Tuning fork-type piezoelectric vibration device

Abstract

To provide a tuning fork-type piezoelectric vibration device with a larger resistance to impact.SOLUTION: A tuning fork-type piezoelectric vibrator 1 is equipped with at least one tuning fork-type piezoelectric vibration piece 2 in a container 3. The tuning fork-type piezoelectric vibration piece 2 includes: a base part 20; a pair of vibration arm parts 21, 22 extending in a first direction from one end side of the base part 20; a supporting arm part 23 extending in the first direction from between the pair of vibration arm parts 21, 22; and wide parts 211, 221 formed in the tip ends in the first direction of the pair of vibration arm parts 21, 22. The supporting arm part 23 has metal bumps 7a and 7b joined to the container 3. The container 3 contains equipped pads 6a and 6b joined to the metal bumps 7a, 7b and a step part 31 with the equipped pads 6a and 6b in the upper surface. The step part 31 is not arranged between the pair of wide parts 211, 221.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a tuning-fork type piezoelectric vibrating device 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 vibrating devices in which the concave portion is hermetically sealed with a lid.

[0003] As such a tuning fork type piezoelectric vibration device, a tuning fork type crystal unit is disclosed that incorporates a three-arm tuning fork type crystal piece having first and second vibrating arms extending parallel to each other from a base and a support arm extending from the base between the vibrating arms (see Patent Document 1). Such a three-arm tuning fork type crystal piece can be made smaller than a tuning fork type crystal piece that has support arms on the left and right of the vibrating arms. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication 2019-165348 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in a configuration having a support arm extending from a base between the vibrating arms as described in Patent Document 1, when an impact is applied to the tuning fork type quartz crystal vibrator (tuning fork type piezoelectric vibrator), the vibrating arm of the tuning fork type quartz crystal vibrating piece (tuning fork type piezoelectric vibrating piece) may come into contact with the container while tilting with the joint of the support arm as a fulcrum, and the vibration characteristics of the tuning fork type piezoelectric vibrating piece may change. That is, even when using a tuning fork type piezoelectric vibrating piece having a shape having a support arm extending from a base between the vibrating arms as described in Patent Document 1, for example, a tuning fork type piezoelectric vibrator (tuning fork type piezoelectric vibrating device) with higher impact resistance has been desired.

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

[0007] The present invention is a tuning fork-type piezoelectric vibration device having at least a tuning fork-type piezoelectric vibration piece mounted inside a container, wherein the tuning fork-type piezoelectric vibration piece comprises a base, a pair of vibrating arms extending in a first direction from one end side of the base, and a support arm extending in the first direction from between the pair of vibrating arms, the vibrating arms have a wide portion at an end on the first direction side, the support arm has a joint joined to the container, the container has a mounting portion joined to the joint and a step portion having the mounting portion on its upper surface inside, and the step portion is not positioned between the wide portions of each of the pair of vibrating arms when viewed in a plan view, which is a tuning fork-type piezoelectric vibration device.

[0008] That is, the tuning fork type piezoelectric vibration device of the present invention is configured such that the mounted tuning fork type piezoelectric vibration piece has a vibrating arm portion extending in a first direction and a wide portion provided at the tip of the vibrating arm portion, the container has a step portion inside with the mounting portion on its upper surface, and the step portion is not disposed between the wide portions in a plan view. With such a configuration, it is possible to ensure a sufficient distance between the container and the vibrating arm portion, and to improve the impact resistance of the tuning fork type piezoelectric vibration device. Also, even if the tuning fork type piezoelectric vibration piece is misaligned in the left-right direction due to mounting misalignment, it is possible to prevent the wide portion or the vibrating arm portion from coming into contact with the container due to bending vibration of the vibrating arm portion or vibration due to impact.

[0009] The support arm may have a support arm width as a size in the width direction, and be disposed at a predetermined distance from each of the pair of vibrating arms in the width direction, and the step may have a step width as a size in the width direction, and the step width may be equal to or larger than the support arm width and equal to or smaller than the sum of the support arm width and the separation distance. With such a configuration, the step width can be sufficiently secured relative to the support arm width. In other words, even if the tuning fork type piezoelectric vibrating piece is misaligned in the width direction of the support arm due to mounting misalignment, the bonding area can be sufficiently secured, and the reliability of the tuning fork type piezoelectric vibrating device can be improved.

[0010] The joint portion and the mounting portion may be joined by a bump made of metal. With such a configuration, the joining strength between the container and the tuning-fork type piezoelectric vibrating piece can be improved compared to joining by adhesive. Furthermore, by improving the joining strength, when the piezoelectric vibrating device receives an external impact, it is possible to prevent the vibrating arm portion of the mounted tuning-fork type piezoelectric vibrating piece from coming into contact with the container, resulting in damage or changes in vibration characteristics. Effect of the Invention

[0011] According to the present invention, a tuning-fork type piezoelectric vibration device having higher impact resistance can be provided. [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] 2 is a cross-sectional view taken along the line AA of the tuning-fork-type piezoelectric vibrator in the state where it is hermetically sealed with a lid in FIG. 1. [Diagram 3] 1 is a schematic plan view of one main surface of a tuning-fork type piezoelectric vibrating piece according to a first embodiment. [Figure 4] FIG. 2 is an enlarged plan view of the vicinity of a joint of the tuning fork-type piezoelectric vibrator in FIG. 1. [Diagram 5] FIG. 13 is a top view of a tuning-fork type piezoelectric vibrator according to another embodiment. [Figure 6] 6 is a CC cross-sectional view of the tuning-fork-type piezoelectric vibrator in the state where it is hermetically sealed with the lid in FIG. 5. [Figure 7] FIG. 13 is a top view of a tuning-fork type piezoelectric vibrator according to still 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] 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 the first embodiment (present 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 tuning-fork type 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 stepped portion 31 forms an edge 32 as an end face in a direction protruding with respect to the concave portion 5 in plan view. Further, the stepped portion 31 in the present embodiment is formed near the center of the short side in plan view of the container 3 and protrudes with respect to the concave portion 5, and has a substantially rectangular shape with a uniform width having the protruding direction as the longitudinal direction in plan view. Further, the stepped portion 31 is provided with two mounting pads 6a and 6b that are electrically joined to the crystal oscillator 2 on the upper surface. The mounting pads 6a and 6b are formed with a gap therebetween, and are connected to the metal bumps 7a and 7b of the tuning fork type piezoelectric vibrator 2 by bump bonding, respectively. That is, the mounting pads 6a and 6b correspond to the mounting portions in the present invention. In the present embodiment, the mounting pads 6a and 6b are arranged side by side in the longitudinal direction of the long side in plan view of the container 3 (the longitudinal direction of the stepped portion 31), but the width of the stepped portion 31 is formed to be sufficiently large and arranged side by side in the short side direction in plan view of the container 3. Also, the two mounting pads 6a and 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 via internal wiring and vias (not shown).

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

[0020] The lid 4 can be, for example, a rectangular metal lid body made of kovar as a base. Also, for example, in the lid 4, a brazing material made of metal can be formed in a circumferential shape on the nickel plating layer on the outer peripheral portion on the joint surface side with the container 3. Further, the joint between the lid 4 and the container 3 can be brazing or seam welding.

[0021] FIG. 3 is a schematic plan view of one main surface side of the tuning fork type piezoelectric vibrator 2 according to an embodiment of the present invention. 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, 22 formed side by side from one end side of the base 20 and protruding (extending) in the Y direction (first direction), and a support arm 23 formed protruding in the Y direction (the same direction as the vibrating arms 21, 22) from between the pair of vibrating arms 21, 22 at one end side of the base 20. Therefore, the quartz crystal vibrating piece 2 is a tuning fork-shaped piezoelectric vibrating piece having a tuning fork shape in a plan view, and is formed into a three-arm shape by the support arm 23 extending in the same direction as the longitudinal vibrating arms 21, 22 and the pair of vibrating arms 21, 22. In this embodiment, the vibrating arms 21, 22 and the support arm 23 are formed to extend in the +Y direction, but may be formed to extend in the -Y direction.

[0023] The shape of the quartz crystal vibrating piece 2 of this embodiment (the vibrating arms 21, 22, base 20, and support arms 23 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 supporting arm 23. The side of the base 20 is formed to be gradually narrower from the vibrating arms 21, 22 side to the other end side. The base 20 may have one or more through holes penetrating in the Z direction. Such a configuration having through holes can ensure the conduction of the extraction electrodes described later. In addition, the mechanical vibration of the tuning fork vibrating arm part during operation can be efficiently attenuated and the propagation of the vibration to the supporting arm 23 can be suppressed, thereby reducing acoustic leakage and lowering the series resonance resistance (CI).

[0025] The pair of vibrating arms 21, 22 are formed continuously from the base 20. The pair of vibrating arms 21, 22 are formed with narrow parts 214, 224 that are gradually narrower from the base 20, long parts 215, 225 that are formed continuously from the narrow parts 214, 224 and have a uniform width, wide parts 212, 222 that are further formed continuously from the long parts 215, 225 and gradually widen toward the tip side, and wide parts 211, 221 (weight parts) that are further formed continuously from the wide parts 212, 222 and are wider than the width of the long parts 215, 225 (the arm dimension in the second direction of the long parts 215, 225). That is, the wide parts 211, 221 form the tip parts of the vibrating arms 21, 22 in the second direction (X direction). The corners on the tip side of each of the wide portions 211, 221 are chamfered. The vibrating arms 21, 22 have a pair of main surfaces facing each other in the Z direction and a pair of side surfaces facing each other in the X direction.

[0026] A long groove is formed on the main surface 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 surface of each 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 at the boundary between the long portions 215, 225 and the widened portions 212, 222. That is, all the long grooves have a longitudinal direction along the direction in which the vibrating arms 21, 22 protrude (first direction, Y direction) and a width direction along the direction in which the vibrating arms 21, 22 are arranged side by side (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 supporting arm 23 is formed so as to protrude in the Y direction from one end side of the base 20 (the side from which the vibrating arms 21 and 22 protrude). That is, the supporting arm 23 is formed so as to protrude in the first direction from one end side of the base 20. It is preferable that the supporting arm 23 is disposed at equal intervals with respect to each of the vibrating arms 21 and 22. That is, it is preferable that the supporting arm 23 is formed so as to protrude from the exact center of the protruding positions of the two vibrating arms 21 and 22 on the base 20. Moreover, the supporting arm 23 in this embodiment has a substantially rectangular shape having a uniform width with the first direction as the longitudinal direction.

[0028] The support arm 23 has a metal bump 7b on the back side near the tip end extending in the longitudinal direction (first direction), and a metal bump 7a on the back side on the base 20 side as viewed from the metal bump 7b. 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 portion in the present invention, and the bonding portion is composed of the metal bump. In this embodiment, the metal bump 7b is provided at the tip end of the support arm 23, but is not limited thereto. For example, the metal bump 7b may be provided near the center of the support arm 23 in the first direction, or may be provided at a position further toward the base 20 side from the center. Also, as long as the multiple metal bumps are bonded to both of the mounting pads 6a, 6b (mounting portions) of the container 3, the positions, shapes, and number of the metal bumps on the support arm 23 are not particularly limited. That is, the metal bumps 7a, 7b in this embodiment are elliptical and of the same size, but the shapes of the metal bumps 7a, 7b are not particularly limited and may be of various shapes, and the metal bumps 7a and 7b may be different in size or shape from each other. Also, in this embodiment, the support arm 23 is configured to have two metal bumps 7a, 7b, but it is sufficient that the support arm 23 has multiple (two different polarity) metal bumps, and may have three or more metal bumps.

[0029] 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 via the base 20 and the support arm 23, and the extraction electrode drawn from the second excitation electrode is connected to the metal bump 7a via the surface of the base 20 and the support arm 23. Note that illustration of each electrode pattern is omitted in each drawing.

[0030] FIG. 4 is an enlarged plan view of the vicinity of the joint of tuning-fork type 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.

[0031] At this time, the wide portions 211, 221 of the quartz crystal vibrating piece 2 and the step portion 31 of the container 3 have a specific positional relationship in plan view. More specifically, in plan view, the step portion 31 is not disposed on the wide portions 211, 221 of the quartz crystal vibrating piece 2 in the second direction. That is, the step portion 31 is not disposed between the pair of wide portions 211, 221. At this time, the edge 32 of the step portion 31 extending from the base 20 side is disposed on the base 20 side of the boundary line BB between the widened portions 212, 222 and the wide portions 211, 221 in the second direction. Furthermore, it is preferable that the edge 32 of the step portion 31 is disposed on the base 20 side of the boundary line between the long portions 215, 225 and the wide portions 211, 221 in the second direction.

[0032] There is a specific relationship between the support arm width L3, which is the size of the support arm 23 of the quartz crystal vibrating piece 2 in the width direction (second direction), the separation interval L2, which is a predetermined interval in the second direction between the support arm 23 and the long parts 215, 225 of the vibrating arms 21, 22, and the step width L1, which is the size of the step 31 in the width direction (second direction). In detail, the step width L1 is equal to or larger than the support arm width L3 and equal to or smaller than the sum of the support arm width L3 and the separation interval L2. It is preferable that the step width L1 is larger than the support arm width L3. For example, when the protruding position of the support arm 23 on the base 20 is shifted in the second direction, that is, when the interval between the support arm 23 and the long part 215 and the interval between the support arm 23 and the long part 225 are different, the smaller interval can be set as the separation interval L2. Furthermore, in this embodiment, the distance in the second direction between the supporting arm 23 and the long portions 215, 225 of the vibrating arms 21, 22 is set as the separation distance L2, but the end points of the separation distance L2 are appropriately set according to the shapes of the supporting arm 23 and the vibrating arms 21, 22. That is, when the vibrating arms 21, 22 are in a state where they are flexurally vibrating due to the piezoelectric effect and when they are not vibrating, the points at which the supporting arm 23 and the vibrating arms 21, 22 are closest in the second direction are set as the end points of the separation distance L2.

[0033] With the above configuration, it is possible to provide a tuning-fork type piezoelectric vibrator 1 with higher shock resistance. The tuning fork type piezoelectric vibrator 1 (quartz crystal vibrator 1) of the present invention is configured such that, as viewed from the wide parts 211, 221 provided at the tips in the first direction of the vibrating arms 21, 22 of the mounted tuning fork type piezoelectric vibrating piece 2 (quartz crystal vibrating piece 2), the step part 31 of the container 3 is not arranged in a second direction perpendicular to the first direction in a plan view (the step part 31 is not arranged between the pair of wide parts 211, 221). With this configuration, the step part 31 can ensure a sufficient distance between the inner bottom surface of the container 3 and the vibrating arms 21, 22, thereby improving the impact resistance of the quartz crystal vibrator 1. In addition, even if the mounting deviation of the quartz crystal vibrating piece 2 occurs in the second direction, it is possible to prevent the wide parts 211, 221 of the vibrating arms 21, 22 from contacting with the step part 31 due to bending vibration of the vibrating arms 21, 22 or vibration due to impact. In other words, the wide portions 211, 221 are usually subjected to frequency adjustment by adjusting the thickness of the electrodes, etc., and contact with the step portion 31 may change the frequency characteristics of the quartz crystal vibrator 1. However, the configuration of the present invention makes it possible to prevent contact between the wide portions 211, 221 and the step portion 31, thereby improving the reliability of the frequency characteristics of the tuning fork-type piezoelectric vibrator 1.

[0034] In addition, in the crystal unit 1 of the present invention, the step width L1, the separation distance L2 between the step 31 and the vibrating arms 21 and 22, and the support arm width L3 are such that the step width L1 is equal to or larger than the support arm width L3 and is equal to or smaller than the sum of the support arm width L3 and the separation distance L2. With this configuration, the step width L1 can be sufficiently secured with respect to the support arm width L3. That is, even if the crystal unit 2 is misaligned in the left-right direction (second direction) due to mounting misalignment, the area bonded to the step 31 can be sufficiently secured, and the reliability of the crystal unit 1 can be improved. Furthermore, even if the crystal unit 2 is misaligned in the left-right direction (second direction) due to mounting misalignment, the vibrating arms 21 and 22 can be prevented from overlapping with the step 31 in a plan view. That is, it is possible to prevent the vibrating arms 21 and 22 from coming into contact with the step 31 due to an external impact, and the vibrating arms 21 and 22 from being damaged.

[0035] Furthermore, if the step width L1 is greater than the support arm width L3, the step width L1 can be more sufficiently secured relative to the support arm width L3. In other words, even if the quartz crystal vibrating piece 2 is misaligned in the left-right direction (second direction) due to mounting misalignment, the bonding area to the step 31 can be more sufficiently secured, and the reliability of the quartz crystal unit 1 can be further improved.

[0036] In addition, in the quartz crystal resonator 1 of this embodiment, the step portion 31 is formed so as to extend from the inner peripheral side surface of the container 3 in a plan view. With this configuration, even if an impact is applied to the quartz crystal resonator 1, the base portion 20 comes into contact with the step portion 31, and the vibrating arms 21, 22 do not come into contact with the container 3 and are not damaged. Furthermore, by the quartz crystal resonator piece 2 coming into contact with the end of the step portion 31, the contact portion serves as a fulcrum, and the principle of leverage works to prevent the quartz crystal resonator piece 2 from breaking. Furthermore, since the step portion 31 is formed continuously from the inner peripheral side surface of the container 3, the rigidity of the step portion 31 can be improved. In other words, when an impact is applied to the quartz crystal resonator 1, the step portion 31 is less likely to twist (distort), and the stress applied to the quartz crystal resonator piece 2 can be further reduced.

[0037] In addition, in the crystal unit 1 of the present invention, the support arm 23 of the crystal resonator 2 and the step 31 of the container 3 are bonded (bump bonded) by bumps made of metal plating. This configuration can improve the bonding strength between the container 3 and the crystal resonator 2 compared to bonding by adhesive. That is, when the crystal unit is subjected to an external shock, if the bonding is by adhesive, the mounted crystal resonator may tilt with the bonding part as a fulcrum, and the vibrating arm may come into contact with the container and be damaged. However, with the configuration of the present invention, the container and the crystal resonator can be firmly bonded, so that the crystal resonator 2 does not tilt with the metal bumps 7a and 7b as a fulcrum, and it is possible to prevent the vibrating arms 21 and 22 from coming into contact with the container 3 and being damaged or the vibration characteristics from changing. The adhesive referred to here is, for example, a conductive resin adhesive containing a conductive material such as a metal filler.

[0038] 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. 5 is a top view of a tuning-fork type piezoelectric vibrator 1 according to another embodiment, and FIG. 6 is a CC sectional view of the tuning-fork type piezoelectric vibrator 1 in FIG. 5 in a state where it is hermetically sealed with a lid. In this embodiment, the step portion 31 is configured to extend from the inner peripheral side surface of the container 3 in a plan view, but for example, it may be formed in an island shape that is not continuous with the inner peripheral side surface of the container 3. With such a configuration, it is possible to prevent the base 20 from coming into contact with the step portion 31 even if an impact is applied to the quartz crystal resonator 1.

[0039] FIG. 7 is a top view of a tuning-fork type piezoelectric vibrator 1 according to still another embodiment. In addition, in this embodiment, the step portion 31 is configured to extend from the inner peripheral side surface of the container 3 in a plan view. However, for example, the step portion 31 may be configured with a first step portion 31a that projects to the full width of the short side of the container 3 in a plan view, and a second step portion 31b that projects from the vicinity of the center of the edge of the first step portion 31a. In this case, it is preferable that the first step portion 31a and at least a part of the base portion 20 overlap in a plan view. With such a configuration, even if an impact is applied to the quartz crystal unit 1 and the base portion 20 comes into contact with the step portion 31, a larger contact area can be obtained, and damage to the base portion 20 can be prevented. Furthermore, with such an embodiment, the step portion 31 (first step portion 31a) can be formed continuously and larger on the inner peripheral side surface of the container 3. That is, the rigidity of the step portion 31 can be further improved, and when an impact is applied to the quartz crystal unit 1, twisting (distortion) of the step portion 31 is less likely to occur, and the stress applied to the quartz crystal vibrating piece 2 can be further reduced.

[0040] In addition, in this embodiment, as an example of a tuning fork-type piezoelectric vibration device, a tuning fork-type piezoelectric vibrator 1 in which a tuning fork-type piezoelectric vibrating piece 2 is sealed in a container 3 is used, but the device may also be, for example, a tuning fork-type piezoelectric vibration device equipped with an IC (integrated circuit) in addition to the tuning fork-type piezoelectric vibrating piece.

[0041] 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]

[0042] The tuning-fork type piezoelectric vibration device of the present invention can be used in the industry of manufacturing and selling piezoelectric vibration devices that incorporate a tuning-fork type piezoelectric vibration piece in a container. [Explanation of symbols]

[0043] 1...Tuning fork type piezoelectric vibrator 2...Piezoelectric vibrating piece 20…Base 21, 22... Vibrating arm 211, 221…Wide section 23...Support arm 3…Container 31...Double part 32...Edge 6a, 6b...Mounting pad 7a, 7b...Metal bumps

Claims

1. A tuning fork type piezoelectric vibrating device having at least a tuning fork type piezoelectric vibrating piece 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 support arm portion extending in the first direction from between the pair of vibrating arms, The vibrating arm portion is A wide portion is provided at a tip end on the first direction side, The support arm portion is a joint portion joined to the container, The container comprises: a mounting portion joined to the joint portion; a step portion having the mounting portion on an upper surface thereof, The step portion is not disposed between the respective wide portions of the pair of vibrating arms in a plan view. A tuning fork type piezoelectric vibration device.

2. The support arm portion is The support arm has a width as a size in a width direction, and is disposed at a predetermined distance from the pair of vibrating arms in the width direction, The step portion is The width direction has a step width, The width of the step is equal to or larger than the width of the support arm and is equal to or smaller than the sum of the width of the support arm and the separation distance.

2. The tuning fork type piezoelectric vibration device according to claim 1.

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

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

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