JP2020065223A - Tuning fork type piezoelectric vibrating piece and tuning fork type piezoelectric vibrator using tuning fork type piezoelectric vibrating piece - Google Patents

Abstract

To provide a tuning fork type piezoelectric vibrating piece and a tuning fork type piezoelectric vibrator using the same increasing the rigidity of a vibrating bowl even when the tuning fork type piezoelectric vibrating piece becomes ultra-small, and having good characteristics that do not easily cause disconnection.SOLUTION: A tuning fork type piezoelectric vibrating piece 2 includes a base 20, vibrating arms 21 and 22 having excitation electrodes 25 and 26 protruding from the base, long grooves G1 to G4 formed on the main surface of the vibrating arm, and protrusions T1, T2, T3, and T4 formed at the base end of each of the long grooves. A flat portion having the same thickness as the surrounding bank portion and an inclined portion having a gradually decreasing thickness are formed on the protrusion. A part of the excitation electrode is formed inside the long groove, and the excitation electrode extends from the long groove to the base portion via the flat portion and the inclined portion of the protrusion.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a piezoelectric vibrating reed having a tuning fork shape and a tuning fork type piezoelectric vibrator using the piezoelectric vibrating reed.

  Piezoelectric vibrators such as tuning fork type piezoelectric vibrators are used in various electronic devices as a reference clock source. For example, a surface-mounted tuning fork type piezoelectric vibrator includes a base portion and a pair of vibrating arms protruding in the same direction from one end side of the base portion, and the pair of vibrating arms includes excitation electrodes for driving the vibrating arms. The tuning-fork type piezoelectric vibrating reed formed with is formed in the recess of the insulating container. The other end of the base of the tuning fork type piezoelectric vibrating piece is conductively bonded to an electrode pad formed on the inner bottom surface of the recess of the container through a conductive bonding material, and a flat plate is formed on the opening end of the recess of the container. The lids are joined together.

  In recent years, as the performance and size of communication devices have increased, the tuning fork-type piezoelectric vibrating piece is required to be further downsized and the quality of its characteristics to be improved. On the other hand, in order to suppress the increase in CI due to the miniaturization of the tuning fork type piezoelectric vibrating piece, a long groove is formed on the main surface of the vibrating arm, and an excitation electrode is formed inside the groove to improve the electric field efficiency. It is an indispensable composition to raise. As the tuning fork type piezoelectric vibrating piece becomes smaller, the ratio of the width of the long groove to the main surface of the vibrating bowl tends to increase, and the depth thereof tends to increase.

  Further, when the tuning fork type piezoelectric vibrating piece is miniaturized, the vibration bowl of the tuning fork type piezoelectric vibrating piece also becomes smaller according to the miniaturization, and in particular, since the length of the vibrating bowl becomes relatively short, it becomes a reference clock source. It has become difficult to support relatively low frequency applications (especially 32.768 KHz used as a clock source for clocks and the like). On the other hand, in each vibrating bowl of the tuning fork type piezoelectric vibrating piece, apart from the vibrating section having the excitation electrode, it is necessary to configure a weight section at the tip of the vibrating section and wider than the vibrating section. May be.

WO2014 / 208251

  In this way, the tuning fork type piezoelectric vibrating piece is further downsized, and the width of the bank portion formed between the end of the vibrating bowl and the long groove becomes narrower than in the conventional case, and it is easy to route the excitation electrode. There is a problem in that the disconnection is likely to occur and the rigidity of the vibration bowl is reduced.

  The present invention has been made in view of the above point, and the tuning fork type piezoelectric vibrating piece which has good characteristics in which the rigidity of the vibrating bowl is increased even when the tuning fork type piezoelectric vibrating piece is made extremely small and the wire breakage is unlikely to occur, and An object of the present invention is to provide a tuning fork type piezoelectric vibrator using a tuning fork type piezoelectric vibrating piece.

  In order to achieve the above object, the invention according to claim 1 provides a base, a plurality of vibrating arms protruding from the base and having excitation electrodes formed therein, a long groove formed on a main surface of the vibrating arm, and a bank around the long groove. The long groove has a longitudinal direction along the protruding direction of the vibrating arm and a width direction along a direction orthogonal to the protruding direction of the vibrating arm. A protrusion is formed at the end portion on the base side in the longitudinal direction, and the protrusion has a flat portion having the same thickness as the bank portion and an inclined portion whose thickness gradually decreases from the flat portion toward the center of the long groove. The flat portion has a protrusion dimension in the longitudinal direction of the long groove that is shorter than the width dimension of the long groove in the width direction, and the inside of the long groove of the vibrating bowl and the protrusion portion formed in the long groove. Of the flat portion and the inclined portion of the long groove from the base portion Wherein a portion of the excitation electrode which extends through the end portion is formed.

  According to the above invention, a protrusion is formed at the end of the long groove of the vibration bowl on the base side in the longitudinal direction, and the protrusion has a flat portion having the same thickness as the bank portion and an inclined portion having a gradually decreasing thickness. Since the protrusion of the flat portion is formed shorter than the width of the long groove, the protrusion does not significantly reduce the volume of the base side region of the long groove of the vibration bowl as a whole, and The rigidity can be increased. As a result, the area of the excitation electrode formed inside the long groove is not significantly reduced, and the electric field efficiency at the time of excitation of the tuning fork type piezoelectric vibrating piece is not reduced, so that the increase in CI is suppressed and good characteristics are obtained. Therefore, the rigidity of the vibration bowl can be increased.

  Moreover, the flat portion of the protrusion is formed to be shorter than the width dimension of the long groove, and at the tip thereof, the inclined portion whose thickness is gradually reduced is formed, so that the rigidity between the tip side and the base side of the vibrating bowl is improved. Since it does not change significantly and the protrusion does not cause an extreme change point in rigidity, the bending vibration of the tuning-fork type piezoelectric vibrating piece is not easily disturbed by the change in rigidity of the vibration bowl, and an unnecessary vibration mode is generated. It can also be suppressed.

  Further, the inside of the long groove of the vibrating bowl and the base portion are extended by a part of the excitation electrode via the protrusion formed of the inclined surface and the short flat portion as described above, and are generated between the long groove and the bank portion. Since the electrode is pulled out in a state in which the step is reduced, it is possible to suppress disconnection of the excitation electrode.

  In addition to the above configuration, the protrusion is formed at the center of the base side end of the long groove, and the flat portion of the protrusion is formed so that the area gradually decreases toward the center of the long groove. May be.

  According to the above invention, in addition to the above-described effects, the protrusion is formed at the center of the base-side end of the long groove, and the flat portion of the protrusion gradually narrows in area toward the center of the long groove. By being formed, the rigidity of the tip end side and the base part side of the vibrating bowl is not significantly changed, and the extreme change point of the rigidity due to the protrusion is not generated. Therefore, it is possible to further suppress the occurrence of an unnecessary vibration mode in which bending vibration of the tuning fork type piezoelectric vibrating piece is less likely to be disturbed.

  In addition to the above-mentioned structure, a wide weight may be formed on the protruding end of the vibrating arm.

  According to the above invention, in addition to the above-described effects, the wide weight portion of the projecting end portion of the vibrating arm can reduce the frequency due to the miniaturization of the tuning fork type piezoelectric vibrating piece, and the weight portion exists. It is possible to cope with further insufficient rigidity due to. As a result, there is no risk of vibrating arms being broken.

  Further, the tuning fork type piezoelectric vibrating piece described above can be applied to a tuning fork type piezoelectric vibrator which is mounted and housed inside a container and is hermetically sealed, and the same effect as the above is obtained. Obtained as.

  As described above, according to the present invention, the tuning fork type piezoelectric vibrating piece and the tuning fork type piezoelectric vibrating piece which have good characteristics such that the rigidity of the vibrating bowl is enhanced even if the tuning fork type piezoelectric vibrating piece is miniaturized and the disconnection does not easily occur. It is possible to provide a tuning fork type piezoelectric vibrator using a piece.

FIG. 3 is a schematic cross-sectional view of a tuning fork type crystal resonator according to the embodiment of the present invention. FIG. 3 is a schematic plan view of one main surface side of the tuning fork type crystal vibrating piece according to the embodiment of the present invention. FIG. 3 is a plan view of the other main surface side of the tuning fork type crystal vibrating piece of FIG. 2. FIG. 8 is a schematic plan view of one main surface side of a tuning fork type quartz vibrating piece according to another embodiment of the present invention.

  Hereinafter, as an embodiment of the present invention, a tuning fork type crystal resonator (tuning fork type piezoelectric resonator) using a tuning fork type crystal resonator element (tuning fork type piezoelectric resonator element) will be described as an example with reference to the drawings. The tuning fork type crystal unit (hereinafter, abbreviated as a crystal unit) in the present embodiment is a surface mount type crystal unit having a substantially rectangular parallelepiped package structure. In the present embodiment, the external dimensions in plan view are, for example, 1.6 mm in length and 1.0 mm in width. The external dimensions of the crystal unit in plan view are not limited to the dimensions, but are suitable for an ultra-small crystal unit having the same size or less.

  A crystal resonator 1 according to an embodiment of the present invention includes a container 3 made of an insulating material having a recess 5 as shown in FIG. 1, a tuning fork type crystal vibrating piece 2 (hereinafter, abbreviated as crystal vibrating piece 2), and a concave portion. The flat plate-shaped lid 4 that seals 5 is a main component. Note that, in FIG. 1, various electrodes formed on the crystal vibrating piece are omitted. The crystal vibrating piece 2 is housed inside the recess 5 of the container 3 and then hermetically sealed by the lid 4 being joined to the open end of the container 3 so as to cover the recess 5. Here, the container 3 and the lid 4 are joined via a sealing material (not shown).

  The container 3 is a box-shaped body made of an insulating material mainly composed of ceramics such as alumina, and is formed by, for example, stacking two ceramic green sheets and integrally firing them (see FIG. 1). The container 3 has a concave portion 5 having a rectangular shape in a plan view inside the frame-shaped bank portion 30. A sealing material (not shown) is formed in a frame shape on the upper surface of the bank 30 in a plan view, and the bonding material corresponds to the outer peripheral portion of the lid 4.

  On one short side of the inner bottom surface 301 of the recess 5, two electrode pads 6 and 7 (only one is shown in FIG. 1) conductively bonded to the crystal vibrating piece 2 are arranged in parallel with each other with a gap therebetween. Has been formed. The two electrode pads 6 and 7 are two of the four external connection terminals 8 (only two are shown in FIG. 1) provided at the four corners of the outer bottom surface 302 of the container 3 via internal wiring and vias not shown. It is electrically connected to two terminals. These two electrode pads 6 and 7 have different polarities.

  In this embodiment, the two electrode pads 6 and 7 are formed by stacking gold on the upper surface of the tungsten metallized layer using a technique such as plating. Note that molybdenum may be used instead of tungsten as the metallized layer.

  The tungsten portions of the electrode pads 6 and 7 are overcoated in two steps from the viewpoint of the minimum unit thickness of metallization. This is because in the present embodiment, since the container 3 has a two-layer structure in order to reduce the thickness of the crystal resonator, it is not possible to form a step on the inner bottom surface 301 of the recess 5, so that the crystal resonator element 2 is mounted. This is to secure a certain gap between the lower surface of the crystal vibrating piece (the surface facing the inner bottom surface 301) and the inner bottom surface 301 in the latter state.

  The lid 4 is a metallic lid body having a rectangular shape in plan view and having Kovar as a base, and nickel plating layers are formed on the front and back surfaces of the lid. A brazing material made of metal is formed over the entire surface of the lid 4 on the side of the joint with the container. In the present embodiment, silver brazing is used as the brazing material.

  Next, the crystal resonator element according to the present embodiment will be described with reference to FIGS. 2 and 3. For convenience of explanation, of the two main surfaces (2a, 2b) of the quartz resonator blank 2 facing each other, the main surface facing the electrode pads 6 and 7 when mounted on a container is a back surface 2b, and the back surface is the back surface 2b. The main surface on the opposite side opposite to is described as the surface 2a. 2 shows a plan view seen from the front surface side (2a) of the crystal vibrating piece, and FIG. 3 shows a plan view seen from the back surface side (2b) of the crystal vibrating piece.

  As shown in FIGS. 2 and 3, the crystal vibrating piece 2 has a tuning fork shape and includes a base portion 20, a pair of vibrating arms 21 and 22 projecting from one end side 201 of the base portion 20 in the same direction, and the other end side of the base portion. The protrusion 24 is formed by projecting from one side surface of the base portion 202 toward one side in the width direction of the base portion 20 (the dimension of the base portion in the axial direction indicated by the symbol X in FIGS. 2 and 3).

  A wide portion 23, which is wider than the arm width of the vibrating arms 21 and 22 (the dimension of the arm in the direction orthogonal to the protruding direction of the vibrating arm), is provided on the distal end side of each of the pair of vibrating arms 21 and 22. 23 (weight part) is formed. The wide portions 23, 23 are integrally formed with the tip end portions of the vibrating arms 21, 22 via a widening portion (reference numeral omitted) that gradually widens in the protruding direction of the vibrating arm. The widened portion and the widened portion are integrally formed with the vibrating arm. Note that the corners on the tip ends 211, 221 of the wide portions 23, 23 are chamfered (C-faced). The vibrating arms 21 and 22, the widened portions and the widened portions 23 and 23 have a pair of side surfaces (reference numeral omitted) that face the pair of main surfaces 2a and 2b that face each other.

  Long grooves G1 to G4 are formed on the front and back main surfaces of each of the pair of vibrating arms 21 and 22 for the purpose of further lowering the equivalent series resistance value (Crystal Impedance; hereinafter, abbreviated as CI value). That is, on the front and back main surfaces of the vibration bowl 21, the long groove G1 and the long groove G3 are formed to face each other, and on the front and back main surface of the vibration bowl 22, the long groove G2 and the long groove G4 are formed to face each other. Has been done. The long grooves G1 to G4 are formed with a predetermined depth on the front and back main surfaces of each of the pair of vibrating arms 21 and 22, one end side of which extends to the region of one end side 201 of the base 20, and the other end side thereof vibrates. Is formed on the base side of the vibrating arm with respect to the boundary between the widened part and the widened part. The long grooves G1 to G4 are in the longitudinal direction along the protruding direction of the vibrating arms 21 and 22 (the axial direction indicated by the symbol Y in FIGS. 2 and 3) and in the direction orthogonal to the protruding direction of the vibrating arms 21 and 22. Along the width direction (the axial direction indicated by the symbol X in FIGS. 2 and 3). Around the long grooves G1 to G4, a bank portion having the same thickness as the vibrating bowl is formed adjacently. The vibrating bowl region in which the long grooves G1 to G4 are present constitutes a vibrating portion.

  Inside the long grooves G1 to G4 formed on the front and back main surfaces of each of the vibrating arms 21 and 22, at the center of the end portion on the base side in the longitudinal direction of each long groove, the long grooves project toward the center position of the long groove in the longitudinal direction. Protrusions T1, T2, T3, T4 are formed. The protrusions T1, T2, T3, T4 have flat portions T11, T21, T31, T41 having the same thickness as the bank portion around the long grooves G1 to G4, and the flat portions are directed from the flat portion to the center positions of the long grooves G1 to G4. The inclined portions T12, T22, T32, and T42 are gradually reduced in thickness. The flat portions T11, T21, T31, T41 of the protrusions of the present embodiment are formed in a plan view shape, for example, in a triangular shape so that the area thereof gradually narrows toward the center positions of the long grooves G1 to G4. Further, as shown in FIG. 4, the planar shape of the flat portions T111, T211, T311, T411 (only the surface 2a is shown) of the protrusions may be a semi-elliptical shape. Not limited to this embodiment, the flat portion of the protrusion may have a configuration in which the area does not gradually decrease toward the central position of the long groove, and may have a rectangular shape in plan view, for example. Further, the present invention is not limited to this embodiment, and the protrusion may be formed not only on the base side end of the long groove in the longitudinal direction but also on the arm tip side end.

  In the flat portions T11, T21, T31, T41 of the protrusions, the projecting dimension L of the long grooves G1 to G4 in the longitudinal direction (center position of the long grooves G1 to G4) is formed shorter than the width dimension W of the long grooves G1 to G4 in the width direction. Has been done. More specifically, when the width dimension W of the long grooves G1 to G4 is 37 to 42 μm, the projecting dimension L of the flat portions T11, T21, T31, T41 of the protrusions is 3 to 15 μm.

  In this way, by forming the protrusion dimension L of the flat portions T11, T21, T31, T41 of the protrusions shorter than the width dimension W in the width direction of the long grooves G1 to G4, the protrusions T1, T2, T3, T4 vibrate. It is possible to increase the rigidity of the base region of the long grooves G1 to G4 of the bowl without significantly reducing the overall volume of the region.

  Further, in the present embodiment, the protrusions T1, T2, T3, T4 are formed in the center of the base-side end of the long grooves G1 to G4, and the flat portions T11, T21, T31, T41 of the protrusions are It is formed in a shape such as a triangular shape or a semi-elliptical shape in which the area in plan view is gradually reduced toward the center position of the long grooves G1 to G4, and the slope where the wall thickness is gradually reduced at the tip of the flat portion of the protrusion. The formation of the portions T12, T22, T32 and T42 is combined with each other. Therefore, the rigidity of the tip side of the vibrating bowl and the base side of the vibrating bowl are not significantly changed, and the protrusion does not cause an extreme change point of the rigidity, so that the bending vibration of the tuning fork type piezoelectric vibrating piece is not easily disturbed. This is a more preferable form that can further suppress the generation of an unnecessary vibration mode.

  The inside of the long grooves G1 to G4 of the vibration bowls 21 and 22, the flat portions T11, T21, T31, T41 of the protrusions formed in the long grooves G1 to G4, and the inclined portions T12, T22, T32, T42 will be described later. Part of the first and second excitation electrodes 25, 26 is formed. The first and second excitation electrodes 25 and 26 are extended from the end portion on the base side of the long groove to the base portion 20 via the inclined portion and the flat portion of each protruding portion, and one of the extraction electrodes 27 and 28 to be described later. Connected to the department. For this reason, since the excitation electrode is pulled out in a state in which the step generated between the long groove and the surrounding bank portion is reduced, disconnection of the excitation electrode can be suppressed.

  Here, the long groove G1 and the long groove G2 formed in the vibration bowl 21 and the vibration bowl 22 and the protrusions T1 and T2 are formed line-symmetrically with respect to the virtual center line CL between the vibrating arm 21 and the vibration bowl 22. In addition, the long groove G3, the long groove G4, and the protrusions T3 and T4 are formed line-symmetrically with respect to the virtual center line CL between the vibrating arm 21 and the vibrating bowl 22. As a result, the electric fields applied to the vibrating bowls 21 and 22 via the excitation electrodes 25 and 26, which will be described later, are uniformly balanced by the vibrating bowls, and unnecessary vibration is not promoted.

  The base portion 20 is formed with a reduced width portion 203 in which the width of the base portion on the other end side 202 side is narrower than that on the one end side 201 side. The above-mentioned protruding portion 24 is formed on one side surface of the reduced width portion 203. The projecting portion 24 and the base portion 20 form an "L" -shaped portion of the alphabet which is bent at a right angle in a plan view. The tuning-fork type crystal vibrating piece is not limited to the shape in this embodiment. For example, the protruding portion may have a shape protruding from not only one side surface of the base portion but also the other side surface of the base portion (side surface facing the one side surface), that is, the protruding portion may protrude to both outer sides of the base portion. Alternatively, the protrusions may have a bilaterally symmetrical shape that protrudes outward from both sides of the base and then turns in the protruding direction of the vibrating arm to protrude in parallel with each other. Further, it may have a shape in which the protrusion is not formed on the base.

  A large number of outer shapes and projections of the crystal vibrating piece described above are simultaneously molded from one crystal wafer using a photolithography technique and wet etching.

  The crystal vibrating piece 2 includes a first excitation electrode 25 and a second excitation electrode 26 which are configured with different potentials, and a routing electrode (described later) from each of the first excitation electrode 25 and the second excitation electrode 26. Lead-out electrodes 27 and 28 led out via.

  In addition, a part of the first and second excitation electrodes 25 and 26 formed on the front and back main surfaces of the pair of vibrating arms 21 and 22 includes flat portions T11, T21, T31, T41 of the protrusion and the inclined portion T12. , T22, T32, T42 are formed over the entire inside of the long grooves G1 to G4 of the pair of vibrating arms 21 and 22. By forming the long groove, the electric field efficiency of the pair of vibrating arms 21 and 22 is increased and a good CI value can be obtained even if the crystal vibrating piece is downsized. In addition, the first and second excitation electrodes are always formed on the flat portions T11, T21, T31, T41 and the inclined portions T12, T22, T32, T42 of the protrusions, and the inside of the long grooves G1 to G4 is formed. The first and second excitation electrodes may not be formed in some regions.

  The first excitation electrode 25 is formed on the front and back main surfaces of the one vibrating arm 21 and on the outer side surface and the inner side surface of the other vibrating arm 22 via a routing electrode (reference numeral omitted). Similarly, the second excitation electrode 26 is formed on the front and back main surfaces of the other vibrating arm 22 and on the outer side surface and the inner side surface of the one vibrating arm 21 via the routing electrodes (reference numeral omitted).

  The extraction electrodes 27 and 28 are formed on the base 20 and the protrusion 24 (only the back surface 2b). By the extraction electrode 27 formed on the base portion 20, the first excitation electrode 25 formed on each of the outer side surface and the inner side surface of the other vibrating arm 22 and the leading electrode (reference numeral omitted) It is connected to the first excitation electrode 25 formed on the front and back main surfaces of the vibrating arm 21. Similarly, the extraction electrode 28 formed on the base portion 20 passes through the second excitation electrode 26 formed on each of the outer surface and the inner surface of the one vibrating arm 21 and the routing electrode (reference numeral omitted). , And is connected to the second excitation electrode 26 formed on the front and back main surfaces of the other vibrating arm 22.

  The extraction electrodes 27 and 28 are drawn out from the one end side 201 of the base portion 20 to the reduced width portion 203 on the surface 2 a of the crystal vibrating piece. On the other hand, on the back surface 2b of the crystal vibrating piece, it is pulled out to the other end side 202 and the tip side of the projecting portion 24. As shown in FIG. 3, the region on the other end side 202 of the base portion 20 and the regions on the tip end side of the projecting portion 24 on the back surface 2b of the quartz crystal vibrating piece are electromechanical with the electrode pads 6 and 7 of the container 3, respectively. Are connection electrodes 271, 281 connected to.

  As shown in FIG. 3, conductive bonding materials S and S are formed on the upper surfaces of the two connection electrodes 271 and 281 respectively. In the present embodiment, the bonding material S is a plated bump formed by the electrolytic plating method. Conductive bonding between the crystal vibrating piece 2 and the electrode pads 6 and 7 is performed by the FCB method (Flip Chip Bonding).

  The routing electrodes described above are respectively formed on all of the pair of main surfaces and the pair of side surfaces forming the wide portions 23, 23. In the present embodiment, the lead-out electrodes are formed on the entire circumference of the wide portion 23 and the entire circumference (a pair of main surfaces and a pair of side surfaces) of a portion of the vibrating arms 21 and 22 near the widened portion.

  The above-mentioned first and second excitation electrodes 25 and 26, extraction electrodes 27 and 28, and routing electrodes (reference numeral omitted) have a chromium (Cr) layer formed on a quartz substrate, and a gold (Cr) layer is formed on the chromium layer. It has a layered structure in which (Au) layers are laminated. The layer structure of the various electrodes is not limited to the layer structure in which the gold layer is formed on the chromium layer, and may be another layer structure.

  The first and second excitation electrodes, the extraction electrodes, and the routing electrodes are formed on the entire main surface of the quartz wafer by vacuum vapor deposition, sputtering, etc., and then simultaneously formed into a desired pattern by photolithography and metal etching. It is molded.

  As shown in FIG. 2, in the embodiment of the present invention, the frequency adjusting metal film W (frequency adjusting weight) is formed only on one main surface (surface 2a) of the surfaces forming the wide portion 23. The frequency of the crystal vibrating piece 2 is finely adjusted by reducing the mass of the frequency adjusting metal film W by irradiation with a beam such as a laser beam or an ion beam. The frequency adjusting metal film W is formed so that the area in plan view is one size smaller than that of the leading electrode on the main surfaces of the wide portions 23, 23.

  The present invention can be embodied in various other forms without departing from the spirit or the main characteristics thereof. Therefore, the above-described embodiments are merely examples in all respects and should not be limitedly interpreted. The scope of the present invention is defined by the scope of the claims, and is not restricted by the text of the specification. Furthermore, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  It can be applied to mass production of tuning fork type piezoelectric vibrating reeds and tuning fork type piezoelectric vibrators.

1 tuning fork type crystal resonator 2 tuning fork type crystal vibrating piece 20 base 21, 22 vibrating arm 23 wide part 24 protruding part 25, 26 excitation electrode 27, 28 extraction electrode 3 container G1, G2, G3, G4 long groove T1, T2, T3 , T4 protrusion

Claims (3)

base,
A plurality of vibrating arms protruding from the base and having excitation electrodes formed thereon;
It comprises a long groove formed on the main surface of the vibrating arm and a bank portion around the long groove,
The long groove has a longitudinal direction along the protruding direction of the vibrating arm and a width direction along a direction orthogonal to the protruding direction of the vibrating arm,
A protrusion is formed at the end of the long groove on the base side in the longitudinal direction,
The projection portion includes a flat portion having the same thickness as the bank portion and an inclined portion having a thickness that gradually decreases from the flat portion toward the center of the long groove,
The projecting dimension in the longitudinal direction of the long groove of the flat portion is formed shorter than the width dimension of the long groove in the width direction,
The inside of the long groove of the vibrating bowl, the flat portion and the inclined portion of the protrusion formed in the long groove,
A part of the excitation electrode extended from the base via the base side end of the long groove is formed,
A tuning fork type piezoelectric vibrating piece characterized by the following. The tuning fork mold according to claim 1, wherein the protrusion is formed at the center of the end portion of the long groove on the base side, and the flat portion of the protrusion gradually narrows toward the center of the long groove. Piezoelectric vibrating piece.   A tuning fork type piezoelectric vibrator in which the tuning fork type piezoelectric vibrating piece according to claim 1 or 2 is mounted and housed inside a container and hermetically sealed.

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