KR100366767B1 - A method for manufacturing a piezo-electric actuator - Google Patents

Abstract

The piezoelectric actuator manufacturing method in the inkjet printer head of the present invention uses the finite element method to depend on the piezoelectric constant, electric field dependence, the plane size of the structure, the dependence on the aspect ratio, the width ratio and thickness of the piezoelectric film and the diaphragm. It is a piezoelectric actuator manufacturing method that can increase the center displacement of the diaphragm by identifying the dependence on the diaphragm. By the piezoelectric actuator manufacturing method as described above, a larger displacement of the center of the diaphragm can be obtained, thereby lowering ink discharge voltage and further reducing the size of the diaphragm.

Description

Piezoelectric actuator manufacturing method {A METHOD FOR MANUFACTURING A PIEZO-ELECTRIC ACTUATOR}

TECHNICAL FIELD The present invention relates to piezoelectric inkjet printer heads and, more particularly, to a method of manufacturing piezoelectric actuators in a more optimized inkjet printer head.

Fig. 1 (a) is a front view of a general piezoelectric actuator, and Fig. 1 (b) is a sectional view of a general piezoelectric actuator.

As shown in Figs. 1A and 1B, a chamber 6 in which ink is stored and one side of the chamber 6 form a diaphragm 1. The first electrode 3 for applying an electric field is formed on the diaphragm 1, and the piezoelectric element 2 is formed thereon. In addition, when the second electrode 4 for applying an electric field is formed on the piezoelectric body 2 and a voltage is applied to the first electrode 3 and the second electrode 4, the shape of the piezoelectric body 2 changes and the diaphragm 1 ), The ink in the chamber 6 is ejected through the nozzle 7. Therefore, in order to manufacture a piezoelectric actuator having excellent performance, when the electric field is applied through the first electrode 3 and the second electrode 4, the ink in the chamber 6 must be ejected accurately, so that the displacement of the center of the diaphragm 1 Should be large.

At this time, the width direction is the X-axis direction, the length direction is the Y-axis direction, and the thickness direction is the Z-axis direction.

European Patent 0 659 562 A2 describes a method for forming a piezoelectric actuator in an inkjet printer head using the lamination method of ceramic and metal plate for such a structure. In US Pat. No. 4,525,728, ink ejection characteristics according to various design variables in piezoelectric actuator formation in an inkjet printer head were analyzed using a simple bimorph equation such as Equation 1 below.

(δ: center displacement of vibration plate, l : length of vibration plate, d ₃₁ : piezoelectric constant, E3: electric field, Tp: piezoelectric thickness)

At this time, g (m, n) is a function as shown in Equation 2 below.

(m: ratio of elastic modulus of piezoelectric body to vibration plate, n: ratio of thickness of piezoelectric body to vibration plate)

On the other hand, Japanese Unexamined Patent Publication No. 8-252914 changed the material of the diaphragm 1 to use a single crystal material such as silicon in ceramic, and the piezoelectric material 2 also used a thin film process. In Japanese Patent Application Laid-Open No. 8-267738, U.S. Patent 4,525,728 sets the piezoelectric body 2, the diaphragm 1, and the first and second electrodes 3 and 4 to have the same planar dimensions, and compared with the head drive analysis. For the displacement of the large diaphragm 1, the ratio of the width of the first and second electrodes 3 and 4 to the width of the pressure chamber 6 was set from 0.6 to 0.7.

However, U.S. Patent 4,525,728 is only a qualitative analysis since the analysis is based on bimorph, which is a big difference from the actual shape of the inkjet printer head. That is, in the bimorph equation of Equation 1, the length of the diaphragm 1 means the length of a cantilever in the shape of a diving platform, and as shown in FIGS. 1 (a) and 1 (b), Since the actual shape is a form in which the diaphragm 1 is all connected to the chamber 6 and moving, the analysis using Equation 1 causes an error.

In addition, since the elastic modulus of the diaphragm 1 is applied to one, the elastic modulus of the diaphragm 1 is not applicable to the case where the modulus of elasticity is different depending on the direction.

In addition, U.S. Patent 4,525,728 only makes optimizations for specific materials such as zirconium oxide and PZT-based piezoelectric body 2 in determining the thickness ratio of the piezoelectric body 2 and the diaphragm 1, and the optimization is the piezoelectric body 2 Since the thickness of the diaphragm 1 is fixed because of optimization, it cannot be applied when the thickness of the diaphragm 1 is fixed.

Japanese Patent Laid-Open No. 8-267738 sets the ratio of the width of the first and second electrodes 3 and 4 to the width of the pressure chamber 6 from 0.6 to 0.7, but the width of the piezoelectric body 2 is almost the width of the pressure chamber 6. In this case, when the width of the piezoelectric body 2 itself is reduced, there is a problem in that the optimum conditions are required when the widths of the first and second electrodes 3 and 4 are changed.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and in the method of forming a piezoelectric actuator in an inkjet printer head, the piezoelectric body 2, the diaphragm 1, the first and second electrodes 3, 4, and the like are provided. It is to provide a piezoelectric actuator manufacturing method for optimizing to obtain a larger center displacement of the diaphragm (1).

1A is a front view of a general piezoelectric actuator.

Fig. 1 (b) is a sectional view of a general piezoelectric actuator.

Fig. 2 shows the center displacement of the diaphragm with respect to the area of the diaphragm.

3 shows the center displacement of the diaphragm according to the width ratio of the piezoelectric body and the diaphragm.

4 shows the center displacement of the diaphragm according to the aspect ratio of the diaphragm.

5 shows the center displacement of the diaphragm according to the thickness of the diaphragm when the ratio of the thickness of the piezoelectric body to the thickness of the diaphragm is made constant.

6 shows the center displacement of the diaphragm according to the thickness of the diaphragm when the thickness of the piezoelectric body is made constant.

7 shows the thickness of the piezoelectric body and the diaphragm center displacement in the case of a silicon substrate.

Fig. 8 shows the thickness of the diaphragm and the diaphragm center displacement when the maximum thickness of the piezoelectric body is determined.

Fig. 9 shows the optimum thickness ratio of the piezoelectric body and the diaphragm when the minimum thickness of the diaphragm is determined.

The piezoelectric actuator manufacturing method of the present invention for achieving the above object is dependent on the piezoelectric constant, electric field dependence, the plane size of the structure, the aspect ratio, the piezoelectric film and the like by using the finite element method. It is a piezoelectric actuator manufacturing method which can grasp | depend the dependence on the width ratio and thickness of the diaphragm 1, and can make center displacement of the diaphragm 1 larger.

A piezoelectric actuator manufacturing method according to an embodiment of the present invention includes the steps of: a) detecting the dependence of the piezoelectric constant of the piezoelectric body and the diaphragm center displacement on the electric field applied to the electrode; b) detecting the dependence of the diaphragm center displacement on the area of the diaphragm; c) detecting the dependence of the diaphragm center displacement on the ratio of the width of the piezoelectric member to the width of the diaphragm; d) detecting the dependence of the diaphragm center displacement on the aspect ratio of the diaphragm; e) fixing a ratio of the thickness of the piezoelectric body to the thickness of the diaphragm at a predetermined ratio, and detecting the dependence of the diaphragm center displacement on the thickness of the diaphragm while varying the thickness of the diaphragm; f) fixing the thickness of the piezoelectric body to a set thickness, and detecting the dependence of the diaphragm center displacement on the thickness of the diaphragm while varying the thickness of the diaphragm; g) detecting the dependence of the diaphragm center displacement on the thickness of the piezoelectric body; h) determining a maximum thickness of the piezoelectric body and detecting the dependence of the diaphragm center displacement on the maximum thickness of the piezoelectric body and the thickness of the diaphragm while varying the thickness of the diaphragm; i) determining a minimum thickness of the diaphragm and detecting the dependence of the diaphragm center displacement on the minimum thickness of the diaphragm and the thickness of the piezoelectric body while varying the thickness of the piezoelectric body; And j) determining the piezoelectric constant, width, thickness, and maximum thickness of the piezoelectric body based on the results detected in each step, and detecting the width, aspect ratio, thickness, and center of the diaphragm to produce the piezoelectric actuator. Include.

At this time, the center displacement of the diaphragm in the piezoelectric actuator manufacturing method according to the characteristics of the present invention has a linear proportionality with respect to the piezoelectric constant d ₃₁ and the electric field.

In the piezoelectric actuator manufacturing method according to the characteristics of the present invention, the center displacement of the diaphragm is proportional to the 1.9 power of the diaphragm length when the ratio of the thickness of the diaphragm to the width and length of the diaphragm is fixed and the area of the diaphragm is increased.

In the piezoelectric actuator manufacturing method according to the characteristics of the present invention, the center displacement of the diaphragm is fixed when the width of the diaphragm increases and the length of the diaphragm increases the aspect ratio of the diaphragm to almost the maximum value of 3: 1.

In the piezoelectric actuator manufacturing method according to the feature of the present invention, the center displacement of the diaphragm becomes maximum when the ratio of the width of the piezoelectric member to the width of the diaphragm is 0.72.

In the piezoelectric actuator manufacturing method according to the characteristics of the present invention, the center displacement of the diaphragm is characterized in that it is proportional to -0.9 power of the total thickness when the thickness ratio of the piezoelectric body and the diaphragm is fixed.

In the piezoelectric actuator manufacturing method according to the characteristics of the present invention, when the center displacement of the diaphragm is fixed to the thickness of the piezoelectric body, the area of the diaphragm, and the width ratio of the piezoelectric body to the width of the diaphragm, the ratio of the thickness of the piezoelectric body to the thickness of the diaphragm is 3.6. When it is set to the maximum.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The piezoelectric actuator fabrication method of the present invention comprises the steps of: a) detecting the dependence of the piezoelectric constant of the piezoelectric body and the diaphragm center displacement on the electric field applied to the electrode; b) detecting the dependence of the diaphragm center displacement on the area of the diaphragm; c) detecting the dependence of the diaphragm center displacement on the ratio of the width of the piezoelectric member to the width of the diaphragm; d) detecting the dependence of the diaphragm center displacement on the aspect ratio of the diaphragm; e) fixing a ratio of the thickness of the piezoelectric body to the thickness of the diaphragm at a predetermined ratio, and detecting the dependence of the diaphragm center displacement on the thickness of the diaphragm while varying the thickness of the diaphragm; f) fixing the thickness of the piezoelectric body to a set thickness, and detecting the dependence of the diaphragm center displacement on the thickness of the diaphragm while varying the thickness of the diaphragm; g) detecting the dependence of the diaphragm center displacement on the thickness of the piezoelectric body; h) determining a maximum thickness of the piezoelectric body and detecting the dependence of the diaphragm center displacement on the maximum thickness of the piezoelectric body and the thickness of the diaphragm while varying the thickness of the diaphragm; i) determining a minimum thickness of the diaphragm and detecting the dependence of the diaphragm center displacement on the minimum thickness of the diaphragm and the thickness of the piezoelectric body while varying the thickness of the piezoelectric body; And j) determining the piezoelectric constant, width, thickness, and maximum thickness of the piezoelectric body based on the results detected in each step, and detecting the width, aspect ratio, thickness, and center of the diaphragm to produce the piezoelectric actuator. Include.

At this time, in the present invention, the finite element method was used to model the piezoelectric actuator in the inkjet printer head to be close to the actual shape.

Looking at the relationship between the piezoelectric constant and the electric field and the center displacement of the diaphragm (1), the relationship between the piezoelectric constant and the center displacement of the diaphragm (1) is based on the piezoelectric constant ( The piezoelectric constant is the most important variable in the center displacement of the diaphragm 1 because of the various values.

Analysis using the finite element method showed a simple linear proportional relationship in the region where the center displacement of the diaphragm 1 was sufficiently smaller than the thickness of the membrane with respect to the piezoelectric constant and the electric field. Therefore, if any one set of variables is analyzed, the center displacement of the diaphragm 1 can be known by using a simple proportional relationship with respect to the piezoelectric constant or the electric field change.

Figure 2 shows the center displacement of the diaphragm with respect to the area of the diaphragm, which is the result of the step of grasping the relationship between the diaphragm area and the diaphragm center displacement.

At this time, in grasping the relationship of the center displacement of the diaphragm 1 with respect to the area of the diaphragm 1, the length and width of the diaphragm were 1.3 mm and 2.8 mm, respectively. ) And the thickness of the diaphragm 1 were made constant, and the ratio of the width | variety of the piezoelectric body 2 with respect to the width | variety of the diaphragm 1 was made constant. In addition, the aspect ratio of the diaphragm 1 was kept constant.

As shown in Fig. 2, under such conditions, the center displacement of the diaphragm 1 with respect to the area change of the diaphragm 1 while increasing or decreasing the area of the diaphragm 1 is analyzed using the finite element method. The bimorph equation is proportional to the square of the diaphragm length but is proportional to the 1.9 power of the linear regression result. That is, the central displacement of the diaphragm 1 when the length proportional constant is 10 is 10 ^1.9 times the central displacement of the diaphragm 1 when the length proportional constant is 1.

FIG. 3 shows the center displacement of the diaphragm 1 according to the ratio of the width of the piezoelectric element 2 to the width of the diaphragm 1, the width ratio of the piezoelectric element 2 and the diaphragm 1 and the center of the diaphragm 1. This is the result at the stage of grasping the displacement relationship of.

At this time, the length of the diaphragm is 1.3 mm and the length of 2.8 mm, respectively, and the thickness of the diaphragm and the piezoelectric body is 20 micrometers, respectively.

As shown in Fig. 3, the center displacement of the diaphragm 1 varies greatly depending on the ratio of the width of the piezoelectric element 2 to the width of the diaphragm 1. The center displacement of the diaphragm 1 continues to increase with this ratio, but when the ratio decreases rapidly after 0.72, when the width ratio reaches 1.2, only 2% of the maximum value is obtained.

In order for the center displacement of the diaphragm 1 to be large, the upper part of the diaphragm 1, which is not covered with the piezoelectric body 2, must be freely stretched as shown in FIG. 1, and the compressive stress is received by the piezoelectric body 2 as the width ratio increases. Therefore, the center displacement of the diaphragm 1 is reduced.

Therefore, in order to maximize the displacement of the diaphragm 1, the ratio of the width of the piezoelectric element 2 to the width of the diaphragm 1 should be optimized to 0.72.

FIG. 4 shows the change in the center displacement of the diaphragm 1 with respect to the change in the aspect ratio of the diaphragm 1, which is a result in the step of grasping the relationship between the aspect ratio of the diaphragm 1 and the center displacement of the diaphragm 1.

At this time, the thickness of the diaphragm and the piezoelectric body was 20 μm and 25 μm, respectively, and the width of the piezoelectric body 2 was 0.75 with respect to the width of the diaphragm 1, the width of the diaphragm was fixed at 1.3 mm, and only the length of the diaphragm was 1.3 mm. At 10.4 mm.

As shown in Fig. 4, when the length of the diaphragm 1 is slightly larger than the width, the center displacement of the diaphragm 1 increases rapidly, but once the length-to-width ratio is about 3: 1, it no longer increases. Therefore, when the aspect ratio becomes more than the volume change of the piezoelectric member 2 and the diaphragm 1, the center displacement of the diaphragm 1 is generally proportional to the length.

Therefore, in order to maximize the center displacement of the diaphragm 1, the aspect ratio of the diaphragm 1 should be optimized at 3: 1 or more.

5 shows the center displacement of the diaphragm 1 according to the thickness of the diaphragm 1, and when the thickness ratio of the piezoelectric body 2 and the diaphragm 1 is fixed, the thickness of the diaphragm 1 and the center of the diaphragm 1 are shown. This is the result at the stage of figuring out the relationship of displacement.

At this time, the length and width of the diaphragm are 1.3 mm and 2.8 mm, and the ratio of the width of the piezoelectric member 2 to the width of the diaphragm 1 is 0.75 and the thickness ratio of the diaphragm 1 and the piezoelectric member 2 is 1. The change of the center displacement was investigated by changing the thickness of the piezoelectric body and the diaphragm from 2.5 μm to 160 μm while maintaining the ratio at 1: 1.

As shown in FIG. 5, the bimorph equation of Equation 1 is proportional to the −1 power of the thickness, but when the linear regression is performed using the finite element method under the above conditions, the result is -0.9 power of the sum of the diaphragm and the piezoelectric thickness. Appears to be proportional to.

FIG. 6 shows the change of the center displacement of the diaphragm according to the thickness of the diaphragm. When the thickness of the piezoelectric body is constant, the result of the step of grasping the relationship between the center displacement of the diaphragm according to the thickness of the diaphragm is shown.

At this time, the size of the diaphragm 1 was 1.3 mm in width and 2.8 mm in length, and the thickness of the piezoelectric body 2 was 25 μm and the width ratio of the piezoelectric material 2 to the width of the diaphragm 2 was fixed at 0.75. . At this time, the elastic modulus ratio of the piezoelectric body to the diaphragm was 0.376.

As shown in Fig. 6, it can be seen that the displacement rapidly increases until the thickness ratio becomes 3.6, that is, until the thickness of the diaphragm 1 is 6.94 mu m, and then gradually decreases thereafter.

6 is a graph obtained by using the elastic modulus in the x-axis direction with the length of the diaphragm 1 being 1/2 the width of the diaphragm 1 in the bimorph equations such as the equations (1) and (2). The dotted line is a graph in which the length 1 of the diaphragm is calculated by 1/2 of the width of the piezoelectric body 2 in the equations (1) and (2).

The thickness ratio that makes the maximum displacement of the center of the diaphragm 1 is 3.1 in the case of the bimorph equations such as Equations 1 and 2, which is slightly different from 3.6, which is a result of analysis by the finite element method, but the diaphragm 1 is thick. The graph shows the bimorph diaphragm length being 1/2 of the piezoelectric body width in the region, and the diaphragm 1 was thin in the thin region, and the length was half the width of the diaphragm 1. .

Therefore, in order to maximize the center displacement of the diaphragm 1, the ratio of the thickness of the piezoelectric material 2 to the thickness of the diaphragm 1 should be 3.6. In addition, in the design of the planar actuator in which the edge of the diaphragm 1 is fixed, the displacement tendency can be simply recognized using the bimorph equation in the case of the thickness ratio.

FIG. 7 illustrates the relationship between the thickness of the piezoelectric body and the diaphragm center displacement, which is a result of determining the relationship between the thickness of the piezoelectric body and the diaphragm center displacement in the case of a silicon substrate.

In general, when the thickness ratio of the piezoelectric member and the diaphragm is constant, the displacement of the diaphragm increases as the overall thickness decreases as mentioned above, but when the piezoelectric actuator is manufactured using a silicon substrate, the diaphragm (1 Since it is difficult to freely reduce the thickness of the diaphragm, the minimum value of the thickness of the diaphragm 1 exists. Therefore, when the thickness of the piezoelectric element 2 is analyzed using the finite element method as shown in FIG. 7, when the ratio of the elastic modulus of the piezoelectric element to the diaphragm is 0.376, the diaphragm 2 is 1.25 times the thickness ratio of the piezoelectric element 2 to the diaphragm. 1) The maximum displacement of the center can be obtained.

Next, the method in the case of determining the displacement tendency by using the bimorph equation without using the finite element method will be described.

When the maximum thickness of the piezoelectric body is determined, it is a step of grasping the relationship between the thickness of the diaphragm and the diaphragm center displacement.

If the maximum thickness of the piezoelectric body 2 is determined due to process reasons or the like, the maximum displacement must be obtained by adjusting the thickness of the diaphragm 1. In this case, when the elastic modulus ratio m is determined due to the material, the thickness ratio n which gives the maximum displacement at that time is calculated from Equation 3 which differentiates Equation 1 from the thickness ratio n.

Among them, an equation having a positive solution for a positive m value is shown in Equation 4 below.

If the real root is selected, the following equation (5) can be obtained.

(even if m <1, not imaginary)

8 shows a graph according to equation (5).

Next, when the minimum thickness of the diaphragm is determined, the relationship between the piezoelectric thickness and the diaphragm center displacement is determined.

In the case of manufacturing the diaphragm 1 by etching the silicon substrate, the thickness of the piezoelectric element 2 is constant because the thickness of the diaphragm 1 is not limited to the thickness of the diaphragm 1. Since the equation 1 is not used, the following equation 6 should be optimized.

Therefore, in this case, The value of is a constant We need to find a condition to get the maximum of. In order to find such a condition, the following equation (7) is used.

Among them, an equation having a positive solution for a positive m value is shown in Equation 8 below.

Selecting the real root of this equation gives the following equation.

(If m <1, it's not an imaginary number.)

9 is a graph of equation (9).

Through these steps, the piezoelectric actuator can be manufactured under optimal manufacturing conditions.

This invention is capable of various modifications and implementations without departing from the scope of the following claims.

For example, in a structure such as an inkjet printer head, when a valve for controlling the flow of fluid is attached to the ink inlet and the nozzle, respectively, a volume change in the pressure chamber occurs due to the vibration of the piezoelectric actuator. Adjustable to one side, it is possible to construct a very small micro pump.

It also uses fuel for combustion instead of ink and attaches an ignition switch on the outside of the nozzle. And when the flame is applied to the fuel discharged through the nozzle by using the ignition switch, the fuel can be combusted. Since the fuel is continuously discharged in the form of fine droplets by the action of a continuous actuator, a flame is generated in the nozzle part and the flame is generated by the heater. Will be used. In this case, the size of the flame can be freely adjusted with a simple structure.

When the ink supply unit is used as a device for supplying a fluid sample such as blood or chemicals to be analyzed, and the nozzle part is connected to the sample analysis pressure chamber, the micros can be freely controlled and sent to each microanalysis pressure chamber. Analytical systems can be achieved.

As described above, the actuator optimized by the method of manufacturing the piezoelectric actuator according to the embodiment of the present invention can obtain a larger displacement, thereby lowering the ink discharge voltage, and reducing the size of the diaphragm at the same voltage, thereby providing a higher density inkjet printer. The manufacture of the head is possible.

Claims (12)

In the method of manufacturing a piezoelectric actuator comprising a piezoelectric body, a diaphragm and an electrode, a) detecting the dependence of the piezoelectric constant of the piezoelectric body and the diaphragm center displacement on the electric field applied to the electrode; b) detecting the dependence of the diaphragm center displacement on the area of the diaphragm; c) detecting the dependence of the diaphragm center displacement on the ratio of the width of the piezoelectric member to the width of the diaphragm; d) detecting the dependence of the diaphragm center displacement on the aspect ratio of the diaphragm; e) fixing a ratio of the thickness of the piezoelectric body to the thickness of the diaphragm at a predetermined ratio, and detecting the dependence of the diaphragm center displacement on the thickness of the diaphragm while varying the thickness of the diaphragm; f) fixing the thickness of the piezoelectric body to a set thickness, and detecting the dependence of the diaphragm center displacement on the thickness of the diaphragm while varying the thickness of the diaphragm; g) detecting the dependence of the diaphragm center displacement on the thickness of the piezoelectric body; h) determining a maximum thickness of the piezoelectric body and detecting the dependence of the diaphragm center displacement on the maximum thickness of the piezoelectric body and the thickness of the diaphragm while varying the thickness of the diaphragm; i) determining a minimum thickness of the diaphragm and detecting the dependence of the diaphragm center displacement on the minimum thickness of the diaphragm and the thickness of the piezoelectric body while varying the thickness of the piezoelectric body; And j) determining the piezoelectric constant, width, thickness, and maximum thickness of the piezoelectric body based on the results detected in each step, and detecting the width, aspect ratio, thickness, and center of the diaphragm to manufacture the piezoelectric actuator; Piezoelectric actuator manufacturing method comprising a. (Correction) The method according to claim 1, The a) to g) step is a piezoelectric actuator manufacturing method characterized in that using the finite element method. (Correction) The method according to claim 1 or 2, Steps a) and e) is a piezoelectric actuator manufacturing method characterized in that the linear regression after analyzing the dependence of the center displacement of each diaphragm by the finite element method. (Correction) The method according to claim 1 or 2, In the step a), the center displacement of the diaphragm with respect to the piezoelectric constant and the electric field in a region where the thickness of the diaphragm is smaller than the minimum set thickness is linearly proportional to the piezoelectric actuator manufacturing method. (Correction) The method according to claim 1 or 2, Step c) is The horizontal and vertical lengths of the diaphragm are fixed to a set length, and if the thickness of the diaphragm and the piezoelectric body is the same, the piezoelectric center is characterized in that the displacement of the center of the diaphragm becomes maximum when the ratio of the width of the piezoelectric body to the width of the diaphragm is 0.72. How to make an actuator. (Correction) The method according to any one of claims 1 to 3, Step b), When the area of the diaphragm is 1, the thickness of the piezoelectric body and the diaphragm is a set thickness, the ratio of the width of the piezoelectric body to the width of the diaphragm is set to a set ratio, and the aspect ratio of the diaphragm is fixed to a set ratio. The center displacement is a piezoelectric actuator manufacturing method, characterized in that proportional to 1.9 times the length of the diaphragm. (Correction) The method according to claim 1 or 2, In step d), When the thickness of the diaphragm and the piezoelectric body and the width of the piezoelectric body with respect to the width of the diaphragm are fixed to a set value, and the width of the diaphragm is fixed, the diaphragm center displacement is 3: 1 or more at a ratio of the width of the diaphragm to the length of the diaphragm. The piezoelectric actuator manufacturing method characterized in that the maximum. (Correction) The method according to any one of claims 1 to 3, In step e), The length of the diaphragm and the length of the diaphragm are fixed to a set length, the ratio of the thickness of the piezoelectric member to the thickness of the diaphragm is fixed at 1: 1, and the ratio of the piezoelectric width to the width of the diaphragm is set at a predetermined ratio. When fixed, the piezoelectric actuator manufacturing method characterized in that the center displacement of the diaphragm is proportional to the -0.9 power of the sum of the thickness of the diaphragm and the piezoelectric body. (Correction) The method according to claim 1 or 2, In step f), When the area of the diaphragm, the thickness of the piezoelectric body, and the width ratio of the piezoelectric body to the width of the diaphragm are fixed at a predetermined ratio, the center displacement of the diaphragm becomes maximum when the ratio of the piezoelectric thickness to the thickness of the diaphragm is 3.6. Method for producing a piezoelectric actuator, characterized in that. (Correction) According to claim 1 and 2, Step g), And the center displacement of the diaphragm becomes maximum when the elastic modulus ratio of the piezoelectric body to the diaphragm is 0.376 and the thickness ratio of the piezoelectric body to the diaphragm is 1.25. (Correction) The method according to claim 1, In step h), When the ratio of the elastic modulus of the piezoelectric to the elastic modulus of the diaphragm is determined, the thickness ratio of the piezoelectric to the thickness of the diaphragm satisfies the following conditions. (m: ratio of elastic modulus of piezoelectric body to vibration plate, n: ratio of thickness of piezoelectric body to vibration plate) (Correction) The method according to claim 1, Step i), And a relationship between the ratio of the elastic modulus of the piezoelectric body to the elastic modulus of the diaphragm and the thickness ratio of the piezoelectric body to the thickness of the diaphragm satisfies the following conditions. (m: ratio of elastic modulus of piezoelectric body to vibration plate, n: ratio of thickness of piezoelectric body to vibration plate)