Patent Application
20240337676
The present application is based on, and claims priority from JP Application Ser. No. 2023-063289, filed Apr. 10, 2023, the disclosure of which is hereby incorporated by reference herein in its entirety.
The present disclosure relates to an inertial sensor and an inertial measurement apparatus including the inertial sensor.
In recent years, an inertial sensor using a micro electro mechanical system (MEMS) structure is developed. As such an inertial sensor, JP-A-2021-32819 discloses an acceleration sensor that detects an acceleration in the Z-axis direction.
The acceleration sensor disclosed in JP-A-2021-32819 includes a first conductor, a first electrode held by the first conductor, a second conductor, and a second electrode held by the second conductor, in which a length of the first electrode in the height direction is shorter than a length of the first conductor in the height direction, and a length of the second electrode in the height direction is longer than a length of the second conductor in the height direction.
When an excessive acceleration is applied to such an acceleration sensor, there is a problem in that cracks or chips occur in the MEMS structure such as the first conductor and the first electrode.
According to an aspect of the present disclosure, there is provided an inertial sensor including a substrate, a lid provided to face the substrate, a movable frame provided between the substrate and the lid, a comb-teeth movable electrode provided in the movable frame, and a protrusion provided on at least one of the substrate or the lid and overlapping a tip end or a base part of the comb-teeth movable electrode in a plan view.
According to another aspect of the present disclosure, there is provided an inertial measurement apparatus including the inertial sensor described above.
Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
In each of the following drawings, in order to make each component easier to see, the scale of the dimension may be different depending on the component.
Further, for convenience of explanation, three axes including an X axis, a Y axis, and a Z axis, which are orthogonal to each other, are illustrated, a tip end side of an arrow illustrating an axis direction is referred to as a “+side”, and a base end side is referred as a “−side”. Further, in the following, a direction parallel to the X axis is referred to as an “X-axis direction”, a direction parallel to the Y axis is referred to as a “Y-axis direction”, and a direction parallel to the Z axis is referred to as a “Z-axis direction”. Further, in the following, viewing in the Z-axis direction is referred to as “plan view”, and viewing of a cross section including the z axis from the Y-axis direction is referred to as “cross-sectional view”.
Further, in the following description, for example, with respect to a substrate, the description of “on the substrate” refers to any of a case of being disposed to come into contact with the substrate, a case of being disposed on the substrate via another structure, or a case of being disposed so that a part comes into contact on the substrate and a part is disposed via another structure. Further, the description of the upper surface of a certain configuration indicates the surface of the configuration on the + side in the Z-axis direction, for example, the “upper surface of the electrode” indicates the surface of the electrode on the + side in the Z-axis direction. Further, the description of the lower surface of a certain configuration indicates the surface of the configuration on the-side in the Z-axis direction, for example, the “lower surface of the electrode” indicates the surface of the electrode on the-side in the Z-axis direction.
A schematic configuration of an inertial sensor 100 according to Embodiment 1 will be described with reference to
The inertial sensor 100 is a physical amount sensor that detects a change in physical amount due to displacement of a substantially inverted U-shaped movable frame 21, as a change in capacitance. In the present embodiment, the inertial sensor 100 is an acceleration sensor that measures an acceleration in the Z-axis direction based on the displacement of the movable frame 21.
As illustrated in
The support substrate 1 has a cavity 1c including a recess, and a mount 16, a mount 26, and a protrusion 31 are provide in the cavity 1c.
In the present embodiment, the support substrate 1 is made of a silicon substrate and can be formed by patterning the silicon substrate. The support substrate 1 may be a glass substrate or a ceramic substrate.
The lid 2 has a cavity 2c including a recess, and a protrusion 30 is provided in the cavity 2c.
In the present embodiment, the lid 2 is made of a glass substrate and can be formed by patterning the glass substrate. The lid 2 may be a silicon substrate or a ceramic substrate.
The element 3 is provided in an accommodation space S including the cavity 1c and the cavity 2c.
The element 3 is made of, for example, a silicon substrate doped with impurities, such as phosphorus (P) and boron (B), and can be formed by patterning the silicon substrate.
As illustrated in
The detector Z includes a movable electrode and a fixed electrode.
The movable electrode includes the movable frame 21, a first comb-teeth movable electrode 22a, a second comb-teeth movable electrode 22b, a fixing area 25, and a beam 27. These portions are integrally formed and electrically coupled to each other.
The movable frame 21 has a substantially inverted U shape. The movable frame 21 includes a first extension 21a and a second extension 21b which are extending in the Y-axis direction, and a coupler 21c which is extending in an X-axis direction.
The coupler 21c of the movable frame 21 is provided with the first comb-teeth movable electrode 22a and the second comb-teeth movable electrode 22b.
The first comb-teeth movable electrode 22a and the second comb-teeth movable electrode 22b extend along the Y-axis direction, respectively, and have ends which are coupled to the coupler 21c on the + side in the Y-axis direction.
In the present embodiment, a joint part is, for example, a part at which the first comb-teeth movable electrode 22a is coupled to the coupler 21c. More specifically, when a joint is an end of the first comb-teeth movable electrode 22a on fixed end side, the joint part includes the joint and the peripheral part thereof. Further, in the present embodiment, the tip end is, for example, an end of the first comb-teeth movable electrode 22a on the free end side, and the base part is, for example, a part close to the joint of the first comb-teeth movable electrode 22a in the first comb-teeth movable electrode 22a. The same applies to other electrodes and frames.
The ends of the first extension 21a and the second extension 21b in the movable frame 21 on the-side in the Y-axis direction are fixed to the fixing area 25 via the beam 27.
The fixing area 25 is bonded to the upper surface of the mount 26 of the support substrate 1.
The beam 27 functions as a spring. Specifically, the beam 27 is a torsion bar.
When the movable frame 21 receives an inertial force in the Z-axis direction, the beam 27 is twisted using the fixing area 25 as an anchor. Due to such a twisting action, the movable frame 21 swings in the Z-axis direction using the beam 27 as a rotation axis.
In this manner, the movable electrode has a structure referred to as a single-sided seesaw structure.
The fixed electrode includes a first fixed frame 11a, a second fixed frame 11b, a first comb-teeth fixed electrode 12a, and a second comb-teeth fixed electrode 12b.
Each of the first fixed frame 11a and the second fixed frame 11b is bonded to the upper surface of the mount 16 of the support substrate 1.
The first comb-teeth fixed electrode 12a extends along the Y-axis direction, and has one end which is coupled to the first fixed frame 11a on the-side in the Y-axis direction.
The second comb-teeth fixed electrode 12b extends along the Y-axis direction, and has one end which is coupled to the second fixed frame 11b on the-side in the Y-axis direction.
The first comb-teeth fixed electrode 12a is electrically coupled to an electrode pad 6a via wiring 5a.
The second comb-teeth fixed electrode 12b is electrically coupled to an electrode pad 6b via wiring 5b.
The first comb-teeth movable electrode 22a and the second comb-teeth movable electrode 22b are electrically coupled to an electrode pad 6c via wiring 5c.
The support substrate 1 has the protrusion 31. Further, the lid 2 has the protrusion 30. Although not illustrated, the plan shape of the protrusion 30 is substantially the same as that of the protrusion 31.
Both the protrusion 31 and the protrusion 30 are stoppers for suppressing the significant vibration of the first comb-teeth movable electrode 22a, the second comb-teeth movable electrode 22b, the first comb-teeth fixed electrode 12a, and/or the second comb-teeth fixed electrode 12b.
In order to cause the protrusion 31 and the protrusion 30 to function as the stoppers, the protrusion 31 and the protrusion 30 are disposed at positions overlapping the first comb-teeth movable electrode 22a, the second comb-teeth movable electrode 22b, the first comb-teeth fixed electrode 12a, and/or the second comb-teeth fixed electrode 12b in a plan view.
In the present embodiment, the protrusion 31 and the protrusion 30 overlap the tip ends of the first comb-teeth movable electrode 22a and the second comb-teeth movable electrode 22b in a plan view. Further, the protrusion 31 and the protrusion 30 overlap the base parts of the first comb-teeth fixed electrode 12a and the second comb-teeth fixed electrode 12b in a plan view.
In the present embodiment, the protrusion 31 and the protrusion 30 are disposed at a position overlapping each other in a plan view, but the protrusion 31 and the protrusion 30 may be disposed at positions not overlapping each other in a plan view. For example, the protrusion 31 may be disposed at a position overlapping the tip ends of the first comb-teeth movable electrode 22a and the second comb-teeth movable electrode 22b in a plan view, and the protrusion 30 may be disposed at a position overlapping the base parts of the first comb-teeth movable electrode 22a and the second comb-teeth movable electrode 22b in a plan view.
Further, the disposition of either the protrusion 31 or the protrusion 30 may be omitted.
Further, the protrusion 31 may include a plurality of protrusions. For example, when the protrusion 31 includes two protrusions, one protrusion 31 may be provided to overlap the tip end of the first comb-teeth movable electrode 22a, and another protrusion 31 may be provided to overlap the tip end of the second comb-teeth movable electrode 22b.
Further, the protrusion 30 may include a plurality of protrusions. For example, when the protrusion 30 includes two protrusions, one protrusion 30 may be provided to overlap the tip end of the first comb-teeth movable electrode 22a, and another protrusion 30 may be provided to overlap the tip end of the second comb-teeth movable electrode 22b.
When an excessive acceleration is applied to the inertial sensor 100, the first comb-teeth movable electrode 22a and/or the second comb-teeth movable electrode 22b comes into contact with the protrusion 31 or the protrusion 30 before the vibration width exceeds a measurement range and becomes excessively large. Further, the first comb-teeth fixed electrode 12a and/or the second comb-teeth fixed electrode 12b comes into contact with the protrusion 31 or the protrusion 30 before the vibration width becomes excessively large.
In other words, the first comb-teeth movable electrode 22a, the second comb-teeth movable electrode 22b, the first comb-teeth fixed electrode 12a, and the second comb-teeth fixed electrode 12b are limited by the protrusion 31 and/or the protrusion 30 so that the vibration width does not become excessively large.
Therefore, the inertial sensor 100 according to the present embodiment includes the protrusion 31 and/or the protrusion 30. Therefore, even when an excessive acceleration is applied to the inertial sensor 100, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth movable electrode 22a, the second comb-teeth movable electrode 22b, the first comb-teeth fixed electrode 12a, and/or the second comb-teeth fixed electrode 12b.
Further, the protrusion 31 suppresses the first comb-teeth movable electrode 22a, the second comb-teeth movable electrode 22b, the first comb-teeth fixed electrode 12a, and/or the second comb-teeth fixed electrode 12b from coming into contact with or colliding with the bottom surface of the cavity 1c. Further, the protrusion 30 suppresses the first comb-teeth movable electrode 22a, the second comb-teeth movable electrode 22b, the first comb-teeth fixed electrode 12a, and/or the second comb-teeth fixed electrode 12b from coming into contact with or colliding with the bottom surface of the cavity 2c.
In other words, the first comb-teeth movable electrode 22a, the second comb-teeth movable electrode 22b, the first comb-teeth fixed electrode 12a, and/or the second comb-teeth fixed electrode 12b is protected so as not to come into contact with or collide with the bottom surface of the cavity 1c by the protrusion 31. Further, the first comb-teeth movable electrode 22a, the second comb-teeth movable electrode 22b, the first comb-teeth fixed electrode 12a, and/or the second comb-teeth fixed electrode 12b is protected so as not to come into contact with or collide with the bottom surface of the cavity 2c by the protrusion 30.
Therefore, the inertial sensor 100 according to the present embodiment includes the protrusion 31 and/or the protrusion 30. Therefore, even when an excessive acceleration is applied to the inertial sensor 100, the occurrence of cracks or chips can be suppressed in the first comb-teeth movable electrode 22a, the second comb-teeth movable electrode 22b, the first comb-teeth fixed electrode 12a, and/or the second comb-teeth fixed electrode 12b.
Further, the protrusion 31 and/or the protrusion 30 has an effect of suppressing the first comb-teeth movable electrode 22a, the second comb-teeth movable electrode 22b, the first comb-teeth fixed electrode 12a, and/or the second comb-teeth fixed electrode 12b from adhering to the support substrate 1 or the lid 2.
The detector Z includes a detector ZA and a detector ZB. Each of the detector ZA and the detector ZB detects the acceleration in the Z-axis direction.
The detector ZA includes the first comb-teeth movable electrode 22a, and the first comb-teeth fixed electrode 12a adjacent to the first comb-teeth movable electrode 22a. Further, the detector ZB includes a plurality of second comb-teeth movable electrodes 22b and a plurality of second comb-teeth fixed electrodes 12b.
As illustrated in
The first comb-teeth movable electrode 22a has the same thickness as the thickness of the movable frame 21 in the Z-axis direction from the joint part to a certain range, but has a reduced thickness in the Z-axis direction mainly in a region facing the first comb-teeth fixed electrode 12a.
On the other hand, the first comb-teeth fixed electrode 12a has the same thickness as the thickness of the first fixed frame 11a in the Z-axis direction over the entire area from the joint part to the tip end.
The second comb-teeth fixed electrode 12b has a recess R2. The recess R2 is a part obtained by partially recessing a part of the thickness of the second comb-teeth fixed electrode 12b in the Z-axis direction.
The second comb-teeth fixed electrode 12b has the same thickness as the thickness of the second fixed frame 11b in the Z-axis direction from the joint part to a certain range, but has a reduced thickness in the Z-axis direction mainly in a region facing the second comb-teeth movable electrode 22b.
On the other hand, the second comb-teeth movable electrode 22b has the same thickness as the thickness of the movable frame 21 in the Z-axis direction over the entire area from the joint part to the tip end.
In this way, the thickness of the first comb-teeth movable electrode 22a and the thickness of the second comb-teeth fixed electrode 12b are partially reduced. Therefore, the inertial sensor 100 causes the facing area between the first comb-teeth movable electrode 22a and the first comb-teeth fixed electrode 12a to be reduced in the detector ZA when an acceleration on the + side in the Z-axis direction occurs, and causes the facing area between the second comb-teeth movable electrode 22b and the second comb-teeth fixed electrode 12b to be reduced in the detector ZB when the acceleration on the-side in the Z-axis direction occurs.
Therefore, the inertial sensor 100 according to the present embodiment can detect the acceleration on the + side in the Z-axis direction and the acceleration on the-side in the Z-axis direction by detecting the reduction in the facing areas between the detectors ZA and ZB, as the change in the capacitance.
A recess R3 is provided in a part of the coupler 21c of the movable frame 21. The recess R3 eliminates unevenness of the mass of the coupler 21c of the movable frame 21 in the X-axis direction due to the recess R1. Therefore, the deviation of the rotational motion due to the acceleration of the movable frame 21 in the Z-axis direction can be corrected.
The embodiments of the protrusion 31 and the protrusion 30 described above may be variously modified. Specific modification aspects of the protrusion 31 and the protrusion 30 will be described below as examples.
A protrusion 32 indicates a protrusion according to Modification Example 1. The protrusion 32 corresponds to the protrusion 31 and/or the protrusion 30 described above. In
The protrusion 32 overlaps the base part of the first comb-teeth movable electrode 22a and the base part of the second comb-teeth movable electrode 22b in a plan view. Further, the protrusion 32 overlaps the tip end of the first comb-teeth fixed electrode 12a and the tip end of the second comb-teeth fixed electrode 12b in a plan view.
A protrusion 33 indicates a protrusion according to Modification Example 2. The protrusion 33 corresponds to the protrusion 31 and/or the protrusion 30 described above. In
The protrusion 33 overlaps the joint part and the base part of the first comb-teeth movable electrode 22a and the joint part and the base part of the second comb-teeth movable electrode 22b in a plan view. Further, the protrusion 33 overlaps the tip end of the first comb-teeth fixed electrode 12a and the tip end of the second comb-teeth fixed electrode 12b in a plan view.
A protrusion 34 indicates a protrusion according to Modification Example 3. The protrusion 34 corresponds to the protrusion 31 and/or the protrusion 30 described above. In
In a plan view, the protrusion 34 overlaps the joint part and the base part of the second comb-teeth movable electrode 22b and does not overlap the first comb-teeth movable electrode 22a.
When the protrusion is not provided due to routing of the wiring or the like, a configuration in which some of the first comb-teeth movable electrode 22a and the second comb-teeth movable electrode 22b do not overlap the protrusions may be provided as in Modification Example 3. When the protrusion 34 is provided, it is preferable that a plurality of protrusions 34 is provided such that the first comb-teeth movable electrode 22a and the second comb-teeth movable electrode 22b overlap any one of the plurality of protrusions 34.
A protrusion 35 and a protrusion 36 indicate protrusions according to Modification Example 4. The protrusion 35 corresponds to the protrusion 31 and/or the protrusion 30 described above. The protrusion 36 corresponds to the protrusion 31 and/or the protrusion 30 described above. In
The protrusion 35 overlaps the joint part and the base part of the first comb-teeth movable electrode 22a and the joint part and the base part of the second comb-teeth movable electrode 22b in a plan view.
The protrusion 36 overlaps the joint part and the base part of the first comb-teeth fixed electrode 12a and the joint part and the base part of the second comb-teeth fixed electrode 12b in a plan view.
A protrusion 37 indicates a protrusion according to Modification Example 5. The protrusion 37 corresponds to the protrusion 31 and/or the protrusion 30 described above. In
The protrusion 37 overlaps from the base part to the tip end of the first comb-teeth movable electrode 22a and from the base part to the tip end of the second comb-teeth movable electrode 22b in a plan view. Further, the protrusion 37 overlaps from the joint part to the tip end of the first comb-teeth fixed electrode 12a and from the joint part to the tip end the second comb-teeth fixed electrode 12b in a plan view. The protrusion 37 may overlap the joint part of the first comb-teeth movable electrode 22a and/or the joint part of the second comb-teeth movable electrode 22b. Further, the protrusion 37 may not overlap the joint part of the first comb-teeth fixed electrode 12a and/or the joint part of the second comb-teeth fixed electrode 12b. In other words, the protrusion 37 overlaps from the base part to the tip end of the first comb-teeth fixed electrode 12a and from the base part to the tip end of the second comb-teeth fixed electrode 12b in a plan view.
As described above, the inertial sensor 100 according to the present embodiment includes the support substrate 1 as a substrate, the lid 2 provided to face the support substrate 1, the movable frame 21 provided between the support substrate 1 and the lid 2, the first comb-teeth movable electrode 22a and/or the second comb-teeth movable electrode 22b as the comb-teeth movable electrode provided in the movable frame 21, and the protrusion 31 and/or the protrusion 30 provided on at least one of the support substrate 1 or the lid 2 and overlapping the tip end or the base part of the first comb-teeth movable electrode 22a and/or the second comb-teeth movable electrode 22b in a plan view.
As described above, the protrusion 31 and/or the protrusion 30 is provided which overlaps the tip end or the base part of the first comb-teeth movable electrode 22a and/or the second comb-teeth movable electrode 22b in a plan view. Therefore, even when an excessive acceleration is applied to the inertial sensor 100, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth movable electrode 22a and/or the second comb-teeth movable electrode 22b.
Therefore, a highly reliable inertial sensor 100 can be realized by suppressing the occurrence of cracks or chips in the MEMS structure that causes a failure.
The inertial sensor 100 according to the present embodiment further includes the first fixed frame 11a and/or the second fixed frame 11b as the fixed frame provided between the support substrate 1 and the lid 2, and, as the comb-teeth fixed electrode, the first comb-teeth fixed electrode 12a provided in the first fixed frame 11a and/or the second comb-teeth fixed electrode 12b provided in the second fixed frame 11b, in which the protrusion 31 and/or the protrusion 30 overlaps the first comb-teeth fixed electrode 12a and/or the second comb-teeth fixed electrode 12b in a plan view.
As described above, the protrusion 31 and/or the protrusion 30 is provided which overlaps the first comb-teeth fixed electrode 12a and/or the second comb-teeth fixed electrode 12b in a plan view. Therefore, even when an excessive acceleration is applied to the inertial sensor 100, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth fixed electrode 12a and/or the second comb-teeth fixed electrode 12b.
Further, in the inertial sensor 100 according to the present embodiment, the protrusion 31 or the protrusion 30 overlaps the joint part of the first comb-teeth movable electrode 22a and/or the second comb-teeth movable electrode 22b and the movable frame 21 in a plan view.
As described above, the protrusion 31 and/or the protrusion 30 overlaps the joint part of the first comb-teeth movable electrode 22a and the movable frame 21 and/or the joint part of the second comb-teeth movable electrode 22b and the movable frame 21 in a plan view. Therefore, even when an excessive acceleration is applied to the inertial sensor 100, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth movable electrode 22a, the second comb-teeth movable electrode 22b, and/or the movable frame 21.
Further, in the inertial sensor 100 according to the present embodiment, the protrusion 31 and/or the protrusion 30 overlaps the base part of the first comb-teeth movable electrode 22a and/or the second comb-teeth movable electrode 22b in a plan view.
As described above, the protrusion 31 and/or the protrusion 30 overlaps the base part of the first comb-teeth movable electrode 22a and/or the base part of the second comb-teeth movable electrode 22b in a plan view. Therefore, even when an excessive acceleration is applied to the inertial sensor 100, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth movable electrode 22a, the second comb-teeth movable electrode 22b, and/or the movable frame 21.
Further, in the inertial sensor 100 according to the present embodiment, the protrusion 31 and/or the protrusion 30 overlaps the tip end of the first comb-teeth movable electrode 22a and/or the second comb-teeth movable electrode 22b in a plan view.
As described above, the protrusion 31 and/or the protrusion 30 overlaps the tip end of the first comb-teeth movable electrode 22a and/or the tip end of the second comb-teeth movable electrode 22b in a plan view. Therefore, even when an excessive acceleration is applied to the inertial sensor 100, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth movable electrode 22a, the second comb-teeth movable electrode 22b, and/or the movable frame 21.
Further, in the inertial sensor 100 according to the present embodiment, the protrusion 31 or the protrusion 30 overlaps from the base part to the tip end of the first comb-teeth movable electrode 22a and/or the second comb-teeth movable electrode 22b and the base part of the first comb-teeth fixed electrode 12a and/or the second comb-teeth fixed electrode 12b in a plan view.
As described above, the protrusion 31 and/or the protrusion 30 overlaps from the base part to the tip end of the first comb-teeth movable electrode 22a and/or the second comb-teeth movable electrode 22b and from the base part to the tip end of the first comb-teeth fixed electrode 12a and/or the second comb-teeth fixed electrode 12b in a plan view. Therefore, even when an excessive acceleration is applied to the inertial sensor 100, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth movable electrode 22a, the second comb-teeth movable electrode 12b, the first comb-teeth fixed electrode 12a, and/or the second comb-teeth fixed electrode 12b.
The inertial sensor 100 according to the present embodiment further includes the beam 27 as the spring that holds the movable frame 21, and the fixing area 25 that fixes the movable frame 21 to the support substrate 1 via the beam 27, in which the movable frame 21 has the first extension 21a that has one end coupled to one end of the beam 27, the second extension 21b that has one end coupled to the other end of the beam 27, and the coupler 21c that couples the other end of the first extension 21a to the other end of the second extension 21b, and the first comb-teeth movable electrode 22a and the second comb-teeth movable electrode 22b are provided in the coupler 21c.
As described above, the first comb-teeth movable electrode 22a and the second comb-teeth movable electrode 22b are provided in the coupler 21c of the movable frame 21. Therefore, even when an excessive acceleration is applied to the inertial sensor 100, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth movable electrode 22a and/or the second comb-teeth movable electrode 22b.
A schematic configuration of an inertial sensor 200 according to Embodiment 2 will be described with reference to
The inertial sensor 200 is a physical amount sensor that detects a change in physical amount due to displacement of a rectangular frame-shaped movable frame 212 as a change in capacitance. In the present embodiment, the inertial sensor 200 is an acceleration sensor that measures an acceleration in the Y-axis direction based on the displacement of the movable frame 212.
As illustrated in
The support substrate 102 has a cavity 102c including a recess, and a first mount 162a, a second mount 162b, a mount 44, and protrusions 312, 322, 332, and 372 are provided in the cavity 102c.
In the present embodiment, the support substrate 102 is made of a silicon substrate and can be formed by patterning the silicon substrate. A glass substrate or a ceramic substrate can also be used for the support substrate 102.
The lid 202 has a cavity 202c including a recess, and a protrusion 392 is provided in the cavity 202c.
In the present embodiment, the lid 202 is made of a glass substrate and can be formed by patterning the glass substrate. A silicon substrate or a ceramic substrate can also be used for the lid 202.
The element 302 is provided in an accommodation space S including the cavity 102c and the cavity 202c.
The element 302 is made of, for example, a silicon substrate doped with impurities, such as phosphorus or boron, and can be formed by patterning the silicon substrate.
The element 302 includes a movable electrode and a fixed electrode.
The movable electrode includes the movable frame 212, a first comb-teeth movable electrode 222a, a second comb-teeth movable electrode 222b, a third comb-teeth movable electrode 222c, a fourth comb-teeth movable electrode 222d, a first spring 282a, a second spring 282b, a first fixing area 252a, a second fixing area 252b, a conductor 42, and wirings 51a and 51b. These portions are integrally formed and electrically coupled to each other.
The conductor 42 is bonded to the upper surface of the mount 44. The first fixing area 252a is bonded to the upper surface of the first mount 162a. The second fixing area 252b is bonded to the upper surface of the second mount 162b.
The movable frame 212 is held swingably along the Y-axis direction by the first spring 282a and the second spring 282b. The movable frame 212 has a quadrangular border 212F in a plan view.
The border 212F includes a first side 212a, a second side 212b, a third side 212c, and a fourth side 212d. The first spring 282a is provided between the first side 212a and the first fixing area 252a of the border 212F. Further, the second spring 282b is provided between the third side 212c and the second fixing area 252b of the border 212F.
Each of the first comb-teeth movable electrode 222a, the second comb-teeth movable electrode 222b, the third comb-teeth movable electrode 222c, and the fourth comb-teeth movable electrode 222d has a movable electrode arm 232 and a movable electrode finger 242.
In the first comb-teeth movable electrode 222a, the movable electrode arm 232 is provided to extend from the second side 212b of the border 212F toward the + side of the X-axis direction. Further, the movable electrode finger 242 is provided to extend from the movable electrode arm 232 toward the + side in the Y-axis direction.
In the second comb-teeth movable electrode 222b, the movable electrode arm 232 is provided to extend from the fourth side 212d of the border 212F toward the-side in the X-axis direction. Further, the movable electrode finger 242 is provided to extend from the movable electrode arm 232 toward the-side in the Y-axis direction.
In the third comb-teeth movable electrode 222c, the movable electrode arm 232 is provided to extend from the second side 212b of the border 212F toward the + side in the X-axis direction. Further, the movable electrode finger 242 is provided to extend from the movable electrode arm 232 toward the + side in the Y-axis direction.
In the fourth comb-teeth movable electrode 222d, the movable electrode arm 232 is provided to extend from the fourth side 212d of the border 212F toward the-side in the X-axis direction. Further, the movable electrode finger 242 is provided to extend from the movable electrode arm 232 toward the-side in the Y-axis direction.
The fixed electrode includes a first fixed frame 112a, a second fixed frame 112b, a third fixed frame 112c, a fourth fixed frame 112d, a first comb-teeth fixed electrode 122a, a second comb-teeth fixed electrode 122b, a third comb-teeth fixed electrode 122c, a fourth comb-teeth fixed electrode 122d, conductors 41a and 41b, and wirings 52a, 52b, 52c, and 52d.
The conductors 41a and 41b are bonded to the upper surface of the mount 44. The first fixed frame 112a and the second fixed frame 112b are bonded to the upper surface of the first mount 162a. The third fixed frame 112c and the fourth fixed frame 112d are bonded to the upper surface of the second mount 162b.
Each of the first comb-teeth fixed electrode 122a, the second comb-teeth fixed electrode 122b, the third comb-teeth fixed electrode 122c, and the fourth comb-teeth fixed electrode 122d has a fixed electrode arm 132 and a fixed electrode finger 142.
The fixed electrode arm 132 of the first comb-teeth fixed electrode 122a faces the movable electrode arm 232 of the first comb-teeth movable electrode 222a with a predetermined gap in the Y-axis direction. Further, in the first comb-teeth fixed electrode 122a, the fixed electrode finger 142 provided on the fixed electrode arm 132 faces the movable electrode finger 242 of the first comb-teeth movable electrode 222a with a predetermined gap in the X-axis direction.
The fixed electrode arm 132 of the second comb-teeth fixed electrode 122b faces the movable electrode arm 232 of the second comb-teeth movable electrode 222b with a predetermined gap in the Y-axis direction. Further, in the second comb-teeth fixed electrode 122b, the fixed electrode finger 142 provided on the fixed electrode arm 132 faces the movable electrode finger 242 of the second comb-teeth movable electrode 222b with a predetermined gap in the X-axis direction.
The fixed electrode arm 132 of the third comb-teeth fixed electrode 122c faces the movable electrode arm 232 of the third comb-teeth movable electrode 222c with a predetermined gap in the Y-axis direction. Further, in the third comb-teeth fixed electrode 122c, the fixed electrode finger 142 provided on the fixed electrode arm 132 faces the movable electrode finger 242 of the third comb-teeth movable electrode 222c with a predetermined gap in the X-axis direction.
The fixed electrode arm 132 of the fourth comb-teeth fixed electrode 122d faces the movable electrode arm 232 of the fourth comb-teeth movable electrode 222d with a predetermined gap in the Y-axis direction. Further, in the fourth comb-teeth fixed electrode 122d, the fixed electrode finger 142 provided on the fixed electrode arm 132 faces the movable electrode finger 242 of the fourth comb-teeth movable electrode 222d with a predetermined gap in the X-axis direction.
The support substrate 102 has protrusions 312, 322, 332, and 372. Further, the lid 202 has the protrusion 392. Although not illustrated, the plan shape of the protrusion 392 is substantially the same as the protrusions 312, 322, 332, and 372 facing in the Z-axis direction.
All the protrusions 312, 322, 332, 372, and 392 are stoppers for suppressing the significant vibration of the first comb-teeth movable electrode 222a, the second comb-teeth movable electrode 222b, the third comb-teeth movable electrode 222c, the fourth comb-teeth movable electrode 222d, the first comb-teeth fixed electrode 122a, the second comb-teeth fixed electrode 122b, the third comb-teeth fixed electrode 122c, and/or the fourth comb-teeth fixed electrode 122d.
In order to cause the protrusions 312, 322, 332, 372, and 392 to function as the stoppers, the protrusions 312, 322, 332, 372, and 392 are disposed at positions overlapping the first comb-teeth movable electrode 222a, the second comb-teeth movable electrode 222b, the third comb-teeth movable electrode 222c, the fourth comb-teeth movable electrode 222d, the first comb-teeth fixed electrode 122a, the second comb-teeth fixed electrode 122b, the third comb-teeth fixed electrode 122c, and/or the fourth comb-teeth fixed electrode 122d in a plan view.
In the present embodiment, the disposition positions of the protrusions 312, 322, 332, and 372 are different from each other to explain the variations in the disposition positions. However, all the disposition positions of the protrusions 312, 322, 332, and 372 may be the same or some of them are the same and the other may be different.
The protrusion 312 and the protrusion 392 facing the protrusion 312 overlap the first comb-teeth movable electrode 222a and the first comb-teeth fixed electrode 122a in a plan view. The protrusion 312 and the protrusion 392 facing the protrusion 312 overlap the base part of the movable electrode finger 242 of the first comb-teeth movable electrode 222a and the tip end of the fixed electrode finger 142 of the first comb-teeth fixed electrode 122a in a plan view.
The protrusion 322 and the protrusion 392 facing the protrusion 322 overlap the second comb-teeth movable electrode 222b and the second comb-teeth fixed electrode 122b in a plan view. The protrusion 322 and the protrusion 392 facing the protrusion 322 overlap the base part of the movable electrode finger 242 of the second comb-teeth movable electrode 222b and the tip end of the fixed electrode finger 142 of the second comb-teeth fixed electrode 122b in a plan view.
The protrusion 332 and the protrusion 392 facing the protrusion 332 overlap the third comb-teeth movable electrode 222c and the third comb-teeth fixed electrode 122c in a plan view. The protrusion 332 and the protrusion 392 facing the protrusion 332 overlap the tip end of the movable electrode finger 242 of the third comb-teeth movable electrode 222c and the base part of the fixed electrode finger 142 of the third comb-teeth fixed electrode 122c and the joint part of the fixed electrode finger 142 and the fixed electrode arm 132 in a plan view.
The protrusion 372 and the protrusion 392 facing the protrusion 372 overlap the fourth comb-teeth movable electrode 222d and the fourth comb-teeth fixed electrode 122d in a plan view. The protrusion 372 and the protrusion 392 facing the protrusion 372 overlap from the joint part of the movable electrode finger 242 and the movable electrode arm 232 of the fourth comb-teeth movable electrode 222d to the joint part of the fixed electrode finger 142 and the fixed electrode arm 132 of the fourth comb-teeth fixed electrode 122d in a plan view.
In the present embodiment, the protrusions 312, 322, 332, 372, and the protrusion 392 are disposed at overlapping positions in a plan view, but the protrusions 312, 322, 332, and 372 and the protrusion 392 may be disposed at positions not overlapping each other in a plan view.
Further, instead of the protrusions 312, 322, 332, 372, and 392, protrusions illustrated in other embodiments may be adopted.
When an excessive acceleration is applied to the inertial sensor 200, the first comb-teeth movable electrode 222a, the second comb-teeth movable electrode 222b, the third comb-teeth movable electrode 222c, the fourth comb-teeth movable electrode 222d, the first comb-teeth fixed electrode 122a, the second comb-teeth fixed electrode 122b, the third comb-teeth fixed electrode 122c, and the fourth comb-teeth fixed electrode 122d come into contact with the protrusion 312, the protrusion 322, the protrusion 332, the protrusion 372 or the protrusion 392 before the vibration width in the Z-axis direction becomes excessively large.
In the present embodiment, the movable electrode arm 232, the movable electrode finger 242, the fixed electrode arm 132, or the fixed electrode finger 142 comes into contact with the protrusion 312, the protrusion 322, the protrusion 332, the protrusion 372, or the protrusion 392.
In other words, the movable electrode arm 232, the movable electrode finger 242, the fixed electrode arm 132, and/or the fixed electrode finger 142 is limited by the protrusion 312, the protrusion 322, the protrusion 332, the protrusion 372, or the protrusion 392 so that the vibration width does not become excessively large.
Therefore, the inertial sensor 200 according to the present embodiment includes the protrusion 312, the protrusion 322, the protrusion 332, the protrusion 372, and/or the protrusion 392. Therefore, even when an excessive acceleration is applied to the inertial sensor 200, the occurrence of cracks or chips can be suppressed or avoided in the movable electrode arm 232, the movable electrode finger 242, the fixed electrode arm 132, and/or the fixed electrode finger 142.
Further, when the protrusion 312, the protrusion 322, the protrusion 332, and/or the protrusion 372 suppresses the movable electrode arm 232, the movable electrode finger 242, the fixed electrode arm 132, and/or the fixed electrode finger 142 from coming into contact with or colliding with the bottom surface of the cavity 102c. Further, the protrusion 392 suppresses the movable electrode arm 232, the movable electrode finger 242, the fixed electrode arm 132, and/or the fixed electrode finger 142 from coming into contact with or colliding with the bottom surface of the cavity 202c.
In other words, the movable electrode arm 232, the movable electrode finger 242, the fixed electrode arm 132, and/or the fixed electrode finger 142 is protected so as not to come into contact with or collide with the bottom surface of the cavity 102c by the protrusion 312, the protrusion 322, the protrusion 332, and/or the protrusion 372. Further, the movable electrode arm 232, the movable electrode finger 242, the fixed electrode arm 132, and/or the fixed electrode finger 142 is protected so as not to come into contact with or collide with the bottom surface of the cavity 202c by the protrusion 392.
Therefore, the inertial sensor 200 according to the present embodiment includes the protrusion 312, the protrusion 322, the protrusion 332, the protrusion 372, and/or the protrusion 392. Therefore, even when an excessive acceleration is applied to the inertial sensor 200, the occurrence of cracks or chips can be suppressed in the movable electrode arm 232, the movable electrode finger 242, the fixed electrode arm 132, and/or the fixed electrode finger 142.
Further, the protrusion 312, the protrusion 322, the protrusion 332, the protrusion 372, and/or the protrusion 392 has an effect of suppressing the movable electrode arm 232, the movable electrode finger 242, the fixed electrode arm 132, and/or the fixed electrode finger 142 from adhering to the support substrate 102 or the lid 202.
A detector includes a first detector having the first comb-teeth movable electrode 222a and the first comb-teeth fixed electrode 122a, and a second detector having the second comb-teeth movable electrode 222b and the second comb-teeth fixed electrode 122b, a third detector having the third comb-teeth movable electrode 222c and the third comb-teeth fixed electrode 122c, and a fourth detector having the fourth comb-teeth movable electrode 222d and the fourth comb-teeth fixed electrode 122d.
Each of the first detector, the second detector, the third detector, and the fourth detector detects the acceleration in the Y-axis direction.
In the inertial sensor 200, when an acceleration on the-side in the Y-axis direction occurs, the gap between the movable electrode arm 232 and the fixed electrode arm 132 decreases and the facing area between the movable electrode finger 242 and the fixed electrode finger 142 increases in the first detector and the third detector, and the gap between the movable electrode arm 232 and the fixed electrode arm 132 increases and the facing area between the movable electrode finger 242 and the fixed electrode finger 142 is reduced in the second detector and the fourth detector.
Further, when the acceleration on the + side in the Y-axis direction occurs, the gap between the movable electrode arm 232 and the fixed electrode arm 132 increases and the facing area between the movable electrode finger 242 and the fixed electrode finger 142 is reduced in the first detector and the third detector, and the gap between the movable electrode arm 232 and the fixed electrode arm 132 decreases and the facing area between the movable electrode finger 242 and the fixed electrode finger 142 increases in the second detector and the fourth detector.
Therefore, the inertial sensor 200 according to the present embodiment can detect the acceleration on the + side in the Y-axis direction and the acceleration on the-side in the Y-axis direction by detecting the increase or reduction in the facing areas in the first detector and the third detector and the reduction or increase in the facing areas between the second detector and the fourth detector, as the change in capacitance. In addition, the acceleration on the + side in the Y-axis direction and the acceleration on the-side in the Y-axis direction can be detected by detecting reduction or expansion of the gap between the first detector and the third detector and expansion or reduction of the gap between the second detector and the fourth detector, as the change in capacitance.
In the present embodiment, description is made such that the first comb-teeth movable electrode 222a, the second comb-teeth movable electrode 222b, the third comb-teeth movable electrode 222c, and the fourth comb-teeth movable electrode 222d include the movable electrode arm 232 and the movable electrode finger 242, and the first comb-teeth fixed electrode 122a, the second comb-teeth fixed electrode 122b, the third comb-teeth fixed electrode 122c, and the fourth comb-teeth fixed electrode 122d include the fixed electrode arm 132 and the fixed electrode finger 142.
However, it may be read that the movable electrode arm 232 is included in the movable frame 212, and only the movable electrode finger 242 corresponds to the first comb-teeth movable electrode 222a, the second comb-teeth movable electrode 222b, the third comb-teeth movable electrode 222c, and the fourth comb-teeth movable electrode 222d. Further, it may be read that the fixed electrode arm 132 is included in the first fixed frame 112a, the second fixed frame 112b, the third fixed frame 112c, and the fourth fixed frame 112d, and only the fixed electrode finger 142 corresponds to the first comb-teeth fixed electrode. 122a, the second comb-teeth fixed electrode 122b, the third comb-teeth fixed electrode 122c, and the fourth comb-teeth fixed electrode 122d.
By being read in this way, in the present embodiment, the disposition relationship between each protrusion and each electrode can be considered to be the same as the disposition in Embodiment 1.
That is, in the present embodiment, the joint part is a part at which the movable electrode finger 242 is coupled to the movable electrode arm 232. More specifically, when a joint is an end of the movable electrode finger 242 on the fixed end side, the joint part includes the joint and the peripheral part thereof. Further, in the present embodiment, the tip end is an end of the movable electrode finger 242 on the free end side, and the base part is a part close to the joint of the movable electrode finger 242 in the movable electrode finger 242. Further, the joint part is a part at which the fixed electrode finger 142 is coupled to the fixed electrode arm 132. More specifically, when a joint is an end of the fixed electrode finger 142 on the fixed end side, the joint part includes the joint and the peripheral part thereof. Further, in the present embodiment, the tip end is an end of the fixed electrode finger 142 on the free end side, and the base part is, for example, a part close to the joint of the fixed electrode finger 142 in the fixed electrode finger 142.
Hereinbefore, as described above, according to the inertial sensor 200 according to the present embodiment, the following effects can be obtained.
The inertial sensor 200 according to the present embodiment includes the support substrate 102, the lid 202 provided to face the support substrate 102, the movable frame 212 provided between the support substrate 102 and the lid 202, the first comb-teeth movable electrode 222a, the second comb-teeth movable electrode 222b, the third comb-teeth movable electrode 222c, or the fourth comb-teeth movable electrode 222d provided in the movable frame 212, and the protrusion 312, the protrusion 322, the protrusion 332, or the protrusion 372 provided at least one of the support substrate 102 or the lid 202 and overlapping the tip end or base part of the first comb-teeth movable electrode 222a, the second comb-teeth movable electrode 222b, the third comb-teeth movable electrode 222c, or the fourth comb-teeth movable electrode 222d in a plan view.
As described above, the protrusion 312, the protrusion 322, the protrusion 332, or the protrusion 372 are included which overlaps the tip end or the base part of the first comb-teeth movable electrode 222a, the second comb-teeth movable electrode 222b, the third comb-teeth movable electrode 222c, or the fourth comb-teeth movable electrode 222d in a plan view. Therefore, even when an excessive acceleration is applied to the inertial sensor 200, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth movable electrode 222a, the second comb-teeth movable electrode 222b, the third comb-teeth movable electrode 222c or the fourth comb-teeth movable electrode 222d.
Therefore, a highly reliable inertial sensor 200 can be realized by suppressing the occurrence of cracks or chips in the MEMS structure that causes a failure.
The inertial sensor 200 according to the present embodiment further includes the first fixed frame 112a provided between the support substrate 102 and the lid 202, and the first comb-teeth fixed electrode 122a provided in the first fixed frame 112a, in which the protrusion 312 overlaps the first comb-teeth fixed electrode 122a in a plan view.
As described above, the protrusion 312 overlaps the first comb-teeth fixed electrode 122a in a plan view. Therefore, even when an excessive acceleration is applied to the inertial sensor 200, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth fixed electrode 122a or the first fixed frame 112a.
Further, in the inertial sensor 200 according to the present embodiment, the first comb-teeth movable electrode 222a, the second comb-teeth movable electrode 222b, the third comb-teeth movable electrode 222c, and the fourth comb-teeth movable electrode 222d include the movable electrode arm 232 extending in the first direction, and the movable electrode finger 242 extending, from the movable electrode arm 232, in the Y-axis direction as the second direction intersecting the X-axis direction as the first direction, in which the protrusion 312 is provided along the X-axis direction.
As described above, the extending direction of the movable electrode arm 232 is the same as the extending direction of the protrusion 312. Therefore, the occurrence of cracks or chips can be suppressed or avoided in the movable electrode arm 232 and/or the movable electrode finger 242.
In the inertial sensor 200 according to the present embodiment, the protrusion 312 overlaps the joint part of the movable electrode arm 232 and the movable electrode finger 242 in a plan view.
As described above, the protrusion 312 overlaps the joint part of the movable electrode arm 232 and the movable electrode finger 242 in a plan view. Therefore, the occurrence of cracks or chips can be suppressed or avoided in the movable electrode arm 232 and/or the movable electrode finger 242.
In the inertial sensor 200 according to the present embodiment, the protrusion 322 overlaps the base part of the movable electrode finger 242 in a plan view.
As described above, the protrusion 322 overlaps the base part of the movable electrode finger 242 in a plan view. Therefore, the occurrence of cracks or chips can be suppressed or avoided in the movable electrode finger 242.
In the inertial sensor 200 according to the present embodiment, the protrusion 332 overlaps the tip end of the movable electrode finger 242 in a plan view.
As described above, the protrusion 332 overlaps the tip end of the movable electrode finger 242 in a plan view. Therefore, the occurrence of cracks or chips can be suppressed or avoided in the movable electrode finger 242.
The inertial sensor 200 according to the present embodiment includes the fourth fixed frame 112d provided between the support substrate 102 and the lid 202, and the fourth comb-teeth fixed electrode 122d provided in the fourth fixed frame 112d, in which the fourth comb-teeth fixed electrode 122d has a fixed electrode arm 132 facing the movable electrode arm 232, and a fixed electrode finger 142 extending from the fixed electrode arm 132 in the Y-axis direction as the second direction, and the protrusion 372 overlaps from the base part to the tip end of the movable electrode finger 242 and the base part to the tip end of the fixed electrode finger 142 in a plan view.
As described above, the protrusion 372 overlaps from the base part to the tip end of the movable electrode finger 242 and from the base part to the tip end of the fixed electrode finger 142 in a plan view. Therefore, the occurrence of cracks or chips can be suppressed or avoided in the movable electrode finger 242 and/or the fixed electrode finger 142.
The inertial sensor 200 according to the present embodiment further includes the first spring 282a that holds the movable frame 212, and the first fixing area 252a that fixes the movable frame 212 to the support substrate 102 via the first spring 282a, in which the movable frame 212 has the border 212F that surrounds the first comb-teeth movable electrode 222a, the first spring 282a is coupled to the first side 212a of the border 212F, and the first comb-teeth movable electrode 222a is provided on the second side 212b that intersects the first side 212a.
As described above, the first comb-teeth movable electrode 222a is provided in the movable frame 212. Therefore, even when an excessive acceleration is applied to the inertial sensor 200, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth movable electrode 222a.
A schematic configuration of an inertial sensor 300 according to Embodiment 3 will be described with reference to
The inertial sensor 300 is a physical amount sensor that detects a change in physical amount due to the displacement of a frame-shaped movable frame 213 as a change in capacitance. In the present embodiment, the inertial sensor 300 is an acceleration sensor that measures an acceleration in the X-axis direction based on the displacement of the movable frame 213.
As illustrated in
The support substrate 103 has a cavity 103c including a recess, and a mount 163 and protrusions 313a and 313b are provided in the cavity 103c.
In the present embodiment, the support substrate 103 is made of a silicon substrate and can be formed by patterning the silicon substrate. A glass substrate or a ceramic substrate can also be used for the support substrate 103.
The lid 203 has a cavity 203c including a recess, and protrusions 393a and 393b are provided in the cavity 203c.
In the present embodiment, the lid 203 is made of a glass substrate and can be formed by patterning the glass substrate. A silicon substrate or a ceramic substrate can also be used for the lid 203.
The element 303 is provided in an accommodation space S including the cavity 103c and the cavity 203c.
The element 303 is made of, for example, a silicon substrate doped with impurities, such as phosphorus and boron, and can be formed by patterning the silicon substrate.
The element 303 includes a movable electrode and a fixed electrode.
The movable electrode includes the movable frame 213, a first comb-teeth movable electrode 223a, a second comb-teeth movable electrode 223b, a third comb-teeth movable electrode 223c, a fourth comb-teeth movable electrode 223d, a first spring 283a, a second spring 283b, and a fixing area 253. These portions are integrally formed and electrically coupled to each other.
The fixing area 253 is bonded to the upper surface of the mount 163. The fixing area 253 has a part that extends from the mount 163 along a center line L1.
The movable frame 213 and the fixing area 253 are coupled to each other via the first spring 283a and the second spring 283b. Accordingly, the movable frame 213 is provided to be swingable in the X-axis direction.
The movable frame 213 has a quadrangular border 213F in a plan view.
The border 213F includes a first side 213a, a second side 213b, a third side 213c, a fourth side 213d, a first extension 213e, and a second extension 213f.
The first spring 283a is provided between the first side 213a of the border 213F and the fixing area 253. Further, the second spring 283b is provided between the third side 213c of the border 213F and the fixing area 253.
A plurality of first comb-teeth movable electrodes 223a is provided on the second side 213b of the border 213F. Each of the plurality of first comb-teeth movable electrodes 223a is provided to extend from the second side 213b toward the-side in the Y-axis direction. The length of each of the plurality of first comb-teeth movable electrodes 223a in the Y-axis direction gradually decreases toward the + side in the X-axis direction.
A plurality of second comb-teeth movable electrodes 223b are provided on the first extension 213e of the border 213F. Each of the plurality of second comb-teeth movable electrodes 223b is provided to extend from the first extension 213e toward the + side in the Y-axis direction. The length of each of the plurality of second comb-teeth movable electrodes 223b in the Y-axis direction gradually increases toward the + side in the X-axis direction.
A plurality of third comb-teeth movable electrodes 223c is provided on the second extension 213f of the border 213F. Each of the plurality of third comb-teeth movable electrodes 223c is provided to extend from the second extension 213f toward the-side in the Y-axis direction. The length of each of the plurality of third comb-teeth movable electrodes 223c in the Y-axis direction gradually increases toward the + side in the X-axis direction.
A plurality of fourth comb-teeth movable electrodes 223d is provided on the fourth side 213d of the border 213F. Each of the plurality of fourth comb-teeth movable electrodes 223d is provided to extend from the fourth side 213d toward the + side in the Y-axis direction. The length of each of the plurality of fourth comb-teeth movable electrodes 223d in the Y-axis direction gradually decreases toward the + side in the X-axis direction.
The fixed electrode includes a first fixed frame 113a, a second fixed frame 113b, a first comb-teeth fixed electrode 123a, a second comb-teeth fixed electrode 123b, a third comb-teeth fixed electrode 123c, and a fourth comb-teeth fixed electrode 123d.
Each of one ends of the first fixed frame 113a and the second fixed frame 113b is bonded to the upper surface of the mount 163.
Each of the other ends of the first fixed frame 113a and the second fixed frame 113b has an elongated rod shape. The other ends of the first fixed frame 113a and the second fixed frame 113b extend in a direction inclined with respect to the X axis and the Y axis, respectively, in a plan view.
Specifically, the center line L2 of the first fixed frame 113a and the center line L3 of the second fixed frame 113b are inclined toward the tip end side thereof so that the separation distance from the center line L1 increases.
Although the inclination of the first fixed frame 113a and the second fixed frame 113b with respect to the center line L1 is not particularly limited, the inclination is preferably 10° or more and 45° or less, and more preferably 10° or more and 30° or less. Thereby, the first comb-teeth fixed electrode 123a, the second comb-teeth fixed electrode 123b, the third comb-teeth fixed electrode 123c, and the fourth comb-teeth fixed electrode 123d can be suppressed from extending in the Y-axis direction, so that the size of the element 303 can be reduced.
The first comb-teeth fixed electrode 123a extends from the first fixed frame 113a to the + side in the Y-axis direction. Further, the first comb-teeth fixed electrode 123a faces the first comb-teeth movable electrode 223a with a predetermined gap.
The second comb-teeth fixed electrode 123b extends from the first fixed frame 113a to the-side in the Y-axis direction. Further, the second comb-teeth fixed electrode 123b faces the second comb-teeth movable electrode 223b with a predetermined gap.
The third comb-teeth fixed electrode 123c extends from the second fixed frame 113b to the + side in the Y-axis direction. Further, the third comb-teeth fixed electrode 123c faces the third comb-teeth movable electrode 223c with a predetermined gap.
The fourth comb-teeth fixed electrode 123d extends from the second fixed frame 113b to the-side in the Y-axis direction. Further, the fourth comb-teeth fixed electrode 123d faces the fourth comb-teeth movable electrode 223d with a predetermined gap.
The first comb-teeth fixed electrode 123a and the second comb-teeth fixed electrode 123b are electrically coupled to an electrode pad 63b via the first fixed frame 113a, a contact portion c2, and wiring 53b provided in a groove g2.
The third comb-teeth fixed electrode 123c and the fourth comb-teeth fixed electrode 123d are electrically coupled to an electrode pad 63c via the second fixed frame 113b, a contact portion c3, and wiring 53c provided in a groove g3.
The first comb-teeth movable electrode 223a, the second comb-teeth movable electrode 223b, the third comb-teeth movable electrode 223c, and the fourth comb-teeth movable electrode 223d are electrically coupled to the electrode pad 63a via the movable frame 213, the first spring 283a, the second spring 283b, the fixing area 253, the contact portion c1, and wiring 53a provided in the groove g1.
The support substrate 103 has the protrusions 313a and 313b. Further, the lid 203 includes protrusions 393a and 393b. Although not illustrated, the plan shapes of the protrusions 393a and 393b are substantially the same as the plan shapes of the protrusions 313a and 313b facing in the Z-axis direction.
All the protrusions 313a, 313b, 393a, and 393b are stoppers for suppressing the significant vibration of the first comb-teeth movable electrode 223a, the second comb-teeth movable electrode 223b, the third comb-teeth movable electrode 223c, the fourth comb-teeth movable electrode 223d, the first comb-teeth fixed electrode 123a, the second comb-teeth fixed electrode 123b, the third comb-teeth fixed electrode 122c, and/or the fourth comb-teeth fixed electrode 122d.
In order to cause the protrusions 313a, 313b, 393a, and 393b to function as the stoppers, the protrusion 313a and the protrusion 393a are disposed at positions overlapping the tip ends of the first comb-teeth movable electrode 223a and the second comb-teeth movable electrode 223b and the base parts and the joint part of the first comb-teeth fixed electrode 123a and the second comb-teeth fixed electrode 123b in a plan view. Further, the protrusion 313b and the protrusion 393b are disposed at positions overlapping the tip ends of the third comb-teeth movable electrode 223c and the fourth comb-teeth movable electrode 223d and the base parts and the joint part of the third comb-teeth fixed electrode 123c and the fourth comb-teeth fixed electrode 123d in a plan view.
In the present embodiment, the protrusion 313a and the protrusion 393a are disposed at positions overlapping each other in a plan view, but the protrusion 313a and the protrusion 393a may be disposed at positions not overlapping each other in a plan view. Further, the protrusion 313b and the protrusion 393b are disposed at positions overlapping each other in a plan view, but the protrusion 313b and the protrusion 393b may be disposed at positions not overlapping each other in a plan view.
Further, instead of the protrusions 313a, 313b, 393a, and 393b, protrusions illustrated in other embodiments may be adopted.
For example, the protrusion 313a and/or the protrusion 393a may be disposed at positions overlapping the base part and/or the joint part of the first comb-teeth movable electrode 223a.
Further, the protrusion 313a and/or the protrusion 393a may be disposed at positions overlapping the base part and/or the joint part of the second comb-teeth movable electrode 223b.
Further, the protrusion 313b and/or the protrusion 393b may be disposed at positions overlapping the base part and/or the joint part of the third comb-teeth movable electrode 223c.
Further, the protrusion 313b and/or the protrusion 393b may be disposed at positions overlapping the base part and/or the joint part of the fourth comb-teeth movable electrode 223d.
Further, the protrusions 313a and 393a may be disposed at positions overlapping from the joint part or the base part of the first comb-teeth movable electrode 223a to the joint part or the base part of the second comb-teeth movable electrode 223b.
Further, the protrusions 313b and 393b may be disposed at positions overlapping from the joint part or the base part of the third comb-teeth movable electrode 223c to the joint part or the base part of the fourth comb-teeth movable electrode 223d.
When an excessive acceleration is applied to the inertial sensor 300, the first comb-teeth movable electrode 223a, the second comb-teeth movable electrode 223b, the third comb-teeth movable electrode 223c, the fourth comb-teeth movable electrode 223d, the first comb-teeth fixed electrode 123a, the second comb-teeth fixed electrode 123b, the third comb-teeth fixed electrode 123c, or the fourth comb-teeth fixed electrode 123d comes into contact with the protrusion 313a, the protrusion 313b, the protrusion 393a, and/or the protrusion 393b before the vibration width in the Z-axis direction becomes excessively large.
Therefore, the inertial sensor 300 according to the present embodiment includes the protrusion 313a, the protrusion 313b, the protrusion 393a, and/or the protrusion 393b. Therefore, even when an excessive acceleration is applied to the inertial sensor 300, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth movable electrode 223a, the second comb-teeth movable electrode 223b, the third comb-teeth movable electrode 223c, the fourth comb-teeth movable electrode 223d, the first comb-teeth fixed electrode 123a, the second comb-teeth fixed electrode 123b, the third comb-teeth fixed electrode 123c, and/or the fourth comb-teeth fixed electrode 123d.
Further, the protrusion 313a suppresses the first comb-teeth movable electrode 223a, the second comb-teeth movable electrode 223b, the first comb-teeth fixed electrode 123a, and/or the second comb-teeth fixed electrode 123b from coming into contact with or colliding with the bottom surface of the cavity 103c. Further, the protrusion 393a suppresses the first comb-teeth movable electrode 223a, the second comb-teeth movable electrode 223b, the first comb-teeth fixed electrode 123a, and/or the second comb-teeth fixed electrode 123b from coming into contact with or colliding with the bottom surface of the cavity 203c.
In other words, the first comb-teeth movable electrode 223a, the second comb-teeth movable electrode 223b, the first comb-teeth fixed electrode 123a, and/or the second comb-teeth fixed electrode 123b is protected so as not to come into contact with or collide with the bottom surface of the cavity 103c by the protrusion 313a. Further, the first comb-teeth movable electrode 223a, the second comb-teeth movable electrode 223b, the first comb-teeth fixed electrode 123a, and/or the second comb-teeth fixed electrode 123b is protected so as not to come into contact with or collide with the bottom surface of the cavity 203c by the protrusion 393a.
Further, the protrusion 313b suppresses the third comb-teeth movable electrode 223c, the fourth comb-teeth movable electrode 223d, the third comb-teeth fixed electrode 123c, and/or the fourth comb-teeth fixed electrode 123d from coming into contact with or colliding with the bottom surface of the cavity 103c. Further, the protrusion 393b suppresses the third comb-teeth movable electrode 223c, the fourth comb-teeth movable electrode 223d, the third comb-teeth fixed electrode 123c, and/or the fourth comb-teeth fixed electrode 123d from coming into contact with or colliding with the bottom surface of the cavity 203c.
In other words, the third comb-teeth movable electrode 223c, the fourth comb-teeth movable electrode 223d, the third comb-teeth fixed electrode 123c, and/or the fourth comb-teeth fixed electrode 123d is protected so as not to come into contact with or collide with the bottom surface of the cavity 103c by the protrusion 313b. Further, the third comb-teeth movable electrode 223c, the fourth comb-teeth movable electrode 223d, the third comb-teeth fixed electrode 123c, and/or the fourth comb-teeth fixed electrode 123d is protected so as not to come into contact with or collide with the bottom surface of the cavity 203c by the protrusion 393b.
Therefore, the inertial sensor 300 according to the present embodiment includes the protrusion 313a, the protrusion 313b, the protrusion 393a, and/or the protrusion 393b. Therefore, even when an excessive acceleration is applied to the inertial sensor 300, the occurrence of cracks and chips can be suppressed in the first comb-teeth movable electrode 223a, the second comb-teeth movable electrode 223b, the third comb-teeth movable electrode 223c, the fourth comb-teeth movable electrode 223d, the first comb-teeth fixed electrode 123a, the second comb-teeth fixed electrode 123b, the third comb-teeth fixed electrode 123c, and/or the fourth comb-teeth fixed electrode 123d.
Further, the protrusion 313a, the protrusion 313b, the protrusion 393a, and/or the protrusion 393b has an effect of suppressing the first comb-teeth movable electrode 223a, the second comb-teeth movable electrode 223b, the third comb-teeth movable electrode 223c, the fourth comb-teeth movable electrode 223d, the first comb-teeth fixed electrode 123a, the second comb-teeth fixed electrode 123b, the third comb-teeth fixed electrode 123c, and/or the fourth comb-teeth fixed electrode 123d from adhering to the support substrate 103 or the lid 203.
A detector includes a first detector having the first comb-teeth movable electrode 223a, the first comb-teeth fixed electrode 123a, the second comb-teeth movable electrode 223b, and the second comb-teeth fixed electrode 123b, and a second detector having the third comb-teeth movable electrode 223c, the third comb-teeth fixed electrode 123c, the fourth comb-teeth movable electrode 223d and the fourth comb-teeth fixed electrode 123d. Each of the first detector and the second detector detects the acceleration in the X-axis direction.
In the inertial sensor 300, when the acceleration occurs on the-side in the X-axis direction, the gap between the first comb-teeth movable electrode 223a and the first comb-teeth fixed electrode 123a and the second comb-teeth movable electrode 223b and the second comb-teeth fixed electrode 123b increases in the first detector, and the gap between the third comb-teeth movable electrode 223c and the third comb-teeth fixed electrode 123c and the fourth comb-teeth movable electrode 223d and the fourth comb-teeth fixed electrode 123d decreases in the second detector.
Further, when the acceleration occurs on the + side in the X-axis direction, the gap between the first comb-teeth movable electrode 223a and the first comb-teeth fixed electrode 123a and the second comb-teeth movable electrode 223b and the second comb-teeth fixed electrode 123b decreases in the first detector, and the gap between the third comb-teeth movable electrode 223c and the third comb-teeth fixed electrode 123c and the fourth comb-teeth movable electrode 223d and the fourth comb-teeth fixed electrode 123d increases in the second detector.
Therefore, the inertial sensor 300 according to the present embodiment can detect the acceleration on the + side in the X-axis direction and the acceleration on the − side in the X-axis direction by detecting the expansion or reduction of the gap between the first detector and the reduction or expansion of the gap between the second detector as the change in capacitance.
Hereinbefore, as described above, according to the inertial sensor 300 according to the present embodiment, the following effects can be obtained.
The inertial sensor 300 according to the present embodiment includes the support substrate 103, the lid 203 provided to face the support substrate 103, the movable frame 213 provided between the support substrate 103 and the lid 203, the first comb-teeth movable electrode 223a provided in the movable frame 213, the protrusion 313a and/or the protrusion 393a provided on at least one of the support substrate 103 or the lid 203 and overlapping the tip end or the base part of the first comb-teeth movable electrode 223a in a plan view.
As described above, in a plan view, the protrusion 313a and/or the protrusion 393a is provided which overlaps the tip end or the base part of the first comb-teeth movable electrode 223a. Therefore, even when an excessive acceleration is applied to the inertial sensor 300, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth movable electrode 223a and/or the second comb-teeth movable electrode 223b.
Therefore, a highly reliable inertial sensor 300 can be realized by suppressing the occurrence of cracks or chips in the MEMS structure that causes a failure.
The inertial sensor 300 according to the present embodiment further includes the first fixed frame 113a provided between the support substrate 103 and the lid 203, and the first comb-teeth fixed electrode 123a provided in the first fixed frame 113a, in which the protrusion 313a and/or the protrusion 393a overlaps the first comb-teeth fixed electrode 123a in a plan view.
As described above, the protrusion 313a and/or the protrusion 393a is included which overlaps the first comb-teeth fixed electrode 123a in a plan view. Therefore, even when an excessive acceleration is applied to the inertial sensor 300, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth fixed electrode 123a.
Further, in the inertial sensor 300 according to the present embodiment, the protrusion 313a and/or the protrusion 393a overlaps the joint part of the first comb-teeth movable electrode 223a and the movable frame 213 in a plan view.
As described above, the protrusion 313a and/or the protrusion 393b overlaps the joint part of the first comb-teeth movable electrode 223a and the movable frame 213 in a plan view. Therefore, even when an excessive acceleration is applied to the inertial sensor 300, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth movable electrode 223a or the movable frame 213.
Further, in the inertial sensor 300 according to the present embodiment, the protrusion 313a overlaps the base part of the first comb-teeth movable electrode 223a in a plan view.
As described above, the protrusion 313a and/or the protrusion 393a overlaps the base part of the first comb-teeth movable electrode 223a in a plan view. Therefore, even when an excessive acceleration is applied to the inertial sensor 300, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth movable electrode 223a or the movable frame 213.
Further, in the inertial sensor 300 according to the present embodiment, the protrusion 313a and/or the protrusion 393a overlaps the tip end of the first comb-teeth movable electrode 223a in a plan view.
As described above, the protrusion 313a and/or the protrusion 393a overlaps the tip end of the first comb-teeth movable electrode 223a in a plan view. Therefore, even when an excessive acceleration is applied to the inertial sensor 300, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth movable electrode 223a or the movable frame 213.
Further, in the inertial sensor 300 according to the present embodiment, the protrusion 313a and/or the protrusion 393a overlaps from the base part to the tip end of the first comb-teeth movable electrode 223a and from the base part to the tip end of the first comb-teeth fixed electrode 123a in a plan view.
As described above, the protrusion 313a and/or the protrusion 393a overlaps from the base part to the tip end of the first comb-teeth movable electrode 223a and from the base part to the tip end of the first comb-teeth fixed electrode 123a in a plan view. Therefore, even when an excessive acceleration is applied to the inertial sensor 300, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth movable electrode 223a and/or the first comb-teeth fixed electrode 123a.
The inertial sensor 300 according to the present embodiment further includes the first spring 283a and the second spring 283b that hold the movable frame 213, and the fixing area 253 that fixes the movable frame 213 to the support substrate 103 via the first spring 283a and the second spring 283b, in which the movable frame 213 has the border 213F that surrounds the first comb-teeth movable electrode 223a, the first spring 283a is coupled to the first side 213a of the border 213F, and the first comb-teeth movable electrode 223a is provided on the second side 213b that intersects the first side 213a.
As described above, the first comb-teeth movable electrode 223a is provided in the movable frame 213.
Therefore, even when an excessive acceleration is applied to the inertial sensor 300, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth movable electrode 223a.
A schematic configuration of an inertial sensor 400 according to Embodiment 4 will be described with reference to
The inertial sensor 400 is a three-axis acceleration sensor that can independently detect the acceleration of the X axis, the Y axis, and the Z axis.
The inertial sensor 400 includes a support substrate 104, a lid 204 bonded to the support substrate 104, and an element 304x, an element 304y, and an element 304z that are provided between the support substrate 104 and the lid 204.
The support substrate 104 has cavities Cx, Cy, and Cz including a recess.
The mounts 162a, 162b, and 44 and protrusions 352 and 362 are provided in the cavity Cx and the cavity Cy, respectively.
Mounts 16 and 26 and the protrusions 31 and 32 are provided in the cavity Cz.
The support substrate 104 is made of a silicon substrate and can be formed by patterning the silicon substrate. The support substrate 104 may be a glass substrate or a ceramic substrate.
The lid 204 has cavities (not illustrated) corresponding to the cavities Cx, Cy, and Cz of the support substrate 104, respectively. Further, protrusions facing the protrusions 31, 32, 352, and 362 are provided in the cavities of the lid 204.
In the present embodiment, the lid 204 is made of a glass substrate and can be formed by patterning the glass substrate. The lid 204 may be a silicon substrate or a ceramic substrate.
In the present embodiment, the element has three elements including the element 304x, the element 304y, and the element 304z.
The element 304x detects the acceleration in the X-axis direction.
The element 304x has the same structure as the element 302 of Embodiment 2, and, in order to be able to detect the acceleration in the X-axis direction, the disposition directions of the comb-teeth movable electrode 222 and the comb-teeth fixed electrode 122 are rotated 90 degrees counterclockwise with respect to those in Embodiment 2.
The comb-teeth movable electrode 222 includes a movable electrode arm 232 and a movable electrode finger 242. Further, the comb-teeth fixed electrode 122 facing the comb-teeth movable electrode 222 includes a fixed electrode arm 132 and a fixed electrode finger 142.
The comb-teeth movable electrode 222 and the comb-teeth fixed electrode 122 overlap the protrusion 352 and the protrusion 362 in a plan view.
The protrusion 352 overlaps the joint part of the movable electrode arm 232 and the movable frame 212, the base part of the movable electrode arm 232, and the tip end of the fixed electrode arm 132.
The protrusion 362 overlaps the joint part of the fixed electrode arm 132 and the fixed frame 112, the base part of the fixed electrode arm 132, and the tip end of the movable electrode arm 232.
Instead of the protrusion 352 and/or the protrusion 362, those illustrated in other embodiments may be employed. For example, instead of the protrusion 352 and/or the protrusion 362, one or more of the protrusion 312, the protrusion 322, the protrusion 332, or the protrusion 372 described in Embodiment 2 may be employed.
The element 304y detects the acceleration in the Y-axis direction. The element 304y has the same structure as the element 302 of Embodiment 2.
The comb-teeth movable electrode 222 includes a movable electrode arm 232 and a movable electrode finger 242. Further, the comb-teeth fixed electrode 122 facing the comb-teeth movable electrode 222 includes a fixed electrode arm 132 and a fixed electrode finger 142.
The comb-teeth movable electrode 222 and the comb-teeth fixed electrode 122 overlap the protrusion 352 and the protrusion 362 in a plan view. Instead of the protrusion 352 and/or the protrusion 362, those illustrated in other embodiments may be employed. For example, instead of the protrusion 352 and/or the protrusion 362, one or more of the protrusion 312, the protrusion 322, the protrusion 332, or the protrusion 372 described in Embodiment 2 may be employed.
The element 304z detects an acceleration in the Z-axis direction. The element 304z has the same structure as the element 3 of Embodiment 1.
The first comb-teeth movable electrode 22a and the second comb-teeth movable electrode 22b, and the first comb-teeth fixed electrode 12a and the second comb-teeth fixed electrode 12b overlap the protrusions 31 and 32 in a plan view. Instead of the protrusion 31 and/or the protrusion 32, those illustrated in other embodiments may be employed. For example, instead of the protrusion 31 and/or the protrusion 32, one or a plurality of the protrusions 33, 34, 35, or 37 described in Embodiment 1 may be employed.
Hereinbefore, as described above, according to the inertial sensor 400 according to the present embodiment, the following effects can be obtained in addition to the effects of the above-described embodiments.
The inertial sensor 400 according to the present embodiment includes the support substrate 104, the lid 204 provided to face the support substrate 104, the movable frame 21 provided between the support substrate 104 and the lid 204, the first comb-teeth movable electrode 22a provided in the movable frame 21, and the protrusion 31 or the protrusion 32 provided on at least one of the support substrate 104 or the lid 204 and overlapping the tip end or the base part of the first comb-teeth movable electrode 22a in a plan view.
As described above, in a plan view, the protrusion 31 and/or the protrusion 32 is included which overlaps the tip end and/or the base part of the first comb-teeth movable electrode 22a. Therefore, even when an excessive acceleration is applied to the inertial sensor 400, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth movable electrode 22a.
Therefore, a highly reliable inertial sensor 400 can be realized by suppressing the occurrence of cracks or chips in the MEMS structure that causes a failure.
The inertial sensor 400 according to the present embodiment includes the support substrate 104, the lid 204 provided to face the support substrate 104, the movable frame 212 provided between the support substrate 104 and the lid 204, the comb-teeth movable electrode 222 provided in the movable frame 212, and the protrusion 352 or the protrusion 362 provided on at least one of the support substrate 104 or the lid 204 and overlapping the tip end or the base part of the comb-teeth movable electrode 222 in a plan view.
As described above, in a plan view, the protrusion 352 or the protrusion 362 is included which overlaps the tip end or the base part of the comb-teeth movable electrode 222. Therefore, even when an excessive acceleration is applied to the inertial sensor 400, the occurrence of cracks or chips can be suppressed or avoided in the comb-teeth movable electrode 222.
Therefore, a highly reliable inertial sensor 400 can be realized by suppressing the occurrence of cracks or chips in the MEMS structure that causes a failure.
The inertial sensor 400 according to the present embodiment further includes the beam 27 as the spring that holds the movable frame 21, and the fixing area 25 that fixes the movable frame 21 to the support substrate 104 via the beam 27, in which the movable frame 21 has the first extension 21a that has one end coupled to one end of the beam 27, the second extension 21b that has one end coupled to the other end of the beam 27, and the coupler 21c that couples the other end of the first extension 21a and the other end of the second extension 21b, and the first comb-teeth movable electrode 22a is provided in the coupler 21c.
As described above, the first comb-teeth movable electrode 22a is provided in the coupler 21c of the movable frame 21. Therefore, even when an excessive acceleration is applied to the inertial sensor 400, the occurrence of cracks or chips can be suppressed or avoided in the first comb-teeth movable electrode 22a.
The inertial sensor 400 according to the present embodiment further includes the first spring 282a that holds the movable frame 212, and the first fixing area 252a that fixes the movable frame 212 to the support substrate 104 via the first spring 282a, in which the movable frame 212 has the border 212F that surrounds the comb-teeth movable electrode 222, the first spring 282a is coupled to the first side 212a of the border 212F, and the comb-teeth movable electrode 222 is provided on the second side 212b that intersects the first side 212a.
As described above, the comb-teeth movable electrode 222 is provided in the movable frame 212. Therefore, even when an excessive acceleration is applied to the inertial sensor 400, the occurrence of cracks or chips can be suppressed or avoided in the comb-teeth movable electrode 222.
Next, an inertial measurement apparatus 5000 including the inertial sensor 100 will be described with reference to
The inertial measurement apparatus 5000 is used as an apparatus which is mounted on an attached apparatus, such as a vehicle, a robot, a smartphone, or a portable movement meter, to detect the posture, behavior, and the like of the attached apparatus.
As illustrated in
The outer case 501 is a box-shaped container having a rectangular parallelepiped outer shape without a lid. The material of the outer case 501 is, for example, aluminum. In addition, other metals, such as zinc and stainless steel, resins, or composites of metals and resins may be used.
The outer shape of the outer case 501 is a rectangular parallelepiped having a substantially square shape in a plan shape, and through-holes 502 are respectively formed in the vicinity of two vertices located in the diagonal direction of a square. The through-holes 502 are used when the inertial measurement apparatus 5000 is attached to an attached apparatus.
The sensor module 525 includes an inner case 520 and a circuit substrate 515.
The circuit substrate 515 is mounted with an acceleration detection unit 101 in which the inertial sensor 100 is incorporated, an external coupling connector 516, and the like.
The inner case 520 is a member that supports the circuit substrate 515, and has a shape that fits inside the outer case 501. As the material of the inner case 520, the same material as that of the outer case 501 can be used.
On the lower surface of the inner case 520, a recess 531 for preventing contact with the circuit substrate 515 and an opening 521 for exposing the connector 516 are formed.
With reference to
As illustrated in
The connector 516, the acceleration detection unit 101, angular velocity sensors 517x, 517y, and 517z, and the like are mounted on the upper surface and the side surface of the circuit substrate 515.
The acceleration detection unit 101 is an acceleration sensor which is mounted with the inertial sensor 100 to measure the acceleration in the Z-axis direction.
The connector 516 is a plug-type connector, and includes two rows of coupling terminals disposed at equal pitches in the X-axis direction. In the present embodiment, the coupling terminals corresponding to 10 pins in one row and 20 pins in total in two rows are included, but the number of coupling terminals may be appropriately changed according to design specifications.
The angular velocity sensor 517z is a gyro sensor that detects the angular velocity of one axis in the Z-axis direction. As a preferable example, a vibration gyro sensor is used that uses crystallized quartz as a vibrator and detects the angular velocity from Coriolis force applied to a vibrating object. In addition, the present disclosure is not limited to the vibration gyro sensor, and a sensor using ceramic or silicon as the vibrator may be used.
Further, on the side surface of the circuit substrate 515 in the X-axis direction, the angular velocity sensor 517x that detects the angular velocity of one axis in the X-axis direction is mounted so that the mounting surface is orthogonal to the X-axis. Similarly, on the side surface of the circuit substrate 515 in the Y-axis direction, an angular velocity sensor 517y that detects an angular velocity of one axis in the Y-axis direction is mounted so that a mounting surface is orthogonal to the Y-axis.
The angular velocity sensors 517x, 517y, and 517z are not limited to the configuration using the three angular velocity sensors for the X axis, the Y axis, and the Z axis, respectively, and may be sensors that can detect the angular velocities of the three axes. For example, a sensor device may be used which can detect the angular velocities of the three axes with one device or a package.
The acceleration detection unit 101 is an acceleration sensor for measuring the acceleration in the Z-axis direction, but may measure the acceleration in the X-axis direction or the Y-axis direction. Further, a plurality of inertial sensors 100 may be mounted to detect the acceleration, for example, in two-axis directions, such as the Z-axis direction and the Y-axis direction or the Z-axis direction and the X-axis direction, or in three-axis directions, such as the X-axis direction, the Y-axis direction, and the Z-axis direction.
A control IC 519 as a controller is mounted on the lower surface of the circuit substrate 515.
The control IC 519 is a micro controller unit (MCU), has a built-in storage including a non-volatile memory, an A/D converter, and the like, and controls each portion of the inertial measurement apparatus 5000. The storage stores a program that defines an order and content for detecting the acceleration and the angular velocity, a program that digitizes detected data and incorporates the detected data into packet data, accompanying data, and the like. A plurality of other electronic components are mounted on the circuit substrate 515 in addition to the above programs and data.
According to the inertial measurement apparatus 5000, since the acceleration detection unit 101 including the inertial sensor 100 is used, the inertial measurement apparatus 5000 can be provided which has excellent impact resistance and improved reliability.
As described above, according to the inertial measurement apparatus 5000 including the inertial sensor 100 according to the present embodiment, a highly reliable inertial measurement apparatus can be provided in addition to the effect of Embodiment 1.
In the present embodiment, the inertial measurement apparatus 5000 includes the inertial sensor 100, but the inertial measurement apparatus 5000 may include the inertial sensor 200, the inertial sensor 300, and/or the inertial sensor 400.
Hereinbefore, although the preferred embodiments are described, the present disclosure is not limited to the above-described embodiments. Further, the configuration of each portion of the present disclosure can be replaced with any configuration that exhibits the same functions as that of the above-described embodiments, or any configuration can be added.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-063289 | Apr 2023 | JP | national |
