Gyro sensor, electronic device, and mobile object

Abstract

To provide a precise gyro sensor, an electronic apparatus, and a mobile body.SOLUTION: The gyro sensor includes: a substrate 2; a fixed unit 48 fixed to the substrate 2; a driven unit 40, driven along an X-plane parallel to a main surface 23 of the substrate 2; a mass unit 41 connected to the driven unit 40, the driven unit being displaced along a first axis; a detection unit 45 connected to the mass unit 41, the detection unit being rotatable around a Z-axis intersecting with the X-axis and being displacable along the Z-axis by a Coriolis force that acts on a rotational movement horizontal to the substrate 2, and an elastic unit 47, connecting the detection unit 45 and the fixed unit 48 to each other. The fixed unit 48 is arranged between the center of gravity G of the detection unit 45 and the mass unit 41 in planer view.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a gyro sensor, an electronic device, and a moving object. [Background technology]

[0002] 2. Description of the Related Art In recent years, gyroscopes or gyro sensors using gyro sensor elements manufactured using silicon MEMS (Micro Electro Mechanical System) technology have been developed. As such a gyroscope, for example, Patent Document 1 discloses a gyroscope in which a driving actuator located at the center drives two mass elements connected to both sides of the driving actuator to rotate, thereby detecting the angular velocity around an axis in the driving direction of the driving actuator. In this gyroscope, one end of the mass element is connected to the driving actuator, and the other end is connected to a fixed part fixed to a substrate via an elastic spring. The elastic spring allows in-plane rotation around the fixed part and also functions as a torsion spring. Therefore, when the mass element is subjected to in-plane rotation by the driving actuator and receives rotation around an axis in the driving direction of the driving actuator, a Coriolis force is applied to the mass element according to the speed and displacement of the in-plane rotation. This Coriolis force acts in a twisting direction on the elastic spring, displacing the two mass elements in opposite phases, and the displacement amount is differentially detected by a detection electrode arranged on the substrate, thereby making it possible to detect the angular velocity around the axis in the driving direction of the driving actuator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-211386 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the gyro sensor that applies rotational drive vibration among the gyro sensors described in Patent Document 1, the elastic spring extending from the fixed portion extends toward the drive actuator, so the rotation radius of the mass element is short. As a result, the amount of displacement of the in-plane rotational motion of the mass element caused by the drive of the drive actuator is small, and even if the mass element receives rotational motion around an axis in the drive direction of the drive actuator, the amount of displacement of the mass element toward the detection electrode is small, resulting in a problem of reduced detection sensitivity. [Means for solving the problem]

[0005] The gyro sensor comprises a substrate, a fixed portion fixed to the substrate, a mass portion displaced along a first axis parallel to a main surface of the substrate, a drive portion driving the mass portion along the first axis, a detection portion connected to the mass portion, rotatable around a second axis intersecting the first axis, and displaceable along the second axis by a Coriolis force acting on the substrate in a rotational motion horizontal to the substrate, and an elastic portion connecting the detection portion and the fixed portion, wherein the fixed portion is disposed between the center of gravity of the detection portion and the mass portion in a planar view.

[0006] In the above gyro sensor, it is preferable that the fixed portion is disposed between the elastic portion and the mass portion.

[0007] In the above gyro sensor, it is preferable that a joint extending from the detection portion along a third axis intersecting the first axis and the second axis and joining the elastic portion and the detection portion is positioned between the center of gravity of the detection portion and the mass portion.

[0008] In the above gyro sensor, it is preferable that the detection portion has a groove that is arranged at a position closer to the elastic portion than to an end of the detection portion opposite to the mass portion side.

[0009] In the above gyro sensor, it is preferable that the groove is arranged at a position where the center of the groove in the first axial direction does not overlap with an extension line along the third axis that passes through the center of the joint in the first axial direction.

[0010] The gyro sensor includes a substrate, a mass portion displaceable along a first axis parallel to a main surface of the substrate, a drive portion that drives the mass portion along the first axis, a fixed portion fixed to the substrate, a first detection portion disposed in a first direction along a second axis intersecting the first axis of the fixed portion, connected to the mass portion, rotatable about a third axis intersecting the first axis and the second axis, and displaceable along the third axis due to a Coriolis force acting on a rotational motion horizontal to the substrate, and a second detection portion disposed in a second direction opposite to the first direction of the fixed portion. the second detection unit is arranged in a direction perpendicular to the substrate, connected to the mass unit, rotatable about the third axis, and displaceable in opposite phase to the first detection unit along the third axis due to a Coriolis force acting on the rotational motion horizontal to the substrate; a first elastic unit connecting the first detection unit and the fixed unit; and a second elastic unit connecting the second detection unit and the fixed unit, the fixed unit being arranged, in a planar view, between the mass unit and a virtual line connecting the center of gravity of the first detection unit and the center of gravity of the second detection unit.

[0011] The electronic device is characterized by including the above-mentioned gyro sensor.

[0012] The moving object is characterized by including the above-mentioned gyro sensor. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a plan view showing a schematic configuration of a gyro sensor according to a first embodiment. [Diagram 2] Cross-sectional view taken along line AA in Figure 1. [Diagram 3] An enlarged view of part B in Figure 1. [Figure 4] FIG. 4 is a plan view illustrating the operation of the gyro sensor. [Diagram 5]FIG. 11 is a plan view showing a schematic configuration of a gyro sensor according to a second embodiment. [Figure 6] FIG. 11 is a perspective view showing the configuration of a mobile phone as an electronic device including a gyro sensor according to a third embodiment. [Figure 7] FIG. 13 is a perspective view showing the configuration of an automobile as a moving object equipped with a gyro sensor according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] 1. First embodiment First, a gyro sensor 1 according to a first embodiment will be described with reference to FIGS. 1 to 4. FIG. FIG. 1 is a plan view showing a gyro sensor 1 according to the first embodiment. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. FIG. 3 is an enlarged view of part B in FIG. 1. FIG. 4 is a plan view for explaining the operation of the gyro sensor 1. In FIG. 1, the substrate 2 is illustrated in a schematic manner, and the cover part 3 is omitted. In addition, in each of the above figures, some components are omitted for convenience of explanation. For example, wiring for extracting electric signals and a protective structure called a stopper for buffering excessive vibration and impact. In each of the figures, the dimensional ratios of each component are different from the actual ratios for ease of understanding. In addition, the X-axis, Y-axis, and Z-axis in the figures are mutually orthogonal coordinate axes, the direction along the X-axis is the "X direction", the direction along the Y-axis is the "Y direction", and the direction along the Z-axis is the "Z direction", and the direction of the arrow is the positive direction. In addition, in this embodiment, the first axis is the X-axis, the second axis is the Z-axis, and the third axis is the Y-axis.

[0015] The gyro sensor 1 shown in Fig. 1 is an angular velocity sensor capable of detecting an angular velocity around the X-axis. As shown in Fig. 2, the gyro sensor 1 has an element unit 4 and a package 10 that houses the element unit 4.

[0016] The package 10 has a substrate 2 supporting an element portion 4 and a lid portion 3 joined to the substrate 2, and a space S for housing the element portion 4 is formed between the substrate 2 and the lid portion 3.

[0017] The substrate 2 and the lid portion 3 each have a plate shape and are disposed along the XY plane, which is a plane including the X-axis and the Y-axis.

[0018] The substrate 2 is provided with a recess 21 that opens upward toward the element section 4. A protruding portion 24 protruding from a bottom surface 22 of the recess 21 is provided in the center of the recess 21. A fixing portion 48, which is a part of the element section 4 and will be described later, is fixed to a main surface 23 that is the upper surface of the protruding portion 24. The recess 21 is also provided with a plurality of protruding portions (not shown) protruding from the bottom surface 22, to which a fixing portion 43 and a part of the element section 4, which will be described later, and fixed driving portions 27 and 28, are fixed. A fixed detection portion 25 that generates electrostatic capacitance between the bottom surface 22 of the recess 21 and a detection portion 45, which is a part of the element section 4 and will be described later, is provided on the bottom surface 22 of the recess 21.

[0019] The lid portion 3 is provided with a recess 31 that opens downward toward the substrate 2. The lid portion 3 is provided on the substrate 2 so as to cover the element portion 4 without contacting it, and a lower surface 33 excluding the recess 31 is joined to the main surface 23 surrounding the recess 21 of the substrate 2.

[0020] The space S is an airtight space formed by the recess 21 and the recess 31, and is in a reduced pressure state, for example, 1×10 +2 Pa~1×10 -2 This makes it possible to improve the detection sensitivity of the angular velocity.

[0021] The constituent material of the substrate 2 is not particularly limited, but it is preferable to use a material having insulating properties. Specifically, it is preferable to use a high-resistance silicon material or glass material. For example, it is preferable to use a glass material containing a certain amount of alkali metal ions, for example, borosilicate glass such as Pyrex (registered trademark) glass. In this way, when the element section 4 is mainly made of silicon, the substrate 2 and the element section 4 can be anodically bonded. By anodically bonding, the element section 4 can be firmly fixed to the substrate 2. Therefore, it is possible to provide a highly reliable gyro sensor 1 that is unlikely to peel off. Alternatively, a quartz substrate, a crystal substrate, or an SOI (Silicon on Insulator) substrate may be used.

[0022] The material of the cover 3 is not particularly limited, and may be the same as the material of the substrate 2 described above.

[0023] The method of bonding the substrate 2 and the lid 3 varies depending on the materials of the substrate 2 and the lid 3, and is not particularly limited. For example, a bonding method using a bonding material such as an adhesive, a wax material, or a glass frit material, a solid bonding method such as direct bonding or anodic bonding can be used. In particular, with a glass frit material, the glass frit material flows even on an uneven surface, and an airtight space can be satisfactorily secured. In particular, in the case of the gyro sensor 1, the airtight space needs to be maintained in a reduced pressure state, and therefore a glass frit material is preferably used.

[0024] 1, the element unit 4 has a fixed unit 48 fixed to the substrate 2, a mass unit 41 displaceable in the X direction parallel to the main surface 23 of the substrate 2, a drive unit 40 that drives the mass unit 41 in the X direction, a detection unit 45 that is connected to the mass unit 41, rotatable around the Z axis, and displaceable in the Z direction by Coriolis force acting on the rotational motion horizontal to the substrate 2, and an elastic unit 47 that connects the detection unit 45 and the fixed unit 48. In this embodiment, the fixed unit 48, the detection unit 45, and the elastic unit 47 each form a pair and are disposed symmetrically on both sides of the mass unit 41, that is, disposed line-symmetrically with respect to the Y axis.

[0025] Mass unit 41 has a rectangular shape with its long sides extending in the X direction, and has an opening 49a in the center. In opening 49a, a plurality of drive units 40 connected to mass unit 41 and a plurality of fixed drive units 27, 28 fixed to substrate 2 are arranged.

[0026] The drive unit 40 and the fixed drive units 27, 28 each have a plurality of beams extending in the X direction and are arranged in a comb-like shape. The fixed drive unit 27 is arranged on the positive side of the drive unit 40 in the X direction, and the beams of the drive unit 40 and the fixed drive unit 27 are arranged to mesh with each other. The fixed drive unit 28 is arranged on the negative side of the drive unit 40 in the X direction, and the beams of the drive unit 40 and the fixed drive unit 28 are arranged to mesh with each other.

[0027] The mass portion 41 is connected to four fixed portions 43 fixed to the substrate 2 via four drive springs 42 each having a folded-back shape at both ends in the X direction. The drive springs 42 are formed so as to bend or deform in the X direction due to an external force applied from the X direction. Therefore, the drive springs 42 enable the mass portion 41 to be displaced in the X direction.

[0028] A coupling spring 44 is provided in the center of the X direction of the mass unit 41, extending in the positive direction of the Y axis from an end opposite the opening 49a on the positive side in the Y direction, and a detection unit 45 is connected to the end of the coupling spring 44 opposite the mass unit 41 side. In addition, a coupling spring 44 is provided in the center of the X direction of the mass unit 41, extending in the negative direction of the Y axis from an end opposite the opening 49a on the negative side in the Y direction, and a detection unit 45 is connected to the end of the coupling spring 44 opposite the mass unit 41 side.

[0029] The detection unit 45 has a rectangular shape that is long in the X direction, and has an opening 49b at the center in the X direction, closer to the mass unit 41 side than the center of gravity G of the detection unit 45. In the opening 49b, a fixed unit 48 fixed to the substrate 2, an elastic unit 47 connected to the fixed unit 48, and a joint unit 46 extending from the elastic unit 47 in the Y direction and jointed to the detection unit 45 are arranged.

[0030] The elastic portion 47 extends in the Y direction from the fixed portion 48 while folding back in the positive and negative directions of the X direction, and is connected to the joint portion 46. The elastic portion 47 is formed so as to bend or deform in the X direction or the Y direction due to an external force applied from the X direction or the Y direction. The structure is resistant to deformation due to an external force applied from the Z direction. Therefore, when the mass portion 41 is displaced in the X direction, the detection portion 45 can rotate or displace horizontally to the substrate 2 around the central axis J, which is the connection point between the elastic portion 47 and the fixed portion 48 as shown in FIG.

[0031] The joint 46 is disposed between the center of gravity G of the detection unit 45 and the mass unit 41, extends in the Y direction from the elastic unit 47, and is joined to the detection unit 45. Therefore, the length from the fixed unit 48 to the detection unit 45 can be increased, the rotation radius of the detection unit 45 from the central axis J can be increased, and the amount of displacement of the in-plane rotational movement of the detection unit 45 accompanying the drive of the drive unit 40 can be increased.

[0032] In addition, the joint 46 is formed to twist around the Y-axis. Therefore, when an angular velocity ωx around the X-axis is applied to the detection unit 45 while the detection unit 45 is rotating in a plane, the Coriolis force acting on the in-plane rotational motion of the detection unit 45 is applied in opposite directions to the positive side in the X direction of the detection unit 45 and the negative side in the X direction of the detection unit 45, respectively, so that the detection unit 45 can be displaced in the Z direction. Specifically, when the positive side of detection unit 45 in the X direction is displaced in the positive direction of the Z axis, the negative side of detection unit 45 in the X direction is displaced in the negative direction of the Z axis. Conversely, when the positive side of detection unit 45 in the X direction is displaced in the negative direction of the Z axis, the negative side of detection unit 45 in the X direction is displaced in the positive direction of the Z axis. Furthermore, detection unit 45 arranged in the positive direction of the Y axis and detection unit 45 arranged in the negative direction of the Y axis are displaced in opposite phases.

[0033] Fixed detection unit 25 is provided at a position facing detection unit 45 on bottom surface 22 of recess 21 of substrate 2, spaced apart from detection unit 45. When angular velocity ωx about the X-axis is applied and detection unit 45 is displaced in the Z direction, the change in the distance to fixed detection unit 25 is detected as a change in capacitance, and the angular velocity ωx about the X-axis can be detected.

[0034] Moreover, the shape of fixed detection unit 25 is a trapezoid having upper and lower bases parallel to the Y direction, and is disposed so that the lower base, which is longer in the Y direction, faces fixed unit 48. By disposing in this manner, detection unit 45 and fixed detection unit 25 always overlap during rotational motion of detection unit 45, so that the opposing area between detection unit 45 and fixed detection unit 25 can be kept constant, and the detection accuracy of angular velocity ωx about the X axis can be maintained.

[0035] The fixed portion 48 is disposed within the opening 49b of the detection portion 45, and is disposed between the center of gravity G of the detection portion 45 and the mass portion 41, and between the elastic portion 47 and the mass portion 41, in a plan view. Therefore, the elastic portion 47 connecting the fixed portion 48 and the detection portion 45 can be disposed in a direction away from the mass portion 41, and the rotation radius of the detection portion 45 from the central axis J can be lengthened. Therefore, when the displacement amount of the in-plane rotational motion of the detection portion 45 caused by the driving of the driving portion 40 becomes large and an angular velocity ωx about the X-axis is applied, the displacement amount of the detection portion 45 in the Z direction becomes large due to the acting Coriolis force, and the detection sensitivity can be improved.

[0036] The detection unit 45 has grooves 50, 51 arranged at a position closer to the elastic unit 47 than the end of the detection unit 45 on the opposite side to the mass unit 41 side. As shown in FIG. 3, the groove 50 is arranged at a position where the center P2 of the groove 50 in the X direction does not overlap with an extension line L along the Y axis passing through the center P1 of the joint 46 in the X direction. Similarly, the groove 51 is arranged at a position where the center of the groove 51 does not overlap with an extension line passing through the center of the joint 46. In this way, by providing the grooves 50, 51 in the detection unit 45, it is possible to reduce an increase in unnecessary vibration components, so-called quadrature signals, which are vibration components different from the driving vibration in the X axis direction caused by the processing error of the elastic unit 47. Generally, the processing error that causes the unnecessary vibration components does not have symmetry with respect to the desired processing shape, so it is preferable to compensate using the grooves 50, 51 that do not have symmetry such as rotational symmetry, line symmetry, or point symmetry with respect to the X axis, Y axis, and Z axis as described above.

[0037] The element portion 4 as described above is formed in one go by patterning, by etching, a conductive silicon substrate doped with impurities such as phosphorus and boron.

[0038] Moreover, examples of materials that can be used for the fixed detection portion 25 include aluminum, gold, platinum, ITO (Indium Tin Oxide), and ZnO (Zinc Oxide).

[0039] Next, the gyro sensor 1 configured as described above can detect the angular velocity ωx about the X-axis in the following manner.

[0040] First, when a drive voltage is applied between the drive unit 40 and the fixed drive units 27, 28 of the gyro sensor 1, an electrostatic attraction whose strength changes periodically is generated between the fixed drive units 27, 28 and the drive unit 40. As a result, as shown in Fig. 4, when the drive unit 40 vibrates in the X direction with the elastic deformation of the drive spring 42 and displaces in the direction of the arrow X1, the two detection units 45 connected to the mass unit 41, which displaces in the direction of the arrow X1 similarly to the drive unit 40, rotate in opposite phases around the Z axis around the contact point between the fixed unit 48 and the elastic unit 47 to which they are connected.

[0041] In the detection unit 45 located on the positive side of the mass unit 41 in the Y direction, the positive side of the X direction of the detection unit 45 is displaced in the direction of the arrow Y1, and the negative side of the X direction of the detection unit 45 is displaced in the direction of the arrow Y2. The displaced detection unit 45 is shown by a dashed line in FIG. 4. Conversely, in the detection unit 45 located on the negative side of the Y direction of the mass unit 41, the negative side of the X direction of the detection unit 45 is displaced in the direction of the arrow Y1, and the positive side of the X direction of the detection unit 45 is displaced in the direction of the arrow Y2. In other words, the detection unit 45 located on the positive side of the Y direction of the mass unit 41 rotates counterclockwise, and the detection unit 45 located on the negative side of the Y direction of the mass unit 41 rotates clockwise. Furthermore, when the drive unit 40 and the mass unit 41 are displaced in the direction opposite to the arrow X1, the detection unit 45 located on the positive side of the mass unit 41 in the Y direction rotates clockwise, and the detection unit 45 located on the negative side of the mass unit 41 in the Y direction rotates counterclockwise.

[0042] When an angular velocity ωx about the X-axis is applied to the gyro sensor 1 while the detection unit 45 is rotating in-plane about the Z-axis in this manner, a Coriolis force acts, and the detection unit 45 is displaced in the Z direction. At this time, the detection unit 45 located on the positive side of the mass unit 41 in the Y direction has the positive X-direction side of the detection unit 45 displaced in the direction of the arrow Z2, and the negative X-direction side of the detection unit 45 displaced in the direction of the arrow Z1. Conversely, the detection unit 45 located on the negative side of the mass unit 41 in the Y direction has the negative X-direction side of the detection unit 45 displaced in the direction of the arrow Z2, and the positive X-direction side of the detection unit 45 displaced in the direction of the arrow Z1.

[0043] When the drive unit 40 and the mass unit 41 are displaced in the direction opposite to the arrow X1, the detection unit 45 located on the positive side of the Y direction of the mass unit 41 has the positive X direction side of the detection unit 45 displaced in the direction of the arrow Z1, and the negative X direction side of the detection unit 45 displaced in the direction of the arrow Z2. Conversely, the detection unit 45 located on the negative side of the Y direction of the mass unit 41 has the negative X direction side of the detection unit 45 displaced in the direction of the arrow Z1, and the positive X direction side of the detection unit 45 displaced in the direction of the arrow Z2.

[0044] By displacing the detection unit 45 in the Z direction in this manner, the distance between the detection unit 45 and the fixed detection unit 25 changes. This change in distance causes a change in the capacitance between the detection unit 45 and the fixed detection unit 25. Then, based on the amount of change in capacitance, the angular velocity ωx about the X axis applied to the gyro sensor 1 can be detected.

[0045] As described above, the gyro sensor 1 of the present embodiment is configured such that the fixed portion 48 is disposed at a position close to the mass portion 41, and the elastic portion 47 connecting the fixed portion 48 and the detection portion 45 is disposed in a direction away from the mass portion 41, thereby making it possible to lengthen the rotation radius of the detection portion 45 from the central axis J. Therefore, when the displacement amount of the in-plane rotational motion of the detection portion 45 caused by the driving of the driving portion 40 increases and an angular velocity ωx about the X-axis is applied, the displacement amount of the detection portion 45 in the Z direction increases due to the acting Coriolis force, so that the detection sensitivity of the gyro sensor 1 can be improved. Therefore, it is possible to obtain a gyro sensor 1 having high detection sensitivity. In addition, the elastic portion 47 connecting the fixed portion 48 and the detection portion 45 is disposed in a direction away from the mass portion 41, thereby dispersing the stress concentration applied to the elastic portion 47 and its periphery. This makes it possible to prevent a decrease in reliability due to factors such as fatigue failure, etc. As a result, it is possible to provide a gyro sensor 1 that has high performance and high reliability.

[0046] 2. Second embodiment Next, a gyro sensor 1a according to a second embodiment will be described with reference to FIG. FIG. 5 is a plan view showing a schematic configuration of a gyro sensor 1a according to the second embodiment. In FIG. 5, the substrate 2 and the cover 3 are omitted. In FIG. 5, some components are omitted for convenience of explanation, and the dimensional ratios of each component are different from the actual ones for ease of understanding. In addition, the X-axis, Y-axis, and Z-axis in the figure are coordinate axes perpendicular to each other, and the direction along the X-axis is the "X direction", the direction along the Y-axis is the "Y direction", and the direction along the Z-axis is the "Z direction", and the directions of the arrows are positive directions. In this embodiment, the first axis is the X-axis, the second axis is the Y-axis, and the third axis is the Z-axis, and the first direction is the positive direction of the Y-axis, and the second direction is the negative direction of the Y-axis.

[0047] The gyro sensor 1a of this embodiment is an angular velocity sensor capable of detecting an angular velocity around the X-axis, similar to the gyro sensor 1 of the first embodiment. The gyro sensor 1a has a different configuration of an element unit 4a compared to the gyro sensor 1 of the first embodiment, and has four detection units 85a, 85b around a mass unit 81.

[0048] As shown in FIG. 5, the element unit 4a of this embodiment has a fixed unit 88 fixed to the substrate 2, a mass unit 81 displaceable in the X direction parallel to the main surface 23 of the substrate 2, a plurality of drive units 80 that drive the mass unit 81 in the X direction, a first detection unit 85a arranged in the positive direction of the Y axis as a first direction of the fixed unit 88, connected to the mass unit 81, rotatable around the Z axis, and displaceable in the Z direction by the Coriolis force acting on the rotational motion horizontal to the substrate 2, a second detection unit 85b arranged in the negative direction of the Y axis as a second direction of the fixed unit 88, connected to the mass unit 81, rotatable around the Z axis, and displaceable in the Z direction by the Coriolis force acting on the rotational motion horizontal to the substrate 2, a first elastic unit 87a connecting the first detection unit 85a and the fixed unit 88, and a second elastic unit 87b connecting the second detection unit 85b and the fixed unit 88. In this embodiment, the fixed portion 88, the first detection portion 85a, the second detection portion 85b, the first elastic portion 87a, the second elastic portion 87b, and the two driving portions 80 are each a pair and are arranged symmetrically on both sides of the mass portion 81, that is, arranged linearly symmetrically with respect to the Y axis.

[0049] The mass portion 81 has a rectangular prism portion 81a with its long side in the Y direction, and rectangular connection portions 81b with its long side in the X direction at both ends in the Y direction of the prism portion 81a. The prism portion 81a is provided with a drive spring 82 at both ends in the X direction at the center in the Y direction, which extends in the X direction while folding back in the positive and negative directions of the X direction, and is connected to a fixed portion 88. The prism portion 81a is also provided with four drive portions 80 having comb-like beam portions extending in the X direction at both ends in the X direction. At both ends in the X direction of the connection portion 81b, which is arranged on the positive side of the Y direction of the rectangular column portion 81a, a coupling spring 84 extending toward the negative side of the Y direction and connected to the first detection portion 85a is provided, and at both ends in the X direction of the connection portion 81b, which is arranged on the negative side of the Y direction of the rectangular column portion 81a, a coupling spring 84 extending toward the positive side of the Y direction and connected to the second detection portion 85b is provided.

[0050] The connecting portion 81b is provided with a notch 81c that opens on the side opposite to the rectangular column portion 81a in the Y direction, the fixing portion 83 is disposed in the center of the notch 81c in the X direction, and elastic springs 89 that connect the connecting portion 81b and the fixing portion 83 are provided on both ends of the notch 81c in the X direction. The driving spring 82 and the elastic spring 89 are formed so as to bend or deform in the X direction due to an external force applied from the X direction. Therefore, the mass portion 81 is displaceable in the X direction.

[0051] Four fixed driving units 29 are arranged on the positive and negative sides of the rectangular column portion 81a in the X direction, each of which has a plurality of beam portions extending in the X direction in a comb-like shape and is arranged so as to mesh with the plurality of beam portions of the driving unit 80. A part of the fixed driving unit 29 is fixed to the substrate 2. When a driving voltage is applied between the driving unit 80 and the fixed driving unit 29, an electrostatic attractive force whose strength changes periodically is generated between the fixed driving unit 29 and the driving unit 80, which causes the driving unit 80 to vibrate in the X direction accompanied by elastic deformation of the driving spring 82, and the first detection unit 85a and the second detection unit 85b connected to the mass unit 81, which is displaced in the same manner as the driving unit 80, perform an in-plane rotational motion.

[0052] The fixed portion 88 to which the drive spring 82 is connected has a first elastic portion 87a on the positive side of the Y direction and a joint portion 86a extending from the first elastic portion 87a in the Y direction and joining to the first detection portion 85a, and has a second elastic portion 87b on the negative side of the Y direction and a joint portion 86b extending from the second elastic portion 87b in the Y direction and joining to the second detection portion 85b.

[0053] The first elastic portion 87a and the second elastic portion 87b extend in the Y direction while folding back from the fixed portion 88 in the positive and negative directions of the X direction, respectively, and are connected to the joint portions 86a and 86b, respectively. The first elastic portion 87a and the second elastic portion 87b are formed so as to bend or deform in the X direction or the Y direction due to an external force applied from the X direction or the Y direction. Note that they are structured so as not to be easily deformed by an external force applied from the Z direction. Therefore, when the mass portion 81 is displaced in the X direction, the first detection portion 85a can rotate or be displaced horizontally with respect to the substrate 2 about the connection point between the first elastic portion 87a and the fixed portion 88 as a central axis, and the second detection portion 85b can rotate or be displaced horizontally with respect to the substrate 2 about the connection point between the second elastic portion 87b and the fixed portion 88 as a central axis. In addition, when an external force in the X direction is applied, when the first detection unit 85a rotates clockwise, the second detection unit 85b rotates counterclockwise, and when the first detection unit 85a rotates counterclockwise, the second detection unit 85b rotates clockwise. In addition, the first detection unit 85a and the second detection unit 85b arranged on the positive and negative sides in the Y direction rotate in opposite phases.

[0054] The joints 86a and 86b are formed to twist around the Y axis. Therefore, when the first detection unit 85a and the second detection unit 85b are rotating in a plane, if an angular velocity ωx around the X axis is applied, a Coriolis force in the opposite direction is applied to the first detection unit 85a and the second detection unit 85b, and the first detection unit 85a and the second detection unit 85b can be displaced in the Z direction. Specifically, when the first detection unit 85a is displaced in the positive direction of the Z axis, the second detection unit 85b is displaced in the negative direction of the Z axis. Conversely, when the first detection unit 85a is displaced in the negative direction of the Z axis, the second detection unit 85b is displaced in the positive direction of the Z axis. In addition, the first detection unit 85a and the second detection unit 85b arranged on the positive side and the negative side of the Y direction are displaced in opposite phases.

[0055] A first fixed detection unit 25a is provided on the bottom surface 22 of the recess 21 of the substrate 2 at a position facing the first detection unit 85a and spaced apart from the first detection unit 85a, and a second fixed detection unit 25b is provided on the bottom surface 22 of the recess 21 of the substrate 2 and spaced apart from the second detection unit 85b, so that when an angular velocity ωx about the X axis is applied and the first detection unit 85a and the second detection unit 85b are displaced in the Z direction, the change in the distance between the first fixed detection unit 25a and the second fixed detection unit 25b is detected as a change in capacitance, and the angular velocity ωx about the X axis can be detected.

[0056] Since the fixed portion 88 is disposed between the mass portion 81 and a virtual straight line La connecting the center of gravity Ga of the first detection portion 85a and the center of gravity Gb of the second detection portion 85b in a plan view, the rotation radius of the first detection portion 85a and the second detection portion 85b can be made longer than when the fixed portion 88 is disposed on the opposite side of the mass portion 81 from the virtual straight line La. Therefore, when the displacement amount of the in-plane rotational motion of the first detection portion 85a and the second detection portion 85b caused by the drive of the drive portion 80 becomes large and an angular velocity ωx about the X-axis is applied, the displacement amount of the first detection portion 85a and the second detection portion 85b in the Z direction becomes large due to the acting Coriolis force, and the detection sensitivity can be improved.

[0057] The first detection section 85a and the second detection section 85b are provided with grooves 90, 91, 92, and 93 arranged at positions close to the joints 86a and 86b. In this way, by providing the grooves 90, 91, 92, and 93 in the first detection section 85a and the second detection section 85b, it is possible to reduce an increase in unnecessary vibration components, so-called quadrature signals, which are vibration components different from the driving vibration in the X-axis direction due to the processing error of the first elastic section 87a and the second elastic section 87b. As described above, since the processing error that causes the unnecessary vibration components does not have symmetry with respect to the desired processing shape, it is preferable to compensate using the grooves 90, 91, 92, and 93 that do not have symmetry such as rotational symmetry, line symmetry, or point symmetry with respect to the X-axis, Y-axis, and Z-axis as described above.

[0058] As described above, in the gyro sensor 1a of this embodiment, the fixing portion 88 is disposed between the virtual straight line La connecting the center of gravity Ga of the first detection portion 85a and the center of gravity Gb of the second detection portion 85b, and the mass portion 81, so that the rotation radius of the first detection portion 85a and the second detection portion 85b can be increased. Therefore, when the displacement amount of the in-plane rotational motion of the first detection portion 85a and the second detection portion 85b caused by the driving of the driving portion 80 increases and an angular velocity ωx about the X-axis is applied, the displacement amount of the first detection portion 85a and the second detection portion 85b in the Z direction increases due to the acting Coriolis force, so that the detection sensitivity can be increased. Therefore, the gyro sensor 1a having high detection sensitivity can be obtained. In addition, by increasing the rotation radius of the first detection portion 85a and the second detection portion 85b, the stress concentration applied to the joints 86a, 86b and their surroundings can be dispersed. Therefore, it is possible to prevent a decrease in reliability due to factors such as fatigue failure. Therefore, it is possible to provide a gyro sensor 1a with high performance and high reliability.

[0059] 3. Third embodiment Next, a mobile phone 1200 will be described as an example of an electronic device including the gyro sensor 1, 1a according to the third embodiment. In the following description, a configuration to which the gyro sensor 1 is applied will be described as an example. FIG. 6 is a perspective view showing the configuration of a mobile phone 1200 equipped with the gyro sensor 1. As shown in FIG. As shown in FIG. 6, a mobile phone 1200 includes a plurality of operation buttons 1202, an earpiece 1204, and a mouthpiece 1206, and a display unit 1201 is disposed between the operation buttons 1202 and the earpiece 1204. Such a mobile phone 1200 has a built-in gyro sensor 1 .

[0060] Such electronic devices include the above-mentioned gyro sensor 1, and therefore the effects described in the above embodiment are reflected, resulting in excellent performance. In addition to the mobile phone 1200, examples of electronic devices equipped with the above-mentioned gyro sensor 1, 1a include, for example, inkjet printers and other inkjet discharge devices, laptop and mobile personal computers, televisions, digital still cameras, video cameras, video tape recorders, various navigation devices, pagers, electronic organizers including those with communication functions, electronic dictionaries, calculators, electronic game devices, word processors, workstations, videophones, security television monitors, electronic binoculars, POS terminals, fish finders, various measuring devices, gauges, flight simulators, and medical devices such as electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiogram measuring devices, ultrasonic diagnostic devices, and electronic endoscopes. In any case, since these electronic devices are equipped with the above-mentioned gyro sensor 1, 1a, the effects described in the above embodiment are reflected and the performance is excellent.

[0061] 4. Fourth embodiment Next, an automobile 1500 will be described as an example of a moving body including the gyro sensor 1, 1a according to the fourth embodiment. In the following description, a configuration to which the gyro sensor 1 is applied will be described as an example. FIG. 7 is a perspective view showing an automobile 1500 equipped with the gyro sensor 1. As shown in FIG. As shown in FIG. 7, an automobile 1500 uses the gyro sensor 1 as an attitude detection sensor for, for example, an on-board navigation device, attitude control device, or the like. According to this, the automobile 1500 is equipped with the above-mentioned gyro sensor 1, and therefore the effects described in the above embodiment are reflected, and the performance is excellent.

[0062] The above-mentioned gyro sensors 1, 1a can be suitably used as attitude detection sensors for moving bodies including not only the automobile 1500 but also self-propelled robots, self-propelled conveying equipment, trains, ships, airplanes, and artificial satellites, and in any case, the effects described in the above embodiments are reflected, making it possible to provide a moving body with excellent performance.

[0063] The following describes the contents derived from the embodiment.

[0064] The gyro sensor comprises a substrate, a fixed portion fixed to the substrate, a mass portion displaced along a first axis parallel to a main surface of the substrate, a drive portion driving the mass portion along the first axis, a detection portion connected to the mass portion, rotatable around a second axis intersecting the first axis, and displaceable along the second axis by a Coriolis force acting on the substrate in a rotational motion horizontal to the substrate, and an elastic portion connecting the detection portion and the fixed portion, wherein the fixed portion is disposed between the center of gravity of the detection portion and the mass portion in a planar view.

[0065] According to this configuration, since the fixed part is disposed between the center of gravity of the detection part and the mass part, the elastic part connecting the fixed part and the detection part can be disposed in a direction away from the mass part, and the rotation radius of the detection part can be increased. Therefore, the amount of displacement of the in-plane rotational motion of the detection part caused by the driving of the driving part becomes large, and when an external force about the first axis is applied, the amount of displacement of the detection part along the second axis becomes large due to the acting Coriolis force, and the detection sensitivity can be improved.

[0066] In the above gyro sensor, it is preferable that the fixed portion is disposed between the elastic portion and the mass portion.

[0067] According to this configuration, since the fixed portion is disposed between the elastic portion and the mass portion, the fixed portion can be brought closer to the mass portion, and the elastic portion can be disposed on the opposite side of the fixed portion from the mass portion in a direction away from the mass portion, thereby making it possible to increase the rotation radius of the detection portion and to increase the amount of displacement of the in-plane rotational movement of the detection portion caused by the drive portion being driven.

[0068] In the above gyro sensor, it is preferable that a joint extending from the detection portion along a third axis intersecting the first axis and the second axis and joining the elastic portion and the detection portion is positioned between the center of gravity of the detection portion and the mass portion.

[0069] According to this configuration, since the joint that joins the elastic part and the detection part is disposed between the center of gravity of the detection part and the mass part, it is possible to increase the length to the detection part where the fixed part and the joint are joined, and therefore it is possible to increase the rotation radius of the detection part and to increase the amount of displacement of the in-plane rotational movement of the detection part caused by the drive part being driven.

[0070] In the above gyro sensor, it is preferable that the detection portion has a groove that is arranged at a position closer to the elastic portion than to an end of the detection portion opposite to the mass portion side.

[0071] According to this configuration, the groove is arranged at a position close to the elastic portion of the detection unit, so that it is possible to reduce the increase in unnecessary vibration components, so-called quadrature signals, which are vibration components other than the driving vibration along the first axis, that are caused by processing errors in the elastic portion.

[0072] In the above gyro sensor, it is preferable that the groove is arranged at a position where the center of the groove in the first axial direction does not overlap with an extension line along the third axis that passes through the center of the joint in the first axial direction.

[0073] According to this configuration, since the detection part rotates around the second axis, by positioning the groove at a position that does not overlap with the extension line of the joint, it is possible to reduce the increase in unnecessary vibration components, which are vibration components other than the rotational vibration around the second axis, i.e., the so-called quadrature signal.

[0074] The gyro sensor includes a substrate, a mass portion displaceable along a first axis parallel to a main surface of the substrate, a drive portion that drives the mass portion along the first axis, a fixed portion fixed to the substrate, a first detection portion disposed in a first direction along a second axis intersecting the first axis of the fixed portion, connected to the mass portion, rotatable about a third axis intersecting the first axis and the second axis, and displaceable along the third axis due to a Coriolis force acting on a rotational motion horizontal to the substrate, and a second detection portion disposed in a second direction opposite to the first direction of the fixed portion. the second detection unit is arranged in a direction perpendicular to the substrate, connected to the mass unit, rotatable about the third axis, and displaceable in opposite phase to the first detection unit along the third axis due to a Coriolis force acting on the rotational motion horizontal to the substrate; a first elastic unit connecting the first detection unit and the fixed unit; and a second elastic unit connecting the second detection unit and the fixed unit, the fixed unit being arranged, in a planar view, between the mass unit and a virtual line connecting the center of gravity of the first detection unit and the center of gravity of the second detection unit.

[0075] According to this configuration, since the fixed portion is disposed between the mass portion and an imaginary line connecting the center of gravity of the first detection portion and the center of gravity of the second detection portion, the rotation radius of the first detection portion and the second detection portion can be made longer than when the fixed portion is disposed on the opposite side of the imaginary line from the mass portion. Therefore, the amount of displacement of the in-plane rotational motion of the first detection portion and the second detection portion caused by the drive portion being driven becomes large, and when an external force about the first axis is applied, the amount of displacement of the first detection portion and the second detection portion along the second axis becomes large due to the acting Coriolis force, thereby improving the detection sensitivity.

[0076] The electronic device is characterized by including the above-mentioned gyro sensor.

[0077] According to this configuration, since the gyro sensor has high sensitivity and high accuracy, a high-performance electronic device can be provided.

[0078] The moving object is characterized by including the above-mentioned gyro sensor.

[0079] According to this configuration, since the gyro sensor has high sensitivity and high accuracy, a high-performance moving body can be provided. [Explanation of symbols]

[0080] 1,1a...gyro sensor, 2...substrate, 3...lid portion, 4...element portion, 23...main surface, 25...fixed detection portion, 27,28...fixed drive portion, 40...drive portion, 41...mass portion, 42...drive spring, 43...fixed portion, 44...coupling spring, 45...detection portion, 46...joint portion, 47...elastic portion, 48...fixed portion, 50,51...groove, 1200...mobile phone as electronic device, 1500...automobile as moving object, G...center of gravity, J...central axis, L...extension line, P1,P2...center.

Claims

1. When three mutually perpendicular axes are defined as the X-axis, the Y-axis, and the Z-axis, A substrate; an element unit supported on an upper surface of the substrate located on the positive side of the Z axis and detecting an angular velocity based on a change in electrostatic capacitance; Including, The element portion is a mass portion disposed at a distance from the upper surface of the substrate and displaceable in an X-axis direction along the X-axis; A drive unit that drives the mass unit in the X-axis direction; A first fixing portion fixed to the upper surface of the substrate; A second fixing portion fixed to the upper surface of the substrate; a first detection unit connected to the mass unit, rotatable around the Z axis, and displaceable in a Z axis direction along the Z axis; a second detection unit connected to the mass unit, rotatable around the Z axis, and displaceable in the Z axis direction; a first elastic portion connecting the first detection portion and the first fixed portion; a second elastic portion connecting the second detection portion and the second fixed portion; a first fixed detection unit disposed opposite to and spaced apart from the first detection unit; a second fixed detection unit disposed opposite to and spaced apart from the second detection unit; Including, The mass portion is disposed between the first detection portion and the second detection portion in a plan view from the Z axis direction. Gyro sensor.

2. In claim 1, The element portion is a third fixing portion fixed to the upper surface of the substrate and disposed on the positive side in the X-axis direction; a fourth fixing portion fixed to the upper surface of the substrate and disposed on the negative side in the X-axis direction; a third elastic portion connecting an end portion of the mass portion on the positive side in the X-axis direction and the third fixed portion; a fourth elastic portion connecting an end portion of the mass portion on a negative side in the X-axis direction and the fourth fixed portion; Including, Gyro sensor.

3. In claim 1 or claim 2, The first detection unit and the second detection unit are displaced in opposite phases along a plane including the X-axis and the Y-axis. Gyro sensor.

4. In any one of claims 1 to 3, The first elastic portion includes a fold. The second elastic portion includes a fold. Gyro sensor.

5. In claim 4, The first elastic portion includes folds on the positive and negative sides in the X-axis direction, The second elastic portion includes folds on the positive and negative sides in the X-axis direction. Gyro sensor.

6. In any one of claims 1 to 5, The first detection unit is disposed on a positive side in a Y-axis direction along the Y-axis, The second detection unit is disposed on the negative side in the Y-axis direction. Gyro sensor.

7. In any one of claims 1 to 6, a first joint portion connecting the first detection portion and the first elastic portion; a second joint portion connecting the second detection portion and the second elastic portion; Including, Gyro sensor.

8. In claim 7, A first groove is provided on a connection side of the first detection portion with the first joint portion. Gyro sensor.

9. In claim 7 or claim 8, A second groove is provided on a connection side of the second detection portion with the second joint portion. Gyro sensor.

10. In any one of claims 1 to 9, a first connecting spring that connects the mass portion and the first detection portion and extends along the Y axis; a second coupling spring that connects the mass portion and the second detection portion and extends along the Y axis; Including, Gyro sensor.

11. In any one of claims 1 to 10, the first fixed detection unit and the second fixed detection unit are disposed on the upper surface of the substrate, Gyro sensor.

12. In any one of claims 1 to 11, the first fixed portion is disposed between the center of gravity of the first detection portion and the mass portion in a plan view, and the second fixed portion is disposed between the center of gravity of the second detection portion and the mass portion in a plan view. Gyro sensor.

13. The gyro sensor according to any one of claims 1 to 12 is provided. electronic equipment.

14. The gyro sensor according to any one of claims 1 to 12 is provided. Mobile body.

Images