Inertial sensor and vehicle

Abstract

To provide an inertial sensor that can improve the accuracy of detecting an angular velocity, and a vehicle.SOLUTION: An inertial sensor has: a package that has a housing space; a sensor unit that is arranged in the housing space, and includes a first acceleration sensor element and a first angular velocity sensor element; a second angular velocity sensor element that is arranged in the housing space in an exposed state, and has the same angular velocity detection axis as that of the first angular velocity sensor element; and a circuit element that is arranged in the housing space, and is electrically connected to the sensor unit and the second angular velocity sensor element.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an inertial sensor and a vehicle. [Background technology]

[0002] The inertial sensor module described in Patent Document 1 includes a base substrate, a first sensor, a second sensor, and a third sensor mounted on the base substrate, and a cover placed over the base substrate to cover the first, second, and third sensors. The first sensor is a three-axis angular velocity sensor including a first gyro sensor element that detects angular velocity around the X-axis, a second gyro sensor element that detects angular velocity around the Y-axis, and a third gyro sensor element that detects angular velocity around the Z-axis. The third sensor is a three-axis acceleration sensor including a first acceleration sensor element that detects acceleration in the X-axis direction, a second acceleration sensor element that detects acceleration in the Y-axis direction, and a third acceleration sensor element that detects acceleration in the Z-axis direction. The second sensor includes a vibration gyro sensor element that detects angular velocity around the Z-axis, and can detect angular velocity around the Z-axis with higher accuracy than the third gyro sensor element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-050622 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to improve the angular velocity detection accuracy of a vibration gyro sensor element, it is effective to increase the size of the vibration gyro sensor element. However, in the inertial sensor module of Patent Document 1, the vibration gyro sensor element is housed in a package. Therefore, the vibration gyro sensor element must be made smaller by the size of the package, making it difficult to further improve the angular velocity detection accuracy of the vibration gyro sensor element. [Means for solving the problem]

[0005] The inertial sensor of the present invention includes a package having an accommodation space; a sensor unit disposed in the accommodation space and including a first acceleration sensor element and a first angular velocity sensor element; a second angular velocity sensor element disposed in the accommodation space in an exposed state and having the same angular velocity detection axis as the first angular velocity sensor element; and a circuit element disposed in the accommodation space and electrically connected to the sensor unit and the second angular velocity sensor element.

[0006] A vehicle of the present invention includes the above-described inertial sensor, The angular velocity detection axis is along the yaw axis. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a top view showing the inside of the inertial sensor according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the inertial sensor as viewed from the negative Y-axis direction. [Figure 3] FIG. 10 is a cross-sectional view of the inertial sensor before sealing, as viewed from the negative side in the Y-axis direction. [Figure 4] FIG. 2 is a top view showing the inside of the sensor unit. [Figure 5] FIG. 10 is a cross-sectional view of the sensor unit as seen from the negative side in the Y-axis direction. [Figure 6] This is a cross-sectional view of the three-axis angular velocity sensor as seen from the negative side in the X-axis direction. [Figure 7] This is a cross-sectional view of the 3-axis acceleration sensor as seen from the negative side in the X-axis direction. [Figure 8] FIG. 2 is a top view of the angular velocity sensor element. [Figure 9] FIG. 2 is a schematic diagram showing a driving state of an angular velocity sensor. [Figure 10] FIG. 2 is a schematic diagram showing a driving state of an angular velocity sensor. [Figure 11] FIG. 2 is a top view showing the sizes of an angular velocity sensor element, a sensor unit, and a circuit element. [Figure 12] FIG. 2 is a block diagram showing the functions of circuit elements. [Figure 13] FIG. 2 is a cross-sectional view showing a modified example of the inertial sensor shown in FIG. [Figure 14] FIG. 2 is a cross-sectional view showing a modified example of the inertial sensor shown in FIG. [Figure 15] FIG. 2 is a cross-sectional view showing a modified example of the inertial sensor shown in FIG. [Figure 16] FIG. 2 is a cross-sectional view showing a modified example of the inertial sensor shown in FIG. [Figure 17] FIG. 2 is a cross-sectional view showing a modified example of the inertial sensor shown in FIG. [Figure 18] FIG. 2 is a cross-sectional view showing a modified example of the inertial sensor shown in FIG. [Figure 19] FIG. 10 is a schematic diagram showing a vehicle according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] The inertial sensor and vehicle of the present invention will be described in detail below based on the embodiments shown in the accompanying drawings. For ease of explanation, each figure except for FIG. 12 illustrates three mutually orthogonal axes as the X-axis, Y-axis, and Z-axis. For ease of explanation, the direction parallel to the X-axis, which is the first axis direction, will also be referred to as the "X-axis direction," the direction parallel to the Y-axis, which is the second axis direction, will also be referred to as the "Y-axis direction," and the direction parallel to the Z-axis will also be referred to as the "Z-axis direction." The arrowed side of the Z-axis direction will also be referred to as the "upper" side, and the opposite side as the "lower" side.

[0009] First Embodiment FIG. 1 is a top view showing the inside of the inertial sensor according to the first embodiment. FIG. 2 is a cross-sectional view of the inertial sensor as seen from the negative side in the Y-axis direction. FIG. 3 is a cross-sectional view of the inertial sensor before sealing as seen from the negative side in the Y-axis direction. FIG. 4 is a top view showing the inside of the sensor unit. FIG. 5 is a cross-sectional view of the sensor unit as seen from the negative side in the Y-axis direction. FIG. 6 is a cross-sectional view of the three-axis angular velocity sensor as seen from the negative side in the X-axis direction. FIG. 7 is a cross-sectional view of the three-axis acceleration sensor as seen from the negative side in the X-axis direction. FIG. 8 is a top view of the angular velocity sensor element. FIGS. 9 and 10 are schematic diagrams each showing the driving state of the angular velocity sensor. FIG. 11 is a top view showing the sizes of the angular velocity sensor element, the sensor unit, and the circuit element. FIG. 12 is a block diagram showing the function of the circuit element. FIGS. 13 to 18 are cross-sectional views each showing a modified example of the inertial sensor shown in FIG. 1.

[0010] The inertial sensor 1 shown in FIGS. 1 and 2 includes a package 2, a sensor unit 3 housed in the package 2, an angular velocity sensor element 4 as a second angular velocity sensor element, a support substrate 5, and a circuit element 6.

[0011] [Package 2] First, the package 2 will be described. As shown in FIGS. 1 and 2, the package 2 has a cavity-shaped base 21 having a recess 211 opening to its upper surface, and a plate-shaped lid 22 that is joined to the upper surface of the base 21 via a seam ring 23 and closes the opening of the recess 211. Closing the recess 211 with the lid 22 forms an airtight storage space S within the package 2, and the sensor unit 3, angular velocity sensor element 4, support substrate 5, and circuit element 6 are housed within this storage space S. The storage space S is hermetically sealed and is in a reduced pressure state, preferably a state closer to a vacuum. This reduces viscous resistance within the storage space S, improving the vibration characteristics of the angular velocity sensor element 4 that is disposed exposed within the storage space S. However, the atmosphere within the storage space S is not particularly limited.

[0012] As shown in FIG. 3 , a groove 221 is formed on the back surface of the lid 22 before hermetically sealing. The groove 221 is provided on the outer edge of the lid 22 on the positive side in the X-axis direction, and its groove width in the Y-axis direction is smaller than the dimension of the storage space S in the Y-axis direction. The groove 221 spans the storage space S and the seam ring 23 in a plan view, and the groove 221 remains unwelded even after the lid 22 and the seam ring 23 are seam-welded. This allows communication between the inside and outside of the storage space S via the groove 221. Then, after evacuating the storage space S through the groove 221, an energy beam EL such as a laser beam is irradiated near the groove 221 of the lid 22 to melt the groove 221, thereby closing the groove 221. This hermetically seals the storage space S. However, the method for hermetically sealing the storage space S is not particularly limited.

[0013] It is preferable that the groove 221 is spaced apart from the angular velocity sensor element 4. This effectively prevents droplets of the lid 22 that are scattered within the accommodation space S during irradiation with the energy ray EL from adhering to the angular velocity sensor element 4 and deteriorating the vibration characteristics of the angular velocity sensor element 4. In this embodiment, since the angular velocity sensor element 4 is disposed closer to the negative side in the X-axis direction within the accommodation space S, the groove 221 is formed at the end on the positive side in the X-axis direction, i.e., the end opposite the angular velocity sensor element 4.

[0014] The constituent material of the base 21 is not particularly limited, but various ceramics such as aluminum oxide can be used. The constituent material of the lid 22 is also not particularly limited, but it is preferable that the constituent material has a linear expansion coefficient similar to that of the constituent material of the base 21. For example, if the constituent material of the base 21 is ceramic, it is preferable that the lid 22 be made of an alloy such as Kovar.

[0015] 1 and 2, the recess 211 has a first recess 211a that opens to the top surface of the base 21, a second recess 211b that opens to the bottom surface of the first recess 211a and has a smaller opening area than the first recess 211a, and a third recess 211c that opens to the bottom surface of the second recess 211b and has a smaller opening area than the second recess 211b. The angular velocity sensor element 4 is mounted on the bottom surface of the first recess 211a via a support substrate 5, and the sensor unit 3 and the circuit element 6 are mounted on the bottom surface of the third recess 211c, aligned in the X-axis direction. The sensor unit 3 and the angular velocity sensor element 4 are electrically connected to the circuit element 6 via terminals and internal wiring (not shown) formed on the base 21.

[0016] [Sensor unit 3] Next, we will explain the sensor unit 3. The sensor unit 3 is a composite sensor unit that detects three-axis angular velocity and three-axis acceleration, and is mounted on the bottom surface of the third recess 211c as shown in FIGS.

[0017] 4 and 5, the sensor unit 3 has a substrate 31 to which leads 30 are attached, a triaxial angular velocity sensor 32, a triaxial acceleration sensor 33, and a circuit element 34 mounted on the upper surface of the substrate 31, and a molding member 35 that molds the triaxial angular velocity sensor 32, the triaxial acceleration sensor 33, and the circuit element 34 with the tips of the leads 30 exposed as terminals. Note that, hereinafter, the surface on which the terminals are exposed will also be referred to as the "terminal surface."

[0018] However, the configuration of the sensor unit 3 is not particularly limited, and may be, for example, a package structure in which the 3-axis angular velocity sensor 32, the 3-axis acceleration sensor 33, and the circuit element 34 are housed in a ceramic package or the like, rather than a molded structure in which they are molded and sealed by a molding member 35.

[0019] -3-axis angular velocity sensor 32- The three-axis angular velocity sensor 32 can detect an angular velocity ωx around the X-axis, an angular velocity ωy around the Y-axis, and an angular velocity ωz around the Z-axis. The three-axis angular velocity sensor 32 is a silicon MEMS (Micro Electro Mechanical Systems). Therefore, the three-axis angular velocity sensor 32 can be made smaller.

[0020] 6, the three-axis angular velocity sensor 32 has a package 320, and an X-axis angular velocity sensor element 322x, a Y-axis angular velocity sensor element 322y, and a Z-axis angular velocity sensor element 322z as first angular velocity sensor elements housed in the package 320. The package 320 also has a base 321 having a recess on its upper surface on which the sensor elements 322x, 322y, and 322z are arranged so as to overlap this recess, and a lid 323 joined to the upper surface of the base 321 and housing the sensor elements 322x, 322y, and 322z between the package 320 and the base 321.

[0021] Such a triaxial angular velocity sensor 32 can be formed, for example, by a process of forming a base 321 from one silicon layer (handle layer) of an SOI (silicon on insulator) substrate, and forming each of the sensor elements 322x, 322y, 322z from the other silicon layer (device layer), and a process of bonding a lid 323 formed from a silicon substrate to the base 321. With this configuration, the triaxial angular velocity sensor 32 can be manufactured by a manufacturing method that complies with a silicon semiconductor process.

[0022] The X-axis angular velocity sensor element 322x, the Y-axis angular velocity sensor element 322y, and the Z-axis angular velocity sensor element 322z will be briefly described below.

[0023] The X-axis angular velocity sensor element 322x includes a fixed comb electrode fixed to the base 321, a movable comb electrode that is disposed to mesh with the fixed comb electrode and is displaceable in two directions, the Y-axis and the Z-axis, relative to the base 321, and a drive comb electrode for vibrating the movable comb electrode in the Y-axis direction. When an angular velocity ωx about the X-axis is applied to the X-axis angular velocity sensor element 322x while the movable comb electrode is vibrating in the Y-axis direction by energizing the drive comb electrode (drive vibration state), Coriolis force excites a detection vibration in the Z-axis direction in the movable comb electrode, and the capacitance between the fixed comb electrode and the movable comb electrode changes in response to the detection vibration. Therefore, the change in capacitance can be extracted as an output signal, and the angular velocity ωx can be detected based on the output signal. However, the configuration of the X-axis angular velocity sensor element 322x is not particularly limited as long as it can detect the angular velocity ωx.

[0024] The Y-axis angular velocity sensor element 322y includes a fixed comb electrode fixed to the base 321, a movable comb electrode that is disposed to mesh with the fixed comb electrode and is displaceable in two directions, the X-axis direction and the Z-axis direction, relative to the base 321, and a drive comb electrode that vibrates the movable comb electrode in the X-axis direction. When an angular velocity ωy about the Y-axis is applied to the Y-axis angular velocity sensor element 322y while the movable comb electrode is vibrating in the X-axis direction by energizing the drive comb electrode (drive vibration state), Coriolis force excites a detection vibration in the Z-axis direction in the movable comb electrode, and the capacitance between the fixed comb electrode and the movable comb electrode changes in response to the detection vibration. Therefore, the change in capacitance can be extracted as an output signal, and the angular velocity ωy can be detected based on the output signal. However, the configuration of the Y-axis angular velocity sensor element 322y is not particularly limited as long as it can detect the angular velocity ωy.

[0025] The Z-axis angular velocity sensor element 322z includes a fixed comb electrode fixed to the base 321, a movable comb electrode that is disposed to mesh with the fixed comb electrode and is displaceable in two directions, the X-axis and the Y-axis, relative to the base 321, and a drive comb electrode that vibrates the movable comb electrode in the X-axis direction. When an angular velocity ωz about the Z-axis is applied to the Z-axis angular velocity sensor element 322z while the movable comb electrode is vibrating in the X-axis direction by energizing the drive comb electrode (drive vibration state), Coriolis force excites a detection vibration in the Y-axis direction in the movable comb electrode, and the capacitance between the fixed comb electrode and the movable comb electrode changes in response to the detection vibration. Therefore, the change in capacitance can be extracted as an output signal, and the angular velocity ωz can be detected based on the output signal. However, the configuration of the Z-axis angular velocity sensor element 322z is not particularly limited as long as it can detect the angular velocity ωz.

[0026] Although the three-axis angular velocity sensor 32 has been described above, the configuration of the three-axis angular velocity sensor 32 is not particularly limited. For example, the base 321 and the lid 323 may be formed of a material other than silicon, such as glass. In the illustrated configuration, the sensor elements 322x, 322y, and 322z are arranged side by side along the Y-axis direction, but this arrangement is not particularly limited. The package 320 may be divided into individual sensor elements 322x, 322y, and 322z. In this case, the sensor elements 322x, 322y, and 322z may be arranged overlapping each other in the Z-axis direction. Two or more sensor elements selected from the sensor elements 322x, 322y, and 322z may be integrally formed as a single sensor element. In other words, a single sensor element may be configured to detect two or more of the angular velocities ωx, ωy, and ωz.

[0027] Furthermore, the angular velocity sensor may have either a biaxial or uniaxial angular velocity detection axis as long as it includes Z-axis angular velocity sensor element 322z, not limited to triaxial angular velocity sensor 32. In other words, it may be a biaxial angular velocity sensor with one of the X-axis and Y-axis angular velocity detection axes and the Z-axis angular velocity detection axis, or a uniaxial angular velocity sensor with only the Z-axis.

[0028] -3-axis acceleration sensor33- The three-axis acceleration sensor 33 can detect acceleration Ax in the X-axis direction, acceleration Ay in the Y-axis direction, and acceleration Az in the Z-axis direction. The three-axis acceleration sensor 33 is a silicon MEMS, just like the above-mentioned three-axis angular velocity sensor 32. Therefore, the three-axis acceleration sensor 33 can be made smaller.

[0029] 7, the three-axis acceleration sensor 33 includes a package 330 and an X-axis acceleration sensor element 332x, a Y-axis acceleration sensor element 332y, and a Z-axis acceleration sensor element 332z as first acceleration sensor elements housed in the package 330. The package 330 also includes a base 331 having a recessed portion that opens to the top surface and on which the sensor elements 332x, 332y, and 332z are arranged so as to overlap the recessed portion, and a lid 333 that is joined to the top surface of the base 331 and houses the sensor elements 332x, 332y, and 332z between the package 330 and the base 331.

[0030] Such a triaxial acceleration sensor 33 can be formed, for example, by the steps of forming a base 331 from one silicon layer (handle layer) of an SOI substrate, forming sensor elements 332x, 332y, and 332z from the other silicon layer (device layer), and bonding a lid 333 formed from a silicon substrate to the base 331. With this configuration, the triaxial acceleration sensor 33 can be manufactured using a manufacturing method that complies with silicon semiconductor processes.

[0031] The X-axis acceleration sensor element 332x, the Y-axis acceleration sensor element 332y, and the Z-axis acceleration sensor element 332z will be briefly described below.

[0032] The X-axis acceleration sensor element 332x has a fixed comb electrode fixed to the base 331 and a movable comb electrode arranged to mesh with the fixed comb electrode and movable in the X-axis direction relative to the base 331. When acceleration Ax in the X-axis direction is applied to the X-axis acceleration sensor element 332x, the movable comb electrode is displaced in the X-axis direction, and the capacitance between the fixed comb electrode and the movable comb electrode changes in response to the displacement. This change in capacitance can therefore be extracted as an output signal, and the acceleration Ax can be detected based on the output signal. However, the configuration of the X-axis acceleration sensor element 332x is not particularly limited as long as it can detect the acceleration Ax.

[0033] The Y-axis acceleration sensor element 332y has a fixed comb electrode fixed to the base 331 and a movable comb electrode arranged to mesh with the fixed comb electrode and movable in the Y-axis direction relative to the base 331. When acceleration Ay in the Y-axis direction is applied to the Y-axis acceleration sensor element 332y, the movable comb electrode is displaced in the Y-axis direction, and the capacitance between the fixed comb electrode and the movable comb electrode changes in response to the displacement. Therefore, the change in capacitance can be extracted as an output signal, and the acceleration Ay can be detected based on the output signal. However, the configuration of the Y-axis acceleration sensor element 332y is not particularly limited as long as it can detect the acceleration Ay.

[0034] The Z-axis acceleration sensor element 332z has a fixed comb electrode fixed to the base 331 and a movable comb electrode that is disposed to mesh with the fixed comb electrode and is displaceable in the Z-axis direction relative to the base 331. When acceleration Az in the Z-axis direction is applied to the Z-axis acceleration sensor element 332z, the movable comb electrode is displaced in the Z-axis direction, and the capacitance between the fixed comb electrode and the movable comb electrode changes in response to the displacement. Therefore, the change in capacitance can be extracted as an output signal, and the acceleration Az can be detected based on the output signal. However, the configuration of the Z-axis acceleration sensor element 332z is not particularly limited as long as it can detect the acceleration Az.

[0035] Although the triaxial acceleration sensor 33 has been described above, the configuration of the triaxial acceleration sensor 33 is not particularly limited. For example, the base 331 and the lid 333 may be formed of a material other than silicon, such as glass. In the illustrated configuration, the sensor elements 332x, 332y, and 332z are arranged side by side along the Y-axis direction, but their arrangement is not particularly limited. The package 330 may be divided into individual sensor elements 332x, 332y, and 332z. In this case, the sensor elements 332x, 332y, and 332z may be arranged overlapping each other in the Z-axis direction. Two or more sensor elements selected from the sensor elements 332x, 332y, and 332z may be integrally formed as a single sensor element. In other words, a single sensor element may be configured to detect two or more of the accelerations Ax, Ay, and Az. The acceleration detection axis may be two or one axis, regardless of the triaxial acceleration sensor 33.

[0036] -Circuit element 34- The circuit element 34 is electrically connected to the three-axis angular velocity sensor 32 and the three-axis acceleration sensor 33 via the substrate 31. The circuit element 34 is, for example, an MCU (Micro Controller Unit), and controls the various components of the sensor unit 3. As shown in FIGS. 4 and 5, the circuit element 34 has a control circuit section 341 that controls the driving of the three-axis angular velocity sensor 32 and the three-axis acceleration sensor 33, and an interface circuit section 342 that communicates with the circuit element 6.

[0037] Control circuit 341 controls the driving of triaxial angular velocity sensor 32, detects angular velocity ωx based on the output signal of X-axis angular velocity sensor element 322x, detects angular velocity ωy based on the output signal of Y-axis angular velocity sensor element 322y, and detects angular velocity ωz based on the output signal of Z-axis angular velocity sensor element 322z. Control circuit 341 also controls the driving of triaxial acceleration sensor 33, detects acceleration Ax based on the output signal of X-axis acceleration sensor element 332x, detects acceleration Ay based on the output signal of Y-axis acceleration sensor element 332y, and detects acceleration Az based on the output signal of Z-axis acceleration sensor element 332z.

[0038] The interface circuit section 342 transmits and receives signals, receives commands from the circuit element 6, and outputs the detected angular velocities ωx, ωy, ωz and accelerations Ax, Ay, Az to the circuit element 6. The communication method is not particularly limited, but in this embodiment, SPI (Serial Peripheral Interface) communication is used. SPI communication is a communication method suitable for connecting multiple sensors, and can output all signals related to the angular velocities ωx, ωy, ωz and accelerations Ax, Ay, Az from a single pin. This allows for fewer pins in the sensor unit 3.

[0039] The above has described the sensor unit 3. Such a sensor unit 3 is mounted face-down on the bottom surface of the third recess 211c, with the terminal surface facing downward, as shown in Fig. 2. By mounting the sensor unit 3 face-down in this way, it can be connected wirelessly to terminals (not shown) formed on the base 21, thereby making it possible to reduce the size of the inertial sensor 1.

[0040] [Angular velocity sensor element 4] Next, the angular velocity sensor element 4 will be described. As shown in FIGS. 1 and 2, the angular velocity sensor element 4 is disposed above the circuit element 6 and overlaps with the circuit element 6 in plan view from the Z-axis direction. By disposing the angular velocity sensor element 4 and the circuit element 6 so that they overlap, the planar extent of the inertial sensor 1 can be reduced, allowing for a more compact inertial sensor 1. Furthermore, because the angular velocity sensor element 4 can be disposed in a large space above the circuit element 6 and the sensor unit 3, it is easy to make the angular velocity sensor element 4 larger.

[0041] The angular velocity sensor element 4 is a quartz crystal vibrating element and can detect an angular velocity ωz around the Z axis. In other words, the angular velocity detection axis of the angular velocity sensor element 4 is the Z axis. As shown in FIG. 8 , the angular velocity sensor element 4 has a quartz crystal substrate integrally formed with: a base 40 located in the center; a pair of detection vibration arms 41 and 42 extending from the base 40 on both sides in the X axis direction; a pair of support arms 43 and 44 extending from the base 40 on both sides in the Y axis direction; a pair of drive vibration arms 45 and 46 extending from the tip of one support arm 43 on both sides in the X axis direction; and a pair of drive vibration arms 47 and 48 extending from the tip of the other support arm 44 on both sides in the X axis direction. The angular velocity sensor element 4 is supported by a support substrate 5 at the base 40.

[0042] The angular velocity detection axis of the angular velocity sensor element 4 and the angular velocity detection axis of the Z-axis angular velocity sensor element 322z are both the Z-axis, that is, the same angular velocity detection axis. Here, "the same angular velocity detection axis" refers to a state in which the angular velocity detection axis of the Z-axis angular velocity sensor element 322z relative to the angular velocity detection axis of the angular velocity sensor element 4 has an angular velocity error of ±5 degrees or less.

[0043] The angular velocity sensor element 4 also has a first detection signal electrode E1 arranged on both main surfaces of the detection vibration arm 41, a first detection ground electrode E2 arranged on both side surfaces of the detection vibration arm 41, a second detection signal electrode E3 arranged on both main surfaces of the detection vibration arm 42, a second detection ground electrode E4 arranged on both side surfaces of the detection vibration arm 42, a drive signal electrode E5 arranged on both main surfaces of the drive vibration arms 45, 46 and both side surfaces of the drive vibration arms 47, 48, and a drive ground electrode E6 arranged on both side surfaces of the drive vibration arms 45, 46 and both main surfaces of the drive vibration arms 47, 48.

[0044] The angular velocity sensor element 4 described above detects the angular velocity ωz in the following manner. When a drive signal is applied to the drive signal electrode E5, the drive vibration arms 45 and 46 and the drive vibration arms 47 and 48 flexurally vibrate in opposite phases in the Y-axis direction, as shown in FIG. 9 (hereinafter, this state is also referred to as the "drive vibration mode"). In this state, the vibration of the drive vibration arms 45 and 46 and the vibration of the drive vibration arms 47 and 48 are canceled, and the detection vibration arms 41 and 42 do not substantially vibrate. When an angular velocity ωz is applied to the angular velocity sensor element 4 while it is driven in the drive vibration mode, as shown in FIG. 10, the Coriolis force acts on the drive vibration arms 45, 46, 47, and 48, exciting flexural vibration in the X-axis direction, and the detection vibration arms 41 and 42 flexurally vibrate in the Y-axis direction in response to this flexural vibration (hereinafter, this state is also referred to as the "detection vibration mode").

[0045] The charge generated in the detection vibration arm 41 by this detection vibration mode is extracted as a first detection signal from the first detection signal electrode E1, and the charge generated in the detection vibration arm 42 is extracted as a second detection signal from the second detection signal electrode E3. The angular velocity ωz is determined based on an output signal that is a differential signal between these first and second detection signals. Note that, because the angular velocity sensor element 4 is made of a quartz crystal resonator, it can detect the angular velocity ωz with higher accuracy than the Z-axis angular velocity sensor element 322z made of silicon MEMS. One reason for this is that quartz crystal resonators have better frequency-temperature characteristics than silicon MEMS.

[0046] In particular, in this embodiment, when the bias error (static output error) of the output signal of the angular velocity sensor element 4 is Bz1 [deg / sec] and the bias error (static output error) of the output signal of the Z-axis angular velocity sensor element 322z is Bz2 [deg / sec], the relationship Bz1 < Bz2 is satisfied. Furthermore, it is preferable that the relationship Bz1 < 0.5Bz2 is satisfied, and it is more preferable that the relationship Bz1 < 0.3Bz2 is satisfied. By satisfying such a relationship, the angular velocity sensor element 4 can detect the angular velocity ωz with higher accuracy than the Z-axis angular velocity sensor element 322z.

[0047] Also, in the inertial sensor 1, the angular velocity sensor element 4 is exposed in the accommodation space S. That is, the angular velocity sensor element 4 is arranged in the accommodation space S in an exposed state. Therefore, when compared with the package 2 of the same size, the size of the angular velocity sensor element 4 can be increased compared to the configuration in which the angular velocity sensor element 4 is accommodated in the package as in the conventional case. If the size of the angular velocity sensor element 4 can be increased, a larger output signal can be obtained accordingly, the S / N is improved, and the detection accuracy of the angular velocity ωz is further enhanced. Also, because of the larger size, the dimensional error of the crystal vibration substrate becomes smaller, and the generation of spurious in the driving vibration state can be effectively suppressed. Therefore, the bias error of the output signal of the angular velocity sensor element 4 can be suppressed to be smaller. Thus, the angular velocity sensor element 4 can detect the angular velocity ωz with higher accuracy.

[0048] In this embodiment, as shown in FIG. 11 , when the length of the angular velocity sensor element 4 in the X-axis direction is Lx1 and the length of the X-axis, Y-axis, and Z-axis angular velocity sensor elements 322x, 322y, and 322z in the X-axis direction is Lx2, Lx1 > Lx2. Note that if the lengths Lx2 of the X-axis, Y-axis, and Z-axis angular velocity sensor elements 322x, 322y, and 322z are different, the largest one among them is defined as length Lx2. Also, when the length of the X-axis, Y-axis, and Z-axis acceleration sensor elements 332x, 332y, and 332z in the X-axis direction is Lx3, Lx1 > Lx3. Note that if the lengths Lx3 of the X-axis, Y-axis, and Z-axis acceleration sensor elements 332x, 332y, and 332z are different, the largest one among them is defined as length Lx3. In this way, satisfying the relationships Lx1 > Lx2 and Lx1 > Lx3 allows the angular velocity sensor element 4 to be sufficiently large in size. This allows for further improvement in the detection accuracy of the angular velocity ωz of the angular velocity sensor element 4. In particular, in this embodiment, when the length of the sensor unit 3 in the X-axis direction is Lx4, Lx1>Lx4 holds. By satisfying this relationship, the size of the angular velocity sensor element 4 can be further increased. This allows for further improvement in the detection accuracy of the angular velocity ωz of the angular velocity sensor element 4.

[0049] Furthermore, if the length of the angular velocity sensor element 4 in the Y-axis direction is Ly1 and the length of the X-axis, Y-axis, and Z-axis angular velocity sensor elements 322x, 322y, and 322z in the Y-axis direction is Ly2, then Ly1 > Ly2. If the lengths Ly2 of the X-axis, Y-axis, and Z-axis angular velocity sensor elements 322x, 322y, and 322z are different, then the largest of them is taken as length Ly2. If the length Ly3 of the X-axis, Y-axis, and Z-axis acceleration sensor elements 332x, 332y, and 332z in the Y-axis direction is Ly3, then Ly1 > Ly3. If the lengths Ly3 of the X-axis, Y-axis, and Z-axis acceleration sensor elements 332x, 332y, and 332z are different, then the largest of them is taken as length Ly3. Thus, satisfying the Ly1 > Ly2 and Ly1 > Ly3 relationships allows the angular velocity sensor element 4 to be sufficiently large in size. This allows the angular velocity sensor element 4 to detect the angular velocity ωz with even greater accuracy. In particular, in this embodiment, when the length of the sensor unit 3 in the Y-axis direction is Ly4, Ly1>Ly4 holds. By satisfying this relationship, the size of the angular velocity sensor element 4 can be further increased. This allows the angular velocity sensor element 4 to detect the angular velocity ωz with even greater accuracy.

[0050] Although the angular velocity sensor element 4 has been described above, there are no particular limitations on the arrangement or configuration of the angular velocity sensor element 4. For example, a silicon MEMS type angular velocity sensor element may be used as the angular velocity sensor element 4.

[0051] [Support substrate 5] Next, the support substrate 5 will be described. The support substrate 5 supports the angular velocity sensor element 4 and electrically connects the angular velocity sensor element 4 to a terminal (not shown) formed on the base 21. As shown in FIG. 8, the support substrate 5 is fixed to the bottom surface of the first recess 211a. The support substrate 5 is also located below the angular velocity sensor element 4, and supports the angular velocity sensor element 4 by lifting it up from below. By interposing the support substrate 5 between the base 21 and the angular velocity sensor element 4 in this way, stress is less likely to be applied to the angular velocity sensor element 4, and the angular velocity detection accuracy of the angular velocity sensor element 4 is improved.

[0052] The support substrate 5 is a substrate for TAB (Tape Automated Bonding) mounting, and as shown in FIG. 8 , includes a substrate 51 and six leads 52 provided on the substrate 51. The substrate 51 is frame-shaped when viewed from above in the Z-axis direction and has an opening 511 on the inside. The substrate 51 is made of a film made of an insulating resin such as polyimide. However, the material of the substrate 51 is not particularly limited, and it may be made of an insulating resin other than polyimide, for example. The substrate 51 has a longitudinal shape extending in the Y-axis direction and is fixed to the bottom surface of the first recess 211a at both ends in the Y-axis direction by bonding members B1. Furthermore, each lead 52 is electrically connected to a terminal (not shown) formed on the base 21 via the bonding members B1.

[0053] The six leads 52 are bonding leads that support the angular velocity sensor element 4 and are conductive wiring patterns. In this embodiment, each lead 52 is made of metal foil such as copper foil. This makes it easy to form the leads 52. Of the six leads 52, three leads 52 are arranged on the positive side of the Y axis direction with respect to the center of the substrate 51, and their tips extend into the opening 511 of the substrate 51. The remaining three leads 52 are arranged on the negative side of the Y axis direction with respect to the center of the substrate 51, and their tips extend into the opening 511 of the substrate 51.

[0054] Each of these leads 52 is bent midway in the Z-axis direction and inclined upward, with its tip passing through the opening 511 and positioned above the substrate 51. The base 40 of the angular velocity sensor element 4 is fixed to the tip of each lead 52 via a bonding member B2. Although not shown, each lead 52 is electrically connected to the corresponding electrode E1 to E6 via the bonding member B2.

[0055] Although the support substrate 5 has been described above, the configuration of the support substrate 5 is not particularly limited. For example, the support substrate 5 may be configured by etching a quartz crystal plate to form a frame and beams extending from the frame toward the center of the plate, and providing wiring patterns on the frame and beams. In this case, the angular velocity sensor element 4 is fixed near the tip of the beam of the support substrate 5 via the bonding member B2.

[0056] [Circuit element 6] 1 and 2, the circuit element 6 is mounted alongside the sensor unit 3 on the bottom surface of the third recess 211c. The circuit element 6 is electrically connected to the sensor unit 3 and the angular velocity sensor element 4 via the base 21. The circuit element 6 is, for example, an MCU (Micro Controller Unit) and controls each part of the inertial sensor 1. As shown in FIG. 12, the circuit element 6 has a control circuit section 61 that controls the driving of the angular velocity sensor element 4, a matching processing section 62 that corrects the angle error between the detection axes of the Z-axis angular velocity sensor element 322z and the angular velocity sensor element 4, and an interface circuit section 63 that communicates with an external device.

[0057] The control circuit unit 61 controls the driving of the angular velocity sensor element 4 and detects the angular velocity ωz based on the output signal of the angular velocity sensor element 4. The alignment processing unit 62 corrects the output signal of the angular velocity sensor element 4 based on the angular error of the detection axis of the angular velocity sensor element 4 relative to the detection axis of the Z-axis angular velocity sensor element 322z. In other words, the alignment correction is performed on the output signal of the angular velocity sensor element 4 so that the detection axis of the angular velocity sensor element 4 coincides with the detection axis of the Z-axis angular velocity sensor element 322z. This allows the angular velocity sensor element 4 to detect the angular velocity around the axis that coincides with the detection axis of the Z-axis angular velocity sensor element 322z.

[0058] The interface circuit unit 63 transmits and receives signals, receives commands from an external device, and outputs to the external device the angular velocities ωx, ωy, ωz and accelerations Ax, Ay, Az detected by the sensor unit 3 and the angular velocity ωz detected by the angular velocity sensor element 4. While the communication method is not particularly limited, this embodiment uses SPI (Serial Peripheral Interface) communication. SPI communication is a communication method suitable for connecting multiple sensors, and it is possible to output all signals related to the angular velocities ωx, ωy, ωz and accelerations Ax, Ay, Az from a single pin. This allows the inertial sensor 1 to have fewer pins.

[0059] In the inertial sensor 1, the angular velocity ωz is detected by both the Z-axis angular velocity sensor element 322z and the angular velocity sensor element 4. As described above, the angular velocity sensor element 4 detects the angular velocity ωz with higher accuracy than the Z-axis angular velocity sensor element 322z. Therefore, the interface circuit unit 63 may bundle together a total of six signals, including the angular velocity ωx, ωy and acceleration Ax, Ay, and Az detected by the sensor unit 3 and the angular velocity ωz detected by the angular velocity sensor element 4, and output them to an external device, without outputting the angular velocity ωz detected by the Z-axis angular velocity sensor element 322z to an external device. Alternatively, the interface circuit unit 63 may bundle together a total of seven signals, including the angular velocity ωx, ωy, ωz and acceleration Ax, Ay, and Az detected by the sensor unit 3 and the angular velocity ωz detected by the angular velocity sensor element 4, and output them to an external device. In this case, the user can decide whether to use the angular velocity ωz detected by Z-axis angular velocity sensor element 322z, the angular velocity ωz detected by angular velocity sensor element 4, or both angular velocities ωz. Furthermore, by having two sensors, angular velocity sensor element 4 and Z-axis angular velocity sensor element 322z, that detect angular velocity around the Z axis, even if one of the two sensors that detect angular velocity around the Z axis fails, the other can still detect angular velocity around the Z axis. This improves the robustness of angular velocity detection around the Z axis.

[0060] The above describes the inertial sensor 1. As described above, the inertial sensor 1 includes a package 2 having an accommodation space S, a sensor unit 3 disposed in the accommodation space S and including X-axis, Y-axis, and Z-axis acceleration sensor elements 332x, 332y, and 332z as first acceleration sensor elements and X-axis, Y-axis, and Z-axis angular velocity sensor elements 322x, 322y, and 322z as first angular velocity sensor elements, an angular velocity sensor element 4 disposed in the accommodation space S in an exposed state and serving as a second angular velocity sensor element whose angular velocity detection axis is the same as that of the Z-axis angular velocity sensor element 322z, and a circuit element 6 disposed in the accommodation space S and electrically connected to the sensor unit 3 and the angular velocity sensor element 4. With this configuration, the angular velocity sensor element 4 is exposed in the accommodation space S. Therefore, when compared with a package 2 of the same size, the size of the angular velocity sensor element 4 can be made larger than in a conventional configuration in which the angular velocity sensor element 4 is housed in a package. As a result, the angular velocity sensor element 4 can detect the angular velocity ωz with higher accuracy.

[0061] As described above, the angular velocity sensor element 4 is arranged to overlap at least one of the sensor unit 3 and the circuit element 6 in a plan view taken along the Z-axis, which is the angular velocity detection axis. In this embodiment, the angular velocity sensor element 4 is arranged to overlap the circuit element 6. This configuration can reduce the planar extent of the inertial sensor 1, thereby enabling the inertial sensor 1 to be made smaller. Furthermore, since the angular velocity sensor element 4 can be arranged in a large space above the circuit element 6, it is easy to make the angular velocity sensor element 4 larger.

[0062] As described above, the angular velocity sensor element 4 is supported by the package 2 via the support substrate 5. With this configuration, stress is less likely to be applied to the angular velocity sensor element 4, and the angular velocity detection accuracy of the angular velocity sensor element 4 is improved.

[0063] Furthermore, as described above, when the X-axis direction is defined as the first axis direction and the Y-axis direction is defined as the second axis direction, which are orthogonal to the Z-axis and perpendicular to each other, the length Lx1 of the angular velocity sensor element 4 in the X-axis direction is greater than the length Lx2 of the X-axis, Y-axis, and Z-axis angular velocity sensor elements 322x, 322y, and 322z in the X-axis direction. This configuration allows the angular velocity sensor element 4 to be sufficiently large. As a result, the detection accuracy of the angular velocity ωz by the angular velocity sensor element 4 can be further improved.

[0064] As described above, the length Ly1 of the angular velocity sensor element 4 in the Y-axis direction is greater than the length Ly2 of the X-axis, Y-axis, and Z-axis angular velocity sensor elements 322x, 322y, and 322z in the Y-axis direction. This configuration allows the angular velocity sensor element 4 to be sufficiently large in size. This further improves the detection accuracy of the angular velocity ωz of the angular velocity sensor element 4.

[0065] As described above, the length Lx1 of the angular velocity sensor element 4 in the X-axis direction is greater than the length Lx3 of the X-axis, Y-axis, and Z-axis acceleration sensor elements 332x, 332y, and 332z in the X-axis direction. This configuration allows the angular velocity sensor element 4 to be sufficiently large in size. This further improves the detection accuracy of the angular velocity ωz of the angular velocity sensor element 4.

[0066] As described above, the length Ly1 of the angular velocity sensor element 4 in the Y-axis direction is greater than the length Ly3 of the X-axis, Y-axis, and Z-axis acceleration sensor elements 332x, 332y, and 332z in the Y-axis direction. This configuration allows the angular velocity sensor element 4 to be sufficiently large in size. This further improves the accuracy with which the angular velocity sensor element 4 detects the angular velocity ωz.

[0067] As described above, the accommodation space S is decompressed. With this configuration, the viscous resistance in the accommodation space S is reduced, and the vibration characteristics of the angular velocity sensor element 4 are improved.

[0068] Furthermore, as described above, the bias error Bz1 of the output signal of the angular velocity sensor element 4 is smaller than the bias error Bz2 of the output signal of the Z-axis angular velocity sensor element 322z. With this configuration, the angular velocity sensor element 4 can detect the angular velocity ωz with higher accuracy than the Z-axis angular velocity sensor element 322z.

[0069] As described above, the circuit element 6 also has a matching processing unit 62 that corrects the angular error between the angular velocity detection axes of the Z-axis angular velocity sensor element 322z and the angular velocity sensor element 4. With this configuration, the angular velocity sensor element 4 can detect the angular velocity around the axis that coincides with the detection axis of the Z-axis angular velocity sensor element 322z.

[0070] As described above, the sensor unit 3 includes three first acceleration sensor elements: X-axis, Y-axis, and Z-axis acceleration sensor elements 332x, 332y, and 332z, whose acceleration detection axes are orthogonal to each other; and three first angular velocity sensor elements: X-axis, Y-axis, and Z-axis angular velocity sensor elements 322x, 322y, and 322z, whose angular velocity detection axes are orthogonal to each other. The angular velocity detection axis of the angular velocity sensor element 4 is the same as the angular velocity detection axis of any one of the X-axis, Y-axis, and Z-axis angular velocity sensor elements 322x, 322y, and 322z—in this embodiment, the angular velocity detection axis of the Z-axis angular velocity sensor element 322z. This configuration allows inertia to be detected along a total of six axes, with angular velocity about the Z axis being detected with particularly high accuracy, resulting in a highly convenient inertial sensor 1.

[0071] The inertial sensor 1 of this embodiment has been described above. However, the configuration of the inertial sensor 1 is not particularly limited.

[0072] 13, the sensor unit 3 may be mounted face-up on the bottom surface of the third recess 211c with the terminal surface facing upward. In this case, the sensor unit 3 is electrically connected to a terminal arranged on the base 21 via a bonding wire (not shown).

[0073] 14, the sensor unit 3 may be mounted face-down on the top surface of the circuit element 6 with the terminal surface facing downward. With this configuration, the size of the circuit element 6 can be increased compared to this embodiment. This allows the circuit element 6 to have higher performance and more functions. Note that, as shown in FIG. 15, the sensor unit 3 may be inverted from the configuration of FIG. 14 and mounted face-up on the top surface of the circuit element 6 with the terminal surface facing upward.

[0074] 16, for example, the sensor unit 3 may be mounted face-down on the upper surface of the circuit element 6 with the terminal surface facing downward, and the angular velocity sensor element 4 may be disposed above the sensor unit 3. With this configuration, the angular velocity sensor element 4, support substrate 5, sensor unit 3, and circuit element 6 can be disposed in a stacked manner, which reduces the planar extent of the inertial sensor 1 compared to this embodiment and enables the inertial sensor 1 to be made more compact. Note that, as shown in FIG. 17, the sensor unit 3 may be inverted from the configuration of FIG. 16 and mounted face-up on the upper surface of the circuit element 6 with the terminal surface facing upward.

[0075] 18, for example, the circuit element 6 may be mounted on the upper surface of the sensor unit 3, and the angular velocity sensor element 4 may be disposed above the circuit element 6. With this configuration, the angular velocity sensor element 4, the support substrate 5, the sensor unit 3, and the circuit element 6 can be disposed in a stacked manner, which reduces the planar extent of the inertial sensor 1 compared to this embodiment, thereby enabling the inertial sensor 1 to be made smaller.

[0076] Second Embodiment FIG. 19 is a schematic view showing a vehicle according to the second embodiment.

[0077] As shown in Fig. 19, the vehicle 100 of this embodiment is an automobile. However, the vehicle 100 is not limited to an automobile, and may be, for example, an agricultural machine such as a tractor or a construction machine such as a backhoe.

[0078] The vehicle 100 is also equipped with an inertial sensor 1. The inertial sensor 1 is oriented such that its X-axis is oriented in the longitudinal direction of the vehicle 100, its Y-axis is oriented in the lateral direction of the vehicle 100, and its Z-axis is oriented in the vertical direction of the vehicle 100. Therefore, the X-axis of the inertial sensor 1 coincides with the roll axis of the vehicle 100, its Y-axis coincides with the pitch axis of the vehicle 100, and its Z-axis coincides with the yaw axis of the vehicle 100. Therefore, the orientation of the vehicle 100 is expressed by the roll angle around the X-axis, the pitch angle around the Y-axis, and the yaw angle around the Z-axis. The roll angle corresponds to the tilt of the vehicle 100 in the lateral direction, the pitch angle corresponds to the tilt of the vehicle 100 in the longitudinal direction, and the yaw angle corresponds to the change in the direction of travel or the orientation of the vehicle 100.

[0079] Here, for example, in various types of control of the vehicle 100, such as autonomous driving, the most important of the roll angle, pitch angle, and yaw angle is the yaw angle, which corresponds to the change in direction or orientation of the vehicle 100. This is because a detection error in the yaw angle (the difference between the actual value and the measured value) directly correlates with the vehicle 100's heading error (the difference between the actual heading and the measured heading), whereas errors in the roll angle and pitch angle do not directly correlate with the vehicle 100's heading error. In order to reduce the heading error of the vehicle 100, it is effective to further improve the accuracy of the yaw angle detection. Of course, it is best to use a sensor that can detect all of the roll angle, pitch angle, and yaw angle with high accuracy, but this results in increased sensor size and cost. In this regard, the inertial sensor 1, which can detect the yaw angle with particularly high accuracy using the angular velocity sensor element 4 and can also detect the roll angle and pitch angle with sufficient accuracy using the sensor unit 3, can effectively contribute to reducing the heading error of the vehicle 100 while achieving a smaller device size and lower costs. Therefore, the inertial sensor 1 is highly compatible with the vehicle 100 and has a high affinity.

[0080] As described above, the vehicle 100 is provided with the inertial sensor 1, and the Z axis, which is the angular velocity detection axis, is aligned with the yaw axis. With this configuration, the traveling direction error of the vehicle 100 can be effectively reduced.

[0081] The second embodiment can also achieve the same effects as the first embodiment described above.

[0082] While the inertial sensor and vehicle of the present invention have been described above based on the illustrated embodiment, the present invention is not limited to this, and the configuration of each part can be replaced with any configuration having a similar function. Furthermore, any other configuration may be added to the present invention. Furthermore, each embodiment and modified example may be combined as appropriate. [Explanation of symbols]

[0083] 1...inertial sensor, 100...vehicle, 2...package, 21...base, 211...recess, 211a...first recess, 211b...second recess, 211c...third recess, 22...lid, 221...groove, 23...seam ring, 3...sensor unit, 30...lead, 31...substrate, 32...3-axis angular velocity sensor, 320...package, 321...base, 322x...X-axis angular velocity sensor element, 322y...Y-axis angular velocity sensor element, 322z...Z-axis angular velocity sensor element, 323...lid, 33...3-axis acceleration sensor, 330...package, 331...base, 332x...X-axis acceleration sensor element, 332y...Y-axis acceleration sensor element, 332z...Z-axis acceleration sensor element, 333...lid, 34...circuit element, 341...control circuit section, 342... Interface circuit unit, 35...molding member, 4...angular velocity sensor element, 40...base, 41...detection vibration arm, 42...detection vibration arm, 43...support arm, 44...support arm, 45...drive vibration arm, 46...drive vibration arm, 47...drive vibration arm, 48...drive vibration arm, 5...support substrate, 51...substrate, 511...opening, 52...lead, 6...circuit element, 61...control circuit unit, 62...matching processing unit, 63...interface circuit unit, Ax...acceleration, Ay...acceleration, Az...acceleration, B1...joint member, B2...joint member, E1...first detection signal electrode, E2...first detection ground electrode, E3...second detection signal electrode, E4...second detection ground electrode, E5...drive signal electrode, E6...drive ground electrode, EL...energy ray, S...accommodation space, ωx...angular velocity, ωy...angular velocity, ωz...angular velocity

Claims

1. a package having a storage space; a sensor unit disposed in the accommodation space and including a first acceleration sensor element and a first angular velocity sensor element; a second angular velocity sensor element disposed in the accommodation space in an exposed state and having an angular velocity detection axis identical to that of the first angular velocity sensor element; a circuit element disposed in the accommodation space and electrically connected to the sensor unit and the second angular velocity sensor element.

2. The inertial sensor according to claim 1 , wherein the second angular velocity sensor element is disposed so as to overlap with at least one of the sensor unit and the circuit element in a plan view along the angular velocity detection axis.

3. The inertial sensor according to claim 2 , wherein the second angular velocity sensor element is supported by the package via a support substrate.

4. When directions that are orthogonal to the angular velocity detection axis and are orthogonal to each other are defined as first axis directions and second axis directions, The inertial sensor according to claim 1 , wherein the length of the second angular velocity sensor element in the first axial direction is greater than the length of the first angular velocity sensor element in the first axial direction.

5. The inertial sensor according to claim 4 , wherein the length of the second angular velocity sensor element in the second axial direction is greater than the length of the first angular velocity sensor element in the second axial direction.

6. The inertial sensor according to claim 4 , wherein the length of the second angular velocity sensor element in the first axial direction is greater than the length of the first acceleration sensor element in the first axial direction.

7. The inertial sensor according to claim 4 , wherein the length of the second angular velocity sensor element in the second axial direction is greater than the length of the first acceleration sensor element in the second axial direction.

8. The inertial sensor according to claim 1 , wherein the accommodation space is depressurized.

9. The inertial sensor according to claim 1 , wherein a bias error of the output signal of the second angular velocity sensor element is smaller than a bias error of the output signal of the first angular velocity sensor element.

10. The inertial sensor according to claim 1 , wherein the circuit element includes a matching processing unit that corrects an angular error between the first angular velocity sensor element and the second angular velocity sensor element with respect to the angular velocity detection axis.

11. the sensor unit includes three first acceleration sensor elements arranged so that acceleration detection axes are orthogonal to one another, and three first angular velocity sensor elements arranged so that angular velocity detection axes are orthogonal to one another, The inertial sensor according to claim 1 , wherein the angular velocity detection axis of the second angular velocity sensor element is the same as the angular velocity detection axis of any one of the first angular velocity sensor elements.

12. An inertial sensor according to any one of claims 1 to 11, A vehicle characterized in that the angular velocity detection axis is along the yaw axis.

Images