JP3319223B2 - Piezoelectric element and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric element formed directly on the surface of a thin tubular metal cylinder having a piezoelectric layer as a base, and a method of manufacturing the same. The present invention relates to a piezoelectric element used as a piezoelectric element and a method for manufacturing the same.

[0002]

2. Description of the Related Art Piezoelectric bodies made of piezoelectric ceramics typified by lead zirconate titanate (hereinafter abbreviated as PZT) reciprocate electric energy and mechanical energy utilizing their high piezoelectric effect and reverse piezoelectric effect. Widely used as a conversion element. In the method of manufacturing PZT piezoelectric body, PbO as a raw material, preparation of ZrO _2, TiO ₂ powder were mixed, and PZT powder through calcination step, a pulverization step, 1m
m or more after molding by pressure molding method
In general, a solid-phase reaction is performed in a firing step, a polarization process is performed by applying an electric field of about several kv / mm, and electrodes are formed on both surfaces to form a product. Further, a thin plate or a cylindrical piezoelectric body having a thickness of 1 mm or less is manufactured by a method of cutting a piezoelectric body obtained by the above-described pressure molding method into a desired shape and size. Further, a sheet forming method using a doctor blade is generally used for forming a PZT sheet having a thickness of 100 μm or less, and a film forming method such as a sbutter method, a CVD method, or a sol-gel method is also known. Furthermore,
An example of successful production of a PZT thin film having a thickness of about 20 μm by a hydrothermal method of directly forming a PZT thin film on the surface of a titanium substrate through a nucleation step and a crystal growth step in the presence of high-temperature and high-pressure water is described in K. Simamura, Reported by T. Tsurumi, Y. ohba, D. Daimon et al. (Jpn. J. Appl. Phys. 30 (1991) 217)
Four) .

On the other hand, in recent years, an ink jet recording apparatus has attracted attention as a new application field of a piezoelectric element. 2. Description of the Related Art A printing apparatus using an ink jet recording head mechanism is widely used in fields such as a desktop printer and a facsimile, which are required to be small and lightweight because of the advantage of a simple configuration. Several systems have been proposed for the mechanism of the ink jet recording head.
Provide an elongated cylindrical piezoelectric element of about 0 to 200 μm,
A method in which this portion functions as a pressure pump to discharge ink droplets from the nozzle portion is being widely used, taking advantage of features such as semi-permanent head life and low running cost.

[0004]

SUMMARY OF THE INVENTION A diameter of 10 to 2 applicable to the ink jet recording head constructed as described above.
Conventionally, an elongated cylindrical piezoelectric element of about 00 μm is formed by an ink supply pipe section having a nozzle section and a micro valve formed separately at both ends of an elongated cylindrical piezoelectric body formed by a solid-phase reaction method using a molding die. Have been manufactured by a method of forming an ink flow path by hermetically connecting them. For this reason, it is difficult to control the dimensions, composition, and density of the piezoelectric material obtained by the obtained solid-phase reaction method, and it is difficult to obtain sufficient piezoelectric characteristics. There is a problem in that it takes time and labor to perform post-processing, which leads to an increase in manufacturing cost.

Further, the thickness of the piezoelectric material obtained by the CVD method or the sol-gel method is as small as about several μm, and there is a problem that it is difficult to obtain a driving force required for an ink jet recording head. Furthermore, according to the hydrothermal method, a piezoelectric layer can be directly formed on the surface of the substrate, and its composition controllability is excellent,
Although it has the advantage that a homogeneous PZT piezoelectric layer having a thickness of about 20 μm can be formed at the following low temperature, the PZT
There is only a successful example of forming a T layer, and in order to enable application to a cylindrical ink jet recording head, a diameter of 10 to 2 is required.
There is a demand for the establishment of a technique for manufacturing an elongated cylindrical piezoelectric element of about 00 μm.

An object of the present invention is to provide a piezoelectric element in which a piezoelectric layer whose dimensions, composition, and density are accurately controlled is directly formed on an arbitrary surface of a thin cylindrical base, and a method of manufacturing the same.

[0007]

[0008]

In order to achieve the above-mentioned object, according to the first aspect of the present invention, there is provided a hollow metal cylinder made of titanium, and an inner peripheral surface, an outer peripheral surface, Alternatively, a piezoelectric element is constituted by a piezoelectric layer of lead zirconate titanate directly formed on one of the inner and outer surfaces and an electrode formed on the surface of the piezoelectric layer. In manufacturing such a piezoelectric element, a piezoelectric layer is formed through a nucleation step and a crystal growth step by a hydrothermal synthesis method in which the main component of a hollow metal cylinder is used as one synthesis element in the presence of high-temperature and high-pressure water. Is preferably formed directly on the surface of the metal cylinder (the invention according to claim 2).

According to the second aspect of the present invention, the hydrothermal synthesis method comprises adding a 8N aqueous solution of potassium hydroxide to a mixed solution of a lead nitrate aqueous solution and a zirconium oxychloride aqueous solution having a predetermined lead: zirconium molar ratio. A nucleation step of immersing a hollow metal cylinder made of titanium in the treatment liquid with the added mixed solution as a treatment liquid and nucleating lead zirconate titanate for a certain time in a sealed atmosphere at about 150 ° C .; A treatment liquid is obtained by adding a 4N aqueous solution of potassium hydroxide to a mixture of an aqueous solution of lead nitrate, an aqueous solution of zirconium oxychloride, and an aqueous solution of titanium tetrachloride having a predetermined molar ratio of lead: zirconium: titanium. It is preferable to include a crystal growth step of immersing the nucleated metal cylinder and growing lead zirconate titanate in a sealed atmosphere at about 120 ° C. for a certain period of time. (The invention according to claim 3).

Further, in the invention according to claim 2 or 3, a thin film for preventing the formation of a piezoelectric layer is formed in advance on the outer peripheral surface of the hollow metal cylinder, and the thin film of the hollow metal cylinder is formed by hydrothermal synthesis. It is preferable to form the piezoelectric layer directly on the inner peripheral surface (the invention according to claim 4). Furthermore, both ends of the hollow metal cylinder may be plugged, and a piezoelectric layer may be formed directly on the outer peripheral surface of the metal cylinder by hydrothermal synthesis in this state (the invention according to claim 5).

Further, in the invention according to claim 2 or 3, the base is formed by stacking a platinum film and a titanium film on the outer peripheral surface of a rod-shaped plastic material, and the surface of the titanium film on the base is hydrothermally synthesized. It is convenient to directly form a piezoelectric layer made of lead zirconate titanate by a method, and then heat the whole in a lead vapor atmosphere to bake off the rod-shaped plastic material. Described invention).

[0012]

[0013]

According to the first aspect of the present invention, titanium zirconate titanate (PZT) directly formed on the inner peripheral surface, the outer peripheral surface, or the inner and outer surfaces of the hollow metal cylinder using titanium. By providing a piezoelectric layer consisting of
A piezoelectric element having a strong pump action can be obtained by utilizing the excellent piezoelectric characteristics of PZT. On the other hand, in the invention according to claim 2, the metal cylinder is formed through a nucleation step and a crystal growth step by a hydrothermal synthesis method in which the main component of the hollow metal cylinder is used as one synthesis element in the presence of high-temperature and high-pressure water. Since the piezoelectric layer is directly formed on the surface of the piezoelectric element, the exposed surface of the hollow metal cylinder is used as a region for forming the piezoelectric layer. It is possible to manufacture without requiring.

Here, as in the invention according to claim 3,
Since the hydrothermal synthesis method of the PZT layer is a method in which the nucleation step and the crystal growth step are performed using a liquid processing solution, the composition of the PZT layer obtained by adjusting the solution can be controlled accurately, and the high-temperature and high-pressure atmosphere can be controlled. The size and density of the PZT layer obtained by controlling the temperature can be controlled accurately, and the hydrothermal synthesis reaction is performed in the liquid, so that the exposed surface of the metal cylinder is specified without being affected by the size of the metal cylinder. P region with high dimensional accuracy, high relative dielectric constant, piezoelectric constant, and Young's modulus
A piezoelectric element having a ZT layer is obtained.

Further, if a thin film for preventing the formation of the piezoelectric layer is formed on the outer peripheral surface of the hollow metal cylinder in advance, the exposed inner peripheral surface of the metal cylinder can be formed. A piezoelectric element having a piezoelectric layer inside a hollow metal cylinder as a designated area can be easily obtained by a hydrothermal synthesis method. Further, as in the invention according to claim 5, both ends of the hollow metal cylinder are plugged, and in this state, if the piezoelectric layer is directly formed on the outer peripheral surface of the metal cylinder by hydrothermal synthesis, it is exposed. A piezoelectric element having a piezoelectric layer outside a hollow metal cylinder with the outer peripheral surface of the metal cylinder as a designated area can be easily obtained by a hydrothermal synthesis method.

Further, according to the invention described in claim 6,
A piezoelectric layer made of lead zirconate titanate is formed directly on the titanium film surface of this substrate by a hydrothermal synthesis method, with a platinum film and a titanium film superposed on the outer surface of a rod-shaped plastic material. Thereafter, the entire body was heated in a lead vapor atmosphere and the rod-shaped plastic material was calcined and removed, whereby a cylindrical PZT piezoelectric element having a platinum electrode on the inner peripheral surface was obtained.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.
FIG. 1 is a perspective view of a piezoelectric element showing one embodiment of the present invention. In the figure, the piezoelectric element has a thickness of about 10 mm directly on the inner and outer surfaces of a hollow metal cylinder 1 made of titanium having an inner diameter of about 1.2 mm.
Piezoelectric layers 2 and 3 made of a PZT layer having a thickness of μm are formed, and metal electrodes (not shown) are formed on the surfaces of the piezoelectric layers 2 and 3 by a method similar to a conventional method such as a vapor deposition method, a sputtering method, and a coating film baking method. Formed by

Next, a method of manufacturing the piezoelectric element shown in FIG. 1 by the hydrothermal synthesis method will be described. In the nucleation step, an aqueous solution of lead nitrate and an aqueous solution of zirconium oxychloride are mixed so that the molar ratio of lead: zirconium becomes 1.25: 0.52, and a mixed solution obtained by adding an 8 N aqueous solution of potassium hydroxide to this mixed solution. , A hollow metal cylinder 1 made of titanium is immersed in the processing solution, and is heated at 150 ° C. in an autoclave.
Was heated for 48 hours in the closed atmosphere of Example 1 to form nuclei of lead zirconate titanate on the inner and outer peripheral surfaces of the titanium cylinder.

In the crystal growth step, an aqueous solution of lead nitrate, an aqueous solution of zirconium oxychloride and an aqueous solution of titanium tetrachloride are mixed so that the molar ratio of lead: zirconium: titanium is 1.25: 0.52: 0.48. Potassium hydroxide 4 in the liquid
The mixed solution to which the specified aqueous solution was added was used as a treatment liquid, and the metal cylinder 1 having the nucleus formed therein was immersed in the treatment liquid, and crystal growth of lead zirconate titanate was performed in a closed atmosphere at 120 ° C. for 48 hours.

The hydrothermal synthesis consisting of the above two steps is completed,
The washed and dried piezoelectric element is placed on the inner and outer surfaces of the titanium cylinder.
PZT piezoelectric layers 2 and 3 are formed directly on the peripheral surface.
The thickness was about 10 μm each. Also, P
A gold electrode is formed on the surface of the ZT piezoelectric layers 2 and 3 and
As a result of measuring the physical properties, the relative dielectric constant was 1800, and the piezoelectric constant d was
₃₃Is 4.2 × 10^-Tenm / v, Young's modulus is 5.6 × 10
^TenN / m^TwoAnd proved to have good piezoelectric properties
Was done.

FIG. 2 is a perspective view of a piezoelectric element showing another embodiment of the present invention. The embodiment shown in the drawing is different from the embodiment shown in FIG. 1 in that a PZT piezoelectric layer is formed by a hydrothermal synthesis method under the same conditions as in the embodiment shown in FIG. It is in the point which formed. In this case, in the nucleation step, the contact between the treatment liquid and the titanium cylinder is blocked by the platinum electrode 4, so that the nucleation reaction of lead zirconate titanate on the outer peripheral surface of the titanium cylinder is prevented, and A piezoelectric element having the PZT piezoelectric layer 2 only on the peripheral surface is obtained. Obtained PZT piezoelectric layer 2
Had a thickness of about 10 μm. Further, the PZT piezoelectric layer 2
Results of measurement of physical properties by forming gold electrodes on the surface of a dielectric constant of 1650, the piezoelectric constant d ₃₃ is 4 × 10 ^-10 m /
v, Young's modulus was 5.5 × 10 ¹⁰ N / m ^2, and it was proved that the piezoelectric material had good piezoelectric properties as in the example shown in FIG.

FIG. 3 is a perspective view of a piezoelectric element showing still another embodiment of the present invention. The difference between the embodiment shown in the figure and the embodiment shown in FIG. 1 is that both ends of the titanium cylinder 1 are sealed with a plastic sealing material 5 and, in this state, FIG.
Is that a PZT piezoelectric layer was formed by a hydrothermal synthesis method under the same conditions as in the embodiment shown in FIG. In this case, since a hydrothermal synthesis reaction does not occur in the hollow portion of the titanium cylinder 1, a piezoelectric element having the PZT piezoelectric layer 3 only on the outer peripheral surface side of the titanium cylinder 1 is obtained. The thickness of the obtained PZT piezoelectric layer 2 is about 1
It was 0 μm. As a result of forming a gold electrode on the surface of the PZT piezoelectric layer 3 and measuring its physical properties, the relative dielectric constant was 17
00, the piezoelectric constant d ₃₃ was 4 × 10 ⁻¹⁰ m / v, and the Young's modulus was 5.5 × 10 ¹⁰ N / m ² , demonstrating that it has good piezoelectric characteristics as in the example shown in FIG. Was done.

FIG. 4 shows another embodiment of the present invention.
It is a perspective view of a child. The embodiment shown in the figure is the embodiment shown in FIG.
What is different is not shown in place of the titanium cylinder 1
Platinum thin film + titanium thin film on the outer surface of plastic round bar 6
Using the double layer 11 formed, the embodiment shown in FIG.
Forming a PZT piezoelectric layer by hydrothermal synthesis under the same conditions
It is in the point. In this case, a titanium thin film of the double layer 11 is synthesized.
Through the nucleation process, which is one of the components, the PZT piezoelectric layer 3 becomes
It is formed. Therefore, the entire atmosphere of lead vapor at 1000 ° C
Heat for 1 hour in air to incinerate and remove plastic round bar 6
Then, a platinum thin film + titanium thin film is formed on the inner peripheral surface of the PZT layer 3.
A piezoelectric element having the multilayer 11 is obtained. Like this
The thickness of the obtained PZT piezoelectric layer 2 is about 10 μm.
Was. Also, by forming a gold electrode on the surface of the PZT piezoelectric layer 3,
As a result of measuring the physical properties, the relative dielectric constant was 1600 and the piezoelectric constant was
Number d₃₃Is 3.9 × 10^-Tenm / v, Young's modulus is 5.3 ×
10 ^TenN / m^TwoAnd good as in the embodiment shown in FIG.
It was proved that it had excellent piezoelectric characteristics.

FIG. 5 is a perspective view of a piezoelectric element showing another embodiment of the present invention. The embodiment shown in the drawing is different from the embodiment shown in FIG. 3 in that a hollow metal cylinder 21 made of titanium having an inner diameter of 100 μm has a cylindrical portion having an inner diameter of 100 μm as an ink pressurizing chamber section 22 and a nozzle section at one end. 23,
An ink flow path 21 having an ink supply pipe portion 24 at the other end is formed, and the nozzle portion 23 and the hollow portion of the ink supply pipe portion 24 are sealed with a plastic sealing material 6 as in the embodiment shown in FIG. In a state in which a paint for preventing the formation of the piezoelectric layer is applied to the outer peripheral surface, a PZT piezoelectric member is applied to the outer peripheral portion of the ink pressurizing chamber 22 by the hydrothermal synthesis method under the same conditions as in the embodiment shown in FIG. A body layer 3 was formed.

The thickness of the PZT layer 2 thus obtained
Was about 10 μm. The surface of the PZT piezoelectric layer 3
After measuring the physical properties of a gold electrode formed on
Is 1700 and the piezoelectric constant d₃₃Is 4 × 10^-Tenm / v, Yang
5.5 × 10^TenN / m ^TwoAnd the implementation shown in FIG.
It was demonstrated to have good piezoelectric properties as in the examples.
Also, the ink supply tube portion 24 of the obtained piezoelectric element is shown in FIG.
Not integrated into the ink supply via micro valve
Only, the ink ejection characteristics were measured. As a result, PZT piezoelectric
Number of inks corresponding to ON / OFF of the voltage applied to the body layer 3
Drops can be ejected, making it a good inkjet recording head
It has been demonstrated that ink ejection characteristics can be obtained. Note that P
The ZT piezoelectric layer may be formed on the inner peripheral side of the pressure chamber 22.
And transmitting the expansion and contraction of the PZT piezoelectric layer directly to the ink
Good ink ejection characteristics can be obtained. In addition, the pressure of the present invention
Manufacturing method of electric element is limited to PZT piezoelectric element
Rather than manufacturing technology for cylindrical piezoelectric ceramics
Widely applicable.

[0027]

As described above, the piezoelectric element and the method of manufacturing the same according to the present invention employ a hydrothermal synthesis method to adjust the composition, dimensions, and density of the piezoelectric layer by controlling the solution and controlling the temperature. Can be formed directly on the surface of the substrate, and the relative permittivity,
A cylindrical piezoelectric element having a high piezoelectric constant and a good piezoelectric characteristic with a high Young's modulus can be provided economically and advantageously.

Further, by establishing a masking technique, it is possible to directly form the piezoelectric layer on the inner circumference, outer circumference, or any specified area of the inner and outer circumferences of the metal cylinder serving as the base, and to provide the metal cylinder serving as the base. Pre-processing into a structure suitable for the ink flow path eliminates post-processing such as connecting the nozzle and ink supply pipe to the cylindrical piezoelectric element conventionally manufactured by the solid-phase reaction method. Therefore, an ink jet recording head having a piezoelectric pump capable of directly converting vibration of the piezoelectric element into an ink ejection force as a driving pump with low manufacturing cost and economically can be advantageously provided.

Further, since an elongated piezoelectric element having an inner diameter of a metal cylinder of 100 μm or less can be manufactured, it is easy to form a multi-nozzle type ink jet recording head compactly. It is expected to contribute to improving the functions of printers and even inkjet printers that can display gradations.

Further, by using a plastic round bar treated with a metal thin film, a cylindrical piezoelectric element in which a metal cylinder is replaced with a metal thin film as an electrode can be easily obtained. It is expected to be widely used as a piezoelectric element.

[Brief description of the drawings]

FIG. 1 is a perspective view of a piezoelectric element showing an embodiment of the present invention.

FIG. 2 is a perspective view of a piezoelectric element showing a different embodiment of the present invention.

FIG. 3 is a perspective view of a piezoelectric element showing still another embodiment of the present invention.

FIG. 4 is a perspective view of a piezoelectric element showing another embodiment of the present invention.

FIG. 5 is a perspective view of a piezoelectric element showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hollow metal cylinder (titanium cylinder) 2 Piezoelectric layer (PZT, inner peripheral side) 3 Piezoelectric layer (PZT, outer peripheral side) 4 Platinum electrode 5 Plastic sealing material 6 Plastic round bar 10 Titanium cylinder with platinum electrode 11 Platinum film Double layer of titanium and titanium film 21 Hollow metal cylinder (made of titanium, ink flow path) 22 Pressurizing chamber part 23 Nozzle part 24 Ink supply pipe part

Continuation of the front page (56) References JP-A-64-87355 (JP, A) JP-A-8-258273 (JP, A) JP-A-62-233250 (JP, A) JP-A-55-101470 (JP, A) , A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 2/045 B41J 2/055 B41J 2/16 H01L 41/113

Claims (6)

(57) [Claims] 1. A hollow metal cylinder made of titanium, and a piezoelectric layer made of lead zirconate titanate directly formed on one of an inner peripheral surface, an outer peripheral surface, and both inner and outer surfaces thereof based on the metal cylinder. And an electrode formed on the surface of the piezoelectric layer. 2. A hydrothermal synthesis method in which the main component of a hollow metal cylinder is used as one synthesis element in the presence of high-temperature and high-pressure water,
The method according to claim 1, wherein the piezoelectric layer is formed directly on the surface of the metal cylinder through a nucleation step and a crystal growth step. 3. A hydrothermal synthesis method comprising treating a mixture of a lead nitrate aqueous solution and a zirconium oxychloride aqueous solution having a predetermined lead: zirconium molar ratio with a potassium hydroxide 8N aqueous solution as a treatment liquid. A nucleation step of immersing a hollow metal cylinder made of titanium in a treatment liquid and nucleating lead zirconate titanate for a certain period of time in a closed atmosphere at about 150 ° C., and a predetermined lead: zirconium: titanium molar ratio A mixed solution obtained by adding a 4N aqueous solution of potassium hydroxide to a mixed solution of an aqueous solution of lead nitrate, an aqueous solution of zirconium oxychloride and an aqueous solution of titanium tetrachloride having the above is used as a treatment solution. 3. The method for manufacturing a piezoelectric element according to claim 2, further comprising a crystal growth step of performing crystal growth of lead zirconate titanate for a predetermined time in a sealed atmosphere around C. 4. A method in which a thin film for preventing the formation of a piezoelectric layer is formed in advance on the outer peripheral surface of a hollow metal cylinder, and the piezoelectric layer is formed directly on the inner peripheral surface of the hollow metal cylinder by a hydrothermal synthesis method. The method for manufacturing a piezoelectric element according to claim 2 or 3, wherein: 5. The method according to claim 2, wherein both ends of the hollow metal cylinder are plugged, and a piezoelectric layer is formed directly on the outer peripheral surface of the metal cylinder by hydrothermal synthesis in this state. The manufacturing method of the piezoelectric element according to the above. 6. A piezoelectric layer made of lead zirconate titanate by hydrothermal synthesis on the surface of a titanium film formed on a rod-shaped plastic material by laminating a platinum film and a titanium film on the outer peripheral surface thereof. 4. The method for manufacturing a piezoelectric element according to claim 2, wherein the rod-shaped plastic material is calcined and removed by heating the entirety in a lead vapor atmosphere.