JP6348728B2 - Piezoelectric vibrating piece, piezoelectric vibrator, oscillator, electronic device, and radio timepiece - Google Patents

Description

  The present invention relates to a piezoelectric vibrating piece, a piezoelectric vibrator, an oscillator, an electronic device, and a radio timepiece.

  A tuning fork type crystal resonator in which a plurality of grooves are formed in the vibrating arm is known for the purpose of reducing the equivalent resistance value, that is, the CI (Crystal Impedance) value, while suppressing the strength reduction of the vibrating arm. (For example, Patent Document 1).

JP 2006-60727 A

  By the way, the vibration mode of the vibrating arm includes a secondary bending mode (harmonic mode) in addition to the fundamental wave mode. In order to obtain stable frequency characteristics, it is preferable to vibrate the vibrating arm portion in the fundamental wave mode.

  However, for example, in the configuration described in Patent Document 1, the degree of reduction in the CI value (hereinafter referred to as R2 value) in the secondary bending mode decreases the CI value (hereinafter referred to as R1 value) in the fundamental wave mode. Since it is larger than the degree, there is a problem that the vibrating arm portion is easily vibrated in the secondary bending mode.

  One aspect of the present invention has been made in view of the above problems, and a piezoelectric vibrating piece capable of suppressing vibration in a secondary bending mode while suppressing a decrease in strength of a vibrating arm, and An object is to provide a piezoelectric vibrator. Another object of one embodiment of the present invention is to provide an oscillator, an electronic device, and a radio timepiece having such a piezoelectric vibrator and having excellent reliability.

  One aspect of the piezoelectric vibrating piece of the present invention includes a base and a pair of vibrating arms connected to the base and arranged side by side in the width direction. A plurality of groove portions extending in the length direction of the vibrating arm portion along the width direction and a connecting groove portion connecting the plurality of adjacent groove portions are formed, and the length is between the adjacent groove portions. A wall portion is formed along the direction, and at least a part of the wall portion is provided closer to the distal end side of the vibrating arm portion than the center in the length direction of the groove portion, and the connecting groove portion is adjacent to the distal end side. The matching groove portions are connected to each other.

  The connecting groove portion may be formed in the vicinity of a portion that becomes the vibration node portion on the distal end side of the vibrating arm portion when the vibrating arm portion vibrates in the secondary bending mode.

  The connecting groove portion may be formed in a portion that becomes a vibration node portion on the distal end side of the vibrating arm portion when the vibrating arm portion vibrates in a secondary bending mode.

  The connecting groove portion may be configured to connect the adjacent groove portions at the end portion on the distal end side.

  The said wall part is good also as a structure divided | segmented into the 1st wall part by the side of the said base, and the 2nd wall part by the side of the said front end by the said connection groove part.

  The connecting groove portions provided in the pair of vibrating arm portions pass through the center in the width direction between the pair of vibrating arm portions and are parallel to the center line parallel to the length direction. It is good also as a structure provided symmetrically.

  One aspect of the piezoelectric vibrator of the present invention includes a base member and a lid member that is overlapped and joined to the base member and that forms a hermetically sealed cavity with the base member. And the above-described piezoelectric vibrating piece mounted on the mounting surface of the base member and accommodated in the cavity.

  One aspect of the oscillator according to the present invention includes the above-described piezoelectric vibrator, and the piezoelectric vibrator is electrically connected to an integrated circuit as an oscillator.

  One aspect of the electronic apparatus according to the present invention includes the above-described piezoelectric vibrator, and the piezoelectric vibrator is electrically connected to a timer unit.

  One aspect of the radio-controlled timepiece of the present invention includes the above-described piezoelectric vibrator, and the piezoelectric vibrator is electrically connected to a filter portion.

  According to one aspect of the present invention, there are provided a piezoelectric vibrating piece and a piezoelectric vibrator capable of suppressing a vibration in a secondary bending mode while suppressing a decrease in strength of a vibrating arm. Moreover, according to one aspect of the present invention, an oscillator, an electronic device, and a radio timepiece that are provided with such a piezoelectric vibrator and have excellent reliability are provided.

FIG. 3 is an exploded perspective view showing the piezoelectric vibrator of the first embodiment. It is sectional drawing which shows the piezoelectric vibrator of 1st Embodiment. It is a top view which shows the piezoelectric vibrating piece of 1st Embodiment. It is a figure which shows the piezoelectric vibrating piece of 1st Embodiment, Comprising: It is IV-IV sectional drawing in FIG. It is a figure which shows the piezoelectric vibrating piece of 1st Embodiment, Comprising: It is VV sectional drawing in FIG. It is a top view which shows the piezoelectric vibrating piece of 2nd Embodiment. It is a top view which shows the piezoelectric vibrating piece of 3rd Embodiment. It is a figure which shows an example of embodiment of an oscillator. It is a figure which shows an example of embodiment of an electronic device. It is a figure which shows an example of embodiment of a radio timepiece. It is a top view which shows the piezoelectric vibrating piece of a reference example. It is behavior explanatory drawing when the piezoelectric vibrating piece of a reference example vibrates in fundamental wave mode. It is behavior explanatory drawing when the piezoelectric vibrating piece of a reference example vibrates in the secondary bending mode. It is a graph which shows the change of R1 value of the piezoelectric vibrating piece of a reference example, and R2 value.

Hereinafter, a piezoelectric vibrating piece and a piezoelectric vibrator according to an embodiment of the present invention will be described with reference to the drawings.
The scope of the present invention is not limited to the following embodiment, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in the following drawings, in order to make each structure easy to understand, the actual structure may be different from the scale, number, or the like in each structure.

(First embodiment)
[Piezoelectric vibrator]
1 and 2 are diagrams showing the piezoelectric vibrator 1 of the present embodiment. FIG. 1 is an exploded perspective view. FIG. 2 is a cross-sectional view. 3 to 5 are views showing the piezoelectric vibrating piece 100 of the present embodiment. FIG. 3 is a plan view. 4 is a cross-sectional view taken along the line IV-IV in FIG. 5 is a cross-sectional view taken along the line VV in FIG.

  In the following description, the XYZ axes are set, and the positional relationship of each member will be described with reference to this XYZ coordinate system. At this time, the thickness direction of the piezoelectric vibrator 1 (see FIG. 1) is the Z-axis direction, the longitudinal direction of the piezoelectric vibrator 1 is the Y-axis direction, and the short direction of the piezoelectric vibrator 1 is the X-axis direction.

  As shown in FIG. 1, the piezoelectric vibrator 1 of the present embodiment is a so-called ceramic package type surface mount vibrator having a substantially rectangular parallelepiped shape. The piezoelectric vibrator 1 includes a package 2 having a cavity C1 hermetically sealed and a piezoelectric vibrating piece 100 accommodated in the cavity C1.

  As shown in FIG. 1, the package 2 includes a package body (base member) 3 and a sealing plate (lid member) 4. The package body 3 is a member having a bottomed recess 3a. The recess 3a includes an inner side surface 52a of a seal ring 52 to be described later, an inner side surface of a through hole 51a formed on the second base substrate 51 to be described later, and an upper surface 50a of the first base substrate 50 to be described later. Yes.

  The sealing plate 4 closes the opening of the recess 3 a of the package body 3 and is joined to the package body 3. The cavity C <b> 1 is an internal space corresponding to the inside of the recess 3 a of the package body 3, and is partitioned from the outside of the package 2 by the package body 3 and the sealing plate 4.

  The package body 3 includes a first base substrate 50, a second base substrate 51 disposed on the first base substrate 50, and a seal ring 52 disposed on the second base substrate 51.

  Each of the first base substrate 50 and the second base substrate 51 is a plate-like member having a substantially rectangular outer shape in plan view (XY plane view). The second base substrate 51 has substantially the same outer dimensions as the first base substrate 50 in plan view (XY plane view).

  The first base substrate 50 and the second base substrate 51 are each made of ceramics. The formation material of the first base substrate 50 and the second base substrate 51 may be, for example, high temperature co-fired ceramic (HTCC) mainly composed of alumina, or low temperature such as glass ceramics. It may be fired ceramics (LTCC: Low Temperature Co-Fired Ceramic).

In the first base substrate 50, a part of the upper surface 50 a on the second base substrate 51 side (+ Z side) corresponds to the bottom surface of the recess 3 a of the package body 3.
The second base substrate 51 is overlaid on the first base substrate 50 and is coupled to the first base substrate 50 by sintering or the like. That is, the second base substrate 51 is integrated with the first base substrate 50.

  As shown in FIGS. 1 and 2, a through hole 51 a is formed in the second base substrate 51. The inner side surface of the through hole 51 a constitutes a part of the side wall of the recess 3 a of the package body 3. A mounting portion 55 is provided on the inner surface on one side (−X side) in the short direction of the through hole 51a so as to protrude from the through hole 51a. A mounting portion 56 is provided on the inner surface of the other side (+ X side) of the through hole 51a in the short side direction so as to protrude from the through hole 51a. The mounting part 55 and the mounting part 56 are provided to face each other. The plan view (XY plane view) shape of the through-hole 51a is a shape obtained by removing the plane view (XY plane view) shapes of the mounting portions 55 and 56 from a rectangle.

  The surfaces on the seal ring 52 side (+ Z side) of the mounting portions 55 and 56 are mounting surfaces 55a and 56a on which the piezoelectric vibrating piece 100 is mounted. An electrode pad 53 is provided on the mounting surface 55a. An electrode pad 54 is provided on the mounting surface 56a. The planar view (XY plane view) shape of the mounting portions 55 and 56 is, for example, a rectangular shape in the present embodiment. As shown in FIG. 2, the mounting portions 55 and 56 are in contact with the piezoelectric vibrating reed 100 through the electrode pads 53 and 54.

The electrode pad 53 and the electrode pad 54 are a pair of terminals that are electrically connected to the piezoelectric vibrating piece 100. The electrode pad 53 and the electrode pad 54 are, for example, bump electrodes.
As will be described in detail later, the piezoelectric vibrating piece 100 is provided with a mount portion 17 and a mount portion 18 for mounting on a substrate. The electrode pad 53 is electrically connected to a mount electrode (not shown) formed on the mount portion 17 of the piezoelectric vibrating piece 100, and the electrode pad 54 is connected to a mount electrode (not shown) formed on the mount portion 18 of the piezoelectric vibrating piece 100. Electrically connected.

  As shown in FIG. 1, the seal ring 52 is a rectangular frame member in plan view (XY plane view), and constitutes a part of the side wall of the recess 3 a of the package body 3. The outer dimension of the seal ring 52 in plan view (XY view) is slightly smaller than that of the second base substrate 51. The seal ring 52 is bonded to the surface of the second base substrate 51 on the seal ring 52 side (+ Z side) (hereinafter, the upper surface of the second base substrate 51) by baking using a brazing material such as silver brazing or a solder material. Has been. The seal ring 52 may be bonded to the upper surface of the second base substrate 51 by welding or the like to the metal bonding layer formed on the upper surface of the second base substrate 51. The metal bonding layer may be formed using at least one of an electrolytic plating method, an electroless plating method, a vapor deposition method, and a sputtering method.

The seal ring 52 is a conductive member and includes, for example, a nickel-based alloy. This nickel-based alloy may contain one or more of Kovar, Elinvar, Invar, and 42-alloy. The material for forming the seal ring 52 may be selected from materials having a thermal expansion coefficient close to that of the first base substrate 50 and the second base substrate 51. For example, when alumina having a thermal expansion coefficient of 6.8 × 10 ⁻⁶ / ° C. is used as a material for forming the first base substrate 50 and the second base substrate 51, the material for forming the seal ring 52 is a coefficient of thermal expansion. May be Kovar of 5.2 × 10 ⁻⁶ / ° C., or 42-alloy having a thermal expansion coefficient of 4.5 to 6.5 × 10 ⁻⁶ / ° C.

  The inner shape of the seal ring 52 is overlapped with the through hole 51a in a plan view (XY view) except for places where the mounting portions 55 and 56 are formed.

  As shown in FIG. 2, the sealing plate 4 is stacked on the seal ring 52 and closes the opening of the seal ring 52 (opening of the recess 3 a). The cavity C1 described above is a space surrounded by the first base substrate 50, the second base substrate 51, the seal ring 52, and the sealing plate 4. That is, the piezoelectric vibrating piece 100 is accommodated inside the seal ring 52 in a plan view (XY plane view).

  The sealing plate 4 is a conductive substrate and is joined to the seal ring 52. The seal ring 52 is joined to the sealing plate 4 by welding such as seam welding, laser welding, or ultrasonic welding by bringing a roller electrode into contact with each other. When welding the sealing plate 4 and the seal ring 52, nickel, gold or the like is bonded to one or both of the lower surface (the surface on the −Z side) of the sealing plate 4 and the upper surface of the seal ring 52 (the surface on the + Z side). When the layer is provided, the reliability of joining by welding is improved, and for example, it becomes easy to ensure the airtightness of the cavity C1.

An external electrode 57 and an external electrode 58 are provided on the lower (−Z side) surface of the first base substrate 50.
The external electrode 57 and the external electrode 58 are terminals that receive power from a device external to the piezoelectric vibrator 1, for example, a device on which the piezoelectric vibrator 1 is mounted.

  The package body 3 includes a first wiring (not shown) that electrically connects the electrode pad 53 and the external electrode 57, and a second wiring (not shown) that electrically connects the electrode pad 54 and the external electrode 58. )). That is, the potential applied to the external electrode 57 is applied to the mount electrode formed on the mount portion 17 of the piezoelectric vibrating piece 100 via the first wiring and the electrode pad 53. The potential applied to the external electrode 58 is applied to the mount electrode formed on the mount portion 18 of the piezoelectric vibrating piece 100 via the second wiring and the electrode pad 54. The piezoelectric vibrating piece 100 vibrates by electric power supplied to each mount electrode.

  The first wiring includes, for example, a first through electrode that penetrates the first base substrate 50 in the thickness direction (Z-axis direction) and is electrically connected to the external electrode 57, and a second base substrate 51 in the thickness direction (Z-axis direction). ) And a second through electrode that is electrically connected to the electrode pad 53, and is provided between the first base substrate 50 and the second base substrate 51, and electrically connects the first through electrode and the second through electrode. Connection wiring. The second wiring that electrically connects the electrode pad 54 and the external electrode 58 has the same configuration as the first wiring. The configuration of the first wiring and the second wiring can be changed as appropriate.

[Piezoelectric vibrating piece]
Next, the piezoelectric vibrating piece 100 of this embodiment will be described.
The piezoelectric vibrating piece 100 is a plate-like component in which an accessory such as a conductive film pattern that functions as an electrode or a wiring is formed on a piezoelectric body such as quartz, lithium tantalate, or lithium niobate. The piezoelectric vibrating piece 100 of the present embodiment is a so-called side arm type piezoelectric vibrating piece.
In the present embodiment, a case where the piezoelectric body of the piezoelectric vibrating piece 100 is a crystal will be described.

  As shown in FIG. 3, the piezoelectric vibrating piece 100 includes a base portion 10, a pair of vibrating arm portions 21 and 22 that are connected to the base portion 10 and arranged in the width direction (X-axis direction), and vibrations in the base portion 10. Two support arm parts 15 and 16 connected to both sides in the width direction (X-axis direction) of the arm parts 21 and 22 and two mount parts 17 and 18 provided on the support arm parts 15 and 16 are provided. In the present embodiment, the base portion 10, the pair of vibrating arm portions 21 and 22, and the supporting arm portions 15 and 16 are integrally formed, and adjacent portions are continuous without an interface. 3 and 4, in order to indicate the range of each part, the base end or the distal end of each part is indicated by a two-dot chain line. The same applies to FIGS. 6 and 7 described later.

The base portion 10 connects the support arm portions 15 and 16 and the vibrating arm portions 21 and 22.
The planar view (XY plane view) shape of the base 10 is rectangular as shown in FIG.
Support arm portions 15 and 16 are connected to the ends of the vibration arm portions 21 and 22 in the base portion 10 on both sides in the width direction (± X side), respectively. The vibrating arm portions 21 and 22 are connected to one side (+ Y side) in the length direction of the vibrating arm portions 21 and 22 in the base portion 10.

The vibrating arm portions 21 and 22 are respectively connected to the base portion 10 at one end (−Y side) in the length direction. The vibrating arm portion 21 and the vibrating arm portion 22 pass through the center in the width direction (X-axis direction) between the vibrating arm portion 21 and the vibrating arm portion 22, and the length direction (Y-axis) of the vibrating arm portions 21 and 22. Are symmetrical with respect to a center line P21 parallel to (direction).
Since the vibrating arm portion 21 and the vibrating arm portion 22 have the same shape and size, only the vibrating arm portion 21 may be described as a representative in the following description.

  The vibrating arm portion 21 includes a belt-like portion 11 that extends linearly with a substantially uniform width, and a hammer portion 13 having a width (length in the X-axis direction) wider than that of the belt-like portion 11. Similarly, the vibrating arm portion 22 includes a belt-like portion 12 and a hammer portion 14.

  The hammer parts 13 and 14 are arranged along the longitudinal direction (Y-axis direction) of the band-like parts 11 and 12 from the tip (+ Y side) opposite to the side connected to the base part 10 of the band-like parts 11 and 12, respectively. It is formed to extend. The width of the hammer portions 13 and 14 (length in the X-axis direction) is formed larger than the width of the band-shaped portions 11 and 12 (length in the X-axis direction). The hammer portions 13 and 14 are set as free ends that vibrate in the width direction (X-axis direction) with the base portion 10 as a fixed end.

The belt-like portion 11 of the vibrating arm portion 21 extends linearly from the base portion 10 along the longitudinal direction (Y-axis direction) of the piezoelectric vibrator 1.
A groove portion 31a, a groove portion 32a, and a connecting groove portion 35a are formed on the surface (the main surface on the + Z side) 19a of the piezoelectric vibrating piece 100 in the belt-like portion 11. The groove part 31 a and the groove part 32 a are formed side by side in the width direction (X-axis direction) of the vibrating arm part 21. The grooves 31 a and 32 a extend from the end of the vibrating arm 21 on the base 10 side (−Y side) substantially parallel to the length direction (Y-axis direction) of the vibrating arm 21. The depth direction of the groove portions 31 a and 32 a is substantially parallel to the thickness direction (Z-axis direction) of the piezoelectric vibrating piece 100.

  The cross-sectional view (ZX view) shape of the groove portions 31a and 32a is not particularly limited, and may be a rectangular shape, a polygonal shape, or other shapes. In this embodiment, the cross-sectional view (ZX plane view) shape of the groove parts 31a and 32a is, for example, a pentagonal shape as shown in FIG. In the present embodiment, as will be described later, since the groove portions 31a and 32a are formed by etching, the inner walls of the groove portions 31a and 32a have a shape corresponding to the crystal plane.

  As shown in FIG. 3, the connecting groove 35a connects the groove 31a and the groove 32a. That is, the inside of the groove portion 31a and the inside of the groove portion 32a communicate with each other through the connecting groove portion 35a. The connecting groove 35a is formed on the tip side (+ Y side) from the center line P11 that passes through the center in the length direction (Y-axis direction) of the grooves 31a and 32a and is parallel to the width direction (X-axis direction). ing. In other words, the connecting groove part 35a connects the adjacent groove part 31a and the groove part 32a on the front end side (+ Y side) of the groove parts 31a and 32a in the length direction. In the present embodiment, the connecting groove 35a is formed at or near a portion that becomes a vibration node on the distal end side (+ Y side) when the vibrating arm portion 21 vibrates in the secondary bending mode.

  In the present specification, the connecting groove portion 35a is provided at a portion that becomes a vibration node portion on the distal end side (+ Y side) of the vibrating arm portion 21 in the secondary bending mode. This means that the wall portion is not provided in the portion, and it is not necessary that the center position in the length direction (Y-axis direction) of the connecting groove portion 35a coincides with the position of the vibration node portion on the distal end side. That is, the connecting groove 35a is provided in a portion that becomes the vibration node portion on the tip side (+ Y side) of the vibrating arm portion 21 in the secondary bending mode. The connection groove portion 35a becomes the vibration node portion on the tip side. As long as it contains a part.

  Further, in this specification, the connecting groove 35a is provided in the “near” portion of the vibration node portion on the tip side (+ Y side) of the vibrating arm portion 21 in the secondary bending mode. This means that the positional deviation between the groove 35 a and the vibration node is about 1/6 or less of the length of the vibration arm 21. Further, the positional deviation between the coupling groove 35a and the vibration node means that the distance from the vibration node to the end of the connection groove 35a closest to the vibration node when the coupling groove 35a is not formed in the vibration node. Shall mean.

  As shown in FIGS. 4 and 5, on the back surface (the main surface on the −Z side) 19b of the piezoelectric vibrating piece 100 in the band-shaped portion 11, the groove portion 31b, the groove portion 32b, and the connecting groove portion 35b are formed in the same manner as the front surface 19a. Is formed. In the present embodiment, the groove 31a and the groove 31b are formed so as to overlap in a plan view (XY plane view). The groove part 32a and the groove part 32b are formed so as to overlap in plan view. The connecting groove 35a and the connecting groove 35b are formed so as to overlap in plan view.

  As shown in FIGS. 3 to 5, similarly to the vibrating arm portion 21, a groove portion 33 a, a groove portion 34 a, and a connecting groove portion 36 a are formed on the surface 19 a of the band-like portion 12 of the vibrating arm portion 22. On the back surface 19b of the belt-like portion 12, a groove portion 33b, a groove portion 34b, and a connecting groove portion 36b are formed.

  In addition, since each groove part and each connection groove part are the respectively same structures, only the groove part 31a and the connection groove part 35a may be demonstrated as a representative.

  As shown in FIG. 3, the connecting groove portions 35a and 35b in the vibrating arm portion 21 and the connecting groove portions 36a and 36b in the vibrating arm portion 22 are provided symmetrically with respect to the center line P21.

  In this specification, the term “line symmetry” does not mean only the case of strictly line symmetry, but the range in which the dimensional ratio is about 0.9 or more and 1.1 or less, and the positional deviation. Is included up to a range of about 5% or less of the width of the object. In addition, a slight difference in the shape of the inner wall determined by the crystal plane when the crystal is etched is also included.

As shown in FIGS. 3 and 4, a first wall portion 41a and a second wall portion 42a that separate the groove portion 31a and the groove portion 32a are formed between the adjacent groove portions 31a and 32a.
The first wall portion 41a is provided to extend from the end portion of the groove portions 31a, 32a on the base 10 side (−Y side) to the distal end side (+ Y side) in the length direction of the groove portions 31a, 32a. That is, the first wall portion 41a is provided to extend from the base portion 10 to the distal end side (+ Y side) from the center line P11. In other words, a part of the first wall portion 41a is provided on the distal end side (+ Y side) of the vibrating arm portion 21 with respect to the center line P11.

The second wall portion 42a is provided to extend from the end portion (+ Y side) of the groove portions 31a, 32a to the base portion 10 side (−Y side). The entire second wall portion 42a is provided on the tip side (+ Y side) from the center line P11.
The first wall portion 41a and the second wall portion 42a are provided to face each other in the length direction (Y-axis direction) of the vibrating arm portion 21 with the coupling groove portion 35a interposed therebetween. In other words, the wall part formed between the groove part 31a and the groove part 32a is divided | segmented into the 1st wall part 41a and the 2nd wall part 42a by the connection groove part 35a.

  The sectional view (ZX plane view) shape of the first wall portion 41a and the second wall portion 42a is not particularly limited, and may be a rectangular shape, a polygonal shape, or other shapes. In this embodiment, the cross-sectional view (ZX plane view) shape of the 1st wall part 41a and the 2nd wall part 42a is trapezoid shape, as shown in FIG. In this embodiment, as will be described later, since the groove portions 31a and 32a are formed by etching, the side walls of the first wall portion 41a and the second wall portion 42a have shapes corresponding to crystal planes.

Similarly to the above, a first wall portion 41b and a second wall portion 42b that separate the groove portion 31b and the groove portion 32b are formed between the adjacent groove portions 31b and 32b.
Similarly, in the vibrating arm portion 22, a first wall portion 43a and a second wall portion 44a that separate the groove portion 33a and the groove portion 34a are formed between the adjacent groove portions 33a and 34a. A first wall portion 43b and a second wall portion 44b that separate the groove portion 33b and the groove portion 34b are formed between the adjacent groove portions 33b and the groove portion 34b.
The first wall portions 41b, 43a, 43b are the same as the first wall portion 41a. The second wall portions 42b, 44a, 44b are the same as the second wall portion 42a.

  In the present embodiment, the groove portions 31a and 32a and the connecting groove portion 35a are formed by etching. The etching method is not particularly limited, and dry etching may be selected or wet etching may be selected.

  Excitation electrodes (not shown) are formed on the inner surfaces of the front surface 19a, the rear surface 19b, and the grooves 31a, 31b, 32a, and 32b in the vibrating arm portion 21. The same applies to the vibrating arm portion 22.

  The pair of support arm portions 15 and 16 extend from the base portion 10 on both sides in the width direction (X-axis direction) of the vibrating arm portions 21 and 22, and then the length direction (Y-axis direction) of the vibrating arm portions 21 and 22. Are bent and extended toward the distal end side (+ Y side) of the vibrating arm portions 21 and 22.

  Mount portions 17 and 18 are provided on the back surface 19b side (-Z side) of the support arm portions 15 and 16, respectively. The positions where the mount portions 17 and 18 are provided are positions that become nodes of vibration when the support arm portions 15 and 16 vibrate.

  Mount electrodes (not shown) are formed on the mount parts 17 and 18 of the support arm parts 15 and 16, and are connected to excitation electrodes formed on the outer surfaces of the vibrating arm parts 21 and 22 by lead electrodes (not shown). . Then, when a predetermined voltage is applied to each of these electrodes, the pair of vibrating arm portions 21 and 22 approach or separate from each other due to the interaction between the excitation electrodes of the pair of vibrating arm portions 21 and 22. Vibrates at a predetermined resonance frequency (in the X-axis direction).

  According to the present embodiment, since the connecting groove 35a is formed on the front end side (+ Y side) of the groove 31a and the groove 32a, the vibration can be vibrated in the secondary bending mode while suppressing the strength reduction of the vibrating arm. Can be suppressed. Details will be described below.

  11 to 14 are diagrams for explaining the vibration mode of the vibrating arm portion. FIG. 11 is a plan view showing a piezoelectric vibrating piece 2001 of a reference example. FIG. 12 is a behavior explanatory diagram illustrating a case where the piezoelectric vibrating piece 2001 vibrates in the fundamental wave mode. FIG. 13 is a behavior explanatory diagram illustrating a case where the piezoelectric vibrating piece 2001 vibrates in the secondary bending mode. FIG. 14 is a graph showing changes in the R1 value and the R2 value in the piezoelectric vibrating piece 2001.

  As shown in FIG. 11, the tuning-fork type piezoelectric vibrating piece 2001 includes a pair of vibrating arm portions 2010 and 2011 arranged side by side in the width direction, and the longitudinal base ends of the pair of vibrating arm portions 2010 and 2011. It is a thin plate-shaped crystal piece having a base 2020 to be connected. Excitation electrodes 2030 that vibrate the pair of vibrating arm portions 2010 and 2011 are formed on the outer surfaces of the pair of vibrating arm portions 2010 and 2011.

  As shown in FIG. 12, the piezoelectric vibrating reed 2001 is configured such that when a voltage is applied to the excitation electrode 2030 formed on each vibrating arm 2010, the tips of the pair of vibrating arms 2010 and 2011 approach and separate. Oscillate at a predetermined resonance frequency in a predetermined direction. In the following description, a vibration mode that vibrates such that the tips of the pair of vibrating arm portions 2010 and 2011 approach and separate from each other is referred to as a fundamental wave mode.

  As shown in FIG. 13, when the piezoelectric vibrating piece 2001 vibrates in the secondary bending mode, the vibration nodes 2010a and 2011a are formed at the proximal ends of the vibration arms 2010 and 2011, respectively, and the vibration node at the distal end side. 2010b and 2011b are formed, and the displacement amount at the approximate center between the vibration node portions 2010a and 2011a on the proximal end side of these vibration arm portions 2010 and 2011 and the vibration node portions 2010b and 2011b on the distal end side is maximized. Amplitude to.

At this time, when the total length of the vibrating arm portions 2010 and 2011 is L100, the distance SL1 between the base ends of the vibrating arm portions 2010 and 2011 and the vibration node portions 2010b and 2011b on the distal end side is about (3 × L100). / 4 or so. The distance SL2 between the base ends of the vibrating arm portions 2010 and 2011 and the position P100 where the displacement amount of the vibrating arm portions 2010 and 2011 is maximum (hereinafter referred to as the maximum amplitude portion P100) is about L100 / 2. Become.
In such a case, when the vibration mode is changed, the frequency of the piezoelectric vibrating piece 2001 is also changed. For example, in the case of a tuning fork-type piezoelectric vibrating piece 2001, the frequency changes from 32 kHz to 200 kHz. Therefore, it is preferable to vibrate the piezoelectric vibrating piece 2001 in the fundamental wave mode.

  Here, if the groove portion 2040 formed in the vibrating arm portions 2010 and 2011 is formed large, the CI value can be lowered accordingly. In order to form the groove 2040 large, it is conceivable to increase the groove width, deepen the groove depth, or increase the groove length. However, each method has the following problems.

  First, when the groove length TL100 is increased, not only the CI value (R1 value) in the fundamental wave mode but also the CI value (R2 value) in the secondary bending mode is decreased. In addition, the R2 value is much lower than the R1 value.

As shown in FIG. 14, it can be confirmed that the decrease slope of the R2 value is larger than the decrease slope of the R1 value as the value of TL100 / L100 increases.
Here, when the R2 value is smaller than the R1 value, the vibrating arm 2010 vibrates in the secondary bending mode. For example, in the case of the piezoelectric vibrating piece 2001, as shown in FIG. 14, when the value of TL100 / L100 becomes about 0.58, the R2 value becomes smaller than the R1 value, and the vibrating arm portion 2010 vibrates in the secondary bending mode. There was a problem that.

  On the other hand, when the groove width is increased or the groove depth is increased, the strength of the vibrating arm portion may be reduced. In particular, when the bending rigidity in the thickness direction is reduced and the vibrating arm portion vibrates, vibration shaking in the thickness direction may occur.

  With respect to these problems, according to the present embodiment, the connecting groove portion 35a is formed on the front end side (+ Y side) of the groove portion 31a and the groove portion 32a. For this reason, when the vibrating arm portion 21 vibrates in the secondary bending mode, the portion that becomes the vibration node portion on the distal end side is likely to vibrate, and it is difficult to become a vibration node. That is, according to the present embodiment, it is possible to suppress the CI value (R2 value) in the secondary bending mode from being reduced.

Moreover, according to this embodiment, a part of 1st wall part 41a is provided in the front end side (+ Y side) of the groove parts 31a and 32a. Therefore, the CI value (R1 value) in the fundamental wave mode can be reduced.
Therefore, according to this embodiment, since it can suppress that R2 value reduces, reducing R1 value, it can suppress that the vibrating arm part 21 vibrates in a secondary bending mode.

On the other hand, according to the present embodiment, a plurality of groove portions are provided side by side in the width direction. Thereby, the 1st wall part 41a and the 2nd wall part 42a are formed, and it can suppress that the intensity | strength of the vibrating arm part 21 falls.
Moreover, since the surface area of a groove part inner wall can be enlarged by providing multiple groove parts, the surface area of the excitation electrode formed in a groove part inner wall can be enlarged. Thereby, electric field efficiency can be enlarged and CI value can be reduced as a result.

  As described above, according to the present embodiment, it is possible to obtain a piezoelectric vibrating piece that can suppress the vibration in the secondary bending mode while suppressing the strength reduction of the vibrating arm portion.

  In addition, according to the present embodiment, the connecting groove portion 35a is formed at or near the portion that becomes the vibration node portion on the distal end side when the vibrating arm portion 21 vibrates in the secondary bending mode. The portion that becomes the vibration node on the side is likely to vibrate. That is, according to this embodiment, it is possible to further suppress the vibrating arm portion 21 from vibrating in the secondary bending mode. In other words, according to this embodiment, it can suppress more that R2 value reduces.

  Further, according to the present embodiment, the connecting groove portions 35 a and 35 b provided in the vibrating arm portion 21 and the connecting groove portions 36 a and 36 b provided in the vibrating arm portion 22 are the center between the vibrating arm portions 21 and 22. Are provided symmetrically with respect to a center line P21 parallel to the length direction of the vibrating arm portions 21 and 22. Thereby, according to this embodiment, it can suppress that the vibration characteristic of the piezoelectric vibrating piece 100 becomes unstable.

  Moreover, according to this embodiment, since the connection groove part 35a is provided so that a wall part may be divided | segmented, the position which the connection groove part 35a forms can be arbitrarily determined within the range in which the wall part is formed. . Therefore, according to this embodiment, it is easy to form the connecting groove portion 35a in the portion that becomes the vibration node portion or in the vicinity thereof.

  Further, according to the piezoelectric vibrator 1 of the present embodiment, since the piezoelectric vibrating piece 100 described above is provided, a piezoelectric vibrator having excellent reliability can be obtained.

  In the present embodiment, the following configurations and methods may be employed.

  In the embodiment described above, one connection groove 35a is formed on the surface 19a of the vibrating arm portion 21, but the present invention is not limited to this. In the present embodiment, for example, a plurality of connecting groove portions may be formed on the surface 19 a of the vibrating arm portion 21.

  In the embodiment described above, the groove and the connecting groove are formed on both the front surface 19a and the back surface 19b. However, the present invention is not limited to this. In the present embodiment, for example, a groove portion may be formed on both surfaces, and a connection groove portion may be formed only on one surface, or a groove portion and a connection groove portion may be formed only on one surface. It may be.

  In the embodiment described above, at least a part of both the first wall portion 41a and the second wall portion 42a is provided on the tip side (+ Y side) from the center line P11. Not limited. In the present embodiment, how the first wall portion 41a and the second wall portion 42a are arranged within a range in which at least a part of the wall portion is provided on the tip side (+ Y side) from the center line P11. It may be.

  In the present embodiment, the piezoelectric body of the piezoelectric vibrating piece 100 may not be formed of quartz.

  In the present embodiment, the method for forming the groove 31a is not particularly limited, and any method other than etching may be used.

  Moreover, in this embodiment, the connection groove part 35a may be provided anywhere in the range which is a front end side (+ Y side) rather than the centerline P11.

(Second Embodiment)
The second embodiment is different from the first embodiment in that the connecting groove is provided at the end on the tip side of the plurality of grooves.
In the following description, the same components as those in the above-described embodiment may be omitted by appropriately attaching the same reference numerals.

FIG. 6 is a plan view showing the piezoelectric vibrating piece 200 of the present embodiment.
As shown in FIG. 6, the piezoelectric vibrating piece 200 according to the present embodiment includes a base 10, a pair of vibrating arms 221 and 222 connected to the base 10 and arranged side by side in the width direction (X-axis direction), Two support arm portions 15 and 16 connected to both sides in the width direction (X-axis direction) of the vibrating arm portions 221 and 222 in the base portion 10, and two mount portions 17 and 18 provided on the support arm portions 15 and 16. With.

The vibrating arm portions 221 and 222 include belt-like portions 211 and 212 and hammer portions 13 and 14.
A groove 231, a groove 232, and a connecting groove 235 are formed on the surface 19 a of the belt-like portion 211. The groove parts 231 and 232 are the same as the groove parts 31a and 32a of the first embodiment except that the positions connected by the connection groove part 235 are different.

  The connecting groove portion 235 connects the groove portion 231 and the groove portion 232 at the end portion (+ Y side). That is, the connecting groove 235 is formed on the tip side (+ Y side) from the center line P12 that passes through the center in the length direction (Y axis direction) of the groove parts 231 and 232 and is parallel to the width direction (X axis direction). Has been.

Since the groove portion 231 and the groove portion 232 are formed, a wall portion 241 is formed between the groove portion 231 and the groove portion 232.
The wall portion 241 is provided so as to extend from the end portion on the base 10 side (−Y side) of the groove portions 231 and 232 to the distal end side (+ Y side) in the length direction of the groove portions 231 and 232. That is, the wall portion 241 is provided so as to extend from the base portion 10 to the distal end side (+ Y side) from the center line P12. In other words, a part of the wall portion 241 is provided on the distal end side (+ Y side) of the vibrating arm portion 221 with respect to the center line P12.
In the present embodiment, since the connecting groove portion 235 is provided at the end portion (+ Y side) of the groove portions 231 and 232, the wall portion 241 is not divided and is formed integrally.

  On the back surface 19b of the belt-like portion 211, similarly to the front surface 19a, two groove portions (not shown) and a connecting groove portion (not shown) for connecting the two groove portions are formed. Each groove portion and the connecting groove portion are formed so as to overlap with the groove portions 231 and 232 and the connecting groove portion 235 in plan view (XY view), respectively.

On the surface 19 a of the vibrating arm portion 222, groove portions 233 and 234, a connecting groove portion 236, and a wall portion 242 are formed in the same manner as the vibrating arm portion 221. The same applies to the back surface 19b.
The connecting groove portion 235 formed in the vibrating arm portion 221 and the connecting groove portion 236 formed in the vibrating arm portion 222 pass through the center in the width direction (X-axis direction) between the vibrating arm portions 221 and 222, and These are provided symmetrically about a center line P22 parallel to the length direction (Y-axis direction) of the vibrating arm portions 221 and 222.

  According to the present embodiment, since the connecting groove 235 is provided at the end portion (+ Y side) of the grooves 231 and 232, it is easy to form the connecting groove 235.

(Third embodiment)
The third embodiment is different from the first embodiment in that there are three groove portions formed in each vibrating arm portion.
In the following description, the same components as those in the above-described embodiment may be omitted by appropriately attaching the same reference numerals.

FIG. 7 is a plan view showing the piezoelectric vibrating piece 300 of the present embodiment.
As shown in FIG. 7, the piezoelectric vibrating piece 300 of the present embodiment includes a base 10, a pair of vibrating arms 321 and 322 that are connected to the base 10 and arranged in the width direction (X-axis direction), Two support arm portions 15 and 16 connected to both sides in the width direction (X-axis direction) of the vibrating arm portions 321 and 322 in the base portion 10 and two mount portions 17 and 18 provided on the support arm portions 15 and 16. With.

The vibrating arm portions 321 and 322 include belt-like portions 311 and 312 and hammer portions 13 and 14.
A groove portion 331, a groove portion 332, a groove portion 333, and a connecting groove portion 337 are formed on the surface 19 a of the belt-like portion 311. The groove portions 331, 332, and 333 are the same as the groove portions 31a and 32a of the first embodiment, respectively.

  The connecting groove portion 337 connects the groove portion 331, the groove portion 332, and the groove portion 333. In other words, the inside of the groove portion 331, the inside of the groove portion 332, and the inside of the groove portion 333 are communicated by the connecting groove portion 337. The connecting groove portion 337 is formed on the front end side (+ Y side) from the center line P13 that passes through the center in the length direction (Y axis direction) of the groove portions 331, 332, and 333 and is parallel to the width direction (X axis direction). Has been. In other words, the connecting groove part 337 connects the groove part 331, the groove part 332, and the groove part 333 on the tip side (+ Y side) from the center line P13.

  By forming the groove part 331 and the groove part 332, the first wall part 341 and the second wall part 343 are formed between the groove part 331 and the groove part 332. By forming the groove part 332 and the groove part 333, the first wall part 342 and the second wall part 344 are formed between the groove part 332 and the groove part 333.

  The first wall portions 341, 342 and the second wall portions 343, 344 are the same as the first wall portion 41a and the second wall portion 42a of the first embodiment.

  Similar to the front surface 19a, the back surface 19b of the belt-like portion 311 is formed with three groove portions and a connecting groove portion that connects the three groove portions. Each groove portion and the connecting groove portion are formed so as to overlap with the groove portions 331, 332, 333 and the connecting groove portion 337 in plan view (XY view), respectively.

  On the surface 19 a of the vibrating arm portion 322, there are groove portions 334, 335, 336, a connecting groove portion 338, first wall portions 345, 346, and second wall portions 347, 348 in the same manner as the vibrating arm portion 321. Is formed. The same applies to the back surface 19b.

  The connecting groove portion 337 formed on the vibrating arm portion 321 and the connecting groove portion 338 formed on the vibrating arm portion 322 pass through the center in the width direction (X-axis direction) between the vibrating arm portions 321 and 322, and It is symmetrical with respect to a center line P23 parallel to the length direction (Y-axis direction) of the vibrating arm portions 321 and 322.

  According to the present embodiment, since the three groove portions are formed on one surface of one vibrating arm portion, the CI value can be further reduced.

  In the above-described embodiment, the connecting groove portion 337 is configured to connect the three groove portions 331, the groove portion 332, and the groove portion 333, but is not limited thereto. In this embodiment, the connection groove part 337 may be configured to connect only two adjacent groove parts among the three groove parts 331, the groove part 332, and the groove part 333.

  In the present embodiment, for example, a connecting groove portion that connects the groove portion 331 and the groove portion 332 and a connecting groove portion that connects the groove portion 332 and the groove portion 333 may be provided separately.

  In each of the embodiments described above, two or three grooves are formed on one surface of one vibrating arm, but the present invention is not limited to this. In each embodiment, four or more groove portions may be formed on one surface of one vibrating arm portion. The CI value can be reduced as the number of grooves formed on one surface of one vibrating arm portion increases.

  In each embodiment, a side arm type piezoelectric vibrating piece is used, but a tuning fork type or a center arm type may be used.

  Further, in each embodiment, the ceramic package type surface-mount type vibrator has been described as the piezoelectric vibrator using the piezoelectric vibrating piece. However, the piezoelectric vibrating piece is made up of a base substrate and a lid substrate formed of a glass material. It is also possible to apply to a glass package type piezoelectric vibrator that is bonded by anodic bonding.

(Embodiment of a device including a piezoelectric vibrator)
[Oscillator]
Next, an oscillator according to this embodiment including the piezoelectric vibrator 1 will be described.
FIG. 8 is a diagram illustrating the oscillator 1000 according to the present embodiment.
The oscillator 1000 includes a substrate 1010, an integrated circuit 1020, an electronic component 1030, and the piezoelectric vibrator 1.
The electronic component 1030 is, for example, a capacitor or the like, and is mounted on the substrate 1010. The integrated circuit 1020 is for an oscillator and is mounted on the substrate 1010.

  The integrated circuit 1020 is electrically connected to each of the piezoelectric vibrator 1 and the electronic component 1030 via a wiring (not shown). For example, the piezoelectric vibrator 1 is mounted in the vicinity of the integrated circuit 1020 on the substrate 1010. The piezoelectric vibrator 1 is the piezoelectric vibrator of the embodiment described above with reference to FIG. 1 and the like, and functions as an oscillator. At least a part of the oscillator 1000 may be appropriately molded with a resin (not shown).

  In the oscillator 1000, when electric power is supplied to the piezoelectric vibrator 1, the piezoelectric vibrating piece of the piezoelectric vibrator 1 vibrates. The vibration of the piezoelectric vibrating piece is converted into an electric signal by the piezoelectric characteristics of the piezoelectric vibrating piece. This electrical signal is output from the piezoelectric vibrator 1 to the integrated circuit 1020. The integrated circuit 1020 generates a frequency signal by performing various processes on the electrical signal output from the piezoelectric vibrator 1.

  The oscillator 1000 can be applied to, for example, a single-function oscillator for a clock, a timing control device that controls the operation timing of various devices such as a computer, and a device that provides time or a calendar. The integrated circuit 1020 is configured according to a function required for the oscillator 1000 and may include a so-called RTC (real time clock) module.

  According to this embodiment, since the piezoelectric vibrator 1 is provided, the oscillator 1000 having excellent reliability can be obtained in the same manner as described above.

[Electronics]
Next, a portable information device will be described as one form of the electronic device of this embodiment including the piezoelectric vibrator 1.
This portable information device is in the form of a wristwatch and is much smaller and lighter than a general cellular phone, but can communicate in the same way as a cellular phone. In this portable information device, a display unit such as a liquid crystal display is disposed in a portion corresponding to the dial, and time information and the like can be displayed on the display unit. In addition, this portable information device is provided with an input / output unit such as a speaker and a microphone on the inner side of the band, and can make a call using the input / output unit.

FIG. 9 is a diagram illustrating an example of the portable information device 1100 of the present embodiment.
A portable information device 1100 shown in FIG. 9 includes a timekeeping unit 1110, a display unit 1120, a communication unit 1130, a control unit 1140, a power supply unit 1150, a voltage detection unit 1160, and a power supply cutoff unit 1170.

  The control unit 1140 comprehensively controls each unit of the portable information device 1100. For example, the control unit 1140 controls time measurement by the time measuring unit 1110, display of information by the display unit 1120, communication with the outside by the communication unit 1130, and the like. The control unit 1140 includes, for example, a ROM in which a program is written in advance, a CPU that reads the program written in the ROM, executes various processes according to the program, and a RAM that is used as a work area of the CPU. .

  The timer unit 1110 includes an integrated circuit and the piezoelectric vibrator 1. This integrated circuit includes an oscillation circuit, a register circuit, a counter circuit, and an interface circuit. The piezoelectric vibrator 1 is a piezoelectric vibrator according to the above-described embodiment. The piezoelectric vibrator 1 receives the supply of electric power, and the piezoelectric vibrating piece vibrates, and converts this vibration into an electric signal corresponding to the piezoelectric characteristics of the piezoelectric vibrating piece. The electric signal output from the piezoelectric vibrator 1 is input to the oscillation circuit of the integrated circuit.

  In the integrated circuit of the timer unit 1110, the output of the oscillation circuit is binarized and counted by a register circuit and a counter circuit. The counting result is supplied to the control unit 1140 via the interface circuit. The control unit 1140 calculates time and date by executing various calculations based on the counting result from the integrated circuit, and based on the calculation result, displays various information such as time, date, and calendar on the display unit 1120. Is displayed.

  The communication unit 1130 performs communication with the outside, that is, transmission of data to the outside and reception of data from the outside. The communication unit 1130 includes a radio unit 1200, a voice processing unit 1210, a switching unit 1220, an amplification unit 1230, a voice input / output unit 1240, a telephone number input unit 1250, a ring tone generation unit 1260, and a call control memory. Part 1270.

  Radio section 1200 exchanges various data such as encoded audio data with the base station via antenna 1280. The audio processing unit 1210 decodes the data input from the radio unit 1200 and outputs the data to the amplifying unit 1230. Also, the audio processing unit 1210 encodes the data input from the amplification unit 1230 and outputs the encoded data to the radio unit 1200. The amplifying unit 1230 delivers a signal between the audio processing unit 1210 and the audio input / output unit 1240 and amplifies the delivered signal to a predetermined level as appropriate. The audio input / output unit 1240 includes a speaker, a microphone, and the like, outputs audio corresponding to the signal from the amplifying unit 1230 to the outside, and receives audio input from the outside.

  The switching unit 1220 connects the ring tone generating unit 1260 to the amplifying unit 1230 according to a command from the control unit 1140 according to a call from the base station. The ring tone generation unit 1260 outputs ring tone data to the switching unit 1220 in response to a command from the control unit 1140 according to the call from the base station. That is, the control unit 1140 causes the voice input / output unit 1240 to output a ringtone by causing the amplification unit 1230 to output ringtone data in response to a call from the base station.

  The call control memory unit 1270 stores a program related to incoming / outgoing call control of communication. The telephone number input unit 1250 includes, for example, number keys from 0 to 9 and other keys, and is used to input a telephone number of a call destination by pressing these number keys.

  The power supply unit 1150 includes, for example, a lithium ion secondary battery and supplies power to each unit of the portable information device 1100. The voltage detection unit 1160 detects the voltage supplied from the power supply unit 1150 to each unit of the portable information device 1100. The voltage detection unit 1160 notifies the control unit 1140 that the voltage is equal to or lower than the predetermined value when the detected voltage is equal to or lower than the predetermined value. This predetermined value is a value set in advance as a voltage required to stably operate the communication unit 1130, and is, for example, about 3V. Upon receiving the voltage drop notification from the voltage detection unit 1160, the control unit 1140 performs operations of at least some of the plurality of functional units including the radio unit 1200, the voice processing unit 1210, the switching unit 1220, and the ring tone generation unit 1260. Prohibited or restricted. In this case, the control unit 1140 prohibits or restricts the operation of the function unit with relatively large power consumption among the plurality of function units before the function unit with relatively small power consumption among the plurality of function units. To do. The control unit 1140 causes the display unit 1120 to display information indicating that the function is stopped or restricted due to a decrease in power supply. This display may include a character or a symbol. For example, a mode in which a cross (X) is added to the telephone icon displayed on the display unit 1120 may be used. The power cutoff unit 1170 selectively stops the supply of power to a functional unit whose function is stopped due to a voltage drop among the plurality of functional units.

  According to this embodiment, since the piezoelectric vibrator 1 is provided, the portable information device 1100 having excellent reliability can be obtained in the same manner as described above.

[Radio clock]
Next, the radio-controlled timepiece according to this embodiment including the piezoelectric vibrator 1 will be described.
The radio timepiece has a function of adjusting the time to be displayed to the time acquired from the standard radio wave. The standard radio wave is obtained by subjecting a carrier wave of a predetermined frequency to AM modulation by a modulation signal including time information called a time code. For example, in Japan, standard radio waves are transmitted from a transmitting station in Fukushima Prefecture and a transmitting station in Saga Prefecture. The standard radio wave transmitted from the transmitting station in Fukushima has a carrier frequency of 40 kHz, and the standard radio wave transmitted from the transmitting station in Saga has a carrier frequency of 60 kHz.

  FIG. 10 is a diagram showing a radio timepiece 1300 according to the present embodiment. The radio timepiece 1300 includes an antenna 1310, an amplifier 1320, a filter unit 1330, a detection rectification circuit 1340, a waveform shaping circuit 1350, a CPU 1360, and an RTC 1370.

  The antenna 1310 receives standard radio waves. The amplifier 1320 amplifies the standard radio wave signal received by the antenna 1310 and outputs the amplified signal to the filter unit 1330. The filter unit 1330 filters and tunes the signal from the amplifier 1320 and outputs the signal to the detection rectifier circuit 1340. The detection rectification circuit 1340 detects and demodulates the signal from the filter unit 1330 and outputs the signal to the waveform shaping circuit 1350. The waveform shaping circuit 1350 acquires a time code from the signal from the detection rectification circuit 1340 and supplies the time code to the CPU 1360. The CPU 1360 acquires information related to the time such as the current year, accumulated date, day of the week, and time from the time code. The RTC 1370 is a so-called real time clock, and holds information such as the current year, month, day, hour, minute, and second. The CPU 1360 reflects information related to the time acquired from the time code in information held by the RTC 1370. Information held by the RTC 1370 is read as appropriate and used to display time.

Filter unit 1330 includes a piezoelectric vibrator having a resonance frequency corresponding to the frequency of the signal to be filtered. In the filter portion 1330, the piezoelectric vibrator functions as a resonator. For example, the radio timepiece 1300 in FIG. 10 is assumed to be used in Japan, and the filter unit 1330 includes a piezoelectric vibrator 1a having a resonance frequency of 40 kHz and a piezoelectric vibrator 1b having a resonance frequency of 60 kHz. Including. Note that, in the radio timepiece 1300 that is assumed to be used in regions other than Japan, the resonance frequency of the piezoelectric vibrator of the filter unit 1330 is set according to the frequency of the carrier wave of the standard radio wave corresponding to the region used. .
In the present embodiment, the piezoelectric vibrator 1a and the piezoelectric vibrator 1b of the filter unit 1330 are respectively the same piezoelectric vibrator as the piezoelectric vibrator 1 of the above-described embodiment.

  According to this embodiment, since the piezoelectric vibrators 1a and 1b having the same configuration as the piezoelectric vibrator 1 are provided, the radio timepiece 1300 having excellent reliability can be obtained in the same manner as described above.

  In the above description, as an example of an oscillator, an electronic device, and a radio timepiece, an example including the piezoelectric vibrator 1 on which the piezoelectric vibrating piece 100 of the first embodiment is mounted is shown, but the present invention is not limited thereto. As an embodiment of an oscillator, an electronic device, and a radio-controlled timepiece, for example, a configuration including a piezoelectric vibrator on which any one of the piezoelectric vibrating pieces illustrated in the second embodiment and the third embodiment is mounted may be employed. .

  DESCRIPTION OF SYMBOLS 1, 1a, 1b ... Piezoelectric vibrator, 2 ... Package, 3 ... Package main body (base member), 4 ... Sealing plate (lid member) 10, 2020 ... Base, 19a ... Front surface (main surface), 19b ... Back surface ( Main surface) 21, 22, 221, 222, 321, 322, 2010... Vibrating arm portion, 31a, 31b, 32a, 32b, 33a, 33b, 34a, 34b, 231, 232, 233, 234, 331, 332 333, 334, 335, 336, 2040 ... groove, 35a, 35b, 36a, 36b, 235, 236, 337, 338 ... connecting groove, 41a, 41b, 43a, 43b, 341, 342, 345, 346 ... first wall Part, 42a, 42b, 44a, 44b, 343, 344, 347, 348 ... second wall part, 55a, 56a ... mounting surface, 100, 200, 300, 2 DESCRIPTION OF SYMBOLS 01 ... Piezoelectric vibration piece, 241, 242 ... Wall part, 1000 ... Oscillator, 1020 ... Integrated circuit, 1110 ... Timekeeping part, 1300 ... Radio clock, 1330 ... Filter part, 2010a, 2010b ... Vibration node part, C1 ... Cavity, P21 , P22, P23 ... center line

Claims (10)

The base,
A pair of vibrating arms connected to the base and arranged side by side in the width direction;
With
On the main surface of the vibrating arm portion, a plurality of groove portions extending in the length direction of the vibrating arm portion side by side in the width direction and a connecting groove portion connecting the adjacent groove portions are formed.
Between the adjacent groove portions, a wall portion is formed along the length direction,
At least a part of the wall portion is provided on the distal end side of the vibrating arm portion from the center in the length direction of the groove portion,
The connecting groove portion connects the adjacent groove portions on the distal end side, and a position shift between the connecting groove portion and the vibration node portion is formed at a position that is 1/6 or less of the length of the vibration arm portion. A piezoelectric vibrating piece characterized by that. 2. The piezoelectric vibrating piece according to claim 1 , wherein the connecting groove portion is formed in a portion that becomes a vibration node portion on the distal end side of the vibrating arm portion when the vibrating arm portion vibrates in a secondary bending mode. 3. The piezoelectric vibrating piece according to claim 1, wherein the connection groove portion connects the groove portions adjacent to each other at an end portion on the tip end side. 3. The piezoelectric vibrating piece according to claim 1, wherein the wall portion is divided into a first wall portion on the base portion side and a second wall portion on the distal end side by the connecting groove portion. The base,
A pair of vibrating arms connected to the base and arranged side by side in the width direction;
With
On the main surface of the vibrating arm portion, a plurality of groove portions extending in the length direction of the vibrating arm portion side by side in the width direction and a connecting groove portion connecting the adjacent groove portions are formed.
Between the adjacent groove portions, a wall portion is formed along the length direction,
The wall portion is divided by the connecting groove portion into a first wall portion on the base side and a second wall portion on the tip side,
At least a part of the wall portion is provided on the distal end side of the vibrating arm portion from the center in the length direction of the groove portion,
The connecting groove portion connects the groove portions adjacent to each other on the tip end side, and the piezoelectric vibrating piece. The connecting groove portions provided in the pair of vibrating arm portions pass through the center in the width direction between the pair of vibrating arm portions and are parallel to the center line parallel to the length direction. The piezoelectric vibrating piece according to claim 1, which is provided symmetrically. A package having a base member and a lid member that is overlapped and joined to the base member and that forms a hermetically sealed cavity with the base member;
A piezoelectric vibrator comprising: the piezoelectric vibrating piece according to claim 1 mounted on a mounting surface of the base member and housed in the cavity. An oscillator comprising the piezoelectric vibrator according to claim 7, wherein the piezoelectric vibrator is electrically connected to an integrated circuit as an oscillator. An electronic apparatus comprising the piezoelectric vibrator according to claim 7, wherein the piezoelectric vibrator is electrically connected to a timer unit. A radio timepiece comprising the piezoelectric vibrator according to claim 7, wherein the piezoelectric vibrator is electrically connected to a filter unit.

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