JP2019161270A - Piezoelectric vibrator, oscillator, electronic device, and radio clock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To firmly maintain a tight seal between a package main body accommodating a piezoelectric vibrating piece and a closing plate, and to prevent foreign matter from entering when welding the closing plate to the package main body. A piezoelectric vibrator 42 is a rectangular parallelepiped box having a piezoelectric vibrating piece 22 that vibrates at a predetermined frequency when a voltage is applied, and a frame portion 68 and a bottom portion 70, and the piezoelectric vibrating piece 22 is housed therein. A package main body 48 including a housing portion 46, a closing plate 50 welded to the package main body 48 to close the housing portion 46, and a blocking portion that blocks the progress of foreign matter from the corner side of the frame portion 68 to the housing portion 46. 76 and. [Selection diagram] Fig. 2

Description

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

  There is a piezoelectric vibration device in which a container having a housing space for electronic component elements and a side wall is hermetically joined with a lid through a brazing material (see, for example, Patent Document 1).

JP 2013-98594 A

  In the above-described piezoelectric vibration device, a groove is formed on the top surface of the side wall, and the brazing material extends from the opening end on the inner peripheral side of the groove to the region corresponding to the inner side of the imaginary line extending vertically upward from the opening end of the lid. The fillet is formed and the lid and the container are joined.

  Some piezoelectric vibrators have a structure in which a piezoelectric vibrating piece is housed in a housing portion of a package body, and the package body and a closing plate (lid plate) are welded. In such a piezoelectric vibrator, it is desired to prevent foreign matters such as splash generated during welding from entering the housing portion of the package body. In order to suppress the generation of foreign matter, it is conceivable to reduce the applied voltage at the time of welding. However, if the applied voltage is low, the welding strength is lowered and the sealing performance between the package body and the closing plate is lowered.

  An object of the present application is to firmly maintain the sealing property between the package main body that accommodates the piezoelectric vibrating piece and the closing plate, and to prevent foreign matters from entering when the closing plate is welded to the package main body.

  In the first aspect, the package main body includes a piezoelectric vibrating piece that vibrates at a predetermined frequency when a voltage is applied, and a rectangular parallelepiped box shape having a frame portion and a bottom portion, in which the piezoelectric vibrating piece is housed. And a closing plate that is welded to the package body and closes the housing portion, and a blocking portion that blocks the progress of foreign matter from the corner side of the frame portion to the housing portion.

  In this piezoelectric vibrator, the piezoelectric vibrating reed is accommodated in the accommodating portion of the rectangular parallelepiped box-shaped package body, and the accommodating portion is closed by welding the closing plate to the package body.

  The piezoelectric vibrator has a blocking portion, and the movement of foreign matter from the corner side of the frame portion of the package body to the housing portion is blocked by the blocking portion. For example, even if foreign matter such as splash occurs during welding of the package body and the closing plate (lid plate), the foreign matter is prevented from entering the housing portion of the package body. Thereby, it is possible to maintain good vibration characteristics as a piezoelectric vibrator.

  In addition, it is not necessary to reduce the applied voltage during welding in order to prevent foreign matter generated during welding from entering the housing portion. By sufficiently increasing the applied voltage at the time of welding, the package body and the closing plate can be reliably welded, and the sealing performance can be kept strong.

  In a 2nd aspect, in the 1st aspect, the said interruption | blocking part contains the thick part which makes the corner | angular part of the said frame part thick toward the said accommodating part by the said planar view.

  In this way, the blocking portion can be formed with a simple structure in which the corner portion of the frame portion is thickened toward the housing portion.

  In a 3rd aspect, the said thick part is curving convexly toward the said accommodating part in the said 2nd aspect in the 2nd aspect.

  Compared with the structure in which the thick-walled portion is not curved in this way, it is possible to reliably suppress the progression of foreign matter to the housing portion.

  In the fourth aspect, in the second or third aspect, the frame part and the thick part are flush with each other on the side facing the blocking plate.

  Since the gap between the frame part and the thick part is constant between the closing plates, the progress of the foreign matter to the accommodating part can be reliably suppressed as compared with a structure in which the gap is widened in the thick part, for example.

  According to a fifth aspect, in any one of the first to fourth aspects, the blocking portion has a gap from the closing plate in the frame portion closer to the housing portion than the corner portion of the closing plate in the plan view. Including a groove formed.

  Thus, the blocking part can be formed with a simple structure in which the groove part is provided in the frame part.

  According to a sixth aspect, in the fifth aspect, the groove portion has two sides in a direction along the frame portion in the plan view.

  Therefore, compared with the structure in which the groove portion has only one side along the frame portion, it is possible to more reliably suppress the progress of the foreign matter to the housing portion.

  In a seventh aspect, the piezoelectric vibrator according to any one of the first to sixth aspects is provided, and the piezoelectric vibrator is electrically connected to an integrated circuit as an oscillator.

  A piezoelectric vibrator electrically connected to an integrated circuit as an oscillator has a blocking portion. Since the foreign matter generated at the time of welding the package body and the closing plate (lid plate) is suppressed from entering the housing portion of the package body, good oscillation characteristics can be obtained as an oscillator.

  In an eighth aspect, the piezoelectric vibrator according to any one of the first to sixth aspects is provided, and the piezoelectric vibrator is electrically connected to a time measuring unit.

  The piezoelectric vibrator electrically connected to the timing unit has a blocking part. Since foreign matter generated during welding of the package main body and the closing plate (lid plate) is suppressed from entering the housing portion of the package main body, good timing characteristics can be obtained as an electronic device.

  In the ninth aspect, any one of the first to sixth piezoelectric vibrators is provided, and the piezoelectric vibrator is electrically connected to the filter portion.

  The piezoelectric vibrator electrically connected to the filter part has a blocking part. Since the foreign matter generated at the time of welding between the package main body and the closing plate (lid plate) is suppressed from entering the housing portion of the package main body, good characteristics can be obtained as a radio timepiece.

  In the present application, it is possible to firmly maintain the sealing property between the package main body that accommodates the piezoelectric vibrating piece and the closing plate, and to prevent foreign matters from entering when the closing plate is welded to the package main body.

FIG. 1 is a perspective view showing the piezoelectric vibrator of the first embodiment. FIG. 2 is an exploded perspective view showing the piezoelectric vibrator of the first embodiment. FIG. 3 is a plan view showing the internal structure of the piezoelectric vibrator of the first embodiment. 4 is a cross-sectional view taken along line 4-4 of FIG. 1 showing the piezoelectric vibrator of the first embodiment. FIG. 5 is a sectional view taken along line 5-5 of FIG. 1 showing the piezoelectric vibrator of the first embodiment. FIG. 6 is a flowchart showing a process of manufacturing the piezoelectric vibrating piece according to the first embodiment. FIG. 7 is an explanatory view showing the steps of manufacturing the piezoelectric vibrating piece of the first embodiment in order from (A) to (E). FIG. 8 is an explanatory view showing the steps of adhering the piezoelectric vibrating piece to the cavity of the piezoelectric vibrator in order from (A) to (C) in the first embodiment. FIG. 9 is an explanatory view showing a process of welding the closing plate to the cavity body in the first embodiment. FIG. 10 is an explanatory diagram showing a partially enlarged piezoelectric vibrator according to the first embodiment. FIG. 11 is an explanatory diagram illustrating a partially enlarged piezoelectric vibrator of a comparative example. FIG. 12 is a plan view showing a piezoelectric vibrator of a modification of the first embodiment. FIG. 13 is an exploded perspective view showing the piezoelectric vibrator of the second embodiment. FIG. 14 is a plan view showing the internal structure of the piezoelectric vibrator of the second embodiment. FIG. 15 is a cross-sectional view showing the piezoelectric vibrator of the second embodiment in the same cross section as FIG. FIG. 16 is an explanatory diagram showing a partially enlarged piezoelectric vibrator according to the second embodiment. FIG. 17 is an exploded perspective view showing the piezoelectric vibrator of the third embodiment. FIG. 18 is a plan view showing the internal structure of the piezoelectric vibrator of the third embodiment. FIG. 19 is a cross-sectional view showing the piezoelectric vibrator of the third embodiment in the same cross section as FIG. FIG. 20 is a configuration diagram showing an oscillator using the piezoelectric vibrator of the present embodiment. FIG. 21 is a configuration diagram showing an electronic apparatus using the piezoelectric vibrator of the present embodiment. FIG. 22 is a block diagram showing a radio timepiece using the piezoelectric vibrator of the present embodiment.

  The piezoelectric vibrator 42 according to the first embodiment of the present invention will be described in detail with reference to the drawings. The piezoelectric vibrator 42 of the present embodiment has a structure in which the piezoelectric vibrating piece 22 (see FIGS. 2 and 3 to 5) is accommodated in the package body 48 (accommodating portion 46). In the drawing, the width direction, the longitudinal direction, and the thickness direction of the piezoelectric vibrator 42 are indicated by arrows W, L, and T, respectively. The width direction, the longitudinal direction, and the thickness direction of the piezoelectric vibrator 42 are the same as the width direction, the longitudinal direction, and the thickness direction of the piezoelectric vibrating piece 22 accommodated in the accommodation portion 46.

  Furthermore, in the drawing, three arrows of X, Y, and Z orthogonal to each other are shown. 1 to 5, the arrow X and the opposite -X direction correspond to the width direction, the arrow Y and the opposite -Y direction correspond to the longitudinal direction, and the arrow Z and the opposite -Z direction correspond to the thickness direction. .

  The piezoelectric vibrating piece 22 is formed of a piezoelectric material such as quartz, lithium tantalate, or lithium niobate, and is a member that vibrates when a predetermined voltage is applied. The piezoelectric vibrating piece 22 of the present embodiment has a pair of vibrating arm portions 26 as shown in FIG. 2, and may be referred to as a tuning fork type. However, the specific shape of the piezoelectric vibrating piece 22 is not limited to the tuning fork type.

  The piezoelectric vibrating piece 22 has a plate-like base portion 24. In the present embodiment, the base 24 has a rectangular shape with the long side 24L in the arrow W direction when viewed in the thickness direction (the direction of the arrow D1). That is, the direction of the long side 24 </ b> L of the base portion 24 matches the width direction of the piezoelectric vibrating piece 22.

  A pair (two) of vibrating arm portions 26 extend from the base portion 24 in the arrow Y direction. The two vibrating arm portions 26 are parallel and aligned in the arrow W direction in plan view. In the present embodiment, each of the vibrating arm portions 26 is integrally formed with the base portion 24 and extends from one of the long sides 24 </ b> L of the base portion 24.

  Further, a pair (two) of supporting arm portions 28 are extended from the base portion 24. Each of the support arm portions 28 is located on both outer sides in the arrangement direction (arrow W direction) of the vibrating arm portions 26 in plan view.

  In the present embodiment, the support arm portion 28 has a first extending portion 30A extending outward in the width direction from each of the short sides 24S of the base portion 24, and an arrow from the extending end portion of the first extending portion 30A. It is the shape which has the 2nd extension part 30B extended in the Y direction. The second extending portion 30 </ b> B in the support arm portion 28 is positioned in parallel with the vibrating arm portion 26 on both outer sides in the direction in which the vibrating arm portions 26 are arranged (arrow W direction). The extended tip 28T of the support arm 28 is closer to the base 24 than the extended tip 26T of the vibrating arm 26.

  As shown in FIG. 3, the piezoelectric vibrating piece 22 has a line-symmetric shape with respect to the center line CL- 1 in the width direction of the base 24.

  An excitation electrode (not shown) is provided on the surface of the piezoelectric vibrating piece 22, and the piezoelectric vibrating piece 22 vibrates at a predetermined frequency by applying a voltage to the excitation electrode. In the piezoelectric vibrating piece 22 of the present embodiment, the concave portions 26H are formed on both surfaces in the thickness direction of the vibrating arm portion 26 to increase the surface area, and the excitation electrode can be provided in a wide range.

  As shown in FIGS. 1 to 5, the piezoelectric vibrator 42 has a package 44. In the present embodiment, the package 44 is a substantially rectangular parallelepiped box-shaped member, and the inside is the accommodating portion 46. The piezoelectric vibrating piece 22 is accommodated in the accommodating portion 46 in an airtight state.

  The package 44 includes a package main body 48 whose one surface (the upper surface in FIGS. 5 and 7) is open, and a flat closing plate 50 that closes the package main body 48 from the open portion side. Yes.

  The package body 48 includes a flat package plate 52, a frame package frame 54, and a frame seal frame 56. In the present embodiment, the package plate 52, the package frame 54, and the seal frame 56 are all made of ceramic, and are formed by, for example, superposing and sintering ceramic green sheets together. The frame portion 68 has a rectangular frame shape having long sides 68LA and 68LB and short sides 68SC and 68SD. In FIG. 2, for convenience of illustration, the package frame 54 and the seal frame 56 are shown in a separated state, but as described above, these are integrated.

  The package plate 52 forms the bottom 69 of the package body 48. That is, the package body 48 includes a bottom portion 69 and a frame portion 68, and has a structure having an open surface 44H in which a surface opposite to the bottom portion 69 is open. The closing plate 50 is attached to the open surface 44H, and the package body 48 is closed from the open portion side.

  In the present embodiment, the outer side of the package plate 52, the outer side of the package frame 54, and the outer side of the seal frame 56 have the same shape in plan view (viewed in the direction of arrow D1). In the present embodiment, the outer shapes of the package plate 52, the package frame 54, and the seal frame 56 are the same rectangular shape. In addition, arc-shaped cutouts 48K having a central angle of 90 degrees are provided in the thickness direction at the four corners 68AC, 68AD, 68BC, and 68BD of the package body 48.

  2 to 5, the inner side of the package frame 54 and the inner side of the seal frame 56 have the same shape in plan view. In the present embodiment, both the inside of the package frame 54 and the inside of the seal frame 56 are rectangles with arcuate corners.

  From each of the long sides 54L (see FIG. 2) of the package frame 54, support portions 58 are formed that protrude inward of the package frame 54 in plan view. The support portion 58 is a portion that supports the piezoelectric vibrating piece 22 in the housing portion 46.

  As shown in FIG. 3, the position of the support portion 58 in plan view is a position that overlaps a part of the support arm portion 28 in the piezoelectric vibrating piece 22 but does not overlap a portion other than the support arm portion 28.

  As shown in FIGS. 2 to 4, an electrode pad 60 that is electrically connected to the piezoelectric vibrating piece 22 is provided on the upper surface of the support portion 58. The support arm 28 is bonded to the electrode pad 60 by the conductive adhesive 62 on the electrode pad 60. That is, the piezoelectric vibrating reed 22 is attached to the package 44 by electrically connecting and supporting the support arm portion 28 with the conductive adhesive 62 to the support portion 58 of the bottom surface 44B of the package 44. is there.

  A through electrode 64 is provided in the support portion 58 so as to penetrate the support portion 58, and the outside of the piezoelectric vibrator 42 (external electrode 66 described later) is passed through the through electrode 64, the electrode pad 60, and the conductive adhesive 62. ), A predetermined voltage can be applied to the piezoelectric vibrating piece 22.

  A pair of external electrodes 66 are provided on the lower surface of the package plate 52, that is, on the outer surface of the package 44 with a gap in the longitudinal direction of the package plate 52. As shown in FIG. 4, the package plate 52 is provided with a through electrode 65 that penetrates the package plate 52 in the thickness direction, and the through electrode 65 and the through electrode 64 are electrically connected by an internal wiring 67. That is, the electrode pad 60 and the external electrode 66 are electrically connected via the through electrode 65, the internal wiring 67, and the through electrode 64.

  As shown in FIGS. 4, 5, and 7, the closing plate 50 is a member formed in a flat plate shape from a conductive material. In plan view, the outer shape of the closing plate 50 is smaller than the outer side of the seal frame 56. When the closing plate 50 is joined to the seal frame 56, the space between the package body 48 and the closing plate 50 becomes a housing portion 46 that houses the piezoelectric vibrating piece 22.

  The package plate 52, the package frame 54, and the seal frame 56 are made of, for example, ceramics as described above. More specifically, examples include HTCC (High Temperature Co-Fired Ceramic) made of alumina, LTCC (Low Temperature Co-Fired Ceramic) made of glass ceramic, and the like.

  For example, the closing plate 50 has a structure in which a metal such as Kovar (nickel and cobalt alloy) is punched into a flat plate, and one or a plurality of plating layers are provided on both surfaces of the substrate. Can do. As the plating layer, for example, an alloy in which nickel and phosphorus, tin and copper, gold and tin, silver and copper, and the like are combined can be used.

  The closing plate 50 can be joined to the package body 48 by welding such as seam welding, laser welding, or ultrasonic welding. In this embodiment, as will be described later, seam welding is used, and the periphery of the closing plate 50 is welded to the open surface 44H, which is the upper surface of the seal frame 56, by the welded portion 74. The seal frame 56 is provided with a metallized layer (not shown) at a portion facing the closing plate 50. The sealing frame 56 and the closing plate 50 are welded by melting the plating layer on the closing plate 50 side by welding.

  As shown in FIG. 2 to FIG. 5, at the positions of the four corners 68AC, 68AD, 68BC, 68BD in the seal frame 56, the frame 68 is partially thickened toward the housing 46 side. A portion 78 is provided. The thick part 78 is an example of the blocking part 76. The thick portions 78 are located closer to the accommodating portion 46 in plan view than the four corner portions 50AC, 50AD, 50BC, 50BD of the corresponding closing plate 50. Even if a foreign object tries to enter the accommodating part 46 from the corners 68AC, 68AD, 68BC, 68BD side of the seal frame 56, the thick part 78 increases the distance of the substantial entry path, so that the entry is blocked. For example, when welding the closing plate 50 to the package main body 48, it is possible to suppress the splash generated by the welding from reaching the housing portion 46.

  In the present embodiment, the thick portion 78 is convexly curved toward the accommodating portion 46. Further, the frame portion 68 and the thick portion 78 are flush with the surface facing the closing plate 50 in each case.

  Next, a method for manufacturing the piezoelectric vibrating piece 22 will be described.

  First, a quartz Lambert rough is sliced to obtain a wafer S having a certain thickness. After the wafer S is lapped and roughly processed, the work-affected layer is removed by etching, and then mirror polishing such as polishing is performed to prepare a wafer S having a predetermined thickness (for example, 80 μm) (step of FIG. 6). S1).

  Next, as shown in FIG. 7A, an etching protective film 70 and an outer shape photoresist film 73 are formed on both surfaces of the wafer S (step S2 shown in FIG. 6). The etching protective film 70 is a laminated film in which, for example, an etching protective film 71 in which chromium (Cr) is formed to several tens of nm and an etching protective film 72 in which gold (Au) is formed to several tens of nm are sequentially laminated.

  In step S2, first, an etching protection film 71 and an etching protection film 72 are sequentially formed on both surfaces of the wafer S by a sputtering method, a vapor deposition method, or the like.

  Next, a resist material is applied on the etching protection film 70 by a spin coat method or the like, and an outer-shape photoresist film 73 is formed.

  As the resist material used in this embodiment, a rubber negative resist mainly composed of cyclized rubber (for example, cyclized isoprene) can be suitably used. The rubber-based negative resist is a resist purified by dissolving cyclized rubber in an organic solvent, adding a bisazide photosensitizer, filtering, and removing impurities.

  Next, both surfaces of the wafer S on which the etching protective film 70 and the outer photoresist film 73 are formed are exposed and developed in a lump using a photomask on which an outer pattern is drawn. Thereby, as shown in FIG. 9B, an outer pattern 73A is formed in the outer photoresist film 73 (step S3 in FIG. 8). The outer shape pattern 73 </ b> A has a shape along the outer shape of the target piezoelectric vibrating piece 22.

  Next, etching is performed using the external photoresist film 73 on which the external pattern 73A is formed as a mask, and only the etching protective film 72 of the unmasked etching protective film 70 is selectively removed (step S4 in FIG. 6). .

  Next, after the etching process, the outer photoresist film 73 on which the outer pattern 73A is formed is peeled off (step S5 in FIG. 6). Thereby, an outer pattern 72A (see FIG. 7C) is formed in the etching protective film 72.

  For the etching process, a wet etching method in which the wafer S on which the etching protective film 70 and the outer photoresist film 73 are formed is immersed in a chemical solution can be used. Specifically, for example, the etching protective film 72 formed with gold (Au) can be etched using iodine as a chemical solution.

  Next, etching is performed using the etching protection film 72 as a mask, and the etching protection film 71 of the etching protection film 70 that is not masked is selectively removed. As a result, as shown in FIG. 7C, an outer shape pattern 71A is formed in the etching protective film 71. In the etching process, a wet etching method in which the wafer S on which the etching protective film 71 is formed is immersed in a chemical solution can be used. Specifically, for example, the etching protective film 71 formed with chromium (Cr) can be etched using potassium ferricyanide as a chemical solution.

  Next, as shown in FIG. 7D, etching is performed using the external pattern 70A as a mask, and the unmasked wafer S is selectively removed (step S6 shown in FIG. 6, etching process). For this etching process, a wet etching method in which the wafer S on which the outer pattern 70A is formed is immersed in a chemical solution can be used. For example, a wafer made of quartz can be etched using hydrofluoric acid as a chemical solution. In this case, the etching time can be about 10 hours.

  Next, after the etching process, the etching protective film 70 on which the external pattern 70A is formed is peeled off (step S7 shown in FIG. 6, mask removal process). Thereby, as shown in FIG. 7E, the piezoelectric vibrating piece 22 is obtained.

  The piezoelectric vibrating piece 22 obtained in this way is attached to the package body 48 by the steps shown in FIG.

  First, as shown in FIG. 8A, an uncured conductive adhesive 62 is applied to the upper surface of the electrode pad 60 of the support portion 58 provided in the package frame 54. In the present embodiment, an adhesive having conductivity and thermosetting is used.

  Next, as shown in FIG. 8B, a part of the support arm portion 28 of the piezoelectric vibrating piece 22 is brought into contact with the uncured conductive adhesive 62 in the support portion 58.

  Next, the uncured conductive adhesive 62 is heated and cured. Accordingly, the support arm portion 28 of the piezoelectric vibrating piece 22 is bonded to the support portion 58 of the package 44 by the cured conductive adhesive 62. As shown in FIG. 8C, the piezoelectric vibrating piece 22 is supported in a state parallel to the lower surface of the package frame 54, and the pair of support arm portions 28 are electrically bonded to the electrode pads 60, respectively. It is mounted in an electrically connected state via the agent 62.

  In this manner, the closing plate 50 is attached to the package body 48 to which the piezoelectric vibrating piece 22 is attached, and the accommodating portion 46 is closed.

  In the present embodiment, the closing plate 50 is attached to the package body 48 by welding. In this case, as shown in FIG. 9, the closing plate 50 is placed at a predetermined position of the package body 48, and the periphery of the closing plate 50 is surrounded all around by using a welding electrode 80 (for example, a roller electrode for seam welding). Then, welding is performed to the open surface 44H of the package body 48.

  Specifically, two welding electrodes 80 are used, and one welding electrode 80 is moved from the corner 68AC to the corner 68AD along the long side 68LA shown in FIG. Is moved from the corner 68BC to the corner 68BD along the long side 68LB. Next, one electrode is moved along the short side 68SD from the corner 68AD to the corner 68BD, and the other electrode is moved along the short side SC from the corner 68AC to the corner 68BC. Thus, the piezoelectric vibrator 42 is obtained.

  When the closing plate 50 is welded to the package body 48, the voltage applied to the welding electrode 80 may be increased in the vicinity of the corners 68AC, 68AD, 68BC, and 68BD as compared with other portions. As a result, the closing plate 50 is more strongly welded to the package body 48 at the initial and final stages of welding.

  Thus, when the voltage applied to the welding electrode 80 is increased, foreign matter such as splash may be generated and scattered. When the foreign matter enters the housing portion 46, the characteristics of the piezoelectric vibrating piece 22 may be affected. For example, when a foreign substance adheres to the piezoelectric vibrating piece 22, the inherent frequency of vibration of the piezoelectric vibrating piece 22 may be lost. Further, since the foreign matter is a metal, it may be electrically short-circuited when it comes into contact with both the package body 48 and the piezoelectric vibrating piece 22.

  Here, FIG. 11 shows a partially enlarged piezoelectric vibrator 92 of the comparative example. In the comparative example, the package body 48 is not provided with the thick portion 78 of the present embodiment. It is. A gap GP is generated between the package body 48 and the closing plate 50.

  In the piezoelectric vibrator 92 of the comparative example, there is a possibility that foreign matter generated when the closing plate 50 is welded to the package main body 48 proceeds to the accommodating portion 46 through the gap GP.

  On the other hand, in the present embodiment, the package body 48 is provided with a thick portion 78, and the corner portions 68AC, 68AD, 68BC, and 68BD of the frame portion 68 are thick toward the housing portion 46. The foreign matter generated when the closing plate 50 is welded to the package body 48 may travel from the gap GP between the package body 48 and the closing plate 50 to the accommodating portion 46 as described above. Or, as the length increases, the foreign matter is less likely to travel to the accommodating portion 46. That is, in this embodiment, even if a foreign object tries to advance from the welded part 74 to the accommodating part 46, the thick part 78 has a long region (foreign substance passage) for the foreign substance to move to the accommodating part. It is suppressed that a foreign material enters the storage portion 46. In addition, by suppressing the entry of foreign matter into the housing portion 46, it is possible to suppress a shift in the frequency of vibration of the piezoelectric vibrating piece 22 and an electrical short circuit between the piezoelectric vibrating piece 22 and the package body 48.

  Next, the operation of this embodiment will be described.

  In the present embodiment, by applying a predetermined voltage from the external electrode 66 to the piezoelectric vibrating piece 22 through the through electrode 64 and the conductive adhesive 62, the pair of vibrating arm portions 26 vibrate in the piezoelectric vibrating piece 22. . Then, this vibration is converted into an electric signal and taken out of the piezoelectric vibrator 42.

  In the present embodiment, as described above, the package body 48 is provided with the thick portion 78. The structure is such that foreign matter generated when the closing plate 50 is welded to the package main body 48 is difficult to travel to the housing portion 46. Since the adhesion of foreign matter to the piezoelectric vibrating piece 22 is suppressed, the frequency deviation of the vibration of the piezoelectric vibrating piece 22 is also suppressed. In addition, electrical short-circuiting between the piezoelectric vibrating piece 22 and the package body 48 due to foreign matter is suppressed, and a highly reliable piezoelectric vibrator 42 is obtained.

  In order to prevent foreign matter generated when the closing plate 50 is welded to the package body 48 from entering the housing portion 46, it is conceivable to lower the applied voltage during welding. However, if the applied voltage is lowered, the welding strength may also be reduced. In the present embodiment, it is not necessary to reduce the applied voltage during welding in order to prevent foreign matter generated during welding from entering the housing portion 46. That is, by increasing the applied voltage at the time of welding, the closing plate 50 can be reliably welded to the package body 48 and the adhesion between the closing plate 50 and the package body 48 can be maintained firmly.

  FIG. 12 shows a piezoelectric vibrator 82 according to a modification of the first embodiment. The thick portion 78 may be linear like the piezoelectric vibrator 82 of this modification. In the example shown in FIG. 3, the thick portion 78 is curved convexly toward the housing portion 46. By curving the thick wall portion 78 in this way, a portion that substantially blocks the progression of foreign matter when the corner portions 50AC, 50AD, 50BC, 50BD of the closing plate 50 are used as a reference (with the thick wall portion 78 and A narrow gap GP between the closing plate 50 and the closing plate 50) can be secured long on the housing portion 46 side. Thereby, the effect which interrupts | blocks the advance of the foreign material to the accommodating part 46 becomes high.

  The frame portion 68 and the thick portion 78 are flush with each other on the side facing the closing plate 50. In other words, no step is generated between the frame portion 68 and the thick portion 78 on the side facing the closing plate 50. On the other hand, for example, as shown by the alternate long and short dash line in FIG. 10, in the structure in which the thick portion 78 is lower than the frame portion 68, the gap GP between the thick portion 78 and the closing plate 50 becomes wide. Therefore, in the structure shown by the one-dot chain line in FIG. 10, the effect of suppressing the progression of the foreign matter to the accommodating portion 46 is small, but in this embodiment, the gap GP can be kept narrow, so that the foreign matter proceeds to the accommodating portion 46. It can be reliably suppressed.

  The vibrating arm portion 26 is not in contact with the thick portion 78 and is not in contact with the package 44. Since the vibration of the vibrating arm portion 26 is not transmitted to the package 44, the piezoelectric vibrator 42 of this embodiment has good vibration characteristics.

  Next, a second embodiment will be described. In the piezoelectric vibrator 84 of the second embodiment, the same elements, members, and the like as those of the piezoelectric vibrator 42 of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In the second embodiment, the structure of the piezoelectric vibrating piece is the same as that of the first embodiment, and a detailed description thereof will be omitted.

  As shown in FIGS. 13 to 15, in the piezoelectric vibrator 84 of the second embodiment, a groove portion 86 is provided in the frame portion 68 instead of the thick portion 78 of the first embodiment. The groove part 86 is an example of the blocking part 76.

  The groove portion 86 is provided corresponding to each of the four corner portions 68AC, 68AD, 68BC, and 68BD of the frame portion 68. The position of the groove portion 86 in plan view is closer to the housing portion 46 than each of the four corners 50AC, 50AD, 50BC, and 50BD of the closing plate 50, in other words, closer to the inside of the closing plate 50 in plan view. Furthermore, as shown in FIG. 16, the position of the groove 86 is a position that does not overlap the weld 74 in plan view. The depth of the groove 86 may be a depth that does not penetrate the seal frame 56 or may penetrate the seal frame 56.

  Each groove portion 86 includes a first portion 86F extending in a direction along the long side 68LA or the long side 68LB in the frame portion 68, and a second portion 86S extending in a direction along the short side 68SC or the short side 68SD. Is a shape that forms a right angle in the central portion 86C.

  Also in the second embodiment, the method for manufacturing the piezoelectric vibrator 84 can be performed by the same steps as the method for manufacturing the piezoelectric vibrator 42 of the first embodiment.

  In particular, in the second embodiment, a groove 86 is provided in the package body 48, and a space SP (gap) is generated between the groove 86 and the closing plate 50. And the wall part 88 is located by the frame part 68 at the accommodating part 46 side rather than the space SP. The groove portion 86 can be formed by pressing, for example, when a ceramic green sheet forming the seal frame 56 is punched out.

  In the second embodiment, even if a foreign matter generated when the closing plate 50 is welded to the package body 48 is going to travel from the welded portion 74 to the accommodating portion 46, the foreign matter enters the groove portion 86. The wall portion 88 suppresses foreign matter from entering the housing portion 46. By suppressing the entry of foreign matter into the housing portion 46, it is possible to suppress a shift in the frequency of vibration of the piezoelectric vibrating piece 22 and an electrical short circuit between the piezoelectric vibrating piece 22 and the package body 48.

  In particular, as shown in FIG. 14, the groove 86 has a shape having a first portion 86F along the long side 68LA or the long side 68LB of the frame portion 68 and a second portion 86S along the short side 68SC or the short side 68SD. is there. Therefore, for example, compared with the shape of the groove portion having only the first portion 86F or only the second portion 86S, the effect of suppressing foreign matter from entering the housing portion 46 is high.

  Next, a third embodiment will be described. In the piezoelectric vibrator 90 of the third embodiment, the same elements, members, and the like as those of the piezoelectric vibrator 42 of the first embodiment or the piezoelectric vibrator 84 of the second embodiment are denoted by the same reference numerals, and detailed description will be given. Omitted. Also in the third embodiment, since the structure of the piezoelectric vibrating piece is the same as that of the first embodiment, detailed description thereof is omitted.

  As shown in FIGS. 17 to 19, in the piezoelectric vibrator 90 of the third embodiment, the frame portion 68 is provided with both the thick portion 78 of the first embodiment and the groove portion 86 of the second embodiment. Yes.

  Therefore, in the third embodiment, the entry of the foreign matter generated when the closing plate 50 is welded to the package body 48 into the accommodating portion 46 is suppressed by both the thick portion 78 and the groove portion 86.

  In the third embodiment, the strength of the frame portion 68 is increased by providing the thick portion 78, and the wall portion 88 is suppressed from being deformed toward the accommodating portion 46 side.

  In each said embodiment, although the thick part 78 and the groove part 86 were illustrated as the interruption | blocking part 76, the interruption | blocking part 76 is not limited to these. For example, a structure may be employed in which a wall is formed from the bottom 69 of the package body 48 toward the closing plate 50, and the progress of foreign matter to the accommodating portion 46 is suppressed by this wall (foreign matter hits the wall).

  The blocking portion 76 may be provided in correspondence with, for example, the two corner portions 68AC, 68AD and the corner portions 68BC, 68BD instead of the four corner portions 68AC, 68AD, 68BC, 68BD of the frame portion 68. However, in the process of actually welding the closing plate 50 to the package body 48, the welding electrode 80 shown in FIG. 9 is moved along the long sides 68LA and 68LB, and the voltage is increased at both the initial and final stages of the movement. There are many. Therefore, if the blocking portions 76 are provided in correspondence with the two end portions of the two long sides 68LA and LB, that is, the four corner portions 68AC, 68AD, 68BC, and 68BD of the frame portion 68, the foreign matter in the storage portion 46 is prevented. The effect of suppressing the progress is high.

  The piezoelectric vibrators 42, 82, and 90 of the above embodiments can be mounted on various devices.

  For example, FIG. 20 shows the oscillator 100. The oscillator 100 uses the piezoelectric vibrator 42 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. An integrated circuit 101 for an oscillator is mounted on the substrate 103, and a piezoelectric vibrator 42 is mounted in the vicinity of the integrated circuit 101. The electronic component 102, the integrated circuit 101, and the piezoelectric vibrator 42 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 42, the piezoelectric vibrating piece 22 in the piezoelectric vibrator 42 vibrates. This vibration is converted into an electric signal by the piezoelectric characteristics of the piezoelectric vibrating piece 22 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 42 functions as an oscillator.

  In addition, by selectively setting the configuration of the integrated circuit 101, for example, an RTC (real-time clock) module or the like as required, the operation date and time of the device and 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.

  Since such an oscillator 100 includes the piezoelectric vibrator according to any one of the first to third embodiments, it is possible to obtain an oscillator 100 with excellent vibration characteristics and excellent reliability.

  Next, FIG. 21 shows a portable information device 110 as an example of an electronic device. The portable information device 110 is, for example, a cellular phone, and includes a display unit (display) 115 that displays predetermined information. In addition, it is possible to communicate with an external base station or communication base unit. Furthermore, it is possible to transmit and input voice to the user through a speaker or a microphone.

  The portable information device 110 includes a piezoelectric vibrator 42 and a power supply unit 111 for supplying power. The power supply unit 111 includes, for example, a lithium secondary battery. A control unit 112, a timing unit 113, a communication unit 114, a display unit 115, and a voltage detection unit 116 are connected to the power supply unit 111 as functional units.

  The control unit 112 performs various controls in the portable information device 110. The clock unit 113 counts time and the like. Communication unit 114 communicates with the outside of portable information device 110. Display unit 115 displays various information in portable information device 110. The voltage detection unit 116 detects the voltage of each functional unit in the portable information device 110, and power is supplied to each functional unit by the power supply unit 111.

  More specifically, 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 is used as a read-only memory (ROM) in which a program is written in advance, a central pricing unit (CPU) that reads and executes the program written in the ROM, and a work area of the CPU. And Random Access Memory (RAM).

  The timer unit 113 includes an integrated circuit that includes an oscillation circuit, a register circuit, a counter circuit, an interface circuit, and the like, and the piezoelectric vibrator 42. When a voltage is applied to the piezoelectric vibrator 42, the piezoelectric vibrating piece 22 vibrates, and this vibration is converted into an electric signal by the piezoelectric characteristics of the crystal and 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 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, 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 ringtones and received voices and collects voices.

  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 audio processing unit 118 to the ringing tone generating unit 123 at the time of an incoming call, so that the ringing tone generated in the ringing tone generating unit 123 is voiced through the amplifying unit 120. The data is output to the input / output unit 121. The call control memory unit 124 stores a program related to communication incoming / outgoing call control. The telephone number input unit 122 includes, for example, number keys from 0 to 9 and other keys, and the user can input the telephone number of the call destination by pressing these keys.

  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.

  Since the portable information device 110 includes the piezoelectric vibrator according to any one of the first to third embodiments, the portable information device 110 having excellent reliability can be obtained by the excellent vibration characteristics of the piezoelectric vibrator. it can.

  Next, a radio timepiece 130 is shown in FIG. The radio timepiece 130 includes a piezoelectric vibrator 42 that is electrically connected to the filter unit 131. A standard radio wave including clock information is received and the time is automatically corrected and displayed.

  The radio timepiece 130 includes a filter unit 131, an antenna 132, an amplifier 133, a detection rectification circuit 134, a waveform shaping circuit 135, a CPU 136, a Real Time Clock (RCT) 137, and crystal units 138 and 139.

  The antenna 132 receives a standard radio wave, for example, a long wave of 40 kHz or 60 kHz in Japan. The received standard radio wave is amplified by the amplifier 133 and filtered and tuned by the filter unit 131 having the plurality of piezoelectric vibrators 42. The piezoelectric vibrator 42 used for the radio timepiece 130 includes crystal vibrator portions 138 and 139 each having a resonance frequency of 40 kHz or 60 kHz.

  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 year, accumulated date, day of the week, and time at the time. The read information is reflected in the RTC 137, and accurate time information is displayed.

  Since the radio timepiece 130 also includes the piezoelectric vibrator according to any one of the first to third embodiments, the radio timepiece 130 having excellent reliability can be obtained by the excellent vibration characteristics of the piezoelectric vibrator. .

22 Piezoelectric vibrating piece 42 Piezoelectric vibrator 44 Package 44H Open surface 46 Housing portion 48 Package body 50 Closing plate 50AC, 50AD, 50BC, 50BD Closing plate corner 52 Package plate 54 Package frame 56 Seal frame 68 Frame portion 68AC, 68AD, 68BC, 68BD Frame corner 69 Bottom 76 Blocking portion 78 Thick portion 80 Welding electrode 82 Piezoelectric vibrator 84 Piezoelectric vibrator 86 Groove 86F First part 86S Second part 90 Center angle 90 Piezoelectric vibrator 92 Piezoelectric vibrator 100 Oscillator 110 Portable information device 130 Radio clock

Claims (9)

A piezoelectric vibrating piece that vibrates at a predetermined frequency by applying a voltage;
A box body having a rectangular parallelepiped shape having a frame portion and a bottom portion, and a package main body including an accommodating portion in which the piezoelectric vibrating piece is accommodated;
A closing plate that is welded to the package body to close the housing portion;
A blocking portion that blocks the progress of foreign matter from the corner side of the frame portion to the housing portion;
A piezoelectric vibrator having:   2. The piezoelectric vibrator according to claim 1, wherein the blocking portion includes a thick portion that thickens a corner portion of the frame portion toward the housing portion in a plan view of the package body.   The piezoelectric vibrator according to claim 2, wherein the thick-walled portion is convexly curved toward the housing portion in the plan view.   4. The piezoelectric vibrator according to claim 2, wherein the frame part and the thick part are flush with each other on the side facing the blocking plate. 5.   The said interruption | blocking part contains the groove part formed in the said frame part by the side of the said accommodating part rather than the corner | angular part of the said obstruction board in the planar view of the said package main body with a clearance gap from the said obstruction board. 5. The piezoelectric vibrator according to any one of 4 above.   The piezoelectric vibrator according to claim 5, wherein the groove has two sides in a direction along the frame in the plan view.   An oscillator comprising the piezoelectric vibrator according to any one of claims 1 to 6, wherein the piezoelectric vibrator is electrically connected to an integrated circuit as an oscillator.   An electronic device comprising the piezoelectric vibrator according to any one of claims 1 to 6, wherein the piezoelectric vibrator is electrically connected to a time measuring unit.   A radio timepiece comprising the piezoelectric vibrator according to any one of claims 1 to 6, wherein the piezoelectric vibrator is electrically connected to a filter portion.