JP2001238474A - Method for manufacturing vibrator for pizeoelectric actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control amount of application of an adhesive having less fluctuation in the bonding operation of a piezoelectric element and an elastic body, obtain a high-quality adhesive layer, and stabilize the performance of a piezoelectric actuator. SOLUTION: A conductive adhesive transfer tool 32 is used as the piezoelectric element, or a means for applying an adhesive to the elastic body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for manufacturing a vibrator for a piezoelectric actuator constituted by bonding a piezoelectric element and an elastic body.

[0002]

2. Description of the Related Art Recently, in the field of microactuators, a piezoelectric actuator that obtains a driving force by utilizing a piezoelectric effect of a piezoelectric element has attracted attention.

[0003] This vibrator for a piezoelectric actuator is shown in FIG.
As shown in FIG. 6, a support 61, a support shaft 62 provided on the support 61, an elastic body 64 fixed to the support shaft 62, and a piezoelectric body bonded to one surface of the elastic body 64 via an adhesive layer 67. An element 65 and a lead wire 68 having one end connected to the piezoelectric element 65 and supplying an excitation signal are provided. The lead wire is joined to the insulating substrate 69, and the insulating substrate 69 is joined to the support 61. The connection between the lead wire 68 and the piezoelectric element 65 is
This is performed through a lead through hole 61b provided in the support base 61. Here, the piezoelectric element 65 has an electrode pattern 66 formed as a thin film, and adheres to the elastic body 64 to form the vibrating body 63. As an operation of the piezoelectric actuator, when an excitation signal is input to the vibrator configured as described above, the projection 64a provided on the elastic body 64 vibrates, and a disc-shaped movable element (not shown) uses the support shaft 62 as a rotation guide. Rotate.

Conventionally, a vibrator for a piezoelectric actuator, which is formed by bonding a piezoelectric element and an elastic body, applies an adhesive to the elastic body by a screen printing method or a dispenser, and superimposes the piezoelectric element on the elastic body. How to cure the agent. It was generally done. Japanese Patent Application Laid-Open No. H11-215864 discloses a method for transferring and applying an adhesive as an advantageous method for reducing the size of a vibrating body.

[0005]

However, in the work of bonding the piezoelectric element and the elastic body, it is necessary to accurately control the amount of the adhesive applied as the vibrator becomes smaller. In the method of applying an adhesive by using screen printing or a dispenser, it is difficult to control a very small amount, and fading is likely to occur. As a result, there is a problem that air bubbles are contained in the adhesive layer and stable adhesive quality cannot be ensured.
In particular, in the case of a vibrator for a piezoelectric actuator, if air bubbles are contained in the adhesive layer, the function of transmitting the excitation force of the piezoelectric element to the elastic body is impaired, so that the characteristics are significantly reduced.

[0006] On the other hand, the transfer coating method is advantageous in controlling a very small amount, as compared with the screen printing or the method of coating with a dispenser. However, the transfer coating method has a problem to reduce the variation in the transfer coating amount with respect to the change in the viscosity of the adhesive due to the charging of the adhesive transfer tool or a change in room temperature or the like.

SUMMARY OF THE INVENTION It is an object of the present invention to realize a piezoelectric actuator which stabilizes the performance of a piezoelectric actuator by realizing the control of the application amount of an adhesive with a small variation in a bonding operation of a piezoelectric element and an elastic body, obtaining a high quality adhesive layer. It is an object of the present invention to provide a method of manufacturing a vibrator for use.

[0008]

That is, the present invention provides a piezoelectric actuator for forming a vibrating body by bonding a piezoelectric element and an elastic body and generating a driving force based on bending vibration of the vibrating body. In the method of manufacturing a vibrator, a conductive adhesive transfer tool is used as a means for applying an adhesive to a piezoelectric element or an elastic body.

According to this, the transfer tool is no longer charged, no electrostatic attraction occurs between the insulating adhesive and the transfer tool, and the variation in the amount of application in which the transfer tool uses the adhesive more than necessary is reduced. I do.

Therefore, the use of the conductive adhesive transfer tool stabilizes the amount of application and improves the adhesive quality.

Further, the present invention is characterized in that the adhesive transfer tool is energized.

According to this, by applying a current to the adhesive transfer tool, the tool can be resistance-heated. By controlling the tool temperature, the viscosity of the adhesive can be kept constant.

Therefore, the viscosity of the adhesive, which fluctuates each time the room temperature changes, is kept constant, and the adhesive transfer amount can be precisely controlled. As a result, an adhesive layer free of bubbles is obtained.

According to another aspect of the present invention, an adhesive is applied by applying a voltage between the adhesive transfer tool and the elastic body or between the adhesive transfer tool and the piezoelectric element. Electrophoresis occurs between the tool and the elastic body, or between the adhesive transfer tool and the piezoelectric element. In the case of an insulating adhesive, the adhesive is ionized, which makes it easy to transfer the adhesive from the adhesive transfer tool to the elastic body or the piezoelectric element.

Therefore, the adhesive applied to the transfer tool generates an electrophoretic assist by a voltage applied between the transfer tool and the elastic body, or between the transfer tool and the piezoelectric element, and most of the adhesive is transferred from the transfer tool. You. As a result, the amount of adhesive applied can be precisely controlled, and an adhesive layer free of air bubbles can be obtained.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below in detail with reference to FIGS. Embodiment 1 First, a vibrating body manufactured by a method of manufacturing a vibrator for a piezoelectric actuator by applying the present invention will be described.

FIG. 1 is a diagram showing a planar structure of the vibrating body.

In FIG. 1, a vibrating body 3 includes a piezoelectric element 5
And an elastic body 4 bonded to the piezoelectric element 5 with an adhesive.

Here, the elastic body 4 has a disk shape corresponding to the piezoelectric element 5, and is made of an elastic material such as aluminum alloy, stainless steel, brass or the like. Further, column-shaped projections 4c are provided at every other six positions at positions corresponding to the boundaries of the divided portions of the piezoelectric element 5, and an inner peripheral positioning projection 4a and a center hole 4b are provided at the center.

The piezoelectric element 5 is formed into a disk shape using, for example, lead zirconate titanate, barium titanate, lead titanate, lithium niobate, lead niobate, lithium tantalate, or the like. Is provided with a center hole 5a. The center hole 5a of the piezoelectric element 5 is guided by an inner peripheral positioning projection 4a provided on the elastic body 4, and can be adhered concentrically.

The electrode pattern 6 formed on the piezoelectric element 5 can be formed by CVD or Pd using chromium, nickel, copper, gold or the like.
VD or other means is used to connect one roughly fan-shaped electrode to each divided part.
Films are formed at two places. In addition, the electrode pattern 6 is subjected to a total of six sets of polarization processing, with one set of adjacent divided parts divided into 12 equal parts. In the figure, (+) applies a positive electric field toward the contact surface with the elastic body 4 to perform polarization processing, and (−) applies a negative electric field toward the contact surface with the elastic body 4. This indicates that the polarization treatment was performed by applying the voltage.

FIG. 2 is a diagram showing a sectional structure of the vibrating body.

In FIG. 2, the vibrating body 3 includes a piezoelectric element 5
And the elastic body 4 adhered to the piezoelectric element 5.

Here, the elastic body 4 and the piezoelectric element 5 are adhered by an adhesive layer 27. When an excitation signal is input to the piezoelectric element 5, the elastic body 4 vibrates via the adhesive layer 27.
The function of the adhesive layer 27 is to transmit the vibration of the piezoelectric element 5 to the elastic body 4 with high efficiency. If the adhesive layer 27 contains air bubbles, the transmission efficiency of the vibration is significantly reduced.

FIG. 3 is an explanatory diagram relating to a method of manufacturing a vibrator for a piezoelectric actuator to which the conductive adhesive transfer tool of the present invention is applied. The ring transfer adhesive 37a after being applied to the elastic body 4 using the conductive adhesive transfer tool 32 is shown. Here, the adhesive transfer tool 32 was formed in a cylindrical shape using a metal such as brass, stainless steel, iron, and molybdenum.

As the evaluation of the adhesive transfer, the blurred state of the annular transfer adhesive 37a when the adhesive transfer tool width 32d was changed to 50 μm, 100 μm, and 200 μm was observed. This evaluation is performed in three stages, and the width of the ring transfer adhesive 37a is 3 with respect to the adhesive transfer tool width 32d.
0% or less, ○, 30-50% Δ, 50% ~
The fading was evaluated as x. In addition, as a comparative experiment, an adhesive transfer tool having the same shape was manufactured using silicon rubber and evaluated. Table 1 shows the results.

[0027]

[Table 1]

From Table 1, it can be seen that, in the case of the insulating adhesive transfer tool, a blur occurs when the tool width is 100 μm, whereas in the case where the conductive adhesive transfer tool 32 is used, the application is performed without a blur up to the tool width of 50 μm. It was possible to do. Embodiment 2 FIG. 4 is an explanatory diagram relating to a method of manufacturing a vibrator for a piezoelectric actuator in which a current is applied to a conductive adhesive transfer tool of the present invention and temperature control is applied. here,
Using molybdenum for the adhesive transfer tool 42, wiring 43a
And a wiring 43b was applied with a direct current. In addition, the adhesive transfer tool 42 generates heat when energized, and the voltage was controlled such that the temperature became 80 ° C. The adhesive transfer tool width 42d was set to 5
The temperature was fixed at 0 μm, and the room temperature was set at 20 ° C. and 30 ° C., and the blurring state of the ring transfer adhesive 47a was evaluated in three stages as in the first embodiment. Table 2 shows the results.

[0029]

[Table 2]

As shown in Table 2, when the adhesive transfer tool is energized, the annular transfer adhesive 21 does not fade at room temperature of 20 ° C. and 30 ° C., respectively.

FIG. 5 is an explanatory view relating to a method for manufacturing a vibrator for a piezoelectric actuator for applying a voltage between the conductive adhesive transfer tool and the elastic body 4. Here, molybdenum was used as the material of the application tool 52, the wiring 53a was connected to the application tool, and the wiring 53b was connected to an elastic body holding jig 58 for holding the elastic body 4. Similarly, the width 52d of the adhesive transfer tool is fixed at 50 μm, the room temperature is set at 20 ° C.,
At 30 ° C., the blurred state of the ring transfer adhesive 57a was evaluated. Table 3 shows the results.

[0032]

[Table 3]

According to Table 3, when a voltage is applied between the adhesive transfer tool and the elastic body, the annular transfer adhesive 57a does not fade at room temperature of 20 ° C. and 30 ° C., respectively. In addition, even when the adhesive is applied to the piezoelectric element 5 (not shown), by applying a voltage between the electrode pattern 6 formed on the piezoelectric element 5 and the adhesive transfer tool, the blur of the ring transfer adhesive can be reduced. Does not occur.

As described above, according to the present embodiment, most of the adhesive was transferred from the adhesive transfer tool, the amount of the applied adhesive could be precisely controlled, and an adhesive layer free of air bubbles was obtained. .

[0035]

As described above, according to the present invention, the amount of the adhesive applied was precisely controlled, and an adhesive layer free of air bubbles was obtained. Therefore, in the bonding operation of the piezoelectric element and the elastic body, the application amount of the adhesive with little variation is realized, and a high-quality adhesive layer is obtained to stabilize the performance of the piezoelectric actuator.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a planar structure of a vibrating body.

FIG. 2 is an explanatory diagram showing a cross-sectional structure of a vibrating body.

FIG. 3 is an explanatory diagram relating to a method of manufacturing a vibrator for a piezoelectric actuator to which the conductive adhesive transfer tool of the present invention is applied.

FIG. 4 is a diagram showing a state in which the conductive adhesive transfer tool of the present invention is energized;
It is explanatory drawing regarding the manufacturing method of the vibrator for piezoelectric actuators to which temperature control is applied.

FIG. 5 is an explanatory diagram relating to a method of manufacturing a vibrator for a piezoelectric actuator for applying a voltage between a conductive adhesive transfer tool and an elastic body.

FIG. 6 is an explanatory diagram showing a cross-sectional structure of a piezoelectric actuator vibrator.

[Explanation of symbols]

 REFERENCE SIGNS LIST 3 vibrating body 4 elastic body 5 piezoelectric element 6 electrode pattern 27 adhesive layer 32 adhesive transfer tool 37a ring transfer adhesive 42 adhesive transfer tool 43a, 43b wiring 52 adhesive transfer tool 53a, 53b wiring 57a ring transfer adhesive 58 Elastic body holding jig

Claims (3)

[Claims] A vibration for a piezoelectric actuator which forms a vibrating body by bonding a piezoelectric element and an elastic body, and generates a driving force based on bending vibration of the vibrating body. A vibrator for a piezoelectric actuator, wherein a conductive adhesive transfer tool (32) is used as a means for applying an adhesive to the piezoelectric element (5) or the elastic body (4). Manufacturing method. 2. The method for manufacturing a vibrator for a piezoelectric actuator according to claim 1, wherein the adhesive transfer tool is energized. 3. Applying a voltage between the adhesive transfer tool (52) and the elastic body (3) or between the adhesive transfer tool (52) and the piezoelectric element (5) to apply the adhesive. The method for manufacturing a vibrator for a piezoelectric actuator according to claim 1.