JPH0677555A - Method for manufacturing laminated piezoelectric element - Google Patents

Abstract

PURPOSE:To provide a manufacturing method of laminated piezoelectric element capable of cutting down the manufacturing cost thereof not requiring of so strict green sheet control. CONSTITUTION:Green sheets are baked to form ceramic sheets. Next, the ceramic sheets are polished to form respective electrodes on both main surfaces of the ceramic sheets. Furthermore, a glass layer is formed on one main surface of the ceramic sheets to bond multiple ceramic sheets for the formation step of a laminated body. Next, the multiple ceramic sheets are polarization- processed. Besides, during the formation step of the laminated body, it is recommended that the multiple ceramic sheets are to be pressure-fixed by applying a load. On the other hand, the thickness of the glass layer not exceeding 1mum is preferable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a laminated piezoelectric element, and more particularly, to a laminated piezoelectric actuator using a laminated piezoelectric actuator, a piezoelectric oscillator, a piezoelectric filter or the like, which utilizes a vibration mode of a second or higher order. The present invention relates to a method for manufacturing a laminated piezoelectric element such as a resonance element.

[0002]

2. Description of the Related Art Conventionally, in order to manufacture a laminated piezoelectric element such as a laminated piezoelectric actuator or a laminated piezoelectric resonant element having electrodes inside, as shown in FIG. 8, a green sheet is first formed and then the green sheet is formed. Was punched into a plurality of sheets having a predetermined size and shape, and the punched green sheet was printed with internal electrodes such as Pt paste. Then, green sheets were stacked and pressure-bonded to obtain a fired product. After laminating this fired product to a predetermined thickness, an external electrode was formed and subjected to polarization treatment to manufacture a laminated piezoelectric element.

[0003]

However, in the conventional method for manufacturing a laminated piezoelectric element, since the ceramic sheet or the like is fired after printing the internal electrodes, the high melting point of Pt or the like is used as the electrode material of the internal electrodes. However, there is a problem that the manufacturing cost of the laminated piezoelectric element becomes high.

Further, the positional accuracy of the internal electrodes in the thickness direction is deteriorated due to the variation in the thickness of the green sheet. Therefore, there is also a problem that a high degree of control is required for manufacturing the green sheet.

Therefore, a main object of the present invention is to provide a method for manufacturing a laminated piezoelectric element which can reduce the manufacturing cost of the laminated piezoelectric element and does not require such strict green sheet management.

[0006]

The present invention comprises a step of firing a green sheet to form a ceramic sheet,
A step of polishing the ceramic sheet, a step of forming electrodes on both main surfaces of the ceramic sheet, a step of forming a glass layer on one main surface of the ceramic sheet, and a step of adhering a plurality of ceramic sheets by the glass layer. A method for manufacturing a laminated piezoelectric element, comprising: a step of forming a laminated body; and a step of polarizing a plurality of ceramic sheets.

The thickness of the glass layer is preferably 10 μm or less.

[0008]

Since the internal electrodes are printed after firing the ceramic sheet, there is no need to use expensive internal electrode materials such as Pt.

[0009]

According to the present invention, since the ceramic sheets are polished before being laminated, the strict management of the green sheets is not required. Moreover, since it is not necessary to use an expensive internal electrode material such as Pt, it is possible to suppress the manufacturing cost of the laminated piezoelectric element. Then, the laminated piezoelectric element can be easily manufactured by only slightly changing the conventional single plate ceramic manufacturing equipment.

The above-mentioned objects, other objects, features and advantages of the present invention will become more apparent from the detailed description of the embodiments below with reference to the drawings.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a flow chart showing a method of manufacturing a laminated piezoelectric element according to the present invention. First, a method of manufacturing the laminated piezoelectric actuator will be described.

First, a green sheet is formed, and the green sheet is punched into a plurality of sheets having a predetermined size and shape. Then, these green sheets are fired, and the obtained ceramic sheet is polished. Further, electrodes are formed on both main surfaces of the polished ceramic sheet. A paste-form glass is applied to one main surface of the ceramic sheet using an organic solvent or the like, and then the binder in the paste is degreased to form a glass layer.

The glass layer surface of the ceramic sheet and the glass layer non-formed surface of another ceramic sheet are overlapped to form 500
It heat-processed at -800 degreeC and adhered, and the laminated body was obtained. In addition,
The glass layer is not formed on one of the ceramic sheets positioned at both ends when the ceramic sheets are bonded. Then, a high voltage is applied to the ceramic sheet to perform a polarization treatment to impart piezoelectricity, and a laminated piezoelectric element is manufactured.

The electrodes formed on both main surfaces of the ceramic sheet are used when the ceramic sheet is polarized.
It is for providing electrical connection to both main surfaces of the ceramic sheet. However, when the thickness of the glass layer exceeds 10 μm, even if electrodes are formed on both main surfaces of the ceramic sheet in advance, the ceramic sheet is bonded by the glass layer and then the two main surfaces of the ceramic sheet are electrically connected. Becomes difficult. Therefore, the thickness of the glass layer is 10μ
It is preferably m or less.

FIG. 2 is a perspective view showing an example of the laminated piezoelectric actuator manufactured according to the present invention, and FIG. 3 is a view showing an essential part of FIG. The laminated piezoelectric actuator 10 is a laminated piezoelectric actuator that utilizes the vertical effect.

The laminated piezoelectric actuator 10 includes, for example, twelve ceramic sheets 12. Between the adjacent ceramic sheets 12, as shown in FIG. 3 in particular, the electrode 14a, the glass layer 16 and the electrode 14b are arranged in this order in the order of 1
It is formed one by one. The electrodes 14c are also formed on the outer main surfaces of the ceramic sheets 12 at both ends. Also,
As shown by arrows A and B in FIG. 2, these ceramic sheets 12 are polarized in the stacking order alternately in opposite directions and in the thickness direction thereof. Further, the electrodes 14a, 14b and 14c are alternately connected to the lead wire 18a and the lead wire 18b in the stacking order. The lead wire 18a is connected to, for example, the (+) pole of the power supply, and the lead wire 18b is connected to the (-) pole of the power supply.

Therefore, when a voltage is applied to the lead wires 18a and 18b, the laminated piezoelectric actuator 10 extends in the laminating direction as shown by arrows C and D in FIG.

In the conventional method, it was necessary to strictly control the green sheet, but according to this embodiment, since the polishing is performed before the ceramic sheets are laminated, it is not necessary to strictly control the green sheet. . Also,
According to this embodiment, since the internal electrodes are printed after firing the ceramic sheet, it is not necessary to use an expensive internal electrode material such as Pt, and the manufacturing cost of the laminated piezoelectric element can be suppressed.

FIG. 4 is a perspective view showing another example of the laminated piezoelectric actuator manufactured by the present invention.
FIG. 5 is an illustrative view of a main part of FIG. The laminated piezoelectric actuator 20 is a laminated piezoelectric actuator utilizing the lateral effect.

The laminated piezoelectric actuator 20 includes, for example, two ceramic sheets 22. Between the ceramic sheets 22, as shown in FIG. 5, electrodes 24a,
The glass layer 26 and the electrode 24b are formed one by one in this order. The electrodes 24c are also formed on the outer main surfaces of the ceramic sheets 22, respectively. The ceramic sheets 22 are polarized in the same thickness direction of the ceramic sheets 22, as shown by the arrow E in FIG. The electrodes 24a and 24b formed between the ceramic sheets 22 are connected to the lead wire 28a. The two outer electrodes 24c are connected to the lead wire 2
8b is connected. The lead wire 28a is connected to, for example, the (+) pole of the power supply, and the lead wire 28b is connected to the (-) pole of the power supply.

Therefore, when a voltage is applied to the lead wires 28a and 28b, the laminated piezoelectric actuator 20 warps and curves as shown by an arrow F in FIG.

The present invention can be applied not only to the laminated piezoelectric actuator utilizing the vertical effect as in this embodiment, but also to the laminated piezoelectric actuator utilizing the lateral effect.

Next, a method of manufacturing the harmonic energy trap type laminated resonator will be described.

Similar to the case of manufacturing a laminated piezoelectric actuator, a desired laminated body is obtained. No electrodes are formed on the outer main surface of this laminate. Then, an energy trapping type external electrode is formed on the outer main surface of this laminate and subjected to a polarization treatment to manufacture a harmonic energy trapping type laminated resonator.

FIG. 6 is a perspective schematic view showing a second-order harmonic energy confining type laminated resonator manufactured by the present invention, and FIG. 7 is a main part schematic view of FIG.

The second harmonic energy trap type laminated resonator 30 includes, for example, two ceramic sheets 32.
Between the ceramic sheets 32, the internal electrodes 34a, the glass layer 36, and the internal electrodes 34b are formed one by one in this order. External electrodes 38 are formed on the outer main surfaces of the ceramic sheets 32, respectively. The external electrode 38 includes a circular vibrating electrode 40 formed at the center of the main surface of the ceramic sheet 32, and the vibrating electrode 40 to the ceramic sheet 32.
And a T-shaped extraction electrode 42 extending to the end portion of the. Also,
Each of the ceramic sheets 32 is polarized in the thickness direction.

The present invention can be applied not only to the laminated piezoelectric actuator as in this embodiment, but also to the harmonic energy trap type laminated resonator.

[Brief description of drawings]

FIG. 1 is a flowchart showing a method for manufacturing a laminated piezoelectric element according to the present invention.

FIG. 2 is a perspective view showing an example of a laminated piezoelectric actuator manufactured according to the present invention.

FIG. 3 is an illustrative view of a main part of FIG.

FIG. 4 is a perspective view showing another example of the laminated piezoelectric actuator manufactured by the present invention.

5 is an illustrative view of a main part of FIG. 4. FIG.

FIG. 6 is a perspective view showing a second-order harmonic energy confinement type laminated resonator manufactured according to the present invention.

7 is an illustrative view of a main part of FIG.

FIG. 8 is a flowchart showing a conventional method for manufacturing a laminated piezoelectric element.

[Explanation of symbols]

10, 20 Multilayer piezoelectric actuator 12, 22, 32 Ceramic sheet 14a, 14b, 14c, 24a, 24b, 24c Electrode 16, 26, 36 Glass layer 30 Second harmonic energy trap type multilayer resonator 34a, 34b Internal electrode 38 External electrode

Claims (2)

[Claims] 1. A step of firing a green sheet to form a ceramic sheet, a step of polishing the ceramic sheet, a step of forming electrodes on both main surfaces of the ceramic sheet, and a main surface of the ceramic sheet. A method of manufacturing a laminated piezoelectric element, which comprises a step of forming a glass layer, a step of adhering a plurality of the ceramic sheets by the glass layer to form a laminated body, and a step of polarizing the plurality of ceramic sheets. . 2. The method for manufacturing a laminated piezoelectric element according to claim 1, wherein the glass layer has a thickness of 10 μm or less.