WO2012123156A1 - Composant actionneur piézoélectrique et procédé de fabrication d'un composant actionneur piézoélectrique - Google Patents

Composant actionneur piézoélectrique et procédé de fabrication d'un composant actionneur piézoélectrique Download PDF

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Publication number
WO2012123156A1
WO2012123156A1 PCT/EP2012/051227 EP2012051227W WO2012123156A1 WO 2012123156 A1 WO2012123156 A1 WO 2012123156A1 EP 2012051227 W EP2012051227 W EP 2012051227W WO 2012123156 A1 WO2012123156 A1 WO 2012123156A1
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WO
WIPO (PCT)
Prior art keywords
conductive layers
section
stack
layers
layer thickness
Prior art date
Application number
PCT/EP2012/051227
Other languages
German (de)
English (en)
Inventor
Christoph Auer
Reinhard Gabl
Original Assignee
Epcos Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Epcos Ag filed Critical Epcos Ag
Publication of WO2012123156A1 publication Critical patent/WO2012123156A1/fr

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Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/87—Electrodes or interconnections, e.g. leads or terminals
    • H10N30/871—Single-layered electrodes of multilayer piezoelectric or electrostrictive devices, e.g. internal electrodes
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/01—Manufacture or treatment
    • H10N30/06—Forming electrodes or interconnections, e.g. leads or terminals
    • H10N30/067—Forming single-layered electrodes of multilayered piezoelectric or electrostrictive parts
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/50—Piezoelectric or electrostrictive devices having a stacked or multilayer structure
    • H10N30/508—Piezoelectric or electrostrictive devices having a stacked or multilayer structure adapted for alleviating internal stress, e.g. cracking control layers

Definitions

  • the invention relates to a piezoelectric Aktorbauelement with piezoelectric layers, in which destruction by poling cracks can be largely prevented.
  • the invention further relates to a method for producing a piezoelectric Aktorbauelements with piezo ⁇ electrical layers, wherein destruction of the device by formation of poling cracks can be largely avoided.
  • a piezoelectric actuator component comprises a stack of stacked piezoelectric layers, which may be ceramic layers, for example. Between the ceramic layers, conductive layers are arranged as electrode layers for applying a voltage to the stack arrangement. First of the electrode layers extend from a first surface into the first
  • Second of the electrode layers extend from the second surface into the layer stack and end at a distance in front of the first surface.
  • poling cracks can form in the piezoelectric material of the isolation zone. These polarity cracks are caused by mechanical stresses in the isolation zone. The poling lead to Redukti ⁇ on the stress fields in the isolation zone.
  • the poling cracks at the interface between electrode layer and benachbar ⁇ ter ceramic layer within the ceramic layers form, or in specifically designated predetermined breaking locations. In the isolation zone, the cracks are generally parallel to the electrode plane. If the voltages at the electrode layers are too high, the poling cracks may increase depending on the electromechanical load.
  • a branching of the cracks can occur, in particular, at the transition from the isolation zone to the active region of the actuator. This entste ⁇ hen can within the stack conductive paths, as a result, may lead to component failure. It is desirable to provide a piezoelectric actuator device in which branching of the poling cracks into the piezoelectric material can be largely prevented. Furthermore, a method for producing a piezoelectric actuator component is to be specified, in which a Branching poling cracks in the piezoelectric material is largely prevented.
  • An embodiment of a piezoelectric actuator component comprises a plurality of conductive layers and a plurality of piezoelectric layers arranged one above the other in a stack.
  • the plurality of conductive layers are disposed between the piezoelectric layers.
  • At least one of the plurality of the conductive layers has a portion in a first layer thickness and at a white ⁇ direct section having a second layer thickness, the two ⁇ th layer thickness is greater than the first thickness.
  • the electrode design is characterized by the fact that the inner electrode layers in the transition region between the isolation zone and the active region are significantly thicker than in the active region.
  • the cooling after sintering due to the significantly smaller coefficient of thermal expansion of the piezoelectric or ceramic layers relative to the metallic layers of the electrodes, causes stresses to be set in the stack of ceramic material and electrode layers arranged therebetween.
  • the electrodes are claimed laterally, that is normal to the actuator axis, under train and the adjacent ceramic under pressure. Since the height of this pressure depends on the thickness of the Benach ⁇ disclosed electrode layers from above resulting guide shape of the piezoelectric Aktorbauelements to the fact that in the transition region isolation region / active region, the production-related lateral compressive stresses in the ceramic than in the other areas. As a result, tensile components occurring during operation are reduced. Thus, the tendency to divide the poling cracks can be significantly reduced or prevented altogether.
  • An embodiment of a method of manufacturing a piezoelectric actuator device includes providing a plurality of piezoelectric layers, coating each of the plurality of piezoelectric layers with a conductive layer by a printing method, particularly a screen printing method using a first template. Additional material of conductive
  • Layer is applied to at least one of the conductive layers in a subsequent printing process using a second template such that the at least one of the conductive layers has a first layer thickness in one section and a second layer thickness in another section, the second layer thickness being greater than that first layer thickness is.
  • the coated piezoelekt step ⁇ layers are stacked to form a stack one above the other and pressed. From the stack individual Aktorbau ⁇ parts can be isolated, which are then sintered to a dense body.
  • FIG. 1 shows an embodiment of a piezoelectric actuator component
  • Figure 2 shows a detail of an imple mentation form of a
  • FIG. 3A shows an embodiment of a piezoelectric actuator component for avoiding the branching of polarity cracks
  • FIG. 3B shows an enlarged view of an embodiment of a region of electrode layers with increased layer thickness
  • FIG. 4A is a further disclosed embodiment, a piezoelectric Aktuatorbauelements to avoid From ⁇ branching of polarization cracks,
  • FIG. 4B shows an enlarged view of an embodiment of a region of electrode layers with increased layer thickness
  • FIG. 5 is a graphic illustration for defining a hoop stress at a crack tip
  • FIG. 6 is a graph of a hoop stress as a function of
  • FIG. 7A is a disclosed embodiment, a method for the manufacture ⁇ development of an electrode layer on a piezoelekt ⁇ step layer
  • FIG. 7B shows an embodiment of a method for applying additional material on a conductive layer to form a region of the conductive layer with a higher layer thickness.
  • FIG. 1 shows an embodiment of a piezoelectric actuator component in which piezoelectric layers 30 are arranged one above the other in a stack 100. Between the piezoelectric layers 30, conductive layers 10, 20 are arranged, which in each case an inner electrode layer Neren in ⁇ In the stack 100 form. Electrode layers 10 extend from a surface 0100a into the piezoelectric layer stack and end at a distance in front of an opposing surface 0100b. Electrode layers 20 extend from the surface 0100b into the interior of the stack 100 and end at a distance in front of the surface 0100a. The electrode layers 10 are connected to each other via an outer metallization 41 for applying a voltage. The electrode layers 20 are connected to each other via an outer metallization 42 for applying a voltage.
  • the electrode layers 10 and 20 are arranged alternately in the layer stack 100 in the longitudinal direction of the actuator.
  • the ⁇ ggi areas of the stack 100 at which the electrical the layers 10 and 20 overlap provide the active area B0 of the actuator.
  • cracks can form at the interface between the electrode layer and the piezoelectric or ceramic layer.
  • the cracks in the isolati ⁇ onszone largely run parallel to the electrode plane.
  • the mechanical stress field of the layers stacked on top of each other has significant lateral stress components, that is, stress components normal to
  • FIG. 2 shows a detail of the piezoelectric actuator component of FIG. 1 with the electrode layers 10 and 20 extending from different sides of the stack 100 into the material of the ceramic 30.
  • the course of cracks R which may have arisen during polarity or during later operation of the component, is shown by dashed lines in the material of the piezoelectric layers 30.
  • the cracks extend from the surfaces 0100a or 0100b still largely parallel to the electrode layers, but then two ⁇ gen into the ceramic material 30th The cracks can penetrate the ceramic layers between two electrode planes and thus lead to the formation of conductive paths, which can result in device failure.
  • Whether a branching of the cracks occurs in the transition region between the insulation zone B1 and the active region B0 depends on the one hand on the individual main components of the stress field and thus on the electromechanical load. In particular, lateral, that is, normal to the actuator axis ver ⁇ current shares of the stress tensor promote the branching of Ris- se. On the other hand depends on the branching of cracks from the Inhomo ⁇ geneity of the strength, especially the distinction of a plane of weakness parallel to the internal electrodes decreases. In actuators in which the cracks between an electrode layer and a piezoelectric layer ausbil ⁇ den, the difference in the strength of this connection in comparison to the strength of the piezoelectric layer is very small. As a result, branching cracks frequently occur in these actuators even at low overvoltages.
  • FIGS. 3A and 4A each show an embodiment of a piezoelectric actuator component 1, 2 for avoiding the branching of poling cracks into the interior of the piezoelectric layers 30.
  • the actuator components 1 and 2 have a plurality of conductive layers 10, 20 and a multiplicity of piezoelectric layers 30 arranged one above the other in a stack 100.
  • the plurality of conductive layers 10, 20 are disposed between the piezoelectric layers 30.
  • At least one of the plurality of the conductive layers 10, 20 has, in a portion A0 of the at least one conductive layer having a first thickness and in another section, Al, A2, a second layer ⁇ thick, whereby the second layer thickness is greater than the first thickness.
  • the conductive layers 10 extend from a surface 100a of the stack 100 into the stack of piezoelectric layers and terminate at a distance d away from a surface 0100b of FIG
  • Conductive layers 20 extend from ⁇ continuously from the surface 0100b of the layer stack in the stack 100 into and terminate in the distance d in front of the Oberflä ⁇ che OlOOa.
  • the first and second conductive layers form the electrode layers to which a voltage potential can be applied.
  • the electrode layers 10 may, for example, 41 interconnected by a mounted on the surface 0100amidstmetalli ⁇ tion.
  • the electrode layers 20 can be electrically connected to one another by an outer metallization 42 applied to the surface 0100b.
  • FIGS. 3A and 4B Those regions within the layer stack 100 of FIGS. 3A and 4B, on which the electrode layers 10 and 20 overlap, form the active region of the actuator, which undergoes a change in length when a voltage is applied to the electrode layers 10 and 20.
  • the edge regions between the surface 0100a and the active region B0 and the edge regions between the surface 0100b and the active region B0 represent the isolation zones B1. In the region of the isolation zones B1, no deflection occurs when an external voltage is applied to the actuator component.
  • Figure 3B shows the section of AI one of the conductive layers 10 having the increased thickness compared to the portion A0 of the conductive layer 10 in a ver ⁇ recreationalten representation.
  • the Layer 10 has a partial section TAI which lies between a position PlOa and a position PlOb of the conductive layer 10.
  • the position PlOa is located at the distance d from the surface 0100a.
  • the position PlOb lies between the position PlOa and the surface 0100a.
  • the section AI of the conductive layer 10 has a partial section TA2 that lies between the position PlOa and a position PlOc of the conductive layer 10.
  • the position PlOc lies between the position PlOa and the surface 0100b of the layer stack.
  • the section AI of the conductive Layer further comprises a subsection TA3.
  • the subsection TA3 lies between the position PlOb and the surface 0100a of the layer stack.
  • Figure 3B further shows the section AI one of the conductive layers 20, which is arranged adjacent in the layer stack to the conductive layer 10, in a magnification ⁇ ßerten representation.
  • the conductive layer 20 has an increased layer thickness compared to its remaining section A0.
  • Layer 20 comprises a section TAI that is between ei ⁇ ner position P20a and P20b a position of the conductive layer twentieth
  • the position P20a is away from the surface 0100b of the layer stack at the distance d.
  • the position P20b lies between the position P20a and the surface 0100b of the layer stack.
  • the section AI of the conductive layer 20 has a part ⁇ section TA2 and a section TA3.
  • the subsection TA2 is located between the position P20a and a position P20c of the conductive layer 20.
  • the position P20c is between the position P20a and the surface 0100a.
  • the partial section TA3 lies between the position P20b and the surface 0100b of the layer stack.
  • the two can be up to four times the layer thickness of the portion ⁇ A0.
  • the electrode layers 10 and 20 may, for example, have a layer thickness between 1 ⁇ and 3 ⁇ . In the thickened area, the Electrode layers have a layer thickness between 2 ⁇ and 12 ⁇ on.
  • the material of the conductive layers 10 and 20 may be the same material in section AI as in section A0.
  • the conductive layers 10 and 20 but also in comparison with the section A0 of a different material ⁇ composition. It is also possible to use the same materials with different mixing ratios for section AI and section A0.
  • FIGS. 4A and 4B show a further embodiment of a piezoelectric actuator component 2 for avoiding branching poling cracks in the transition region between active region B0 and inactive region B1.
  • a section A2 of the thickened internal electrode region only partially extends in the isolation zone B1 and in the active region B0.
  • the portion A2 of the increased layer thickness is not sufficient, especially in the isolation zone Bl up to the upper ⁇ surfaces 0100a and 0100b of the layer stack.
  • FIG. 4B shows the conductive layers 10 and 20 with the sections A2 of the increased layer thickness in an enlarged representation.
  • the conductive layers 10 and 20 in the sections A2 have only the partial section TAI and the partial section TA2.
  • Layer 10 is disposed between the position and the position PlOa Plop the conductive layer 10, wherein the positi on PlOa ⁇ d is removed from the surface 0100a in the distance and the position between the position Plop PlOa and the surface 0100a lies.
  • the section of the TA2 leitfä ⁇ ELIGIBLE layer 10 is located between the position and a position PlOa Ploc the conductive layer 10, whereby the position between the position Ploc PlOa and the surface 0100b of the layer stack is located.
  • Layer 20 is disposed between a position P20a and P20b a position of the conductive layer 10, wherein the position P20a is d from the surface 0100b ent ⁇ removed in the distance and the position is located between the position P20b PlOa and the surface 0100b.
  • the partial section TA2 of the conductive layer 20 lies between the position P20a and a position P20c of the conductive layer 20, the position P20c between the position P20a and the surface
  • the positions PlOb, P20b and the positions PlOc, P20c are less than the distance d of the isolation zone from the position PlOa, P20a.
  • all of the conductive layers 10 and 20 have the increased layer thickness in their respective sections A2 in comparison to their respective sections A0.
  • the increased layer thickness can be two to four times the layer thickness in the section A0.
  • the electrode layers 10 and 20 may, for example, have a layer thickness between 1 ⁇ and 3 ⁇ . In the thickened region, the electrode layers have a layer thickness between 2 ⁇ and 12 ⁇ on.
  • the conductive layers 10 and 20 may comprise the same material as in section A0.
  • Ab ⁇ section A2 can also be a different material than in section A0, in particular a material with a different composition tion or another mixing ratio, ver ⁇ be used.
  • Circular arc with radius r around the crack tip describes the so-called hoop stress Scp in the direction of the vector e_cp.
  • the crack propagation direction is determined in the linear elastic case and in homogeneous fracture toughness of the material by an angle ⁇ for which the circumference stress is maximal.
  • FIG. 6 shows the simulation results of the hoop stress as a function of the angle ⁇ .
  • the simulations WUR ⁇ performed for a piezoelectric actuator of a single layer thickness in the portion A2 and a two-fold or three-fold increase in film thickness under overload conditions with an E-field of 3 kV / mm and an axial prestress of 20 MPa.
  • the results show that under these conditions conditions having at a actuator device, in which the electrodes ⁇ layers in the sections A0 and A2 a uniform layer thickness, the hoop stress becomes maximum at approximately ⁇ 60 °. At this angle, a branching of the poling cracks is to be expected for isotropic fracture toughness.
  • the graph of FIG. 6 further shows that the voltage field at the crack tip changes parallel to the crack direction due to the compression of the electrode and ceramic during the sintering of the internal electrodes due to the reinforcement of the internal electrodes.
  • the course of the hoop stress for twofold and in particular for triple electrode thickness shows that, on account of the increased layer thickness in sections AI and A2, the danger of branching of poling cracks is markedly reduced.
  • FIGS. 7A and 7B show a method of manufacturing the conductive layers 10, 20 on the piezoelectric layer 30 of a piezoelectric actuator device. For the sake of simplicity, only one of the plurality of piezoelectric layers 30 is shown, which is coated with an electrode layer 10 or 20, respectively.
  • FIG. 7A the coating of the piezoelectric layer 30 with the conductive layer 10, 20 takes place by printing the ceramic film 30 with a conductive material of the electrode layer, in particular by means of a screen printing method , using a template S1.
  • FIG. 7B shows the application of additional material for the electrode layers 10, 20 in sections AI and A2, respectively. The application of the additional material takes place in a subsequent printing process using a further stencil S2. The so coated Piezoelectric layers 30 are then stacked and sintered to stacking assembly 100.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)
  • Fuel-Injection Apparatus (AREA)

Abstract

L'invention concerne un composant actionneur piézoélectrique comprenant une pluralité de couches conductrices (10, 20) et une pluralité de couches piézoélectriques (30) disposées les unes sur les autres en formant un empilement (100), la pluralité de couches conductrices (10, 20) étant disposée entre les couches piézoélectriques. Au moins une parmi la pluralité de couches conductrices (10, 20) présente, dans une section (A0), une première épaisseur de couche et, dans une autre section (A1, A2), une deuxième épaisseur de couche, la deuxième épaisseur de couche étant supérieure à la première épaisseur de couche.
PCT/EP2012/051227 2011-03-17 2012-01-26 Composant actionneur piézoélectrique et procédé de fabrication d'un composant actionneur piézoélectrique WO2012123156A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102011014296.7 2011-03-17
DE102011014296A DE102011014296A1 (de) 2011-03-17 2011-03-17 Piezoelektrisches Aktorbauelement und Verfahren zur Herstellung eines piezoelektrischen Aktorbauelements

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WO2012123156A1 true WO2012123156A1 (fr) 2012-09-20

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WO (1) WO2012123156A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102012110556B4 (de) * 2012-11-05 2014-07-03 Epcos Ag Vielschichtbauelement und Verfahren zu dessen Herstellung

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08148731A (ja) * 1994-11-21 1996-06-07 Sumitomo Metal Ind Ltd 積層型圧電アクチュエータ
WO2000079615A1 (fr) * 1999-06-19 2000-12-28 Robert Bosch Gmbh Piezo-actionneur
DE10257952A1 (de) * 2002-12-12 2004-07-01 Robert Bosch Gmbh Piezoaktor und ein Verfahren zu dessen Herstellung
WO2010024277A1 (fr) * 2008-08-28 2010-03-04 京セラ株式会社 Élément piézoélectrique multicouches, appareil d’injection et système d’injection de carburant

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1314007A (zh) * 1999-06-23 2001-09-19 罗伯特·博施有限公司 用于柴油喷射装置的带防裂设施的压电式多层致动器及制造它的方法
DE10112588C1 (de) * 2001-03-15 2002-05-02 Siemens Ag Piezoaktor sowie Verfahren zur Herstellung eines Piezoaktors

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08148731A (ja) * 1994-11-21 1996-06-07 Sumitomo Metal Ind Ltd 積層型圧電アクチュエータ
WO2000079615A1 (fr) * 1999-06-19 2000-12-28 Robert Bosch Gmbh Piezo-actionneur
DE10257952A1 (de) * 2002-12-12 2004-07-01 Robert Bosch Gmbh Piezoaktor und ein Verfahren zu dessen Herstellung
WO2010024277A1 (fr) * 2008-08-28 2010-03-04 京セラ株式会社 Élément piézoélectrique multicouches, appareil d’injection et système d’injection de carburant
EP2337104A1 (fr) * 2008-08-28 2011-06-22 Kyocera Corporation Élément piézoélectrique multicouches, appareil d injection et système d injection de carburant

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