JP2010074246A - Dual tuning fork type piezoelectric vibration piece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dual tuning fork type piezoelectric vibration piece capable of preventing an excitation electrode from electrically floating even if an extraction electrode connecting the excitation electrodes is disconnected. <P>SOLUTION: The dual tuning fork type piezoelectric vibration piece includes: a center end extraction electrode connected from surface excitation electrodes 54 and 62 or back surface excitation electrodes 56 and 64 in a second area 30 held between a first area 28 and a third area 32 adjacent to proximal ends 12 and 22 of excitation areas sectioned into three areas to inner side face excitation electrodes 42, 50, 74 and 82 and outer side face excitation electrodes 44, 52, 76 and 84 in one of the first area 28 and the third area 32; and an end center extraction electrode connected from surface excitation electrodes 70 and 78 in the third area 32 or back surface excitation electrodes 40 and 48 in the first area 28 to inner side face excitation electrodes 58 and 66 and outer side face excitation electrodes 60 and 68 in the second area 30. Voltages of the potential of opposite polarities are applied to the respective adjacent excitation electrodes. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a double tuning fork type piezoelectric vibrating piece, and more particularly to a double tuning fork type piezoelectric vibrating piece having an electrode structure suitable for miniaturization.

  A double tuning fork type piezoelectric vibrating piece having a vibrating beam as an excitation part between two base end parts detects the distance between the support parts to which the base end parts are fixed and fluctuations in the force applied between the support parts. And is used for pressure sensors, acceleration sensors, and the like (see, for example, Patent Document 1).

  As shown in FIG. 4, the double tuning fork type piezoelectric vibrating piece is divided into three regions with respect to the two vibrating beams 3a and 3b stretched in parallel between the base end 2a and the base end 2b. Excitation electrodes 4a, 4b, 4c, 5a, 5b, and 5c are provided in the respective vibration regions. The excitation electrodes 4a to 4c and 5a to 5c in the respective regions are formed on the front surface, the back surface, the inner surface, and the outer surface, respectively, so that the front and rear surfaces, the inner surface and the outer surface have the same potential, respectively. Are electrically connected to the input / output electrodes 6a and 6b. Further, the excitation electrodes 4a to 4c and 5a to 5c divided into three regions are the first region adjacent to the base end portions 2a and 2b, the excitation electrodes 4a, 5a, 4c, and 5c in the third region, and the first region. The potential is reversed between the excitation electrodes 4b and 5b in the second region located between the excitation electrodes in the region and the third region. The extraction electrodes 7a and 7b that connect the excitation electrodes of the conventional double tuning fork type piezoelectric vibrating piece 1 configured as described above have the excitation electrodes 4a to 4c and 5a to 5c drawn in one stroke with respect to the vibration beams 3a and 3b. It is configured to be connected.

  4A is a plan view showing a configuration of a conventional double tuning fork type piezoelectric vibrating piece, and FIG. 4B is a plan view showing a state in which the configuration of the back side electrode is transmitted. is there.

In order to improve such a double tuning fork type piezoelectric vibrating piece to a small size, the length of the vibration beam may be shortened. However, if the vibration frequency (resonance frequency) before and after the improvement is made equal, the vibration is reduced. The length of the beam is shortened and the vibration beam is formed narrow.
That is, as the double tuning fork type piezoelectric vibrating piece is miniaturized, the vibration that is excited shifts to the lower frequency side as the length of the vibrating beam is shortened. Therefore, in order to make the double tuning fork type piezoelectric vibrating piece compact without changing the excited frequency, the length of the vibrating beam is made shorter and the thickness of the resonant beam is made thinner, thereby both What is necessary is just to cancel the change of the frequency accompanying the processing.
JP 2007-187463 A

  However, since the extraction electrodes that electrically connect the excitation electrodes formed on the front and back surfaces of the vibration beam and the excitation electrodes formed on the inner and outer surfaces of the two vibration beams are thin, the double tuning fork type piezoelectric vibrating piece When the vibration beam becomes thinner as the size is reduced, there is a risk of disconnection due to the effect of mask alignment deviation when the excitation electrode is formed. That is, if the size of the double tuning fork type piezoelectric vibrating piece is reduced, for example, the improvement of the processing accuracy of an apparatus for manufacturing the double tuning fork type piezoelectric vibrating piece may not be caught up. Therefore, the ratio of the manufacturing error amount by the manufacturing apparatus to the dimension of the double tuning fork type piezoelectric vibrating piece increases. For example, in the case of forming the excitation electrode in FIG. 4A, a processing technique called photolithography using an exposure mask is used to form the metal film only within a predetermined range on the vibration beam. Since there is a range in the mask placement accuracy, the mask may be displaced downward from the paper surface from an appropriate position. If the pattern of the mask becomes fine with the miniaturization of the double tuning fork type piezoelectric vibrating piece, the formation position of the metal film will be greatly shifted even if the mask is slightly displaced. In particular, the extraction electrode belongs to a class having a small size among the constituent elements of the double tuning fork type piezoelectric vibrating piece. Therefore, a mask pattern for forming an extraction electrode for connecting, for example, the excitation electrode 4b formed on the outer surface of the vibration beam and the excitation electrode 4c formed on the surface by the displacement of the mask is the outer surface of the vibration beam. May not be reached. Therefore, when the metal film is processed in this state, the extraction electrode is not connected to the excitation electrode 4b on the outer surface, and the extraction electrode is connected between the excitation electrodes as described above, as described above. When a disconnection occurs in the extraction electrode, the excitation electrode is in an electrically floating state, resulting in an increase in vibration loss, a deterioration of the CI value, and a cause of oscillation failure.

  Therefore, in the present invention, even when the vibration beam becomes thinner due to the miniaturization of the double tuning fork type piezoelectric vibrating piece, the excitation electrode is electrically floated by the disconnection of the extraction electrode connecting the excitation electrodes. An object of the present invention is to provide a double tuning fork type piezoelectric vibrating piece having an electrode structure that can be prevented.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  [Application Example 1] A pair of base end portions and two vibration beams stretched in parallel between the base end portions are arranged, and each vibration beam is arranged in order in the extending direction of the vibration beam. As the excitation region divided into two, two end regions adjacent to the base end portion and a central region sandwiched between the two end regions are provided, and two excitation regions are provided in each of the excitation regions. A surface aligned in the same plane when the vibration beam is aligned side by side, a back surface located on the back side of the surface, an inner surface facing between the two vibration beams, and the space between A double tuning fork type piezoelectric vibrating piece having an excitation electrode formed on an outer surface facing a direction opposite to the direction in which it is located, and the two tuning-fork type piezoelectric vibrating pieces formed on the front surface or the back surface in the central region; The inner surface in either one of the end regions and A central end extraction electrode connected to two excitation electrodes arranged on the outer side surface, and one excitation electrode formed on the front surface or the back surface of either one of the two end regions in the central region. A double tuning fork type piezoelectric vibrating piece having an end center extraction electrode connected to two excitation electrodes disposed on an inner surface and an outer surface.

  In the case of a double tuning fork type piezoelectric vibrating piece having such characteristics, even if the vibration beam becomes thinner due to the miniaturization of the double tuning fork type piezoelectric vibrating piece, it is caused by disconnection of the extraction electrode that connects the excitation electrodes. It is possible to prevent the excitation electrode from being electrically floated.

  [Application Example 2] The double tuning fork type piezoelectric vibrating piece according to Application Example 1, wherein the center end lead electrode and the end center lead electrode are respectively formed from excitation electrodes formed on the front surface or the back surface. A double tuning fork type piezoelectric vibrating piece, wherein one drawn electrode is branched into two and connected to an excitation electrode formed on the inner surface or the outer surface.

  According to the double tuning fork type piezoelectric vibrating piece having such a feature, two extraction electrodes are extracted from the excitation electrode formed on the front surface or the back surface, and connected to the excitation electrodes formed on the inner surface or the outer surface, respectively. The pattern can be made simpler than the configuration to be performed. In addition, since there is no need to make the individual extraction electrodes extremely thin, the electrical resistance can be reduced.

  Application Example 3 The double tuning fork type piezoelectric vibrating piece according to Application Example 1 or Application Example 2, wherein the excitation electrode formed on the front surface or the back surface in the end region and the inner surface in the end region Alternatively, when the excitation electrode formed on the outer surface is connected by the extraction electrode, a metal pattern straddling the surface located in the direction intersecting the longitudinal direction of the vibration beam in the base end portion is also provided, A double tuning fork type piezoelectric vibrating piece, wherein a metal pattern is also connected to an excitation electrode formed on the inner side surface or the outer side surface.

  According to the double tuning fork type piezoelectric vibrating piece having such a feature, even when conducting, for example, with one extraction electrode to the inner surface excitation electrode and the outer surface excitation electrode provided in the end region, The risk of disconnection can be reduced.

  [Application Example 4] The double tuning fork type piezoelectric vibrating piece according to any one of Application Examples 1 to 3, wherein a concave groove is provided on a front surface and a back surface of the vibration beam, and a cross-sectional shape of the vibration beam is an H shape. A double tuning fork type piezoelectric vibrating piece characterized by

  According to the double tuning fork type piezoelectric vibrating piece having such characteristics, even when the double tuning fork type piezoelectric vibrating piece is downsized, the vibration loss of the vibration beam is low and the CI value can be kept low.

Hereinafter, embodiments of a double tuning fork type piezoelectric vibrating piece of the present invention will be described in detail with reference to the drawings.
As shown in FIGS. 1 and 2, the double tuning fork type piezoelectric vibrating piece according to the embodiment includes a piezoelectric element plate and an electrode pattern formed on the piezoelectric element plate. 1A is a side view of FIG. 1B as viewed from the vibrating beam 24 side, and FIG. 1B is a plan view of a double tuning fork type piezoelectric vibrating piece. FIG. 1C is a side view of FIG. 1B viewed from the vibration beam 26 side, and FIG. 1D is a plan view showing the configuration of the back side electrode of the double tuning fork type piezoelectric vibrating piece. 2A is a plan view of the double tuning fork type piezoelectric vibrating piece, FIG. 2B is a view showing a cross section taken along the line AA in FIG. 2A, and FIG. It is a figure which shows the BB cross section in a figure (A).

  The piezoelectric element plate has two base end portions 12 and 22 and two vibration beams 24 and 26 laid in parallel between the two base end portions 12 and 22. The piezoelectric element plate is a member capable of producing a piezoelectric effect, and is not particularly limited as long as a desired vibration form can be obtained. Will be adopted.

  Further, the base end portions 12 and 22 of the double tuning fork type piezoelectric vibrating piece 10 according to the present embodiment include fixing portions 16 and 20 for fixing the double tuning fork type piezoelectric vibrating piece 10, fixing portions 16 and 20, and a vibration beam. 24, 26, and connecting portions 14, 18 that are actually connected to the vibration beams 24, 26 so that the vibration beams 24, 26 and the base end portions 12, 22 are integrated. By providing the constricted portions 15 and 19 between the fixed portions 16 and 20 and the connecting portions 14 and 18 at the base end portions 12 and 22, leakage of vibrations excited by the vibration beams 24 and 26, and the fixed portions 16 and 20. It becomes possible to suppress the influence of the external stress propagated from. Further, the vibration beams 24 and 26 in the present embodiment are formed to have a rectangular cross-sectional shape.

  The vibration beams 24 and 26 include a first vibration beam 24 and a second vibration beam 26. In the vibration beams 24 and 26, one of the main surfaces of the base end portion 12, for example, in this embodiment, the side on which the input / output electrodes 34 and 36 are formed is referred to as the front surface, and the other surface is referred to as the back surface. Further, the side surfaces of the first vibration beam 24 and the second vibration beam 26 arranged in parallel are positioned on the inner side surface, and on the opposite side of the inner surface in each of the first vibration beam 24 and the second vibration beam 26. The side surface to be referred to is referred to as the outer surface.

  The electrode pattern is roughly composed of excitation electrodes 38 to 84, extraction electrodes 100 to 117, and input / output electrodes 34 and 36. The excitation electrodes 38 to 84 are electrodes for exciting the first vibration beam 24 and the second vibration beam 26 described above, and are divided into three excitation regions (first region 28 to third region 32). Is provided. In each vibration region in the first vibration beam 24 and the second vibration beam 26, metal patterns as excitation electrodes 38 to 84 are formed on the front surface, back surface, inner surface, and outer surface, respectively. Part of the excitation electrodes 42, 44, 50, 52, 58, 60, 66, 68 formed on the inner and outer surfaces of the first vibration beam 24 and the second vibration beam 26 is a front surface and a back surface. It is arrange | positioned so that it may straddle.

  Here, the vibration region from the first region 28 to the third region 32 is a point that becomes a resonance node when the vibration beams 24 and 26 vibrate, that is, the displacement of the vibration beams 24 and 26 is a second order differential coefficient. When it is obtained, it is preferable to classify at the point where the secondary differential coefficient becomes zero.

  The extraction electrodes 100 to 117 are electrodes that electrically connect the excitation electrodes 38 to 84 described above or the excitation electrodes 38 to 84 and the input / output electrodes 34 and 36. Therefore, the extraction electrodes 100 to 117 are arranged in a metal pattern as will be described in detail later between the plurality of excitation electrodes 38 to 84 or between the excitation electrodes 38 to 84 and the input / output electrodes 34 and 36. Become.

  The input / output electrodes 34 and 36 are electrodes provided on one of the fixed portions of the base end portions 12 and 22 (in the case shown in FIG. 1, the fixed portion 16 of the base end portion 12). It is connected to a terminal (not shown) of a device on which the piezoelectric vibrating piece 10 is mounted, and contributes to input / output of a signal for applying a voltage to the excitation electrodes 38 to 84 and a signal obtained by excitation.

  The extraction electrodes 100 to 117 that connect the input / output electrodes 34 and 36 and the excitation electrodes 38 to 84 have a form as shown in FIG. 1, and as described below, the excitation electrodes or the input / output electrodes and the excitation electrodes are excited. It is connected to the electrode.

  The extraction electrode 100 extracted from the first input / output electrode 34 (hereinafter, the input / output electrode 34 is referred to as the first input / output electrode for convenience) is the outer surface excitation electrode 44 of the first region 28 in the first vibration beam 24. Is connected to the base end portion 12 side end portion. When the extraction electrode 100 is routed from the first input / output electrode 34 to the outer surface excitation electrode 44, the direction of the connection portion 14 at the base end portion 12 intersects the longitudinal direction (extension direction) of the vibration beams 24 and 26. It is preferable to arrange a metal pattern also on the surface 90a located at the position. That is, the connecting portion 14 has a portion protruding from the outer surface of the first vibration beam 24 in a direction intersecting with the extending direction of the vibration beam. And by setting it as such a structure, the arrangement | positioning of the mask for exposure used at the time of metal pattern formation shifted | deviated slightly with respect to the suitable position toward the paper surface of FIG. The position of the outer surface excitation electrode 44 (extended portion of the extraction electrode 100) slightly formed along the edge on the surface in the first region is also shifted downward. Due to this deviation, the crystal plane is exposed between the outer surface excitation electrode 44 on the surface in the first region and the outer surface excitation electrode 44 on the outer surface, and the conduction path is cut off. On the other hand, with respect to the metal pattern formed on the outer surface 90a, the metal pattern connecting the extraction electrode 100 and the outer surface excitation electrode 44 is completely disconnected only by shortening the length in the direction intersecting the extending direction. Never do. As a result, disconnection of the extraction electrode 100 can be prevented. In FIG. 1B, when the arrangement of the mask used for forming the metal pattern is shifted to the right with respect to the paper surface, for example, the extraction electrode formed on the upper surface of the protruding portion of the connecting portion 14. Then, the surface of the crystal is exposed between the outer surface excitation electrode 44 formed on the outer surface of the protruding portion of the connecting portion 14. However, since the outer surface excitation electrode 44 and the outer surface excitation electrode 44 on the surface in the first region 28 of the first vibration beam 24 are connected, the disconnection of the extraction electrode 100 can be prevented.

  The outer surface excitation electrode 44 of the first region 28 in the first vibration beam 24 includes an extraction electrode 101 routed from the end of the outer surface excitation electrode 44 on the second region 30 side to the surface of the first vibration beam 24, and a base electrode. In this configuration, the end electrode 12 is electrically connected to the extraction electrode 102 drawn from the end on the side of the end 12 toward the back side of the base end 12. The extraction electrode 101 is bifurcated within the surface of the first vibration beam 24. That is, the extraction electrode 101 has one extraction electrode formed in a region between the surface excitation electrode 54 and the surface excitation electrode 38 in the second region 30 of the first vibration beam 24 in the surface and the one extraction electrode. It has a lead-out electrode branched into two branches from one end of the electrode. The extraction electrode 101 is connected by connecting the other end of one extraction electrode to the surface excitation excitation electrode 54 and connecting one branched extraction electrode to the end of the outer vibration electrode 44 on the first region 28 side. The other extraction electrode is connected to the second region 30 side end of the inner surface excitation electrode 42 of the first region 28 in the first vibration beam 24. Then, from the end portion on the base end portion 12 side of the inner surface excitation electrode 42, the extraction electrode 103 led to the surface side of the base end portion 12 is extracted. The extraction electrode 103 led to the surface side of the base end portion 12 is connected to the base end portion 12 side end portion of the surface excitation electrode 46 in the first region 28 in the second vibration beam 26.

  On the other hand, the extraction electrode 102 drawn to the back surface side of the base end portion 12 is connected to the base end portion 12 side end portion of the back surface excitation electrode 48 in the first region 28 in the second vibration beam 26.

  The extraction electrode 104 is on the back side of the second vibration beam 26 and exists between the first region 28 and the second region 30. Further, the extraction electrode 104 has a three-pronged structure having three branches, one end of one branch is connected to the back surface excitation electrode 48 of the first region 28, and one end of the other branch is connected to the inner side. It is connected to the side excitation electrode 66, and one end of the remaining branch is connected to the outer side excitation electrode 68.

  The extraction electrode 105 is formed on the surface of the second vibration beam 26 from the end on the third region 32 side of the inner surface excitation electrode 66 of the second region 30 and the end of the outer surface excitation electrode 68 on the third region 32 side. The extracted electrode is connected to one end of one extraction electrode within the surface of the second vibration beam 26, and the other end of the one extraction electrode is connected to the surface excitation electrode of the third region 32 in the second vibration beam 26. 78 is connected to the end of the second region 30 side.

  The extraction electrode 106 drawn from the base end 22 side end of the surface excitation electrode 78 in the third region 32 of the second vibration beam 26 is drawn around the surface of the base end portion 22 and the first vibration beam 24 in the first vibration beam 24. The outer surface excitation electrode 76 of the third region 32 is connected to the end portion on the base end portion 22 side. When the extraction electrode 106 is routed to the outer side excitation electrode 76, a metal pattern may be arranged on the surface 90c of the connection portion 18 at the base end portion 22.

  In the first vibration beam 24, the extraction electrode 107 extracted from the end of the outer surface excitation electrode 76 of the third region 32 on the second region 30 side to the back surface is one extraction electrode having one end connected to the outer surface excitation electrode 76. The other end of the two branches into two branches. In the branched extraction electrode 107, one of the branch paths is connected to the third region 32 side end of the back surface excitation electrode 56 of the second region 30 in the first vibration beam 24, and the other is the third in the first vibration beam 24. The inner surface excitation electrode 74 of the region 32 is connected to the end of the second region 30 side.

  The extraction electrode 108 drawn from the end of the inner surface excitation electrode 74 of the third region 32 in the first vibration beam 24 toward the back surface of the base end 22 is the third region 32 in the second vibration beam 26. The back surface excitation electrode 80 is connected to the proximal end portion 22 side end portion. When the extraction electrode 108 is routed from the inner surface excitation electrode 74 to the back surface side of the base end portion 22, the metal pattern is also disposed on the connection portion of the vibration beams 24 and 26, so-called fork 92 b. It is preferable to prevent disconnection of the extraction electrode 108 due to mask displacement at the time of formation.

  The extraction electrode 110 extracted from the second input / output electrode 36 (hereinafter, the input / output electrode 36 is referred to as a second input / output electrode for convenience) is branched, and one of the branch paths is the first region in the first vibration beam 24. The other end of the surface excitation electrode 38 is connected to the proximal end 12 side end and the other end of the second vibration beam 26 is connected to the proximal end 12 side end of the outer surface excitation electrode 52 of the first region 28. In order to route the extraction electrode 110 to the outer surface excitation electrode 52 of the first region 28, the surface 90b of the connection portion 14 in the base end portion 12 is also used, thereby preventing disconnection due to mask displacement at the time of forming the metal pattern. it can.

  The extraction electrode 111 formed between the surface excitation electrode 62 and the surface excitation electrode 46 in the second region 30 in the second vibration beam 26 has one end of one extraction electrode connected to the surface excitation electrode 62. The other end of the extraction electrode is branched at the surface of the second vibration beam 26. In the branched extraction electrode 111, one of the branch paths is connected to the second region 30 side end of the inner surface excitation electrode 50 of the first region 28 in the second vibration beam 26, and the other is connected to the second vibration beam 26 in the second vibration beam 26. The surface excitation electrode 62 in the second region 30 is connected to the end of the first region 28 side.

  The extraction electrode 112 extracted from the end of the inner surface excitation electrode 50 in the first region 28 of the second vibration beam 26 toward the back surface of the base end portion 12 is connected to the first region 28 of the first vibration beam 24. The back surface excitation electrode 40 is connected to the proximal end portion 12 side end portion. When routing from the inner surface excitation electrode 50 to the back surface side of the base end portion 12, it is possible to prevent disconnection by arranging a pattern also on the fork 92 a.

  The extraction electrode 113 extracted from the end of the back surface excitation electrode 40 of the first region 28 in the first vibration beam 24 on the second region 30 side is bifurcated on the back surface of the first vibration beam 24. In the branched extraction electrode 113, one of the branch paths is connected to the first region 28 side end of the outer surface excitation electrode 60 of the second region 30 in the first vibration beam 24, and the other is connected to the second region 30. The inner surface excitation electrode 58 is connected to the first region 28 side end.

  The extraction electrode 114 is drawn to the surface from the end on the third region 32 side of the outer surface excitation electrode 60 of the second region 30 and the end of the inner surface excitation electrode 58 on the third region 32 side of the first vibration beam 24. The extraction electrode is connected to one end of one extraction electrode within the surface, and the other end of the one extraction electrode is connected to the second region 30 side end of the surface excitation electrode 70 of the third region 32 in the first vibration beam 24. It has the structure connected to.

  The extraction electrode 115 drawn out from the end of the surface excitation electrode 70 in the third region 32 of the first vibration beam 24 on the base end portion 22 side is drawn around the surface side of the base end portion 22 so that the second vibration beam 26 The inner surface excitation electrode 82 of the third region 32 is connected to the proximal end 22 side end. When the extraction electrode 115 is routed from the front surface to the inner surface, disconnection can be prevented by arranging a metal pattern also on the fork 92b of the vibration beams 24 and 26.

  The extraction electrode 116 drawn from the end of the inner surface excitation electrode 82 of the third region 32 in the second vibration beam 26 on the second region 30 side is drawn to the back side of the second vibration beam 26 and branched into two branches. The One of the branched extraction electrodes 116 is connected to the third region 32 side end of the back surface excitation electrode 64 of the second region 30 in the second vibration beam 26, and the other is connected to the third region 32 of the second vibration beam 26. The outer surface excitation electrode 84 is connected to the end of the second region 30 side.

  The extraction electrode 117 extracted from the end of the outer surface excitation electrode 84 in the third region 32 of the second vibration beam 26 on the side of the base end 22 is drawn to the back side of the base end 22 and then the first vibration. The beam 24 is connected to the proximal end 22 side end of the back surface excitation electrode 72 in the third region 32 of the beam 24. When the extraction electrode 117 is routed from the outer side excitation electrode 84 to the back surface side of the base end portion 22, the metal pattern is also formed by arranging the metal pattern on the surface 90 d of the connection portion 18 in the base end portion 22. The disconnection at the time can be prevented.

  In other words, the double tuning fork type piezoelectric vibrating piece 10 having the above-described configuration is, in other words, the front surface excitation electrodes 54 and 62 or the back surface excitation electrodes 56 and 64 in the second region 30 and the inner surface excitation in the first region 28 or the third region 32. Lead electrodes 101, 111, 107, and 116 (center end lead electrodes) that connect the electrodes 42, 50, 74, and 82 and the outer surface excitation electrodes 44, 52, 76, and 84, and the back surface excitation electrode of the first region 28 Lead electrodes 113, 104, 114, 105 connecting the surface excitation electrodes 70, 78 in the 40, 48 or third region 32 with the inner surface excitation electrodes 58, 66 and the outer surface excitation electrodes 60, 68 in the second region 30. It can be said that it has (end part center extraction electrode).

  With the above-described configuration, the inner surface excitation electrodes 58 and 66 and the outer surface excitation electrodes 60 and 68 in the second region 30 have the back surface excitation electrodes 40 and 48 in the first region 28, and the third The extraction electrodes 113, 104, 114, and 105 are routed so that both the surface excitation electrodes 70 and 78 in the region 32 can be electrically connected. For this reason, at the stage of forming the metal pattern, a mask position required for vapor deposition, etching, etc., is shifted. For example, the inner surface excitation electrode 58 of the second region 30 in the first vibration beam 24 on the surface of the piezoelectric element plate. Even when a disconnection occurs in the extraction electrode 114 connected to the inner surface excitation electrode 58, the extraction electrode 114 connected to the outer surface excitation electrode 60 of the second region 30 in the first vibration beam 24, A voltage having the same potential as that of the outer surface excitation electrode 60 is applied through the outer surface excitation electrode 60 and the extraction electrode 113 routed to the back surface side, which may cause an increase in CI value, oscillation failure, and the like. It becomes possible to suppress.

  That is, when the exposure mask is shifted downward with respect to an appropriate position in FIG. 1B, the end of the extraction electrode 114 near the outer surface is located between the surface of the vibration beam 24 and the outer surface. Since the boundary is not reached, the end near the outer surface of the extraction electrode 114 and the outer surface excitation electrode 60 are not connected.

  On the other hand, since the end near the inner surface of the extraction electrode 114 approaches the boundary between the surface of the vibration beam 24 and the inner surface, the end near the outer surface of the extraction electrode 114 and the inner surface excitation electrode 58 are connected. In the configuration, the connection is assured by the same action in the vibration beam 26.

  Accordingly, even when the mask is misaligned due to such a configuration, the excitation electrode 64 on the back surface of the second region 30 of the vibration beam 26 is changed from the excitation electrode 62 on the front surface of the second region 30 of the vibration beam 26. It is possible to ensure a conduction path up to.

  Note that the connection portion 14 at the base end portions 12 and 22 is connected to the inner surface excitation electrodes 42, 50, 74, and 82 and the outer surface excitation electrodes 44, 52, 76, and 84 in the first region 28 and the third region 32. , 18 surfaces 90a to 90d and the forks 92a and 92b, the risk of disconnection due to the influence of mask misalignment or the like can be reduced.

  In the above embodiment, it has been described that the cross-sectional shapes of the vibration beams 24 and 26 are rectangular. However, grooves along the longitudinal direction of the vibration beam may be provided on the front and back surfaces of the vibration beams 24 and 26. When such grooves are provided, the cross-sectional shapes of the vibration beams 24 and 26 form an H-shaped body as shown in FIG. 3 is a diagram showing a cross-sectional shape of the second region 30 when the vibration beam 24 is viewed from the base end portion 12 side. In the cross-sectional view shown in FIG. 3, for example, the cross section of the inner side surface and the outer side surface is expressed by a straight line, but this is because it is schematically expressed, and may be a shape having an uneven surface. That is, when the double tuning fork type piezoelectric vibrating piece 10 is formed by using the wet etching technique, the erosion speed of the piezoelectric material varies depending on the crystal axis direction, so that actually, for example, uneven surfaces are generated on the inner surface and the outer surface. Because there are cases.

  When the cross-sectional shape of the vibration beams 24 and 26 is H-shaped, vibration loss at the time of voltage application is reduced, so that improvement of the CI value accompanying the downsizing of the double tuning fork type piezoelectric vibrating piece can be suppressed. For this reason, even with a miniaturized double tuning fork type piezoelectric vibrating piece, it is possible to provide highly accurate performance.

  Moreover, in the said embodiment, surface excitation electrode 54,62,70,78 or back surface excitation electrode 40,48,56,64, inner surface excitation electrode 42,50,58,66,74,82, and outer surface excitation electrode The lead electrodes 101, 111, 114, 105, 113, 104, 107, 116 that connect both of the electrodes 44, 52, 60, 68, 76, 84 are the surface excitation electrodes 54, 62, 70, 78 or the back surface excitation electrodes. The extraction electrodes 101, 111, 114, 115, 113, 104, 107, and 116 extracted from 40, 48, 56, and 64 are branched into one fork, and the extraction electrodes 101, 111, and 114 are branched. , 115, 113, 104, 107, 116 are respectively arranged on the inner surface excitation electrodes 42, 50, 58, 66, 74, 82 and the outer surface excitation electrodes 44, 52, It described that to connect to the 0,68,76,84. However, in manufacturing the double tuning fork type piezoelectric vibrating piece 10 according to the present invention, naturally, two extraction electrodes are extracted from the surface excitation electrodes 54, 62, 70, 78 or the back surface excitation electrodes 40, 48, 56, 64, Each of them may be connected to the inner surface excitation electrodes 42, 50, 58, 66, 74, 82 and the outer surface excitation electrodes 44, 52, 60, 68, 76, 84. However, when an extraction electrode having a configuration in which one extraction electrode is bifurcated is adopted, for example, the extraction electrode is used because it is a configuration that also serves as a conductor path to the outer surface excitation electrode 44 and the inner surface excitation electrode 42. It is possible to reduce the area to be formed, which is effective for downsizing.

It is a figure which shows the structure of the double tuning fork type piezoelectric vibrating piece which concerns on embodiment. It is a figure which shows the structure of the inner surface of the vibration beam in the double tuning fork type piezoelectric vibrating piece which concerns on embodiment. It is a figure which shows the application form of the cross-sectional shape of a vibration beam. It is a figure which shows the structure of the conventional double tuning fork type piezoelectric vibrating piece.

Explanation of symbols

  10 ......... Twin tuning fork type piezoelectric vibrating piece, 12 ......... Base end, 14 ......... Connecting portion, 15 ......... Constriction, 16 ......... Fixing portion, 18 ......... Connecting portion, 20 ......... Fixing part, 22 ......... Base end part, 24 ......... vibration beam (first vibration beam), 26 ......... vibration beam (second vibration beam), 28 ......... first region, 30 ......... first 2 region 32... 3rd region 34... Input / output electrode (first input / output electrode) 36... Input / output electrode (second input / output electrode) 38, 46, 54, 62 , 70, 78... Surface excitation electrode, 40, 48, 56, 64, 72, 80... Back surface excitation electrode, 44, 52, 60, 68, 76, 84. 50, 58, 66, 74, 82... Inner surface excitation electrodes, 90a to 90d... Surface, 92a, 92b. 2,103,104,105,106,107,108,110,111,112,113,114,115,116,117 ......... extraction electrode.

Claims (4)

Each of the vibration beams has a pair of base end portions and two vibration beams stretched in parallel between the base end portions, and each of the vibration beams is divided into three that are sequentially arranged in the extending direction of the vibration beam. As an excitation region, two end regions adjacent to the base end portion and a central region sandwiched between the two end regions are provided, and each of the two vibration beams is provided in the excitation region. The surface aligned in the same plane when viewed side by side, the back surface positioned behind the surface, the inner surface facing between the two vibration beams, and the direction in which the space is positioned A double tuning fork-type piezoelectric vibrating piece in which an excitation electrode is formed on the outer surface facing the opposite direction;
A center end lead connected from one excitation electrode formed on the front surface or the back surface in the center region to two excitation electrodes disposed on the inner surface and the outer surface in either one of the two end regions Electrodes,
An end center lead connected to one excitation electrode formed on the front or back surface in either one of the two end regions and two excitation electrodes arranged on the inner surface and the outer surface in the center region A double tuning fork type piezoelectric vibrating piece having an electrode. The double tuning fork type piezoelectric vibrating piece according to claim 1,
Each of the central end extraction electrode and the end central extraction electrode is formed by bifurcating one extraction electrode extracted from an excitation electrode formed on the front surface or the back surface into the inner surface or the outer surface. A double tuning fork type piezoelectric vibrating piece connected to an excitation electrode formed on The double tuning fork type piezoelectric vibrating piece according to claim 1 or 2,
When the excitation electrode formed on the front surface or the back surface in the end region and the excitation electrode formed on the inner surface or the outer surface in the end region are connected by the extraction electrode, the base end A metal pattern straddling a surface located in a direction intersecting the longitudinal direction of the vibration beam is provided, and the metal pattern is also connected to an excitation electrode formed on the inner surface or the outer surface. Tuning fork type piezoelectric vibrating piece. The double tuning fork type piezoelectric vibrating piece according to any one of claims 1 to 3,
A double tuning fork type piezoelectric vibrating piece characterized in that a concave groove is provided on the front surface and the back surface of the vibrating beam, and the sectional shape of the vibrating beam is H-shaped.

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