Inertial sensor, electronic device, and moving body

Abstract

To provide an inertial sensor, an electronic device, and a movable body, which reduce damage of a sensor element due to an excessive impact.SOLUTION: An inertial sensor 1 includes: a substrate 2; a fixing portion 22 that is provided on the substrate 2; a first movable body 31 that faces the substrate 2 and that is displaceable with a first support beam 33 as a first rotation axis; the first support beam 33 that is arranged in a first direction and that couples the first movable body 31 and the fixing portion 22; a second movable body 38 that is displaceable due to deformation of a second support beam 37; the second support beam 37 that is arranged in a second direction intersecting the first direction and that couples the first movable body 31 and the second movable body 38; and a protrusion 23 that is provided on the substrate 2 or the second movable body 38, overlaps the second movable body 38 in plan view from a third direction intersecting the first direction and the second direction, and protrudes toward the second movable body 38 or the substrate 2.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an inertial sensor, an electronic device, and a moving body.

Background Art

[0002] In recent years, inertial sensors manufactured using MEMS (Micro Electro Mechanical Systems) technology have been developed. As such an inertial sensor, for example, Patent Document 1 describes a substrate, a movable body that swings like a seesaw around a rotation axis along the vertical direction with respect to the substrate, and a detection electrode provided on the substrate. The inertial sensor has a first movable part and a second movable part of the movable body having different rotational moments around the rotation axis, and first and second detection electrodes arranged at positions facing each of them, and can detect the acceleration in the vertical direction based on the change in capacitance between them. Further, this inertial sensor is provided with a protrusion on the substrate to prevent the end of the movable body from coming into contact with the substrate when the movable body swings excessively like a seesaw.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when the movable body and the protrusion collide due to excessive seesaw swinging in the inertial sensor described in Patent Document 1, since the rigidity of the movable body and the protrusion is high, the impact cannot be absorbed and there is a risk of damaging the movable body and the protrusion.

Means for Solving the Problems

[0005] The inertial sensor includes a substrate, a fixed portion provided on the substrate, a first movable body facing the substrate and displaceable about a first rotation axis with a first support beam, a first support beam connecting the first movable body and the fixed portion arranged in a first direction, a second movable body displaceable by deformation of a second support beam, a second support beam connecting the first movable body and the second movable body arranged in a second direction intersecting the first direction, and a protrusion provided on the substrate or the second movable body, overlapping the second movable body in a plan view from a third direction intersecting the first direction and the second direction, and protruding toward the second movable body or the substrate.

[0006] The electronic device includes the inertial sensor described above, and a control unit that performs control based on a detection signal output from the inertial sensor.

[0007] The moving body includes the inertial sensor described above, and a control unit that performs control based on a detection signal output from the inertial sensor.

Brief Description of the Drawings

[0008]

Figure 1

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Mode for Carrying Out the Invention

[0009] 1. First Embodiment First, regarding the inertial sensor 1 according to the first embodiment, an acceleration sensor that detects acceleration in the vertical direction (Z direction) will be taken as an example, and it will be described with reference to FIGS. 1 and 2. In FIG. 1, for the sake of convenience in explaining the internal configuration of the inertial sensor 1, the state where the lid 5 is removed is illustrated. Also, in FIG. 1, the wiring in the recess 21 of the substrate 2 is omitted.

[0010] Also, for the sake of convenience in explanation, FIGS. show three axes orthogonal to each other, namely the X axis, the Y axis, and the Z axis. Also, the direction along the X axis is called the "X direction", the direction along the Y axis is called the "Y direction", and the direction along the Z axis is called the "Z direction". Also, the tip side of the arrow in each axis direction is called the "plus side", the base end side is called the "minus side", the plus side in the Z direction is also called "up", and the minus side in the Z direction is also called "down". Also, the Z direction is along the vertical direction, and the XY plane is along the horizontal plane. Also, in this embodiment, the first direction is the Y direction, the second direction is the X direction, and the third direction is the Z direction.

[0011] The inertial sensor 1 shown in FIGS. 1 and 2 can detect the acceleration of the sensor element 3 in the vertical direction (Z direction). Such an inertial sensor 1 has a substrate 2, a sensor element 3 disposed on the substrate 2, and a lid 5 joined to the substrate 2 and covering the sensor element 3.

[0012] As shown in FIG. 1, the substrate 2 extends in the X and Y directions and has a thickness in the Z direction. Further, as shown in FIG. 2, the substrate 2 is formed with a recess 21 that opens on the upper surface side. This recess 21 encloses the sensor element 3 inside in a plan view from the Z direction and is formed larger than the sensor element 3. The recess 21 functions as a relief portion that suppresses contact between the sensor element 3 and the substrate 2. Further, the substrate 2 has a fixing portion 22 and a protrusion 23 that protrude from the bottom surface of the recess 21 toward the sensor element 3 side, and a first detection electrode 24, a second detection electrode 25, and a dummy electrode 26 are arranged on the bottom surface of the recess 21. And the sensor element 3 is joined to the upper surface of the fixing portion 22. Further, the protrusion 23 is arranged at a position overlapping with a second movable body 38, which will be described later, in a plan view from the Z direction.

[0013] When the first movable body 31 undergoes excessive seesaw oscillation, the protrusion 23 contacts the second movable body 38 that is connected to the first movable body 31, thereby functioning as a stopper that restricts further seesaw oscillation of the first movable body 31. By providing such a protrusion 23, it is possible to suppress excessive approach or wide-area contact between the first movable body 31 and the first detection electrode 24 and the second detection electrode 25, which have different potentials from each other, and the first movable body 31 can be effectively suppressed from being attracted to the first detection electrode 24 or the second detection electrode 25 by the electrostatic attraction generated between the first movable body 31 and the first detection electrode 24 and the second detection electrode 25 and remaining unable to return. The occurrence of "sticking" can be effectively suppressed.

[0014] As the substrate 2, for example, a glass material containing alkali metal ions, which are mobile ions such as Na + etc., or a glass substrate made of borosilicate glass such as Pyrex (registered trademark) glass or Tempax (registered trademark) glass can be used. However, the substrate 2 is not particularly limited, and for example, a silicon substrate or a ceramic substrate may be used.

[0015] Further, as shown in FIG. 1, on the bottom surface of the recess 21 in the substrate 2, a first detection electrode 24, a second detection electrode 25, and a dummy electrode 26 that overlap the sensor element 3 in a plan view are arranged.

[0016] As shown in Fig. 2, the lid 5 is formed with a recess 51 that opens on the lower surface side. The lid 5 houses the sensor element 3 in the recess 51 and is joined to the upper surface of the substrate 2. Then, the lid 5 and the substrate 2 form a storage space S inside for housing the sensor element 3. The storage space S is an airtight space, and it is preferable that an inert gas such as nitrogen, helium, or argon is enclosed, the operating temperature is about -40°C to 125°C, and it is at approximately atmospheric pressure. However, the atmosphere of the storage space S is not particularly limited, and for example, it may be in a reduced pressure state or a pressurized state.

[0017] As the lid 5, for example, a silicon substrate can be used. However, it is not particularly limited thereto, and for example, a glass substrate or a ceramic substrate may be used. Also, the joining method between the substrate 2 and the lid 5 is not particularly limited and may be appropriately selected according to the materials of the substrate 2 and the lid 5. For example, anodic bonding, activation bonding in which the joined surfaces activated by plasma irradiation are joined, bonding with a bonding material such as glass frit, diffusion bonding in which the metal films formed on the upper surface of the substrate 2 and the lower surface of the lid 5 are joined, etc. can be used.

[0018] The sensor element 3 is formed, for example, by etching a conductive silicon substrate doped with impurities such as phosphorus (P), boron (B), and arsenic (As), and particularly by patterning using the Bosch process, which is a deep trench etching technique. As shown in Fig. 1, the sensor element 3 includes a holding portion 32 joined to the upper surface of the fixed portion 22, a first movable body 31 displaceable around a rotation axis J1 as a first rotation axis along the Y axis with respect to the holding portion 32, a first support beam 33 connecting the first movable body 31 and the holding portion 32, a second movable body 38 displaceable around a rotation axis J2 as a second rotation axis along the X axis with respect to the holding portion 32, and a second support beam 37 connecting the first movable body 31 and the second movable body 38 arranged in the X direction. The fixed portion 22 and the holding portion 32 are, for example, anodically bonded, and the first support beam 33 connects the first movable body 31 and the fixed portion 22 via the holding portion 32.

[0019] The first movable body 31 has a rectangular shape with the X direction as the longitudinal direction in a plan view from the Z direction. Further, in a plan view from the Z direction, the first movable body 31 includes a first mass portion 34 and a second mass portion 35 disposed with a rotation axis J1 along the Y axis therebetween, and a third mass portion 36 connected to the second mass portion 35. The first mass portion 34 is located on the plus side in the X direction with respect to the rotation axis J1, and the second mass portion 35 and the third mass portion 36 are located on the minus side in the X direction with respect to the rotation axis J1. Also, the second mass portion 35 and the third mass portion 36 are longer in the X direction than the first mass portion 34, and the rotational moment about the rotation axis J1 when the acceleration Az in the Z direction is applied is larger than that of the first mass portion 34.

[0020] Due to this difference in rotational moment, when the acceleration Az is applied, the first movable body 31 rocks like a seesaw about the rotation axis J1. Note that the seesaw rocking means that when the first mass portion 34 is displaced to the plus side in the Z direction, the second mass portion 35 is displaced to the minus side in the Z-axis direction, and conversely, when the first mass portion 34 is displaced to the minus side in the Z-axis direction, the second mass portion 35 is displaced to the plus side in the Z-axis direction.

[0021] Further, in the first movable body 31, the first mass portion 34 and the second mass portion 35 are connected by a first connecting portion 39, and an opening 45 is formed between the first mass portion 34 and the second mass portion 35. And a holding portion 32 and a first support beam 33 are disposed in the opening 45. Thus, by disposing the holding portion 32 and the first support beam 33 inside the first movable body 31, miniaturization of the sensor element 3 can be achieved. Also, the first movable body 31 has a plurality of through holes formed uniformly over its entire area. Thereby, damping due to viscosity can be reduced. However, the through holes may be omitted, or their arrangement may not be uniform.

[0022] Also, in the first movable body 31, the first connecting portion 39 and the holding portion 32 arranged in the Y direction are connected by a first support beam 33 extending in the Y direction. Therefore, using the first support beam 33 as the rotation axis J1, the first movable body 31 can be displaced by seesaw rocking about the rotation axis J1.

[0023] The first mass portion 34 is composed of two mass portions and is connected by a second connecting portion 40 at the central portion in the Y direction. On both sides of the second connecting portion 40 in the Y direction, second movable bodies 38 extending in the Y direction from the second connecting portion 40 side are arranged. Both sides in the X direction of the end portion of the second movable body 38 on the second connecting portion 40 side and the two mass portions are connected by second support beams 37 extending in the X direction, respectively. More specifically, the second support beam 37 arranged on the plus side in the Y direction of the second connecting portion 40 connects the second movable body 38 extending on the plus side in the Y direction arranged in the X direction and the two mass portions of the first mass portion 34. The second support beam 37 arranged on the minus side in the Y direction of the second connecting portion 40 connects the second movable body 38 extending on the minus side in the Y direction arranged in the X direction and the two mass portions of the first mass portion 34.

[0024] Similar to the first mass portion 34, the second mass portion 35 is composed of two mass portions and is connected by a second connecting portion 40 at the central portion in the Y direction. On both sides of the second connecting portion 40 in the Y direction, second movable bodies 38 extending in the Y direction from the second connecting portion 40 side are arranged. Both sides in the X direction of the end portion of the second movable body 38 on the second connecting portion 40 side and the two mass portions are connected by second support beams 37 extending in the X direction, respectively. Further, the end portion on the minus side in the X direction of the second mass portion 35 is connected to the third mass portion 36 by a third connecting portion 41. An opening 46 is provided between the second mass portion 35 and the third mass portion to make the areas of the XY planes of the first mass portion 34 and the second mass portion 35 equal.

[0025] Since the second support beams 37 arranged on the first mass portion 34 and the second mass portion 35 are in a beam shape extending in the X direction, they act as a rotation axis J2 along the X axis intersecting the rotation axis J1 and can displace the second movable bodies 38 connected to the second support beams 37 around the rotation axis J2. Further, in a plan view from the Z direction, a protrusion 23 provided on the substrate 2 is arranged at a position overlapping the tip portion on the side opposite to the side connected to the second support beam 37 of the second movable body 38. Therefore, when the second movable body 38 comes into contact with the protrusion 23 when excessive seesaw oscillation occurs in the first movable body 31, the second support beam 37 is deformed so as to be twisted around the rotation axis J2, and the impact with the protrusion 23 can be reduced. After reducing damage to the second movable body 38 and the protrusion 23, further seesaw oscillation of the first movable body 31 can be restricted. Accordingly, the second support beam 37 and the second movable body 38 function as a damper that absorbs impact.

[0026] Note that the torsional rigidity of the second support beam 37 around the rotation axis J2 is higher than the torsional rigidity of the first support beam 33 around the rotation axis J1. Therefore, when the same force is applied, the displacement amount of the second movable body 38 of the second support beam 37 becomes smaller than the displacement amount of the first movable body 31 by the first support beam 33. Thus, the second support beam 37 and the second movable body 38 can function as a stopper.

[0027] In the present embodiment, one set consists of one second support beam 37, one second movable body 38, and one protrusion 23, and four sets are arranged. In a plan view from the Z direction, two sets are arranged on the first mass portion 34 and the second mass portion 35 with the Y direction parallel to the rotation axis J1 interposed therebetween. In the first mass portion 34 and the second mass portion 35, two sets of the second support beam 37, the second movable body 38, and the protrusion 23 are arranged so as to sandwich the second connecting portion 40 and face each other. Since four sets of the second support beam 37, the second movable body 38, and the protrusion 23 are symmetrically arranged with the Y direction interposed therebetween, unnecessary displacement around the rotation axis J1 is less likely to occur. Also, since four sets of the second support beam 37, the second movable body 38, and the protrusion 23 are symmetrically arranged with the X direction interposed therebetween, unnecessary displacement around the rotation axis J2 can be made less likely to occur.

[0028] Also, by setting the rotation axis J2 of the second support beam 37 in the direction along the X axis orthogonal to the rotation axis J1 along the Y axis of the first support beam 33, the impact resistance from the X direction can be improved in a state having a damper function and a stopper function. That is, when the rotation axis J1 of the first support beam 33 and the rotation axis J2 of the second support beam 37 are in the direction along the Y axis, the first movable body 31 is largely displaced in the X direction with respect to an impact from the X direction, and characteristic deterioration is likely to occur.

[0029] Next, the first detection electrode 24, the second detection electrode 25, and the dummy electrode 26 disposed on the bottom surface of the recess 21 will be described. As shown in FIGS. 1 and 2, in a plan view from the Z direction, the first detection electrode 24 is disposed overlapping the first mass portion 34, and the second detection electrode 25 is disposed overlapping the second mass portion 35. These first detection electrode 24 and second detection electrode 25 are provided substantially symmetrically with respect to the rotation axis J1 in a plan view from the Z direction so that the electrostatic capacitances Ca and Cb described later become equal in a natural state where no acceleration Az is applied.

[0030] Also, the dummy electrode 26 is located on the minus X direction side of the second detection electrode 25 and is provided overlapping the third mass portion 36. By covering the bottom surface of the recess 21 with the dummy electrode 26 in this way, it is possible to suppress the charging of the bottom surface of the recess 21 accompanying the movement of alkali metal ions in the substrate 2. Therefore, it is possible to effectively suppress the occurrence of an unintended electrostatic attraction that leads to malfunction of the first movable body 31 between the bottom surface of the recess 21 and the second mass portion 35. As a result, the inertial sensor 1 can detect the acceleration Az with higher accuracy.

[0031] Although not shown, when the inertial sensor 1 is driven, a drive voltage is applied to the sensor element 3 via a wiring not shown, and the first detection electrode 24 and the QV amplifier, and the second detection electrode 25 and another QV amplifier are connected by wirings not shown, respectively. Thereby, an electrostatic capacitance Ca is formed between the first mass portion 34 and the first detection electrode 24, and an electrostatic capacitance Cb is formed between the second mass portion 35 and the second detection electrode 25. In a natural state where no acceleration Az is applied, the electrostatic capacitances Ca and Cb are substantially equal to each other.

[0032] When acceleration Az is applied to the inertial sensor 1, the first movable body 31 swings like a seesaw about the rotation axis J1. Due to this seesaw swing of the first movable body 31, 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 change in antiphase, and accordingly, the capacitances Ca and Cb change in antiphase with each other. Therefore, the inertial sensor 1 can detect the acceleration Az based on the changes in the capacitances Ca and Cb.

[0033] The inertial sensor 1 of the present embodiment includes a second movable body 38 that can be displaced by the deformation of a second support beam 37 provided on the first movable body 31, and a protrusion 23 that is provided on the substrate 2, overlaps the second movable body 38 in a plan view from the Z direction, and protrudes toward the second movable body 38. Therefore, when the second movable body 38 and the protrusion 23 come into contact when an excessive seesaw swing occurs in the first movable body 31, the second support beam 37 deforms so as to twist around the rotation axis J2, so that the impact with the protrusion 23 can be reduced, and the breakage of the second movable body 38 and the protrusion 23 can be reduced.

[0034] Also, by arranging a plurality of second support beams 37 extending in the X direction with the second connecting portion 40 interposed therebetween and facing each other, the length of the second support beam 37 in the X direction can be made longer, and the impact with the protrusion 23 can be further reduced.

[0035] Also, since the torsional rigidity of the second support beam 37 is higher than the torsional rigidity of the first support beam 33, the displacement amount of the second movable body 38 becomes smaller than the displacement amount of the first movable body 31, and excessive seesaw swing of the first movable body 31 can be restricted.

[0036] 2. Second Embodiment Next, the inertial sensor 1a according to the second embodiment will be described with reference to FIG. 3. Note that FIG. 3 corresponds to a cross-sectional view taken along line A-A in FIG. 1.

[0037] The inertial sensor 1a of this embodiment is the same as the inertial sensor 1 of the first embodiment, except that the structures of the sensor element 3a and the substrate 2a are different. Note that the description will focus on the differences from the aforementioned first embodiment, and the description of the same matters will be omitted.

[0038] As shown in FIG. 3, the sensor element 3a of the inertial sensor 1a is provided with a protrusion 23a that protrudes toward the substrate 2a on the second movable body 38a. Therefore, when excessive seesaw oscillation occurs in the first movable body 31, the protrusion 23a provided on the second movable body 38a contacts the bottom surface of the recess 21 of the substrate 2a, so that the same effect as that of the inertial sensor 1 of the first embodiment can be obtained.

[0039] 3. Third Embodiment Next, the inertial sensor 1b according to the third embodiment will be described with reference to FIG. 4. Note that FIG. 4 corresponds to a plan view at the position of part B in FIG. 1.

[0040] The inertial sensor 1b of this embodiment is the same as the inertial sensor 1 of the first embodiment, except that the structures of the second movable body 38b and the second connecting portion 40b are different. Note that the description will focus on the differences from the aforementioned first embodiment, and the description of the same matters will be omitted.

[0041] As shown in FIG. 4, the inertial sensor 1b is provided with a convex portion 42 that protrudes toward the second connecting portion 40b on the side connected to the second support beam 37 of the second movable body 38b. Further, at a position facing the convex portion 42 of the second connecting portion 40b, a concave portion 43 that opens toward the convex portion 42 is provided in order to avoid contact with the convex portion 42 as the second movable body 38b is displaced. By providing the convex portion 42, when the second movable body 38b is displaced around the rotation axis J2, the stress generated in the connecting portion between the second movable body 38b and the second support beam 37 can be dispersed to the connecting portion between the convex portion 42 and the second support beam 37. Therefore, the concentration of stress in the connecting portion can be alleviated, and breakage at the connecting portion can be suppressed. Thus, the inertial sensor 1b has improved mechanical strength at the connecting portion between the second support beam 37 and the second movable body 38b and can obtain the same effects as the inertial sensor 1 of the first embodiment.

[0042] 4. Fourth Embodiment Next, the inertial sensor 1c according to the fourth embodiment will be described with reference to FIG. 5. Note that FIG. 5 corresponds to a plan view of the position of portion B in FIG. 1.

[0043] 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 second movable body 38c and the second connecting portion 40c is different. Note that the description will focus on the differences from the first embodiment described above, and descriptions of similar matters will be omitted.

[0044] As shown in FIG. 5, the inertial sensor 1c is provided with a convex portion 42c protruding toward the second connecting portion 40c on the side connected to the second support beam 37c of the second movable body 38c. The connecting portion between the second movable body 38c and the second support beam 37c and the connecting portion between the convex portion 42c and the second support beam 37c are curved surfaces. Further, at a position facing the convex portion 42c of the second connecting portion 40c, in order to avoid contact with the convex portion 42c as the second movable body 38c is displaced, a concave portion 43c is provided which opens toward the convex portion 42c side and has curved surfaces at two corners inside the concave. By making the connecting portion a curved surface, when the second movable body 38c is displaced around the rotation axis J2, stress concentration at the connecting portion between the second support beam 37c and the second movable body 38c and at the connecting portion between the second support beam 37c and the convex portion 42c can be alleviated, and breakage at the connecting portion can be suppressed. Therefore, the inertial sensor 1c has improved mechanical strength at the connecting portion between the second support beam 37c and the second movable body 38c, and can obtain the same effects as the inertial sensor 1 of the first embodiment.

[0045] 5. Fifth Embodiment Next, the inertial sensor 1d according to the fifth embodiment will be described with reference to FIG. 6. Note that FIG. 6 corresponds to a plan view at the position of portion C in FIG. 1.

[0046] The inertial sensor 1d of this embodiment is the same as the inertial sensor 1 of the first embodiment, except that the structure of the first movable body 31d and the second support beam 37d is different from that of the inertial sensor 1 of the first embodiment. Note that the description will focus on the differences from the above-described first embodiment, and the description of the same matters will be omitted.

[0047] As shown in FIG. 6, the inertial sensor 1d has a curved surface at the connecting portion between the first movable body 31d and the second support beam 37d. Further, the curved surface shapes of the connecting portions on both sides sandwiching the second support beam 37d are line-symmetric with respect to the X-axis. In this embodiment, the curved surface of the connecting portion is a quarter circle in plan view from the Z direction, but it is not limited to this, and it may be a semi-circle. By making the connecting portion a curved surface, it is possible to relieve the concentration of stress on the connecting portion when the second movable body 38 is displaced around the rotation axis J2, and it is possible to suppress breakage at the connecting portion. Therefore, the inertial sensor 1d has improved mechanical strength at the connecting portion between the first movable body 31d and the second support beam 37d, and can obtain the same effects as the inertial sensor 1 of the first embodiment.

[0048] 6. Sixth Embodiment Next, the inertial sensor 1e according to the sixth embodiment will be described with reference to FIG. 7. Note that FIG. 7 corresponds to a plan view at the position of part C in FIG. 1.

[0049] The inertial sensor 1e of this embodiment is the same as the inertial sensor 1 of the first embodiment, except that the structure of the first movable body 31e and the second support beam 37e is different. Note that the description will focus on the differences from the first embodiment described above, and the description of the same matters will be omitted.

[0050] As shown in FIG. 7, in the inertial sensor 1e, the connecting portion between the first movable body 31e and the second support beam 37e is a curved surface. Also, the curved surface shapes of the connecting portions on both sides sandwiching the second support beam 37e are circular with a diameter larger than the length in the Y direction of the gap between the first movable body 31e and the second support beam 37e and the length in the Y direction of the gap between the second connecting portion 40e and the second support beam 37e in a plan view from the Z direction, and are line-symmetrical with respect to the X axis. Note that the curved surface shapes of the connecting portions on both sides sandwiching the second support beam 37d are not limited to circular shapes with the same diameter, and circular shapes with different diameters may also be acceptable. By making the connecting portion a curved surface, it is possible to relieve the concentration of stress on the connecting portion when the second movable body 38 is displaced around the rotation axis J2, and it is possible to suppress breakage at the connecting portion. Therefore, the inertial sensor 1e has improved mechanical strength at the connecting portion between the first movable body 31e and the second support beam 37e, and can obtain the same effects as the inertial sensor 1 of the first embodiment.

[0051] 7. Seventh Embodiment Next, the inertial sensor 1f according to the seventh embodiment will be described with reference to FIG. 8. Note that FIG. 8 corresponds to a plan view of the position of part D in FIG. 1.

[0052] The inertial sensor 1f of this embodiment is the same as the inertial sensor 1 of the first embodiment, except that the structure of the second movable body 38f is different. Note that the description will focus on the differences from the first embodiment described above, and the description of similar matters will be omitted.

[0053] As shown in FIG. 8, the inertial sensor 1f is provided with notches 44 facing the first movable body 31 at the ends of the second movable body 38f on the side opposite to the side to which the second support beam 37 is connected. More specifically, notches 44 are provided on both sides in the X direction at the tip of the second movable body 38f. By providing the notches 44 in the second movable body 38f, it is possible to prevent the first movable body 31 and the second movable body 38f from colliding due to impacts from the X direction or Y direction, etc., and damaging the first movable body 31 or the second movable body 38f. Therefore, the inertial sensor 1f is excellent in impact resistance and can obtain the same effects as the inertial sensor 1 of the first embodiment.

[0054] Furthermore, the connecting portion between the portion of the second movable body 38f on the second support beam 37 side and the notch 44 is a convex curved surface on the first movable body 31 side. Thereby, it is possible to prevent the convex curved surface on the first movable body 31 side and the first movable body 31 from colliding due to impacts from the X direction or Y direction, etc., and damaging the first movable body 31 or the second movable body 38f.

[0055] 8. Eighth Embodiment Next, the inertial sensor 1g according to the eighth embodiment will be described with reference to FIG. 9. Note that FIG. 9 shows a state where the lid 5 is removed for convenience of explanation.

[0056] The inertial sensor 1g of the present embodiment is the same as the inertial sensor 1 of the first embodiment, except that the structure of the sensor element 3g is different. Note that the description will focus on the differences from the above-described first embodiment, and the description of the same matters will be omitted.

[0057] As shown in FIG. 9, in the inertial sensor 1g, a plurality of second movable bodies 38g are arranged with the second connecting portion 40g interposed therebetween on the first mass portion 34g and the second mass portion 35g of the first movable body 31g, and the first mass portion 34g, the second mass portion 35g, and the second movable body 38g are connected by a spiral-shaped second support beam 37g. The second support beam 37g is a spiral spring and can displace the second movable body 38g in the Z direction. Also, a protrusion 23 protruding from the substrate 2 to the second movable body 38g is arranged at a position overlapping the second movable body 38g in a plan view from the Z direction. Therefore, when the second movable body 38g and the protrusion 23 come into contact when excessive seesaw rocking occurs in the first movable body 31g, the second support beam 37g is deformed so as to bend, and the impact with the protrusion 23 can be reduced. After reducing the breakage of the second movable body 38g and the protrusion 23, further seesaw rocking of the first movable body 31g can be restricted. Thus, the inertial sensor 1g functions as a damper in which the second support beam 37g and the second movable body 38g absorb impacts, and the same effects as those of the inertial sensor 1 of the first embodiment can be obtained.

[0058] 9. Ninth Embodiment Next, as an example of an electronic device including the inertial sensors 1 to 1g according to the ninth embodiment, a smartphone 1200 will be described. In the following description, a configuration applying the inertial sensor 1 will be exemplified and described.

[0059] As shown in FIG. 10, the smartphone 1200 as an electronic device incorporates the above-described inertial sensor 1. Detection data as a detection signal such as acceleration detected by the inertial sensor 1 is transmitted to the control unit 1201 of the smartphone 1200. The control unit 1201 includes a CPU (Central Processing Unit), recognizes the posture and behavior of the smartphone 1200 from the received detection data, and changes the display image displayed on the display unit 1208, or emits a warning sound or a sound effect, or drives a vibration motor to vibrate the main body. In other words, the smartphone 1200 can perform motion sensing and change the display content, generate sounds or vibrations, etc. based on the measured posture and behavior. In particular, when executing a game application, a realistic sense of presence can be experienced.

[0060] In addition to the above-described smartphone 1200, the inertial sensors 1 to 1g can be applied to, for example, personal computers, digital still cameras, tablet terminals, watches, smartwatches, inkjet printers, laptop personal computers, televisions, smart glasses, wearable terminals such as HMDs (head-mounted displays), video cameras, video tape recorders, car navigation devices, drive recorders, pagers, electronic notebooks, electronic dictionaries, electronic translators, calculators, electronic game devices, toys, word processors, workstations, videophones, security television monitors, electronic binoculars, POS terminals, medical devices, fish finders, various measuring devices, mobile terminal base station devices, vehicles, railway vehicles, airplanes, helicopters, ships, and various instruments, flight simulators, network servers, etc.

[0061] 10. Tenth Embodiment Next, as an example of a moving body equipped with the inertial sensors 1 to 1g according to the tenth embodiment, an automobile 1500 will be described. In the following description, a configuration applying the inertial sensor 1 will be exemplified and described.

[0062] As shown in FIG. 11, the automobile 1500 as a moving body has a built-in inertial sensor 1. For example, the inertial sensor 1 can detect the movement and posture of the vehicle body 1501. The detection signal of the inertial sensor 1 is supplied to a vehicle body posture control device 1502 as a control unit for controlling the movement and posture of the vehicle body 1501. The vehicle body posture control device 1502 detects the posture of the vehicle body 1501 based on the signal, and can control the hardness and softness of the suspension or control the brakes of individual wheels 1503 according to the detection result.

[0063] In addition, the inertial sensors 1 to 1g can be widely applied to other electronic control units (ECUs) such as keyless entry systems, immobilizers, car navigation systems, car air conditioners, antilock brake systems (ABS), airbags, tire pressure monitoring systems (TPMS), engine control systems (engine systems), control devices for inertial navigation for autonomous driving, and battery monitors for hybrid vehicles and electric vehicles.

[0064] In addition to the above examples, the inertial sensors 1 to 1g can also be used, for example, in the movement and posture control of bipedal walking robots, trains, etc., the remote control or autonomous flight control of radio-controlled airplanes, radio-controlled helicopters, and drones, the movement and posture control of agricultural machinery or construction machinery, and the control of rockets, artificial satellites, ships, and AGVs (automated guided vehicles).

Description of Reference Numerals

[0065] 1, 1a, 1b, 1c, 1d, 1e, 1f, 1g... inertial sensors, 2... substrate, 3... sensor element, 5... lid, 21... recess, 22... fixing part, 23... protrusion, 24... first detection electrode, 25... second detection electrode, 26... dummy electrode, 31... first movable body, 32... holding part, 33... first support beam, 34... first mass part, 35... second mass part, 36... third mass part, 37... second support beam, 38... second movable body, 39... first connecting part, 40... second connecting part, 41... third connecting part, 42... convex part, 43... recess, 44... notch, 45, 46... opening, 51... recess, 1200... smartphone as an electronic device, 1500... automobile as a moving body, Ca, Cb... capacitance, J1... rotation axis as the first rotation axis, J2... rotation axis as the second rotation axis, S... storage space.

Claims

1. When the three mutually orthogonal axes are the X-axis, the Y-axis, and the Z-axis, A substrate; a sensor element facing the substrate in a Z direction along the Z axis; A protrusion that restricts the oscillation of the sensor element; Including, The sensor element comprises: A first movable body including two mass portions aligned in an X direction along the X axis; a connecting portion that connects the two mass portions and extends in the X direction; A holder joined to the substrate; a first movable body that connects the first movable body and the holding portion and extends in the Y direction along the Y axis; A support beam; a second support beam connected to the two mass portions and extending in the X direction; The second support beam is disposed between the two mass portions and extends in the Y direction from the second support beam side. A second movable body that is displaceable around the second support beam as a rotation axis; Including, the sensor element is displaceable about the first support beam as a rotation axis, The second movable body overlaps with the protrusion in a plan view from the Z-axis direction. Inertial sensor.

2. In claim 1, The second movable body extends to a side opposite to the connecting portion in a plan view from the Z-axis direction. 、 The second support beam is The positive side of the X-axis of the end of the second movable body on the side of the connecting portion and the positive side of the two mass portions A positive support beam connecting the one side and the other side; A microstrip line connecting the negative side of the X-axis at the end and the other of the two mass portions. Eggplant side support beam; Including, Inertial sensor.

3. In claim 2, The second movable body includes a portion that is connected to the second support beam in a plan view from the Z-axis direction. A protrusion is provided that protrudes toward the connecting portion. Inertial sensor.

4. In claim 3, The connecting portion has a recessed portion provided at a position facing the protruding portion in a plan view from the Z-axis direction. It is being Inertial sensor.

5. In claim 4, A connection portion between the second movable body and the second support beam is a curved surface. Inertial sensor.

6. In claim 4 or 5, When viewed in a plan view from the Z-axis direction, the corners of the recess are curved. Inertial sensor.

7. In any one of claims 1 to 6, A connection portion between the first movable body and the second support beam is a curved surface. Inertial sensor.

8. In claim 7, The shape of the curved surface of the connection portion between the first movable body and the second support beam is When viewed in a plan view from the Z-axis direction, it is a quarter circle or a semicircle. Inertial sensor.

9. In claim 7, The shape of the curved surface of the connection portion between the first movable body and the second support beam is When viewed in a plane from the Z-axis direction, The length of a gap between the mass portion and the second support beam in the Y direction; Or, the length of the gap between the connecting portion and the second support beam in the Y direction is circular with a diameter greater than Inertial sensor.

10. In any one of claims 1 to 9, The second movable body has an end portion on the opposite side to the second support beam side, the end portion being opposed to the mass portion. A notch is provided. Inertial sensor.

11. In claim 10, When viewed in a plane from the Z-axis direction, A connecting portion between the second support beam side portion of the second movable body and the cutout portion is A curved surface that is convex toward the first movable body side, The end of the cutout portion opposite to the second support beam side is angular. Inertial sensor.

12. In any one of claims 1 to 11, The protrusion is provided on the substrate. Inertial sensor.

13. In any one of claims 1 to 12, A fixing portion is provided on the substrate, The holding portion is joined to the fixing portion. Inertial sensor.

14. In any one of claims 1 to 13, The torsional rigidity of the second support beam is higher than the torsional rigidity of the first support beam. Inertial sensor.

15. An inertial sensor according to any one of claims 1 to 14; A control unit that performs control based on a detection signal output from the inertial sensor; Including electronic devices.

16. An inertial sensor according to any one of claims 1 to 14; A control unit that performs control based on a detection signal output from the inertial sensor; Including, a moving object.

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