Inertial measurement unit

Abstract

To reduce mutual influence of vibration in a plurality of inertial sensors arranged on the same substrate.SOLUTION: An inertial measurement device is provided with a substrate, a container for containing the substrate, a first fixing member and a second fixing member for fixing the substrate to the container, a first sensor which is arranged on the substrate and detects a physical quantity along a vertical axis with respect to the substrate, and a second sensor arranged on the substrate, wherein the first sensor, the first fixing member and the second fixing member, and the second sensor are arranged in order in a first direction parallel to the substrate, and the second sensor detects a physical quantity along a second axis perpendicular to the first axis, and, the second sensor is separated from the first sensor by a region between the first fixing member and the second fixing member when viewed in the direction along the vertical axis.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to inertial measurement units. [Background technology]

[0002] Inertial measurement units having multiple inertial sensors are known. In the inertial measurement unit described in Patent Document 1, the multiple inertial sensors are arranged on a substrate. In this case, the multiple inertial sensors are susceptible to the influence of each other's vibrations. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-175166 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to reduce the influence of vibrations on multiple inertial sensors arranged on the same board, it is necessary to pair all the inertial sensors on the board so that the frequency difference between their natural frequencies falls outside the measurement band. [Means for solving the problem]

[0005] The inertial measurement unit of the present disclosure comprises a substrate, a container for accommodating the substrate, first and second fixing members that respectively fix the substrate to the container, a first sensor disposed on the substrate and detecting a physical quantity along an axis perpendicular to the substrate, and a second sensor disposed on the substrate, wherein the first sensor, the first and second fixing members, and the second sensor are disposed in order in a first direction along a first axis parallel to the substrate, the second sensor detects a physical quantity along a second axis parallel to the substrate and perpendicular to the first axis, and the second sensor is separated from the first sensor by a region between the first and second fixing members when viewed in the direction along the vertical axis. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a diagram showing the external configuration of an inertial measurement unit. [Figure 2] FIG. 2 is an exploded perspective view of the inertial measurement unit. [Figure 3] FIG. 1 is a diagram showing a schematic configuration of an inertial measurement unit. [Figure 4] FIG. 2 is a diagram showing a schematic configuration of a container. [Figure 5] FIG. 2 is a diagram showing a schematic configuration of a circuit board. [Figure 6] FIG. 1 is a diagram showing a schematic configuration of an inertial sensor. [Figure 7] FIG. 2 is a diagram showing a schematic configuration of a sensor element. [Figure 8] FIG. 2 is a diagram showing an example of the configuration of a circuit board. [Figure 9] FIG. 2 is a diagram showing an example of the configuration of a circuit board. [Figure 10] FIG. 2 is a diagram showing an example of the configuration of a circuit board. [Figure 11] FIG. 2 is a diagram showing an example of the configuration of a circuit board. [Figure 12] FIG. 2 is a diagram showing an example of the configuration of a circuit board. [Figure 13] FIG. 2 is a diagram showing an example of the configuration of a circuit board. DETAILED DESCRIPTION OF THE INVENTION

[0007] FIG. 1 shows the external configuration of an inertial measurement unit 1. The inertial measurement unit 1 is a measurement device that measures a physical quantity by utilizing inertia. As an example, the inertial measurement unit 1 measures acceleration as a physical quantity. However, the inertial measurement unit 1 may measure a physical quantity other than acceleration.

[0008] The inertial measurement unit 1 shown in FIG. 1 has a rectangular parallelepiped shape with a width W, a depth D, and a height H. The width W is the length along the long sides of the inertial measurement unit 1. The depth D is the length along the short sides of the inertial measurement unit 1. The height H is the length along the sides perpendicular to the long and short sides. The exterior of the inertial measurement unit 1 is made up of a container 11 and a lid 21.

[0009] Several figures, including FIG. 1, show an XYZ coordinate system. The X axis is an axis along the long side of the inertial measurement unit 1. The +X direction is the direction from left to right of the long side of the inertial measurement unit 1 shown in FIG. 1. The -X direction is the direction from right to left of the long side of the inertial measurement unit 1 shown in FIG. 1. The Y axis is an axis along the short side of the inertial measurement unit 1. The +Y direction is the direction from the front to the back of the short side of the inertial measurement unit 1 shown in FIG. 1. The -Y direction is the direction from the back to the front of the short side of the inertial measurement unit 1 shown in FIG. 1. The Z axis is an axis along a side of the inertial measurement unit 1 that is perpendicular to the long and short sides. The +Z direction is the direction from bottom to top of the inertial measurement unit 1 shown in FIG. 1. The -Z direction is the direction from top to bottom of the inertial measurement unit 1 shown in FIG. 1.

[0010] The container 11 houses a circuit board 31, which will be described later. The container 11 is a box-shaped body with an opening in the -Z direction. The container 11 forms part of the exterior housing of the inertial measurement unit 1. The container 11 is made of a metal material such as aluminum. The container 11 has a bottom 11a and side portions 11b. The bottom 11a is, for example, formed in a flat plate shape. The bottom 11a is provided with screw holes 13 and an opening 15. The side portions 11b are frame-shaped members extending in the -Z direction from the outer periphery of the bottom 11a.

[0011] The screw holes 13 are provided on the outer periphery of the inertial measurement unit 1. The inertial measurement unit 1 shown in FIG. 1 has three screw holes 13. The three screw holes 13 are provided at two corners and the center of the long sides of the inertial measurement unit 1. Fixing screws (not shown) are inserted into the screw holes 13. The inertial measurement unit 1 is fixed to the mounting surface of the mounting body by the fixing screws. The inertial measurement unit 1 is used in a state where it is directly or indirectly fixed to the mounting surface of the mounting body. The mounting body is a structure such as a building, bridge, or machine. The structure may also be a moving body such as an automobile, drone, robot, or ship.

[0012] A connector 33, which will be described later, is inserted into the opening 15. The connector 33 is provided on a circuit board 31 housed in the container 11. The opening 15 allows the connector 33 provided on the circuit board 31 to be accessible to the outside of the container 11.

[0013] The lid portion 21 is attached to a position in the -Z direction of the container 11. The lid portion 21 covers the opening of the container 11 in the -Z direction. The lid portion 21 may be attached directly to the container 11 or may be attached via a sealing member (not shown).

[0014] Fig. 2 shows an exploded perspective view of the inertial measurement unit 1. Fig. 2 shows the disassembled state of the inertial measurement unit 1. The inertial measurement unit 1 is disassembled into a container 11, a lid 21, and a first circuit board 31a which is an example of a circuit board 31.

[0015] The container 11 has a bottom 11a with an opening 15, and a side 11b with an inner surface 11c and a support surface 11d. The container 11 is provided with a screw hole 13, a fixing protrusion 17, and a screw hole 19 for fixing a lid.

[0016] The inner surface 11c is the inner peripheral surface of the side portion 11b. The support surface 11d is the end surface of the side portion 11b in the -Z direction. The support surface 11d faces the lid portion 21. The support surface 11d supports the lid portion 21.

[0017] The fixing protrusions 17 are provided on the support surface 11d. In the container 11 shown in Fig. 2, three fixing protrusions 17 are provided on the support surface 11d. The fixing protrusions 17 protrude in the -Z direction from the support surface 11d. A screw hole 13 is formed in each of the three fixing protrusions 17.

[0018] The lid fixing screw holes 19 are provided in the support surface 11d. The container 11 shown in Fig. 2 has three lid fixing screw holes 19 provided in the support surface 11d. The three lid fixing screw holes 19 are provided at the corners and the center of the long sides of the container 11. Lid fixing screws 41 are inserted into the lid fixing screw holes 19.

[0019] The container 11 shown in Fig. 2 has a rectangular shape when viewed from the +Z direction, but is not limited to this. The container 11 shown in Fig. 2 may have a polygonal shape such as a square, hexagon, or octagon when viewed from the +Z direction. The external shape of the container 11 can be set as appropriate.

[0020] Three through holes 23 are formed in the lid portion 21. The through holes 23 are formed at positions corresponding to the lid fixing screw holes 19 when the lid portion 21 is attached to the container 11. A lid fixing screw 41 is inserted into each of the three through holes 23. The lid portion 21 is attached to the container 11 by the lid fixing screws 41.

[0021] The circuit board 31 is housed in the container 11. The circuit board 31 is a multilayer board in which a plurality of through holes and the like are formed. For example, the circuit board 31 is made of a glass epoxy board. The circuit board 31 may also be made of a composite board, a ceramic board, or the like. The circuit board 31 carries a connector 33, a processing circuit 35 (not shown in FIG. 2), and a plurality of inertial sensors 100. The processing circuit 35 and the inertial sensors 100 will be described later. The first circuit board 31a shown in FIG. 2 carries a first inertial sensor 101, a second inertial sensor 102, a third inertial sensor 103, a fourth inertial sensor 104, a fifth inertial sensor 105, and a sixth inertial sensor 106 as the plurality of inertial sensors 100. The fourth inertial sensor 104 is not shown in FIG. 2. The circuit boards 31, such as the first circuit board 31a, correspond to an example of a board.

[0022] Fig. 3 shows a schematic configuration of the inertial measurement unit 1. Fig. 3 shows an XZ cross section of the approximate center along the Y axis of the inertial measurement unit 1. Fig. 3 shows the layout and cross-sectional configuration of a first circuit board 31a, which is an example of the circuit board 31.

[0023] Electronic components and the like (not shown) are mounted on the first circuit board 31a. The processing circuit 35, the six inertial sensors 100, and the connector 33 mounted on the first circuit board 31a are electrically connected via wiring (not shown).

[0024] The first circuit board 31a has a first surface S1 and a second surface S2. The first surface S1 is the surface of the first circuit board 31a facing in the -Z direction. The second surface S2 is the surface of the first circuit board 31a facing in the +Z direction. The first circuit board 31a comes into contact with the container 11 at the second surface S2 and is supported by the container 11.

[0025] The first surface S1 is provided with a first inertial sensor 101, a second inertial sensor 102 (not shown), a third inertial sensor 103, a fifth inertial sensor 105, and a sixth inertial sensor 106. The second surface S2 is provided with a connector 33, a processing circuit 35, and a fourth inertial sensor 104. The fourth inertial sensor 104 is disposed opposite the first inertial sensor 101 with the first circuit board 31a interposed therebetween.

[0026] The connector 33 is connected to an external device. The connector 33 inputs a drive voltage from the external device. The connector 33 outputs various signals to the external device. The connector 33 is, for example, a plug having multiple pins. The external device has a socket that connects to the plug.

[0027] The processing circuit 35 controls each part of the inertial measurement unit 1. The processing circuit 35 receives detection values ​​from each inertial sensor 100. The processing circuit 35 outputs data calculated using the detection values ​​as a signal. An example of the processing circuit 35 is an MCU (Micro Controller Unit). The processing circuit 35 has a storage medium such as a non-volatile memory and an A / D converter. The storage medium stores a program that operates the inertial measurement unit 1. The processing circuit 35 corresponds to an example of a control circuit.

[0028] Fig. 4 shows a schematic configuration of the container 11. Fig. 4 shows a plan view of the container 11 from the -Z direction. Fig. 4 shows the internal configuration of the container 11. Fig. 4 virtually shows the first fixing member 51, the second fixing member 53, and the connector fixing member 55.

[0029] The container 11 has a first base 11e, a second base 11f, a third base 11g, and two protrusions 11h.

[0030] The first pedestal 11e is provided inside the container 11. The first pedestal 11e is provided at a position in the -Y direction inside the container 11. The first pedestal 11e is provided at a position in contact with the inner surface 11c of the side portion 11b. The first pedestal 11e supports the circuit board 31 at a position in the -Y direction. The first pedestal 11e is provided at an intermediate position of the container 11 along the X axis inside the container 11. The first pedestal 11e supports the circuit board 31 at an intermediate position of the container 11 along the X axis inside the container 11.

[0031] The second pedestal 11f is provided inside the container 11. The second pedestal 11f is provided at a position in the +Y direction inside the container 11. The second pedestal 11f is provided at a position in contact with the inner surface 11c of the side portion 11b. The second pedestal 11f supports the circuit board 31 at a position in the +Y direction. The second pedestal 11f is provided at an intermediate position of the container 11 along the X axis inside the container 11. The second pedestal 11f supports the circuit board 31 at an intermediate position of the container 11 along the X axis inside the container 11.

[0032] The third pedestal 11g is provided on the outer periphery of the opening 15. The third pedestal 11g is provided at a position in the -X direction inside the container 11. The third pedestal 11g supports the circuit board 31 at a position in the -X direction inside the container 11. The first pedestal 11e, the second pedestal 11f, and the third pedestal 11g each support the circuit board 31 parallel to the XY plane on a surface facing the -Z direction.

[0033] The protrusions 11h are portions that protrude from the side portions 11b toward the inside of the container 11. The protrusions 11h are formed in a ridge shape at a position extending from the bottom portion 11a to the support surface 11d in the -Z direction. One of the two protrusions 11h is provided at approximately the center of the long side of the side portion 11b in the -Y direction. The other of the two protrusions 11h is provided at approximately the center of the long side of the side portion 11b in the +Y direction. The two protrusions 11h are formed in a shape that corresponds to the outer peripheral shape of the circuit board 31.

[0034] The first fixing member 51 fixes the circuit board 31 to the container 11. The first fixing member 51 shown in FIG. 4 is disposed on the first base 11e. The first fixing member 51 fixes the circuit board 31 to the first base 11e of the container 11. The first fixing member 51 is, for example, an adhesive. The first fixing member 51 is not limited to an adhesive. The configuration of the first fixing member 51 is not limited as long as it is capable of fixing the circuit board 31 to the container 11.

[0035] The second fixing member 53 fixes the circuit board 31 to the container 11. The second fixing member 53 shown in FIG. 4 is disposed on the second base 11f. The second fixing member 53 fixes the circuit board 31 to the second base 11f of the container 11. The second fixing member 53 is, for example, an adhesive. The second fixing member 53 is not limited to an adhesive. The configuration of the second fixing member 53 is not limited as long as it is capable of fixing the circuit board 31 to the container 11.

[0036] The connector fixing member 55 fixes the circuit board 31 to the container 11. The connector fixing member 55 is arranged in a ring shape at the outer periphery of the opening 15. The connector fixing member 55 fixes the circuit board 31 to the third seat 11g of the container 11. One example of the connector fixing member 55 is an adhesive. The connector fixing member 55 is not limited to an adhesive. The configuration of the connector fixing member 55 is not limited as long as it is capable of fixing the circuit board 31 to the container 11.

[0037] Fig. 5 is a perspective view showing a schematic configuration of a first circuit board 31a, which is an example of the circuit board 31. Fig. 5 shows the configuration on a first surface S1 of the first circuit board 31a. Six inertial sensors 100 are mounted on the first circuit board 31a.

[0038] The inertial sensor 100 detects a physical quantity by utilizing inertia. The inertial sensor 100 mounted on the inertial measurement unit 1 is an acceleration sensor that detects acceleration along one axis as a physical quantity. The inertial sensor 100 mounted on the inertial measurement unit 1 is not limited to an acceleration sensor. The inertial sensor 100 may be an angular velocity sensor. The inertial sensor 100 may also be a sensor that detects multi-axial physical quantities along two or more axes.

[0039] The first inertial sensor 101 and the fourth inertial sensor 104 are disposed opposite each other. The second inertial sensor 102 and the fifth inertial sensor 105 are disposed opposite each other. The third inertial sensor 103 and the sixth inertial sensor 106 are disposed opposite each other.

[0040] The first inertial sensor 101 detects a first detection value, whose positive value is a positive acceleration in a first detection direction D1. The first detection direction D1 is a direction along the Z axis. The first detection direction D1 corresponds to the -Z direction. The first detection value is a Z-axis acceleration detection value that indicates an acceleration component parallel to the Z axis. The fourth inertial sensor 104 detects a fourth detection value, whose positive value is a positive acceleration in a fourth detection direction D4. The fourth detection direction D4 is a direction along the Z axis. The fourth detection direction D4 corresponds to the +Z direction. The first detection direction D1 and the fourth detection direction D4 are opposite directions. The fourth detection value is a Z-axis acceleration detection value that is in opposite phase to the first detection value.

[0041] The second inertial sensor 102 detects a second detection value, the positive value of which is a positive acceleration in a second detection direction D2. The second detection direction D2 is a direction along the Y-axis. The second detection direction D2 corresponds to the +Y direction. The second detection value is a Y-axis acceleration detection value that indicates an acceleration component parallel to the Y-axis. The fifth inertial sensor 105 detects a fifth detection value, the positive value of which is a positive acceleration in a fifth detection direction D5. The fifth detection direction D5 is a direction along the Y-axis. The fifth detection direction D5 corresponds to the -Y direction. The second detection direction D2 and the fifth detection direction D5 are opposite directions. The fifth detection value is a Y-axis acceleration detection value that is in phase opposite to the second detection value.

[0042] The third inertial sensor 103 detects a third detection value, whose positive value is a positive acceleration in a third detection direction D3. The third detection direction D3 is a direction along the X-axis. The third detection direction D3 corresponds to the +X direction. The third detection value is an X-axis acceleration detection value that indicates an acceleration component parallel to the X-axis. The sixth inertial sensor 106 detects a sixth detection value, whose positive value is a positive acceleration in a sixth detection direction D6. The sixth detection direction D6 is a direction along the X-axis. The sixth detection direction D6 corresponds to the -X direction. The third detection direction D3 and the sixth detection direction D6 are opposite directions. The sixth detection value is an X-axis acceleration detection value that is in opposite phase to the third detection value.

[0043] 6 shows a schematic configuration of the inertial sensor 100. FIG. 6 shows a cross section of the inertial sensor 100.

[0044] FIG. 6 and FIG. 7, which will be described later, show an ABC coordinate system. The ABC coordinate system is a local coordinate system that indicates each axis of the inertial sensor 100. The A-axis and B-axis are axes parallel to the plane of a flat substrate structure 201, which will be described later. The A-axis and B-axis are orthogonal to each other. The B-axis is an axis parallel to the extension direction of a vibration element 270, which will be described later. The +B direction is a direction from right to left of the inertial sensor 100 shown in FIG. 6. The -B direction is a direction from left to right of the inertial sensor 100 shown in FIG. 6. The A-axis is an axis orthogonal to the extension direction of the vibration element 270. The +A direction is a direction from the back to the front of the inertial sensor 100 shown in FIG. 6. The -A direction is a direction from the front to the back of the inertial sensor 100 shown in FIG. 6. The C-axis is an axis orthogonal to the A-axis and B-axis. The +C direction is a direction from bottom to top of the inertial sensor 100 shown in FIG. 6. The −C direction is the direction from top to bottom of the inertial sensor 100 shown in FIG.

[0045] The inertial sensor 100 includes a sensor element 200 and a package 110. The inertial sensor 100 accommodates the sensor element 200 in an accommodating space 111 formed by the package 110.

[0046] The package 110 is a housing that defines an accommodation space 111. The package 110 has a package base 120 and a lid 130. The accommodation space 111 is covered by the package base 120 and the lid 130.

[0047] The package base 120 is a box-shaped body having an opening in the +C direction. The package base 120 has an inner side surface 120a, an inner bottom surface 120b, a step portion 120c, and an outer bottom surface 120d. The inner side surface 120a and the inner bottom surface 120b are internal surfaces of the package base 120. The outer bottom surface 120d is an outer surface of the package base 120. The package base 120 has external terminals 145.

[0048] The step portion 120c is formed inside the package base 120. The step portion 120c is provided in a frame shape along the inner side surface 120a. The step portion 120c is a portion that protrudes in the +C direction from the inner bottom surface 120b. A plurality of internal terminals 140 are provided on the step portion 120c.

[0049] The multiple internal terminals 140 are connected to fixed portion connection terminals 225 provided on the first support portion 230, the second support portion 240, the third support portion 250, and the fourth support portion 260 of the sensor element 200, respectively. The first support portion 230, the second support portion 240, the third support portion 250, and the fourth support portion 260 will be described later. The internal terminals 140 and the fixed portion connection terminals 225 are electrically and mechanically connected via a conductive adhesive 141.

[0050] The external terminal 145 is provided on the outer bottom surface 120d. The external terminal 145 is electrically connected to the internal terminal 140 via internal wiring (not shown). The external terminal 145 is electrically connected to the inertial sensor 100 via wiring provided on the circuit board 31. The external terminal 145 may be provided on an outer surface of the package base 120 different from the outer bottom surface 120d.

[0051] The lid 130 is a flat plate-shaped member. The lid 130 closes the opening of the package base 120. The lid 130 is attached to the package base 120 via a lid joining member 132. By closing the opening of the package base 120 with the lid 130, the accommodation space 111 in which the sensor element 200 is accommodated is airtightly sealed.

[0052] 7 shows a schematic configuration of the sensor element 200. 7 shows a perspective view of the sensor element 200. The sensor element 200 has a substrate structure 201, a vibration element 270, and a mass portion 280.

[0053] The substrate structure 201 is flat and has a main surface parallel to the AB plane. The substrate structure 201 includes a base 210, a movable portion 214, a connecting portion 220, and a plurality of support portions. The plurality of support portions are a first support portion 230, a second support portion 240, a third support portion 250, and a fourth support portion 260. The number of support portions may be two or three. As an example, the substrate structure 201 is made of a quartz substrate. The substrate structure 201 may also be made of a material other than quartz.

[0054] The base 210 is connected to the movable part 214 via a groove-shaped joint part 212 along the A axis. The base 210 supports the movable part 214 so that it can swing. The base 210 has a U-shape bent at a right angle in a plan view from the +C direction. The connecting part 220 connects both ends of the U-shape formed by the base 210 along the A axis in the +B direction of the movable part 214. As a result, the base 210 and the connecting part 220 form a roughly frame shape in a plan view. The first support part 230 and the second support part 240 are connected to the base 210 in the +A direction and the -A direction. The third support part 250 and the fourth support part 260 are connected to the base 210 near the connecting part 220.

[0055] The joint part 212 is provided between the base part 210 and the movable part 214. The joint part 212 connects the base part 210 and the movable part 214. The thickness of the joint part 212 along the C axis is thinner than the thickness of the base part 210 along the C axis and the thickness of the movable part 214 along the C axis. The joint part 212 is formed in a constricted shape on both sides along the C axis in a plan view from the +A direction. The joint part 212 functions as a fulcrum when the movable part 214 is displaced relative to the base part 210.

[0056] The movable part 214 is connected to the base part 210 via the joint part 212. The movable part 214 is flat. The movable part 214 has a first main surface 214a and a second main surface 214b. The first main surface 214a is the surface of the movable part 214 facing the +C direction. The second main surface 214b is the surface of the movable part 214 facing the -C direction. The first main surface 214a and the second main surface 214b are opposite sides of each other. The movable part 214 is displaced along the C axis with the joint part 212 as a fulcrum in response to acceleration along the C axis. The joint part 212 and the movable part 214 function as a cantilever.

[0057] The first support part 230 has an arm shape that bends at a right angle along the A axis and the B axis. The first support part 230 is disposed in a position in the +A direction and in the -B direction of the sensor element 200. The second support part 240 has an arm shape that bends at a right angle along the A axis and the B axis. The second support part 240 is disposed in a position in the -A direction and in the -B direction of the sensor element 200. The first support part 230 and the second support part 240 are disposed symmetrically with respect to the center line of the vibration element 270 that is along the B axis in a plan view from the +C direction.

[0058] The third support portion 250 has an arm shape that bends at a right angle along the A axis and the B axis. The third support portion 250 is disposed in a position in the +A direction and in the +B direction of the sensor element 200. The fourth support portion 260 has an arm shape that bends at a right angle along the A axis and the B axis. The fourth support portion 260 is disposed in a position in the -A direction and in the +B direction of the sensor element 200. The third support portion 250 and the fourth support portion 260 are disposed symmetrically with respect to the center line of the vibration element 270 that is along the B axis in a plan view from the +C direction.

[0059] The distal ends of the first support portion 230, the second support portion 240, the third support portion 250, and the fourth support portion 260 are connected to the stepped portion 120c of the package 110. The first support portion 230, the second support portion 240, the third support portion 250, and the fourth support portion 260 support the base portion 210 within the accommodation space 111.

[0060] Both ends of the vibration element 270 along the B axis are connected to the base portion 210 and the movable portion 214 of the substrate structure 201. The vibration element 270 is provided on the base portion 210 and the movable portion 214, straddling the joint portion 212.

[0061] As an example, the vibration element 270 is formed of a quartz substrate. The vibration element 270 may be formed of a piezoelectric material other than quartz. The vibration element 270 and the substrate structure 201 are preferably formed of the same material. By forming the vibration element 270 and the substrate structure 201 of the same material, the difference between the linear expansion coefficient of the substrate structure 201 and the linear expansion coefficient of the vibration element 270 becomes small. It becomes possible to suppress the stress applied from the substrate structure 201 to the vibration element 270 due to the difference in linear expansion coefficient.

[0062] As an example, the vibration element 270 is a double-ended tuning fork type vibration element. The vibration element 270 has a first vibrating beam 271a, a second vibrating beam 271b, a first element base 272a, and a second element base 272b. The first vibrating beam 271a and the second vibrating beam 271b each extend along the B axis. The first element base 272a is connected to the +B direction ends of the first vibrating beam 271a and the second vibrating beam 271b. The first element base 272a is connected to the movable part 214. The second element base 272b is connected to the -B direction ends of the first vibrating beam 271a and the second vibrating beam 271b. The second element base 272b is connected to the base 210 of the substrate structure 201. The vibration element 270 is not limited to a double-ended tuning fork type vibration element. The vibration element 270 may be a single beam type vibration element having one vibration beam portion.

[0063] The vibration element 270 has an excitation electrode (not shown) provided on its surface. When an AC voltage drive signal is applied to the excitation electrode provided on the vibration element 270, the first vibrating beam 271a and the second vibrating beam 271b perform flexural vibration along the A axis, moving away from or approaching each other. The vibration element 270 functions as a resonator.

[0064] The sensor element 200 has a plurality of mass portions 280. Of the plurality of mass portions 280, a first mass portion 280a is provided on the first main surface 214a of the movable portion 214. Two first mass portions 280a are provided on the first main surface 214a. The first mass portion 280a is bonded to the first main surface 214a via a bonding material (not shown). Of the plurality of mass portions 280, a second mass portion 280b is provided on the second main surface 214b of the movable portion 214. Two second mass portions 280b are provided on the second main surface 214b. The second mass portion 280b is bonded to the second main surface 214b via a bonding material (not shown). The mass portion 280 is made of a metal such as copper or gold. The number of mass portions 280 may be one.

[0065] When acceleration in the +C direction is applied to the sensor element 200, the movable part 214 is displaced in the -C direction with the joint part 212 as a fulcrum. When the movable part 214 is displaced in the -C direction, a force is applied to the first element base 272a and the second element base 272b in directions that move them away from each other along the B axis. Tensile stress is generated in the first vibrating beam part 271a and the second vibrating beam part 271b. The tensile stress increases the resonance frequencies of the first vibrating beam part 271a and the second vibrating beam part 271b.

[0066] When acceleration in the -C direction is applied to the sensor element 200, the movable part 214 is displaced in the +C direction with the joint part 212 as the fulcrum. When the movable part 214 is displaced in the +C direction, a force is applied to the first element base part 272a and the second element base part 272b in a direction that moves them toward each other along the B axis. Compressive stress is generated in the first vibrating beam part 271a and the second vibrating beam part 271b. The compressive stress lowers the resonance frequencies of the first vibrating beam part 271a and the second vibrating beam part 271b.

[0067] The sensor element 200 can detect acceleration in the +C direction and the −C direction based on the resonance frequency of the vibration element 270. The sensor element 200 is a frequency change type acceleration sensor element whose detection axis is the C axis.

[0068] When a drive signal is applied to the electrodes of the sensor element 200 provided in the inertial sensor 100 via the external terminal 145, the internal terminal 140, the fixed portion connection terminal 225, etc., the first vibrating beam portion 271a and the second vibrating beam portion 271b resonate at a predetermined frequency. The inertial sensor 100 outputs the resonant frequency of the sensor element 200, which changes depending on the acceleration, as an output signal.

[0069] The inertial sensor 100 is a frequency change type acceleration sensor whose detection axis is the C-axis. The inertial sensor 100 can detect acceleration in a desired direction by being positioned so that the C-axis, which is the detection axis, is aligned with the desired direction.

[0070] 8 and 9 show a schematic configuration of a first circuit board 31a, which is an example of the circuit board 31. FIG. 8 shows a plan view of the first circuit board 31a from the -Z direction. FIG. 8 shows the first surface S1 side of the first circuit board 31a. FIG. 8 virtually shows the first fixing member 51 and the second fixing member 53. FIG. 9 shows a plan view of the first circuit board 31a from the +Z direction. FIG. 9 shows the second surface S2 side of the first circuit board 31a. FIG. 9 shows the first fixing member 51 and the second fixing member 53.

[0071] The first fixing member 51 fixes the first circuit board 31a to the first seat 11e of the container 11 at a middle position along the X axis of the first circuit board 31a and at a position near the end of the first circuit board 31a in the -Y direction.

[0072] The second fixing member 53 fixes the first circuit board 31a to the second seat 11f of the container 11 at a position in the +Y direction of the first fixing member 51 near the end of the first circuit board 31a in the +Y direction.

[0073] A first inertial sensor 101, a second inertial sensor 102, a third inertial sensor 103, a fifth inertial sensor 105, and a sixth inertial sensor 106 are arranged on a first surface S1 of the first circuit board 31a. The first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 are arranged on the first circuit board 31a in the -X direction along the X axis in the order of the first inertial sensor 101, the third inertial sensor 103, and the second inertial sensor 102. The X axis corresponds to an example of the first axis. The -X direction corresponds to an example of the first direction. A fourth inertial sensor 104, a connector 33, and a processing circuit 35 are arranged on a second surface S2 of the first circuit board 31a.

[0074] The C-axis of the sensor element 200 provided in the first inertial sensor 101 coincides or nearly coincides with the Z-axis. The Z-axis is an axis perpendicular to the first circuit board 31a. The Z-axis corresponds to an example of a vertical axis. The vibration element 270 of the first inertial sensor 101 is disposed so that the B-axis corresponds to the X-axis, and vibrates along the Y-axis. The first inertial sensor 101 corresponds to an example of a first sensor. The first detection value, which is the Z-axis acceleration detection value, corresponds to an example of a physical quantity along the vertical axis.

[0075] The C-axis of the sensor element 200 provided in the second inertial sensor 102 coincides or nearly coincides with the Y-axis. The Y-axis corresponds to an example of the second axis. The vibration element 270 of the second inertial sensor 102 is disposed so that the B-axis corresponds to the Z-axis, and vibrates along the X-axis. The second inertial sensor 102 corresponds to an example of a second sensor. The second detection value, which is the Y-axis acceleration detection value, corresponds to an example of a physical quantity along the second axis.

[0076] The C-axis of the sensor element 200 included in the third inertial sensor 103 coincides with or substantially coincides with the X-axis. The vibration element 270 of the third inertial sensor 103 is disposed so that the B-axis corresponds to the Z-axis, and vibrates along the Y-axis. The third inertial sensor 103 corresponds to an example of a third sensor. The third detection value, which is the X-axis acceleration detection value, corresponds to an example of a physical quantity along the first axis.

[0077] The C-axis of the sensor element 200 included in the fourth inertial sensor 104 coincides with or substantially coincides with the Z-axis. The vibration element 270 of the fourth inertial sensor 104 is disposed so that the B-axis corresponds to the X-axis, and vibrates along the Y-axis. The fourth inertial sensor 104 corresponds to an example of a fourth sensor. The fourth detection value, which is the Z-axis acceleration detection value, corresponds to an example of a physical quantity along the vertical axis.

[0078] The first inertial sensor 101 and the fourth inertial sensor 104 are arranged opposite each other along the Z axis to form a differential pair, enabling the generation of a Z-axis differential signal. The Z-axis differential signal is the difference between a first detection value detected by the first inertial sensor 101 and a fourth detection value detected by the fourth inertial sensor 104. The generation of the Z-axis differential signal makes it possible to cancel out noise caused by stress from the first circuit board 31a. This improves the accuracy of the measurement value of acceleration along the Z axis output from the inertial measurement device 1.

[0079] The C-axis of the sensor element 200 included in the fifth inertial sensor 105 coincides with or substantially coincides with the Y-axis. The vibration element 270 of the fifth inertial sensor 105 is disposed so that the B-axis corresponds to the Z-axis, and vibrates along the X-axis. The fifth inertial sensor 105 corresponds to an example of a fifth sensor. The fifth detection value, which is the Y-axis acceleration detection value, corresponds to an example of a physical quantity along the second axis.

[0080] The second inertial sensor 102 and the fifth inertial sensor 105 are arranged opposite each other along the Y-axis, forming a differential pair and enabling the generation of a Y-axis differential signal. The Y-axis differential signal is the difference between the second detection value detected by the second inertial sensor 102 and the fifth detection value detected by the fifth inertial sensor 105. The generation of the Y-axis differential signal makes it possible to cancel out noise caused by stress from the first circuit board 31a. This improves the accuracy of the measurement value of acceleration along the Y-axis output from the inertial measurement device 1.

[0081] The C-axis of the sensor element 200 included in the sixth inertial sensor 106 coincides with or substantially coincides with the X-axis. The vibration element 270 of the sixth inertial sensor 106 is disposed so that the B-axis corresponds to the Z-axis, and vibrates along the Y-axis. The sixth inertial sensor 106 corresponds to an example of a sixth sensor. The sixth detection value, which is the X-axis acceleration detection value, corresponds to an example of a physical quantity along the first axis.

[0082] The third inertial sensor 103 and the sixth inertial sensor 106 are arranged opposite each other along the X-axis, forming a differential pair and enabling the generation of an X-axis differential signal. The X-axis differential signal is the difference between a third detection value detected by the third inertial sensor 103 and a sixth detection value detected by the sixth inertial sensor 106. The generation of the X-axis differential signal makes it possible to cancel out noise caused by stress from the first circuit board 31a. This improves the accuracy of the measurement value of acceleration along the X-axis output from the inertial measurement device 1.

[0083] The inertial sensor 100 has a natural frequency in the vibration element 270. If multiple inertial sensors 100 are simply placed on the circuit board 31, interference may occur due to the natural frequencies of the multiple inertial sensors 100. In other words, if the frequency difference between the natural frequencies of the multiple inertial sensors 100 falls within the measurement band, errors in the measurement signal increase. For example, if the measurement band is 0 Hz to 460 Hz and the frequency difference between the natural frequencies of two inertial sensors 100 is 350 Hz, errors in the measurement signal due to the natural frequencies will increase. If the effects of vibration interference cannot be ignored, the manufacturer of the inertial measurement unit 1 must perform pairing before mounting the inertial sensors 100 on the circuit board 31 to select a combination of multiple inertial sensors 100 such that the frequency difference between the natural frequencies does not fall within the measurement band.

[0084] Pairing is affected by the vibration direction of the vibration elements 270 included in the inertial sensor 100. When the vibration directions of the vibration elements 270 of two inertial sensors 100 are along the same axis, more precision is required for pairing the two inertial sensors 100. In the case of multiple inertial sensors 100 shown in FIG. 8 , the vibration element 270 in the first inertial sensor 101 vibrates along the Y axis, and the vibration element 270 in the second inertial sensor 102 vibrates along the X axis. Furthermore, because the first inertial sensor 101 and the second inertial sensor 102 are separated by a virtual area VA between the first fixing member 51 and the second fixing member 53, vibration interference is reduced to a negligible level, making pairing unnecessary.

[0085] The first circuit board 31a shown in FIG. 8 has the first inertial sensor 101, the third inertial sensor 103, and the second inertial sensor 102 mounted in this order in the -X direction along the X axis.

[0086] The fourth inertial sensor 104 is disposed at a second surface opposing position facing the first inertial sensor 101 across the first circuit board 31a. The fifth inertial sensor 105 is disposed at a Y-axis opposing position in the -Y direction along the Y axis relative to the second inertial sensor 102. The sixth inertial sensor 106 is disposed at an X-axis opposing position in the -X direction along the X axis relative to the third inertial sensor 103.

[0087] The first fixing member 51 is disposed between the first inertial sensor 101 and the second inertial sensor 102 in the direction along the X-axis. The first inertial sensor 101, the first fixing member 51, and the second inertial sensor 102 are disposed in the −X direction along the X-axis in the order of the first inertial sensor 101, the first fixing member 51, and the second inertial sensor 102.

[0088] The second fixing member 53 is disposed in the +Y direction perpendicular to the X-axis relative to the first fixing member 51. The second fixing member 53 is disposed between the first inertial sensor 101 and the second inertial sensor 102 in the direction along the X-axis. The second fixing member 53 may be disposed in a direction intersecting the X-axis from the first fixing member 51, as long as the second fixing member 53 is disposed between the first inertial sensor 101 and the second inertial sensor 102 in the direction along the X-axis. The intersecting direction includes a direction inclined with respect to the Y-axis.

[0089] The first inertial sensor 101 and the second inertial sensor 102 are disposed at positions sandwiching an imaginary area VA between the first fixing member 51 and the second fixing member 53 when viewed along the Z axis. That is, when viewed along the Z axis, the second inertial sensor 102 is separated from the first inertial sensor 101 by the imaginary area VA. By disposing the first fixing member 51 and the second fixing member 53 between the first inertial sensor 101 and the second inertial sensor 102, interference between the natural frequencies of the first inertial sensor 101 and the second inertial sensor 102, whose vibration elements 270 vibrate in different directions, is further suppressed. This makes it easier to pair the first inertial sensor 101 and the second inertial sensor 102. Alternatively, pairing the first inertial sensor 101 and the second inertial sensor 102 may be unnecessary.

[0090] When the six inertial sensors 100 are mounted on the first circuit board 31a, pairing is performed for each combination of the inertial sensors 100. By eliminating the need to pair the first inertial sensor 101 and the second inertial sensor 102, the effort required to mount the inertial sensors 100 on the first circuit board 31a is reduced. Furthermore, the number of inertial sensors 100 that become unusable due to pairing is reduced, improving manufacturing yield.

[0091] The third inertial sensor 103 is disposed on a virtual area VA between the first fixing member 51 and the second fixing member 53. The virtual area VA is a band-shaped virtual area connecting the first fixing member 51 and the second fixing member 53 along the Y axis. By disposing the third inertial sensor 103 on the virtual area VA, the influence of the natural frequencies of the first inertial sensor 101 and the second inertial sensor 102 and the influence of the natural frequencies of the other inertial sensors 100 on the third inertial sensor 103 are further reduced.

[0092] As described above, by disposing the first fixing member 51 and the second fixing member 53 between the first inertial sensor 101 and the second inertial sensor 102 when viewed along the Z axis, interference between the natural frequencies of the first inertial sensor 101 and the second inertial sensor 102, whose vibration elements 270 vibrate in different directions, is further suppressed. This makes it easier to pair the first inertial sensor 101 and the second inertial sensor 102. Alternatively, pairing the first inertial sensor 101 and the second inertial sensor 102 may be unnecessary.

[0093] The inertial measurement unit 1 is provided with a third inertial sensor 103 that detects an X-axis acceleration detection value along the X-axis, thereby making it possible to measure acceleration in three axes.

[0094] The third inertial sensor 103 is disposed between the first inertial sensor 101 and the second inertial sensor 102 on the virtual area VA connecting the first fixed member 51 and the second fixed member 53, thereby increasing the rigidity and weight on the virtual area VA. This further reduces the influence of the natural frequencies of the first inertial sensor 101 and the second inertial sensor 102 and the influence of the natural frequencies of the other inertial sensors 100 on the third inertial sensor 103.

[0095] The inertial measurement device 1 includes a fourth inertial sensor 104 that faces the first inertial sensor 101 via the first circuit board 31a, a fifth inertial sensor 105 that faces the second inertial sensor 102 along the Y axis, and a sixth inertial sensor 106 that faces the third inertial sensor 103 along the X axis. By configuring a differential pair for each axis in this way, the accuracy of the acceleration measurement values ​​along each axis is improved.

[0096] Fig. 10 shows a schematic configuration of second circuit board 31b, which is an example of circuit board 31. Fig. 10 shows a plan view of second circuit board 31b from the -Z direction. Fig. 10 shows first surface S1 of second circuit board 31b. Fig. 10 virtually shows first fixing member 51 and second fixing member 53.

[0097] The second circuit board 31b has two inertial sensors 100 mounted thereon. The two inertial sensors 100 are a first inertial sensor 101 and a second inertial sensor 102. The first inertial sensor 101 and the second inertial sensor 102 are disposed along the X-axis at positions sandwiching the first fixing member 51 and the second fixing member 53.

[0098] The first fixing member 51 fixes the second circuit board 31b to the first seat 11e of the container 11 at a middle position along the X axis of the second circuit board 31b and at a position near the end of the second circuit board 31b in the -Y direction.

[0099] The second fixing member 53 fixes the second circuit board 31b to the second seat 11f of the container 11 at a position in the +Y direction of the first fixing member 51 near the end of the second circuit board 31b in the +Y direction.

[0100] The first inertial sensor 101 and the second inertial sensor 102 are disposed at positions sandwiching the area between the first fixing member 51 and the second fixing member 53 when viewed in the direction along the Z axis. By disposing the first fixing member 51 and the second fixing member 53 between the first inertial sensor 101 and the second inertial sensor 102, interference between the natural frequencies of the first inertial sensor 101 and the second inertial sensor 102, whose vibration elements 270 vibrate in different directions, is suppressed.

[0101] Fig. 11 shows a schematic configuration of a third circuit board 31c, which is an example of the circuit board 31. Fig. 11 shows a plan view of the third circuit board 31c from the -Z direction. Fig. 11 shows the first surface S1 of the third circuit board 31c. Fig. 11 virtually shows the first fixing member 51, the second fixing member 53, the third fixing member 57, and the fourth fixing member 59.

[0102] The third circuit board 31c has three inertial sensors 100 mounted thereon. The three inertial sensors 100 are a first inertial sensor 101, a second inertial sensor 102, and a third inertial sensor 103. The first inertial sensor 101 and the second inertial sensor 102 are arranged along the X axis at positions sandwiching the first fixing member 51 and the second fixing member 53. The first inertial sensor 101 and the third inertial sensor 103 are arranged along the X axis at positions sandwiching the third fixing member 57 and the fourth fixing member 59. The first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 are arranged in the -X direction along the X axis in the order of the third inertial sensor 103, the first inertial sensor 101, and the second inertial sensor 102.

[0103] The first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 provided on the third circuit board 31c have the same configuration as the first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 provided on the first circuit board 31a.

[0104] The first fixing member 51 fixes the third circuit board 31c to the container 11 at a middle position along the X axis of the third circuit board 31c and at a position near the end of the third circuit board 31c in the -Y direction. When the inertial measurement unit 1 includes the third circuit board 31c, a base is provided on the container 11 at a position where the first fixing member 51 is to be disposed. The base is not shown. The first fixing member 51 fixes the third circuit board 31c to the base of the container 11.

[0105] The first fixing member 51 is disposed between the first inertial sensor 101 and the second inertial sensor 102 along the X axis. The first inertial sensor 101, the first fixing member 51, and the second inertial sensor 102 are disposed in the −X direction along the X axis in the order of the first inertial sensor 101, the first fixing member 51, and the second inertial sensor 102.

[0106] The second fixing member 53 fixes the third circuit board 31c to the container 11 at a position near the end of the third circuit board 31c in the +Y direction of the first fixing member 51. When the inertial measurement unit 1 includes the third circuit board 31c, a base is provided on the container 11 at a position where the second fixing member 53 is to be disposed. The base is not shown. The second fixing member 53 fixes the third circuit board 31c to the base of the container 11.

[0107] The second fixing member 53 is disposed in the +Y direction perpendicular to the X-axis relative to the first fixing member 51. The second fixing member 53 is disposed along the X-axis between the first inertial sensor 101 and the second inertial sensor 102. The second fixing member 53 may be disposed in a direction intersecting the X-axis from the first fixing member 51, as long as the second fixing member 53 is disposed between the first inertial sensor 101 and the second inertial sensor 102 along the X-axis.

[0108] The third fixing member 57 fixes the third circuit board 31c to the first seat 11e of the container 11 at a middle position along the X axis of the third circuit board 31c and at a position near the end of the third circuit board 31c in the -Y direction.

[0109] The third fixing member 57 is disposed between the first inertial sensor 101 and the third inertial sensor 103 along the X-axis. The first inertial sensor 101, the third fixing member 57, and the third inertial sensor 103 are disposed in the −X direction along the X-axis in the order of the third inertial sensor 103, the third fixing member 57, and the first inertial sensor 101.

[0110] The fourth fixing member 59 fixes the third circuit board 31c to the second seat 11f of the container 11 at a position in the +Y direction of the third fixing member 57 and near the end of the third circuit board 31c in the +Y direction.

[0111] The fourth fixing member 59 is disposed in the +Y direction perpendicular to the X-axis with respect to the third fixing member 57. The fourth fixing member 59 is disposed along the X-axis between the first inertial sensor 101 and the third inertial sensor 103. The fourth fixing member 59 may be disposed in a direction intersecting the X-axis from the third fixing member 57, as long as the fourth fixing member 59 is disposed between the first inertial sensor 101 and the third inertial sensor 103 along the X-axis. If the direction from the first fixing member 51 to the second fixing member 53 is parallel to the direction from the third fixing member 57 to the fourth fixing member 59, the size of the third circuit board 31c can be reduced.

[0112] The first inertial sensor 101 and the second inertial sensor 102 are disposed at positions sandwiching the area between the first fixing member 51 and the second fixing member 53 when viewed in the direction along the Z axis. By disposing the first fixing member 51 and the second fixing member 53 between the first inertial sensor 101 and the second inertial sensor 102, interference between the natural frequencies of the first inertial sensor 101 and the second inertial sensor 102, whose vibration elements 270 vibrate in different directions, is suppressed. This makes pairing the first inertial sensor 101 and the second inertial sensor 102 easy or unnecessary.

[0113] The first inertial sensor 101 and the third inertial sensor 103 are disposed at positions sandwiching an area between the third fixing member 57 and the fourth fixing member 59 when viewed in the direction along the Z axis. By disposing the third fixing member 57 and the fourth fixing member 59 between the first inertial sensor 101 and the third inertial sensor 103, interference between the natural frequencies of the first inertial sensor 101 and the third inertial sensor 103 is suppressed. This makes pairing the first inertial sensor 101 and the third inertial sensor 103 easy or unnecessary.

[0114] The first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 are disposed at positions sandwiching an area between a pair of fixing members. The first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 each suppress interference with the natural frequencies of the other inertial sensors 100. This makes pairing the first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 easy or unnecessary.

[0115] The third circuit board 31c shown in FIG. 11 includes three inertial sensors 100, but is not limited to this. The third circuit board 31c may include a fourth inertial sensor 104, a fifth inertial sensor 105, and a sixth inertial sensor 106. In this case, the fourth inertial sensor 104 is disposed opposite the first inertial sensor 101 via the third circuit board 31c. The fourth inertial sensor 104 is disposed on the second surface S2 of the third circuit board 31c. The fourth inertial sensor 104 is disposed between the first fixing member 51 and the third fixing member 57 along the X axis. The fifth inertial sensor 105 faces the second inertial sensor 102 along the Y axis. The fifth inertial sensor 105 is disposed in a position closer to the -X direction than the first fixing member 51 and the second fixing member 53. The sixth inertial sensor 106 faces the third inertial sensor 103 along the X axis. The sixth inertial sensor 106 is disposed at a position further in the +X direction than the third fixed member 57 and the fourth fixed member 59.

[0116] Fig. 12 shows a schematic configuration of a fourth circuit board 31d, which is an example of the circuit board 31. Fig. 12 shows a plan view of the fourth circuit board 31d from the -Z direction. Fig. 12 shows a first surface S1 of the fourth circuit board 31d. Fig. 12 virtually shows a first fixing member 51, a second fixing member 53, a third fixing member 57, and a fourth fixing member 59.

[0117] The fourth circuit board 31d has three inertial sensors 100 mounted thereon. The three inertial sensors 100 are a first inertial sensor 101, a second inertial sensor 102, and a third inertial sensor 103. The first inertial sensor 101 and the second inertial sensor 102 are arranged along the X axis at positions sandwiching the first fixing member 51 and the second fixing member 53. The second inertial sensor 102 and the third inertial sensor 103 are arranged along the X axis at positions sandwiching the third fixing member 57 and the fourth fixing member 59. The first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 are arranged in this order in the -X direction along the X axis.

[0118] The first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 provided on the fourth circuit board 31d have the same configuration as the first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 provided on the first circuit board 31a.

[0119] The first fixing member 51 fixes the fourth circuit board 31d to the first seat 11e of the container 11 at a middle position along the X axis of the fourth circuit board 31d and at a position near the end of the fourth circuit board 31d in the -Y direction.

[0120] The first fixing member 51 is disposed between the first inertial sensor 101 and the second inertial sensor 102 along the X axis. The first inertial sensor 101, the first fixing member 51, and the second inertial sensor 102 are disposed in the −X direction along the X axis in the order of the first inertial sensor 101, the first fixing member 51, and the second inertial sensor 102.

[0121] The second fixing member 53 fixes the fourth circuit board 31d to the second seat 11f of the container 11 at a position in the +Y direction of the first fixing member 51 and near the end of the fourth circuit board 31d in the +Y direction.

[0122] The second fixing member 53 is disposed in the +Y direction perpendicular to the X-axis relative to the first fixing member 51. The second fixing member 53 is disposed along the X-axis between the first inertial sensor 101 and the second inertial sensor 102. The second fixing member 53 may be disposed in a direction intersecting the X-axis from the first fixing member 51, as long as the second fixing member 53 is disposed between the first inertial sensor 101 and the second inertial sensor 102 along the X-axis.

[0123] The third fixing member 57 fixes the fourth circuit board 31d to the container 11 at a middle position along the X axis of the fourth circuit board 31d and at a position near the end of the fourth circuit board 31d in the -Y direction. When the inertial measurement unit 1 includes the fourth circuit board 31d, a base is provided on the container 11 at a position where the third fixing member 57 is to be disposed. The base is not shown. The third fixing member 57 fixes the fourth circuit board 31d to the base of the container 11.

[0124] The third fixing member 57 is disposed along the X-axis between the second inertial sensor 102 and the third inertial sensor 103. The second inertial sensor 102, the third fixing member 57, and the third inertial sensor 103 are disposed in the −X direction along the X-axis in the order of the second inertial sensor 102, the third fixing member 57, and the third inertial sensor 103.

[0125] The fourth fixing member 59 fixes the fourth circuit board 31d to the container 11 at a position near the end of the fourth circuit board 31d in the +Y direction, relative to the third fixing member 57. When the inertial measurement unit 1 includes the fourth circuit board 31d, a base is provided on the container 11 at a position where the fourth fixing member 59 is to be disposed. The base is not shown. The fourth fixing member 59 fixes the fourth circuit board 31d to the base of the container 11.

[0126] The fourth fixing member 59 is disposed in the +Y direction perpendicular to the X-axis with respect to the third fixing member 57. The fourth fixing member 59 is disposed along the X-axis between the second inertial sensor 102 and the third inertial sensor 103. The fourth fixing member 59 may be disposed in a direction intersecting the X-axis from the third fixing member 57, as long as the fourth fixing member 59 is disposed between the second inertial sensor 102 and the third inertial sensor 103 along the X-axis. If the direction from the first fixing member 51 to the second fixing member 53 is parallel to the direction from the third fixing member 57 to the fourth fixing member 59, the size of the fourth circuit board 31d can be reduced.

[0127] The first inertial sensor 101 and the second inertial sensor 102 are disposed at positions sandwiching the area between the first fixing member 51 and the second fixing member 53 when viewed in the direction along the Z axis. By disposing the first fixing member 51 and the second fixing member 53 between the first inertial sensor 101 and the second inertial sensor 102, interference between the natural frequencies of the first inertial sensor 101 and the second inertial sensor 102, whose vibration elements 270 vibrate in different directions, is suppressed. This makes pairing the first inertial sensor 101 and the second inertial sensor 102 easy or unnecessary.

[0128] The second inertial sensor 102 and the third inertial sensor 103 are disposed at positions sandwiching an area between the third fixing member 57 and the fourth fixing member 59 when viewed in the direction along the Z axis. By disposing the third fixing member 57 and the fourth fixing member 59 between the second inertial sensor 102 and the third inertial sensor 103, interference between the natural frequencies of the second inertial sensor 102 and the third inertial sensor 103 is suppressed. This makes pairing the second inertial sensor 102 and the third inertial sensor 103 easy or unnecessary.

[0129] The first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 are disposed at positions sandwiching an area between a pair of fixing members. The first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 each suppress interference with the natural frequencies of the other inertial sensors 100. This makes pairing the first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 easy or unnecessary.

[0130] The fourth circuit board 31d shown in FIG. 12 includes three inertial sensors 100, but is not limited to this. The fourth circuit board 31d may include a fourth inertial sensor 104, a fifth inertial sensor 105, and a sixth inertial sensor 106. In this case, the fourth inertial sensor 104 is disposed opposite the first inertial sensor 101 via the fourth circuit board 31d. The fourth inertial sensor 104 is disposed on the second surface S2 of the fourth circuit board 31d. The fourth inertial sensor 104 is disposed in a position in the +X direction relative to the first fixing member 51 and the second fixing member 53 along the X axis. The fifth inertial sensor 105 faces the second inertial sensor 102 along the Y axis. The fifth inertial sensor 105 is disposed between the first fixing member 51 and the third fixing member 57 along the X axis. The sixth inertial sensor 106 faces the third inertial sensor 103 along the X axis. The sixth inertial sensor 106 is disposed at a position further in the −X direction than the third fixing member 57 and the fourth fixing member 59.

[0131] Fig. 13 shows a schematic configuration of a fifth circuit board 31e, which is an example of the circuit board 31. Fig. 13 shows a plan view of the fifth circuit board 31e from the -Z direction. Fig. 13 shows a first surface S1 of the fifth circuit board 31e. Fig. 13 virtually shows a first fixing member 51, a second fixing member 53, a third fixing member 57, and a fourth fixing member 59.

[0132] The fifth circuit board 31e has three inertial sensors 100 mounted thereon. The three inertial sensors 100 are a first inertial sensor 101, a second inertial sensor 102, and a third inertial sensor 103. The first inertial sensor 101 and the third inertial sensor 103 are arranged along the X axis at positions sandwiching the first fixing member 51 and the second fixing member 53. The second inertial sensor 102 and the third inertial sensor 103 are arranged along the X axis at positions sandwiching the third fixing member 57 and the fourth fixing member 59. The first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 are arranged in the order of the first inertial sensor 101, the third inertial sensor 103, and the second inertial sensor 102 in the -X direction along the X axis.

[0133] The first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 provided on the fifth circuit board 31e have the same configuration as the first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 provided on the first circuit board 31a.

[0134] The first fixing member 51 fixes the fifth circuit board 31e to the first seat 11e of the container 11 at a middle position along the X axis of the fifth circuit board 31e and at a position near the end of the fifth circuit board 31e in the -Y direction.

[0135] The first fixing member 51 is disposed between the first inertial sensor 101 and the third inertial sensor 103 along the X axis. The first inertial sensor 101, the first fixing member 51, and the third inertial sensor 103 are disposed in the −X direction along the X axis in the order of the first inertial sensor 101, the first fixing member 51, and the third inertial sensor 103.

[0136] The second fixing member 53 fixes the fifth circuit board 31e to the second seat 11f of the container 11 at a position in the +Y direction of the first fixing member 51 and near the end of the fifth circuit board 31e in the +Y direction.

[0137] The second fixing member 53 is disposed in the +Y direction perpendicular to the X-axis with respect to the first fixing member 51. The second fixing member 53 is disposed along the X-axis between the first inertial sensor 101 and the third inertial sensor 103. The second fixing member 53 may be disposed in a direction intersecting the X-axis from the first fixing member 51, as long as the second fixing member 53 is disposed between the first inertial sensor 101 and the third inertial sensor 103 along the X-axis.

[0138] The third fixing member 57 fixes the fifth circuit board 31e to the container 11 at a middle position along the X axis of the fifth circuit board 31e and at a position near the end of the fifth circuit board 31e in the -Y direction. When the inertial measurement unit 1 includes the fifth circuit board 31e, a base is provided on the container 11 at a position where the third fixing member 57 is to be disposed. The base is not shown. The third fixing member 57 fixes the fifth circuit board 31e to the base of the container 11.

[0139] The third fixing member 57 is disposed along the X-axis between the second inertial sensor 102 and the third inertial sensor 103. The second inertial sensor 102, the third fixing member 57, and the third inertial sensor 103 are disposed in the −X direction along the X-axis in the order of the third inertial sensor 103, the third fixing member 57, and the second inertial sensor 102.

[0140] The fourth fixing member 59 fixes the fifth circuit board 31e to the container 11 at a position near the end of the fifth circuit board 31e in the +Y direction, in the +Y direction of the third fixing member 57. When the inertial measurement unit 1 includes the fifth circuit board 31e, a base is provided on the container 11 at a position where the fourth fixing member 59 is to be disposed. The base is not shown. The fourth fixing member 59 fixes the fifth circuit board 31e to the base of the container 11.

[0141] The fourth fixing member 59 is disposed in the +Y direction perpendicular to the X-axis with respect to the third fixing member 57. The fourth fixing member 59 is disposed along the X-axis between the second inertial sensor 102 and the third inertial sensor 103. The fourth fixing member 59 may be disposed in a direction intersecting the X-axis from the third fixing member 57, as long as the fourth fixing member 59 is disposed between the second inertial sensor 102 and the third inertial sensor 103 along the X-axis. If the direction from the first fixing member 51 to the second fixing member 53 is parallel to the direction from the third fixing member 57 to the fourth fixing member 59, the size of the fifth circuit board 31e can be reduced.

[0142] The first inertial sensor 101 and the third inertial sensor 103 are disposed at positions sandwiching the area between the first fixing member 51 and the second fixing member 53 when viewed in the direction along the Z axis. By disposing the first fixing member 51 and the second fixing member 53 between the first inertial sensor 101 and the third inertial sensor 103, interference between the natural frequencies of the first inertial sensor 101 and the third inertial sensor 103 is suppressed. This makes pairing the first inertial sensor 101 and the third inertial sensor 103 easy or unnecessary.

[0143] The second inertial sensor 102 and the third inertial sensor 103 are disposed at positions sandwiching an area between the third fixing member 57 and the fourth fixing member 59 when viewed in the direction along the Z axis. By disposing the third fixing member 57 and the fourth fixing member 59 between the second inertial sensor 102 and the third inertial sensor 103, interference between the natural frequencies of the second inertial sensor 102 and the third inertial sensor 103 is suppressed. This makes pairing the second inertial sensor 102 and the third inertial sensor 103 easy or unnecessary.

[0144] The first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 are disposed at positions sandwiching an area between a pair of fixing members. The first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 each suppress interference with the natural frequencies of the other inertial sensors 100. This makes pairing the first inertial sensor 101, the second inertial sensor 102, and the third inertial sensor 103 easy or unnecessary.

[0145] The fifth circuit board 31e shown in FIG. 13 includes three inertial sensors 100, but is not limited to this. The fifth circuit board 31e may include a fourth inertial sensor 104, a fifth inertial sensor 105, and a sixth inertial sensor 106. In this case, the fourth inertial sensor 104 is disposed opposite the first inertial sensor 101 via the fifth circuit board 31e. The fourth inertial sensor 104 is disposed on the second surface S2 of the fifth circuit board 31e. The fourth inertial sensor 104 is disposed in a position on the +X direction from the first fixing member 51 and the second fixing member 53 along the X axis. The fifth inertial sensor 105 faces the second inertial sensor 102 along the Y axis. The fifth inertial sensor 105 is disposed in a position on the −X direction from the third fixing member 57 and the fourth fixing member 59. The sixth inertial sensor 106 faces the third inertial sensor 103 along the X axis. The sixth inertial sensor 106 is disposed at a position between the first fixed member 51 and the third fixed member 57 . [Explanation of symbols]

[0146] 1...inertial measurement unit, 11...container, 11a...bottom, 11b...side, 11c...inner surface, 11d...support surface, 11e...first base, 11f...second base, 11g...third base, 11h...projection, 13...screw hole, 15...opening, 17...fixing projection, 19...screw hole for fixing lid, 21...lid, 23...through hole, 31...circuit board, 31a...first circuit board, 31b...second circuit board, 31c...third circuit board, 31d...fourth circuit board, 31e...fifth circuit board, 33...connector 100...inertial sensor, 101...first inertial sensor, 102...second inertial sensor, 103...third inertial sensor, 104...fourth inertial sensor, 105...fifth inertial sensor, 106...sixth inertial sensor, 110...package, 111...accommodation space, 120...package base, 12 0a...inner surface, 120b...inner bottom surface, 120c...step portion, 120d...outer bottom surface, 130...lid, 132...lid joining member, 140...internal terminal, 141...conductive adhesive, 145...external terminal, 200...sensor element, 201...substrate structure, 210...base, 212...joint portion, 214...movable portion, 214a...first main surface, 214b...second main surface, 220...connecting portion, 225...fixed portion connecting terminal, 230...first support portion, 240...second support portion, 250...third support portion, 260...fourth support portion, 270...vibration element, 271a...first vibrating beam portion, 271b...second vibrating beam portion, 272a...first element base portion, 272b...second element base portion, 280...mass portion, 280a...first mass portion, 280b...second mass portion, D...depth, D1...first detection direction, D2...second detection direction, D3...third detection direction, D4...fourth detection direction, D5...fifth detection direction, D6...sixth detection direction, H...height, S1...first surface, S2...second surface, VA...virtual area, W...width.

Claims

1. A substrate; a container for accommodating the substrate; a first fixing member and a second fixing member that fix the substrate to the container, respectively; a first sensor disposed on the substrate and detecting a physical quantity along a normal axis relative to the substrate; a second sensor disposed on the substrate; the first sensor, the first fixing member, the second fixing member, and the second sensor are arranged in this order in a first direction along a first axis parallel to the substrate; the second sensor detects a physical quantity along a second axis parallel to the substrate and perpendicular to the first axis; the second sensor is separated from the first sensor by a region between the first fixing member and the second fixing member when viewed in a direction along the vertical axis; Inertial measurement unit.

2. a third sensor disposed on the substrate and configured to detect a physical quantity along the first axis; 10. The inertial measurement unit of claim 1.

3. a third fixing member and a fourth fixing member, each fixing the substrate to the container; the third sensor, the third fixing member, the fourth fixing member, and the first sensor are arranged in this order in the first direction; the third sensor is separated from the first sensor by a region between the third fixing member and the fourth fixing member when viewed in a direction along the vertical axis; 3. The inertial measurement unit of claim 2.

4. a third fixing member and a fourth fixing member, each fixing the substrate to the container; the second sensor, the third fixing member, the fourth fixing member, and the third sensor are arranged in this order in the first direction; the third sensor is separated from the second sensor by a region between the third fixing member and the fourth fixing member when viewed in a direction along the vertical axis; 3. The inertial measurement unit of claim 2.

5. a direction from the third fixing member toward the fourth fixing member is parallel to a direction from the first fixing member toward the second fixing member; 5. The inertial measurement device according to claim 3 or 4.

6. the third sensor is disposed in a region between the first fixing member and the second fixing member when viewed in a direction along the vertical axis.

3. The inertial measurement unit of claim 2.

7. a fourth sensor disposed on the substrate opposite the first sensor with the substrate interposed therebetween, the fourth sensor detecting a physical quantity along the vertical axis; a fifth sensor disposed on the substrate opposite the second sensor and configured to detect a physical quantity along the second axis; a sixth sensor disposed on the substrate opposite the third sensor and configured to detect a physical quantity along the first axis; 3. The inertial measurement unit of claim 2.

Images