Method for adjusting the position of an inertial sensor and a resonator.

Abstract

To provide an inertial sensor capable of reducing the fluctuation of the gap between a resonator and multiple electrodes on a mounting board after joining the resonator to the mounting board, and an adjustment method thereof.SOLUTION: A resonator 2 includes: a curved surface 21 having a circular 3D surface; and a connection portion 22 extending from the curved surface 21. A mounting board 3 includes: multiple electrodes 53 surrounding the resonator 2 at a distance from each other; and an actuator 52 placed immediately below the connection portion 22. Defining one direction and the direction perpendicular thereto on the plane of the mounting board 3 as x-direction and y-direction, the actuator 52 is capable of being displaced in at least two directions, the x-direction and the y-direction to move the resonator 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to an inertial sensor equipped with a resonator having a three-dimensional curved surface shape, and a method for adjusting the position of the resonator after it has been bonded to a mounting substrate. [Background technology]

[0002] In recent years, the development of autonomous driving systems for vehicles has progressed, and these types of systems require highly accurate self-position estimation technology. For example, development of self-position estimation systems equipped with GNSS and IMU is underway for so-called Level 3 autonomous driving. GNSS is an abbreviation for Global Navigation Satellite System. IMU is an abbreviation for Inertial Measurement Unit, and is, for example, a 6-axis inertial force sensor composed of a 3-axis gyroscope and a 3-axis accelerometer. In the future, to realize so-called Level 4 or higher autonomous driving, an IMU with even higher accuracy than the current one will be required.

[0003] The BRG is considered a promising gyro sensor for realizing such high-precision IMUs, and it consists of a resonator with a roughly hemispherical three-dimensional curved surface that vibrates in wineglass mode, mounted on a circuit board. BRG is an abbreviation for Bird-bath Resonator Gyroscope. This resonator has a Q value of 10, which represents the state of vibration. 6 As this is achieved, higher accuracy than conventional methods can be expected. An example of a method for manufacturing an inertial sensor using this type of resonator mounted on a substrate is the one described in Patent Document 1. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] U.S. Patent No. 10612925 [Overview of the project] [Problems that the invention aims to solve]

[0005] The inertial sensor described in Patent Document 1 is obtained by mounting a resonator having a three-dimensional curved surface on a mounting substrate, then providing a sacrificial layer to temporarily connect the resonator and a plurality of opposing electrodes, and finally etching and separating a portion of the sacrificial layer. As a result, the gap between the resonator and the plurality of opposing electrodes becomes uniform, reducing the variation in capacitance between them and improving sensor accuracy. However, although the gap between the resonator and the plurality of opposing electrodes is uniform at the time of manufacture, this inertial sensor cannot accommodate changes in the gap that occur due to subsequent stress, temperature changes, or aging.

[0006] In view of the above, this disclosure aims to provide an inertial sensor in which a resonator having a three-dimensional curved surface is bonded to a mounting substrate, and which can reduce fluctuations in the gap between the resonator and a plurality of electrodes on the mounting substrate after the bonding of the resonator and the mounting substrate, and a method for adjusting the position of the resonator. [Means for solving the problem]

[0007] An inertial sensor according to one aspect of this disclosure comprises a resonator (2) having a curved surface portion (21) having an annular three-dimensional curved surface and a connecting portion (22) extending from the curved surface portion toward the center of the hemispherical shape formed by the curved surface portion; a mounting substrate (3) having a plurality of electrode portions (53) spaced apart from each other and surrounding the resonator at a distance; and an actuator (52) positioned in a region of the mounting substrate directly below the portion to which the connecting portion of the resonator is connected, with one direction in the plane formed by the mounting substrate being the x-direction and the other direction perpendicular to that direction being the y-direction, and displaceable in at least two directions, the x-direction and the y-direction, wherein the resonator has a first drive mode and a second drive mode along a direction different from the first drive mode in the resonant mode, and the actuator changes its position relative to the mounting substrate by being displaced in two directions.

[0008] This inertial sensor consists of a resonator, which is a three-dimensional curved oscillator, bonded to a mounting substrate. An actuator is positioned in the region of the mounting substrate directly below the connection point of the resonator. The actuator is displaced in at least two directions, the x and y directions, in the plane formed by the mounting substrate, thereby changing the position of the resonator. As a result, this inertial sensor can reduce fluctuations in the gap between the resonator and the multiple electrodes on the mounting substrate after the resonator and mounting substrate are bonded together.

[0009] One aspect of the present disclosure is a method for adjusting the position of a resonator in an inertial sensor, in which a resonator (2) having a curved surface portion (21) having an annular three-dimensional curved surface and a connecting portion (22) extending from the curved surface portion toward the center of the hemispherical shape formed by the curved surface portion is mounted on a mounting substrate (3), and the method includes driving an actuator (52) positioned in a region of the mounting substrate located directly below the portion to which the connecting portion of the resonator is connected, to change the position of the resonator with respect to the mounting substrate, wherein the position of the resonator is changed, and the radial direction with respect to the substrate radial direction (D1) is defined as the radial direction of the substrate, passing through the center of the resonator as viewed from the direction normal to the plane formed by the mounting substrate, and the distance in the substrate radial direction between the resonator and a plurality of electrode portions (53) surrounding the mounted resonator on the mounting substrate is defined as the inter-electrode distance (D1, D2), and the actuator is driven so as to minimize the difference between the maximum and minimum values ​​of the inter-electrode distance.

[0010] This position adjustment method involves driving an actuator located in the region of the mounting substrate directly below the connection point of the resonator in an inertial sensor in which a resonator, which is a three-dimensional curved oscillator, is bonded to a mounting substrate, to change the position of the resonator. The actuator is driven to minimize the difference between the maximum and minimum values ​​of the inter-electrode distance, which is the distance between one of the multiple electrode portions surrounding the mounted resonator on the mounting substrate and the resonator itself. This makes it possible to adjust the position of the resonator in a way that reduces fluctuations in the gap between the resonator and the multiple electrodes on the mounting substrate after the resonator has been bonded to the mounting substrate.

[0011] A position adjustment method according to another aspect of the present disclosure is a method for adjusting the position of a resonator in an inertial sensor, in which a resonator (2) having a curved surface portion (21) having an annular three-dimensional curved surface and a connecting portion (22) extending from the curved surface portion toward the center of the hemispherical shape formed by the curved surface portion is mounted on a mounting substrate (3), the method comprising driving an actuator (52) positioned in a region of the mounting substrate located directly below the portion to which the connecting portion of the resonator is connected, thereby changing the position of the resonator with respect to the mounting substrate, wherein the actuator is driven such that the difference between the maximum and minimum capacitance values ​​between one of the plurality of electrode portions and the portion of the resonator facing one of the electrode portions is minimized.

[0012] This position adjustment method involves driving an actuator located in the region of the mounting substrate directly below the connection point of the resonator in an inertial sensor in which a resonator, which is a three-dimensional curved oscillator, is bonded to a mounting substrate, to change the position of the resonator. The actuator is driven to minimize the difference between the maximum and minimum capacitance values ​​between one of the multiple electrode portions surrounding the mounted resonator on the mounting substrate and the resonator itself. This results in a resonator position adjustment method that can reduce fluctuations in the gap between the resonator and the multiple electrodes on the mounting substrate after the resonator has been bonded to the mounting substrate.

[0013] The reference numerals in parentheses attached to each component indicate an example of the correspondence between that component and the specific components described in the embodiments described later. [Brief explanation of the drawing]

[0014] [Figure 1] This is a cross-sectional view showing an inertial sensor according to the first embodiment. [Figure 2] This is a perspective cross-sectional view showing the portion of the inertial sensor in Figure 1 that is housed in the package. [Figure 3] This is a cross-sectional view showing an example of a resonator mounted on the inertial sensor shown in Figure 1. [Figure 4]It is a diagram illustrating an example of vibration modes of a resonator in the inertial sensor of FIG. 1, two drive modes in said vibration modes, and detection electrodes. [Figure 5] It is a first explanatory diagram of position adjustment of a resonator by driving an actuator. [Figure 6] It is a second explanatory diagram of position adjustment of a resonator by driving an actuator. [Figure 7] It is a cross-sectional view illustrating an inertial sensor according to a second embodiment. [Figure 8] It is a top view illustrating an actuator according to a second embodiment. [Figure 9] It is an arrow view seen from the direction IX in FIG. 8. [Figure 10] It is a cross-sectional view illustrating a modified example of the inertial sensor according to the second embodiment. [Figure 11] It is an enlarged cross-sectional view illustrating an actuator and a fixing portion related to an inertial sensor according to a third embodiment. MODE FOR CARRYING OUT THE INVENTION

[0015] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, portions that are the same or equivalent to each other are denoted by the same reference numerals in the description.

[0016] (First Embodiment) The inertial sensor 1 according to the first embodiment will be described with reference to FIGS. 1 to 6.

[0017] In FIG. 1, for ease of understanding the configuration of the inertial sensor 1, the outlines of a first electrode portion 53 and an electrode film 531 described later located in different cross sections are indicated by broken lines. In FIG. 2, for ease of understanding the configuration of the inertial sensor 1, a partial cross-sectional configuration of the resonator 2 is partially shown while omitting part of a lower substrate 4, an upper substrate 5, and the resonator 2, which will be described later, of the inertial sensor 1.

[0018] For the sake of clarity, as shown in Figure 2, one direction in the planar direction of the mounting substrate 3 will be referred to as the "x direction," the other direction perpendicular to that direction on the same plane will be referred to as the "y direction," and the direction normal to the xy plane will be referred to as the "z direction." The x, y, and z directions in figures other than Figure 2 correspond to the x, y, and z directions in Figure 2, respectively. Furthermore, in this specification, "up" refers to the direction along the z direction in the figures, meaning the side indicated by the arrow, and "down" refers to the opposite side of "up." In addition, in this specification, the view of the inertial sensor 1, resonator 2, or mounting substrate 3 from the upper side in the z direction will sometimes be referred to as a "top view."

[0019] [Basic configuration] The basic configuration of the inertial sensor 1 of this embodiment will now be described. As shown in Figure 1, for example, the inertial sensor 1 comprises a resonator 2, a mounting substrate 3, an actuator 52, a housing 6, and a cover material 7. The resonator 2, mounting substrate 3, and actuator 52 are housed in the housing 6 and covered by the cover material 7. The inertial sensor 1 can detect the angular velocity applied to it based on the change in capacitance between a part of the thin-walled resonator 2, which can vibrate in the first drive mode and the second drive mode described later, and a plurality of first electrode portions 53 of the mounting substrate 3.

[0020] In this embodiment, the resonator 2 is a micro-vibrating body with a three-dimensional symmetric structure, comprising a curved surface portion 21 including the outer shape of a substantially hemispherical three-dimensional curved surface, and a connecting portion 22 extending from the apex side of the virtual hemisphere formed by the curved surface portion 21 toward the center side of the hemisphere, as shown in Figure 3, for example. The resonator 2, for example, has a bowl-shaped three-dimensional curved surface for the curved surface portion 21, and its vibration Q value is 10 5 That's all.

[0021] In this embodiment, the resonator 2 has a base portion having a curved surface portion 21 and a connecting portion 22, which is made of a thermoplastic reflow material such as quartz glass, borosilicate glass, or other additive-containing glass, metallic glass, or silicon. The base portion of the resonator 2 is not limited to the above-mentioned material examples, as long as it is made of a reflow material that can form the three-dimensional curved surface portion 21 and the connecting portion 22 and can vibrate in wine glass mode. The resonator 2 is formed, for example, by processing a thin substrate made of the above-mentioned material through a forming process described later, so that the thickness of the curved surface portion 21 and the connecting portion 22 is on the order of micrometers, such as 10 μm to 100 μm. The resonator 2 has a millimeter-sized birdbath shape, for example, with a height dimension of 2.5 mm in the direction along the thickness direction of the mounting substrate 3, and an outer diameter of 5 mm on the surface 2a side of the rim 211 described later.

[0022] The resonator 2 is formed by setting a quartz plate with a thickness of 100 μm or less in a mold (not shown) which has a recess and a support column in the center of the recess that supports a part of the quartz plate when it is heated and softened. The curved surface portion 21 is formed by softening the plate with a heating means such as a flame and simultaneously evacuating the inside of the recess. For example, in this process, the part of the quartz plate supported by the support column of the mold (not shown) becomes a connection portion 22 that is recessed in a bottomed cylindrical shape relative to the curved surface portion 21, and the part that protrudes outward from the recess remains unprocessed but is removed in a later process. Then, for example, the recess of the mold (not shown) is returned to atmospheric pressure, and the quartz plate with the roughly hemispherical curved surface portion 21 is removed from the mold, and the quartz plate is sealed with a sealant made of any curable resin material. After that, for example, unnecessary parts of the quartz plate after processing, along with the sealant, are removed by polishing and CMP, and then all of the sealant is removed by any method such as heating or chemical solution, and the quartz plate is taken out. CMP is an abbreviation for Chemical Mechanical Polishing. The base of the resonator 2 is manufactured, for example, by the manufacturing process described above, but is not limited to this example, and other known methods may be employed. For example, the base of the resonator 2 may be formed by removing the unnecessary portion outside the curved portion 21 by laser processing without sealing the quartz plate on which the curved portion 21 and the connecting portion 22 are formed. Subsequently, the resonator 2 can be manufactured by depositing the surface electrode 23 on the base of the resonator 2 by any film deposition method.

[0023] The end of the curved surface portion 21 opposite to the connection portion 22 is designated as a rim 211, and the rim 211 is, for example, roughly cylindrical in shape. Here, "roughly cylindrical shape" includes not only cylindrical shapes where the diameter from the upper end to the lower end of the outer and inner surfaces of the rim 211 is the same, but also cylindrical shapes where the diameter from the upper end to the lower end varies. In other words, the curved surface portion 21 has a configuration in which the rim 211 is an annular portion of an annular curved surface. When the resonator 2 is mounted on the mounting substrate 3 with the side with the larger outer diameter as the front surface 2a and the opposite side as the back surface 2b, the rim 211 faces the multiple first electrode portions 53 on the mounting substrate 3 at a distance from the front surface 2a. The resonator 2 is mounted so that the distance between the rim 211 and the multiple first electrode portions 53 is equal. When the resonator 2 is mounted on the mounting substrate 3, the curved surface portion 21 including the rim 211 is a hollow state that does not come into contact with other components. In this embodiment, the resonator 2, when mounted on the substrate 3, has a structure in which the hollow rim 211 can vibrate in wineglass mode, and may also be referred to as an oscillator.

[0024] The connecting portion 22 is a part used for connecting to other components such as the mounting substrate 3, and is, for example, a bottomed cylindrical recess, but is not limited to this, and may be substantially columnar in shape. When the connecting portion 22 is a bottomed cylindrical recess, the bottom surface 22a of the recess on the surface 2a side may be a suction surface used for suction transport when mounting the resonator 2 onto the mounting substrate 3, for example. The surface of the connecting portion 22 opposite to the bottom surface 22a of the recess, that is, the back surface 2b side, is the mounting surface 22b that faces the mounting substrate 3.

[0025] The surface electrode 23 is composed of a laminated film consisting of, for example, an adhesion layer formed from chromium or titanium from the substrate side, and a conductive layer formed from any conductive material such as gold or platinum. The surface electrode 23 is deposited on the surface 2a and back surface 2b of the resonator 2 by any deposition method such as sputtering, vapor deposition, CVD, or ALD. CVD is an abbreviation for Chemical Vapor Deposition. ALD is an abbreviation for Atomic Layer Deposition. The surface electrode 23 is deposited on, for example, at least the mounting surface 22b and the surface 2a of the rim 211, and these parts are electrically connected. The surface electrode 23 may be in a solid shape that covers the entire surface of the front and back surfaces of the resonator 2, or it may be patterned by a method such as photolithography etching and cover a part of the front and back surfaces. The resonator 2 is connected to the actuator 52 on the mounting substrate 3 by means of a bonding method, such as a bonding method using a conductive material (not shown) to the portion of the surface electrode 23 that covers the mounting surface 22b of the connection portion 22, or by a metal bonding method.

[0026] The mounting substrate 3, as shown in Figure 1, for example, comprises a lower substrate 4 and an upper substrate 5, which are joined together. For example, the mounting substrate 3 can be obtained by etching and forming a wiring film on a lower substrate 4 made of borosilicate glass, an insulating material, then anodic bonding an upper substrate 5 made of silicon, a semiconductor material, to the lower substrate 4, and then patterning. The mounting substrate 3, for example, comprises on the upper substrate 5 side a plurality of inner frame portions 51, a plurality of first electrode portions 53 arranged apart from each other so as to surround the inner frame portions 51, and a second electrode portion 54 that surrounds the plurality of first electrode portions 53, away from them. The mounting substrate 3 also comprises, for example, on the lower substrate 4 side a ring-shaped groove 41 that surrounds the plurality of inner frame portions 51 while separating the plurality of inner frame portions 51 from the plurality of first electrode portions 53, and a plurality of wirings 42 that span the inside and outside of the groove 41.

[0027] The groove 41 is, for example, a groove provided between the inner frame portion 51 and the plurality of first electrode portions 53, as shown in Figure 2, and is formed by wet etching. The groove 41 is sized to correspond to the outer diameter of the rim 211 of the resonator 2 and is provided to prevent the rim 211 from coming into contact with the mounting substrate 3 when the resonator 2 is mounted on the mounting substrate 3.

[0028] The wiring 42 is made of a conductive material such as aluminum, and is arranged to pass between the multiple first electrode portions 53, and is electrically independent of the multiple first electrode portions 53. Multiple wirings 42 are provided, and on the lower substrate 4, they straddle the groove 41, with one end connected to the inner frame portion 51 and the other end connected to the second electrode portion 54, thus electrically connecting them. As a result, the mounting substrate 3 can apply voltage to the surface electrode 23 of the resonator 2 via the second electrode portion 54, the wiring 42, and the inner frame portion 51.

[0029] The inner frame portion 51 is formed, for example, by performing dry etching such as DRIE on the upper substrate 5 which is anodic-bonded to the lower substrate 4, together with a plurality of first electrode portions 53 and second electrode portions 54. DRIE is an abbreviation for Deep Reactive Ion Etching. The inner frame portion 51 is, for example, an annular shape when viewed from above, and is configured so that the connection portion 22 of the resonator 2 can be inserted into the enclosed area. In other words, the inner frame portion 51 is a frame shape that surrounds the area of ​​the mounting substrate 3 located directly below the mounting surface 22b of the resonator 2, which is called the direct-below region. The actuator 52 is arranged in the area enclosed by the inner frame portion 51.

[0030] In this embodiment, the actuator 52 is a drive device to which the resonator 2 is connected, and to which the portion connected to the resonator 2 is displaced in two directions, the x and y directions. The actuator 52 is, for example, a known piezoelectric, electrostatic, or electromagnetic type. The actuator 52 is, for example, directly manufactured within the area surrounded by the inner frame 51 of the mounting substrate 3 by a known actuator manufacturing method, with a diameter smaller than the inner diameter of the inner frame 51. The actuator 52 is, for example, connected to wiring (not shown) provided on the mounting substrate 3, and is capable of being displaced in the x direction, the y direction, or both directions by applying a voltage from an external power supply. The actuator 52 plays a role in changing the position of the resonator 2 and correcting the distance between the electrodes of the resonator 2 and the plurality of first electrode portions 53 when a misalignment occurs between the resonator 2 and the mounting substrate 3 due to the joining of the resonator 2 or changes over time after joining. A method for adjusting the position of the resonator 2 using the actuator 52 will be described later.

[0031] Furthermore, the actuator 52 may, for example, be manufactured separately from the mounting substrate 3 and then bonded to the mounting substrate 3 with a conductive adhesive (not shown) if the planar size of the mounting substrate 3 is 5 cm square or larger than a predetermined size.

[0032] The multiple first electrode portions 53 are arranged apart from each other, and, as shown in Figure 1, for example, an electrode film 531 is formed on the upper surface of each. The potential of the multiple first electrode portions 53 can be controlled by, for example, wires (not shown) being connected to the electrode film 531 and electrically connecting them to an external circuit board (not shown). The multiple first electrode portions 53 are arranged apart from each other at equal intervals, for example, in a top view, surrounding the rim 211 of the resonator 2 and forming a ring on the xy plane. When the resonator 2 is mounted, each of the multiple first electrode portions 53 is at a predetermined distance from the rim 211 of the resonator 2, and each forms a capacitor with the resonator 2. In other words, the mounting substrate 3 can detect the capacitance between itself and the resonator 2 via the multiple first electrode portions 53. Some of the multiple first electrode portions 53 are detection electrodes for detecting capacitance, with those located in the direction corresponding to the first drive mode of the resonator 2 being the first detection electrodes, and those located in the direction corresponding to the second drive mode being the second detection electrodes.

[0033] The second electrode portion 54 is, for example, a frame shape that surrounds the inner frame portion 51 and a plurality of first electrode portions 53 arranged around it when viewed from above. The second electrode portion 54 has, for example, at least one electrode film 541 made of aluminum or the like on its upper surface, and a wire (not shown) is connected to the electrode film 541. The second electrode portion 54 is connected to the surface electrode 23 of the resonator 2 via at least wiring 42 and can be configured to which a voltage can be applied. It may have a shape other than a frame shape, and multiple second electrode portions may be arranged. Its shape and arrangement can be changed as appropriate.

[0034] The housing 6 is a package component whose base is made of an insulating material such as ceramic, and which houses at least the resonator 2 and the mounting substrate 3. The housing 6 has, for example, electrode pads (not shown), internal wiring and external terminals, and is connected to the first electrode portion 53, the second electrode portion 54 and the actuator 52 of the mounting substrate 3 by wires or wiring, and has a structure that allows these to be electrically connected to an external power supply.

[0035] The cover material 7 is attached to the housing 6 by an adhesive (not shown) and is a component that covers the opening of the housing space for the resonator 2 and the mounting substrate 3 within the housing 6. The cover material 7 may be made of the same insulating material as the housing 6, or it may be made of a different insulating material. In this embodiment, the cover material 7, together with the housing 6, constitutes a package material that encloses the resonator 2 and the mounting substrate 3 of the inertial sensor 1.

[0036] The above describes the basic configuration of the inertial sensor 1. However, the inertial sensor 1 is not limited to the above configuration, and some configurations of the resonator 2 and the mounting substrate 3 may be changed. For example, the resonator 2 may not only have the lower surface of the rim 211 facing the z direction and the mounting surface 22b of the connection portion 22 located on the same plane, but may also have a configuration in which the rim 211 protrudes beyond the mounting surface 22b, or the mounting surface 22b protrudes beyond the rim 211. For example, if the resonator 2 has a configuration in which the mounting surface 22b protrudes more than the rim 211, the mounting substrate 3 may not have a groove 41.

[0037] [Adjusting the position of the resonator] First, an example of the vibration modes of resonator 2 and the assignment of the detection electrodes will be explained with reference to Figure 4.

[0038] In Figure 4, for clarity, the outer outline of the rim 211 of the resonator 2 in the resonant modes described later is shown with a dashed line for the first drive mode, a double dashed line for the second drive mode, and a dashed line for intermediate states. Also in Figure 4, although it does not show a cross-section, hatching is applied to the first and second detection electrodes 53A and 53B to make them easier to understand. The same applies to Figure 6, which will be described later.

[0039] The resonator 2 vibrates in the xy-plane direction when, for example, an electrostatic force is applied from a portion of the multiple first electrode portions 53. When the resonator 2 is vibrated at a predetermined resonant frequency, it enters a vibration mode in which, as shown in Figure 4, for example, the antinodes and nodes in the vibration amplitude of the outer surface of the rim 211 are the same n (n: an integer of 2 or more) when viewed from above.

[0040] The vibration mode of the resonator 2 shown in Figure 4 is a resonant mode where n=2, and in this specification, it may be referred to as the "n=2 mode". The following explanation will describe the case where the resonator 2 is in n=2 mode when the inertial sensor 1 is operating as a representative example, but the resonator 2 may also be in a higher-order resonant mode of n=3 or higher.

[0041] In the resonator 2, for example in the n=2 mode, two different vibration modes are generated: a first drive mode in the direction indicated by the solid arrow and a second drive mode in the direction indicated by the dashed arrow, as shown in Figure 4, and these vibration modes alternate. The second drive mode occurs in a direction tilted at a predetermined angle relative to the direction of the first drive mode when viewed from above. For example, the second drive mode occurs in a direction tilted at a predetermined angle corresponding to the resonance mode relative to the first drive mode, such as 45° in the n=2 mode, 30° in the n=3 mode, and 22.5° in the n=4 mode. When the resonator 2 is in the resonance mode, the first electrode portion 53 located in the direction of the first drive mode is assigned as the first detection electrode 53A, and the one located in the direction of the second drive mode is assigned as the second detection electrode 53B. As a result, when external rotation is applied to the inertial sensor 1, it becomes possible to detect the angular velocity and rotation angle based on the change in capacitance between the detection electrodes 53A, 53B and the resonator 2.

[0042] Next, the position adjustment of the resonator 2 using the actuator 52 will be explained with reference to Figures 5 and 6.

[0043] Figures 5 and 6 show a top view of the multiple first electrode sections 53 and the resonator 2. To make the position of the resonator 2 easier to understand, only the outer edge of the rim 211 of the resonator 2 is shown with solid and dashed lines. In addition, in Figures 5 and 6, the outer edge of the rim 211 before position adjustment by the actuator 52 is shown with a dashed line, and the outer edge of the rim 211 in a state where there is no positional displacement of the resonator 2 or after position adjustment is shown with a solid line.

[0044] Preferably, the resonator 2 is arranged such that, as shown by the solid line in Figure 5, the distance between the multiple first electrode portions 53 and the surface electrode 23 covering the rim 211, i.e., the inter-electrode distance, is equal when viewed from above. In this case, there is no capacitance orientation error between the rim 211 of the resonator 2 and the first electrode portions 53, and the sensor accuracy of the inertial sensor 1 is improved. However, as shown by the dashed line in Figure 5, for example, the resonator 2 may shift relative to the mounting substrate 3 when it is bonded to the mounting substrate 3, or due to changes over time after it has been bonded to the mounting substrate 3. In this case, for example, the resonator 2 may have a center C1 at a different position from the center C0, where C0 is the center at which the inter-electrode distance is equal.

[0045] For the sake of simplicity, the following explanation will simply refer to any misalignment of the resonator 2 relative to the mounting substrate 3, which is caused by bonding to the mounting substrate 3 or by changes over time after bonding, as "misalignment of the resonator 2".

[0046] If the resonator 2 is misaligned relative to the other resonator 2, the distance between the multiple first electrode portions 53 and the resonator 2 becomes asymmetric, i.e., uneven, resulting in capacitance orientation errors and thus reducing the sensor accuracy of the inertial sensor 1. Therefore, the inertial sensor 1 is configured to correct the distance between the first electrode portions 53 and the rim 211 of the resonator 2 by driving the actuator 52 to which the resonator 2 is connected, for example, by displacing it in the xy-plane direction and moving the center C1 to the position of the center C0. The position of the resonator 2 relative to the mounting substrate 3 is corrected, for example, by the first to fourth position adjustment methods described below.

[0047] The first position adjustment method is a method of moving the resonator 2 by driving the actuator 52 to minimize the difference between the maximum value and the minimum value of the inter-electrode distance between the resonator 2 and the first electrode section 53.

[0048] Hereinafter, for convenience of description, as shown in FIG. 6, the radial direction centered on an imaginary straight line that passes through the center C0 of the resonator 2 when viewed from above and extends along the z-direction which is the thickness direction of the mounting board 3 is referred to as "board radial direction D A ". In FIG. 6, for ease of visualization, the board radial direction D A only shows one of them, but all 360° directions spreading radially starting from the center C0 on the plane of the drawing correspond to the board radial direction D A . The center C1 of the resonator 2 before adjustment and the center C0 of the resonator 2 after adjustment correspond to the center position of the recess bottom surface 22a or the mounting surface 22b when viewed from above.

[0049] Here, the inter-electrode distance refers to the distance between the first electrode section 53 and the surface electrode 23 covering the portion of the rim 211 facing the first electrode section 53 in the board radial direction D A . The inter-electrode distance can be obtained, for example, by a method of analyzing an image obtained by an imaging device such as a camera (not shown) using a known image recognition technique, or a method of inversely calculating the distance from capacitance. First, immediately after the resonator 2 is bonded to the mounting board 3, or when a predetermined period of time has elapsed after bonding, the inter-electrode distance is calculated. If there is variation in the inter-electrode distance, the actuator 52 is driven to adjust the position of the resonator 2. For example, as shown in FIG. 6, among the first electrode sections 53, the one with the largest inter-electrode distance is defined as the maximum distance D max and the one with the smallest inter-electrode distance is defined as the minimum distance D min . The actuator 52 moves the resonator 2 such that the difference between the maximum distance D max and the minimum distance D min is minimized. This reduces variation in the inter-electrode distance between the resonator 2 and the plurality of first electrode sections 53, making it possible to maintain high sensor accuracy of the inertial sensor 1.

[0050] The resonator 2 may be positioned by a second position adjustment method. The second position adjustment method is a method of adjusting the distance between the resonator 2 and the first electrode section 53 so that it is equal along the first axis and the second axis. Here, the first axis and the second axis refer to the direction along the first drive mode and the direction along the second drive mode in the resonant mode, respectively. In other words, in the second position adjustment method, the distance between the resonator 2 and the first detection electrode 53A is taken as distance D1, and the distance between the resonator 2 and the second detection electrode 53B is taken as distance D2, and the actuator 52 is driven to move the resonator 2 so that distances D1 and D2 are equal. This reduces the variation in the distance between the resonator 2 and at least the detection electrodes 53A and 53B among the multiple first electrode sections 53, making it possible to maintain high sensor accuracy of the inertial sensor 1.

[0051] The resonator 2 may be positioned by a third position adjustment method. The third position adjustment method is a method of adjusting so that the difference between the maximum and minimum capacitance values ​​between the resonator 2 and the plurality of first electrode portions 53 is minimized. This reduces the variation in capacitance between the resonator 2 and the plurality of first electrode portions 53, i.e., the variation in the distance between electrodes, and makes it possible to maintain high sensor accuracy of the inertial sensor 1.

[0052] The resonator 2 may be adjusted in position by a fourth position adjustment method. The fourth position adjustment method is a method of adjusting the capacitance between the resonator 2 and the first electrode portion 53 so that it is equal in the first axis and the second axis. This reduces the variation in capacitance between the resonator 2 and at least the detection electrodes 53A and 53B among the multiple first electrode portions 53, making it possible to maintain high sensor accuracy of the inertial sensor 1.

[0053] According to this embodiment, the resonator 2 is joined to the actuator 52 of the mounting substrate 3, and by driving the actuator 52, the position of the resonator 2 becomes an inertial sensor 1 that can be adjusted after joining with the mounting substrate 3. Therefore, even if a relative positional shift occurs in the resonator 2, the orientation error of the capacitance in the multiple first electrode portions 53 can be reduced by any of the first to fourth position adjustment methods described above, thereby improving the accuracy of the sensor.

[0054] (Second Embodiment) The inertial sensor 1 of the second embodiment will be described with reference to Figure 7.

[0055] The inertial sensor 1 of this embodiment differs from the first embodiment in that the configuration of the actuator 52 has been partially modified, as shown in Figure 7, for example. This embodiment will mainly describe this difference.

[0056] In this embodiment, the actuator 52 includes, for example, a first displacement portion 521 which is a part that displaces in the xy plane, and a plurality of second displacement portions 522 which displace in the z direction, as shown in Figure 7. The actuator 52 can change the position of the resonator 2 in the xy plane by the first displacement portion 521, and can control the tilt of the resonator 2 by the second displacement portions 522.

[0057] The actuator 52 has three second displacement parts 522, as shown in Figure 8, for example. The second displacement parts 522 are, for example, rectangular columnar in a top view, but are not limited to this, and their shape and dimensions can be changed as appropriate. The actuator 52 is configured such that three second displacement parts 522 are formed on a first displacement part 521, and the three second displacement parts 522 are arranged at approximately equal intervals, as shown in Figure 9, for example. The actuator 52 has a connection part 22 of the resonator 2 joined to the three second displacement parts 522, and the tilt of the resonator 2 is adjusted by individually displacing the three second displacement parts 522 in the z direction. The second displacement parts 522 move in the xy plane direction in conjunction with the displacement of the first displacement part 521, and are also displaced in the z direction. The second displacement parts 522 are configured such that, for example, an electrode (not shown) is formed on the tip surface, which is independent of the electrode used for displacement in the z direction, and the potential of the surface electrode 23 of the resonator 2 can be adjusted.

[0058] Although Figure 7 and other figures show an actuator 52 having three second displacement parts 522, the actuator 52 is not limited to this configuration, and the number and arrangement of the second displacement parts 522 may be changed as appropriate. For example, the actuator 52 may have two second displacement parts 522 and one support part that is similar in shape to the second displacement parts 522 but does not displace, or it may have four or more second displacement parts 522.

[0059] According to this embodiment, in addition to the effects of the first embodiment described above, the inertial sensor 1 also allows for adjustment of the tilt of the resonator 2.

[0060] (Modified version of the second embodiment) As shown in Figure 10, for example, the inertial sensor 1 has multiple first electrode portions 53 that are in the radial direction D of the rim 211 and the substrate. A The inertial sensor may be formed not at a position opposite to the rim 211 along the z-axis, but at a position opposite to the rim 211 in the z-direction. In this case, the inertial sensor 1 will be configured to generate a vibration mode of the rim 211 in the z-direction and to detect the amplitude of that vibration.

[0061] This modified example also provides an inertial sensor 1 that offers the same effects as the second embodiment described above.

[0062] (Third embodiment) The inertial sensor 1 of the third embodiment will be described with reference to Figure 11. In Figure 11, for ease of viewing, a portion of the actuator 52 and the fixed portion 55, which will be described later, of the inertial sensor 1 are shown in an enlarged view, while other parts of the sensor are omitted.

[0063] The inertial sensor 1 of this embodiment differs from the first embodiment in that the mounting substrate 3 further includes a fixing portion 55 that fixes the actuator 52 in a displaced state, as shown in Figure 11, for example. This embodiment will mainly explain this difference.

[0064] In this embodiment, the inertial sensor 1 further includes a fixing portion 55 that engages with a part of the actuator 52 when the actuator 52 is displaced in the xy-plane direction, as shown in Figure 11, for example, and fixes the actuator 52 in the displaced state.

[0065] In this embodiment, the actuator 52 has a fitting portion 523 formed on a part of the part that is displaced in the x or y direction, as shown in Figure 11, for example, which fits with the fixed portion 55. The fitting portion 523 is, for example, a sawtooth or comb-like shape with repeated triangular protrusions. The fitting portion 523 is shaped such that, for example, it does not fit with the fixed portion 55 when the actuator 52 is displaced, but fits with the fixed portion 55 when the actuator 52 is in the off state and tries to return in the opposite direction to the direction in which it was displaced. In other words, the fitting portion 523 is paired with the fixed portion 55 and together with the fixed portion 55 forms a ratchet mechanism.

[0066] The fixed portion 55 is independent of the displacement portion of the actuator 52 and is a part that is fixed to the mounting substrate 3 and does not move. The fixed portion 55 is made of any material, such as a semiconductor material such as silicon, or a metallic material, similar to the base portion of the first electrode portion 53. The fixed portion 55 is formed directly on the mounting substrate 3, similar to the actuator 52. The fixed portion 55 has, for example, a projection 551, which is positioned opposite the displacement portion of the actuator 52, and the projection 551 is in contact with the fitting portion 523 of the actuator 52. If the fitting portion 523 is configured with a plurality of substantially right-angled triangular projections arranged in a continuous and repeated manner, the projection 551 of the fixed portion 55 is substantially right-angled triangular in shape. In this case, for example, the inclined surface 551a of the projection 551 of the fixed portion 55 faces the inclined surface 523a of the fitting portion 523, and the inclined surface 551a is positioned substantially parallel to the inclined surface 523a. Furthermore, the inclined surface 551a of the projection 551 and the inclined surface 523a of the fitting portion 523 are tilted with respect to the displacement direction when the actuator 52 is in the ON state. As a result, when the actuator 52 is displaced, the fixing portion 55 does not engage with the fitting portion 523 and does not hinder the displacement of the actuator 52.

[0067] On the other hand, the adjacent surface 551b of the projection 551 that is adjacent to the inclined surface 551a extends, for example, in a direction perpendicular to the displacement direction of the actuator 52. Similarly, the adjacent surface 523b of the fitting portion 523 that is adjacent to the inclined surface 523a extends in a direction perpendicular to the displacement direction of the actuator 52, and faces the adjacent surface 551b. As a result, the fixing portion 55 engages with the adjacent surface 551b of the projection 551 and the adjacent surface 523b of the fitting portion 523, playing a role in preventing the actuator 52 from moving in the opposite direction to the displacement direction. Therefore, even when the actuator 52 is turned off after being driven, the fixing portion 55 fixes the actuator 52 in the position after displacement and constitutes part of a ratchet mechanism that prevents the resonator 2 from returning to its original position before displacement. The number and arrangement of the fixing portions 55 can be appropriately changed depending on the form of the fitting portion 523.

[0068] This embodiment also provides the same effects as the first embodiment, but with the addition of a fixing portion 55 and a fitting portion 523, the inertial sensor 1 can also be made capable of fixing the resonator 2 to the position adjusted by the actuator 52.

[0069] (Other embodiments) This disclosure is described in accordance with the embodiments, but it is understood that this disclosure is not limited to such embodiments or structures. This disclosure also includes various modifications and variations within the equivalence range. In addition, various combinations and forms, as well as other combinations and forms including one, more, or less of those elements, fall within the scope and concept of this disclosure.

[0070] It goes without saying that, in each of the above embodiments, the elements constituting the embodiment are not necessarily essential unless explicitly stated to be particularly essential or unless they are clearly considered essential in principle. Furthermore, in each of the above embodiments, when numerical values ​​such as the number, numerical values, quantities, or ranges of the components of the embodiment are mentioned, the embodiment is not limited to those specific numbers unless explicitly stated to be particularly essential or unless it is clearly limited to a specific number in principle. Furthermore, in each of the above embodiments, when the shape, positional relationship, etc., of the components are mentioned, the embodiment is not limited to those shapes, positional relationships, etc., unless explicitly stated or unless it is clearly limited to a specific shape, positional relationship, etc., in principle. [Explanation of Symbols]

[0071] 2...Resonator, 21...Curved section, 22...Connection section, 3...Mounting board, 52...Actuator 521...First displacement section, 522...Second displacement section, 53...First electrode section, 53A...First detection electrode 53B...Second detection electrode, 55...Fixed part, D A ...surface radial direction

Claims

1. It is an inertial sensor, A resonator (2) having a curved surface portion (21) having an annular three-dimensional curved surface, and a connecting portion (22) extending from the curved surface portion toward the center of the hemispherical shape formed by the curved surface portion, A mounting substrate (3) having a plurality of electrode portions (53) that are spaced apart from each other and surround the resonator at a distance from each other, The mounting substrate comprises an actuator (52) positioned in a region of the mounting substrate located directly below the portion to which the connection portion of the resonator is connected, with one direction in the plane formed by the mounting substrate being the x-direction, and the other direction perpendicular to the one direction in the plane being the y-direction, and the actuator (52) being displaceable in at least two directions, the x-direction and the y-direction, The resonator has, in its resonant mode, a first drive mode and a second drive mode along a direction different from that of the first drive mode. The actuator is an inertial sensor that changes the position of the actuator relative to the mounting substrate by being displaced in the two directions.

2. The inertial sensor according to claim 1, wherein the actuator further comprises a first displacement portion (521) which is displaced in the two directions, and a plurality of second displacement portions (522) which are displaced in the z direction, with the direction perpendicular to the plane being the z direction.

3. The inertial sensor according to claim 1 or 2, wherein the actuator further comprises a fixing portion (55) capable of fixing the portion that displaces in the two directions to the displaced position.

4. A method for adjusting the position of a resonator in an inertial sensor, wherein the resonator (2) is mounted on a mounting substrate (3) and has a curved surface portion (21) having an annular three-dimensional curved surface and a connecting portion (22) extending from the curved surface portion toward the center of the hemispherical shape formed by the curved surface portion, This includes driving an actuator (52) located in a region of the mounting substrate directly below the portion to which the connection portion of the resonator is connected, thereby changing the position of the resonator relative to the mounting substrate. In changing the position of the resonator, the radial direction is defined as the substrate radial direction (D), with the axis of a virtual straight line passing through the center of the resonator as viewed from the direction normal to the plane formed by the mounting substrate and along the normal direction. Ａ A position adjustment method comprising: setting the distance between the multiple electrode portions (53) surrounding the mounted resonator on the substrate and the resonator in the radial direction of the substrate as the inter-electrode distance (D1, D2), and driving the actuator so as to minimize the difference between the maximum and minimum values ​​of the inter-electrode distance.

5. The position adjustment method according to claim 4, wherein, in changing the position of the resonator, the electrode portion located in a direction along the first drive mode when the resonator is vibrated in a resonant mode is designated as the first detection electrode (53A), and the electrode portion located in a direction along the second drive mode, which is a vibration mode in a direction different from the first drive mode, is designated as the second detection electrode (53B), and the actuator is driven so that the distance between the electrodes of the resonator and the first detection electrode is equal to the distance between the electrodes of the resonator and the second detection electrode.

6. A method for adjusting the position of a resonator in an inertial sensor, wherein the resonator (2) is mounted on a mounting substrate (3) and has a curved surface portion (21) having an annular three-dimensional curved surface and a connecting portion (22) extending from the curved surface portion toward the center of the hemispherical shape formed by the curved surface portion, This includes driving an actuator (52) located in a region of the mounting substrate directly below the portion to which the connection portion of the resonator is connected, thereby changing the position of the resonator relative to the mounting substrate. A position adjustment method for changing the position of the resonator, comprising driving the actuator such that the difference between the maximum and minimum capacitance values ​​between one of the multiple electrode portions (53) of the mounting substrate surrounding the resonator and the portion of the resonator facing the one electrode portion is minimized.

7. In changing the position of the resonator, the electrode portion located in a direction along the first drive mode when the resonator is vibrated in a resonant mode is designated as the first detection electrode (53A), and the electrode portion located in a direction along the second drive mode, which is a vibration mode in a direction different from the first drive mode, is designated as the second detection electrode (53B), and the actuator is driven so that the capacitance between the resonator and the first detection electrode is equal to the capacitance between the resonator and the second detection electrode, according to claim 6.

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