Physical quantity and composite sensors, inertial measurement units, electronic devices and mobile objects

Abstract

A physical quantity and composite sensor, an inertial measurement unit, an electronic device, and a moving object, having excellent impact resistance and improved reliability. The physical quantity sensor comprises: a movable body including a beam portion, a connecting portion connected to the beam portion and arranged in a direction intersecting the beam portion, and first and second mass portions connected to the connecting portion; first and second fixed electrodes arranged on a supporting substrate, facing the first and second mass portions; and a protrusion arranged in a region where the first and second fixed electrodes are provided, protruding from the supporting substrate toward the first and second mass portions. In the intersecting direction, when the distance from the connection position of the connecting portion with the first and second mass portions to the ends of the first and second mass portions opposite the beam portion is set to L, and the distance from the protrusion to the ends of the first and second mass portions opposite the beam portion is set to L1, the distance L1 is not less than 0.18L and not more than 0.88L.

Description

[0001] This application is a divisional application of a patent application with an application date of August 29, 2018, application number 201810996247.1, and invention name “Physical quantity and composite sensor, inertial measurement unit, electronic device and mobile body”. Technical Field

[0002] The present invention relates to a physical quantity sensor, a composite sensor, an inertial measurement unit, a portable electronic device, an electronic device, and a mobile object. Background Art

[0003] Conventionally, as a method for detecting acceleration as a physical quantity, physical quantity sensors are known that are constructed based on the locking lever principle and detect acceleration based on capacitance that changes as acceleration is applied in the vertical direction. For example, Patent Document 1 discloses an acceleration sensor (physical quantity sensor) comprising a first fixed electrode and a second fixed electrode disposed on a substrate, and movable electrodes arranged symmetrically with respect to the centerline of a torsion beam, with one movable electrode disposed opposite the first fixed electrode and the other opposite the second fixed electrode. Furthermore, the acceleration sensor of Patent Document 1 includes a protrusion that prevents the end of the movable electrode from contacting the substrate.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. WO03 / 044539A1

[0007] In the physical quantity sensor described in Patent Document 1, a connection portion connected to the rotating shaft is provided in a direction intersecting the axial direction of the rotating shaft (torsion beam). Furthermore, the first mass portion (one of the movable electrodes) and the second mass portion (the other of the movable electrodes) are connected via the connection portion. However, in the physical quantity sensor of Patent Document 1, a protrusion that prevents the ends of the movable bodies constituting the first and second mass portions from contacting the support substrate is arranged at a position corresponding to the ends of the first and second mass portions on the opposite side of the rotating shaft. In the case where an excessive acceleration in the vertical direction is applied to the physical quantity sensor and the movable body contacts the support substrate via the protrusion and is subjected to a strong impact, a large stress is generated in the connection portion when the protrusion is arranged at the end, and there is a possibility that damage will occur at the boundary between the first and second mass portions and the connection portion. Summary of the Invention

[0008] The present invention has been made to solve at least a part of the above-mentioned problems, and can be implemented as the following aspects or application examples.

[0009] [Application Example 1] The physical quantity sensor of this application example is characterized in that it comprises: a movable body including a rotating shaft, a connecting portion connected to the rotating shaft and arranged along a cross direction intersecting the rotating shaft, and a mass portion connected to the connecting portion; a detection electrode arranged on a supporting substrate, opposite to the mass portion; and a protrusion arranged in a region where the detection electrode is provided, protruding from the supporting substrate toward the mass portion, and in the cross direction, when the distance from the connection position between the connecting portion and the mass portion to the end of the mass portion on the opposite side of the rotating shaft is set to L, and the distance from the protrusion to the end of the mass portion on the opposite side of the rotating shaft is set to L1, L1 is greater than 0.18L and less than 0.88L.

[0010] According to this application example, the mass portion of the physical quantity sensor is connected to a connecting portion, which is connected to the rotation axis and arranged in a direction intersecting the rotation axis. When acceleration is applied to the physical quantity sensor, the movable body swings about the rotation axis. In addition, the support substrate has a protrusion that protrudes toward the mass portion. In this application example, the protrusion is located within a range of L1 = 0.18L or greater and L1 = 0.88L or less, when the distance from the connection point between the connecting portion and the mass portion to the end of the mass portion opposite the rotation axis is L, and the distance from the protrusion to the end of the mass portion opposite the rotation axis is L1. This structure reduces the bending stress applied to the connecting portion when excessive acceleration is applied to the physical quantity sensor and the movable body contacts the protrusion. For example, when the protrusion is located at L1 = 0.18L, the bending stress applied to the connecting portion is reduced to 0.6 times that when the protrusion is located at the end, thereby suppressing damage at the boundary between the connecting portion and the mass portion. The same applies when the protrusion is at the position of L1 = 0.88 L. Therefore, it is possible to provide a physical quantity sensor having excellent shock resistance and improved reliability.

[0011] [Application Example 2] In the physical quantity sensor described in the above application example, preferably, a plurality of protrusions are provided, and the protrusions are arranged on a straight line parallel to the rotation axis.

[0012] According to this application example, a plurality of protrusions projecting from the support substrate toward the mass unit are provided on a straight line parallel to the rotation axis. This can disperse the impact received by the movable body when the protrusions come into contact with the movable body.

[0013] [Application Example 3] In the physical quantity sensor described in the above application example, it is preferable that the protrusion is provided in line symmetry with respect to a center line bisecting the movable body in the axial direction of the rotation shaft.

[0014] According to this application example, the protrusion is provided line-symmetrically with respect to the center line bisecting the movable body in the axial direction of the rotation shaft. Therefore, the posture of the movable body when the movable body contacts the protrusion can be stabilized.

[0015] [Application Example 4] In the physical quantity sensor described in the above application example, preferably, two mass portions are arranged line-symmetrically with respect to the rotation axis, and the protrusions are provided line-symmetrically with respect to the rotation axis.

[0016] According to this application example, the protrusion is arranged to be linearly symmetrical with respect to the rotation axis. If the protrusion is arranged asymmetrically with respect to the rotation axis, the height of the protrusion needs to be different to make the swing angles of the two mass parts the same. In order to form protrusions of different heights, the process for forming the protrusions increases. However, by arranging the protrusion to be linearly symmetrical with respect to the rotation axis, the swing angles of the two mass parts can be made the same using protrusions of the same height. Therefore, a physical quantity sensor can be efficiently manufactured in which the swing angles of the two mass parts are made the same by the protrusion.

[0017] [Application Example 5] In the physical quantity sensor described in the above application example, preferably, the mass portion has openings penetrating in a lattice pattern, and the protrusions are provided at positions corresponding to centers of four openings arranged in two rows and two columns.

[0018] According to this application example, the mass unit has openings extending through it in a grid pattern. This reduces the air resistance (damping) generated between the movable body and the supporting substrate, thereby improving the sensitivity of the detected physical quantity. Furthermore, the protrusions are positioned corresponding to the centers of the four openings arranged in two rows and two columns. In other words, the protrusions are positioned at locations where the openings are not aligned. Thus, contact between the protrusions and the openings can prevent damage to the mass unit.

[0019] [Application Example 6] In the physical quantity sensor described in the above application example, preferably, the movable body has a slit formed between the connecting portion and the mass portion, and the connecting portion is extended by the slit.

[0020] According to this application example, the movable body has a slit formed between the connecting portion and the mass portion, and the connecting portion is extended by the slit. This further reduces the bending stress applied to the connecting portion, thereby further suppressing damage at the boundary between the connecting portion and the mass portion.

[0021] [Application Example 7] A composite sensor according to this application example is characterized by including: the physical quantity sensor described in the above application example; and an angular velocity sensor.

[0022] According to this application example, a composite sensor can be easily configured, and acceleration data and angular velocity data, for example, can be acquired.

[0023] [Application Example 8] The inertial measurement unit of this application example is characterized by comprising: a physical quantity sensor described in any of the above application examples; an angular velocity sensor; and a control unit that controls the physical quantity sensor and the angular velocity sensor.

[0024] According to this application example, a physical quantity sensor having improved shock resistance can provide an inertial measurement unit with further increased reliability.

[0025] [Application Example 9] The portable electronic device of this application example is characterized in that it comprises: a physical quantity sensor described in any of the above application examples; a shell that accommodates the physical quantity sensor; a processing unit that is accommodated in the shell and processes output data from the physical quantity sensor; a display unit that is accommodated in the shell; and a light-transmitting cover that blocks the opening of the shell.

[0026] According to this application example, a highly reliable portable electronic device with further improved control reliability can be provided using the output data of the physical quantity sensor having improved shock resistance.

[0027] [Application Example 10] An electronic device according to this application example is characterized by including: the physical quantity sensor described in the above application example; and a control unit that performs control based on a detection signal output from the physical quantity sensor.

[0028] According to this application example, it is possible to provide an electronic device including a physical quantity sensor with improved reliability.

[0029] [Application Example 11] A moving object according to this application example is characterized by comprising: the physical quantity sensor described in the above application example; and a control unit that performs control based on a detection signal output from the physical quantity sensor.

[0030] According to this application example, a moving object including a physical quantity sensor with improved reliability can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a plan view schematically showing the physical quantity sensor according to the embodiment.

[0032] Figure 2 yes Figure 1 Cross-sectional view along line AA.

[0033] Figure 3 This is a diagram showing a beam load model for calculating the bending stress applied to the movable body.

[0034] Figure 4 This is a diagram showing the calculation results of the bending stress applied to the movable body.

[0035] Figure 5This is a diagram showing the calculation results of the bending stress applied to the movable body.

[0036] Figure 6 This is a graph showing the relationship between the position of the protrusion and the bending stress.

[0037] Figure 7 This diagram shows the shape of the beam model's displacement when a load is applied.

[0038] Figure 8 This diagram shows the shape of the beam model's displacement when a load is applied.

[0039] Figure 9 It is a cross-sectional view schematically showing the operation of the physical quantity sensor.

[0040] Figure 10 It is a cross-sectional view schematically showing the operation of the physical quantity sensor.

[0041] Figure 11 It is a cross-sectional view schematically showing the operation of the physical quantity sensor.

[0042] Figure 12 It is a cross-sectional view schematically showing the operation of the physical quantity sensor.

[0043] Figure 13 This is a flowchart illustrating a manufacturing process of a physical quantity sensor.

[0044] Figure 14 These are cross-sectional views of the physical quantity sensor during each manufacturing step.

[0045] Figure 15 These are cross-sectional views of the physical quantity sensor during each manufacturing step.

[0046] Figure 16 These are cross-sectional views of the physical quantity sensor during each manufacturing step.

[0047] Figure 17 These are cross-sectional views of the physical quantity sensor during each manufacturing step.

[0048] Figure 18 These are cross-sectional views of the physical quantity sensor during each manufacturing step.

[0049] Figure 19 It is a plan view schematically showing a physical quantity sensor according to a modified example.

[0050] Figure 20 This is a diagram showing the calculation results of the bending stress applied to the movable body.

[0051] Figure 21 This is a functional block diagram showing the schematic structure of a composite sensor.

[0052] Figure 22This is an exploded perspective view showing the schematic structure of an inertial measurement unit.

[0053] Figure 23 This is a perspective view showing an example of arrangement of inertial sensor elements of an inertial measurement unit.

[0054] Figure 24 It is a plan view schematically showing the structure of a portable electronic device.

[0055] Figure 25 This is a functional block diagram showing a schematic configuration of a portable electronic device.

[0056] Figure 26 This is a perspective view showing a schematic configuration of a mobile (or notebook) personal computer as an electronic device including a physical quantity sensor.

[0057] Figure 27 This is a perspective view showing a schematic configuration of a mobile phone (including a PHS) as an electronic device including a physical quantity sensor.

[0058] Figure 28 This is a perspective view schematically showing the configuration of a still digital camera as an electronic device including a physical quantity sensor.

[0059] Figure 29 This is a perspective view schematically showing a car as a moving object equipped with a physical quantity sensor.

[0060] Description of reference numerals:

[0061] 10: Support substrate; 11: First fixed electrode serving as a detection electrode; 12: Second fixed electrode serving as a detection electrode; 13: Virtual electrode; 14: Pillar; 15: Protrusion; 16: Chamber; 17: Main surface; 20: Movable body; 20S: Silicon substrate; 20a: First movable body; 20b: Second movable body; 21: First mass portion serving as a mass portion; 22: Second mass portion serving as a mass portion; 23: Third mass portion; 24: Support portion; 25: Beam portion serving as a rotation axis; 26: Opening; 28, 228: Connecting portion; 30: Cover; 100, 200: Physical quantity sensor; 229: Slit; 900: Composite sensor; 1100: Personal computer; 1200: Cell phone; 1300: Still digital camera; 1500: Automobile; 2000: Wrist device serving as a portable electronic device; 3000: Inertial measurement unit. DETAILED DESCRIPTION

[0062] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following drawings, the dimensions of each layer and each component are different from the actual dimensions in order to depict the dimensions of each layer and each component to a degree that allows identification.

[0063] In addition, Figure 1 、 Figure 2 、 Figures 9 to 12 and Figures 14 to 19 For ease of explanation, three axes, namely, the X-axis, the Y-axis, and the Z-axis, are shown, which are perpendicular to each other. The tip side of the arrow in the illustrated axial direction is referred to as the "+ side," and the base side is referred to as the "- side." Hereinafter, the direction parallel to the X-axis is referred to as the "X-axis direction," the direction parallel to the Y-axis is referred to as the "Y-axis direction," and the direction parallel to the Z-axis is referred to as the "Z-axis direction."

[0064] (Implementation Method)

[0065] <Structure of Physical Quantity Sensor>

[0066] Figure 1 It is a plan view schematically showing the physical quantity sensor according to the embodiment. Figure 2 yes Figure 1 First, refer to the AA line of the Figure 1 and Figure 2 The schematic structure of the physical quantity sensor 100 according to the embodiment will be described. Figure 1 In the figure, for the convenience of explanation, the cover 30 is omitted.

[0067] The physical quantity sensor 100 of this embodiment can be used, for example, as an inertial sensor. Specifically, for example, it can be used as an acceleration sensor (capacitive acceleration sensor, capacitive MEMS acceleration sensor) for measuring acceleration in the vertical direction (Z-axis direction). In addition, in this embodiment, the vertical direction is referred to as the Z-axis, the axial direction of the rotation axis (beam 25) described later is referred to as the Y-axis, and the direction intersecting both the Z-axis and the Y-axis is referred to as the X-axis.

[0068] like Figure 1 and Figure 2 As shown, the physical quantity sensor 100 includes a plate-shaped movable body 20 , a support substrate 10 that supports the movable body 20 , and a cover 30 that surrounds the movable body 20 together with the support substrate 10 .

[0069] The supporting substrate 10 has a concave cavity 16. On the main surface 17 in the cavity 16, there are provided first and second fixed electrodes 11 and 12, a dummy electrode 13, and a protrusion 15 as detection electrodes. Moreover, a support 14 for spacing and supporting the movable body 20 is provided between the first fixed electrode 11 and the second fixed electrode 12. In addition, protrusions 15 protruding toward the movable body 20 side (+Z axis side) are provided on both sides of the support 14 in the X-axis direction. The support 14 and the protrusion 15 are formed integrally with the supporting substrate 10. The material of the supporting substrate 10 is not particularly limited, but in this embodiment, as a preferred example, an insulating material, i.e., borosilicate glass (hereinafter referred to as glass) is used.

[0070] The first and second fixed electrodes 11 and 12 are provided on the support substrate 10. Specifically, the first fixed electrode 11 is located on the -X-axis side of the support column 14 when viewed from the side in the Y-axis direction, and is provided in a region facing and overlapping with the first mass unit 21 (described later) when viewed from above in the Z-axis direction. The second fixed electrode 12 is located on the +X-axis side of the support column 14 when viewed from the side in the Y-axis direction, and is provided in a region facing and overlapping with the second mass unit 22 (described later) when viewed from above in the Z-axis direction. The dummy electrode 13 is provided on the principal surface 17 other than the first and second fixed electrodes 11 and 12. Materials for the first and second fixed electrodes 11 and 12 and the dummy electrode 13 include, for example, Pt (platinum), Al (aluminum), Mo (molybdenum), Cr (chromium), Ti (titanium), Ni (nickel), Cu (copper), Ag (silver), Au (gold), or a conductive film such as ITO (indium tin oxide).

[0071] The physical quantity sensor 100 has a protrusion 15 on the main surface 17 of the supporting substrate 10 that limits the displacement of the movable body 20 to prevent the movable body 20 from being displaced (swinging) and contacting the supporting substrate 10 when an excessive acceleration is applied. The protrusion 15 is provided in an area where the first fixed electrode 11 is provided and an area where the second fixed electrode 12 is provided, and protrudes from the supporting substrate 10 toward the first and second mass portions 21 and 22. The protrusion 15 is formed in a cylindrical shape, and its diameter is approximately 3 to 5 μm. The displacement of the movable body 20 is suppressed by the protrusion 15, so the collision energy when the movable body 20 collides with the protrusion 15 is smaller than the collision energy when the end of the movable body 20 collides with the supporting substrate 10. As a result, the impact resistance of the movable body 20 is improved, and thus damage to the movable body 20 can be suppressed.

[0072] The movable body 20 includes a support portion 24 and a beam portion 25 serving as a rotation axis. The support portion 24 is fixed to the support column 14 and connected to the support substrate 10. The support portion 24 is formed into a rectangular shape that is long in the Y-axis direction, and two support portions 24 are provided in parallel with the beam portion 25 sandwiched between them. The two support portions 24 are connected together at their centers. The beam portion 25 is supported by the support portion 24 and extends from the center of the support portion 24 in the Y-axis direction. The beam portion 25 functions as a so-called torsion spring. The beam portion 25 supports the movable body 20 as a whole, allowing it to swing relative to the support substrate 10 via the support portion 24 and the support column 14.

[0073] Two mass units are arranged line-symmetrically with respect to the beam 25, which serves as the rotation axis. Specifically, the movable body 20 includes a first movable body 20a and a second movable body 20b. The first movable body 20a is located on the -X-axis side of the center line CL2, which serves as the rotation center of the beam 25. The second movable body 20b is located on the +X-axis side of the center line CL2, which serves as the rotation center of the beam 25. The first movable body 20a includes a first mass unit 21 and a third mass unit 23, which serve as mass units, arranged in sequence from the beam 25 toward the -X-axis. The second movable body 20b includes a second mass unit 22, which serves as a mass unit. The first and second mass units 21 and 22 are arranged symmetrically with respect to the center line CL2. When viewed from above in the Z-axis direction, the first mass unit 21 is located in a region overlapping the first fixed electrode 11, and the second mass unit 22 is located in a region overlapping the second fixed electrode 12.

[0074] The movable body 20 is supported by the beam 25 and can swing about the beam 25 as its axis of rotation. As the movable body 20 seesaws (tips) around the beam 25, the gap (distance) between the first mass unit 21 and the first fixed electrode 11, and the gap (distance) between the second mass unit 22 and the second fixed electrode 12, change. The physical quantity sensor 100 determines acceleration based on the changes in capacitances C1 and C2 between the first mass unit 21 and the first fixed electrode 11, and between the second mass unit 22 and the second fixed electrode 12, as the movable body 20 tilts.

[0075] Specifically, when vertical acceleration (Z-axis direction) (e.g., acceleration due to gravity) is applied to the movable body 20, rotational moments (force moments) are generated on each of the first movable body 20a and the second movable body 20b. If the rotational moments of the first movable body 20a (e.g., counterclockwise) and the second movable body 20b (e.g., clockwise) are balanced, the inclination of the movable body 20 does not change, and acceleration cannot be detected. Therefore, the movable body 20 is designed so that when vertical acceleration is applied, the rotational moments of the first movable body 20a and the second movable body 20b are unbalanced, resulting in a predetermined inclination of the movable body 20.

[0076] The physical quantity sensor 100 arranges the beam 25 at a position offset from the center of gravity of the movable body 20 in the X-axis direction. In other words, the third mass unit 23 is provided on the first movable body 20a. Therefore, the distance Ra from the center line CL2, which serves as the rotation axis of the beam 25, to the end surface of the first movable body 20a is different from the distance Rb from the center line CL2 to the end surface of the second movable body 20b. Consequently, the first movable body 20a and the second movable body 20b have different masses. That is, with the center line CL2 of the beam 25 as the starting point, the masses of one side of the movable body 20 (the first movable body 20a) and the other side (the second movable body 20b) are different. By making the masses of the first movable body 20a and the second movable body 20b different in this way, the rotational moment of the first movable body 20a and the rotational moment of the second movable body 20b generated when vertical acceleration is applied to the movable body 20 can be made unbalanced. Therefore, when acceleration in the vertical direction is applied to the physical quantity sensor 100 , the movable body 20 tilts.

[0077] A capacitor (variable capacitor) C1 is formed between the first mass unit 21 and the first fixed electrode 11. Furthermore, a capacitor (variable capacitor) C2 is formed between the second mass unit 22 and the second fixed electrode 12. The capacitor C1 changes depending on the gap (distance) between the first mass unit 21 and the first fixed electrode 11, while the capacitor C2 changes depending on the gap (distance) between the second mass unit 22 and the second fixed electrode 12.

[0078] For example, when the movable body 20 is horizontal relative to the support substrate 10, the capacitances C1 and C2 have approximately equal capacitance values. Specifically, when viewed from above in the Z-axis direction, the overlapping area between the first mass unit 21 and the first fixed electrode 11 and the overlapping area between the second mass unit 22 and the second fixed electrode 12 are equal. When viewed from the side in the Y-axis direction, the gap between the first mass unit 21 and the first fixed electrode 11 and the gap between the second mass unit 22 and the second fixed electrode 12 are equal. Therefore, the capacitance values of capacitors C1 and C2 are also equal. Furthermore, for example, if a vertical acceleration is applied to the movable body 20 and the movable body 20 tilts about the beam 25, the capacitance values of capacitors C1 and C2 change in response to the tilt of the movable body 20. When the movable body 20 tilts, the gap between the first mass unit 21 and the first fixed electrode 11 and the gap between the second mass unit 22 and the second fixed electrode 12 differ, resulting in different capacitance values for capacitors C1 and C2.

[0079] The movable body 20 is provided with a plurality of openings 26 that pass through the movable body 20 in the thickness direction to reduce the damping (flow resistance that attempts to prevent the movement of the movable body) caused by the viscosity of the gas when the movable body 20 is swung by applying an acceleration in the vertical direction to the movable body 20. The first, second mass portions 21, 22, and the third mass portion 23 of this embodiment, which serve as mass portions, have square openings 26 that pass through in a grid-like pattern. As a result, the damping of the movable body 20 is reduced and the sensitivity of detecting acceleration is improved. In addition, the plurality of openings 26 may also be of different shapes. In addition, the position and number of the configuration openings 26 can also be freely set.

[0080] The movable body 20 includes a connecting portion 28. The connecting portion 28 is connected to the beam portion 25, which serves as the rotation axis, and is provided in a direction intersecting the beam portion 25 (the X-axis direction). The connecting portion 28 is connected to the first mass unit 21 and the second mass unit 22. In other words, the connecting portion 28 extends from the beam portion 25 in both directions along the X-axis and connects to the first mass unit 21 and the second mass unit 22.

[0081] The material of the movable body 20 is not particularly limited, but in this embodiment, a conductive material, namely silicon, is preferably used. Using a conductive material for the movable body 20 allows the first mass unit 21 (the region overlapping with the first fixed electrode 11) and the second mass unit 22 (the region overlapping with the second fixed electrode 12) to function as electrodes. Alternatively, a non-conductive substrate may be used for the movable body, with the first and second mass units formed using a conductive electrode layer provided on the non-conductive substrate.

[0082] Next, the arrangement of the protrusions 15 will be described in detail.

[0083] In this embodiment, a plurality of protrusions 15 (two each) are provided on the first fixed electrode 11 overlapping with the first mass portion 21, and on the second fixed electrode 12 overlapping with the second mass portion 22. The plurality of protrusions 15 are provided on a straight line parallel to the beam portion 25 serving as the rotation axis. Thus, the impact received by the movable body 20 when it contacts the protrusions 15 can be dispersed. In addition, the protrusions 15 are provided at a position that is line-symmetrical at a distance R2 relative to the center line CL1, and the center line CL1 divides the movable body 20 into two equal parts in the axial direction (Y-axis direction) of the beam portion 25 serving as the rotation axis. Thus, when the first and second mass portions 21 and 22 contact the protrusions 15, the posture of the movable body 20 can be stabilized.

[0084] The protrusion 15 is provided at a position that is line-symmetrical with respect to the center line CL2, which is the rotation center of the beam portion 25, at a distance R1. By providing the protrusions 15 of the same height to be line-symmetrical with respect to the beam portion 25, the swing angles (rotation angles) of the first mass portion 21 and the second mass portion 22 that swing around the beam portion 25 can be made the same. This improves the accuracy of detecting the physical quantity of the physical quantity sensor 100. In addition, in the case where the protrusion 15 is provided at an asymmetric position relative to the beam portion 25, in order to make the swing angles of the first mass portion 21 and the second mass portion 22 the same, it is necessary to make the heights of the protrusions 15 different. In order to form protrusions 15 of different heights on the supporting substrate 10, the number of steps (the number of times the pattern is formed) for forming the protrusions 15 in the manufacturing method of the physical sensor described later increases, and production efficiency decreases. In the physical quantity sensor 100 of this embodiment, the protrusions 15 are provided line-symmetrically with respect to the beam portion 25 . Therefore, by using the protrusions 15 of the same height, the swing angles of the first mass portion 21 and the second mass portion 22 can be made the same.

[0085] Such protrusions 15 are provided at positions corresponding to the centers of the four openings 26 arranged in two rows and two columns. In other words, the protrusions 15 are provided at positions that do not coincide with the openings 26. Thus, the protrusions 15 contact the ends (edges) of the openings 26, thereby preventing damage to the first and second mass portions 21 and 22.

[0086] In addition, this embodiment shows a structure in which two protrusions 15 are provided in each region where the first and second fixed electrodes 11 and 12 are provided, but this is not limited to this. Alternatively, a structure may include one protrusion 15 in each region, or a structure may include three or more protrusions 15 in each region. Furthermore, while the protrusions 15 are described as cylindrical in shape, they may also be polygonal prisms such as triangular prisms or quadrangular prisms, or may be chamfered. Furthermore, an insulating protective film may be formed on the surface of the protrusions 15. This prevents electrical short circuits when the first and second mass portions 21 and 22 come into contact with the protrusions 15.

[0087] The position of the protrusion 15 in the X-axis direction will be described.

[0088] In this embodiment, in the cross direction (X-axis direction), the distance from the connection position between the connecting portion 28 and the first and second mass portions 21 and 22 to the ends of the first and second mass portions 21 and 22 on the opposite side of the beam portion 25 is set to L, and the distance from the protrusion 15 to the ends of the first and second mass portions 21 and 22 on the opposite side of the beam portion 25 is set to L1. In this case, the protrusion 15 is set in the range of L1=0.18L or more and 0.88L or less.

[0089] Figure 3 This is a diagram showing a beam load model for calculating the bending stress applied to the movable body. Figure 4 and Figure 5 This is a diagram showing the calculation results of the bending stress applied to the movable body. Figure 6 This is a graph showing the relationship between the position of the protrusion and the bending stress.

[0090] Next, the bending stress to which the movable body 20 is subjected when an excessive impact in the vertical direction is applied to the physical quantity sensor 100 will be described.

[0091] like Figure 3 As shown, when a large vertical impact is applied to the physical quantity sensor 100, ignoring the support portion 24, the beam portion 25, and the third mass portion 23, a beam model can be considered equivalent, with the protrusion 15 serving as a fulcrum and different distributed loads supported at both ends. Therefore, in the cross-direction (X-axis direction), the distance from the connection point between the connecting portion 28 and the first and second mass portions 21 and 22 to the ends of the first and second mass portions 21 and 22 opposite the beam portion 25 is defined as L, and the distance from the protrusion 15 to the ends of the first and second mass portions 21 and 22 opposite the beam portion 25 is defined as L1. The bending stress was calculated while varying the position of the protrusion 15, i.e., L1. The lengths of the connecting portion 28 and the first and second mass portions 21 and 22 were assumed to be constant. In the following description, the position L1 of the protrusion 15 may be expressed as the ratio (L1 / L) of the distance L from the connection point between the connecting portion 28 and the first and second mass units 21 and 22 to the ends of the first and second mass units 21 and 22 opposite the beam portion 25. The beam model used for calculations has a connecting portion 28 length of approximately 160 μm in the X-axis direction and a width of approximately 25 μm in the Y-axis direction. Furthermore, the first and second mass units have a length of approximately 200 μm and a thickness of approximately 30 μm in the Z-axis direction.

[0092] Figure 4 The bending stress calculation results shown are for a case where the protrusion 15 is located at the end portions of the first and second mass portions 21 and 22 on the opposite side from the beam portion 25 ( L1 / L=0).

[0093] Figure 5 The bending stress calculation results shown are for a case where the protrusion 15 is located substantially in the center of the first and second mass portions 21 and 22 (L1 / L=0.51).

[0094] Figure 4 and Figure 5 The horizontal axis represents Figure 3 In the beam model shown, the distance from the beam portion 25 (rotation axis) is the distance from the center of the connecting portion 28. In addition, the triangular mark in the figure indicates the position of the protrusion 15. Figure 4 and Figure 5 The vertical axis represents Figure 3The bending stress generated in each part of the beam model when a load of 4500G is applied from the vertical direction. Figure 3 The arrows shown indicate the direction of the load. Figure 4 and Figure 5 As can be seen from the comparison, by moving the position of protrusion 15 from L1 / L = 0 to L1 / L = 0.51, the bending stress applied to connection portion 28 is reduced from 4.0 MPa to 0.2 MPa. Furthermore, a load of 4500 G corresponds to the maximum impact when excessive acceleration is applied to physical quantity sensor 100, causing movable body 20 to collide with protrusion 15.

[0095] Figure 6 The horizontal axis represents the position of the protrusion 15 as a ratio of L1 / L. Figure 6 The vertical axis represents the maximum bending stress applied to the connecting portion 28 of the beam model.

[0096] Figure 7 and Figure 8 This is a diagram showing the shape of the beam model's displacement when a load is applied. Figure 6 The vertical axis is represented by positive (+) stress values. Figure 7 The figure shows the situation where compressive stress is generated on the surface of the beam model (the surface on the +Z axis side) and tensile stress is generated on the back surface of the beam model (the surface on the -Z axis side). In addition, the negative (-) stress value indicates the situation where Figure 8 The figure shows a situation where tensile stress is generated on the front surface (the surface on the +Z axis side) of the beam model and compressive stress is generated on the back surface (the surface on the -Z axis side) of the beam model. The triangle marks in the figure indicate the approximate positions of the protrusions 15, and the directions of the arrows in the figure indicate the directions of stress on the front and back surfaces of the beam model.

[0097] from Figure 6 It can be seen that the closer the position of the protrusion 15 is to L1=0.5L, the smaller the bending stress applied to the connecting portion 28. The inventors conducted an impact resistance test using a sample in which the position of the protrusion 15 was L1=0.18L and found that no defects occurred in the physical quantity sensor 100. The bending stress generated by the beam model when the position of the protrusion 15 was L1=0.18L was 2.4 MPa. Similarly, using a sample in which the position of the protrusion 15 was L1=0.88L, the same result of a bending stress of -2.4 MPa was obtained. Therefore, the physical quantity sensor 100 of this embodiment is provided in a range in which the protrusion 15 is above L1=0.18L and below L1=0.88L. As a result, damage generated at the boundary between the connecting portion 28 and the first and second mass portions 21 and 22 can be suppressed. The position of the protrusion 15 is preferably L1 = 0.4L or more and L1 = 0.6L or less where the bending stress is ±1.0 MPa, and more preferably L1 = 0.5L where the bending stress is substantially minimum.

[0098] Figures 9 to 12 This is a cross-sectional view schematically showing the operation of the physical quantity sensor. Figures 9 to 12 To illustrate the relationship between the operation of the physical quantity sensor and capacitance. Figures 9 to 12 In the figure, the structures not necessary for the description of the operation are omitted.

[0099] Figure 9 The movable body 20 is shown in a state substantially horizontal with respect to the support substrate 10. A case where an acceleration αu in the +Z-axis direction is applied to the physical quantity sensor 100 in this state will be described.

[0100] The movable body 20 is formed into a flat rectangular shape with a uniform thickness (dimension in the Z-axis direction). The first movable body 20a has a mass m1, and its center of gravity G1 is located at a distance r1 in the -X-axis direction from the center Q of the beam portion 25 supported so as to be rotatable relative to the support portion 24. The second movable body 20b has a mass m2, and its center of gravity G2 is located at a distance r2 in the +X-axis direction from the center Q of the beam portion 25. The first movable body 20a has a third mass portion 23, which is formed into a rectangular shape that is longer in the X-axis direction than the second movable body 20b. Therefore, the mass m1 of the first movable body 20a is heavier than the mass m2 of the second movable body 20b, and the distance r1 at which the center of gravity G1 of the first movable body 20a is located is longer than the distance r2 at which the center of gravity G2 of the second movable body 20b is located.

[0101] When an acceleration αu from the -Z-axis direction toward the +Z-axis direction is applied to the physical quantity sensor 100, a first rotational moment Nu1, which corresponds to the product of mass m1, acceleration αu, and distance r1, acts counterclockwise on the first movable body 20a with the center Q of the beam 25 as the rotation axis. Meanwhile, a second rotational moment Nu2, which corresponds to the product of mass m2, acceleration αu, and distance r2, acts clockwise on the second movable body 20b with the center Q of the beam 25 as the rotation axis. The mass m1 of the first movable body 20a is heavier than the mass m2 of the second movable body 20b, and the distance r1 between the center of gravity G1 of the first movable body 20a and the center of gravity G2 of the second movable body 20b is greater than the distance r2 between the center of gravity G2 of the second movable body 20b. Therefore, the first rotational moment Nu1 acting on the first movable body 20a is greater than the second rotational moment Nu2 acting on the second movable body 20b.

[0102] Therefore, if Figure 10 As shown, it is equivalent to the first rotation moment Nu1 (refer to Figure 9 ) and the second rotational moment Nu2 (refer to Figure 9) acts on the beam 25 counterclockwise about the center Q of the beam 25 as the rotation axis, causing the movable body 20 to tilt counterclockwise. As a result, the gap between the first mass portion 21 of the first movable body 20a and the first fixed electrode 11 decreases (narrows), increasing the capacitance of the capacitor C1 formed between the first mass portion 21 and the first fixed electrode 11. Meanwhile, the gap between the second mass portion 22 of the second movable body 20b and the second fixed electrode 12 increases (widens), decreasing the capacitance of the capacitor C2 formed between the second mass portion 22 and the second fixed electrode 12.

[0103] Figure 11 The movable body 20 is shown in a state substantially horizontal with respect to the support substrate 10. A case where an acceleration αd in the −Z-axis direction is applied to the physical quantity sensor 100 in this state will be described.

[0104] When an acceleration αd from the +Z-axis direction toward the -Z-axis direction is applied to the physical quantity sensor 100, a first rotational moment Nd1, corresponding to the product of mass m1, acceleration αd, and distance r1, acts on the first movable body 20a in a clockwise direction about the center Q of the beam 25. Meanwhile, a second rotational moment Nd2, corresponding to the product of mass m2, acceleration αd, and distance r2, acts on the second movable body 20b in a counterclockwise direction about the center Q of the beam 25. The mass m1 of the first movable body 20a is heavier than the mass m2 of the second movable body 20b, and the distance r1 between the center of gravity G1 of the first movable body 20a and the center of gravity G2 of the second movable body 20b is greater than the distance r2 between the center of gravity G2 of the second movable body 20b. Therefore, the first rotational moment Nd1 acting on the first movable body 20a is greater than the second rotational moment Nd2 acting on the second movable body 20b.

[0105] Therefore, if Figure 12 As shown, it is equivalent to the first rotation moment Nd1 (refer to Figure 11 ) and the second rotational moment Nd2 (refer to Figure 11 ) acts on the beam 25 in a clockwise direction about the center Q of the beam 25 as the rotation axis, causing the movable body 20 to tilt in a clockwise direction. As a result, the gap between the first mass unit 21 of the first movable body 20a and the first fixed electrode 11 increases (widens), reducing the capacitance C1 formed between the first mass unit 21 and the first fixed electrode 11. Conversely, the gap between the second mass unit 22 of the second movable body 20b and the second fixed electrode 12 decreases (narrows), increasing the capacitance C2 formed between the second mass unit 22 and the second fixed electrode 12.

[0106] In the physical quantity sensor 100, the movable body 20 can be tilted to a greater extent by increasing the moments Nu and Nd acting on the beam 25. Specifically, by amplifying the mass difference between the first movable body 20a and the second movable body 20b, and by amplifying the difference between the distance r1 from the beam 25 to the center of gravity G1 of the first movable body 20a and the distance r2 from the beam 25 to the center of gravity G2 of the second movable body 20b. This increases the degree of increase or decrease in the capacitance values of the capacitors C1 and C2, thereby improving the sensitivity of the physical quantity sensor 100 in detecting physical quantities. Furthermore, the physical quantity sensor 100 can achieve a greater degree of tilting of the movable body 20 by narrowing the width of the beam 25 in the X-axis direction, which functions as a torsion spring, thereby reducing the toughness of the spring. This also improves the detection sensitivity of the physical quantity.

[0107] Furthermore, in this embodiment, the movable body 20 is described as being capable of swinging by the beam portion 25 supported by the support pillars 14 or the like provided on the support substrate 10, but the present invention is not limited to this configuration. For example, the movable body may be configured such that, when viewed from above in the Z-axis direction, the movable body is capable of swinging by a beam portion extending in the Y-axis direction from a frame-shaped support body that surrounds the outer periphery of the movable body and is provided at a predetermined distance from the movable body.

[0108] <Method for Manufacturing Physical Quantity Sensor>

[0109] Figure 13 This is a flowchart illustrating a manufacturing process of a physical quantity sensor. Figures 14 to 18 It is a cross-sectional view of each manufacturing process of the physical quantity sensor. Figures 13 to 18 A method of manufacturing the physical quantity sensor 100 will be described.

[0110] Step S1 is a support substrate forming process for forming the support substrate 10 and the protrusion 15. First, a glass substrate is prepared. In the support substrate forming process, the support substrate 10 and the protrusion 15 are formed by patterning the glass substrate using photolithography and etching techniques. For example, the glass substrate can be wet-etched using a fluoric acid etchant. Thus, Figure 14 The support substrate 10 shown has a concave cavity 16 , a support column 14 , and a protrusion 15 formed on a glass substrate.

[0111] Step S2 is a fixed electrode forming step for forming the first and second fixed electrodes 11 and 12 and the dummy electrode 13. In the fixed electrode forming step, after a conductive film is formed on the main surface 17 of the support substrate 10 by sputtering or the like, the first and second fixed electrodes 11 and 12 and the dummy electrode 13 are formed by patterning the conductive film using photolithography and etching techniques (dry etching, wet etching, etc.). Figure 15As shown, the first and second fixed electrodes 11 and 12 and the dummy electrode 13 can be provided on the main surface 17 of the support substrate 10 in the cavity 16 .

[0112] Step S3 is a substrate bonding process for bonding the support substrate 10 and the silicon substrate 20S. Figure 16 As shown, in the substrate bonding step, the support substrate 10 and the silicon substrate 20S are bonded using, for example, anodic bonding, direct bonding, or an adhesive.

[0113] Step S4 is a movable body forming process for forming the movable body 20 having the opening 26 from the silicon substrate 20S. In the movable body forming process, for example, the silicon substrate 20S is ground using a grinder to thin the silicon substrate 20S to a predetermined thickness. Then, the movable body 20 is formed by patterning the silicon substrate 20S using photolithography and etching techniques. For example, the silicon substrate 20S can be etched by a Bosch process using an RIE (Reactive Ion Etching) device. Thus, as shown in FIG. Figure 17 As shown, the movable body 20 including the opening 26 , the support portion 24 , and the beam portion 25 is formed as one body.

[0114] Step S5 is a sealing process for sealing the movable body 20. In the sealing process, the cover 30 is bonded to the support substrate 10, and the movable body 20 is accommodated in the space formed by the support substrate 10 and the cover 30. The support substrate 10 and the cover 30 are bonded using, for example, anodic bonding or adhesive. Figure 18 As shown, a physical quantity sensor 100 can be obtained. When anodic bonding is used in the sealing step, by forming a dummy electrode 13 having the same potential as the silicon substrate 20S on the main surface 17 of the support substrate 10 other than the first and second fixed electrodes 11 and 12, it is possible to prevent the movable body 20 from adhering to the support substrate 10 due to electrostatic force.

[0115] As described above, according to the physical quantity sensor 100 of this embodiment, the following effects can be obtained.

[0116] The movable body 20 of the physical quantity sensor 100 includes first and second mass units 21 and 22, a beam 25, and a connecting portion 28. The first and second mass units 21 and 22 are connected to the connecting portion 28, which is connected to the beam 25 and arranged in a direction intersecting the beam 25. The movable body 20 swings about the beam 25 as its rotation axis. Furthermore, a protrusion 15 is provided on the support substrate 10, which supports the movable body 20 with a gap therebetween. In the intersecting direction (X-axis direction), the distance from the connection point between the connecting portion 28 and the first and second mass units 21 and 22 to the ends of the first and second mass units 21 and 22 opposite the beam 25 is defined as L, and the distance from the protrusion 15 to the ends of the first and second mass units 21 and 22 opposite the beam 25 is defined as L1. The protrusion 15 is provided within the range of L1 = 0.18L to 0.88L. As a result, the bending stress applied to the connection portion 28 is reduced to 0.6 times that when the protrusions 15 are located at the ends of the first and second mass portions 21 and 22. This reduces damage at the boundaries between the connection portion 28 and the first and second mass portions 21 and 22. Consequently, a physical quantity sensor 100 having excellent shock resistance and improved reliability can be provided.

[0117] Multiple protrusions 15 are provided on the first fixed electrode 11, which overlaps with the first mass unit 21, and the second fixed electrode 12, which overlaps with the second mass unit 22. These protrusions 15 are arranged on a straight line parallel to the beam 25, which serves as the rotation axis. This helps disperse the impact received by the movable body 20 when the protrusions 15 come into contact.

[0118] The protrusions 15 are provided at positions symmetrically spaced apart by a distance R2 from the center line CL1 that bisects the movable body 20 along the axis of the beam 25, which serves as the rotation axis. This stabilizes the posture of the movable body 20 when the first and second mass portions 21 and 22 contact the protrusions 15.

[0119] The protrusions 15 are provided at positions corresponding to the centers of the four openings 26 arranged in two rows and two columns. In other words, the protrusions 15 are provided at positions that do not coincide with the openings 26. Thus, the protrusions 15 contact the ends (edges) of the openings 26, thereby preventing damage to the first and second mass portions 21 and 22.

[0120] The protrusions 15 are arranged symmetrically with respect to the center line CL2, the center of rotation of the beam 25. This allows the first and second mass units 21 and 22 to have the same swing angle using the protrusions 15 of the same height. This improves the accuracy of detecting the physical quantity of the physical quantity sensor 100. Furthermore, if the protrusions 15 are arranged asymmetrically with respect to the beam 25, the protrusions 15 must have different heights to make the swing angles of the first and second mass units 21 and 22 the same. Forming protrusions 15 of different heights increases the number of steps required to form the protrusions 15, reducing production efficiency. By arranging the protrusions 15 symmetrically with respect to the beam 25, the first and second mass units 21 and 22 can have the same swing angle using protrusions 15 of the same height. Therefore, the physical quantity sensor 100, in which the protrusions 15 make the swing angles of the first and second mass units 21 and 22 the same, can be manufactured efficiently.

[0121] In addition, the present invention is not limited to the above-described embodiment, and various changes and improvements can be made to the above-described embodiment.

[0122] (Variation)

[0123] Figure 19 It is a plan view schematically showing a physical quantity sensor according to a modified example. Figure 20 This figure shows the calculation results of the bending stress applied to the movable body. A physical quantity sensor 200 according to a modified example is described below. Components identical to those in the embodiment are denoted by the same reference numerals, and duplicate descriptions are omitted. The physical quantity sensor 200 according to this modified example differs from the physical quantity sensor 100 described in the embodiment in the length of the connecting portion 28.

[0124] like Figure 19 As shown, the movable body 20 of the physical quantity sensor 200 includes a connecting portion 228. The movable body 20 has slits 229 between the connecting portion 228 and the first mass unit 21, and between the connecting portion 228 and the second mass unit 22. The slits 229 extend from the support portion 24 in the X-axis direction. In other words, the length of the connecting portion 228 in this embodiment in the X-axis direction is extended in both directions by the slit 229 and the long side of the movable body 20 in the Y-axis direction. Specifically, the connecting portion 228 of the physical quantity sensor 200 of this modified example is extended to 220 μm, which is approximately 1.4 times the length of the connecting portion 28 of the physical quantity sensor 100 described in the embodiment, which is 160 μm.

[0125] Figure 20 The bending stress calculation results shown are in Figure 3 The beam model shown shows the result when the connection portion 28 (228) is set to 220 μm and the position of the protrusion 15 is set to L1 / L=0. Figure 4 and Figure 20 As can be seen from the comparison, the bending stress applied to the connecting portion 228 is reduced from 4.0 MPa to 2.4 MPa by extending the length of the connecting portion 228. Therefore, by providing the slit 229 and extending the length of the connecting portion 228, the bending stress applied to the connecting portion 228 can be further reduced.

[0126] (Compound Sensor)

[0127] Next, refer to Figure 21 A configuration example of a composite sensor including the above-described physical quantity sensor 100 will be described. Figure 21 This is a functional block diagram showing the schematic structure of a composite sensor.

[0128] like Figure 21 As shown, composite sensor 900 includes the aforementioned acceleration sensor (physical quantity sensor 100) for measuring acceleration in the Z-axis direction, acceleration sensor (physical quantity sensor 101) for measuring acceleration in the X-axis direction, acceleration sensor (physical quantity sensor 102) for measuring acceleration in the Y-axis direction, and angular velocity sensor 103. Angular velocity sensor 103 can efficiently and accurately detect the angular velocity in a desired uniaxial direction. Alternatively, angular velocity sensor 103 may include three angular velocity sensors 103, one corresponding to each axial direction, to measure angular velocity in three axial directions. In addition, the composite sensor 900 can have IC40a, which includes, for example, a driving circuit for driving the physical quantity sensors 100, 101, 102 and the angular velocity sensor 103, a detection circuit (signal processing unit 45a) for detecting the acceleration and angular velocity in the directions of the X-axis, Y-axis and Z-axis based on the signals from the physical quantity sensors 100, 101, 102 and the angular velocity sensor 103, an output circuit (output unit 46a) for converting the signal from the detection circuit into a predetermined signal and outputting it, etc.

[0129] In this manner, the composite sensor 900 can be easily configured using the physical quantity sensors 100 , 101 , and 102 and the angular velocity sensor 103 , and a plurality of physical quantity data, such as acceleration data and angular velocity data, can be easily obtained using one sensor.

[0130] (Inertial Measurement Unit)

[0131] Next, refer to Figure 22 and Figure 23 Let's explain the inertial measurement unit (IMU: Inertial Measurement Unit). Figure 22 This is an exploded perspective view showing the schematic structure of an inertial measurement unit. Figure 23 This is a perspective view showing an example of arrangement of inertial sensor elements of an inertial measurement unit.

[0132] like Figure 22 As shown, inertial measurement unit 3000 is composed of outer housing 301, joint member 310, and sensor assembly 325 including an inertial sensor element. In other words, sensor assembly 325 is fitted (inserted) into interior 303 of outer housing 301 via joint member 310. Sensor assembly 325 is composed of inner housing 320 and substrate 315. For ease of understanding, the parts are referred to as outer housing and inner housing, but they can also be referred to as first housing and second housing.

[0133] The outer shell 301 is a pedestal formed by cutting aluminum into a box shape. The material is not limited to aluminum; other metals such as zinc and stainless steel, resins, or composite materials of metal and resin may also be used. The outer shell 301 has the same overall shape as the aforementioned inertial measurement unit 3000, being a rectangular parallelepiped that is roughly square when viewed from above, with through holes (without perforations) 302 formed near two vertices located in the diagonal direction of the square. Furthermore, the outer shell is not limited to through holes (without perforations) 302; for example, a structure may be provided in which notches are formed that allow screws to be threadedly fastened (a structure in which notches are formed at the corners of the outer shell 301 where the through holes (without perforations) 302 are located) and the outer shell is threadedly fastened. Alternatively, a structure may be provided in which flanges (ears) are formed on the side surfaces of the outer shell 301 and the flanges are threadedly fastened.

[0134] The outer shell 301 is a box-shaped, lidless rectangular parallelepiped. Its interior 303 (inner side) forms an internal space (container) enclosed by a bottom wall 305 and side walls 304. In other words, the outer shell 301 is shaped like a box with an open surface on the surface facing the bottom wall 305. The sensor assembly 325 is housed in a manner that covers substantially all of the opening of the open surface (blocking the opening), leaving the sensor assembly 325 exposed from the opening (not shown). The open surface facing the bottom wall 305 is the same surface as the upper surface 307 of the outer shell 301. Furthermore, the interior 303 of the outer shell 301, when viewed from above, is a hexagonal shape obtained by chamfering the corners of two vertices of a square. These chamfered vertices correspond to the positions of the through-holes (non-perforated) 302. Furthermore, in the cross-sectional shape (thickness direction) of the interior 303, a first joint surface 306, serving as the bottom wall, is formed on the bottom wall 305, at the periphery of the interior 303, i.e., within the internal space, and is one level higher than the central portion. Specifically, the first joint surface 306 is a portion of the bottom wall 305, a stepped portion that surrounds the central portion of the bottom wall 305 in a plan view and forms an annular, one-level ring. This surface is closer to the opening surface (the same surface as the upper surface 307) than the bottom wall 305.

[0135] Furthermore, while the outer shape of the outer shell 301 is described as an example of a box-like shape with a substantially square planar shape and no lid, the outer shape of the outer shell 301 is not limited to this. The planar shape of the outer shell 301 may also be a polygonal shape, such as a hexagon or octagon, with chamfered corners at the vertices of the polygon, or a planar shape with curved sides. Furthermore, the planar shape of the interior 303 (inside) of the outer shell 301 is not limited to the aforementioned hexagonal shape, but may also be a square (quadrilateral), an octagon, or other polygonal shape. Furthermore, the outer shape of the outer shell 301 and the planar shape of the interior 303 may or may not be similar.

[0136] The inner shell 320 is a component of the support substrate 315 and is shaped to be housed in the interior 303 of the outer shell 301. Specifically, in a plan view, it is a hexagonal shape obtained by chamfering the corners of the two vertices of a square. The inner shell 320 has a rectangular through-hole, i.e., an opening 321, and a recess 331 provided on one side of the support substrate 315. The two chamfered vertices correspond to the positions of the through-hole (no pits) 302 of the outer shell 301. The height in the thickness direction (Z-axis direction) is lower than the height from the upper surface 307 of the outer shell 301 to the first joint surface 306. In a preferred embodiment, the inner shell 320 is also formed by cutting aluminum, but other materials can also be used as with the outer shell 301.

[0137] A guide pin and a support surface (both not shown) for positioning the substrate 315 are formed on the back side of the inner housing 320 (the surface on the outer housing 301 side). The substrate 315 is set (positioned and assembled) on the guide pin and the support surface and adhered to the back side of the inner housing 320. In addition, the details of the substrate 315 will be described later. The peripheral edge portion of the back side of the inner housing 320 becomes a second bonding surface 322 composed of an annular plane. In a top view, the second bonding surface 322 is roughly the same shape as the first bonding surface 306 of the outer housing 301. When the inner housing 320 is set on the outer housing 301, the two surfaces face each other in a state of clamping the bonding component 310. In addition, the structure of the outer housing 301 and the inner housing 320 is an embodiment and is not limited to this structure.

[0138] Reference Figure 23 The structure of the substrate 315 on which the inertial sensor is mounted is described below. Figure 23 As shown, substrate 315 is a multilayer substrate having multiple through-holes formed therein, and a glass epoxy substrate (glass epoxy substrate) is used. Furthermore, the substrate is not limited to a glass epoxy substrate and may be a rigid substrate capable of mounting multiple inertial sensors, electronic components, connectors, etc. For example, a composite substrate or a ceramic substrate may also be used.

[0139] Connector 316, angular velocity sensor 317z, and acceleration detection unit 1, including the aforementioned acceleration sensor for measuring acceleration in the Z-axis direction (physical quantity sensor 100), are mounted on the surface of substrate 315 (the surface facing inner housing 320). Connector 316 is a male plug-in connector with two rows of connection terminals spaced evenly along the X-axis. Preferably, the connection terminals have 10 pins in one row and 20 pins in two rows, but the number of terminals can be adjusted appropriately based on design specifications.

[0140] Angular velocity sensor 317z, serving as an inertial sensor, is a gyroscopic sensor that detects angular velocity in the Z-axis direction. A preferred example is a vibrating gyroscopic sensor that uses crystal as a vibrator and detects angular velocity based on the complementary force applied to a vibrating object. Furthermore, the sensor is not limited to a vibrating gyroscopic sensor; any sensor capable of detecting angular velocity is also acceptable. For example, a sensor using ceramic or silicon as a vibrator may also be used.

[0141] Furthermore, an angular velocity sensor 317x for detecting the angular velocity of one axis in the X-axis direction is mounted on the side surface of the substrate 315 in the X-axis direction, with the mounting surface (mounting surface) being orthogonal to the X-axis. Similarly, an angular velocity sensor 317y for detecting the angular velocity of one axis in the Y-axis direction is mounted on the side surface of the substrate 315 in the Y-axis direction, with the mounting surface (mounting surface) being orthogonal to the Y-axis.

[0142] In addition, the angular velocity sensors 317x, 317y, and 317z are not limited to a structure using three angular velocity sensors corresponding to each axis of the X-axis, Y-axis, and Z-axis, but can also be sensors that can detect the angular velocity of the three axes. For example, a sensor device that can detect (probe) the angular velocity of the three axes using one device (package) can also be used.

[0143] The acceleration detection unit 1 includes at least the above-mentioned acceleration sensor for measuring the acceleration in the Z-axis direction, namely the physical quantity sensor 100. As needed, it can detect the acceleration in one axis direction (for example, the Z-axis direction), two axis directions (for example, the Z-axis, the Y-axis, or the X-axis, the Y-axis), or three axis directions (the X-axis, the Y-axis, and the Z-axis).

[0144] A control IC 319, serving as the control unit, is mounted on the back side of substrate 315 (the side facing the outer shell 301). This IC is a microcontroller unit (MCU) with a built-in storage unit including nonvolatile memory, an A / D converter, and other components, controlling various components of the inertial measurement unit 3000. The storage unit stores programs that define the sequence and content for detecting acceleration and angular velocity, programs that digitize the detected data and embed it into data packets, and associated data. Furthermore, a number of other electronic components are mounted on substrate 315.

[0145] According to such inertial measurement unit 3000 , since acceleration detection unit 1 including physical quantity sensor 100 is used, inertial measurement unit 3000 having excellent shock resistance and improved reliability can be provided.

[0146] (Portable Electronic Devices)

[0147] Next, based on Figure 24 and Figure 25 A detailed description will be given of a portable electronic device using the physical quantity sensor 100. In the following description, a wristwatch-type activity tracker will be described as an example of a portable electronic device.

[0148] like Figure 24 As shown, wrist device 2000, a wristwatch-type activity tracker, is attached to a user's wrist or other part (detected object) via straps 62 and 67. It includes a digital display unit 150 and is capable of wireless communication. The physical quantity sensor 100 of the present invention described above is embedded in wrist device 2000 as either a sensor for measuring acceleration or a sensor for measuring angular velocity.

[0149] The wrist device 2000 includes: a housing 60 that houses at least the physical quantity sensor 100; a processing unit 190 (see FIG. 1 ) that is housed in the housing 60 and processes output data from the physical quantity sensor 100; and Figure 25 ); a display unit 150 housed in the housing 60; and a light-transmitting cover 71 that blocks the opening of the housing 60. A focusing ring 78 is provided on the outside of the housing 60 of the light-transmitting cover 71 of the housing 60. A plurality of operation buttons 80, 81 are provided on the side of the housing 60. Figure 25 , further details are provided.

[0150] The acceleration sensor 113 included in the physical quantity sensor 100 detects accelerations in three mutually intersecting (ideally orthogonal) directions and outputs signals (acceleration signals) corresponding to the magnitude and direction of the three detected accelerations. Furthermore, the angular velocity sensor 114 detects angular velocities in three mutually intersecting (ideally orthogonal) axial directions and outputs signals (angular velocity signals) corresponding to the magnitude and direction of the detected angular velocities in the three axes.

[0151] The liquid crystal display (LCD) constituting the display unit 150 displays information corresponding to various detection modes, such as position information using the GPS sensor 110 and the geomagnetic sensor 111, movement information such as movement amount using the acceleration sensor 113 and the angular velocity sensor 114 included in the physical quantity sensor 100, biological information such as the pulse rate using the pulse sensor 115, or time information such as the current time. Furthermore, the ambient temperature using the temperature sensor 116 may also be displayed.

[0152] Communication unit 170 performs various controls to establish communication between the user terminal and an information terminal (not shown). Communication unit 170 is, for example, a transceiver compatible with short-range wireless communication standards such as Bluetooth (registered trademark) (including BTLE: Bluetooth Low Energy), Wi-Fi (registered trademark) (Wireless Fidelity), Zigbee (registered trademark), NFC (Near Field Communication), or ANT+ (registered trademark). Communication unit 170 also includes a connector compatible with communication bus standards such as USB (Universal Serial Bus).

[0153] The processing unit 190 (processor) is comprised of, for example, an MPU (Micro Processing Unit), a DSP (Digital Signal Processor), or an ASIC (Application Specific Integrated Circuit). The processing unit 190 performs various processes based on programs stored in the storage unit 140 and signals input from the operating unit 120 (e.g., operating buttons 80 and 81). Processing performed by the processing unit 190 includes data processing of output signals from the GPS sensor 110, geomagnetic sensor 111, pressure sensor 112, acceleration sensor 113, angular velocity sensor 114, pulse sensor 115, temperature sensor 116, and timer unit 130; display processing for causing the display unit 150 to display an image; sound output processing for causing the sound output unit 160 to output sound; communication processing for communicating with an information terminal (not shown) via the communication unit 170; and power control processing for supplying power from the battery 180 to various components.

[0154] Such a wrist device 2000 can have at least the following functions.

[0155] 1. Distance: The total distance from the start of measurement is measured using the high-precision GPS function.

[0156] 2. Pace: Displays the current walking pace based on the pace distance measurement.

[0157] 3. Average speed: Calculates the average speed from the start of average speed walking to the present and displays it.

[0158] 4. Altitude: Measure and display the altitude through GPS function.

[0159] 5. Stride length: Stride length is measured and displayed even in tunnels, where GPS signals cannot reach.

[0160] 6. Interval: Measure the number of steps in one minute and display it.

[0161] 7. Heart rate: Measure and display the heart rate through the pulse sensor.

[0162] 8. Slope: Measure and display the slope of the ground during mountain training or trail running.

[0163] 9. Automatic reciprocating: Automatically perform reciprocating measurement after walking a certain distance or a certain time set in advance.

[0164] 10. Exercise calories consumed: Displays calories consumed.

[0165] 11. Steps: Displays the total number of steps taken since the start of exercise.

[0166] In addition, the wrist device 2000 can be widely used in running watches, runners' watches, runners' watches corresponding to multiple sports such as duathlon and triathlon, outdoor watches, and GPS watches equipped with a satellite positioning system such as GPS.

[0167] In the above description, the GPS (Global Positioning System) is used as the satellite positioning system. However, other global navigation satellite systems (GNSS) may also be used. For example, one or more satellite positioning systems such as EGNOS (European Geostationary-Satellite Navigation Overlay Service), QZSS (Quasi Zenith Satellite System), GLONASS (Global Navigation Satellite System), GALILEO (Galileo Satellite Navigation System), and BeiDou (BeiDou Navigation Satellite System) may be used. Furthermore, a geostationary satellite-based satellite navigation augmentation system (SBAS) such as WAAS (Wide Area Augmentation System) or EGNOS (European Geostationary-Satellite Navigation Overlay Service) may be used as at least one of the satellite positioning systems.

[0168] Such a portable electronic device (wrist device 2000 ) includes the physical quantity sensor 100 and the processing unit 190 , and therefore has excellent reliability such as impact resistance.

[0169] (Electronic equipment)

[0170] Next, refer to Figures 26 to 28 An electronic device including the physical quantity sensor 100 according to the embodiment of the present invention will be described.

[0171] Figure 26This is a perspective diagram schematically illustrating the structure of a mobile (or notebook) personal computer, an electronic device equipped with a physical quantity sensor according to an embodiment of the present invention. In this diagram, personal computer 1100 comprises a main body 1104 equipped with a keyboard 1102 and a display unit 1106 equipped with a display unit 1000. Display unit 1106 is rotatably supported relative to main body 1104 via a hinge structure. Personal computer 1100 incorporates a physical quantity sensor 100, which functions as an acceleration sensor, and the like. A control unit (not shown) can perform control functions such as posture control based on detection signals from physical quantity sensor 100.

[0172] Figure 27 This is a perspective diagram schematically illustrating the structure of a mobile phone (including a PHS), an electronic device equipped with a physical quantity sensor according to an embodiment of the present invention. In this diagram, a mobile phone 1200 includes a plurality of operation buttons 1202, a listening port 1204, and a speaking port 1206. A display unit 1000 is disposed between the operation buttons 1202 and the listening port 1204. This mobile phone 1200 incorporates a physical quantity sensor 100, which functions as an acceleration sensor, for example. A control unit (not shown) can recognize the posture and movement of the mobile phone 1200 based on detection signals from the physical quantity sensor 100, change the image displayed on the display unit 1000, emit warning sounds or sound effects, and drive a vibration motor to vibrate the main body.

[0173] Figure 28 This is a perspective diagram schematically illustrating the configuration of a digital still camera, an electronic device equipped with a physical quantity sensor according to an embodiment of the present invention. Connections to external devices are also simplified in this diagram. While conventional film cameras use a light image of a subject to expose silver halide photographic film, the digital still camera 1300 uses an imaging element such as a CCD (Charge Coupled Device) to photoelectrically convert the light image of the subject and generate an image signal (image signal).

[0174] A display unit 1000 is provided on the back of a housing (main body) 1302 of a still digital camera 1300. This unit displays images based on the shooting signals generated by the CCD, functioning as a viewfinder that displays an electronic image of the subject. Furthermore, a light receiving unit 1304, including an optical lens (shooting optical system), a CCD, and the like, is provided on the front side (the back side in the figure) of the housing 1302.

[0175] When the photographer confirms the subject image displayed on the display unit 1000 and presses the shutter button 1306, the CCD image signal at that point in time is transmitted to and stored in the memory 1308. Furthermore, this still digital camera 1300 includes a video signal output terminal 1312 and a data communication input / output terminal 1314 on the side of the housing 1302. As shown in the figure, the video signal output terminal 1312 can be connected to a television monitor 1430, and the data communication input / output terminal 1314 can be connected to a personal computer 1440 as needed. Furthermore, through predetermined operations, the image signal stored in the memory 1308 is output to the television monitor 1430 and the personal computer 1440. This still digital camera 1300 incorporates a physical quantity sensor 100 functioning as an acceleration sensor, etc., and a control unit (not shown) can perform control such as image stabilization based on the detection signal from the physical quantity sensor 100.

[0176] The electronic devices 1100 , 1200 , and 1300 described above include the physical quantity sensor 100 that can improve reliability.

[0177] In addition, the physical quantity sensor 100 according to the embodiment of the present invention can be applied to Figure 26 Personal computer 1100 (mobile personal computer), Figure 27 Mobile phone 1200, Figure 28 In addition to the still digital camera 1300, the present invention can also be applied to electronic equipment such as inkjet ejection devices (such as inkjet printers), portable personal computers, televisions, video recorders, tape recorders, car navigation devices, pagers, electronic notepads (including communication functions), electronic dictionaries, calculators, electronic game consoles, word processors, workstations, videophones, anti-theft television monitors, electronic telescopes, POS terminals, medical equipment (such as electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiogram measuring devices, ultrasonic diagnostic equipment, electronic endoscopes), fish finders, various measuring machines, measuring instruments (such as measuring instruments for vehicles, aircraft, and ships), flight simulators, etc.

[0178] (Mobile object)

[0179] Figure 29 1 is a perspective view schematically showing a vehicle as a mobile body equipped with a physical quantity sensor according to an embodiment of the present invention. The physical quantity sensor 100 according to the embodiment is mounted on the vehicle 1500. For example, Figure 29As shown, a physical quantity sensor 100 is built into a mobile vehicle 1500, and an electronic control unit 1510 is mounted on the vehicle body as a control unit for controlling the tires and other components. Physical quantity sensor 100 is also widely used in electronic control units (ECUs) such as keyless entry systems, engine immobilizer systems, car navigation systems, car air conditioners, anti-lock braking systems (ABS), airbags, tire pressure monitoring systems (TPMS), engine controllers, battery monitors for hybrid and electric vehicles, and vehicle posture control systems.

Claims

1. A physical quantity sensor, characterized in that: When the three mutually orthogonal axes are set as X-axis, Y-axis and Z-axis, The physical quantity sensor comprises: support base plate; a movable body, which faces the support substrate in the Z-axis direction along the Z-axis, includes a first mass unit, a second mass unit, and a connecting portion connecting the first mass unit and the second mass unit, and is arranged to be swingable relative to the support substrate about a rotation axis along the Y-axis; a first fixed electrode provided in a first region of the support substrate that is opposite to and overlaps with the first mass portion; a second fixed electrode provided in a second region of the support substrate that is opposite to and overlaps with the second mass portion; a first protrusion, disposed in the first region; as well as A second protrusion is provided in the second area, In the X-axis direction along the X-axis, When the distance from the connection position between the coupling portion and the first mass portion to the end of the first mass portion on the opposite side of the rotation axis is set to L, and the distance from the first protrusion to the end of the first mass portion on the opposite side of the rotation axis and the distance from the second protrusion to the end of the second mass portion on the opposite side of the rotation axis are respectively set to L1, 0.18L≤L1≤0.88L is satisfied. The first protrusion and the second protrusion are arranged line-symmetrically with respect to a center line bisecting the movable body in the Y-axis direction along the Y-axis, and are arranged at line-symmetrical positions with respect to a rotation center of the rotation axis.

2. The physical quantity sensor according to claim 1, wherein The movable body includes a support portion disposed between the first mass portion and the second mass portion, and a beam portion connecting the support portion and the connection portion.

3. The physical quantity sensor according to claim 1 or 2, characterized in that The support base is provided with a support column for supporting the movable body at a distance therefrom in the Z-axis direction. The support portion is fixed to the support column.

4. The physical quantity sensor according to claim 1 or 2, characterized in that The first mass portion and the second mass portion are provided with a plurality of openings penetrating in the Z-axis direction in a lattice pattern. In a plan view in the Z-axis direction, the first protrusion and the second protrusion are respectively arranged on the inner side of the four openings arranged in two rows and two columns.

5. The physical quantity sensor according to claim 1 or 2, characterized in that When viewed from above in the Z-axis direction, The first mass unit and the second mass unit are provided with slits along the connecting portion on the rotation axis side. The connecting portion is extended by the slit.

6. A composite sensor, characterized in that: The composite sensor has: The physical quantity sensor according to any one of claims 1 to 5; and Angular velocity sensor.

7. An inertial measurement unit, characterized in that The inertial measurement unit comprises: The physical quantity sensor according to any one of claims 1 to 5; angular velocity sensor; and The control unit controls the physical quantity sensor and the angular velocity sensor.

8. A portable electronic device, characterized in that: The portable electronic device comprises: The physical quantity sensor according to any one of claims 1 to 5; a housing housing the physical quantity sensor; a processing unit housed in the housing and configured to process output data output from the physical quantity sensor; a display portion housed in the housing; as well as The light-transmitting cover blocks the opening of the housing.

9. An electronic device, characterized in that: The electronic device comprises: The physical quantity sensor according to any one of claims 1 to 5; and The control unit performs control based on a detection signal output from the physical quantity sensor.

10. A mobile object, characterized in that: The mobile body comprises: The physical quantity sensor according to any one of claims 1 to 5; and The control unit performs control based on a detection signal output from the physical quantity sensor.

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