PIEZOELECTRIC ELEMENT, MULTI-LAYER PIEZOELECTRIC ELEMENT, LIQUID DISCHARGE HEAD, LIQUID DISCHARGE AP

专利摘要:
piezoelectric element, multilayer piezoelectric element, liquid discharge head, liquid discharge apparatus, ultrasonic motor, optical apparatus, and electronic apparatus. a lead-free piezoelectric element that operates stably over a wide operating temperature range contains a lead-free piezoelectric material. the piezoelectric element includes a first electrode, a second electrode, and a piezoelectric material that includes a perovskite type metal oxide represented by (ba1-xcax) to (ti1-yzry) o3 (where 1.00 ? to ? 1 .01, 0.02 ? x ? 0.30, 0.020 ? y ? 0.095, and y ? x) as a major component and manganese incorporated in the perovskite type metal oxide. the manganese content in relation to 100 parts by weight of perovskite type metal oxide is 0.02 parts by weight or more and 0.40 parts by weight or less on a metal basis.
公开号:BR112014000104B1
申请号:R112014000104-9
申请日:2012-06-26
公开日:2021-08-03
发明作者:Jumpei Hayashi；Kenichi Takeda；Shinya Koyama；Kenichi Akashi；Tatsuo Furuta
申请人:Canon Kabushiki Kaisha；
IPC主号:

专利说明:

DESCRIPTION Technical Field
[0001] The present invention generally refers to piezoelectric elements, piezoelectric elements consisting of multiple layers, liquid discharge heads, liquid discharge devices, ultrasonic motors, optical devices, and electronic devices. In particular, the present invention relates to a piezoelectric element, a multilayer piezoelectric element, a liquid discharge head, a liquid discharge apparatus, an ultrasonic motor, an optical apparatus, and an electronic apparatus, which do not contain lead and operate stably in the operating temperature ranges. prior art
[0002] ABO3 perovskite type metal oxides, such as lead zirconate titanate (referred to as "the PZT" hereinafter), are typically used as piezoelectric materials. Since PZT contains lead as the element of Site A, a concern was raised about the impact of PZT on the environment. Thus, piezoelectric materials using lead-free perovskite-type metal oxides are highly desirable.
[0003] An example of a lead-free piezoelectric material that contains a perovskite type metal oxide is barium titanate. Studies on and development of barium titanate based materials were conducted to improve the properties of barium titanate and devices using such materials were exposed. PTL 1 exposes a piezoelectric element that uses barium titanate with the addition of Mn, Fe, or Cu and with some of the A sites being replaced by Ca. These piezoelectric elements have mechanical quality factors superior to those of barium titanate, but have low piezoelectric properties. Thus, high voltage was required to drive the piezoelectric elements.
[0004] PTL 2 exposes an actuator and a liquid discharge head that use a material prepared by adding Ba and B to barium titanate. This material has a low sintering temperature advantage, but has a piezoelectric constant d33 as low as 65 [C/N]. Thus, high voltage was required to drive the piezoelectric element.
[0005] Piezoelectric materials that have a Curie temperature of 80°C or lower may depolarize in a harsh environment, such as car compartments in the summer sun, and may lose piezoelectricity as a result. Piezoelectricity can be lost by heat generated as a result of actuating actuators. Quote List
[0006] Patent Literature
[0007] PTL 1 Japanese Patent, open for public exhibition, No. 2010-120835;
[0008] PTL 2 Japanese Patent, open for public exhibition, No. 2011 -032111. Invention Summary Technical Problem
[0009] The invention provides a lead-free piezoelectric element that operates stably over a wide operating temperature range. Solution to Problem
[0010] A first aspect of the invention provides a piezoelectric element that includes a first electrode, a second electrode, and a piezoelectric material. The piezoelectric material includes a perovskite-type metal oxide represented by the general formula (1) as a major component, and manganese incorporated into the perovskite-type metal oxide: (Bai-xCax) to (Tii-yZry) O3 (in that 1.00 < a < 1.01, 0.02 < x < 0.30, 0.020 < y < 0.095, and y < x) (1)
[0011] The manganese content in relation to 100 parts by weight of perovskite type metal oxide is 0.02 parts by weight or more and 0.40 parts by weight or less on a metal basis.
[0012] A second aspect of the present invention provides a multilayer piezoelectric element that includes layers of piezoelectric material and electrodes including an inner electrode. The layers of piezoelectric material and electrodes are stacked alternately. The piezoelectric material layers contain a perovskite-type metal oxide represented by the general formula (1) as a major component, and manganese incorporated into the perovskite-type metal oxide: (Ba1-xCax) to (Ti1-yZry) O3 (where 1.00 < a < 1.01, 0.02 < x < 0.30, 0.020 < y < 0.095, and y < x) (1)
[0013] The manganese content in relation to 100 parts by weight of perovskite type metal oxide is 0.02 parts by weight or more and 0.40 parts by weight or less on a metal basis.
[0014] A third aspect of the present invention provides a liquid discharge head that includes a liquid reservoir including a vibration unit that includes the piezoelectric element or the multilayer piezoelectric element described above, and a discharge port in communication with the liquid reservoir. A fourth aspect of the present invention provides a liquid discharge apparatus which includes a transport unit configured to transport a recording medium and the liquid discharge head described above.
[0015] A fifth aspect of the present invention provides an ultrasonic motor that includes a vibrating element including the piezoelectric element or the multilayer piezoelectric element described above and a movable element in contact with the vibrating element. A sixth aspect of the present invention provides an optical apparatus that includes a drive unit including the ultrasonic motor described above. A seventh aspect of the present invention provides an electronic apparatus that includes a piezoelectric acoustic component including the piezoelectric element or the multilayer piezoelectric element described above. Advantageous Effects of the Invention
[0016] A lead-free piezoelectric element that operates stably over a wide operating temperature range can be provided. A liquid discharge head, a liquid discharge apparatus, an ultrasonic motor, an optical apparatus, and an electronic apparatus using this lead-free piezoelectric element may also be provided. Brief Description of Drawings
[0017] Figure 1 is a schematic view showing a piezoelectric element according to an embodiment of the invention.
[0018] Figures 2A and 2B show a liquid discharge head according to an embodiment of the invention.
[0019] Figures 3A and 3B are each a schematic view showing an ultrasonic motor according to an embodiment of the invention.
[0020] Figure 4 is a graph showing the relationship between x and y of piezo ceramics from Production Examples 1 to 73.
[0021] Figures 5A and 5B are each a cross-sectional view showing a multilayer piezoelectric element according to an embodiment of the invention.
[0022] Figure 6 is a schematic view showing a liquid discharging apparatus according to an embodiment of the invention.
[0023] Figure 7 is another schematic view showing the liquid discharge apparatus.
[0024] Figures 8A and 8B are schematic views showing an optical apparatus according to an embodiment of the invention.
[0025] Figure 9 is a schematic view showing the optical apparatus.
[0026] Figure 10 is a schematic view showing an electronic apparatus according to an embodiment of the invention. Description of Modalities
[0027] Modalities of the invention will now be described.
[0028] Figure 1 is a schematic view showing a piezoelectric element according to an embodiment of the present invention. The piezoelectric element includes a piezoelectric material 2, and a first electrode 1 and a second electrode 3 associated with the piezoelectric material 2.
[0029] The piezoelectric element includes at least a first electrode, a piezoelectric material, and a second electrode. The piezoelectric material contains a perovskite-type metal oxide represented by the general formula (1) as a major component and manganese (Mn) incorporated in the perovskite-type metal oxide: (Bai-xCax) to (Tii-yZry) O3 (where 1.00 < a < 1.01, 0.02 < x < 0.30, 0.020 < y < 0.095, and y < x) (1)
[0030] The Mn content with respect to 100 parts by weight of metal oxide is 0.02 parts by weight or more and 0.40 parts by weight or less on a metal basis.
[0031] Each of the first and second electrodes is constituted by an electrically conductive layer having a thickness of about 5 nm to about 2000 nm. The material used to form the electrodes can be any material commonly used in piezoelectric elements. Examples thereof include metals such as Ti, Pt, Ta, Ir, Sr, In, Sn, Au, Al, Fe, Cr, Ni, Pd, Ag, and Cu and compounds thereof.
[0032] The first and second electrodes can each be composed of one of these materials, or they can each be constituted by a structure consisting of multiple layers prepared by stacking two or more of these materials. The first and second electrodes can be composed of materials different from each other.
[0033] The method for producing the first and second electrodes can be any. For example, electrodes can be formed by baking a metal slurry, by sputter metallization, or by vapor deposition. The first and second electrodes can be standard when desired.
[0034] In this description, a perovskite-type metal oxide refers to a metal oxide having a perovskite-type structure that is ideally a cubic crystal structure, as described in Iwanami Rikagaku Jiten, 5th edition (published in gasket February 20, 1998 by Iwanami Shoten Publishers). A metal oxide having a perovskite-like structure is usually expressed by a chemical formula, ABO3. Element A and element B in a perovskite-type metal oxide take the form of ions and occupy particular positions in a unit cell, called A sites and B sites, respectively. For example, in a unit cell of a cubic crystal system, element A occupies the vertices of the cube and element B occupies the position of the center of the cube's body. The O element is oxygen in the form of an anion and occupies the face center positions of the cube.
[0035] In the metal oxide represented by the general formula (1) above, barium (Ba) and calcium (Ca) are metal elements that occupy the A sites and titanium (Ti) and zirconium (Zr) are metal elements that occupy the B sites. Note that some of the Ba and Ca atoms can occupy the B sites and/or some of the Ti and Zr atoms can occupy the A sites.
[0036] In the general formula (1), the molar ratio of the element from site B to O is 1:3. A metal oxide having a B/O site element ratio slightly deviated from that, for example, 1.00:2.94 to 1.00:3.06, is still included within the scope of the present invention provided that the metal oxide metal has a perovskite-like structure as a main phase.
[0037] Structural analysis through X-ray diffraction or electron beam diffraction can be used to determine whether a metal oxide has a perovskite-like structure, for example.
The piezoelectric material can take any form, for example, a ceramic, powder, single crystal, film, mud, or the like, but is preferably a ceramic. In this description, a "ceramic" refers to an aggregate (also referred to as a volume) of crystal grains basically composed of a metal oxide and consolidated by heat treatment, and is a polycrystal. A "ceramic" can also refer to a ceramic that has been processed after sintering.
[0039] In the general formula (1) above, a represents the ratio between the total molar amount of Ba and Ca at sites A and the total molar amount of Ti and Zr at sites B and is in a range of 1.00 < a < 1.01. When a is less than 1.00, abnormal grain growth immediately occurs and the mechanical strength of the material is decreased. When a is greater than 1.01, the temperature required for grain growth becomes excessively high and sintering cannot be achieved in a typical combustion furnace. Here, "sintering cannot be achieved" refers to a state in which the density is not sufficiently increased or a large number of pores and defects are present in the piezoelectric material.
[0040] In the general formula (1), x represents the molar ratio of Ca at sites A and is in a range of 0.02 < x < 0.30. When x is less than 0.02, the dielectric loss (tanδ) increases. When dielectric loss is increased, the amount of heat generated when a voltage is applied to the piezoelectric element to drive the piezoelectric element increases and the driving efficiency may be degraded. When x is greater than 0.30, the piezoelectric property may not be sufficient.
[0041] In the general formula (1), y represents the molar ratio of Zr at the B sites and is in a range of 0.020 < y < 0.095. When y is less than 0.020, the piezoelectric property may not be sufficient. When y is greater than 0.095, the Curie temperature (Tc) becomes less than 85°C and the piezoelectric property will be lost at high temperature.
[0042] In this description, a Curie temperature refers to a temperature at which ferroelectricity is lost. Examples of the method for detecting temperature include a method of directly measuring temperature at which ferroelectricity is lost by varying the measurement temperature and a method of measuring the dielectric constant using AC fields per minute while varying the measurement temperature and determining the temperature at which the dielectric constant is maximal.
[0043] In the general formula (1), the molar ratio of Ca x and the molar ratio of Zr y satisfy y < x. When y > x, the dielectric loss may increase and the insulating property may be insufficient. When all of the ranges concerning ax and y, described so far, are satisfied simultaneously, the crystal structure phase transition temperature (phase transition point) can be shifted from near ambient temperature to a temperature below the range of operating temperature and thus the device can be stably actuated over a wide temperature range.
[0044] The method for determining the composition of the piezoelectric material used in the piezoelectric element is not particularly limited. Examples of the method include X-ray fluorescence analysis, inductively coupled plasma atomic emission spectroscopy (ICP), and atomic absorption spectrometry. The weight ratios and compositional ratios of the elements contained in the piezoelectric material can be determined by any of these methods.
[0045] The piezoelectric material used in the piezoelectric element has a Mn content of 0.02 parts by weight or more and 0.40 parts by weight or less on a metal basis relative to 100 parts by weight of metal oxide. Piezoelectric material having an Mn content within this range exhibits a better insulation property and a better mechanical quality factor. Here, the mechanical quality factor refers to a factor that indicates an elastic loss caused by oscillation when piezoelectric material is used in an oscillator. The magnitude of the mechanical quality factor is looked at as an acuity of a resonance curve in measuring impedance. In other words, the mechanical quality factor is a factor that indicates the acuity of an oscillator's resonance. Presumably, the insulation property and the mechanical quality factor are improved by introducing defective dipoles due to Mn having a valence different from that of Ti and Zr and the generation of internal electric fields that result from this. When an internal electric field is present, a piezoelectric element formed using the piezoelectric material and operated by applying voltage exhibits long-term reliability.
[0046] The term "on a metal basis" with reference to the Mn content refers to a value determined by first determining the oxide-based amounts of the elements that constitute the metal oxide represented by the general formula (1) based on the Ba, Ca, Ti, Zr, and Mn contents, measured by XRF, ICP atomic emission spectroscopy, atomic absorption spectroscopy, or similar and then calculation of the ratio between the weight of Mn in relation to 100 parts by weight of the quantity total of the elements that constitute the metal oxide on a weight basis.
[0047] When the Mn content is less than 0.02 parts by weight, the effect of the polarization treatment is not sufficient to trigger the device. When the Mn content is greater than 0.40 parts by weight, the piezoelectric property is not sufficient and crystals having a hexagonal structure that does not contribute to the piezoelectric property emerge.
[0048] Manganese is not limited to metallic Mn and can take any form as long as manganese is contained as a component in the piezoelectric material. For example, manganese can be dissolved at B sites or can be included in grain boundaries. Manganese can take the form of a metal, ion, oxide, metal salt, or complex in the piezoelectric material. Preferably, manganese is dissolved at the B-sites, from the standpoints of insulation property and sintering ability. When manganese is dissolved at B sites, a preferable range of the A/B molar ratio for resonator devices (rigid devices), such as piezoelectric sensors, piezoelectric transformers, and ultrasonic motors, which operate at resonant frequencies, is 0.993 < A/B < 0.998, where A is the molar amount of Ba and Ca at sites A and B is the molar amount of Ti, Zr, and Mn at sites B. A piezoelectric element that has an A/B within this range exhibits a high constant piezoelectric and a high mechanical quality factor and thus form a device that has superior durability. A preferable range of A/B for displacement actuators (soft devices) such as optical pickup actuators and liquid discharge heads that operate at non-resonant frequencies is 0.996 < A/B < 0.999. Piezoelectric elements that have an A/B within these ranges can exhibit a high piezoelectric constant, a low dielectric loss, and high durability.
[0049] The piezoelectric material used in the piezoelectric element may contain components (hereinafter referred to as auxiliary components) other than the compound represented by the general formula (1) and Mn, provided that the properties are not modified. The total content of the auxiliary components can be 1.2 parts by weight or less with respect to 100 parts by weight of the metal oxide represented by the general formula (1). When the auxiliary component content exceeds 1.2 parts by weight, the piezoelectric property and the insulating property of the piezoelectric material may be degraded. The content of metal elements other than Ba, Ca, Ti, Zr, and Mn among the auxiliary components is preferably 1.0 parts by weight or less on an oxide basis, or 0.9 parts by weight or less on an oxide basis. of metal in relation to the piezoelectric material. In this description, "metal elements" include semimetal elements such as Si, Ge, and Sb.
[0050] When the content of metal elements other than Ba, Ca, Ti, Zr, and Mn among the auxiliary components exceeds 1.0 parts by weight on an oxide basis or 0.9 parts by weight on a metal basis with respect to piezoelectric material, the piezoelectric property and the insulating property of the piezoelectric material can be significantly degraded. The total content of Li, Na, Mg, and Al among the auxiliary components can be 0.5 parts by weight or less on a metal basis relative to the piezoelectric material. When the total content of Li, Na, Mg, and Al among the auxiliary components exceeds 0.5 parts by weight on a metal basis relative to the piezoelectric material, insufficient sintering may occur. The total of Y and V among auxiliary components can be 0.2 parts by weight or less on a metal basis relative to the piezoelectric material. When the total content of Y and V exceeds 0.2 parts by weight on a metal basis relative to the piezoelectric material, the polarization treatment can become difficult.
[0051] Examples of auxiliary components include sintering aids such as Si and Cu. Commercially available Ba and Ca raw materials contain Sr as an unavoidable impurity and thus the piezoelectric material may contain an amount of Sr impurity. Similarly, a commercially available raw material contains Nb as an unavoidable impurity and a commercially available Zr feedstock contains Hf as an unavoidable impurity. Thus, the piezoelectric material may contain impurity amounts of Nb and Hf.
[0052] The method for measuring the weights of auxiliary components is not particularly limited. Examples of the method include X-ray fluorescence analysis, ICP atomic emission spectroscopy, and atomic absorption spectrometry.
[0053] The piezoelectric material used in the piezoelectric element may consist of crystal grains having a mean circular equivalent diameter of 1 μm or greater and 10 μm or less. When the average circular equivalent diameter is within this range, the piezoelectric material can exhibit good piezoelectric property and good mechanical strength. When the mean circular equivalent diameter is less than 1 µm, the piezoelectric property may be insufficient. When the mean circular equivalent diameter is greater than 10 µm, the mechanical strength may be degraded. A more preferable range is 3 μm or greater and 8 μm or less.
[0054] In this description, a "circular equivalent diameter" refers to what is generally known as a "projected area diameter" in microscopy and indicates the diameter of a circle that has the same area as the projected area of a crystal grain. . In this invention, the method for measuring the circular equivalent diameter is not particularly limited. For example, an image of a surface of a piezoelectric material can be taken with a polarizing microscope or a scanning electron microscope and the image processed to determine the equivalent circular diameter. Since the optimal magnification differs depending on the grain diameter to be analyzed, an optical and an electron microscope can be appropriately used. The equivalent circular diameter can be determined from an image of a polished surface or a cross section rather than a material surface.
[0055] The relative density of the piezoelectric material used in the piezoelectric element can be 93% or higher and 100% or lower.
[0056] When the relative density is less than 93%, the piezoelectric property and/or mechanical quality factor may not be satisfactory and the mechanical strength may be degraded.
[0057] The main component of the piezoelectric material used in the piezoelectric element has x and y satisfying 0.125 < x < 0.175 and 0.055 < y < 0.090, respectively, and the Mn content is 0.02 parts by weight or more and 0.10 parts per weight or less with respect to 100 parts by weight of metal oxide.
[0058] A piezoelectric element that uses a piezoelectric material within this compositional range is particularly suitable for a displacement actuator (a.k.a., soft device), such as an optical pickup actuator or a liquid discharge head. When x indicating the molar ratio of Ca is less than 0.125, durability can be degraded. When x is greater than 0.175, the piezoelectric strain constant can be decreased. Preferably 0.140 < x < 0.175. When y indicating the molar ratio of Zr is less than 0.055, the piezoelectric strain constant can be decreased. When y is greater than 0.09, the Curie temperature will decrease and so the device's operating temperature range may be narrowed. Preferably 0.055 < y < 0.075. When the Mn content is less than 0.02 parts by weight, the polarization treatment may not be carried out satisfactorily. At an Mn content greater than 0.10 parts by weight, the piezoelectric strain constant can be decreased. A preferable range for a is 1,000 < a < 1,005.
[0059] The main component of the piezoelectric material used in the piezoelectric element preferably has x and y respectively satisfying 0.155 < x < 0.300 and 0.041 < y < 0.069. The Mn content is preferably 0.12 parts by weight or more and 0.40 parts by weight or less on a metal basis relative to 100 parts by weight of the main metal oxide component.
[0060] A piezoelectric element using piezoelectric material within that compositional range is particularly suitable for resonance devices (rigid devices) such as piezoelectric sensors, piezoelectric transformers, and ultrasonic motors. When x indicating the molar ratio of Ca is less than 0.155, the mechanical quality factor can be decreased. When x is greater than 0.300, the piezoelectric strain constant can be degraded. Preferably 0.160 < x < 0.300. When y indicating the molar ratio of Zr is less than 0.041, the piezoelectric strain constant can be decreased. When y is greater than 0.069, the device operating temperature range may be narrowed. Preferably 0.045 < y < 0.069. When the Mn content is less than 0.12 parts by weight, the mechanical quality factor can be decreased and the power consumption during device operation at a resonant frequency can increase. When the Mn content is greater than 0.40 parts by weight, the piezoelectric strain constant may be lowered and a higher voltage may be required to drive the device. Preferably, the Mn content is 0.20 parts by weight or more and 0.40 parts by weight or less. A preferable range for a is 1.004 < a < 1.009.
[0061] A method for producing the piezoelectric material used in the piezoelectric element is not particularly limited. In order to produce a piezoelectric ceramic, solid powders such as oxides, carbonate salts, nitrate salts, oxalate salts, and the like, containing the elements that make up the ceramic, can be sintered at normal pressure, which is a process typical. The raw materials are metal compounds, such as a Ba compound, a Ca compound, a Ti compound, a Zr compound, and a Mn compound.
[0062] Examples of the Ba compound that can be used include barium oxide, barium carbonate, barium oxalate, barium acetate, barium nitrate, barium titanate, barium zirconate, and barium zirconate titanate.
[0063] Examples of the Ca compound that can be used include calcium oxide, calcium carbonate, calcium oxalate, calcium acetate, calcium titanate, and calcium zirconate.
[0064] Examples of the Ti compound that can be used include titanium oxide, barium titanate, barium zirconate titanate, and calcium titanate.
[0065] Examples of the Zr compound that can be used include zirconium oxide, barium zirconate, barium zirconate titanate, and calcium zirconate.
[0066] Examples of the Mn compound that can be used include manganese carbonate, manganese oxide, manganese dioxide, manganese acetate, and trimanganese tetroxide.
[0067] The raw materials for adjusting the a molar ratio, that is, the molar amount of Ba and Ca at the A sites to the molar amount of Ti and Zr at the B sites of the piezoelectric ceramic used in the piezoelectric element are not particularly limited. The same effect can be obtained from a Ba compound, a Ca compound, a Ti compound, and a Zr compound.
[0068] The method for granulating the raw material powders of the piezoelectric ceramic used in the piezoelectric element is not particularly limited. From the standpoint of uniformity of particle diameter of the resulting powder, a spray dry method can be employed.
[0069] Examples of the binder used in granulation include polyvinyl alcohol (PVA), polyvinyl butyral (PVB), and acrylic resins. The amount of binder added is preferably 1 to 10 parts by weight and more preferably 2 to 5 parts by weight from the viewpoint of increasing the density of a compact.
[0070] The method for sintering the piezoelectric ceramic used in the piezoelectric element is not particularly limited. Sintering can be conducted with an electric oven or a gas oven or by an electric heating method, a microwave sintering method, a millimeter microwave sintering method, or hot isostatic pressing (HIP). Sintering using an electric or gas furnace can be conducted in a continuous furnace or a batch production furnace.
[0071] The sintering temperature of ceramics in the sintering method described above is not particularly limited. The sintering temperature can be a temperature that allows the compounds to react and undergo sufficient crystal growth. The sintering temperature is preferably 1200°C or higher and 1550°C or lower and more preferably 1300°C or higher and 1480°C or lower, from the viewpoint of producing the grain diameter of the ceramic to be within the range of 1 µm to 10 µm. A piezoelectric ceramic sintered within this temperature range exhibits a good piezoelectric property.
[0072] In order to stabilize the properties of the piezoelectric ceramic obtained by sintering while obtaining high reproducibility, the sintering temperature can be kept constant within the range described above and the sintering can be conducted for 2 to 24 hours. A two-stage sintering method can be employed, but rapid temperature variations are not desirable from a productivity standpoint.
[0073] Piezoelectric ceramic can be heat treated at a temperature of 1000°C or higher after being polished. When a piezoelectric ceramic is mechanically polished, a residual stress occurs within the piezoelectric ceramic. This residual voltage can be relaxed by heat treatment at 1000°C or higher and the piezoelectric property of piezoelectric ceramics can be further improved. Heat treatment also has an effect of eliminating raw material powders, such as barium carbonate, precipitated in borderline portions of grain. The amount of time for the heat treatment is not particularly limited, but it can be 1 hour or more long.
[0074] The piezoelectric element may have polarization axes oriented in a particular direction. When the polarization axes are oriented in a particular direction, the piezoelectric constant of the piezoelectric element is increased. The polarization method for the piezoelectric element is not particularly limited. The polarizing treatment can be carried out in air or in silicone oil. The temperature during polarization can be 60°C to 100°C, but the optimal conditions slightly vary depending on the composition of the piezoelectric ceramic that makes up the device. The electric field applied to conduct the polarization treatment can be 800 V/mm to 2.0 kV/mm.
[0075] The piezoelectric constant and mechanical quality factor of the piezoelectric element can be calculated from a resonant frequency and an antiresonant frequency measured with a commercially available impedance analyzer on the basis of the Electronic Materials Manufacturers Association of Standards of the Japan (Electronic Materials Manufacturers Association of Japan Standard) (EMAS-6100). This method is hereinafter referred to as a resonance - antiresonance method.
[0076] The multilayer piezoelectric element
[0077] The piezoelectric elements constituted by multiple layers according to embodiments of the invention will now be described.
[0078] A multilayer piezoelectric element according to a modality is constituted by alternating stacking of layers of piezoelectric material and electrodes (including one or more internal electrodes). The piezoelectric material layers are each composed of a piezoelectric material that contains a perovskite-type metal oxide represented by the general formula (1) below as a major component and manganese (Mn) incorporated in the perovskite-type metal oxide perovskite: (Bai-xCax) to (Tii-yZry) O3 (where 1.00 < a < 1.01, 0.02 < x < 0.30, 0.020 < y < 0.095, and y < x) (1)
[0079] The Mn content is 0.02 parts by weight or more and 0.40 parts by weight or less on a metal basis relative to 100 parts by weight of metal oxide.
[0080] Figures 5A and 5B are each a cross-sectional view showing a structure of a multilayer piezoelectric element according to an embodiment. The multilayer piezoelectric element includes layers of piezoelectric material and electrodes (including one or more inner electrodes) that are stacked alternately. The piezoelectric material layers are composed of the aforementioned piezoelectric material. Electrodes can include internal electrodes and external electrodes.
[0081] Figure 5A shows a multilayer piezoelectric element according to an embodiment. The multilayer piezoelectric element includes two layers of piezoelectric material 54 and a layer of an inner electrode 55 alternately stacked, and the resulting stack is sandwiched between a first electrode 51 and a second electrode 53. The number of layers of the layers of piezoelectric material and the number of inner electrode layers can be increased, as shown in figure 5B, and are not particularly limited.
[0082] Figure 5B shows a piezoelectric element consisting of multiple layers according to another modality. The multi-layer piezoelectric element includes nine layers of layers of piezoelectric material 504 and eight layers of inner electrodes 505 which are stacked alternately, and the resulting stack is sandwiched between a first electrode 501 and a second electrode 503. An outer electrode 506a and an outer electrode 506b for short circuiting the alternately stacked inner electrodes are disposed on the side surfaces of the stack.
[0083] The inner electrodes 55 and 505 and the outer electrodes 506a and 506b may have a different size and shape than the piezoelectric material layers 54 and 504 and may be divided into a plurality of segments.
[0084] Each of the inner electrodes 55 and 505 and the outer electrodes 506a and 506b is constituted by a conductive layer that has a thickness of about 5 nm to 2000 nm. The material for this is not particularly limited and any material that is usually used in piezoelectric elements can be used. Examples of such a material include metals such as Ti, Pt, Ta, Ir, Sr, In, Sn, Au, Al, Fe, Cr, Ni, Pd, Ag, and Cu and compounds thereof. Each of the inner electrodes 55 and 505 and the outer electrodes 506a and 506b can be composed of one of these materials or a mixture or an alloy of two or more of these materials, or it can be constituted by a multilayer structure prepared by stacking two or more of these materials. The electrodes can be composed of materials different from each other. Inner electrodes 55 and 505 can be composed primarily of Ni as Ni is a low cost electrode material.
[0085] As shown in figure 5B, the electrodes including the internal electrodes 505 can be short-circuited from one another to produce matching drive voltage phases. For example, inner electrodes 505, first electrode 501, and second electrode 503 can be short-circuited in an alternate manner. The form of short-circuiting between the electrodes is not particularly limited. Electrodes and/or metallic wires can be formed on the side surfaces of a multilayer piezoelectric element to conduct short circuiting, or through holes that penetrate the layers of piezoelectric material 504, can be formed and filled with a shape conductive material to short circuit the electrodes.
[0086] The method for producing a multilayer piezoelectric element is not particularly limited. One example is a method that includes a step (A) of preparing sludge by dispersing a metal compound powder containing at least Ba, Ca, Ti, Zr, and Mn, a step (B) of obtaining a compact by placing the slurry on a substrate, a step (C) of forming an electrode on the compact, and a step (D) of obtaining a multilayer piezoelectric element by sintering the compact on which the electrode was formed.
[0087] In this description, a "powder" refers to a group of solid particles. A powder can be a group of particles each containing Ba, Ca, Ti, Zr, and Mn or a group of a plurality of particle types containing different elements.
[0088] Examples of the metal compound powder used in step (A) include a Ba compound, a Ca compound, a Ti compound, a Zr compound, and a Mn compound. Examples of the Ba compound that can be used include barium oxide, barium carbonate, barium oxalate, barium acetate, barium nitrate, barium titanate, barium zirconate, and barium zirconate titanate.
[0089] Examples of the Ca compound that can be used include calcium oxide, calcium carbonate, calcium oxalate, calcium acetate, calcium titanate, calcium zirconate, and calcium titanate zirconate.
[0090] Examples of the Ti compound that can be used include titanium oxide, barium titanate, barium zirconate titanate, and calcium titanate.
[0091] Examples of the Zr compound that can be used include zirconium oxide, barium zirconate, barium zirconate titanate, and calcium zirconate.
[0092] Examples of the Mn compound that can be used include manganese carbonate, manganese oxide, manganese dioxide, manganese acetate, and trimanganese tetroxide.
[0093] An example of a method for preparing a slurry in step (A) is as follows. To a metal compound powder, a solvent having a weight 1.6 to 1.7 greater than that of the metal compound powder is added, followed by mixing. Examples of the solvent that can be used include toluene, ethanol, a mixed solvent of toluene-ethanol, n-butyl acetate, and water. The resulting mixture is mixed in a ball mill for 24 hours and a binder and plasticizer are added to it. Examples of the binder include polyvinyl alcohol (PVA), polyvinyl butyral (PVB), and acrylic resins. When PVB is used as the binder, the binder is weighed so that the weight ratio of solvent to PVB is, for example, 88:12. Examples of the plasticizer include dioctyl sebacate, dioctyl phthalate, and dibutyl phthalate. When dibutyl phthalate is used as the plasticizer, dibutyl phthalate is weighed so that its weight is the same as that of the binder. Then, the resulting mixture is again mixed in a ball mill overnight. The amounts of solvent and binder are adjusted so that the viscosity of the slurry is 300 to 500 mPa's.
[0094] The compact prepared in step (B) is a mixture in sheet form of the metal compound powder, the binder, and the plasticizer. An example of a method for preparing the compact in step (B) is a sheet forming method. A doctor blade method can be employed in the sheet forming method. A doctor blade method is a method that includes applying mud to the substrate through the use of a doctor blade and drying the applied mud to form a sheet-shaped compact. A polyethylene terephthalate (PET) film can be used as the substrate, for example. A surface of a PET film, on which the slurry is to be placed, can be coated with a fluorine coating in advance to facilitate separation of the compact. Mud can be dried by air or hot air. The thickness of the compact is not particularly limited and can be adjusted according to the thickness of the multilayer piezoelectric element. The thickness of the compact can be increased by increasing the viscosity of the slurry, for example.
[0095] The method for producing the electrodes, for example, inner electrodes 505 and outer electrodes 506a and 506b, in step (C), is not particularly limited. The electrodes can be formed by baking a metal slurry, or by a method such as sputter metallization, vapor deposition, or printing. The thickness and pitch of the layers of piezoelectric material 504 can be decreased to reduce the drive voltage. In such a case, a process of forming a pile including precursors of the piezoelectric material layers 504 and inner electrodes 505 and then baking the resulting pile is selected. When this process is selected, the material of the inner electrodes 505 is desirably a material that does not undergo changes in shape or deterioration in conductivity at a temperature necessary to sinter the layers of piezoelectric material 504. Metals such as Ag, Pd, Au, Cu , and Ni, which have lower melting points and are less expensive than Pt, and alloys of such metals can be used to form electrodes, such as the inner electrodes 505 and the outer electrodes 506a and 506b. Alternatively, the external electrodes 506a and 506b can be formed after the pile has been cooked and, in such a case, can be composed of Al or a carbon-based electrode material in addition to Ag, Pd, Cu, or Ni.
[0096] The electrodes can be formed by a screen printing method. One method of screen printing involves applying a metal paste to a compact onto a substrate through a cross-linked plate using a spatula. A lattice mesh is formed on at least part of the lattice plate. Thus, the metal paste is applied to the compact only in the portions where the reticulated mesh is formed. The lattice mesh on the lattice plate may have a pattern formed thereon. The pattern is transferred to the compact using the metal paste to form a patterned electrode over the compact.
[0097] After the electrode is formed in step (C) and the compact with the electrode is separated from the substrate, one or a plurality of layers of the compacts are bonded by compression. Examples of the compression bonding method include uniaxial pressing, cold isostatic pressing, and hot isostatic pressing. Compression bonding can be conducted by hot isostatic pressing, as pressure can be uniformly and isostatically applied to the compacts. Compression bonding can be conducted by heating to a temperature close to the glass transition temperature of the binder for satisfactory bonding. Two or more of the compacts can be stacked and compressed together until a desired thickness is achieved. For example, 10 to 100 layers of compacts can be stacked and thermally bonded by compression for 10 seconds to 10 minutes by applying a pressure of 10 to 60 MPa in a stacking direction at 50°C to 80°C to form a structure consisting of multiple layers. Alignment marks can be affixed to the electrodes so that a plurality of layers of compacts can be precisely aligned and stacked. Alternatively, accurate stacking can be conducted by forming through holes for alignment in compacts.
[0098] Although the sintering temperature of the compact in step (D) is not particularly limited, the sintering temperature can be a temperature at which the compounds can react and sufficient crystal growth occurs. The sintering temperature is preferably 1200°C or higher and 1550°C or lower and more preferably 1300°C or higher and 1480°C or lower to adjust the ceramic grain diameter to be within a range of 1 µm to 10 µm. A multilayer piezoelectric element, sintered within this temperature range, exhibits a good piezoelectric property.
[0099] When a material mainly composed of Ni is used in the electrodes in step (C), step (D) can be conducted in an oven capable of atmospheric ignition. The binder is calcined and removed at a temperature of 200°C to 600°C in an ambient atmosphere and then the compact is sintered at a temperature of 1200°C to 1550°C in a reducing atmosphere. A reducing atmosphere refers to an atmosphere primarily composed of a gas mixed with hydrogen (H2) and nitrogen (N2). The volume ratio between hydrogen and nitrogen can be H2:N2 = 1:99 to 10:90. Mixed gas may contain oxygen. The oxygen concentration is 10-12 Pa or more and 10-4 Pa or less and preferably 10-8 Pa or more and 10-5 Pa or less. The oxygen concentration can be measured with a zirconia type oxygen sensor. Once Ni electrodes are used, the multilayer piezoelectric element can be produced at a low cost. After combustion in the reducing atmosphere, the compact can be cooled to 600°C and the atmosphere can be modified to the ambient atmosphere (oxidizing atmosphere) to conduct an oxidation treatment. After the compact is discharged from the combustion furnace, a conductive paste is applied to a side surface of the compact, where the ends of the inner electrodes are exposed, and dried to form an outer electrode. Liquid discharge head
[00100] A liquid discharge head according to an embodiment of the present invention includes at least one discharge port in communication with a liquid reservoir equipped with a vibration unit that includes a piezoelectric element or the multilayer piezoelectric element.
[00101] Figures 2A and 2B show a structure of a liquid discharge head according to an embodiment of the present invention. As shown in Figures 2A and 2B, the liquid discharge head includes a piezoelectric element 101. The piezoelectric element 101 includes a first electrode 1011, a piezoelectric material 1012, and a second electrode 1013. The piezoelectric material 1012 is provided with patterns, when necessary, as shown in figure 2B.
[00102] Figure 2B is a schematic view of the liquid discharge head. The liquid discharge head includes discharge ports 105, individual liquid reservoirs 102, connection holes 106 connecting individual liquid reservoirs 102 to discharge ports 105, separations 104, a common liquid reservoir 107, a plate of vibration 103, and the piezoelectric element 101. Although the piezoelectric element 101 illustrated in the drawing has a rectangular shape, the shape can be any other shape, such as an elliptical shape, a circular shape, or a rectangular parallelepiped shape. In general, the piezoelectric material 1012 follows the shape of the individual liquid reservoir 102.
[00103] The piezoelectric element 101 and its proximal portion in the liquid discharge head will now be described in detail with reference to figure 2A. Figure 2A is a cross-sectional view of the piezoelectric element shown in Figure 2B, taken in the width direction. Although the cross-sectional shape of the piezoelectric element 101 in the drawing is rectangular, the cross-sectional shape can be any other shape, such as a trapezoidal shape or an inverted trapezoidal shape.
[00104] In the drawing, the first electrode 1011 is used as a bottom electrode and the second electrode 1013 is used as a top electrode. However, the arrangement of the first electrode 1011 and the second electrode 1013 is not limited thereto. For example, the first electrode 1011 can be used as the bottom electrode or the top electrode. The second electrode 1013 can be used as the top electrode or the bottom electrode. An intermediate layer 108 may be present between the vibrating plate 103 and the lower electrode. Such differences in designation are derived from the method of production of the device and the effects of the present invention can be obtained in each case.
[00105] The vibration plate 103 of the liquid discharge head moves in vertical directions as the piezoelectric material 1012 expands and contracts, and applies pressure to the liquid in the individual liquid reservoir 102. As a result, liquid is ejected from discharge hole 105. The liquid discharge head can be used in printers and for the production of electronic devices.
[00106] The thickness of the vibration plate 103 is 1.0 μm or more and 15 μm or less and preferably 1.5 μm or more and 8 μm or less. The material to form the vibrating plate 103 is not particularly limited, but it may be silicon. Silicon constituting the vibrating plate 103 can be doped with boron or phosphorus. The intermediate layer 108 on the vibration plate 103 and the electrode on the intermediate layer 108 may form part of the vibration plate 103. The thickness of the intermediate layer 108 is 5 nm or greater and 300 nm or less and preferably 10 nm or greater and 200 nm or less. The size of the discharge hole 105 is 5 µm or larger and 40 µm or smaller in terms of circular equivalent diameter. The shape of the discharge hole 105 can be circular, star-shaped, rectangular, or triangular, for example. liquid discharge apparatus
[00107] A liquid discharging apparatus according to an embodiment of the present invention will now be described. The liquid discharge apparatus includes the liquid discharge head described above.
[00108] An example of the liquid discharge apparatus is an ink jet recording apparatus, shown in figures 6 and 7. Figure 7 shows the state in which the outer boxes 882 to 885 and 887 are removed from a liquid discharge apparatus (ink jet recording apparatus) 881 shown in Figure 6. The ink jet recording apparatus 881 includes an automatic feed unit 897 configured to automatically feed a sheet of recording paper, i.e., a recording medium, into a main body 896. The ink jet recording apparatus 881 also includes a transport unit 899 which guides the recording sheet fed from the automatic feed unit 897 to a particular recording position. and to a discharge slot 898 from the recording position, a recording unit 891 configured to conduct recording on the transferred recording sheet to the recording position, and a recovery unit 890 with Figured to conduct a recovery process on the recording unit 891. The recording unit 891 has a carriage 892 which houses the liquid discharge head and which moves on a rail in an alternating manner.
[00109] When an electrical signal is fed to this inkjet recording apparatus from a computer, the carriage 892 moves on the rail and a drive voltage is applied to the electrodes that sandwich the piezoelectric material so that the piezoelectric material undergoes deformation. This deformation of the piezoelectric material pressurizes the individual liquid reservoir 102 through the vibrating plate 103 and causes ink to be ejected from the discharge port 105, thus realizing the printing.
[00110] This liquid discharge apparatus can uniformly eject liquid at a high velocity and is small in size. Although an example of a printer is described above, the liquid discharging apparatus can be used in industrial liquid discharging apparatus and drawing apparatus configured to draw pictures, characters, etc., onto media, in addition to printing apparatus, such as facsimile machines, multifunction devices, and inkjet recording devices. ultrasonic engine
[00111] An ultrasonic motor according to an embodiment of the present invention includes at least one movable element that contacts a vibrating element equipped with a piezoelectric material or the multilayer piezoelectric element.
[00112] Figures 3A and 3B are each a schematic view showing a structure of an ultrasonic engine according to an embodiment of the present invention. Figure 3A shows an ultrasonic motor that includes a piezoelectric element that has a single-layer structure. The ultrasonic motor includes a vibrator 201, a rotor 202 that pressure contacts a sliding surface of the vibrator 201 due to the compressive force of a compression spring (not shown in the drawing), and an output shaft 203 integral with the rotor 202 The vibrator 201 consists of, for example, an elastic ring of metal 2011, a piezoelectric element 2012, and an organic adhesive 2013 (epoxy-based adhesive or cyanoacrylate-based adhesive, for example) that glues the piezoelectric element 2012 to the 2011 elastic ring. The 2012 piezoelectric element is composed of a piezoelectric material sandwiched between a first electrode and a second electrode, which are not shown in the drawing.
[00113] When two phases of AC voltage, which are different from each other by π/2, are applied to the piezoelectric element 2012, the bending displacement wave is generated in the vibrator 201 and each of the points on the sliding surface of the vibrator 201 undergoes elliptical movement. When rotor 202 is in pressure contact with the sliding surface of vibrator 201, vibrator 201 receives frictional force from vibrator 201 and rotates in a direction opposite to that of the bending displacement wave. An object to be driven, which is not shown in the drawing, is attached to the output shaft 203 and is driven by the rotating force of the rotor 202. When voltage is applied to the piezoelectric material, the piezoelectric material expands and contracts due to the effect piezoelectric cross section. When an elastic element, such as a metal element, is in contact with the piezoelectric element, the elastic element is flexed as the piezoelectric material expands and contracts. The ultrasonic motor described here is of a type that operates on this principle.
[00114] Figure 3B shows an example of an ultrasonic motor that includes a piezoelectric element that has a structure consisting of multiple layers. A vibrator 204 includes a cylindrical metal elastic element 2041 and a multilayer piezoelectric element 2042 provided on the metal elastic element 2041. The multilayer piezoelectric element 2042 is comprised of a plurality of layers of piezoelectric materials, although this is not shown in the drawing. A first electrode and a second electrode are disposed on the outer surfaces of the stack and inner electrodes are provided within the stack. The elastic metal element 2041 is bolted to sandwich the multilayer piezoelectric element 2042 to thereby constitute the vibrator 204.
[00115] The application of different phases of AC voltage to the multilayer piezoelectric element 2042 causes the vibrator 204 to excite two vibrations orthogonal to each other. These two vibrations combine to form a circular vibration that drives the tip of the vibrator 204. An annular groove is formed in the top of the vibrator 204 to increase the vibration displacement for the drive. A rotor 205 pressure contacts the vibrator 204 due to a pressurizing spring 206 and receives frictional force for the drive. The rotor 205 is rotatably supported on bearings. optical device
[00116] In the following, an optical apparatus according to an embodiment of the present invention is described. The optical apparatus includes an ultrasonic motor in a drive unit.
[00117] Figures 8A and 8B are each a cross-sectional view of a related part of a replaceable lens cylinder of a single-lens Reflex type camera, which is an example of an imaging apparatus according to an embodiment of the present invention. Figure 9 is an exploded perspective view of the replaceable lens barrel.
[00118] With reference to figures 8A, 8B, and 9, a fixed cylinder 712, linear guide cylinder 713, and a lens group front cylinder 714 are attached to a bracket 711 that can be detached from, and can be posted to, a camera. These are fixed elements of the replaceable lens barrel.
[00119] A linear guide groove 713a extending in an optical axis direction is formed in the linear guide cylinder 713 to guide a focusing lens 702. A cam roller 717a and a cam roller 717b projecting in one direction outer radial are secured with a shaft screw 718 to a lens group rear cylinder 716 which retains the focusing lens 702. Cam roller 717a is fitted in linear guide groove 713a.
[00120] A cam ring 715 is rotatably fitted to the inner periphery of the linear guide cylinder 713. Relative movements between the linear guide cylinder 713 and the cam ring 715 in the direction of the optical axis are inhibited, since a roller 719 secured to cam ring 715 is fitted in an annular groove 713b of linear guide cylinder 713. A cam groove 715a for focus lens 702 is formed in cam ring 715. Cam roller 717b is fitted in cam groove 715a.
[00121] A rotation drive ring 720 is provided on the outer peripheral side of the fixed cylinder 712. The rotation drive ring 720 is retained by a ball raceway 727 so that it can rotate in a particular position relative to the cylinder fixed 712. A roller 722 is rotatably retained by a shaft 720f which extends radially from the rotating drive ring 720, and a large diameter portion 722a of roller 722 is in contact with a side end surface. of support 724b of a manual focus ring 724. A small diameter portion 722b of the roller 722 is in contact with a joint element 729. Six rollers 722, equally spaced, are arranged on the outer periphery of the rotation drive ring 720 and each roller is configured to have the relationship described above.
[00122] A low friction plate (washer element) 733 is arranged over the radially inner portion of the manual focus ring 724. The low friction plate 733 is interposed between a support side end surface 712a of the fixed cylinder 712 and a front side end surface 724a of the manual focus ring 724. The radially outer surface of the low friction plate 733 is ring-shaped and is fitted to an inner radial portion 724c of the manual focus ring 724. The radial portion inner 724c of manual focus ring 724 is fitted to an outer radial portion 712b of fixed cylinder 712. Low friction plate 733 reduces friction in a friction ring mechanism, in which manual focus ring 724 is rotated relative to to the fixed cylinder 712 about the optical axis.
[00123] The large diameter portion 722a of roller 722 and a support side end surface 724b of the manual focus ring 724 contact each other under pressure by being pressed by a wave washer 726 which presses an ultrasonic motor 725 in the direction to the front side of the lens. The force of the wave washer 726 which presses the ultrasonic motor 725 towards the front side of the lens also causes the small diameter portion 722b of the roller 722 and the gasket element 729 to contact each other through a suitable degree of compression. Wave washer 726 is constrained against movement in the support direction by a washer 732 mounted bayonet-shaped on fixed cylinder 712. Spring force (tension force) generated by wave washer 726 is transmitted to ultrasonic motor 725 and to the roller 722 and serves as the thrust force of the manual focus ring 724 against the end surface of the support side 712a of the fixed cylinder 712. In other words, the manual focus ring 724 is installed while being tensioned against the surface of end of support side 712a of fixed cylinder 712 through low friction plate 733.
[00124] Consequently, when the ultrasonic motor 725 is driven and rotated with respect to the fixed cylinder 712 by a control unit, not shown in the drawing, the roller 722 rotates around the center of the shaft 720f, because the joint element 729 does frictional contact with the small diameter portion 722b of the roller 722. When the roller 722 rotates about the axis 720f, the rotation drive ring 720 is rotated about the optical axis (autofocus operation).
[00125] When rotational force around the optical axis is applied to the manual focus ring 724 from a manual operation input unit, not shown in the drawing, the roller 722 rotates around the axis 720f, since the end surface of the support side 724b of manual focus ring 724 is in pressing contact with large diameter portion 722a of roller 722. When large diameter portion 722a of roller 722 rotates about shaft 720f, the ring 720 rotation transmission is rotated around the optical axis. The 725 ultrasonic motor is at this time prevented from turning due to the frictional holding force of a 725c rotor and a 725b stator (manual focus operation).
[00126] Two focus switches 728 are installed on the rotation drive ring 720 in positions opposite each other and set in notches 715b on the front end of cam ring 715. When auto focus operation or manual focus operation is driven and the rotational transmission ring 720 is rotated about the optical axis, the rotational force is transmitted to the cam ring 715 through the focus switches 728. When the cam ring 715 is rotated about the optical axis, a lens group rear cylinder 716 inhibited from rotating due to cam roller 717a and linear guide groove 713a moves back and forth along cam groove 715a in cam ring 715 by cam roller 717b. This triggers the focus lens 702 and the focusing operation is conducted.
[00127] Although a replaceable lens cylinder of a single-lens Reflex-type camera has been described as an example of the optical apparatus of the present invention, the range of the optical apparatus is not limited thereto. The optical apparatus can be any type of camera, such as a compact camera, an electronic still camera, or the like, or it can be a portable information terminal equipped with a camera. An optical apparatus having an ultrasonic motor in a drive unit is also within the scope of the present invention. Electronic device
[00128] An electronic apparatus according to an embodiment of the present invention will now be described. An electronic apparatus according to an embodiment includes a piezoelectric acoustic component equipped with a piezoelectric element or the multilayer piezoelectric element. The piezoelectric acoustic component can be a speaker, a microphone, a surface acoustic wave device (SAW), or the like.
[00129] Figure 10 is a perspective view of a digital camera, which is an example of the electronic apparatus according to the present invention, when viewed from the front of a main body 931. An optical device 901, a microphone 914 , a strobe light unit 909, and an auxiliary light unit 916 are installed on the front face of the main body 931. Since the microphone 914 is installed inside the main body, it is indicated by a dashed line. A hole for capturing sound from the outside is formed in front of microphone 914.
[00130] A power button 933, a speaker 912, a zoom lever 932, and a release button 908 to perform the focusing operation are installed on the upper surface of the main body 931. The speaker 912 is integrated inside main body 931 and is indicated by a dashed line. Holes for sound emission are formed in front of speaker 912.
[00131] The piezoelectric acoustic component is used in at least one of microphone 914, speaker 912, and a SAW device.
[00132] Although a digital camera is described as an example of the electronic device of the present invention, the electronic device is not limited thereto and can be any electronic device equipped with a piezoelectric acoustic component, such as a sound reproduction device, a sound recording apparatus, a cell phone, and an information terminal.
[00133] As described above, the modalities of the piezoelectric element and the multilayer piezoelectric element, described above, are suitable for use in a liquid discharge head, a liquid discharge apparatus, an ultrasonic motor, an apparatus optical, and an electronic device.
[00134] When the piezoelectric element or multilayer piezoelectric element of the present invention is used, a liquid discharge head that has a nozzle density and discharge force comparable to or greater than a liquid discharge head that includes an element piezoelectric containing lead may be provided. A liquid discharge apparatus equipped with a liquid discharge head in accordance with an embodiment of the present invention may exhibit discharge force and discharge accuracy comparable to or greater than a liquid discharge apparatus using a liquid discharge head including a piezoelectric element containing lead.
[00135] An ultrasonic motor that uses the piezoelectric element or the multilayer piezoelectric element, according to an embodiment of the present invention, exhibits driving or driving force and durability comparable or superior to an ultrasonic motor that uses a piezoelectric element containing lead . An optical apparatus that uses the ultrasonic motor may exhibit durability and operating accuracy comparable or superior to an optical apparatus that uses an ultrasonic motor that includes a piezoelectric element containing lead. An electronic apparatus that uses a piezoelectric acoustic component equipped with a piezoelectric element or the multilayer piezoelectric element, in accordance with an embodiment of the present invention, exhibits a sound generation property comparable to or superior to that of an electronic apparatus that includes an element piezoelectric containing lead. EXAMPLES
[00136] The present invention will now be described in more detail through the use of Examples which do not limit the scope of the invention.
[00137] A piezoelectric ceramic for use in a piezoelectric element was prepared. Production Example 1
[00138] Barium titanate having an average particle diameter of 100 nm (BT-01 produced by Sakai Chemical Industry Co., Ltd.), calcium titanate having an average particle diameter of 300 nm (CT-03 produced by Sakai Chemical Industry Co., Ltd.), and calcium zirconate having an average particle diameter of 300 nm (CZ-03 produced by Sakai Chemical Industry Co., Ltd.) were weighed so that the ratio was 90.5: 6.5:3.0 on a molar basis. In order to adjust the a molar ratio of Ba and Ca at sites A to Ti and Zr at sites B, 0.008 mol of barium oxalate was added. The resulting mixture was dry blended in a ball mill for 24 hours. To the resulting mixture, 0.08 parts by weight of manganese(II) acetate on a manganese metal base and 3 parts by weight of a PVA binder relative to the mixed powder were made to adhere to the surfaces of the mixed powder by through the use of a spray dryer in order to granulate the mixed powder.
[00139] The granulated powder was loaded into a mold and compressed under 200 MPa forming pressure with a compression molding machine to prepare a compact in disc shape. The compact can be further compressed through the use of a cold compression molding machine.
[00140] The compact was placed in an electric oven and sintered in an air atmosphere for a total of 24 hours, during which a maximum temperature of 1400°C was maintained for 5 hours.
[00141] The mean circular equivalent diameter and the relative density of crystal grains that constituted the resulting ceramic were evaluated. The mean circular equivalent diameter was 6.2 μm and the relative density was 94.9%. A polarizing microscope was mainly used to observe crystal grains. The diameter of small crystal grains was determined using a scanning electron microscope (SEM). The mean circular equivalent diameter was calculated based on the observation results. Relative density was evaluated using the Archimedes method.
[00142] The ceramic was polished to a thickness of 0.5 mm and the crystal structure of the ceramic was analyzed by X-ray diffraction. As a result, only peaks attributable to a perovskite-like structure were observed.
[00143] The composition of the ceramic was analyzed by X-ray fluorescence analysis. The results found that 0.08 parts by weight of Mn were incorporated into a composition expressed by a chemical formula,
[00144] (Ba0.905Ca0.095)1.002 (Ti0.97 Zr0.03) O3. This means that the composition prepared by weighing corresponds to the composition after sintering. The contents of the elements other than Ba, Ca, Ti, Zr, and Mn were below the detection limits, ie, less than 0.1 parts by weight.
[00145] The crystal grains were observed again. However, the mean circular equivalent diameter was not very different between before and after polishing. Production Examples 2 to 52, 72, and 73
[00146] Barium titanate having an average particle diameter of 100 nm (BT-01 produced by Sakai Chemical Industry Co., Ltd.), calcium titanate having an average particle diameter of 300 nm (CT-03 produced by Sakai Chemical Industry Co., Ltd.), and calcium zirconate having an average particle diameter of 300 nm (CZ-03 produced by Sakai Chemical Industry Co., Ltd.) were weighed so that the ratio on a molar basis was like shown in Tables 1-1 and 1-2. In order to adjust the a molar ratio of Ba and Ca at sites A to Ti and Zr at sites B, barium oxalate in an amount indicated in Tables 1-1 and 1-2 was weighed. These powders were dry blended in a ball mill for 24 hours. In Example 48, 0.8 parts by weight of Si in an oxide base was added as an auxiliary component. In Example 52, a total of 1.0 parts by weight of Si and Cu on an oxide basis were added as auxiliary components. To the resulting mixture, manganese(II) acetate in an amount in a manganese metal base shown in Tables 1-1 and 1-2 and 3 parts by weight of a PVA binder relative to the mixed powder were made to adhere to the surfaces of the mixed powder through the use of a spray dryer in order to granulate the mixed powder.
[00147] The granulated powder was loaded into a mold and compressed under 200 MPa forming pressure with a compression molding machine to prepare a disc-shaped compact. The compact can be further compressed through the use of a cold isostatic compression molding machine.
[00148] The compact was placed in an electric oven and sintered in an air atmosphere for a total of 24 hours, during which a maximum temperature of 1350°C to 1480°C was maintained for 5 hours. The maximum temperature was increased as the amount of Ca was increased.
[00149] The mean circular equivalent diameter and the relative density of crystal grains constituting the resulting ceramic were evaluated. The results are shown in Tables 2-1 and 2-2. A polarizing microscope was mainly used to observe crystal grains. The diameter of small crystal grains was determined using a scanning electron microscope (SEM). The mean circular equivalent diameter was calculated based on the observation results. Relative density was evaluated using the Archimedes method.
[00150] The ceramic was polished to a thickness of 0.5 mm and the crystal structure of the ceramic was analyzed by X-ray diffraction. As a result, only peaks attributable to a perovskite-like structure were observed in all samples.
[00151] The composition of the ceramic was analyzed by X-ray fluorescence analysis. The results are shown in Tables 3-1 and 3-2. In the table, auxiliary components refer to elements other than Ba, Ca, Ti, Zr, and Mn and 0 means the content was below the detection limit. As a result, it was found that the composition prepared by weighing matched the composition after sintering in all samples.
[00152] The crystal grains were observed again. However, the size and condition of the crystal grains were not very different between after sintering and after polishing. Production Examples 53 to 71 for comparison
[00153] The same raw material powders as those in Examples 1 to 52, 72, and 73 and barium zirconate having an average particle diameter of 300 nm (produced by Nippon Chemical Industrial Co., Ltd.) were weighed from so the molar ratio was as shown in Tables 1-1 and 1-2. Each mixture was dry blended in a ball mill for 24 hours. In Production Example 65, Y and V in a total amount of 2.1 parts by weight on an oxide basis were added. To the resulting mixture, manganese(II) acetate in an amount in a manganese metal base indicated in Tables 1-1 and 1-2 and 3 parts by weight of a PVA binder relative to the mixed powder were made to adhere to the surfaces of the mixed powders through the use of a spray dryer in order to granulate the mixed powder.
[00154] A ceramic was prepared under the same conditions as in Examples 2 to 52, 72, and 73 by using each of the resulting granulated powders. The mean circular equivalent diameter and the relative density of crystal grains constituting the ceramic were evaluated. The results are shown in Tables 2-1 and 2-2. Evaluation of crystal grains and relative density was conducted as in Examples 1 to 52, 72, and 73.
[00155] Each resulting ceramic was polished to a thickness of 0.5 mm and the crystal structure of the ceramic was analyzed by X-ray diffraction. As a result, only peaks attributable to a perovskite-like structure were observed in all samples.
[00156] The composition of the ceramic was analyzed by X-ray fluorescence analysis. The results are shown in Tables 3-1 and 3-2. As a result, it was found that the composition prepared by weighing matched the composition after sintering in all samples.
[00157] The relationship between x and y in the piezoelectric materials of Production Examples 1 to 73 is shown in the graph of Figure 1. In the figure, the range marked by a dashed line indicates the range of x and y of the general formula (1) representing the oxide metal of the perovskite type described in the modality.
[00158] [ Table 1 - 1 ]



[00159] [ Table 1 - 2 ]



[00160] [ Table 2 - 1 ]


[00161] [Table 2 - 2]


[00162] [Table 3 - 1]




[00163] [ Table 3 - 2 ]


Piezoelectric element preparation and static characteristics evaluation Examples 1 to 54
[00164] The piezoelectric elements of Examples 1 to 54 were manufactured using ceramics from Production Examples 1 to 52, 72, and 73.
[00165] A gold electrode having a thickness of 400 nm was formed on both sides of the disk-shaped ceramic, described above by CC Sputter Metallization. A titanium film acting as an adhesive layer and having a thickness of 30 nm was formed between the electrode and the ceramic. The ceramic with the electrodes was cut to form a strip-shaped piezoelectric element of size 10 mm x 2.5 mm x 0.5 mm.
[00166] The piezoelectric element was placed on a hot plate having a surface adjusted to 60° C to 100° C and an electric field of 1 kV/mm was applied to the piezoelectric element for 30 minutes to conduct a polarization treatment.
[00167] The static characteristics of the piezoelectric element, that is, the Curie temperature, the dielectric loss, the piezoelectric constant d31, and the mechanical quality factor (Qm) of the polarized piezoelectric element were evaluated. The results are shown in Tables 4-1 and 4-2. The mechanical quality factor is shown in Table 6. The Curie temperature was determined from the temperature at which the dielectric constant measured under the application of a 1 kHz AC micro field, while the measurement temperature variation was maximum. Dielectric loss was also measured simultaneously. The piezoelectric constant d31 was determined by a resonance-antiresonance method and the absolute value is indicated in the table.
[00168] Tables 4-1 and 4-2 also show the amounts of Ba and Ca on a molar basis and the molar ratio of Ti/Zr/Mn. In the table, "X" indicates that the assessment could not be conducted.
[00169] [Table 4 - 1]




[00170] [ Table 4 - 2 ]



[00171] All samples in the Examples exhibited a piezoelectric constant d31 of 55 [C/N] or greater and a dielectric loss of 0.4% or less. Although not shown in the tables, the piezoelectric constant d33 was also measured based on the Berlincourt method principle and was 110 [C/N] or higher in all samples.
[00172] Comparison was made between Examples 10 and 11, between Examples 12 and 13, between Examples 19 and 20, and between Examples 21 and 22, where x was 0.125 < x < 0.175 and y was 0.055 < y < 0.090. Although x, y, and Mn content were the same in all combinations, Examples 11, 13, 19, and 21 having a lower a value exhibited higher piezoelectric constants and dielectric losses. In Examples 11, 13, 19, and 21, the ratio of the amounts of Ba and Ca to the amounts of Ti, Zr, and Mn on a molar basis was 0.996 or greater and 0.999 or less.
[00173] Comparison was made between Examples 28 and 29, between Examples 30 and 31, between Examples 38 and 39, and between Examples 40 and 41, where x was 0.155 < x < 0.300 and y was 0.041 < y < 0.069. Although x, y, and Mn content were the same in all combinations, Examples 29, 31, 39, and 41 having a lower a value exhibited higher piezoelectric constants and dielectric losses. In Examples 29, 31, 39, and 41, the ratio of the amounts of Ba and Ca to the amounts of Ti, Zr, and Mn on a molar basis was 0.993 or greater and 0.998 or less.
[00174] Similar characteristics were observed in all Examples when the gold electrodes were replaced by electrodes prepared by baking a silver paste. Comparative Examples 1 to 19
[00175] The piezoelectric elements of Comparative Examples 1 to 19 were manufactured using the ceramics of Production Examples 53 to 71. Fabrication and evaluation of the devices was conducted as in Examples 1 to 54.
[00176] In Comparative Examples 1 and 15, the dielectric loss was high, ie, 0.9% to 1.1%, since Mn was not contained. In Comparative Examples 3, 5, 7, and 9, the piezoelectric constant d31 was low, that is, 41 [C/N] or less, since Zr was not contained. In Comparative Examples 4, 6, 8, and 10, the Curie temperature was low, ie, 60°C, since the Zr content was as high as 15%, and the temperature range in which the piezoelectric element can be used has been narrowed. In Comparative Example 11, sintering did not progress sufficiently due to a high Ca content, ie 32% (x = 0.32), and grain growth was also insufficient. Thus, the piezoelectric constant was low and the dielectric loss was high. In Comparative Example 12, the value of a was as low as 0.980 and abnormal grain growth, i.e. grain growth larger than 30 µm occurred, and static characteristics other than the Curie temperature could not be evaluated. The average circular equivalent diameter of crystal grains constituting a piezoelectric material used in the sample of Comparative Example 12 was significantly greater than the thickness (0.5 mm = 500 μm) of the strip-shaped piezoelectric element, and thus the piezoelectric material cleaved easily and the device exhibited poor mechanical strength. In Comparative Example 13, a total of 2.1 parts by weight of Y and V were contained as the auxiliary components and thus the piezoelectric constant d31 was as low as 36 [C/N]. In Comparative Example 14, the a value was as large as 1.030 and the grain growth was insufficient due to insufficient sintering. Thus, the piezoelectric constant d31 was as low as 20 [C/N] and the dielectric loss was as high as 0.9%. In Comparative Example 16, the Mn content was as high as 0.45 parts by weight and thus the piezoelectric constant was low, although the dielectric loss was low. In Comparative Example 17, the mean circular grain equivalent diameter was less than 1 µm, the piezoelectric constant was low, and the dielectric loss was high. In Comparative Example 18, abnormal grain growth, growing to a value greater than 100 µm in terms of mean circular grain equivalent diameter, was observed, and thus static characteristics other than the Curie temperature could not be evaluated for the same reason than the sample from Comparative Example 12. In Comparative Example 19, in which the relative density was less than 93%, the piezoelectric constant was low and the dielectric loss was high. Note that the static characteristics of Comparative Example 2 were comparable to those of the Examples samples. In Comparative Example 2, x is 0.05 and y is 0.95, which are approximately the same level as the samples in the Examples; however, the difference from the Examples is that y is greater than x. Evaluation of the dynamic characteristics of the piezoelectric element
[00177] The dynamic characteristics of the piezoelectric elements were evaluated. In particular, rates of change in the piezoelectric constant when voltage was applied for 100 hours under the following conditions and power consumption were measured.
[00178] The dynamic characteristics of Examples 8 to 14, 18 to 22, 25, and 26 and Comparative Examples 1, 4, and 19 were evaluated. The piezoelectric constant d31 after an AC voltage of 100 V, 110 kHz, far enough from the resonant frequency of the strip-shaped device to have been applied to a strip-shaped piezoelectric element for 100 hours, was evaluated and the rate of change was calculated. The rate of change in the piezoelectric constant between before and after voltage application is summarized in Table 5.
[00179] [Table 5]

[00180] While the rate of change in piezoelectric property was 5% or less in all samples of Examples, a rate of change of 10% or more was observed in all samples of Comparative Examples. The cause of this in Comparative Examples 1 and 19 is presumably that the dielectric loss was high and thus the electrical loss that occurred upon application of voltage was large. Considering Comparative Example 4, the Curie temperature was as low as 60°C and thus depolarization presumably occurred due to heat generated from the device under the application of voltage. In other words, a device does not achieve sufficient operating durability unless the Curie temperature is 85°C or higher and the dielectric loss is 0.4% or less.
[00181] Another dynamic characteristic of the piezoelectric element, ie, energy consumption, was evaluated as described below. The mechanical quality factor of Examples 17, 23, 27 to 32, 34, 38 to 42, 45, 46, and 49 to 51 and Comparative Examples 2 and 15 was evaluated by a resonance-antiresonance method. The results are shown in Table 6.
[00182] Then, an AC voltage having a frequency close to the resonant frequency (190 to 230 kHz) was applied to a strip-shaped piezoelectric element, and the relationship between the vibration speed and the energy consumption of the device was evaluated. Vibration velocity was measured with a Doppler vibrometer and energy consumption was measured with an energy meter. Power consumption, observed when the applied voltage and frequency were modified so that the vibration speed was 0.40 m/s, is indicated in Table 6.
[00183] [Table 6]


[00184] The power consumption of all samples of Examples was 20 mW or less, while the power consumption of all samples of Comparative Examples was more than 50 mW. The cause of this is presumably that the mechanical quality factor of Comparative Examples 2 and 15 was as low as 190 or less. The mechanical quality factor is important when the device is driven at a frequency close to the resonant frequency and is desirably 400 or higher. Preparation and evaluation of the multilayer piezoelectric element Example 55
[00185] Barium titanate having an average particle diameter of 100 nm (BT-01 produced by Sakai Chemical Industry Co., Ltd.), calcium titanate having an average particle diameter of 300 nm (CT-03 produced by Sakai Chemical Industry Co., Ltd.), and calcium zirconate having an average particle diameter of 300 nm (CZ-03 produced by Sakai Chemical Industry Co., Ltd.) were weighed so that the ratio was 84.0:10 .1:5.9 on a molar basis. In order to adjust the molar ratio of Ba and Ca at sites A to Ti and Zr at sites B, 0.028 mol of barium oxalate was added. To the resulting mixture, 0.40 parts by weight of manganese(IV) oxide in a manganese metal base and 3 parts by weight of a PVA binder were added and mixed. This mixed powder was formed into a sheet by a scraper blade method to prepare a green sheet having a thickness of 50 µm.
[00186] A conductive paste to form internal electrodes was applied on the green sheet by printing. The conductive paste was a Ni paste. Nine green sheets, onto which the conductive paste was applied, were stacked, and the resulting stack was thermally bonded by pressure.
[00187] The pile thermally bonded by pressure was baked in a tubular oven. Cooking was conducted in air at 300°C to remove the binder, then the atmosphere was changed to a reducing atmosphere (H2:N2 = 2:98, oxygen concentration: 2 x 10-6 Pa), and a temperature of 1380 °C was held for 5 hours. In the cooling process, the oxygen concentration was changed to 30 Pa from 1000°C and below, and cooling was conducted to room temperature.
[00188] A sintered body thus obtained was cut into a 10 mm x 2.5 mm piece. The side surfaces of the part were polished and a pair of external electrodes (first and second electrodes) that alternately short-circuit the internal electrodes was formed on the side surfaces polished by metallization by sputtering Au. As a result, a multilayer piezoelectric element as shown in Figure 3B was manufactured.
[00189] The inner electrodes of the multilayer piezoelectric element were observed. Layers of nickel, which is an electrode material, and layers of piezoelectric material were alternately stacked. The multilayer piezoelectric element was placed on a hot plate having a surface set at 60°C to 100°C and an electric field of 1 kV/mm was applied to the multilayer piezoelectric element on the hot plate for 30 minutes to conduct a polarization treatment.
[00190] The piezoelectric properties of the resulting multilayer piezoelectric element were evaluated. The device had a sufficient insulating property and good piezoelectric properties, comparable to those of Example 54. Comparative Example 20
[00191] A multilayer piezoelectric element was manufactured as in Example 55. However, the composition was the same as that in Production Example 64. The layers of piezoelectric material of the multilayer piezoelectric element were observed. Several crystal grains having a diameter of 20 to 30 µm were observed. Thus, the device was extremely fragile and the piezoelectric properties could not be evaluated. Device Manufacturing and Evaluation
[00192] Liquid discharge head including a piezoelectric element from Example 9
[00193] A liquid discharge head shown in figure 2 was manufactured using a piezoelectric element from Example 9. The ink discharge in response to input electrical signals was confirmed.
[00194] Liquid discharge apparatus including a liquid discharge head including a piezoelectric element of Example 9
[00195] A liquid discharge apparatus shown in Figure 6 was manufactured using a liquid discharge head shown in Figure 2 including a piezoelectric element from Example 9. The discharge of ink onto a recording medium in response to Input electrical signals have been confirmed.
[00196] Ultrasonic motor including a piezoelectric element from Example 31
[00197] An ultrasonic motor shown in Figures 3A and 3B was manufactured using a piezoelectric element from Example 31. It was confirmed that the motor was rotated in response to the applied AC voltage.
[00198] Lens cylinder using an ultrasonic motor that includes a piezoelectric element from Example 31
[00199] An optical apparatus shown in Figure 8 was manufactured using an ultrasonic motor using a piezoelectric element from Example 31. The autofocus operation in response to the applied AC voltage was confirmed.
[00200] Electronic apparatus using a piezoelectric acoustic component including a piezoelectric element from Example 31
[00201] An electronic apparatus shown in Figure 10 was manufactured using a piezoelectric acoustic component including a piezoelectric element from Example 31. The operation of the speaker according to an applied AC voltage was confirmed.
[00202] Liquid discharge head including a multi-layer piezoelectric element from Example 55
[00203] A liquid discharge head shown in Figure 2 was fabricated using the multilayer piezoelectric element from Example 55. The ink discharge in response to input electrical signals was confirmed.
[00204] Liquid discharge apparatus using a liquid discharge head including a multi-layer piezoelectric element from Example 55
[00205] A liquid discharge apparatus shown in Figure 6 was manufactured using a liquid discharge head shown in Figure 2 including a multilayer piezoelectric element of Example 55. The discharge of ink onto a recording medium in response to incoming electrical signals was confirmed. Ultrasonic motor including a multi-layer piezoelectric element from Example 55
[00206] An ultrasonic motor shown in Figure 3B was manufactured using the multilayer piezoelectric element from Example 55. The rotation of a motor in response to applied AC voltage was confirmed.
[00207] Lens cylinder using an ultrasonic motor that includes a multi-layer piezoelectric element from Example 55
[00208] An optical apparatus shown in Figures 8A and 8B was manufactured using the multilayer piezoelectric element of Example 55. The operation of autofocus in response to the applied AC voltage was confirmed. Electronic apparatus using a piezoelectric acoustic component including a multilayer piezoelectric element from Example 55
[00209] An electronic apparatus shown in Figure 10 was manufactured using a piezoelectric acoustic component including a multilayer piezoelectric element from Example 55. The operation of a speaker in response to applied AC voltage was confirmed. Other Modalities
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the exemplary embodiments set forth. The scope of the following claims shall be accorded the broadest interpretation to cover all such modifications and equivalent structures and functions.
[00211] This application claims the benefit of Japanese Patent Application No. 2011-149361, filed July 5, 2011, which is incorporated herein by reference in its entirety. Industrial Applicability
[00212] A piezoelectric element according to the invention operates stably over a wide operating temperature range, has low impact on the environment, and can be used in apparatus such as liquid discharge heads and ultrasonic motors, which use a large amount of piezoelectric materials in the piezoelectric elements, etc. List of Reference Signals
[00213] 1 first electrode
[00214] 2 piezoelectric material
[00215] 3 second electrode
[00216] 101 the piezoelectric element
[00217] 102 individual liquid reservoir
[00218] 103 vibration plate
[00219] 104 separation
[00220] 105 discharge orifice
[00221] 106 communication hole
[00222] 107 common reservoir
[00223] 108 intermediate layer
[00224] 1011 first electrode
[00225] 1012 piezoelectric material
[00226] 1013 second electrode
[00227] 201 vibrator
[00228] 202 rotor
[00229] 203 output shaft
[00230] 204 vibrator
[00231] 205 rotor
[00232] 206 spring
[00233] 2011 elastic ring
[00234] 2012 the piezoelectric element
[00235] 2013 organic adhesive
[00236] 2041 the elastic metal element
[00237] 2042 the multilayer piezoelectric element
[00238] 51 first electrode
[00239] 53 second electrode
[00240] 54 layer of piezoelectric material
[00241] 55 internal electrode
[00242] 501 first electrode
[00243] 503 second electrode
[00244] 504 layer of piezoelectric material
[00245] 505 internal electrode
[00246] 506a external electrode
[00247] 506b external electrode
[00248] 701 front lens group
[00249] 702 rear lens (focus lens)
[00250] 711 support
[00251] 712 fixed cylinder
[00252] 713 linear guide cylinder
[00253] 714 lens group front cylinder
[00254] 715 cam ring
[00255] 716 lens group rear cylinder
[00256] 717 cam roller
[00257] 718 axle bolt
[00258] 719 roller
[00259] 720 rotation drive ring roller 722
[00260] 724 manual focus ring
[00261] 725 ultrasonic motor
[00262] 726 corrugated washer
[00263] 727 ball track
[00264] 728 focus switch
[00265] 729 the joint element
[00266] 732 washer
[00267] 733 low friction plate
[00268] 881 liquid discharge apparatus
[00269] 882 outer box
[00270] 883 external box
[00271] 884 external box
[00272] 885 outer box
[00273] 887 outer box
[00274] 890 recovery unit
[00275] 891 recording unit
[00276] 892 car
[00277] 896 main body
[00278] 897 automatic feed unit
[00279] 898 discharge slot
[00280] 899 transport unit
[00281] 901 optical device
[00282] 908 release button
[00283] 909 strobe light unit
[00284] 912 speaker
[00285] 914 microphone
[00286] 916 auxiliary light unit
[00287] 931 main body
[00288] 932 zoom lever
[00289] 933 power button

权利要求:
Claims (17)
[0001]
1. Piezoelectric element, characterized by the fact that it comprises: a first electrode (1); a second electrode (3); and a piezoelectric material (2) including crystal grains of a perovskite type metal oxide represented by the general formula (1) as a major component, and
[0002]
2. Piezoelectric element according to claim 1, characterized in that the crystal grains have a mean circular equivalent diameter of 1 μm or greater and 10 μm or less.
[0003]
3. Piezoelectric element according to claim 1 or 2, characterized in that the piezoelectric material (2) has a relative density of 91.8% or higher and 100% or lower.
[0004]
4. Piezoelectric element according to any one of claims 1 to 3, characterized in that the piezoelectric material (2) has a relative density of 91.8% or higher and 98.7% or lower.
[0005]
5. Piezoelectric element according to any one of claims 1 to 4, characterized in that the Curie temperature of the piezoelectric material (2) is 85°C or more.
[0006]
6. Piezoelectric element according to any one of claims 1 to 4, characterized in that x and y in the main component of the piezoelectric material (2) satisfy 0.125 < x < 0.175 and 0.055 < y < 0.09, respectively, and the content of manganese with respect to 100 parts by weight of perovskite-type metal oxide is 0.02 parts by weight or more and 0.10 parts by weight or less on a metal basis.
[0007]
7. Piezoelectric element according to any one of claims 1 to 6, characterized in that 0.996 < A/B < 0.999, where A is the molar amount of Ba and Ca at sites A and B is the molar amount of Ti, Zr and Mn at B sites in perovskite-type metal oxide.
[0008]
8. Piezoelectric element according to any one of claims 1 to 7, characterized in that x and y in the main component of the piezoelectric material (2) satisfy 0.155 < x < 0.300 and 0.041 < y < 0.069, respectively, and the manganese content with respect to 100 parts by weight of metal oxide of the perovskite type it is 0.12 parts by weight or more and 0.40 parts by weight or less on a metal basis.
[0009]
9. Piezoelectric element according to any one of claims 1 to 8, characterized in that 0.993 < A/B < 0.998, where A is the molar amount of Ba and Ca at sites A and B is the molar amount of Ti, Zr and Mn at B sites in perovskite-type metal oxide.
[0010]
10. Method for producing a piezoelectric element, characterized in that it comprises: forming a compact consisting of a raw material powder comprising a Ba compound, a Ca compound, a Ti compound, a Zr compound, and a Mn compound ; obtaining the piezoelectric material (2) defined in claim 1 by sintering the compact; and providing a first electrode (1) and a second electrode (3) for the piezoelectric material (2).
[0011]
11. Method for producing a piezoelectric element according to claim 10, characterized in that a sintering temperature of the compact is 1200°C or more and 1550°C or less.
[0012]
12. Multilayer piezoelectric element, characterized in that it comprises: layers of piezoelectric material (504); and electrodes including an inner electrode (505), wherein the layers of piezoelectric material (504) and the electrodes are stacked alternately; the piezoelectric material layers (504) contain the piezoelectric material as defined in any one of claims 1 to 9.
[0013]
13. Liquid discharge head, characterized in that it comprises: a liquid reservoir (102) including a vibration unit including the piezoelectric element as defined in any one of claims 1 to 9 or the multilayer piezoelectric element as per defined in claim 13; and a discharge port in communication with the liquid reservoir.
[0014]
14. Apparatus for discharging a liquid, characterized in that it comprises: a transport unit (899) configured to transport a recording medium; and the liquid discharge head as defined in claim 13.
[0015]
15. Ultrasonic motor, characterized in that it comprises: a transducer including the piezoelectric element (2012) as defined in any one of claims 1 to 9 or the multilayer piezoelectric element as defined in claim 12; and a movable element in contact with the vibrating element.
[0016]
16. Optical apparatus, characterized in that it comprises: a drive unit including the ultrasonic motor as defined in claim 15.
[0017]
17. Electronic device, characterized in that it comprises: the piezoelectric element as defined in any one of claims 1 to 9 or the multilayer piezoelectric element as defined in claim 12.

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法律状态:
2018-12-11| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|

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2021-02-02| B15K| Others concerning applications: alteration of classification|Free format text: AS CLASSIFICACOES ANTERIORES ERAM: H02N 2/16 , H01L 41/09 , H01L 41/187 , H02N 2/10 , B41J 2/14 , C04B 35/468 , G02B 7/00 Ipc: C04B 35/468 (2006.01), C04B 35/622 (2006.01), C04B |

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2021-02-17| B07A| Technical examination (opinion): publication of technical examination (opinion) [chapter 7.1 patent gazette]|

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2021-06-01| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

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2021-08-03| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 26/06/2012, OBSERVADAS AS CONDICOES LEGAIS. |

优先权:

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申请号 | 申请日 | 专利标题

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JP2011149361|2011-07-05|

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JP2011-149361|2011-07-05|

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PCT/JP2012/066837|WO2013005701A1|2011-07-05|2012-06-26|Piezoelectric element, multilayered piezoelectric element, liquid discharge head, liquid discharge apparatus, ultrasonic motor, optical apparatus, and electronic apparatus|

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