Tuning fork type piezoelectric vibration device

Abstract

This invention provides a tuning fork-type piezoelectric vibration device that simultaneously prevents contact between the tuning fork-type piezoelectric vibrator and the inner wall surface of the package, as well as prevents short circuits. [Solution] The tuning fork piezoelectric oscillator 1 is configured such that the width L1 of the stepped portion 32 of the package 3 in the Y direction (first direction) is within 15% of the length L2 of the housing portion 31 in the first direction, the centerlines Q of the joining members 7a and 7b of the tuning fork piezoelectric vibrator 2 in the first direction are within 15% of the centerlines P of the mounting pads 6a and 6b in the first direction, and the end faces of the mounting pads 6a and 6b in the first direction do not overlap with the base portion 20 of the tuning fork piezoelectric vibrator 2 in a plan view.

Description

Technical Field

[0001] The present invention relates to a tuning fork type piezoelectric vibration device equipped with a tuning fork type piezoelectric vibration piece in which a pair of vibrating arms vibrate in a bending vibration mode.

Background Art

[0002] Among piezoelectric vibration devices, a tuning fork type piezoelectric vibration device equipped with a tuning fork type piezoelectric vibration piece has been widely used as a frequency generation source for reference signals such as in watches.

[0003] As such a tuning fork type piezoelectric vibration piece, a tuning fork type piezoelectric vibration piece having a holding portion (holding portion in the present invention) substantially L-shaped in plan view is disclosed (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the tuning fork type piezoelectric vibration piece having a holding portion substantially L-shaped in plan view as described in Patent Document 1, compared with a tuning fork type piezoelectric vibration piece having no holding portion, it has a longer shape in the longitudinal direction. Therefore, when mounted on a package, there is a risk that the tip of the vibrating arm may contact the inner wall surface of the package. On the other hand, if an attempt is made to adjust the mounting position of the tuning fork type piezoelectric vibration piece so that the vibrating arm does not contact the inner wall surface of the package, as shown in FIG. 6, the base portion 201 of the tuning fork type piezoelectric vibration piece 200 and the mounting pad 600 of the package will overlap in plan view. Depending on the inclination of the tuning fork type piezoelectric vibration piece 200 in the thickness direction during mounting, there is a risk that the wiring patterns 202 and 203 of different polarities provided on the base portion 201 may contact the mounting pad 600 and cause a short circuit.

[0006] The present invention has been made in view of the above problems, and aims to provide a tuning fork type piezoelectric vibration device that achieves both prevention of contact between the tuning fork type piezoelectric vibrator and the inner wall surface of the package and prevention of short circuits. [Means for solving the problem]

[0007] The present invention relates to a tuning fork type piezoelectric vibrator device comprising a tuning fork type piezoelectric vibrator and a package that houses the tuning fork type piezoelectric vibrator in an internal housing, wherein the tuning fork type piezoelectric vibrator comprises a base, a pair of vibrating arms extending in a first direction from one end of the base, a holding portion extending from the other end of the base in the opposite direction to the extension direction of the vibrating arms and protruding in at least one of a second direction perpendicular to the first direction, and at least the base comprises two metal wiring patterns that are opposite in polarity to each other, the holding portion has joints that are joined to the package via a joining member at a plurality of positions spaced apart in the second direction, and the package is The device is characterized in that the housing portion has a vibrating element mounting pad joined to the tuning fork type piezoelectric vibrating element, and a stepped portion having the vibrating element mounting pad on its upper surface, the width of the vibrating element mounting pad in the long-side direction of the housing portion is within 15% of the length of the housing portion in the long-side direction, the center line of the joining portion in the first direction is provided to be within 15% of the center line of the vibrating element mounting pad in the long-side direction of the housing portion in the first direction, and the end face of the vibrating element mounting pad in the long-side direction of the housing portion does not overlap with the base portion in a plan view.

[0008] In other words, the tuning fork type piezoelectric vibration device of the present invention is configured such that the width of the housing portion of the vibrating piece mounting pad of the package is within 15% of the length of the housing portion in the long side direction, the center line of the joint portion in the first direction is within 15% of the center line of the width of the vibrating piece mounting pad in the first direction, and the end face of the housing portion of the vibrating piece mounting pad in the long side direction does not overlap with the base portion in a plan view. With this configuration, it is possible to prevent contact between the tip of the vibrating arm and the inner wall surface of the package, while also preventing short circuits. That is, in addition to making the width of the vibrating piece mounting pad smaller than conventional devices, by mounting the tuning fork type piezoelectric vibrating piece near the center in the width direction of the vibrating piece mounting pad, it is possible to secure sufficient space between the tip of the vibrating arm and the inner wall surface of the package. Furthermore, by reducing the width of the stepped portion of the package in the first direction compared to conventional designs, when mounting the tuning fork-type piezoelectric vibrator, the vibrator mounting pad and the base do not overlap, preventing short circuits caused by contact between the opposite polarity wiring pattern on the base of the tuning fork-type piezoelectric vibrator and the metal film on the vibrator mounting pad. However, if the width of the stepped portion of the package in the first direction exceeds 15% of the length of the housing portion in the first direction, depending on the mounting position of the tuning fork-type piezoelectric vibrator, the tip of the vibrating arm of the tuning fork-type piezoelectric vibrator may come into contact with the inner wall surface of the package. Also, even if the width of the stepped portion of the package in the first direction is within 15% of the length of the housing portion in the first direction, if the center of the joint in the first direction is outside the range of 15% or less from the center of the stepped portion in the first direction, the tip of the vibrating arm of the tuning fork-type piezoelectric vibrator may come into contact with the inner wall surface of the package, or the vibrator mounting pad and the base may overlap.

[0009] Furthermore, the two vibrating element mounting pads may have an upward-convex shape with a curved surface whose thickness gradually decreases as they approach each other in the short-side direction of the housing, and the joint may be located on the curved surface of the vibrating element mounting pad. With such a configuration, it is possible to prevent the tuning fork type piezoelectric vibrating element from shifting in the short-side direction of the housing when it is mounted.

[0010] Furthermore, the vibrating element mounting pad may be configured to overlap with only one of the two opposite-polarity metal wiring patterns in a region where its thickness is greater than the location of the joint. With such a configuration, it is possible to prevent the vibrating element mounting pad from coming into contact with the opposite-polarity metal wiring patterns provided in the holding portion and causing a short circuit.

[0011] Furthermore, the joining member may be formed by bumps made of metal. With such a configuration, the bonding strength can be significantly higher compared to when a conductive adhesive is used. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a tuning fork type piezoelectric vibration device that achieves both prevention of contact between the tuning fork type piezoelectric vibrator and the inner wall surface of the package, and prevention of short circuits. [Brief explanation of the drawing]

[0013] [Figure 1] A top view of the tuning fork type piezoelectric oscillator according to the first embodiment, with the cover removed. [Figure 2] A schematic internal side view of a tuning fork type piezoelectric oscillator according to the first embodiment. [Figure 3] A top view of a tuning fork-type piezoelectric vibrator according to the first embodiment. [Figure 4] Enlarged view of the base and retaining area in Figure 1. [Figure 5] Cross-sectional view taken along the center line of the joint in Figure 4. [Figure 6] Enlarged view of the base and retaining area in the conventional technology. [Modes for carrying out the invention]

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this specification, the tuning fork type piezoelectric vibration device is described as a tuning fork type piezoelectric oscillator having a tuning fork type piezoelectric vibrator and an IC. Furthermore, the X-axis direction (X direction) described in each drawing and this specification is the same direction as the X-axis direction of the quartz crystal axis, the Y-axis direction (Y direction) is the same direction as the Y-axis direction of the quartz crystal axis (or the Y' direction tilted a few degrees from the Y axis), and the Z-axis direction (Z direction) is the same direction as the Z-axis direction of the quartz crystal axis (or the Z' direction tilted a few degrees from the Z axis).

[0015] <First Embodiment> Figure 1 is a top view of the tuning fork type piezoelectric oscillator 1 according to the first embodiment, Figure 2 is a schematic internal side view of the tuning fork type piezoelectric oscillator 1 according to the first embodiment, Figure 3 is a top view of the tuning fork type piezoelectric vibrating piece 2 according to the first embodiment, Figure 4 is an enlarged view of the base and the vicinity of the holding part in Figure 1, and Figure 5 is a cross-sectional view cut along the center line of the joint in Figure 4. In this specification, the depth direction in Figure 1 is considered the bottom side of the tuning fork type piezoelectric oscillator 1, and the front direction is considered the top side of the tuning fork type piezoelectric oscillator 1, and the bottom and top surfaces are described accordingly. Also, in Figures 4 and 5, package 3 is omitted.

[0016] The tuning fork type piezoelectric oscillator 1 (hereinafter referred to as piezoelectric oscillator 1) in this embodiment comprises a package 3 having a substantially rectangular housing section 31 with the Y direction as the longer side, a tuning fork type piezoelectric vibrator 2 and an IC 5 housed in the housing section 31, and a lid 4 that is joined to the upper surface of the package 3 to hermetically seal the housing section 31. That is, in the piezoelectric oscillator 1, the tuning fork type piezoelectric vibrator 2 and the IC 5 are housed in the same space (housing section 31). In this embodiment, the longitudinal direction (first direction) of the tuning fork type piezoelectric vibrator 2 is arranged to be substantially parallel to the long side direction of the housing section 31. That is, the longitudinal direction of the tuning fork type piezoelectric vibrator 2 is the Y direction, and the long side direction of the housing section 31 is the first direction.

[0017] Package 3 is a box-shaped body made of an insulating material mainly composed of ceramics such as alumina. For example, it is formed by a lower layer portion 3a, a middle layer portion 3b, and an upper layer portion 3c which are obtained by laminating three ceramic green sheets and integrally firing them. In the present embodiment, among the lower layer portion 3a, the middle layer portion 3b, and the upper layer portion 3c, a rectangular frame-shaped middle layer portion 3b is laminated on the lower layer portion 3a disposed at the bottom most, and a further rectangular frame-shaped upper layer portion 3c is laminated on the middle layer portion 3b. Therefore, the package 3 has a rectangular accommodation portion 31 in a plan view with the upper surface of the lower layer portion 3a as the bottom surface and the middle layer portion 3b and the upper layer portion 3c as frame-shaped dike portions 30. Further, the middle layer portion 3b protrudes toward the accommodation portion 31, and a part of it constitutes a step portion 32 on which the tuning fork type piezoelectric vibrating piece 2 is mounted.

[0018] Also, the package 3 has external terminals 8 made of a metal film on the outer bottom surface (the main surface on the side where the dike portion 30 of the lower layer portion 3a is not provided). In the present embodiment, four external terminals 8 are provided at each corner on the outer bottom surface of the package 3 having a substantially rectangular shape, that is, a total of four. That is, in addition to the two external terminals 8 shown in the figure, two external terminals not shown in the figure are provided. Note that the number of the external terminals 8 provided on the bottom surface of the package 3 is not particularly limited, and can be an appropriate number depending on the size of the package 3, the number of terminals of the external substrate on which the piezoelectric oscillator 1 is mounted, or the use of the piezoelectric oscillator 1 or the like.

[0019] Furthermore, package 3 has IC mounting pads 34 for mounting IC 5 on the bottom surface of the accommodating portion 31 (the upper surface of the lower layer portion 3a). The IC mounting pads 34 are conductively joined to corresponding external mounting terminals (not shown) provided on IC 5 via a bonding material 51. Therefore, package 3 has an IC accommodating portion 31a formed by the bottom surface (the upper surface of the lower layer portion 3a) and the inner surface of the middle layer portion 3b as a part of the accommodating portion 31. The IC mounting pads 34 can be formed, for example, by laminating nickel and gold in this order on the upper surface of a tungsten metallization layer using a technique such as plating. Note that molybdenum may be used instead of tungsten as the metallization layer. The bonding material 51 can be, for example, a gold metal bump. In such a case, IC 5 can be mounted on package 3 by bump bonding. Note that the number of IC mounting pads 34 provided on the bottom surface of the accommodating portion 31 is not particularly limited and can be an appropriate number depending on the number of external mounting terminals of IC 5 to be mounted.

[0020] In this embodiment, package 3 is formed of ceramic, but is not limited to this configuration. For example, package 3 may be formed of quartz or glass.

[0021] Also, the width size L1 of the step portion 32 in the Y direction (the first direction) is formed to be 15% or less of the size L2 of the accommodating portion 31 in the Y direction. Further, the width size L1 of the step portion 32 in the Y direction is preferably not less than the width size of the holding portion 23 of the tuning fork type piezoelectric vibrating piece 2 described later in the Y direction.

[0022] Furthermore, the stepped portion 32 is equipped with a first mounting pad 6a and a second mounting pad 6b, which are electrically bonded to a tuning fork-shaped piezoelectric vibrating piece 2 on their upper surfaces. The first mounting pad 6a and the second mounting pad 6b are formed in parallel with a gap between them. The first mounting pad 6a and the second mounting pad 6b have an upward-convex shape, with the apex near the center in a plan view, and the thickness gradually decreasing towards the periphery. Therefore, the first mounting pad 6a and the second mounting pad 6b are formed in an upward-convex shape with a curved surface such that the thickness decreases as they approach each other in the short-side direction (second direction) of the housing portion 31. The first mounting pad 6a and the second mounting pad 6b are opposite poles to each other and are electrically connected to a plurality of external terminals 8 provided on the outer bottom surface of the package 3 via internal wiring and vias (not shown). In this embodiment, the first mounting pad 6a and the second mounting pad 6b are formed to the full edge 32a in the Y direction (first direction) of the stepped portion 32.

[0023] In this embodiment, the first mounted pad 6a, the second mounted pad 6b, and each external terminal can be formed, for example, by laminating nickel and gold in that order on the upper surface of the tungsten metallized layer using a method such as plating. Molybdenum may be used instead of tungsten as the metallized layer.

[0024] The lid 4 can be, for example, a rectangular metal lid in plan view, with Kovar as the base material. Alternatively, the lid 4 can have a configuration in which a metal brazing material is formed around the periphery on the nickel-plated outer periphery of the surface that joins with the package 3. Furthermore, the lid 4 and the package 3 can be joined by brazing or seam welding.

[0025] The tuning fork-type piezoelectric vibrator 2 is a thin, plate-shaped quartz Z-plate with thickness in the Z direction. The tuning fork-type piezoelectric vibrator 2 comprises a base portion 20, a pair of vibrating arms 21 and 22 formed side-by-side from one end of the base portion 20, projecting (extending) in the +Y direction (first direction), and a holding portion 23 formed from the other end of the base portion 20 in the -Y direction. The holding portion 23 extends a predetermined length from the base portion 20 in the first direction, and then bends in a second direction (+X direction) perpendicular to the first direction. Therefore, the tuning fork-type piezoelectric vibrator 2 has a tuning fork shape in plan view, and the holding portion 23 is formed in a substantially L-shape in plan view. In this embodiment, the base portion 20 is the range from the boundary where the vibrating arms 21 and 22 rise up to the boundary where the holding portion 23 rises up. In this embodiment, the vibrating arms 21 and 22 are formed extending in the +Y direction, but they may also be formed extending in the -Y direction. Furthermore, in this embodiment, the holding portion 23 is formed bent in the +X direction, but it may also be formed bent in the -X direction.

[0026] The shape of the tuning fork-type piezoelectric vibrator 2 in this embodiment (the vibrating arms 21, 22, the base 20, and the holding part 23 that constitute the tuning fork-type piezoelectric vibrator 2) is formed, for example, by wet etching from a quartz plate, which is a quartz crystal made of an anisotropic material.

[0027] Furthermore, the tuning fork-type piezoelectric vibrator 2 has a first excitation electrode and a second excitation electrode, which are configured at different potentials, and lead electrodes drawn out from each of the first and second excitation electrodes via lead electrodes. The first excitation electrode is formed on the front and back main surfaces of one vibrating arm 21 and on the outer and inner surfaces of the other vibrating arm 22 via the lead electrodes. Similarly, the second excitation electrode is formed on the front and back main surfaces of the other vibrating arm 22 and on the outer and inner surfaces of one vibrating arm 21 via the lead electrodes. The lead electrodes drawn out from the first excitation electrode are connected to the joining member 7b, and the lead electrodes drawn out from the second excitation electrode are connected to the joining member 7a. Note that the illustration of each electrode pattern is omitted in Figures 1, 2, and 3.

[0028] In this embodiment, the base portion 20 has a symmetrical shape in plan view (symmetrical in the X direction). Furthermore, the base portion 20 is wider (longer in the X direction) than the vibrating arm portions 21, 22 and the holding portion 23. The base portion 20 is also formed to gradually narrow from the vibrating arm portion 21, 22 side to the holding portion 23 side. In addition, the base portion 20 has two through holes 20a and 20b that penetrate in the Z direction. In this embodiment, the two through holes 20a and 20b are arranged side by side in the X direction. Furthermore, opposite polarity lead electrodes (metal wiring patterns) are formed on the inner wall surfaces of the two through holes 20a and 20b, and the lead electrodes on the front and back sides are routed so that they are connected on their inner wall surfaces. With such a configuration of through holes, electrical conductivity of the lead electrodes can be ensured. Furthermore, by efficiently damping the mechanical vibrations of the tuning fork vibrating arm during operation and suppressing the propagation of vibrations to the joint members 7a and 7b (joints), acoustic leakage can be reduced and the series resonance resistance (CI) can be lowered.

[0029] Each pair of vibrating arms 21 and 22 has a vibrating section 211 and 221 extending from the base 20, and a wide section 212 and 222 (weight section) provided at the tip of each arm, which is wider than the width of the vibrating section 211 and 221.

[0030] The wide sections 212 and 222 are formed continuously from the tip portions of the vibrating sections 211 and 221 via widening sections 213 and 223 that gradually widen in the width direction (X direction). The corners on the tip side of each of the wide sections 212 and 222 are processed to be chamfer.

[0031] Furthermore, long grooves 214 and 224 are formed on the front and back main surfaces of each of the pair of vibrating arms 21 and 22, respectively, for the purpose of further reducing the equivalent series resistance value (Crystal Impedance, CI value). More specifically, the vibrating arm 21 has a long groove 214 formed on its front main surface (front surface) and a long groove (not shown) formed on its back main surface (back surface). The long grooves formed on the front and back surfaces are arranged to face each other in the thickness direction. Similarly, the vibrating arm 22 has a long groove 224 formed on its front main surface (front surface) and a long groove (not shown) formed on its back main surface (back surface). The long grooves formed on the front and back surfaces are arranged to face each other in the thickness direction. The long grooves 214 and 224 formed on the front surfaces of the vibrating arms 21 and 22, and the long groove (not shown) formed on the back surface, are formed on the front and back main surfaces of the vibrating arms 21 and 22 with a predetermined depth (length in the Z direction) and width (length in the X direction). Furthermore, each elongated groove is formed with one end in the Y direction extending to one end of the base 20, and the other end near the boundary between the vibrating sections 211, 221 and the widening sections 213, 223. In other words, all elongated grooves have a longitudinal direction along the direction in which the vibrating arms 21, 22 protrude (Y direction) and a width direction along the direction in which the vibrating arms 21, 22 are arranged side by side (X direction). Such elongated grooves can be formed, for example, by wet etching when forming the outer shape of the tuning fork-type piezoelectric vibrating piece 2.

[0032] In this embodiment, the retaining portion 23 is formed to protrude in the -Y direction from the other end of the base portion 20. That is, the retaining portion 23 is formed to protrude in a first direction from the other end of the base portion 20. Furthermore, the retaining portion 23 is formed by bending in the +X direction after protruding a predetermined distance from the base portion 20. Therefore, the retaining portion 23 has a substantially L-shape in plan view.

[0033] In this embodiment, the holding portion 23 has a connecting member 7b at the tip portion bent in the X direction (the tip portion in the +X direction), and a connecting member 7a on the -X side from the center in the X direction. The connecting member 7a in this embodiment is provided near the center of the holding portion 23 in the X direction, and is provided near the bent portion of the holding portion 23 that protrudes in the +X direction. Furthermore, the connecting member 7a in this embodiment is provided in the +X direction (the direction in which the holding portion 23 protrudes) from the central axis of the two vibrating arms 21 and 22 that is parallel to the Y direction. The connecting members 7a and 7b are Au plated bumps formed by electroplating. The position, shape, and number of connecting members 7a and 7b are not particularly limited. That is, although the connecting members 7a and 7b in this embodiment are elliptical in shape of the same size, they can be of various shapes, and the connecting members 7a and 7b may be of different sizes and external shapes. Furthermore, in this embodiment, two joining members 7a and 7b are formed on the holding portion 23, but any configuration in which multiple joining members are electrically connected to two opposite polarity lead electrodes by a conductive material is acceptable, and there may be three or more Au bumps. In addition, in this embodiment, the joining member 7a is provided near the center in the X direction of the holding portion 23, but it may also be provided at the end opposite to the end where the joining member 7b is provided (the end in the -X direction).

[0034] As shown in Figure 1, the tuning fork-type piezoelectric vibrator 2 is joined and held on the upper surface of the stepped portion 32 of the package 3. More specifically, the first mounting pads 6a and 2 mounting pads 6b of the stepped portion 32 are joined to the joining members 7a and 7b of the tuning fork-type piezoelectric vibrator 2, forming joints. In this embodiment, the first mounting pad 6a is connected to the joining member 7a, and the second mounting pad 6b is connected to the joining member 7b. That is, the first mounting pad 6a and the second mounting pad 6b correspond to the vibrator mounting pads in this invention.

[0035] Furthermore, the mounting position of the tuning fork-type piezoelectric vibrator 2 on the mounting pads 6a and 6b is such that the center line Q in the Y direction of the joining members 7a and 7b (joint portion) falls within a range of 15% in the Y direction (+Y direction and -Y direction) from the center line P in the long side direction (Y direction) of the housing portion 31 of the mounting pads 6a and 6b. At this time, as shown in Figure 4, the mounting pads 6a and 6b and the Y-direction edge 32a of the stepped portion 32 and the base portion 20 of the tuning fork-type piezoelectric vibrator 2 are arranged so that they do not overlap in a plan view.

[0036] Furthermore, the joining members 7a and 7b are connected at the curved portions of the mounting pads 6a and 6b, which have an upward-convex shape. In particular, in this embodiment, the joining members 7a and 7b are connected to the curved surfaces of the mounting pads 6a and 6b, which are spaced apart from each other (see Figure 5). That is, the mounting pads 6a and 6b have an upward-convex curved surface and a thickest part (top), and the tuning fork-type piezoelectric vibrator 2 is positioned in the region of the curved surface that is thinner than the top. Furthermore, in the region where the first mounting pad 6a is thicker than the connection position with the joining member 7a, it superimposes in a plan view only with the lead electrode 2a that is connected to the joining member 7a of the tuning fork-type piezoelectric vibrator 2, and does not superimpose with the lead electrode 2b, which is of the opposite polarity to the lead electrode 2a. Similarly, the second mounted pad 6b, in a region where its thickness is greater than the connection position with the joining member 7b, superimposes in a plan view only with the lead electrode 2b connected to the joining member 7b of the tuning fork-type piezoelectric vibrator 2, and does not superimpose with the lead electrode 2a, which is of the opposite polarity to the lead electrode 2b.

[0037] In this embodiment, the joining members 7a and 7b and the mounting pads 6a and 6b are bump-joined by the FCB (Flip Chip Bonding) method. That is, the Au metal bumps of the joining members 7a and 7b and the Au layer formed on the outermost surface of the mounting pads 6a and 6b are electrically bonded by bump bonding.

[0038] Furthermore, it is preferable that the total length of the tuning fork-type piezoelectric vibrator 2 in the Y direction be 90% or more of the size L2 of the housing 31 in the long side direction (Y direction, first direction). With such a configuration, a small package 3 can be made for a tuning fork-type piezoelectric vibrator 2 that has the required characteristics, and the piezoelectric oscillator 1 can be miniaturized.

[0039] IC5 has a temperature sensor and an oscillation circuit that causes the tuning fork-type piezoelectric vibrator 2 to oscillate. In this embodiment, IC5 is an IC chip having a roughly rectangular parallelepiped shape and has external mounting terminals on its bottom surface that correspond to the IC mounting pad 34. IC5 is electrically connected to the IC mounting pad 34 of package 3 via a bonding material 51.

[0040] The piezoelectric oscillator 1 has a configuration in which the tuning fork-type piezoelectric vibrator 2 and IC 5 are superimposed on each other when the tuning fork-type piezoelectric vibrator 2 and IC 5 are mounted on the package 3. In this configuration, the tuning fork-type piezoelectric vibrator 2 and IC 5 are arranged with a certain gap in the vertical direction (see Figure 2). Furthermore, it is preferable that the vibrating parts 211, 221 and wide parts 212, 222 of the tuning fork-type piezoelectric vibrator 2 are superimposed on IC 5. With such a configuration, the difference between the actual temperature of the vibrating parts 211, 221 and wide parts 212, 222 and the temperature detected by the temperature sensor of IC 5 can be reduced, thereby improving heating drift. Note that contact between the tuning fork-type piezoelectric vibrator 2 and IC 5 is undesirable because it affects the vibration of the tuning fork-type piezoelectric vibrator 2.

[0041] With the above configuration, it is possible to provide a tuning fork type piezoelectric vibration device that achieves both prevention of contact between the tuning fork type piezoelectric vibrator and the inner wall surface of the package, and prevention of short circuits. The piezoelectric oscillator 1 of the present invention is configured such that the width L1 of the housing portion 31 for the mounting pads 6a and 6b of the package 3 in the long side direction (Y direction, first direction) is within 15% of the length (size) L2 of the housing portion 31 in the long side direction, the centerlines Q of the joining members 7a and 7b of the tuning fork type piezoelectric vibrator 2 in the first direction are within 15% of the centerline P of the housing portion 31 for the mounting pads 6a and 6b in the long side direction, and the end faces of the housing portion 31 for the mounting pads 6a and 6b in the long side direction do not overlap with the base portion 20 of the tuning fork type piezoelectric vibrator 2 in a plan view. With this configuration, it is possible to prevent contact between the tips of the vibrating arms 21 and 22 and the inner wall surface of the package 3, while also preventing short circuits. In other words, by reducing the width L1 in the long-side direction of the housing portion 31 for the mounting pads 6a and 6b of the package 3 compared to conventional designs, and by mounting the tuning fork-type piezoelectric vibrator 2 near the center line P in the long-side direction of the housing portion 31 for the mounting pads 6a and 6b, sufficient space can be secured between the tips of the vibrating arms 21 and 22 and the inner wall surface of the package 3. Furthermore, by reducing the width L1 in the long-side direction of the housing portion 31 for the mounting pads 6a and 6b of the package 3 compared to conventional designs, the mounting pads 6a and 6b and the base portion 20 do not overlap in a plan view when the tuning fork-type piezoelectric vibrator 2 is mounted, preventing the metal films of the mounting pads 6a and 6b from making contact that electrically connects the first lead electrode 2a and the second lead electrode 2b of opposite poles provided on the base portion 20 of the tuning fork-type piezoelectric vibrator 2 and causing a short circuit.

[0042] Furthermore, the width L1 of the housing portion 31 of the mounting pads 6a and 6b in the long side direction (Y direction, first direction) is formed to be greater than or equal to the width of the holding portion 23 of the tuning fork-type piezoelectric vibrator 2 in the Y direction. This configuration allows the tuning fork-type piezoelectric vibrator 2 to be held and mounted in the mounting pads 6a and 6b of the package 3 with sufficient holding area (holding strength). In addition, when mounting the tuning fork-type piezoelectric vibrator 2 to the package 3, contact between the inner wall surface of the package 3 and the holding portion 23 of the tuning fork-type piezoelectric vibrator 2 can be prevented.

[0043] Furthermore, the first mounting pad 6a and the second mounting pad 6b are formed in an upward-convex shape with a curved surface whose thickness gradually decreases as they approach each other in the short-side direction (second direction) of the housing section 31, and the joining members 7a and 7b of the tuning fork type piezoelectric vibrator 2 are connected to the curved portions of the mounting pads 6a and 6b. This configuration prevents the tuning fork type piezoelectric vibrator 2 from shifting in the short-side direction (X direction) of the housing section 31 when it is mounted. In addition, by arranging the two joining members 7a and 7b (joints) on opposing curved surfaces of the mounting pads 6a and 6b, the distance between the two joining members 7a and 7b (joints) can be reduced. At this time, the joining member 7a will be closer to the direction in which the holding section 23 protrudes (the tip where the joining member 7b is provided), thus preventing acoustic leakage. In other words, the electrical characteristics of the piezoelectric oscillator 1 can be improved.

[0044] Furthermore, the first mounting pad 6a is configured such that, in a region where its thickness is greater than the connection position with the joining member 7a, it overlaps in a plan view only with the first lead electrode 2a connected to the joining member 7a of the tuning fork-type piezoelectric vibrator 2, and does not overlap with the second lead electrode 2b, which is of the opposite polarity to the first lead electrode 2a. Similarly, the second mounting pad 6b is configured such that, in a region where its thickness is greater than the connection position with the joining member 7b, it overlaps in a plan view only with the second lead electrode 2b connected to the joining member 7b of the tuning fork-type piezoelectric vibrator 2, and does not overlap with the first lead electrode 2a, which is of the opposite polarity to the second lead electrode 2b. In this embodiment, when the joining members 7a and 7b (joint portion) are arranged on a curved surface in mounting pads 6a and 6b having an upward convex shape, the mounting pads 6a and 6b and the holding portion 23 are more likely to come into contact in a region where its thickness is greater than the connection position with the joining members 7a and 7b. However, with the configuration of the present invention, even if the mounted pads 6a and 6b come into contact with the holding portion 23, it is possible to prevent the mounted pads 6a and 6b from coming into contact in a way that electrically connects the first lead electrode 2a and the second lead electrode 2b, which are of opposite polarity and provided on the holding portion 23, respectively. In other words, it is possible to prevent the mounted pads 6a and 6b from coming into contact with the first lead electrode 2a and the second lead electrode 2b, which are of opposite polarity and provided on the holding portion 23, and causing a short circuit.

[0045] Furthermore, the tuning fork-type piezoelectric vibrator 2 of the present invention is mounted to the package 3 by bump bonding using metal bumps. This configuration allows the tuning fork-type piezoelectric vibrator 2 to be bonded more firmly to the package 3 than when bonded with conductive adhesive. On the other hand, compared to the case where the tuning fork-type piezoelectric vibrator 2 is mounted to the package 3 with conductive adhesive, the thickness of the bonded portion is smaller, and the distance between the tuning fork-type piezoelectric vibrator 2 and the stepped portion 32 and mounting pads 6a, 6b in the thickness direction (Z direction) is shorter. In other words, while it is easier for the base 20 and holding portion 23 of the tuning fork-type piezoelectric vibrator 2 to come into contact with the mounting pads 6a and 6b, with the configuration of the present invention, the base 20 of the tuning fork-type piezoelectric vibrator 2 and the mounting pads 6a and 6b do not overlap in a plan view, thus preventing contact. Even if the mounting pads 6a and 6b come into contact with the holding portion 23, it is possible to prevent the mounting pads 6a and 6b from coming into contact in a way that electrically connects the opposite polarity lead electrodes 2a and 2b provided on the holding portion 23, respectively.

[0046] Furthermore, this invention is not limited to the configurations of the embodiments described above, and many other embodiments can be obtained. For example, in this embodiment, the holding portion 23 is configured to bend in the +X direction, but it is not limited to this configuration. That is, the holding portion 23 may be configured to bend in the -X direction, or it may be configured to bend in both the +X and -X directions.

[0047] The embodiments disclosed herein are illustrative in all respects and are not intended to be restrictive. Therefore, the technical scope of the present invention is not construed solely by the embodiments described above, but is defined by the claims. This includes all modifications within the meaning and scope of the equivalents of the claims. [Industrial applicability]

[0048] The tuning fork type piezoelectric vibration device of the present invention can be used in the manufacturing and sales industry of tuning fork type piezoelectric oscillators equipped with a tuning fork type piezoelectric vibrator. [Explanation of Symbols]

[0049] 1... Tuning fork type piezoelectric oscillator 2…Tuning fork-type piezoelectric vibrator 20…Base 21, 22... Vibrating arm part 23...Holding part 3…Package 31... Detention Unit 32...Double part 34…IC-equipped pad 4…Lid 5…IC 6a...First mounted pad 6b...Second mounted pad 7a, 7b... Joining members

Claims

1. A tuning fork type piezoelectric vibration device comprising a tuning fork type piezoelectric vibrator and a package that houses the tuning fork type piezoelectric vibrator in an internal housing, The aforementioned tuning fork-shaped piezoelectric vibrator is The base and, A pair of vibrating arms extending in a first direction from one end of the base, A holding portion extends from the other end of the base in a direction opposite to the extension direction of the vibrating arm and protrudes in at least one of the second directions perpendicular to the first direction, At least the base comprises two metal wiring patterns that are opposite in polarity to each other, The aforementioned retaining part is The package has a joint portion that is joined to the joint member at multiple positions spaced apart in the second direction, The aforementioned package is A vibrating element mounted on a pad that is joined to the aforementioned tuning fork-type piezoelectric vibrating element, The housing portion has a stepped portion on its upper surface which has the vibrating element mounted on the pad, The width of the housing portion of the vibrating element mounting pad in the long-side direction is within the range of 15% or less of the length of the housing portion in the long-side direction, The center line of the joint in the first direction is positioned such that it falls within a range of 15% or less in the first direction from the center line of the housing portion of the vibrating element mounting pad in the long side direction. The end face of the housing portion of the vibrating element mounting pad in the long-side direction does not overlap with the base portion in a plan view. Tuning fork type piezoelectric vibration device.

2. The two vibrating element mounting pads have an upward-convex shape with a curved surface in which their thickness gradually decreases as they approach each other in the short-side direction of the housing portion. The aforementioned joint is positioned on the curved surface in the vibrator mounting pad. The tuning fork type piezoelectric vibration device according to claim 1.

3. The tuning fork-type piezoelectric vibrator superimposes, in a plan view, only one of the two metal wiring patterns that are opposite poles, in a region where the thickness is greater than the position where the joint portion of the vibrator-mounted pad is located. The tuning fork type piezoelectric vibration device according to claim 2.

4. The aforementioned joining member is formed by bumps made of metal. The tuning fork type piezoelectric vibration device according to claim 1, 2, or 3.

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