JP2015027005A - Tuning fork-type vibration piece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tuning fork-type vibration piece arranged so that a rapid change in rigidity in an arm part can be suppressed readily.SOLUTION: A tuning fork-type vibration piece (100) comprises: a base part (110); arm parts (120) arrayed in parallel along a predetermined direction, extending from the base part with their one ends joined to the base part; a first electrode film (131) directly provided on one of opposing principal surfaces of each arm part, extending along a predetermined direction, and made of a conductive material; a first piezoelectric material film (132) provided on the surface of the first electrode film, and extending along the predetermined direction; and a second electrode film (133) provided on the surface of the first piezoelectric material film, extending along the predetermined direction, and made of a conductive material. The first electrode film is formed to become longer than the first piezoelectric material film on the side of the other end of the arm part; and the first piezoelectric material film is formed to become longer than the second electrode film on the side of the other end of the arm part.

Description

  The present invention relates to a tuning-fork type vibrating piece having a plurality of arms.

  A tuning fork vibrator having a plurality of arm portions, a base portion to which one end of each arm portion is connected, and a piezoelectric element formed on one main surface of the arm portion is known. The piezoelectric element is formed by a lower electrode film formed on the arm portion, a piezoelectric film formed on the lower electrode film, and an upper electrode film formed on the piezoelectric film. In such a tuning fork vibrator, the piezoelectric film expands and contracts when an electric field is applied between the upper electrode film and the lower electrode film, and the arm portion bends and vibrates in the thickness direction. Further, in such a tuning fork type vibrator, a decrease in temperature characteristics due to miniaturization is suppressed, the number of arm portions is an odd number, and adjacent arm portions alternately vibrate up and down to increase the Q value.

  On the other hand, it is known that when the area of the upper electrode film and the lower electrode film is reduced, the vibration efficiency is deteriorated, and when the area of the upper electrode film and the lower electrode film is increased, the electric parallel capacitance is increased. For the purpose of balancing these, the piezoelectric film is provided so as to cover the base half of the arm portion together with the upper electrode film and the lower electrode film, and the tip side portion of the arm portion is not covered by the piezoelectric film. Formed. However, the bending stiffness against vibration in the thickness direction of the vibrating arm including the piezoelectric film and the upper and lower electrode films changes abruptly at the boundary between the area covered with the piezoelectric film and the area not covered in the arm portion. As a result, an unnecessary vibration mode is generated, and the Q value cannot be sufficiently increased.

  With respect to such a problem, in Patent Document 1, the lower electrode film and the piezoelectric film are formed in the length direction of the arm part to the tip of the arm part, and the lower electrode film and the piezoelectric film have the same length. Is formed. The upper electrode film extends to the middle of the arm part in the length direction of the arm part and is formed shorter than the lower electrode film or the piezoelectric film. Thus, it is shown that the rigidity of the arm portion is prevented from changing rapidly.

JP 2011-223489 A

  However, as described in Patent Document 1, extending the lower electrode film and the piezoelectric film to the distal end side of the arm part worsens the balance between the vibration efficiency and the electric parallel capacitance than the conventional tuning fork type vibrating piece. Will end up.

  An object of the present invention is to provide a tuning fork type vibration piece in which a sudden change in rigidity in an arm portion is easily suppressed.

  In the tuning-fork type resonator element according to the first aspect, a base, an arm that is parallel to a predetermined direction and has one end connected to a plurality of extending bases, and a predetermined direction provided directly on one main surface of each arm A first electrode film made of a conductive material, a first piezoelectric film provided on a surface of the first electrode film and extending in a predetermined direction, and a conductive material provided on a surface of the first piezoelectric film and extended in a predetermined direction The first electrode film is formed longer on the other end side of the arm portion than the first piezoelectric film, and the first piezoelectric film is formed on the other end side of the arm portion. It is formed longer than the two-electrode film.

  In the tuning fork type resonator element according to the second aspect, in the first aspect, the second electrode film is formed to have a constant width from one end side of the arm portion to a predetermined position, and from the predetermined position to the other end of the arm portion. The width is formed narrower as it extends toward the end side.

  In the tuning fork type resonator element according to the third aspect, in the second aspect, the first piezoelectric film and the first electrode film are also formed to have a predetermined width up to a predetermined position in the same manner as the second electrode film. The width is formed narrower as it extends from the other end side of the arm portion.

  In a tuning fork type resonator element according to a fourth aspect, in the first to third aspects, a third electrode film that is provided directly on the other main surface of each arm portion and extends in a predetermined direction and is made of a conductive material, and a third electrode film A second piezoelectric film provided on the surface of the second piezoelectric film and extending in a predetermined direction; and a fourth electrode film provided on the surface of the second piezoelectric film and extending in the predetermined direction and made of a conductive material.

In the tuning-fork type resonator element according to the fifth aspect, in the first to fourth aspects, the first piezoelectric film is a film containing any one of ZnO, AlN, PZT, LiNbO ₃ and KNbO ₃ .

  In the tuning fork type resonator element according to the sixth aspect, in the first to fifth aspects, the base portion and the arm portion are X-cut quartz.

  In the tuning-fork type resonator element according to the seventh aspect, in the first to sixth aspects, an odd number of three or more arm portions are arranged, and among the arm portions, the odd-numbered arm portions counted from the end are arranged. The first electrode film of the first arm part and the second electrode film of the second arm part are electrically connected to each other when one arm part is used and the evenly arranged arm part is the second arm part. In addition, the second electrode film of the first arm portion and the first electrode film of the second arm portion are electrically connected to each other.

  According to the tuning fork type resonator element of the present invention, it is possible to easily suppress a sudden change in rigidity in the arm portion.

FIG. 3A is a plan view of the tuning fork type vibrating piece 100. (B) is AA sectional drawing of Fig.1 (a). (A) is BB sectional drawing of Fig.1 (a). (B) is an enlarged view of a portion corresponding to a dotted line 161 in FIG. 2 (a) of a conventional tuning fork type vibrating piece. FIG. 2C is an enlarged view of a dotted line 161 in FIG. FIG. 3A is a cross-sectional view of the tuning fork type vibrating piece 200. (B) is CC sectional drawing of Fig.3 (a). FIG. 4A is a plan view of a tuning fork type vibrating piece 300. FIG. 6B is a plan view of the tuning fork type vibrating piece 400. 4 is a cross-sectional view of a vibrating device 500. FIG.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings. It should be noted that the scope of the present invention is not limited to these forms unless otherwise specified in the following description.

(First embodiment)
<Configuration of Tuning Fork Type Vibrating Piece 100>
FIG. 1A is a plan view of the tuning fork type vibrating piece 100. The tuning fork resonator element 100 includes a base portion 110, three arm portions 120 connected to the base portion 110, and a piezoelectric element 130 formed on each arm portion 120. In the following description, the direction in which the arm part 120 extends will be described as the Y-axis direction, the direction in which the arm parts 120 are arranged will be the X-axis direction, and the direction perpendicular to the X-axis direction and the Y-axis direction will be described as the Z-axis direction.

  Each arm 120 is formed to extend in the Y-axis direction, and an end on the −Y-axis side is connected to the base 110 and is formed integrally with the base 110. The base 110 and the arm 120 are made of a piezoelectric material or a non-piezoelectric material having predetermined vibration characteristics. As the piezoelectric material, for example, crystal, lithium tantalate, lithium niobate, lithium borate, barium titanate, or the like is used. As the crystal, an X-cut crystal is used, but an AT-cut, a Z-cut, or the like may be used. Silicon, quartz glass, or the like is used as the non-piezoelectric material. Each arm portion 120 has a main surface on the + Z-axis side and a surface on the −Z-axis side, and a piezoelectric element 130 is formed on the main surface on the + Z-axis side. The piezoelectric element 130 is formed on the first electrode film 131 formed on the surface of the arm 120, the first piezoelectric film 132 formed on the first electrode film 131, and the first piezoelectric film 132. And the second electrode film 133. The first electrode film 131, the first piezoelectric film 132, and the second electrode film 133 are formed so that the width in the X-axis direction is substantially equal, but the first electrode film 131 is the longest at the end on the + Y-axis side. Then, the first piezoelectric film 132 is long and the second electrode film 133 is shortest. In FIG. 1A, electrodes are also formed on the base 110, but these electrodes are not shown.

  FIG.1 (b) is AA sectional drawing of Fig.1 (a). Hereinafter, for the sake of explanation, the arm part on the −X axis side is referred to as an arm part 120a, the central arm part is referred to as an arm part 120b, and the arm part on the + X axis side is referred to as an arm part 120c. The first electrode film 131 formed on the arm portion 120a is referred to as a first electrode film 131a, the first piezoelectric film 132 is referred to as a first piezoelectric film 132a, and the second electrode film 133 is referred to as a second electrode film 133a. Similarly, the first electrode film 131b, the first piezoelectric film 132b, and the second electrode film 133b are formed on the arm part 120b, and the first electrode film 131c, the first piezoelectric film 132c, and the like are formed on the arm part 120c. A second electrode film 133c is formed. At this time, the connection terminal 134 a and the connection terminal 134 b are formed on the base 110. The connection terminal 134b is electrically connected to the second electrode film 133a, the first electrode film 131b, and the second electrode film 133c. The connection terminal 134a is connected to the first electrode film 131a, the second electrode film 133b, and the first electrode film 133b. It is electrically connected to the electrode film 131c. In the tuning fork type vibrating piece 100, when an alternating voltage is applied between the connection terminal 134a and the connection terminal 134b, the arm part 120b and the arm part 120a and the arm part 120c are staggered in the Z-axis direction. Vibrate.

Fig.2 (a) is BB sectional drawing of Fig.1 (a). The first electrode film 131 and the second electrode film 133 are made of a conductive material, and are formed, for example, by forming a chromium film and forming a gold film on the surface thereof. The first piezoelectric film 132 is made of, for example, ZnO, AlN, PZT, LiNbO ₃ , or KNbO ₃ . The thickness TA of the first electrode film 131 is, for example, 100 nm, the thickness TB of the first piezoelectric film 132 is 1 μm, and the thickness TC of the second electrode film 133 is formed to 100 nm. That is, the first piezoelectric film 132 is formed to be the thickest.

  FIG. 2B is an enlarged view of a portion corresponding to the dotted line 161 in FIG. 2A of the conventional tuning fork type resonator element. In the conventional tuning fork type resonator element, the first electrode film 131, the first piezoelectric film 132, and the second electrode film 133 are formed so that the lengths on the + Y-axis side ends are equal. For this reason, the rigidity of the arm portion 120 changes abruptly at the boundary (arrow 162) between the region where the piezoelectric element 130 is formed and the region where the piezoelectric element 130 is not formed, and an unnecessary vibration mode is generated. This unnecessary vibration mode is due to the vibration of the arm 120 so that it is bent at the boundary indicated by the arrow 162 of the first piezoelectric film 132. When the arm portion 120 is vibrated so as to be bent, the temperature rises, the internal loss increases, and the Q value cannot be sufficiently increased.

  FIG.2 (c) is an enlarged view of the dotted line 161 of Fig.2 (a). In the tuning fork type vibrating piece 100, the first piezoelectric film 132 extends from the end of the second electrode film 133 on the base 110 side to the position of the arrow 163a that is the + Y-axis side end of the second electrode film 133. 131 and the second electrode film 133. If the first piezoelectric film 132 is formed longer than the second electrode film 133 by the length LA1 at the end on the + Y-axis side, the position of the arrow 163b that becomes the length LA1 in the + Y-axis direction from the arrow 163a Until then, the second electrode film 133 is not formed, and the thickness of the piezoelectric element 130 becomes thinner than the −Y-axis side of the arrow 163a. Further, assuming that the first electrode film 131 is formed longer than the first piezoelectric film 132 by the length LA2 at the end on the + Y axis side, the second electrode is in the range of the length LA2 from the arrow 163b to the + Y axis direction. The film 133 and the first piezoelectric film 132 are not formed, and the thickness of the piezoelectric element 130 is thinner than the −Y axis side of the arrow 163b. As described above, in the tuning fork type vibrating piece 100, the total thickness of the arm portion 120 and the piezoelectric element 130 gradually decreases toward the + Y-axis side in the vicinity of the tip of the arm portion 120 on the + Y-axis side. Accordingly, the change in the rigidity of the arm 120 also changes stepwise, so that the rapid change in the rigidity of the arm 120 described in FIG. 2B is suppressed, and the arm 120 is bent. Vibration can be suppressed. For this reason, in the tuning fork type vibrating piece 100, generation of unnecessary vibration modes and reduction of the Q value can be suppressed.

  Further, in the tuning fork type vibrating piece 100, the length LA1 and the length LA2 are further expanded, the first electrode film 131 is formed to the tip of the arm part 120 on the + Y axis side, and the second electrode film 133 is the arm part 120. The tip of the first piezoelectric film 132 on the + Y axis side is intermediate between the tip of the first electrode film 131 on the + Y axis side and the tip of the second electrode film 133 on the + Y axis side. It may be formed as follows. Thereby, the change of the rigidity of the arm part 120 can be changed more gently.

(Second Embodiment)
In the tuning fork type resonator element, a piezoelectric element may be formed not only on the surface on the + Z axis side but also on the surface on the −Z axis side. A tuning fork type vibrating piece 200 in which piezoelectric elements are formed on both the + Z-axis side and the −Z-axis side of the arm will be described below. Further, portions similar to those of the tuning fork type vibrating piece 100 are denoted by the same reference numerals as those of the tuning fork type vibrating piece 100, and description thereof is omitted.

<Configuration of Tuning Fork Type Vibrating Piece 200>
FIG. 3A is a cross-sectional view of the tuning fork type vibrating piece 200. The tuning fork-type vibrating piece 200 includes a base 110, three arm portions 120 connected to the base portion 110, a piezoelectric element 130 formed on the surface of each arm portion 120 on the + Z-axis side, and each arm portion 120. And the piezoelectric element 230 formed on the surface on the Z-axis side. The piezoelectric element 230 is formed on the third electrode film 231 formed on the surface of the arm 120, the second piezoelectric film 232 formed on the third electrode film 231, and the second piezoelectric film 232. And a fourth electrode film 233. The third electrode film 231 has the same shape as the first electrode film 131 and is formed to overlap each other in the Z-axis direction, and the second piezoelectric film 232 has the same shape as the first piezoelectric film 132 and has the Z-axis. The fourth electrode films 233 are formed to have the same shape as the second electrode film 133 and overlap each other in the Z-axis direction.

  FIG.3 (b) is CC sectional drawing of Fig.3 (a). In the piezoelectric element 230, the third electrode film 231a formed on the arm part 120a, the fourth electrode film 233b of the arm part 120b, and the third electrode film 231c of the arm part 120c are electrically connected. These electrode films are electrically connected to the second electrode film 133a, the first electrode film 131b, and the second electrode film 133c of the piezoelectric element 130, and are further electrically connected to the connection terminal 134b. On the other hand, the fourth electrode film 233a formed on the arm part 120a of the piezoelectric element 230, the third electrode film 231b of the arm part 120b, and the fourth electrode film 233c of the arm part 120c are electrically connected to each other. The first electrode film 131a, the second electrode film 133b, and the first electrode film 131c of 130 are electrically connected and electrically connected to the connection terminal 134a.

  In each arm portion 120 of the tuning fork-type vibrating piece 200, when an alternating voltage is applied between the connection terminal 134a and the connection terminal 134b, the piezoelectric element 130 formed on the + Z-axis side of each arm portion 120 extends. In this case, the piezoelectric element 230 formed on the −Z axis side contracts, and when the piezoelectric element 130 formed on the + Z axis side contracts, the piezoelectric element 230 formed on the −Z axis side expands. Each arm 120 vibrates in the Z-axis direction.

  In the tuning fork type resonator element 200, the piezoelectric element 230 formed on the −Z-axis side of the arm portion 120 is used to vibrate the arm portion 120, but the piezoelectric distortion generated by the vibration of the arm portion 120 is used as the piezoelectric element 230. It may be used as a piezoelectric thin film element for detection that outputs a converted electric charge. At this time, the piezoelectric element 230 may not be formed in the same shape as the piezoelectric element 130. When the piezoelectric element 230 is used as a piezoelectric thin film element for detection, the tuning fork type vibrating piece 200 is used as an acceleration detection element.

(Third embodiment)
In the tuning fork type resonator element, the planar shape of the end on the + Z-axis side of the piezoelectric element may be changed. Hereinafter, the tuning fork type vibrating piece 300 and the tuning fork type vibrating piece 400 in which the planar shape of the end on the + Z-axis side of the piezoelectric element is changed will be described. The same parts as those of the first embodiment and the second embodiment are denoted by the same reference numerals as those of the first embodiment and the second embodiment, and the description thereof is omitted.

<Configuration of Tuning Fork Type Vibrating Piece 300>
FIG. 4A is a plan view of the tuning fork type resonator element 300. The tuning fork type resonator element 300 includes a base portion 110, an arm portion 120, and a piezoelectric element 330 formed on the surface of the arm portion 120 on the + Z-axis side. The piezoelectric element 330 includes a first electrode film 331 formed on the surface of the arm portion 120, a first piezoelectric film 332 formed on the first electrode film 331, and a first electrode formed on the first piezoelectric film 332. A two-electrode film 333 is included. The piezoelectric element 330 is formed with a constant width from the base 110 side to the position of the arrow 164, and is formed so that the width becomes narrower from the arrow 164 toward the + Y axis side. Further, on the + Y-axis side from the arrow 164, the + Y-axis side end of the second electrode film 333 is formed on the −Y-axis side with respect to the + Y-axis side ends of the first electrode film 331 and the first piezoelectric film 332. . Further, the + Y-axis side end of the first electrode film 331 is formed on the + Y-axis side with respect to the + Y-axis side end of the first piezoelectric film 332. Therefore, the + Y-axis side end of the piezoelectric element 330 is formed in a stepped shape as in FIG. Further, the end of the piezoelectric element 330 on the + Y axis side is formed such that the width in the X axis direction becomes narrower from the arrow 164 toward the + Y axis direction.

  In the tuning fork type vibrating piece 300, like the tuning fork type vibrating piece 100, the first piezoelectric film 332 is formed longer on the + Y-axis side than the second electrode film 333, so that the arm portion 120 vibrates so as to be bent. Can be suppressed. Further, since the width of the piezoelectric element 330 is gradually narrowed from the arrow 164 toward the + Y-axis direction, the area where the piezoelectric element 330 is formed gradually decreases from the position of the arrow 164 toward the + Y-axis side. . This also changes the rigidity of the arm part 120 in a stepwise manner in the Y-axis direction, so that a sudden change in the rigidity of the arm part 120 can be suppressed and the arm part 120 can be prevented from vibrating so as to be bent. . As a result, generation of unnecessary vibration modes and a reduction in the Q value are suppressed in the tuning fork type vibrating piece 300.

<Configuration of Tuning Fork Type Vibrating Piece 400>
FIG. 4B is a plan view of the tuning fork type vibrating piece 400. The tuning fork-type vibrating piece 400 includes a base 110, an arm 120, and a piezoelectric element 430 formed on the surface of the arm 120 on the + Z-axis side. The piezoelectric element 430 includes a first electrode film 431 formed on the surface of the arm 120, a first piezoelectric film 432 formed on the first electrode film 431, and a first electrode formed on the first piezoelectric film 432. A two-electrode film 433 is included. The first electrode film 431 has the same shape as the first electrode film 131 (see FIG. 1A), and the first piezoelectric film 432 has the same shape as the first piezoelectric film 132 (see FIG. 1A). It is formed to become. In the region on the + Y-axis side from the arrow 165 in FIG. 4B, the + Y-axis side end of the second electrode film 433 is −Y than the + Y-axis side ends of the first electrode film 431 and the first piezoelectric film 432. It is formed on the shaft side. Further, the + Y-axis side end of the first electrode film 431 is formed closer to the + Y-axis side end than the + Y-axis side end of the first piezoelectric film 432. Therefore, the end on the + Y-axis side of the piezoelectric element 430 is formed in a step shape like the piezoelectric element 130 in FIG. Further, the second electrode film 433 of the piezoelectric element 430 is formed to have a constant width from the base 110 side to the position of the arrow 165 and to be narrowed from the arrow 165 toward the + Y axis side. For this reason, the change in rigidity of the arm portion 120 gradually changes from the arrow 165 to the + Y axis side of the second electrode film 433 toward the + Y axis side. An abrupt change can be suppressed, the arm portion 120 can be prevented from vibrating so as to be bent, and generation of unnecessary vibration modes and a reduction in the Q value can be suppressed.

(Fourth embodiment)
The tuning fork type vibrating piece shown in the first to third embodiments is housed in a package and formed as a vibrating device. Hereinafter, such a vibrating device 500 will be described.

<Configuration of vibrating device 500>
FIG. 5 is a cross-sectional view of the vibration device 500. The vibration device 500 includes a package 510, a tuning fork type vibrating piece 100 placed in the package 510, and a lid plate 520 that seals the tuning fork type vibrating piece 100 in the package 510. The surface of the package 510 on the + Z-axis side is formed with a recess 511 that is recessed toward the −Z-axis, and the tuning fork type vibrating piece 100 is placed in the recess 511. The recess 511 is sealed by the lid plate 520.

  The package 510 is formed of, for example, a first layer 510a and a second layer 510b formed on the surface of the first layer 510a on the + Z-axis side. A pair of mounting electrodes 512 that are electrically connected to the printed circuit board or the like when the vibration device 500 is mounted on the printed circuit board or the like are formed on the surface on the −Z-axis side of the first layer 510a. A pair of connection electrodes 513 is formed on the surface on the + Z axis side. The connection electrode 513 and the mounting electrode 512 are electrically connected to each other through a through electrode 514 that penetrates the first layer 510a. The second layer 510b is a layer having a central region that penetrates in the Z-axis direction, and is a layer that forms the side surface of the recess 511.

  A pair of connection electrodes 513 is formed in the recess 511. The tuning fork type vibrating piece 100 is connected to the recess 511 by electrically connecting the connection terminal 134a and the connection terminal 134b (see FIG. 1B) to the pair of connection electrodes 513 through the conductive adhesive 532, respectively. Placed. The concave portion 511 on which the tuning fork type vibrating piece 100 is placed is sealed by placing the lid plate 520 on the surface on the + Z-axis side of the second layer 510 b via the sealing material 531.

  As described above, the optimal embodiment of the present invention has been described in detail. However, as will be apparent to those skilled in the art, the present invention can be implemented with various modifications and variations within the technical scope thereof.

DESCRIPTION OF SYMBOLS 100, 200, 300, 400 ... Tuning fork type vibration piece 110 ... Base part 120, 120a, 120b, 120c ... Arm part 130, 230, 330, 430 ... Piezoelectric element 131, 131a, 131b, 131c, 331, 431 ... First electrode Films 132, 132a, 132b, 132c, 332, 432 ... first piezoelectric films 133, 133a, 133b, 133c, 333, 433 ... second electrode films 134a, 134b ... connection terminals 231, 231a, 231b, 231c ... third Electrode films 232, 232a, 232b, 232c ... 2nd piezoelectric film 233, 233a, 233b, 233c ... 4th electrode film 500 ... Vibration device 510 ... Package 510a ... 1st layer 510b ... 2nd layer 511 ... Recessed 512 ... Mounting Electrode 513 ... Connection electrode 520 ... Head plate 531 ... sealing material 532 ... conductive adhesive

Claims (7)

The base,
A plurality of arms extending in parallel in a predetermined direction and having one end connected to the base,
A first electrode film that is provided directly on one main surface of each arm and extends in the predetermined direction and is made of a conductive material;
A first piezoelectric film provided on a surface of the first electrode film and extending in the predetermined direction;
A second electrode film provided on the surface of the first piezoelectric film and extending in the predetermined direction and made of a conductive material,
The first electrode film is formed longer than the first piezoelectric film on the other end side of the arm part, and the first piezoelectric film is formed on the other end side of the arm part than the second electrode film. A tuning-fork type resonator element that is formed long.   The second electrode film is formed to have a constant width from one end side of the arm portion to a predetermined position, and the width is reduced as it extends from the predetermined position to the other end side of the arm portion. The tuning fork type vibrating piece according to claim 1.   Similarly to the second electrode film, the first piezoelectric film and the first electrode film are also formed to have a certain width up to the predetermined position, and from the predetermined position to the other end side of the arm portion. The tuning fork type resonator element according to claim 2, wherein the tuning fork type resonator element is formed to have a narrower width as it extends. A third electrode film provided directly on the other main surface of each arm and extending in the predetermined direction and made of a conductive material;
A second piezoelectric film provided on the surface of the third electrode film and extending in the predetermined direction;
4. The tuning fork type resonator element according to claim 1, further comprising: a fourth electrode film provided on a surface of the second piezoelectric film and extending in the predetermined direction and made of a conductive material. 5. 5. The tuning-fork type resonator element according to claim 1, wherein the first piezoelectric film is a film containing any one of ZnO, AlN, PZT, LiNbO _3, and KNbO ₃ .   The tuning fork type resonator element according to any one of claims 1 to 5, wherein the base portion and the arm portion are X-cut quartz. The arms are arranged with an odd number of 3 or more,
Among the arm portions, the arm portions arranged oddly from the end are first arm portions, and the arm portions arranged evenly are second arm portions,
The first electrode film of the first arm and the second electrode film of the second arm are electrically connected to each other, and the second electrode film of the first arm and the second The tuning fork type vibrating piece according to any one of claims 1 to 6, wherein the first electrode film of the arm portion is electrically connected to each other.