WO2018199170A1 - Vibrator, method for manufacturing the same, vibration wave driving device, vibration wave motor, optical device, and electronic device - Google Patents

Vibrator, method for manufacturing the same, vibration wave driving device, vibration wave motor, optical device, and electronic device Download PDF

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Publication number
WO2018199170A1
WO2018199170A1 PCT/JP2018/016825 JP2018016825W WO2018199170A1 WO 2018199170 A1 WO2018199170 A1 WO 2018199170A1 JP 2018016825 W JP2018016825 W JP 2018016825W WO 2018199170 A1 WO2018199170 A1 WO 2018199170A1
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WO
WIPO (PCT)
Prior art keywords
piezoelectric element
vibration
vibrator
vibration plate
resin
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PCT/JP2018/016825
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English (en)
French (fr)
Inventor
Jumpei Hayashi
Hidenori Tanaka
Takayuki Watanabe
Shinya Koyama
Tatsuo Furuta
Makoto Kubota
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Canon Kabushiki Kaisha
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Publication of WO2018199170A1 publication Critical patent/WO2018199170A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/02—Mountings, adjusting means, or light-tight connections, for optical elements for lenses
    • G02B7/04—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification
    • G02B7/08—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification adapted to co-operate with a remote control mechanism
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
    • H02N2/00—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction
    • H02N2/0005—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing non-specific motion; Details common to machines covered by H02N2/02 - H02N2/16
    • H02N2/001—Driving devices, e.g. vibrators
    • H02N2/0015—Driving devices, e.g. vibrators using only bending modes
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
    • H02N2/00—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction
    • H02N2/0005—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing non-specific motion; Details common to machines covered by H02N2/02 - H02N2/16
    • H02N2/005—Mechanical details, e.g. housings
    • H02N2/0055—Supports for driving or driven bodies; Means for pressing driving body against driven body
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
    • H02N2/00—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction
    • H02N2/02—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing linear motion, e.g. actuators; Linear positioners ; Linear motors
    • H02N2/026—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing linear motion, e.g. actuators; Linear positioners ; Linear motors by pressing one or more vibrators against the driven body

Definitions

  • the present invention relates to a vibrator, a method for manufacturing the vibrator, and devices including the vibrator, namely, a vibration wave driving device, a vibration wave motor, an optical device, and an electronic device.
  • PTL 1 discloses a vibration-type drive device (ultrasonic motor) including a small vibrator that is driven by combined vibration using a combination of two different out-of-plane vibration modes.
  • a vibrator typically includes a piezoelectric element and a vibration plate that adheres to the piezoelectric element with an elastic resin layer interposed therebetween.
  • a reduction in the size of a vibrator results in an increase in the ratio of the area occupied by ends of the piezoelectric element to the area of a bonding region where the piezoelectric element and the vibration plate are bonded to each other.
  • the vibrator disclosed in PTL 1 which is driven by combined vibration using a combination of two different out-of-plane vibration modes, due to the driving principle, antinodal lines of vibration in the two out-of-plane vibration modes are located at the ends of the piezoelectric element. For these reasons, if a vibration wave motor including the vibrator is driven continuously, peeling is likely to occur starting from the ends of the piezoelectric element.
  • piezoelectric elements using lead-free piezoelectric ceramics which tend to be stiffer and subjected to larger temperature changes than lead-based materials, are more likely to experience the peeling phenomenon described above because the difference in stiffness between the piezoelectric elements and vibration plates is likely to vary.
  • the present invention provides a vibrator with reduced occurrence of peeling between a piezoelectric element and a vibration plate thereof even when the vibrator includes a lead-free piezoelectric ceramic.
  • a vibrator includes a piezoelectric element and a vibration plate.
  • the piezoelectric element includes a piezoelectric ceramic formed into a substantially rectangular parallelepiped shape, and electrodes. A portion of one or more side surfaces of the piezoelectric element and a portion of the vibration plate are covered by resin.
  • a vibrator that is environmentally safe with reduced occurrence of peeling between a piezoelectric element and a vibration plate thereof, and a method for manufacturing the vibrator. It may also be possible to provide devices including the vibrator, namely, a vibration wave driving device, a vibration wave motor, an optical device, and an electronic device.
  • Fig. 1 is a schematic diagram illustrating a piezoelectric element according to an embodiment of the present invention.
  • Fig. 2A is a schematic diagram illustrating an example of a vibrator according to the embodiment of the present invention.
  • Fig. 2B is a schematic diagram illustrating an example of the vibrator according to the embodiment of the present invention.
  • Fig. 3A is a schematic diagram illustrating an example of the vibrator according to the embodiment of the present invention.
  • Fig. 3B is a schematic diagram illustrating an example of the vibrator according to the embodiment of the present invention.
  • Fig. 3C is a schematic diagram illustrating an example of the vibrator according to the embodiment of the present invention.
  • Fig. 3D is a schematic diagram illustrating an example of the vibrator according to the embodiment of the present invention.
  • Fig. 3E is a schematic diagram illustrating an example of the vibrator according to the embodiment of the present invention.
  • Fig. 3F is a schematic diagram illustrating an example of the vibrator according to the embodiment of the present invention.
  • Fig. 4A is a schematic diagram illustrating an example of the vibrator according to the embodiment of the present invention.
  • Fig. 4B is a schematic diagram illustrating an example of the vibrator according to the embodiment of the present invention.
  • Fig. 5A is a schematic diagram illustrating an example of a vibrator according to a comparative example.
  • Fig. 5B is a schematic diagram illustrating an example of the vibrator according to the comparative example.
  • Fig. 5A is a schematic diagram illustrating an example of a vibrator according to a comparative example.
  • FIG. 6A is a schematic diagram illustrating an example of two out-of-plane vibration modes of the vibrator according to the embodiment of the present invention.
  • Fig. 6B is a schematic diagram illustrating an example of the two out-of-plane vibration modes of the vibrator according to the embodiment of the present invention.
  • Fig. 7 is a schematic diagram illustrating an example of the vibrator according to the embodiment of the present invention.
  • Fig. 8 is a schematic diagram illustrating a vibration wave driving device according to an embodiment of the present invention.
  • Fig. 9 is a schematic diagram illustrating a vibration wave motor according to an embodiment of the present invention.
  • Fig. 10 is a schematic diagram illustrating an optical device according to an embodiment of the present invention.
  • a vibrator includes a piezoelectric element and a vibration plate.
  • the piezoelectric element includes a lead-free piezoelectric ceramic formed into a substantially rectangular parallelepiped shape, and electrodes. A portion of one or more side surfaces of the piezoelectric element and a portion of the vibration plate are covered by resin.
  • An embodiment of the present invention can provide a vibrator that is environmentally safe with reduced occurrence of peeling between a piezoelectric element and a vibration plate thereof.
  • the vibrator according to the embodiment of the present invention includes a piezoelectric element and a vibration plate that adheres to the piezoelectric element with a resin layer interposed therebetween.
  • the vibrator according to the embodiment of the present invention can generate a bending vibration traveling wave in an out-of-plane direction (hereinafter referred to as out-of-plane vibration).
  • Fig. 1 is a schematic diagram illustrating a piezoelectric element included in a vibrator according to an embodiment of the present invention.
  • a piezoelectric element 101 includes a single-piece lead-free piezoelectric ceramic 1 formed into a substantially rectangular parallelepiped shape, and a plurality of electrodes (a first electrode 2 and second electrodes 3) disposed on the piezoelectric ceramic 1.
  • the piezoelectric ceramic 1 is a bulk (sintered body) having a substantially uniform composition, which is obtained by firing a raw material powder.
  • the piezoelectric ceramic 1 is a ceramic that exhibits a piezoelectric constant d 31 greater than or equal to 10 pm/V in absolute value or a piezoelectric constant d 33 greater than or equal to 30 pC/N at 20°C when subjected to polarization processing.
  • single-piece refers to a seamless body having a substantially uniform composition.
  • substantially rectangular parallelepiped shape is used to include an exactly rectangular parallelepiped shape and any other rectangular parallelepiped-like shape such as a rectangular parallelepiped shape with chamfered sides.
  • the piezoelectric constant of the piezoelectric ceramic 1 can be determined by computation using the density and resonant and antiresonant frequencies of the piezoelectric ceramic 1 in accordance with the Japan Electronics and Information Technology Industries Association (JEITA) standard (EM-4501). In the following, this method is referred to as a resonance-antiresonance method.
  • JEITA Japan Electronics and Information Technology Industries Association
  • the density of the piezoelectric ceramic 1 can be measured by using, for example, Archimedes method.
  • the resonant frequency and the antiresonant frequency can be measured with an impedance analyzer.
  • a piezoelectric constant measurement device that uses the Berlincourt method as a measurement principle may be used to measure the piezoelectric constant of the piezoelectric ceramic 1.
  • the piezoelectric ceramic 1 preferably contains a perovskite metal oxide. This is because the piezoelectric ceramic 1, which contains a perovskite metal oxide, can have a higher piezoelectric constant than any other metal oxide having a crystal structure.
  • the plurality of electrodes are each made of a conductive material having a thickness of about 5 nm to 10 ⁇ m. This is because the plurality of electrodes serve to apply voltages to the piezoelectric ceramic 1.
  • the material of the plurality of electrodes is not particularly limited, and examples of the material include metals such as Ti, Pt, Au, Ni, Pd, Ag, and Cu, and compounds thereof.
  • a silver paste is preferably used since it has low cost and sufficient conductivity. When a silver paste is used, the plurality of electrodes can be produced by applying the silver paste to the piezoelectric ceramic 1 in a desired pattern and drying or burning the piezoelectric ceramic 1.
  • the first electrode 2 can be used as a common ground electrode, for example, and the second electrodes 3 can be used as electrodes for applying drive voltages, for example.
  • FIGs. 2A and 2B are schematic diagrams illustrating the vibrator according to the embodiment of the present invention.
  • a resin layer 4 extends from a bonding region where the piezoelectric element 101 and a vibration plate 5 are bonded to each other and covers at least a portion of one or more side surfaces of the piezoelectric element 101, which are approximately perpendicular to a surface of the piezoelectric element 101 that adheres to the vibration plate 5. This configuration can prevent the occurrence of peeling between the piezoelectric element 101 and the vibration plate 5.
  • the bonding region represents a region 41 illustrated in Fig. 2B where the surface of the piezoelectric element 101 that adheres to the vibration plate 5 (this surface is hereinafter referred to as the adhering surface) is in contact with the vibration plate 5.
  • the area of the adhering surface represents the area of the bonding region. If the vibration plate 5 has a hole such as a through-hole, the area of the bonding region is determined by subtracting the area of the hole from the area of the adhering surface.
  • resin may be disposed in a region where the vibration plate 5 and the piezoelectric element 101 face each other, and an area coverage ratio that is a ratio of an area of the resin disposed in the region to an area of the region is preferably greater than or equal to 60%.
  • the area coverage ratio can be measured by using, for example, a photographic image obtained by an ultrasonic imaging device. If the area coverage ratio is less than 60%, the adherence of the piezoelectric element 101 to the vibration plate 5 may be insufficient, which can result in it being more likely that peeling will occur between the piezoelectric element 101 and the vibration plate 5.
  • Figs. 3A to 3F are schematic diagrams illustrating the vibrator according to the embodiment of the present invention, as viewed from a different angle from that illustrated in Figs. 2A and 2B.
  • Fig. 3A illustrates a vibrator 1011 as viewed from a surface of the piezoelectric element 101 having the second electrodes 3.
  • the resin layer 4 As illustrated in Fig. 3A, at least a portion of one or more side surfaces of the piezoelectric element 101 is covered by the resin layer 4, which can result in it being less likely that the vibrator 1011 will have peeling between the piezoelectric element 101 and the vibration plate 5.
  • side surfaces of the piezoelectric element approximately perpendicular to the adhering surface refers to four surfaces other than the adhering surface and a surface opposite the adhering surface, that is, four surfaces of the piezoelectric element other than the surface having the first electrode 2 and the surface having the second electrodes 3.
  • Figs. 3B, 3C, and 3D also illustrate the vibrator 1011 as viewed from the surface of the piezoelectric element 101 having the second electrodes 3.
  • the resin layer 4 preferably covers a pair of opposing side surfaces of the piezoelectric element 101. Since the piezoelectric element 101 included in the vibrator 1011 has a single-piece substantially rectangular parallelepiped shape, symmetrical vibration (vibration having line symmetry) is generated in the vibrator 1011 in the long-side and short-side directions of the piezoelectric element 101 in accordance with the expansion and contraction of the piezoelectric element 101.
  • the resin layer 4 which provides efficient vibration that is not affected by vibration other than desired vibration (i.e., unwanted vibration) without impairing symmetry of vibration. As a result, it can be less likely that peeling will occur between the piezoelectric element 101 and the vibration plate 5. More preferably, as illustrated in Fig. 3D, the resin layer 4 covers all the side surfaces of the piezoelectric element 101.
  • Figs. 3E and 3F also illustrate the vibrator 1011 as viewed from the surface of the piezoelectric element 101 having the second electrodes 3.
  • the resin layer 4 may cover some of the side surfaces of the piezoelectric element 101 in the manner illustrated in Fig. 3F or may cover three side surfaces of the piezoelectric element 101 in the manner illustrated in Fig. 3E.
  • the ratio of the maximum height of resin disposed in a portion of a side surface of the piezoelectric element 101 to the height of the side surface of the piezoelectric element 101 is preferably greater than or equal to 5% and less than or equal to 70%. Setting the ratio of the maximum height of resin to the height of the piezoelectric element 101 to be within the range described above can result in it being less likely that peeling will occur between the piezoelectric element 101 and the vibration plate 5. The ratio of the maximum height of resin to the height of the piezoelectric element 101 will be described with reference to Figs. 4A and 4B. Fig.
  • FIG. 4A is a schematic sectional view of the vibrator according to the embodiment of the present invention, as viewed from the long-side side of the adhering surface of the piezoelectric element 101.
  • the resin layer 4 extends on the short-side side of the adhering surface of the piezoelectric element 101.
  • Fig. 4B is a schematic diagram illustrating the vibrator according to the embodiment of the present invention, as viewed from the long-side side of the adhering surface of the piezoelectric element 101.
  • the resin layer 4 extends on the long-side side of the adhering surface of the piezoelectric element 101.
  • the ratio of the maximum height of resin to the height of the piezoelectric element 101 is defined as the ratio of a maximum height B of the resin layer 4 to a length A of a side surface of the piezoelectric element 101 in a height direction of the piezoelectric element 101.
  • a ratio greater than 70% may hinder the vibration of the vibrator 1011.
  • Figs. 5A and 5B are schematic sectional views of a vibrator according to a comparative example, which is not included in the present invention, as viewed from the long-side side of the adhering surface of the piezoelectric element 101, and illustrate a ratio less than 5%, by way of example. In an example illustrated in Fig.
  • the piezoelectric ceramic 1, which has been subjected to a so-called chamfering process is illustrated.
  • the resin layer 4 covers none of the side surfaces of the piezoelectric element 101.
  • a ratio less than 5% may cause insufficient adherence of the piezoelectric element 101 to the vibration plate 5, which can result in it being more likely that peeling will occur between the piezoelectric element 101 and the vibration plate 5.
  • the ratio of the maximum height of resin to the height of the piezoelectric element 101 can be measured by using, for example, a photographic image obtained with an optical microscope.
  • resin disposed in a region where the vibration plate 5 and the piezoelectric element 101 face each other preferably has a maximum thickness of greater than or equal to 0.5 ⁇ m and less than or equal to 10 ⁇ m. Setting the maximum thickness to be within the range described above can result in a sufficient mechanical strength of the resin layer 4.
  • vibration generated from the piezoelectric element 101 can be efficiently transmitted to the vibration plate 5.
  • the maximum thickness can be determined by measuring a cross section of the vibrator 1011 by using a photographic image obtained with, for example, a scanning electron microscope (hereinafter referred to as an SEM). If the maximum thickness is greater than 10 ⁇ m, vibration generated from the piezoelectric element 101 may not sufficiently be transmitted to the vibration plate 5. If the maximum thickness is less than 0.5 ⁇ m, in contrast, the mechanical strength of the resin layer 4 may be insufficient, which can result in it being more likely that peeling will occur between the piezoelectric element 101 and the vibration plate 5.
  • the resin layer 4 is preferably disposed only on a flat surface of the vibration plate 5 that faces the piezoelectric element 101. This configuration enables vibration generated in accordance with the expansion and contraction of the piezoelectric element 101 to be efficiently transmitted to the vibration plate 5. If the resin layer 4 is located out of the plane of the vibration plate 5, the vibration generated in accordance with the expansion and contraction of the piezoelectric element 101 may not be sufficiently transmitted to the vibration plate 5.
  • the resin layer 4 preferably includes epoxy-based resin.
  • An epoxy-based resin has higher water resistance and heat resistance than any other resin.
  • the thickness of the piezoelectric ceramic 1 in a direction extending along the side surfaces of the piezoelectric element 101 is preferably greater than or equal to 0.28 mm and less than or equal to 2.0 mm. Setting the thickness to be within the range described above can result in a sufficient mechanical strength of the piezoelectric ceramic 1 and can provide efficient transmission of vibration generated from the piezoelectric element 101 to the vibration plate 5. If the thickness is greater than 2.0 mm, the required voltage for causing the piezoelectric element 101 to vibrate may be increased. If the thickness is less than 0.28 mm, in contrast, the mechanical strength of the piezoelectric ceramic 1 may be insufficient.
  • the vibration plate 5 generates two nodal lines of a first vibration mode (vibration mode A) such that the two nodal lines do not intersect each other and three nodal lines of a second vibration mode (vibration mode B) such that the three nodal lines do not intersect each other, and the two nodal lines of the first vibration mode intersect the three nodal lines of the second vibration mode.
  • the resin layer 4 preferably covers a portion where at least either antinodal lines of the first vibration mode or antinodal lines of the second vibration mode are generated.
  • Figs. 6A and 6B are schematic diagrams illustrating out-of-plane vibration modes of the vibrator according to the embodiment of the present invention.
  • the vibration plate 5 has projection portions 51.
  • the projection portions 51 allow vibration generated by the vibrator 1011 to be efficiently transmitted to a contact body (e.g., a driven body described below).
  • the out-of-plane vibration mode illustrated in Fig. 6A is one of the two out-of-plane vibration modes (this out-of-plane vibration mode is hereinafter referred to as mode A).
  • the mode A is the first-order out-of-plane vibration mode in the short-side direction (arrow Y direction) of the substantially rectangular parallelepiped (rectangular) vibrator 1011 and has two nodal lines substantially parallel to the long-side direction (arrow X direction) of the vibrator 1011. The two nodal lines do not intersect each other.
  • the vibration plate 5 includes a plate portion and a support portion, and the plate portion and the support portion are integrated into a single unit.
  • Fig. 7 is a schematic diagram illustrating the vibrator according to the embodiment of the present invention.
  • the vibrator includes support portions 6.
  • the support portions 6, which are located out of the plane of the vibration plate 5, are connected to the vibration plate 5 and are made of the same material as that of the vibration plate 5.
  • This configuration allows the vibrator to be applied to a piezoelectric device such as a vibration wave motor described below without hindering vibration generated from the vibrator.
  • each of the support portions 6 has a hole into which a fixing portion fits, thereby providing a piezoelectric device with diverse structural designs.
  • the piezoelectric ceramic 1 preferably has a lead content less than 1000 ppm. That is, the piezoelectric ceramic 1 is preferably a lead-free piezoelectric ceramic. Most existing piezoelectric ceramics contain lead zirconate titanate (PZT) as a main component. Thus, it has been noted that, for example, if a piezoelectric element including such a piezoelectric ceramic is disposed of and subjected to acid rain or left exposed to severe environmental conditions, the lead component in the piezoelectric ceramic can be absorbed and precipitated in the soil and can disrupt an ecosystem's nature balance.
  • PZT lead zirconate titanate
  • the lead content of the piezoelectric ceramic can be measured by using the weight of lead relative to the total weight of the piezoelectric ceramic, which is determined by using X-ray fluorescence (XRF) analysis or inductively-coupled plasma (ICP) emission spectroscopic analysis, for example.
  • XRF X-ray fluorescence
  • ICP inductively-coupled plasma
  • the piezoelectric ceramic 1 preferably includes barium titanate or a substitute therefor in terms of high piezoelectric constant and comparatively easy manufacturing.
  • barium titanate or a substitute therefor include compositions such as barium titanate (BaTiO 3 ), barium calcium titanate ((Ba, Ca)TiO 3 ), barium zirconate titanate (Ba(Ti, Zr)O 3 ), barium calcium zirconate titanate ((Ba, Ca)(Ti, Zr)O 3 ), sodium niobate-barium titanate (NaNbO 3 -BaTiO 3 ), bismuth sodium titanate-barium titanate ((Bi, Na)TiO 3 -BaTiO 3 ), and bismuth potassium titanate-barium titanate ((Bi, K)TiO 3 -BaTiO 3 ), and materials containing these compositions as main components.
  • barium calcium zirconate titanate ((Ba, Ca)(Ti, Zr)O 3 ) or sodium niobate-barium titanate (NaNbO 3 -BaTiO 3 ) is preferably contained as a main component, in terms of achievement of both the piezoelectric constant and mechanical quality factor of the piezoelectric ceramic 1.
  • the piezoelectric ceramic 1 preferably contains manganese or bismuth as an element other than a main component.
  • a piezoelectric element included in the vibrator is obtained by providing a single-piece piezoelectric ceramic formed into a substantially rectangular parallelepiped shape with a plurality of electrodes.
  • the single-piece piezoelectric ceramic formed into a substantially rectangular parallelepiped shape is obtained by, for example, firing a raw material powder having a desired metal element and processing the resulting sintered body into a desired shape.
  • the plurality of electrodes can be disposed on the single-piece piezoelectric ceramic formed into a substantially rectangular parallelepiped shape by, for example, sputtering or applying a metal paste and drying or burning the piezoelectric ceramic.
  • the piezoelectric element needs to be subjected to polarization processing to exhibit piezoelectricity.
  • the polarization processing may be performed before or after a step of causing the piezoelectric element to adhere to the vibration plate described below. Note that when the polarization processing is performed before the adhering step, the subsequent steps need to be performed at a temperature less than or equal to the Curie temperature of the piezoelectric ceramic. The reason for this is to avoid depolarization of the piezoelectric ceramic to prevent piezoelectricity from being lost.
  • the piezoelectric element is made to adhere to the vibration plate.
  • a resin precursor having flowability is applied to a bonding surface of the piezoelectric element or the vibrator.
  • the term "flowability", as used herein, refers to the unstable, flowing ability.
  • the resin precursor is a resin before being cured, which indicates a liquid adhesive.
  • the adhesive may be a so-called one- or two-part adhesive.
  • the resin precursor may be applied to either the bonding surface of the piezoelectric element or the bonding surface of the vibrator.
  • the resin precursor is cured.
  • the piezoelectric element and the vibration plate are brought into pressure contact with each other with the resin-precursor-applied surface interposed therebetween. If a sufficient amount of the resin precursor is applied, pressure contact between the piezoelectric element and the vibration plate enables the resin precursor to protrude from the adhering surface toward at least a portion of the side surfaces of the piezoelectric element approximately perpendicular to the adhering surface. If an insufficient amount of the resin precursor is applied, the resin precursor does not protrude toward the side surfaces, which is not desirable.
  • Examples of a method for allowing the resin precursor to protrude toward a desired side surface include inclining the resin-precursor-applied surface in a desired direction from the horizontal direction, and disposing the piezoelectric element at an end of the vibration plate to prevent the resin precursor from protruding toward the end of the vibration plate.
  • Other examples include making the vibration plate water-repellent to prevent the resin precursor from protruding toward a specific surface, and removing a protrusion of the resin precursor. In the pressure contact process, a certain amount of pressure such that prevents the piezoelectric element from moving relative to the vibration plate and that ensures that the piezoelectric element is not cracked needs to be applied.
  • the vibrator is heated with the piezoelectric element and the vibration plate being brought into pressure contact, thereby reducing the curing time.
  • the heating temperature needs to be determined taking into account the Curie temperature of the piezoelectric ceramic.
  • the plurality of electrodes may also be provided with a power feeding member, if necessary.
  • the power feeding member provides electrical continuity between a voltage input unit (e.g., a power supply) and the vibrator.
  • a vibration wave driving device includes the vibrator described above and a power feeding member. With this configuration, a vibration wave driving device can be provided in which peeling is less likely to occur between a piezoelectric element and a vibration plate.
  • Fig. 8 is a schematic diagram illustrating a vibration wave driving device according to an embodiment of the present invention.
  • voltage input units 9 are provided to apply voltages to the vibrator 1011 through a power feeding member 7 and through electrical wiring 71 included in the power feeding member 7.
  • the piezoelectric element 101 includes two drive phase electrodes 31. An alternating voltage V1 is applied to the right-hand drive phase electrode 31, and an alternating voltage V2 is applied to the left-hand drive phase electrode 31.
  • the entirety of the piezoelectric element 101 expands and contracts.
  • the vibrator 1011 generates vibration of the mode A.
  • the alternating voltages V1 and V2 are applied at a frequency near the resonant frequency of the mode B in such a manner as to have the same amplitude and phases that are shifted by 180°, the portion of the piezoelectric element 101 corresponding to the right-hand drive phase electrode 31 contracts.
  • the vibrator 1011 generates vibration of the mode B.
  • the resonant frequency of the mode can be measured with an impedance analyzer, for example.
  • phase difference between the alternating voltages V1 and V2 is a phase difference ⁇ between 0° and 180° (0° ⁇ ⁇ ⁇ 180°)
  • composite vectors (V1 + V2) and (V1 - V2) are orthogonal. This indicates that vibration of the mode A and vibration of the mode B are simultaneously generated and the phase difference between the two vibrations is shifted by 90°.
  • the alternating voltages V1 and V2 have the same amplitude and have a phase difference ⁇ other than 0° and 180° satisfying 0° ⁇ ⁇ ⁇ 180°, thereby simultaneously generating vibration of the mode A and vibration of the mode B.
  • the phase difference ⁇ between the alternating voltages V1 and V2 is changed, thereby changing the amplitudes of the vibrations of the mode A and the mode B.
  • a vibration wave motor includes the vibration wave driving device described above and a movable body that is in contact with the vibration plate. With this configuration, a vibration wave motor can be provided in which peeling is less likely to occur between a piezoelectric element and a vibration plate.
  • Fig. 9 is a schematic diagram illustrating a vibration wave motor according to an embodiment of the present invention.
  • a driven body (slider) 8 is disposed on the vibration plate 5 with the projection portions 51 interposed therebetween.
  • the two projection portions 51 are preferably arranged symmetrically about an XZ plane or YZ plane passing through the center of the vibration plate 5.
  • the driven body (slider) 8 is preferably brought into pressure contact with the leading ends of the projection portions 51. This enables the driven body (slider) 8 to move in directions indicated by an arrow in response to the elliptical motion of the projection portions 51.
  • An optical device includes the vibration wave motor described above and an optical member dynamically coupled to the movable body.
  • the term "being dynamically coupled” refers to a state in which two members are directly in contact with each other such that a force generated by coordinate fluctuations, volume change, or shape change of one of the members can be transferred to the other member or a state in which two members are in contact with each other via a third member interposed therebetween.
  • the vibration wave motor described above, the movable body, and the optical member are dynamically coupled to each other, thereby providing an optical device in which peeling is less likely to occur between a piezoelectric element and a vibration plate.
  • Fig. 10 is a schematic diagram illustrating an optical device (focus lens unit in a lens barrel device) according to an embodiment of the present invention.
  • the driven body (slider) 8 is brought into pressure contact with the vibrator 1011.
  • the power feeding member 7 is disposed on the side of the vibrator 1011 close to the surface of the piezoelectric element 101 (not illustrated) having the second electrodes 3 (not illustrated).
  • desired voltages are applied to the vibrator 1011 from the voltage input units 9 (not illustrated) through the power feeding member 7, an elliptical motion is generated at the projection portions 51 (not illustrated) of the vibration plate 5.
  • a holding member 11 is fixed to the vibrator 1011 by welding or the like so as not to generate unnecessary vibration.
  • a movable housing 12 is fixed to the holding member 11 by using screws 13 and is integrated with the vibrator 1011 into a single unit. These members form a vibration wave motor (ultrasonic motor).
  • the movable housing 12 is attached to two guide members 14, thereby enabling the vibration wave motor to move in a straight line along the guide members 14 in both directions (the forward and reverse directions).
  • a lens 16 (optical member) that serves as a focus lens of the lens barrel device.
  • the lens 16 is fixed to a lens holding member 15 and has an optical axis (not illustrated) parallel to the movement direction of the vibration wave motor.
  • the lens holding member 15 moves in a straight line along the two guide members 14, described below, thereby performing focal position adjustment (focus operation).
  • the two guide members 14 are members that enable the movable housing 12 and the lens holding member 15 to fit in with each other such that the movable housing 12 and the lens holding member 15 can move in a straight line. This configuration enables the movable housing 12 and the lens holding member 15 to move in a straight line along the guide members 14.
  • a coupling member 17 is a member that transmits a driving force generated by the vibration wave motor to the lens holding member 15.
  • the coupling member 17 is attached to the lens holding member 15 so as to fit in with the lens holding member 15. This enables the lens holding member 15 to smoothly move in both directions along the two guide members 14 together with the movable housing 12.
  • a sensor 18 reads position information of a scale 19 stuck on a side surface portion of the lens holding member 15 to detect the position of the lens holding member 15 on the guide members 14.
  • the members described above are assembled in the manner described above to construct a focus lens unit in a lens barrel device.
  • an optical device has been described in the context of a lens barrel device for a single-lens reflex camera, a variety of optical devices including a vibration wave motor, such as a compact camera in which a lens and a camera body are formed into a single unit and an electronic still camera, may be used, regardless of the type of camera.
  • a vibration wave motor such as a compact camera in which a lens and a camera body are formed into a single unit and an electronic still camera
  • a vibrator, a method for manufacturing the vibrator, a vibration wave driving device, a vibration wave motor, and an optical device according to embodiments of the present invention will be described hereinafter with reference to examples. However, the present invention is not limited to the following examples.
  • a piezoelectric ceramic was produced by firing a metal oxide powder.
  • XRF X-ray fluorescence
  • 0.16 parts by weight of Mn in terms of metal relative to 100 parts by weight of (Ba 0.85 Ca 0.15 )(Ti 0.93 Zr 0.07 )O 3 were contained, and a lead content was less than 1000 ppm.
  • the piezoelectric ceramic was ground and polished to a thickness of 0.36 mm, the piezoelectric ceramic was cut into pieces of 8.7 ⁇ 5.7 mm 2 in size to obtain a single-piece piezoelectric ceramic formed into a substantially rectangular parallelepiped shape.
  • a silver paste was applied to both surfaces of the piezoelectric ceramic to form drive phase electrodes and a ground electrode, as illustrated in Fig. 8, by using screen printing to produce a piezoelectric element.
  • the ground electrode provides electrical continuity between the front and rear surfaces of the piezoelectric element via a wrap-around electrode.
  • the vibration plate which was made of magnetic stainless steel JIS SUS420J2 and had dimensions of 9.0 ⁇ 5.8 ⁇ 0.3 mm 3 , was used. Further, the vibration plate was provided with support portions out of a plane thereof and projection portions in the plane thereof, as illustrated in Fig. 7.
  • An epoxy-based liquid adhesive (with a glass transition temperature of 120°C) was used as a resin precursor, and a sufficient amount of the resin precursor was applied to a bonding surface of the vibration plate by using a dispenser. Then, a ground electrode surface of the piezoelectric element and the vibration plate were brought into pressure contact with each other for 3 minutes, and the resin precursor was caused to extend from a bonding region to cover a pair of opposing side surface portions of the piezoelectric element.
  • the resin precursor was not caused to extend out of the plane of the vibration plate.
  • the piezoelectric element and the vibration plate were placed into a drying oven in this state and were held at 130°C for 60 minutes to cure the resin precursor, thereby forming a resin layer.
  • a power feeding member for the drive phase electrodes and the ground electrode was formed, by thermocompression bonding, on the surface of the piezoelectric element having the second electrodes to which the vibration plate did not adhere.
  • the power feeding member which was formed of a flexible cable, was connected to the piezoelectric element by using an anisotropic conductive film (ACF).
  • ACF anisotropic conductive film
  • the piezoelectric ceramic was subjected to polarization processing at 100°C. Specifically, each of the two drive phase electrodes of the piezoelectric element was brought into contact with a contact pin for polarization to apply a voltage by using the vibration plate as ground. At this time, direct-current voltages were applied to the piezoelectric ceramic for 30 minutes to achieve a field strength of 1.0 kV/mm.
  • a vibrator A according to the present invention (hereinafter referred to as the vibrator A) was obtained.
  • the resin layer of the vibrator A was observed with an optical microscope from the surface having the drive phase electrodes. As a result, as illustrated in Fig. 3D, the resin layer covered all the side surfaces.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element of the vibrator A to the height of the side surface of the piezoelectric element, the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element were measured.
  • one of vibrators A was cut along a direction parallel to the long sides of the piezoelectric ceramic and the cross section of the vibrator A was observed with an SEM.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element to the height of the side surface of the piezoelectric element was 65%, and the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other was 4.2 ⁇ m. Further, the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element body was 0.35 mm.
  • the alternating voltages V1 and V2 (each having an amplitude of 10 Vpp) were applied to the vibration wave driving device A via the drive phase electrodes, and the displacement of the vibrator A was measured with a laser-Doppler vibrometer.
  • the phase difference between the alternating voltages V1 and V2 was set to 0°
  • out-of-plane vibration mode A with two nodal lines was generated in the vibrator A.
  • the phase difference between the alternating voltages V1 and V2 was set to 180°
  • out-of-plane vibration mode B with three nodal lines, which was substantially perpendicular to the out-of-plane vibration mode A was generated in the vibrator A.
  • a vibrator B was produced through steps similar to those in Example 1, except that a resin layer protruding in the long-side direction of the piezoelectric element was removed before the resin layer was cured.
  • the shape of the resin layer of the vibrator B was measured through a step similar to that in Example 1. As a result, as illustrated in Fig. 3C, the resin layer covered a pair of opposing side surface portions.
  • the area coverage ratio of the resin layer within the bonding region of the vibrator B was measured through a step similar to that in Example 1. As a result of image analysis, the area coverage ratio was 95%.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element of the vibrator B to the height of the side surface of the piezoelectric element was measured through a step similar to that in Example 1.
  • the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element were measured.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element to the height of the side surface of the piezoelectric element was 61%, and the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other was 4.2 ⁇ m. Further, the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element was 0.35 mm.
  • a vibration wave driving device B as illustrated in Fig. 8 was produced through a step similar to that in Example 1.
  • the alternating voltages V1 and V2 (each having an amplitude of 10 Vpp) were applied to the vibration wave driving device B via the drive phase electrodes, and the displacement of the vibrator B was measured with a laser-Doppler vibrometer. As a result, the resin layer of the vibrator B was found to cover the antinodal lines of the vibration mode B.
  • a vibrator C was produced through steps similar to those in Example 1, except that a resin layer protruding in the short-side direction of the piezoelectric element was removed before the resin layer was cured.
  • the shape of the resin layer of the vibrator C was measured through a step similar to that in Example 1. As a result, as illustrated in Fig. 3B, the resin layer covered a pair of opposing side surface portions.
  • the area coverage ratio of the resin layer within the bonding region of the vibrator C was measured through a step similar to that in Example 1. As a result of image analysis, the area coverage ratio was 96%.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element of the vibrator C to the height of the side surface of the piezoelectric element was measured through a step similar to that in Example 1.
  • the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element were measured.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element to the height of the side surface of the piezoelectric element was 61%, and the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other was 4.2 ⁇ m. Further, the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element was 0.36 mm.
  • a vibration wave driving device C as illustrated in Fig. 8 was produced through a step similar to that in Example 1.
  • the alternating voltages V1 and V2 (each having an amplitude of 10 Vpp) were applied to the vibration wave driving device C via the drive phase electrodes, and the displacement of the vibrator C was measured with a laser-Doppler vibrometer. As a result, the resin layer of the vibrator C was found to cover the antinodal lines of the vibration mode A.
  • a vibrator D was produced through steps similar to those in Example 1, except that a resin layer protruding in the short-side direction of the piezoelectric element was removed before the resin layer was cured.
  • the shape of the resin layer of the vibrator D was measured through a step similar to that in Example 1. As a result, as illustrated in Fig. 3A, the resin layer covered at least a portion of the side surfaces.
  • the area coverage ratio of the resin layer within the bonding region of the vibrator D was measured through a step similar to that in Example 1. As a result of image analysis, the area coverage ratio was 97%.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element of the vibrator D to the height of the side surface of the piezoelectric element was measured through a step similar to that in Example 1.
  • the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element were measured.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element to the height of the side surface of the piezoelectric element was 60%.
  • the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other was 6.1 ⁇ m, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element was 0.34 mm.
  • a vibration wave driving device D as illustrated in Fig. 8 was produced through a step similar to that in Example 1.
  • the alternating voltages V1 and V2 (each having an amplitude of 10 Vpp) were applied to the vibration wave driving device D via the drive phase electrodes, and the displacement of the vibrator D was measured with a laser-Doppler vibrometer. As a result, the resin layer of the vibrator D was found to cover the antinodal lines of the vibration mode A.
  • a vibrator E was produced through steps similar to those in Example 1, except that the piezoelectric element and the vibration plate were brought into pressure contact for 5 minutes.
  • the shape of the resin layer of the vibrator E was measured through a step similar to that in Example 1. As a result, as illustrated in Fig. 3D, the resin layer covered all the side surfaces.
  • the area coverage ratio of the resin layer within the bonding region of the vibrator E was measured through a step similar to that in Example 1. As a result of image analysis, the area coverage ratio was 58%.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element of the vibrator E to the height of the side surface of the piezoelectric element was measured through a step similar to that in Example 1.
  • the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element were measured.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element to the height of the side surface of the piezoelectric element was 65%.
  • the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other was 5.3 ⁇ m, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element was 0.35 mm.
  • a vibration wave driving device E as illustrated in Fig. 8 was produced through a step similar to that in Example 1.
  • the alternating voltages V1 and V2 (each having an amplitude of 10 Vpp) were applied to the vibration wave driving device E via the drive phase electrodes, and the displacement of the vibrator E was measured with a laser-Doppler vibrometer. As a result, the resin layer of the vibrator E was found to cover the antinodal lines of the vibration mode A and the antinodal lines of the vibration mode B.
  • a vibrator F was produced through steps similar to those in Example 1, except that the piezoelectric element and the vibration plate were brought into pressure contact for 1 minute.
  • the shape of the resin layer of the vibrator F was measured through a step similar to that in Example 1. As a result, as illustrated in Fig. 3D, the resin layer covered all the side surfaces.
  • the area coverage ratio of the resin layer within the bonding region of the vibrator F was measured through a step similar to that in Example 1. As a result of image analysis, the area coverage ratio was 65%.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element of the vibrator F to the height of the side surface of the piezoelectric element was measured through a step similar to that in Example 1.
  • the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element were measured.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element to the height of the side surface of the piezoelectric element was 4%.
  • the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other was 2.8 ⁇ m, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element was 0.35 mm.
  • a vibration wave driving device F as illustrated in Fig. 8 was produced through a step similar to that in Example 1.
  • the alternating voltages V1 and V2 (each having an amplitude of 10 Vpp) were applied to the vibration wave driving device F via the drive phase electrodes, and the displacement of the vibrator F was measured with a laser-Doppler vibrometer. As a result, the resin layer of the vibrator F was found to cover the antinodal lines of the vibration mode A and the antinodal lines of the vibration mode B.
  • a vibrator G was produced through steps similar to those in Example 6, except that the amount of the resin precursor was reduced by 20% when the piezoelectric element and the vibration plate were brought into pressure contact.
  • the shape of the resin layer of the vibrator G was measured through a step similar to that in Example 1. As a result, as illustrated in Fig. 3D, the resin layer covered all the side surfaces.
  • the area coverage ratio of the resin layer within the bonding region of the vibrator G was measured through a step similar to that in Example 1. As a result of image analysis, the area coverage ratio was 92%.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element of the vibrator G to the height of the side surface of the piezoelectric element was measured through a step similar to that in Example 1.
  • the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element were measured.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element to the height of the side surface of the piezoelectric element was 35%.
  • the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other was 0.4 ⁇ m, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element was 0.35 mm.
  • a vibration wave driving device G as illustrated in Fig. 8 was produced through a step similar to that in Example 1.
  • the alternating voltages V1 and V2 (each having an amplitude of 10 Vpp) were applied to the vibration wave driving device G via the drive phase electrodes, and the displacement of the vibrator G was measured with a laser-Doppler vibrometer. As a result, the resin layer of the vibrator G was found to cover the antinodal lines of the vibration mode A and the antinodal lines of the vibration mode B.
  • a vibrator H was produced through steps similar to those in Example 1, except for the composition of the piezoelectric ceramic in which the Mn content was 0.16 parts by weight in terms of metal and, in addition, the Bi content was 0.03 parts by weight in terms of metal with respect to 100 parts by weight of (Ba 0.85 Ca 0.15 )(Ti 0.93 Zr 0.07 )O 3 .
  • the shape of the resin layer of the vibrator H was measured through a step similar to that in Example 1. As a result, as illustrated in Fig. 3D, the resin layer covered all the side surfaces.
  • the area coverage ratio of the resin layer within the bonding region of the vibrator H was measured through a step similar to that in Example 1. As a result of image analysis, the area coverage ratio was 91%.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element of the vibrator B to the height of the side surface of the piezoelectric element was measured through a step similar to that in Example 1.
  • the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element were measured.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element to the height of the side surface of the piezoelectric element was 40%.
  • the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other was 3.0 ⁇ m, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element was 0.35 mm.
  • a vibration wave driving device H as illustrated in Fig. 8 was produced through a step similar to that in Example 1.
  • the alternating voltages V1 and V2 (each having an amplitude of 10 Vpp) were applied to the vibration wave driving device H via the drive phase electrodes, and the displacement of the vibrator H was measured with a laser-Doppler vibrometer. As a result, the resin layer of the vibrator H was found to cover the antinodal lines of the vibration mode A and the antinodal lines of the vibration mode B.
  • a vibrator I was produced through steps similar to those in Example 1, except for the composition of the piezoelectric ceramic in which the Bi content was 0.03 parts by weight in terms of metal with respective to 100 parts by weight of (Ba 0.85 Ca 0.15 )TiO 3 .
  • the shape of the resin layer of the vibrator I was measured through a step similar to that in Example 1. As a result, as illustrated in Fig. 3D, the resin layer covered all the side surfaces.
  • the area coverage ratio of the resin layer within the bonding region of the vibrator I was measured through a step similar to that in Example 1. As a result of image analysis, the area coverage ratio was 90%.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element of the vibrator I to the height of the side surface of the piezoelectric element was measured through a step similar to that in Example 1.
  • the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element were measured.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element to the height of the side surface of the piezoelectric element was 60%.
  • the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other was 7.1 ⁇ m, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element was 0.35 mm.
  • a vibration wave driving device I as illustrated in Fig. 8 was produced through a step similar to that in Example 1.
  • the alternating voltages V1 and V2 (each having an amplitude of 10 Vpp) were applied to the vibration wave driving device I via the drive phase electrodes, and the displacement of the vibrator I was measured with a laser-Doppler vibrometer. As a result, the resin layer of the vibrator I was found to cover the antinodal lines of the vibration mode A and the antinodal lines of the vibration mode B.
  • a vibrator J was produced through steps similar to those in Example 1, except that the composition of the piezoelectric ceramic was Pb(Zr 0.52 Ti 0.48 )O 3 , the piezoelectric ceramic was ground and polished to a thickness of 0.42 mm, and the piezoelectric ceramic was subjected to polarization processing at a temperature of 150°C with a field strength of 2.0 kV/ mm.
  • the shape of the resin layer of the vibrator J was measured through a step similar to that in Example 1. As a result, as illustrated in Fig. 3D, the resin layer covered all the side surfaces.
  • the area coverage ratio of the resin layer within the bonding region of the vibrator J was measured through a step similar to that in Example 1. As a result of image analysis, the area coverage ratio was 96%.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element of the vibrator J to the height of the side surface of the piezoelectric element was measured through a step similar to that in Example 1.
  • the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element were measured.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element to the height of the side surface of the piezoelectric element was 60%.
  • the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other was 6.8 ⁇ m, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element was 0.41 mm.
  • a vibration wave driving device J as illustrated in Fig. 8 was produced through a step similar to that in Example 1.
  • the alternating voltages V1 and V2 (each having an amplitude of 10 Vpp) were applied to the vibration wave driving device J via the drive phase electrodes, and the displacement of the vibrator J was measured with a laser-Doppler vibrometer. As a result, the resin layer of the vibrator J was found to cover the antinodal lines of the vibration mode A and the antinodal lines of the vibration mode B.
  • a piezoelectric ceramic was produced by firing a metal oxide powder.
  • XRF X-ray fluorescence
  • 0.16 parts by weight of Mn in terms of metal relative to 100 parts by weight of (Ba 0.85 Ca 0.15 )(Ti 0.93 Zr 0.07 )O 3 were contained, and a lead content was less than 1000 ppm.
  • the piezoelectric ceramic was ground and polished to a thickness of 0.36 mm, the piezoelectric ceramic was cut into pieces of 8.7 ⁇ 5.7 mm 2 in size to obtain a single-piece piezoelectric ceramic formed into a substantially rectangular parallelepiped shape.
  • a silver paste was applied to both surfaces of the piezoelectric ceramic to form drive phase electrodes and a ground electrode, as illustrated in Fig. 8, by using screen printing to produce a piezoelectric element.
  • the vibration plate which was made of magnetic stainless steel JIS SUS420J2 and had dimensions of 9.0 ⁇ 5.8 ⁇ 0.3 mm 3 , was used. Further, the vibration plate was provided with support portions out of a plane thereof and projection portions in the plane thereof, as illustrated in Fig. 7.
  • An epoxy-based liquid adhesive (with a glass transition temperature of 120°C) was used as a resin precursor, and the resin precursor was applied to a bonding surface of the vibration plate by using a dispenser. Then, a ground electrode surface of the piezoelectric element and the vibration plate were brought into pressure contact with each other for 3 minutes, and a rubber was placed around the piezoelectric element to prevent the resin precursor from extending from a bonding region. Thereafter, the rubber was removed and the piezoelectric element, and the vibration plate were placed into a drying oven and were held at 130°C for 60 minutes to cure the resin precursor, thereby forming a resin layer.
  • a power feeding member for the drive phase electrodes and the ground electrode was formed, by thermocompression bonding, on the surface of the piezoelectric element having the second electrodes to which the vibration plate did not adhere.
  • the power feeding member which was formed of a flexible cable, was connected to the piezoelectric element by using an anisotropic conductive film (ACF).
  • ACF anisotropic conductive film
  • the piezoelectric ceramic was subjected to polarization processing at 100°C. Specifically, each of the two drive phase electrodes of the piezoelectric element was brought into contact with a contact pin for polarization to apply a voltage by using the vibration plate as ground. At this time, direct-current voltages were applied to the piezoelectric ceramic for 30 minutes to achieve a field strength of 1.0 kV/mm.
  • the resin layer of the vibrator K was observed with an optical microscope from the surface having the drive phase electrodes. As a result, the resin layer covered none of the side surface portions.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element of the vibrator K to the height of the side surface of the piezoelectric element was measured.
  • the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element one of vibrators K was cut along a direction parallel to the long sides of the piezoelectric ceramic and the cross section of the vibrator K was observed with an SEM.
  • the ratio of the maximum height of a resin layer formed in a portion of a side surface of the piezoelectric element to the height of the side surface of the piezoelectric element was 0%.
  • the maximum thickness of a resin layer formed in a region where the vibration plate and the piezoelectric element face each other was 4.2 ⁇ m, and the thickness of the piezoelectric ceramic in a direction extending along the side surfaces of the piezoelectric element was 0.35 mm.
  • the alternating voltages V1 and V2 (each having an amplitude of 10 Vpp) were applied to the vibration wave driving device K via the drive phase electrodes, and the displacement of the vibrator K was measured with a laser-Doppler vibrometer.
  • vibration mode A with two nodal lines was generated in the vibrator K.
  • vibration mode B with three nodal lines, which is substantially perpendicular to the vibration mode A, was generated in the vibrator K.
  • the respective vibration plates of the vibrators A to J produced in Examples 1 to 10 were each brought into contact with a driven body (slider) to produce a vibration wave motor as illustrated in Fig. 9 (Examples 11 to 20).
  • the alternating voltages V1 and V2 (each having an amplitude of 100 Vpp) were applied to the each of the produced vibration wave motors via the drive phase electrodes.
  • the driven body (slider) was driven to reciprocate 100 times in the direction indicated by the arrow in Fig. 9 with the phase difference ⁇ between the alternating voltages V1 and V2 being set to 90° and -90° repeatedly 100 times in such a manner as 90° ⁇ -90° ⁇ 90° ⁇ -90°.
  • a vibration wave motor as illustrated in Fig. 9 was produced, driven, and evaluated by using the vibrator K produced in Comparative Example 1 through steps similar to those in Examples 11 to 20 (Comparative Example 2).
  • An optical device as illustrated in Fig. 10 was produced by dynamically coupling the vibration wave motor produced in Example 11, a movable body, and an optical member to each other (Example 21). Further, an optical device as illustrated in Fig. 10 was produced by dynamically coupling the vibration wave motor produced in Comparative Example 2, a movable body, and an optical member to each other (Comparative Example 3). It was observed that both optical devices performed an autofocus operation in accordance with the application of alternating voltages. In the optical device according to Comparative Example 3, however, peeling occurred between the piezoelectric element and the vibration plate after the autofocus operation was performed 100 times, and a reduction in area coverage ratio greater than or equal to 30% was observed.
  • An embodiment of the present invention can provide a vibrator in which peeling is less likely to occur between a piezoelectric element and a vibration plate.
  • a method for manufacturing a vibrator according to another embodiment of the present invention can produce a vibrator with high yield in which peeling is less likely to occur between a piezoelectric element and a vibration plate.
  • embodiments of the present invention can provide a vibration wave driving device, a vibration wave motor, and an optical device in which peeling is less likely to occur between a piezoelectric element and a vibration plate.
  • the vibrator according to the embodiment of the present invention is applicable to an electronic device including an electronic component and a vibrator.
  • piezoelectric ceramic 101 piezoelectric element 1011 vibrator 2 first electrode 21 ground electrode 3 second electrode 31 drive phase electrode 4 resin layer 41 bonding region 5 vibration plate 51 projection portion 6 support portion 7 power feeding member 71 electrical wiring 8 driven body (slider) 9 voltage input unit 11 holding member 12 movable housing 13 screw 14 guide member 15 lens holding member 16 lens 17 coupling member 18 sensor 19 scale

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