. 3 is a schematic diagram for explaining the operation of the inertial sensor.

Fig. 4 is a schematic diagram for explaining the operation of the inertial sensor.

Fig. 5 is a plan view showing a schematic structure of an inertial sensor according to a second embodiment.

Fig. 6 is a plan view showing a schematic structure of an inertial sensor according to a third embodiment.

Fig. 7 is a plan view showing a schematic structure of an inertial sensor according to a fourth embodiment.

Fig. 8 is an enlarged view of a portion B of fig. 7.

Fig. 9 is a plan view showing a schematic structure of an inertial sensor according to a fifth embodiment.

Fig. 10 is a cross-sectional view showing a schematic structure of an inertial sensor according to a sixth embodiment.

Fig. 11 is a cross-sectional view showing a schematic structure of an inertial sensor according to a seventh embodiment.

Fig. 12 is a cross-sectional view showing a schematic structure of an inertial sensor according to an eighth embodiment.

Fig. 13 is an exploded perspective view showing a schematic configuration of an inertia measurement apparatus including an inertia sensor according to a ninth embodiment.

Fig. 14 is a perspective view of the substrate of fig. 13.

Description of the reference numerals

1. 1a, 1b, 1c, 1d, 1e, 1f, 1g … inertial sensors; 2 … a substrate; 3 … sensor element; a 5 … cover; 7. 8 … sides; 21 … recess; 21a … recess; 22 … a fixed part; 23 … protrusions; 24 … a first detection electrode; 25 … a second detection electrode; 26 … dummy electrode; 27 … an insulating layer; 31 … first movable body; a 32 … holding portion; 33 … a first support beam; 34 … a first mass portion; 35 … a second mass portion; 36 … a third mass portion; 37 … second support beam; 38 … second movable body; 39 … third support beam; 40 … third movable body; 41 … a first connecting part; 42 … second joint; 43 … third joint; 44 … fourth joint; 45 … first opening part; 46 … a second opening; 47 … a third opening; 48 … a fourth opening; 51 … recess; 2000 … inertial measurement unit; ca. Cb … electrostatic capacitance; g1, G2 … center of gravity; j1 … first axis of rotation; j2 … second axis of rotation; j3 … third axis of rotation; the L … centerline; s … storage space; s1, S2 … acceleration.

Detailed Description

1. First embodiment

First, an acceleration sensor that detects acceleration in the vertical direction will be described as an example with reference to fig. 1 and 2 for the inertial sensor 1 according to the first embodiment.

In fig. 1, for convenience of explanation of the internal structure of the inertial sensor 1, the cover 5 is removed and the state is shown. In fig. 1, the wiring of the substrate 2 is omitted.

For convenience of explanation, in each drawing, as three axes orthogonal to each other, an X axis, a Y axis, and a Z axis are shown. The direction along the X axis is referred to as "X direction", the direction along the Y axis is referred to as "Y direction", and the direction along the Z axis is referred to as "Z direction". The tip side of the arrow in each axial direction is referred to as "positive side", the base side is referred to as "negative side", the positive side in the Z direction is referred to as "upper", and the negative side in the Z direction is referred to as "lower". The Z direction is along the vertical direction, and the XY plane is along the horizontal plane. In the present embodiment, the first direction is the Y direction, the second direction is the X direction, and the third direction is the Z direction.

The inertial sensor 1 shown in fig. 1 and 2 can detect acceleration in the Z direction, which is the vertical direction of the sensor element 3. Such an inertial sensor 1 includes: a substrate 2; a sensor element 3 disposed on the substrate 2; and a cover 5 bonded to the substrate 2 and covering the sensor element 3.

As shown in fig. 1, the substrate 2 is expanded in the X direction and the Y direction, and has a thickness in the Z direction. As shown in fig. 2, the substrate 2 is formed with a recess 21 and a recess 21a recessed toward the lower surface side and having different depths. The depth of the recess 21a from the upper surface is deeper than the depth of the recess 21 from the upper surface. The recess 21 and the recess 21a enclose the sensor element 3 inside when viewed from the Z direction in plan view, and are formed larger than the sensor element 3. The concave portions 21 and 21a function as relief portions that suppress contact between the sensor element 3 and the substrate 2. The substrate 2 has a fixing portion 22 and a protrusion 23 protruding from the surface 7, which is the bottom surface of the recess 21, toward the sensor element 3, a first detection electrode 24 and a second detection electrode 25 are disposed on the bottom surface of the recess 21, and a dummy electrode 26 is disposed on the bottom surface of the recess 21 a. The first detection electrode 24 and the second detection electrode 25 have substantially equal areas. The two different detection electrodes are connected to a QV amplifier described later, respectively, and the capacitance difference is detected as an electric signal by a differential detection method. Therefore, the first detection electrode 24 and the second detection electrode 25 are preferably equal in area. The sensor element 3 is joined to the upper surface of the fixing portion 22. The projection 23 is disposed at a position overlapping with a second movable body 38 and a third movable body 40, which will be described later, when viewed from the Z direction in a plan view. In the present embodiment, the position of the lower surface of the sensor element 3 disposed on the substrate 2 coincides with the bonding surface where the substrate 2 and the cover 5 are bonded, but the sensor element 3 may be accommodated in a space enclosed by the substrate 2 and the cover 5, and does not depend on the positional relationship with the bonding surface and the shapes of the recess 21 and the recess 21 a.

When the first movable body 31 does not include the second movable body 38 and the third movable body 40, which will be described later, the protrusion 23 comes into contact with the first movable body 31 when excessive seesaw movement of the first movable body 31 occurs, and thereby the protrusion 23 functions as a stopper for restricting further seesaw movement of the first movable body 31. By providing such a protrusion 23, the first movable body 31, the first detection electrode 24, and the second detection electrode 25 having different potentials can be prevented from being excessively close to each other. Generally, since electrostatic attraction is generated between electrodes having different potentials, if excessive approach occurs, Pull-in occurs as follows: the electrostatic attraction generated between the first movable body 31 and the first and second detection electrodes 24 and 25 causes the first movable body 31 to remain attracted to the first and second detection electrodes 24 and 25 without being restored. In such a state, the inertial sensor 1 cannot normally operate, and therefore, it is important to provide the projection 23 to prevent excessive approach. As described above, since the first movable body 31 has a different potential from the first detection electrode 24 and the second detection electrode 25, the insulating layer 27 is provided on the projection 23 to prevent short-circuiting. Using silicon oxide SiO₂Silicon nitride Si₃N₄Etc. as the material of the insulating layer 27.

For example, a glass substrate containing Na as an active component can be used as the substrate 2⁺Glass material of alkali metal ion of plasma movable ion such as pyrex (registered trade name)Standard) glass, or borosilicate glass such as TEMPAX (registered trademark) glass. However, the substrate 2 is not particularly limited, and for example, a Silicon substrate, a quartz substrate, an SOI (Silicon On Insulator) substrate, or the like may be used.

As shown in fig. 2, the cover 5 is formed with a recessed recess 51 on the upper surface side. The cover 5 accommodates the sensor element 3 in the recess 51 and is joined to the upper surface of the substrate 2. Further, a housing space S for housing the sensor element 3 is formed inside the cover 5 by the cover 5 and the substrate 2. The storage space S is an airtight space, and is preferably filled with an inert gas such as nitrogen, helium, or argon, and is used at a temperature of about-40 to 125 ℃ and at a substantially atmospheric pressure. However, the atmosphere of the storage space S is not particularly limited, and may be, for example, a reduced pressure state or a pressurized state.

As the cover 5, for example, a silicon substrate can be used. However, the present invention is not particularly limited thereto, and for example, a glass substrate or a quartz substrate may be used. The method of bonding the substrate 2 and the lid 5 is not particularly limited, and may be appropriately selected depending on the materials of the substrate 2 and the lid 5, and for example, anodic bonding, activated bonding in which bonding surfaces activated by plasma irradiation are bonded to each other, bonding with a bonding material such as a glass frit, or metal eutectic bonding in which metal films formed on the upper surface of the substrate 2 and the lower surface of the lid 5 are bonded to each other may be used.

The sensor element 3 is formed by vertically processing a conductive silicon substrate doped with impurities such As phosphorus (P), boron (B), and arsenic (As) by etching, particularly by Bosch (Bosch) process which is a deep etching technique.

As shown in fig. 1, the sensor element 3 has: a holding portion 32 engaged with an upper surface of the fixing portion 22; a first movable body 31 swingable about a first rotation axis J1 along a Y direction as a first direction; a first support beam 33 as a first rotation shaft J1 for supporting the first movable body 31; a second movable body 38 swingable about a second rotation axis J2 along the X direction as a second direction orthogonal to the Y direction; a second support beam 37 that connects the first movable body 31 and the second movable body 38 and supports the second movable body 38 as a second rotation axis J2; a third movable body 40 swingable about a third rotation shaft J3 along the X direction; and a third support beam 39 that connects the first movable body 31 and the third movable body 40 and supports the third movable body 40 as a third rotation axis J3. The fixing portion 22 is anodically joined to the holding portion 32, for example, and the first support beam 33 connects the first movable body 31 and the fixing portion 22 via the holding portion 32.

First movable body 31 has a rectangular shape whose longitudinal direction is the X direction when viewed from the Z direction. Further, the first movable body 31 includes, when viewed from the Z direction: a first mass portion 34 and a second mass portion 35 disposed with a first rotation axis J1 along the Y direction therebetween; and third mass portions 36 coupled to both ends of the second mass portion 35 in the Y direction by fourth coupling portions 44. Further, between the second mass portion 35 and the third mass portion 36, a fourth opening portion 48 is provided so that the area of the first mass portion 34 is equal to the area of the second mass portion 35. The first mass portion 34 is located on the X-direction positive side with respect to the first rotation axis J1, and the second mass portion 35 and the third mass portion 36 are located on the X-direction negative side with respect to the first rotation axis J1. The second mass portion 35 and the third mass portion 36 are longer than the first mass portion 34 in the X direction, and the torque around the first rotation axis J1 when the acceleration Az in the Z direction is applied is larger than the first mass portion 34.

Due to this difference in torque, when the acceleration Az is applied, the first movable body 31 performs seesaw-type swinging about the first rotation axis J1. The seesaw-type swinging means that the second mass portion 35 is displaced to the Z-direction negative side when the first mass portion 34 is displaced to the Z-direction positive side, and conversely, the second mass portion 35 is displaced to the Z-direction positive side when the first mass portion 34 is displaced to the Z-direction negative side.

In the first movable body 31, the first mass portion 34 and the second mass portion 35 are coupled by the first coupling portion 41, and the first opening 45 is provided between the first mass portion 34 and the second mass portion 35. In the first opening 45, the holding portion 32 and the first support beam 33 are disposed. In this way, the holding portion 32 and the first support beam 33 are disposed inside the first movable body 31, thereby making it possible to reduce the size of the sensor element 3.

The first movable body 31 has a plurality of through holes formed uniformly over the entire area thereof. This makes it possible to optimize vibration damping due to viscosity. That is, when acceleration is applied during normal operation, the seesaw-type swing can be easily converged by the vibration damping effect. Too high or too low vibration reduction effect can bring negative influence to detection action. In a typical inertial sensor for detecting acceleration, the atmospheric pressure in the housing space S is set to 0.1 to 1.0 times the atmospheric pressure, and the inertial sensor is appropriately designed according to the shape and number of through holes. If a necessary and sufficient vibration damping effect is obtained, the through-holes may be omitted, or the arrangement thereof may be uneven.

In addition, the first coupling portion 41 and the holding portion 32 arranged in the Y direction are coupled to each other by the first support beam 33 extending in the Y direction with respect to the first movable body 31. Therefore, the first movable body 31 can be displaced around the first rotation axis J1 in a see-saw type manner with the first support beam 33 as the first rotation axis J1.

The first mass portion 34 is composed of two mass portions, and is connected by second connecting portions 42 at both ends in the Y direction. Therefore, the first mass portion 34 has the second opening portion 46 in the central portion. When the center line L of the first movable body 31 along the X direction is defined as a line dividing the first movable body 31 by 2 in the Y direction, the second movable body 38 extending in the Y direction is disposed inside the second opening portion 46 and on the positive side of the center line L in the Y direction, and the second support beam 37 connecting both sides of the end portion of the second movable body 38 on the center line L side in the X direction to the two mass portions is disposed. The second support beam 37 extends to the positive side and the negative side in the X direction, and coincides with a second rotation axis J2 for moving the second movable body 38 in the Z direction. The first mass portion 34 is composed of two mass portions, but functions as one mass portion having high rigidity because it is firmly coupled by the second coupling portion 42. In other words, the second linking portion 42 takes charge of the effect of increasing the rigidity of the first mass portion 34. In this way, the parasitic vibration mode of the first mass portion 34 can be suppressed.

Further, a third movable body 40 extending in the Y direction is disposed on the negative side of the second opening 46 in the Y direction with respect to the center line L, and: and two third support beams 39 connecting both sides of the end portion of the third movable body 40 on the center line L side in the X direction to the two mass portions and extending to the positive side and the negative side in the X direction.

The second movable body 38 and the second support beam 37 are disposed line-symmetrically to the third movable body 40 and the third support beam 39 with the center line L as a symmetry axis. In this way, by arranging the second movable body 38 and the second support beam 37 and the third movable body 40 and the third support beam 39 symmetrically, it is possible to equalize the amount of input charge to the QV amplifier described later in a natural state where no acceleration Az is applied, while eliminating the adverse effect of parasitic capacitance. Therefore, the amount of deviation can be detected with high accuracy.

Further, the center of gravity G1 of the second movable body 38 is closer to the second support beam 37 than the center line L, and the center of gravity G2 of the third movable body 40 is closer to the third support beam 39 than the center line L. In other words, the free ends of the second movable body 38 and the third movable body 40 are located on the outer edge side of the first movable body 31 on the opposite side to the side connected to the second support beam 37 and the third support beam 39. Therefore, when an impact having a different amount of displacement in the Z direction is applied to both ends of the first movable body 31 in the Y direction, the free end of the second movable body 38 or the third movable body 40 on the end portion side having the larger amount of displacement comes into contact with the projection 23, and the impact can be reduced. Further, since the second movable body 38, the second support beam 37, the third movable body 40, and the third support beam 39 are disposed in the second opening portion 46 of the first mass portion 34, when an impact is applied from the XY in-plane direction such as the X direction and the Y direction, the distal end portions of the free ends of the second movable body 38 and the third movable body 40 contact the second coupling portion 42 and the first mass portion 34, so that the impact energy can be dissipated, and the breakage of the second support beam 37 and the third support beam 39 can be reduced.

The second support beam 37 coincides with the end portion of the second movable body 38 on the center line L side, and the third support beam 39 coincides with the end portion of the third movable body 40 on the center line L side. In other words, the intervals between the second support beam 37 and the third movable body 40 and the center line L are equal to the intervals between the center line L and the end portions of the second movable body 38 and the third movable body 40 on the center line L side. Therefore, the torsional rigidity of the second support beam 37 and the third support beam 39 about the second rotation axis J2 and the third rotation axis J3 becomes weak, and when the acceleration Az in the Z direction is applied, the free end of the second movable body 38 or the third movable body 40 is displaced further than the first movable body 31 and approaches the first detection electrode 24, so that the detection sensitivity can be improved.

The second mass portion 35 is constituted by two mass portions, and is connected by third connecting portions 43 at both ends in the Y direction, similarly to the first mass portion 34. Therefore, the second mass portion 35 has a third opening 47 in the central portion. Similarly to the first mass portion 34, the second movable body 38, the second support beam 37, the third movable body 40, and the third support beam 39 are disposed in the third opening 47. The second movable body 38, the second support beam 37, the third movable body 40, and the third support beam 39 disposed in the third opening 47 of the second mass portion 35 are disposed line-symmetrically to the second movable body 38, the second support beam 37, the third movable body 40, and the third support beam 39 disposed in the second opening 46 of the first mass portion 34 about the first rotation axis J1 as a symmetry axis. Therefore, the second mass portion 35 can also obtain the same effect as the first mass portion 34. The second mass portion 35 is composed of two mass portions, but functions as one mass portion having high rigidity because it is firmly connected by the third connecting portion 43. In other words, the third linking portion 43 plays a role of increasing the rigidity of the second mass portion 35. In this way, the parasitic vibration mode of the second mass portion 35 can be suppressed.

The second support beam 37 and the third support beam 39 disposed in the first mass portion 34 and the second mass portion 35 have beam shapes extending in the X direction, and therefore function as the second rotation axis J2 and the third rotation axis J3 along the X direction intersecting the first rotation axis J1, and the second movable body 38 connected to the second support beam 37 can be displaced around the second rotation axis J2, and the third movable body 40 connected to the third support beam 39 can be displaced around the third rotation axis J3. Further, the projection 23 provided on the base plate 2 is disposed at a position overlapping with the distal end portions of the free ends of the second movable body 38 and the third movable body 40 when viewed from the Z direction in plan view.

In the present embodiment, the impact resistance from the X direction is improved in the state where the stopper function is provided by causing the second rotation shaft J2 and the third rotation shaft J3 of the second support beam 37 and the third support beam 39 to be in the X direction orthogonal to the first rotation shaft J1 along the Y direction of the first support beam 33, but the present invention is not limited thereto, and the second rotation shaft J2 and the third rotation shaft J3 may not be orthogonal to the first rotation shaft J1. In other words, the angle may be in the range of 90 ° ± 10 ° with respect to the first rotation axis J1. If the second rotation shaft J2 and the third rotation shaft J3 are configured to be line-symmetric with respect to the center line L and the first rotation shaft J1 in this range, the same effects as those of the present embodiment described above can be obtained.

Next, the first detection electrode 24 and the second detection electrode 25 disposed on the bottom surface of the recess 21 and the dummy electrode 26 disposed on the bottom surface of the recess 21a will be described.

As shown in fig. 1 and 2, the first detection electrode 24 is disposed to overlap the first mass portion 34 and the second detection electrode 25 is disposed to overlap the second mass portion 35 when viewed from the Z direction. The first detection electrode 24 and the second detection electrode 25 are provided substantially symmetrically with respect to the first rotation axis J1 when viewed from the Z direction so that capacitances Ca and Cb described later are equal in a natural state where no acceleration Az is applied. In addition, an insulating layer 27 is provided in a portion where the first detection electrode 24 and the second detection electrode 25 overlap the protrusion 23. The insulating layer 27 prevents a short circuit between the first movable body 31 and the first and second detection electrodes 24 and 25.

The dummy electrode 26 is located on the X-direction negative side of the second detection electrode 25 and is provided so as to overlap the third mass portion 36. In this way, by covering the bottom surface of the recess 21a with the dummy electrode 26, the bottom surface of the recess 21a can be suppressed from being charged due to the movement of the alkali metal ions in the substrate 2. Therefore, it is possible to effectively suppress the generation of undesired electrostatic attraction force caused by erroneous operation of the first movable body 31 between the bottom surface of the concave portion 21 and the second mass portion 35. Therefore, the inertial sensor 1 can detect the acceleration Az with higher accuracy.

The first detection electrode 24 and the second detection electrode 25 are electrically connected to a differential QV amplifier, not shown. When the inertial sensor 1 is driven, a drive signal is applied to the sensor element 3, whereby a capacitance Ca is formed between the first mass portion 34 and the first detection electrode 24. Similarly, a capacitance Cb is formed between the second mass portion 35 and the second detection electrode 25. In a natural state where the acceleration Az is not applied, the capacitances Ca and Cb are almost equal to each other.

When the acceleration Az is applied to the inertial sensor 1, the first movable body 31 performs seesaw-type swinging about the first rotation axis J1. The seesaw-like swinging of the first movable body 31 causes a reverse phase change in the gap between the first mass portion 34 and the first detection electrode 24 and the gap between the second mass portion 35 and the second detection electrode 25, and accordingly, the capacitances Ca and Cb are reversed. Therefore, the inertial sensor 1 can detect the acceleration Az based on the difference between the capacitance values of the capacitances Ca and Cb.

Next, the operation of the inertial sensor 1 according to the embodiment will be described with reference to fig. 3 and 4.

Fig. 3 and 4 are diagrams schematically showing the operation of the inertial sensor 1 when accelerations S1 and S2 exceeding measurable maximum values, for example, about 50G, are applied to the inertial sensor 1 as the acceleration Az in the Z direction. The direction of the accelerations S1 and S2 is the Z-direction negative side, and the maximum value of the absolute values of the accelerations S1 and S2 that can be measured is < S1 < S2. For convenience of explanation, the cover 5, the fixing portion 22, and the like are omitted.

As shown in fig. 3, when the inertial sensor 1 is subjected to the acceleration S1 as the acceleration Az in the Z direction, the first movable body 31 performs seesaw-type rocking about the first rotation axis J1, and the second movable body 38 comes into contact with the protrusion 23. At this time, assuming that the shortest distance between the third mass portion 36 and the dummy electrode 26 is a1 and the shortest distance between the second mass portion 35 and the second detection electrode 25 is b1, a1 < b1 is given. The relationship between a1 and b1 is a design item, but in the case of the capacitance detection method, a short circuit between the movable electrode and the detection electrode causes a failure of the subsequent QV amplifier, and therefore, a state where b1 > a1 ≠ 0 is preferable.

The torsional rigidity of the second support beam 37 about the second rotation axis J2 is higher than the torsional rigidity of the first support beam 33 about the first rotation axis J1. Therefore, the displacement amount of the second movable body 38 by the second support beam 37 is smaller than the displacement amount of the first movable body 31 by the first support beam 33, and therefore, the second support beam 37 and the second movable body 38 can function as a stopper. Before the second movable body 38 is in contact with the projection 23, the second support beam 37 does not twist (ね and れ), and therefore, no energy of deformation is accumulated.

Further, the resonance frequency of the second movable body 38 about the second rotation axis J2 becomes 2 times or more the resonance frequency of the first movable body 31 about the first rotation axis J1. By setting the resonance frequency of the second movable body 38 about the second rotation axis J2 to 2 times or more the resonance frequency of the first movable body 31 about the first rotation axis J1, the acceleration Az can be detected in a state where the second movable body 38 is substantially stationary with respect to the first movable body 31, that is, the first movable body 31 and the second movable body 38 can be regarded as one rigid body and seesaw-swings about the first rotation axis J1 when detecting the acceleration Az in the Z direction.

Since the acceleration Az can be detected in a state where the first movable body 31 and the second movable body 38 can be regarded as one rigid body and see seesaw-type swinging about the first rotation axis J1, the influence of the vibration of the second movable body 38 is small, and highly accurate detection can be performed. The second movable body 38 can be used as an electrode for forming the capacitance Ca with the first detection electrode 24 and the capacitance Cb with the second detection electrode 25 together with the first mass portion 34 and the second mass portion 35. Therefore, the capacitances Ca and Cb can be increased, and detection can be performed with higher accuracy.

In the present embodiment, for example, the resonance frequency of the second movable body 38 about the second rotation axis J2 is 1kHz to 2kHz, and the resonance frequency of the first movable body 31 about the first rotation axis J1 is 5 kHz. In order to make the resonance frequency of the second movable body 38 about the second rotation axis J2 2 times or more the resonance frequency of the first movable body 31 about the first rotation axis J1, for example, the torsional rigidity of the second support beam 37 about the second rotation axis J2 may be higher than the torsional rigidity of the first support beam 33 about the first rotation axis J1.

As shown in fig. 4, when an acceleration S2 greater than the acceleration S1 is applied to the inertial sensor 1 as the acceleration Az in the Z direction, the second movable body 38 comes into contact with the protrusion 23, the second movable body 38 is pushed up in the Z direction positive side by the protrusion 23, and the first movable body 31 collides with the concave portion 21 a. At this time, assuming that the shortest distance between the third mass portion 36 and the dummy electrode 26 is a2, the shortest distance b2 between the second mass portion 35 and the second detection electrode 25 is b2 > a2 equal to 0. The second movable body 38 is pushed up toward the Z-direction positive side, and the second support beam 37 is deformed so as to twist about the second rotation axis J2. That is, the energy of deformation is accumulated in the second support beam 37. As described above, the second support beam 37 is deformed so as to twist about the second rotation axis J2, and a part of the impact energy applied to the inertial sensor 1 by the acceleration S2 is accumulated in the second support beam 37 and absorbed, so that the impact energy of the collision of the first movable body 31 with the concave portion 21a is alleviated, and the sticking is less likely to occur.

Further, when the first movable body 31 excessively seesaws, the second movable body 38 contacts the projection 23, and the second support beam 37 is deformed so as to twist around the second rotation axis J2, and a part of the impact energy applied to the inertial sensor 1 is accumulated and absorbed in the second support beam 37, so that the impact with the projection 23 can be reduced, the damage of the second movable body 38, the projection 23, and the like can be reduced, and further seesaw swinging of the first movable body 31 can be restricted. Therefore, the second support beam 37 and the second movable body 38 can be made to function as dampers that absorb impact.

As with the second support beam 37 and the second movable body 38, the third support beam 39 and the third movable body 40 are also higher in torsional rigidity about the third rotation axis J3 than the first support beam 33, and the third support beam 39 and the third movable body 40 can function as stoppers, as in the case of the second support beam 37 and the second movable body 38. Further, since the resonance frequency of the third movable body 40 about the third rotation axis J3 is 2 times or more the resonance frequency of the first movable body 31 about the first rotation axis J1, the influence of the vibration of the third movable body 40 is small, and the detection can be performed with high accuracy.

When the second movable body 38 vibrates about the second rotation axis J2 and the third movable body 40 vibrates about the third rotation axis J3, the vibration modes are separated into the in-phase mode and the out-of-phase mode. The resonance frequency in the in-phase mode about the second rotation axis J2 of the second movable body 38 and the resonance frequency in the in-phase mode about the third rotation axis J3 of the third movable body 40 become 2 times or more the resonance frequency about the first rotation axis J1 of the first movable body 31. By setting the resonance frequency of the second movable body 38 in the in-phase mode about the second rotation axis J2 and the resonance frequency of the third movable body 40 in the in-phase mode about the third rotation axis J3 to be 2 times or more the resonance frequency of the first movable body 31 about the first rotation axis J1, the second movable body 38 and the third movable body 40 can be regarded as being in a substantially stationary state with respect to the first movable body 31 when the acceleration Az in the Z direction is detected. That is, it can be considered that the second movable body 38 and the third movable body 40 are formed as one rigid body with the first movable body 31 and perform seesaw-type swinging about the first rotation axis J1. The acceleration Az can be detected in such a state by setting the resonance frequency in the in-phase mode about the second rotation axis J2 of the second movable body 38 and the resonance frequency in the in-phase mode about the third rotation axis J3 of the third movable body 40 to be 2 times or more the resonance frequency about the first rotation axis J1 of the first movable body 31.

The inertial sensor 1 of the present embodiment includes: a second movable body 38 and a third movable body 40 which are displaceable by deformation of a second support beam 37 and a third support beam 39 provided on the first movable body 31; and a protrusion 23 provided on the base plate 2, overlapping the second movable body 38 and the third movable body 40 when viewed from the Z direction in plan view, and protruding toward the second movable body 38 and the third movable body 40. Therefore, when the second movable body 38 and the third movable body 40 come into contact with the projection 23 when the first movable body 31 excessively seesaws, the second support beam 37 and the third support beam 39 are deformed so as to twist around the second rotation axis J2 and the third rotation axis J3, and therefore, the impact with the projection 23 can be reduced, and the breakage of the first movable body 31 and the projection 23 can be reduced.

In addition, the second opening 46 and the third opening 47 of the first movable body 31 are provided with the second movable body 38, the second support beam 37, the third movable body 40, and the third support beam 39. Therefore, when an impact is applied from the XY in-plane direction such as the X direction and the Y direction, the distal end portions of the free ends of the second movable body 38 and the third movable body 40 contact the second coupling portion 42 and the third coupling portion 43, and the first mass portion 34 and the second mass portion 35. This can dissipate the impact energy and reduce the breakage of the second support beam 37 and the third support beam 39. Even if the second opening 46 and the third opening 47 are provided in a large area in the first movable body 31, they are connected by the second connecting portion 42 and the third connecting portion 43, and therefore, they have high rigidity and are less likely to generate a parasitic vibration mode in the first mass portion 34 and the second mass portion 35. This can suppress damage due to the parasitic vibration mode when excessive seesaw vibration is generated by a strong impact.

2. Second embodiment

Next, an inertial sensor 1a according to a second embodiment will be described with reference to fig. 5. For convenience of explanation, fig. 5 shows a state where the cover 5 is removed.

The inertial sensor 1a of the present embodiment is the same as the inertial sensor 1 of the first embodiment except that the structure of the sensor element 3a is different as compared with the inertial sensor 1 of the first embodiment. Differences from the first embodiment will be mainly described, and descriptions of the same matters will be omitted.

As shown in fig. 5, in the sensor element 3a of the inertial sensor 1a, the second movable body 38a and the third movable body 40a provided in the second opening 46 and the third opening 47 have end portions 381, 401 on the side of the center line L closer to the center line L than the second support beam 37 and the third support beam 39. In other words, the intervals between the center line L and the end portions 381, 401 of the second movable body 38a and the third movable body 40a on the center line L side are shorter than the intervals between the center line L and the second support beam 37 and the third support beam 39.

With such a configuration, the impact resistance of the second support beam 37 and the third support beam 39 against an impact from the XY in-plane directions such as the X direction and the Y direction can be improved, and the same effect as that of the inertial sensor 1 according to the first embodiment can be obtained.

3. Third embodiment

Next, an inertial sensor 1b according to a third embodiment will be described with reference to fig. 6. For convenience of explanation, fig. 6 shows a state where the cover 5 is removed.

The inertial sensor 1b of the present embodiment is the same as the inertial sensor 1 of the first embodiment except for the structure of the sensor element 3b, as compared with the inertial sensor 1 of the first embodiment. Differences from the first embodiment will be mainly described, and descriptions of the same matters will be omitted.

As shown in fig. 6, the sensor element 3b of the inertial sensor 1b is provided with a first elastic portion 61 between one end 311 of the first movable body 31b in the Y direction and the second movable body 38, and a second elastic portion 62 between the other end 312 of the first movable body 31b in the Y direction and the third movable body 40, in the first mass portion 34 and the second mass portion 35.

The first elastic portion 61 and the second elastic portion 62 are beam-shaped extending in the X direction, and both ends of the first elastic portion 61 and the second elastic portion 62 provided on the first mass portion 34 side are connected to the first mass portion 34, and both ends of the first elastic portion 61 and the second elastic portion 62 provided on the second mass portion 35 side are connected to the second mass portion 35.

The first elastic portion 61 and the second elastic portion 62 have a beam shape extending in the X direction, and therefore have elasticity in the Y direction. Therefore, when the second movable body 38 and the third movable body 40 are displaced in the X direction by the impact from the X direction, and the end portions on the free end sides of the second movable body 38 and the third movable body 40 come into contact with the first elastic portion 61 and the second elastic portion 62, the impact can be alleviated.

With such a configuration, it is possible to reduce breakage of the second movable body 38 and the third movable body 40 against an impact from the X direction, improve the impact resistance of the second support beam 37 and the third support beam 39, and obtain the same effect as the inertial sensor 1 of the first embodiment.

4. Fourth embodiment

Next, an inertial sensor 1c according to a fourth embodiment will be described with reference to fig. 7 and 8. For convenience of explanation, fig. 7 shows a state where the cover 5 is removed.

The inertial sensor 1c of the present embodiment is the same as the inertial sensor 1 of the first embodiment except that the structure of the sensor element 3c is different from that of the inertial sensor 1 of the first embodiment. Differences from the first embodiment will be mainly described, and descriptions of the same matters will be omitted.

As shown in fig. 7 and 8, the sensor element 3c of the inertial sensor 1c includes: the first elastic portion 61c provided between the one end 311 of the first movable body 31c in the Y direction and the second movable body 38 and the second elastic portion 62c provided between the other end 312 of the first movable body 31c in the Y direction and the third movable body 40, of the first mass portion 34 and the second mass portion 35. The third elastic portion 63 is disposed between the first movable body 31 and the second movable body 38 in the X direction, and the fourth elastic portion 64 is disposed between the first movable body 31 and the third movable body 40 in the X direction.

The first elastic portion 61c and the second elastic portion 62c are respectively constituted by a first portion extending in the Y direction from the second coupling portion 42 and the third coupling portion 43, and a beam-shaped second portion extending in the X direction from an end thereof. The third elastic portion 63 and the fourth elastic portion 64 are each composed of a third portion extending in the X direction from the first movable body 31 and a beam-shaped fourth portion extending in the Y direction from an end thereof.

Two first elastic portions 61c and two second elastic portions 62c each having a second portion extending to the X-direction positive side and a second portion extending to the X-direction negative side are disposed between the one end 311 and the second movable body 38 and between the other end 312 and the third movable body 40, respectively. The third elastic portions 63 are disposed on the X-direction positive side and the X-direction negative side of the second movable body 38, the fourth portions of the third elastic portions 63 extend toward the Y-direction positive side, the fourth elastic portions 64 are disposed on the X-direction positive side and the X-direction negative side of the third movable body 40, and the fourth portions of the fourth elastic portions 64 extend toward the Y-direction negative side.

The first elastic portion 61c and the second elastic portion 62c are beam-shaped with the second portion extending in the X direction, and therefore have elasticity with respect to the Y direction. Therefore, the impact from the X direction can be alleviated. The third elastic portion 63 and the fourth elastic portion 64 are beam-shaped with the fourth portion extending in the Y direction, and therefore have elasticity in the X direction. Therefore, the impact from the Y direction can be alleviated. The first elastic portion 61c, the second elastic portion 62c, the third elastic portion 63, and the fourth elastic portion 64 may have elasticity for relaxing an impact, and the shape thereof may not be limited. Therefore, the shape may be not only a beam but also a folded spring shape, a labyrinth shape, a truss structure shape, a rigid frame structure shape, or the like.

With such a configuration, it is possible to reduce breakage of the second movable body 38 and the third movable body 40 against an impact from the X direction and the Y direction, improve the impact resistance of the second support beam 37 and the third support beam 39, and obtain the same effect as the inertial sensor 1 of the first embodiment.

5. Fifth embodiment

Next, an inertial sensor 1d according to a fifth embodiment will be described with reference to fig. 9. For convenience of explanation, fig. 9 shows a state where the cover 5 is removed.

The inertial sensor 1d of the present embodiment is the same as the inertial sensor 1 of the first embodiment except that the structure of the sensor element 3d is different from that of the inertial sensor 1 of the first embodiment. Differences from the first embodiment will be mainly described, and descriptions of the same matters will be omitted.

As shown in fig. 9, the sensor element 3d of the inertial sensor 1d has a shorter interval from the center of gravity G1 of the second movable body 38d to the center line L than to the center line L of the second support beam 37d, and a shorter interval from the center of gravity G2 of the third movable body 40d to the center line L than to the center line L of the third support beam 39 d. In other words, the free ends of the second movable body 38d and the third movable body 40d are positioned closer to the center line L than the second support beam 37d and the third support beam 39d, and the second support beam 37d and the third support beam 39d are positioned on the outer edge side of the first movable body 31. Therefore, when an impact is applied in the rotational direction within the XY plane using the intersection of the center line L and the first rotation axis J1 as the rotation axis, the free ends of the second movable body 38d and the third movable body 40d approach the rotation axis, and therefore the amount of displacement due to the impact can be reduced. Therefore, the influence of the impact in the rotation direction in the XY plane can be reduced, and the same effect as that of the inertial sensor 1 according to the first embodiment can be obtained.

6. Sixth embodiment

Next, an inertial sensor 1e according to a sixth embodiment will be described with reference to fig. 10. Fig. 10 corresponds to a cross-sectional view taken along line a-a in fig. 1.

In the inertial sensor 1e of the present embodiment, an SOI substrate is used as the substrate 2 e. The SOI substrate is a substrate in which a single crystal silicon layer 73 is formed on an insulating layer 72 on a silicon substrate 71. In the present embodiment, the substrate is not limited to single crystal silicon, and a polysilicon layer may be formed on the insulating layer 72 on the silicon substrate 71. A cover 5e is joined to the substrate 2e, and the sensor element 3 is housed therein. Therefore, compared to the inertial sensor 1 of the first embodiment, the configuration is the same as that of the inertial sensor 1 of the first embodiment except that the substrate 2e and the cover 5e are different. Differences from the first embodiment will be mainly described, and descriptions of the same matters will be omitted.

In the present embodiment, the lid 5e is joined to the substrate 2e, but more specifically, joined via the joining material 80. The bonding material 80 may be any material that maintains sufficient hermeticity, being a frit material, a metal eutectic layer, a solder sealing material, or the like. First movable body 31 formed on substrate 2e via insulating layer 72 is made of single crystal silicon or polycrystalline silicon, and peripheral portion 75 using the same single crystal silicon or polycrystalline silicon is formed. The cover 5e of the inertial sensor 1e is bonded to the peripheral portion 75 via the bonding material 80. As shown in fig. 10, the cover 5e of the inertial sensor 1e is provided with a protrusion 23e protruding toward the second movable body 38 and the third movable body 40 on the surface 8 serving as the bottom surface of the recess 51 of the cover 5 e. Therefore, when the first movable body 31 undergoes excessive seesaw-type rocking, the protrusion 23e provided on the cover 5e comes into contact with the second movable body 38 and the third movable body 40, whereby the same effect as that of the inertial sensor 1 according to the first embodiment can be obtained. If the projection 23e is optimally designed, the depth of the recess 21 of the substrate does not need to be changed, and the recess 21a is not needed.

7. Seventh embodiment

Next, an inertial sensor 1f according to a seventh embodiment will be described with reference to fig. 11. Fig. 11 corresponds to a cross-sectional view taken along line a-a in fig. 1.

The inertial sensor 1f of the present embodiment is the same as the inertial sensor 1 of the first embodiment except that the substrate 2f and the sensor element 3f have different structures as compared with the inertial sensor 1 of the first embodiment. Differences from the first embodiment will be mainly described, and descriptions of the same matters will be omitted. In addition, as in the sixth embodiment, an SOI substrate is used as the substrate 2f, and the recess 21a is not formed.

As shown in fig. 11, the sensor element 3f of the inertial sensor 1f is provided with a protrusion 23f protruding toward the surface 7 serving as the bottom surface of the recess 21 of the substrate 2f on the second movable body 38 and the third movable body 40. Therefore, when excessive seesaw-type rocking occurs in the first movable body 31, the protrusions 23f provided on the second movable body 38 and the third movable body 40 come into contact with the surface 7 of the base plate 2f, whereby the same effects as those of the inertial sensor 1 according to the first embodiment can be obtained.

8. Eighth embodiment

Next, an inertial sensor 1g according to an eighth embodiment will be described with reference to fig. 12. Fig. 12 corresponds to a cross-sectional view taken along line a-a in fig. 1.

The inertial sensor 1g of the present embodiment is the same as the inertial sensor 1 of the first embodiment except that the substrate 2g and the sensor element 3g have different structures as compared with the inertial sensor 1 of the first embodiment. Differences from the first embodiment will be mainly described, and descriptions of the same matters will be omitted. In addition, as in the sixth embodiment, an SOI substrate is used as the substrate 2g, and the recess 21a is not formed.

As shown in fig. 12, the sensor element 3g of the inertial sensor 1g is provided with a protrusion 23g protruding toward the surface 8 serving as the bottom surface of the recess 51 of the cover 5 on the second movable body 38 and the third movable body 40. Therefore, when the first movable body 31 undergoes excessive seesaw-type rocking, the protrusions 23g provided on the second movable body 38 and the third movable body 40 come into contact with the surface 8 of the cover 5, whereby the same effects as those of the inertial sensor 1 according to the first embodiment can be obtained.

9. Ninth embodiment

Next, an inertial measurement unit 2000 including inertial sensors 1 to 1g according to a ninth embodiment will be described with reference to fig. 13 and 14. In the following description, a configuration in which the inertial sensor 1 is applied will be described by way of example.

An Inertial Measurement Unit (IMU) 2000 shown in fig. 13 is a device for detecting an amount of Inertial motion such as a posture and a behavior of a moving body such as an automobile or a robot. The inertial measurement unit 2000 functions as a so-called six-axis motion sensor including an acceleration sensor that detects accelerations Ax, Ay, and Az in directions along three axes, and an angular velocity sensor that detects angular velocities ω x, ω y, and ω z around the three axes.

The inertial measurement unit 2000 is a rectangular parallelepiped having a substantially square planar shape. Screw holes 2110 as fixing portions are formed near two apexes in the diagonal direction of the square. The inertia measurement apparatus 2000 can be fixed to the mounting surface of the mounting object such as an automobile by inserting two screws into the two screw holes 2110. By selecting components and changing the design, for example, the size can be reduced to a size that can be mounted on a smartphone or a digital camera.

The inertial measurement unit 2000 includes a housing 2100, a joint member 2200, and a sensor module 2300, and is configured to: a bonding member 2200 is interposed in the housing 2100, and the sensor module 2300 is inserted. In addition, the sensor module 2300 has an inner housing 2310 and a base plate 2320.

The housing 2100 has a rectangular parallelepiped shape having a substantially square planar shape, and has screw holes 2110 formed near two vertexes located in a diagonal direction of the square, as in the entire shape of the inertial measurement unit 2000. The housing 2100 has a box shape, and the sensor module 2300 is housed therein.

The inner housing 2310 is a member for supporting the substrate 2320, and is shaped to be received in the outer housing 2100. The inner case 2310 is formed with a recess 2311 for preventing contact with the substrate 2320 and an opening 2312 for exposing a connector 2330 described later. Such an inner housing 2310 is engaged with the outer housing 2100 via an engaging member 2200. Further, a substrate 2320 is bonded to the lower surface of the inner case 2310 via an adhesive.

As shown in fig. 14, a connector 2330, an angular velocity sensor 2340Z for detecting an angular velocity around the Z axis, an acceleration sensor unit 2350 for detecting acceleration in each of the X, Y, and Z axes, and the like are mounted on the upper surface of a substrate 2320. Further, an angular velocity sensor 2340X for detecting an angular velocity around the X axis and an angular velocity sensor 2340Y for detecting an angular velocity around the Y axis are attached to the side surface of the substrate 2320.

The acceleration sensor unit 2350 includes at least the above-described inertial sensor 1 for detecting the acceleration in the Z direction, and can detect the acceleration in one axis direction, or the accelerations in two axis directions or three axis directions as necessary. The angular velocity sensors 2340x, 2340y, and 2340z are not particularly limited, and for example, vibration gyro sensors using coriolis force can be used.

A control IC2360 is mounted on the lower surface of the substrate 2320. A control IC2360 as a control Unit that performs control based on a detection signal output from the inertial sensor 1 is an MCU (Micro Controller Unit) and incorporates a storage Unit including a nonvolatile memory, an a/D converter, and the like, and controls each part of the inertial measurement Unit 2000. The storage unit stores a program that defines the order and contents for detecting acceleration and angular velocity, a program that digitizes the detected data and incorporates packet data, accompanying data, and the like. In addition, the substrate 2320 has a plurality of electronic components mounted thereon.

Since the acceleration sensor unit 2350 including the inertial sensor 1 is used in the inertial measurement unit 2000, the inertial measurement unit 2000 having excellent shock resistance and high reliability is obtained.