JP2012242240A - Gyro sensor, electronic apparatus - Google Patents

Abstract

A gyro sensor that is miniaturized is provided.
An outer mass portion having a first cavity portion, an inner mass portion provided in the first cavity portion and having a second cavity portion, and an outer mass portion being an inner mass portion. Drive unit 70 that is driven integrally with 16 in the direction of the first axis, and is connected between the outer mass unit 14 and the inner mass unit 16 and can be displaced in the direction of the second axis perpendicular to the direction of the first axis. A spring part 20; a first detection part (detection part 30) provided in the second cavity part 17 for detecting an angular velocity around the axis of the first axis; and a vibrating body 40 provided in the second cavity part 17; The vibrating body 40 is a cantilever support structure in which one end is connected to the inner wall of the second cavity portion 17 and is extended in the direction of the first axis and the other end is floated. Along with the drive vibration, the vibrating body 40 can vibrate in the third axis direction perpendicular to the first axis and the second axis.
[Selection] Figure 2

Description

  The present invention relates to a gyro sensor and an electronic device using the gyro sensor.

  In recent years, gyro sensors that detect angular velocities are often used for attitude control such as car navigation systems and camera shake correction for video cameras. Such a gyro sensor includes a sensor provided on each axis with a detection element capable of detecting angular velocities around the X, Y, and Z axes orthogonal to each other.

  The gyro sensor disclosed in Patent Document 1 is a multi-axis angular velocity sensor that detects angular velocities with respect to first to third detection axes orthogonal to each other, and is a first vibrating angular velocity that detects angular velocities with respect to the first detection axis. A sensor element; a second vibration-type angular velocity sensor element that detects an angular velocity with respect to the second detection axis; a third vibration-type angular velocity sensor element that detects an angular velocity with respect to the third detection axis; An IC that controls the vibration-type angular velocity sensor element, first to third vibration-type angular velocity sensor elements, and a package that accommodates the IC are provided, and the vibration plane of the first vibration-type angular velocity sensor element and the first detection axis are parallel to each other. The vibration plane of the second vibration type angular velocity sensor element and the second detection axis are parallel, and the vibration plane of the third vibration type angular velocity sensor element and the third detection axis are orthogonal to each other. Multi-axial angular velocity sensor which is low profile is disclosed.

JP 2010-266321 A

  However, since the conventional gyro sensor detects angular velocities around three axes, if each axis is arranged in the chip, the mounting area becomes large, and the sensor element can be further miniaturized in response to the demand for miniaturization of the entire device. There was no problem.

  In addition, since vibration is independent for each one-axis angular velocity sensor, a drive circuit must be provided for each angular velocity sensor, and an integrated circuit (IC) is also required separately, which increases the mounting area and reduces the size of the sensor. It was difficult. In addition, since vibration modes exist for each of a plurality of angular velocity sensors, there is a problem in that they interfere with each other.

  In order to solve the above-described problems of the conventional technology, an object of the present invention is to provide a gyro sensor that is miniaturized.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following application examples.

[Application Example 1] An outer mass portion having a first cavity portion, an inner mass portion provided in the first cavity portion of the outer mass portion and having a second cavity portion, and the outer mass portion as described above A drive unit that is driven in the direction of the first axis integrally with the inner mass unit, and is connected between the outer mass unit and the inner mass unit, and is displaced in the direction of the second axis perpendicular to the direction of the first axis. A possible spring portion, a first detection portion that is provided in the second cavity portion of the inner mass portion and detects an angular velocity around the axis of the first axis, and is provided in the second cavity portion of the inner mass portion. A vibration system structure including the vibration body, the vibration body having one end connected to the inner wall of the second cavity portion of the inner mass portion and extending in the direction of the first axis. A cantilever support structure with the other end floating, and the vibration body moves relative to the first axis and the second axis along with the driving vibration in the direction of the first axis. Gyro sensor, characterized in that possible vibrations on the third axis direction perpendicular.
The gyro sensor having such a configuration includes a vibrating body that vibrates in the third axis direction orthogonal to the plane formed by the first axis and the second axis in accordance with the driving vibration, and thus the vibration in the third axis direction is surfaced. By using it as driving vibration for detecting the inner axis, it is possible to detect the angular velocity around the same axis as the driving direction horizontal to the plane. Therefore, if the gyro sensor element of this application example is used in combination, multi-axis detection with the driving direction as one direction can be performed, and the element can be downsized.

Application Example 2 The gyro sensor according to Application Example 1, wherein the vibrating body is provided with a frequency adjustment unit.
According to the above configuration, the drive vibration of the drive unit and the vibration frequency of the vibrating body can be matched, and a desired drive amplitude can be obtained.

Application Example 3 The gyro sensor according to Application Example 2, wherein the frequency adjustment unit is provided on the other end side of the vibrating body.
According to the above configuration, since the frequency can be greatly changed by providing the frequency adjustment unit on the other end side of the vibrating body, the frequency adjustment can be easily performed.

Application Example 4 The gyro sensor according to Application Example 2 or 3, wherein the frequency adjusting unit is provided with a metal film.
According to the above configuration, the frequency adjustment can be easily performed by scraping the metal film provided in the frequency adjustment unit with a laser or the like.

Application Example 5 The gyro sensor according to any one of Application Examples 1 to 4, wherein the vibrator has a rigidity on the one end side smaller than a rigidity on the other end side.
According to the above configuration, it is possible to increase the amplitude of vibration of the vibrating body accompanying drive vibration, to generate a large Coriolis force when rotation is applied, and to improve sensitivity.

  Application Example 6 The gyro sensor according to any one of Application Examples 1 to 5, wherein the vibrating body is provided with a weight portion on the other end side.

Application Example 7 The gyro sensor according to any one of Application Examples 1 to 6, wherein the vibrating body is provided with a groove or a through hole on the one end side.
According to the above configuration, for example, a weight is provided at the tip of the vibrating body, or a through hole or a groove is provided on the fixed end side of the vibrating body so that the rigidity on the solid end side of the vibrating body is set to the rigidity on the free end side. The angular velocity generated by the rotation acting around the axis can be detected with high sensitivity.

Application Example 8 The outer mass portion is disposed above the substrate, and the first detection unit includes a fixed electrode provided on the substrate and a movable electrode provided on the inner mass portion. The gyro sensor according to any one of Application Examples 1 to 7, wherein the gyro sensor includes:
According to the above configuration, the angular velocity generated by the rotation acting around the axis can be detected with high sensitivity.

Application Example 9 Arranging the vibration system structures in the direction of the first axis, connecting the vibration system structures with a spring that couples the vibration system structures, and causing the vibration system structures to vibrate in opposite directions. The gyro sensor according to any one of application examples 1 to 8, characterized by:
According to the above configuration, the vibration balance is improved, and the angular velocity generated by the rotation acting around the axis can be detected with high sensitivity.

[Application Example 10] The extension direction of the vibration body of one vibration system structure and the extension direction of the vibration body of the other vibration system structure are reversed, and the vibration of one of the vibration system structures is reversed. 10. The gyro sensor according to application example 9, wherein the sum of the output signal of the system structure and the output signal of the other vibration system structure is taken.
According to the above configuration, only the desired angular velocity can be detected by removing the angular velocity component of the other axis. Therefore, the angular velocity can be detected with higher accuracy than in the first application example.

Application Example 11 The direction of the extension of the vibration body of one vibration system structure is the same as the direction of the extension of the vibration body of the other vibration system structure, and the one vibration The gyro sensor according to application example 9, wherein a difference between an output signal of a system structure and an output vibration of the other vibration system structure is taken.
According to the above configuration, only the desired angular velocity can be detected by removing the force of the acceleration component. Therefore, the angular velocity can be detected with higher accuracy than in the first application example.

Application Example 12 In the vibration system structure, a second detection unit that detects at least one of angular velocities around the second axis and the third axis is provided. The gyro sensor of any one of thru | or 11.
According to the above configuration, multi-axis detection with the driving direction as one direction is possible, and the driving unit can be shared, so that the entire sensor can be downsized.

Application Example 13 An electronic device comprising the gyro sensor according to any one of Application Examples 1 to 12.
According to the above configuration, it is possible to reduce the size of the drive unit for multi-axis detection in common, and to obtain an electronic device including a gyro sensor that can detect angular velocity with high accuracy.

It is explanatory drawing which shows the structure outline of the gyro sensor of this invention. It is explanatory drawing which shows the structure outline of the sensor element which can detect the rotation which acts around an X-axis. It is explanatory drawing of the modifications 1-4 of a vibrating body. It is explanatory drawing of a frequency adjustment part, (1) is a perspective view, (2) is aa sectional drawing of (1). It is explanatory drawing which detects the rotation which acts around an X-axis, (1) is a perspective view, (2) is bb sectional drawing of (1). It is explanatory drawing which detects the rotation which acts around a Y-axis, (1) is a perspective view, (2) is cc sectional drawing of (1). It is explanatory drawing which detects the rotation which acts around a Z-axis. It is explanatory drawing of the integrated circuit of a gyro sensor. It is explanatory drawing of the mobile telephone to which the electronic device provided with the gyro sensor of this invention is applied.

  Embodiments of a gyro sensor and an electronic apparatus of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is an explanatory diagram showing a schematic configuration of a gyro sensor of the present invention. In each figure, for convenience of explanation, an X axis, a Y axis, and a Z axis are illustrated as three axes orthogonal to each other. In this embodiment, the direction parallel to the X axis (first axis) is the X axis direction, the direction parallel to the Y axis (second axis) is the Y axis direction, and the direction parallel to the Z axis (third axis) is Z. It is called the axial direction.

The gyro sensor 10 shown in FIG. 1 can detect a sensor element 100 that can detect rotation acting around the X axis, a sensor element 200 that can detect rotation acting around the Y axis, and a rotation acting around the Z axis. A sensor element 300 is provided.
FIG. 2 is an explanatory diagram showing a schematic configuration of a sensor element capable of detecting rotation acting around the X axis. The sensor element 100 shown in FIG. 2 drives the outer mass portion 14 formed on the vibration system structure 12, the drive spring portion 60, the inner mass portion 16 surrounded by the outer mass portion 14, and the outer mass portion 14. Supported by the driving unit 70, the spring unit 20 connecting the outer mass unit 14 and the inner mass unit 16, the detection unit 30 as a first detection unit capable of detecting displacement around the axis, and the inner mass unit 16. The vibrating body 40 is the main basic configuration.

  The vibration system structure 12 serving as a substrate is composed of silicon as a main material, and is formed on a silicon substrate (silicon wafer) with a thin film formation technique (for example, deposition techniques such as an epitaxial growth technique and a chemical vapor deposition technique) and various processes. Each part mentioned above is integrally formed by processing into a desired external shape using techniques (for example, etching techniques, such as dry etching and wet etching). Alternatively, after the silicon substrate and the glass substrate are bonded together, only the silicon substrate is processed into a desired outer shape, whereby the above-described portions can be formed. By using silicon as the main material of the vibration system structure 12, excellent vibration characteristics can be realized and excellent durability can be exhibited. Further, it becomes possible to apply a fine processing technique used for manufacturing a silicon semiconductor device, and the gyro sensor 10 can be downsized.

  The outer mass portion 14 includes a first cavity portion 15 on the inner side, and is a substantially rectangular frame body in plan view with the Z axis as a normal line. In the present embodiment, both the outer mass portion 14 and the inner mass portion 16 have a frame shape, but shapes other than the frame shape are also applicable. The outer mass portion 14 is connected to the drive spring portion 60 at a side surface that intersects the X axis in a plan view with the Z axis as a normal line.

  The drive spring portion 60 connects the outer mass portion 14 and the fixed portion 50. The drive spring part 60 is composed of first and second drive spring parts 62 and 64. The first drive spring portion 62 includes a pair of first drive spring portions 62a and 62b, and each first drive spring portion 62a and 62b has a shape extending in the X-axis direction while reciprocating in the Y-axis direction. There is no. The first drive spring portions 62a and 62b are provided symmetrically with respect to the Y axis that intersects the center C of the outer mass portion 14 in a plan view with the Z axis as a normal line. By forming the first drive spring portions 62a and 62b in such a shape, the first drive spring portion 62 is prevented from being deformed in the Y-axis direction and the Z-axis direction, and the drive direction A is the X-axis direction. Can be expanded and contracted smoothly.

  The configuration of the second drive spring portion 64 is provided symmetrically with the first drive spring portion 62 with respect to the X axis that intersects the center C of the outer mass portion 14, and a pair of second drive spring portions 64a and 64b. It is composed of By forming each of the second drive spring portions 64a and 64b in such a shape, the second drive spring portion 64 is smoothly deformed in the X-axis direction, which is the drive direction, while suppressing deformation in the Y-axis direction and the Z-axis direction. Can be expanded and contracted.

  The inner mass portion 16 is provided in the first cavity portion 15 of the outer mass portion 14, and the outer periphery is surrounded by the outer mass portion 14. Note that a second cavity portion 17 is formed inside the inner mass portion 16. The inner mass portion 16 is a substantially rectangular frame in plan view with the Z axis as a normal line, and the side surface intersecting the Y axis is connected to the outer mass portion 14 via the spring portion 20.

  The spring portion 20 includes first and second spring portions 22 and 24. The first spring portion 22 includes a pair of first spring portions 22a and 22b, and each first spring portion 22a and 22b has a shape extending in the Y-axis direction while reciprocating in the X-axis direction. . The first spring portions 22a and 22b are provided symmetrically with respect to the X axis that intersects the center C of the outer mass portion 14 in a plan view with the Z axis as a normal line. By forming the first spring portions 22a and 22b in such a shape, the first spring portion 22 can be smoothly expanded and contracted in the Y-axis direction as the detection direction while suppressing deformation in the X-axis direction and the Z-axis direction. Can be made. The configuration of the second spring portion 24 is provided symmetrically with the first spring portion 22 with respect to the Y axis that intersects the center C of the outer mass portion 14, and is composed of a pair of second spring portions 24a and 24b. ing. By forming each of the second spring portions 24a and 24b in such a shape, the second spring portion 24 can be smoothly expanded and contracted in the Y-axis direction, which is the detection direction, while suppressing deformation in the X-axis direction and the Z-axis direction. Can be made.

  The driving unit 70 has a function of vibrating the outer mass unit 14 at a predetermined frequency in the X-axis direction. That is, the drive unit 70 is vibrated so as to repeat the state in which the outer mass unit 14 is displaced in the + X-axis direction and the state in which the outer mass unit 14 is displaced in the −X-axis direction. The driving unit 70 shown in FIG. 2 includes a driving electrode and a fixed electrode (not shown). One driving unit 70 is provided on a side surface intersecting the Y axis, and is driven by an electrostatic force between the driving electrode and the fixed electrode, for example. In addition, as long as the outer mass portion 14 can be vibrated in the X direction, a more stable driving motion can be achieved by providing the outer mass portion 14 on both side surfaces intersecting the Y axis. The fixed electrode has a pair of comb-like electrode pieces arranged to face each other in the X-axis direction via the drive electrode. The drive unit 70 having such a configuration generates an electrostatic force between each drive electrode and each electrode piece by applying a voltage to the electrode piece by a power source (not shown), while expanding and contracting the drive spring unit 60. The outer mass portion 14 is vibrated in the X-axis direction at a predetermined frequency. The driving unit 70 can employ an electrostatic driving method, a piezoelectric driving method, an electromagnetic driving method using a Lorentz force of a magnetic field, or the like.

  The detection unit 30 includes a movable electrode 32 and a fixed electrode 34. A plurality of movable electrodes 32 are provided so that both ends thereof are connected to the inner mass portion 16 along the X-axis direction as a driving direction, and adjacent electrodes are spaced apart from each other by a predetermined distance. The fixed electrode 34 is provided along the X-axis direction, which is the driving direction, in the gap between the movable electrodes 32, and is fixed to an anchor of a lower substrate (not shown). The movable electrode 32 and the fixed electrode 34 are formed in a comb shape that is alternately arranged. The detection unit 30 having the above configuration generates an electrostatic force between each movable electrode 32 and each fixed electrode 34 by applying a voltage to the electrode by a power source (not shown). When the inner mass portion 16 is displaced in the Y-axis direction, the capacitance changes as the movable electrode 32 approaches or separates from the fixed electrode 34. By detecting this change in capacitance, the amount of displacement in the Y-axis direction can be obtained.

  The vibrating body 40 is provided in the inner mass portion 16, the fixed end 42 side is connected to the inner mass portion 16, and the free end 44 side is extended along the X-axis direction. The vibrating body 40 has a structure (cantilever structure) in which the fixed end 42 side is supported by the inner mass portion 16 and the free end 44 side is cantilevered so that it can move up and down in the Z-axis direction. Since the free end 44 side of the vibrating body 40 extends in the drive direction A, when the drive mass is vibrated in the drive direction A of the outer mass portion 14, the free end 44 can be vibrated in the ± Z-axis direction. The vibrating body 40 is disposed at the center of the inner mass portion 16 so as to be sandwiched between the two detection portions 30. With such a configuration, stable vibration can be maintained.

  FIG. 3 is an explanatory diagram of modifications 1 to 4 of the vibrating body. The vibrating body has a structure that is cantilevered by the inner mass portion, and is formed into the shapes of the following modifications 1 to 4 as long as the vibrating body has a shape that can vibrate in the Z-axis direction along with driving vibration by the driving portion. You can also (1) and (2) are plan views of the vibrating bodies 40a and 40b, both of which connect the fixed end 42 side and the inner mass portion 16 via support portions 46a and 46b. The support portions 46a and 46b are formed on the narrower arm than the vibrating body. An opening 47 is provided between the fixed end 42 and the inner mass portion 16. Such a vibrating body 40a, 40b can have a structure in which the rigidity is reduced by the support portions 46a, 46b and the free end 44 is easily vibrated. (3) is a cross-sectional view of the vibrating body 40c, in which a thin portion 48 is formed on the fixed end 42 side. Such a vibrating body 40c can have a structure in which rigidity is reduced by the thin portion 48 and the free end 44 is easily vibrated. (4) is a plan view of the vibrating body 40d, in which the free end 44a is wider than the fixed end 42a in a plan view with the Z axis as a normal line, or the free end 44a is wider than the fixed end 42a in a sectional view. It is formed into a thick hammerhead mold. Such a vibrating body 40d can make the mass of the free end 44a larger than the fixed end 42a (a weight portion can be formed), and can be structured to easily vibrate in the Z-axis direction with respect to driving. When the vibrating body is divided by the center line of the entire length in the extending direction of the vibrating bodies 40a and 40b, the fixed end side (one end side) indicates a region from the center line to the fixed end, and the free end side (others) (End side) refers to the area from the center line to the tip.

  The gyro sensor of the present invention unifies the drive unit that vibrates the vibrating body to reduce the size of the entire sensor. In order to detect the angular velocity at a constant vibration frequency, it is necessary to vibrate the vibrating body at the same frequency as the drive resonance frequency of the drive vibration by the drive unit. The vibrating body 40 is designed in advance to have a shape that oscillates at the same frequency as the drive resonance frequency, but it may be difficult to form the same at the same frequency due to manufacturing errors or the like. Therefore, the vibrating body 40 of the embodiment is provided with a frequency adjusting unit 80 that can adjust the resonance frequency on the upper surface. 4A and 4B are explanatory diagrams of the frequency adjusting unit, in which FIG. 4A is a perspective view and FIG. 4B is a cross-sectional view taken along line aa in FIG. The frequency adjusting unit 80 can be formed by applying a metal film such as gold or tungsten on the upper surface of the vibrating body 40. Then, as shown in (2), the resonance frequency can be adjusted by irradiating the frequency adjusting unit 80 with laser light to peel off the metal film and reduce the mass of the vibrating body 40. In addition to such a metal film, it is also possible to adjust the resonance frequency by directly irradiating the vibrating body 40 of silicon material with laser light to reduce the mass of the vibrating body 40. With such a frequency adjustment unit 80, the resonance frequency of the vibrating body 40 and the drive resonance frequency of driving the outer mass unit 14 by the drive unit 70 can be matched.

  As shown in FIG. 1, the sensor element 200 capable of detecting rotation acting around the Y axis includes a pair of displacement plates 90 a and 90 b in the first cavity portion 15 of the outer mass portion 14. The displacement plates 90a and 90b are connected to the side surfaces of the outer mass portion 14 that are orthogonal to the X-axis direction by the rotation shafts 92a and 92b. The rotating shafts 92a and 92b are formed at positions shifted from the centers of gravity of the displacement plates 90a and 90b. The rotation shafts 92a and 92b are both provided with the rotation direction along the X-axis direction. When the displacement is applied, the rotation shafts 92a and 92b are torsionally deformed about the axis to rotate the displacement plates 90a and 90b in the Z-axis direction. The displacement plates 90a and 90b are attached so that the rotation directions due to gravity (displacement in the Z-axis direction) rotate in opposite directions with respect to the rotation shafts 92a and 92b. In other words, the direction of displacement of the rotation shafts 92a, 92b from the center of gravity of the displacement plates 90a, 90b and the direction of displacement of the rotation shafts 92a, 92b from the center of gravity of the displacement plates 90a, 90b are opposite to each other. I can say that. A lower electrode (not shown) is provided at a position facing the displacement plates 90a and 90b at a predetermined interval.

As shown in FIG. 1, the sensor element 300 capable of detecting rotation acting around the Z-axis includes an inner mass portion 116, a spring portion 120, and a detection portion 130 as a second detection portion in the outer mass portion 14. ing.
The inner mass portion 116 is provided in the first cavity 15 of the outer mass portion 14, and the outer periphery is surrounded by the outer mass portion 14. The inner mass portion 116 is a substantially rectangular frame in plan view with the Z axis as a normal line, and the side surface intersecting the Y axis is connected to the outer mass portion 14 via the spring portion 120.

  The spring part 120 is composed of first and second spring parts 122 and 124. The first spring portion 122 includes a pair of first spring portions 122a and 122b, and each first spring portion 122a and 122b has a shape extending in the Y-axis direction while reciprocating in the X-axis direction. . The first spring portions 122a and 122b are provided symmetrically with respect to the X axis that intersects the center C ′ of the outer mass portion 14 in plan view with the Z axis as a normal line. By forming each first spring part 122a, 122b in such a shape, the first spring part 122 is smoothly expanded and contracted in the Y-axis direction which is the detection direction while suppressing deformation in the X-axis direction and the Z-axis direction. Can be made. The configuration of the second spring portion 124 is provided symmetrically with the first spring portion 122 with respect to the Y axis that intersects the center C ′ of the outer mass portion 14, and includes a pair of second spring portions 124a and 124b. Has been. By forming each of the second spring portions 124a and 124b in such a shape, the second spring portion 124 can be smoothly expanded and contracted in the Y-axis direction as the detection direction while suppressing deformation in the X-axis direction and the Z-axis direction. Can be made.

  Similar to the detection unit 30 of the sensor element 100, the detection unit 130 includes a movable electrode 132 and a fixed electrode 134. A plurality of movable electrodes 132 are provided so that both ends thereof are connected to the inner mass portion 116 along the X-axis direction as a driving direction, and adjacent electrodes are spaced apart from each other by a predetermined distance. The fixed electrode 134 is provided along the X-axis direction, which is the driving direction, in the gap between the movable electrodes 132, and is fixed to an anchor of a lower substrate (not shown). The movable electrode 132 and the fixed electrode 134 are formed in a comb shape that is alternately arranged.

  The gyro sensor 10 of the present invention includes two vibration bodies on the vibration system structure 121. Specifically, a first vibration system structure 112 having sensor elements 100, 200, and 300 along a sensor driving direction (X-axis direction) and a second vibration system structure having sensor elements 100, 200, and 300 are provided. 212. Here, the first vibrating body 40a and the second vibrating body 40b of the sensor element 100 are arranged so that the vibration directions are the same. Specifically, the free end of the first vibrating body 40a and the free end of the second vibrating body 40b are arranged to face each other. Or you may arrange | position so that the free end of the 1st vibrating body 40a and the free end of the 2nd vibrating body 40b may mutually space apart.

  The first and second vibration system structures 112 and 212 have at least the sensor element 100 as a basic configuration, and include either one of the sensor elements 200 and 300 that can detect rotation acting around the Y axis and the Z axis. It can also be configured.

  The vibration system structure 120 is composed of silicon as a main material, and each part is integrally formed by processing a silicon substrate (silicon wafer) into a desired outer shape using a thin film forming technique and various processing techniques. Is formed.

  A third drive spring portion (connection spring) 66 is formed between the first and second vibration system structures 112 and 212. The third drive spring portion 66 includes a pair of third drive spring portions 66a and 66b, and each third drive spring portion 66a and 66b has a shape extending in the X-axis direction while reciprocating in the Y-axis direction. There is no. The third drive spring portions 66a and 66b are symmetrical with respect to the X axis that intersects the center C of the first vibration system structure 112 and the second vibration system structure 212 in the XY plan view with the Z axis as a normal line. Provided. By making each of the third drive spring portions 66a and 66b have such a shape, the first drive spring portion 62 and the second drive spring portion 64 are prevented from being deformed in the Y-axis direction and the Z-axis direction, and the X-axis. Can expand and contract smoothly in the direction. First and second drive spring portions 62 and 64 are provided at four corners of the first and second vibration system structures 112 and 212.

  The drive unit 72 of the gyro sensor 10 has the same basic configuration as the drive unit 70 shown in FIG. A pair of drive parts 72a and 72b is attached to the side surface that intersects the X-axis direction of the first vibration system structure 112, and a pair of drive parts 72c and 72d is attached to the side surface that intersects the X-axis direction of the second vibration system structure 212. It is attached. The drive units 72a and 72b of the first vibration system structure 112 and the drive units 72c and 72d of the second vibration system structure 212 apply an alternating voltage whose phase is shifted by 180 degrees, thereby applying each drive electrode and each electrode. An electrostatic force is generated between each piece. When the first to third drive springs 62, 64, 66 expand and contract in the X-axis direction, the first vibration system structure 112 and the second vibration system structure 212 are in opposite phases and at a predetermined frequency in the X-axis direction. Can be vibrated. Note that only one of the drive units 72a and 72b may be formed. The same applies to the drive units 72c and 72d.

The operation of the gyro sensor 10 of the present invention having the above configuration will be described below.
In general, the Coriolis force can be expressed as Equation 1.

  FIGS. 5A and 5B are explanatory views for detecting rotation acting around the X axis, wherein FIG. 5A is a perspective view and FIG. 5B is a cross-sectional view taken along line bb in FIG. The inner mass portion 16 in the outer mass portion is driven in the driving direction A by the driving portion. Along with this driving vibration, the vibrating body 40 vibrates (v) in the Z-axis direction. When an angular velocity (Ωx) is input around the axis in the X-axis direction that is the driving direction, the Coriolis force acts in the ± Y-axis direction. When the Coriolis force acts in the Y-axis direction, the capacitance of the detection unit 30 changes as the movable electrode 32 approaches or moves away from the fixed electrode 34. By detecting this change in capacitance and obtaining the Coriolis force in the Y-axis direction, rotation acting around the X-axis can be detected.

  FIGS. 6A and 6B are explanatory diagrams for detecting rotation acting around the Y-axis. FIG. 6A is a perspective view, and FIG. 6B is a cc cross-sectional view of FIG. The outer mass portion 14 is driven in the driving direction A by the driving portion. When the angular velocity around the axis (Ωy) in the Y-axis direction is input, the Coriolis force acts in the ± Z-axis direction. When the Coriolis force acts in the Z-axis direction, the capacitance of the displacement plates 90a and 90b changes as they approach or separate from the lower electrode. By detecting this change in capacitance and obtaining the Coriolis force in the Z-axis direction, it is possible to detect rotation acting around the Y-axis.

  FIG. 7 is an explanatory diagram for detecting rotation acting around the Z axis. The inner mass portion 116 in the outer mass portion is driven in the driving direction A by the driving portion. When angular velocity (Ωz) is input around the Z-axis direction, the Coriolis force acts in the ± Y-axis direction. When the Coriolis force acts in the Y-axis direction, the detection unit 130 changes its capacitance as the movable electrode 132 approaches or moves away from the fixed electrode 134. By detecting this change in capacitance and obtaining the Coriolis force in the Y-axis direction, it is possible to detect rotation acting around the Z-axis.

  Note that in the sensor element 100 of FIG. 1, when the rotation acting around the X axis is detected, the rotation acting around the Z axis may also be detected. The gyro sensor 10 of the present invention is configured such that the first vibrating body 40a and the second vibrating body 40b have the same vibration direction in the Z direction by making the extending direction of the vibrating body opposite. According to such a configuration, the displacement of the inner mass portion 16 when subjected to rotation around the Z axis is opposite to each other in the Y axis direction on the first vibration system structure 112 side and the second vibration system structure 212 side. Only the displacement around the X-axis can be detected by removing the sum of the output signals from both.

According to such a gyro sensor 10, it is possible to reduce the size of the entire sensor by using a common drive unit for multi-axis detection.
Further, in the sensor element 100 of FIG. 1, the Y-axis acceleration component may be detected. When it is desired to eliminate the Y-axis acceleration component, the extending directions of the vibrating bodies of the first vibrating body 40a and the second vibrating body 40b are made the same, and the Z-axis direction of the first vibrating body 40a and the second vibrating body 40b is set. By detecting the difference between the output signals from both the first vibration system structure 112 side and the second vibration system structure 212 side by reversing the vibration directions, detection of the Y-axis acceleration can be eliminated.

  FIG. 8 is an explanatory diagram of an integrated circuit of the gyro sensor. As shown in the figure, the gyro sensor 10 has an integrated circuit (IC) 52 electrically connected to the drive unit 70. The gyro sensor 10 of the present invention can detect a plurality of angular velocities with the sensor elements 100, 200, and 300 by driving and vibrating the outer mass portion 14 with one drive portion 70. The drive unit 70 can be driven by the integrated circuit 52 to obtain the desired drive amplitude with the same drive resonance frequency for each axis.

  FIG. 9 is an explanatory diagram of a mobile phone to which an electronic device including the gyro sensor of the present invention is applied. As illustrated, the mobile phone 500 includes a plurality of operation buttons 502, an earpiece 504, and a transmission port 506, and a display unit 508 is disposed between the operation buttons 502 and the earpiece 504. Such a cellular phone 500 has a built-in gyro sensor 10 that functions as an angular velocity detection means.

10 ......... Gyro sensor, 12, 121 ......... Vibrating structure, 14 ......... Outer mass portion, 15 ......... First cavity portion, 16, 116 ......... Inner mass portion, 17 ......... No. 2 hollow portions, 20, 120 ......... spring portions, 22, 122 ......... first spring portions, 24, 124 ......... second spring portions, 30, 130 ......... detection portions, 32, 132 ......... Movable electrode, 34, 134 ......... Fixed electrode, 40 ......... Vibrating body, 42 ......... Fixed end, 44 ......... Free end, 47 ......... Opening, 48 ......... Thin part, 50 ......... Fixed portion, 52... Integrated circuit (IC), 60... Drive spring portion, 62... First drive spring portion, 64... Second drive spring portion, 66. , 70, 72... Drive section, 80... Frequency adjustment section, 90 a, 90 b ...... displacement plate, 92 a, 92 b,. 00, 300 ......... sensor element, 112 ......... first vibration system structure, 212 ......... second vibration system structure, 500 ......... mobile phone, 502 ...... operation buttons, 504 .... Mouth, 506 ... Transmission port, 508 ... Display section.

Claims (13)

An outer mass having a first cavity,
An inner mass provided in the first cavity of the outer mass and having a second cavity;
A drive unit for driving the outer mass part in the direction of the first axis integrally with the inner mass part;
A spring portion connected between the outer mass portion and the inner mass portion and displaceable in a direction of a second axis perpendicular to the direction of the first axis;
A first detector that is provided in the second cavity of the inner mass portion and detects an angular velocity around the axis of the first axis;
A vibrator provided in the second cavity of the inner mass portion;
Comprising a vibration system structure with
The vibrating body is a cantilever support structure in which one end is connected to the inner wall of the second cavity portion of the inner mass portion, the other end is lifted in the direction of the first axis, and the other end is floated. The gyro sensor is characterized in that the vibrator can vibrate in a third axis direction perpendicular to the first axis and the second axis in accordance with the driving vibration in the direction.   The gyro sensor according to claim 1, wherein the vibrating body is provided with a frequency adjusting unit.   The gyro sensor according to claim 2, wherein the frequency adjustment unit is provided on the other end side of the vibrating body.   The gyro sensor according to claim 2 or 3, wherein the frequency adjusting unit is provided with a metal film.   5. The gyro sensor according to claim 1, wherein the vibration body has a rigidity on the one end side smaller than a rigidity on the other end side.   The gyro sensor according to claim 1, wherein a weight portion is provided on the other end side of the vibrating body.   The gyro sensor according to claim 1, wherein a groove or a through hole is provided on the one end side of the vibrating body. The outer mass portion is disposed above the substrate,
The said 1st detection part contains the fixed electrode provided in the said board | substrate, and the movable electrode provided in the said inner mass part, The one of Claim 1 thru | or 7 characterized by the above-mentioned. Gyro sensor.   The vibration system structures are arranged side by side in the direction of the first axis, are connected by a spring that connects the vibration system structures, and vibrates the vibration system structures in opposite directions. Item 10. The gyro sensor according to any one of Items 1 to 8. Reversing the extending direction of the vibrating body of one vibrating system structure and the extending direction of the vibrating body of the other vibrating system structure;
The gyro sensor according to claim 9, wherein a sum of an output signal of one of the vibration system structures and an output signal of the other vibration system structure is obtained. The extension direction of the vibration body of one vibration system structure and the extension direction of the vibration body of the other vibration system structure are the same,
The gyro sensor according to claim 9, wherein a difference between an output signal of one of the vibration system structures and an output vibration of the other vibration system structure is taken.   12. The vibration system structure includes a second detection unit that detects at least one of angular velocities around the second axis and the third axis. The gyro sensor according to item 1.   An electronic apparatus comprising the gyro sensor according to claim 1.

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