JP7206905B2 - Inertial sensors, electronics and vehicles - Google Patents

Description

The present invention relates to inertial sensors, electronic devices, and moving bodies.

The angular velocity sensor described in Patent Document 1 includes a movable drive electrode, a fixed drive electrode that vibrates the movable drive electrode, a movable detection electrode that is connected to the movable drive electrode via a vibration amount amplifier, and a movable detection electrode. a fixed sensing electrode positioned opposite the electrode. In the angular velocity sensor having such a configuration, electrostatic attraction is generated between the movable drive electrode and the fixed drive electrode to vibrate the movable drive electrode and the movable detection electrode in the Y-axis direction (this vibration mode is called "driving vibration"). In this state, when an angular velocity around the X-axis is applied, the movable detection electrode vibrates in the Z-axis direction due to the Coriolis force (this vibration mode is called the "detection vibration mode"), and changes accordingly. The angular velocity about the X-axis can be detected based on the capacitance between the movable detection electrode and the fixed detection electrode.

Such an angular velocity sensor can be formed using, for example, the Bosch process, which is a silicon deep-groove etching technology described in Patent Document 2. The silicon deep-groove etching technology alternately repeats the etching process and the side wall protective film forming process by alternately switching two systems of gas, SF ₆ as an etching gas and C ₄ F ₈ as a side wall protective film forming gas. This is a technique for forming deep trenches in silicon. According to such a deep groove etching technique, grooves with excellent verticality of the groove side surfaces and a high aspect ratio can be formed.

JP 2009-175079 A Japanese Patent Publication No. 7-503815

However, when the deep groove etching technique described in Patent Document 2 is used, shape deviation may occur due to manufacturing errors. If the shape deviation occurs, unnecessary vibration occurs in the movable detection electrode in the driving vibration mode, and the angular velocity detection characteristics deteriorate. The unnecessary vibration of the movable detection electrodes in the driving vibration mode is also called a "quadrature", and the noise signal caused by this quadrature is also called a "quadrature signal".

In the inertial sensor of the present disclosure, when the three mutually orthogonal axes are the X-axis, the Y-axis, and the Z-axis,
a substrate;
a structure arranged on the substrate;
The structure is
a driving movable body disposed facing the substrate along the Z-axis;
a movable detection electrode supported by the driving movable body;
a fixed detection electrode provided on the substrate and facing the movable detection electrode in a direction along the Y-axis;
a drive spring supporting the movable drive body so as to be displaceable in a direction along the X-axis;
a driving unit that vibrates the driving movable body in a direction along the X-axis;
and a first adjustment unit that adjusts the spring constant of the drive spring.

2 is a plan view showing the inertial sensor of the first embodiment; FIG. FIG. 2 is a cross-sectional view along the line AA in FIG. 1; The top view which shows one structure. The top view which shows the other structure. The figure which shows the voltage applied to a sensor element. FIG. 4 is a plan view showing a quadrature of sensor elements; The perspective view which shows a 1st adjustment part. The top view which shows the inertial sensor of 2nd Embodiment. The perspective view which shows a 2nd adjustment part. The perspective view which shows the 3rd adjustment part which the inertial sensor of 3rd Embodiment has. The top view which shows the smart phone of 4th Embodiment. FIG. 11 is an exploded perspective view showing an inertial measurement device according to a fifth embodiment; FIG. 13 is a perspective view of a substrate included in the inertial measurement device shown in FIG. 12; FIG. 12 is a block diagram showing the overall system of the mobile positioning device of the sixth embodiment; FIG. 15 is a diagram showing the operation of the mobile positioning device shown in FIG. 14; The perspective view which shows the mobile body of 7th Embodiment.

Hereinafter, the inertial sensor, the electronic device, and the mobile object of the present disclosure will be described in detail based on the embodiments shown in the accompanying drawings.

<First embodiment>
FIG. 1 is a plan view showing the inertial sensor of the first embodiment. FIG. FIG. 2 is a cross-sectional view taken along line AA in FIG. FIG. 3 is a plan view showing one structure. FIG. 4 is a plan view showing the other structure. FIG. 5 is a diagram showing voltages applied to the sensor element. FIG. 6 is a plan view showing a quadrature of sensor elements. FIG. 7 is a perspective view showing a first adjusting section;

Each figure shows an X-axis, a Y-axis and a Z-axis as three mutually orthogonal axes. Also, the direction along the X-axis, that is, the direction parallel to the X-axis is also called the "X-axis direction", the direction along the Y-axis is also called the "Y-axis direction", and the direction along the Z-axis is also called the "Z-axis direction". Also, the arrow tip side of each axis is also called the "plus side", and the opposite side is also called the "minus side". The positive side in the Z-axis direction is also called "upper", and the negative side in the Z-axis direction is also called "lower". In the specification of the present application, "perpendicular" includes not only the case of intersecting at 90°, but also the case of intersecting at an angle slightly inclined from 90°, for example, within the range of 90°±5°.

The inertial sensor 1 shown in FIG. 1 is an angular velocity sensor capable of detecting an angular velocity ωz about the Z-axis. The inertial sensor 1 has a substrate 2 , a lid 3 and a sensor element 4 .

The substrate 2 overlaps the sensor element 4 and has a concave portion 21 open to the upper surface side. The concave portion 21 functions as a relief portion for suppressing contact between the sensor element 4 and the substrate 2 . Further, the substrate 2 has grooves open on its upper surface, and wirings 71, 72, 73, 74, and 75 are arranged in these grooves. One ends of the wirings 71 to 75 are exposed outside the lid 3 and function as electrode pads P for electrical connection with an external device. The electrode pads P are arranged on one long side of the substrate 2 . As a result, the gap between the electrode pads P can be sufficiently spaced, so that the leak current between the electrode pads P can be reduced satisfactorily.

Such a substrate 2 is made of, for example, a glass material containing alkali metal ions such as sodium ions, specifically borosilicate glass such as Tempax glass (registered trademark) or Pyrex glass (registered trademark). A glass substrate can be used. However, the constituent material of the substrate 2 is not particularly limited, and a silicon substrate, a ceramic substrate, or the like may be used.

As shown in FIG. 2, the lid 3 has a recess 31 that opens downward. The lid 3 accommodates the sensor element 4 in the recess 31 and is bonded to the upper surface of the substrate 2 . The lid 3 and the substrate 2 form a storage space S in which the sensor element 4 is hermetically stored. Further, the lid 3 is provided with a through hole 32 that communicates the inside and outside of the accommodation space S, and the through hole 32 is sealed with a sealing material 33 . In other words, the storage space S is shielded from the atmosphere outside the inertial sensor 1 by the sealing material 33 and the bonding material 39 . The storage space S is preferably in a decompressed state, particularly in a vacuum state. As a result, the viscous resistance is reduced, and the sensor element 4 can be efficiently vibrated.

A silicon substrate, for example, can be used as such a lid 3 . However, the lid 3 is not particularly limited, and for example, a glass substrate or a ceramics substrate may be used. Also, the method of joining the substrate 2 and the lid 3 is not particularly limited, and may be appropriately selected depending on the materials of the substrate 2 and the lid 3. A substrate 2 and a lid 3 are joined via a frit material.

The sensor element 4 is arranged in the storage space S and bonded to the upper surface of the substrate 2 . The sensor element 4 is formed by patterning a conductive silicon substrate 400 doped with impurities such as phosphorus (P), boron (B), arsenic (As), etc., by the Bosch process, which is a deep-groove etching technique. It is However, the method for forming the sensor element 4 is not limited to this. In addition, the silicon substrate 400 has a substantially uniform thickness t over the entire area except for the first adjusting portion 5, which will be described later.

As shown in FIG. 1, the sensor element 4 has two structures 40A and 40B arranged in the X-axis direction. The structures 40A and 40B have shapes that are 180° rotationally symmetrical with respect to the center O of the sensor element 4 . Each structure 40A, 40B includes a frame-shaped movable drive body 41, a fixed part 42 fixed to the substrate 2, a drive spring 43 connecting the movable drive body 41 and the fixed part 42, and a movable drive body 41. in the X-axis direction, a detection movable body 45 arranged inside the drive movable body 41, a detection spring 46 connecting the detection movable body 45 and the drive movable body 41, a detection movable body 45 and a detection unit 47 for detecting vibration in the Y-axis direction.

Further, the driving movable body 41 has a rectangular frame shape. As shown in FIGS. 3 and 4 , the fixed part 42 has four fixed parts 421 , 422 , 423 , 424 arranged around the driving movable body 41 . The four fixing parts 421 to 424 are arranged corresponding to the four corners of the driving movable body 41 . Specifically, a virtual axis that intersects the center O41 of the drive movable body 41 and extends in the X-axis direction is defined as a virtual X-axis Lx, and a virtual axis that extends in the Y-axis direction is defined as a virtual Y-axis Ly. Assuming that the four quadrants partitioned by the Y-axis Ly are the first quadrant E1, the second quadrant E2, the third quadrant E3, and the fourth quadrant E4, the fixed part 422 is arranged in the first quadrant E1 and the second quadrant E2. A fixing portion 421 is arranged, a fixing portion 424 is arranged in the third quadrant E3, and a fixing portion 423 is arranged in the fourth quadrant E4.

According to such an arrangement, the four fixed portions 421 to 424 can be arranged around the driving movable body 41 in a well-balanced manner, and the driving movable body 41 can be supported in a well-balanced manner. In this embodiment, the fixing portion 421 of the structural body 40A and the fixing portion 424 of the structural body 40B are shared, and the fixing portion 424 of the structural body 40A and the fixing portion 421 of the structural body 40B are shared. . Thereby, size reduction of the sensor element 4 can be achieved. However, the arrangement of the four fixing portions 421 to 424 is not particularly limited, and the number of fixing portions 42 is not limited to four.

Also, the drive spring 43 has four drive springs 431 , 432 , 433 and 434 . The drive spring 432 connects the corner of the movable drive body 41 located in the first quadrant E1 and the fixed part 422, and the drive spring 431 connects the corner of the movable drive body 41 located in the second quadrant E2. The drive spring 434 connects the corner of the movable drive body 41 located in the third quadrant E3 and the fixed part 424, and the drive spring 433 connects the movable drive body located in the fourth quadrant E4. A corner portion of the body 41 and the fixing portion 423 are connected. That is, the driving movable body 41 is supported by the driving springs 43 at its four corners. As a result, the posture of the driving movable body 41 is stabilized. Further, each of the drive springs 431 to 434 has a meandering shape and is elastically deformable in the X-axis direction.

The drive section 44 has a movable drive electrode 440 connected to the drive movable body 41 and a fixed drive electrode 445 fixed to the substrate 2 .

The movable drive electrode 440 protrudes from the drive movable body 41 to the Y-axis direction plus side and is arranged in the X-axis direction. It has two movable drive electrodes 443 and 444 aligned in the direction. The movable drive electrodes 441, 442 and the movable drive electrodes 443, 444 are line-symmetrical with respect to the virtual X-axis Lx, and the movable drive electrodes 441, 444 and the movable drive electrodes 442, 443 are linearly symmetrical with respect to the virtual Y-axis Ly is axisymmetric with respect to Each of the four movable drive electrodes 441 to 444 is composed of a comb tooth electrode having a plurality of electrode fingers arranged in a comb tooth shape.

The fixed drive electrode 445 includes a fixed drive electrode 446 arranged corresponding to the movable drive electrode 441 , a fixed drive electrode 447 arranged corresponding to the movable drive electrode 442 , and a fixed drive electrode 447 arranged corresponding to the movable drive electrode 443 . It has a fixed drive electrode 448 arranged and a fixed drive electrode 449 arranged corresponding to the movable drive electrode 444 .

In addition, the fixed drive electrode 446 has a first fixed drive electrode 446a and a second fixed drive electrode 446b arranged with the movable drive electrode 441 interposed therebetween. Similarly, fixed drive electrode 447 has a first fixed drive electrode 447a and a second fixed drive electrode 447b with movable drive electrode 442 interposed therebetween, and fixed drive electrode 448 has movable drive electrode 443 therebetween. The fixed drive electrode 449 has a first fixed drive electrode 448a and a second fixed drive electrode 448b arranged with the movable drive electrode 444 interposed therebetween. and a second fixed drive electrode 449b.

Further, the detection movable body 45 is arranged inside the drive movable body 41 . The detection movable body 45 has a rectangular frame shape and is arranged concentrically with the drive movable body 41 .

Also, the detection spring 46 has four detection springs 461 , 462 , 463 and 464 . The detection spring 462 connects the corner of the detection movable body 45 located in the first quadrant E1 and the driving movable body 41, and the detection spring 461 connects the corner of the detection movable body 45 located in the second quadrant E2. and the drive movable body 41, the detection spring 464 connects the corner of the detection movable body 45 located in the third quadrant E3 and the drive movable body 41, and the detection spring 463 is located in the fourth quadrant E4. The corner of the detecting movable body 45 and the driving movable body 41 are connected. That is, the detection movable body 45 is supported by the detection springs 46 at its four corners. As a result, the posture of the detection movable body 45 is stabilized. Further, each of the detection springs 461 to 464 has a meandering shape and is elastically deformable in the Y-axis direction.

Further, the detection section 47 has a movable detection electrode 470 connected to the detection movable body 45 and a fixed detection electrode 475 fixed to the substrate 2 .

The movable detection electrode 470 has a plurality of electrode fingers 471 arranged inside the detection movable body 45 . The plurality of electrode fingers 471 extend in the X-axis direction and are arranged side by side in the Y-axis direction. The fixed detection electrode 475 has a first fixed detection electrode 476 and a second fixed detection electrode 477 facing each other with each electrode finger 471 interposed therebetween. In the structural body 40A, the first fixed detection electrode 476 is positioned on the positive side in the Y-axis direction with respect to the electrode finger 471, and the second fixed detection electrode 477 is positioned on the negative side in the Y-axis direction. Conversely, in the structure 40B, the first fixed detection electrode 476 is positioned on the negative side in the Y-axis direction with respect to the electrode finger 471, and the second fixed detection electrode 477 is positioned on the positive side in the Y-axis direction.

The sensor element 4 has been briefly described above. In addition, hereinafter, the assembly of the drive movable body 41, the detection spring 46, the detection movable body 45, and the movable detection electrode 470 is also referred to as the "movable body 48". Among such sensor elements 4, the movable body 48 is electrically connected to the wiring 71, the first fixed driving electrodes 446a to 449a are electrically connected to the wiring 72, and the second fixed driving electrodes 446b to 449b are connected to the wiring. 73 , the first fixed detection electrode 476 is electrically connected to the wiring 74 , and the second fixed detection electrode 477 is electrically connected to the wiring 75 . The wirings 74 and 75 are each connected to a charge amplifier via an electrode pad P. A capacitance Ca is formed between the movable detection electrode 470 and the first fixed detection electrode 476, A capacitance Cb is formed between it and the second fixed detection electrode 477 .

For example, the DC voltage V1 shown in FIG. 5 is applied to the movable body 48 through the wiring 71, the AC voltage V2 shown in FIG. When an AC voltage V3, which is opposite in phase to the AC voltage V2 shown in FIG. , the two movable bodies 48 vibrate in opposite phases so as to repeatedly approach and separate in the X-axis direction. This is because, in general, the electrostatic attractive force that alternately approaches and separates the movable body 48 is generated in proportion to the product of the DC voltage and the AC voltage. In addition, below, this vibration mode is also called "driving vibration mode."

When the angular velocity ωz is applied to the sensor element 4 while the two movable bodies 48 are being driven in the drive vibration mode, the Coriolis force causes the two movable bodies 48 to move as indicated by the arrow E in FIG. 45 vibrate in the Y-axis direction in opposite phases, and the capacitances Ca and Cb change with this vibration. Therefore, the angular velocity ωz received by the sensor element 4 can be obtained based on the changes in the capacitances Ca and Cb. In addition, below, this vibration mode is also called "detection vibration mode."

Note that the voltages V1, V2, and V3 are not particularly limited as long as they can excite the drive vibration mode. In addition, the inertial sensor 1 of the present embodiment employs an electrostatic driving method in which the driving vibration mode is excited by electrostatic attraction, but the method for exciting the driving vibration mode is not particularly limited. , an electromagnetic drive system using the Lorentz force of a magnetic field, or the like can also be applied.

Here, in the driving vibration mode described above, ideally, it is preferable that the two movable bodies 48 vibrate in the X-axis direction. In other words, in the driving vibration mode, it is preferable not to vibrate in directions other than the X-axis direction, especially in the Y-axis direction. However, for example, a shape deviation occurs due to the etching accuracy of the silicon substrate 400, and this shape deviation causes the two movable bodies 48 to shift the Y-axis direction component as indicated by the arrow Q in FIG. It may vibrate in oblique directions, including. Thus, when the two movable bodies 48 obliquely vibrate, the capacitances Ca and Cb change even though the angular velocity ωz is not applied. As a result, noise is generated from the quadrature signal, and the detection accuracy of the angular velocity ωz is lowered. In the following description, the vibration of the movable body 48 in the driving vibration mode other than in the X-axis direction, particularly in the Y-axis direction, is also referred to as a quadrature.

Therefore, the inertial sensor 1 has a first adjustment section 5 for reducing the quadrature. In addition, below, the case where the quadrature indicated by the arrow Q occurs due to the fact that the inertial sensor 1 is not provided with the first adjustment unit 5 as shown in FIG. 6 will be described as a representative example. In this case, the spring constants of the drive springs 431 and 432 of the structures 40A and 40B are larger than the spring constants of the drive springs 433 and 434 due to the shape deviation of the sensor element 4 caused by the etching accuracy described above. , 432 are more difficult to deform in the X-axis direction than the drive springs 433 and 434, which is considered to be one of the causes of quadrature generation. Therefore, in the inertial sensor 1, as shown in FIG. It is softened to the extent that it is balanced with 434.

Hereinafter, as shown in FIG. 7, the portion of the drive spring 431 extending in the Y-axis direction is also referred to as a beam 431a, and the portion connecting adjacent beams 431a at one end thereof is also referred to as a connection portion 431b. That is, the drive spring 431 includes a plurality of beams 431a extending in the Y-axis direction and arranged in the X-axis direction, and a plurality of connection portions that alternately connect the adjacent beams 431a on the positive side and the negative side in the Y-axis direction. 431b and . Similarly, the portion of the drive spring 432 extending in the Y-axis direction is also referred to as a beam 432a, and the portion connecting adjacent beams 432a at one end thereof is also referred to as a connection portion 432b. That is, the drive spring 432 includes a plurality of beams 432a extending in the Y-axis direction and arranged in the X-axis direction, and a plurality of connecting portions alternately connecting the adjacent beams 432a on the Y-axis direction plus side and the minus side. 432b and .

In the first adjusting portion 5, beams 431a and 432a are laser-processed. In the illustrated configuration, the upper ends of the beams 431a and 432a are rounded off by laser processing. By setting the wavelength of the laser light to about 350 to 1100 nm, the upper ends of the beams 431a and 432a made of silicon can be removed and the surfaces of the upper ends can be rounded. Therefore, the thickness t1 of the beams 431a and 432a is thinner than the thickness t2 (=t) of the drive springs 433 and 434. Therefore, the spring constants of the drive springs 431 and 432 can be reduced. The spring constants of the drive springs 431 and 432 are adjusted to the spring constants of the drive springs 433 and 434 by appropriately adjusting the region forming the first adjusting portion 5 and the thickness t1 of the drive springs 431 and 432. can enter. This suppresses the aforementioned quadrature and improves the detection accuracy of the angular velocity ωz.

In particular, in the present embodiment, the first adjustment portions 5 are formed in the drive springs 431 and 432 of the structure 40A and the drive springs 431 and 432 of the structure 40B, which are arranged symmetrically with respect to the center O. . Therefore, the quadrature can be suppressed by both of the two movable bodies 48, and the quadrature can be suppressed more effectively and in a well-balanced manner.

The configuration of the first adjustment unit 5 is not limited to the configuration described above as long as the spring constants of the drive springs 431 and 432 can be changed, and can be appropriately changed according to the size and orientation of the quadrature. For example, in the present embodiment, the first adjusting portion 5 is provided in a part of the longitudinal direction of each beam 431a, 432a, but it is not limited to this, and the entire longitudinal direction of each beam 431a, 432a is provided. may be provided. In addition, in the present embodiment, all the beams 431a and 432a are provided with the first adjusters 5, but the present invention is not limited to this. good. Further, in the present embodiment, the drive springs 431 and 432 have substantially the same configuration (thickness t1 and formation area) of the first adjustment portion 5, but the present invention is not limited to this. The configuration of the portion 5 may be varied. In addition, in the first adjustment portion 5 of the present embodiment, the upper ends of the beams 431a and 432a are rounded off by laser processing, but the present invention is not limited to this. It is also possible to shave only the corners.

Moreover, in the present embodiment, the first adjustment portion 5 is formed by laser processing, but the method for forming the first adjustment portion 5 is not limited to laser processing. For example, the first adjusting portion 5 may be formed by focused ion beam processing, by etching, or by half-cutting with a dicing saw or the like. Further, the first adjusting portion 5 may be configured such that the beams 431a and 432a are doped with an impurity at a higher concentration to change the physical properties of the beams 431a and 432a or to transform them into an amorphous state. good.

In this embodiment, the drive springs 431 to 434 are balanced by reducing the spring constants of the drive springs 431 and 432. Springs 431-434 may be balanced. A method for increasing the spring constant of the drive springs 433 and 434 is not particularly limited, but for example, a method of depositing a metal film or the like on the drive springs 433 and 434, or a method of filling a resin material or the like between adjacent beams. may be

Further, in the present embodiment, the drive springs 431 and 432 are provided with the first adjusting portion 5, but the present invention is not limited to this, and the first adjusting portion 5 is provided on at least one of the drive springs 431 to 434. It is good if there is

The inertial sensor 1 has been described above. As described above, such an inertial sensor 1 includes a substrate 2, a structure 40A (40B) arranged on the substrate 2, and three axes orthogonal to each other as the X axis, the Y axis, and the Z axis. have In addition, the structure 40A includes a driving movable body 41 arranged to face the substrate 2 along the Z-axis, a movable detection electrode 470 supported by the driving movable body 41, and provided on the substrate 2 and movable. First and second fixed detection electrodes 476 and 477 as fixed detection electrodes opposed to the detection electrode 470 in the direction along the Y-axis, and the driving movable body 41 are supported so as to be displaceable in the direction along the X-axis. It has drive springs 431-434, a drive section 44 that vibrates the drive movable body 41 in the direction along the X-axis, and a first adjustment section 5 that adjusts the spring constants of the drive springs 431-434. According to such a configuration, the spring constants of the driving springs 431 to 434 can be adjusted by the first adjusting section 5, and the hardness of the driving springs 431 to 434 can be balanced. Therefore, the inertial sensor 1 can effectively suppress the quadrature, and can suppress deterioration of the inertial detection characteristics due to the quadrature.

Further, as described above, the first adjustment portion 5 has a curved surface, and the thickness t1 of the first adjustment portion 5 in the direction along the Z axis is the Z thickness of the drive spring 43 in the region other than the first adjustment portion 5 . It is thinner than the thickness t2 (=t) in the direction along the axis. Thus, by reducing the thickness t1 of the drive spring 43 in the first adjusting portion 5, the spring constant of the drive spring 43 can be changed with a simple configuration, and the drive springs 431 to 434 can be more easily adjusted. hardness can be balanced.

As described above, the virtual axis that intersects the center O41 of the driving movable body 41 and is along the X axis is defined as the virtual X axis Lx, and the virtual axis that intersects the center O41 of the driving movable body 41 and is along the Y axis is defined as the virtual Y axis. Ly, and four quadrants defined by the virtual X-axis Lx and the virtual Y-axis Ly are defined as a first quadrant E1, a second quadrant E2, a third quadrant E3, and a fourth quadrant E4. A drive spring 432 as a first drive spring that supports the portion of the body 41 located in the first quadrant E1, and a drive spring 431 as a second drive spring that supports the portion of the movable drive body 41 located in the second quadrant E2. , a drive spring 434 as a third drive spring that supports a portion of the movable drive body 41 located in the third quadrant E3, and a fourth drive spring that supports a portion of the movable drive body 41 located in the fourth quadrant E4. and a drive spring 433 of . At least one of the drive springs 431 to 434 is formed with the first adjusting portion 5 . According to such a configuration, the driving movable body 41 can be supported in a well-balanced manner by the four driving springs 431-434. Therefore, quadrature is less likely to occur.

Further, as described above, the first quadrant E1 and the second quadrant E2, and the third quadrant E3 and the fourth quadrant E4 are arranged with the virtual X-axis Lx interposed therebetween. An adjusting portion 5 is formed. Thus, by forming the first adjusting portion 5 on the two drive springs 431 and 432 located on one side with respect to the virtual X-axis Lx, it is possible to more effectively suppress the quadrature in the Y-axis direction. can.

In addition, as described above, the inertial sensor 1 has two structures 40A and 40B arranged side by side in the direction along the X-axis. The drive movable body 41 included in the structure 40B vibrates in the direction along the X-axis in the opposite phase. As a result, vibrations can be canceled between the driving movable bodies 41, so that vibration leakage is suppressed, and the inertial sensor 1 has better detection characteristics of the angular velocity ωz.

Further, as described above, in one structure 40A, the drive springs 431 and 432 in which the first adjustment portion 5 is formed are arranged on one side of the virtual X-axis Lx, in this embodiment, on the Y-axis direction plus side. In the other structure 40B, the drive springs 431 and 432 in which the first adjustment portion 5 is formed are located on the other side of the virtual X-axis Lx, in this embodiment, on the Y-axis direction minus side. . In this way, by symmetrically arranging the drive springs forming the first adjustment portion 5 with the structures 40A and 40B, the quadrature can be more effectively suppressed.

<Second embodiment>
FIG. 8 is a plan view showing the inertial sensor of the second embodiment. FIG. 9 is a perspective view showing a second adjusting section;

This embodiment is the same as the above-described first embodiment except that the second adjusting portion 6 formed in the driving movable body 41 is provided. In addition, in the following description, regarding this embodiment, differences from the above-described embodiment will be mainly described, and the description of the same matters will be omitted. In addition, in FIGS. 8 and 9, the same reference numerals are given to the same configurations as in the above-described embodiment.

As shown in FIG. 8 , the inertial sensor 1 of this embodiment has a second adjuster 6 that adjusts the position of the center of gravity G of the drive movable body 41 . For example, when a large quadrature occurs, it may not be possible to cancel the quadrature with only the first adjustment unit 5 . Therefore, the inertial sensor 1 is further provided with the second adjustment section 6, and cooperates with the first adjustment section 5 to effectively suppress the quadrature. The second adjustment unit 6 cancels the quadrature that cannot be canceled by the first adjustment unit 5 by shifting the position of the center of gravity G of the drive movable body 41 .

As shown in FIG. 8, in the structure 40A, the center of gravity G of the driving movable body 41 is set to the positive side in the Y-axis direction so as to cancel the quadrature indicated by the arrow Q1 even after the first adjustment unit 5 has left the quadrature. The second adjustment portion 6 is formed so as to be shifted, and in the structure 40B, the second adjustment portion 6 is formed so that the center of gravity G of the driving movable body 41 is shifted to the negative side in the Y-axis direction. As a result, in the structure 40A, the moment of the portion 411 located on the Y-axis direction plus side with respect to the virtual X-axis Lx increases, and the moment of the portion 412 located on the Y-axis direction minus side decreases. In the structure 40B, the moment of the portion 411 located on the negative side in the Y-axis direction with respect to the virtual X-axis Lx increases, and conversely, the moment of the portion 412 located on the positive side in the Y-axis direction increases Decrease suppresses the quadrature.

In the second adjusting portion 6 of the present embodiment, as shown in FIG. 9, the end portion of the driving movable body 41 of the structural body 40A on the negative side in the Y-axis direction is cut by laser processing. 41 is shifted to the positive side in the Y-axis direction. Similarly, the end of the driving movable body 41 of the structure 40B on the Y-axis direction positive side is cut by laser processing, thereby shifting the gravity center G of the driving movable body 41 to the Y-axis direction negative side.

The configuration of the second adjusting section 6 is not limited to the configuration described above as long as the position of the center of gravity G of the drive movable body 41 can be shifted. For example, a weight such as a metal film is placed at the end of the driving movable body 41 of the structural body 40A on the positive side in the Y-axis direction to shift the center of gravity G to the positive side in the Y-axis direction. A weight such as a metal film may be arranged at the end on the negative side in the axial direction to shift the center of gravity G to the negative side in the Y-axis direction.

As described above, the inertial sensor 1 of the present embodiment has the second adjuster 6 that adjusts the position of the center of gravity of the drive movable body 41 . Even if the quadrature cannot be completely canceled by the first adjustment unit 5 alone, the cooperation of the first adjustment unit 5 and the second adjustment unit 6 can effectively suppress the quadrature.

Such a second embodiment can also exhibit the same effect as the first embodiment described above.

<Third Embodiment>
FIG. 10 is a perspective view showing a third adjuster included in the inertial sensor of the third embodiment;

This embodiment is the same as the above-described first embodiment except that the third adjustment section 8 formed in the detection section 47 is provided. In addition, in the following description, regarding this embodiment, differences from the above-described embodiment will be mainly described, and the description of the same matters will be omitted. Moreover, in FIG. 10, the same reference numerals are given to the same configurations as in the above-described embodiment.

As shown in FIG. 10, the inertial sensor 1 of this embodiment has a third adjuster 8 formed in the detector 47 and adjusting the capacitances Ca and Cb. For example, if a shape deviation occurs due to the etching accuracy of the silicon substrate 400 and a difference occurs between the capacitances Ca and Cb in the natural state, an unnecessary signal corresponding to the difference is generated. Therefore, in the present embodiment, the third adjustment section 8 is formed in the detection section 47 so that the difference between the capacitances Ca and Cb becomes small, preferably so that the capacitances Ca and Cb become equal. The smaller the difference between the capacitances Ca and Cb in the natural state, the less likely signal saturation will occur even if the gain of the charge amplifier to which the first and second fixed detection electrodes 476 and 477 are connected is increased, thus reducing noise. be able to. Note that in the present embodiment, Ca>Cb before forming the third adjusting portion 8 .

In the third adjusting portion 8 of the present embodiment, part of the first fixed detection electrode 476 is cut by laser processing. As a result, the facing area between the first fixed detection electrode 476 and the electrode finger 471 decreases, the average distance between them increases, and the capacitance Ca decreases. Therefore, the difference between the capacitances Ca and Cb can be reduced.

Note that the configuration of the third adjustment unit 8 is not limited to the configuration described above as long as the difference between the capacitances Ca and Cb can be reduced. For example, by forming a metal film on the surface of the second fixed detection electrode 477, the facing area between the second fixed detection electrode 477 and the electrode fingers 471 is increased, the average separation distance between them is decreased, and the capacitance is increased. Cb may be increased to equal capacitance Ca.

As described above, the inertial sensor 1 of this embodiment has the third adjuster 8 that adjusts the capacitances Ca and Cb between the movable detection electrode 470 and the fixed detection electrode 475 . Thereby, the difference between the capacitances Ca and Cb can be reduced, and noise can be reduced.

Such a third embodiment can also exhibit the same effect as the first embodiment described above.

<Fourth Embodiment>
FIG. 11 is a plan view showing the smart phone of the fourth embodiment.

A smartphone 1200 shown in FIG. 11 incorporates an inertial sensor 1 and a control circuit 1210 that performs control based on a detection signal output from the inertial sensor 1 . Detection data detected by the inertial sensor 1 is transmitted to the control circuit 1210, and the control circuit 1210 recognizes the posture and behavior of the smartphone 1200 from the received detection data, and displays the display image displayed on the display unit 1208. You can change it, play warning sounds and sound effects, and drive the vibration motor to vibrate the main body.

A smartphone 1200 as such an electronic device has an inertial sensor 1 . Therefore, the effects of the inertial sensor 1 described above can be enjoyed, and high reliability can be exhibited.

In addition, the electronic device incorporating the inertial sensor 1 is not particularly limited, and other than the smartphone 1200, for example, a personal computer, a digital still camera, a tablet terminal, a watch, a smart watch, an inkjet printer, a laptop personal computer, TVs, wearable terminals such as HMDs (head-mounted displays), video cameras, video tape recorders, car navigation devices, pagers, electronic notebooks, electronic dictionaries, calculators, electronic game devices, word processors, workstations, videophones, security TV monitors , electronic binoculars, POS terminals, medical equipment, fish finders, various measuring equipment, mobile terminal base station equipment, various instruments for vehicles, aircraft, ships, flight simulators, network servers, and the like.

<Fifth Embodiment>
FIG. 12 is an exploded perspective view showing the inertial measurement device of the fifth embodiment. 13 is a perspective view of a substrate included in the inertial measurement device shown in FIG. 12. FIG.

An inertial measurement unit 2000 (IMU: Inertial Measurement Unit) shown in FIG. 12 is an inertial measurement unit that detects the posture and behavior of a wearable device such as an automobile or a robot. Inertial measurement device 2000 functions as a 6-axis motion sensor with a 3-axis acceleration sensor and a 3-axis angular velocity sensor.

The inertial measurement device 2000 is a cuboid with a substantially square planar shape. Further, screw holes 2110 are formed as fixing portions in the vicinity of two vertexes located in the diagonal direction of the square. By passing two screws through the two screw holes 2110, the inertial measurement device 2000 can be fixed to a mounting surface of a mounting body such as an automobile. It should be noted that it is also possible to reduce the size to a size that can be mounted on a smartphone or a digital camera, for example, by selecting parts or changing the design.

The inertial measurement device 2000 includes an outer case 2100, a joint member 2200, and a sensor module 2300. The sensor module 2300 is inserted into the outer case 2100 with the joint member 2200 interposed therebetween. there is The external shape of the outer case 2100 is a rectangular parallelepiped with a substantially square planar shape, similar to the overall shape of the inertial measurement device 2000 described above, and screw holes 2110 are formed in the vicinity of two vertices located in the diagonal direction of the square. It is In addition, the outer case 2100 is box-shaped, and the sensor module 2300 is accommodated therein.

The sensor module 2300 has an inner case 2310 and a substrate 2320 . The inner case 2310 is a member that supports the substrate 2320 and has a shape that fits inside the outer case 2100 . Further, the inner case 2310 is formed with a concave portion 2311 for suppressing contact with the substrate 2320 and an opening 2312 for exposing a connector 2330 to be described later. Such inner case 2310 is joined to outer case 2100 via joining member 2200 . A substrate 2320 is bonded to the lower surface of the inner case 2310 with an adhesive.

As shown in FIG. 13, on the upper surface of the substrate 2320, a connector 2330, an angular velocity sensor 2340z for detecting angular velocity around the Z axis, an acceleration sensor 2350 for detecting acceleration in the directions of the X, Y and Z axes, etc. is implemented. Further, on the side surface of the substrate 2320, an angular velocity sensor 2340x for detecting angular velocity around the X axis and an angular velocity sensor 2340y for detecting angular velocity around the Y axis are mounted. Then, the inertial sensor of the present disclosure can be used as each of these sensors.

A control IC 2360 is mounted on the bottom surface of the substrate 2320 . The control IC 2360 is an MCU (Micro Controller Unit) and controls each part of the inertial measurement device 2000 . The storage unit stores a program that defines the order and contents for detecting acceleration and angular velocity, a program that digitizes detected data and incorporates it into packet data, accompanying data, and the like. A plurality of electronic components are also mounted on the substrate 2320 .

<Sixth embodiment>
FIG. 14 is a block diagram showing the overall system of the mobile positioning device of the sixth embodiment. 15A and 15B are diagrams showing the operation of the mobile positioning device shown in FIG.

A mobile object positioning device 3000 shown in FIG. 14 is a device that is attached to a mobile object and used to perform positioning of the mobile object. The mobile object is not particularly limited, and may be a bicycle, automobile, motorcycle, train, airplane, ship, or the like.

The mobile positioning device 3000 includes an inertial measurement unit 3100 (IMU), an arithmetic processing unit 3200, a GPS receiving unit 3300, a receiving antenna 3400, a position information acquisition unit 3500, a position synthesizing unit 3600, and a processing unit 3700. , a communication unit 3800 and a display unit 3900 . As the inertial measurement device 3100, for example, the inertial measurement device 2000 described above can be used.

The inertial measurement device 3100 has a triaxial acceleration sensor 3110 and a triaxial angular velocity sensor 3120 . The arithmetic processing unit 3200 receives acceleration data from the acceleration sensor 3110 and angular velocity data from the angular velocity sensor 3120, performs inertial navigation arithmetic processing on these data, and outputs inertial navigation positioning data including the acceleration and attitude of the moving body. do.

GPS receiver 3300 also receives signals from GPS satellites via receiving antenna 3400 . Also, the position information acquisition unit 3500 outputs GPS positioning data representing the position (latitude, longitude, altitude), speed, and direction of the mobile positioning device 3000 based on the signal received by the GPS reception unit 3300 . This GPS positioning data also includes status data indicating the reception state, reception time, and the like.

Based on the inertial navigation positioning data output from the arithmetic processing unit 3200 and the GPS positioning data output from the position information acquisition unit 3500, the position synthesizing unit 3600 determines the position of the mobile object, specifically, the position of the mobile object on the ground. Calculate whether the position is running. For example, even if the position of the mobile object included in the GPS positioning data is the same, as shown in FIG. , the moving body is running. Therefore, the accurate position of the moving object cannot be calculated only with GPS positioning data. Therefore, the position synthesizing unit 3600 uses the inertial navigation positioning data to calculate where on the ground the moving object is running.

The position data output from the position synthesizing unit 3600 undergoes predetermined processing by the processing unit 3700 and is displayed on the display unit 3900 as the positioning result. Also, the position data may be transmitted to the external device by the communication unit 3800 .

<Seventh embodiment>
FIG. 16 is a perspective view showing the moving body of the seventh embodiment.

An automobile 1500 as a moving object shown in FIG. 16 includes at least one system 1510 of an engine system, a brake system, and a keyless entry system. The automobile 1500 also incorporates an inertial sensor 1, and the inertial sensor 1 can detect the attitude of the vehicle body. A detection signal of the inertial sensor 1 is supplied to the control device 1502, and the control device 1502 can control the system 1510 based on the signal. In this way, automobile 1500 as a moving body has inertial sensor 1 . Therefore, the effects of the inertial sensor 1 described above can be enjoyed, and high reliability can be exhibited.

In addition, the inertial sensor 1 can also be used for car navigation systems, car air conditioners, anti-lock braking systems (ABS), airbags, tire pressure monitoring systems (TPMS), engine controls, hybrid vehicles. and electronic control units (ECUs) such as battery monitors for electric vehicles. Further, the mobile body is not limited to the automobile 1500, and can be applied to, for example, airplanes, rockets, artificial satellites, ships, AGVs (automated guided vehicles), bipedal walking robots, unmanned aircraft such as drones, and the like. .

Although the inertial sensor, the electronic device, and the moving object of the present invention have been described above based on the illustrated embodiments, the present invention is not limited to this, and the configuration of each part can be any configuration having similar functions. can be replaced with Further, in the above-described embodiment, the inertial sensor is configured to detect angular velocity, but is not limited to this, and may be configured to detect acceleration, for example.

DESCRIPTION OF SYMBOLS 1... Inertial sensor 2... Substrate 21... Recessed part 3... Lid 31... Recessed part 32... Through hole 33... Sealing material 39... Joining material 4... Sensor element 40A, 40B... Structure, 400 Silicon substrate 41 Driving movable body 411, 412 Part 42, 421 to 424 Fixed part 43, 431 to 434 Drive spring 431a, 432a Beam 431b, 432b Connecting part 44 Driving Part 440 to 444 Movable drive electrode 445 to 449 Fixed drive electrode 446a to 449a First fixed drive electrode 446b to 449b Second fixed drive electrode 45 Detection movable body 46, 461 to 464 Detection spring 47...Detection part 470...Movable detection electrode 471...Electrode finger 475...Fixed detection electrode 476...First fixed detection electrode 477...Second fixed detection electrode 48...Movable body 5...First Adjustment unit 6 Second adjustment unit 71 to 75 Wiring 8 Third adjustment unit 1200 Smartphone 1208 Display unit 1210 Control circuit 1500 Automobile 1502 Control device 1510 System DESCRIPTION OF SYMBOLS 2000... Inertial measuring device 2100... Outer case 2110... Screw hole 2200... Joint member 2300... Sensor module 2310... Inner case 2311... Recessed part 2312... Opening 2320... Substrate 2330... Connector 2340x, 2340y , 2340z... Angular velocity sensor 2350... Acceleration sensor 2360... Control IC 3000... Mobile positioning device 3100... Inertial measurement device 3110... Acceleration sensor 3120... Angular velocity sensor 3200... Arithmetic processor 3300... GPS receiver , 3400... Receiving antenna 3500... Positional information acquisition unit 3600... Position synthesizing unit 3700... Processing unit 3800... Communication unit 3900... Display unit D, E... Arrow, E1... First quadrant, E2... Second Quadrant E3... Third quadrant E4... Fourth quadrant G... Gravity center Lx... Virtual X axis Ly... Virtual Y axis O, O41... Center P... Electrode pad Q, Q1... Arrow S... Storage space t, t1, t2...Thickness V1, V2, V3...Voltage θ...Inclination ωz...Angular velocity

Claims (9)

When the three mutually orthogonal axes are the X-axis, Y-axis and Z-axis,
a substrate;
a structure arranged on the substrate;
The structure is
a driving movable body disposed facing the substrate along the Z-axis;
a movable detection electrode supported by the driving movable body;
a fixed detection electrode provided on the substrate and facing the movable detection electrode in a direction along the Y-axis;
a drive spring supporting the movable drive body so as to be displaceable in a direction along the X-axis;
a driving unit that vibrates the driving movable body in a direction along the X-axis;
a first adjustment unit that adjusts the spring constant of the drive spring;
and a second adjustment unit that adjusts the position of the center of gravity of the driving movable body . When the three mutually orthogonal axes are the X-axis, Y-axis and Z-axis,
a substrate;
a structure arranged on the substrate;
The structure is
a driving movable body disposed facing the substrate along the Z-axis;
a movable detection electrode supported by the driving movable body;
a fixed detection electrode provided on the substrate and facing the movable detection electrode in a direction along the Y-axis;
a drive spring supporting the movable drive body so as to be displaceable in a direction along the X-axis;
a driving unit that vibrates the driving movable body in a direction along the X-axis;
a first adjustment unit that adjusts the spring constant of the drive spring;
and a third adjuster that adjusts the capacitance between the movable detection electrode and the fixed detection electrode . The first adjusting portion has a curved surface,
3. The inertia according to claim 1, wherein the thickness of the first adjustment portion in the direction along the Z-axis is thinner than the thickness of the drive spring in the direction along the Z-axis in a region other than the first adjustment portion. sensor. A virtual axis that intersects the center of the driving movable body and is along the X axis is defined as a virtual X axis,
A virtual Y-axis is defined as a virtual axis that intersects the center of the driving movable body and is along the Y-axis;
When the four quadrants partitioned by the virtual X-axis and the virtual Y-axis are the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant,
The drive spring is
a first drive spring that supports a portion of the drive movable body located in the first quadrant;
a second drive spring that supports a portion of the drive movable body located in the second quadrant;
a third drive spring that supports a portion of the drive movable body located in the third quadrant;
a fourth drive spring that supports a portion of the drive movable body located in the fourth quadrant;
4. The first adjusting portion according to any one of claims 1 to 3 , wherein at least one of the first drive spring, the second drive spring, the third drive spring and the fourth drive spring is formed with the first adjusting portion. inertial sensor. The first quadrant and the second quadrant, and the third quadrant and the fourth quadrant are arranged with the virtual X axis interposed therebetween,
5. The inertial sensor according to claim 4 , wherein the first adjustment portion is formed in the first drive spring and the second drive spring. having two structures arranged side by side in a direction along the X-axis;
6. The movable drive body included in one of the structure bodies and the movable drive body included in the other structure body vibrate in opposite phases in the direction along the X-axis. Inertial sensor as described. In the one structure, the drive spring in which the first adjusting portion is formed is located on one side with respect to the virtual X axis,
7. The inertial sensor according to claim 6 , wherein, in said other structure, said drive spring in which said first adjusting portion is formed is located on the other side with respect to said virtual X-axis. An electronic device comprising the inertial sensor according to any one of claims 1 to 7 . A moving body comprising the inertial sensor according to any one of claims 1 to 7 .

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