Tuning-fork type piezoelectric vibrator

Abstract

To provide a tuning-fork type piezoelectric vibrator of which the impact resistance is further improved.SOLUTION: There is provided a tuning-fork type piezoelectric vibrator 1. In the piezoelectric vibrator, one or more piezoelectric vibration pieces 2 are loaded inside of a container 3. The piezoelectric vibration piece 2 includes: a base part 20; a pair of vibration arm parts 21 and 22 extending in a first direction from the side of one end of the base part 20; a junction part 24 extending in a second direction that is orthogonal with the first direction; and a widened part 23 connecting the base part 20 with the junction part 24. The widened part 23 has a shape that is widened from the side of the base part 20 to the side of the junction part 24, and the junction part 24 includes metal bumps 7a and 7b which are joined to the container 3 at a plurality of positions separated in the second direction. The container 3 includes loading pads 6a and 6b, which are joined with the junction part 24, and a step part 31. The edge end 32 of the step part 31 is overlapped with the widened part 23 or the junction part 24 and not overlapped with a most narrowed part 231 and the metal bumps 7a and 7b in plan view.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a tuning-fork type piezoelectric vibrator equipped with a tuning-fork type piezoelectric vibrating piece in which a pair of vibrating arms vibrate in a flexural vibration mode. [Background technology]

[0002] Tuning-fork type piezoelectric vibrating pieces have been widely used as frequency generating sources for reference signals for clocks, etc. Such piezoelectric vibrating pieces are bonded and mounted inside the concave shape of an insulating base (container), and are used as surface-mount tuning-fork type piezoelectric vibrators in which the concave portion is hermetically sealed with a lid.

[0003] As such a tuning fork-type piezoelectric vibrator, a tuning fork-type piezoelectric vibrator has been disclosed in which a tuning fork-type piezoelectric vibrating piece having a joint that is approximately L-shaped when viewed from above is joined on the upper surface of a step provided in a container (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2013-232944 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in a configuration having a joint that is approximately L-shaped in plan view as described in Patent Document 1, a constriction is formed between the joint and the base, which is narrower than the joint and the base. Depending on the internal structure of the container, particularly the position of the step, the position of the constriction of the tuning fork type piezoelectric vibrating piece may overlap the position of the step of the container in plan view (see Patent Document 1, FIG. 23). In such a case, when an impact is applied to the tuning fork type piezoelectric vibrator, the constriction of the tuning fork type piezoelectric vibrating piece may come into contact with the end face (edge) of the step, and the tuning fork type piezoelectric vibrating piece may break at the constriction. That is, even when a tuning fork type piezoelectric vibrating piece having a constriction is used as described in Patent Document 1, for example, it has been desired to make a tuning fork type piezoelectric vibrator with higher impact resistance.

[0006] The present invention has been made in consideration of the above problems, and has an object to provide a tuning-fork type piezoelectric vibrator having higher impact resistance. [Means for solving the problem]

[0007] The present invention is a tuning fork-type piezoelectric vibrator having one or more tuning fork-type piezoelectric vibrating pieces mounted inside a container, wherein the tuning fork-type piezoelectric vibrating pieces include a base, a pair of vibrating arms extending from one end side of the base in a first direction, a widening portion protruding from the other end side of the base while widening in a direction opposite to the extension direction of the vibrating arms, and a joint portion formed continuously with the widening portion and protruding in at least one second direction perpendicular to the first direction from the widening portion, wherein the joint portion has a joint area joined to the container at a plurality of positions spaced apart in the second direction, and the container has inside a mounting area joined to the joint area and a step portion having the mounting area on its upper surface, and the end face of the step portion overlaps with the widening portion or the joint portion in a planar view, and does not overlap with the narrowest portion of the widening portion and the joint area at the joint portion.

[0008] That is, the tuning fork type piezoelectric vibrator of the present invention has a widening portion that protrudes while widening, and the end face of the step part of the container overlaps with the widening portion or the joint part in a plan view, but does not overlap with the narrowest part of the widening portion or the joint area of ​​the joint part. With this configuration, when an impact is applied to the tuning fork type piezoelectric vibrator from the outside, even if the tuning fork type piezoelectric vibrating piece mounted thereon bends in the vertical direction and the end face of the step part of the container comes into contact with the tuning fork type piezoelectric vibrating piece, the impact can be received by a stronger part of the tuning fork type piezoelectric vibrating piece, not by the narrowest part, which has a lower strength than the other parts, and the impact resistance of the tuning fork type piezoelectric vibrator can be improved. Also, the impact resistance of the tuning fork type piezoelectric vibrator can be improved without making a major design change to the container.

[0009] In addition, the widened portion may have a difference between the width at the boundary with the joint and the width at the narrowest portion, which is 100% wider than the narrowest portion, and the tuning-fork-type piezoelectric vibrating piece may overlap the end face of the step portion in a range from a position where the widened portion is 20% wider than the narrowest portion in the first direction to the joint region. With this configuration, the impact resistance of the tuning-fork-type piezoelectric vibrator can be further improved.

[0010] The joint and the step may be joined by a bump made of metal. With this configuration, the joining strength between the container and the tuning-fork type piezoelectric vibrating piece can be improved compared to joining by adhesive. Furthermore, although the improved joining strength makes it easier for external impacts to be transmitted to the tuning-fork type piezoelectric vibrating piece, the tuning-fork type piezoelectric vibrator of the present invention has improved impact resistance and can therefore prevent the tuning-fork type piezoelectric vibrating piece mounted thereon from breaking (breaking, destroying). Effect of the Invention

[0011] According to the present invention, it is possible to provide a tuning fork type piezoelectric vibrator having higher shock resistance. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a top view of a tuning-fork type piezoelectric vibrator according to a first embodiment. [Diagram 2] A cross-sectional view of the tuning fork-type piezoelectric vibrator in the state where it is hermetically sealed with a lid in FIG. [Diagram 3] 1 is a schematic plan view of one main surface side of a piezoelectric vibrating reed according to a first embodiment. [Figure 4] FIG. 4 is an enlarged plan view of the widened portion and the joint portion in FIG. 3 . [Diagram 5] 2 is an enlarged plan view of the vicinity of a widened portion and a joint of the piezoelectric vibrating piece in FIG. 1. [Figure 6] FIG. 11 is an enlarged plan view of a widened portion and a joint portion in another embodiment. [Figure 7] FIG. 13 is an enlarged plan view of a widened portion and a joint portion in yet another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this specification, the description of various electrodes formed on the piezoelectric vibrating piece (tuning fork type piezoelectric vibrating piece) is omitted. Also, the X-axis direction (X-direction) described in each drawing and this specification is the same as the X-axis direction of the crystal axis of the quartz crystal, the Y-axis direction (Y-direction) is the same as the Y-axis direction of the crystal axis of the quartz crystal (or the Y' direction tilted from the Y-axis by several degrees), and the Z-axis direction (Z-direction) is the same as the Z-axis direction of the crystal axis of the quartz crystal (or the Z' direction tilted from the Z-axis by several degrees).

[0014] <First embodiment> FIG. 1 is a top view of a tuning-fork type piezoelectric vibrator 1 according to the first embodiment, and FIG. 2 is a cross-sectional view taken along line AA of the tuning-fork type piezoelectric vibrator 1 in FIG. 1 in a state where it is hermetically sealed with a lid 4. As shown in FIG. In this specification, the depth direction in FIG. 1 is the bottom side of tuning fork type piezoelectric vibrator 1, and the front direction is the top side of tuning fork type piezoelectric vibrator 1, and the bottom and top are described.

[0015] The tuning fork type piezoelectric vibrator 1 (quartz crystal vibrator 1) in this embodiment is a surface mount type quartz crystal vibrator having a package structure of a substantially rectangular parallelepiped. The external dimensions of the quartz crystal vibrator 1 are not particularly limited, and may be any of various known dimensions depending on the application.

[0016] 2, in the quartz crystal resonator 1 according to this embodiment, a piezoelectric vibrating piece 2 (quartz crystal vibrating piece 2) is accommodated in a recess 5 of a container 3 made of an insulating material, and then a flat lid 4 is bonded to the open end of the container 3 so as to cover the recess 5, thereby hermetically sealing the quartz crystal vibrating piece 2 in the internal space. The container 3 and the lid 4 are bonded together via a sealing material (not shown).

[0017] The container 3 is a box-shaped body made of an insulating material mainly composed of ceramic such as alumina, and is formed by, for example, stacking three ceramic green sheets and sintering them together to form a bottom layer 3a, a middle layer 3b, and an upper layer 3c. In this embodiment, of the bottom layer 3a, the middle layer 3b, and the upper layer 3c, the rectangular frame-shaped middle layer 3b is stacked on the bottommost layer 3a, and the rectangular frame-shaped upper layer 3c is stacked on the middle layer 3b. Therefore, the container 3 has a rectangular recess 5 in plan view, with the upper surface of the bottom layer 3a as the bottom surface and the middle layer 3b and the upper layer 3c as the frame-shaped bank portion 30. The middle layer 3b protrudes toward the recess 5 on the upper surface of the bottom layer 3a, and a part of it forms a step portion 31 on which the quartz crystal vibrating piece 2 is mounted. A sealing material (not shown) is formed in a frame shape in a plan view on the upper surface 300 of the bank portion 30 (upper layer portion 3c).

[0018] The step 31 forms an edge 32 as an end face in a direction protruding from the recess 5 in a plan view. The step 31 also has two mounting pads 6a, 6b on the upper surface thereof that are conductively bonded to the crystal vibrating piece 2. The mounting pads 6a, 6b are formed in parallel with a gap between them, and are connected to the metal bumps 7a, 7b of the piezoelectric vibrating piece 2 by bump bonding, respectively. That is, the mounting pads 6a, 6b correspond to the mounting region in the present invention. The two mounting pads 6a, 6b have opposite polarities to each other, and are electrically connected to a plurality of external connection terminals 8 provided on the outer bottom surface of the container 3 through internal wiring and vias (not shown).

[0019] In this embodiment, the two mounting pads 6a and 6b are formed by laminating nickel and gold in this order on the upper surface of a tungsten metallization layer using a method such as plating. Note that molybdenum may be used as the metallization layer instead of tungsten.

[0020] The lid 4 may be, for example, a metal lid body having a rectangular shape in plan view and made of Kovar as a base. Also, for example, the lid 4 may be configured such that a brazing material made of metal is formed in a circumferential shape on a nickel-plated layer on the outer periphery of the joint surface side with the container 3. Furthermore, the joint between the lid 4 and the container 3 may be made by brazing or seam welding.

[0021] FIG. 3 is a schematic plan view of one main surface side of the piezoelectric vibrating piece 2 according to the embodiment of the present invention, and FIG. 4 is an enlarged plan view of the vicinity of the widened portion 23 and the joint portion 24 in FIG. For ease of explanation, of the two opposing main surfaces of the quartz crystal vibrating piece 2, the main surface that faces the mounting pads 6a, 6b when mounted on the container 3 will be referred to as the back surface, and the main surface opposite the back surface will be referred to as the front surface. That is, Fig. 3 is a plan view of the quartz crystal vibrating piece 2 as seen from the front surface side.

[0022] The quartz crystal vibrating piece 2 is a thin-plate-shaped quartz crystal Z plate having a thickness in the Z direction. The quartz crystal vibrating piece 2 includes a base 20, a pair of vibrating arms 21 and 22 formed side by side from one end of the base 20 and protruding (extending) in the Y direction (first direction), a widened portion 23 formed protruding in the -Y direction (opposite direction to the vibrating arms 21 and 22) from the other end opposite to the one end of the base 20, and a joint 24 formed continuously with the end of the widened portion 23 on the opposite side as viewed from the base 20 and protruding (extending) in the X direction (second direction) from the widened portion 23. Therefore, the quartz crystal vibrating piece 2 is a tuning fork-shaped piezoelectric vibrating piece having a tuning fork shape in a planar view, and the end opposite the vibrating arms 21 and 22 in the longitudinal direction is formed into a substantially L-shape in a planar view by the widened portion 23 and the joint 24. In this embodiment, the vibrating arms 21 and 22 are formed to extend in the +Y direction, but may be formed to extend in the -Y direction. Also, in this embodiment, the joint 24 is formed to extend in the +X direction, but may be formed to extend in the -X direction.

[0023] The shape of the quartz crystal vibrating piece 2 of this embodiment (the vibrating arms 21, 22, base 20, widened portion 23, and joint 24 that constitute the quartz crystal vibrating piece 2) is formed, for example, by wet etching a quartz crystal blank (not shown), which is a quartz crystal piece made of anisotropic material.

[0024] In this embodiment, the base 20 has a shape that is symmetrical (symmetrical in the X direction) in a plan view. The base 20 is formed to be wider (longer in the X direction) than the vibrating arms 21, 22 and the widened portion 23. The other end of the base 20 (near the boundary with the widened portion 23) is formed to be gradually narrower from the vibrating arms 21, 22 side to the widened portion 23 side. The base 20 may have one or more through holes penetrating in the Z direction. Such a configuration with through holes can ensure the conduction of the extraction electrodes described later. In addition, the mechanical vibration of the tuning fork vibrating arm portion during operation is efficiently attenuated and the propagation of the vibration to the joint 24 is suppressed, thereby reducing acoustic leakage and lowering the series resonance resistance (CI).

[0025] At the tip side of each of the pair of vibrating arms 21, 22, wide parts 211, 221 (weight parts) that are wider than the arm width (dimension of the arm in the second direction) of the vibrating arms 21, 22 are formed. The wide parts 211, 221 are integrally formed with the tip parts of the vibrating arms 21, 22 via the vibrating arm widening parts 212, 222 that gradually widen toward the second direction (X direction). That is, the vibrating arm widening parts 212, 222 and the wide parts 211, 221 are integrally formed with the vibrating arms 21, 22. Each corner of the tip side of the wide parts 211, 221 is chamfered. The vibrating arms 21, 22, the vibrating arm widening parts 212, 222, and the wide parts 211, 221 have a pair of main surfaces facing the Z direction and a pair of side surfaces facing the X direction.

[0026] A long groove is formed on the front and back main surfaces of each of the pair of vibrating arms 21 and 22 in order to further reduce the equivalent series resistance value (Crystal Impedance, CI value). More specifically, a long groove 213 is formed on the front main surface (front surface) of the vibrating arm 21, and a long groove (not shown) is formed on the back main surface (back surface) of the vibrating arm 21, so that the long grooves are formed to face each other. In addition, a long groove 223 is formed on the front main surface (front surface) of the vibrating arm 22, and a long groove (not shown) is formed on the back main surface (back surface) of the vibrating arm 22, so that the long grooves are formed to face each other. The long grooves 213 and 223 formed on the front and back surfaces of the vibrating arms 21 and 22 and the long groove (not shown) formed on the back surface are formed with a predetermined depth (length in the Z direction) and width (length in the X direction) on the front and back main surfaces of each of the vibrating arms 21 and 22. Moreover, one end of each long groove in the Y direction is formed up to the region of the base 20, and the other end is formed to be located on the root side of the vibrating arms 21, 22 with respect to the boundary between the vibrating arms 21, 22 and the vibrating arm widening parts 212, 222. That is, all the long grooves have a longitudinal direction along the protruding direction of the vibrating arms 21, 22 (first direction, Y direction) and a width direction along the juxtaposed direction of the vibrating arms 21, 22 (second direction, X direction). Moreover, an excitation electrode (not shown) described later is formed inside each long groove. Moreover, each long groove is formed by wet etching.

[0027] The widening portion 23 is formed so as to protrude in the -Y direction from the other end side of the base 20 (the side opposite to the protruding vibrating arms 21 and 22). That is, the widening portion 23 is formed so as to protrude in the first direction from the other end side of the base 20. The widening portion 23 is formed continuously with the joint portion 24 extending in the X direction from the end opposite to the base 20. The widening portion 23 has a shape in which the length (width) in the X direction gradually increases from the base 20 side to the joint portion 24 side. Therefore, the widening portion 23 has a narrowest part 231 (boundary line with the base 20) that is the narrowest (shortest length in the X direction) among the widening portion 23 and the joint portion 24 at the boundary with the base 20, and is formed so as to gradually increase in width from the narrowest part 231 toward the -Y direction. The widening portion 23 has a widest part 232 that is the widest in the widening portion 23 at the boundary with the joint portion 24. In this embodiment, of both end faces in the X direction of the widened portion 23, one end face 233 is formed in a linear shape (inclined), and the other end face 234 is formed in an R-shape. Moreover, both end faces are formed so as to face outward (so as to gradually move away from each other in the X direction) so that the width of the widened portion 23 gradually increases.

[0028] The joint 24 is formed continuously from the end of the widened portion 23 opposite to the end connected to the base 20. The length (width) of the joint 24 in the X direction is longer than that of the widened portion 23, and the joint 24 is formed so as to protrude in the X direction relative to the widened portion 23. The joint 24 in this embodiment is formed in a substantially rectangular shape with the X direction as the longitudinal direction, and the end face in the -X direction is formed continuously from one end face 233 of the widened portion 23 and parallel to the Y direction, and is formed to extend from the other end face 234 in the +X direction relative to the widened portion 23.

[0029] That is, the joint portion 24 is not directly connected to the base portion 20, but is connected via the widened portion 23. In other words, the widened portion 23 is formed so as to connect the base portion 20 and the joint portion 24.

[0030] In this embodiment, the bonding portion 24 has a metal bump 7a at one end in the X direction and a metal bump 7b at the other end. The metal bumps 7a and 7b are plated bumps formed by electrolytic plating. The metal bump 7a is bonded to the mounting pad 6a of the container 3 when the quartz crystal vibrating piece 2 is mounted on the container 3, and the metal bump 7b is bonded to the mounting pad 6b. That is, the metal bumps 7a and 7b correspond to the bonding region in the present invention. In this embodiment, the metal bumps 7a and 7b are provided at both ends of the bonding portion 24 in the X direction, respectively. However, the position, shape, and number of the metal bumps in the bonding portion 24 are not particularly limited as long as a plurality of metal bumps are bonded to both the mounting pads 6a and 6b (mounting regions) of the container 3. That is, the metal bumps 7a and 7b in this embodiment are elliptical and of the same size, but the shapes of the metal bumps 7a and 7b are not particularly limited and may be various shapes, and the metal bumps 7a and 7b may be different in size or shape from each other. In addition, in this embodiment, the joint 24 has two metal bumps 7a and 7b, but it is sufficient that the joint 24 has a plurality of (two different polarities) metal bumps, and may have three or more metal bumps. Furthermore, in this embodiment, the joint 24 has a metal bump 7a at one end in the X direction and a metal bump 7b at the other end, but one or both of the metal bumps 7a and 7b may be provided at a position more inward than the end. In this embodiment, the metal bump 7a may be provided in its entirety in the X direction within a range on the joint 24 obtained by shifting the range length of the width (along the X direction) of the narrowest part 231 in the Y direction as it is. In other words, the entire area of ​​the metal bump 7a is provided within a range on the extension of the narrowest part 231 of the bonding portion 24 in the Y direction.

[0031] In addition, the quartz crystal vibrating piece 2 is formed with a first excitation electrode and a second excitation electrode configured with different potentials, and an extraction electrode drawn from each of the first excitation electrode and the second excitation electrode via a wiring electrode. The first excitation electrode is formed on the front and back main surfaces including the inner circumferential surface of the long groove of one vibrating arm 21, and on the outer and inner surfaces of the other vibrating arm 22 via the wiring electrode. Similarly, the second excitation electrode is formed on the front and back main surfaces including the inner circumferential surface of the long groove of the other vibrating arm 22, and on the outer and inner surfaces of one vibrating arm 21 via the wiring electrode. The extraction electrode drawn from the first excitation electrode is connected to the metal bump 7b, and the extraction electrode drawn from the second excitation electrode is connected to the metal bump 7a. Note that in each drawing, illustration of each electrode pattern is omitted.

[0032] FIG. 5 is an enlarged plan view of the vicinity of the widened portion 23 and the joint portion 24 of the piezoelectric vibrating piece 2 in FIG. The quartz crystal vibrating piece 2 is mounted on the container 3 by bonding the metal bumps 7a, 7b of the quartz crystal vibrating piece 2 to the mounting pads 6a, 6b. The metal bumps 7a, 7b and the mounting pads 6a, 6b are conductively bonded to each other by FCB (Flip Chip Bonding). That is, the quartz crystal vibrating piece 2 is bonded and mounted on the container 3 by bumps made of metal plating (plated bumps). Note that in this embodiment, bump bonding is performed using plated bumps, but bump bonding using stud bumps may also be used.

[0033] At this time, the widened portion 23 or the joint portion 24 of the quartz crystal vibrating piece 2 and the edge 32 of the container 3 overlap to have a specific positional relationship in a plan view. More specifically, the overlapping position of the edge 32 and the quartz crystal vibrating piece 2 overlaps with the widened portion 23 or the joint portion 24 in a plan view, and is between the narrowest portion 231 of the widened portion 23 and the uppermost ends (ends on the base 20 side) of the metal bumps 7a, 7b in the Y direction. In other words, the edge 32 does not overlap with the narrowest portion 231 of the widened portion 23 and the metal bumps 7a, 7b of the joint portion 24 in a plan view.

[0034] In addition, in the widening portion 23 having a gradually widening shape, when the degree of widening at the narrowest part 231 is 0% and the degree of widening at the widest part 232 is 100%, if the edge 32 overlaps with the widening portion 23 in a planar view, it is preferable that the edge 32 overlaps with the widening portion 23 in a region where the degree of widening is 20% or more. More specifically, in the widening portion 23, it is preferable that the edge 32 overlaps with the widening portion 23 in a planar view at a position where the difference between the width at the widest part 232 and the width at the narrowest part 231 is 20% or more, assuming a 100% widening amount (widening degree). That is, in the widened portion 23, it is preferable that the piezoelectric vibrating piece 2 overlaps with the edge 32 in a plan view within a range from a position where the difference between the width at the widest portion 232 and the width at the narrowest portion 231 is 20% or more, assuming that the amount of width expansion (widening degree) is 100%, to the metal bumps 7a, 7b. Also, in the widened portion 23 having a shape that gradually widens, it is preferable that the edge 32 (end face) of the step portion 31 overlaps within a range from exactly halfway between the narrowest portion 231 and the widest portion 232 to the bonding region (metal bumps 7a, 7b). Note that the position where the widening degree is 20% in this embodiment is exactly halfway in the Y-axis direction of the widened portion 23. More specifically, the piezoelectric vibrating piece 2 in this embodiment has a width of 175 μm at the narrowest part 231, a width of 200 μm at the widest part 232, and a width of 180 μm at a position halfway in the Y direction of the widened part 23. Therefore, the difference (25 μm) between the widest part 232 (200 μm) and the narrowest part 231 (175 μm) is the 100% widening amount, and the position where the width is increased by 5 μm, which is 20% of 25 μm, that is, the position where the width is 180 μm (halfway in the Y direction of the widened part 23 in this embodiment) is the position where the width is increased by 20% compared to the narrowest part 231.

[0035] With the above configuration, it is possible to provide a tuning-fork type piezoelectric vibrator 1 with higher shock resistance. In the tuning fork type piezoelectric vibrator 1 (quartz crystal vibrator 1) of the present invention, the widened portion 23 connecting the base 20 and the joint 24 of the piezoelectric vibrating piece 2 (quartz crystal vibrating piece 2) has a shape that widens from the base 20 side to the joint 24 side, and the edge 32 (end face) of the step 31 of the container 3 overlaps the widened portion 23 or the joint 24 in a plan view, but does not overlap the narrowest part 231 that is the narrowest part of the joint 24 and the joint area (metal bumps 7a, 7b) of the joint 24. With this configuration, when an impact is applied to the tuning fork type piezoelectric vibrator 1 from the outside, even if the mounted piezoelectric vibrating piece 2 bends in the vertical direction and the edge 32 of the step 31 of the container 3 comes into contact with the piezoelectric vibrating piece 2, the impact can be received by a part of the piezoelectric vibrating piece that is stronger than the narrowest part 231, which has a lower strength than other parts, and the impact resistance of the tuning fork type piezoelectric vibrator 1 can be improved. Moreover, the impact resistance of the tuning-fork-type piezoelectric vibrator 1 can be improved without changing the design of the container.

[0036] Furthermore, by configuring the widened portion 23 to have a shape that widens from the base 20 side to the joint 24 side, the vibration can be reduced by the narrowest portion 231 and the reduced vibration can be further dispersed. That is, the mechanical vibration of the tuning fork vibrating arm portion during operation can be efficiently attenuated and the propagation of the vibration to the joint 24 can be suppressed. That is, when the quartz crystal vibrating piece 2 is held in the container 3, the acoustic leakage can be reduced and the series resonance resistance (CI) can be lowered.

[0037] Furthermore, because the edge 32 (end face) of the step 31 of the container 3 overlaps the widened portion 23 or the joint 24 in a plan view, the vibrating arms 21, 22 and base 20 of the quartz crystal vibrating piece 2 do not come into contact with the edge 32 of the step 31. Therefore, even if an impact is applied to the tuning-fork-type piezoelectric vibrator 1 (quartz crystal vibrator 1) and the quartz crystal vibrating piece 2 comes into contact with the edge 32, the base 20 or the vibrating arms 21, 22 will not be damaged, and the occurrence of frequency fluctuations (frequency shifts) can be suppressed.

[0038] In addition, in the crystal resonator 1 of the present invention, when the width of the widened portion 23 at the boundary with the joint portion 24 (widest portion 232) is set to be 100% wider than the narrowest portion 231, it is preferable that the edge 32 (end face) of the step portion 31 overlaps within a range from the point where the widened portion 23 is 20% wider to the joint region (metal bumps 7a, 7b). With this configuration, when the edge 32 of the step portion 31 of the container 3 comes into contact with the piezoelectric vibrating piece 2, it can be received at a portion having sufficient strength. More specifically, at a portion where the width is less than 20%, the strength of the widened portion 23 is insufficient, and impact resistance cannot be sufficiently improved. On the other hand, with the above-mentioned configuration, when the edge 32 comes into contact with the widened portion 23, it is possible for the widened portion 23 to receive the edge 32 at a position where the widened portion 23 is sufficiently wider. In other words, the impact resistance of the tuning fork-type piezoelectric resonator 1 can be further improved.

[0039] Furthermore, in the crystal resonator 1 of the present invention, it is preferable that in the widened portion 23, the edge 32 (end face) of the step 31 overlaps within a range from exactly halfway between the narrowest portion 231 and the widest portion 232 to the bonding region (metal bumps 7a, 7b). With this configuration, when the edge 32 of the step 31 of the container 3 comes into contact with the piezoelectric vibrating piece 2, the contact can be received at a portion having sufficient strength. In other words, the impact resistance of the tuning fork-type piezoelectric resonator 1 can be further improved.

[0040] In addition, in the crystal resonator 1 of the present invention, the bonding portion 24 of the crystal resonator piece 2 and the step portion 31 of the container 3 are bonded (bump bonded) by a bump made of metal. With this configuration, the bonding strength between the container 3 and the crystal resonator piece 2 can be improved compared to bonding by adhesive. In addition, while the improved bonding strength makes it easier for external impacts to be transmitted to the piezoelectric resonator piece 2, the crystal resonator 1 of the present invention has improved impact resistance, so that the crystal resonator piece 2 can be prevented from breaking (breaking, destruction). More specifically, the bump bonding shown in this embodiment can firmly bond the container and the crystal resonator piece. That is, it is a configuration that can bond electrically and mechanically firmly and stably. On the other hand, there is a concern that the buffer function of the bonding material is less likely to function compared to when an adhesive is used as a bonding material, and impact resistance is reduced. With the configuration of the present invention, it is possible to achieve a stable and strong bond electrically and mechanically, as well as improved impact resistance.

[0041] Furthermore, bump bonding is a bonding method in which a metal bump provided on a member to be bonded is brought into contact with a metallic mounting pad and ultrasonic waves are applied by a device to bond the metal bump to the mounting pad. At this time, a certain amount of space is required at least around the metal bump for the device that applies ultrasonic waves. If the edge 32 (end face) of the step portion 31 of the container 3 is configured to overlap the widened portion 23 or the bonding portion 24 in a plan view as in the present invention, the gap between the inner peripheral surface of the container 3 and the bonding portion 24 and the metal bumps 7a, 7b (bonding area) of the bonding portion 24 can be sufficiently widened, and sufficient space can be secured around the metal bumps 7a, 7b.

[0042] It should be noted that the present invention is not limited to the configurations of the above-described embodiments, and many other embodiments can be obtained. FIG. 6 is an enlarged plan view of the widened portion 23 and the joint portion 24 in another embodiment, and FIG. 7 is an enlarged plan view of the widened portion 23 and the joint portion 24 in yet another embodiment. For example, in the present embodiment, one end face 233 of the widening portion 23 in the X direction is formed in a linear shape (inclined) and the other end face 234 is formed in an R shape, but as long as the widening portion 23 is shaped to widen from the base portion 20 side to the joint portion 24 side, the shape of both end faces of the widening portion 23 in the X direction is not particularly limited. For example, both end faces of the one end face 233 and the other end face 234 may be formed in a linear shape (inclined) (see FIG. 6). Also, both end faces of the one end face 233 and the other end face 234 may be formed in an R shape (see FIG. 7). Even with such a configuration, the same effect as in this embodiment can be obtained.

[0043] The embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present invention is not interpreted solely by the above-described embodiments, but is defined by the claims. Also, all modifications within the scope and meaning equivalent to the claims are included. [Industrial Applicability]

[0044] The tuning-fork type piezoelectric vibrator of the present invention can be used in the industry of manufacturing and selling piezoelectric vibrators having a tuning-fork type piezoelectric vibrating piece mounted in a container. [Explanation of symbols]

[0045] 1...Tuning fork type piezoelectric vibrator 2...Piezoelectric vibrating piece 20…Base 21, 22... Vibrating arm 23…Wide section 231...Narrowest part 232…Widest part 24…Joint part 3…Container 31...Double part 32...Edge 6a, 6b...Mounting pad 7a, 7b...Metal bumps

Claims

1. A tuning fork type piezoelectric vibrator having one or more tuning fork type piezoelectric vibrating pieces mounted inside a container, The tuning fork type piezoelectric vibrating piece is A base and A pair of vibrating arms extending in a first direction from one end side of the base portion; a widened portion that protrudes from the other end side of the base portion while widening in a direction opposite to the extension direction of the vibrating arm portion; a joint portion formed continuously with the widening portion and protruding in at least one direction in a second direction perpendicular to the first direction with respect to the widening portion; The joint is a bonding region bonded to the container at a plurality of positions spaced apart in the second direction; The container comprises: a mounting area to be joined to the joining area; a step portion having the mounting area on an upper surface thereof, The end surface of the step portion is In a plan view, the widened portion overlaps with the widened portion or the joint portion, but does not overlap with a narrowest portion of the widened portion or the joint region of the joint portion. Tuning fork type piezoelectric vibrator.

2. In the widened portion, the difference between the width at the boundary with the joint and the width at the narrowest portion is set to a width that is 100% wider than the width of the narrowest portion, In a direction along the first direction, the tuning-fork-type piezoelectric vibrating piece overlaps with an end face of the step portion within a range from a position where the width of the widened portion is increased by 20% of the difference to the bonding region.

2. The tuning fork type piezoelectric vibrator according to claim 1.

3. The joint portion and the step portion are joined by a bump made of metal.

3. The tuning fork type piezoelectric vibrator according to claim 1 or 2.

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