JPH06312505A - Laminated type piezoelectric displacement element and ink jet record head using the same - Google Patents

Abstract

PURPOSE:To make a drive displacement at a central part equal to that at an end part so as to prevent occurrence of defective ink discharge by making length of inner electrode at the central side shorter than that at the end face, in an element having piezoelectric materials and electrodes laminated alternately. CONSTITUTION:In a laminated type piezoelectric displacement element 1, piezoelectric materials 2 and inner electrodes 3 are laminated alternately and an outer electrode 4 is laminated on the outside of the laminated body. The inner electrodes 3 are formed in such a manner that those inner electrodes near end faces 9, 10 of the element 1 are longer and the inner electrodes at the central part are shorter than the inner electrodes at the end faces 9, 10. Thus, at applying voltage, the piezoelectric displacement element 1 is changed uniformly from an end face 5 to an end face 6. Or, the laminated thickness of those piezoelectric materials 2 at the central side may be made to be thicker than that of those piezoelectric materials 2 at the end face side or a piezoelectric distortion constant of those piezoelectric materials 2 at the central side may be made to be smaller than that of those piezoelectric materials 2 at the end face side, so as to make drive potentials at the central part and the end part equal to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a laminated piezoelectric displacement element and a laminated piezoelectric displacement element used for an ink jet recording head of an ink jet recording apparatus.

[0002]

2. Description of the Related Art Conventionally, a piezoelectric displacement element made of a piezoelectric material has a function as a conversion element of electric energy and mechanical energy, and thus has been applied to fields such as actuators. Furthermore, in recent years, the driving voltage has been significantly reduced by using a piezoelectric displacement element of a laminated type. Japanese Patent Laid-Open No. 56-120 discloses a laminated piezoelectric displacement element.
In Japanese Patent No. 365, 365, there is disclosed a method of significantly reducing a driving voltage by using a laminated piezoelectric displacement element as an actuator of an inkjet recording head.

FIG. 23 shows a conventional example of a laminated piezoelectric displacement element. The laminated piezoelectric displacement element 11 has a structure in which a thin film-shaped internal electrode 13 having the same length in each layer is sandwiched between the layers of the piezoelectric material 12 laminated in a plurality of layers to form an external electrode 14 and exposed on one end face of the element. The electrodes 59 and 60 were connected to the external electrode 61 and a voltage 62 was applied to drive the displacement.

The laminated piezoelectric displacement element 1 as described above is also used.
When 1 is used as the actuator of the inkjet recording head, as shown in FIG. 24, the end surface 64 of the laminated piezoelectric displacement element 11 in the displacement direction 63 is attached to the pressure plate 23 and used as the actuator of the inkjet recording head. It was The pressure chambers 19 are separated by a flow path wall 22, and the pressure generated by the laminated piezoelectric displacement element 11 is applied to the pressure chambers 1.
A pressure plate 23 is formed for transmission to the gear 9. The ink passes through the ink flow path 20 and is ejected from the ink ejection nozzle 21. Although not shown in the figure, the laminated piezoelectric displacement element 11 is fixed, and the positional relationship with the pressure plate 23 is kept constant via a fixing plate or the like.

[0005]

However, in the prior art, as shown in FIG. 25, when the above-mentioned laminated piezoelectric displacement element 11 is driven in the d31 direction, it is displaced from the end face 15 to the end face 16 and the central portion Displacement amount 17 is end displacement amount 18
Was more than 50% larger. Therefore, when the conventional laminated piezoelectric displacement element 11 is used in a piezoelectric actuator, if the pressure-sensitive body and the laminated piezoelectric displacement element 11 come into contact with each other within a range smaller than the end surface 15 of the laminated piezoelectric displacement element, the laminated type There is a problem that the amount of displacement applied to the body to be pressured differs greatly depending on whether the piezoelectric displacement element is in contact with the central portion or the end portion.

Therefore, in order to efficiently transmit the maximum displacement of the laminated piezoelectric displacement element 11 to the body to be pressured, it is necessary to accurately attach the portion showing the maximum displacement amount 17 in the central portion to the body to be pressured. It was In the example of the ink jet recording head, when the mounting positions of the laminated piezoelectric displacement element 11 and the pressure plate 23 are deviated, the laminated piezoelectric displacement element 11 and the pressure plate 2 are moved.
The displacement amount applied to 3 is a small displacement amount on the end face side, and the maximum displacement amount is not transmitted to the pressure plate 23 of the ink flow path. When the above situation occurs, a situation such as defective ink ejection of the ink jet recording head or inability to print occurs. Therefore, alignment adjustment work is required, and the cost of the ink jet recording head is increased in the manufacturing process. In particular, in the field of ink jet recording heads, which have been rapidly increased in density in recent years, it is inevitable to miniaturize the laminated piezoelectric displacement element, and the displacement of the piezoelectric displacement element or the laminated piezoelectric displacement element can be accurately performed. A large amount of time and labor was spent on the adjustment work for the alignment in order to transmit the pressure plate to the ink flow path.

The present invention is intended to solve the above-mentioned problems, and an object of the present invention is to make driving displacement of a laminated piezoelectric displacement element substantially equal at a central portion and an end portion thereof so that the piezoelectric displacement element is It is an object of the present invention to provide a laminated piezoelectric displacement element capable of significantly improving the problem that the amount of displacement applied to a pressure-sensitive body varies depending on the contact position with the pressure body, and an inkjet recording head having no ink ejection failure.

[0008]

The laminated piezoelectric displacement element of the present invention is a laminated piezoelectric displacement element in which piezoelectric materials and internal electrodes are alternately laminated, and the calculated displacement amount of the unit layer in the d31 direction is from the end face side. Is also characterized by being smaller on the central side.

In order to realize the above-mentioned distribution of the calculated displacement amount of the unit layer, in the laminated piezoelectric displacement element of the present invention, the internal electrode length on the central portion side is shorter than the internal electrode length on the end face side. Shorter, or thicker the laminated thickness of the piezoelectric material on the central portion side than the laminated thickness of the piezoelectric material on the end face side, or
It is characterized in that the piezoelectric strain constant of the piezoelectric material on the central portion side is smaller than the piezoelectric strain constant of the piezoelectric material on the end face side.

[0010]

According to the laminated piezoelectric displacement element of the present invention, the difference in driving displacement between the central portion and the end portion can be made smaller than in the conventional case, and a displacement surface parallel to the end surface before displacement can be obtained. Even when the contact position with the body is different, it is possible to apply a constant amount of displacement and pressure to the body to be pressured.

[0011]

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 7 show the first structure of the laminated piezoelectric displacement element of the present invention. In FIG. 1, reference numeral 1 is a laminated piezoelectric displacement element, which is composed of a piezoelectric material 2, an internal electrode 3, and an external electrode 4. The inner electrode 3 is longer near the end faces 9 and 10 of the laminated piezoelectric displacement element 1, and the inner electrode at the center is shorter than the inner electrodes on the end faces 9 and 10 side. As shown in FIG. 2, the laminated piezoelectric displacement element 1 is
By applying a voltage, the end surface 5 is uniformly changed to the end surface 6. Actually, the difference between the displacement amount 7 at the central portion and the displacement amount 8 at the end portion of the laminated piezoelectric displacement element 1 showed a uniform displacement amount within 20%. The calculated displacement amount of the unit layer of the laminated piezoelectric displacement element of the present invention is smaller on the central portion side than on the end face 9 and 10 side, but the actual displacement amount is on the end face side due to stress or the like acting in the element. And it was possible to make it uniform on the central side.

Here, the calculated displacement amount L is a value represented by the following equation.

[0014]

[Equation 1]

K is a piezoelectric strain constant in the d31 direction and is a value determined by the piezoelectric material. “A” indicates the length of the active portion, which is a value determined by the overlapping length of the upper and lower internal electrodes.
t represents a laminated thickness, which is a value determined by the thickness of the piezoelectric material sandwiched between the internal electrodes. V indicates an applied voltage.

In the above embodiment, the internal electrode length on the central portion side is made shorter than the internal electrode length on the end surface side of the laminated piezoelectric displacement element, and the active portion length on the central portion side is made smaller than the active portion length on the end face side. is doing. As a result, the calculated displacement amount L of the unit layer in the d31 direction is smaller on the central portion side than on the end face side of the laminated piezoelectric displacement element.

The laminated piezoelectric displacement element 1 of FIG. 1 is characterized in that the length of the internal electrode 3 is shorter in the central portion side than in the end face side of the laminated piezoelectric displacement element 1. For example, FIG.
, A plurality of inner electrodes 33 and 34 of the same length are shown in FIG.
Even if there is such a structure, the structure may be such that the length of the internal electrode 3 becomes shorter toward the central portion like the laminated piezoelectric displacement element 1 of FIG.

In FIG. 4, between the internal electrodes 35 and 36 adjacent to each other, the internal electrode 35 on the end face side is shorter than the internal electrode 36 on the central portion side. Any structure may be used as long as the internal electrodes of the section are shortened. Furthermore, as shown in FIGS. 5, 6 and 7, the internal electrodes 37 on one side have the same length, but the internal electrodes 3 on the other side have a shorter internal electrode 3 in the central portion. If

A method of manufacturing the laminated piezoelectric displacement element having the first structure of the present invention shown in FIGS. 1 to 7 will be described with reference to FIG. 8 (a) to 8 (e) show a process of alternately stacking piezoelectric materials and internal electrodes.

As shown in FIG. 8A, first, the piezoelectric material 2
The raw sheet 38 of the piezoelectric material is formed. Next, as shown in FIG. 8B, the electrode paste 39 of the internal electrodes 3 is printed on the piezoelectric green sheet 38. Next, as shown in FIG. 8C, the piezoelectric green sheet 38 is laminated on the electrode paste 39, and the electrode paste 4 which is the other electrode is further laminated thereon.
0 is printed, and the piezoelectric green sheet 3 is placed on the electrode paste 40.
Print 8. Next, as shown in FIG. 8D, the electrode paste 41 is printed on the piezoelectric green sheet 38. The electrode paste 41 is printed so as to be shorter than the electrode paste 39. By repeating the lamination of the piezoelectric body green sheet and the printing of the electrode paste as described above, a laminated body 42 of the piezoelectric body green sheet and the electrode paste as shown in FIG. 8E is manufactured. At this time, the electrode green paste printed on the piezoelectric green sheet is manufactured in units of the piezoelectric green sheet of each piezoelectric material,
Finally, each piezoelectric green sheet may be laminated.

Then, the laminated body 42 of the piezoelectric green sheet and the electrode paste is thermocompression bonded, then sintered at a high temperature of about 1000 ° C., and finally the external electrode 7 is formed to form the laminated piezoelectric displacement of the present invention. The device can be manufactured. As the external electrode 7, a thin film electrode is formed by sputtering or vapor deposition, or a thick film electrode is formed by a conductive adhesive.

As the piezoelectric material, piezoelectric materials having different piezoelectric strain constants were appropriately selected from PZT system such as lead titanate-lead zirconate. Piezoelectric green sheets are prepared by first sintering the piezoelectric material into powder, mixing it with an organic binder, plasticizer, dispersant, and solvent to make a slurry, and then attaching the slurry to a roller and making it thick with a blade. The material was transferred evenly in size, punched into a certain size, and dried to obtain a piezoelectric green sheet. The electrode paste was appropriately selected or mixed from silver, palladium, platinum, etc., and mixed with a solvent and a binder before use.

The laminated piezoelectric displacement element used in this embodiment is
The thickness of the piezoelectric material is 0.05 mm per layer, and the internal electrode 3
Has a thickness of 0.005 mm, and the internal electrodes are approximately 0.2 mm above and below
The length is different for each. The upper and lower overlapping widths of the internal electrodes 3 are 5 mm for the internal electrodes on the end face side. Piezoelectric material 2 d3
The piezoelectric strain constant in one direction is 300 × 10 ⁻¹² (m / V).

A laminated piezoelectric displacement element having a second structure according to the present invention will be described with reference to FIG. The laminated piezoelectric displacement element 1 includes a piezoelectric material 2, an internal electrode 3, and an external electrode 4.
The feature of this configuration is that the laminated thickness of the piezoelectric material 2 is thinner as it is closer to the end faces 9 and 10 of the laminated piezoelectric displacement element 1, and the laminated thickness at the center is thicker than the laminated thickness at the end faces 9 and 10 side. It has become.

The distribution of the laminated thickness of the piezoelectric material 2 of this embodiment is shown in FIG. The laminated thickness is distributed such that the thickness gradually increases from the end face side toward the central portion side. Further, the laminated thickness of the piezoelectric material is thinner on the end face side than on the central portion side.

According to this structure, the calculated displacement amount L of the unit layer in the d31 direction is smaller on the central portion side than on the end face side of the laminated piezoelectric displacement element, which is the same as the laminated piezoelectric displacement element of the first constitution. Similar displacements are shown.

In the laminated piezoelectric displacement element of FIG. 9, the distribution of the lamination pressure is gradually increased toward the central portion, but as shown in FIG. 11, a plurality of identical lamination thicknesses 43 and 44 are present. Even in the distribution, as shown in FIG. 12, in the adjacent laminated thicknesses 45 and 46, the laminated thickness 45 on the end face side is thicker than the laminated thickness 46 on the central side, but the piezoelectric material It is sufficient that the entire laminated thickness is such that the end face side is thin.

A method of manufacturing the second structure of the laminated piezoelectric displacement element of the present invention will be described below.

The manufacturing method of the laminated piezoelectric displacement element having the second structure is the same step up to FIG.
As shown in (a), a piezoelectric raw sheet 47 thicker than the piezoelectric raw sheet 38 is laminated on the electrode paste 39.
Next, the electrode paste 40 for the other internal electrode is printed on the piezoelectric green sheet 47. By the above operation, FIG.
As shown in FIG. 1 (c), the laminated body 6 of the piezoelectric green sheet and the electrode paste in which the laminated thickness of the piezoelectric green sheet is thicker in the central portion
5 is manufactured. The subsequent steps of sintering and attaching external electrodes were performed in the same manner as in the first structure of the laminated piezoelectric displacement element.

The laminated piezoelectric displacement element used in this embodiment is
The thickness of the piezoelectric material is 0.02 mm, 0.03 from the end face side.
mm, 0.04 mm, and 0.05 mm, and the laminated thickness of the piezoelectric material 2 is thinner toward the end face side. Internal electrode 3
Has a thickness of 0.005 mm. Inner electrode 3 overlapping width 5 above and below
mm. The piezoelectric strain constant of the piezoelectric material 2 in the d31 direction is 300 ×
It is 10 ⁻¹² (m / V).

The third structure of the laminated piezoelectric displacement element of the present invention will be described below with reference to FIG.

The laminated piezoelectric displacement element 1 includes a piezoelectric material 48,
49, 50, 51, the internal electrode 3, and the external electrode 4. The piezoelectric strain constant of the piezoelectric material is 48, 49, 5 from the side closer to the end faces 9 and 10 of the laminated piezoelectric displacement element 1.
The piezoelectric material laminated on the central portion side is smaller than the piezoelectric material on the end faces 9 and 10 in this order.

The distribution of the piezoelectric strain constant of the piezoelectric material is shown in FIG. The piezoelectric strain constants are distributed so as to increase from the central portion side toward the end face side.

According to this structure, the calculated displacement amount L of the unit layer in the d31 direction is smaller on the central portion side than on the end face side of the laminated piezoelectric displacement element, which is the same as the laminated piezoelectric displacement element of the first constitution. Similar displacements are shown.

Further, the laminated piezoelectric displacement element of FIG. 14 is characterized in that the piezoelectric strain constant of the piezoelectric material is larger on the end face side than on the central portion side. For example, as shown in FIG. The distribution may be such that piezoelectric materials 52 and 53 having the same piezoelectric strain constant exist.

Further, as shown in FIG. 17, the inside of the laminated piezoelectric displacement element is made of a piezoelectric material 54 having the same piezoelectric strain constant, and the end face side is made of a piezoelectric material 55 having a larger piezoelectric strain constant than the piezoelectric material 54. It may be configured.

The manufacturing method of the third structure of the laminated piezoelectric displacement element of the present invention is the same as the manufacturing method of the first structure of the present invention.

The laminated piezoelectric displacement element used in this embodiment is
The thickness of each piezoelectric material 48, 49, 50, 51 is 0.05 mm per layer, and the thickness of the internal electrode 3 is 0.005 m.
m, the upper and lower overlapping width of the internal electrode 3 is 5 mm, the piezoelectric material 4
The piezoelectric strain constants in the d31 direction of 8, 49, 50 and 51 are 400 × 10 ⁻¹² , 340 × 10 ⁻¹² and 300 ×, respectively.
It is 10 ⁻¹² , 260 × 10 ⁻¹² (m / V).

As described above, in the laminated piezoelectric displacement element of the present invention, the calculated displacement amount of the unit layer in the d31 direction is smaller on the central portion side than on the end face side. The internal electrode length on the central portion side is shorter than the internal electrode length (first configuration), or the laminated thickness of the piezoelectric material on the central portion side is larger than the laminated thickness of the piezoelectric material on the end face side. Is thick (second configuration), or the piezoelectric strain constant of the piezoelectric material on the central side is smaller than the piezoelectric strain constant of the piezoelectric material on the end face side (third configuration).

Next, an ink jet recording head using the laminated piezoelectric displacement element of the present invention will be described.

FIG. 18 is a schematic view of an ink ejection portion of an ink jet recording head using the laminated piezoelectric displacement element of the present invention. The pressure chamber 19 is a portion for obtaining pressure for ejecting ink by the laminated piezoelectric displacement element 1. The ink passes through the ink flow path 20 and is ejected from the ink ejection nozzle 21. Each pressure chamber 19 is separated by a flow path wall 22, and a pressure plate 23 for transmitting the displacement of the laminated piezoelectric displacement element 1 to the pressure chamber 19 is formed. Although not shown in the figure, the laminated piezoelectric displacement element 1 of the present invention is fixed, and the positional relationship with the pressure plate 19 is kept constant via a fixing plate or the like.

The principle of ink ejection pressure generated from the laminated piezoelectric displacement element 1 will be briefly described. The laminated piezoelectric displacement element 1 is displaced from the end surface 5 to the end surface 6 as shown in FIG. 2 by applying a voltage. At this time, the pressure chamber 19 is slowly displaced so that the behavior of the ink does not change. Next, when the applied voltage is rapidly released, the end face 6 rapidly returns to the position of the end face 5. Therefore, the displacement amount and the displacement speed from the end face 6 to the end face 5 when the applied voltage is rapidly released are used as the ink ejection pressure.

As shown in FIG. 19, when the laminated piezoelectric displacement element 1 of the present invention was installed right above the pressure plate 19 and was used as an actuator of an ink jet recording head for printing, ink ejection amount and ink ejection were performed. It was possible to obtain a very clear and beautiful printed matter with little variation in speed. Therefore, it can be seen that the pressure when driven by applying a voltage is normally transmitted to the pressure plate 23.

The specifications of the laminated piezoelectric displacement element and the specifications of the ink jet recording head used in this example are shown below.
Drive voltage 50V. Pressure chamber 10, width 0.2 mm x length 1 m
m × height 0.4 mm. Channel wall 13, width 0.6 mm x length 1 mm x height 0.4 mm. Ink discharge nozzle 12, nozzle diameter 0.04 mm, member thickness 0.1 mm.

Further, as shown in FIG. 20, even when the laminated type piezoelectric displacement element 1 of the present invention is installed so that the center 26 is outside the surface 27 of the pressure plate 23, the actuator of the ink jet recording head is provided. As a result of printing, it was possible to obtain a very clear and beautiful printed matter with little variation in the ink ejection amount and the ink ejection speed. Further, since the difference in displacement amount between the central portion and the end portion of the laminated piezoelectric displacement element 1 is small, even if the center 26 is outside the surface 27 of the pressure plate 23, pressure is normally applied to the pressure plate 23. I understand that it is being done.

The results of comparison between the ink jet recording head using the laminated piezoelectric displacement element of the present invention and the ink jet recording head using the conventional laminated piezoelectric displacement element are shown below.

FIG. 21 is a diagram in which the abscissa plots the amount of ink drops and the ordinate plots the number of ink drops to compare variations in the amount of ink drops ejected from the ink ejection nozzles 21. A curve 24 showing the distribution of the amount of ink droplets ejected from the inkjet recording head using the laminated piezoelectric displacement element of the present invention is the amount of ink droplets ejected from the inkjet recording head using the conventional laminated piezoelectric displacement element. Curve 25 showing the distribution
It can be seen that the variation in the ink droplet amount is smaller than that of More specifically, in curve 24, 0.09 to 0.
In the range of 11 mg, about 80% of the ink droplets are included, whereas in the curve 25, about 5% of the ink droplets are included.
It was 0%. Therefore, it is understood that the use of the laminated piezoelectric displacement element of the present invention can control the variation in the print density to be small.

FIG. 22 is a diagram comparing the positional relationship between the element center and the pressure plate and the ink ejection pressure. A curve 29 shows the distribution of the ink ejection pressure when the laminated piezoelectric displacement element 1 of the present invention is used. A curve 30 shows the distribution of the ink ejection pressure when the conventional laminated piezoelectric displacement element 11 is used.
When the position of the center 28 of the conventional laminated piezoelectric displacement element 11 deviates from the width 31 (0.5 mm) of the surface 27 of the pressure plate 23, the ink ejection pressure sharply decreases, but the laminated piezoelectric displacement element 1 of the present invention The center 26 of the pressure plate 23 is the width 31 of the surface 27 of the pressure plate 23.
Distance 32 at which the ink ejection pressure does not change even when
It was found that (0.2 mm) was present. Therefore, in order to keep the ink ejection pressure constant, the center 28 of the conventional laminated piezoelectric displacement element 11 is arranged at the width 31 of the surface 27 of the pressure plate 23.
It is necessary to mount within the range of, and the mounting position of the center 26 of the laminated piezoelectric displacement element 1 of the present invention may be mounted within a range in which the distance 32 is more allowable than the width 31.

Although the embodiment of the laminated piezoelectric displacement element of the present invention has been described above by taking the ink jet recording head as an example, the laminated piezoelectric displacement element of the present invention is specialized for an ink jet recording head. is not. because,
The present invention solves the problem common to conventional piezoelectric displacement elements and laminated piezoelectric displacement elements that the amount of displacement differs between the central portion and the end portion. It can be applied in a wide range as a piezoelectric actuator used for the purpose of adding to.

[0050]

As described above, according to the present invention, it has been found that the laminated piezoelectric displacement element is displaced in the shape of the end surface parallel to the end surface before the displacement. Therefore, when the laminated piezoelectric displacement element of the present invention is used in a piezoelectric actuator, it is possible to apply a stable displacement and pressure without being influenced by the mounting position of the body to be pressured. This solves the problem that in the conventional piezoelectric displacement element and laminated piezoelectric displacement element, the displacement amount is larger in the central portion than in the end portions of the element, and in order to obtain a stable displacement amount and pressure. In addition, the enormous amount of time and labor required for adjusting the mounting positions of the laminated piezoelectric displacement element and the body to be pressured is significantly improved.

Further, when the laminated piezoelectric displacement element of the present invention was applied to the actuator of the ink jet recording head, it was found that the force applied to the pressure plate of the ink jet recording head was stable due to the displacement. Furthermore, since the laminated piezoelectric displacement element is displaced from the pressure plate, normal ink ejection can be performed by using the laminated piezoelectric displacement element of the present invention even in an ink jet recording head that has conventionally been defective in ink ejection. It became possible. Due to the above effects, when the laminated piezoelectric displacement element of the present invention is used for an actuator of an ink jet recording head, the defect occurrence rate in the manufacturing process is improved, and a significant cost reduction can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing a first configuration of a laminated piezoelectric displacement element of the present invention.

FIG. 2 is a diagram showing a displacement shape of the laminated piezoelectric displacement element of FIG.

FIG. 3 is a diagram showing a first configuration of a laminated piezoelectric displacement element of the present invention.

FIG. 4 is a diagram showing a first configuration of a laminated piezoelectric displacement element of the present invention.

FIG. 5 is a diagram showing a first configuration of the laminated piezoelectric displacement element of the present invention.

FIG. 6 is a diagram showing a first configuration of a laminated piezoelectric displacement element of the present invention.

FIG. 7 is a diagram showing a first configuration of the laminated piezoelectric displacement element of the present invention.

FIG. 8 is a diagram showing a manufacturing method of the first configuration of the laminated piezoelectric displacement element of the present invention.

FIG. 9 is a diagram showing a second configuration of the laminated piezoelectric displacement element of the present invention.

FIG. 10 is a diagram showing a stack thickness distribution of the piezoelectric material of the second structure of the stack type piezoelectric displacement element of the present invention.

FIG. 11 is a diagram showing a stack thickness distribution of the piezoelectric material of the second configuration of the stack type piezoelectric displacement element of the present invention.

FIG. 12 is a diagram showing a stack thickness distribution of the piezoelectric material of the second structure of the stack type piezoelectric displacement element of the present invention.

FIG. 13 is a diagram showing a method of manufacturing the second configuration of the laminated piezoelectric displacement element of the present invention.

FIG. 14 is a diagram showing a third configuration of the laminated piezoelectric displacement element of the present invention.

FIG. 15 is a diagram showing the distribution of the piezoelectric strain constant of the piezoelectric material of the third configuration of the laminated piezoelectric displacement element of the present invention.

FIG. 16 is a diagram showing the distribution of the piezoelectric strain constant of the piezoelectric material of the third structure of the laminated piezoelectric displacement element of the present invention.

FIG. 17 is a diagram showing the distribution of the piezoelectric strain constant of the piezoelectric material of the third configuration of the laminated piezoelectric displacement element of the present invention.

FIG. 18 is a diagram in which the laminated piezoelectric displacement element of the present invention is used in an actuator of an inkjet recording head.

19 is a diagram showing a positional relationship between the laminated piezoelectric displacement element and the pressure plate in FIG.

20 is a diagram showing a positional relationship between another laminated piezoelectric displacement element and a pressure plate in FIG.

FIG. 21 is a diagram comparing the ink discharge amount variations of the inkjet recording head of the present invention and the conventional inkjet recording head.

FIG. 22 is a diagram comparing the ink discharge pressure depending on the positional relationship between the center of the laminated piezoelectric displacement element and the pressure plate between the present invention and the conventional laminated piezoelectric displacement element.

FIG. 23 is a view showing a conventional laminated piezoelectric displacement element.

FIG. 24 is a diagram in which a conventional laminated piezoelectric displacement element is used in an inkjet recording head.

FIG. 25 is a diagram showing a displacement shape of the laminated piezoelectric displacement element of FIG. 23.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multilayer piezoelectric displacement element 2 Piezoelectric material 3 Internal electrode 4 External electrode 5,6 End face 7,8 Displacement amount 9, 10 End face 19 Pressure chamber 20 Ink flow passage 21 Ink ejection nozzle 22 Ink flow passage wall 23 Pressure plate

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01L 41/04 9274-4M 41/09

Claims (5)

[Claims] 1. A laminated piezoelectric displacement element in which piezoelectric materials and electrodes are alternately laminated, wherein the calculated displacement of the unit layer in the d31 direction is smaller on the central side than on the end face side. Type piezoelectric displacement element. 2. The laminated piezoelectric displacement element according to claim 1, wherein the electrode length on the central side is shorter than the electrode length on the end face side. 3. The laminated piezoelectric displacement element according to claim 1, wherein the laminated thickness of the piezoelectric material on the central side is thicker than the laminated thickness of the piezoelectric material on the end face side. 4. The laminated piezoelectric displacement element according to claim 1, wherein the piezoelectric strain constant of the piezoelectric material on the central side is smaller than the piezoelectric strain constant of the piezoelectric material on the end face side. 5. A nozzle and a pressure chamber communicating with the nozzle,
An inkjet recording head having a pressure generating means for applying a pressure for ejecting ink to a pressure chamber, wherein the laminated piezoelectric displacement element according to claim 1, 2, 3 or 4 is used as the pressure generating means. Inkjet recording head.