JP5824492B2 - Vibration gyro element and gyro sensor - Google Patents

Description

  The present invention relates to a vibration gyro element used for detecting angular velocity, a support structure for the vibration gyro element, and a gyro sensor.

In recent years, a gyro sensor in which a vibrating gyro element is housed in a container is often used for camera shake correction of an imaging device and attitude control of a mobile navigation system such as a vehicle using a GPS satellite signal.
As a vibration gyro element, for example, a so-called double T-type vibration gyro element in which a substantially T-shaped drive vibration system is arranged symmetrically with respect to a central detection vibration system is known (see Patent Document 1 and FIG. 1).
In these gyro sensors, there is a demand for miniaturization in order to improve portability and increase the degree of freedom in device design. In order to reduce the size of the gyro sensor, it is necessary to reduce the size of the gyro element. Normally, the gyro element is supported by bonding the central base (center of gravity) of the gyro element to the substrate, etc. However, as the gyro element is made smaller, the support area with the substrate becomes smaller and vibration or impact occurs. There is a problem that the strength cannot be ensured when. For this reason, for example, as shown in Patent Document 1 (FIG. 4), a structure has been proposed in which a support frame is extended from the base and each of the base and the support frame is supported.

Japanese Patent Laid-Open No. 2001-12955 (FIGS. 1 and 4)

  However, in this conventional gyro element, the detection vibration is suppressed by supporting the base to reduce the detection sensitivity of the angular velocity, and the support frame is provided outside the drive vibration system and the detection vibration system of the gyro element. Therefore, there is a limit to downsizing the gyro element.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a vibrating gyro element and a vibrating gyroscope that maintain the angular velocity detection sensitivity of the vibrating gyro element and ensure the support strength to enable downsizing. An object is to provide a support structure for an element and a gyro sensor.

In order to solve the above-mentioned problems, a vibrating gyro element according to the present invention includes a base, a pair of detection vibrating arms linearly extending from the base to both sides, and the detection vibrating arms from the base to both sides. A pair of connecting arms extending in a direction orthogonal to each other, a pair of drive vibrating arms extending from the front end of each connecting arm to both sides orthogonal thereto, and each detection from the base Two pairs of beams extending along the arm and a pair of support portions connected to the beams extending in the same direction are provided on the same plane, and the support portions are provided for the detection vibrations. The arm is arranged in the direction in which the arm extends and is arranged outside the detection vibrating arm and between the driving vibrating arms. According to another aspect of the present invention, there is provided a vibrating gyro element including a base, and a vibrating body that includes a first direction passing through the center of gravity of the base and a vibrating unit that vibrates along a direction opposite to the first direction, and the base In contrast, the first support portion disposed on one side of the second direction perpendicular to the first direction and passing through the center of gravity of the base portion is connected to the base portion and the first support portion. First and second beams, wherein the first and second beams extend along the first direction or a direction opposite to the first direction. At least two portions disposed between the base portion and the first support portion, and the first component portion extending along the second direction. The beam and the second beam are symmetric with respect to a line defining the second direction. In addition, a vibrating body including a base, a detection vibration part that extends from the base and detects and vibrates, and a drive vibration part that drives and vibrates, and the base is disposed on the first direction side passing through the center of gravity of the base. The first support portion, the second support portion disposed on the opposite side of the first direction with respect to the base portion, and the base portion and the first support portion are connected to each other. First and second beams, and third and fourth beams connecting the base portion and the second support portion, wherein the first and second beams are A first component extending from the first support and extending along a direction opposite to the first direction; and a direction perpendicular to the direction of the first direction from the first component. Extending along the same direction as the second component extending from the second component and the extending direction of the first component from the second component. And a fourth component extending from the third component along a direction opposite to the extending direction of the second component. The third and fourth beams extend from the second support portion and extend along the first direction, and from the fifth component to the first direction. A sixth component extending along a direction orthogonal to the direction of the fifth component, and a seventh component extending from the sixth component along the same direction as the extension direction of the fifth component. And an eighth component extending from the seventh component along a direction opposite to the extending direction of the sixth component, the first beam and The second beam, the third beam, and the fourth beam are symmetric with respect to a line that defines the first direction. To.

  According to this configuration, by forming the beam extending from the base portion of the vibrating gyro element and the support portion connecting the beam, a large area of the support portion can be secured. The support strength can be improved while maintaining the angular velocity detection sensitivity by adhering and supporting the support portion. In addition, the vibration gyro element can be reduced in size by disposing the support portion in the direction in which the detection vibration arm extends, outside the detection vibration arm and between the drive vibration arms.

  In the vibrating gyro element of the present invention, the length of the detection vibrating arm is shorter than the length of the driving vibrating arm.

  In this way, the area of the support portion can be increased, and the support strength of the vibrating gyro element can be improved.

  The vibrating gyro element according to the present invention is characterized in that the pair of support portions are provided at rotationally symmetric positions with respect to the center of gravity of the vibrating gyro element.

  According to this configuration, the balance of the vibration gyro element can be secured and a stable posture can be maintained.

  Further, the vibration gyro element support structure of the present invention includes the vibration gyro element, a support base on which the vibration gyro element is placed, and the support portion and the support base of the vibration gyro element. And a fixing member.

  According to this configuration, since the support portion can be formed to have a large area, the support portion is supported by the fixing member without supporting the base portion of the vibration gyro element, and the support is ensured while maintaining the angular velocity detection sensitivity. Is possible.

  In the vibrating gyro element support structure of the present invention, the fixing member is made of an elastic material.

  According to this configuration, since the fixing member has elasticity, it is possible to soften external vibrations or impacts and to keep the driving vibration and the detection vibration of the vibrating gyro element stable. And the fixed member functions as a buffer material for the minute vibration leaking to the support part, and the influence on the drive vibration and the detection vibration can be reduced.

  Further, the gyro sensor of the present invention, the vibration gyro element, a support base on which the vibration gyro element is placed, a fixing member for fixing the support portion and the support base of the vibration gyro element, A drive circuit for driving and vibrating the vibrating gyro element, and a detection circuit for detecting a detection vibration generated in the vibrating gyro element when an angular velocity is applied to the vibrating gyro element.

  According to this configuration, the support strength of the vibration gyro element is improved by adhering and supporting the support portion of the vibration gyro element while maintaining the angular velocity detection sensitivity, and the size of the vibration gyro element is reduced and the size of the gyro sensor is reduced. Can be provided.

1 is a schematic plan view showing a vibrating gyro element of the present embodiment. The schematic sectional drawing which shows a gyro sensor. The schematic plan view explaining the drive vibration state of a vibration gyro element. The schematic plan view explaining the detection vibration state of a vibration gyro element. The schematic plan view which shows the modification of a vibration gyro element. The schematic plan view which shows the modification of a vibration gyro element. The schematic plan view which shows the modification of a vibration gyro element. The schematic plan view which shows the modification of a vibration gyro element. The schematic plan view which shows the modification of a vibration gyro element.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings.
(Embodiment)
FIG. 1 is a schematic plan view showing a vibrating gyro element of this embodiment.
The vibrating gyro element 1 is made of quartz that is a piezoelectric material. Quartz has an X axis called an electric axis, a Y axis called a mechanical axis, and a Z axis called an optical axis. The vibrating gyro element 1 has a predetermined thickness in the Z-axis direction and is formed in the XY plane.

The vibrating gyro element 1 includes a pair of detection vibrating arms 11a and 11b extending linearly from the base 10 to both the upper and lower sides in the figure, and a direction perpendicular to the detection vibrating arms 11a and 11b from the base 10 in the figure. A pair of connecting arms 13a, 13b extending to the left and right sides, and a pair of left and right drives extending from the tip of each connecting arm 13a, 13b to the upper and lower sides in the figure in parallel with the detection vibrating arms 11a, 11b Vibration arms 14a, 14b, 15a, and 15b.
Further, detection electrodes (not shown) are formed on the surfaces of the detection vibrating arms 11a and 11b, and drive electrodes (not shown) are formed on the surfaces of the driving vibration arms 14a, 14b, 15a and 15b. In this way, a detection vibration system that detects the angular velocity is configured by the detection vibration arms 11a and 11b, and the drive that drives the vibration gyro element by the connection arms 13a and 13b and the drive vibration arms 14a, 14b, 15a, and 15b. It constitutes a vibration system.

In addition, weights 12a and 12b are formed at the respective distal ends of the detection vibrating arms 11a and 11b, and weights 16a, 16b and 17a are formed at the respective distal ends of the driving vibrating arms 14a, 14b, 15a and 15b. 17b are formed to improve the detection sensitivity of the angular velocity. Here, the detection vibrating arms 11a and 11b include weight portions 12a and 12b, respectively, and the driving vibrating arms 14a, 14b, 15a and 15b have names including the weight portions 16a, 16b, 17a and 17b, respectively.
The detection vibrating arms 11a and 11b are formed to be shorter than the driving vibrating arms 14a, 14b, 15a and 15b.

Furthermore, a pair of L-shaped beams 20a and 20b extending from the base 10 to the left and right sides in the figure in a direction orthogonal to the detection vibrating arm 11a and extending in parallel with the detection vibrating arm 11a on the way. Both ends of the beams 20a and 20b are connected to the support portion 22a. Similarly, a pair of L-shaped beams 21a, 21b extending from the base 10 to the left and right sides in the drawing in a direction orthogonal to the detection vibrating arm 11b and extending in parallel with the detection vibrating arm 11b in the middle. The ends of the beams 21a and 21b are both connected to the support portion 22b.
The pair of support portions 22a and 22b is a direction in which each of the detection vibrating arms 11a and 11b extends and between the detection vibrating arms 11a and 11b and between the driving vibrating arms 14a, 14b, 15a, and 15b. Are arranged. Further, the pair of support portions 22 a and 22 b are disposed at rotationally symmetric positions with respect to the center of gravity G of the vibrating gyro element 1.

Next, the operation of the vibrating gyro element 1 will be described.
3 and 4 are schematic plan views for explaining the operation of the vibrating gyro element. In FIGS. 3 and 4, each vibrating arm is represented by a line in order to simply express the vibration form, and the beams 20a, 20b, 21a, 21b and the support portions 22a, 22b described above are omitted.

  In FIG. 3, the drive vibration state of the vibration gyro element 1 will be described. In the state where the angular velocity is not applied, the vibration gyro element 1 causes the vibration arms for driving 14a, 14b, 15a, and 15b to bend and vibrate in the direction indicated by the arrow E. In this bending vibration, a vibration state indicated by a solid line and a vibration state indicated by a two-dot chain line are repeated at a predetermined frequency. At this time, since the drive vibrating arms 14a and 14b and the drive vibrating arms 15a and 15b perform a line-symmetric vibration with respect to the Y axis passing through the center of gravity G, the base 10, the connecting arms 13a and 13b, and the detection vibration The arms 11a and 11b hardly vibrate.

  When an angular velocity ω about the Z axis is applied to the vibration gyro element 1 in a state where this drive vibration is being performed, vibration as shown in FIG. 4 is performed. That is, the Coriolis force in the direction of arrow B acts on the driving vibrating arms 14a, 14b, 15a, 15b and the connecting arms 13a, 13b constituting the driving vibration system, thereby exciting new vibrations. This vibration in the direction of arrow B is a circumferential vibration with respect to the center of gravity G. At the same time, the detection vibration arms 11a and 11b are excited in response to the vibration indicated by the arrow B in the direction indicated by the arrow C. Then, a detection electrode formed on the vibrating arms for detection 11a and 11b detects the distortion of the piezoelectric material generated by this vibration, and the angular velocity is obtained.

  At this time, the peripheral edge of the base 10 vibrates in the arrow D direction and in the circumferential direction with respect to the center of gravity G. This is because the detected vibration is not only balanced vibration between the drive vibration system and the detection vibrating arms 11a and 11b but also balanced vibration including the base portion 10. The vibration amplitude of the peripheral portion of the base 10 indicated by the arrow D is very small compared to the vibration amplitude of the drive vibration system indicated by the arrow B or the vibration amplitude of the detection vibrating arms 11a and 11b indicated by the arrow C. When the base 10 is bonded and fixed, vibrations at the peripheral edge of the base 10 are suppressed by this fixing, and detection vibrations are also suppressed. Therefore, the angular velocity detection sensitivity is lowered by supporting the base 10.

Next, the supporting structure of the vibrating gyro element and the gyro sensor will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view showing the gyro sensor, and the vibrating gyro element 1 is shown as a cross section taken along the line AA in FIG.
The gyro sensor 80 includes the vibration gyro element 1, an IC 84, a container 81, and a lid 86. An IC 84 is disposed on the bottom surface of the container 81 made of ceramic or the like, and is electrically connected to a wiring (not shown) formed in the container 81 with a wire 85 such as Au. The IC 84 includes a drive circuit for driving and vibrating the vibration gyro element 1 and a detection circuit for detecting a detection vibration generated in the vibration gyro element 1 when an angular velocity is applied. In the vibrating gyro element 1, a support 82 formed in the container 81 and the support portions 22 a and 22 b of the vibrating gyro element 1 are bonded and supported via a fixing member 83 such as a conductive adhesive. In addition, wiring (not shown) is formed on the surface of the support base 82, and conduction between the electrode of the vibrating gyro element 1 and the wiring is made through a fixing member 83. The fixing member 83 is preferably made of an elastic material. As the fixing member 83 having elasticity, a conductive adhesive based on silicone is known. The inside of the container 81 is held in a vacuum atmosphere at the upper part of the container 81 and sealed with a lid 86.

As described above, the vibration gyro element 1 and the support structure of the vibration gyro element 1 according to the present embodiment form the support portions 22a and 22b that connect the beams 20a, 20b, 21a, and 21b extended from the base portion 10. As a result, the areas of the support portions 22a and 22b can be secured large, and the support strength can be improved.
Further, the beams 20a, 20b, 21a, and 21b extending from the base portion 10 are elastic because they are made of quartz, and vibrations at the peripheral portion of the base portion 10 are not suppressed, and the angular velocity detection sensitivity is reduced. There is nothing to do.

Further, the support portions 22a and 22b are arranged in the extending direction of the detection vibrating arms 11a and 11b, outside the detection vibrating arms 11a and 11b and between the driving vibrating arms 14a, 14b, 15a, and 15b. Thus, the vibration gyro element 1 can be miniaturized.
Further, since the pair of support portions 22a and 22b are provided at rotationally symmetric positions with respect to the center of gravity G of the vibration gyro element 1, the balance of the vibration gyro element 1 can be secured and a stable posture can be maintained. And good characteristics can be obtained.

Further, in the support structure of the vibration gyro element 1, since the fixing member 83 is made of an elastic material, vibrations and impacts from the outside can be softened, and driving vibration and detection vibration can be kept stable. And the fixing member 83 functions as a buffer material for the minute vibration leaking to the support portions 22a and 22b, and the influence on the drive vibration and the detection vibration can be reduced.
Furthermore, the gyro sensor 80 equipped with the vibrating gyro element 1 supported by the support structure can be miniaturized while maintaining the detection sensitivity of the angular velocity.
(Modification of vibrating gyro element)

5 to 9 are schematic plan views showing modifications of the vibrating gyro element. These modifications are characterized by the shape of the beam and the support portion shown in FIG. 1, and the same components as those in FIG.
In FIG. 5, a pair of beams 30a and 30b extending in parallel with the vibrating arm 11a for detection are formed from both sides of the base 10 of the vibrating gyro element 2, and the ends of the beams 30a and 30b are connected to the support portion 32a. ing. Similarly, a pair of beams 31a and 31b extending in parallel with the detection vibrating arm 11b from both sides of the base portion 10 are formed, and the tips of the beams 31a and 31b are connected to the support portion 32b.
The pair of support portions 31a and 31b is in the direction in which the detection vibrating arms 11a and 11b extend and between the detection vibrating arms 11a and 11b and between the driving vibrating arms 14a, 14b, 15a, and 15b. Is arranged.
The vibrating gyro element 2 has a support structure similar to that of the above-described embodiment, and the support portions 32a and 32b are bonded and supported on a support base by a fixing member such as a conductive adhesive.

Next, in FIG. 6, the vibrating gyro element 3 has a substantially S-shaped beam 40 a, which extends from the four corners of the base 10 in the direction in which each of the detection vibrating arms 11 a and 11 b extends. 40b, 41a, 41b are provided. The ends of the beams 40a and 40b are connected to the support portion 42a, and the beams 41a and 41b are connected to the support portion 42b.
The pair of support portions 41a and 41b are in the direction in which the detection vibrating arms 11a and 11b extend and between the detection vibrating arms 11a and 11b and between the driving vibrating arms 14a, 14b, 15a, and 15b. Are arranged.
The vibration gyro element 3 has a support structure similar to that of the above-described embodiment, and the support portions 42a and 42b are bonded and supported on a support base by a fixing member such as a conductive adhesive.

In FIG. 7, the vibrating gyro element 4 includes substantially S-shaped beams 50 a, 50 b, 51 a, which extend from the four corners of the base 10 in the direction perpendicular to the detection vibrating arms 11 a, 11 b. 51b is provided. The ends of the beams 50a and 50b are connected to the support portion 52a, and the beams 51a and 51b are connected to the support portion 52b.
The pair of support portions 51a and 51b are in the direction in which the detection vibrating arms 11a and 11b extend and between the detection vibrating arms 11a and 11b and between the driving vibrating arms 14a, 14b, 15a, and 15b. Are arranged.
The vibrating gyro element 4 has a support structure similar to that of the above-described embodiment, and the support portions 52a and 52b are bonded and supported on a support base by a fixing member such as a conductive adhesive.

Next, in FIG. 8, the vibrating gyro element 5 is provided with beams 60 a, 60 b, 61 a, and 61 b extending obliquely from four corners of the base 10. The tips of the beams 60a and 60b are connected to the support portion 62a, and the beams 61a and 61b are connected to the support portion 62b.
The pair of support portions 61a and 61b is a direction in which each of the detection vibrating arms 11a and 11b extends, between the detection vibrating arms 11a and 11b and between the driving vibrating arms 14a, 14b, 15a, and 15b. Is arranged.
The vibration gyro element 5 has a support structure similar to that of the above-described embodiment, and the support portions 62a and 62b are bonded and supported on a support base by a fixing member such as a conductive adhesive.

FIG. 9 shows a configuration in which the weight portions 16a, 16b, 17a, and 17b are not provided in the vibrating gyro element 1 described with reference to FIG.
The vibrating gyro element 6 extends from the four corners of the base 10 to the left and right sides in the figure in a direction orthogonal to the detection vibrating arms 11a and 11b, and extends in parallel with the detection vibrating arms 11a and 11b. L-shaped beams 70a, 70b, 71a, 71b are provided. The ends of the beams 70a and 70b are connected to the support portion 72a, and the beams 71a and 71b are connected to the support portion 72b.
The pair of support portions 71a and 71b are in the extending direction of the detection vibrating arms 11a and 11b and between the detection vibrating arms 11a and 11b and between the driving vibrating arms 14a, 14b, 15a and 15b. Is arranged.
The vibration gyro element 6 has a support structure similar to that of the above-described embodiment, and the support portions 72a and 72b are bonded and supported on a support base by a fixing member such as a conductive adhesive.

As described above, the crystal that is the material of the vibrating gyro element has inherent elasticity, but the elasticity of the beam can be adjusted by appropriately changing the length and shape of the beam extending from the base portion 10. . From this, it is possible to suppress the vibration of the base 10 from being transmitted to the support portion, and to obtain stable drive vibration and detection vibration.
The above-described modification of the vibration gyro element also has the same operation as described in the present embodiment, and can enjoy the same effect.

Note that the vibrating gyro element of this embodiment can be integrally formed by etching using a photolithography technique, and a large number of vibrating gyro elements can be formed from one crystal wafer.
Further, as the material of the vibrating gyro element, other piezoelectric materials such as lithium tantalate (LiTaO ₃ ) or lithium niobate (LiNbO ₅ ) may be used. Furthermore, it is possible to carry out using not only a piezoelectric material but also a constant elastic material represented by an erimba material.

  1, 2, 3, 4, 5, 6 ... vibrating gyro element, 10 ... base, 11a, 11b ... detecting vibrating arm, 13a, 13b ... connecting arm, 14a, 14b ... driving vibrating arm, 15a, 15b ... driving vibration Arm, 20a, 20b, 21a, 21b ... beam, 22a, 22b ... support part, 80 ... gyro sensor, 82 ... support base, 83 ... fixing member, 84 ... IC including drive circuit and detection circuit, G ... center of gravity.

Claims (5)

Group unit, the first detection vibration arms that extend along a first direction from said base portion, vibrating second detection which extends in a direction opposite to the first direction from the base portion An arm, a first connecting arm extending from the base in a second direction orthogonal to the first direction, a second connecting arm extending from the base in a direction opposite to the second direction, A first driving vibration arm extending from the first connecting arm in the first direction, and a second driving vibration extending from the first connecting arm in a direction opposite to the first direction. An arm, a third driving vibration arm extending from the second connecting arm in the first direction, and a fourth extending from the second connecting arm in a direction opposite to the first direction. a body vibration has a drive vibration arms,
Relative to the base, a first support part arranged with the center of gravity of said base to passing Ru said first direction,
A second support portion disposed on a side opposite to the first direction with respect to the base portion;
A first beam and a second beam connecting the base and the first support;
A third beam and a fourth beam connecting the base and the second support;
With
The first beam and the second beam has a first component which extends in a direction opposite to the extending issued the first direction from the first support portion, from said first component wherein the second component which extends second way along direction, the second from said component of the first part of the extension third that extend along the same direction and direction And a fourth component extending from the third component along a direction opposite to the extending direction of the second component,
The third beam and the fourth beam comprises a fifth component of which is extended extending in said first direction from said second support portion, said fifth component from said second way direction the sixth and component of the sixth seventh component of the components extend along the same direction and the extending direction of the fifth component of which extends along the, An eighth component extending from the seventh component along the direction opposite to the extending direction of the sixth component;
The vibrating gyro element, wherein the first beam, the second beam, the third beam, and the fourth beam are line-symmetric with respect to a line that defines the first direction. . The vibrating gyro element according to claim 1,
The vibrating gyro element, wherein the first beam, the second beam, the third beam, and the fourth beam are line-symmetric with respect to a line that defines the second direction. . The vibrating gyro element according to claim 1 or 2,
The vibrator, the first support portion, the second support portion, the first beam, the second beam, the third beam, and the fourth beam are integrally formed from a crystal plate. A vibrating gyro element characterized by being made . The vibrating gyro element according to any one of claims 1 to 3,
The length of the first detection vibrating arm is equal to or shorter than the length of the first connecting arm and the third connecting arm,
The vibration gyro element according to claim 1, wherein a length of the second detection vibrating arm is equal to or less than a length of the second connecting arm and the fourth connecting arm. A vibrating gyro element according to any one of claims 1 to 4,
Gyro sensor, wherein the benzalkonium equipped with a support base said vibrating gyro element is placed.

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