JP2010199271A - Multilayer piezoelectric element, manufacturing method thereof, and vibrator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer piezoelectric element for preventing an outer electrode and a supporting plate from coming into contact with each other and improving reliability in insulation, and a manufacturing method thereof and a vibrator. <P>SOLUTION: The element body 20 includes a laminated body 13 constituted by laminating piezoelectric layers 7 and inner electrode layers 9 alternately and having a pair of rectangular main surfaces, and a pair of side surfaces provided on both longitudinal ends of main surfaces, and a pair of outer electrodes 17, 19 electrically connected to inner electrode layers 9 provided on a pair of side surfaces of the laminated layer 13 respectively, wherein the element body a inclined surface 20a is formed by obliquely cutting and removing a corner part c formed with a one main surface and a side surface of the laminated layer 13, together with outer electrodes 17, 19 formed on the side surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a multilayer piezoelectric element, a manufacturing method thereof, and a vibrating body, and more particularly, to a bimorph type or unimorph type multilayer piezoelectric element used in a flat speaker device for a computer, a mobile phone or a small terminal device, a manufacturing method thereof, and a vibrating body It is about.

  A conventional multilayer piezoelectric element is formed by alternately laminating piezoelectric layers and internal electrode layers, and a pair of rectangular main surfaces formed in the laminating direction of the piezoelectric layers and internal electrode layers alternate in the longitudinal direction. A plate-like laminate having a pair of side surfaces drawn to the outside, and external electrodes provided at both ends in the longitudinal direction of the laminate.

  As shown in FIG. 7, the conventional vibrating body has a bimorph type (FIG. 7A) and a main surface of the multilayer piezoelectric element as described above bonded to a support plate using an adhesive. A unimorph type (FIG. 7B) vibrator was produced (see, for example, Patent Document 1).

  As shown in FIG. 7A, the conventional vibrating body is configured by bonding laminated piezoelectric elements 30 and 36 to the upper and lower surfaces of a support plate 34 with a bottom surface side adhesive layer 35.

  That is, the multilayer piezoelectric elements 30 and 36 are composed of a laminate formed by alternately laminating seven layers of piezoelectric bodies 31 and six layers of internal electrode layers 32, and surfaces formed on the upper and lower main surfaces of the laminate. An electrode layer 33a and a pair of external electrodes 33b provided at both ends in the longitudinal direction of the laminate are provided. The laminated body is plate-shaped, and the upper and lower main surfaces are rectangular, and in the longitudinal direction of the laminated body, the laminated body has a pair of side surfaces from which the internal electrode layers 32 are alternately drawn. An external electrode 33b is provided. The external electrode 33b protrudes closer to the support plate 34 than the main surface on the support plate side of the laminate.

  The six internal electrode layers 32 and the two surface electrode layers 33a are alternately formed as electrode layers. The pair of external electrodes 33b includes three layers of internal electrode layers 32 and one layer on the side surface of the laminate. The surface electrode layer 33a is electrically connected.

  Usually, an adhesive is applied to the support plate 34, and the laminated piezoelectric elements 30 and 36 are pressed against the adhesive layer 35 to be bonded. As shown in FIG. The adhesive layer 35 is applied in a thicker area than the area of the main surface of the multilayer piezoelectric elements 30 and 36, and the multilayer piezoelectric elements 30 and 36 are pressed before the adhesive layer 35 is dried. It was dried and joined.

JP 2007-329431 A

  However, in the conventional vibrating body, the external electrode 33b protrudes to the support plate 34 side from the main surface of the laminate, so that the external electrode 33b and the support plate 34 come into contact with each other unless the amount of the adhesive layer 35 applied is sufficient. As a result, there is a problem that insulation cannot be secured.

  In addition, a surface electrode layer 33a is formed on the main surface of the multilayer body on the support plate 34 side so as to effectively vibrate the multilayer piezoelectric elements 30 and 36. The surface electrode layer 33a and the support plate 34 In order to prevent electrical conduction, the thickness h of the adhesive layer 35 must be increased.

  An object of the present invention is to provide a laminated piezoelectric element that can prevent contact between an external electrode and a support plate and improve insulation reliability, a manufacturing method thereof, a vibrating body, and a manufacturing method thereof.

  The multilayer piezoelectric element of the present invention is formed by alternately laminating piezoelectric layers and internal electrode layers, and includes a pair of rectangular main surfaces and a pair of side surfaces provided on both ends in the longitudinal direction of the main surfaces. And a pair of external electrodes provided on the pair of side surfaces of the laminate and electrically connected to the internal electrode layer. A corner portion formed by one of the main surface and the side surface is obliquely cut and removed together with the external electrode formed on the side surface to form an inclined surface.

  In the multilayer piezoelectric element of the present invention, since the external electrode does not protrude from one main surface of the multilayer body, for example, a vibrating body bonded to a support plate via an adhesive layer is used by using this multilayer piezoelectric element. When manufacturing, it is possible to prevent contact between the external electrode and the support plate, and it is possible to prevent conduction between the external electrode and a wiring conductor formed on the support plate or the support plate made of a conductor that should not be electrically connected to the external electrode. In addition, the insulation reliability of the vibrator can be improved.

  Also, the method for producing a laminated piezoelectric element according to the present invention is formed by alternately laminating piezoelectric layers and internal electrode layers, and is provided on a pair of rectangular main surfaces and both longitudinal ends of the main surfaces. Producing a device body comprising a plate-like laminate having a pair of side surfaces and a pair of external electrodes electrically connected to the internal electrode layer on the pair of side surfaces of the laminate, A step of forming an inclined surface in the element body by obliquely cutting and removing a corner formed by one of the main surface and the side surface of the laminate together with the external electrode formed on the side surface. It is characterized by that.

  In general, when the thickness of the laminate is thin, it is difficult to form the external electrode only on the side surface of the laminate so that the external electrode does not protrude from one main surface of the laminate. Even if the thickness of the laminate is thin, for example, after forming external electrodes on both ends in the longitudinal direction of the laminate so as to protrude from one main surface of the laminate by a dip coating method, for example, In order to form an inclined surface by obliquely cutting and removing the corner formed by one main surface and the side surface of the body together with the external electrode formed on the side surface, the external electrode protrudes from one main surface of the laminate. It is possible to easily produce a laminated piezoelectric element that is not present. As a result, for example, it is possible to easily manufacture a vibrating body in which a laminated piezoelectric element is bonded to a support plate, and it is possible to prevent contact between the external electrode and the support plate. It is possible to reliably insulate a support plate made of a conductor that should not be conducted or a wiring conductor formed on the support plate.

  Further, in the method of manufacturing the multilayer piezoelectric element of the present invention, in the step of manufacturing the element body, a surface electrode layer electrically connected to one of the pair of external electrodes is formed on the other main surface of the multilayer body. It is characterized by doing.

  The vibrating body according to the present invention is characterized in that one main surface of the multilayer body of the multilayer piezoelectric element according to claim 1 is bonded to a support plate by an adhesive layer. In such a vibrating body, it is possible to prevent conduction between the external electrode and a support plate made of a conductor that should not be electrically connected to the external electrode or a wiring conductor formed on the support plate, thereby improving the insulation reliability of the vibrating body. it can.

  In the multilayer piezoelectric element of the present invention, the external electrode does not protrude from one main surface of the multilayer body. Therefore, when a vibrating body in which the multilayer piezoelectric element is bonded to the support plate via the adhesive layer is produced, It is possible to prevent conduction between the electrode and a support plate made of a conductor that should not be electrically connected to the external electrode or a wiring conductor formed on the support plate, thereby improving the insulation reliability of the vibrator.

  In the manufacturing method of the multilayer piezoelectric element of the present invention, for example, after forming external electrodes by dip coating on both ends in the longitudinal direction of the multilayer body, corners formed by one main surface and side surfaces of the multilayer body Since the inclined surface is formed by obliquely cutting and removing together with the external electrode formed on the side surface, a multilayer piezoelectric element in which the external electrode does not protrude from one main surface of the multilayer body can be easily produced. Since the main surface of the laminated body on the side where the inclined surface of the multilayer piezoelectric element is formed is bonded to the support plate via the adhesive layer, the external electrode does not protrude on the support plate side, and the external electrode Between the external electrode and the support plate made of a conductor that should not be electrically connected to the external electrode or the wiring conductor formed on the support plate can be reliably insulated.

(A) is sectional drawing of the bimorph type vibrating body of this invention, (b) is a partially expanded sectional view of (a). It is a top view of FIG. It is sectional drawing which shows the state which bonded the lamination type piezoelectric element to the support plate with the adhesive layer on the bottom face side, and the adhesive layer on the side face side. The bimorph type | mold vibrating body of this invention which has a conductor layer is shown, (a) is sectional drawing, (b) is a top view. It is process drawing for demonstrating the manufacturing method of the lamination type piezoelectric element of this invention. (A) is sectional drawing of the vibrating body using the lamination type piezoelectric element by which the longitudinal direction side surface of a laminated body is a burnt surface, (b) is a cross section which expands and shows a part of (a) FIG. 1 shows a conventional bimorph type vibrator, (a) is a cross-sectional view, (b) is a cross-sectional view when an adhesive layer is widely formed, and a laminated piezoelectric element is pressed against and bonded to the adhesive layer. It is.

(First form)
Hereinafter, an embodiment of a vibrating body using the multilayer piezoelectric element of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a bimorph type vibrator of the present invention, and FIG. 2 is a plan view.

  As shown in FIGS. 1 and 2, the bimorph type vibrating body of the present invention is configured by bonding laminated piezoelectric elements 1 and 3 to the upper and lower surfaces of a support plate 5 with an adhesive layer 6. The present invention is not limited to the bimorph type vibrator, and the effect of the present invention can be obtained even with a unimorph type vibrator in which a laminated piezoelectric element is joined to one side of the support plate 5.

  The laminated piezoelectric elements 1 and 3 are formed by alternately laminating 6 layers of piezoelectric layers 7 made of ceramics and 6 layers of internal electrode layers 9, and a piezoelectric body that does not contribute to vibration on the outermost side on the support plate 5 side. The laminated body 13 having the layer 7, the surface electrode layer 15 formed on the opposite side of the laminated body 13 from the support plate 5, and a pair of external electrodes 17 provided at both ends in the longitudinal direction x of the laminated body 13. , 19.

  In FIG. 1, the thickness of the laminated piezoelectric elements 1 and 3 is enlarged for easy understanding.

  The outermost piezoelectric layer 7 on the support plate 5 side can be said to be a piezoelectric layer 7 in which the surface electrode layer is not formed on the support plate 5 side, and in other words, an inactive layer ( Hereinafter, the outermost piezoelectric layer 7 on the support plate 5 side of the laminate 13 may be referred to as an inactive layer 11).

  The laminated body 15 is plate-shaped, the upper and lower main surfaces are rectangular, and the longitudinal direction x of the main surface of the laminated body 15 has a pair of side surfaces from which the internal electrode layers 9 are alternately drawn. .

  Referring to the multilayer piezoelectric element 1 of FIG. 1, the upper main surface of the multilayer body 15 is composed of the upper surface of the piezoelectric layer 7, and the lower main surface of the multilayer body 13 is a piezoelectric element on which no surface electrode layer is formed. A surface electrode layer 15 is formed on the upper main surface of the laminate 15, which is composed of the lower surface of the body layer 7 (inert layer 11).

  The layer structure of the multilayer piezoelectric elements 1 and 3 will be described in detail with reference to the multilayer piezoelectric element 1 of FIG. 1. An inactive layer 11 and an internal electrode layer formed on the upper surface of the lowermost inactive layer 11. 9, the piezoelectric layer 7 formed on the internal electrode layer 9, the internal electrode layer 9 and the piezoelectric layer 7 that are alternately stacked on the upper surface of the piezoelectric layer 7, and the stacked body 13. And a surface electrode layer 15 formed on the uppermost piezoelectric layer 7.

  One inactive layer 11, six piezoelectric layers 7, and six internal electrode layers 9 are laminated and fired at the same time. As will be described later, the surface electrode layer 15 is formed by applying a paste and baking it after producing the laminate 13.

  Although the thickness of the inactive layer 11 can be set arbitrarily, although the insulating property can be improved when the thickness of the inactive layer 11 is increased, vibration suppression by the inactive layer 11 is increased, so that good vibration can be obtained. The thinner one is desirable.

  In addition, the inactive layer 11 is preferably made of the same material and the same thickness as the piezoelectric layer 7 which becomes an active layer sandwiched between electrode layers from the viewpoint of easy manufacture. This is because the same green sheet as that of the piezoelectric layer 7 can be used to produce the laminated molded body.

  The rectangular main surface of the laminated body 13 desirably has a width of 5 mm or less and a length of 10 mm or more. In such a laminated piezoelectric element, the displacement in the longitudinal direction x of the main surface is particularly large, and the amount of displacement transmitted to the support plate 5 is large, so that the adhesive layer 6 on the bottom side is used as described later. It can be suitably used for suppressing displacement absorption. The rectangular main surface of the laminate 13 can be suitably used particularly when the width is 5 mm or less and the length is 17 mm or more.

  As the piezoelectric layer 7, conventionally used piezoelectric ceramics such as PZ, PZT, Bi layered compounds, lead-free piezoelectric materials such as tungsten bronze structure compounds, and the like can be used. The thickness of the piezoelectric layer 7 is set to 10 to 100 μm from the viewpoint of low voltage driving.

  The internal electrode layer 9 preferably contains a metal component composed of silver and palladium and a material component constituting the piezoelectric layer 7. By including the material component constituting the piezoelectric layer 7 in the internal electrode layer 9, it is possible to reduce the stress due to the difference in thermal expansion between the piezoelectric layer 7 and the internal electrode layer 9, and to provide a stacked piezoelectric element without stacking faults. Elements 1 and 3 can be obtained. The internal electrode layer 9 is not particularly limited to a metal component composed of silver and palladium, and is not limited to a material component constituting the piezoelectric layer 7 as a ceramic component. It may be.

  The surface electrode layer 15 and the external electrodes 17 and 19 preferably contain a glass component in the metal component made of silver. By containing the glass component, it is possible to obtain a strong adhesion between the piezoelectric layer 7 and the internal electrode layer 9 and the surface electrode layer 15 or the external electrodes 17 and 19.

  In the multilayer piezoelectric element of the present invention, a corner portion formed by one main surface and side surfaces of the multilayer body 13 is formed on the element body 20 formed by forming the external electrodes 17 and 19 on both side surfaces of the multilayer body 13. And the external electrodes 17 and 19 formed on the side surfaces are cut and removed obliquely to form an inclined surface 20a. Therefore, the lower surfaces of the external electrodes 17 and 19 are cut and removed at the same angle as the inclined surface 20 a of the multilayer body 13.

  The external electrodes 17, 19 are formed on the side surfaces of the multilayer body 13, and the upper ends of the external electrodes 17, 19 are both ends in the longitudinal direction x of the main surface of the multilayer body 13 opposite to the support plate 5 from the side surfaces of the multilayer body 13. The external electrodes 17 and 19 are extended to the portion, and the external electrode 19 is connected to the surface electrode layer 15 at one end portion in the longitudinal direction x of the main surface of the laminate 13 opposite to the support plate 5, At the other end, the external electrode 17 is bonded onto the piezoelectric layer 7.

  The external electrodes 17 and 19 are mainly formed on the side surface in the longitudinal direction x of the main surface of the multilayer body 13, and are not formed on the main surface of the multilayer body 13 on the support plate 5 side. In the present invention, the external electrodes 17 and 19 may be any one that does not protrude from the main surface of the laminate 13 on the support plate 5 side, and the width of the main surface of the laminate 13 in the longitudinal direction x and the width of the main surface. It may be formed on the side surface in the direction.

  Referring to the multilayer piezoelectric element 1 in FIG. 1, the multilayer piezoelectric element 1 has six internal electrode layers 9 and one surface electrode layer 15 alternately formed as electrode layers, and one (left side) external electrode. The electrode 17 is electrically connected to the three internal electrode layers 9 on the left side surface of the multilayer body 13, and the other (right side) external electrode 19 is connected to the inner side of the three layers on the right side surface of the multilayer body 13. The electrode layer 9 and the surface electrode layer 15 are electrically connected.

  The support plate 5 side of the external electrodes 17, 19 is not formed on the main surface of the inert layer 11 on the support plate 5 side, and from the main surface of the inert layer 11 on the support plate 5 side to the support plate 5 side. There is no protrusion.

In the vibrating body, the main surface of the laminated body 13 on the support plate 5 side and the support plate 5 are joined by an adhesive layer 6. The thickness h ₁ of the adhesive layer 6 between the multilayer piezoelectric element 1, 3 and the support plate 5 is a 20μm or less. In particular, it is desirable thickness h ₁ of the adhesive layer 6 of the bottom side is 10μm or less. Thus, when the thickness h ₁ of the adhesive layer 6 of the bottom side is 20μm or less, it becomes easier to convey the vibrations of the laminate 13 to the support plate 5 can be suitably used. On the other hand, even if the thickness of the adhesive layer 6 on the bottom surface side is reduced, the inert layer 11 is the outermost layer of the laminate 13, and a surface electrode layer is formed on the main surface of the laminate 13 on the support plate 5 side. In addition, since the external electrodes 17 and 19 do not protrude from the surface of the inactive layer 11 on the support plate side, insulation between the multilayer piezoelectric elements 1 and 3 and the support plate 5 can be secured.

  Further, when the number of stacked piezoelectric layers 7 of the multilayer body 13 is 30 or less, the displacement of the multilayer piezoelectric element is small, and therefore it is necessary to efficiently transmit the displacement of the multilayer piezoelectric element to the support plate. Therefore, it can be used more suitably.

  The thickness of the laminated body 13 is desirably 700 μm or less. Thereby, when used as a bimorph or a unimorph, a large vibration can be obtained.

  As an adhesive for forming the adhesive layer 6 on the bottom surface side, known ones such as an epoxy resin, a silicon resin, and a polyester resin can be used. As a method for curing the resin used for the adhesive, the vibrating body can be produced by using any of thermosetting, photocuring, anaerobic curing, and the like.

  As shown in FIG. 3, the laminated piezoelectric elements 1 and 3 are joined to the support plate 5 not only by the adhesive layer 6 on the bottom side but also by the adhesive layer 21 on the side surface. The peeling of the multilayer piezoelectric elements 1 and 3 from the support plate 5 due to impact can be suppressed.

  In the vibrating body of the present invention, the external electrode 19 is electrically connected to the electrode pattern formed on the insulating support plate 5 or the conductive support plate 5 itself, and a voltage is applied between the external electrodes 17 and 19 to laminate the external electrode 19. The piezoelectric elements 1 and 3 are driven. A voltage is applied so that one of the multilayer piezoelectric element 1 and the multilayer piezoelectric element 3 is contracted and the other is extended. Thereby, the bimorph type vibrator as shown in FIGS. 1 and 3 vibrates greatly.

  FIG. 4 shows a vibrating body in which the support plate 5 is made of a metal or an alloy, and a conductor layer 25 is formed to electrically connect one external electrode 17 and the support plate 5.

  Next, the manufacturing method of the vibrating body of this invention is demonstrated based on FIG. First, a binder, a dispersant, a plasticizer, and a solvent are kneaded with the piezoelectric material powder to prepare a slurry. As the piezoelectric material, any of lead-based and non-lead-based materials can be used.

  Next, the obtained slurry can be formed into a sheet shape to obtain a green sheet, and an internal electrode pattern is formed by printing an internal electrode paste on the green sheet, and a green sheet on which this electrode pattern is formed is desired Are laminated, and only the green sheet is laminated on the uppermost layer to produce a laminated molded body.

  Next, the laminate 13 can be obtained by degreasing, firing, and cutting the laminate compact to a predetermined size. The laminated body 13 processes the outer peripheral portion as necessary, prints the paste of the surface electrode layer 15 on one principal surface in the lamination direction of the piezoelectric layer 7 of the laminated body 13, and then continues to the longitudinal direction x of the laminated body 13 The element body 20 can be obtained by printing pastes of the external electrodes 17 and 19 on both side surfaces of the substrate and baking the electrodes at a predetermined temperature.

  As shown in FIG. 5 (a), when the external electrodes 17 and 19 are formed by a paste coating method when the thickness of the laminated body is thin, particularly 700 μm or less, A small amount is formed not only on both side surfaces in the longitudinal direction x of the body 13 but also on both main surfaces. When bonded to the support plate in this state, as shown in FIG. 7, the external electrode protrudes to the support plate side from the main surface of the laminate, and the external electrode and the support are supported when the adhesive layer is not applied sufficiently. The plates come into contact with each other, resulting in a decrease in insulation.

  Therefore, as shown by a broken line in FIG. 5A, the corner portion c formed by one main surface and the side surface of the laminate 13 of the element body 20 is slanted together with the external electrodes 17 and 19 formed on the side surface. Then, as shown in FIGS. 5B and 5C, an inclined surface 20a is formed on the element body 20.

  The cutting and removing can be performed by, for example, dicing or generally used polishing.

  The range to be cut and removed is a range in which the connection with the internal electrode layer 9 connected to the external electrodes 17 and 19 is not broken. Specifically, the range is less than the thickness of the inactive layer 11. When there are two or more inactive layers, they can be cut and removed with less than the total thickness.

  After forming the external electrodes 17 and 19 on both ends of the multilayer body 13 in this way, the end portions of the external electrodes 17 and 19 together with the corners c of the multilayer body 13 are cut and removed. When forming 19, it is not necessary to control so as to be formed only on the side surface of the laminated body 13, and the external electrode is formed together with the corner portion c of the laminated body 13 by a simple manufacturing method such as a dip coating method. By cutting and removing 17 and 19, the external electrodes 17 and 19 can be prevented from protruding from the main surface of the laminated body 13 on the support plate 5 side.

  Next, in order to impart piezoelectricity to the multilayer piezoelectric elements 1 and 3, a DC voltage is applied through the surface electrode layer 15 or the external electrodes 17 and 19 to polarize the multilayer piezoelectric elements 1 and 3.

  Next, an adhesive is applied to the support plate 5, the inclined surface 20 a side of the multilayer piezoelectric elements 1, 3 is pressed onto the support plate 5, and then the adhesive is irradiated with heat or ultraviolet rays. It can be cured to obtain the vibrating body of the present invention.

  In the vibrating body of the present invention, it is not necessary to consider the contact between the external electrodes 17 and 19 and the support plate 5 and the conduction between the support plate 5 and the inert layer 11. The thickness of the adhesive layer 6 can be reduced, the displacement absorption by the adhesive layer 6 is reduced, and the displacement by the laminated piezoelectric elements 1 and 3 can be effectively applied to the support plate 5. The amount of displacement can be improved.

Further, since the external electrodes 17 and 19 are not formed on the main surface of the laminated body 13 on the support plate 5 side, the laminated piezoelectric elements 1 and 3 are attached to the support plate 5 by the adhesive layer 6 as in the prior art. When joining, it is possible to prevent contact between the external electrodes 17 and 19 and the support plate 5, improve insulation reliability between the external electrodes 17 and 19 and the support plate 5, and force the multilayer piezoelectric elements 1 and 3 to be impossible. Force does not act, and the generation of cracks can be suppressed.
(Second form)
As shown in FIG. 1, the longer the length of the main surface of the multilayer body 13, in other words, the longer the length of the multilayer body 13, the longer the length of the main surface of the internal electrode layer 9 during firing. Since the amount of shrinkage in the direction x increases and the amount of dent at the tip of the internal electrode layer 9 increases from the side surface of the multilayer body 13, the inner electrode layer 9 is usually cut to the side surface of the multilayer body 13 after firing. It is exposed and external electrodes 17 and 19 are formed on the side surfaces to improve connection reliability. However, in the present invention, from the side of the laminate 13 of the external electrodes 17 and 19 without being cut after firing. In order to improve the bonding strength, it is desirable that the side surface of the laminate 13 be a burnt skin surface.

  This form will be described. In the vibrating body of this form, as shown in FIG. 6, the main surface on the support plate 5 side of the laminate 13 and the support plate 5 are joined by the adhesive layer 6 on the bottom surface side, and the external electrodes 17 and 19 are exposed. A part of the surface, the inclined surface 20 a and the support plate 5 are joined by the adhesive layer 21 on the side surface side. In other words, the adhesive layer 21 on the side surface side adheres to a part of the exposed surface of the external electrodes 17 and 19 and the inclined surface 20a, and also adheres to the surface of the support plate 5 so that the bottom is widened.

  The adhesive layer 21 on the side surface side is continuous with the adhesive layer 6 on the bottom surface side. In the present invention, the adhesive layer between the support plate 5 and the portion other than the inclined surface 20a of the inert layer 11 is the bottom surface. The adhesive layer 6 on the side was defined as the adhesive layer 21 on the side, and the adhesive layer positioned on the outer side was defined as the adhesive layer 21 on the side.

  And in this form, a pair of side surface of the laminated body 13 is made into a baking surface. Accordingly, the side surface in the longitudinal direction x of the main surface of the multilayer body 13 reflects the shape of the ceramic particles constituting the piezoelectric layer 7, and as shown in FIG. 6B, the unevenness is formed by the ceramic particles. Further, due to the firing shrinkage of the internal electrode layer 9, an opening is formed on the side surface of the multilayer body 13, and irregularities due to ceramic particles are formed. In addition, by applying the electrode paste of the external electrodes 17 and 19 to the side surface of the internal electrode layer 9 that has openings due to firing shrinkage to form the external electrodes 17 and 19, the external electrode material bites into the irregularities due to the ceramic particles. In addition, the external electrode material enters the opening, and is seized in this state, so that the bonding strength of the external electrodes 17 and 19 to the side surface of the laminate 13 can be improved.

  In particular, the support plate 5 side of the external electrodes 17 and 19 is not formed on the main surface of the laminate 13 on the support plate 5 side, and the bonding strength of the external electrodes 17 and 19 to the laminate 13 is likely to decrease. Therefore, this form can be used suitably. Further, since the processing such as flattening the side surface of the laminated body 13 is not performed after sintering, the processing cost can be reduced and the production cost can be reduced.

  Here, the burned surface means having a porcelain surface as it is after sintering without performing any processing such as flattening the side surface of the laminate 13 such as dicing or barrel after sintering.

  Next, a method for manufacturing the vibrating body will be described. A laminated molded body is produced as in the first embodiment. This laminated molded body is cut into a desired shape to produce a piece-shaped laminated molded body for an element. When cutting, the internal electrode pattern is cut so as to be alternately exposed on the side surface of the element laminated molded body.

  Next, the laminated body 13 can be obtained by degreasing and firing the laminated molded body for an element. After firing, the side surface on which the external electrodes 17 and 19 of the multilayer body 13 are formed is not processed at all, and therefore the side surface of the piezoelectric layer 7 is uneven by the ceramic particles constituting the piezoelectric layer 7. Further, since the internal electrode layer 9 has a larger sintering shrinkage than the piezoelectric layer 7, the tip of the internal electrode layer 9 that should be connected to the external electrodes 17 and 19 is slightly recessed from the side surface of the laminate 13. In other words, an opening due to contraction of the internal electrode layer 9 is formed on the side surface of the multilayer body 13.

  Thereafter, the paste of the surface electrode layer 15 is printed on both main surfaces in the stacking direction of the piezoelectric layer 7 of the stacked body 13, and subsequently, the paste of the external electrodes 17 and 19 is applied to both side surfaces in the longitudinal direction x of the stacked body 13. The stacked piezoelectric elements 1 and 3 shown in FIG. 6 can be obtained by printing, baking the electrodes at a predetermined temperature, and cutting and removing the corners c of the element body 2. By printing and baking the paste of the external electrodes 17 and 19, the paste of the external electrodes 17 and 19 enters the opening formed on the side surface of the laminated body 13, and the external electrodes 17 and 19 enter the internal electrode layer 9. Will be connected. When the length of the laminate 13 is long, the amount of firing shrinkage of the internal electrode layer 9 is large, and the opening is long, vacuuming is performed to make it easier to put the paste of the external electrodes 17 and 19 into the opening. The internal electrode layer 9 and the external electrodes 17 and 19 can be reliably connected.

  A slurry was prepared by kneading a piezoelectric powder containing lead zirconate titanate (PZT) in which a part of Zr was substituted with Sb, a binder, a dispersant, a plasticizer, and a solvent by ball mill mixing for 24 hours. .

  A green sheet was produced by the doctor blade method using the obtained slurry. An electrode paste containing Ag and Pd as an electrode material is applied to the green sheet in a predetermined shape by screen printing, and 12 layers of green sheets coated with the electrode paste are laminated, and the electrode paste is applied to the uppermost layer. One layer of green sheets not stacked was pressed and pressed to prepare a laminated molded body. And this laminated molded object was degreased in air | atmosphere for 1 hour at 500 degreeC, Then, it baked in air | atmosphere for 1100 degreeC for 3 hours, and obtained the laminated body.

  Next, both end surface portions in the longitudinal direction x of the obtained laminate are cut by dicing, the front ends of the internal electrode layers are exposed on the side surfaces of the laminate, and a surface electrode layer is formed on one main surface of the laminate. An electrode paste containing Ag and glass as an electrode material is applied to one side of the main surface of the laminate by screen printing, and then an electrode containing Ag and glass as an external electrode material on both side surfaces in the longitudinal direction x. The paste was applied by dip product application (dip method) and baked in the atmosphere at 700 ° C. for 10 minutes to produce an element body as shown in FIG.

  The element body was cut and removed by dicing as shown by a broken line in FIG. 5A to produce a multilayer piezoelectric element as shown in FIGS. 5B and 5C.

  The dimensions of the main surface of the produced laminate were 3.5 mm in width and 26 mm in length, the thickness of the piezoelectric layer was 30 μm, and the thickness of the internal electrode layer was 3 μm. The inactive layer is made of the same material as that of the piezoelectric layer, and the thickness thereof is 30 μm like the thickness of the piezoelectric layer. The total thickness of the laminate was about 440 μm.

  Next, polarization was performed by applying a voltage of 100 V for 2 minutes between the internal electrode layers and between the internal electrode layer and the surface electrode through the external electrodes of the multilayer piezoelectric element.

  Next, a 42 alloy (made of alloy) support plate having a thickness of 0.2 mm was prepared, an adhesive made of a thermosetting epoxy resin was applied to one main surface of the support plate, and the support plate coated with the adhesive was applied. The laminated piezoelectric element was pressed onto the part, and the adhesive was cured in air at 120 ° C. for 1 hour to form an adhesive layer on the bottom side having a thickness of 10 μm. Furthermore, a conductor layer was formed on the surface of the external electrode and electrically joined to the support plate, and 10 unimorph type vibrators were produced in which only one laminated piezoelectric element was joined to the support plate.

  With respect to 10 produced unimorph-type vibrators, when the insulation resistance between the support plate and the external electrodes of the multilayer piezoelectric element was measured, all 10 were 1 GΩ or more, and all of them had good insulation. Further, the produced unimorph type vibrating body was displaced by applying a voltage of 5 V to the vibrating body through an external electrode, and the amount of displacement was measured with a laser displacement meter, which was 18.4 to 18.6 μm. It was.

As a comparative example, 12 layers of green sheets coated with electrode paste are laminated, and one green sheet without electrode paste is laminated on top layer and pressed to produce a laminated molded body. After firing, the laminate was cut to produce a laminate. A multilayer piezoelectric element having surface electrode layers formed on both main surfaces of the multilayer body is formed, and the multilayer piezoelectric element is bonded to a support plate with an adhesive layer on the bottom surface side having a thickness of 25 μm. Ten unimorph type vibrators as shown in FIG.
For 10 produced unimorph-type vibrators, the insulation resistance between the support plate and the external electrodes of the multilayer piezoelectric element was measured. As a result, 2 out of 10 were 10 MΩ or less, and the insulation was low. Moreover, when the amount of displacement was measured similarly to the product of the present invention, it was 17.6 to 18 μm.

  In the same manner as in Example 1, 12 layers of green sheets coated with electrode paste were laminated, and one green sheet not coated with electrode paste was stacked and pressed on the top layer to produce a laminated molded body. . This laminated molded body was cut into a predetermined shape so that every other electrode pattern of the internal electrode layer was exposed on the side surface in the longitudinal direction, thereby producing a laminated molded body.

  And these laminated moldings were degreased in the air at 500 ° C. for 1 hour, and then fired in the air at 1100 ° C. for 3 hours to obtain a laminated body.

  Next, in order to form a surface electrode layer on one main surface of the laminate, an electrode paste containing Ag and glass as an electrode material is applied to the main surface of the laminate by screen printing, and then in the longitudinal direction x. An electrode paste containing Ag and glass as an external electrode material was applied to both sides by a dip method, and baked in the air at 700 ° C. for 10 minutes to produce a device body.

  This element body was cut and removed by dicing to produce a multilayer piezoelectric element as shown in FIGS.

  The dimensions of the main surface of the produced laminate were 3.5 mm in width and 26 mm in length, the thickness of the piezoelectric layer was 30 μm, and the thickness of the internal electrode layer 9 was 3 μm. The inactive layer is made of the same material as that of the piezoelectric layer, and the thickness thereof is 30 μm like the thickness of the piezoelectric layer. The total thickness of the laminate was about 440 μm.

  Next, polarization was performed by applying a voltage of 100 V for 2 minutes between the internal electrode layers and between the internal electrode layer and the surface electrode through the external electrodes of the multilayer piezoelectric element.

  Next, a 42 alloy (made of alloy) support plate having a thickness of 0.2 mm was prepared, an adhesive made of a thermosetting epoxy resin was applied to one main surface of the support plate, and the support plate coated with the adhesive was applied. The laminated piezoelectric element was pressed onto the part, and the adhesive was cured in air at 120 ° C. for 1 hour to form an adhesive layer on the bottom side having a thickness of 10 μm. Further, ten bimorph type vibrators were produced in which a conductor layer was formed on the surface of the external electrode and electrically joined to the support plate, and only one laminated piezoelectric element was joined to the support plate.

  When the side surface portion of the laminated body was observed, as shown in FIG. 6B, the shape of the side surface of the piezoelectric layer was an uneven shape reflecting the particle shape of the piezoelectric material. Further, the internal electrode layer did not reach the side surface of the laminate, and the external electrode was in a state of entering the opening of the internal electrode layer.

  Also in this case, when the insulation resistance between the support plate and the external electrode of the multilayer piezoelectric element was measured, all 10 pieces were 1 GΩ or more, and all the insulation properties were good. Moreover, when the amount of displacement was measured, the amount of displacement was 18.5-19 micrometers.

DESCRIPTION OF SYMBOLS 1, 3 ... Laminated piezoelectric element 5 ... Support plate 6 ... Bottom adhesive layer layer 7 ... Piezoelectric layer 9 ... Internal electrode layer 11 ... Inactive layer 13 ... Stack 15: surface electrode layers 17, 19 ... external electrode 20 ... element body 20a ... inclined surface x ... longitudinal direction c of main surface ... corner

Claims (4)

  Piezoelectric layers and internal electrode layers are alternately laminated, and a plate-like laminate having a pair of rectangular main surfaces and a pair of side surfaces provided at both ends in the longitudinal direction of the main surfaces; An element body comprising a pair of external electrodes provided on the pair of side surfaces of the multilayer body and electrically connected to the internal electrode layer, and one main surface and the side surface of the multilayer body, The laminated piezoelectric element is characterized in that the corner portion formed in (1) is obliquely cut and removed together with the external electrode formed on the side surface to form an inclined surface.   Piezoelectric layers and internal electrode layers are alternately laminated, and a plate-like laminate having a pair of rectangular main surfaces and a pair of side surfaces provided at both ends in the longitudinal direction of the main surfaces, A step of manufacturing an element body in which a pair of external electrodes that are electrically connected to the internal electrode layer are provided on the pair of side surfaces of the multilayer body, and one main surface and the side surface of the multilayer body, And a step of forming an inclined surface on the element body by obliquely cutting and removing the formed corner together with the external electrode formed on the side surface.   3. The laminate according to claim 2, wherein in the step of manufacturing the element body, a surface electrode layer electrically connected to one of the pair of external electrodes is formed on the other main surface of the laminate. Type piezoelectric element manufacturing method.   2. A vibrating body, wherein one main surface of the multilayer body of the multilayer piezoelectric element according to claim 1 is bonded to a support plate by an adhesive layer.

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