Piezoelectric/electrostrictive device Number:7,402,936 from the United States Patent and Trademark Office (PTO) owispatent A piezoelectric/electrostrictive device is provided with a stationary portion, a thin-plate portion supported by the stationary portion, and piezoelectric/electrostrictive element formed by alternately laminating a plurality of electrodes and a plurality of piezoelectric/electrostrictive layers. The piezoelectric/electrostrictive device is produced by cutting a thin-plate body that composes the thin-plate portion afterward and a laminated body comprising the piezoelectric/electrostrictive layers and thereafter applying prescribed specific processing (for example, heat treatment) to the cut plane (the lateral end surfaces). By so doing, the ratio of the actual surface area of the lateral end surface of the piezoelectric/electrostrictive element to the area of the lateral end surface of the piezoelectric/electrostrictive element in the orthographic projection is four or less, and the deposition of moisture on the lateral end surfaces is suppressed to the extent of not substantially generating electric leakage or ion migration. As a result, a highly durable piezoelectric/electrostrictive device can be provided.<H electrostrictive, Piezoelectric, Piezoelectric, e, 7402936.html, Patent, pto, 7402936

Title: Piezoelectric/electrostrictive device

Abstract: A piezoelectric/electrostrictive device is provided with a stationary portion, a thin-plate portion supported by the stationary portion, and piezoelectric/electrostrictive element formed by alternately laminating a plurality of electrodes and a plurality of piezoelectric/electrostrictive layers. The piezoelectric/electrostrictive device is produced by cutting a thin-plate body that composes the thin-plate portion afterward and a laminated body comprising the piezoelectric/electrostrictive layers and thereafter applying prescribed specific processing (for example, heat treatment) to the cut plane (the lateral end surfaces). By so doing, the ratio of the actual surface area of the lateral end surface of the piezoelectric/electrostrictive element to the area of the lateral end surface of the piezoelectric/electrostrictive element in the orthographic projection is four or less, and the deposition of moisture on the lateral end surfaces is suppressed to the extent of not substantially generating electric leakage or ion migration. As a result, a highly durable piezoelectric/electrostrictive device can be provided.

Patent Number: 7,402,936 Issued on 07/22/2008 to Ikeda, et al.

Inventors: Ikeda; Koji (Tsu, JP), Kikuta; Yuya (Nagoya, JP), Noguchi; Nobuchika (Ichinomiya, JP), Kitamura; Kazumasa (Ichinomiya, JP), Shibata; Kazuyoshi (Mizunami, JP)
Assignee: NGK Insulators, Ltd. (Nagoya, JP)

Appl. No.: 11/738,753

Filed: April 23, 2007

Related U.S. Patent Documents


Application Number	Filing Date	Patent Number	Issue Date
PCT/JP2005/019443	Oct., 2005

Foreign Application Priority Data


Oct 25, 2004 [JP]			2004-310023
Dec 10, 2004 [JP]			2004-358874
Jan 17, 2005 [JP]			2005-008505
Mar 17, 2005 [JP]			2005-077383

Current U.S. Class: 310/328 ; 310/332

Current International Class: H01L 41/08 (20060101)

Field of Search: 310/324,328,330-332

References Cited [Referenced By]

U.S. Patent Documents


5281899	January 1994	Culp
7071599	July 2006	Namerikawa et al.
2002/0017830	February 2002	Ikeda et al.
2003/0234595	December 2003	Takahashi et al.
2004/0185278	September 2004	Sato
2005/0248235	November 2005	Namerikawa et al.
2006/0207078	September 2006	Namerikawa et al.

Foreign Patent Documents


06-252469	Sep., 1994	JP
2000-082931	Mar., 2000	JP
2001-320103	Nov., 2001	JP
2002-117637	Apr., 2002	JP
2002-299713	Oct., 2002	JP
2003-047923	Feb., 2003	JP
2004-137106	May., 2004	JP
2004-282053	Oct., 2004	JP

Primary Examiner: Dougherty; Thomas M
Attorney, Agent or Firm: Burr & Brown

Claims

The invention claimed is:

1. A piezoelectric/electrostrictive device, comprising: a thin-plate portion; a stationary portion that supports the thin-plate portion; and a piezoelectric/electrostrictive element which is formed by laminating a plurality of electrodes and at least one piezoelectric/electrostrictive layer at least on a plane of the thin-plate portion and has a lateral end surface formed with the respective lateral end surfaces of the plurality of electrodes and the lateral end surface of the at least one piezoelectric/electrostrictive layer, the device being formed by applying curved surface forming and/or chamfering to a corner of the lateral end surface of the piezoelectric/electrostrictive element; and having the surface roughness of a planar portion of the lateral end surface of the piezoelectric/electrostrictive element finished into 1 .mu.m or less in terms of Ra by polishing, wherein the subsequent heating process is repeatedly applied twice or more.

2. The piezoelectric/electrostrictive device according to claim 1, wherein the heating process repeated twice or more is applied in a temperature range of 600.degree. C. or lower.

3. A piezoelectric/electrostrictive device, comprising: a thin-plate portion; a stationary portion that supports the thin-plate portion; and a piezoelectric/electrostrictive element which is formed by laminating a plurality of electrodes and at least one piezoelectric/electrostrictive layer at least on a plane of the thin-plate portion and has a lateral end surface formed with the respective lateral end surfaces of the plurality of electrodes and the lateral end surface of the at least one piezoelectric/electrostrictive layer, the device being formed by applying curved surface forming and/or chamfering to a corner of the lateral end surface of the piezoelectric/electrostrictive element; and having the surface roughness of a planar portion of the lateral end surface of the piezoelectric/electrostrictive element finished into 1 .mu.m or less in terms of Ra by polishing, wherein the subsequent heating process is applied in the temperature range of 800.degree. C. to 1,000.degree. C.

Description

TECHNICAL FIELD

The present invention relates to a piezoelectric/electrostrictive device including a stationary portion, a thin-plate portion supported by the stationary portion, and a piezoelectric/electrostrictive element including laminar electrodes and a piezoelectric/electrostrictive layer.

BACKGROUND ART

Piezoelectric/electrostrictive devices of the above-described type have been actively developed as an actuator for precision machining; as an actuator for controlling the position of a read and/or write element (e.g., a magnetic head of a hard disk drive) for reading and/or writing optical information, magnetic information, or the like; as a sensor for converting mechanical vibration to an electrical signal; or as a similar device.

Japanese Patent Application Laid-Open (kokai) No. 2001-320103 discloses an example of such a piezoelectric/electrostrictive device, which is shown in FIG. 13. The piezoelectric/electrostrictive device includes a stationary portion 100; thin-plate portions 110 supported by the stationary portion 100; holding portions (movable portions) 120 provided at corresponding tip ends of the thin-plate portions 110 and adapted to hold an object (e.g., a magnetic head of a hard disk drive); and piezoelectric/electrostrictive elements 130 formed at least on corresponding surfaces of the thin-plate portions 110, each piezoelectric/electrostrictive element 130 including a plurality of electrodes and a plurality of piezoelectric/electrostrictive layers which are laminated alternately. In the piezoelectric/electrostrictive device, an electric field is generated between electrodes of the piezoelectric/electrostrictive elements 130 to thereby expand and contract the piezoelectric/electrostrictive layers of the piezoelectric/electrostrictive elements 130, whereby the thin-plate portions 110 are deformed. The deformation of the thin-plate portions 110 causes displacement of the holding portions 120 (accordingly, displacement of the object held by the holding portions 120).

The piezoelectric/electrostrictive device of FIG. 13 is manufactured as follows. Firstly, as shown in FIG. 14, a plurality of ceramic green sheets (and/or a ceramic green sheet laminate) are prepared. As shown in FIG. 15, these ceramic green sheets are laminated together and then fired, thereby forming a ceramic laminate 200. As shown in FIG. 16, piezoelectric/electrostrictive laminates 210, each including a plurality of electrodes and a plurality of piezoelectric/electrostrictive layers which are laminated alternately, are formed on the surface of the ceramic laminate 200. Through wire sawing (or, for example, dicing) by use of a wire saw WS, the piezoelectric/electrostrictive laminates 210 are cut along cutting lines C1 to C4 shown in FIG. 17, thereby yielding the piezoelectric/electrostrictive device.

Meanwhile, in the case where the above-disclosed piezoelectric/electrostrictive device is actually used (for example, in the case where the device is used as an actuator for the positioning of the magnetic head of a hard disk drive), moisture may sometimes deposit on lateral end surfaces (cut planes along the cutting line C3 or C4 in FIG. 17) of piezoelectric/electrostrictive elements 130. Such moisture can be caused by, for example, condensation or the like of water vapor in an atmosphere (in the air).

When moisture deposits on lateral end surfaces of piezoelectric/electrostrictive elements 130 (particularly on lateral end surfaces of piezoelectric/electrostrictive layers as parts of lateral end surfaces of piezoelectric/electrostrictive elements 130), the electric resistance of the piezoelectric/electrostrictive layers on the lateral end surfaces of which moisture has deposited lowers and thereby electric leakage tends to occur between the electrodes on both the sides that interpose the respective piezoelectric/electrostrictive layers. Otherwise, so-called ion migration is promoted on the lateral end surfaces of the piezoelectric/electrostrictive layers due to the existence of the moisture that deposits on the lateral end surfaces and, as a result, short circuit tends to occur between the electrodes on both the sides that interpose the respective piezoelectric/electrostrictive layers on the lateral end surfaces of which the moisture has deposited.

When such electric leakage occurs, voltage between the electrodes lowers and thereby the strength of the electric field formed between the electrodes weakens. As a result, the amount of the expansion and contraction of the piezoelectric/electrostrictive layers reduces and the piezoelectric/electrostrictive elements 130 (namely the piezoelectric/electrostrictive device) cannot attain intended operations. Further, when such short circuit occurs, voltage is not generated between the electrodes, thereby the piezoelectric/electrostrictive elements 130 do not expand or contract, and as a result the piezoelectric/electrostrictive elements 130 (namely the piezoelectric/electrostrictive device) cannot operate.

In addition, when such an above-disclosed piezoelectric/electrostrictive device is used as, for example, an actuator for the positioning of the magnetic head of a hard disk drive, the attachment of debris, dust, or the like on a hard disk, etc., may cause incorrect reading/writing of information. Hence, the piezoelectric/electrostrictive device is to be placed in an environment where the generation of debris, dust, or the like (the generation of debris, dust, or the like may hereunder be referred to as "dust generation" occasionally) can be suppressed to a lowest possible level.

In such a case, the above-disclosed piezoelectric/electrostrictive device is used in the state where the lateral end surfaces (cut planes along the cutting line C3 or C4 in FIG. 17), constituting a single planar plane, of the device face the surface of the hard disk with a relatively small gap in between and hence it is particularly necessary to prevent dust generation caused by the separation of microparticles (the separation of microparticles may hereunder be referred to as "particle separation" occasionally) from the lateral end surfaces (cut planes along the cutting line C3 or C4 in FIG. 17) of the constituent elements constituting the lateral end surfaces of the piezoelectric/electrostrictive device. From the above viewpoint, test items related to dust generation have been added to such a piezoelectric/electrostrictive device in recent years.

In view of the above situation, the above-disclosed piezoelectric/electrostrictive device is required to effectively suppress the deposition of moisture on the lateral end surfaces of piezoelectric/electrostrictive elements 130 and dust generation from the lateral end surfaces when the piezoelectric/electrostrictive device is actually used.

DISCLOSURE OF THE INVENTION

In view of the above situation, an object of the present invention is to provide a piezoelectric/electrostrictive device which can effectively suppress the deposition of moisture on the lateral end surfaces of piezoelectric/electrostrictive elements and dust generation from the lateral end surfaces.

In order to attain the above object, the present invention provides a piezoelectric/electrostrictive device comprising: thin-plate portions; a stationary portion that supports the thin-plate portions; and piezoelectric/electrostrictive elements each of which is formed by laminating a plurality of electrodes and at least one piezoelectric/electrostrictive layer at least on a plane of each of the thin-plate portions and has lateral end surfaces formed with the respective lateral end surfaces of the plurality of electrodes and the lateral end surfaces of the at least one piezoelectric/electrostrictive layer, wherein the ratio of the actual surface area of the lateral end surfaces of the piezoelectric/electrostrictive elements to the area of the lateral end surfaces of the piezoelectric/electrostrictive elements in the orthographic projection is four or less.

In general, when moisture deposits on a surface, the moisture tends to hardly deposit as the actual surface area of the surface (namely, the total surface area obtained by three-dimensionally taking all the large and small bumps and dips on the surface into consideration) reduces. Hence, it can be said that moisture tends to hardly deposit on the lateral end surfaces of a piezoelectric/electrostrictive element as the actual surface area of the lateral end surfaces reduces.

Further, the reduction of the actual surface area of the lateral end surfaces of a piezoelectric/electrostrictive element leads to the reduction of the ratio of the actual surface area of the lateral end surfaces of the piezoelectric/electrostrictive element to the area of the lateral end surfaces of the piezoelectric/electrostrictive element in the orthographic projection (hereunder referred to as "surface area increase rate").

Here, the present inventors have found that, when such a piezoelectric/electrostrictive device is actually used under ordinary service conditions, the deposition of moisture to the lateral end surfaces of the piezoelectric/electrostrictive device is suppressed to the extent of not substantially generating the aforementioned electric leakage and ion migration as long as the surface area increase rate of the lateral end surfaces of the piezoelectric/electrostrictive elements is "four" or less.

In addition, the present inventors have found that the actual surface area (namely, surface area increase rate) of the lateral end surfaces of a piezoelectric/electrostrictive element strongly correlates with the extent of the particle separation from the lateral end surfaces and the particle separation (namely, dust generation) from the lateral end surfaces can effectively be suppressed as long as the surface area increase rate is "four" or less.

Hence, by the above configuration, it is possible to effectively suppress the deposition of moisture onto the lateral end surfaces of a piezoelectric/electrostrictive element and dust generation from the lateral end surfaces. As a result, the intended operation of the piezoelectric/electrostrictive device is maintained for a long period of time. In other words, it is possible to provide a highly-durable piezoelectric/electrostrictive device. In addition, it is possible to provide a piezoelectric/electrostrictive device which can be used in an environment where dust generation should be avoided to the utmost.

In general, when the lateral end surfaces of a piezoelectric/electrostrictive element is formed (finished) by only machining or the like such as wire sawing, dicing, or the like, the surface area increase rate of the lateral end surfaces of the piezoelectric/electrostrictive element is larger than "four." in order to provide a piezoelectric/electrostrictive device according to the present invention, therefore, the production method including, in addition to the process of cutting the laminated body comprising electrodes and piezoelectric/electrostrictive layers, the process of forming (finishing) the lateral end surfaces of a piezoelectric/electrostrictive element so that the prescribed specific processing may be applied to the cut planes formed by the cutting and thereby the surface area increase rate of the lateral end surfaces may be four or less is actually adopted.

That is, the present invention, by such a production method, can provide a piezoelectric/electrostrictive device, wherein the lateral end surfaces of piezoelectric/electrostrictive elements are formed by applying prescribed specific processing to cut planes formed by cutting the laminated body comprising electrodes and piezoelectric/electrostrictive layers.

The specific processing is preferably any one of the processing of applying YAG laser processing to the cut planes, the processing of applying excimer laser processing to the cut planes, the processing of applying blasting to the cut planes, the processing of applying ultrasonic cleaning to the cut planes, the processing of applying heating to the cut planes in a furnace (namely, heat treatment), and the processing of applying polishing to the cut planes (or an arbitrary combination of two or more kinds of the processing).

By adopting any one of the above processing (or a combination of two or more kinds of the processing) as the above specific processing, it is possible to surely control the surface area increase rate of the lateral end surfaces of a piezoelectric/electrostrictive element to "four" or less through relatively simple treatment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a piezoelectric/electrostrictive device according to an embodiment of the present invention.

FIG. 2 is an enlarged fragmental front view showing the piezoelectric/electrostrictive device of FIG. 1.

FIG. 3 is a perspective view showing a modification of the piezoelectric/electrostrictive device of FIG. 1.

FIG. 4 is a perspective view showing ceramic green sheets to be laminated in a method for manufacturing a piezoelectric/electrostrictive device according to the present invention.

FIG. 5 is a perspective view showing a ceramic green sheet laminate formed by laminating and compression-bonding the ceramic green sheets of FIG. 4.

FIG. 6 is a perspective view showing a ceramic laminate formed by monolithically firing the ceramic green sheet laminate of FIG. 5.

FIG. 7 is a perspective view showing the ceramic laminate of FIG. 6 on which piezoelectric/electrostrictive laminates are formed.

FIG. 8 illustrates a step of cutting the ceramic laminate and the piezoelectric/electrostrictive laminates shown in FIG. 7.

FIG. 9 is a graph showing the data on the ratios of the surface area increase rates of the lateral end surfaces of respective piezoelectric/electrostrictive elements with regard to respective test samples subjected to respective specific processing according to the present invention and a test sample before subjected to the specific processing.

FIG. 10 is a graph showing the data on dielectric resistance between the electrodes of respective piezoelectric/electrostrictive elements with regard to respective test samples subjected to respective specific processing according to the present invention and a test sample before subjected to the specific processing.

FIG. 11 is a graph showing the data on the number of particles separated from the lateral end surfaces of respective piezoelectric/electrostrictive elements with regard to respective test samples subjected to respective specific processing according to the present invention and a test sample before subjected to the specific processing.

FIG. 12 is a perspective view showing yet another modification of the piezoelectric/electrostrictive device of FIG. 1.

FIG. 13 is a perspective view showing a conventional piezoelectric/electrostrictive device.

FIG. 14 is a perspective view showing ceramic green sheets to be laminated in the process of manufacturing the piezoelectric/electrostrictive device of FIG. 13.

FIG. 15 is a perspective view showing a ceramic laminate formed by monolithically firing a ceramic green sheet laminate formed by laminating and compression-bonding the ceramic green sheets of FIG. 14.

FIG. 16 is a perspective view showing the ceramic laminate of FIG. 15 on which piezoelectric/electrostrictive laminates are formed.

FIG. 17 illustrates a step of cutting the ceramic laminate and the piezoelectric/electrostrictive laminates shown in FIG. 16.

FIG. 18A is a view showing the orientation of the attachment of works on a round lap jig in a conventional case.

FIG. 18B is a view showing the orientation of the attachment of works on a round lap jig according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of piezoelectric/electrostrictive devices according to the present invention are hereunder explained in reference to drawings. A piezoelectric/electrostrictive device 10 according to the present embodiment shown as a perspective view in FIG. 1 comprises: a stationary portion 11 of a rectangular solid; a pair of thin-plate portions 12 being supported with the stationary portion 11 so as to stand from the stationary portion and facing each other; holding portions (movable portions) 13 formed at the insides on the tip side from the protrusions 12a formed at the insides in the vicinities of the tips of the thin-plate portions 12; and piezoelectric/electrostrictive elements 14 formed at least on respective outer planes of the thin-plate portions 12 by alternately laminating laminar electrodes and piezoelectric/electrostrictive layers. The outline of such a configuration is disclosed in, for example, Japanese Patent Application Laid-Open (kokai) No. 2001-320103.

The piezoelectric/electrostrictive device 10 retains an object (not shown in the figure), for example, by adhering the object between the pair of the holding portions 13 with an adhesive, deforms the thin-plate portions 12 by the force generated by the piezoelectric/electrostrictive elements 14, thereby displaces the holding portions 13, and thereby can be used as an actuator to be able to control the position of the object. That is, the protrusions 12a have the function of regulating the region where the adhesive is used. The object is a magnetic head, an optical head, a weight for gain control as a sensor, or the like.

A portion (also generically called a "substrate portion") constituted by the stationary portion 11, the thin-plate portions 12, and the holding portions 13 is formed of a ceramic laminate, which is formed by firing a laminate of ceramic green sheets as will be described below in detail. Such a monolithic ceramic element does not employ an adhesive for joining its portions and is thus almost free from a change in state with passage of time, thereby providing a highly reliable joint and having advantage in terms of attainment of rigidity. The ceramic laminate can be readily manufactured by a ceramic green sheet lamination process, which will be described below.

The entirety of the substrate portion may be formed from a ceramic material or a metal, or may assume a hybrid structure in which a ceramic material and a metal are employed in combination. Also, the substrate portion may be configured such that ceramic pieces are bonded together by means of an adhesive, such as an organic resin or glass, or such that metallic pieces are joined together through brazing, soldering, eutectic bonding, diffusion joining, welding, or a similar technique.

As shown in the enlarged view of FIG. 2, the piezoelectric/electrostrictive element 14 is formed on an outer wall surface (outer surface) formed by the stationary portion 11 (or a portion of the stationary portion) and the thin-plate portion 12 (or a portion of the thin-plate portion), includes a plurality of laminar electrodes and a plurality of piezoelectric/electrostrictive layers, and assumes the form of a laminate in which the laminar electrodes and the piezoelectric/electrostrictive layers are laminated alternately. The electrode layers and the piezoelectric/electrostrictive layers are parallel to the surface of the thin-plate portion 12. More specifically, the piezoelectric/electrostrictive element 14 is a laminate in which an electrode 14a1, a piezoelectric/electrostrictive layer 14b1, an electrode 14a2, a piezoelectric/electrostrictive layer 14b2, an electrode 14a3, a piezoelectric/electrostrictive layer 14b3, an electrode 14a4, a piezoelectric/electrostrictive layer 14b4, and an electrode 14a5 are laminated in that order on the outer surface of the thin-plate portion 12. The electrodes 14a1, 14a3, and 14a5 are electrically connected together and are insulated from the electrically connected electrodes 14a2 and 14a4. In other words, the electrically connected electrodes 14a1, 14a3, and 14a5 and the electrically connected electrodes 14a2 and 14a4 are arranged in a shape resembling the teeth of a comb.

The piezoelectric/electrostrictive element 14 is formed integrally with the substrate portion by a film formation process, which will be described below. Alternatively, the piezoelectric/electrostrictive element 14 may be manufactured separately from the substrate portion, followed by a process of joining the piezoelectric/electrostrictive element 14 to the substrate portion by use of an adhesive, such as an organic resin, or by means of glass, brazing, soldering, eutectic bonding, or a similar technique.

The present embodiment shows a multi-layered structure including five electrode layers; however, no particular limitation is imposed on the number of layers. In general, as the number of layers increases, a force (drive force) for deforming the thin-plate portions 12 increases, but power consumption also increases. Accordingly, the number of layers can be appropriately determined in accordance with, for example, application and the state of use.

A supplementary description of component elements of the piezoelectric/electrostrictive device 10 will next be given below.

The holding portions 13 operate on the basis of displacement of the thin-plate portions 12. Various members are attached to the holding portions 13 in accordance with applications of the piezoelectric/electrostrictive device 10. For example, when the piezoelectric/electrostrictive device 10 is employed as an element (displacing element) for displacing an object, particularly when the piezoelectric/electrostrictive 10 is employed for positioning or suppressing wringing of a magnetic head of a hard disk drive, a slider having a magnetic head, a magnetic head, a suspension having a slider, or a similar member (i.e., a member required to be positioned) may be attached. Also, the shield of an optical shutter or the like may be attached.

As described above, the stationary portion 11 is adapted to support the thin-plate portions 12 and the holding portions 13. When the piezoelectric/electrostrictive device 10 is employed for, for example, positioning the magnetic head of a hard disk drive, the stationary portion 11 is fixedly attached to a carriage arm attached to a VCM (voice coil motor), to a fixture plate attached to the carriage arm, to a suspension, or to a similar member. In some cases, unillustrated terminals and other members for driving the piezoelectric/electrostrictive elements 14 are provided on the stationary portion 11. The terminals may have a width similar to that of the electrodes or may be narrower or partially narrower than the electrodes. No particular limitation is imposed on the material for forming the holding portions 13 and the stationary portion 11, so long as the holding portions 13 and the stationary portion 11 have rigidity. In general, employment of a ceramic material as the material for these portions is preferred, since a ceramic green sheet lamination process, which will be described below, can be applied. Specific examples of the material include a material containing, as a primary component, zirconia (such as stabilized zirconia or partially stabilized zirconia), alumina, magnesia, silicon nitride, aluminum nitride, or titanium oxide; and a material containing a mixture of them as a primary component. A material containing, as a primary component, zirconia (in particular, stabilized zirconia or partially stabilized zirconia) is preferred for the piezoelectric/electrostrictive device 10, since such a material has high mechanical strength and toughness. When a metallic material is to be employed for manufacturing the holding portions 13 and the stationary portion 11, stainless steel, nickel, or the like is preferred as the metallic material.

As described above, the thin-plate portions 12 are driven by the piezoelectric/electrostrictive elements 14. The thin-plate portions 12 are thin-plate-like members having flexibility and have a function for converting expansion/contraction displacement of the piezoelectric/electrostrictive elements 14 disposed on their surfaces to bending displacement and transmitting the bending displacement to the corresponding holding portions 13. Accordingly, no particular limitation is imposed on the shape of and the material for the thin-plate portions 12, so long as the thin-plate portions 12 are flexible and have such mechanical strength as not to be broken from bending deformation; and the shape and material are selected in view of, for example, response and operability of the holding portions 13.

The thickness Dd (see FIG. 1) of the thin-plate portion 12 is preferably about 2 .mu.m to about 100 .mu.m; and the total thickness of the thin-plate portion 12 and the piezoelectric/electrostrictive element 14 is preferably 7 .mu.m to 500 .mu.m. The thickness of each of the electrodes 14a1 to 14a5 is preferably 0.1 .mu.m to 50 .mu.m; and the thickness of each of the piezoelectric/electrostrictive layers 14b1 to 14b5 is preferably 3 .mu.m to 300 .mu.m.

Preferably, as in the case of the holding portions 13 and the stationary portion 11, a ceramic material is employed for forming the thin-plate portions 12. Among ceramic materials, a material containing, as a primary component, zirconia (in particular, stabilized zirconia or partially stabilized zirconia) is more preferred, since such a material exhibits, even when having a small thickness, high mechanical strength and high toughness, and it has low reactivity with the electrode material of the electrodes 14a1 and the piezoelectric/electrostrictive layers 14b1, which constitute the piezoelectric/electrostrictive element 14.

The thin-plate portions 12 can also be formed from a metallic material that has flexibility and allows bending deformation. Among preferred metallic materials for the thin-plate portions 12, examples of ferrous materials include stainless steels and spring steels, and examples of nonferrous materials include beryllium copper, phosphor bronze, nickel, and nickel-iron alloys.

Preferably, stabilized zirconia or partially stabilized zirconia to be employed in the piezoelectric/electrostrictive device 10 is stabilized or partially stabilized in the following manner. At least one compound, or two or more compounds selected from among yttrium oxide, ytterbium oxide, cerium oxide, calcium oxide, and magnesium oxide are added to zirconia to thereby stabilize or partially stabilize the zirconia.

Each of the compounds is added in the following amount: in the case of yttrium oxide or ytterbium oxide, 1 to 30 mol %, preferably 1.5 to 10 mol %; in the case of cerium oxide, 6 to 50 mol %, preferably 8 to 20 mol %; and in the case of calcium oxide or magnesium oxide, 5 to 40 mol %, preferably 5 to 20 mol %. Particularly, employment of yttrium oxide as a stabilizer is preferred. In this case, preferably, yttrium oxide is added in an amount of 1.5 to 10 mol % (more preferably, 2 to 4 mol % when mechanical strength is regarded as particularly important, or 5 to 7 mol % when endurance reliability is regarded as particularly important).

Alumina, silica, a transition metal oxide, or the like can be added to zirconia as a sintering aid or the like in an amount of 0.05 to 20 wt %. In the case where the piezoelectric/electrostrictive elements 14 are formed through film formation and monolithic firing, addition of alumina, magnesia, a transition metal oxide, or the like is preferred.

In the case where at least one of the stationary portion 11, the thin-plate portion 12, and the holding portion 13 is formed from a ceramic material, in order to obtain a ceramic material having a high mechanical strength and stable crystal phase, the average crystal grain size of zirconia is preferably regulated to 0.05 to 3 .mu.m, more preferably 0.05 to 1 .mu.m. As described above, the thin-plate portions 12 may be formed from a ceramic material similar to (but different from) that employed to form the holding portions 13 and the stationary portion 11. However, preferably, the thin-plate portions 12 are formed from a material substantially identical to that of the holding portions 13 and the stationary portion 11 in view of enhancement of the reliability of joint portions, enhancement of the strength of the piezoelectric/electrostrictive device 10, and simplification of a procedure for manufacturing the piezoelectric/electrostrictive device 10.

A piezoelectric/electrostrictive device can employ a piezoelectric/electrostrictive element of a unimorph type, a bimorph type, or the like. However, the unimorph type, in which the thin-plate portions 12 and corresponding piezoelectric/electrostrictive elements are combined together, is advantageous in terms of stability of displacement quantity, a reduction in weight, and easy design for avoiding occurrence of opposite orientations between stress generated in the piezoelectric/electrostrictive element and strain associated with deformation of the piezoelectric/electrostrictive device. Therefore, the unimorph type is suitable for the piezoelectric/electrostrictive device 10.

When, as shown in FIG. 1, the piezoelectric/electrostrictive elements 14 are formed in such a manner that one end of each of the piezoelectric/electrostrictive elements 14 is located on the stationary portion 11 (or the corresponding holding portion 13), whereas the other end is located on the lateral surface of the corresponding thin-plate portion 12, the thin-plate portions 12 can be driven to a greater extent.

Preferably, the piezoelectric/electrostrictive layers 14b1 to 14b4 are formed from a piezoelectric ceramic material. Alternatively, the piezoelectric/electrostrictive layers 14b1 to 14b4 may be formed from an electrostrictive ceramic material, a ferroelectric ceramic material, or an antiferroelectric ceramic material. In the case where, in the piezoelectric/electrostrictive device 10, the linearity between the displacement quantity of the holding portions 13 and a drive voltage (or output voltage) is regarded as important, preferably, the piezoelectric/electrostrictive layers 14b1 to 14b4 are formed from a material having low strain hysteresis. Therefore, preferably, the piezoelectric/electrostrictive layers 14b1 to 14b4 are formed from a material having a coercive electric field of 10 kV/mm or less.

A specific material for the piezoelectric/electrostrictive layers 14b1 to 14b4 is a ceramic material containing, singly or in combination, lead zirconate, lead titanate, magnesium lead niobate, nickel lead niobate, zinc lead niobate, manganese lead niobate, antimony lead stannate, manganese lead tungstate, cobalt lead niobate, barium titanate, sodium bismuth titanate, potassium sodium niobate, strontium bismuth tantalate, and the like.

Particularly, a material containing, as a primary component, lead zirconate, lead titanate, or magnesium lead niobate, or a material containing, as a primary component, sodium bismuth titanate is preferred as a material for the piezoelectric/electrostrictive layers 14b1 to 14b4, from the viewpoints of high electromechanical coupling coefficient, high piezoelectric constant, low reactivity with the thin-plate (ceramic) portion 12 during sintering of the piezoelectric/electrostrictive layers 14b1 to 14b4, and attainment of consistent composition.

Furthermore, there can be employed, as a material for the piezoelectric/electrostrictive layers 14b1 to 14b4, a ceramic material containing an oxide of, for example, lanthanum, calcium, strontium, molybdenum, tungsten, barium, niobium, zinc, nickel, manganese, cerium, cadmium, chromium, cobalt, antimony, iron, yttrium, tantalum, lithium, bismuth, or tin. In this case, incorporation of lanthanum or strontium into lead zirconate, lead titanate, or magnesium lead niobate, which is a primary component, may yield in some cases such an advantage that coercive electric field and a piezoelectric characteristic become adjustable.

Notably, addition of a material prone to vitrify, such as silica, to a material for the piezoelectric/electrostrictive layers 14b1 to 14b4 is desirably avoided. This is because, silica or a similar material is prone to react with a piezoelectric/electrostrictive material during thermal treatment of the piezoelectric/electrostrictive layers 14b1 to 14b4; as a result, the composition of the piezoelectric/electrostrictive material varies with a resultant deterioration in the piezoelectric property.

Meanwhile, preferably, the electrodes 14a1 to 14a5 of the piezoelectric/electrostrictive elements 14 are formed from a metal that is solid at room temperature and has excellent electrical conductivity. Examples of the metal include aluminum, titanium, chromium, iron, cobalt, nickel, copper, zinc, niobium, molybdenum, ruthenium, palladium, rhodium, silver, tin, tantalum, tungsten, iridium, platinum, gold, lead, and an alloy of these metals. Furthermore, an electrode material can be a cermet material prepared by dispersing in any of the above metals a material identical to that of the piezoelectric/electrostrictive layers 14b1 to 14b4 or that of the thin-plate portions 12.

Selection of an electrode material for use in the piezoelectric/electrostrictive element 14 depends on a method of forming the piezoelectric/electrostrictive layers 14b1 to 14b4. For example, in the case where the electrode 14a1 is formed on the thin-plate portion 12, and then the piezoelectric/electrostrictive layer 14b1 is formed on the electrode 14a1 through firing, the electrode 14a1 must be formed of a high-melting-point metal, such as platinum, palladium, a platinum-palladium alloy, or a silver-palladium alloy, which remains intact even when exposed to a firing temperature of the piezoelectric/electrostrictive layer 14b1. This also applies to other electrodes (electrodes 14a2 to 14a4) whose formation is followed by firing of corresponding piezoelectric/electrostrictive layers.

In contrast, in the case of the outermost electrode 14a5 to be formed on the piezoelectric/electrostrictive layer 14b4, the formation of the electrode 14a5 is not followed by firing of a piezoelectric/electrostrictive layer. Thus, the electrode 14a5 can be formed from a material containing, as a primary component, a low-melting-point metal, such as aluminum, gold, or silver.

Since the laminar electrodes 14a1 to 14a5 possibly cause a reduction in displacement of the piezoelectric/electrostrictive element 14, each of the electrode layers is desirably thin. Particularly, the electrode 14a5, which is formed after the piezoelectric/electrostrictive layer 14b4 is fired, is formed preferably from an organic metal paste, which enables the formation of a dense, very thin film after firing. Examples of the paste include a gold resinate paste, a platinum resinate paste, and a silver resinate paste.

In the piezoelectric/electrostrictive device 10 of FIG. 1, the protrusions 12a for specifying the region where an adhesive is applied are provided. However, the protrusions 12a may be omitted as shown in FIG. 3. As a result, when an object is attached to the holding portions 13, an object of a size corresponding to the distance between the holding portions 13 and the thin-plate portions 12 can be held. In this case, regions where an adhesive is applied in order to hold the object substantially serve as the corresponding holding portions 13.

The aforementioned piezoelectric/electrostrictive device 10 can also be employed as an ultrasonic sensor, an acceleration sensor, an angular-velocity sensor, an impact sensor, a mass sensor, or a similar sensor. In application to such a sensor, the piezoelectric/electrostrictive device 10 is advantageous in that sensor sensitivity can be readily adjusted by appropriately regulating the size of an object to be held between the opposed holding portions 13 or between the opposed thin-plate portions 12.

Next will be described a method for manufacturing the aforementioned piezoelectric/electrostrictive device 10. Preferably, a substrate portion (which excludes the piezoelectric/electrostrictive elements 14; i.e., which includes the stationary portion 11, the thin-plate portions 12, and the holding portions 13) of the piezoelectric/electrostrictive device 10 is manufactured by a ceramic green sheet lamination process. Meanwhile, preferably, the piezoelectric/electrostrictive elements 14 are manufactured by a film formation process, which is adapted to form a thin film, a thick film, or a similar film.

A ceramic green sheet lamination process allows integral formation of members of the substrate portion of the piezoelectric/electrostrictive device 10. Thus, employment of a ceramic green sheet lamination process allows a joint portion between members to be almost free from a change in state with passage of time, thereby enhancing the reliability of joint portions and securing rigidity. In the case where the substrate portion is formed by laminating metallic plates, employment of a diffusion joining process allows a joint portion between members to be almost free from a change in state with passage of time, thereby securing the reliability of joint portions, and rigidity.

In the piezoelectric/electrostrictive device 10 of FIG. 1 according to the present embodiment, boundary portions (joint portions) between the thin-plate portions 12 and the stationary portion 11, and boundary portions (joint portions) between the thin-plate portions 12 and the corresponding holding portions 13 serve as fulcrum points for manifestation of displacement. Therefore, the reliability of the joint portions is an important factor that determines the characteristics of the piezoelectric/electrostrictive device 10.

A manufacturing method to be described below features high productivity and excellent formability and thus can yield the piezoelectric/electrostrictive devices 10 having a predetermined shape within a short period of time with good reproducibility.

In the following description, a laminate obtained by laminating a plurality of ceramic green sheets is defined as a ceramic green sheet laminate 22 (see FIG. 5); and a monolithic body obtained by firing the ceramic green sheet laminate 22 is defined as a ceramic laminate 23 (see FIG. 6).

The manufacturing method is embodied desirably as follows: a single sheet equivalent to a plurality of ceramic laminates of FIG. 6 arranged lengthwise and crosswise is prepared; a laminate corresponding to a plurality of laminates 24 (see FIG. 7), which are formed into the piezoelectric/electrostrictive elements 14, is formed continuously on the surfaces of the sheet in predetermined regions; and the sheet is cut, whereby a plurality of piezoelectric/electrostrictive devices 10 are manufactured in the same process. Furthermore, desirably, two or more piezoelectric/electrostrictive devices 10 are yielded in association with a single window (including Wd1 and the like shown in FIG. 4). In order to simplify description, the following description discusses a method for obtaining a single piezoelectric/electrostrictive device 10 from a ceramic laminate by cutting the ceramic laminate.

Firstly, a binder, a solvent, a dispersant, a plasticizer, and the like are mixed with ceramic powder of zirconia or the like, thereby preparing a slurry. The slurry is defoamed. By use of the defoamed slurry, a rectangular ceramic green sheet having a predetermined thickness is formed by a reverse roll coater process, a doctor blade process, or a similar process.

Subsequently, as shown in FIG. 4, if necessary, a plurality of ceramic green sheets 21a to 21f are formed from the above-prepared ceramic green sheet by blanking with a die, laser machining, or similar machining.

In the example of FIG. 4, rectangular windows Wd1 to Wd4 are formed in the ceramic green sheets 21b to 21e, respectively. The windows Wd1 and Wd4 have almost the same shape, and the windows Wd2 and Wd3 have almost the same shape. Each of the ceramic green sheets 21a and 21f includes a portion that is formed into the thin-plate portion 12. Notably, the number of ceramic green sheets is given merely as an example. In the illustrated example, the ceramic green sheets 21c and 21d may be replaced with a single green sheet having a predetermined thickness or with a plurality of ceramic green sheets to be laminated so as to attain the predetermined thickness or with a green sheet laminate having the predetermined thickness.

Thereafter, as shown in FIG. 5, the ceramic green sheets 21a to 21f are laminated and compression-bonded to thereby form the ceramic green sheet laminate 22. Subsequently, the ceramic green sheet laminate is fired to thereby form the ceramic laminate 23 shown in FIG. 6. No particular limitation is imposed on the number and order of compression-bonding operations for forming the ceramic green sheet laminate 22 (for monolithic lamination). In the case where there exists a portion to which pressure is not sufficiently transmitted by uniaxial application of pressure (application of pressure in a single direction), desirably, compression bonding is repeated a plurality of times, or impregnation with a pressure-transmitting substance is employed in compression bonding. Also, for example, the shape of the windows Wd1 to Wd4 and the number and thickness of ceramic green sheets can be appropriately determined in accordance with the structure and function of the piezoelectric/electrostrictive device 10 to be manufactured.

When the above compression bonding for monolithic lamination is performed under application of heat, a more reliable state of lamination is obtained. When a paste, a slurry, or the like that contains a predominant amount of a ceramic powder and a binder and serves as a bonding aid layer is applied to ceramic green sheets by means of coating or printing before the ceramic green sheets are compression-bonded, the state of bonding at the interface between the ceramic green sheets can be enhanced. In this case, preferably, the ceramic powder to be employed as a bonding aid has a composition identical to or similar to a ceramic material employed in the ceramic green sheets 21a to 21f in view of the reliability of bonding. Furthermore, in the case where the ceramic green sheets 21a and 21f are thin, the use of a plastic film (particularly, a polyethylene terephthalate film coated with a silicone-based parting agent) is preferred in handling the ceramic green sheets 21a and 21f. When the windows Wd1 and Wd4 and the like are to be formed in relatively thin sheets, such as the ceramic green sheets 21b and 21e, each of these sheets may be attached to the aforementioned plastic film before a process for forming the windows Wd1 and Wd4 and the like is performed.

Subsequently, as shown in FIG. 7, the piezoelectric/electrostrictive laminates 24 are formed on the corresponding opposite sides of the ceramic laminate 23; i.e., on the corresponding surfaces of the fired ceramic green sheets 21a and 21f. Examples of methods for forming the piezoelectric/electrostrictive laminates 24 include thick-film formation processes, such as a screen printing process, a dipping process, a coating process, and an electrophoresis process; and thin-film formation processes, such as an ion beam process, a sputtering process, a vacuum deposition process, an ion plating process, a chemical vapor deposition (CVD) process, and a plating process.

Employment of such a film formation process in formation of the piezoelectric/electrostrictive laminates 24 allows the piezoelectric/electrostrictive laminates 24 and the thin-plate portions 12 to be monolithically bonded (disposed) without use of adhesive, thereby securing reliability and reproducibility and facilitating integration.

In this case, more preferably, a thick-film formation process is employed for forming the piezoelectric/electrostrictive laminates 24. A thick-film formation process allows, in film formation, the use of a paste, a slurry, a suspension, an emulsion, a sol, or the like containing, as a primary component, piezoelectric ceramic particles or powder having an average particle size of 0.01 to 5 .mu.m, preferably 0.05 to 3 .mu.m. The piezoelectric/electrostrictive laminates 24 obtained by firing the thus-formed films exhibit a good piezoelectric/electrostrictive characteristic.

An electrophoresis process has such an advantage that a film can be formed with high density and high shape accuracy. A screen printing process can simultaneously perform control of film thickness and pattern formation and thus can simplify a manufacturing process.

An example method for forming the ceramic laminate 23 and the piezoelectric/electrostrictive laminates 24 will be described in detail. Firstly, the ceramic green sheet laminate 22 is monolithically fired at a temperature of 1,200 to 1,600.degree. C., thereby yielding the ceramic laminate 23 shown in FIG. 6. Thereafter, as shown in FIG. 2, the electrodes 14a1 are printed on the corresponding opposite sides of the ceramic laminate 23 at a predetermined position, followed by firing. Subsequently, the piezoelectric/electrostrictive layers 14b1 are printed and fired. The electrodes 14a2 are printed on the corresponding piezoelectric/electrostrictive layers 14b1, followed by firing. Such an operation is repeated a predetermined number of times to thereby form the piezoelectric/electrostrictive laminates 24. Thereafter, a terminal (not illustrated) for electrically connecting the electrodes 14a1, 14a3, and 14a5 to a drive circuit, and a terminal (not illustrated) for electrically connecting the electrodes 14a2 and 14a4 to the drive circuit are printed and fired.

Alternatively, the piezoelectric/electrostrictive laminates 24 may be formed as follows. The bottom electrode 14a1 is printed and fired. Subsequently, the piezoelectric/electrostrictive layer 14b1 and the electrode 14a2 are printed and are then simultaneously fired. Thereafter, in a manner similar to that described above, a process in which a single piezoelectric/electrostrictive layer and a single electrode are printed and then simultaneously fired is repeated a predetermined number of times.

In this case, for example, the electrodes 14a1, 14a2, 14a3, and 14a4 are formed from a material containing, as a primary component, platinum (Pt); the piezoelectric/electrostrictive layers 14b1 to 14b4 are formed from a material containing, as a primary component, lead zirconate titanate (PZT); the electrode 14a5 is formed from gold (Au); and the terminals are formed from silver (Ag). In this manner, materials are selected in such a manner that their firing temperature lowers in the ascending order of lamination. As a result, at a certain firing stage, a material(s) that has been fired is free from re-sintering, thereby avoiding occurrence of a problem, such as the exfoliation or cohesion of an electrode material.

The selection of appropriate materials allows the members of the piezoelectric/electrostrictive laminates 24 and the terminals to be sequentially printed and then monolithically fired in a single firing operation. Also, the piezoelectric/electrostrictive laminate 24 may be formed as follows: the firing temperature for the outermost piezoelectric/electrostrictive layer 14b4 is regulated to be higher than that for the piezoelectric/electrostrictive layers 14b1 to 14b3, so as to finally bring the piezoelectric/electrostrictive layers 14b1 to 14b4 into the same sintered state.

The members of the piezoelectric/electrostrictive laminates 24 and the terminals may be formed by a thin-film formation process, such as a sputtering process or a vapor deposition process. In this case, thermal treatment is not necessarily required.

The following simultaneous firing process may be employed. The piezoelectric/electrostrictive laminates 24 are formed on the corresponding opposite sides of the ceramic green sheet laminate 22; i.e., on the corresponding surfaces of the ceramic green sheets 21a and 21f. Subsequently, the ceramic green sheet laminate 22 and the piezoelectric/electrostrictive laminates 24 are simultaneously fired.

In an example method for simultaneously firing the piezoelectric/electrostrictive laminates 24 and the ceramic green sheet laminate 22, precursors of the piezoelectric/electrostrictive laminates 24 are formed by a tape formation process employing a slurry raw material, or a similar process; the precursors of the piezoelectric/electrostrictive laminates 24 are laminated on the corresponding opposite sides of the ceramic green sheet laminate 22 by thermo-compression bonding or a similar technique; and subsequently the precursors and the ceramic green sheet laminate 22 are simultaneously fired. However, in this method, the electrodes 14a1 must be formed in advance on the corresponding opposite sides of the ceramic green sheet laminate 22 and/or on the corresponding piezoelectric/electrostrictive laminates 24 by means of any film formation process described above.

In another method, the electrodes 14a1 to 14a5 and the piezoelectric/electrostrictive layers 14b1 to 14b4, which are component layers of the piezoelectric/electrostrictive laminates 24, are screen-printed at least on those portions of the ceramic green sheet laminate 22 which are finally formed into the corresponding thin-plate portions 12; and the component layers and the ceramic green sheet laminate 22 are simultaneously fired.

The firing temperature for a component layer of the piezoelectric/electrostrictive laminates 24 is appropriately determined on the basis of the material of the component layer, but is generally 500 to 1,500.degree. C. The preferred firing temperature for the piezoelectric/electrostrictive layers 14b1 to 14b4 is 1,000 to 1,400.degree. C. In this case, preferably, in order to control the composition of the piezoelectric/electrostrictive layers 14b1 to 14b4, sintering is performed in such a state that evaporation of the material of the piezoelectric/electrostrictive layers 14b1 to 14b4 is controlled (for example, in the presence of an evaporation source). In the case where the piezoelectric/electrostrictive layers 14b1 to 14b4 and the ceramic green sheet laminate 22 are simultaneously fired, their firing conditions must be compatible with each other. The piezoelectric/electrostrictive laminates 24 are not necessarily formed on the corresponding opposite sides of the ceramic laminate 23 or the ceramic green sheet laminate 22, but may be formed only on a single side of the ceramic laminate 23 or the ceramic green sheet laminate 22.

Subsequently, as stated above, unnecessary parts are cut off from the ceramic laminate 23 on which piezoelectric/electrostrictive laminates 24 are formed ("a piece comprising a ceramic laminate 23 and piezoelectric/electrostrictive laminates 24" composing a piezoelectric/electrostrictive device 10 afterward is hereunder referred to as "a work piece" occasionally). That is, the work piece is cut along the cutting lines (broken lines) C1 to C4 shown in FIG. 8. As the cutting means, machining or the like such as wire sawing, dicing, or the like, can be adopted.

In the cutting, the cutting of the work piece along the cutting lines C3 and C4 shown in FIG. 8 includes the cutting of the piezoelectric/electrostrictive laminates 24 comprising brittle piezoelectric/electrostrictive layers having a relatively low strength and a metal having glutinous ductility and hence it is desirable not to adopt dicing which imposes heavy processing load on the work piece at the cutting but to adopt other processing which imposes light processing load on the work piece. In particular, the wire sawing which is suitable for simultaneous cutting and forming of a plurality of piezoelectric/electrostrictive devices 10 and imposes low processing load is appropriate for such cutting.

Further, not in the case of cutting a composite comprising pluralities of ceramics, electrodes, and piezoelectric/electrostrictive layers having mechanical properties (physical properties related to cutting) different from each other like cutting along the cutting lines C3 and C4 but in the case of cutting the portions comprising ceramics having mechanical properties identical or similar to each other like cutting along the cutting lines C1 and C2, another processing method may be used besides wire sawing. For example, it is preferable to adopt dicing in the case of cutting along the cutting lines C1 and C2.

By cutting a work piece along the cutting lines C1 to C4 shown in FIG. 8 as stated above, a work piece which does not yet have protrusions 12a to be formed thereon and is not yet subjected to the specific processing that will be described later but corresponds to a piezoelectric/electrostrictive device 10 shown in FIG. 1 is obtained.

Subsequently, protrusions that compose protrusions 12a afterward (namely, protrusions 12a before sintered) are formed onto such a work piece at prescribed positions of the work piece respectively with the slurry identical to the slurry used in the forming of the aforementioned ceramic green sheets 21a to 21f. As a method for forming such protrusions too, in the same way as the aforementioned method for forming piezoelectric/electrostrictive laminates 24, thick-film forming processes such as a screen printing process, a dipping process, a coating process, and an electrophoresis process, and thin-film forming processes such as an ion beam process, a sputtering process, a vacuum deposition process, an ion plating process, a chemical vapor deposition (CVD) process, and a plating process can be used.

Subsequently, the work piece on which the protrusions are formed is sintered. Thereby the protrusions 12a sintered integrally with the material identical to the material of the thin-plate portions 12 are formed. As a result, a work piece which is not yet subjected to the specific processing and corresponds to the piezoelectric/electrostrictive device 10 shown in FIG. 1 (hereunder referred to as "pre-specific processing piezoelectric/electrostrictive device") is obtained.

Then finally, the specific processing is applied to two lateral end surfaces of the pre-specific processing piezoelectric/electrostrictive device (namely, cut planes along the aforementioned cutting lines C3 and C4) corresponding to two lateral end surfaces of the piezoelectric/electrostrictive device 10. Thereby the piezoelectric/electrostrictive device 10 shown in FIG. 1 is produced.

Such specific processing is hereunder explained in detail. The purpose of the specific processing is, when the piezoelectric/ele