JP2014120890A - Piezoelectric vibration piece, piezoelectric vibrator, oscillator, electronic apparatus and radio clock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric vibration piece which has excellent vibration characteristics, a piezoelectric vibrator, an oscillator, an electronic apparatus and a radio clock which can improve producibility.SOLUTION: In a piezoelectric vibration piece 1 which includes a pair of vibration arm parts 10, 11 arranged side by side in a width direction, and a base 12 to which base end parts in a Y axis direction in the pair of vibration arm parts 10, 11 are connected, a first excitation electrode 21 is formed on one side surface of side surfaces 10a, 10b, 11a, 11b facing each other in an X direction in each of the vibration arm parts 10, 11, a second excitation electrode 22 with different polarity from the first excitation electrode 21 is formed on another side surface, and the first excitation electrode 21 and the second excitation electrode 22 vibrate each of the vibration arm parts 10, 11 along a Y-Z plane when voltage is applied between the excitation electrodes 21, 22.

Description

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

  In a cellular phone, a portable information terminal device, and the like, a piezoelectric vibrator using a crystal or the like is used as a time source, a control signal timing source, a reference signal source, and the like. Various piezoelectric vibrators of this type are provided, and one of them is a piezoelectric vibrator having a so-called tuning fork type piezoelectric vibrating piece.

Here, a conventional tuning-fork type piezoelectric vibrating piece will be briefly described. FIG. 26 is a plan view of a conventional piezoelectric vibrating piece, and FIG. 27 is a cross-sectional view taken along the line EE of FIG.
As shown in FIGS. 26 and 27, the piezoelectric vibrating piece 200 includes a pair of vibrating arm portions 210 and 211 arranged side by side in the width direction, and a base along the length direction of the pair of vibrating arm portions 210 and 211. And a base 212 that connects the ends. An electrode film 213 is formed on the outer surface of the piezoelectric vibrating piece 200, and when a voltage is applied to the electrode film 213, the pair of vibrating arm portions 210 and 211 are moved toward or away from each other (vibrating arm). It is possible to vibrate at a predetermined resonance frequency in the width direction of the portions 210 and 211.

  Incidentally, in recent years, with the downsizing of devices on which packages are mounted, further downsizing of the piezoelectric vibrating piece 200 is desired. However, when the piezoelectric vibrating piece 200 is downsized, if the width of the vibrating arm portions 210 and 211 is narrowed, the formation width of the electrode film 213 formed on the vibrating arm portions 210 and 211 is also narrowed, which contributes to vibration. It becomes difficult to apply an electric field, and an equivalent series resistance value (Crystal Impedance: CI value) rises and the quality of the output signal deteriorates. Therefore, in order to reduce the size of the piezoelectric vibrating piece 200, it is necessary to suppress the increase in the CI value.

Therefore, for example, as shown in Patent Document 1, a configuration is known in which the groove 214 is formed on both main surfaces of the vibrating arm portions 210 and 211 by etching.
According to this configuration, the pair of electrode films 213 are opposed to each other on the side surfaces of the vibrating arm portions 210 and 211 and the inner surface of the groove portion 214, so that an electric field can be efficiently applied in the facing direction. Thereby, even if the width of the vibrating arm portions 210 and 211 is reduced, the electric field efficiency can be increased, and the piezoelectric vibrating piece can be reduced in size while suppressing an increase in the CI value.

JP 2002-261558 A

Here, in order to form the groove portion 214 in the vibrating arm portions 210 and 211, the wafer is etched into the outer shape of the piezoelectric vibrating piece 200, and then the groove forming region in the vibrating arm portions 210 and 211 is further etched. Therefore, it is necessary to form the groove 214.
Therefore, there is a problem that an extra process is required for forming the groove, which leads to an increase in manufacturing man-hours and a complicated manufacturing process, resulting in a decrease in manufacturing efficiency.

In addition, since the etching of the groove 214 is performed after the outer shape of the piezoelectric vibrating piece 200 is formed, it is necessary to align the groove forming mask with the vibrating arms 210 and 211 with high accuracy.
In particular, when the alignment accuracy described above is poor and the groove portion 214 is displaced in the width direction of the vibrating arm portions 210 and 211, the axis line that bisects the vibrating arm portions 210 and 211 in the width direction is the center. The shape is different on both sides and the weight balance becomes unbalanced. As a result, the vibration balance of the vibrating arms 210 and 211 is unbalanced, resulting in a change in drive level characteristics (the behavior of the resonance frequency F with respect to the voltage applied to the piezoelectric vibrating piece 200), an increase in CI value due to vibration leakage, and the like. There is a risk of being connected.

Further, the electrode film 213 includes the groove 214 and the vibrating arm portion of the main surfaces of the vibrating arm portions 210 and 211, the portion located on the inner surface of the groove portion 214 and the portion located on the side surface of the vibrating arm portions 210 and 211. It is necessary to pattern so as to be divided at a portion located between the side surfaces of 210 and 211 (see, for example, part F in FIG. 27).
Therefore, as described above, when the groove 214 is displaced in the width direction with respect to the vibrating arm portions 210 and 211, a portion of the electrode film 213 that is removed by patterning and a main surface of the vibrating arm portions 210 and 211. The part located between the groove part 214 and the side surfaces of the vibrating arm parts 210 and 211 is displaced. In this case, a portion of the electrode film 213 located between the groove 214 and the side surfaces of the vibrating arm portions 210 and 211 is not removed from the main surfaces of the vibrating arm portions 210 and 211, and the inner surface side of the groove portion 214 is not removed. There is a possibility that polarization is insufficient between the side surfaces of the vibrating arm portions 210 and 211.

  Therefore, the present invention aims to provide a piezoelectric vibrating piece, a piezoelectric vibrator, an oscillator, an electronic device, and a radio-controlled timepiece having excellent vibration characteristics while improving the manufacturing efficiency.

  In order to solve the above-described problem, a piezoelectric vibrating piece according to the present invention includes a base portion in which a pair of vibrating arm portions arranged in the width direction and a base end portion in the extending direction of the pair of vibrating arm portions are connected. A first excitation electrode is formed on one side surface of the vibrating arm portions facing each other in the width direction, and the polarity of the first excitation electrode on the other side surface is opposite to that of the first excitation electrode. And the second excitation electrode are formed, and when the voltage is applied between the respective excitation electrodes, the first excitation electrode and the second excitation electrode are arranged along the thickness direction of the respective vibrating arm portions. It is characterized by vibrating.

According to this configuration, the first excitation electrode and the second excitation electrode having different polarities are formed on both side surfaces of the vibrating arm portion, and an electric field along the width direction of the vibrating arm portion is formed by applying a voltage to these excitation electrodes. Occurs. As a result, the vibrating arm portion vibrates at a predetermined frequency along the thickness direction of the vibrating arm portion by being displaced in a direction extending or shortening in the length direction of the vibrating arm portion.
Therefore, since it is not necessary to form a groove as in the prior art, the manufacturing efficiency can be improved.
In addition, after forming the outer shape of the piezoelectric vibrating piece, it is not necessary to form a groove portion further, so the piezoelectric vibrating piece can be formed with high accuracy, and variation in the weight balance of the vibrating arm portion can be suppressed. it can. Thereby, the change of a drive level characteristic and the increase in CI value can be suppressed, and the outstanding vibration characteristic can be exhibited.
In addition, since excitation electrodes are not formed on both main surfaces of the vibrating arm portion, the excitation electrodes can be reliably polarized between both side surfaces via both main surfaces of the vibrating arm portion.
Therefore, it is possible to provide a piezoelectric vibrating piece having excellent vibration characteristics while improving the manufacturing efficiency.

In addition, a second excitation electrode is further formed on the one side surface of the vibrating arm portions at a position offset in the thickness direction from the first excitation electrode, and a second excitation electrode is formed on the other side surface. Further, a first excitation electrode is further formed at a position offset in the thickness direction, and the first excitation electrode and the second excitation electrode face each other in the width direction between the one side surface and the other side surface. It is provided as follows.
According to this configuration, the first excitation electrode and the second excitation electrode that are opposed in the width direction of the vibrating arm portion are formed so that the polarities are opposite in the thickness direction on both side surfaces of the vibrating arm portion. It will be. Therefore, on one side and the other side in the thickness direction, the electric field generated between the first excitation electrode and the second excitation electrode facing each other in the width direction is reversed. Therefore, for example, between the first excitation electrode and the second excitation electrode that are paired on one side in the thickness direction in the same vibrating arm portion, the vibrating arm portion is displaced in the extending direction, while in the thickness direction. Between the first excitation electrode and the second excitation electrode formed on the other side, the vibrating arm portion is displaced in a contracting direction. Thereby, the vibrating arm portion can be flexibly vibrated in the thickness direction, and the vibration characteristics can be further improved.

The width dimension of the vibrating arm portion is characterized by being shorter than the thickness dimension.
According to this configuration, since the width of the vibrating arm portion is shorter than the thickness, the distance between the excitation electrodes paired in the width direction of the vibrating arm portion is shortened to improve the electric field efficiency. be able to. As a result, the CI value can be further reduced and the piezoelectric vibrating piece can be downsized. In addition, compared with the conventional configuration, in the present invention, since it is not necessary to form electrodes on the main surface of the vibrating arm portion, there is no concern that the electrodes are short-circuited even if the width dimension of the vibrating arm portion is reduced. .

The piezoelectric vibrator according to the present invention includes the above-described piezoelectric vibrating piece according to the present invention, a base member and a lid member joined to each other, and the piezoelectric vibrating piece is placed in a cavity formed between the two members. And a package for housing.
According to this configuration, since the high-quality and small piezoelectric vibrating piece having stable vibration characteristics is provided, a high-quality piezoelectric vibrator excellent in operation reliability can be obtained.

  An oscillator according to the present invention is characterized in that the piezoelectric vibrator of the present invention is electrically connected to an integrated circuit as an oscillator.

  In addition, an electronic apparatus according to the present invention is characterized in that the piezoelectric vibrator of the present invention is electrically connected to a timer unit.

  A radio timepiece according to the present invention is characterized in that the piezoelectric vibrator of the present invention is electrically connected to a filter portion.

  Since the oscillator, electronic device, and radio timepiece according to the present invention include the piezoelectric vibrator of the present invention, a high-quality product with excellent reliability can be provided.

According to the piezoelectric vibrating piece and the piezoelectric vibrator of the present invention, it is possible to provide a piezoelectric vibrating piece and a piezoelectric vibrator having excellent vibration characteristics while improving the manufacturing efficiency.
Since the oscillator, electronic device, and radio timepiece according to the present invention include the piezoelectric vibrator of the present invention, a high-quality product with excellent reliability can be provided.

It is the top view which looked at the piezoelectric vibrating piece which concerns on this embodiment of this invention from one side. It is the top view which looked at the piezoelectric vibrating piece from the other side. (A) is an A arrow directional view of FIG. 1, (b) is sectional drawing which follows the BB line of FIG. It is a perspective view of a piezoelectric vibrating piece. It is a flowchart which shows the manufacturing method of a piezoelectric vibrating piece. It is process drawing which shows the manufacturing method of a piezoelectric vibrating piece, Comprising: It is a top view of a wafer. It is an external appearance perspective view which shows a piezoelectric vibrator. FIG. 8 is an internal configuration diagram of the piezoelectric vibrator shown in FIG. 7 and is a plan view in a state where a sealing plate is removed. It is sectional drawing which follows the DD line | wire of FIG. FIG. 8 is an exploded perspective view of the piezoelectric vibrator shown in FIG. 7. It is a top view which shows the piezoelectric vibrating piece of a modification. It is a side view which shows the piezoelectric vibrating piece of a modification. It is a top view of the piezoelectric vibrating piece which shows the other structure of a modification. It is a side view of a piezoelectric vibrating piece showing another configuration of the modified example. It is a top view of the piezoelectric vibrating piece which shows the other structure of a modification. It is a side view of a piezoelectric vibrating piece showing another configuration of the modified example. It is a top view of the piezoelectric vibrating piece which shows the other structure of a modification. It is a side view of a piezoelectric vibrating piece showing another configuration of the modified example. It is a perspective view of the piezoelectric vibrating piece which shows the other structure of a modification. It is process drawing which shows the manufacturing method of the piezoelectric vibrating piece shown in FIGS. 17-19, Comprising: It is a top view of a wafer. It is a top view of the piezoelectric vibrating piece which shows the other structure of a modification. It is a side view of a piezoelectric vibrating piece showing another configuration of the modified example. It is a figure which shows one Embodiment of this invention, Comprising: It is a block diagram of an oscillator. It is a figure which shows one Embodiment of this invention, Comprising: It is a block diagram of an electronic device. It is a figure which shows one Embodiment of this invention, Comprising: It is a block diagram of a radio timepiece. It is a top view which shows the conventional piezoelectric vibrating piece. It is sectional drawing which follows the EE line | wire of FIG.

Next, embodiments of the present invention will be described with reference to the drawings.
(Piezoelectric vibrating piece)
FIG. 1 is a plan view of the piezoelectric vibrating piece according to the present embodiment as viewed from one side, and FIG. 2 is a plan view as viewed from the other side. 3A is a view taken in the direction of arrow A in FIG. 1, and FIG. 3B is a cross-sectional view taken along line BB in FIG. FIG. 4 is a perspective view of the piezoelectric vibrating piece.
As shown in FIGS. 1 to 4, the piezoelectric vibrating piece 1 of the present embodiment is a tuning fork type vibrating piece made of a piezoelectric material such as crystal, lithium tantalate, or lithium niobate, and includes a pair of vibrating arm portions 10. , 11 (first vibrating arm portion 10 and second vibrating arm portion 11), and a piezoelectric plate 13 having a base portion 12 for integrally fixing the base end portions of the pair of vibrating arm portions 10, 11, and on the piezoelectric plate 13 And an electrode film 14 formed on the substrate. The piezoelectric plate 13 of the present embodiment is obtained by slicing a quartz Lambert stone at a predetermined angle with respect to the X-axis, Y-axis, and Z-axis orthogonal to each other as a crystal crystal axis, as will be described later. 6), and the wafer 40 is formed by wet etching. In the piezoelectric plate 13 of the present embodiment, the Z axis of the crystal crystal axis substantially coincides with the thickness direction of the piezoelectric plate 13 and the Y axis is one in the length direction of the piezoelectric plate 13 (vibrating arm portions 10 and 11). The X axis coincides with the width direction of the piezoelectric plate 13 (arrangement direction of the vibrating arm portions 10 and 11).

The pair of vibrating arm portions 10 and 11 extend along the Y-axis direction and are formed side by side in parallel with the X-axis direction. The vibrating arm portions 10 and 11 of the present embodiment are formed so that the width in the X-axis direction (for example, about 20 to 30 μm) is narrower than the thickness in the Z-axis direction (for example, about 100 μm). When comparing the thickness dimension and width dimension of the vibrating arm, the conventional resonator element takes into consideration the prevention of short-circuiting of the main surface electrode, the ease of forming a groove, the ease of forming an excitation electrode on the main surface, etc. Then, it is necessary to increase the width dimension, and as a result, the relation of width dimension ≧ thickness dimension is often obtained. However, according to the present embodiment, it is not necessary to form grooves and excitation electrodes on the main surface. Therefore, it is not necessary to increase the width dimension, and the width dimension ≧ thickness dimension can be satisfied. Further, by reducing the width dimension, it is possible to improve the electric field efficiency between both side surfaces (details will be described later). As a more preferable example, the width dimension of the vibrating arm part may be 20% or more and 80% or less of the thickness dimension of the vibrating arm part. Within this range, the rigidity when the vibrating arm portion vibrates and the rigidity that can withstand external impacts can be ensured (because the width of the vibrating arm portion is too narrow, the rigidity of the vibrating arm portion is reduced). However, the dimensions may be outside this range as long as the characteristics that can be tolerated in view of the use environment can be secured. In addition, the width dimension here refers to the width dimension of the approximate average value, for example, in a shape in which the width of the vibrating arm portion changes (a shape having a reduced width portion or an enlarged portion).
Further, a connecting portion between the base portion 12 and the vibrating arm portions 10 and 11 is also formed with a portion 15 surrounded by the base portion 12, the inner side surface 10 a of the vibrating arm portion 10 and the inner side surface 11 a of the vibrating arm portion 11. .

  The electrode film 14 is formed on the pair of vibrating arm portions 10 and 11 to vibrate the pair of vibrating arm portions 10 and 11, and the first excitation electrode 21 and the second excitation electrode. A first mount electrode 23 and a second mount electrode 24 electrically connected to the electrode 22; a first lead electrode 25 electrically connecting the excitation electrodes 21 and 22 and the mount electrodes 23 and 24; and A second extraction electrode 26. The electrode film 14 is formed of, for example, a laminated film of chromium (Cr) and gold (Au).

  The excitation electrodes 21 and 22 are electrodes that vibrate the pair of vibrating arm portions 10 and 11 in a reverse phase at a predetermined resonance frequency along the YZ plane. The excitation electrodes 21 and 22 are arranged along the Y-axis direction on the inner side surfaces (one side surface or other side surfaces) 10a and 11a and the outer side surfaces (other side surfaces or one side surface) 10b and 11b of the pair of vibrating arm portions 10 and 11. And are patterned by being electrically separated from each other. In addition, the excitation electrodes 21 and 22 are formed over almost the whole area except for the tip portions of the vibrating arm portions 10 and 11 in the Y-axis direction.

  Specifically, the first excitation electrode 21 has one side in the Z-axis direction (upper side in FIG. 3) on the outer side surfaces 10b and 11b of the vibrating arm portions 10 and 11, and the other side in the Z-axis direction on the inner side surfaces 10a and 11a. It is formed on the side (lower side in FIG. 3). The second excitation electrode 22 is formed on the other side in the Z-axis direction on the outer side surfaces 10b and 11b of the vibrating arm portions 10 and 11 and on one side in the Z-axis direction on the inner side surfaces 10a and 11a. That is, the first excitation electrode 21 and the second excitation electrode 22 are arranged side by side in the Z-axis direction on the inner side surfaces 10a and 11a and the outer side surfaces 10b and 11b, respectively, and the inner side surfaces 10a and 11a and the outer side surfaces 10b and 11b are arranged. It faces in the X-axis direction. In other words, on each side surface, the first excitation electrode 21 and the second excitation electrode 22 are provided offset in the thickness direction (Z-axis direction).

  In this way, the excitation electrodes 21 and 22 are opposed so that the polarities are different in the X-axis direction between the side surfaces 10a, 10b, 11a, and 11b that are opposed to each other in the X-axis direction constituting the same vibrating arm portions 10 and 11. It is arranged. That is, the excitation electrodes 21 and 22 are paired in the X-axis direction with the same vibrating arm portions 10 and 11 interposed therebetween.

Further, the excitation electrodes 21 and 22 are disposed on one side and the other side of the vibrating arm portions 10 and 11 with the intermediate portion in the Z-axis direction, and the same side surfaces 10a, 10b, 11a and 11b are arranged so as to have different polarities. In addition, between the adjacent vibrating arm portions 10 and 11, the excitation electrodes 21 and 22 that are paired in the X-axis direction and disposed at the same position in the Z-axis direction are disposed in opposite directions.
That is, the excitation electrodes 21 and 22 that are paired in the X-axis direction are alternately arranged in the Z-axis direction between the adjacent vibrating arm portions 10 and 11. The first excitation electrode 21 and the second excitation electrode 22 are not formed on both main surfaces of the vibrating arm portions 10 and 11.

  The mount electrodes 23 and 24 are formed on the base end portion of the base portion 12 side by side in the X-axis direction. Specifically, the first mount electrode 23 is formed on one side in the X-axis direction on both main surfaces of the base 12 and on the side surface located on one side in the X-axis direction on the base 12. Further, the second mount electrode 24 is formed on the other side in the X-axis direction on both main surfaces of the base portion 12 and on the side surface located on the other side in the X-axis direction on the base portion 12.

The first lead electrode 25 includes a base end electrode 25a extending on one main surface of the base 12 in the X-axis direction, and a tip end electrode 25b formed on the vibrating arm portions 10 and 11. Yes.
The base end electrode 25a includes base end portions of the first excitation electrodes 21 formed on the outer surfaces 10b and 11b of the vibrating arm portions 10 and 11, and the first mount electrode 23 on one main surface of the base portion 12. Connected.

  The tip electrode 25b is composed of the tip portions of the first excitation electrode 21 formed on the inner side surfaces 10a and 11a and the first excitation electrode 21 formed on the outer side surfaces 10b and 11b in the same vibrating arm portion 10 and 11. Is connected. Specifically, the tip electrode 25b extends from the tip of the first excitation electrode 21 formed on the outer surfaces 10b and 11b to one main surface and the inner surface 10a of the tip of each vibrating arm portion 10 and 11. 11a is connected to the tip of the first excitation electrode 21 formed on the inner side surfaces 10a, 11a.

  The second extraction electrode 26 is formed across both main surfaces of the base portion 12 and the portion 15. The second lead electrode 26 connects the base end portions of the second excitation electrodes 22 formed on the inner side surfaces 10a, 11a of the adjacent vibrating arm portions 10, 11 on one main surface of the base portion 12. On the other main surface of the base portion 12, the base end portions of the second excitation electrodes 22 formed on the outer surfaces 10b and 11b and the second mount electrode 24 are connected.

  In the piezoelectric vibrating reed 1 formed in this way, a predetermined drive voltage is applied between the pair of excitation electrodes 21 and 22. As a result, a current can flow through the excitation electrodes 21 and 22 via the mount electrodes 23 and 24 and the extraction electrodes 25 and 26, and the first vibrating arm portions 10 and 11 make a pair in the X-axis direction. An electric field is generated between the excitation electrode 21 and the second excitation electrode 22 in a direction (X-axis direction) perpendicular to the Y-axis direction of the vibrating arm portions 10 and 11.

  Here, since the excitation electrodes 21 and 22 that are paired in the X-axis direction of the vibrating arm portions 10 and 11 are disposed in the opposite directions between the adjacent vibrating arm portions 10 and 11, the adjacent vibrating arm portions 10 and 11. , 11 generate opposite electric fields between the excitation electrodes 21 and 22 paired in the X-axis direction. Therefore, for example, between the first excitation electrode 21 and the second excitation electrode 22 paired on one side in the Z-axis direction in the vibrating arm unit 10, the direction of the vibrating arm unit 10 extends (outside in the Y-axis direction). The direction in which the vibrating arm portions 10 and 11 contract between the first excitation electrode 21 and the second excitation electrode 22 formed on one side in the Z-axis direction in the vibrating arm portion 11 (inside in the Y-axis direction). Displacement toward As a result, the vibrating arm portions 10 and 11 bend and vibrate in the opposite phase at a predetermined frequency along the YZ plane (so-called YZ bending vibration mode).

Further, since the excitation electrodes 21 and 22 are formed so that the polarities are opposite on the one side and the other side in the Z-axis direction in the same vibrating arm portions 10 and 11, one side in the Z-axis direction. On the other side, the electric field generated between the first excitation electrode 21 and the second excitation electrode 22 paired in the X-axis direction is opposite. Therefore, for example, between the first excitation electrode 21 and the second excitation electrode 22 that are paired on one side in the Z-axis direction in the same vibration arm portions 10 and 11, the direction in which the vibration arm portion 10 extends (in the Y-axis direction). In the direction in which the vibrating arms 10 and 11 contract between the first excitation electrode 21 and the second excitation electrode 22 formed on the other side in the Z-axis direction (inward in the Y-axis direction). Displace towards.
The vibration of the pair of vibrating arm portions 10 and 11 can be used as a time source, a control signal timing source, a reference signal source, and the like.

(Method for manufacturing piezoelectric vibrating piece)
Next, a method for manufacturing the above-described piezoelectric vibrating piece 1 will be described.
FIG. 5 is a flowchart showing a method of manufacturing the piezoelectric vibrating piece, and FIG. 6 is a process diagram for explaining the method of manufacturing the piezoelectric vibrating piece, and is a plan view of the wafer.
First, as shown in FIG. 5 and FIG. 6, a quartz Lambert rough is sliced at a predetermined angle to form a wafer 40 having a constant thickness (S 10). At this time, the Z axis substantially coincides with the thickness direction of the piezoelectric vibrating piece 1, the Y axis coincides with the length direction of the piezoelectric vibrating piece 1 (vibrating arm portions 10 and 11), and the X axis corresponds to the piezoelectric vibrating piece 1. The wafer 40 is sliced so as to coincide with the width direction (arrangement direction of the vibrating arm portions 10 and 11).
Next, after lapping and roughing the wafer 40, the work-affected layer is removed by etching, and then mirror processing such as polishing is performed to obtain a predetermined thickness.

Next, an outer shape forming step (S20) for forming the outer shape of the piezoelectric plate 13 on the wafer 40 is performed. Specifically, first, a metal film made of chromium (Cr) or the like is formed on both surfaces of the wafer 40, and this metal film is patterned in accordance with the outer shapes of the pair of vibrating arm portions 10 and 11 and the base portion 12. Thus, the outer pattern 41 is formed. At this time, patterning is performed collectively for the plurality of piezoelectric vibrating reeds 1 formed on the wafer 40.
Next, etching is performed from both sides of the wafer 40 using the patterned outer pattern 41 as a mask. Thereby, the region not masked by the outer pattern 41 is selectively removed, and the outer shapes of the plurality of piezoelectric plates 13 can be formed on the wafer 40. The plurality of piezoelectric plates 13 are in a state of being connected to the wafer 40 via a connecting portion (not shown) until a subsequent cutting step (S40) is performed.

  Next, an electrode film forming step (S30) for forming the electrode film 14 on the plurality of piezoelectric plates 13 is performed. First, a conductive metal film (for example, a laminated film of chromium and gold, etc.) is formed on the entire surface of the plurality of piezoelectric plates 13 by, for example, sputtering. Next, a photoresist film serving as a mask for etching is formed on the metal film by spray coating or the like, and then patterned by a photolithography technique.

  Specifically, first, a photomask (not shown) having an opening other than the formation regions of the excitation electrodes 21 and 22, the mount electrodes 23 and 24, and the extraction electrodes 25 and 26 is set on the photoresist film. Then, after exposing the photoresist film through the photomask, the photoresist film is immersed in a developing solution, so that only the photoresist film in the region not exposed to ultraviolet rays (the region covered with the photomask) is selectively removed. The In the present embodiment, when exposing a photoresist film, vertical exposure that exposes from above and below the piezoelectric plate 13 and oblique exposure that exposes from above and below the piezoelectric plate 13 are the same photo. It is preferable to carry out through a mask. That is, the photoresist film formed on both main surfaces of the piezoelectric plate 13 is exposed by vertical exposure, and the photoresist film formed on the side surface of the piezoelectric plate 13 is exposed by oblique exposure.

  Next, the metal film is etched using the photoresist film remaining after development as a mask. Thereby, the electrode film 14 described above is integrally formed. Note that the metal film on the main surface of the piezoelectric plate 13 and the metal films on the side surfaces 10a, 10b, 11a, and 11b may be separately patterned.

Next, the cutting part (S40) which cut | disconnects the connection part which has connected the wafer 40 and the piezoelectric plate 13, and isolate | separates the several piezoelectric plate 13 from the wafer 40 into pieces is performed.
As described above, a plurality of tuning fork-type piezoelectric vibrating reeds 1 are manufactured from one wafer 40 at a time.

Thus, in the present embodiment, the first excitation electrode 21 and the second excitation electrode 22 having different polarities are formed on the inner side surfaces 10a and 11a and the outer side surfaces 10b and 11b of the vibrating arm portions 10 and 11, respectively. .
According to this configuration, by forming the excitation electrodes 21 and 22 that are paired in the X-axis direction on both side surfaces 10a, 10b, 11a, and 11b of the vibrating arm portions 10 and 11, the X-axis of the vibrating arm portions 10 and 11 is formed. An electric field along the direction is generated. Accordingly, the vibrating arm portions 10 and 11 are flexibly vibrated at a predetermined frequency along the YZ plane by being displaced in a direction extending or shortening in the Y-axis direction.
Therefore, since it is not necessary to form the groove 214 as in the conventional case, the manufacturing efficiency can be improved.

In addition, since it is not necessary to perform the groove 214 forming step after the outer shape forming step (S20), the piezoelectric plate 13 can be formed with high accuracy, and the weight balance of the vibrating arm portions 10 and 11 can be improved. Variation can be suppressed. Thereby, the change of a drive level characteristic and the increase in CI value can be suppressed, and the outstanding vibration characteristic can be exhibited.
In addition, since the excitation electrodes 21 and 22 are not formed on both main surfaces of the vibrating arm portions 10 and 11, the excitation electrodes 21 and 22 are connected to both side surfaces 10a, 10b, and 11a via both main surfaces of the vibrating arm portions 10 and 11, respectively. , 11b can be reliably polarized.
Therefore, it is possible to provide the piezoelectric vibrating reed 1 having excellent vibration characteristics while improving the manufacturing efficiency.

Furthermore, in the present embodiment, as described above, the excitation electrodes 21 and 22 that are paired in the X-axis direction have opposite polarities on one side and the other side in the Z-axis direction in the same vibrating arm portion 10 and 11. Therefore, on one side and the other side in the Z-axis direction, the electric field generated between the first excitation electrode 21 and the second excitation electrode 22 paired in the X-axis direction is reversed. . Therefore, for example, between the first excitation electrode 21 and the second excitation electrode 22 that are paired on one side in the Z-axis direction in the same vibrating arm portions 10 and 11, the vibrating arm portion 10 is displaced in the extending direction. On the other hand, between the first excitation electrode 21 and the second excitation electrode 22 formed on the other side in the Z-axis direction, the vibrating arm portions 10 and 11 are displaced toward the contracting direction. Thereby, the vibrating arm portions 10 and 11 can be flexibly vibrated toward both sides in the Z-axis direction, and the vibration characteristics can be further improved.
Moreover, since the width along the X-axis direction of the vibrating arm portions 10 and 11 is shorter than the thickness along the Z-axis direction, the width along the Z-axis direction of each excitation electrode 21 and 22 is enlarged. The distance between the paired excitation electrodes 21 and 22 can be shortened to improve the electric field efficiency. As a result, the CI value can be further reduced, and the piezoelectric vibrating piece 1 can be miniaturized.

(Piezoelectric vibrator)
Next, the piezoelectric vibrator 50 including the piezoelectric vibrating piece 1 described above will be described. FIG. 7 is an external perspective view showing the piezoelectric vibrator, and FIG. 8 is an internal configuration diagram of the piezoelectric vibrator shown in FIG. 7, and is a plan view with the sealing plate removed. 9 is a cross-sectional view taken along the line DD of FIG. 8, and FIG. 10 is an exploded perspective view of the piezoelectric vibrator shown in FIG. In the following description, components that are the same as those described above are denoted by the same reference numerals and description thereof is omitted. Further, in the drawing, only the outer shape of the piezoelectric vibrating reed 1 is shown, and the electrode film 14 and the like have the same configuration as that of the above-described embodiment, and thus illustration thereof is omitted.
As shown in FIGS. 7 to 10, the piezoelectric vibrator 50 of the present embodiment includes a package 51 having a cavity C hermetically sealed therein, the above-described piezoelectric vibrating piece 1 housed in the cavity C, It is a ceramic package type surface-mount type resonator including

  The piezoelectric vibrator 50 is formed in a substantially rectangular parallelepiped shape. In this embodiment, the longitudinal direction of the piezoelectric vibrator 50 is referred to as a length direction and the short side direction is referred to as a width direction in plan view. A direction perpendicular to the width direction is referred to as a thickness direction.

  The package 51 includes a package main body (base member) 53, and a sealing plate (lid member) 54 that is bonded to the package main body 53 and forms a cavity C between the package main body 53. .

The package main body 53 includes a first base substrate 55 and a second base substrate 56 which are joined in a state of being overlapped with each other, and a seal ring 57 which is joined onto the second base substrate 56.
The first base substrate 55 is a ceramic substrate formed in a substantially rectangular shape in plan view. The second base substrate 56 is a ceramic substrate formed in a substantially rectangular shape in plan view having the same outer shape as the first base substrate 55, and is sintered in a state of being stacked on the first base substrate 55. Etc. are integrally joined together.

At the four corners of the first base substrate 55 and the second base substrate 56, cut-out portions 58 having a ¼ arc shape in plan view are formed over the entire thickness direction of both the substrates 55 and 56. The first base substrate 55 and the second base substrate 56 are formed, for example, by stacking and joining two wafer-like ceramic substrates, and then forming a plurality of through-holes penetrating both ceramic substrates in a matrix, and thereafter It is produced by cutting both ceramic substrates into a lattice shape with reference to the holes. At this time, the through hole is divided into four parts, so that the above-described notch 58 is obtained.
The upper surface of the second base substrate 56 is a mounting surface 56a on which the piezoelectric vibrating reed 1 is mounted.

  The first base substrate 55 and the second base substrate 56 are made of ceramics. Specific examples of the ceramic material include HTCC (High Temperature Co-Fired Ceramic) made of alumina and LTCC (glass ceramics). Low Temperature Co-Fired Ceramic) and the like.

  The seal ring 57 is a conductive frame-like member that is slightly smaller than the outer shape of the first base substrate 55 and the second base substrate 56, and is joined to the mounting surface 56 a of the second base substrate 56. Specifically, the seal ring 57 is bonded onto the mounting surface 56a by baking with a brazing material such as silver brazing or solder material, or formed on the mounting surface 56a (for example, in addition to electrolytic plating and electroless plating, Bonding is performed by welding or the like to a metal bonding layer formed by vapor deposition or sputtering.

The material of the seal ring 57 includes, for example, a nickel-based alloy. Specifically, the seal ring 57 may be selected from Kovar, Elinvar, Invar, 42-alloy, and the like. In particular, as the material of the seal ring 57, it is preferable to select a material having a thermal expansion coefficient close to that of the first base substrate 55 and the second base substrate 56 made of ceramic. For example, when alumina having a thermal expansion coefficient of 6.8 × 10 ⁻⁶ / ° C. is used as the first base substrate 55 and the second base substrate 56, the seal ring 57 has a thermal expansion coefficient of 5.2 × 10 ⁻ It is preferable to use ⁶ / ° C. Kovar or a 42-alloy having a thermal expansion coefficient of 4.5 to 6.5 × 10 ⁻⁶ / ° C.

The sealing plate 54 is a conductive substrate stacked on the seal ring 57, and is hermetically bonded to the package body 53 by bonding to the seal ring 57. A space defined by the sealing plate 54, the seal ring 57, and the mounting surface 56a of the second base substrate 56 functions as the above-described cavity C hermetically sealed.
In addition, as a welding method of the sealing board 54, seam welding by making a roller electrode contact, laser welding, ultrasonic welding, etc. are mentioned, for example. Further, in order to make the welding of the sealing plate 54 and the seal ring 57 more reliable, a bonding layer such as nickel or gold that is familiar to each other is provided at least on the lower surface of the sealing plate 54 and the upper surface of the seal ring 57. It is preferable to form.

Meanwhile, on the mounting surface 56a of the second base substrate 56, a pair of electrode pads 61A and 61B which are connection electrodes to the piezoelectric vibrating reed 1 are formed with a gap in the width direction, and the first base substrate 55 is provided. A pair of external electrodes 62A and 62B are formed on the lower surface of the substrate at intervals in the length direction.
The electrode pads 61A and 61B and the external electrodes 62A and 62B are, for example, a single layer film made of a single metal formed by vapor deposition, sputtering, or the like, or a stacked film in which different metals are stacked, and are electrically connected to each other.

This point will be described in detail.
The first base substrate 55 is formed with one first through electrode 63A that is electrically connected to one external electrode 62A and penetrates the first base substrate 55 in the thickness direction. One second through electrode 64A is formed which is electrically connected to the electrode pad 61A and penetrates the second base substrate 56 in the thickness direction. And between the 1st base substrate 55 and the 2nd base substrate 56, one connection electrode 65A which connects one 1st penetration electrode 63A and one 2nd penetration electrode 64A is formed. Thereby, one electrode pad 61A and one external electrode 62A are electrically connected to each other.

The first base substrate 55 is formed with the other first through electrode 63B that is electrically connected to the other external electrode 62B and penetrates the first base substrate 55 in the thickness direction. Is electrically connected to the other electrode pad 61B, and the other second through electrode 64B penetrating the second base substrate 56 in the thickness direction is formed. And between the 1st base substrate 55 and the 2nd base substrate 56, the other connection electrode 65B which connects the other 1st penetration electrode 63B and the other 2nd penetration electrode 64B is formed. Thereby, the other electrode pad 61B and the other external electrode 62B are electrically connected to each other.
The other connection electrode 65B is patterned so as to extend below the seal ring 57 along the seal ring 57, for example, so as to avoid a recess 66 described later.

  On the mounting surface 56 a of the second base substrate 56, the vibrating arm portions 10, 11 are displaced in the thickness direction due to the impact of a drop or the like on a portion facing the tip portions of the pair of vibrating arm portions 10, 11 ( A concave portion 66 is formed so as to avoid contact with the distal end portions of the vibrating arm portions 10 and 11 when it is bent and deformed. The recess 66 is a through-hole penetrating the second base substrate 56, and is formed in a square shape in plan view with rounded four corners inside the seal ring 57.

  When the piezoelectric vibrator 50 configured as described above is operated, a predetermined drive voltage is applied to the external electrodes 62A and 62B. Thereby, a current can be passed through the excitation electrodes 21 and 22 (see FIG. 1) of the piezoelectric vibrating piece 1 and the pair of vibrating arm portions 10 and 11 are vibrated at a predetermined frequency along the YZ plane. Can do. The piezoelectric vibrator 50 can be used as a time source, a control signal timing source, a reference signal source, and the like by using the vibration of the pair of vibrating arm portions 10 and 11.

  According to the piezoelectric vibrator 50 of the present embodiment, since the piezoelectric vibrator element 1 having the above-described excellent vibration characteristics is provided, the high-quality piezoelectric vibrator 50 with improved operation reliability and durability is obtained. Can do.

(Deformation example of piezoelectric vibrating piece)
Next, a modified example of the above-described piezoelectric vibrating piece will be described. FIG. 11 is a plan view showing a piezoelectric vibrating piece of a modification, and FIG. 12 is a side view. This modification is different from the above-described embodiment in that a notch 71 (notch) is formed in the base 12 of the piezoelectric vibrating piece 1. In the following description, the same components as those in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted. Further, in the drawing, only the outer shape of the piezoelectric vibrating reed 1 is shown, and the electrode film 14 and the like have the same configuration as that of the above-described embodiment, and thus illustration thereof is omitted.
In the base portion 12 of the piezoelectric vibrating piece 1 shown in FIGS. 11 and 12, a pair of notches 71 that are recessed from one main surface toward an intermediate portion in the Z-axis direction are formed at both ends in the X-axis direction. ing. These notches 71 are disposed on the distal end side of the mount portion in the base portion 12 (the connection portion between the mount electrodes 23 and 24 and the electrode pads 61A and 61B described above), and are directed toward both sides of the base portion 12 in the X-axis direction. Each open.

The cutout portion 71 of this modification can be formed by half-etching the formation region of the cutout portion 71 from one main surface side after the outer shape forming step (S20) described above.
According to this configuration, the route through which the vibration excited by the vibrating arm portions 10 and 11 is transmitted to the base portion 12 side can be narrowed, so that the vibration is confined to the vibrating arm portions 10 and 11 side and leaks to the base portion 12 side. Can be suppressed. As a result, vibration leakage can be effectively suppressed, the CI value can be prevented from increasing, and the output signal quality can be prevented from deteriorating.

Further, as shown in FIGS. 13 and 14, the notch 72 may be formed so as to penetrate the base 12 in the Z-axis direction.
Furthermore, as shown in FIGS. 15 and 16, a notch 73 that is recessed from one main surface toward an intermediate portion in the Z-axis direction may be formed over the entire X-axis direction of the base 12.

17 is a plan view of a piezoelectric vibrating piece showing another configuration of the modification, FIG. 18 is a side view, and FIG. 19 is a perspective view.
As shown in FIGS. 17 to 19, the piezoelectric vibrating reed 1 according to this modification is formed at positions where the vibrating arm portions 10 and 11 are different in the Z-axis direction (positions that do not overlap in the X-axis direction). Specifically, the vibrating arm portion 10 is formed on one side of the base portion 12 in the Z-axis direction, and the vibrating arm portion 11 is formed on the other side of the base portion 12 in the Z-axis direction. Each of the vibrating arm portions 10 and 11 is less than half the thickness of the base portion 12.
In addition, a notch 75 that is recessed toward an intermediate portion in the Z-axis direction is formed on one main surface of the base 12 over the entire X-axis direction of the base 12.

  The notch 75 of this modification can be formed collectively when etching the outer shape of the piezoelectric plate 13. That is, as shown in FIG. 20, in the outer shape pattern 74 of the outer shape forming step (S <b> 20), the outer pattern 74 on one main surface side of the wafer 40 has areas where the vibrating arm portion 11 and the notch portion 73 are formed. The external pattern 74 on the other main surface side is formed so that the formation region of the vibrating arm portion 10 is open. In this state, by performing etching from both surfaces of the wafer 40, the formation region of the vibrating arm portion 11 and the notch portion 73 among the formation region of the piezoelectric plate 13 is selectively selected from one main surface side of the wafer 40. The region where the vibrating arm portion 10 is formed is selectively etched from the other main surface side. At this time, in order to securely penetrate the wafer 40 in the Z-axis direction, it is preferable to etch more than half of the entire thickness along the Z-axis direction from both surfaces of the wafer 40. Thereby, the notch 75 of this modification is more than half of the entire thickness of the base 12 along the Z-axis direction.

  According to this configuration, the notch 73 can be formed in the same process as the outer shape of the piezoelectric plate 13, so that the manufacturing efficiency can be improved.

Furthermore, as shown in FIGS. 21 and 22, a plurality of cutout portions 75 may be formed alternately in the Y-axis direction on both main surfaces of the base portion 12. Thereby, the base 12 is formed in a spring shape that meanders in the Z-axis direction.
According to this configuration, when the vibrating arms 10 and 11 vibrate in the Z-axis direction due to an external impact or the like, the base 12 is cut when the vibrating arms 10 and 11 come into contact with the inner surface of the package 51 (see FIG. 7). It quickly elastically deforms along the Z-axis direction starting from the notch 75. Thereby, the impact in the Z-axis direction on the vibrating arm portions 10 and 11 can be absorbed, and damage to the piezoelectric vibrating piece 1 can be suppressed.

(Oscillator)
Next, an embodiment of an oscillator according to the present invention will be described with reference to FIG.
As shown in FIG. 23, the oscillator 100 according to the present embodiment is configured by configuring the piezoelectric vibrator 50 as an oscillator electrically connected to the integrated circuit 101. The oscillator 100 includes a substrate 103 on which an electronic component 102 such as a capacitor is mounted. On the substrate 103, the above-described integrated circuit 101 for the oscillator is mounted, and the piezoelectric vibrator 50 is mounted in the vicinity of the integrated circuit 101. The electronic component 102, the integrated circuit 101, and the piezoelectric vibrator 50 are electrically connected by a wiring pattern (not shown). Each component is molded with a resin (not shown).

In the oscillator 100 configured as described above, when a voltage is applied to the piezoelectric vibrator 50, the piezoelectric vibrating piece 1 in the piezoelectric vibrator 50 vibrates. This vibration is converted into an electric signal by the piezoelectric characteristics of the piezoelectric vibrating piece 1 and input to the integrated circuit 101 as an electric signal. The input electrical signal is subjected to various processes by the integrated circuit 101 and is output as a frequency signal.
Thereby, the piezoelectric vibrator 50 functions as an oscillator.
Further, by selectively setting the configuration of the integrated circuit 101, for example, an RTC (real-time clock) module or the like according to a request, the operation date and time of the device and the external device in addition to a single-function oscillator for a clock, etc. A function for controlling the time, providing a time, a calendar, and the like can be added.

  As described above, according to the oscillator 100 of the present embodiment, since the high-quality piezoelectric vibrator 50 having excellent vibration characteristics is provided, the high-quality excellent in reliability and the high-precision stable over a long period of time. An oscillator 100 that can obtain a frequency signal can be provided.

(Electronics)
Next, an embodiment of an electronic apparatus according to the invention will be described with reference to FIG. Note that a portable information device 110 having the above-described piezoelectric vibrator 50 will be described as an example of the electronic device. First, the portable information device 110 according to the present embodiment is represented by, for example, a mobile phone, and is a development and improvement of a wrist watch in the related art. The appearance is similar to that of a wristwatch, and a liquid crystal display is arranged in a portion corresponding to a dial so that the current time and the like can be displayed on this screen. Further, when used as a communication device, it is possible to perform communication similar to that of a conventional mobile phone by using a speaker and a microphone that are removed from the wrist and incorporated in the inner portion of the band. However, it is much smaller and lighter than conventional mobile phones.

  Next, the configuration of the portable information device 110 of this embodiment will be described. As shown in FIG. 24, the portable information device 110 includes a piezoelectric vibrator 50 and a power supply unit 111 for supplying power. The power supply unit 111 is made of, for example, a lithium secondary battery. The power supply unit 111 includes a control unit 112 that performs various controls, a clock unit 113 that counts time, a communication unit 114 that communicates with the outside, a display unit 115 that displays various types of information, A voltage detection unit 116 that detects the voltage of the functional unit is connected in parallel. The power unit 111 supplies power to each functional unit.

  The control unit 112 controls each function unit to control operation of the entire system such as transmission and reception of audio data, measurement and display of the current time, and the like. The control unit 112 includes a ROM in which a program is written in advance, a CPU that reads and executes the program written in the ROM, and a RAM that is used as a work area of the CPU.

  The time measuring unit 113 includes an integrated circuit including an oscillation circuit, a register circuit, a counter circuit, an interface circuit, and the like, and the piezoelectric vibrator 50. When a voltage is applied to the piezoelectric vibrator 50, the piezoelectric vibrating piece 1 vibrates, and the vibration is converted into an electric signal by the piezoelectric characteristics of the crystal and is input to the oscillation circuit as an electric signal. The output of the oscillation circuit is binarized and counted by a register circuit and a counter circuit. Then, signals are transmitted to and received from the control unit 112 via the interface circuit, and the current time, current date, calendar information, or the like is displayed on the display unit 115.

The communication unit 114 has the same functions as a conventional mobile phone, and includes a radio unit 117, a voice processing unit 118, a switching unit 119, an amplification unit 120, a voice input / output unit 121, a telephone number input unit 122, and a ring tone generation unit. 123 and a call control memory unit 124.
The wireless unit 117 exchanges various data such as audio data with the base station via the antenna 125. The audio processing unit 118 encodes and decodes the audio signal input from the radio unit 117 or the amplification unit 120. The amplifying unit 120 amplifies the signal input from the audio processing unit 118 or the audio input / output unit 121 to a predetermined level. The voice input / output unit 121 includes a speaker, a microphone, and the like, and amplifies a ringtone and a received voice or collects a voice.

In addition, the ring tone generator 123 generates a ring tone in response to a call from the base station. The switching unit 119 switches the amplifying unit 120 connected to the voice processing unit 118 to the ringing tone generating unit 123 only when an incoming call is received, so that the ringing tone generated in the ringing tone generating unit 123 is transmitted via the amplifying unit 120. To the audio input / output unit 121.
The call control memory unit 124 stores a program related to incoming / outgoing call control of communication. The telephone number input unit 122 includes, for example, a number key from 0 to 9 and other keys. By pressing these number keys and the like, a telephone number of a call destination is input.

  When the voltage applied to each functional unit such as the control unit 112 by the power supply unit 111 falls below a predetermined value, the voltage detection unit 116 detects the voltage drop and notifies the control unit 112 of the voltage drop. . The predetermined voltage value at this time is a value set in advance as a minimum voltage necessary for stably operating the communication unit 114, and is, for example, about 3V. Upon receiving the voltage drop notification from the voltage detection unit 116, the control unit 112 prohibits the operations of the radio unit 117, the voice processing unit 118, the switching unit 119, and the ring tone generation unit 123. In particular, it is essential to stop the operation of the wireless unit 117 with high power consumption. Further, the display unit 115 displays that the communication unit 114 has become unusable due to insufficient battery power.

That is, the operation of the communication unit 114 can be prohibited by the voltage detection unit 116 and the control unit 112, and that effect can be displayed on the display unit 115. This display may be a text message, but as a more intuitive display, a x (X) mark may be attached to the telephone icon displayed at the top of the display surface of the display unit 115.
In addition, the function of the communication part 114 can be stopped more reliably by providing the power supply cutoff part 126 that can selectively cut off the power of the part related to the function of the communication part 114.

  As described above, according to the portable information device 110 of the present embodiment, since the high-quality piezoelectric vibrator 50 having excellent vibration characteristics is provided, the reliability is high, and the high quality is stable over a long period of time. The portable information device 110 that can display accurate clock information can be provided.

(Radio watch)
Next, an embodiment of a radio timepiece according to the present invention will be described with reference to FIG.
As shown in FIG. 25, the radio timepiece 130 of this embodiment includes a piezoelectric vibrator 50 electrically connected to the filter unit 131. The radio timepiece 130 receives a standard radio wave including timepiece information and is accurate. It is a clock with a function of automatically correcting and displaying the correct time.
In Japan, there are transmitting stations (transmitting stations) that transmit standard radio waves in Fukushima Prefecture (40 kHz) and Saga Prefecture (60 kHz), each transmitting standard radio waves. Long waves such as 40 kHz or 60 kHz have the property of propagating the surface of the earth and the property of propagating while reflecting the ionosphere and the surface of the earth, so the propagation range is wide, and the above two transmitting stations cover all of Japan. doing.

Hereinafter, the functional configuration of the radio timepiece 130 will be described in detail.
The antenna 132 receives a long standard wave of 40 kHz or 60 kHz. The long-wave standard radio wave is obtained by subjecting time information called a time code to AM modulation on a 40 kHz or 60 kHz carrier wave. The received long standard wave is amplified by the amplifier 133 and filtered and tuned by the filter unit 131 having the plurality of piezoelectric vibrators 50.
The piezoelectric vibrator 50 in this embodiment includes crystal vibrator portions 138 and 139 having resonance frequencies of 40 kHz and 60 kHz that are the same as the carrier frequency described above.

Further, the filtered signal having a predetermined frequency is detected and demodulated by the detection and rectification circuit 134.
Subsequently, the time code is taken out via the waveform shaping circuit 135 and counted by the CPU 136. The CPU 136 reads information such as the current year, accumulated date, day of the week, and time. The read information is reflected in the RTC 137, and accurate time information is displayed.
Since the carrier wave is 40 kHz or 60 kHz, the crystal vibrator units 138 and 139 are preferably vibrators having the tuning fork type structure described above.

  In addition, although the above-mentioned description was shown in the example in Japan, the frequency of the long standard wave is different overseas. For example, in Germany, a standard radio wave of 77.5 KHz is used. Accordingly, when the radio timepiece 130 that can be used overseas is incorporated in a portable device, the piezoelectric vibrator 50 having a frequency different from that in Japan is required.

  As described above, according to the radio-controlled timepiece 130 of the present embodiment, since the high-quality piezoelectric vibrator 50 having excellent vibration characteristics is provided, the quality is excellent with reliability and the stability is stable over a long period of time. It is possible to provide a radio timepiece 130 that can count time with high accuracy.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, in the above-described embodiment, the ceramic package type piezoelectric vibrator 50 is described as an example of the piezoelectric vibrator. However, the present invention is not limited to this, and for example, a glass package type piezoelectric vibrator may be used.
In addition, the base substrate is configured by the two substrates of the first base substrate 55 and the second base substrate 56, but the base substrate may be configured by one substrate and the recess 66 may be formed in the mounting surface 56a. . However, as described above, a two-substrate configuration of the first base substrate 55 and the second base substrate 56 is preferable. In this case, after forming the through hole in the second base substrate 56, the recess 66 can be easily formed by joining both the base substrates 55, 56, so the process and time spent for forming the recess can be reduced.
Alternatively, a cylinder package type piezoelectric vibrator or a cylinder package type piezoelectric vibrator may be further solidified with a mold resin portion to form a surface mount type piezoelectric vibrator.

In the above-described embodiment, the configuration in which the excitation electrodes 21 and 22 that are paired in the X-axis direction are formed in two stages in the Z-axis direction in the same vibrating arm portions 10 and 11 is not limited thereto. It may be formed on at least one side in the Z-axis direction.
The positions and shapes of the mount electrodes 23 and 24 and the extraction electrodes 25 and 26 can be appropriately changed in design.

  In addition, in the range which does not deviate from the meaning of this invention, it is possible to replace suitably the component in the embodiment mentioned above by the known component, and you may combine each modification mentioned above suitably.

DESCRIPTION OF SYMBOLS 1 ... Piezoelectric vibration piece 10 ... 1st vibration arm part (vibration arm part) 10a ... Inner side surface (one side surface) 10b ... Outer side surface (other side surface) 11 ... 2nd vibration arm part 11a ... Inner side surface (one side surface) 11b ... External side surface (other side surface) 12 ... base 21 ... first excitation electrode 22 ... second excitation electrode 50 ... piezoelectric vibrator 53 ... package body (base member) 54 ... sealing plate (lid member) 100 ... oscillator 101 ... integrated circuit 110 ... Portable information device (electronic device) 113 ... Timekeeping unit of electronic device 130 ... Radio clock 131 ... Filter unit C ... Cavity

Claims (8)

A pair of vibrating arms arranged side by side in the width direction;
In the piezoelectric vibrating piece comprising: a base portion to which a base end portion in the extending direction of the pair of vibrating arm portions is connected;
Of the side surfaces facing each other in the width direction of each vibrating arm portion, a first excitation electrode is formed on one side surface, and a second excitation electrode having a polarity different from that of the first excitation electrode is formed on the other side surface,
1. The piezoelectric vibrating piece according to claim 1, wherein the first excitation electrode and the second excitation electrode vibrate the vibrating arm portions along the thickness direction when a voltage is applied between the excitation electrodes. A second excitation electrode is further formed on the one side surface at a position offset in the thickness direction from the first excitation electrode.
A first excitation electrode is further formed on the other side surface at a position offset in the thickness direction from the second excitation electrode,
2. The piezoelectric vibrating piece according to claim 1, wherein a first excitation electrode and a second excitation electrode are provided so as to face each other in the width direction between the one side surface and the other side surface.   3. The piezoelectric vibrating piece according to claim 1, wherein a width dimension of the vibrating arm portion is shorter than a thickness dimension of the vibrating arm portion.   4. The piezoelectric vibrating piece according to claim 1, wherein a width dimension of the vibrating arm portion is 20% or more and 80% or less of a thickness dimension of the vibrating arm portion. 5. The piezoelectric vibrating piece according to any one of claims 1 to 4,
A piezoelectric vibrator comprising: a base member and a lid member joined to each other, and a package for accommodating the piezoelectric vibrating piece in a cavity formed between the two members.   6. An oscillator, wherein the piezoelectric vibrator according to claim 5 is electrically connected to an integrated circuit as an oscillator.   6. An electronic apparatus, wherein the piezoelectric vibrator according to claim 5 is electrically connected to a timer unit.   6. A radio timepiece wherein the piezoelectric vibrator according to claim 5 is electrically connected to a filter portion.

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