JP2000022232A - Piezoelectric element, ink ject type recording head, and control and manufacture of piezoelectric element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystal structure of a piezoelectric element using lead titanate, a method for manufacturing the crystal structure, and a method for controlling the crystal structure. SOLUTION: The piezoelectric element made of lead titanate exhibits a crystalline structure remarkably different depending on whether its burning temperature is lower or higher than 700 deg.C. A crystal having extremely less remnant polarization on the one hand and a crystal exhibiting hysteresis characteristics with an extremely high saturation polarization on the other hand are obtained, depending on differences in the crystalline structure. Accordingly, differences in the crystalline structure cause different drive signals Sd1 and Sd2 to be applied to the piezoelectric element, thus obtaining different displacements δ1 and δ2 corresponding thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric element used in an ink jet recording head or the like, and more particularly, to a special structure when lead titanate is used as a piezoelectric ceramic, a control method thereof, a manufacturing method, and the like. The present invention relates to an ink jet recording head.

[0002]

2. Description of the Related Art Piezoelectric devices are made of crystallized ferroelectric or paraelectric piezoelectric ceramics. The composition of the piezoelectric ceramic is generally composed of a two-component system containing lead zirconate titanate (hereinafter referred to as “PZT”) as a main component, or a three-component system obtained by adding a third component to this two-component PZT. Ferroelectrics using binary PZT have been reported in Applied Physics Letters, 1991, vol.58, No11, p.
p1161-1163. Further, Japanese Patent Application Laid-Open No. 6-400
No. 35 discloses a piezoelectric body using binary PZT.

[0003]

However, although lead titanate was suggested to be usable as a piezoelectric ceramic, it was recognized that the firing temperature for crystallization and the difference in characteristics caused by the firing temperature were different. Had not been.

[0004] The applicant of the present application has clarified the characteristics, control method and manufacturing conditions of lead titanate as a piezoelectric ceramic. As a result, they found that by adjusting the firing temperature of a piezoelectric element using lead titanate to a constant condition, two types of piezoelectric elements having remarkable differences in voltage / polarization characteristics can be separately produced. .

[0005]

That is, the first aspect of the present invention is as follows.
An object of the present invention is to provide a piezoelectric element and an ink jet recording head which have low residual polarization and can cause large displacement. A second object of the present invention is to provide a piezoelectric element and an ink jet recording head which exhibit hysteresis characteristics and can perform large displacement control with small voltage fluctuation. A third object of the present invention is to clarify a method for controlling a piezoelectric element which solves the first object. A fourth object of the present invention is to clarify a method for controlling a piezoelectric element which solves the second object. A fifth object of the present invention is to provide a method for manufacturing a piezoelectric element which solves the first object. A sixth object of the present invention is to provide a method of manufacturing a piezoelectric element which solves the second object.

The present invention for solving the first problem is a piezoelectric element having a piezoelectric thin film sandwiched between a lower electrode and an upper electrode, wherein the piezoelectric ceramic constituting the piezoelectric thin film is made of lead titanate. And the crystal is <
The ratio of the <001> orientation to the 100> orientation is 0.5
To 2.0 in the range.

The invention for solving the above-mentioned second problem is directed to a piezoelectric element having a piezoelectric thin film sandwiched between a lower electrode and an upper electrode, wherein the piezoelectric ceramic constituting the piezoelectric thin film is made of lead titanate. The crystal has a feature that the abundance ratio of <100> orientation to all orientations is 0.7 or more, and the abundance ratio of <001> orientation to <100> orientation is 0.5 or less. This is a piezoelectric element.

Further, the invention for solving the above first and second problems is characterized in that a pressure chamber substrate in which a pressure chamber is formed, a diaphragm provided on one surface of the pressure chamber, and a pressure chamber of the diaphragm are provided. An ink jet recording head, comprising: a piezoelectric element according to the present invention, which is provided at a corresponding position and is capable of causing a volume change to the pressure chamber.

The invention for solving the third problem is characterized in that the electric field is changed in a region where the applied electric field and the corresponding polarization are substantially proportional to the applied electric field / dielectric polarization characteristics of the piezoelectric element. This is a method for controlling the piezoelectric element.

According to the invention for solving the above-mentioned fourth problem, in the applied electric field / dielectric polarization characteristics of the piezoelectric element, the direction of change of the electric field changes positively or negatively in a region where the applied electric field and the corresponding polarization exhibit hysteresis characteristics. And controlling a volume change of the piezoelectric element by controlling the volume of the piezoelectric element.

[0011] The invention for solving the fifth problem is a method of manufacturing a piezoelectric element, characterized in that a firing temperature is set to a temperature lower than 680 ° C in a heat treatment step for crystallizing a piezoelectric thin film. is there.

[0012] The invention for solving the above-mentioned sixth object is a method of manufacturing a piezoelectric element, characterized in that a baking temperature is set to a temperature higher than 740 ° C in a heat treatment step for crystallizing a piezoelectric thin film. is there.

[0013]

Embodiments of the present invention will now be described with reference to the drawings. In this embodiment, the structure of lead titanate is clarified, and a piezoelectric element and an ink jet recording head are manufactured.

(Structure) First, the structure of the piezoelectric element of the present invention and the ink jet recording head using the same will be described. FIG. 4 is an exploded perspective view of the ink jet recording head of the present embodiment. FIG. 5 is a partial cross-sectional view of a main part of the ink jet recording head. As shown in FIG. 4, the ink jet recording head 1 includes a nozzle plate 10, a pressure chamber substrate 2.
0, a diaphragm 30 and a housing 25. The piezoelectric element of the present invention is provided on the back side of the diaphragm 30 in FIG.

As shown in FIGS. 4 and 5, the pressure chamber substrate 20 has a cavity (pressure chamber) 21, a side wall (partition) 22,
A reservoir 23 and a supply port 24 are provided. The cavity 21 is a space formed by etching a substrate such as silicon to store ink and the like. The side wall 22 is formed so as to partition between the cavities 21. The reservoir 23 is provided with each cavity 21
Is formed as a flow path for commonly filling the ink. The supply port 24 is connected to each cavity 2 from the reservoir 23.
1 is formed so that ink can be introduced.

The vibration plate 30 is bonded to one surface of the pressure chamber substrate 20. The vibration plate 30 is provided with the piezoelectric element 40 of the present invention. The piezoelectric element 40 is formed by crystallizing a piezoelectric ceramic of lead titanate into a crystal having a perovskite structure, and is formed on the diaphragm 30 in a predetermined shape.

The nozzle plate 10 is bonded to the pressure chamber substrate 20 such that the nozzle holes 11 are arranged at positions corresponding to the cavities 21 provided in the pressure chamber substrate 20. Pressure chamber substrate 2 with nozzle plate 10 attached
0 is further inserted into the housing 25 as shown in FIG.
The inkjet recording head 1 is configured.

FIG. 3 is a sectional view for explaining the layer structure of the piezoelectric element 40. As shown in FIG. 3, the vibration plate 30 is formed by stacking an insulating film 31 and a lower electrode 32, and the piezoelectric element 40 is formed by stacking a piezoelectric thin film layer 41 and an upper electrode.

The insulating film 31 is made of a non-conductive material, for example, silicon dioxide formed by thermally oxidizing a silicon substrate. The insulating film 31 is deformed by a change in volume of the piezoelectric layer, and instantaneously changes the pressure inside the cavity 21. It is configured so as to be able to be increased.

The lower electrode 32 is an electrode paired with the upper electrode 42 for applying a voltage to the piezoelectric thin film layer, and has a conductive material, for example, a titanium (Ti) layer, a platinum (P) layer.
t) and a titanium (Ti) layer.
The reason why the plurality of layers are stacked to form the lower electrode is to enhance the adhesion between the platinum layer and the piezoelectric thin film layer and between the platinum layer and the insulating film. The upper electrode film 42 is the other electrode for applying a voltage to the piezoelectric thin film layer, and is made of a conductive material, for example, platinum (Pt) having a thickness of 0.1 μm.

The piezoelectric thin film layer 41 is made of lead titanate (PbT
It is formed of piezoelectric ceramics composed of iO ₃ ). Regarding the crystal structure of lead titanate, two modes appear depending on the firing temperature. One is the case where the firing temperature for crystallizing the piezoelectric thin film layer is set at 680 ° C. or lower, and as shown in the X-ray diffraction characteristics of FIG. 1, the <001> orientation relative to the <100> orientation of the crystal. Is 0.
A crystal characterized by being in the range of 5 to 2.0. The other is the case where the firing temperature for crystallizing the piezoelectric thin film layer is set to 740 ° C. or higher, and as shown in the X-ray diffraction characteristics of FIG.
> The orientation ratio is 0.7 or more, and <100
The crystal is characterized in that the ratio of the <001> orientation to the> orientation is 0.5 or less. The difference between the two characteristics will be described later.

If the thickness of the piezoelectric thin film layer is too large, a high driving voltage is required. On the other hand, if the thickness is too small, the film thickness cannot be made uniform, and the characteristics of each piezoelectric element separated after the etching will vary, or the number of manufacturing steps will increase, making it impossible to manufacture at a reasonable cost. Therefore, the thickness of the piezoelectric thin film layer 41 is preferably about 500 nm to 1500 nm.

The principle of ejecting ink droplets in the structure of the ink jet recording head will be described. Piezoelectric element 40
When no voltage is applied between the lower electrode 32 and the upper electrode 42, the piezoelectric thin film layer 41 does not change in volume. No pressure change occurs in the cavity 21 in which the piezoelectric element 40 to which the voltage is not applied is provided, and no ink droplet is ejected from the nozzle hole 11.

On the other hand, when a constant voltage is applied between the lower electrode 32 and the upper electrode 42 of the piezoelectric element 40, the volume of the piezoelectric thin film layer 41 changes. In the cavity 21 in which the piezoelectric element 40 to which the voltage is applied is provided, the vibration plate 30 is largely bent. Therefore, the cavity 21
The pressure inside increases instantaneously, and ink droplets are ejected from the nozzle holes 11.

(Description of Manufacturing Method) Next, a method of manufacturing an ink jet recording head according to the present invention will be described together with a method of manufacturing a piezoelectric element. 6 and 7 are cross-sectional views showing manufacturing steps for explaining a method of manufacturing the piezoelectric element and the ink jet recording head according to the present embodiment. This manufacturing method uses a so-called sol-gel method. Production of sol:
A sol of piezoelectric ceramics, which is a raw material for a piezoelectric thin film layer, is manufactured. First, a solute as a raw material of a sol and a solvent as shown in Table 1 are prepared.

[0026]

[Table 1]

Specifically, titanium tetraisopropoxide is added to 2-n-butoxyethanol, and the mixture is stirred at room temperature for 30 minutes. Next, iminodiethanol is added thereto, and the mixture is further stirred at room temperature for 30 minutes. Add lead acetate and add 8
Warm to 0 ° C. and stir for 30 minutes. The solution is naturally cooled to room temperature, and finally polyethylene glycol is added and the mixture is stirred at room temperature for 5 minutes. Through the above steps, an alcohol-based sol solution is completed. In addition, 2-n-butoxyethanol is a main solvent. Iminodiethanol promotes dissolution of lead acetate and serves to inhibit hydrolysis of titanium tetraisopropoxide.

Insulating film forming step (FIG. 6A): In parallel with the production of the sol, an insulating film 31 is formed on the silicon substrate 20. As the silicon substrate 20, for example, 200 μm
m is used. The insulating film 31 is formed to a thickness of about 1 μm. For the production of the insulating film, a known thermal oxidation method or the like is used.

Lower electrode forming step (FIG. 6B): Next, a lower electrode 32 is formed on the insulating film 31. Lower electrode 3
2 is, for example, a titanium layer, a titanium oxide layer, a titanium layer, a platinum layer, a titanium layer of 0.01 μm, 0.01 μm, 0.00
The layers are laminated at a thickness of 5 μm, 0.5 μm, and 0.005 μm. These layers are manufactured by a known direct current sputtering method or the like.

Step of forming piezoelectric layer (FIGS. 6C and 6D):
Next, a piezoelectric thin film layer 41 is formed on the upper electrode 32 using the above sol. First, the sol is applied on the lower electrode to a certain thickness. For example, when a known spin coating method is used, coating is performed at 500 rotations per minute for 30 seconds, at 1500 rotations per minute for 30 seconds, and finally at 500 rotations per minute for 10 seconds.
After the application, the coating is dried at a constant temperature (for example, 180 degrees) for a certain time (for example, about 10 minutes). Drying causes the solvent butoxyethanol to evaporate. After drying, degreasing is further performed at a predetermined high temperature (for example, 400 ° C.) for a certain period of time (30 minutes) in an air atmosphere. By degreasing, the organic ligand coordinated to the metal is thermally decomposed, and the metal is oxidized to a metal oxide. This coating → drying → degreasing process is performed a predetermined number of times,
For example, eight thin film layers are laminated by repeating eight times (FIG. 6).
(C) → FIG. 6 (d) → FIG. 6 (c) → ...). By these drying and degreasing, a metal-oxygen-metal network is formed between the metal alkoxide and the acetate in the solution through thermal decomposition of the ligand.

After forming the four thin film layers and after forming the eight thin film layers, a baking treatment is further performed under a constant atmosphere. Depending on how the temperature at this time is set, the form of the crystallized lead titanate is divided into two types as described above. For the firing treatment, an electric furnace or the like that is usually used is used.

For example, a rapid heat treatment (R
When TA (Rapid Thermal Annealing) is applied, for example, when baked at 680 ° C. or lower for 5 minutes, the crystallized lead titanate has an abundance ratio of <001> orientation to <100> orientation of 0.5 to 2.0. (Fig. 1
reference).

On the other hand, when high-speed heat treatment is performed at a relatively high temperature, for example, when calcination is performed at 740 ° C. or more for 5 minutes, the crystallized lead titanate has an existing ratio of <100> orientation to all orientations of 0.7 or more. And a crystal in which the ratio of the <001> orientation to the <100> orientation is 0.5 or less (see FIG. 2).

As can be seen from the above, the crystal structure changes significantly depending on whether the firing is performed at a lower temperature or a higher temperature at around 700 ° C. This is considered to be due to a difference in crystal growth during crystallization. It is considered that the crystal of lead titanate grows with titanium oxide (TiO2) as a crystal nucleus and grows with lead oxide (PbO) as a crystal nucleus. Based on the inter-ion electrostatic force and the interatomic distance, the [100] orientation is dominant when titanium oxide is used as a nucleus, and the [001] orientation is used when lead oxide is used as a nucleus. However, at a high temperature of 700 ° C. or more, lead oxide tends to evaporate or diffuse. Therefore, when sintered and crystallized at a temperature exceeding 700 ° C., the effect of lead oxide is reduced,
The occupancy of the [100] orientation increases.

The two types of piezoelectric elements manufactured by different firing temperatures have different crystal structures due to their different crystal structures.
Dielectric polarization characteristics with respect to an applied electric field are different from each other. That is, firing at a relatively low temperature <100> orientation <
001> In the case of a crystal in which the orientation ratio is in the range of 0.5 to 2.0, for example, the applied electric field-
Shows polarization characteristics. As can be seen from FIG.
In the range A of 0 [kV / cm] or less, the applied electric field is substantially proportional to the polarization. In this region, since the remanent polarization Pr is very small, it is possible to form a piezoelectric element in which the amount of change in polarization with respect to the increase in the electric field, that is, the change in volume is large and a large displacement can be obtained with a small electric field. When the applied electric field is 200 [k
V / cm], the applied electric field-polarization characteristic has hysteresis as the range B and the range C are advanced. In the range D, a considerably remarkable hysteresis loop is shown. In this range, the polarization direction cannot be changed without reversing the application direction of the electric field.

On the other hand, it is baked at a relatively high temperature and the ratio of <100> orientation to all orientations is 0.7 or more, and the ratio of <001> orientation to <100> orientation is 0.5 or less. In the case of the resulting crystal, for example, an applied electric field-polarization characteristic as shown in FIG. 9 is exhibited. As can be seen from FIG. 9, while the applied electric field is low, the same applied electric field-polarization characteristics as those in the range D of FIG. 8 are exhibited. In a piezoelectric element having this hysteresis characteristic, the direction of polarization, that is, the direction of volume change, can be reversed depending on whether the applied electric field (voltage) changes in an increasing direction or a decreasing direction. That is, by applying a control electric field (voltage) that monotonically increases or monotonically decreases with the passage of time, it becomes possible to control the piezoelectric element having this crystal structure.

By the above calcination treatment, a perovskite crystal structure having any crystal structure is formed from the gel in an amorphous state.

Upper Electrode Forming Step (FIG. 6E): An upper electrode 42 is formed on the piezoelectric thin film layer 41 by using a technique such as an electron beam evaporation method or a sputtering method. As a material of the upper electrode, platinum (Pt) or the like is used. The thickness is 100n
m.

The original shape of the piezoelectric element is completed through the above steps. By etching this piezoelectric element into a shape suitable for the application location, it is possible to operate as the piezoelectric element of the present invention. In the present embodiment, an ink jet recording head is manufactured by etching the laminated structure of the piezoelectric element so as to be compatible with the ink jet recording head.

Etching Step (FIG. 7A): After forming each layer, the upper electrode 42 and the piezoelectric thin film layer 41 are masked so as to have a shape conforming to each cavity 21, and the periphery thereof is etched. Specifically, first, the spinner method,
A resist material having a uniform thickness is applied using a method such as a spray method. Next, a mask is formed in the shape of the piezoelectric element, exposed and developed to form a resist pattern on the upper electrode 4.
2 is formed. The upper electrode and the piezoelectric thin film layer are etched and removed by applying ion milling, a dry etching method or the like which is usually used for this.

Pressure Chamber Forming Step (FIG. 7B): The other surface of the pressure chamber substrate 20 on which the piezoelectric element 40 is formed is etched to form a cavity 21. For example, the cavity 21 space is etched using anisotropic etching using an active gas such as anisotropic etching and parallel plate type reactive ion etching. The portion left without being etched becomes the side wall 22.

Nozzle plate bonding step (FIG. 7 (c)):
The nozzle plate 10 is attached to the pressure chamber substrate 20 after the etching with an adhesive. At the time of bonding, each nozzle hole 11
Are positioned in the space of each cavity 21. Pressure chamber substrate 20 to which nozzle plate 10 is attached
Is attached to the housing 25 (see FIG. 4), and the ink jet recording head 1 is completed. Instead of bonding the nozzle plate 10, the nozzle plate and the pressure chamber substrate may be integrally etched and formed. When the nozzle plate and the pressure chamber substrate are manufactured at the same time by integrally etching, the bonding step is unnecessary. The nozzle hole is opened at a position corresponding to the cavity.

Example A piezoelectric element having two types of crystal structures was manufactured according to the above embodiment. As Example 1, a piezoelectric element made of lead titanate crystallized at a relatively low firing temperature of 600 ° C. will be described. The thickness is 1.0 μm.
As a second embodiment, a piezoelectric element made of lead titanate crystallized at a relatively high firing temperature of 850 ° C. will be described. The film thickness is
1.0 μm. As a comparative example, a conventional piezoelectric element (PZT) will be described. The firing treatment was performed at 650 ° C. for 5 minutes, and further at 850 ° C. for 1 minute. The thickness is 1.0 μm.

FIG. 1 shows the X-ray diffraction characteristics (2θ) of the piezoelectric element of the first embodiment. As is clear from FIG. 1, the crystal orientations are <001> orientation, <100> orientation, <
The 110> and <101> orientations were mainly observed. Among them, it can be seen that the abundance ratio of the <001> orientation to the <100> orientation is 0.7, which is in the range of 0.5 to 2.0.

FIG. 2 shows the X-ray diffraction characteristic (2θ) of the piezoelectric element of the second embodiment. As is clear from FIG. 2, <001>, <100>, <110>, and <101> orientations were mainly observed as crystal orientations. Among them, it can be seen that the abundance ratio of <100> orientation to all orientations is remarkably large, and is 0.7 or more. Also, it can be seen that the abundance ratio of the <001> orientation to the <100> orientation is about 0.2, and is within 0.5 or less.

FIG. 8 shows the polarization characteristics of the piezoelectric element of Example 1 with respect to an applied electric field. The hysteresis loop of FIG. 8 was measured using a 1 μF load capacitor Sawyer tower circuit with a 60 Hz sine wave applied. FIG.
It is presumed that the reason why the hysteresis loop is asymmetric in the above is due to the difference in the interface state between the piezoelectric thin film layer and the upper electrode. As can be seen from FIG. 8, in the first embodiment, 200 kV
/ Cm] or less at low electric fields of less than or equal to
Then comes the hysteresis.

FIG. 9 shows the polarization characteristics of the piezoelectric element of Example 2 with respect to an applied electric field. As can be seen from FIG. 9, in Example 2, the electric field-polarization characteristic shows a remarkable hysteresis from a low electric field of 200 [kV / cm] or less. In this state, it is possible to reverse the polarization direction by changing the change direction of the electric field (voltage).

The waveform of the control signal for driving the piezoelectric element is determined from the difference in the above characteristics. FIG. 10A shows the waveform of the drive signal Sd1 for driving the piezoelectric element as in Example 1 fired at a relatively low temperature. A voltage proportional to the magnitude of the volume change is applied between the upper electrode and the lower electrode of the piezoelectric element in accordance with the timing at which the volume change is desired. By adding the drive signal Sd1, the piezoelectric element undergoes a volume change with a characteristic like a dashed line δ1 in FIG. The reason why the offset is provided in the drive signal is that
This is for generating a meniscus of the ink at the nozzles and improving the ink ejection performance. When this piezoelectric element is used for an actuator of an ink jet recording head, it is possible to eject an amount of ink according to the voltage value. At this time, since the residual strain is smaller than that of the piezoelectric element of the comparative example, an efficient electromechanical conversion action can be expected. Also, since the dielectric constant is relatively low, an element having a small capacity can be provided, and the load on the load circuit can be reduced.

FIG. 10B shows the waveform of the drive signal Sd2 for driving the piezoelectric element as in the second embodiment fired at a relatively high temperature. In this manner, a sawtooth voltage is applied between the upper electrode and the lower electrode of the piezoelectric element so that the direction of change of the drive signal is reversed at the timing when a volume change is desired. By adding the drive signal Sd2, the piezoelectric element undergoes a volume change with a characteristic like a dashed line δ2 in FIG. When this piezoelectric element is used for an actuator of an ink jet recording head, it is possible to discharge a fixed amount of ink with a slight voltage change. At this time, since the dielectric constant is relatively low as compared with the piezoelectric element of the comparative example, the element can be a small-capacity element and the load on the load circuit can be reduced. Further, since the ink ejection can be controlled in the voltage change direction, the load on the load circuit can be further reduced.

Further, since such a remarkable hysteresis characteristic can be used as a storage unit, it is possible to configure a memory by arranging a plurality of piezoelectric elements in parallel and applying a voltage individually. That is, in the piezoelectric element of the second embodiment, the saturation polarization or the residual polarization is as large as 40 [μC / cm ² ] even if the absolute value of the control voltage is lower than 8V. Therefore, it is possible to use the memory as a rewritable memory by supplying a drive signal in accordance with the information logic to be recorded, writing the data, detecting the polarization direction and reading the information.

(Other Modifications) The present invention can be variously modified and applied irrespective of the above embodiments. For example, in the above embodiment, the piezoelectric thin film layer is crystallized using the sol-gel method. However, the piezoelectric thin film layer may be crystallized from an organic metal precursor by a MOD method, a coprecipitation method, or a hydrothermal method. Good. At this time, even if the heat treatment temperature for obtaining the two types of crystal structures is different, the same effects as those of the above embodiment can be obtained if the above-mentioned orientation characteristics are observed in the crystal structures.

The piezoelectric element manufactured by the present invention is not limited to the piezoelectric element of the above-mentioned ink jet recording head, but also includes a nonvolatile semiconductor memory device, a thin film capacitor, a pyroelectric detector, a sensor, and a surface acoustic wave optical waveguide. Applicable to the manufacture of ferroelectric devices, dielectric devices, pyroelectric devices, piezoelectric devices, and electro-optical devices such as tubes, optical storage devices, spatial light modulators, frequency doublers for diode lasers, etc. . That is, since the piezoelectric element of the present invention exhibits low dielectric properties, low residual strain, or high saturation polarization, it is possible to provide a piezoelectric element suitable for any use.

[0053]

According to the present invention, since the lead titanate is calcined at a relatively low temperature, it is possible to provide a piezoelectric element and an ink jet recording head having low remanent polarization and large displacement.

According to the present invention, since the lead titanate is calcined at a relatively high temperature, it is possible to provide a piezoelectric element and an ink jet recording head which exhibit hysteresis characteristics and can perform large displacement control with small voltage fluctuation.

[Brief description of the drawings]

FIG. 1 is an X-ray diffraction characteristic diagram (2θ) of a piezoelectric element of the present invention fired at a relatively low temperature (Example 1).

FIG. 2 is an X-ray diffraction characteristic diagram (2θ) of the piezoelectric element of the present invention (Example 2) fired at a relatively high temperature.

FIG. 3 is a cross-sectional view illustrating a laminated structure of the piezoelectric element of the present invention.

FIG. 4 is an exploded perspective view of the ink jet recording head of the present invention.

FIG. 5 is a perspective view, partly in section, of an ink jet recording head of the present invention.

FIG. 6 is a cross-sectional view showing a manufacturing process for explaining the method of manufacturing the ink jet printer head of the present invention (part 1).

FIG. 7 is a cross-sectional view showing a manufacturing step for explaining the method for manufacturing an ink jet printer head of the present invention (part 2).

FIG. 8 is a diagram showing the strength of the dielectric polarization P of the piezoelectric thin film layer with respect to the strength E of the electric field applied to the piezoelectric thin film layer when lead titanate is fired at a relatively low temperature.

FIG. 9 is a diagram illustrating the strength of the dielectric polarization P of the piezoelectric thin film layer with respect to the strength E of the electric field applied to the piezoelectric thin film layer when lead titanate is fired at a relatively high temperature.

10A and 10B are driving characteristic diagrams of a piezoelectric element, in which FIG. 10A is a diagram showing a driving signal and displacement in the piezoelectric element of Example 1 fired at a relatively low temperature, and FIG. It is a figure which shows the drive signal and displacement in the piezoelectric element of Example 2 baked at the temperature.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Nozzle plate 20 ... Pressure chamber substrate 30 ... Vibration plate 31 ... Insulating film 32 ... Lower electrode 40 ... Piezoelectric element 41 ... Piezoelectric thin film layer 42 ... Upper electrode 11 ... Nozzle 21 ... Cavity

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B41J 2/055

Claims (7)

[Claims] 1. A piezoelectric element comprising a piezoelectric thin film sandwiched between a lower electrode and an upper electrode, wherein the piezoelectric ceramic constituting the piezoelectric thin film is made of lead titanate, and the crystal of which is <100. A piezoelectric element, wherein the ratio of the <001> orientation to the> orientation is in the range of 0.5 to 2.0. 2. A piezoelectric element comprising a piezoelectric thin film sandwiched between a lower electrode and an upper electrode, wherein the piezoelectric ceramics constituting the piezoelectric thin film is made of lead titanate, and the crystal of which is oriented in all directions. <100> orientation is 0.7 or more with respect to
The existence ratio of the <001> orientation to the <100> orientation is 0.1.
A piezoelectric element having a size of 5 or less. 3. An ink jet recording head provided with the piezoelectric element according to claim 1, wherein a pressure chamber substrate in which a pressure chamber is formed, and a vibration provided on one surface of the pressure chamber. An ink jet type recording comprising: a plate; and the piezoelectric element provided at a position corresponding to the pressure chamber of the vibration plate, and configured to be able to apply a volume change to the pressure chamber. head. 4. The method for controlling a piezoelectric element according to claim 1, wherein in the applied electric field / dielectric polarization characteristics of the piezoelectric element, an electric field is applied in a region where the applied electric field and the corresponding polarization are substantially proportional. A method for controlling a piezoelectric element, wherein the method is changed. 5. The method of controlling a piezoelectric element according to claim 2, wherein in the applied electric field / dielectric polarization characteristic of the piezoelectric element, an electric field is applied in a region where the applied electric field and the corresponding polarization exhibit hysteresis characteristics. A volume change of the piezoelectric element by changing a change direction of the piezoelectric element to positive or negative. 6. The piezoelectric element manufacturing method according to claim 1, wherein in the heat treatment step for crystallizing the piezoelectric thin film, a firing temperature is set to a temperature lower than 680 ° C. Method for manufacturing a body element. 7. The method for manufacturing a piezoelectric element according to claim 2, wherein in the heat treatment step for crystallizing the piezoelectric thin film, a firing temperature is set to a temperature higher than 740 ° C. Method for manufacturing a body element.