JP2012142666A - Vibration device and electronic apparatus - Google Patents

Abstract

An object of the present invention is to provide a vibrating device having a vibrating body that can reduce unnecessary vibration modes and can be driven efficiently.
A vibrating body 2 of a vibrating device 1 includes a base 27 and two vibrating arms 28 extending from the base 27 in the Y-axis direction and arranged side by side in the X-axis direction orthogonal to the Y-axis direction. 29 and excitation electrodes 221, 222, 223, 224, 231, 232, 233, 234 provided on the respective vibrating arms 28, 29 and exciting the vibrating arms 28, 29 by energization, 222, 231 and 232 are partially formed with a plurality of fine holes penetrating in the thickness direction thereof, whereby the vibration characteristics of the vibrating arms 28 and 29 are adjusted.
[Selection] Figure 1

Description

  The present invention relates to a vibration device having a vibration body and an electronic apparatus including the vibration device.

Conventionally, as a vibrating body used in a vibrating device, a tuning fork type having a plurality of vibrating arms is known.
For example, a vibrating body described in Patent Document 1 includes a base, two vibrating arms extending from the base so as to be parallel to each other, a pair of excitation electrodes and a pair of excitation electrodes provided on each vibrating arm. Side excitation electrodes. In such a vibrating body, the base and each vibrating arm are made of quartz, and an electric field is applied between a pair of excitation electrodes and a pair of side excitation electrodes, thereby vibrating each vibrating arm. Let

  An oscillation signal generated by such a vibrator includes many signal components having a desired fundamental frequency, but also includes signal components having higher harmonic frequencies in addition to the component. When the CI value (crystal impedance) of the harmonic (higher order vibration mode) of the vibrating body is divided by the CI value of the fundamental wave (fundamental vibration mode), that is, when the CI value ratio is small, the harmonic signal that is a noise component There is a risk that the components will become large and the equipment will become abnormal.

  Therefore, in the vibrating body described in Patent Document 1, the CI value ratio is increased by making the length of the excitation electrode about half that of the vibrating arm.

JP 2002-280870 A

However, if the length of the excitation electrode in the vibrating body is about half that of the vibrating arm, the CI value of the fundamental wave increases. Therefore, the vibrator described in Patent Document 1 has a problem that it cannot be driven efficiently.
An object of the present invention is to provide a vibrating device having a vibrating body that can reduce unnecessary vibration modes and can be driven efficiently, and an electronic apparatus including the vibrating device.

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 vibrating device of the present invention includes a vibrating body and a drive circuit unit that drives the vibrating body,
The vibrating body includes a base,
A plurality of resonating arms extending in the first direction from the base and arranged side by side in a second direction orthogonal to the first direction;
A pair of excitation electrodes provided on each of the vibrating arms and configured to excite the vibrating arms by energization;
A plurality of holes penetrating in the thickness direction are partially formed in at least one excitation electrode of the pair of excitation electrodes.

As a result, the vibrating device according to the present invention increases the length of the excitation electrode on the vibrating arm in the first direction (the extending direction of the vibrating arm) while generating an electric field (vibrating arm) between the pair of exciting electrodes. The vibration characteristic of the vibrating arm can be adjusted by reducing the density of the electric field that contributes to the unnecessary vibration mode.
Therefore, the vibration device can reduce unnecessary vibration modes and can be driven efficiently.

[Application Example 2]
In the vibrating device according to the application example described above, it is preferable that the plurality of holes are formed unevenly in the first direction in the at least one excitation electrode.
Thereby, the vibrating device can adjust the vibration characteristic of the vibrating arm by changing the ratio between the CI value of the harmonic (higher order vibration mode) and the CI value of the fundamental wave (fundamental vibration mode).

[Application Example 3]
In the vibrating device according to the application example described above, it is preferable that the plurality of holes are unevenly distributed in a central portion of the excitation electrode in the first direction of the vibrating arm.
Accordingly, the vibration device can reduce the CI value of the fundamental wave, increase the CI value of the harmonic, and increase the CI value ratio (harmonic CI value / fundamental CI value).

[Application Example 4]
In the vibrating device according to the application example described above, the ratio of the area occupied by the hole per unit area of the excitation electrode is gradually decreased from the central portion in the first direction of the vibrating arm toward the distal end side. Preferably it is.
Thereby, the vibration device can increase the CI value of harmonics and increase the CI value ratio (harmonic CI value / fundamental CI value) while making the excitation of the vibrating arm smooth and efficient.

[Application Example 5]
In the vibrating device according to the application example described above, the ratio of the area occupied by the hole per unit area of the excitation electrode is gradually decreased from the central portion in the first direction of the vibrating arm toward the proximal end side. Preferably it is.
Thereby, the vibration device can increase the CI value of harmonics and increase the CI value ratio (harmonic CI value / fundamental CI value) while making the excitation of the vibrating arm smooth and efficient.

[Application Example 6]
In the vibrating device according to the application example, when the length of the vibrating arm in the first direction is L1, and the length of the excitation electrode on the vibrating arm in the first direction is L2, 0 is obtained. It is preferable that the relationship of 5 <L2 / L1 <1 is satisfied.
As a result, the vibrating device can reduce the CI value of the fundamental wave and efficiently excite the vibrating arm.

[Application Example 7]
The vibrating device of the present invention includes a vibrating body and a drive circuit unit that drives the vibrating body,
The vibrating body includes a base,
A plurality of resonating arms extending in the first direction from the base and arranged side by side in a second direction orthogonal to the first direction;
A piezoelectric element that is provided on each vibrating arm and expands and contracts by energization to vibrate the vibrating arm;
The piezoelectric element includes a first electrode layer, a second electrode layer, and a piezoelectric layer located between the first electrode layer and the second electrode layer,
A plurality of holes penetrating in the thickness direction are partially formed in at least one of the first electrode layer, the piezoelectric layer, and the second electrode layer. And

As a result, the vibration device of the present invention increases the length of the piezoelectric element on the vibrating arm in the first direction, while generating an electric field (piezoelectric) between the first electrode layer and the second electrode layer. The vibration characteristics of the vibrating arm can be adjusted by reducing the density of the electric field contributing to an unnecessary vibration mode among the electric field applied to the body layer.
Therefore, the vibration device can reduce unnecessary vibration modes and can be driven efficiently.

[Application Example 8]
In the vibrating device according to the application example, the number of the vibrating arms is three or more, and two adjacent in the third direction orthogonal to the first direction and the second direction due to expansion and contraction of the piezoelectric element. It is preferable that the two vibrating arms bend and vibrate in opposite directions.
Thereby, the vibration device can bend and vibrate three or more vibration arms in the third direction while preventing vibration leakage.

[Application Example 9]
In the vibrating device according to the application example, it is preferable that each of the holes has a circular shape in a plan view.
Thereby, the vibrating device can adjust the vibrating arm to a desired vibration characteristic relatively easily.

[Application Example 10]
In the vibrating device according to the application example, it is preferable that an average diameter of the plurality of holes is 0.01 to 100 μm.
Thereby, the vibrating device can adjust the vibrating arm to a desired vibration characteristic while making the formation of the plurality of holes relatively easy.

[Application Example 11]
In the vibrating device according to the application example, it is preferable that each of the holes has a slit shape in a plan view.
Thereby, the vibrating device can adjust the vibrating arm to a desired vibration characteristic relatively easily.

[Application Example 12]
In the vibrating device according to the application example described above, it is preferable that each of the slit-like holes extends in the second direction.
Thereby, the vibrating device can adjust the vibrating arm to a desired vibration characteristic relatively easily.

[Application Example 13]
In the vibrating device according to the application example described above, it is preferable that the width of the slit-shaped hole is 0.01 to 100 μm.
As a result, the vibrating device can adjust the vibrating arm to desired vibration characteristics while making the formation of the plurality of holes relatively easy.

[Application Example 14]
An electronic apparatus according to the present invention includes the vibration device according to the application example described above.
Thereby, the electronic device of this invention can reduce an unnecessary vibration mode, and can drive it efficiently.

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 vibrating body with which the vibration device shown in FIG. 1 was equipped. It is the sectional view on the AA line in FIG. FIG. 2A is a graph showing the relationship between the position of the vibrating body in the extending direction (Y-axis direction) of the vibrating body shown in FIG. 2 and the displacement amount and distortion of the basic vibration mode of the vibrating arm; FIG. 4 is a graph showing the relationship between the position of the vibrating body in the extending direction (Y-axis direction) of the vibrating body shown in FIG. 2 and the amount of displacement and strain in the higher-order vibration mode of the vibrating arm. 3 is a graph showing the relationship between the position of the vibrating arm in the extending direction (Y-axis direction) in the vibrating body shown in FIG. 2 and the ratio of the area occupied by the excitation electrode per unit area on the vibrating arm. It is a top view which shows the vibrating body with which the vibrating device which concerns on 2nd Embodiment of this invention was equipped. FIG. 7 is a side view of the vibrating body shown in FIG. 6. It is a top view which shows the vibrating body with which the vibrating device which concerns on 3rd Embodiment of this invention was equipped. It is a side view of the vibrating body shown in FIG. It is a bottom view which shows the vibrating body with which the vibrating device which concerns on 4th Embodiment of this invention was equipped. It is the sectional view on the AA line in FIG. It is the figure which abbreviate | omitted illustration of each 2nd electrode layer with which the vibrating body was provided in FIG. FIG. 11 is a diagram in which illustration of each second electrode layer and each piezoelectric layer provided in the vibrating body in FIG. 10 is omitted. It is a perspective view for demonstrating operation | movement of the vibrating body shown in FIG. The perspective view which shows the outline of the mobile telephone as an example of an electronic device. The circuit block diagram of a mobile telephone. The perspective view which shows the outline of the personal computer as an example of an electronic device.

Hereinafter, a vibrating device and an electronic apparatus according to the present 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 body provided in the vibrating device shown in FIG. 1, and FIG. 3 is A in FIG. FIG. 4A is a cross-sectional view taken along the line A, and shows the position of the vibrating body in the extending direction (Y-axis direction) of the vibrating body shown in FIG. 2 and the displacement amount and distortion of the basic vibration mode of the vibrating arm. FIG. 4B is a graph showing the relationship between the position of the vibrating body shown in FIG. 2 in the extending direction (Y-axis direction) of the vibrating arm and the displacement amount and distortion of the higher-order vibration mode of the vibrating arm. FIG. 5 is a graph showing the relationship between the position of the vibrating arm in the extending direction (Y-axis direction) in the vibrating body shown in FIG. 2 and the ratio of the area occupied by the excitation electrode per unit area on the vibrating arm. It is a graph which shows a relationship.

In each of FIGS. 1 to 3, for convenience of explanation, an X axis, a Y axis, and a Z axis are illustrated as three axes orthogonal to each other. In the following, the direction parallel to the X axis (second direction) is the “X axis direction”, the direction parallel to the Y axis (first direction) is the “Y axis direction”, and the direction is parallel to the Z axis ( The third direction) is referred to as “Z-axis direction”. 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 vibrating device 1 shown in FIG. 1 includes a vibrating body 2, a package 3 that houses the vibrating body 2, and a drive circuit unit 50 that drives the vibrating body 2, and functions as a so-called oscillator.

Hereinafter, each part which comprises the vibration device 1 is demonstrated in detail sequentially.
(Vibrating body)
First, the vibrating body 2 will be described.
The vibrating body 2 is a tuning fork type vibrating body as shown in FIG. The vibrating body 2 includes a vibration substrate 21, excitation electrode groups 22 and 23 and connection electrodes 41 and 42 provided on the vibration substrate 21.

The vibration substrate 21 includes a base 27 and two (one pair) vibration arms 28 and 29.
The vibration substrate 21 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 vibration substrate 21 is preferably quartz. When the vibration substrate 21 is made of quartz, the vibration characteristics of the vibration substrate 21 can be made excellent. Further, the vibration substrate 21 can be formed with high dimensional accuracy by etching.

In such a vibration substrate 21, the base 27 has a square shape including a pair of sides parallel to the X-axis direction and a pair of sides parallel to the Y-axis direction in plan view. . In addition, the planar view shape of the base 27 is not limited to this.
Two vibrating arms 28 and 29 are connected to one side of the base portion 27 parallel to the X-axis direction.

The vibrating arms 28 and 29 are connected to both end portions of the base portion 27 in the X-axis direction.
The two vibrating arms 28 and 29 are provided to extend from the base 27 so as to be parallel to each other. In other words, the two vibrating arms 28 and 29 extend from the base portion 27 in the Y-axis direction and are arranged side by side in the X-axis direction.
Each of the vibrating arms 28 and 29 has a longitudinal shape, and an end portion (base end portion) on the base portion 27 side is a fixed end, and an end portion (tip end portion) opposite to the base portion 27 is a free end.

The vibrating arms 28 and 29 are formed to have the same width. Thereby, when the vibrating arms 28 and 29 are vibrated in opposite directions (in opposite phases), vibration leakage can be reduced.
In addition, the vibrating arms 28 and 29 have a constant width over the entire area in the longitudinal direction. Note that, if necessary, a mass portion (hammer head) having a larger cross-sectional area than the base end portion may be provided at each distal end portion of the vibrating arms 28 and 29. In this case, the vibrating body 2 can be made smaller, and the vibration frequency of the vibrating arms 28 and 29 can be further reduced.
Further, the cross section of each vibrating arm 28, 29 is rectangular. The cross-sectional shape of each vibrating arm 28, 29 is not limited to a quadrangle. For example, by forming grooves along the Y-axis direction on the upper surface and the lower surface of each vibrating arm 28, 29, an H-shape is formed. It may be done.

As shown in FIG. 3, an excitation electrode group 22 is provided on such a vibrating arm 28, and an excitation electrode group 23 is provided on the vibrating arm 29.
The excitation electrode group 22 has a function of bending vibration (excitation) of the vibrating arm 28 by energization. The excitation electrode group 23 has a function of bending vibration (excitation) of the vibrating arm 29 by energization. Such an excitation electrode group 22 includes the excitation electrode 221 provided on the upper surface of the vibrating arm 28, the excitation electrode 222 provided on the lower surface of the vibrating arm 28, and one side surface of the vibrating arm 28. The excitation electrode 223 provided and the excitation electrode 224 provided on the other side surface of the vibrating arm 28 are configured.

The excitation electrodes 221, 222, 223, and 224 respectively extend from the vicinity of the proximal end of the vibrating arm 28 to the vicinity of the distal end portion. Further, the widths of the excitation electrodes 221, 222, 223, and 224 in the X-axis direction are constant over the entire region in the Y-axis direction.
In particular, as shown in FIG. 2, the excitation electrode 221 has a plurality of fine holes 2211 penetrating in the thickness direction. Although not shown, the excitation electrode 222 is similarly formed with a plurality of fine holes penetrating in the thickness direction. The vibration characteristics of the vibrating arm 28 are adjusted by forming such a plurality of holes in the excitation electrodes 221 and 222, respectively. The adjustment of the vibration characteristics of the vibrating arm 28 will be described in detail later.

Similarly, the excitation electrode group 23 includes the excitation electrode 231 provided on the upper surface of the vibration arm 29 described above, the excitation electrode 232 provided on the lower surface of the vibration arm 29, and one side surface of the vibration arm 29. The excitation electrode 233 provided and the excitation electrode 234 provided on the other side surface of the vibrating arm 29 are configured.
The excitation electrodes 231, 232, 233, and 234 extend from the vicinity of the proximal end of the vibrating arm 29 to the vicinity of the distal end portion, respectively. Further, the widths of the excitation electrodes 231, 232, 233, and 234 in the X-axis direction are constant over the entire region in the Y-axis direction.

  In particular, as shown in FIG. 2, the excitation electrode 231 has a plurality of fine holes 2311 penetrating in the thickness direction. Although not shown, the excitation electrode 232 is also formed with a plurality of fine holes penetrating in the thickness direction. The vibration characteristics of the vibrating arm 29 are adjusted by forming such a plurality of holes in the excitation electrodes 231 and 232, respectively. Such excitation electrodes 221, 222, 233, and 234 are electrically connected to the connection electrode 41 via wiring not shown. Further, the excitation electrodes 223, 224, 231 and 232 are electrically connected to the connection electrode 42 via a wiring (not shown).

  In the vibrating body 2 having such a configuration, when a voltage is applied between the connection electrode 41 and the connection electrode 42, the excitation electrodes 221, 222, 233, and 234 and the excitation electrodes 223, 224, 231, and 232 have opposite polarities. In this manner, voltages in the direction including the X-axis direction component are applied to the vibrating arms 28 and 29, respectively. The vibrating arms 28 and 29 can be flexibly vibrated at a certain frequency (resonance frequency) due to the inverse piezoelectric effect of the piezoelectric material. At this time, the vibrating arms 28 and 29 are flexibly vibrated in directions opposite to each other.

Further, when the vibrating arms 28 and 29 are bent and vibrated, a voltage is generated between the connection electrodes 41 and 42 at a certain frequency due to the piezoelectric effect of the piezoelectric material. Utilizing these properties, the vibrating body 2 can generate an electrical signal that vibrates at a resonance frequency.
Such excitation electrode groups 22 and 23, connection electrodes 41 and 42, and wiring (not shown) are conductive materials such as aluminum, aluminum alloy, silver, silver alloy, chromium, chromium alloy, gold, and gold-chrome laminated film, respectively. It can be formed of a metal material having excellent properties.

Examples of methods for forming these electrodes include physical film formation methods such as sputtering and vacuum deposition, chemical vapor deposition methods such as CVD, and various coating methods such as an ink jet method.
Here, the adjustment of the vibration characteristics of the vibrating arm 28 will be described in detail. In the following, the adjustment of the vibration characteristics of the vibration arm 28 will be described as a representative, but the same applies to the adjustment of the vibration characteristics of the vibration arm 29.

As described above, the excitation electrode 221 has a plurality of fine holes 2211 penetrating in the thickness direction. Although not shown, the excitation electrode 222 is similarly formed with a plurality of fine holes penetrating in the thickness direction.
In particular, the excitation electrode 221 is partially formed with a plurality of fine holes 2211 penetrating in the thickness direction. Further, in correspondence with the plurality of holes 2211 (similar to the plurality of holes 2211), the excitation electrode 222 partially has a plurality of fine holes (not shown) penetrating in the thickness direction. Is formed.

  As a result, the excitation electrode 221 and the excitation electrodes 223 and 224 are increased while increasing the length of each excitation electrode 221, 222, 223, and 224 on the vibration arm 28 in the Y-axis direction (the extending direction of the vibration arm 28). Between the excitation electrode 222 and the excitation electrodes 223 and 224 (electric field applied to the vibration arm 28) is reduced, and the density of the electric field contributing to an unnecessary vibration mode is reduced. The vibration characteristics can be adjusted.

For this reason, the vibrator 2 can be driven efficiently by reducing unnecessary vibration modes.
In the present embodiment, the excitation electrodes 223 and 224 are not formed with a plurality of holes such as the plurality of holes 2211. That is, the excitation electrodes 223 and 224 are configured as a dense layer without being patterned on the inside of the contour. Thereby, manufacture of the vibrating body 2 can be made easy.

Hereinafter, the relationship between the plurality of holes formed in the excitation electrodes 221 and 222 and the vibration characteristics of the vibrating arm 28 will be described in detail. In the following description, the excitation electrode 221 is representatively described, but the same applies to the excitation electrode 222.
More specifically, the vibrating arm 28 of the vibrating body 2 configured as described above is excited at the frequency of a desired fundamental vibration mode (fundamental wave). Even a higher-order vibration mode frequency different from the mode is excited.
As shown in FIG. 4A, the displacement amount of the vibration arm 28 in the basic vibration mode (the displacement amount of the neutral line) increases from the proximal end side to the distal end side of the vibration arm 28. In addition, the distortion caused by the displacement of the vibrating arm 28 basic vibration mode decreases from the proximal end side to the distal end side of the vibrating arm 28. In FIG. 4, the vertical axis indicates the relative value of the displacement amount, charge, and strain of the vibrating arm 28. The horizontal axis indicates the position of the vibrating arm 28 in the Y-axis direction. A value of 0 on the horizontal axis corresponds to an end (base end) on the base 27 side of the vibrating arm 28, and L1 on the horizontal axis. Corresponds to the end (tip) of the vibrating arm 28 opposite to the base 27.

  On the other hand, as shown in FIG. 4B, the displacement amount of the higher-order vibration mode of the vibrating arm 28 (the displacement amount of the neutral line) is from the proximal end side to the distal end side of the vibrating arm 28 to the vicinity of the center portion. After increasing, it decreases to near the tip and then increases. Further, the distortion caused by the displacement of the higher-order vibration mode of the vibrating arm 28 increases from the proximal end side to the distal end side of the vibrating arm 28 to the vicinity of the center portion and then decreases.

From this, it can be seen that in the central portion of the vibrating arm 28 in the Y-axis direction, the excitation in the fundamental vibration mode is not so large, but the excitation in the higher-order vibration mode is large. Further, the excitation in the higher-order vibration mode is larger at the center portion than the end portion of the vibrating arm 28 in the Y-axis direction.
Therefore, the plurality of holes 2211 are unevenly distributed (partially formed) in the middle of the excitation electrode 221 in the extending direction of the vibrating arm 28. More specifically, the plurality of holes 2211 are unevenly distributed (partially formed) at a portion corresponding to the central portion of the excitation electrode 221 in the extending direction (Y-axis direction) of the vibrating arm 28. ).

By making the plurality of holes 2211 unevenly distributed in the middle of the excitation electrode 221 in the extending direction of the vibrating arm 28, the ratio between the CI value of the harmonic (higher order vibration mode) and the CI value of the fundamental wave is changed, The vibration characteristics of the vibrating arm 28 can be adjusted.
In particular, the plurality of holes 2211 are unevenly distributed in a portion of the excitation electrode 221 corresponding to the central portion in the extending direction of the vibrating arm 28 (Y-axis direction), whereby the length L2 of the excitation electrode 221 in the Y-axis direction. Even if the length is increased, the excitation of the higher-order vibration mode of the vibrating arm 28 can be significantly suppressed, and the CI value of the higher-order vibration mode of the vibrating body 2 can be increased. That is, the CI value of the fundamental wave can be reduced and the CI value of the harmonic can be increased to increase the CI value ratio (harmonic CI value / fundamental CI value).

  When the length of the vibrating arm 28 in the extending direction (Y-axis direction) is L1, and the length of the excitation electrode 221 in the same direction on the vibrating arm 28 is L2, 0.5 <L2 / L1. <1 relationship is satisfied. Thereby, the CI value of the fundamental wave can be reduced, and the excitation of the vibrating arm 28 can be made efficient. From this point of view, the lengths L1 and L2 particularly preferably satisfy the relationship of 0.6 <L2 / L1 <0.9, and the relationship of 0.7 <L2 / L1 <0.8. It is more preferable to satisfy.

On the other hand, when L2 / L1 is less than the lower limit value, it is difficult to sufficiently reduce the CI value of the fundamental wave depending on the shape, width, length, and the like of the vibrating arm 28. On the other hand, when L2 / L1 exceeds the upper limit, it is difficult to increase the CI value of the harmonic depending on the shape, width, length, and the like of the vibrating arm 28.
The ratio of the area occupied by the holes 2211 per unit area of the excitation electrode 221 (hereinafter also referred to as “hole existence ratio”) is from the center to the tip side in the extending direction (Y-axis direction) of the vibrating arm 28 and Each gradually decreases toward the base end side. In other words, as shown in FIG. 5, the ratio of the area occupied by the electrode in each region obtained by dividing the excitation electrode 221 for each unit length in the Y-axis direction (hereinafter also referred to as “electrode existence ratio”) is the vibration The arm 28 gradually increases from the center in the extending direction (Y-axis direction) toward the distal end side and the proximal end side. Thereby, it is possible to increase the CI value of harmonics and increase the CI value ratio (harmonic CI value / fundamental CI value) while making excitation of the vibrating arm 28 smooth and efficient.

In addition, when the hole existence ratio increases or decreases according to the magnitude of the distortion generated in the higher-order vibration mode shown in FIG. 4B, the excitation in the higher-order vibration mode can be more reliably reduced. it can.
In addition, the hole existence ratio is increased or decreased according to the difference between the magnitude of the distortion generated in the higher-order vibration mode shown in FIG. 4B and the magnitude of the distortion generated in the basic vibration mode shown in FIG. If so, it is possible to effectively reduce the excitation in the higher-order vibration mode while enhancing the excitation in the fundamental vibration mode.

Each hole 2211 has a circular shape in plan view. Thereby, the vibrating arm 28 can be adjusted relatively easily to a desired vibration characteristic. Each hole 2211 may have a substantially circular shape close to a circle.
In the present embodiment, the plurality of holes 2211 are formed to have the same planar view shape and area. Therefore, the hole existence ratio (electrode existence ratio) as described above is realized by changing the interval between the holes 2211 according to the position in the Y-axis direction.

Note that the plurality of holes 2211 may be formed to have different planar shapes and areas. In this case, even if the interval between the holes 2211 is constant, the hole presence ratio (electrode presence ratio) as described above can be obtained by changing the planar view shape and area of each hole 2211 according to the position in the Y-axis direction. Can be realized.
The average diameter of the plurality of holes 2211 is preferably 0.01 to 100 μm, more preferably 0.1 to 10 μm. Thereby, the vibrating arm 28 can be adjusted to desired vibration characteristics while making the formation of the plurality of holes 2211 relatively easy.

  On the other hand, when the average diameter is less than the lower limit, it may be difficult to form the plurality of holes 2211 depending on the constituent material, thickness, and the like of the excitation electrode 221. On the other hand, when the average diameter exceeds the upper limit, it is difficult to increase the area occupation ratio of the holes 2211 in a desired region. Further, depending on the range or position where the excitation electrode 221 is formed, the vibration characteristics of the vibrating arm 28 may be adversely affected.

  In addition, when the excitation electrode 221 is viewed in plan, the ratio of the area occupied by the plurality of holes 2211 to the entire excitation electrode 221 (area occupation ratio) is determined according to the vibration characteristics of the vibration arm 28 to be obtained. Is preferably 0.1 to 0.5, and more preferably 0.1 to 0.4. In other words, when the excitation electrode 221 is viewed in plan, the ratio of the area occupied by the electrode in the region surrounded by the outline of the excitation electrode 221 is preferably 0.5 to 0.9, and 0.6 More preferably, it is -0.9. Thereby, it is possible to adjust the vibrating arm 28 to desired vibration characteristics while preventing conduction failure such as disconnection of the excitation electrode 221 that is likely to occur when the ratio of the area occupied by the electrode is reduced.

(package)
Next, the package 3 that houses and fixes the vibrating body 2 will be described.
As illustrated in FIG. 1, the package 3 includes a plate-like base substrate 31, a frame-like frame member 32, and a plate-like lid member 33. The base substrate 31, the frame member 32, and the lid member 33 are laminated in this order from the lower side to the upper side. The base substrate 31 and the frame member 32 are formed of a ceramic material or the like described later, and are integrally formed with each other. Joined by firing. The frame member 32 and the lid member 33 are joined by an adhesive or a brazing material. The package 3 houses the vibrating body 2 in an internal space 37 defined by the base substrate 31, the frame member 32, and the lid member 33. In addition to the vibrating body 2, a drive circuit unit 50 that drives the vibrating body 2 is housed in the package 3. The drive circuit unit 50 is a semiconductor circuit element including an oscillation circuit that oscillates the vibrating body 2 and a temperature compensation circuit. In this case, the drive circuit unit 50 is an IC chip.

  As the constituent material of the base substrate 31, those having insulating properties (non-conductive) are preferable. For example, various glass materials, various ceramic materials such as oxide ceramics, nitride ceramics, carbide ceramics, polyimide, etc. Various resin materials can be used. In addition, as the constituent material of the frame member 32 and the lid member 33, for example, the same constituent material as that of the base substrate 31, various metal materials such as Al and Cu, various glass materials, and the like can be used. In particular, when a material having light transmissivity such as a glass material is used as the constituent material of the lid member 33, if a metal cover (not shown) is formed in advance on the vibrating body 2, the vibrating body 2 is packaged. Even after being housed in 3, by irradiating the metal coating part with a laser through the lid member 33 and removing the metal coating part to reduce the mass of the vibrator 2 (by a mass reduction method ), The frequency of the vibrating body 2 can be adjusted.

  The base substrate 31 has a step on the surface on the inner space 37 side, and a pair of mount electrodes 35 a and 35 b are formed on the upper step surface so as to be exposed to the inner space 37. On the mount electrodes 35a and 35b, conductive adhesives 36a and 36b, such as epoxy, polyimide, and silicone, containing conductive particles are respectively applied (stacked). The above-described vibrating body 2 is placed on the conductive adhesives 36a and 36b. Thereby, the vibrating body 2 (base portion 27) is securely fixed to the mount electrodes 35a and 35b (base substrate 31).

  On the other hand, a drive circuit unit 50 is placed on the lower step surface of the base substrate 31, and the drive circuit unit 50 is electrically connected to the drive circuit unit 50 via a metal wire (bonding wire) 55. A plurality of circuit connection terminals 56 are provided. In this case, four external terminals 34a, 34b, 34c, and 34d are provided on the lower surface of the base substrate 31. Thus, the mount electrodes 35a and 35b, the circuit connection terminal 56, and the external terminals 34a to 34d provided in the package 3 are connected to each other by an intra-layer wiring such as a lead wiring or a through hole (not shown). ing.

Such circuit connection terminal 56, mount electrodes 35a and 35b, and external terminals 34a to 34d can be formed, for example, by applying gold plating to an underlying layer of tungsten and nickel plating.
The mount electrodes 35a and 35b and the connection electrodes 41 and 42 may be electrically connected through a metal wire (bonding wire) formed by, for example, a wire bonding technique. In this case, the vibrating body 2 can be fixed to the base substrate 31 via an adhesive having no conductivity instead of the conductive adhesives 36a and 36b. Further, when an electronic component is accommodated in the package 3, the lower surface of the base substrate 31 may be used to check the characteristics of the electronic component and various information in the electronic component (for example, temperature compensation information of the vibration device) as necessary. A write terminal for rewriting (adjustment) may be formed.

According to the first embodiment as described above, a plurality of fine holes penetrating in the thickness direction are formed in the middle of the excitation electrodes 221 and 222 in the longitudinal direction (Y-axis direction). While increasing the length of each excitation electrode 221, 222, 223, 224 on the vibrating arm 28 in the Y-axis direction (extending direction of the vibrating arm 28), between the excitation electrode 221 and the excitation electrodes 223, 224, and Of the electric fields generated between the excitation electrode 222 and the excitation electrodes 223 and 224 (the electric field applied to the vibrating arm 28), the density of the electric field contributing to an unnecessary vibration mode is reduced, and the vibration characteristics of the vibrating arm 28 are reduced. Can be adjusted.
For this reason, the vibrator 2 can be driven efficiently by reducing unnecessary vibration modes.

Second Embodiment
Next, a second embodiment of the vibration device of the present invention will be described.
FIG. 6 is a top view showing a vibrating body provided in a vibrating device according to the second embodiment of the present invention, and FIG. 7 is a side view of the vibrating body shown in FIG.
Hereinafter, the vibration device according to 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 vibrating device according to the second embodiment is substantially the same as the first embodiment except that a plurality of fine holes are also formed in the excitation electrode provided on each side surface of each vibrating arm. 6 and 7, the same reference numerals are given to the same configurations as those of the above-described embodiment.
The vibrating body 2A of the vibrating device of the present embodiment includes excitation electrode groups 22A and 23A provided on the vibrating substrate 21, as shown in FIG.

The excitation electrode group 22 </ b> A is provided on the vibrating arm 28, and the excitation electrode group 23 </ b> A is provided on the vibrating arm 29.
Such an excitation electrode group 22 </ b> A includes the excitation electrode 221 provided on the upper surface of the vibrating arm 28, the excitation electrode 222 provided on the lower surface of the vibrating arm 28, and one side surface of the vibrating arm 28. The excitation electrode 223 </ b> A provided and the excitation electrode 224 </ b> A provided on the other side surface of the vibrating arm 28 are configured.

The excitation electrode group 23 </ b> A is provided on one side surface of the vibration arm 29, the excitation electrode 231 provided on the upper surface of the vibration arm 29, the excitation electrode 232 provided on the lower surface of the vibration arm 29. And the excitation electrode 234A provided on the other side surface of the vibrating arm 29.
Hereinafter, the excitation electrode group 23A will be described in detail. The excitation electrode group 22A is the same as the excitation electrode group 22, and a description thereof will be omitted.

As shown in FIG. 7, the excitation electrode 234A is formed with a plurality of fine holes 2341 penetrating in the thickness direction. Although not shown, the excitation electrode 233A is similarly formed with a plurality of fine holes penetrating in the thickness direction.
As shown in FIG. 6, as in the first embodiment described above, the excitation electrode 231 is formed with a plurality of fine holes 2311 penetrating in the thickness direction. Although not shown, the excitation electrode 232 is also formed with a plurality of fine holes penetrating in the thickness direction.

The vibration characteristics of the vibrating arm 29 are adjusted by forming such a plurality of holes in the excitation electrodes 231, 232, 233 A, and 234 A, respectively.
In the present embodiment, a plurality of holes as described above are formed on both excitation electrodes (excitation electrode 231 and excitation electrodes 233A and 234A, and excitation electrode 232 and excitation electrodes 233A and 234A) having different polarities. Therefore, the number and area of the plurality of holes per one excitation electrode can be reduced as compared with the case where a plurality of holes are formed only in one of the excitation electrodes to be paired. Therefore, the vibration characteristics of the vibrating arm 29 can be adjusted while preventing conduction failures such as disconnection of the excitation electrodes 231, 232, 233A, and 234A. In order to make such an effect remarkable, the hole of one excitation electrode (excitation electrodes 231 and 232) and the hole of the other excitation electrode (excitation electrodes 233A and 234A) should be as small as possible in the Y-axis direction. It is preferable not to overlap.
According to the second embodiment as described above, the same effects as those of the first embodiment described above can be obtained.

<Third Embodiment>
Next, a third embodiment of the vibration device of the invention will be described.
FIG. 8 is a top view showing a vibrating body provided in a vibrating device according to the third embodiment of the present invention, and FIG. 9 is a side view of the vibrating body shown in FIG.
Hereinafter, the vibration device according to the third embodiment will be described focusing on differences from the above-described embodiment, and description of similar matters will be omitted.

  In the vibrating device according to the third embodiment, the formation of the plurality of holes of the excitation electrodes provided on the upper surface and the lower surface of each vibration arm is omitted, and the excitation electrodes provided on each side surface of each vibration arm are fine. Except for forming a plurality of holes, it is substantially the same as the first embodiment. That is, the vibration device of the third embodiment is substantially the same as the second embodiment except that the formation of the plurality of holes of the excitation electrodes provided on the upper surface and the lower surface of each vibration arm is omitted. In FIGS. 8 and 9, the same components as those in the above-described embodiment are denoted by the same reference numerals.

As shown in FIG. 8, the vibrating body 2 </ b> B of the vibrating device according to the present embodiment includes excitation electrode groups 22 </ b> B and 23 </ b> B provided on the vibrating substrate 21.
The excitation electrode group 22 </ b> B is provided on the vibrating arm 28, and the excitation electrode group 23 </ b> B is provided on the vibrating arm 29.
Such an excitation electrode group 22B includes the excitation electrode 221B provided on the upper surface of the vibrating arm 28, the excitation electrode 222B provided on the lower surface of the vibrating arm 28, and one side surface of the vibrating arm 28. The excitation electrode 223 </ b> A provided and the excitation electrode 224 </ b> A provided on the other side surface of the vibrating arm 28 are configured.

The excitation electrode group 23 </ b> B is provided on one side surface of the vibration arm 29, the excitation electrode 231 </ b> B provided on the upper surface of the vibration arm 29, the excitation electrode 232 </ b> B provided on the lower surface of the vibration arm 29. And the excitation electrode 234A provided on the other side surface of the vibrating arm 29.
Hereinafter, the excitation electrode group 23B will be described in detail. Since the excitation electrode group 22B is the same as the excitation electrode group 22B, the description thereof is omitted.

As shown in FIG. 9, a plurality of fine holes 2341 penetrating in the thickness direction are formed in the excitation electrode 234A, as in the second embodiment described above. Although not shown, the excitation electrode 233A is similarly formed with a plurality of fine holes penetrating in the thickness direction.
Further, as shown in FIG. 8, the excitation electrodes 221 and 222 are not formed with a plurality of holes such as the plurality of holes 2341 described above. That is, the excitation electrodes 221 and 222 are configured as dense layers without being patterned on the inside of the contour.

The vibration characteristics of the vibrating arm 29 are adjusted by forming such a plurality of holes in the excitation electrodes 233A and 234A, respectively.
In the present embodiment, the hole existence ratio of the excitation electrodes 233A and 234A is preferably the same as the hole existence ratio of the excitation electrodes 221 and 222 of the first embodiment described above.
According to the third embodiment as described above, the same effects as those of the first embodiment described above can be obtained.

<Fourth embodiment>
Next, a fourth embodiment of the vibration device of the invention will be described.
10 is a bottom view showing a vibrating body provided in a vibrating device according to a fourth embodiment of the present invention, FIG. 11 is a cross-sectional view taken along line AA in FIG. 10, and FIG. 12 is a vibrating body in FIG. FIG. 13 is a diagram omitting illustration of each second electrode layer provided in FIG. 10, FIG. 13 is a diagram omitting illustration of each second electrode layer and each piezoelectric layer provided in the vibrating body in FIG. FIG. 11 is a perspective view for explaining the operation of the vibrating body shown in FIG. 10.

Hereinafter, the vibration device according to 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 vibrating device of the fourth embodiment has a different number of vibrating arms, and in the configuration in which each vibrating arm is vibrated by a piezoelectric element, a plurality of fine electrodes are respectively formed on the first electrode layer and the second electrode layer of the piezoelectric element. Except for the formation of this hole, it is substantially the same as the first embodiment.

The vibrating body 2C of the vibrating device of the present embodiment is a tripod tuning fork type vibrating body as shown in FIG. The vibrating body 2C includes a vibrating substrate 21C and piezoelectric elements 22C, 23C, and 24C provided on the vibrating substrate 21C.
The vibration substrate 21C includes a base portion 27C and three vibration arms 28C, 29C, and 30C.

  The constituent material of the vibration substrate 21C is not particularly limited as long as desired vibration characteristics can be exhibited, and various piezoelectric materials and various non-piezoelectric materials can be used. Examples of the piezoelectric material include crystal, lithium tantalate, lithium niobate, lithium borate, and barium titanate. In particular, quartz is preferable as the piezoelectric material constituting the vibration substrate 21C. When the vibration substrate 21C is made of quartz, the vibration characteristics of the vibration substrate 21C can be made excellent. In addition, the vibration substrate 21C can be formed with high dimensional accuracy by etching.

Examples of the non-piezoelectric material include silicon and quartz. In particular, silicon is preferable as the non-piezoelectric material constituting the vibration substrate 21C. When the vibration substrate 21C is made of silicon, the vibration characteristics of the vibration substrate 21C can be made excellent. In addition, the vibration substrate 21C can be formed with high dimensional accuracy by etching.
In such a vibration substrate 21 </ b> C, the base portion 27 </ b> C has a square shape including a pair of sides parallel to the X-axis direction and a pair of sides parallel to the Y-axis direction in plan view. . The shape of the base portion 27C in plan view is not limited to this.

Then, three vibrating arms 28C, 29C, and 30C are connected to one side parallel to the X-axis direction of the base portion 27C.
The vibrating arms 28C and 29C are connected to both ends of the base portion 27C in the X-axis direction, and the vibrating arms 30C are connected to the central portion of the base portion 27 in the X-axis direction.
The three vibrating arms 28C, 29C, and 30C extend from the base portion 27C in the Y-axis direction and are arranged side by side in the X-axis direction.

Each of the vibrating arms 28C, 29C, and 30C has a longitudinal shape, and an end portion (base end portion) on the base portion 27C side is a fixed end, and an end portion (tip end portion) opposite to the base portion 27C is a free end. Become.
The vibrating arms 28C and 29C are formed so as to have the same width, and the vibrating arm 30C is formed so as to be twice as wide as the vibrating arms 28C and 29C. As a result, the vibration arms 28C and 29C are bent and vibrated in the Z-axis direction, and vibration leakage is reduced when the vibration arm 30C is bent and vibrated in the Z-axis direction in the opposite direction (in reverse phase) to the vibration arms 28C and 29C. can do.

  In addition, each of the vibrating arms 28C, 29C, and 30C has a constant width over the entire region in the longitudinal direction. It should be noted that a mass part (hammer head) having a larger cross-sectional area than the base end part may be provided at each distal end part of the vibrating arms 28C, 29C, 30C as necessary. In this case, the vibrating body 2C can be made smaller, and the bending vibration frequency of the vibrating arms 28C, 29C, 30C can be further reduced.

As shown in FIG. 11, a piezoelectric element 22C is provided on such a vibrating arm 28C, a piezoelectric element 23C is provided on the vibrating arm 29C, and further, on the vibrating arm 30C. A piezoelectric element 24C is provided.
The piezoelectric element 22C has a function of expanding and contracting by energization to bend and vibrate the vibrating arm 28C in the Z-axis direction. In addition, the piezoelectric element 23C has a function of expanding and contracting by energization to bend and vibrate the vibrating arm 29C in the Z-axis direction. In addition, the piezoelectric element 24C has a function of expanding and contracting by energization to bend and vibrate the vibrating arm 30C in the Z-axis direction.
In such a piezoelectric element 22C, as shown in FIG. 11, a first electrode layer 221C, a piezoelectric layer (piezoelectric thin film) 222C, and a second electrode layer 223C are laminated in this order on a vibrating arm 28C. Configured.

As shown in FIG. 10, in the second electrode layer 223C, a plurality of fine holes 2231C penetrating in the thickness direction are formed in a slit shape. As shown in FIG. 13, the first electrode layer 221C is formed with a plurality of fine holes 2211C penetrating in the thickness direction in a slit shape. The vibration characteristics of the vibrating arm 28C are adjusted by forming such a plurality of holes in the first electrode layer 221C and the second electrode layer 223C, respectively. The adjustment of the vibration characteristics of the vibrating arm 28C will be described later in detail.
In such a piezoelectric element 22C, since the piezoelectric layer 222C is disposed between the first electrode layer 221C and the second electrode layer 223C, the first electrode layer 221C and the second electrode When a voltage is applied between the layer 223C and the piezoelectric layer 222C, an electric field in the Z-axis direction is generated. Due to this electric field, the piezoelectric layer 222C expands or contracts in the Y-axis direction, causing the vibrating arm 28C to bend and vibrate in the Z-axis direction.

Similarly, the piezoelectric element 23C is configured by laminating a first electrode layer 231C, a piezoelectric layer (piezoelectric thin film) 232C, and a second electrode layer 233C in this order on the vibrating arm 29C. The piezoelectric element 24C is configured by laminating a first electrode layer 241C, a piezoelectric layer (piezoelectric thin film) 242C, and a second electrode layer 243C in this order on the vibrating arm 30C.
As shown in FIG. 10, a plurality of fine holes 2331C penetrating in the thickness direction are formed in the second electrode layer 233C. Further, as shown in FIG. 13, the first electrode layer 231C has a plurality of fine holes 2311C penetrating in the thickness direction. By forming such a plurality of holes in the first electrode layer 231C and the second electrode layer 233C, the vibration characteristics of the vibrating arm 29C are adjusted.

  Further, as shown in FIG. 10, the second electrode layer 243C has a plurality of fine holes 2431C penetrating in the thickness direction. As shown in FIG. 13, the first electrode layer 241C has a plurality of fine holes 2411C penetrating in the thickness direction. The vibration characteristics of the vibrating arm 30C are adjusted by forming such a plurality of holes in the first electrode layer 241C and the second electrode layer 243C, respectively.

  In such a piezoelectric element 23C, when a voltage is applied between the first electrode layer 231C and the second electrode layer 233C, the piezoelectric layer 232C expands or contracts in the Y-axis direction and vibrates. The arm 29C is bent and vibrated in the Z-axis direction. When a voltage is applied between the first electrode layer 241C and the second electrode layer 243C, the piezoelectric layer 242C expands or contracts in the Y-axis direction, and the vibrating arm 30C is bent in the Z-axis direction. Vibrate.

  Also, as shown in FIGS. 10, 12, and 13, the first electrode layers 221C, 231C and the second electrode layer 243C described above are electrically connected to the connection electrode 41C provided on the lower surface of the base portion 27C. Yes. The first electrode layer 241C and the second electrode layers 223C and 233C are electrically connected to a connection electrode 42C provided on the lower surface of the base portion 27C. Here, the first electrode layer 241C is electrically connected to the connection electrode 41C via the conductor portion (conductor post) 251 shown in FIG. Further, the first electrode layers 221C and 231C are electrically connected to the connection electrode 42C through the conductor portion (conductor post) 252 shown in FIG.

Such first electrode layers 221C, 231C, 241C, second electrode layers 223C, 233C, 243C, connection electrodes 41C, 42C and conductor portions 251, 252 are respectively aluminum, aluminum alloy, silver, silver alloy, It can be formed of a metal material having excellent conductivity, such as chromium, a chromium alloy, gold, or a gold-chrome laminated film.
Examples of methods for forming these electrodes include physical film formation methods such as sputtering and vacuum deposition, chemical vapor deposition methods such as CVD, and various coating methods such as an ink jet method. In forming these electrodes and the like, it is preferable to use a photolithography method.

Examples of the constituent material (piezoelectric material) of the piezoelectric layers 222C, 232C, and 242C include crystal, lithium tantalate, lithium niobate, lithium borate, and barium titanate, respectively.
Examples of the method for forming these piezoelectric layers include physical film formation methods such as sputtering and vacuum vapor deposition, chemical vapor deposition methods such as CVD, and various coating methods such as an ink jet method.

  In the vibrating body 2C having such a configuration, when a voltage is applied between the connection electrode 41C and the connection electrode 42C, the first electrode layers 221C and 231C, the second electrode layer 243C, and the first electrode A voltage in the Z-axis direction is applied to each of the piezoelectric layers 222C, 232C, and 242C described above so that the layer 241C and the second electrode layers 223C and 233C have opposite polarities. Accordingly, the vibrating arms 28C, 29C, and 30C can be flexibly vibrated at a certain frequency (resonance frequency) by the inverse piezoelectric effect of the piezoelectric material.

At this time, as shown in FIG. 14, the vibrating arms 28C and 29C bend and vibrate in the same direction, and the vibrating arm 30C bends and vibrates in the direction opposite to the vibrating arms 28C and 29C. Accordingly, the three vibrating arms 28C, 29C, and 30C can be flexibly vibrated in the Z-axis direction while preventing vibration leakage.
Further, when the vibrating arms 28C, 29C, 30C are flexibly vibrated, a voltage is generated between the connection electrodes 41C, 42C at a certain frequency due to the piezoelectric effect of the piezoelectric material. Using these properties, the vibrator 2C can generate an electrical signal that vibrates at a resonance frequency.

  In the present embodiment, the piezoelectric material of the piezoelectric layers 222C, 232C, and 242C has been described as an example in which the polarization direction or the crystal axis direction is the same direction. However, the present invention is not limited to this. The polarization direction or crystal axis direction of the body layer 242C is opposite to that of the piezoelectric layers 222C and 232C, and the first electrode layers 221C, 231C, and 241C (second electrode layers 223C, 233C, and 243C) have the same polarity A voltage may be applied so that

Here, the adjustment of the vibration characteristics of the vibrating arm 28C will be described in detail. The adjustment of the vibration characteristics of the vibration arms 29C and 30C is the same as the adjustment of the vibration characteristics of the vibration arm 28C, and thus the description thereof is omitted.
As described above, in the piezoelectric element 22C, the first electrode layer 221C has a plurality of fine holes 2211C penetrating in the thickness direction, and the second electrode layer 223C in the thickness direction. A plurality of fine holes 2231C penetrating therethrough are formed.

In particular, the first electrode layer 221C is partially formed with a plurality of fine holes 2211C penetrating in the thickness direction. The second electrode layer 223C is partially formed with a plurality of fine holes 2231C penetrating in the thickness direction.
As a result, even if the length L2 of the piezoelectric element 22C in the Y-axis direction on the vibrating arm 28C is increased, the electric field (piezoelectric layer) generated between the first electrode layer 221C and the second electrode layer 223C. The vibration characteristic of the vibrating arm 28C can be adjusted by reducing the density of the electric field contributing to the unnecessary vibration mode among the electric field applied to 222C.

For this reason, the vibrating body 2C can reduce unnecessary vibration modes and can be driven efficiently.
Therefore, the plurality of holes 2211C and 2231C are unevenly distributed (partially formed) in the middle of the first electrode layer 221C or the second electrode layer 223C in the extending direction of the vibrating arm 28C.

Thereby, like the vibrating arm 28 of the above-described embodiment, the vibration characteristic of the vibrating arm 28 </ b> C is adjusted by changing the ratio between the CI value of the harmonic (higher order vibration mode) and the CI value of the fundamental wave. Can do.
Further, the plurality of holes 2211C and 2231C are unevenly distributed in portions corresponding to the central portion of the first electrode layer 221C or the second electrode layer 223C in the extending direction (Y-axis direction) of the vibrating arm 28C. (Partially formed)

  Accordingly, even if the length L2 of the piezoelectric element 22C in the Y-axis direction is increased, the excitation of the higher-order vibration mode of the vibrating arm 28C is significantly suppressed, and the CI value of the higher-order vibration mode of the vibrating body 2C is reduced. Can be increased. That is, similar to the vibrating arm 28 of the above-described embodiment, the CI value of the fundamental wave is reduced and the CI value of the harmonic is increased to increase the CI value ratio (harmonic CI value / fundamental CI value). it can.

  Further, when the length of the vibrating arm 28C in the extending direction (Y-axis direction) is L1, and the length of the piezoelectric element 22C in the same direction on the vibrating arm 28C is L2, 0.5 <L2 / The relationship of L1 <1 is satisfied. Thereby, like the vibrating arm 28 of the above-described embodiment, the CI value of the fundamental wave can be reduced and the excitation of the vibrating arm 28C can be made efficient. Further, similarly to the vibrating arm 28 of the above-described embodiment, from this viewpoint, it is particularly preferable that the lengths L1 and L2 satisfy the relationship of 0.6 <L2 / L1 <0.9. It is more preferable to satisfy the relationship of 7 <L2 / L1 <0.8.

  In addition, the ratio of the area occupied by the holes 2211C per unit area of the first electrode layer 221C (hole existence ratio) and the ratio of the area occupied by the holes 2231C per unit area of the second electrode layer 223C (hole existence ratio). ) Are gradually decreased from the central portion in the extending direction (Y-axis direction) of the vibrating arm 28C toward the distal end side and the proximal end side, respectively. As a result, similarly to the vibrating arm 28 of the above-described embodiment, the excitation value of the vibrating arm 28C is made smooth and efficient, while the harmonic CI value is increased, and the CI value ratio (harmonic CI value / fundamental wave CI) is increased. Value).

  In the present embodiment, since the plurality of holes as described above are formed in both the first electrode layer 221C and the second electrode layer 223C, the first electrode layer 221C or the second electrode layer 223C is formed. Compared with the case where a plurality of holes are formed only in any one of the electrode layers, the number and area of the plurality of holes per electrode layer can be reduced. Therefore, the vibration characteristics of the vibrating arm 28C can be adjusted while preventing the mechanical strength of the first electrode layer 221C and the second electrode layer 223C from decreasing. In order to make such an effect remarkable, it is preferable that the hole 2211C and the hole 2231C are not overlapped as much as possible in a plan view.

  In addition, since the first electrode layer 221C and the second electrode layer 223C are relatively thin, the plurality of holes 2211C and 2231C can be formed relatively easily and with high accuracy. Even if a plurality of holes 2211C are provided in the first electrode layer 221C, the level difference caused by the presence or absence of the holes 2211C in the first electrode layer 221C is extremely small and does not adversely affect the formation of the piezoelectric layer 222C. In addition, since the second electrode layer 223C is formed after the first electrode layer 221C and the piezoelectric layer 222C, the first electrode layer 221C can be formed even if a plurality of holes 2231C are provided in the second electrode layer 223C. Further, the formation of the piezoelectric layer 222C is not adversely affected.

  In the present embodiment, a plurality of holes such as the plurality of holes 2211C and 2231C are not formed in the piezoelectric layer 222C. That is, the piezoelectric layer 222C is configured as a dense layer without being patterned on the inside of the contour. Thereby, the surface of the piezoelectric layer 222C can be flattened, and as a result, the second electrode layer 223C can be formed uniformly. Further, the distance can be made uniform between the first electrode layer 221C and the second electrode layer 223C.

Note that even if a plurality of holes such as the plurality of holes 2211C and 2231C are formed in the piezoelectric layer 222C, the vibration characteristics of the vibrating arm 28C can be adjusted.
Moreover, each hole 2211C and 2231C has comprised the slit shape by planar view. The holes 2211C and 2231C having such a planar view shape can be easily formed with highly accurate dimensions and positions, and adverse effects on the piezoelectric element 22C can be reduced. In particular, the vibration characteristics of the vibrating arm 28C can be adjusted by changing the width, interval (pitch), length, and the like of the holes 2211C and 2231C. Therefore, the vibrating arm 28C can be adjusted relatively easily to a desired vibration characteristic.

  The slit-shaped holes 2211C and 2231C extend in the width direction (X-axis direction) orthogonal to the extending direction (Y-axis direction) of the vibrating arm 28C. Therefore, the formation of the plurality of holes 2211C and 2231C can be prevented from adversely affecting the vibration characteristics of the vibrating arm 28C. Thereby, the vibrating arm 28C can be adjusted relatively easily to a desired vibration characteristic. The slit-shaped holes 2211C and 2231C may be formed so as to extend in the Y-axis direction.

In the present embodiment, the plurality of holes 2211C and 2231C are formed to have the same length and width. Therefore, the hole existence ratio as described above is realized by changing the interval between the holes 2211C and the interval between the holes 2231C in accordance with the position in the Y-axis direction.
Note that the plurality of holes 2211C and 2231C may be formed to have different lengths and widths. In this case, even if the distance between the holes 2211C and the distance between the holes 2231C are constant, the length and width of the holes 2211C and 2231C are changed in accordance with the position in the Y-axis direction, so A proportion can be realized.

The widths of the slit-shaped holes 2211C and 2231C are each preferably 0.01 to 100 μm, and more preferably 0.1 to 10 μm. This makes it possible to adjust the vibrating arm 28C to a desired vibration characteristic while making the formation of the plurality of holes 2211C and 2231C comparatively easy.
According to the fourth embodiment as described above, the same effects as those of the first embodiment described above can be obtained.

〔Electronics〕
The vibration device 1 having any one of the vibrators 2, 2 </ b> A, 2 </ b> B, and 2 </ b> C according to each embodiment described above can be applied to various electronic devices, and these electronic devices have high reliability. . 15 and 16 show a mobile phone as an example of the electronic apparatus of the present invention. FIG. 15 is a perspective view showing an outline of the appearance of the mobile phone, and FIG. 16 is a circuit block diagram for explaining the circuit configuration of the mobile phone. This mobile phone 400 will be described using an example using the vibrating device 1 (FIG. 1) having the vibrating body 2, and the configuration and operation of the vibrating body 2 will be omitted by using the same reference numerals.
As shown in FIG. 15, a mobile phone 400 is provided with an LCD (Liquid Crystal Display) 401 as a display unit, a key 402 as an input unit for numbers, a microphone 403, a speaker 411, and the like. As shown in FIG. 16, when transmitting by mobile phone 400, when the user inputs his / her voice to microphone 403, the signal is pulse width modulation / coding block 404 and modulator / demodulator block. 405, and further transmitted from the antenna 408 via the transmitter 406 and the antenna switch 407.

On the other hand, a signal transmitted from another person's telephone is received by the antenna 408, and is input to the modulator / demodulator block 405 from the receiver 410 through the antenna switch 407 and the reception filter 409. The modulated or demodulated signal passes through the pulse width modulation / coding block 404 and is output to the speaker 411 as a voice. A controller 412 is provided to control the antenna switch 407, the modulator / demodulator block 405, and the like.
In addition to the above, the controller 412 controls the LCD 401, which is a display unit, the key 402, which is an input unit for numbers, and further the RAM 413, the ROM 414, and the like. In addition, there is a demand for downsizing the mobile phone 400, and the vibrator 2 described above is used to meet such a demand. Note that the mobile phone 400 includes a temperature-compensated crystal oscillator 415, a receiver synthesizer 416, a transmitter synthesizer 417, and the like as other constituent blocks, but the description thereof is omitted here.

  Moreover, as an electronic apparatus provided with the vibration device 1 of this invention, the personal computer (mobile personal computer) 500 shown in FIG. 17 is also mentioned. The personal computer 500 includes a display unit 501, an input key unit 502, and the like, and the above-described vibration device 1 is used as a reference clock for electrical control.

  When the vibrating body 2 is used in the vibrating device 1 used in the mobile phone 400 or the personal computer 500, the first direction (vibration) of the excitation electrode groups 22 and 23 on the vibrating arms 28 and 29 is used. While increasing the length in the arm extending direction), the density of the electric field that contributes to unnecessary vibration modes out of the electric field generated between the pair of excitation electrodes (the electric field applied to the vibrating arm) is reduced, The vibration characteristics of the vibrating arms 28 and 29 can be improved. Thereby, the vibration device 1 can reduce unnecessary vibration modes and can be driven efficiently, and the mobile phone 400 and the personal computer 500 including the vibration device 1 can achieve high reliability. Note that the cellular phone 400 and the personal computer 500 can achieve the same effects even when the vibrating bodies 2A, 2B, and 2C are used in the vibrating device 1.

The vibrating device 1 of each embodiment as described above can be applied to various electronic devices other than the mobile phone 400 and the personal computer 500, and the obtained electronic device has high reliability.
These electronic devices include, for example, personal computers (mobile personal computers), mobile phones, digital still cameras, ink jet ejection devices (for example, ink jet printers), laptop personal computers, televisions, video cameras, video tape recorders, cars Navigation devices, pagers, electronic notebooks (including communication functions), electronic dictionaries, calculators, electronic game devices, word processors, workstations, video phones, crime prevention TV monitors, electronic binoculars, POS terminals, medical devices (for example, electronic thermometers, Blood pressure monitor, blood glucose meter, electrocardiogram measuring device, ultrasonic diagnostic device, electronic endoscope), fish detector, various measuring instruments, instruments (eg, vehicle, aircraft, ship instruments), flight simulator, etc. .

  As described above, the vibration device 1 and the electronic apparatus 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 may be any configuration having the same function. Can be substituted. In addition, any other component may be added to the present invention. Further, the present invention may be a combination of any two or more configurations (features) of the above embodiments.

For example, in the above-described embodiment, the case where the vibrating bodies 2, 2 </ b> A, 2 </ b> B, and 2 </ b> C have two or three vibrating arms has been described as an example, but the number of vibrating arms is one or four or more. Also good.
In the fourth embodiment described above, a plurality of fine holes are formed in both the first electrode layers 221C, 231C, 241C and the second electrode layers 223C, 233C, 243C of the piezoelectric elements 22C, 23C, 24C. However, even if a plurality of fine holes are formed only in any one of the first electrode layers 221C, 231C, and 241C or the second electrode layers 223C, 233C, and 243C, vibration is generated. The vibration characteristics of the arms 28C, 29C, and 30C can be adjusted.
In addition, the vibration device 1 of the present invention includes a piezoelectric oscillator such as a crystal oscillator (SPXO), a voltage controlled crystal oscillator (VCXO), a temperature compensated crystal oscillator (TCXO), a crystal oscillator with a thermostat (OCXO), a gyro sensor, and the like. Applies to

  DESCRIPTION OF SYMBOLS 1 ... Vibration device 2 ... Vibration body 2A ... Vibration body 2B ... Vibration body 2C ... Vibration body 3 ... Package 21 ... Vibration board 21C ... Vibration board 22 ... Excitation electrode group 22A ... Excitation electrode Group 22B ... Excitation electrode group 22C ... Piezoelectric element 23 ... Excitation electrode group 23A ... Excitation electrode group 23B ... Excitation electrode group 23C ... Piezoelectric element 24C ... Piezoelectric element 27 ... Base 27C ... Base 28 ... Vibration arm 28C ... Vibration arm 29 ... Vibration arm 29C ... Vibration arm 30C ... Vibration arm 31 ... Base substrate 32 ... Frame member 33 ... Lid member 34a ... External terminal 34b ... External Terminal 34c External terminal 34d External terminal 35a Mount electrode 35b Mount electrode 36a Conductive adhesive 36b Conductive adhesive 37 Internal empty 41 ... Connection electrode 41C ... Connection electrode 42 ... Connection electrode 42C ... Connection electrode 50 ... Drive circuit section 221 ... Excitation electrode 221B ... Excitation electrode 221C ... First electrode layer 222 ... Excitation electrode 222B ... Excitation electrode 222C ... Piezoelectric layer 223 ... Excitation electrode 223A ... Excitation electrode 223C ... Second electrode layer 224 ... Excitation electrode 224A ... Excitation electrode 231 ... Excitation electrode 231B ... Excitation electrode 231C First electrode layer 232 Excitation electrode 232B Excitation electrode 232C Piezoelectric layer 233 Excitation electrode 233A Excitation electrode 233C Second electrode layer 234 Excitation electrode 234A Excitation Electrode 241C... First electrode layer 242C... Piezoelectric layer 243C... Second electrode layer 251. Body 2211 ... Hole 2211C ... Hole 2231C ... Hole 2311 ... Hole 2311C ... Hole 2331C ... Hole 2341 ... Hole 2411C ... Hole 2431C ... Hole.

Claims (14)

A vibration body, and a drive circuit unit that drives the vibration body,
The vibrator is
The base,
A plurality of resonating arms extending in the first direction from the base and arranged side by side in a second direction orthogonal to the first direction;
A pair of excitation electrodes provided on each of the vibrating arms and configured to excite the vibrating arms by energization;
A vibrating device, wherein a plurality of holes penetrating in the thickness direction are partially formed in at least one of the pair of excitation electrodes.   2. The vibrating device according to claim 1, wherein the plurality of holes are formed to be unevenly distributed in the first direction in the at least one excitation electrode.   The vibrating device according to claim 2, wherein the plurality of holes are unevenly distributed in a central portion of the excitation electrode in the first direction of the vibrating arm.   4. The vibrating device according to claim 3, wherein a ratio of an area occupied by the hole per unit area of the excitation electrode gradually decreases from the central portion in the first direction toward the tip side of the vibrating arm. .   The ratio of the area which the said hole occupies per unit area of the said excitation electrode is decreasing gradually toward the base end side from the center part in the said 1st direction of the said vibrating arm. Vibration device.   When the length of the vibrating arm in the first direction is L1, and the length of the excitation electrode on the vibrating arm in the first direction is L2, 0.5 <L2 / L1 <1. The vibration device according to claim 1, wherein the relationship is satisfied. A vibration body, and a drive circuit unit that drives the vibration body,
The vibrator is
The base,
A plurality of resonating arms extending in the first direction from the base and arranged side by side in a second direction orthogonal to the first direction;
A piezoelectric element that is provided on each vibrating arm and expands and contracts by energization to vibrate the vibrating arm;
The piezoelectric element includes a first electrode layer, a second electrode layer, and a piezoelectric layer located between the first electrode layer and the second electrode layer,
A plurality of holes penetrating in the thickness direction are partially formed in at least one of the first electrode layer, the piezoelectric layer, and the second electrode layer. And vibration device.   The number of the vibrating arms is three or more, and two adjacent vibrating arms are opposite to each other in a third direction orthogonal to the first direction and the second direction by expansion and contraction of the piezoelectric element. The vibrating device according to claim 7, which is bent and vibrated.   The vibrating device according to claim 1, wherein each of the holes has a circular shape in plan view.   The vibrating device according to claim 9, wherein an average diameter of the plurality of holes is 0.01 to 100 μm.   The vibrating device according to claim 1, wherein each of the holes has a slit shape in plan view.   The vibrating device according to claim 11, wherein each of the slit-like holes extends in the second direction.   The vibrating device according to claim 11 or 12, wherein a width of the slit-shaped hole is 0.01 to 100 µm.   An electronic apparatus comprising the vibrating device according to claim 1.

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