Piezoelectric vibrator

Abstract

To provide a piezoelectric vibrator which is capable of obtaining desired vibration and has a stable structure.SOLUTION: A piezoelectric vibrator 10 comprises a plurality of piezoelectric body parts 110, a plurality of upper electrodes 130, a metal plate 150, and an insulation adhesive 132. Each of the piezoelectric body parts 110 extends in a vertical direction. A slit 106 is formed between the piezoelectric body parts 110. Each of the upper electrodes 130 is formed in an upper end of the piezoelectric body part 110. All the upper electrodes 130 are adhered to the metal plate 150 by the insulation adhesive 132. The metal plate 150 is conducted with all the upper electrodes 130 and supports the piezoelectric body part 110 via the insulation adhesive 132 and the upper electrode 130. The insulation adhesive 132 is present only in a region on an upper side of the slit 106, the region being 15% or less as large as a size of the slit 106 in the vertical direction.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a piezoelectric vibrator. [Background technology]

[0002] Patent Document 1 discloses an ultrasonic vibrator that includes a piezoelectric element in which a plurality of pillars are arranged.

[0003] In the ultrasonic vibrator of Patent Document 1, the pillars are made by forming cuts from the back side of a substantially circular ceramic plate that serves as the piezoelectric element. The cuts do not reach the front side of the ceramic plate, and the pillars are connected to each other. In other words, the piezoelectric element has a so-called half-cut structure.

[0004] In the ultrasonic vibrator of Patent Document 1, the pillar portion is composed of a plurality of irregularly shaped non-rectangular pillar portions located on the outer periphery of the piezoelectric element when viewed from the back of the piezoelectric element, and a plurality of rectangular pillar portions surrounded by these irregularly shaped pillar portions. At least some of the irregularly shaped pillar portions are weaker than the rectangular pillar portions. Therefore, in the ultrasonic vibrator of Patent Document 1, the piezoelectric element is partially reinforced by filling the spaces between the irregularly shaped pillar portions with resin.

[0005] In the ultrasonic vibrator of Patent Document 1, a front electrode layer and a back electrode layer are formed on the front and back surfaces of the piezoelectric element, respectively. Furthermore, copper foil is adhered to the back electrode layer using an adhesive (conductive adhesive) containing a conductive filler. The copper foil is used as a common electrode for the irregular-shaped column portion and the rectangular column portion. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-155900 Summary of the Invention [Problem to be solved by the invention]

[0007] In the ultrasonic vibrator of Patent Document 1, the spaces between the irregular-shaped columnar portions are filled with resin. In other words, in the ultrasonic vibrator of Patent Document 1, the notches formed in the piezoelectric element are partially filled with resin. Therefore, there is a problem in that unnecessary vibrations are generated when the piezoelectric element is vibrated.

[0008] The above problem would not occur if the gaps between the irregularly shaped columns were not filled with resin. However, in this case, the piezoelectric element may become structurally unstable. In particular, if a full-cut structure is assumed in which the cuts made in the ceramic plate reach the front surface of the ceramic plate, the piezoelectric element is likely to become structurally unstable.

[0009] Furthermore, in the ultrasonic vibrator of Patent Document 1, the copper foil is bonded to the back electrode layer using a conductive adhesive, but there is also the problem that the adhesive strength of the conductive adhesive is weak.

[0010] An object of the present invention is to provide a piezoelectric vibrator that can obtain a desired vibration and has a stable structure. [Means for solving the problem]

[0011] The present invention provides a first piezoelectric vibrator including a plurality of piezoelectric portions, a plurality of upper electrodes, a metal plate, and an insulating adhesive, Each of the piezoelectric portions extends in the vertical direction, A slit is formed between the piezoelectric portions, The upper electrodes are formed on the upper ends of the piezoelectric portions, all of the upper electrodes are bonded to the metal plate by the insulating adhesive; the metal plate is electrically connected to all of the upper electrodes and supports the piezoelectric body portion via the insulating adhesive and the upper electrodes; The insulating adhesive is present only in an area above the slit, the area being 15% or less of the size of the slit in the vertical direction. A piezoelectric vibrator is provided.

[0012] Furthermore, the present invention provides a first piezoelectric vibrator as the second piezoelectric vibrator, Each of the piezoelectric body portions is a columnar body having a longitudinal direction in the vertical direction, The piezoelectric body portions are aligned in a first horizontal direction and a second horizontal direction that are perpendicular to the up-down direction and perpendicular to each other, The slits are formed in a grid pattern. A piezoelectric vibrator is provided.

[0013] Furthermore, the present invention provides a third piezoelectric vibrator, which is the first piezoelectric vibrator, the piezoelectric vibrator further comprises a plurality of lower electrodes, an additional metal plate, and an additional insulating adhesive; Each of the piezoelectric body portions is separated from the adjacent piezoelectric body portion, The lower electrodes are formed on the lower ends of the piezoelectric bodies, all of the lower electrodes are bonded to the additional metal plate by the additional insulating adhesive; the additional metal plate is electrically connected to all of the lower electrodes and supports the piezoelectric body portion via the additional insulating adhesive and the lower electrodes; The additional insulating adhesive is present only in an area below the slit, the area being 15% or less of the size of the slit in the vertical direction. A piezoelectric vibrator is provided.

[0014] Furthermore, the present invention provides a fourth piezoelectric vibrator, which is the first piezoelectric vibrator, The piezoelectric vibrator further includes a piezoelectric base and a lower electrode, the piezoelectric base is integrally formed with the piezoelectric body portion and connects lower ends of the piezoelectric body portions, The lower electrode is formed on the lower surface of the piezoelectric base. A piezoelectric vibrator is provided.

[0015] Furthermore, the present invention provides a fifth piezoelectric vibrator, which is the first piezoelectric vibrator, The metal plate is made of a material having a Young's modulus of 50 GPa or more. A piezoelectric vibrator is provided.

[0016] Furthermore, the present invention provides a sixth piezoelectric vibrator, which is the fifth piezoelectric vibrator, The area of ​​the metal plate is S [mm 2 ], and the plate thickness is T [mm], then formula 1 is satisfied. A piezoelectric vibrator is provided.

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[0017] In the piezoelectric vibrator of the present invention, the piezoelectric body is supported on a metal plate having a predetermined rigidity via an insulating adhesive and an upper electrode, thereby providing the piezoelectric vibrator with a stable structure.

[0018] In addition, in the piezoelectric vibrator of the present invention, the slits are not filled with resin. In addition, in the piezoelectric vibrator of the present invention, the insulating adhesive is present only in the region above the slit, in an area that is 15% or less of the vertical size of the slit. This allows the piezoelectric vibrator to suppress the generation of unnecessary vibrations and achieve desired vibrations. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a perspective view showing a piezoelectric vibrator according to a first embodiment of the present invention. [Figure 2] FIG. 2 is an exploded perspective view of the piezoelectric vibrator of FIG. [Figure 3] 2(a), 2(b), and 2(c) are diagrams for explaining a method for manufacturing the piezoelectric vibrator of FIG. [Figure 4] 3(a) and 3(b) are diagrams for explaining a method for manufacturing the piezoelectric vibrator of FIG. 1, and are diagrams for explaining a step subsequent to FIG. 3(c). [Figure 5] 1. (a), (b), and (c) are diagrams for explaining another method for manufacturing the piezoelectric vibrator of FIG. [Figure 6] 5(a), (b), and (c) are diagrams for explaining another method for manufacturing the piezoelectric vibrator of FIG. 1, and are diagrams for explaining steps subsequent to FIG. 5(c). [Figure 7] FIG. 2 is a front view showing the piezoelectric vibrator of FIG. [Figure 8] FIG. 10 is a perspective view showing a piezoelectric vibrator according to a second embodiment of the present invention. [Figure 9] FIG. 9 is an exploded perspective view of the piezoelectric vibrator of FIG. 8. DETAILED DESCRIPTION OF THE INVENTION

[0020] (First embodiment) 1, a piezoelectric vibrator 10 according to a first embodiment of the present invention includes a plurality of piezoelectric body portions 110, a plurality of upper electrodes 130, a metal plate 150, a plurality of lower electrodes 170, and an additional metal plate 190. As will be described later with reference to FIG. 7, the piezoelectric vibrator 10 further includes an insulating adhesive 132 and an additional insulating adhesive 172.

[0021] As can be seen from FIG. 2, each of the piezoelectric body parts 110 is columnar and extends in the vertical direction. In other words, each of the piezoelectric body parts 110 is a columnar body having a longitudinal axis in the vertical direction. In this embodiment, each of the piezoelectric body parts 110 is a square quadrangular prism when viewed along the vertical direction. In this embodiment, the vertical direction is the Z direction. The +Z direction is upward, and the -Z direction is downward.

[0022] As shown in Fig. 2, the piezoelectric body parts 110 are arranged in a first horizontal direction and a second horizontal direction that are perpendicular to the up-down direction and perpendicular to each other. In this embodiment, the first horizontal direction is the X direction, and the second horizontal direction is the Y direction. In this embodiment, six piezoelectric body parts 110 are arranged in each of the first horizontal direction and the second horizontal direction. However, the present invention is not limited to this. The number and arrangement of the piezoelectric body parts 110 can be set arbitrarily.

[0023] 2, slits 106 are formed between the piezoelectric body portions 110. In this embodiment, the slits 106 are formed in a lattice pattern. Each piezoelectric body portion 110 is separated from the adjacent piezoelectric body portion 110 by the slits 106. The slits 106 are not filled with resin.

[0024] As shown in FIG. 2, the upper electrodes 130 correspond to the piezoelectric body portions 110, respectively. Each of the upper electrodes 130 is formed on the upper end of the corresponding piezoelectric body portion 110. Similarly, the lower electrodes 170 correspond to the piezoelectric body portions 110, respectively, and each of the lower electrodes 170 is formed on the lower end of the corresponding piezoelectric body portion 110. In this embodiment, the upper electrodes 130 and the lower electrodes 170 are made of baked silver. However, the present invention is not limited to this. The upper electrodes 130 and the lower electrodes 170 may be formed by plating, for example.

[0025] As can be seen from FIGS. 1 and 2 , the metal plate 150 is attached to the upper surface of the upper electrode 130. Specifically, the metal plate 150 is bonded to the upper surfaces of all the upper electrodes 130 using an insulating adhesive 132 (see FIG. 7 ). In other words, all the upper electrodes 130 are bonded to the metal plate 150 with the insulating adhesive 132. When bonding, the metal plate 150 is pressed against the upper electrodes 130 to electrically connect them. This allows the metal plate 150 to be electrically connected to all the upper electrodes 130, forming an upper common electrode. Note that using the insulating adhesive 132 instead of a conductive adhesive can achieve higher adhesive strength than when a conductive adhesive is used. Furthermore, costs can be reduced compared to when a conductive adhesive is used. In addition, while a highly flexible adhesive exhibits high durability against vibrations during use of the piezoelectric vibrator 10, insulating adhesives 132 are often more flexible than conductive adhesives, providing a wider range of options.

[0026] As can be seen from FIG. 1, the metal plate 150 is adhered to all of the upper electrodes 130 using an insulating adhesive 132 (see FIG. 7), thereby supporting the piezoelectric body portion 110 via the insulating adhesive 132 and the upper electrodes 130. In order to stably support the piezoelectric body portion 110, the metal plate 150 has a predetermined rigidity. More specifically, the metal plate 150 is made of a material having a Young's modulus of 50 GPa or more. Examples of such materials include various metals such as copper, zinc, aluminum, and nickel, and alloys such as phosphor bronze, brass, and stainless steel. The metal plate 150 is formed using such a material so as to satisfy the following formula: Here, in the formula below, S [mm 2 ] represents the area of ​​the metal plate 150, and T [mm] represents the thickness of the metal plate 150. The metal plate 150, which is formed using a material having a Young's modulus of 50 GPa or more and has a dimensional ratio that satisfies the following formula, has a predetermined rigidity.

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[0027] Increasing the thickness T of the metal plate 15 allows the metal plate 15 to more stably support the piezoelectric body portion 110 and also facilitates the manufacture of the piezoelectric vibrator 10. Therefore, when stable support of the piezoelectric body portion 110 and ease of manufacture are required, it is preferable that the metal plate 150 satisfy the following formula.

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[0028] 1 and 2, additional metal plate 190 is attached to the lower surface of lower electrode 170. More specifically, additional metal plate 190 is bonded to the lower surfaces of all lower electrodes 170 using additional insulating adhesive 172 (see FIG. 7). In other words, all lower electrodes 170 are bonded to additional metal plate 190 by additional insulating adhesive 172. When bonded, additional metal plate 190 is pressed toward lower electrode 170, and additional metal plate 190 is electrically connected to all lower electrodes 170 to form a lower common electrode.

[0029] In this embodiment, the additional metal plate 190 is made of the same material as the metal plate 150. The additional metal plate 150 has a predetermined rigidity like the metal plate 150, and supports the piezoelectric body portion 110 via the additional insulating adhesive 172 and the lower electrode 170. The additional insulating adhesive 172 is made of the same material as the insulating adhesive 132. By using the additional insulating adhesive 172, the same effect as when the insulating adhesive 132 is used can be obtained.

[0030] As described above, in this embodiment, the piezoelectric body portion 110 is bonded to and supported by the metal plate 150 having a predetermined rigidity via the upper electrode 130 using the insulating adhesive 132. The piezoelectric body portion 110 is also bonded to and supported by the additional metal plate 190 having a predetermined rigidity via the lower electrode 170 using the additional insulating adhesive 172. This provides the piezoelectric vibrator 10 with a stable structure. Here, the term "stable structure" refers to the fact that the piezoelectric vibrator 10 can achieve desired vibration characteristics, has high structural reliability, and is easy to manufacture. Furthermore, in this embodiment, the piezoelectric body portion 110 is separated from adjacent piezoelectric body portions, and does not or is unlikely to generate unwanted vibrations. Therefore, the piezoelectric vibrator 10 can achieve desired vibrations.

[0031] Next, a method for manufacturing the piezoelectric vibrator 10 will be described with reference to FIGS.

[0032] First, as shown in Fig. 3(a), a piezoelectric plate 100 is prepared. The piezoelectric plate 100 has an upper surface 102 and a lower surface 104 that are perpendicular to the up-down direction. The thickness of the piezoelectric plate 100 is equal to the height of the piezoelectric portion 110. The piezoelectric plate 100 is made of, for example, lead zirconate titanate (PZT).

[0033] Next, silver paste (not shown) is applied to the upper surface 102 and the lower surface 104 of the piezoelectric plate 100, and then heated and sintered to form an upper electrode layer that will become the upper electrode (baked silver electrode) 130 (see Figures 1 and 2) and a lower electrode layer that will become the lower electrode (baked silver electrode) 170 (see Figures 1 and 2).

[0034] Next, the piezoelectric plate 100 is cut from the upper surface 102 side of the piezoelectric plate 100 using a dicing saw or the like to form slits 106 as shown in Fig. 3(b). At this time, the slits 106 do not reach the lower surface 104 of the piezoelectric plate 100 (half cut). The upper electrode layer is divided into multiple pieces to form upper electrodes 130.

[0035] The slits 106 are formed in a lattice pattern in plan view (see FIG. 2). More specifically, first, a plurality of slits 106 extending in the first horizontal direction and aligned at equal intervals in the second horizontal direction are formed, and then a plurality of slits 106 extending in the second horizontal direction and aligned at equal intervals in the first horizontal direction are formed. This results in a plurality of partial piezoelectric body portions 112 aligned in the first horizontal direction and the second horizontal direction. An upper electrode 130 is formed on the upper end of each of the partial piezoelectric body portions 112.

[0036] Next, an insulating adhesive 132 (see FIG. 7) is applied to the upper surface of the upper electrode 130 (see FIGS. 1 and 2), and as shown in FIG. 3(c), a metal plate 150 is bonded to the upper electrode 130. During bonding, the metal plate 150 is pressed toward the upper electrode 130. This pressing is performed so that the metal plate 150 is electrically connected to the upper electrode 130. If the pressing is performed appropriately, an electrical connection can be established between the upper electrode 130 and the metal plate 150 even if the insulating adhesive 132 is present between the upper electrode 130 and the metal plate 150. Furthermore, within a predetermined limit, the adhesive strength after bonding can be increased by thinning the insulating adhesive 132 between the metal plate 150 and the upper electrode 130.

[0037] Next, the piezoelectric plate 100 is cut from the lower surface 104 side of the piezoelectric plate 100, so that the slits 106 reach from the upper surface 102 to the lower surface 104 (full cut), as shown in FIG. 4(a). This process can be performed with the piezoelectric plate 100 turned upside down. In this way, the lower electrode layer is divided into multiple parts to become lower electrodes 170. The piezoelectric plate 100 is divided into multiple parts, and the partial piezoelectric portions 112 become piezoelectric portions 110. A lower electrode 170 is formed at the lower end of each of the piezoelectric portions 110.

[0038] Next, an additional insulating adhesive 172 (see FIG. 7) is applied to the lower surface of the lower electrode 170, and an additional metal plate 190 is adhered to the lower electrode 170, as shown in FIG. 4(b). As in the case of the metal plate 150, the additional metal plate 190 is pressed against the lower electrode 170, and the additional metal plate 190 and the lower electrode 170 are electrically connected to each other.

[0039] In this manner, the piezoelectric vibrator 10 is manufactured. However, in the present invention, the manufacturing direction of the piezoelectric vibrator 10 is not limited to the above method. For example, the piezoelectric plate 100 may be cut only from the upper surface 102 side (or the lower surface 104 side).

[0040] 5 and 6, a method for manufacturing the piezoelectric vibrator 10 in which cutting is performed only from the top surface 102 of the piezoelectric plate 100 will be described.

[0041] First, as shown in Fig. 5(a), a piezoelectric plate 100 is prepared. Then, silver paste (not shown) is applied to each of the upper surface 102 and the lower surface 104 of the piezoelectric plate 100, and heated and sintered to form an upper electrode layer that will become the upper electrode (baked silver electrode) 130 (see Figs. 1 and 2) and a lower electrode layer that will become the lower electrode (baked silver electrode) 170 (see Figs. 1 and 2).

[0042] Next, as shown in FIG. 5( b ), a reinforcing plate 200 is attached to the surface of the lower electrode layer formed on the lower surface 104 of the piezoelectric plate 100 .

[0043] Next, as shown in FIG. 5(c), the piezoelectric plate 100 is cut from the upper surface 102 side to form slits 106. This cutting is performed so that the slits 106 reach the lower surface 104. The slits 106 are formed in a lattice pattern in plan view (see FIG. 2). As a result, the upper electrode layer formed on the upper surface 102 of the piezoelectric plate 100 is divided into multiple pieces to become upper electrodes 130. The piezoelectric plate 100 is also divided into multiple piezoelectric portions 110. At this time, the piezoelectric portions 110 are held together by the reinforcing plate 200.

[0044] Next, an insulating adhesive 132 (see FIG. 7) is applied to the upper surface of the upper electrode 130, and a metal plate 150 is adhered to the upper electrode 130 as shown in FIG. 6(a).

[0045] 6(b), the reinforcing plate 200 is removed from the piezoelectric body part 110. At this time, the piezoelectric body part 110 is supported by the metal plate 150, and is held integrally by the metal plate 150 even after the reinforcing plate 200 is removed.

[0046] Next, an additional insulating adhesive (see FIG. 7) is applied to the lower surface of the lower electrode 170, and an additional metal plate 190 is adhered to the lower electrode 170 as shown in FIG. 6(c).

[0047] The piezoelectric vibrator 10 can also be manufactured in the above manner.

[0048] As described above, in the manufacturing process of the piezoelectric vibrator 10, the metal plate 150 is pressed toward the upper electrode 130. At this time, the insulating adhesive 132 is extruded into the slits 106, as can be seen from FIG. 7 . The insulating adhesive 132 extruded into the slits 106 may affect the vibration characteristics of the piezoelectric body portion 110. The same applies to the additional insulating adhesive 172. According to experiments conducted by the applicant, it has been found that the vibration characteristics of the piezoelectric body portion 110 are affected when 30% of the slits 106 are filled with the insulating adhesive 132 or the additional insulating adhesive 172 in the vertical direction. In other words, to achieve the desired vibration of the piezoelectric vibrator 10, the insulating adhesive 132 or the additional insulating adhesive 172 filling the slits 106 needs to be 30% or less of the size of the slits 106 in the vertical direction. In this embodiment, the insulating adhesive 132 or the additional insulating adhesive 172 is extruded into the slits 106 on both the metal plate 150 side and the additional metal plate 190 side. Therefore, it is preferable that the insulating adhesive 132 extruded into the slit 106 is present only in an area above the slit 106 that is 15% or less of the size H of the slit 106 in the vertical direction. Similarly, it is preferable that the additional insulating adhesive 172 is present only in an area below the slit 106 that is 15% or less of the size H of the slit 106 in the vertical direction. In other words, it is preferable that the size Du of the insulating adhesive 132 that has entered the slit 106 satisfies Du≦0.15H. It is also preferable that the size Dl of the additional insulating adhesive 172 that has entered the slit 106 satisfies Dl≦0.15H. This allows the piezoelectric vibrator 10 to achieve the desired vibration.

[0049] (Second embodiment) A piezoelectric vibrator 10A according to a second embodiment of the present invention will be described with reference to Figures 8 and 9. Here, among the components of piezoelectric vibrator 10A, the same components as those of piezoelectric vibrator 10 according to the first embodiment are given the same reference numerals, and their description will be omitted.

[0050] 8, a piezoelectric vibrator 10A according to the second embodiment of the present invention includes a plurality of piezoelectric body portions 110A, a plurality of upper electrodes 130, a metal plate 150, a piezoelectric base portion 108, and a lower electrode 170A. The piezoelectric vibrator 10A also includes an insulating adhesive 132 (not shown).

[0051] As can be seen from Figures 8 and 9, the piezoelectric body portion 110A is formed similarly to the piezoelectric body portion 110, and is arranged in a first horizontal direction and a second horizontal direction rearward. The piezoelectric base portion 108 is formed integrally with the piezoelectric body portion 110A, and connects the lower ends of the piezoelectric body portions 110A. The lower electrode 170A is formed on the lower surface of the piezoelectric base portion 108. The piezoelectric vibrator 10A does not have an additional metal plate 190 (see Figure 1), and the lower electrode 170A is used as a lower common electrode.

[0052] In this embodiment, the piezoelectric body portion 110A is formed integrally with the piezoelectric base portion 108, and is supported by being adhered to a metal plate 150 having a predetermined rigidity via the upper electrode 130 using an insulating adhesive 132. This allows the piezoelectric vibrator 10 to achieve a stable structure. Furthermore, by limiting the amount of insulating adhesive 132 extruded into the slit 106 to a predetermined area or less, desired vibration can be obtained.

[0053] Next, a method for manufacturing the piezoelectric vibrator 10A will be described.

[0054] The piezoelectric vibrator 10A can be manufactured by carrying out the same steps as those shown in Figures 3(a), (b), and (c). The thickness of the piezoelectric substrate 100 used is equal to the sum of the size of the piezoelectric portion 110A in the vertical direction and the size of the piezoelectric base portion 108. The cutting to form the slits 106 in the piezoelectric plate 100 is carried out so that the size of the slits 106 in the vertical direction is equal to the size of the piezoelectric portion 110A. The size of the piezoelectric base portion 108 in the vertical direction is set to be large enough to hold the piezoelectric portion 110A together after the slits 106 are formed.

[0055] In the piezoelectric vibrator 10A according to this embodiment, the lower end of the piezoelectric body portion 110A is connected by the piezoelectric base portion 108. Therefore, the vibration characteristics of the piezoelectric vibrator 10A may be inferior to the vibration characteristics of the piezoelectric vibrator 10. However, the manufacturing process of the piezoelectric vibrator 10A is simpler than the manufacturing process of the piezoelectric vibrator 10. Therefore, the manufacturing cost of the piezoelectric vibrator 10A is lower than that of the piezoelectric vibrator 10, and the piezoelectric vibrator 10A is inexpensive.

[0056] Although the present invention has been described above using several embodiments, the present invention is not limited to the above embodiments, and various modifications and variations are possible without departing from the spirit of the present invention. For example, in the above embodiments, the piezoelectric plate 100 is rectangular when viewed from the top to bottom, but a piezoelectric substrate 100 having a shape other than a rectangle, such as a circle, may also be used. Furthermore, in the above embodiments, the insulating adhesive 132 and the additional insulating adhesive 152 are applied to the upper electrode 130 or the lower electrode 170, but they may also be applied to the metal plate 150 and the additional metal plate 190. [Explanation of symbols]

[0057] 10, 10A piezoelectric vibrator 100 Piezoelectric plate 102 Top surface 104 Bottom surface 106 Slit 108 Piezoelectric base 110, 110A Piezoelectric part 112 partial piezoelectric body 130 Upper electrode 132 Insulating adhesive 150 metal plate 170, 170A lower electrode 172 Additional insulating adhesives 190 Additional metal plates 200 Reinforcement plate

Claims

1. A piezoelectric vibrator including a plurality of piezoelectric portions, a plurality of upper electrodes, a metal plate, and an insulating adhesive, Each of the piezoelectric portions extends in the vertical direction, A slit is formed between the piezoelectric portions, The upper electrodes are formed on the upper ends of the piezoelectric portions, all of the upper electrodes are bonded to the metal plate by the insulating adhesive; the metal plate is electrically connected to all of the upper electrodes and supports the piezoelectric body portion via the insulating adhesive and the upper electrodes; The insulating adhesive is present only in an area above the slit, the area being 15% or less of the size of the slit in the vertical direction. Piezoelectric vibrator.

2. 2. The piezoelectric vibrator according to claim 1, Each of the piezoelectric body portions is a columnar body having a longitudinal direction in the up-down direction, The piezoelectric body portions are aligned in a first horizontal direction and a second horizontal direction that are perpendicular to the up-down direction and perpendicular to each other, The slits are formed in a grid pattern. Piezoelectric vibrator.

3. 2. The piezoelectric vibrator according to claim 1, the piezoelectric vibrator further comprises a plurality of lower electrodes, an additional metal plate, and an additional insulating adhesive; Each of the piezoelectric body portions is separated from the adjacent piezoelectric body portion, The lower electrodes are formed on the lower ends of the piezoelectric bodies, all of the lower electrodes are bonded to the additional metal plate by the additional insulating adhesive; the additional metal plate is electrically connected to all of the lower electrodes and supports the piezoelectric body portion via the additional insulating adhesive and the lower electrodes; The additional insulating adhesive is present only in a region below the slit, the region being 15% or less of the size of the slit in the vertical direction. Piezoelectric vibrator.

4. 2. The piezoelectric vibrator according to claim 1, The piezoelectric vibrator further includes a piezoelectric base and a lower electrode, the piezoelectric base is integrally formed with the piezoelectric body portion and connects lower ends of the piezoelectric body portions, The lower electrode is formed on the lower surface of the piezoelectric base. Piezoelectric vibrator.

5. 2. The piezoelectric vibrator according to claim 1, The metal plate is made of a material having a Young's modulus of 50 GPa or more. Piezoelectric vibrator.

6. 6. The piezoelectric vibrator according to claim 5, The metal plate has an area of ​​S [mm ２ ], and the plate thickness is T [mm], then Formula 1 is satisfied. Piezoelectric vibrator. [Equation 1]

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