JP2004349856A - Piezoelectric vibrating reed, piezoelectric device using the piezoelectric vibrating reed, mobile phone device using the piezoelectric device, and electronic equipment using the piezoelectric device - Google Patents

Abstract

A piezoelectric vibrating reed having excellent shock resistance, capable of improving vibration efficiency and suppressing a CI value, a piezoelectric device in which the piezoelectric vibrating reed is housed in a package, and a mobile phone and an electronic device using the piezoelectric device. Providing equipment.
A whole is formed of a piezoelectric material, and has a base portion and a plurality of vibrating arms extending in parallel from the base portion, and each of the vibrating arms is formed with a groove portion extending in a longitudinal direction. The piezoelectric vibrating reeds, wherein the grooves are formed in the wall portions 22, 22, 23, 23 provided on both sides of the groove bottom portions in correspondence with the regions where the distortion during bending vibration of the plurality of vibrating arms increases. The wall thickness is increased.
[Selection diagram] FIG.

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a piezoelectric vibrating reed, a piezoelectric device in which the piezoelectric vibrating reed is housed in a package, and a mobile phone and an electronic device using the piezoelectric device.
[0002]
[Prior art]
In a small information device such as a hard disk drive (HDD), a mobile computer, or an IC card, or a mobile communication device such as a mobile phone, a car phone, or a paging system, a crystal in which a piezoelectric vibrating piece is housed in a package. Piezoelectric devices such as vibrators and crystal oscillators are widely used.
FIG. 8 is a schematic plan view showing a known configuration example of a piezoelectric vibrating reed used in such a piezoelectric device (see Patent Document 1). FIG. 9 is a sectional view taken along line AA of FIG.
[0003]
In FIG. 8, the piezoelectric vibrating reed 1 is formed by processing a quartz crystal wafer made of, for example, a single crystal of quartz into a tuning fork shape as illustrated by etching.
That is, the piezoelectric vibrating reed 1 is composed of a tuning fork type quartz piece including a base 5 and a pair of vibrating arms 6 and 7 extending in parallel from the base 5.
[0004]
The base 5 of the piezoelectric vibrating reed 1 is fixed to an electrode (not shown) on the package side. As can be understood with reference to FIGS. 8 and 9, grooves 4 and 5 extending in the length direction are formed on the front and back surfaces of the vibrating arms 6 and 7, respectively. Driving electrodes (not shown) are formed in the grooves 4 and 5. Notches 5a and 5b are provided on the outer edge of the base 51 in the width direction near the ends on the vibrating arms 6 and 7 side.
[0005]
In such a piezoelectric vibrating reed 1, a portion of a lead electrode (not shown) provided on the base portion 51 is fixed to a package-side electrode (not shown) with a conductive adhesive or the like, so that the piezoelectric vibrating reed 1 is provided from the package side A driving voltage is applied to the driving electrodes formed in the grooves 4 and 5 via the extraction electrodes.
As a result, the vibrating arms 6 and 7 make the distal ends 6a and 7a approach and separate from each other, and bend and vibrate as shown by arrows in FIG. By extracting a vibration frequency based on such vibration, it is used for various signals such as a control clock signal.
[0006]
[Patent Document 1] JP-A-2002-261575
[0007]
[Problems to be solved by the invention]
By the way, when the piezoelectric vibrating reed 1 having such a structure bends and vibrates as shown by an arrow in FIG. 8, a strain distribution is generated as shown in FIG.
That is, FIG. 10 is an analysis diagram simulating the distortion generated when the piezoelectric vibrating reed 1 undergoes bending vibration, and the regions where the distortion is larger in the order of reference signs a, b, and c are shown. That is, the region a has the largest distortion, and the region c has the smallest distortion.
[0008]
According to FIG. 10, there is a region with large distortion in the vibrating arms 6 and 7 that bend and vibrate. Therefore, providing a driving electrode in the groove provided in this region requires energy for driving in the region with large distortion. It is preferable because it can be supplied.
However, according to FIG. 10, it is understood that there is an area where a large distortion is generated at the roots of the vibrating arms 6 and 7 close to the crotch 8 between the vibrating arms 6 and 7.
For this reason, when the piezoelectric vibrating reed 1 or a piezoelectric device (not shown) containing the same in a package falls or receives an impact from the outside, the vibrating arms 6 and 7 are displaced, and the vibrating arms are displaced. A large stress acts on the root regions 6 and 7, and the grooves 4 and 5 provided in this region described in FIGS. 8 and 9 may be damaged if the thickness of the walls on both sides sandwiching the groove bottom is small. There is a problem that there is.
[0009]
The present invention uses a piezoelectric vibrating reed having excellent shock resistance, capable of increasing vibration efficiency and suppressing a CI (crystal impedance) value, a piezoelectric device containing the piezoelectric vibrating reed in a package, and a piezoelectric device. It is an object to provide a mobile phone and an electronic device.
[0010]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a piezoelectric device including a base portion, a base portion, and a plurality of vibrating arms extending in parallel from the base portion. Wherein the groove increases the wall thickness of the wall provided on both sides of the groove bottom corresponding to the region where the distortion during bending vibration of the plurality of vibrating arms increases. This is achieved by a piezoelectric vibrating reed, as described above.
According to the configuration of the first aspect, the groove portion has a wall thickness of a wall portion provided on both sides of the groove bottom portion corresponding to a region where distortion is large when the plurality of vibrating arms of the piezoelectric vibrating piece bends and vibrates. The thickness is increased. Therefore, not only at the time of bending vibration but also when an external impact is applied, a region where the stress is concentrated is structurally strengthened, so that the impact resistance is improved. Further, even if each vibrating arm and the groove portion are lengthened and the vibrating arm is largely shaken during bending vibration, there is no fear of breakage. Alternatively, in order to vibrate in the same manner as in the related art, only a small driving voltage is required, so that a piezoelectric vibrating reed having a low CI value can be realized.
Thus, according to the present invention, it is possible to exhibit an effect that the shock resistance is excellent, the vibration efficiency is increased, and the CI value can be suppressed.
[0011]
According to a second aspect of the present invention, in the configuration of the first aspect, the thickness of the wall portion is increased at a root portion which is a base end portion of each of the vibrating arms.
According to the configuration of the second invention, the thickness of the wall portion is increased particularly at the base portion, which is the base end portion of each vibrating arm, so that the portion where stress is concentrated most has a particularly tough structure.
[0012]
According to a third aspect of the present invention, in the configuration of the second aspect, the groove provided in each of the vibrating arms is extended in the length direction toward the base and reaches the vibrating arm side end of the base. The thickness of the wall is increased in the region of the root and the base.
According to the configuration of the third aspect, the groove is extended until it reaches the base. This groove is a region where a drive electrode is formed, and a drive electrode can be formed in a base region where a drive electrode has not been formed in the past. It is possible to efficiently supply the energy for vibration to the region where the distortion is large while utilizing.
[0013]
According to a fourth aspect of the present invention, in the configuration of the third aspect, the outer shape of each of the groove portions is formed such that an end thereof is inward in the region of the base portion and gradually widens toward an end of the groove portion. It is characterized by having been done.
According to the configuration of the fourth aspect, the outer shape of each of the groove portions is formed such that an end portion thereof is directed inward in the region of the base portion, thereby forming a vibration region corresponding to a strain distribution in the base portion. it can. Furthermore, since the outer shape of each groove is gradually widened toward the end of the groove, such a region is positively used in response to a large strain that spreads in a planar manner at the base. Can be formed to vibrate.
[0014]
According to a fifth aspect of the present invention, there is provided a piezoelectric device in which a piezoelectric vibrating reed is housed in a case or a package, wherein the piezoelectric vibrating reed is entirely formed of a piezoelectric material. A plurality of vibrating arms extending in parallel from the base portion, a groove portion extending in the length direction is formed in each vibrating arm, corresponding to the region where distortion during bending vibration of the plurality of vibrating arms increases. This is achieved by a piezoelectric device in which the groove is adapted to increase the wall thickness of the wall provided on both sides of the groove bottom.
According to the configuration of the fifth aspect, with respect to the piezoelectric vibrating reed accommodated in the case or the package, the grooves are formed on both sides of the groove bottom corresponding to the region where the distortion increases when the plurality of vibrating arms flex and vibrate. The wall thickness of the provided wall portion is increased. For this reason, not only at the time of bending vibration, but also when an external impact is applied, the region where stress is concentrated is structurally strengthened, and the impact resistance of the piezoelectric device is improved.
[0015]
Further, according to a sixth aspect of the present invention, there is provided a mobile phone device using a piezoelectric device in which a piezoelectric vibrating reed is housed in a package, wherein the piezoelectric vibrating reed is entirely formed of a piezoelectric material, A base and a plurality of vibrating arms extending in parallel from the base are provided, and a groove extending in the length direction is formed in each vibrating arm, and in a region where distortion during bending vibration of the plurality of vibrating arms increases. Correspondingly, the present invention is achieved by a mobile phone device in which the groove portion is configured to obtain a clock signal for control by a piezoelectric device configured to increase a wall thickness of a wall portion provided on both sides of the groove bottom portion. You.
[0016]
Still further, according to a seventh aspect of the present invention, there is provided an electronic apparatus using a piezoelectric device in which a piezoelectric vibrating piece is housed in a package, wherein the piezoelectric vibrating piece is entirely formed of a piezoelectric material, A base and a plurality of vibrating arms extending in parallel from the base are provided, and a groove extending in the length direction is formed in each vibrating arm, and in a region where distortion during bending vibration of the plurality of vibrating arms increases. Correspondingly, the present invention is achieved by an electronic device in which the groove portion is configured to obtain a control clock signal by a piezoelectric device configured to increase the wall thickness of a wall portion provided on both sides of the groove bottom portion. .
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
1 and 2 show an embodiment of the piezoelectric device of the present invention. FIG. 1 is a schematic plan view thereof, and FIG. 2 is a schematic sectional view taken along line BB of FIG.
FIGS. 1 and 2 show an example in which the piezoelectric device 30 is configured as a crystal resonator. In the piezoelectric device 30, a piezoelectric vibrating piece 32 is housed in a package 36. The package 36 is formed, for example, by laminating a plurality of substrates formed by molding ceramic green sheets of aluminum oxide as an insulating material, and then sintering. Each of the plurality of substrates is formed with a predetermined hole inside thereof so that when stacked, a predetermined internal space S2 is formed inside when stacked.
This internal space S2 is a housing space for housing the piezoelectric vibrating reed.
That is, as shown in FIG. 2, in this embodiment, the package 36 is formed by, for example, stacking the first laminated substrate 52 and the second laminated substrate 53 from below.
[0018]
An electrode formed by nickel plating and gold plating on a tungsten metallization, for example, is provided on the first laminated substrate 52 which is exposed to the internal space S2 and forms an inner bottom portion near the left end in the drawing in the internal space S2 of the package 36. Parts 31, 31 are provided.
The electrode portions 31 are connected to the outside and supply a drive voltage. A conductive adhesive 43, 43 is applied on each of the electrode portions 31, 31, and a base 51 of the piezoelectric vibrating reed 32 is placed on the conductive adhesive 43, 43, and the conductive adhesive 43 , 43 are cured. In addition, as the conductive adhesives 43, 43, those obtained by adding conductive particles such as silver fine particles to a synthetic resin agent as an adhesive component exhibiting a bonding force can be used. Or polyimide-based conductive adhesive or the like can be used.
Note that the base 51 may be formed with a notch or a recess such as the notches 5a and 5b described in FIG.
[0019]
A lid 39 is joined to the open upper end of the package 36 by using a brazing material 33 to be sealed. The lid body 39 is preferably sealed and fixed to the package 36, and then externally irradiates a laser beam L2 to a metal coating portion (not shown) of the piezoelectric vibrating reed 32 as shown in FIG. In order to adjust the frequency by the reduction method, it is formed of a material that transmits light, particularly, a thin glass plate.
As a glass material suitable for the lid 39, for example, borosilicate glass is used as a thin glass manufactured by a down-draw method.
[0020]
The piezoelectric vibrating reed 32 is formed by etching quartz, and in the case of the present embodiment, the piezoelectric vibrating reed 32 is formed in a small size and is particularly shown in an enlarged manner in FIG. It is shaped. FIG. 4 is a sectional view taken along the line CC of FIG.
In FIG. 3, the piezoelectric vibrating reed 32 is formed by wet etching a crystal wafer cut out of a single crystal of crystal so that the X axis is the electric axis, the Y ′ axis is the mechanical axis, and the Z ′ axis is the optical axis. I have. The piezoelectric vibrating reed 32 includes a base 51 fixed to the package 36 side, and a pair of vibrating arms 34 and 35 which are bifurcated and extend in parallel with the base 51 as a base end. A so-called tuning-fork type piezoelectric vibrating reed having a whole shape like a tuning fork is used.
[0021]
As shown in FIG. 3, a groove 56 and a groove 57 extending in the length direction are provided on the front surface and the back surface of each of the vibrating arms 34 and 35 of the piezoelectric vibrating piece 32.
The vibrating arm 34 is provided with grooves 56, 56 on its front surface and back surface, respectively, and the vibrating arm 35 is provided with grooves 57, 57 on its front surface and back surface, respectively. I have. These grooves can be formed, for example, by etching the quartz wafer to form the outer shape of the piezoelectric vibrating reed 32 and then half-etching the vibrating arm.
[0022]
As shown in FIG. 4, the vibrating arm 34 has a portion 21 that forms the bottom of the groove, and walls that stand on both sides of the portion 21. The structure of the vibrating arm 34 is vertically symmetrical with respect to the center in the thickness direction, as shown in FIG. For this reason, the wall portions 22 and 22 are formed on the upper side and similarly on the lower side with respect to the portion 21 located at the center in the thickness direction. The vibrating arm 35 has the same structure as the vibrating arm 34, and has wall portions 23, 23 formed on the upper side and similarly formed on the lower side with respect to the portion 21 located at the center in the thickness direction. .
[0023]
Further, in FIG. 3, extraction electrodes 58 and 59 are formed near both ends in the width direction of the base 51 of the piezoelectric vibrating reed 32. The extraction electrodes 58 and 59 are similarly formed on the back surface of the base 51 of the piezoelectric vibrating reed 32.
These lead-out electrodes 58 and 59 are portions connected to the package-side electrode portions 31 and 31 shown in FIG. 1 by the conductive adhesives 43 and 43 as described above. The extraction electrodes 58 and 59 are connected to excitation electrodes 63 and 64 (illustrated in FIG. 4 only), which are driving electrodes provided in the grooves 56 and 57 of the respective vibrating arms 34 and 35.
[0024]
That is, as shown in FIG. 4, electrodes are formed in the grooves 56 and 57 of the respective vibrating arms 34 and 35. Specifically, the excitation electrodes 63, 63 are formed in the grooves 56, 56 of the vibrating arm 34, and the excitation electrodes 64, 64 that are paired with the excitation electrodes 63, 63 are formed on both side surfaces of the vibrating arm 34. electrode). On the other hand, excitation electrodes 64, 64 are formed in the grooves 57, 57 of the vibrating arm 35, and excitation electrodes 63, 63, which are paired with the excitation electrodes 64, 64, are formed on both side surfaces of the vibrating arm 35 (side electrodes). Accordingly, the distance between the electrode formed in the groove and the side electrode that forms a pair is short enough to separate the wall of the groove, so that an electric field can be efficiently formed inside the piezoelectric material.
Here, the structure of these electrodes is the same as the main surface of each of the vibrating arms 34 and 35, that is, the upper surface and the lower surface in FIG. The excitation electrodes 63 and 64 on the upper surface in FIG. 4 are front electrodes, and the excitation electrodes 63 and 64 on the lower surface are back electrodes.
[0025]
Next, the characteristic structure of the grooves 56 and 57 of the present embodiment will be described in detail.
FIG. 5 simulates a distribution state of a region where distortion occurs in the piezoelectric vibrating piece 32 when the vibrating arms 34 and 35 bend and vibrate so that their tips 34a and 35a approach and separate as indicated by arrows. The regions are shown in the order of the larger distortions in the order of reference symbols a, b, and c. That is, the region a has the largest distortion, and the region c has the smallest distortion.
According to FIG. 5, regarding the vibrating arms 34 and 35, the area a and the area b are extended from the position of the base R1 to the ends 34a and 35a over the range of L1. Further, in addition to the range of L1, the a region and the b region are also distributed at the end of the base 51 on the side of the vibrating arm. When this range is included, the range of L2 is a region with large distortion.
[0026]
Therefore, as shown in FIG. 3, in this embodiment, the thicknesses of the walls 22, 22, 23, 23 of the grooves 56, 57 of the vibrating arms 34, 35 are set to be thicker than other portions. It is composed. Moreover, preferably, the thickness of these wall portions is gradually increased toward the root portions R1 of the vibrating arms 34 and 35, so that the distribution mode of the strain distribution region in FIG. Have been.
[0027]
For this reason, not only at the time of bending vibration of the vibrating arms 34 and 35, but also at the time of external impact, a region where stress is concentrated is structurally strengthened, so that impact resistance is improved. Further, even if each vibrating arm and the groove portion are lengthened and the vibrating arm is largely shaken during bending vibration, there is no fear of breakage. Further, for example, in order to vibrate in the same manner as in the related art, only a small driving voltage is required, so that a piezoelectric vibrating reed having a low CI value can be realized.
In particular, at the root portion R1, which is the base end portion of each of the vibrating arms 34, 35, the thickness of the above-described wall portions 22, 22, 23, 23 is increased, so that a portion where stress is concentrated most has a particularly tough structure.
[0028]
Further, as shown in FIG. 3, the grooves 56, 57 provided in the respective vibrating arms 34, 35 are extended in the length direction toward the base 51, and include the above-described range of L2. 51 is extended to a vibrating arm side end (hereinafter, referred to as “end region”). For this reason, the driving electrode can be formed in the region of the base 51 where the driving electrode has not been formed conventionally, and the region where the distortion is large while using the region not conventionally used is used. Energy for vibration can be efficiently supplied to the motor.
[0029]
The outer shapes of the grooves 56 and 57 are such that the ends 26 and 27 are inwardly directed in the region of the base 51.
That is, as shown in FIG. 5, in the end region of the base portion 51, a region having a large distortion is distributed in a curved shape, and the end portion 26, 27 are formed inward. This makes it possible to utilize a region having a large distortion as much as possible without waste.
Further, the outer shape of each of the grooves 56 and 57 is gradually widened toward the ends 26 and 27 of the grooves by the enlarged diameter portions 24 and 25. For this reason, in the end region of the base portion 51, a portion that vibrates by positively utilizing such a region can be formed corresponding to a region having a large strain that spreads in a plane.
[0030]
FIG. 6 is a view showing a state in which the piezoelectric vibrating piece 32 adopting the groove structure of the piezoelectric vibrating piece 32 is dropped from a position having a height of 1.5 m in the embodiment of the present invention, and the piezoelectric vibrating piece 32 7 is a graph showing the results of measuring the force applied to the root of each vibrating arm.
As shown, the force applied to the joint is reduced by about 40% as compared with the conventional piezoelectric device.
[0031]
FIG. 7 is a diagram illustrating a schematic configuration of a digital mobile phone device as an example of an electronic apparatus using the piezoelectric device according to the embodiment of the present invention.
In the figure, a microphone 308 for receiving the voice of the sender and a speaker 309 for outputting the received content as a voice output are provided. Controller (CPU) 301.
The controller 301 is an information input / output unit 302 including an LCD as an image display unit and operation keys for inputting information, and a memory as an information storage unit including a RAM and a ROM, in addition to modulation and demodulation of transmission / reception signals. Control 303 is performed. For this reason, the piezoelectric device 30 is attached to the controller 301, and its output frequency is used as a clock signal suitable for the control content by a predetermined frequency dividing circuit (not shown) or the like built in the controller 301. Has been. The piezoelectric device 30 attached to the controller 301 is not limited to the piezoelectric device 30 alone, but may be an oscillator combining the piezoelectric device 30 with a predetermined frequency dividing circuit or the like.
[0032]
The controller 301 is further connected to a temperature-compensated crystal oscillator (TCXO) 305, and the temperature-compensated crystal oscillator 305 is connected to a transmitting unit 307 and a receiving unit 306. Thus, even if the basic clock from the controller 301 fluctuates when the environmental temperature changes, it is corrected by the temperature-compensated crystal oscillator 305 and provided to the transmission unit 307 and the reception unit 306.
As described above, by using the piezoelectric device 30 according to the above-described embodiment in an electronic device such as the digital mobile phone device 300, the digital mobile phone device 300 that can suppress the CI value and has high reliability can be provided. Obtainable.
[0033]
The invention is not limited to the embodiments described above. Each configuration of each embodiment can be appropriately combined or omitted, and can be combined with another configuration not shown.
Further, the present invention can be applied to all piezoelectric devices irrespective of the names of a crystal oscillator, a crystal oscillator, and the like as long as the piezoelectric vibrating reed is housed in a package.
Furthermore, in the above-described embodiment, a box-shaped package using a quartz material is used for the package. However, the present invention is not limited to such a configuration, and a piezoelectric vibrating reed is accommodated in a metal or ceramic cylindrical case. For example, the present invention can be applied to a device with any package or case.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing an embodiment of a piezoelectric device of the present invention.
FIG. 2 is a schematic sectional view taken along the line BB of FIG. 1;
FIG. 3 is an enlarged schematic plan view of the piezoelectric vibrating reed of FIG. 1;
FIG. 4 is a sectional view taken along the line CC of FIG. 3;
FIG. 5 is a diagram showing a distribution of a distortion region in bending vibration of the piezoelectric vibrating reed of FIG. 1;
FIG. 6 is a graph comparing impact resistance of a conventional piezoelectric device and a piezoelectric device according to an embodiment of the present invention.
FIG. 7 is a diagram showing a schematic configuration of a digital mobile phone device as an example of an electronic apparatus using a piezoelectric device according to an embodiment of the present invention.
FIG. 8 is a schematic plan view showing a conventional piezoelectric device.
FIG. 9 is a sectional view taken along line AA of FIG. 8;
FIG. 10 is a view showing a distribution of a distortion region in bending vibration of the piezoelectric vibrating reed of FIG. 8;
[Explanation of symbols]
Reference numeral 30: piezoelectric device, 32: piezoelectric vibrating piece, 34, 35: vibrating arm, 56, 57: groove, 63, 64: excitation electrode (drive electrode)

Claims (7)

A piezoelectric vibrating reed formed entirely of a piezoelectric material, including a base and a plurality of vibrating arms extending in parallel from the base, and a groove extending in the length direction is formed on each vibrating arm,
The groove portion is configured to increase a wall thickness of a wall portion provided on both sides of a groove bottom portion corresponding to a region where distortion during bending vibration of the plurality of vibrating arms increases. , Piezoelectric vibrating reed. The piezoelectric vibrating reed according to claim 1, wherein a thickness of the wall portion is increased at a root portion that is a base end portion of each of the vibrating arms. The groove provided in each of the vibrating arms is extended in the length direction toward the base, so as to reach the vibrating arm side end of the base, in the region of the root and the base, The piezoelectric vibrating reed according to claim 2, wherein a thickness of the wall portion is increased. The external shape of each said groove part is formed so that the edge part may become inward in the area | region of the said base part, and may become gradually wide toward the edge part of a groove part, The claim 4 characterized by the above-mentioned. Piezoelectric vibrating reed. A piezoelectric device containing a piezoelectric vibrating reed in a case or a package,
The piezoelectric vibrating reed,
The whole is formed of a piezoelectric material, and includes a base and a plurality of vibrating arms extending in parallel from the base, and a groove extending in the length direction is formed in each vibrating arm,
The groove portion is configured to increase a wall thickness of a wall portion provided on both sides of a groove bottom portion corresponding to a region where distortion during bending vibration of the plurality of vibrating arms increases. , Piezoelectric devices. A mobile phone device using a piezoelectric device containing a piezoelectric vibrating reed in a package,
The piezoelectric vibrating reed,
The whole is formed of a piezoelectric material, and includes a base and a plurality of vibrating arms extending in parallel from the base, and a groove extending in the length direction is formed in each vibrating arm,
The groove is controlled by a piezoelectric device in which the wall thickness of the wall provided on both sides of the groove bottom is increased in accordance with an area where distortion during bending vibration of the plurality of vibrating arms is increased. A mobile phone device for obtaining a clock signal for use. An electronic device using a piezoelectric device containing a piezoelectric vibrating piece in a package,
The piezoelectric vibrating reed,
The whole is formed of a piezoelectric material, and includes a base and a plurality of vibrating arms extending in parallel from the base, and a groove extending in the length direction is formed in each vibrating arm,
The groove is controlled by a piezoelectric device in which the wall thickness of the wall provided on both sides of the groove bottom is increased in accordance with an area where distortion during bending vibration of the plurality of vibrating arms is increased. An electronic device characterized in that a clock signal for use is obtained.

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