JP5966460B2 - Gyro sensor and electronics - Google Patents

Description

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

Conventionally, the gyro element of patent document 1 is known as a vibration piece for detecting angular velocity.
The gyro element of Patent Document 1 includes a base, first and second detection vibrating arms extending from the base to both sides in the Y-axis direction, and first and second connecting arms extending from the base to both sides in the X-axis direction. And first and second drive vibrating arms extending in the Y-axis direction from the tip of the first connecting arm to both sides, and third and third extending from the tip of the second connecting arm to the both sides in the Y-axis direction. 4 drive vibration arms. Further, drive electrodes are formed on the first to fourth drive vibrating arms, and detection electrodes are formed on the first and second detection vibrating arms.

  Such a gyro element detects an angular velocity as follows. First, the first to fourth drive vibrating arms are vibrated so that the first and second drive vibrating arms and the third and fourth drive vibrating arms are plane-symmetric with respect to the YZ plane. When an angular velocity is applied around the Z axis in this state, a Coriolis force acts on the gyro element, and detection vibration in the X axis direction is excited on the first and second detection vibrating arms. Then, the detection electrode detects the distortion of the first and second detection vibrating arms caused by this vibration, whereby the angular velocity around the Z axis can be obtained.

  However, the gyro element of Patent Document 1 can only detect the angular velocity around the Z axis. That is, the angular velocity around the X axis and the angular velocity around the Y axis cannot be detected. Therefore, for example, when it is desired to detect the angular velocities generated around the X-axis and the Y-axis, it is necessary to arrange the gyro elements in a vertical position, which increases the thickness of the sensor device. If it is desired to detect angular velocities for a plurality of axes, it is necessary to arrange a plurality of gyro elements. Therefore, there is a problem that the apparatus becomes large.

JP 2006-201011 A

  An object of the present invention is to provide a gyro sensor that can detect angular velocities around two axes intersecting each other, and to provide a highly reliable electronic device including the gyro sensor. .

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 forms or application examples.
[Application Example 1]
The gyro sensor of the present invention has three axes intersecting each other as a first axis, a second axis, and a third axis.
The base,
A first connecting arm and a second connecting arm extending oppositely from each other along the first axis from the base;
A first drive vibrating arm extending from the first connecting arm along the second axis;
A second drive vibrating arm extending from the second connecting arm along the second axis;
A first detection vibrating arm and a second detection vibrating arm extending opposite to each other along the second axis from the base,
Wherein each of the first drive vibrating arm and the second driving vibration arms, seen including a vibration component of the first axis and the direction of the third axis,
In the state where the first drive vibrating arm and the second drive vibrating arm are vibrating, the vibrations of the first detection vibrating arm and the second detection vibrating arm excited by the application of an angular velocity around the second axis. The pattern and the vibration pattern of the first detection vibration arm and the second detection vibration arm excited by applying an angular velocity around the third axis are different from each other,
When an angular velocity about the second axis is applied, the first detection vibrating arm and the second detection vibrating arm vibrate in the same direction with respect to the first axis;
When an angular velocity around the third axis is applied, the first detection vibrating arm and the second detection vibrating arm vibrate in opposite directions with respect to the first axis;
One of the angular velocity around the second axis and the angular velocity around the third axis is detected by adding the output signal from the first detection vibrating arm and the output signal from the second detection vibrating arm, and the first The other of the angular velocity around the second axis and the angular velocity around the third axis is detected by subtracting the output signal from the first detection vibrating arm and the output signal from the second detection vibrating arm. .
Accordingly, it is possible to provide a gyro sensor that can detect angular velocities around the two axes that intersect each other.

[Application Example 2]
In the gyro sensor of the present invention, it is preferable that the first drive vibrating arm and the second drive vibrating arm have the same vibration component of the third axis during drive vibration.
Thereby, the first and second drive vibrating arms can be vibrated with good balance.
[Application Example 3]
In the gyro sensor of the present invention, it is preferable that the first drive vibration arm and the second drive vibration arm have opposite vibration components of the first axis during drive vibration.
Thereby, the first and second drive vibrating arms can be vibrated with good balance.

[Application Example 4]
In the gyro sensor of the present invention, each of the first drive vibrating arm and the second drive vibrating arm has a cross section in the second axial direction with respect to a center line in the first axial direction and a center line in the third axial direction. It is preferable to include a portion having an asymmetric shape.
Accordingly, the first and second drive vibrating arms are more reliably arms that include vibration components in the directions of the first axis and the third axis.

[Application Example 5]
In the gyro sensor of the present invention, each of the first drive vibrating arm and the second drive vibrating arm is:
A first surface and a second surface that are in reverse relation to each other;
A first groove provided in the first surface;
A second groove provided on the second surface,
It is preferable that the first groove and the second groove are arranged in the direction of the first axis in a plan view from the normal direction of the first surface.
Thereby, the shape of the first and second drive vibrating arms can be simplified.

[Application Example 6]
In the gyro sensor of the present invention, each of the first drive vibrating arm and the second drive vibrating arm is:
A first surface and a second surface that are in reverse relation to each other;
A first side surface and a second side surface connecting the first surface and the second surface;
It is preferable that at least one of the first side surface and the second side surface includes a stepped portion.
Thereby, the shape of the first and second drive vibrating arms can be simplified.

[Application Example 7]
In the gyro sensor of the present invention, a third drive vibrating arm extending in a direction opposite to a direction in which the first drive vibrating arm extends,
It is preferable to include a fourth drive vibrating arm that extends in a direction opposite to the direction in which the second drive vibrating arm extends.
As a result, the number of drive vibrating arms is increased, and the angular velocity detection accuracy is improved. In addition, the first to fourth drive vibrating arms can be vibrated with good balance.

[Application Example 8 ]
In the gyro sensor of the present invention, the first detection vibrating arm and the second detection vibrating arm are made of a piezoelectric material,
It is preferable that the first detection vibrating arm and the second detection vibrating arm have substantially rectangular cross-sectional shapes, and electrodes are provided on each surface.
Thereby, the output signals of the first detection vibrating arm and the second detection vibrating arm can be extracted with a simple configuration.

[Application Example 9 ]
In the gyro sensor of the present invention, the first detection vibrating arm and the second detection vibrating arm are:
Composed of piezoelectric material,
The first detection vibrating arm and the second detection vibrating arm include a pair of main surfaces that are in a front-back relationship with each other and a pair of side surfaces that connect the main surfaces, and at least one of the pair of main surfaces has a groove. It is preferable that an electrode is provided on the inner wall of the groove and on the side surface opposite to the inner wall.
Thereby, the detection sensitivity of angular velocity improves.

[Application Example 10 ]
In the gyro sensor of the present invention, the first detection vibrating arm and the second detection vibrating arm are preferably provided with a piezoelectric element having a piezoelectric film disposed between the first electrode and the second electrode on a main surface. .
Thereby, the output signals of the first detection vibrating arm and the second detection vibrating arm can be extracted with a simple configuration.

[Application Example 11 ]
In the gyro sensor of the present invention, it is preferable that strain detection means is provided on at least one of the first connecting arm and the second connecting arm.
Thereby, the angular velocity around the first axis can be detected.
[Application Example 12 ]
An electronic apparatus according to the present invention includes the gyro sensor according to the present invention.
Thereby, an electronic device having excellent reliability can be obtained.

It is a top view which shows 1st Embodiment of the gyro sensor of this invention. It is the sectional view on the AA line in FIG. 1, and the BB sectional drawing. It is CC sectional view taken on the line in FIG. It is sectional drawing which shows the modification of the drive vibration arm shown in FIG. It is sectional drawing which shows the modification of the drive vibration arm shown in FIG. It is a top view explaining the drive of the gyro sensor shown in FIG. It is a top view which shows the vibration of a gyro sensor when the angular velocity around Z-axis is added. It is a top view which shows the vibration of a gyro sensor when the angular velocity around a Y-axis is added. It is a top view which shows the gyro sensor concerning 2nd Embodiment of this invention. It is the DD sectional view taken on the line in FIG. 9, and the EE sectional view taken on the line. It is a top view which shows the gyro sensor concerning 3rd Embodiment of this invention. It is the FF sectional view taken on the line in FIG. 11, and the GG sectional view. It is an electronic device (notebook type personal computer) provided with the gyro sensor of this invention. It is an electronic device (cellular phone) provided with the gyro sensor of the present invention. It is an electronic device (digital still camera) provided with the gyro sensor of the present invention. It is sectional drawing which shows the modification of the drive vibration arm shown in FIG.

Hereinafter, a gyro sensor and an electronic device according to the present invention will be described in detail based on embodiments shown in the accompanying drawings.
<First Embodiment>
First, a first embodiment of the gyro sensor of the present invention will be described.
1 is a plan view showing a first embodiment of the gyro sensor of the present invention, FIG. 2 is a cross-sectional view taken along line AA and BB in FIG. 1, and FIG. 3 is a cross-sectional view taken along line C-B in FIG. 4 is a cross-sectional view showing a modification of the drive vibrating arm shown in FIG. 3, FIG. 6 is a plan view for explaining the driving of the gyro sensor shown in FIG. 1, and FIG. FIG. 8 is a plan view showing the vibration of the gyro sensor when an angular velocity around the Z axis is applied. FIG. 8 is a plan view showing the vibration of the gyro sensor when an angular velocity around the Y axis is applied.

  In the following, as shown in FIG. 1, the three axes orthogonal to each other are referred to as an X axis (first axis), a Y axis (second axis), and a Z axis (third axis). A direction parallel to the X axis is also referred to as an “X axis direction”, a direction parallel to the Y axis is also referred to as a “Y axis direction”, and a direction parallel to the Z axis is also referred to as a “Z axis direction”. A plane defined by the X axis and the Y axis is also referred to as an “XY plane”, a plane defined by the Y axis and the Z axis is also referred to as a “YZ plane”, and a plane defined by the Z axis and the X axis is represented by “ It is also called “XZ plane”.

A gyro sensor 2 shown in FIG. 1 is a gyro sensor that can detect an angular velocity ωz around the Z axis and an angular velocity ωy around the Y axis. The gyro sensor 2 includes a vibrating piece 3 and a plurality of electrodes formed on the vibrating piece 3.
The vibrating piece 3 is made of a piezoelectric material. Examples of the piezoelectric material include crystal, lithium tantalate, lithium niobate, lithium borate, and barium titanate. In particular, the piezoelectric material constituting the resonator element 3 is preferably quartz. If the resonator element 3 is made of quartz, the vibration characteristics (particularly frequency temperature characteristics) of the resonator element 3 can be made excellent. Further, the resonator element 3 can be formed with high dimensional accuracy by etching.
Such a resonator element 3 has an extension in the XY plane, has a thickness in the Z-axis direction, a base 41, first and second detection vibrating arms 42 and 43, and first and second connecting arms 44. , 45 and first, second, third, and fourth drive vibrating arms 46, 47, 48, 49.

  The base 41 is located at the center of the resonator element 3. Further, the first detection vibrating arm 42 and the second detection vibrating arm 43 extend in the Y axis direction opposite to each other from the base 41. The first connecting arm 44 and the second connecting arm 45 extend from the base portion 41 in the X-axis direction opposite to each other. Further, the first drive vibrating arm 46 and the third drive vibrating arm 48 extend in the Y-axis direction opposite to each other from the distal end portion of the first connecting arm 44. The second and fourth drive vibrating arms 47 and 49 extend in the Y-axis direction opposite to each other from the distal end portion of the second connecting arm 45.

  In the configuration shown in the figure, the widths of the first connecting arm 44 and the second connecting arm 45 are narrower than the width of the base 41, but may be formed integrally with the base 41. The first and third drive vibrating arms 46 and 48 may extend from the middle of the extending direction of the first connecting arm 44. Similarly, the second and fourth drive vibrating arms 47 and 49 You may extend from the middle of the extension direction of the 2 connection arms 45. FIG.

The first and second detection vibrating arms 42 and 43 are provided symmetrically with respect to the XZ plane intersecting with the center of gravity (center) G. The first and second detection vibrating arms 42 and 43 have a substantially rectangular cross-sectional shape.
Further, as shown in FIG. 2, first detection signal electrodes (electrodes) 710 a are formed on the upper and lower surfaces of the first detection vibrating arm 42, and the second detection signal is formed on the upper and lower surfaces of the second detection vibrating arm 43. An electrode (electrode) 710b is formed.
Further, first detection ground electrodes (electrodes) 720 a are formed on both side surfaces of the first detection vibrating arm 42, and second detection ground electrodes (electrodes) 720 b are formed on both side surfaces of the second detection vibration arm 43. Yes. Such first and second detection ground electrodes 720a and 720b have a potential to be ground with respect to the first and second detection signal electrodes 710a and 710b.

  In the configuration shown in the figure, the first detection vibrating arm 42 and the second detection vibrating arm 43 have a rectangular cross-sectional shape. However, the first detection vibrating arm 42 and the second detection vibrating arm 42, 43 are formed on at least one of the upper and lower surfaces. A groove may be provided. In that case, it is desirable to form the first detection signal electrode 710a (second detection signal electrode 710b) along the inner wall of the groove. By adopting such a configuration, the distance between the first detection signal electrode 710a (second detection signal electrode 710b) and the first detection ground electrode 720a (second detection ground electrode 720b) formed on the side surface is reduced, and the electric field is reduced. The efficiency is improved and a large amount of charge can be generated between the electrodes with a small amount of strain, which contributes to high sensitivity.

By forming the first and second detection signal electrodes 710a and 710b and the first and second detection ground electrodes 720a and 720b in such an arrangement, the detection vibration generated in the first detection vibration arm 42 is detected by the first detection. It appears as a charge between the signal electrode 710a and the first detection ground electrode 720a, and the charge can be taken out as a signal (output signal). The detection vibration generated in the second detection vibration arm 43 is the second detection signal electrode. It appears as a charge between 710b and the second detection ground electrode 720b, and the charge can be taken out as a signal.
The first drive vibrating arm 46 has a distal end portion 46a located on the distal end side and a proximal end portion (asymmetrical portion) 46b located on the proximal end side. The distal end portion 46a has a substantially rectangular cross-sectional shape.

  As shown in FIG. 3, the base end portion 46 b has an asymmetric cross-sectional shape (Y-axis direction) with respect to both the center line L ′ in the X-axis direction and the center line L ″ in the Z-axis direction of the first drive vibrating arm 46. By forming the base end portion 46b in such an asymmetric shape, the first drive vibrating arm 46 has both components in the X-axis direction and the Z-axis direction, as will be described later. Bending vibration (hereinafter, also simply referred to as “oblique vibration” for convenience of explanation) can be performed in the direction, in other words, the direction inclined with respect to both the X axis and the Z axis.

Specifically, the base end portion 46b of the first drive vibrating arm 46 is opposed to the Z-axis direction and includes an upper surface (first surface) 461 and a lower surface (second surface) 462 configured by an XY plane, and an upper surface. 461 and a lower surface 462 are connected to each other. The base end portion 46 b includes a first step 465 provided between the upper surface 461 and the side surface (first side surface) 463 and a second step provided between the lower surface 462 and the side surface (second side surface) 464. Part 466.
The first step portion 465 is formed on the first detection vibrating arm 42 side with respect to the center line L ′. The first step portion 465 is configured by the YZ plane, and the first step surface 465a connected to the upper surface 461 and the second step connected to the first step surface 465a and the side surface 463 by the XY plane. And a step surface 465b.

On the other hand, the second step portion 466 is formed on the opposite side (the other side) to the first detection vibrating arm 42 with respect to the center line L ′. The second step portion 466 is configured by the YZ plane, and is configured by the third step surface 466a connected to the lower surface 462 and the fourth step surface configured by the XY plane and connected to the third step surface 466a and the side surface 464. A step surface 466b.
By adopting such a shape, the first drive vibration arm 46 can be a drive arm having an oblique vibration component.

Here, in other words, the shape of the base end portion 46b can be expressed as follows. That is, as shown in FIG. 3, the base end portion 46b extends to the X-axis direction (+) side, and extends from the tip of the first side L1 to the Z-axis direction (−) side. The second side L2 that protrudes, the third side L3 that extends from the tip of the second side L2 to the X-axis direction (+) side, and the tip that extends from the tip of the third side L3 to the Z-axis direction (−) side The fourth side L4, the fifth side L5 extending from the tip of the fourth side L4 to the X-axis direction (−) side, and the sixth side extending from the tip of the fifth side L5 to the Z-axis direction (+) side A side L6, a seventh side L7 extending from the tip of the sixth side L6 to the X-axis direction (−) side, and a tip of the seventh side L7 extending to the Z-axis direction (+) side, the tip being the first It has a cross-sectional shape in which a contour is formed by an eighth side L8 connected to the base end of the side L1.
The first step portion 465 and the second step portion 466 are formed rotationally symmetric with respect to the central axis O of the first drive vibrating arm 46. Thereby, the mass of one side and the other side of the center line L ′ of the first drive vibrating arm 46 can be made substantially equal, and the first drive vibrating arm 46 has a mass balanced shape.

Here, in the first drive vibrating arm 46 of the present embodiment, the second step surface 465b of the first step portion 465 is at the same position in the Z-axis direction with respect to the fourth step surface 466b of the second step portion 466. Is provided.
The first step surface 465a of the first step portion 465 is provided to be separated from the third step surface 466a of the second step portion 466 on the first detection vibrating arm 42 side in the X-axis direction.

  With such a configuration, the mechanical strength of the region S1 sandwiched between the first step portion 465 and the second step portion 466 can be sufficiently ensured. Therefore, the first drive vibrating arm 46 can be stably vibrated obliquely. In addition, by ensuring the strength, the first drive vibrating arm 46 can be effectively prevented from being twisted, and unnecessary vibration can be effectively prevented.

  A pair of drive signal electrodes 730 and a pair of drive ground electrodes 740 are formed on the first drive vibrating arm 46 as described above. Specifically, one of the pair of drive signal electrodes 730 is formed on the upper surface 461, and the other is formed on the lower surface 462. One of the pair of driving ground electrodes 740 is formed across the first step surface 465a, the second step surface 465b, and the side surface 463, and the other is the side surface 464, the fourth step surface 466b, and the third step surface. It is formed across 466a. The drive ground electrode 740 has a potential that serves as a ground with respect to the drive signal electrode 730.

  When the drive signal electrode 730 and the drive ground electrode 740 are formed in such an arrangement, the drive signal formed between the drive signal electrode 730 and the drive ground electrode 740 is applied to the drive formed on the first drive vibration arm 46. An electric field can be generated between the signal electrode 730 and the drive ground electrode 740 to vibrate the first drive vibrating arm 46. This also applies to the second, third, and fourth drive vibrating arms 47, 48, and 49 described below.

  The shape of the first drive vibrating arm 46 has been described above. However, for example, the shape shown in FIG. 4 may be used. That is, the base end portion 46 b is formed in the upper surface 461, the lower surface 462, a pair of side surfaces 463 and 464 that connect the upper surface 461 and the lower surface 462, the first groove 467 formed in the upper surface 461, and the lower surface 462. A second groove 468. The first and second grooves 467 and 468 are formed so as to be shifted in the X-axis direction, and have portions that overlap each other in the X-axis direction. That is, the base end portion 46b has a substantially “S” -shaped cross-sectional shape. With such a shape, the first drive vibrating arm 46 can be a vibrating arm having an oblique vibration component with a simple configuration.

  In addition, the shape shown in FIG. The shapes shown in FIGS. 5A and 5B have the same configuration except that the shapes of the first step portion 465 and the second step portion 466 (width and thickness aspects are not different) from the present embodiment. Further, in FIG. 5, for convenience of explanation, 0%, 50%, and 100% of the width of the first drive vibrating arm 46 and 0%, 50%, and 100% of the thickness of the first drive vibrating arm 46 are shown. Auxiliary lines are displayed at each location. In FIG. 5, illustration of various electrodes is omitted for convenience of explanation.

  In the first drive vibrating arm 46 shown in FIG. 5A, the second step surface 465b of the first step portion 465 is on the upper surface 461 side in the Z-axis direction with respect to the fourth step surface 466b of the second step portion 466. Are spaced apart from each other. The first step surface 465a of the first step portion 465 is provided to be separated from the third step surface 466a of the second step portion 466 on the first detection vibrating arm 42 side in the X-axis direction.

In the first drive vibrating arm 46 shown in FIG. 5B, the second step surface 465b of the first step portion 465 is on the lower surface 462 side in the Z-axis direction with respect to the fourth step surface 466b of the second step portion 466. Are spaced apart from each other. The first step surface 465a of the first step portion 465 is provided to be separated from the third step surface 466a of the second step portion 466 on the first detection vibrating arm 42 side in the X-axis direction.
In the first drive vibrating arm 46 shown in FIG. 5C, the second step surface 465b of the first step portion 465 is on the upper surface 461 side in the Z-axis direction with respect to the fourth step surface 466b of the second step portion 466. Are spaced apart from each other. The first step surface 465a of the first step portion 465 is provided at the same position in the X-axis direction with respect to the third step surface 466a of the second step portion 466.

In the first drive vibrating arm 46 shown in FIG. 5D, the second step surface 465b of the first step portion 465 is on the upper surface 461 side in the Z-axis direction with respect to the fourth step surface 466b of the second step portion 466. Are spaced apart from each other. The first step surface 465a of the first step portion 465 is provided on the opposite side to the first detection vibrating arm 42 in the X-axis direction with respect to the third step surface 466a of the second step portion 466. Yes.
As described above, the first drive vibrating arm 46 can be vibrated obliquely with a simple configuration even with the configuration shown in FIGS.

The third drive vibrating arm 48 has the same configuration as the first drive vibrating arm 46 except that it is formed symmetrically with the first drive vibrating arm 46 with respect to the XZ plane intersecting the center of gravity G. Therefore, the description of the configuration of the third drive vibrating arm 48 is omitted.
As shown in FIG. 2B, the third drive vibrating arm 48 is formed with a pair of drive signal electrodes 730 and a pair of drive ground electrodes 740. One of the pair of drive signal electrodes 730 is formed on the upper surface 481, and the other is formed on the lower surface 482. One of the pair of drive ground electrodes 740 is formed across the first step surface 485a, the second step surface 485b, and the side surface 483, and the other is the side surface 484, the fourth step surface 486b, and the third step surface. It is formed across 486a.
The second drive vibration arm 47 has the same configuration as the first drive vibration arm 46 except that it is formed in contrast to the first drive vibration arm 46 with respect to the YZ plane intersecting the center of gravity G. Therefore, the description of the configuration of the second drive vibrating arm 47 is omitted.

As shown in FIG. 2A, the second drive vibrating arm 47 is formed with a pair of drive signal electrodes 730 and a pair of drive ground electrodes 740. One of the pair of drive signal electrodes 730 is formed across the first step surface 475a, the second step surface 475b, and the side surface 473, and the other is formed on the side surface 474, the fourth step surface 476b, and the third step surface 476a. It is formed straddling. One of the pair of drive ground electrodes 740 is formed on the upper surface 471, and the other is formed on the lower surface 472.
The fourth drive vibrating arm 49 has the same configuration as the third drive vibrating arm 48 except that it is formed in contrast to the third drive vibrating arm 48 with respect to the YZ plane intersecting the center of gravity G. Therefore, the description of the configuration of the fourth drive vibrating arm 49 is omitted.

  As shown in FIG. 2A, the fourth drive vibration arm 49 is formed with a pair of drive signal electrodes 730 and a pair of drive ground electrodes 740. One of the pair of drive signal electrodes 730 is formed across the first step surface 495a, the second step surface 495b, and the side surface 493, and the other is formed on the side surface 494, the fourth step surface 496b, and the third step surface 496a. It is formed straddling. One of the pair of drive ground electrodes 740 is formed on the upper surface 491, and the other is formed on the lower surface 492.

The first to fourth drive vibrating arms 46 to 49 have been described above. However, the first to fourth drive vibrating arms 46 to 49 have the same vibration component in the Z-axis direction. The first and third drive vibrating arms 46 and 48 and the second and fourth drive vibrating arms 47 and 49 have the vibration components in the X-axis direction opposite to each other. By making the first to fourth drive vibrating arms 46 to 49 have such a vibration component, the four vibrating arms 46 to 49 can be vibrated with good balance, and vibration leakage can be suppressed. .
In addition, each electrode demonstrated above can each use what formed the gold plating in the base layer which is formed in the surface of the vibration piece 3, and is comprised with chromium, for example. Thereby, the adhesiveness of an electrode and the vibration piece 3 improves, and the reliability of the gyro sensor 2 improves.

  The configuration of the gyro sensor 2 has been described above. The gyro sensor 2 detects the angular velocity ωy around the Y axis and the angular velocity ωz around the Z axis as follows. Hereinafter, although description will be made based on FIGS. 6 to 8, for convenience of explanation, illustration of each electrode is omitted in FIG. 6. 6A is a cross-sectional view corresponding to the cross-sectional view taken along line AA in FIG. 1, and FIG. 6B is a cross-sectional view corresponding to the cross-sectional view taken along line BB in FIG. is there.

  When an alternating voltage is applied between the drive signal electrode 730 and the drive ground electrode 740 in a state where the angular velocity is not applied, as shown in FIG. 6, the first to fourth drive vibrating arms 46 to 49 each have an asymmetric part. Because it is, it vibrates diagonally. Further, this vibration is a plane-symmetric vibration with respect to the YZ plane where the first and third drive vibrating arms 46 and 48 and the second and fourth drive vibrating arms 47 and 49 intersect with the center of gravity G.

  At this time, as described above, the first and third driving vibrating arms 46 and 48 and the second and fourth driving vibrating arms 47 and 49 perform plane-symmetric vibration with respect to the YZ plane passing through the center of gravity G. The vibrations in the X-axis direction of the first to fourth drive vibrating arms 46 to 49 are canceled out. Therefore, the first and second detection vibrating arms 42 and 43 hardly vibrate in the X-axis direction. On the other hand, since the first to fourth drive vibrating arms 46 to 49 vibrate toward the same side in the Z-axis direction, vibrations in the Z-axis direction of the first to fourth drive vibrating arms 46 to 49 are not canceled out. . Therefore, as shown in FIG. 6, the first and second detection vibrating arms 42 and 43 are arranged in the Z-axis direction and the first to first driving arms so as to be balanced with the first to fourth driving vibrating arms 46 to 49. It bends and vibrates in the opposite direction to the four-drive vibrating arms 46-49. Note that the vibration direction of the first to fourth drive vibrating arms 46 to 49 is not limited to the vibration direction illustrated in FIG. 6, and may be, for example, opposite to the vibration direction illustrated in FIG. 6. The vibration direction is appropriately selected depending on the desired frequency and driving means.

  In this state, when an angular velocity ωz around the Z-axis is applied to the gyro sensor 2, a Coriolis force A acts as shown in FIG. 7, and the Coriolis force A is driven to vibrate as indicated by an arrow B (around the Z-axis). Angular velocity detection vibration mode) is excited. At this time, the deformation generated in the first and second detection vibrating arms 42 and 43 is in the opposite direction with respect to the X axis. The detection vibration mode is preferably a frequency within ± 10% of the drive frequency. In addition, regarding the vibration direction of the first and second detection vibrating arms 42 and 43, it can be said that the first and second detection vibrating arms 42 and 43 vibrate in the same rotation direction around the Z axis. This is because the first to fourth drive vibrating arms 46 to 49 vibrate as shown in FIG. 7 due to the action of the Coriolis force A, and the first and second detection vibrating arms 42 and 43 are located on the upper side across the base 41. Since each extends downward, the first detection vibrating arm 42 is deformed corresponding to the first and second drive vibrating arms 46 and 47, and the second detection vibrating arm 43 is third and fourth driven. This is for performing deformation corresponding to the vibrating arms 48 and 49.

  On the other hand, when an angular velocity ωy around the Y axis is applied to the gyro sensor 2, a Coriolis force A acts as shown in FIG. 8, and this Coriolis force A is used as a driving force to vibrate as indicated by an arrow B (Y axis angular velocity detection). Vibration mode) is excited. At this time, the deformation generated in the first and second detection vibrating arms 42 and 43 is in the same direction with respect to the X axis. The detection vibration mode is preferably a frequency within ± 10% of the drive frequency. In addition, regarding the vibration direction of the first and second detection vibrating arms 42 and 43, it can be said that the first and second detection vibrating arms 42 and 43 vibrate in the same direction with respect to the X axis. This is because the first to fourth drive vibrating arms 46 to 49 vibrate as shown in FIG. 8 due to the action of the Coriolis force A, and the first and second detection vibrating arms 42 and 43 are in the same direction with respect to the X axis and the first direction. This is because the Coriolis force in the direction opposite to that of the fourth drive vibrating arms 46 to 49 works, so that the X-axis direction vibrates in the same direction.

In the gyro sensor 2, the angular velocity ωz and the angular velocity are utilized by utilizing the difference in the vibration direction of the detection vibrating arms 42 and 43 when the angular velocity ωz around the Z axis is added and when the angular velocity ωy around the Y axis is added. ωy can be detected independently.
More specifically, when the angular velocity ωz is added, the signal (voltage) V1 extracted from the first detection signal electrode 710a and the first detection ground electrode 720a is a signal (voltage) + Vz caused by the angular velocity ωz. The signal (voltage) V2 extracted from the second detection signal electrode 710b and the second detection ground electrode 720b is a signal (voltage) −Vz caused by the angular velocity ωz. That is, V1 = + Vz and V2 = −Vz.

  On the other hand, when the angular velocity ωy is added, the signal V1 extracted from the first detection signal electrode 710a and the first detection ground electrode 720a is a signal + Vy resulting from the angular velocity ωy, and the second detection signal electrode 710b and the second detection signal electrode 710b The signal V2 extracted from the detection ground electrode 720b is a signal + Vy resulting from the angular velocity ωY. That is, V1 = + Vy and V2 = + Vy. The reason why the signs are the same between the signals V1 and V2 is that, as described above, the distortion detecting means is configured to generate signals having different signs with respect to the angular velocity around the Z axis.

  Therefore, when an angular velocity ωyz about an axis having both direction components in the Y-axis direction and the Z-axis direction (that is, an axis inclined with respect to both the Y-axis and Z-axis) is applied to the gyro sensor 2, the first detection signal The signal V1 extracted from the electrode 710a and the first detection ground electrode 720a is (+ Vy) + (+ Vz), and the signal V2 extracted from the second detection signal electrode 710b and the second detection ground electrode 720b is (+ Vy). ) + (− Vz). That is, V1 = Vy + Vz and V2 = Vy−Vz.

By adding or subtracting the signals V1 and V2 obtained in this way, the angular velocity ωy around the Y axis of the angular velocity ωyz and the angular velocity ωz around the Z axis can be separated, and the angular velocity ωy and the angular velocity ωz can be separated. Each can be detected independently. Specifically, V1 + V2 = 2Vy, and the signal Vz caused by the angular velocity ωz can be eliminated. Thereby, the angular velocity ωy about the Y axis is obtained. On the other hand, V1−V2 = 2Vz, and the signal Vy resulting from the angular velocity ωy can be eliminated. As a result, the angular velocity ωz about the Z axis is obtained. According to the gyro sensor 2, the angular velocity ωy around the Y axis and the angular velocity ωz around the Z axis can be easily detected independently. Such a calculation can be performed by an IC chip (not shown) connected to the gyro sensor 2.
Note that the signs of the signals “Vz” and “Vy” described above are reversed depending on the configuration of the wiring. That is, “+ Vz” is “−Vz”, “−Vz” is “+ Vz”, “+ Vy” is “−Vy”, and “−Vy” is “+ Vy”.

Second Embodiment
Next, a second embodiment of the gyro sensor of the present invention will be described.
FIG. 9 is a plan view of a gyro sensor according to a second embodiment of the present invention, and FIG. 10 is a cross section taken along line DD and line EE in FIG.
Hereinafter, the gyro sensor of the second embodiment will be described focusing on the differences from the above-described embodiment, and the description of the same matters will be omitted.
The gyro sensor according to the second embodiment of the present invention is the same as that of the first embodiment described above, except that the output signals from the first and second detection vibrating arms are different. In addition, the same code | symbol is attached | subjected to the structure similar to 1st Embodiment mentioned above.

  As shown in FIGS. 9 and 10, in the gyro sensor 2 of the present embodiment, the piezoelectric elements 11 and 12 are formed on the upper surface (main surface) of the first detection vibrating arm 42 side by side in the X-axis direction. The piezoelectric element 11 is configured by laminating a first electrode 111, a piezoelectric film 112, and a second electrode 113 in this order. The piezoelectric element 12 is configured by laminating a first electrode 121, a piezoelectric film 122, and a second electrode 123 in this order. The piezoelectric films 112 and 122 are integrally formed. Note that the piezoelectric films 112 and 122 may not be formed integrally.

  Similarly, piezoelectric elements 13 and 14 are formed side by side in the X-axis direction on the upper surface (main surface) of the second detection vibrating arm 43. The piezoelectric element 13 is configured by laminating a first electrode 131, a piezoelectric film 132, and a second electrode 133 in this order. The piezoelectric element 14 is configured by laminating a first electrode 141, a piezoelectric film 142, and a second electrode 143 in this order. The piezoelectric films 132 and 142 are integrally formed. Note that the piezoelectric layers 132 and 142 need not be formed integrally.

  In such a configuration, when the first detection vibrating arm 42 vibrates in the detection mode excited by applying at least one of the angular velocity ωy and the angular velocity ωz, the piezoelectric elements 11 and 12 expand or contract, thereby causing the first The distortion of the detection vibrating arm 42 can be extracted as a signal (output signal) between the first electrode 111 and the second electrode 113 and between the first electrode 121 and the second electrode 123. Similarly, the distortion of the second detection vibrating arm 43 can be taken out as a signal (output signal) between the first electrode 131 and the second electrode 133 and between the first electrode 141 and the second electrode 143. .

By processing the signals extracted from the piezoelectric elements 11 to 14 in the same manner as in the first embodiment, the angular velocity ωy and the angular velocity ωz can be detected independently.
By using the piezoelectric elements 11 to 14, the distortion of the first and second detection vibrating arms 42 and 43 can be more reliably extracted as a signal with a simple configuration.
Also according to the second embodiment, the same effects as those of the first embodiment described above can be exhibited.

<Third Embodiment>
Next, a third embodiment of the gyro sensor of the present invention will be described.
FIG. 11 is a plan view of a gyro sensor according to a third embodiment of the present invention, and FIG. 12 is a cross section taken along line FF and line GG in FIG.
Hereinafter, the gyro sensor of the third embodiment will be described focusing on the differences from the above-described embodiment, and description of similar matters will be omitted.
The gyro sensor according to the third embodiment of the present invention is the same as that of the first embodiment described above except that the first and second connecting arms are provided with detection means. In addition, the same code | symbol is attached | subjected to the structure similar to 1st Embodiment mentioned above.

The gyro sensor 2 of the present embodiment has detection means for detecting each speed ωx around the X axis.
As shown in FIGS. 11 and 12, piezoelectric elements 15 and 16 are formed on the upper surface of the first connecting arm 44 side by side in the Y-axis direction. The piezoelectric element 15 is configured by laminating a first electrode 151, a piezoelectric film 152, and a second electrode 153 in this order. The piezoelectric element 16 is configured by laminating a first electrode 161, a piezoelectric film 162, and a second electrode 163 in this order. The piezoelectric films 152 and 162 are integrally formed. Note that the piezoelectric films 152 and 162 need not be formed integrally.

  Similarly, piezoelectric elements 17 and 18 are formed on the upper surface of the second connecting arm 45 side by side in the Y-axis direction. The piezoelectric element 17 is configured by laminating a first electrode 171, a piezoelectric film 172, and a second electrode 173 in this order. The piezoelectric element 18 is configured by laminating a first electrode 181, a piezoelectric film 182, and a second electrode 183 in this order. The piezoelectric films 172 and 182 are integrally formed. Note that the piezoelectric layers 172 and 182 need not be formed integrally.

In such a configuration, when the angular velocity ωx around the X axis is applied in a state where the first to fourth drive vibrating arms 46 to 49 are vibrated as in the first embodiment described above, the Coriolis force acts, By driving the Coriolis force, vibrations in the Y-axis direction (in-plane direction) indicated by arrows in FIG. 11 are newly excited in the first and second connecting arms 44 and 45. The distortion of the first connecting arm 44 due to this vibration is taken out as a signal (output signal) between the first electrode 151 and the second electrode 153 and between the first electrode 161 and the second electrode 163, and the second The angular velocity ωx is detected by taking out the distortion of the connecting arm 45 as a signal (output signal) between the first electrode 171 and the second electrode 173 and between the first electrode 181 and the second electrode 183. Can do.
According to such a gyro sensor 2, the angular velocities around the X, Y, and Z axes can be detected independently.
Also according to the third embodiment, the same effects as those of the first embodiment described above can be exhibited.

By processing the signals extracted from the piezoelectric elements 11 to 14 in the same manner as in the first embodiment, the angular velocity ωy and the angular velocity ωz can be detected independently.
By using the piezoelectric elements 11 to 14, the distortion of the first and second detection vibrating arms 42 and 43 can be more reliably extracted as a signal with a simple configuration.
Also according to the third embodiment, the same effects as those of the first embodiment described above can be exhibited.

Next, an electronic device including the gyro sensor of the present invention will be described in detail based on FIGS.
FIG. 13 is a perspective view illustrating a configuration of a mobile (or notebook) personal computer to which an electronic device including the gyro sensor of the present invention is applied. In this figure, a personal computer 1100 includes a main body portion 1104 provided with a keyboard 1102 and a display unit 1106 provided with a display portion 100. The display unit 1106 is rotated with respect to the main body portion 1104 via a hinge structure portion. It is supported movably. Such a personal computer 1100 has a built-in gyro sensor 2.

  FIG. 14 is a perspective view illustrating a configuration of a mobile phone (including PHS) to which an electronic device including the gyro sensor of the present invention is applied. In this figure, a cellular phone 1200 includes a plurality of operation buttons 1202, an earpiece 1204, and a mouthpiece 1206, and the display unit 100 is disposed between the operation buttons 1202 and the earpiece 1204. Such a cellular phone 1200 has a built-in gyro sensor 2.

FIG. 15 is a perspective view illustrating a configuration of a digital still camera to which an electronic device including the gyro sensor of the present invention is applied. In this figure, connection with an external device is also simply shown.
Here, an ordinary camera sensitizes a silver halide photographic film with a light image of a subject, whereas a digital still camera 1300 photoelectrically converts a light image of a subject with an imaging device such as a CCD (Charge Coupled Device). An imaging signal (image signal) is generated.

  A display unit is provided on the back of a case (body) 1302 in the digital still camera 1300, and is configured to display based on an imaging signal from the CCD. The display unit is a finder that displays an object as an electronic image. Function. A light receiving unit 1304 including an optical lens (imaging optical system), a CCD, and the like is provided on the front side (the back side in the drawing) of the case 1302. When the photographer confirms the subject image displayed on the display unit and presses the shutter button 1306, the CCD image pickup signal at that time is transferred and stored in the memory 1308.

In the digital still camera 1300, a video signal output terminal 1312 and an input / output terminal 1314 for data communication are provided on the side surface of the case 1302. As shown in the figure, a television monitor 1430 is connected to the video signal output terminal 1312 and a personal computer 1440 is connected to the input / output terminal 1314 for data communication as necessary. Further, the imaging signal stored in the memory 1308 is output to the television monitor 1430 or the personal computer 1440 by a predetermined operation.
Such a digital still camera 1300 incorporates a gyro sensor 2.

  In addition to the personal computer (mobile personal computer) shown in FIG. 13, the mobile phone shown in FIG. 14, and the digital still camera shown in FIG. Inkjet printers), laptop personal computers, televisions, video cameras, video tape recorders, car navigation devices, pagers, electronic notebooks (including those with communication functions), electronic dictionaries, calculators, electronic game devices, word processors, workstations, televisions Telephone, crime prevention TV monitor, electronic binoculars, POS terminal, medical equipment (for example, electronic thermometer, blood pressure monitor, blood glucose meter, electrocardiogram measuring device, ultrasonic diagnostic device, electronic endoscope), fish detector, various measuring devices, instruments Type (for example, vehicle Aircraft, gauges of a ship), can be applied to a flight simulator or the like.

As described above, the gyro sensor and the electronic device according to the present invention have been described based on the illustrated embodiment. However, the present invention is not limited to this, and the configuration of each unit is an arbitrary configuration having the same function. Can be substituted.
Moreover, the cross-sectional area is larger than the base end portion at the distal end portion of each vibrating arm (the first and second detection vibrating arms and the first, second, third, and fourth driving vibrating arms) as necessary. You may provide a mass part (hammer head). Thereby, a vibration element can be made smaller and the frequency of flexural vibration of the vibrating arm can be further reduced.

In the above-described embodiment, the vibration piece is made of a material having piezoelectricity. However, the present invention is not limited to this, and the vibration piece may be made of a silicon substrate, for example. In this case, each drive vibrating arm can be vibrated using, for example, a piezoelectric film.
In the above-described embodiment, the first to fourth drive vibrating arms have been described. However, the number of the drive vibrating arms is not particularly limited. For example, the third drive vibrating arm and the fourth drive vibrating arm are provided. The second drive vibration arm and the fourth drive vibration arm may be omitted (in this case, the remaining third drive vibration arm functions as a “second drive vibration arm”).

In the above-described embodiment, the case where the X axis, the Y axis, and the Z axis are orthogonal to each other has been described. However, the X axis, the Y axis, and the Z axis need only intersect with each other, and are not necessarily orthogonal. Also good.
The first, second, third, and fourth drive vibrating arms 46, 47, 48, and 49 have cross-sectional shapes that are asymmetric with respect to the center lines L ′ and L ″. However, the shape is not limited to the above-described one, and may be, for example, the following shape: In the following, the first drive vibrating arm 46 will be described as a representative.

A first stepped portion 465 provided between the upper surface 461 and the side surface 463 and a lower surface 462 and the side surface 464 are provided at the base end portion 46b of the first drive vibrating arm 46 shown in FIG. The formed second stepped portion 466 is formed.
A step portion 469 located between the upper surface 461 and the side surface 464 is formed at the base end portion 46b of the first drive vibrating arm 46 shown in FIG.

  11, 12, 13, 14, 15, 16, 17, 18 ... Piezoelectric element 111, 121, 131, 141, 151, 161, 171, 181 ... First electrode 112, 122, 132, 142, 152, 162 , 172, 182 ... Piezoelectric films 113, 123, 133, 143, 153, 163, 173, 183 ... Second electrode 2 ... Gyro sensor 3 ... Vibrating piece 41 ... Base 42 ... First detection vibrating arm 43 …… Second detection vibrating arm 44 …… First connecting arm 45 …… Second connecting arm 46 …… First driving vibrating arm 461 …… Upper surface 462 …… Lower surface 463,464… Side surface 465 …… First step Portion 465a …… First step surface 465b …… Second step surface 466 …… Second step portion 466a …… Third step surface 466b …… Four step surface 46a… Front end portion 46b… Base end portion 46 7 …… First groove 468 …… Second groove 469 …… Step portion 47 …… Second drive vibrating arm 471 …… Top surface 472 …… Bottom surface 473,474 …… Side surface 475a …… First step surface 475b …… First 2 step surface 476a …… third step surface 476b …… fourth step surface 47b …… base end portion 48 …… third drive vibrating arm 481 …… upper surface 482 …… lower surface 483, 484 …… side surface 485a …… first Step surface 485b …… Second step surface 486a …… Third step surface 486b …… Four step surface 48b …… Base end 49… Fourth drive vibration arm 491 …… Top surface 492 …… Bottom surface 493,494… Side surface 495a …… first step surface 495b …… second step surface 496a …… third step surface 496b …… fourth step surface 49b …… base end portion 710a …… first detection signal electrode 710b …… second detection signal electrode 720a: First detection ground electrode 720b: Second detection ground electrode 730: Drive signal electrode 740: Drive ground electrode 100 ... Display unit 1100 ... Personal computer 1102 ... Keyboard 1104 ... Main unit 1106 ... Display unit 1200 ... mobile phone 1202 ... operation buttons 1204 ... earpiece 1206 ... mouthpiece 1300 ... digital still camera 1302 ... case 1304 ... light receiving unit 1306 ... shutter button 1308 ... memory 1312 ... Video signal output terminal 1314 ··· Input / output terminal 1430 ··· TV monitor 1440 ··· Personal computer L1 ... 1st side L2 ... 2nd side L3 ... 3rd side L4 ... 4th side L5 ... 5th side L6 …… 6th side L7 …… No. Side L8 ...... eighth side S1 ...... region L ', L "...... centerline O ...... central axis

Claims (12)

When three axes intersecting each other are defined as a first axis, a second axis, and a third axis,
The base,
A first connecting arm and a second connecting arm extending oppositely from each other along the first axis from the base;
A first drive vibrating arm extending from the first connecting arm along the second axis;
A second drive vibrating arm extending from the second connecting arm along the second axis;
A first detection vibrating arm and a second detection vibrating arm extending opposite to each other along the second axis from the base,
Wherein each of the first drive vibrating arm and the second driving vibration arms, seen including a vibration component of the first axis and the direction of the third axis,
In the state where the first drive vibrating arm and the second drive vibrating arm are vibrating, the vibrations of the first detection vibrating arm and the second detection vibrating arm excited by the application of an angular velocity around the second axis. The pattern and the vibration pattern of the first detection vibration arm and the second detection vibration arm excited by applying an angular velocity around the third axis are different from each other,
When an angular velocity about the second axis is applied, the first detection vibrating arm and the second detection vibrating arm vibrate in the same direction with respect to the first axis;
When an angular velocity around the third axis is applied, the first detection vibrating arm and the second detection vibrating arm vibrate in opposite directions with respect to the first axis;
One of the angular velocity around the second axis and the angular velocity around the third axis is detected by adding the output signal from the first detection vibrating arm and the output signal from the second detection vibrating arm, and the first The other of the angular velocity around the second axis and the angular velocity around the third axis is detected by subtracting the output signal from the first detection vibrating arm and the output signal from the second detection vibrating arm. Gyro sensor.   2. The gyro sensor according to claim 1, wherein the first drive vibrating arm and the second drive vibrating arm have the same vibration component of the third axis during driving vibration.   3. The gyro sensor according to claim 1, wherein the first drive vibration arm and the second drive vibration arm have vibration components of the first axis during drive vibration in opposite directions.   Each of the first drive vibrating arm and the second drive vibrating arm has a portion in which a cross-sectional shape in the second axial direction is asymmetric with respect to the center line in the first axial direction and the center line in the third axial direction. The gyro sensor according to any one of claims 1 to 3, further comprising: Each of the first drive vibrating arm and the second drive vibrating arm is:
A first surface and a second surface that are in reverse relation to each other;
A first groove provided in the first surface;
A second groove provided on the second surface,
The gyro sensor according to claim 4, wherein the first groove and the second groove are arranged in the direction of the first axis in a plan view from the normal direction of the first surface. Each of the first drive vibrating arm and the second drive vibrating arm is:
A first surface and a second surface that are in reverse relation to each other;
A first side surface and a second side surface connecting the first surface and the second surface;
The gyro sensor according to claim 4, wherein at least one of the first side surface and the second side surface includes a stepped portion. A third drive vibration arm extending in a direction opposite to a direction in which the first drive vibration arm extends;
The gyro sensor according to claim 1, further comprising a fourth drive vibrating arm extending in a direction opposite to a direction in which the second drive vibrating arm extends. The first detection vibrating arm and the second detection vibrating arm are made of a piezoelectric material,
The gyro sensor according to any one of claims 1 to 7 , wherein cross-sectional shapes of the first detection vibrating arm and the second detection vibrating arm are substantially rectangular, and electrodes are provided on each surface. The first detection vibrating arm and the second detection vibrating arm are:
Composed of piezoelectric material,
The first detection vibrating arm and the second detection vibrating arm include a pair of main surfaces that are in a front-back relationship with each other and a pair of side surfaces that connect the main surfaces, and at least one of the pair of main surfaces has a groove. is provided, the gyro sensor according to any one of from above to the side electrode opposite to the grooves of the inner wall and the inner wall claims 1 provided 7. It said first detection vibration arm and the second detection vibration arms, any one of from piezoelectric elements arranged piezoelectric film between the first electrode and the second electrode claims 1 provided on the main surface 9 The gyro sensor described in 1. The gyro sensor according to any one of claims 1 to 10 , wherein at least one of the first connecting arm and the second connecting arm is provided with a strain detecting means. An electronic apparatus comprising the gyro sensor according to any one of claims 1 to 10 .

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