Sensor module
Patent Information
- Application Number
- JP2023141176
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-08-31
- Publication Date
- 2025-03-13
Smart Images
Figure 2025034663000001_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to a sensor module. [Background technology]
[0002] The inertial measurement device described in Patent Document 1 has an inner case, a sensor board mounted on the bottom surface of the inner case, and an outer case that covers the inner case and houses the sensor board between the inner case and the outer case. The sensor board has a substrate, a Z-axis angular velocity sensor and an acceleration sensor mounted on the top surface of the substrate, and an X-axis angular velocity sensor and a Y-axis angular velocity sensor mounted on the side surface of the substrate.
[0003] A recess is formed on the bottom surface of the inner case, and the X-axis, Y-axis, and Z-axis angular velocity sensors and acceleration sensors are disposed at positions overlapping with the recess. The recess is filled with a filling material, which seals the entire Z-axis angular velocity sensor and acceleration sensor, and seals the upper halves of the X-axis and Y-axis angular velocity sensors.
[0004] In the inertial measurement device of Patent Document 1, the filler member is disposed to reduce the influence of external noise vibrations and improve the stability of detection accuracy. [Prior art documents] [Patent documents]
[0005] [Patent Document 1] JP 2017-020829 A Summary of the Invention [Problem to be solved by the invention]
[0006] However, in the inertial measurement device of Patent Document 1, the X-axis angular velocity sensor and the Y-axis angular velocity sensor are mounted on the side surface of the board, which means that the mounting reliability of the X-axis angular velocity sensor and the Y-axis angular velocity sensor is low, and there is a risk that the detection characteristics will change over time. [Means for solving the problem]
[0007] The sensor module of the present invention includes a substrate having a first surface and a second surface that are in a reverse relationship, and a side surface including a first side surface; a first relay board having a first front surface and a first back surface in a reverse relationship, the first back surface being mounted on the first side surface with the first back surface facing the first side surface; a first inertial sensor including a first package mounted on the first surface of the first relay board and a first sensor element accommodated in the first package; A thickness direction of the substrate is defined as a first direction, The linear expansion coefficient of the substrate in the first direction is α1, The linear expansion coefficient of the first intermediate substrate in the first direction is defined as α2, When the linear expansion coefficient of the first package in the first direction is α3, The relationship α1>α2>α3 is satisfied. [Brief description of the drawings]
[0008] [Figure 1] FIG. 2 is a top view showing the sensor module according to the first embodiment. [Diagram 2] FIG. 2 is an exploded perspective view of the sensor module. [Diagram 3] 2 is a cross-sectional view taken along line AA in FIG. 1. [Figure 4] FIG. 2 is a cross-sectional view taken along line BB in FIG. [Diagram 5] FIG. 4 is a cross-sectional view of a first relay board. [Figure 6] FIG. 4 is a cross-sectional view of a second relay board. [Figure 7] FIG. 2 is a cross-sectional view of the angular velocity sensor. [Figure 8]FIG. 2 is a plan view of the angular velocity sensor. [Figure 9] 5A and 5B are schematic diagrams illustrating a driving state of the angular velocity sensor. [Figure 10] 5A and 5B are schematic diagrams illustrating a driving state of the angular velocity sensor. [Figure 11] FIG. 11 is a cross-sectional view of a first relay board according to a second embodiment. [Figure 12] FIG. 11 is a cross-sectional view of a second relay substrate according to a second embodiment. [Figure 13] FIG. 11 is a top view showing a sensor module according to a third embodiment. [Figure 14] 14 is a cross-sectional view taken along line CC in FIG. 13. [Figure 15] 14 is a cross-sectional view taken along line DD in FIG. 13. [Figure 16] FIG. 13 is a cross-sectional view of a first relay board according to a fourth embodiment. [Figure 17] FIG. 13 is a cross-sectional view of a second relay substrate according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0009] The sensor module of the present invention will be described in detail below based on the embodiment shown in the attached drawings. For convenience of explanation, three mutually orthogonal axes are illustrated as the X-axis, Y-axis, and Z-axis in Figs. 1 to 6 and Figs. 11 to 17. For convenience of explanation, the direction parallel to the X-axis is also referred to as the "X-axis direction", the direction parallel to the Y-axis is also referred to as the "Y-axis direction", and the direction parallel to the Z-axis is also referred to as the "Z-axis direction". The arrow side of the Z-axis direction is also referred to as the "upper" and the opposite side as the "lower".
[0010] First Embodiment FIG. 1 is a top view showing a sensor module according to a first embodiment. FIG. 2 is an exploded perspective view of the sensor module. FIG. 3 is a cross-sectional view taken along line AA in FIG. 1. FIG. 4 is a cross-sectional view taken along line BB in FIG. 1. FIG. 5 is a cross-sectional view of a first relay board. FIG. 6 is a cross-sectional view of a second relay board. FIG. 7 is a cross-sectional view of an angular velocity sensor. FIG. 8 is a plan view of the angular velocity sensor. FIGS. 9 and 10 are schematic views showing the driving states of the angular velocity sensor, respectively.
[0011] 1 is an inertial measurement sensor unit (IMU) that detects the posture and behavior of an object to which the sensor is attached, such as an automobile or a robot. The object to which the sensor is attached is not limited to a moving body such as an automobile or a robot, but may be, for example, a structure such as a bridge, an elevated road, or a track. When the sensor module 1 is attached to a structure, the sensor module 1 is used as a structural health monitoring system that checks the soundness of the structure.
[0012] As shown in FIGS. 1 and 2, the sensor module 1 has a case 2 and a sensor substrate 50 accommodated in the case 2.
[0013] <Case 2> As shown in Fig. 1 and Fig. 2, the case 2 has an inner case 3 and an outer case 4 arranged to cover the inner case 3. The inner case 3 and the outer case 4 are each made of aluminum. This provides the case 2 with sufficiently high rigidity. In particular, in this embodiment, the surfaces of the inner case 3 and the outer case 4 are each anodized to provide insulation to the case 2. However, the materials constituting the inner case 3 and the outer case 4 are not particularly limited, and may be made of metal materials such as titanium, magnesium, and stainless steel, or ceramics such as alumina and titania.
[0014] The inner case 3 is a box-like shape that opens upward and has a rectangular parallelepiped shape with two diagonal corners chamfered flatly. Furthermore, screw holes 31 for fixing the outer case 4 are formed in the other two diagonal corners of the inner case 3.
[0015] The inner case 3 also has a recess 32 that opens to the top surface 3a. The inner case 3 also has a mounting base 33 that protrudes from the bottom surface of the recess 32 and on which the sensor board 50 is placed. The inner case 3 also has a through hole 34 that penetrates the bottom surface and the top surface of the mounting base 33. The through hole 34 is a hole for exposing a connector 51, which will be described later, to the outside of the case 2.
[0016] The outer case 4 is box-shaped and rectangular parallelepiped-shaped with an opening on the bottom side. The outer case 4 covers the inner case 3 from above by inserting the inner case 3 into a recess 43 that opens on the bottom side. The shape of the opening of the outer case 4 is aligned with the outer shape of the inner case 3. This prevents the outer case 4 from rattling relative to the inner case 3.
[0017] Moreover, screw holes 41 overlapping with the screw holes 31 are formed in two corners located on one diagonal of the outer case 4. Then, the inner case 3 and the outer case 4 are fixed by mounting screws B1 inserted into the screw holes 31 and 41. However, the method of fixing the outer case 4 to the inner case 3 is not particularly limited. Moreover, screw holes 42 are formed in two corners located on the other diagonal of the outer case 4. Then, the sensor module 1 is attached to the attachment body by mounting screws B2 inserted into these two screw holes 42. However, the method of attaching to the attachment body is not particularly limited.
[0018] <Sensor board 50> As shown in FIG. 1, FIG. 3, and FIG. 4, the sensor board 50 has a board 5. The board 5 has an upper surface 5a as a first surface and a lower surface 5b as a second surface, which are in a front-back relationship, and a side surface. Such a board 5 is placed on the mounting base 33 of the inner case 3 with the lower surface 5b facing downward, and is screwed in place with screws (not shown). However, the method of fixing the board 5 to the inner case 3 is not particularly limited. In addition, the side surfaces of the board 5 include a first side surface 5c facing the negative side in the X-axis direction, a third side surface 5e facing the first side surface 5c and facing the positive side in the X-axis direction, a second side surface 5d facing the positive side in the Y-axis direction, and a fourth side surface 5f facing the second side surface 5d and facing the negative side in the Y-axis direction. Such a board 5 is a circuit board on which wiring EL is formed, and is composed of, for example, a multi-layer glass epoxy board. However, the configuration of the board 5 is not particularly limited.
[0019] The sensor substrate 50 also has a connector 51 mounted on the lower surface 5b of the substrate 5. The sensor substrate 50 and an external device are electrically connected via this connector 51.
[0020] As shown in FIG. 5, the sensor substrate 50 has a first relay substrate 61 mounted on the first side surface 5c of the substrate 5. The first relay substrate 61 has a front surface 61a as a first front surface and a back surface 61b as a first back surface, which are in a front-back relationship. The first relay substrate 61 is joined to the first side surface 5c of the substrate 5 at the back surface 61b with the normals of the front surface 61a and the back surface 61b aligned along the X-axis, that is, perpendicular to the substrate 5. The first relay substrate 61 is a circuit substrate on which the wiring EL1 is formed, and is made of, for example, a multi-layer glass epoxy substrate. In this embodiment, the wiring EL1 formed on the front surface 61a and the wiring EL1 formed on the back surface are electrically connected via a through electrode formed to penetrate the first relay substrate 61.
[0021] Moreover, the first relay board 61 is disposed so as to protrude above and below the first side surface 5c in a plan view of the first side surface 5c. With this configuration, the first relay board 61 can be bonded to the substrate 5 from both the upper surface 5a side and the lower surface 5b side. This increases the bonding strength between the first relay board 61 and the substrate 5.
[0022] Such a first relay board 61 is mechanically joined and electrically connected to the substrate 5 by solder H1 serving as a first conductive portion. This facilitates electrical connection between the first relay board 61 and the substrate 5. However, the first conductive portion is not particularly limited and may be, for example, a conductive adhesive, a metal bump, or the like.
[0023] The solder H1 includes a plurality of fillet-shaped upper solders H11 formed across the upper surface 5a of the substrate 5 and the rear surface 61b of the first relay substrate 61, and a plurality of fillet-shaped lower solders H12 formed across the lower surface 5b of the substrate 5 and the rear surface 61b of the first relay substrate 61. By joining the first relay substrate 61 to the substrate 5 from both the upper surface 5a side and the lower surface 5b side in this manner, the joining strength between the first relay substrate 61 and the substrate 5 can be increased. However, the method of joining the first relay substrate 61 to the substrate 5 is not particularly limited, and for example, either the upper solders H11 or the lower solders H12 may be omitted.
[0024] The sensor board 50 also has an X-axis angular velocity sensor 7X as a first inertial sensor mounted on the front surface 61a of the first intermediate board 61. The X-axis angular velocity sensor 7X is a sensor for detecting an angular velocity ωx about the X-axis.
[0025] As shown in FIG. 6, the sensor substrate 50 has a second relay substrate 62 mounted on the second side surface 5d of the substrate 5. The second relay substrate 62 is a circuit substrate on which the wiring EL2 is formed, and is made of, for example, a multi-layer glass epoxy substrate. However, the configuration of the second relay substrate 62 is not particularly limited. The second relay substrate 62 has a front surface 62a as a second front surface and a back surface 62b as a second back surface, which are in a front-back relationship with each other. The second relay substrate 62 is joined to the second side surface 5d of the substrate 5 at the back surface 62b in a position where the normals of the front surface 62a and the back surface 62b are along the Y axis, that is, in a position perpendicular to the substrate 5 and the first relay substrate 61.
[0026] Moreover, the second relay board 62 is disposed so as to protrude above and below the second side surface 5d in a plan view of the second side surface 5d. With this configuration, the second relay board 62 can be bonded to the substrate 5 from both the upper surface 5a side and the lower surface 5b side. This increases the bonding strength between the second relay board 62 and the substrate 5.
[0027] Such a second relay board 62 is mechanically joined and electrically connected to the board 5 by solder H2 serving as a second conductive portion. This facilitates electrical connection between the second relay board 62 and the board 5. However, the second conductive portion is not particularly limited and may be, for example, a conductive adhesive, a metal bump, or the like.
[0028] The solder H2 includes a plurality of fillet-shaped upper solders H21 formed across the upper surface 5a of the substrate 5 and the rear surface 62b of the second relay substrate 62, and a plurality of fillet-shaped lower solders H22 formed across the lower surface 5b of the substrate 5 and the rear surface 62b of the second relay substrate 62. By joining the second relay substrate 62 to the substrate 5 from both the upper surface 5a side and the lower surface 5b side in this manner, the joining strength between the second relay substrate 62 and the substrate 5 can be increased. However, the method of joining the second relay substrate 62 to the substrate 5 is not particularly limited, and for example, either the upper solders H21 or the lower solders H22 may be omitted.
[0029] The sensor board 50 also has a Y-axis angular velocity sensor 7Y as a second inertial sensor mounted on the front surface 62a of the second relay board 62. The Y-axis angular velocity sensor 7Y is a sensor for detecting an angular velocity ωy about the Y-axis.
[0030] 3, the sensor substrate 50 has a Z-axis angular velocity sensor 7Z mounted on the lower surface 5b of the substrate 5 as a third inertial sensor. The Z-axis angular velocity sensor 7Z is a sensor for detecting an angular velocity ωz about the Z-axis. In this way, by providing the X-axis, Y-axis, and Z-axis angular velocity sensors 7X, 7Y, and 7Z, that is, three inertial sensors, the sensor module 1 can measure more inertia, thereby improving its usability.
[0031] The X-axis angular velocity sensor 7X, the Y-axis angular velocity sensor 7Y, and the Z-axis angular velocity sensor 7Z are each packaged surface-mount components. This allows them to exhibit higher mechanical strength than components with exposed elements. Furthermore, it makes it easier to mount the X-axis angular velocity sensor 7X, the Y-axis angular velocity sensor 7Y, and the Z-axis angular velocity sensor 7Z on the substrate 5.
[0032] In addition, the X-axis angular velocity sensor 7X, the Y-axis angular velocity sensor 7Y, and the Z-axis angular velocity sensor 7Z have the same basic configuration except that the vibration frequencies of the sensor elements 74, which will be described later, are different in order to suppress interference between them, and they are arranged at right angles to each other so that their detection axes face the X-axis, Y-axis, and Z-axis.
[0033] 7 and 8, each of the X-axis angular velocity sensor 7X, the Y-axis angular velocity sensor 7Y, and the Z-axis angular velocity sensor 7Z has a package 71 and a sensor element 74 housed in the package 71. The package 71 also has a recess 721 opening on a front surface 72a, a box-shaped base 72 supporting the sensor element 74 housed in the recess 721, and a lid 73 joined to the base 72 so as to close the opening of the recess 721. A connection terminal (not shown) electrically connected to the sensor element 74 is formed on a back surface 72b of the base 72.
[0034] In this embodiment, the package 71 of the X-axis angular velocity sensor 7X is a first package, and the sensor element 74 of the X-axis angular velocity sensor 7X is a first sensor element. The package 71 of the Y-axis angular velocity sensor 7Y is a second package, and the sensor element 74 of the Y-axis angular velocity sensor 7Y is a second sensor element.
[0035] The X-axis angular velocity sensor 7X is joined to the surface 61a of the first relay board 61 on the back surface 72b of the base 72, and is electrically connected to the first relay board 61 via the connection terminal. The Y-axis angular velocity sensor 7Y is joined to the surface 62a of the second relay board 62 on the back surface 72b of the base 72, and is electrically connected to the second relay board 62 via the connection terminal. The Z-axis angular velocity sensor 7Z is joined to the lower surface 5b of the board 5 on the back surface 72b of the base 72, and is electrically connected to the board 5 via the connection terminal.
[0036] The sensor element 74 is, for example, a quartz crystal vibration element having a drive vibration arm and a detection vibration arm. In the configuration of FIG. 8, the quartz crystal vibration element has a base 740 fixed to a base 72 via a support substrate 75, four drive vibration arms 742, and two detection vibration arms 741. In such a quartz crystal vibration element, when an angular velocity ω about a detection axis J is applied in a state in which a drive signal is applied to drive and vibrate the drive vibration arm 742 as shown in FIG. 9, a detection vibration is excited in the detection vibration arm 741 by the Coriolis force as shown in FIG. 10. Then, the charge generated in the detection vibration arm 741 by the detection vibration is extracted as a detection signal, and the angular velocity ω can be obtained based on the extracted detection signal.
[0037] The configurations of the X-axis angular velocity sensor 7X, the Y-axis angular velocity sensor 7Y, and the Z-axis angular velocity sensor 7Z have been described above. The X-axis angular velocity sensor 7X is disposed so that the detection axis J is along the X-axis, the Y-axis angular velocity sensor 7Y is disposed so that the detection axis J is along the Y-axis, and the Z-axis angular velocity sensor 7Z is disposed so that the detection axis J is along the Z-axis. However, the configurations of the X-axis angular velocity sensor 7X, the Y-axis angular velocity sensor 7Y, and the Z-axis angular velocity sensor 7Z are not particularly limited. For example, they may be configured to use silicon MEMS vibration elements as sensor elements.
[0038] 1, the sensor substrate 50 has a circuit element 8 as an electronic component mounted on the upper surface 5a of the substrate 5. The circuit element 8 is electrically connected to the X-axis angular velocity sensor 7X, the Y-axis angular velocity sensor 7Y, the Z-axis angular velocity sensor 7Z, and a connector 51 via the substrate 5. The circuit element 8 is, for example, an MCU (Micro Controller Unit), and controls each part of the sensor module 1. Specifically, the circuit element 8 has a control circuit that controls the driving of the X-axis, Y-axis, and Z-axis angular velocity sensors 7X, 7Y, and 7Z, and an interface circuit that communicates with the outside.
[0039] The control circuit independently controls the driving of the X-axis, Y-axis, and Z-axis angular velocity sensors 7X, 7Y, and 7Z, and independently detects the angular velocity around each of the X-axis, Y-axis, and Z-axis based on the detection signals output from the X-axis, Y-axis, and Z-axis angular velocity sensors 7X, 7Y, and 7Z. The interface circuit transmits and receives signals, receives commands from an external device via the connector 51, and outputs detected angular velocities to the external device. The communication method of the interface circuit is not particularly limited, but in this embodiment, it is SPI (Serial Peripheral Interface) communication. SPI communication is a communication method suitable for connecting multiple sensors. Since all signals related to angular velocity can be output from one pin, it is possible to reduce the number of pins in the sensor module 1.
[0040] In reality, in addition to the X-axis angular velocity sensor 7X, Y-axis angular velocity sensor 7Y, Z-axis angular velocity sensor 7Z and circuit element 8 described above, a number of electronic components are mounted on the substrate 5; however, for the sake of convenience, these will not be shown or described.
[0041] Here, when the linear expansion coefficient in the thickness direction of the substrate 5, i.e., the Z-axis direction which is the first direction, is α1, the linear expansion coefficient in the planar direction of the first relay substrate 61, i.e., the Z-axis direction along the thickness direction of the substrate 5, is α2, and the linear expansion coefficient in the planar direction of the package 71 of the X-axis angular velocity sensor 7X, specifically, the base 72, i.e., the Z-axis direction along the thickness direction of the substrate 5, is α3, the sensor module 1 satisfies the relationship α1>α2>α3. In this embodiment, α1 is about 40 ppm / °C, α2 is 12 ppm / °C, and α3 is about 7 ppm / °C. However, as long as the relationship α1>α2>α3 is satisfied, the values of these α1, α2, and α3 are not particularly limited.
[0042] By satisfying the relationship of α1>α2>α3, the mounting reliability of the X-axis angular velocity sensor 7X is improved. Specifically, when the X-axis angular velocity sensor 7X is mounted directly on the first side surface 5c of the substrate 5 as in the conventional case, the difference between the linear expansion coefficients α1 and α3 is large, so that a large thermal stress is generated at the joint between them, and the solder H1 may peel off or crack. In contrast, as in the present embodiment, by interposing the first relay board 61 having the linear expansion coefficient α2 located between the linear expansion coefficients α1 and α3 between the substrate 5 and the X-axis angular velocity sensor 7X, the thermal stress can be distributed to the joint between the substrate 5 and the first relay board 61 and the joint between the first relay board 61 and the X-axis angular velocity sensor 7X. Therefore, the thermal stress applied to one joint is reduced, and the peeling or cracking of the solder H1 is effectively suppressed, improving the mounting reliability.
[0043] Although not shown, various circuit elements for the X-axis angular velocity sensor 7X, such as a capacitor, a regulator, a power supply circuit, etc., can also be mounted on the first relay board 61. This allows the circuit elements for the X-axis angular velocity sensor 7X to be easily mounted in the vicinity of the X-axis angular velocity sensor 7X, improving the circuit characteristics.
[0044] As with the first relay board 61 described above, when the linear expansion coefficient in the Z-axis direction along the planar direction of the second relay board 62, i.e., the thickness direction of the board 5, is α4, and the linear expansion coefficient in the Z-axis direction along the planar direction of the package 71 of the Y-axis angular velocity sensor 7Y, specifically, the base 72, i.e., the thickness direction of the board 5, is α5, the sensor module 1 satisfies the relationship α1>α4>α5. In this embodiment, α4=α2, and α5=α3. However, the values of α4 and α5 are not particularly limited.
[0045] By satisfying the relationship α1>α4>α5, the mounting reliability of the Y-axis angular velocity sensor 7Y is improved. Specifically, when the Y-axis angular velocity sensor 7Y is mounted directly on the second side surface 5d of the substrate 5 as in the conventional case, the difference between the linear expansion coefficients α1 and α5 is large, so that a large thermal stress is generated at the joint between them, and the solder H2 may peel off or crack. In contrast, as in the present embodiment, by interposing the second relay substrate 62 having the linear expansion coefficient α4 located between the linear expansion coefficients α1 and α5 between the substrate 5 and the Y-axis angular velocity sensor 7Y, the thermal stress can be distributed to the joint between the substrate 5 and the second relay substrate 62 and the joint between the second relay substrate 62 and the Y-axis angular velocity sensor 7Y. Therefore, the thermal stress applied to one joint is reduced, and the peeling or cracking of the solder H2 is effectively suppressed, improving the mounting reliability.
[0046] Although not shown, various circuit elements for the Y-axis angular velocity sensor 7Y, such as a capacitor, a regulator, a power supply circuit, etc., can also be mounted on the second relay board 62. This allows the circuit elements for the Y-axis angular velocity sensor 7Y to be easily mounted in the vicinity of the Y-axis angular velocity sensor 7Y, improving the circuit characteristics.
[0047] The sensor module 1 of this embodiment has been described above. As described above, the sensor module 1 includes the substrate 5 having the upper surface 5a as a first surface and the lower surface 5b as a second surface, which are in a front-back relationship, and a side surface including the first side surface 5c, the first relay substrate 61 having the front surface 61a as a first front surface and the back surface 61b as a first back surface, which are in a front-back relationship, and mounted on the first side surface 5c with the back surface 61b facing the first side surface 5c, the package 71 as a first package mounted on the front surface 61a of the first relay substrate 61, and the X-axis angular velocity sensor 7X as a first inertial sensor including the sensor element 74 housed in the package 71. When the thickness direction of the substrate 2 is the first direction, i.e., the Z-axis direction, the linear expansion coefficient of the substrate 5 in the Z-axis direction is α1, the linear expansion coefficient of the first relay substrate 61 in the Z-axis direction is α2, and the linear expansion coefficient of the package 71 of the X-axis angular velocity sensor 7X in the Z-axis direction is α3, the relationship α1>α2>α3 is satisfied. In this way, by interposing the first relay substrate 61 having the linear expansion coefficient α2 located between the linear expansion coefficients α1 and α3 between the substrate 5 and the X-axis angular velocity sensor 7X, the thermal stress caused by the difference in linear expansion coefficients can be distributed to the joint portion between the substrate 5 and the first relay substrate 61 and the joint portion between the first relay substrate 61 and the X-axis angular velocity sensor 7X. Therefore, stress is less likely to concentrate, and mounting reliability is improved.
[0048] As described above, the side surface of the substrate 5 further includes a second side surface 5d different from the first side surface 5c. The sensor module 1 includes a second relay substrate 62 having a front surface 62a as a second front surface and a back surface 62b as a second back surface, and mounted on the second side surface 5d with the back surface 62b facing the second side surface 5d, a package 71 as a second package mounted on the front surface 62a of the second relay substrate 62, and a sensor element 74 as a second sensor element housed in the package 71. When the linear expansion coefficient in the Z-axis direction of the second relay substrate 62 is α4 and the linear expansion coefficient in the Z-axis direction of the package 71 of the Y-axis angular velocity sensor 7Y is α5, the relationship α1>α4>α5 is satisfied. In this way, by interposing the second relay board 62 having the linear expansion coefficient α4 located between the linear expansion coefficients α1 and α5 between the substrate 5 and the Y-axis angular velocity sensor 7Y, the thermal stress caused by the difference in linear expansion coefficients can be dispersed to the joint between the substrate 5 and the second relay board 62 and the joint between the second relay board 62 and the Y-axis angular velocity sensor 7Y. This makes it difficult for stress to concentrate, improving mounting reliability.
[0049] As described above, the sensor module 1 also has the Z-axis angular velocity sensor 7Z as a third inertial sensor mounted on the upper surface 5a or the lower surface 5b of the substrate 5. This allows the sensor module 1 to measure more inertia.
[0050] As described above, the first relay board 61 protrudes from the first side surface 5c toward the upper surface 5a and the lower surface 5b in a plan view of the first side surface 5c, and the second relay board 62 protrudes from the second side surface 5d toward the upper surface 5a and the lower surface 5b in a plan view of the second side surface 5d. This allows the first relay board 61 to be bonded to the board 5 from both the upper surface 5a and the lower surface 5b. This allows the bonding strength between the first relay board 61 and the board 5 to be increased. Similarly, the second relay board 62 can be bonded to the board 5 from both the upper surface 5a and the lower surface 5b. This allows the bonding strength between the second relay board 62 and the board 5 to be increased.
[0051] As described above, the first relay board 61 is electrically connected to the board 5 via solder H1 serving as a first conductive portion, and the second relay board 62 is electrically connected to the board 5 via solder H2 serving as a second conductive portion. This facilitates electrical connection between the first relay board 61 and the board 5. Similarly, it facilitates electrical connection between the second relay board 62 and the board 5.
[0052] <Second embodiment> Fig. 11 is a cross-sectional view of a first relay board according to the second embodiment, and Fig. 12 is a cross-sectional view of a second relay board according to the second embodiment.
[0053] This embodiment is similar to the first embodiment described above, except that the position of the X-axis angular velocity sensor 7X on the first relay board 61 and the position of the Y-axis angular velocity sensor 7Y on the second relay board 62 are different. In the following description, the present embodiment will be described focusing on the differences from the first embodiment described above, and a description of the similarities will be omitted. In each drawing of this embodiment, the same reference numerals are used for the same configurations as those in the above-mentioned embodiment.
[0054] As shown in FIG. 11, in this embodiment, the X-axis angular velocity sensor 7X is disposed apart from the first side surface 5c in a plan view of the first side surface 5c, that is, in a plan view from the X-axis direction. That is, in FIG. 11, compared to FIG. 5, the X-axis angular velocity sensor 7X is disposed shifted toward the negative side in the Z-axis direction so as not to overlap with the first side surface 5c. Since the first relay board 61 is mounted on the first side surface 5c, a large thermal stress is applied to the position overlapping with the first side surface 5c. Therefore, by disposing the X-axis angular velocity sensor 7X so as not to overlap with the first side surface 5c as in this embodiment, the thermal stress is less likely to be transmitted to the X-axis angular velocity sensor 7X. Therefore, the deterioration of the detection characteristics of the X-axis angular velocity sensor 7X can be more effectively suppressed. Note that in this embodiment, the X-axis angular velocity sensor 7X is disposed shifted downward from the first side surface 5c, but this is not limited thereto, and may be disposed shifted upward, for example.
[0055] Similarly, as shown in FIG. 12, in a plan view of the second side surface 5d, that is, in a plan view from the Y-axis direction, the Y-axis angular velocity sensor 7Y is disposed away from the second side surface 5d. That is, in FIG. 12, compared to FIG. 6, the Y-axis angular velocity sensor 7Y is disposed shifted toward the negative side in the Z-axis direction so as not to overlap with the second side surface 5d. Since the second relay board 62 is mounted on the second side surface 5d, a large thermal stress is applied to the position overlapping with the second side surface 5d. Therefore, by disposing the Y-axis angular velocity sensor 7Y so as not to overlap with the second side surface 5d as in this embodiment, the thermal stress is less likely to be transmitted to the Y-axis angular velocity sensor 7Y. Therefore, the deterioration of the detection characteristics of the Y-axis angular velocity sensor 7Y can be more effectively suppressed. Note that in this embodiment, the Y-axis angular velocity sensor 7Y is disposed shifted downward with respect to the second side surface 5d, but this is not limited thereto, and may be disposed shifted upward, for example.
[0056] In the sensor module 1 as described above, the X-axis angular velocity sensor 7X is disposed away from the first side surface 5c in a plan view of the first side surface 5c, and the Y-axis angular velocity sensor 7Y is disposed away from the second side surface 5d in a plan view of the second side surface 5d. This makes it difficult for thermal stress to be transmitted to the X-axis angular velocity sensor 7X and the Y-axis angular velocity sensor 7Y. This makes it possible to more effectively suppress deterioration in the detection characteristics of the X-axis angular velocity sensor 7X and the Y-axis angular velocity sensor 7Y.
[0057] The second embodiment as described above can also achieve the same effects as the first embodiment.
[0058] <Third embodiment> Fig. 13 is a top view showing a sensor module according to a third embodiment, Fig. 14 is a cross-sectional view taken along line CC in Fig. 13, and Fig. 15 is a cross-sectional view taken along line DD in Fig. 13.
[0059] This embodiment is similar to the first embodiment described above, except for the configuration of the sensor substrate 50. In the following description, the present embodiment will be described focusing on the differences from the first embodiment described above, and the description of the similarities will be omitted. In each drawing of this embodiment, the same reference numerals are used for the same configurations as the above-mentioned embodiment.
[0060] As shown in FIG. 13 to FIG. 15, the sensor substrate 50 of this embodiment has a third relay substrate 63 mounted on the third side surface 5e and a fourth relay substrate 64 mounted on the fourth side surface 5f. The third and fourth relay substrates 63 and 64 are circuit substrates, respectively, and have the same configuration as the first and second relay substrates 61 and 62. The third and fourth relay substrates 63 and 64 are mounted on the substrate 5 in the same manner as the first and second relay substrates 61 and 62. By mounting the third and fourth relay substrates 63 and 64 in this manner, for example, the space in which circuit elements can be mounted is increased compared to the first embodiment described above, and therefore the degree of freedom in design is increased. Also, for example, the substrate 5 can be made smaller by mounting all or part of the circuit elements mounted on the substrate 5 in the first embodiment on the third and fourth relay substrates 63 and 64.
[0061] The third relay board 63 has a front surface 63a as a third front surface and a back surface 63b as a third back surface, which are in a front-back relationship with each other. The third relay board 63 is joined to the third side surface 5e of the board 5 at the back surface 63b with the normal lines of the front surface 63a and the back surface 63b along the X-axis, that is, parallel to the first relay board 61. The third relay board 63 is disposed so as to protrude above and below the third side surface 5e in a plan view of the third side surface 5e. The third relay board 63 is mechanically joined to the board 5 by solder H3 as a third conductive part, and is electrically connected to the board 5. The solder H3 includes a plurality of fillet-shaped upper solders H31 formed across the upper surface 5a of the board 5 and the back surface 63b of the third relay board 63, and a plurality of fillet-shaped lower solders H32 formed across the lower surface 5b of the board 5 and the back surface 63b of the third relay board 63.
[0062] The sensor board 50 also has an X-axis angular velocity sensor 7X as a third inertial sensor mounted on the surface 63a of the third relay board 63. That is, the sensor board 50 of this embodiment has a pair of X-axis angular velocity sensors 7X. According to this configuration, by detecting the angular velocity ωx based on the detection signals output from each X-axis angular velocity sensor 7X, noise is reduced compared to the first embodiment described above, and the angular velocity ωx can be detected more accurately. The detection signals output from the X-axis angular velocity sensor 7X mounted on the surface 63a of the third relay board 63 may be calculated together with the detection signals output from the X-axis angular velocity sensor 7X mounted on the surface 61a of the first relay board 61. The calculation process may be performed by an MCU (Micro Controller Unit) as the circuit element 8, or the calculation process may be an averaging process.
[0063] The fourth relay board 64 has a front surface 64a as a fourth front surface and a back surface 64b as a fourth back surface, which are in a front-back relationship with each other. The fourth relay board 64 is joined to the fourth side surface 5f of the board 5 at the back surface 64b with the normal lines of the front surface 64a and the back surface 64b aligned along the Y axis, i.e., parallel to the second relay board 62. The fourth relay board 64 is disposed so as to protrude above and below the fourth side surface 5f in a plan view of the fourth side surface 5f. The fourth relay board 64 is mechanically joined to the board 5 by solder H4 as a fourth conductive part, and is electrically connected to the board 5. The solder H4 includes a plurality of fillet-shaped upper solders H41 formed across the upper surface 5a of the board 5 and the back surface 64b of the fourth relay board 64, and a plurality of fillet-shaped lower solders H42 formed across the lower surface 5b of the board 5 and the back surface 64b of the fourth relay board 64.
[0064] The sensor board 50 also has a Y-axis angular velocity sensor 7Y as a fourth inertial sensor mounted on the surface 64a of the fourth relay board 64. That is, the sensor board 50 of this embodiment has a pair of Y-axis angular velocity sensors 7Y. According to this configuration, the angular velocity ωy is detected based on the detection signals output from the Y-axis angular velocity sensors 7Y, so that noise is reduced compared to the first embodiment described above, and the angular velocity ωy can be detected more accurately. The detection signals output from the Y-axis angular velocity sensor 7Y mounted on the surface 64a of the fourth relay board 64 may be calculated together with the detection signals output from the Y-axis angular velocity sensor 7Y mounted on the surface 62a of the second relay board 62. The calculation process may be performed by an MCU (Micro Controller Unit) as the circuit element 8, or the calculation process may be an averaging process.
[0065] The sensor substrate 50 also has a pair of Z-axis angular velocity sensors 7Z mounted on the lower surface 5b of the substrate 5. With this configuration, the angular velocity ωz is detected based on the detection signals output from the Z-axis angular velocity sensors 7Z, so that noise is reduced compared to the first embodiment described above, and the angular velocity ωz can be detected with higher accuracy. The detection signals output from the pair of Z-axis angular velocity sensors 7Z mounted on the lower surface 5b of the substrate 5 may be calculated. The calculation process may be performed by an MCU (Micro Controller Unit) as the circuit element 8, or the calculation process may be an averaging process.
[0066] In the sensor module 1 as described above, the side of the substrate 5 further includes a third side 5e facing the first side 5c and a fourth side 5f facing the second side 5d. The sensor module 1 also includes a third relay board 63 having a front surface 63a as a third surface and a back surface 63b as a third back surface, which are in a front-back relationship, and mounted on the third side surface 5e with the back surface 63b facing the third side surface 5e, an X-axis angular velocity sensor 7X as a third inertial sensor mounted on the front surface 63a of the third relay board 63, a fourth relay board 64 having a front surface 64a as a fourth surface and a back surface 64b as a fourth back surface, which are in a front-back relationship, and mounted on the fourth side surface 5f with the back surface 64b facing the fourth side surface 5f, and a Y-axis angular velocity sensor 7Y as a fourth inertial sensor mounted on the front surface 64a of the fourth relay board 64. According to such a configuration, for example, the space in which a circuit element can be mounted is increased compared to the first embodiment described above, and therefore the degree of freedom in design is increased. Also, for example, by mounting all or part of the circuit elements mounted on the substrate 5 in the first embodiment on the third and fourth relay substrates 63 and 64, the substrate 5 can be made smaller. Furthermore, by detecting the angular velocity ωx based on the detection signals output from each X-axis angular velocity sensor 7X, noise is reduced and the angular velocity ωx can be detected with higher accuracy. Similarly, by detecting the angular velocity ωy based on the detection signals output from each Y-axis angular velocity sensor 7Y, noise is reduced and the angular velocity ωy can be detected with higher accuracy.
[0067] The third embodiment as described above can also achieve the same effects as the first embodiment described above.
[0068] <Fourth embodiment> Fig. 16 is a cross-sectional view of a first relay board according to the fourth embodiment, and Fig. 17 is a cross-sectional view of a second relay board according to the fourth embodiment.
[0069] This embodiment is similar to the first embodiment described above, except for the configuration of the sensor substrate 50. In the following description, the present embodiment will be described focusing on the differences from the first embodiment described above, and the description of the similarities will be omitted. In each drawing of this embodiment, the same reference numerals are used for the same configurations as the above-mentioned embodiment.
[0070] As shown in FIG. 16, in the sensor board 50 of this embodiment, the first relay board 61 and the board 5 are electrically connected by a plurality of first pin headers P1. Specifically, in this embodiment, the wiring EL1 is not formed on the back surface 61b of the first relay board 61. Also, a plurality of first pin headers P1 electrically connected to the wiring EL1 formed on the front surface 61a are arranged penetrating the first relay board 61. Then, the first relay board 61 and the board 5 are electrically connected by joining the portion of the first pin header P1 protruding from the back surface 61b to the solder H1. With this configuration, the wiring EL1 can be omitted from the back surface 61b of the first relay board 61, so that the configuration of the first relay board 61 is simplified.
[0071] Similarly, as shown in FIG. 17, in the sensor board 50 of this embodiment, the second relay board 62 and the board 5 are electrically connected by a plurality of second pin headers P2. Specifically, in this embodiment, the wiring EL2 is not formed on the back surface 62b of the second relay board 62. Also, a plurality of second pin headers P2 electrically connected to the wiring EL2 formed on the front surface 62a are disposed penetrating the second relay board 62. Then, the second relay board 62 and the board 5 are electrically connected by joining the portion of the second pin header P2 protruding from the back surface 62b to the solder H2. According to this configuration, the wiring EL2 can be omitted from the back surface 62b of the second relay board 62, so that the configuration of the second relay board 62 is simplified.
[0072] The sensor module 1 as described above has a first pin header P1 disposed to penetrate the first relay board 61 and electrically connected to the solder H1, and a second pin header P2 disposed to penetrate the second relay board 62 and electrically connected to the solder H2. With this configuration, the wiring EL1 can be omitted from the back surface 61b of the first relay board 61, so the configuration of the first relay board 61 is simplified. Similarly, the wiring EL2 can be omitted from the back surface 62b of the second relay board 62, so the configuration of the second relay board 62 is simplified.
[0073] The fourth embodiment as described above can also achieve the same effects as the first embodiment described above.
[0074] Although the sensor module of the present invention has been described above based on the illustrated embodiment, the present invention is not limited thereto, and the configuration of each part can be replaced with any configuration having a similar function. In addition, any other configuration may be added to the present invention. In addition, each embodiment may be appropriately combined. [Explanation of symbols]
[0075] 1...sensor module, 2...case, 3...inner case, 3a...upper surface, 31...screw hole, 32...recess, 33...mounting stand, 34...through hole, 4...outer case, 41...screw hole, 42...screw hole, 43...recess, 5...substrate, 5a...upper surface, 5b...lower surface, 5c...first side, 5d...second side, 5e...third side, 5f...fourth side, 50...sensor substrate, 51...connector, 61...first relay substrate, 61a...front surface, 61b...reverse surface, 62...second relay substrate, 62a...front surface, 62b...reverse surface, 63...third relay substrate, 63a...front surface, 63b...reverse surface, 64...fourth relay substrate, 64a...front surface, 64b...reverse surface, 7X...X-axis angular velocity sensor, 7Y...Y-axis angular velocity sensor, 7Z...Z-axis angular velocity sensor sensor, 71...package, 72...base, 72a...surface, 72b...backside, 721...recess, 73...lid, 74...sensor element, 740...base, 741...detection vibration arm, 742...drive vibration arm, 75...support substrate, 8...circuit element, B1...mounting screw, B2...mounting screw, EL...wiring, EL1...wiring, EL2...wiring, H1...solder, H11...upper solder, H12...lower solder, H2...solder, H21...upper solder, H22...lower solder, H3...solder, H31...upper solder, H32...lower solder, H4...solder, H41...upper solder, H42...lower solder, J...detection axis, P1...first pin header, P2...second pin header, ω...angular velocity, ωx...angular velocity, ωy...angular velocity, ωz...angular velocity
Claims
1. A substrate having a first surface and a second surface in a reverse relationship and a side surface including a first side surface; a first relay substrate having a first front surface and a first back surface, the first back surface being mounted on the first side surface with the first back surface facing the first side surface; a first inertial sensor including a first package mounted on the first surface of the first relay board and a first sensor element accommodated in the first package; A thickness direction of the substrate is defined as a first direction, The linear expansion coefficient of the substrate in the first direction is α1, The linear expansion coefficient of the first intermediate substrate in the first direction is defined as α2, When the linear expansion coefficient of the first package in the first direction is α3, A sensor module characterized by satisfying the relationship α1>α2>α3.
2. The side surface of the substrate further includes a second side surface different from the first side surface, a second relay substrate having a second front surface and a second back surface in a reverse relationship, the second back surface being mounted on the second side surface with the second back surface facing the second side surface; a second inertial sensor including a second package mounted on the second surface of the second relay board and a second sensor element accommodated in the second package; The linear expansion coefficient of the second intermediate substrate in the first direction is α4, When the linear expansion coefficient of the second package in the first direction is α5, The sensor module according to claim 1 , which satisfies the relationship α1>α4>α5.
3. The sensor module according to claim 1 , further comprising a third inertial sensor mounted on the first surface or the second surface of the substrate.
4. the first relay substrate protrudes from the first side surface toward the first surface side and the second surface side in a plan view of the first side surface, The sensor module according to claim 2 , wherein the second relay substrate protrudes from the second side surface toward the first surface and the second surface in a plan view of the second side surface.
5. the first inertial sensor is disposed at a distance from the first side surface in a plan view of the first side surface, The sensor module according to claim 2 , wherein the second inertial sensor is disposed at a distance from the second side surface in a plan view of the second side surface.
6. the first relay substrate is electrically connected to the substrate via a first conductive portion, The sensor module according to claim 2 , wherein the second relay board is electrically connected to the board via a second conductive portion.
7. a first pin header disposed through the first relay board and electrically connected to the first conductive portion; The sensor module according to claim 6 , further comprising: a second pin header disposed to pass through the second relay board and electrically connected to the second conductive portion.
8. the side surface of the substrate further includes a third side surface facing the first side surface and a fourth side surface facing the second side surface, a third relay substrate having a third front surface and a third back surface which are in a reverse relationship and which is mounted on the third side surface with the third back surface facing the third side surface; a third inertial sensor mounted on the third surface of the third relay substrate; a fourth relay board having a fourth front surface and a fourth back surface which are in a reverse relationship and which is mounted on the fourth side surface with the fourth back surface facing the fourth side surface; The sensor module according to claim 2 , further comprising: a fourth inertial sensor mounted on the fourth surface of the fourth relay board.
Citation Information
Patent Citations
Sensor unit, electronic apparatus, and movable body
JP2017020829A