JP6083110B2 - Vibration element, vibration device, gyro sensor and electronic equipment - Google Patents

Description

  The present invention relates to a vibration element, a vibration device, and an electronic apparatus.

For example, as a vibration device such as a crystal oscillator for detecting an angular velocity, one including a tuning fork type vibration element including a plurality of vibration arms is known (for example, see Patent Document 1).
For example, the vibrating device described in Patent Literature 1 includes a vibrating element having a base and two vibrating arms that are aligned in the X-axis direction from the base and extend in the Y-axis direction. Each vibrating arm has a groove formed on each of an upper surface and a lower surface facing in the Z-axis direction, and the cross-sectional shape thereof is an “S” shape. By making each vibrating arm have such a shape, it is possible to suppress the variation of the Q value while maintaining the mechanical strength.

  Here, in the vibration element of Patent Document 1, since the cross-sectional shape of each vibration arm is asymmetric in the left-right direction (asymmetric with respect to the center line in the X-axis direction), when each vibration arm is vibrated in the Z-axis direction, Axial vibration is generated, and as a result, oblique vibration is generated in the direction in which the Z-axis direction and the X-axis direction are combined. Such oblique vibration has an effect of improving the vibration balance of the vibrating arm and improving the vibration characteristics of the vibration element.

  However, as in the vibration element of Patent Document 1, in order to obtain an “S” -shaped cross section, grooves formed on the upper surface and the lower surface must be formed deep and the width must be suppressed. It is difficult to form the groove deeply while suppressing its width. For example, the groove formed on the upper surface may penetrate the lower surface, or may open to the side surface and the side surface may be lost. . In other words, Patent Document 1 has a problem that it is difficult to process the vibrating arm.

WO2010 / 047115

  An object of the present invention is to provide a vibrating element that is relatively easy to process and that can exhibit excellent vibration characteristics, and to provide a highly reliable vibrating device and electronic apparatus including the vibrating element. It is to provide.

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 vibration element of the present invention includes a base,
And a drive arm including a first surface, a second surface in front-back relation with the first surface, and a pair of side surfaces connecting the first surface and the second surface. And
The drive arm is provided with a step portion between at least one of the first surface and the second surface and at least one of the pair of side surfaces, and a groove portion in at least one of the first surface and the second surface. Is provided,
The cross-sectional shape of the drive arm is asymmetric with respect to the center line in the width direction and the center line in the thickness direction of the drive arm.
As a result, it is possible to obtain a vibrating element having a drive arm that can be vibrated obliquely by simple processing. By having the drive arm that vibrates obliquely, vibration leakage is suppressed, and the vibration element of the present invention has excellent vibration characteristics. Further, since the processing is simple, the yield is improved. Further, the drive arm can be vibrated obliquely with low impedance.

[Application Example 2]
In the resonator element according to the aspect of the invention, it is preferable that the groove is provided on the first surface and the second surface.
Thereby, for example, by disposing driving electrodes for driving the driving arms in the respective grooves, it is excellent in electric field efficiency when the driving arms are flexibly vibrated, and the driving arms can be flexed and vibrated efficiently.

[Application Example 3]
In the resonator element according to the aspect of the invention, it is preferable that the step portion is provided on one side of the pair of side surfaces of the first surface and on the other side of the pair of side surfaces of the second surface.
Thereby, the shape of an asymmetric part can be made into a simpler shape. Further, by adopting such a shape, the drive arm can be vibrated obliquely more smoothly.

[Application Example 4]
In the resonator element according to the aspect of the invention, it is preferable that the stepped portion has a polygonal shape or a curved shape in the cross-sectional shape.
For example, in the case of a curved shape, stress concentration on the boundary portion of the step surface is suppressed, and the drive arm can be vibrated obliquely more smoothly. Further, when a driving electrode is formed on the stepped portion, it becomes easier to form the electrode along the stepped surface, and for example, it effectively prevents disconnection at the boundary portion of the stepped surface or peeling of the electrode. be able to.

[Application Example 5]
In the resonator element according to the aspect of the invention, it is preferable that electrodes are provided on the inner wall surface of the groove and the surface of the stepped portion.
Thereby, since the distance between the opposing electrodes can be shortened, the driving arm can be vibrated with low impedance.

[Application Example 6]
In the vibration element according to the aspect of the invention, it is preferable that the driving arm includes a vibration component in a normal direction of the first surface and the second surface and a vibration component in a normal direction of the pair of side surfaces.
Thereby, a drive arm can be vibrated with sufficient balance.
[Application Example 7]
The vibration device of the present invention includes the vibration element of the present invention,
And a package containing the vibration element.
Thereby, it is possible to provide a vibration device such as an oscillator having excellent reliability.

[Application Example 8]
An electronic apparatus according to the present invention includes the vibration element according to the present invention.
Accordingly, it is possible to provide electronic devices such as a mobile phone, a personal computer, and a digital camera that are excellent in reliability.

It is sectional drawing which shows the vibration device which concerns on 1st Embodiment of this invention. It is a top view which shows the vibration element with which the vibration device shown in FIG. 1 was equipped. It is the sectional view on the AA line in FIG. FIG. 4 is an enlarged cross-sectional view of the drive arm shown in FIG. 3. It is sectional drawing which shows the modification of the drive arm shown in FIG. FIG. 3 is a cross-sectional view for explaining the operation of the vibration element shown in FIG. 2. It is sectional drawing of the drive arm of the vibration element with which the vibration device which concerns on 2nd Embodiment of this invention is provided. It is a top view of a vibration element with which a vibration device concerning a 3rd embodiment of the present invention is provided. It is sectional drawing of the vibration element with which the vibration device which concerns on 4th Embodiment of this invention is provided. It is sectional drawing of the vibration element with which the vibration device which concerns on 4th Embodiment of this invention is provided. It is an electronic device (notebook type personal computer) provided with the vibration element of this invention. It is an electronic device (cellular phone) provided with the vibration element of the present invention. It is an electronic device (digital still camera) provided with the vibration element of the present invention. It is sectional drawing which shows the modification of the drive arm shown in FIG.

Hereinafter, a resonator element, a resonator device, a resonator device, and an electronic apparatus according to the invention will be described in detail based on embodiments shown in the accompanying drawings.
<First Embodiment>
1 is a cross-sectional view showing a vibrating device according to the first embodiment of the present invention, FIG. 2 is a top view showing a vibrating element provided in the vibrating device shown in FIG. 1, and FIG. 3 is A in FIG. FIG. 4 is an enlarged cross-sectional view of the drive arm shown in FIG. 3, FIG. 5 is a cross-sectional view showing a modification of the drive arm shown in FIG. 4, and FIG. 6 is a cross-sectional view of the vibration element shown in FIG. It is sectional drawing for demonstrating operation | movement.

In each figure, for convenience of explanation, the x axis, the y axis, and the z axis are shown as three axes orthogonal to each other. Hereinafter, a direction parallel to the x-axis is referred to as an “x-axis direction”, a direction parallel to the y-axis is referred to as a “y-axis direction”, and a direction parallel to the z-axis is referred to as a “z-axis direction”. In the following, a plane defined by the x-axis and the y-axis is referred to as an “xy” plane, and a plane defined by the y-axis and the z-axis is referred to as a “yz plane”. The defined plane is referred to as an “xz plane”. In the following description, for convenience of explanation, the upper side in FIG. 1 is referred to as “upper”, the lower side as “lower”, the right side as “right”, and the left side as “left”.
A vibration device 1 illustrated in FIG. 1 includes a vibration element 2 and a package 9 that houses the vibration element 2. Hereinafter, each part which comprises the vibration device 1 is demonstrated in detail sequentially.

[Vibration element]
First, the vibration element 2 will be described.
As shown in FIG. 2, the vibration element 2 is a three-leg tuning fork type vibration element. The vibration element 2 of the present embodiment is used as a vibrator for generating an electric signal that vibrates at a predetermined frequency (resonance frequency).
Such a vibrating element 2 includes a base 4 and a piezoelectric substrate 3 constituted by three vibrating arms 5, 6, 7 extending from the base 4, and a plurality of electrodes formed on the piezoelectric substrate 3. And have.

  The piezoelectric substrate 3 is made of a piezoelectric material. Examples of such a piezoelectric material include crystal, lithium tantalate, lithium niobate, lithium borate, and barium titanate. In particular, quartz is preferable as the piezoelectric material constituting the piezoelectric substrate 3. When the piezoelectric substrate 3 is made of quartz (Z cut plate or the like), the vibration characteristics (particularly frequency temperature characteristics) of the piezoelectric substrate 3 can be made excellent. Further, the piezoelectric substrate 3 can be formed with high dimensional accuracy by etching. Note that the piezoelectric substrate 3 does not necessarily have piezoelectricity. For example, the vibrating arms 5, 6, and 7 may be vibrated using a piezoelectric film using a silicon substrate.

(Base 4)
The base portion 4 has a plate shape that extends in the xy plane and has a thickness in the z-axis direction. The base 4 is formed to have a thickness equal to that of the vibrating arms 5, 6, and 7. Three bases 4 are connected to three vibrating arms 5, 6, and 7.
Among these vibrating arms 5, 6, 7, the vibrating arms 5, 6 function as a driving arm for driving the vibrating element 2, and the vibrating arm 7 cancels the vibration of the vibrating arms 5, 6 in the Z direction. It functions as an adjustment arm for. Hereinafter, for convenience of explanation, the vibrating arm 5 and the driving arm 6 are also referred to as “driving arm 5” and “driving arm 6”, respectively, and the vibrating arm 7 is also referred to as “adjustment arm 7”.

  The drive arms 5 and 6 are connected to both ends of the base 4 in the x-axis direction, and the adjustment arm 7 is connected to the center of the base 4 in the x-axis direction. These three vibrating arms 5 to 7 are provided so as to extend in the y-axis direction from the base 4 so as to be parallel to each other. Further, the three vibrating arms 5 to 7 are spaced apart and arranged at equal intervals in the x-axis direction. Each of the three vibrating arms 5 to 7 has a longitudinal shape, and its end is a fixed end and the tip is a free end.

(Drive arm 5)
As shown in FIGS. 2 and 3, the drive arm 5 extends in the Y-axis direction. Such a vibrating arm 5 is a yz plane and has an asymmetric cross-sectional shape with respect to the center line L ′ in the width direction (X-axis direction) and the center line L ″ in the thickness direction (Z-axis direction) of the drive arm 5. By making the driving arm 5 in such an asymmetric shape, the driving arm 5 has a direction having both components in the x-axis direction and the z-axis direction, in other words, the z-axis and the z-axis, as will be described later. Bending vibration (hereinafter, also referred to as “oblique vibration”) can be performed in a direction inclined with respect to both axes.

  Specifically, as shown in FIG. 4, the driving arm 5 is opposed (separated) in the z-axis direction, and has an upper surface (first surface) 511 and a lower surface (first surface) configured by xy planes in a front-back relationship. 2 surfaces) 512 and a pair of side surfaces (third surface, fourth surface) 513, 514 connecting the upper surface 511 and the lower surface 512. Further, the drive arm 5 is positioned on one side of the upper surface 511 in the x-axis direction (on the adjustment arm 7 side) and opens to the side surface 513, and the lower surface 512 in the x-axis direction. A second stepped portion (stepped portion) 54 that is located on the other side (the side opposite to the adjustment arm 7) and opens to the side surface 514 is formed. Each of the first and second stepped portions 53 and 54 extends in the y-axis direction and is formed across the connecting portion with the base portion 4.

  The first step portion 53 is formed on the adjustment arm 7 side (one side) from the bisection point P. The first stepped portion 53 is configured by a yz plane and is configured by a first stepped surface 531 connected to the upper surface 511 and a second stepped surface formed by the xy plane and connected to the first stepped surface 531 and the side surface 513. A step surface 532. On the other hand, the second step portion 54 is located on the opposite side (the other side) to the adjustment arm 7 with respect to the bisection point P. The second stepped portion 54 is configured by a yz plane and is configured by a third stepped surface 541 connected to the lower surface 512 and a fourth stepped surface formed by the xy plane and connected to the third stepped surface 541 and the side surface 514. A step surface 542. That is, the first and second step portions 53 and 54 have a polygonal cross-sectional shape.

Here, in other words, the shape of the drive arm 5 can be expressed as follows. That is, as shown in FIG. 4, the drive arm 5 extends to the z-axis direction (−) side from the first side L1 extending toward the x-axis direction (+) side and the tip of the first side L1. The second side L2, the third side L3 extending from the tip of the second side L2 to the x-axis direction (+) side, and the third side L3 extending from the tip of the third side L3 to the z-axis direction (−) side. Four sides L4, a fifth side L5 extending from the tip of the fourth side L4 to the x-axis direction (−) side, and a sixth side extending from the tip of the fifth side L5 to the z-axis direction (+) 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, and the tip is the first side It has a cross-sectional shape in which a contour is formed by the eighth side L8 connected to the base end of L1.
The first step portion 53 and the second step portion 54 have the same shape (including size). Further, the first step portion 54 and the second step portion 54 are formed rotationally symmetrically with respect to the center O of the drive arm 5. As a result, the mass of one side and the other side of the bisection point P of the drive arm 5 can be made substantially equal, and the drive arm 5 has a mass-balanced shape.

In the drive arm 5 of the present embodiment, the second step surface 532 of the first step portion 53 is provided at the same position in the z-axis direction with respect to the fourth step surface 542 of the second step portion 54. Further, the first step surface 531 of the first step portion 53 is provided away from the third step surface 541 of the second step portion 54 on the adjustment arm 7 side in the x-axis direction.
By setting it as such a structure, the intensity | strength of area | region S1 pinched | interposed into the 1st level | step-difference part 53 and the 2nd level | step-difference part 54 can fully be ensured. Therefore, the driving arm 5 can be stably vibrated obliquely. In addition, by ensuring the strength, the drive arm 5 can be effectively prevented from being twisted, and unnecessary vibrations can be effectively prevented. Further, the separation distance between the upper surface 511 and the fourth step surface 542 and the separation distance between the lower surface 512 and the second step surface 532 can be secured relatively long, and the depths of the grooves 55 and 56 described later are sufficiently deep. can do.

  Further, the drive arm 5 is formed with a first groove (groove) 55 that opens to the upper surface 511 and a second groove (groove) 56 that opens to the lower surface. The first groove 55 and the second groove 56 each extend in the y-axis direction, and are formed across the connection portion with the base portion 4. The first groove 55 has a depth in the z-axis direction and has a substantially U-shaped cross-sectional shape. Similarly, the second groove 56 has a depth in the z-axis direction and has a substantially U-shaped cross-sectional shape.

Note that the shapes of the first groove 55 and the second groove 56 are not particularly limited, and may have, for example, a rectangular cross-sectional shape.
Further, the first groove 55 and the second groove 56 are formed rotationally symmetrically with respect to the central axis O of the drive arm 5. As a result, the mass and the shape can be made substantially equal on one side and the other side of the bisection point P of the drive arm 5, and the drive arm 5 has a balanced shape in terms of inertia and mass.

Such a drive arm 5 is formed with a pair of first drive electrodes 81 and a pair of second drive electrodes 82. Specifically, one of the first drive electrodes 81 is formed in the surface of the first groove 55, and the other is formed on the inner surface of the second groove 56. One of the second drive electrodes 82 is formed across the first step surface 531, the second step surface 532, and the side surface 513, and the other is the side surface 514, the fourth step surface 542, and the third step surface 541. It is formed across.
According to such an electrode arrangement, the distance between the first and second drive electrodes 81 and 82 adjacent to each other in the x-axis direction can be reduced, so that the first and second drive electrodes 81 and 82 are generated. An electric field can be efficiently applied to the drive arm 5, whereby the drive arm 5 can be efficiently bent and vibrated with low impedance.

  The configuration of the first and second drive electrodes 81 and 82 is not particularly limited, and gold (Au), gold alloy, platinum (Pt), aluminum (Al), aluminum alloy, silver (Ag), silver alloy, Chromium (Cr), chromium alloy, copper (Cu), molybdenum (Mo), niobium (Nb), tungsten (W), iron (Fe), titanium (Ti), cobalt (Co), zinc (Zn), zirconium ( It can be formed of a metal material such as Zr) or a conductive material such as indium tin oxide (ITO).

  Among these, as the constituent material of the first and second drive electrodes 81 and 82, it is preferable to use gold (gold, gold alloy) or platinum as the main material, and gold (mainly gold) as the main material. Is more preferable. Au is suitable as an electrode material because it has excellent conductivity (low electrical resistance) and excellent resistance to oxidation. Further, Au can be easily patterned by etching as compared with Pt.

  For example, when the first and second drive electrodes 81 and 82 are made of gold and the piezoelectric substrate 3 is made of quartz, their adhesion is low. Therefore, in such a case, it is preferable to provide a base layer made of Ti, Cr or the like between the first and second drive electrodes 81 and 82 and the piezoelectric substrate 3. As a result, the adhesion between the underlayer and the drive arm 5 and the adhesion between the underlayer and the first and second drive electrodes 81 and 82 can be made excellent. As a result, it is possible to prevent the first and second drive electrodes 81 and 82 from being peeled off from the drive arm 5 and to improve the reliability of the vibration element 2.

  The shape of the drive arm 5 has been described above. However, for example, the shape as shown in FIG. Note that the shapes shown in FIG. 5 are the same except that the shapes of the first stepped portion 53 and the second stepped portion 54 (width and thickness aspect ratios) are different from the present embodiment. In FIG. 5, for convenience of explanation, auxiliary lines are provided at locations where the width of the drive arm 5 is 0%, 50%, and 100% and locations where the thickness of the drive arm 5 is 0%, 50%, and 100%. It is displayed. In FIG. 5, illustration of various electrodes and the first and second grooves 55 and 56 is omitted for convenience of explanation.

In the drive arm 5 shown in FIG. 5A, the second step surface 532 of the first step portion 53 is separated from the fourth step surface 542 of the second step portion 54 toward the upper surface 511 side in the z-axis direction. Is provided. Further, the first step surface 531 of the first step portion 53 is provided away from the third step surface 541 of the second step portion 54 on the adjustment arm 7 side in the x-axis direction.
In the driving arm 5 shown in FIG. 5B, the second step surface 532 of the first step portion 53 is separated from the fourth step surface 542 of the second step portion 54 toward the lower surface 512 in the z-axis direction. Is provided. Further, the first step surface 531 of the first step portion 53 is provided away from the third step surface 541 of the second step portion 54 on the adjustment arm 7 side in the x-axis direction.

In the drive arm 5 shown in FIG. 5C, the second step surface 532 of the first step portion 53 is separated from the fourth step surface 542 of the second step portion 54 toward the upper surface 511 side in the z-axis direction. Is provided. The first step surface 531 of the first step portion 53 is provided at the same position in the x-axis direction with respect to the third step surface 541 of the second step portion 54.
In the driving arm 5 shown in FIG. 5D, the second step surface 532 of the first step portion 53 is separated from the fourth step surface 542 of the second step portion 54 toward the upper surface 511 side in the z-axis direction. Is provided. The first step surface 531 of the first step portion 53 is provided on the opposite side to the adjustment arm 7 in the x-axis direction with respect to the third step surface 541 of the second step portion 54.
Even with the configuration as shown in FIGS. 5A to 5D, the drive arm 5 can be vibrated obliquely with a simple configuration.

(Drive arm 6)
The drive arm 6 has the same configuration (shape) as the drive arm 5 except that it is formed symmetrically with the drive arm 5 with respect to the yz plane. Therefore, the description of the configuration of the drive arm 6 is omitted.
Such a drive arm 6 is formed with a pair of first drive electrodes 81 and a pair of second drive electrodes 82. Specifically, one of the first drive electrodes 81 is formed across the first step surface 631, the second step surface 632, and the side surface 613, and the other is the side surface 614, the fourth step surface 642, and the third step surface 613. It is formed across the step surface 641. One of the second drive electrodes 82 is formed on the inner surface of the first groove 65, and the other is formed on the inner surface of the second groove 66.

(Adjustment arm 7)
The adjustment arm 7 has a constant thickness (length in the z-axis direction) and width (length in the x-axis direction) throughout the entire length direction. Such an adjustment arm 7 vibrates in accordance with the vibration of the drive arms 6 and 7.
The configuration of the vibration element 2 has been described above. Such a vibration element 2 is driven as follows.

  When an alternating voltage is applied between the first and second drive electrodes 81 and 82 by the power source 900 shown in FIG. 4, the drive arms 5 and 6 are asymmetric in cross section with respect to both the center lines L ′ and L ″, respectively. 6, the in-plane vibration causes oblique vibration as shown in Fig. 6. At this time, bending vibration in the x-axis direction of the drive arms 5 and 6 is canceled (cancelled), so the adjustment arm 7 Hardly vibrates in the x-axis direction, while the bending vibrations in the z-axis direction of the driving arms 5 and 6 are not canceled out, so that the adjusting arm 7 is z balanced so as to balance the driving arms 5 and 6. It bends and vibrates in the direction opposite to the drive arms 5 and 6 in the axial direction.

  In such vibrations, the driving arms 5 and 6 vibrate symmetrically with respect to the yz plane, and therefore, vibrations in the x-axis direction component of the bending vibrations of the driving arm 5 and bending vibrations of the vibrating arm 6. The vibration in the x-axis direction component is balanced and canceled (cancelled). Therefore, vibration in the x-axis direction is not transmitted to the adjustment arm 7, and the adjustment arm 7 hardly vibrates in the x-axis direction. In addition, since the drive arms 5 and 6 and the adjustment arm 7 bend and vibrate in the direction opposite to the z-axis direction, the vibration of the z-axis direction component of the bending vibration of the drive arms 5 and 6 and the z-axis of the adjustment arm 7 The direction vibration is balanced and canceled (cancelled). Therefore, according to the vibration element 2, vibration leakage can be effectively prevented.

  In particular, in the present embodiment, since the two drive arms 5 and 6 that vibrate obliquely are located at both ends of the base portion 4, both the out-of-plane direction and the in-plane direction are balanced (can be driven with good balance). Therefore, the drive arms 5 and 6 and the adjustment arm 7 can be vibrated more stably. Therefore, vibration leakage can be prevented more effectively. Further, since the vibration element 2 has the adjustment arm 7, the vibration (translational mobility) in the z-axis direction of the drive arms 5 and 6 is automatically canceled, so that the rotational moment is also canceled and reduced. .

[package]
Next, the package 9 that houses and fixes the vibration element 2 will be described.
As shown in FIG. 1, the package 9 includes a plate-like base substrate 91, a frame-like frame member 92, and a plate-like lid member 93. The base substrate 91, the frame member 92, and the lid member 93 are stacked in this order from the lower side to the upper side. The base substrate 91 and the frame member 92 are formed of a ceramic material or the like, which will be described later, and are joined by being integrally fired. The frame member 92 and the lid member 93 are joined by an adhesive or a brazing material. The package 9 houses the vibration element 2 in the internal space S defined by the base substrate 91, the frame member 92, and the lid member 93. In addition to the vibration element 2, an electronic component (oscillation circuit) that drives the vibration element 2 and the like can be housed in the package 9.

The constituent material of the base substrate 91 is preferably an insulating (non-conductive) material, for example, various ceramic materials such as various glass, oxide ceramics, nitride ceramics, carbide ceramics, polyimide, etc. Various resin materials such as can be used.
In addition, as the constituent material of the frame member 92 and the lid member 93, for example, the same constituent material as that of the base substrate 91, various metal materials such as Al and Cu, various glass materials, and the like can be used.

The vibration element 2 described above is fixed to the upper surface of the base substrate 91 via a fixing material 96. The fixing material 96 is made of, for example, an adhesive such as epoxy, polyimide, or silicone. For such a fixing material 96, an uncured (unsolidified) adhesive is applied onto the base substrate 91, and after placing the vibration element 2 on the adhesive, the adhesive is cured or solidified. Is formed. Thereby, the vibration element 2 is reliably fixed to the base substrate 91.
In addition, you may perform this fixation using electrically conductive adhesives, such as an epoxy type, a polyimide type, and a silicone type containing electroconductive particle.

Second Embodiment
Next, a second embodiment of the vibration device of the present invention will be described.
FIG. 7 is a cross-sectional view of the vibrating arm of the vibrating element included in the vibrating device according to the second embodiment of the invention.
Hereinafter, the second embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted.

  The second embodiment is substantially the same as the first embodiment except that the configuration of the vibration element (shape of the vibrating arm) is different. In FIG. 7, the same reference numerals are given to the same components as those in the above-described embodiment. In the present embodiment, as in the first embodiment described above, the drive arms 5 and 6 are formed symmetrically with respect to the yz plane. The description of the arm 6 is omitted.

  As shown in FIG. 7, in the drive arm 5 of the present embodiment, the first step portion 53 is configured by the yz plane, is configured by the first step surface 531 connected to the upper surface 511, the xy plane, and the side surface 513. And a fifth step surface 533 that is located between the first step surface 531 and the second step surface 532 and that connects the two surfaces 531 and 532. The fifth step surface 533 is configured by a curved surface that is inclined about the z axis with respect to the xy plane and the yz plane. That is, the first step portion 53 has a curved cross-sectional shape. In addition, although the 5th level | step difference surface 533 of this embodiment is comprised by the curved concave surface, the 5th level | step difference surface 533 may be comprised by the flat surface.

  Similarly, the second step portion 54 is configured by the yz plane, and is connected to the lower surface 512. The fourth step surface 542 is configured by the xy plane and is connected to the side surface 514. A sixth step surface 543 is located between the step surface 541 and the fourth step surface 542 and connects the three surfaces 541 and 542. Similar to the fifth step surface 533, the sixth step surface 543 is configured by a curved surface inclined about the z axis with respect to the xy plane and the yz plane. In other words, the second step portion 54 has a curved cross-sectional shape. In addition, although the 6th level | step difference surface 543 of this embodiment is comprised by the curved concave surface, the 6th level | step difference surface 543 may be comprised by the flat surface.

According to the drive arm 5 having such a configuration, the corner 57 formed by the first step surface 531 and the second step surface 532 is rounded (chamfered) by the fifth step surface 533, and the first step surface The direction of the surface continuously changes from the surface 531 to the second step surface 532. Similarly, a corner 58 formed by the third step surface 541 and the fourth step surface 542 is rounded (chamfered) by the sixth step surface 543, and the third step surface 541 to the fourth step surface 542. The direction of the surface changes continuously. Therefore, for example, compared with the first embodiment described above, the stress concentration on the corners 57 and 58 can be reduced, and the drive arm 5 can be more smoothly and obliquely vibrated. Furthermore, the formation of the second drive electrode 82 at the corners 57 and 58 can be simplified, and disconnection of the second drive electrode 82 at the corners 57 and 58 can be effectively prevented.
Also according to the second embodiment, the same operations and effects as those of the first embodiment described above can be achieved.

<Third Embodiment>
Next, a third embodiment of the vibration device of the invention will be described.
FIG. 8 is a plan view of a vibration element included in the vibration device according to the third embodiment of the invention.
Hereinafter, the third embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted.

The third embodiment is substantially the same as the first embodiment except that the configuration of the vibration element (configuration of the base) is different. In FIG. 8, the same components as those in the above-described embodiment are denoted by the same reference numerals. In FIG. 8, illustration of electrodes is omitted for convenience of explanation.
In the vibration element 2 of the present embodiment, the base 4 is configured by a plate-like main body 45 and a pair of support arms 461 and 462 extending in the x-axis direction from both sides of the main body 45. The adjustment arm 7 is connected to the main body 45, the drive arm 5 is connected to the distal end portion of the support arm 461, and the vibrating arm 6 is connected to the distal end portion of the support arm 462.
Also according to the third embodiment, the same effects as those of the first embodiment described above can be exhibited.

<Fourth embodiment>
Next, a fourth embodiment of the vibration device of the invention will be described.
FIG. 9 is a cross-sectional view of a vibration element included in the vibration device according to the fourth embodiment of the invention. FIG. 9 is a diagram corresponding to the cross-sectional view taken along the line AA of FIG. 2 described above.
Hereinafter, the fourth embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted.

The fourth embodiment is substantially the same as the first embodiment except that the vibration element is used as a gyro element. In FIG. 9, the same components as those in the first embodiment described above are denoted by the same reference numerals.
As shown in FIG. 9, the adjustment arm (detection arm) 7 of the vibration element 2 is formed with first to fourth detection electrodes 86a, 86b, 86c, 86d for detecting angular velocities. The first detection electrode 86 a is formed on the upper surface of the adjustment arm 7, the second detection electrode 86 b is formed on the lower surface of the adjustment arm 7, and the third detection electrode 86 c is one side surface of the adjustment arm 7. The fourth detection electrode 86 d is formed on the other side surface of the adjustment arm 7.

  The configuration of each of the detection electrodes 86a to 86d is not particularly limited, and gold (Au), gold alloy, platinum (Pt), aluminum (Al), aluminum alloy, silver (Ag), silver alloy, chromium (Cr). , Chromium alloy, copper (Cu), molybdenum (Mo), niobium (Nb), tungsten (W), iron (Fe), titanium (Ti), cobalt (Co), zinc (Zn), zirconium (Zr), etc. A conductive material such as a metal material or indium tin oxide (ITO) can be used.

  When the angular velocity ω about the y-axis is applied to the vibration element 2 in the state where the driving arms 5 and 6 are flexibly vibrated in the same manner as in the first embodiment, the Coriolis force acts. A new vibration A in the x-axis direction is excited on the adjustment arm (detection arm) 7. Then, the first to fourth detection electrodes 86a to 86d detect charges generated by the distortion in the x-axis direction of the adjustment arm (detection arm) 7 generated by the new vibration A, whereby the angular velocity around the y-axis is detected. ω is required.

It should be noted that the vibration in the x-axis direction can be made almost 0 (zero) by tuning, and in this case, the accuracy becomes higher.
In the present embodiment, a weight (hammer head) may be formed at the tip of each vibrating arm 5, 6, 7.
The same effect as that of the first embodiment described above can also be exhibited by the fourth embodiment.

<Fifth Embodiment>
Next, a fifth embodiment of the vibration device of the invention will be described.
FIG. 10 is a cross-sectional view of a vibration element included in the vibration device according to the fifth embodiment of the invention. FIG. 10 is a diagram corresponding to the cross-sectional view taken along the line AA of FIG. 2 described above.
Hereinafter, the fourth embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted.

The fifth embodiment is substantially the same as the first embodiment except that the vibration element is used as a gyro element. In FIG. 10, the same components as those in the first embodiment described above are denoted by the same reference numerals.
As shown in FIG. 10, two piezoelectric elements 25 and 26 for detecting angular velocity are formed side by side in the x-axis direction on the upper surface of the adjustment arm (detection arm) 7 of the vibration element 2. The piezoelectric element 25 is configured by laminating a first electrode layer 251, a piezoelectric layer 252, and a second electrode layer 253 in this order. The piezoelectric element 26 is configured by laminating a first electrode layer 261, a piezoelectric layer 262, and a second electrode layer 263 in this order. The piezoelectric layers 252 and 262 are integrally formed. The piezoelectric layers 252 and 262 do not have to be formed integrally.

When the angular velocity ω around the y-axis is applied to the vibration element 2 in a state where the drive arms 5 and 6 are flexibly vibrated in the same manner as in the first embodiment described above, Coriolis force acts, A new vibration A in the x-axis direction is excited on the adjustment arm (detection arm) 7. By detecting the distortion in the x-axis direction of the adjusting arm 7 caused by such vibration A by the two piezoelectric elements 25 and 26, the angular velocity ω about the y-axis is obtained.
Such a fifth embodiment can also exhibit the same effects as those of the first embodiment described above.
The vibration device including the vibration element of the present invention (vibration device of the present invention) has been described above.

Next, an electronic device including the vibration element of the present invention will be described in detail based on FIGS.
FIG. 11 is a perspective view illustrating a configuration of a mobile (or notebook) personal computer to which an electronic device including the resonator element according to the 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 incorporates the vibration device 1 that functions as a filter, a resonator, a reference clock, and the like.

FIG. 12 is a perspective view illustrating a configuration of a mobile phone (including PHS) to which an electronic device including the vibration element of the 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 incorporates the vibration device 1 that functions as a filter, a resonator, or the like.

FIG. 13 is a perspective view illustrating a configuration of a digital still camera to which an electronic device including the vibration element according to the 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 the vibration device 1 that functions as a filter, a resonator, and the like.

  In addition to the personal computer of FIG. 11 (mobile personal computer), the mobile phone of FIG. 12, and the digital still camera of 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 Class (eg, vehicle, aircraft) Gauges of a ship), can be applied to a flight simulator or the like.

As described above, the vibration element, the vibration device, and the electronic apparatus of 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 may be any arbitrary function having the same function. It can be replaced with that of the configuration. Further, the present invention may be a combination of any two or more configurations (features) of the above embodiments.
Moreover, you may provide the mass part (hammer head) with a larger cross-sectional area than a base end part as needed at the front-end | tip part of each vibrating arm. Thereby, a vibration element can be made smaller and the frequency of flexural vibration of the vibrating arm can be further reduced.

The vibrating element (vibrating device) of the present invention is also applied to piezoelectric oscillators such as a crystal oscillator (SPXO), a voltage controlled crystal oscillator (VCXO), a temperature compensated crystal oscillator (TCXO), and a crystal oscillator with a thermostat (OCXO). Can be applied.
Further, the shape of the drive arms 5 and 6 is not limited to the above as long as it has an asymmetric cross-sectional shape with respect to both the center lines L ′ and L ″. It may be.

  The drive arm 5 shown in FIG. 14A is located on one side (on the adjustment arm 7 side) of the upper surface 511 in the x-axis direction and opens to the side surface 513, and the lower surface 512 in the x-axis direction. Are formed on the other side (opposite side of the adjustment arm 7), and are formed with a second stepped portion 54 that opens to the side surface 514. Further, a first groove 55 that opens to the second stepped portion 54 and a lower surface 512 are formed. A second groove 56 is formed so as to be open.

The drive arm 5 shown in FIG. 14B is formed with a stepped portion 59 that is located on one side of the upper surface 511 in the x-axis direction (the side opposite to the adjustment arm 7) and opens to the side surface 514. A first groove 55 that opens to the upper surface 511 and a second groove 56 that opens to the lower surface 512 are formed.
The shape as described above has an asymmetric cross-sectional shape with respect to both the center lines L ′ and L ″ even in a state where the first and second grooves 55 and 56 are removed. In the state excluding the second grooves 55 and 56, the cross-sectional shape is symmetric with respect to both the center lines L ′ and L ″, but the center line L ′ is formed by forming the first and second grooves 55 and 56. , L ″ may be a configuration having an asymmetric cross-sectional shape. An example of such a configuration is the configuration shown in FIG.

  The drive arm 5 shown in FIG. 14C is located on one side of the upper surface 511 in the x-axis direction (on the adjustment arm 7 side) and opens to the side surface 513, and the lower surface 512 in the x-axis direction. The second step portion 54 is formed on the other side (the side opposite to the adjustment arm 7) and opens to the side surface 514. The first step portion 53 and the second step portion 54 are provided symmetrically with respect to the center line L ′. Therefore, in the configuration excluding the first and second grooves 55 and 56, the drive arm 5 is symmetric with respect to the center line L '. However, such a drive arm 5 is formed with a first groove 55 that opens to the upper surface 511 and a second groove 56 that opens to the lower surface 512, so that the drive arm 5 is centered on L ′, L ′. The cross-sectional shape is asymmetrical with respect to both lines.

DESCRIPTION OF SYMBOLS 1 ... Vibration device 2 ... Vibration element 25, 26 ... Piezoelectric element 251, 261 ... First electrode layer 252, 262 ... Piezoelectric layer 253, 263 ... Second electrode layer 3 ... Piezoelectric substrate 4 ... Base 45 ... Main body 461, 462 ... Support arm 5 ... Vibrating arm (drive arm) 511 ... Upper surface 512 ... Lower surface 513,514 ... Side 53 ... First stepped portion 531 ... First stepped portion 532 ... Second step surface 533 ... Fifth step surface 54 ... Second step portion 541 ... Third step surface 542 ... Fourth step surface 543 ... Sixth step surface 55 ... First groove 56 ... Second groove 57, 58 …… Square part 6 …… Vibrating arm (drive arm) 613, 614 …… Side surface 631 …… First step surface 632 …… Second step surface 641 …… Third step surface 642 …… Four step surface 65… ... 1st groove 66 ... 2nd groove 7 ... Vibrating arm (detection arm) 81 ... 1st Drive electrode 82 …… Second drive electrode 86a, 86b, 86c, 86d …… Detection electrode 9 …… Package 91 …… Base substrate 92 …… Frame member 93 …… Lid member 96 …… Fixing material 900… Power source 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 Television monitor 1440 Personal computer P Bisection point S Internal Space L1 …… First side L2 …… Second side L3 …… 3rd side L4 …… 4th side L5 …… 5th side L6 …… 6th side L7 …… 7th side L8 …… 8th side L ′, L ″ …… Center line S1 …… Area

Claims (10)

The base,
A first drive arm and a second drive arm extending from the base;
A vibration element comprising:
A direction in which the first drive arm and the second drive arm are arranged is a first direction, a direction in which the first drive arm is extended is a second direction, and the first direction and the second direction are When the direction perpendicular to the surface formed by the direction is the third direction,
The first drive arm has a first surface and a second surface in a front-back relationship with the first surface, and a first side surface and a second side surface in a front-back relationship with the first side surface,
The second drive arm has a third surface and a fourth surface in a front-back relationship with the third surface, and a third side surface and a fourth side surface in a front-back relationship with the third side surface,
Regarding the first direction, the first side surface, the second side surface, the third side surface, and the fourth side surface are arranged in this order,
With respect to the third direction, the first surface and the third surface are on the same side, and the second surface and the fourth surface are on the same side,
A first groove is provided on at least one of the first surface and the second surface;
A second groove is provided on at least one of the third surface and the fourth surface;
A first step portion is provided between the first surface and the second side surface;
A second step portion is provided between the third surface and the third side surface ;
At least a part of the first drive arm has an asymmetric shape with respect to the center line in the first direction and the center line in the third direction in a cross section perpendicular to the second direction,
At least a part of the second drive arm is a vibration element having an asymmetric shape with respect to a center line in the first direction and a center line in the third direction in a cross section perpendicular to the second direction . The base,
A first drive arm and a second drive arm extending from the base;
A vibration element comprising:
A direction in which the first drive arm and the second drive arm are arranged is a first direction, a direction in which the first drive arm is extended is a second direction, and the first direction and the second direction are When the direction perpendicular to the surface formed by the direction is the third direction,
The first drive arm has a first surface and a second surface in a front-back relationship with the first surface, and a first side surface and a second side surface in a front-back relationship with the first side surface,
The second drive arm has a third surface and a fourth surface in a front-back relationship with the third surface, and a third side surface and a fourth side surface in a front-back relationship with the third side surface,
Regarding the first direction, the first side surface, the second side surface, the third side surface, and the fourth side surface are arranged in this order,
With respect to the third direction, the first surface and the third surface are on the same side, and the second surface and the fourth surface are on the same side,
A first groove is provided on at least one of the first surface and the second surface;
A second groove is provided on at least one of the third surface and the fourth surface;
A first step is provided between the second surface and the first side surface;
A second step portion is provided between the fourth surface and the fourth side surface ;
At least a part of the first drive arm has an asymmetric shape with respect to the center line in the first direction and the center line in the third direction in a cross section perpendicular to the second direction,
At least a part of the second drive arm is a vibration element having an asymmetric shape with respect to a center line in the first direction and a center line in the third direction in a cross section perpendicular to the second direction .   The first groove portion is provided on the first surface and the second surface, and the second groove portion is provided on the third surface and the fourth surface. The vibration element described.   The first step portion is provided on the second side surface side of the first surface and the first side surface side of the second surface, and the second step portion is the third side surface of the third surface. The vibration element according to claim 1, wherein the vibration element is provided on a side and the fourth side surface of the fourth surface.   5. The vibration element according to claim 1, wherein at least one of the first step portion and the second step portion has a cross-sectional shape that is a polygonal shape or a curved shape.   6. The vibration element according to claim 1, wherein electrodes are provided on an inner wall surface of the groove and a surface of the stepped portion.   The first drive arm and the second drive arm each include a vibration component in a normal direction of the first surface and a vibration component in a normal direction of the first side surface. The vibration element according to one item. The vibration element according to any one of claims 1 to 7,
And a package containing the vibration element. The vibration element according to any one of claims 1 to 7,
A gyro sensor comprising: a package housing the vibration element.   The electronic device provided with the vibration element as described in any one of Claims 1 thru | or 7.

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