JP2012060264A - Vibration piece, vibrator, vibration device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration piece capable of exhibiting excellent vibration characteristics, and further to provide a vibrator, a vibration device and an electronic apparatus that are provided with the vibration piece and have excellent reliability.SOLUTION: A vibration piece 2 has; a base section 27; and a plurality of vibration arms 28, 29 and 30, which extends from the base section 27 in a Y axis direction and is disposed side by side in an X axis direction. Each of the plurality of vibration arms 28, 29 and 30 is bent and vibrated in a Z axis direction. In vibration arms 28 and 29, which are positioned at both ends of the X axis direction, of the plurality of vibration arms 28, 29 and 30, first sections thereof being adjacent to a vibration arm 30 side in the X axis direction have parts having higher rigidity than that of second sections thereof positioned opposite to the first sections.

Description

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

As a vibrating device such as a crystal oscillator, a vibrating device including a tuning fork type vibrating piece including a plurality of vibrating arms is known (for example, see Patent Document 1).
For example, the resonator element disclosed in Patent Document 1 includes a base, three vibrating arms extending from the base so as to be parallel to each other, and a lower electrode film, a piezoelectric film, and an upper electrode film on each vibrating arm. And a piezoelectric element formed and formed in this order. In such a resonator element, each piezoelectric element expands and contracts the piezoelectric layer when an electric field is applied between the lower electrode film and the upper electrode film, and the vibrating arm extends in the thickness direction of the base (so-called out-of-plane). Direction). In the following, for convenience of explanation, the vibrating arm located at the center of the three vibrating arms provided in parallel is referred to as a “central vibrating arm” and is located at both ends, that is, facing through the central vibrating arm. The two resonating arms arranged are referred to as “end resonating arms”.

However, in the resonator element described in Patent Document 1, the rigidity of the portion of each end vibrating arm on the central vibrating arm side is lower than the rigidity of the portion on the opposite side of the central vibrating arm. Such a stiffness difference is that there is another vibrating arm (center vibrating arm) on one side of each end vibrating arm, but there is no vibrating arm on the other side. This is presumably due to the asymmetrical structure.
Therefore, when bending each end vibration arm in the thickness direction of the base as described above, each end vibration arm is centered on the axis of each end vibration arm in addition to vibration in the thickness direction. Torsional deformation occurs. As a result, an unintentional vibration mode is generated in the vibrating piece, and each vibrating arm cannot be vibrated efficiently, resulting in a problem that the oscillation capacity and accuracy of the vibrating piece are lowered.

JP 2009-5022 A

  An object of the present invention is to provide a resonator element that can exhibit excellent vibration characteristics, and to provide a highly reliable vibrator, resonator device, and electronic apparatus including the resonator element.

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 resonator element according to the invention includes a base provided on a plane including a first direction and a second direction orthogonal to the first direction;
A plurality of vibrating arms extending in the first direction from the base and provided side by side in the second direction;
Each of the vibrating arms bends and vibrates in the normal direction of the plane,
The plurality of resonating arms include a pair of outer resonating arms located at both ends in the second direction,
Each of the outer vibrating arms includes a first portion located on the other outer vibrating arm side by a line that bisects the width of the outer vibrating arm in the second direction, and the other outer vibrating arm. When divided into the second part located on the opposite side, the first part has a portion having higher rigidity than the second part.
Accordingly, it is possible to prevent or suppress the torsional deformation of each outer vibrating arm during bending vibration, and to efficiently bend and vibrate each vibrating arm. Therefore, a vibrating piece having excellent vibration characteristics can be obtained. Obtainable.

[Application Example 2]
In the resonator element according to the aspect of the invention, it is preferable that the first part of each of the outer vibrating arms has a thicker part than the second part.
Thereby, it is possible to prevent or suppress the torsional deformation of each outer vibrating arm during bending vibration with a simple configuration.

[Application Example 3]
In the resonator element according to the aspect of the invention, each of the outer vibrating arms includes a first surface that is compressed or extended by the bending vibration, and an extension when the first surface is compressed and the first surface is extended. A second surface that compresses the first surface, and a third surface that connects the first surface and the second surface;
It is preferable that a reinforcing member is provided in the first portion of at least one of the first surface, the second surface, and the third surface.
Thereby, installation of a reinforcement member can be performed easily.

[Application Example 4]
In the resonator element according to the aspect of the invention, it is preferable that the reinforcing member is provided at a distal end portion of each of the outer vibrating arms.
Thereby, the installation space of the piezoelectric element for bending and vibrating each outer vibrating arm can be sufficiently secured.

[Application Example 5]
In the resonator element according to the aspect of the invention, the reinforcing member is configured using any one of SiO ₂ , Al, Al ₂ O ₃ , TiO ₂ , Cr, Fe, Ni, Cu, Ag, Au, Ti, and Pt. It is preferable to be characterized by this.
A metal or an insulating material (for example, ceramics) can be easily and accurately formed by a vapor deposition method. For this reason, the reinforcing member can be easily formed by forming the reinforcing member by depositing a metal or an insulating material.

[Application Example 6]
The vibrator of the present invention includes the resonator element of the present invention,
And a package containing the resonator element.
Thereby, a vibrator having excellent reliability can be provided.
[Application Example 7]
The vibrating device of the present invention includes the vibrating piece of the present invention,
And an oscillation circuit connected to the resonator 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 resonator 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.

1 is a cross-sectional view showing a vibrator according to a first embodiment of the present invention. FIG. 2 is a top view showing the vibrator shown in FIG. 1. FIG. 2 is a bottom view showing a resonator element provided in the vibrator shown in FIG. 1. (A) is the sectional view on the AA line in FIG. 2, (b) is the sectional view on the BB line in FIG. FIG. 3 is a perspective view for explaining the operation of the resonator element shown in FIG. 2. It is a top view for demonstrating operation | movement of the conventional vibration piece. It is a partial expanded sectional view for demonstrating the reinforcement member which concerns on 2nd Embodiment of this invention. It is sectional drawing for demonstrating the reinforcement member which concerns on 3rd Embodiment of this invention. It is sectional drawing for demonstrating the reinforcement member which concerns on 4th Embodiment of this invention. It is sectional drawing for demonstrating the reinforcement member which concerns on 5th Embodiment of this invention. FIG. 10 is a top view illustrating a vibrator according to a sixth embodiment of the invention. It is CC sectional view taken on the line in FIG. It is a partial expansion perspective view of a vibrator concerning a 7th embodiment of the present invention. It is a partial expansion perspective view of a vibrator concerning an 8th embodiment of the present invention. It is a partial expansion perspective view of a vibrator concerning a 9th embodiment of the present invention. It is a partial expansion perspective view of a vibrator concerning a 10th embodiment of the present invention. It is sectional drawing for demonstrating the vibrator | oscillator concerning 11th Embodiment of this invention. It is a figure which shows an electronic device (notebook-type personal computer) provided with the vibration piece of this invention. It is a figure which shows an electronic device (cellular phone) provided with the vibration piece of this invention. It is a figure which shows an electronic device (digital still camera) provided with the vibration piece of this invention.

Hereinafter, a resonator element, a vibrator, a vibration 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 the vibrator according to the first embodiment of the present invention, FIG. 2 is a top view showing the vibrator shown in FIG. 1, and FIG. 3 is a vibration provided in the vibrator shown in FIG. FIG. 4A is a cross-sectional view taken along line AA in FIG. 2, FIG. 4B is a cross-sectional view taken along line BB in FIG. 2, and FIG. 5 is FIG. FIG. 6 is a perspective view for explaining the operation of the resonator element, and FIG. 6 is a plan view for explaining the operation of the conventional resonator element. In each figure, for convenience of explanation, an X axis, a Y axis, and a Z axis are illustrated as three axes orthogonal to each other. In the following, the direction parallel to the Y-axis (first direction) is the Y-axis direction, the direction parallel to the X-axis (second direction) is the “X-axis direction”, and the direction parallel to the Z-axis (first The normal direction of the plane including the second direction and the second direction) is referred to as the 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 vibrator 1 shown in FIG. 1 includes a vibrating piece 2 and a package 3 that houses the vibrating piece 2.
Hereinafter, each part which comprises the vibrator | oscillator 1 is demonstrated in detail sequentially.

(Vibration piece)
First, the resonator element 2 will be described.
The resonator element 2 is a three-leg tuning fork type resonator element as shown in FIG. The resonator element 2 includes a vibration substrate 21, piezoelectric elements 22, 23, 24 and connection electrodes 41, 42 provided on the vibration substrate 21, and reinforcing members 51, 52, 53.

The vibration substrate 21 has a base portion 27 and three vibration arms 28, 29, and 30.
The constituent material of the vibration substrate 21 is not particularly limited as long as it can exhibit desired vibration characteristics, 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, the piezoelectric material constituting the vibration substrate 21 is preferably quartz (X-cut plate, AT-cut plate, Z-cut plate, etc.). When the vibration substrate 21 is made of quartz, the vibration characteristics (particularly the frequency temperature characteristic) of the vibration substrate 21 can be made excellent. Further, the vibration substrate 21 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 21. When the vibration substrate 21 is made of silicon, a vibration substrate 21 having excellent vibration characteristics can be realized at a relatively low cost. In addition, it is easy to integrate the resonator element 2 and other circuit elements by forming an integrated circuit on the base 27. 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 substantially plate shape with the Z-axis direction as the thickness direction. As shown in FIGS. 1 and 3, the base portion 27 includes a thin portion 271 formed to be thin and a thick portion 272 formed to be thicker than the thin portion 271. They are arranged side by side in the axial direction.
The thin portion 271 is formed to have a thickness equal to each of the vibrating arms 28, 29, and 30 described later. Therefore, the thick portion 272 is a portion whose thickness in the Z-axis direction is larger than the thickness of each vibrating arm 28, 29, 30 in the Z-axis direction.
By forming the thin portion 271 and the thick portion 272 as described above, the thickness of the vibrating arms 28, 29, 30 is reduced to improve the vibration characteristics of the vibrating arms 28, 29, 30, and the vibrating piece 2 The handling property at the time of manufacturing can be made excellent.
Three vibrating arms 28, 29, and 30 are connected to the opposite side of the thin portion 271 of the base portion 27 to the thick portion 272.

The vibrating arms (outer vibrating arms) 28 and 29 are connected to both ends of the base 27 in the X-axis direction, and the vibrating arm 30 is connected to the center of the base 27 in the X-axis direction.
The three vibrating arms 28, 29, and 30 are provided so as to extend from the base portion 27 in the Y-axis direction so as to be parallel to each other. More specifically, the three vibrating arms 28, 29, and 30 extend from the base portion 27 in the Y axis direction and are provided side by side in the X axis direction.

Each of the vibrating arms 28, 29, and 30 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. .
In addition, each of the vibrating arms 28, 29, and 30 has a constant width over the entire area in the longitudinal direction. In addition, each vibrating arm 28, 29, 30 may have portions with different widths.
The vibrating arms 28, 29, and 30 are formed to have the same length. The lengths of the vibrating arms 28, 29, and 30 are set according to the width and thickness of the vibrating arms 28, 29, and 30, and may be different from each other.
In addition, you may provide the mass part (hammer head) with a larger cross-sectional area than a base end part in each front-end | tip part of the vibrating arms 28, 29, and 30 as needed. In this case, the vibrating piece 2 can be made smaller, and the bending vibration frequency of the vibrating arms 28, 29, and 30 can be further reduced.

  As shown in FIG. 4A, a reinforcing member 51 is provided on the upper surface 281 of the vibrating arm 28. Similarly, a reinforcing member 52 is provided on the upper surface 291 of the vibrating arm 29, and a reinforcing member 53 is provided on the upper surface 301 of the vibrating arm 30. Among the reinforcing members 51, 52, 53, the reinforcing members 51, 52 have a function of partially increasing the rigidity of the vibrating arms 28, 29, as will be described later. Further, the reinforcing members 51, 52, and 53 are, for example, as weight portions that adjust the resonance frequency of the vibrating arms 28, 29, and 30 by reducing the mass by removing part or all of them by irradiation with energy rays. Also works.

  As shown in FIG. 4B, the piezoelectric element 22 is provided on the vibrating arm 28, the piezoelectric element 23 is provided on the vibrating arm 29, and further on the vibrating arm 30. Is provided with a piezoelectric element 24. Thereby, even if the vibrating arms 28, 29, 30 themselves do not have piezoelectricity, or the vibrating arms 28, 29, 30 have piezoelectricity, the direction of the polarization axis or crystal axis thereof is the Z-axis direction. Even if it is not suitable for flexural vibration in the above, each vibrating arm 28, 29, 30 can be flexibly vibrated in the Z-axis direction relatively easily and efficiently. In addition, since the vibrating arms 28, 29, and 30 have piezoelectricity and the directions of the polarization axis and the crystal axis are not limited, the selection range of the materials of the vibrating arms 28, 29, and 30 is widened. Therefore, the resonator element 2 having desired vibration characteristics can be realized relatively easily.

The piezoelectric element 22 has a function of expanding and contracting by energization to bend and vibrate the vibrating arm 28 in the Z-axis direction. In addition, the piezoelectric element 23 has a function of expanding and contracting by energization to bend and vibrate the vibrating arm 29 in the Z-axis direction. The piezoelectric element 24 has a function of expanding and contracting by energization to bend and vibrate the vibrating arm 30 in the Z-axis direction.
As shown in FIG. 4B, the piezoelectric element 22 has a first electrode layer 221, a piezoelectric layer (piezoelectric thin film) 222, and a second electrode layer 223 in this order on the vibrating arm 28. It is laminated and configured. Similarly, the piezoelectric element 23 is configured by laminating a first electrode layer 231, a piezoelectric layer 232, and a second electrode layer 233 in this order on a vibrating arm 29. The piezoelectric element 24 is configured by laminating a first electrode layer 241, a piezoelectric layer 242, and a second electrode layer 243 in this order on the vibrating arm 30.

Hereinafter, each layer constituting the piezoelectric element 22 will be described in detail in order. Note that the configuration of each layer of the piezoelectric elements 23 and 24 is the same as that of the piezoelectric element 22, and therefore the description thereof is omitted.
[First electrode layer]
The first electrode layer 221 is provided on the vibrating arm 28 from the base portion 27 along the extending direction (Y-axis direction).

In the present embodiment, on the vibrating arm 28, the length of the first electrode layer 221 is shorter than the length of the vibrating arm 28.
In the present embodiment, the length of the first electrode layer 221 is set to about 2/3 of the length of the vibrating arm 28. The length of the first electrode layer 221 can be set to about 1/3 to 1 of the length of the vibrating arm 28.

Such a first electrode layer 221 includes 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) and other metal materials, indium tin oxide It can be formed of a conductive material such as (ITO).
Among them, as a constituent material of the first electrode layer 221, it is preferable to use a metal (gold, gold alloy) or platinum mainly made of gold, and a metal (especially gold) mainly made of gold. More preferred.
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. Furthermore, the orientation of the piezoelectric layer 222 can be improved by forming the first electrode layer 221 with gold or a gold alloy.

  The average thickness of the first electrode layer 221 is not particularly limited, but is preferably about 1 to 300 nm, and more preferably 10 to 200 nm, for example. This prevents the first electrode layer 221 from adversely affecting the driving characteristics of the piezoelectric element 22 and the vibration characteristics of the vibrating arm 28, and has excellent conductivity of the first electrode layer 221 as described above. Can be.

For example, when the first electrode layer 221 is made of gold and the vibration substrate 21 is made of quartz, their adhesion is low. Therefore, in such a case, it is preferable to provide an underlayer made of Ti, Cr, or the like between the first electrode layer 221 and the vibration substrate 21. Thereby, the adhesion between the underlayer and the vibrating arm 28 and the adhesion between the underlayer and the first electrode layer 221 can be made excellent. As a result, the first electrode layer 221 can be prevented from peeling from the vibrating arm, and the reliability of the vibrating piece 2 can be improved.
The average thickness of the underlayer can exert the effect of improving the adhesion as described above while preventing the underlayer from adversely affecting the driving characteristics of the piezoelectric element 22 and the vibration characteristics of the vibrating arm 28. Although it will not specifically limit if possible, For example, it is preferable that it is about 1-300 nm.

[Piezoelectric layer]
The piezoelectric layer 222 is provided on the first electrode layer 221 along the extending direction (Y-axis direction) of the vibrating arm 28.
In addition, the length of the piezoelectric layer 222 in the extending direction (Y-axis direction) of the vibrating arm 28 is substantially equal to the length of the first electrode layer 221 in the same direction (Y-axis direction).
Thereby, the orientation of the piezoelectric layer 222 can be enhanced by the surface state of the first electrode layer 221 as described above over the entire region of the piezoelectric layer 222 in the Y-axis direction. Therefore, the piezoelectric layer 222 can be homogenized in the longitudinal direction (Y-axis direction) of the vibrating arm 28.

  Further, the end portion on the base portion 27 side of the piezoelectric layer 222 (that is, the base end portion of the piezoelectric layer 222) is provided so as to straddle the boundary portion between the vibrating arm 28 and the base portion 27. Thereby, the driving force of the piezoelectric element 22 can be efficiently transmitted to the vibrating arm 28. In addition, a sudden change in rigidity at the boundary between the vibrating arm 28 and the base 27 can be mitigated. Therefore, the Q value of the resonator element 2 can be increased.

Examples of the constituent material (piezoelectric material) of the piezoelectric layer 222 include zinc oxide (ZnO), aluminum nitride (AlN), lithium tantalate (LiTaO ₃ ), lithium niobate (LiNbO ₃ ), and niobic acid. Examples include potassium (KNbO ₃ ), lithium tetraborate (Li ₂ B ₄ O ₇ ), barium titanate (BaTiO ₃ ), and PZT (lead zirconate titanate), but it is preferable to use AIN or ZnO.

Among these, it is preferable to use ZnO or AlN as the constituent material of the piezoelectric layer 222. ZnO (zinc oxide) and aluminum nitride (AlN) are excellent in c-axis orientation. Therefore, the CI value of the resonator element 2 can be reduced by configuring the piezoelectric layer 222 with ZnO as a main material. Moreover, these materials can be formed into a film by the reactive sputtering method.
The average thickness of the piezoelectric layer 222 is preferably 50 to 3000 [nm], and more preferably 100 to 2000 [nm]. Thereby, it is possible to improve the drive characteristics of the piezoelectric element 22 while preventing the piezoelectric layer 222 from adversely affecting the vibration characteristics of the vibrating arm 28.

[Second electrode layer]
The second electrode layer 223 is provided on the piezoelectric layer 222 along the extending direction (Y-axis direction) of the vibrating arm 28.
In addition, the length of the second electrode layer 223 in the extending direction (Y-axis direction) of the vibrating arm 28 is substantially equal to the length of the piezoelectric layer 222. Accordingly, the entire region of the piezoelectric layer 222 can be expanded and contracted in the extending direction (Y-axis direction) of the vibrating arm 28 by an electric field generated between the second electrode layer 223 and the first electrode layer 221 described above. it can. Therefore, vibration efficiency can be increased.

The second electrode layer 223 includes 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) and other metal materials, indium tin oxide It can be formed of a conductive material such as (ITO). In particular, as the constituent material of the second electrode layer 223, it is preferable to use gold (gold, gold alloy) or platinum, which is the main material of gold, as in the case of the first electrode layer 221, and metal which is mainly composed of gold. It is more preferable to use (especially gold).
The average thickness of the second electrode layer 223 is not particularly limited, but is preferably about 1 to 300 nm, and more preferably 10 to 200 nm, for example. This prevents the second electrode layer 223 from adversely affecting the drive characteristics of the piezoelectric element 22 and the vibration characteristics of the vibrating arm 28, and makes the conductivity of the second electrode layer 223 excellent. Can do.

Note that an insulating layer such as SiO ₂ (silicon oxide) or AlN (aluminum nitride) may be provided between the piezoelectric layer 222 and the second electrode layer 223 as necessary. This insulator layer has a function of protecting the piezoelectric layer 222 and preventing a short circuit between the first electrode layer 221 and the second electrode layer 223. The insulator layer may be formed so as to cover only the upper surface of the piezoelectric layer 222, or the upper surface of the piezoelectric layer 222 and the side surface of the piezoelectric layer 222 (other than the surface in contact with the first electrode layer 221). May also be formed so as to cover the surface.
The average thickness of the insulator layer is not particularly limited, but is preferably 50 to 500 nm. When the thickness is less than the lower limit value, the effect of preventing the short circuit as described above tends to be reduced. On the other hand, when the thickness exceeds the upper limit value, the characteristics of the piezoelectric element 22 are adversely affected. There is a fear.

In such a piezoelectric element 22, when a voltage is applied between the first electrode layer 221 and the second electrode layer 223, an electric field in the Z-axis direction is generated in the piezoelectric layer 222. Due to this electric field, the piezoelectric layer 222 expands or contracts in the Y-axis direction, causing the vibrating arm 28 to bend and vibrate in the Z-axis direction.
Similarly, in the piezoelectric element 23, when a voltage is applied between the first electrode layer 231 and the second electrode layer 233, the piezoelectric layer 232 expands or contracts in the Y-axis direction and vibrates. The arm 29 is bent and vibrated in the Z-axis direction. In the piezoelectric element 24, when a voltage is applied between the first electrode layer 241 and the second electrode layer 243, the piezoelectric layer 242 expands or contracts in the Y-axis direction, and the vibrating arm 30 is bent and vibrated in the Z-axis direction.

  In such piezoelectric elements 22, 23, and 24, the first electrode layers 221 and 231 described above are electrically connected to the second electrode layer 243 through a conduction portion that is not shown and includes a through electrode and a wiring. Has been. The second electrode layer 243 is electrically connected to a connection electrode 41 provided on the upper surface of the base portion 27 as shown in FIG. Thus, the first electrode layers 221 and 231 and the second electrode layer 243 are electrically connected to the connection electrode 41, respectively.

  In addition, the first electrode layer 241 is electrically connected to the second electrode layers 223 and 233 via a conduction portion including a through electrode and a wiring (not shown). The second electrode layers 223 and 233 are electrically connected to a connection electrode 42 provided on the upper surface of the base portion 27 via a wiring 43 as shown in FIG. Thereby, the first electrode layer 241 and the second electrode layers 223 and 233 are electrically connected to the connection electrode 42.

  The connection electrodes 41 and 42 and the wiring 43 are gold (Au), gold alloy, platinum (Pt), aluminum (Al), aluminum alloy, silver (Ag), silver alloy, chromium (Cr), chromium alloy, By metal materials such as copper (Cu), molybdenum (Mo), niobium (Nb), tungsten (W), iron (Fe), titanium (Ti), cobalt (Co), zinc (Zn), zirconium (Zr) Can be formed. Further, these can be formed simultaneously with the first electrode layers 221, 231, 241 or the second electrode layers 223, 233, 243.

  In the resonator element 2 having such a configuration, when a voltage (voltage for vibrating the vibrating arms 28, 29, 30) is applied between the connection electrode 41 and the connection electrode 42, the first electrode layer 221 and 231 and the second electrode layer 243, and the first electrode layer 241 and the second electrode layer 223 and 233 have opposite polarities, and the piezoelectric layers 222, 232, and 242 described above have Z An axial voltage is applied. Thereby, the vibrating arms 28, 29, and 30 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. 5, the vibrating arms 28 and 29 bend and vibrate in the same direction, and the vibrating arm 30 bends and vibrates in the direction opposite to the vibrating arms 28 and 29.

In this way, by causing the two adjacent vibrating arms to bend and vibrate in the opposite directions, leakage vibrations generated by the two adjacent vibrating arms 28, 30 and 29, 30 can be canceled out. As a result, vibration leakage can be prevented.
Further, when the vibrating arms 28, 29, 30 are flexibly vibrated, a voltage is generated between the connection electrodes 41, 42 at a certain frequency due to the piezoelectric effect of the piezoelectric material. Utilizing these properties, the resonator element 2 can generate an electrical signal that vibrates at a resonance frequency.

(Reinforcing member)
As described above, in the resonator element 2, when a voltage is applied between the connection electrode 41 and the connection electrode 42, the vibrating arms 28 and 29 bend and vibrate in the same direction, and the vibrating arm 30 is vibrated. , 29 bend and vibrate in the opposite direction. Here, when the resonator element 2 does not have the reinforcing members 51 to 53 (particularly the reinforcing members 51 and 52) as in the conventional resonator element, as shown in FIG. In the vibrating arms 28 and 29 positioned, torsional deformation occurs during the bending vibration.

This is presumed to be due to the following reason. The reason why torsional deformation occurs in the vibrating arms 28 and 29 is the same, and therefore, the vibrating arm 28 will be described below as a representative, and the description of the vibrating arm 29 will be omitted.
The vibrating arm 30 is positioned on one side of the vibrating arm 28 in the X-axis direction, whereas the vibrating arm is not positioned on the other side. That is, the configuration of the vibrating piece 2 is the same as that of the vibrating arm 28. It is asymmetric with respect to the axis, and the rigidity of the inner portion of the vibrating arm 28 (the first portion on the vibrating arm 30 side with respect to the axis Y1 of the vibrating arm 28) 28a is rigid on the outer portion (the axis Y1 of the vibrating arm 28). Than the rigidity of the second portion 28b on the opposite side of the vibrating arm 30). “Rigidity” in the present specification represents the difficulty of bending deformation of the vibrating arm 28 in the Z-axis direction, and the higher the rigidity, the more difficult the bending deformation in the Z-axis direction.

  Then, during bending vibration of the vibrating arm 28, the inner portion 28a having low rigidity is attracted to the central vibrating arm 30, thereby causing torsional deformation as shown in FIG. 6 along with bending vibration. The rigidity of the vibrating arm 28 does not change sharply at the boundary between the inner part 28a and the outer part 28b, but is opposite to the vibrating arm 30 of the outer part 28b from the vibrating arm 30 side of the inner part 28a. To gradually increase.

  In order to prevent or suppress such torsional deformation of the vibrating arms 28 and 29, in the resonator element 2, the rigidity of the inner portions 28 a and 29 a is set to the vibrating arms 28 and 29, and the outer portions 28 b and 28 b are set. It is higher than the rigidity. Specifically, in the X-axis direction, inner portions 28a, 29a of the vibrating arms 28, 29 are formed with portions whose rigidity is higher than the rigidity of the outer portions 28b, 29b. The rigidity of 29a is made higher than the rigidity of the outer portions 28b and 28b.

  In the present embodiment, the reinforcing member 51 is provided on the vibrating arm 28 to increase the rigidity of the inner portion 28 a, whereby the rigidity of the inner portion 28 a is made higher than the rigidity of the outer portion 28 b, and the reinforcing member is attached to the vibrating arm 29. 52 is provided so that the rigidity of the inner part 29a is higher than the rigidity of the outer part 29b. If such reinforcing members 51 and 52 are used, the rigidity of the inner portions 28a and 29a can be easily increased. Further, by appropriately selecting the material of the reinforcing members 51 and 52, the arrangement area (volume), and the like, the rigidity of the inner portions 28a and 29a can be easily increased to a required value.

  The vibrating arm 30 is sandwiched between the vibrating arms 28 and 29, and the configuration of the vibrating piece 2 is substantially symmetric with respect to the axis Y3 of the vibrating arm 30. The rigidity of the part and the rigidity of the part on the vibrating arm 29 side are substantially equal. Therefore, the torsional deformation as in the vibrating arms 28 and 29 does not substantially occur in the vibrating arm 30 during the bending vibration. In the present embodiment, the reinforcing member 53 is also provided in such a vibrating arm 30, but this means that the mass of the vibrating arm 30 (the mass including the reinforcing member 53 and the piezoelectric element 24) is the same as that of the vibrating arms 28 and 29. This is to make it close to the mass and to adjust the frequency of the vibrating arm 30.

Hereinafter, the reinforcing members 51, 52, and 53 will be described. Note that the reinforcing members 51 and 52 have the same configuration and are provided symmetrically with respect to the vibrating arm 30 (the axis Y3 of the vibrating arm 30). A description of the reinforcing member 52 will be omitted.
The vibrating arm 28 has a plate shape with a substantially uniform plate thickness, and a pair of plate surfaces constitute an upper surface 281 (first surface) and a lower surface 282 (second surface). The upper surface 281 is compressed or expanded by bending vibration of the vibrating arm 28 in the Z-axis direction, and the lower surface 282 is expanded when the upper surface 281 is compressed and compressed when the upper surface 281 is expanded. A reinforcing member 51 is provided on the upper surface 281 of the vibrating arm 28.

  Thus, by providing the reinforcing member 51 on the upper surface 281 (the surface on which the piezoelectric element 22 is provided), the reinforcing member 51 is simultaneously formed in the step of forming the piezoelectric element 22 as described later. Therefore, the reinforcing member 51 can be easily formed. Furthermore, in the present embodiment, the reinforcing member 51 is also used to adjust the resonance frequency of the vibrating arm 28 by reducing the mass by removing a part or all of the reinforcing member 51 by irradiation with energy rays. By providing the member 51 on the upper surface 281, the removal of the reinforcing member 51 at this time (irradiation with energy rays) can be easily performed. The reinforcing member 51 may be provided on the lower surface 282 instead of the upper surface 281, or may be provided on both the upper surface 281 and the lower surface 282.

Such a reinforcing member 51 is provided on a portion 281a (a region corresponding to the inner portion 28a) closer to the vibrating arm 30 than the axis Y1 of the vibrating arm 28 in a plan view of the upper surface 281. Thereby, the rigidity of the site | part 28a inside the vibrating arm 28 can be improved. As a result, torsional deformation of the vibrating arm 28 during bending vibration is prevented or suppressed, and the vibrating arm 28 can be vibrated smoothly and stably, and the vibration characteristics of the vibrating piece 2 are improved.
In the present embodiment, the reinforcing member 51 has a strip shape (rectangular shape) whose longitudinal direction is the Y-axis direction. However, the shape of the reinforcing member 51 is not particularly limited, and may be, for example, a shape in which a band-shaped corner portion is chamfered or an elliptical shape. Further, the reinforcing member 51 may have, for example, a plurality of parts divided in the Y-axis direction.

  The reinforcing member 51 is provided at the distal end portion (near the distal end) of the vibrating arm 28. Since the piezoelectric element 22 is not provided at the tip of the vibrating arm 28, it can be used effectively for installing the reinforcing member 51 (in other words, a sufficient installation space for the piezoelectric element 22 can be secured). ). Therefore, the vibration arm 28 can be shortened, and the vibration piece 2 can be downsized. Further, as described above, the reinforcing member 51 is also used to adjust the resonance frequency of the vibrating arm 28 by reducing the mass by removing a part or all of the reinforcing member 51 by irradiation with energy rays. By providing the reinforcing member 51 at the tip, the amount of change in the frequency (resonance frequency) of the vibrating arm 28 with respect to the amount of removal of the reinforcing member 51 can be increased. Therefore, frequency adjustment can be performed efficiently.

  The constituent material of the reinforcing member 51 (the same applies to the reinforcing members 52 and 53) is relatively hard (preferably higher than the Young's modulus of the constituent material of the vibration substrate 21), and is formed on the vibrating arm 28. The material is not particularly limited as long as it is possible, and a resin material, a metal material, a ceramic material, or the like can be used. Among these, it is particularly preferable that the film is formed by depositing a metal or ceramic.

  Metal or ceramics (insulating material) can be easily and accurately deposited by a vapor deposition method. A film (weight film) made of metal or ceramics can be easily and accurately removed by irradiation with energy rays (particularly laser). For this reason, by forming the reinforcing member 51 by depositing a metal or ceramic film, the frequency adjustment becomes easier and more accurate.

  As the metal material, gold (Au), a gold alloy, platinum (Pt), aluminum (Al), an aluminum alloy, silver (like the constituent materials of the first electrode layer 221 and the second electrode layer 223 described above) Ag), silver alloy, chromium (Cr), chromium alloy, copper (Cu), molybdenum (Mo), niobium (Nb), tungsten (W), iron (Fe), titanium (Ti), cobalt (Co), Examples thereof include zinc (Zn) and zirconium (Zr), and one or more of these can be used in combination. Among these, it is preferable to use Al, Cr, Fe, Ni, Cu, Ag, Au, Ti, Pt, or an alloy containing at least one of these as the metal material.

Further, as ceramics used for the constituent material of the reinforcing member 51, various glasses, alumina (aluminum oxide), silica (silicon oxide), titania (titanium oxide), zirconia, yttria, calcium phosphate and other oxide ceramics, silicon nitride, nitriding Nitride ceramics such as aluminum, titanium nitride and boron nitride, carbide ceramics such as graphite and tungsten carbide, and other ferroelectric materials such as barium titanate, strontium titanate, PZT, PLZT and PLLZT . Among these, it is preferable to use an insulating material such as silicon oxide (SiO ₂ ), titanium oxide (TiO ₂ ), aluminum oxide (Al ₂ O ₃ ) as the ceramic.

The reinforcing member 53 is provided on the upper surface 301 of the vibrating arm 30. Accordingly, the three reinforcing members 51, 52, 53 are provided on the surfaces corresponding to each other, and these reinforcing members 51, 52, 53 can be formed in the same process. Therefore, the manufacturing process of the resonator element 2 can be simplified.
The reinforcing member 53 is provided symmetrically with respect to the axis Y <b> 3 of the vibrating arm 30 at the center of the upper surface 301 of the vibrating arm 30 in the X-axis direction. Thereby, the rigidity of the part on the vibrating arm 28 side of the vibrating arm 30 and the rigidity of the part on the vibrating arm 29 side can be kept substantially equal. That is, by providing the reinforcing member 53, it is possible to effectively prevent the balance between the rigidity of the portion on the vibrating arm 28 side of the vibrating arm 30 and the rigidity of the portion on the vibrating arm 29 side from being lost.

  The reinforcing member 53 is provided at the distal end portion (near the distal end) of the vibrating arm 30. Since the piezoelectric element 24 is not provided at the tip of the vibrating arm 30, it can be used effectively for installing the reinforcing member 53. Therefore, the vibration arm 30 can be shortened, and the vibration piece 2 can be downsized. In addition, as described above, the reinforcing member 53 is also used to adjust the resonance frequency of the vibrating arm 30 by reducing the mass by removing a part or all of the reinforcing member 53 by irradiation with energy rays. By providing the reinforcing member 53 at the tip, the amount of change in the frequency (resonance frequency) of the vibrating arm 30 with respect to the amount of removal of the reinforcing member 53 can be increased. Therefore, frequency adjustment can be performed efficiently.

Further, it is preferable that the mass of the reinforcing member 53 before being partially removed by the energy ray irradiation is substantially equal to the mass of the reinforcing members 51 and 52 before being partially removed by the energy ray irradiation. . Accordingly, the mass of the vibrating arms 28, 29, and 30 (the mass including the piezoelectric element and the reinforcing member) can be made substantially equal to each other, and the vibrating arms 28, 29, and 30 can be vibrated more smoothly.
The configuration of the resonator element 2 has been described in detail above.

(Frequency adjustment method)
Next, a method for adjusting the frequency of the resonator element 2 configured as described above will be described. In the following, the frequency adjustment of the vibrating arm 28 will be described as a representative, but the frequency adjustment of the vibrating arms 29 and 30 is the same as the frequency adjustment of the vibrating arm 28.

First, the resonator element 2 before frequency adjustment (unadjusted) is prepared. At this time, the reinforcing member 51 as described above is provided on the vibrating arm 28. At this time, the frequency (resonance frequency) of the vibrating arm 28 is set to be lower than the target frequency (resonance frequency).
And a part of reinforcement member 51 is removed as needed by irradiation of energy rays. For example, when a part of the reinforcing member 51 is removed by laser light irradiation, the removed part of the reinforcing member 51 has a shape such as a line shape or a dot shape. Thereby, since the mass of the reinforcing member 51 decreases, the frequency of the vibrating arm 28 is increased.

  The energy ray used for such frequency adjustment is not particularly limited as long as it can remove the necessary portion of the reinforcing member 51 without adversely affecting the vibrating arm 28, and includes radiation, electron beam, laser, Examples of the ion beam include a carbon dioxide laser, an excimer laser, and a YAG laser. Thereby, a part of reinforcement member 51 can be removed by a desired amount easily and reliably.

(Manufacturing method of vibrating piece)
An example of a method for manufacturing the resonator element 2 will be briefly described.
The manufacturing method of the resonator element 2 includes: [A] forming the first electrode layers 221, 231, 241 and the reinforcing members 51, 52, 53 on the vibrating arms 28, 29, 30; [B] the first Steps of forming the piezoelectric layers 222, 232, 242 on the electrode layers 221, 231, 241 and [C] Steps of forming the second electrode layers 223, 233, 343 on the piezoelectric layers 222, 232, 242 And have.

Hereafter, each process is demonstrated easily.
[A]
First, a substrate for forming the vibration substrate 21 is prepared.
Then, the vibration substrate 21 is formed by etching the substrate.
More specifically, for example, when the substrate is a quartz substrate, the thin portion 271 of the quartz substrate is removed by anisotropic etching using BHF (buffer hydrogen fluoride) as an etching solution. Turn into. Thereafter, the thinned portion is partially removed by anisotropic etching similar to the above to form the vibrating arms 28, 29, and 30. Thereby, the vibration substrate 21 is formed.

  Thereafter, first electrode layers 221, 231, 241 and reinforcing members 51, 52, 53 are formed on the vibrating arms 28, 29, 30. At that time, wiring and the like are simultaneously formed as necessary. Examples of the method for forming the first electrode layers 221, 231, and 241 and the reinforcing members 51, 52, and 53 include physical film formation methods such as sputtering and vacuum vapor deposition, and chemical vapor deposition methods such as CVD (Chemical Vapor Deposition). There are various vapor deposition methods such as an inkjet method, and various coating methods such as an ink jet method, but it is preferable to use a vapor deposition method (particularly, sputtering method or vacuum deposition method). In forming the first electrode layers 221, 231 and 241, it is preferable to use a photolithography method. Note that the first electrode layers 221, 231 and 241 can be collectively formed in the same film formation step.

[B]
Next, piezoelectric layers 222, 232, and 242 are formed on the first electrode layers 221, 231, and 241. Examples of the method for forming the piezoelectric layers 222, 232, and 242 include physical film formation methods such as sputtering and vacuum vapor deposition, vapor phase film formation methods such as chemical vapor deposition such as CVD (Chemical Vapor Deposition), and the like. And various coating methods such as an ink jet method, but a vapor phase film forming method (particularly a reactive sputtering method) is preferably used. In forming (patterning) the piezoelectric layers 222, 232, and 242, it is preferable to use a photolithography method. Further, when patterning the piezoelectric layers 222, 232, and 242 it is preferable to use wet etching to remove unnecessary portions. Note that the piezoelectric layers 222, 232, and 242 can be collectively formed in the same film forming process.

[C]
Next, second electrode layers 223, 233 and 343 are formed on the piezoelectric layers 222, 232 and 242. At that time, the connection electrodes 41 and 42 are also formed at the same time. The formation of the second electrode layers 223, 233, and 343 can be performed in the same manner as the first electrode layers 221, 231, and 241 described above.
Thereafter, frequency adjustment as described above is performed as necessary. The frequency adjustment may be performed before the resonator element 2 is stored in the package 3 or may be performed after the resonator element 2 is stored in the package 3.

  As described above, the resonator element 2 can be manufactured. In the example of the manufacturing method described above, the reinforcing members 51, 52, and 53 are formed together with the first electrode layers 221, 231, and 241. However, the present invention is not limited to this, and for example, the second electrode layer 223 is formed. 233 and 243 may be formed together. The reinforcing members 51, 52, and 53 are formed by stacking a film formed by the first electrode layers 221, 231, and 241 and a film formed by forming the second electrode layers 223, 233, and 243. May be.

(package)
Next, the package 3 that houses and fixes the resonator element 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 which will be described later, and are joined by being integrally fired. The frame member 32 and the lid member 33 are joined by an adhesive or a brazing material. The package 3 houses the resonator element 2 in an internal space S defined by the base substrate 31, the frame member 32, and the lid member 33. In addition to the resonator element 2, an electronic component (oscillation circuit) for driving the resonator element 2 can be accommodated in the package 3.

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.
Moreover, as a constituent material of the frame member 32 and the lid member 33, the same constituent material as the base substrate 31, various metal materials such as Al and Cu, various glass materials, and the like can be used, for example. In particular, when a material having light transmissivity such as a glass material is used as the constituent material of the lid member 33, the mass described above via the lid member 33 even after the resonator element 2 is accommodated in the package 3. The frequency of the resonator element 2 can be adjusted by irradiating the part with laser and removing the metal coating part to reduce the mass of the resonator element 2 (by a mass reduction method).

On the upper surface of the base substrate 31, the above-described vibrating piece 2 is fixed via a fixing material 36. The fixing material 36 is made of, for example, an epoxy, polyimide, or silicone adhesive. In such a fixing material 36, an uncured (unsolidified) adhesive is applied onto the base substrate 31, and the vibration piece 2 is placed on the adhesive, and then the adhesive is cured or solidified. Is formed. Thereby, the resonator element 2 (base portion 27) is securely fixed to the base substrate 31.
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.

In addition, a pair of electrodes 35 a and 35 b are formed on the upper surface of the base substrate 31 so as to be exposed to the internal space S.
The electrode 35a is electrically connected to the connection electrode 42 described above via, for example, a metal wire (bonding wire) 38 formed by a wire bonding technique. The electrode 35b is electrically connected to the connection electrode 41 described above via a metal wire (bonding wire) 37 formed by, for example, a wire bonding technique.

In addition, the connection method of a pair of electrode 35a, 35b and the connection electrodes 41 and 42 is not limited to this, For example, you may carry out with a conductive adhesive. In this case, for example, the front and back of the vibrating piece 2 may be reversed, or the connection electrodes 41 and 42 may be formed on the lower surface of the vibrating piece 2.
Further, four external terminals 34 a, 34 b, 34 c, 34 d are provided on the lower surface of the base substrate 31.

  Out of these four external terminals 34a to 34d, the external terminals 34a and 34b are electrically connected to the electrodes 35a and 35b through conductor posts (not shown) provided in via holes formed in the base substrate 31, respectively. It is a connected hot terminal. Further, the other two external terminals 34c and 34d are used to increase the bonding strength and to equalize the distance between the package 3 and the mounting board when the package 3 is mounted on the mounting board, respectively. Dummy terminal.

Such 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.
When an electronic component is housed inside the package 3, the lower surface of the base substrate 31 can be used to check the characteristics of the electronic component and various information in the electronic component (for example, temperature compensation information of the vibrator) as necessary. A write terminal for rewriting (adjustment) may be formed.

According to the first embodiment as described above, the reinforcing members 51 and 52 are provided on the vibrating arms 28 and 29, thereby preventing or suppressing the torsional deformation of the vibrating arms 28 and 29, and the unintentional vibration mode. Thus, the vibrating arms 28, 29, and 30 can be smoothly bent and vibrated without generating. Therefore, the resonator element 2 that can exhibit excellent vibration characteristics is obtained.
Further, the vibrator 1 including such a vibrating piece 2 is excellent in reliability.

Second Embodiment
Next, a second embodiment of the present invention will be described.
FIG. 7 is a partially enlarged cross-sectional view for explaining a reinforcing member according to the second embodiment of the present 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 reinforcing member 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, the reinforcing members provided on the vibrating arms 28 will be representatively described, but the same applies to the reinforcing members provided on the vibrating arms 29 and 30.

As shown in FIG. 7, a reinforcing member 51 </ b> A is provided on the upper surface 281 of the vibrating arm 28. The reinforcing member 51 </ b> A is formed integrally with the first electrode layer 221 of the piezoelectric element 22. Thereby, since the reinforcing member 51 can be formed simultaneously with the first electrode layer 221 (in the same process), the manufacture of the resonator element 2 can be facilitated.
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 present invention will be described.
FIG. 8 is a cross-sectional view for explaining a reinforcing member according to the third embodiment of the present invention. 8 corresponds to a cross-sectional view taken along the line AA in FIG.
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 reinforcing member is different. In FIG. 8, the same components as those in the above-described embodiment are denoted by the same reference numerals. In the present embodiment, the reinforcing member 51B provided on the vibrating arm 28 will be representatively described, but the same applies to the reinforcing members 52B and 53B provided on the vibrating arms 29 and 30.

  As shown in FIG. 8, the reinforcing member 51 </ b> B includes a first reinforcing member 511 </ b> B provided on the upper surface 281 of the vibrating arm 28 and a second reinforcing member 512 </ b> B provided on the lower surface 282. Thus, by providing the reinforcing members 51B on both surfaces of the vibrating arm 28, the bending deformation to the upper side in FIG. 8 and the bending deformation to the lower side in FIG. The arm 28 can be bent and vibrated.

The first reinforcing member 511B and the second reinforcing member 512B are preferably formed symmetrically via the vibrating arm 28, and are preferably made of the same material. Thereby, the effect mentioned above becomes more remarkable.
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 present invention will be described.
FIG. 9 is a cross-sectional view for explaining a reinforcing member according to the fourth embodiment of the present invention. FIG. 9 corresponds to a cross-sectional view taken along line AA in FIG.
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 configuration of the reinforcing members provided on the vibrating arms 28 and 29 is different. In FIG. 9, the same reference numerals are given to the same configurations as those in the above-described embodiment. In the present embodiment, the reinforcing member 51 </ b> C provided on the vibrating arm 28 is representatively described, but the same applies to the reinforcing member 52 </ b> C provided on the vibrating arm 29.

  As shown in FIG. 9, a reinforcing member 51 </ b> C is provided on the upper surface 281 of the vibrating arm 28. The reinforcing member 51C is provided over the entire area of the upper surface 281 in the X-axis direction, that is, straddling the inner part 28a and the outer part 28b. Further, the thickness (average thickness) of the region 511C corresponding to the inner portion 28a of the reinforcing member 51C is thicker than the thickness (average thickness) of the region 512C corresponding to the outer portion 28b. The thicknesses of the regions 511C and 512C are substantially uniform, and a step is formed at the boundary between the regions 511C and 512C.

  According to such a reinforcing member 51C, the rigidity of the inner portion 28a of the vibrating arm 28 and the rigidity of the outer portion 28b are increased, but due to the difference in thickness of the regions 511C and 512C, the inner portion 28a of the vibrating arm 28 is increased. The amount of increase in the stiffness of is greater than the amount of increase in the stiffness of the outer portion 28b. Therefore, according to such a reinforcing member 51C, the rigidity of the inner part 28a of the vibrating arm 28 can be made higher than the rigidity of the outer part 28b.

The reinforcing member 51C includes a first layer formed over the entire area of the upper surface 281 in the X-axis direction and a second layer formed corresponding to the inner portion 28a. With such a configuration, the reinforcing member 51C can be easily formed. Specifically, the first layer is formed simultaneously with the first electrode layer 221 (in the same process), and the second layer is formed simultaneously with the second electrode layer 223 (in the same process), thereby reinforcing the first layer. The member 51C can be easily formed.
According to the fourth embodiment as described above, the same effects as those of the first embodiment described above can be obtained.

<Fifth Embodiment>
Next, a fifth embodiment of the present invention will be described.
FIG. 10 is a cross-sectional view for explaining a reinforcing member according to a fifth embodiment of the present invention. 10 corresponds to the cross-sectional view taken along the line AA in FIG.
Hereinafter, the fifth embodiment will be described with a focus on differences from the above-described embodiments, and description of similar matters will be omitted.

  The fifth embodiment is substantially the same as the first embodiment except that the configuration of the reinforcing members provided on the vibrating arms 28 and 29 is different. In FIG. 10, the same components as those in the above-described embodiment are denoted by the same reference numerals. In this embodiment, the reinforcing member 51D provided on the vibrating arm 28 will be described as a representative example, but the same applies to the reinforcing member 52D provided on the vibrating arm 29.

  As shown in FIG. 10, a reinforcing member 51 </ b> D is provided on the upper surface 281 of the vibrating arm 28. Such a reinforcing member 51D is provided over the entire area of the upper surface 281 in the X-axis direction, that is, across the inner part 28a and the outer part 28b. Further, the thickness of the reinforcing member 51D gradually decreases from the right side in FIG. 10 toward the left side (that is, from the vibrating arm 30 side to the opposite side). Accordingly, the average thickness of the region 511D corresponding to the inner portion 28a of the reinforcing member 51D is larger than the average thickness of the region 512D corresponding to the outer portion 28b.

  According to such a reinforcing member 51D, the rigidity of the inner portion 28a of the vibrating arm 28 and the rigidity of the outer portion 28b are increased, but due to the difference in thickness of the regions 511D and 512D, the inner portion 28a of the vibrating arm 28 is increased. The amount of increase in the stiffness of is greater than the amount of increase in the stiffness of the outer portion 28b. Therefore, according to such a reinforcing member 51D, the rigidity of the inner part 28a of the vibrating arm 28 can be made higher than the rigidity of the outer part 28b.

Furthermore, according to the reinforcing member 51D, the rigidity of the vibrating arm 28 can be gradually (continuously) changed from the right side to the left side in FIG. Therefore, the vibrating arm 28 can be vibrated more smoothly.
The fifth embodiment as described above can achieve the same effects as those of the first embodiment described above.

<Sixth Embodiment>
Next, a sixth embodiment of the present invention will be described.
FIG. 11 is a top view showing a vibrator according to the sixth embodiment of the present invention, and FIG. 12 is a cross-sectional view taken along the line CC in FIG.
Hereinafter, the sixth embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted.

  The sixth embodiment is substantially the same as the first embodiment except that the configuration of the reinforcing members provided on the vibrating arms 28 and 29 is different. In FIG. 11, the same reference numerals are given to the same components as those in the above-described embodiment. In the present embodiment, the reinforcing member 51E provided on the vibrating arm 28 will be representatively described, but the same applies to the reinforcing member 52E provided on the vibrating arm 29.

  As shown in FIGS. 11 and 12, a reinforcing member 51E is provided on a side surface (third surface) 283 that connects the upper surface 281 and the lower surface 282 of the vibrating arm 28 on the vibrating arm 30 side. According to such a reinforcing member 51E, the rigidity of the portion 28a inside the vibrating arm 28 can be increased. Therefore, the rigidity of the inner part 28a of the vibrating arm 28 can be made higher than the rigidity of the outer part 28b.

Here, the side surface 283 is a surface on which no member (piezoelectric element 22) other than the reinforcing member 51E is provided. By providing the reinforcing member 51E on the side surface 283, the area (volume) of the reinforcing member 51E can be increased without hindering the arrangement of other members such as the piezoelectric element 22. In particular, since the reinforcing member 51E can be formed up to the base end of the vibrating arm 28 (connection portion with the base 27), the rigidity of the portion 28a inside the vibrating arm 28 can be increased more effectively.
The sixth embodiment as described above can achieve the same effects as those of the first embodiment described above.

<Seventh embodiment>
Next, a seventh embodiment of the present invention will be described.
FIG. 13 is a partially enlarged perspective view of the vibrator according to the seventh embodiment of the invention.
Hereinafter, the seventh embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted.

  The seventh embodiment is substantially the same as the first embodiment except that the method for increasing the rigidity of the portions inside the vibrating arms 28 and 29 is different. In FIG. 13, the same reference numerals are given to the same components as those in the above-described embodiment. In the present embodiment, the method for increasing the rigidity of the portion inside the vibrating arm 28 will be described as a representative example, but the same applies to the method for increasing the rigidity of the portion inside the vibrating arm 29.

As shown in FIG. 13, the thickness of the tip portion of the vibrating arm 28 (the portion on the tip side of the piezoelectric element 22) is from left to right in FIG. 13 (from the vibrating arm 30 side in the X-axis direction to the opposite direction). To)) gradually decreasing. That is, the cross-sectional shape of the vibrating arm 28 has a trapezoidal shape with the side surface 283 as the bottom. Further, the thickness of the left end in FIG. 13 of the distal end portion of the vibrating arm 28 is equal to the thickness on the proximal end side, and the thickness on the right end in FIG. Thinner than that.
By making the vibrating arm 28 in such a shape, the average thickness of the outer portion 28b of the distal end portion of the vibrating arm 28 becomes thinner than the average thickness of the inner portion 28a. The rigidity can be lowered. Therefore, the rigidity of the inner part 28a of the vibrating arm 28 can be made higher than the rigidity of the outer part 28b.

According to such a method, since it is not necessary to provide a separate member in the vibrating arm 28 as in the first to sixth embodiments described above, the configuration of the vibrating piece 2 can be simplified.
In particular, according to the present embodiment, the rigidity of the vibrating arm 28 can be gradually (continuously) changed from the left side to the right side in FIG. 13, so that the stress concentration during bending vibration of the vibrating arm 28 is effective. Can be prevented or suppressed.
In addition, by making only the tip of the vibrating arm 28 have a trapezoidal cross-sectional shape, the region of the upper surface 281 where the piezoelectric element 22 is provided can be kept parallel to the XY plane. Thereby, the bending vibration of the vibrating arm 28 in the Z-axis direction can be performed smoothly.
According to the seventh embodiment as described above, the same effects as those of the first embodiment described above can be obtained.
In the present embodiment, the vibrating arms 28, 29, 30 may be separately provided with a weight portion for frequency adjustment.

<Eighth Embodiment>
Next, an eighth embodiment of the present invention will be described.
FIG. 14 is a partially enlarged perspective view of the vibrator according to the eighth embodiment of the invention.
Hereinafter, the eighth embodiment will be described with a focus on differences from the above-described embodiments, and description of similar matters will be omitted.

  The eighth embodiment is substantially the same as the first embodiment except that the method for increasing the rigidity of the portions inside the vibrating arms 28 and 29 is different. In FIG. 14, the same reference numerals are given to the same components as those in the above-described embodiment. In the present embodiment, the method for increasing the rigidity of the portion inside the vibrating arm 28 will be described as a representative example, but the same applies to the method for increasing the rigidity of the portion inside the vibrating arm 29.

  As shown in FIG. 14, the thickness of the tip of the vibrating arm 28 gradually decreases from the left side to the right side in FIG. 14 (from the vibrating arm 30 side in the X-axis direction to the opposite direction). That is, the cross-sectional shape of the vibrating arm 28 has a trapezoidal shape with the side surface 283 as the bottom. Further, the thickness of the left end in FIG. 14 of the distal end portion of the vibrating arm 28 is thicker than the thickness on the base end side, and the thickness of the right end in FIG. Is equal. Therefore, the distal end portion of the vibrating arm 28 has a portion that protrudes in the Z-axis direction from a portion closer to the proximal end than that.

  By making the vibrating arm 28 in such a shape, the average thickness of the inner portion 28a of the distal end portion of the vibrating arm 28 becomes thicker than the average thickness of the outer portion 28b. The rigidity can be increased. Therefore, the rigidity of the inner part 28a of the vibrating arm 28 can be made higher than the rigidity of the outer part 28b.

According to such a method, since it is not necessary to provide a separate member in the vibrating arm 28 as in the first to sixth embodiments described above, the configuration of the vibrating piece 2 can be simplified.
In particular, according to the present embodiment, the rigidity of the vibrating arm 28 can be gradually (continuously) changed from the left side to the right side in FIG. 14, so that stress concentration during bending vibration of the vibrating arm 28 is effective. Can be prevented or suppressed.
In addition, by making only the tip of the vibrating arm 28 have a trapezoidal cross-sectional shape, the region of the upper surface 281 where the piezoelectric element 22 is provided can be kept parallel to the XY plane. Thereby, the bending vibration of the vibrating arm 28 in the Z-axis direction can be performed smoothly.
According to the eighth embodiment as described above, the same effects as those of the first embodiment described above can be obtained.

<Ninth Embodiment>
Next, a ninth embodiment of the present invention will be described.
FIG. 15 is a partially enlarged perspective view of the vibrator according to the ninth embodiment of the invention.
Hereinafter, the ninth embodiment will be described with a focus on differences from the above-described embodiments, and description of similar matters will be omitted.

  The ninth embodiment is substantially the same as the first embodiment except that the method for increasing the rigidity of the portions inside the vibrating arms 28 and 29 is different. In FIG. 15, the same reference numerals are given to the same components as those in the above-described embodiment. In the present embodiment, the method for increasing the rigidity of the portion inside the vibrating arm 28 will be described as a representative example, but the same applies to the method for increasing the rigidity of the portion inside the vibrating arm 29.

  As shown in FIG. 15, the thickness of the inner portion 28a and the outer portion 28b is different at the tip of the vibrating arm 28. Specifically, the inner part 28a is thicker than the outer part 28b, and the thickness of the inner part 28a is equal to the thickness of the proximal end side, and the outer part 28a is thicker. The thickness of 28b is thinner than the thickness of the base end side. The thicknesses of the inner part 28a and the outer part 28b are substantially uniform, and a step is formed at the boundary between the inner part 28a and the outer part 28b.

  By making the vibrating arm 28 in such a shape, the average thickness of the outer portion 28b of the distal end portion of the vibrating arm 28 becomes thinner than the average thickness of the inner portion 28a. The rigidity can be lowered. Therefore, the rigidity of the inner part 28a of the vibrating arm 28 can be made higher than the rigidity of the outer part 28b.

According to such a method, since it is not necessary to provide a separate member in the vibrating arm 28 as in the first to sixth embodiments described above, the configuration of the vibrating piece 2 can be simplified.
In particular, in this embodiment, a pair of recessed portions having the same shape from the upper surface 281 and the lower surface 282 are formed in the portion 28b outside the tip of the vibrating arm 28, so that the vibrating arm 28 bends and vibrates more smoothly. be able to.
The ninth embodiment as described above can achieve the same effects as those of the first embodiment described above.

<Tenth Embodiment>
Next, a tenth embodiment of the present invention will be described.
FIG. 16 is a partially enlarged perspective view of the vibrator according to the tenth embodiment of the invention.
Hereinafter, the tenth embodiment will be described with a focus on differences from the above-described embodiments, and description of similar matters will be omitted.

  The tenth embodiment is substantially the same as the first embodiment except that the method for increasing the rigidity of the portions inside the vibrating arms 28 and 29 is different. In FIG. 16, the same reference numerals are given to the same components as those in the above-described embodiment. In the present embodiment, the method for increasing the rigidity of the portion inside the vibrating arm 28 will be described as a representative example, but the same applies to the method for increasing the rigidity of the portion inside the vibrating arm 29.

As shown in FIG. 16, at the tip of the vibrating arm 28, the inner portion 28a and the outer portion 28b have different thicknesses. Specifically, the inner part 28a is thicker than the outer part 28b, and the inner part 28a is thicker than the base end side, and the outer part 28a is thicker than the outer part 28b. The thickness of 28b is equal to the thickness of the proximal end side. Further, the thicknesses of the inner part 28a and the outer part 28b are substantially uniform, and a step is formed at the boundary between the inner part 28a and the outer part 28b.
By making the vibrating arm 28 in such a shape, the average thickness of the inner portion 28a of the distal end portion of the vibrating arm 28 becomes thicker than the average thickness of the outer portion 28b. The rigidity can be increased. Therefore, the rigidity of the inner part 28a of the vibrating arm 28 can be made higher than the rigidity of the outer part 28b.

According to such a method, since it is not necessary to provide a separate member in the vibrating arm 28 as in the first to sixth embodiments described above, the configuration of the vibrating piece 2 can be simplified.
In particular, in the present embodiment, the pair of convex portions protruding from the upper surface 281 and the lower surface 282 having the same shape are formed in the portion 28a inside the distal end portion of the vibrating arm 28, so that the vibrating arm 28 bends and vibrates more smoothly. be able to.
According to the tenth embodiment as described above, the same effects as those of the first embodiment described above can be obtained.

<Eleventh embodiment>
Next, an eleventh embodiment of the present invention will be described.
FIG. 17 is a cross-sectional view for explaining the vibrator according to the eleventh embodiment of the present invention. FIG. 17 corresponds to a cross-sectional view taken along line AA in FIG.
Hereinafter, the eleventh embodiment will be described with a focus on differences from the above-described embodiments, and description of similar matters will be omitted.

  The eleventh embodiment is substantially the same as the first embodiment except that the method for increasing the rigidity of the portions inside the vibrating arms 28 and 29 is different. In FIG. 17, the same reference numerals are given to the same configurations as those in the above-described embodiment. In the present embodiment, the method for increasing the rigidity of the portion inside the vibrating arm 28 will be described as a representative example, but the same applies to the method for increasing the rigidity of the portion inside the vibrating arm 29.

  As shown in FIG. 17, a plurality of through holes (defects) 281 b penetrating in the thickness direction (Z-axis direction) are formed in a portion 28 b outside the distal end portion of the vibrating arm 28. In the present embodiment, each through-hole 281b has a cylindrical shape and is aligned with the same shape and size. By forming such a through hole 281b, the rigidity of the portion 28b outside the vibrating arm 28 can be reduced. Therefore, the rigidity of the inner part 28a of the vibrating arm 28 can be made higher than the rigidity of the outer part 28b.

According to such a method, since it is not necessary to provide a separate member in the vibrating arm 28 as in the first to sixth embodiments described above, the configuration of the vibrating piece 2 can be simplified. In particular, in the present embodiment, by adjusting the number and size of the through holes 281b, the rigidity of the portion 28b outside the vibrating arm 28 can be easily lowered to a predetermined value. Further, since the through-hole 281b penetrating in the thickness direction can be easily formed by etching or the like, the manufacturing of the resonator element 2 can be facilitated by making the defective portion the through-hole 281b.
According to the eleventh embodiment as described above, the same effects as those of the first embodiment described above can be obtained.
The resonator element of each embodiment as described above can be applied to various electronic devices, and the obtained electronic device has high reliability.

Here, an electronic device including the resonator element according to the invention will be described in detail with reference to FIGS.
FIG. 18 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 has a built-in vibrator 1 that functions as a filter, a resonator, a reference clock, and the like.

FIG. 19 is a perspective view illustrating a configuration of a mobile phone (including PHS) to which an electronic device including the resonator element according to 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 vibrator 1 that functions as a filter, a resonator, and the like.

FIG. 20 is a perspective view illustrating a configuration of a digital still camera to which an electronic device including the resonator 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 a vibrator 1 that functions as a filter, a resonator, or the like.

  In addition to the personal computer of FIG. 18 (mobile personal computer), the mobile phone of FIG. 19, 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 (E.g., vehicle, aircraft, Instruments of 舶), can be applied to a flight simulator or the like.

  As described above, the resonator element, the vibrator, the vibration device, and the electronic apparatus according to the invention have been described based on the illustrated embodiment, but the invention is not limited thereto, and the configuration of each part has the same function. It can be replaced with one having any structure. Further, the present invention may be a combination of any two or more configurations (features) of the above embodiments. Further, in the above-described embodiment, an example in which the reinforcing member is irradiated with energy rays to adjust the frequency has been described. However, the present invention is not limited thereto, and the mass of the reinforcing member may be reduced by ion etching, sand blasting, or wet etching. .

For example, in the above-described embodiment, the case where the vibrating piece has three vibrating arms has been described as an example, but the number of vibrating arms may be two, or may be four or more.
In addition, the resonator device of the present invention has a crystal oscillator (SPXO), a voltage controlled crystal oscillator (VCXO), a temperature compensated crystal oscillator (TCXO), and a crystal oscillator with a thermostat (OCXO) by connecting an oscillation circuit to the resonator element. In addition to piezoelectric oscillators, etc., it is applied to gyro sensors and the like.

  DESCRIPTION OF SYMBOLS 1 ... vibrator 2 ... vibration piece 3 ... package 21 ... vibration board 22 ... piezoelectric element 23 ... piezoelectric element 24 ... piezoelectric element 27 ... base 28 ... vibration arm 28a ... inside Part 28b ... Outer part 29 ... Vibrating arm 29a ... Inside part 29b ... Outer part 30 ... Vibrating arm 31 ... Base substrate 32 ... Frame member 33 ... Lid member 34a, 34b, 34c 34d ... External terminal 35a ... Electrode 35b ... Electrode 36 ... Fixing material 37 ... Metal wire 38 ... Metal wire 41 ... Connection electrode 42 ... Connection electrode 43 ... Wiring 51 ... Reinforcing member 51A ... ... Reinforcing member 51B ... Reinforcing member 51C ... Reinforcing member 51D ... Reinforcing member 51E ... Reinforcing member 52 ... Reinforcing member 52B ... Reinforcing member 52C ... Reinforcing member 5 D ... Reinforcing member 52E ... Reinforcing member 53 ... Reinforcing member 53B ... Reinforcing member 100 ... Display part 221 ... First electrode layer 222 ... Piezoelectric layer 223 ... Second electrode layer 231 ... First electrode layer 232 ... Piezoelectric layer 233 ... Second electrode layer 241 ... Electrode layer 242 ... Piezoelectric layer 243 ... Electrode layer 271 ... Thin part 272 ... Thick part 281 ... Upper surface 281a ... part 281b ... through hole 282 ... bottom face 283 ... side face 291 ... top face 301 ... top face 511B ... first reinforcing member 511C ... area 511D ... area 512B ... second reinforcing member 512C Area 512D Area 1100 Personal computer 1102 Keyboard 1104 Main unit 1106 Display unit 1200 Band phone 1202 ... Operation button 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 S Internal space Y1 Axis Y3 Axis

Claims (8)

A base provided on a plane including a first direction and a second direction orthogonal to the first direction;
A plurality of vibrating arms extending in the first direction from the base and provided side by side in the second direction;
Each of the vibrating arms bends and vibrates in the normal direction of the plane,
The plurality of resonating arms include a pair of outer resonating arms located at both ends in the second direction,
Each of the outer vibrating arms includes a first portion located on the other outer vibrating arm side by a line that bisects the width of the outer vibrating arm in the second direction, and the other outer vibrating arm. The resonator element according to claim 1, wherein when the first part is divided into a second part located on the opposite side, the first part has a portion having higher rigidity than the second part.   2. The resonator element according to claim 1, wherein the first part of each of the outer vibrating arms has a thicker part than the second part. Each of the outer vibrating arms includes a first surface that is compressed or expanded by the bending vibration, and a second surface that is expanded when the first surface is compressed and compressed when the first surface is expanded. And a third surface connecting the first surface and the second surface,
The vibration according to claim 1, wherein a reinforcing member is provided in the first portion of at least one of the first surface, the second surface, and the third surface. Piece.   The resonator element according to claim 3, wherein the reinforcing member is provided at a tip portion of each of the outer vibrating arms. The reinforcing member is configured by using any one of SiO ₂ , Al, Al ₂ O ₃ , TiO ₂ , Cr, Fe, Ni, Cu, Ag, Au, Ti, and Pt. 5. The resonator element according to 3 or 4. A vibrating piece according to any one of claims 1 to 5,
And a package containing the resonator element. A vibrating piece according to any one of claims 1 to 5,
And an oscillation circuit connected to the resonator element.   An electronic apparatus comprising the resonator element according to claim 1.

Images