JP2001332777A - Plate-shaped piezoelectric material, method of manufacturing the same, and device for judging direction of its polarization - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plate-shaped piezoelectric material which can judge the direction of the polarization even after treatment such as polishing, cleaning of the surface is performed after polarization treatment. SOLUTION: Polarization treatment (S2) is performed in the specified direction of board thickness based on the external form, after the external form of plate-shaped piezoelectric material is processed (for example, one angle of a rectangle is cut off) into the form without a right and left symmetric axis (S1). As a result, even if the worker performs the treatment such as the polishing, the cleaning, etc., of the surface of plate-shaped piezoelectric material after, for example, polarization treatment, the features of external form is not lost, and the worker can prevent an error such as making a mistake in the direction of polarization at processing after that, by recognizing the direction of polarization based on the external form.

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 plate-shaped piezoelectric material for clarifying the polarization direction of the plate-shaped piezoelectric material and preventing the occurrence of mistakes in a post-processing step of the plate-shaped piezoelectric material. The present invention relates to a plate-shaped piezoelectric material and a polarization direction discrimination device for the plate-shaped piezoelectric material.

[0002]

2. Description of the Related Art For example, in a print head of an ink jet printer, a drive electrode is formed by forming a groove in a plate-shaped piezoelectric material polarized in a thickness direction, and ink is ejected by utilizing the shear deformation of the plate-shaped piezoelectric material. One configured to do so is known. In such a print head, for example, if a plate-shaped piezoelectric material is used in which the polarization direction is wrong and a groove is formed on the opposite surface, the opposite operation is performed when the same drive voltage is applied, so that a normal ink operates. Discharge cannot be performed. For example, a groove 52 is formed in a plate-shaped piezoelectric material 51 having a polarization direction as indicated by an arrow on the left side of FIG. 6 to form a drive electrode, and by applying a predetermined drive voltage, a deformation as shown on the right side of FIG. If this occurs, if the grooving is performed by reversing the polarization direction by mistake as shown on the left side of FIG. 7, the application of the same drive voltage as in FIG. 6 will result in a completely opposite deformation as shown on the upper right of FIG. . In this case, for example, a countermeasure such as setting the driving voltage to the opposite potential (lower right in FIG. 7) is required.

In order to prevent such a situation, it is necessary to correctly determine the polarization direction of the piezoelectric material.
Since the polarization direction of the piezoelectric material is internal, in order to determine the polarization direction, for example, it is necessary to apply an electric field to the piezoelectric material and observe its mechanical displacement. However, in the case of a plate-shaped piezoelectric material, even if an electric field is applied in the thickness direction, the mechanical displacement is small, and it is difficult to determine the polarization direction based on the mechanical displacement. In addition, even if an electric field is applied in a direction perpendicular to the thickness direction, the required voltage increases due to the long distance to which the voltage is applied, and a sufficient electric field intensity cannot be obtained. Have difficulty. Therefore, for example, Japanese Patent Application Laid-Open No. 2-283108 proposes a method for marking a front surface and a back surface according to the polarization direction when manufacturing a plate-shaped piezoelectric material, as shown in FIG. I have.

[0004]

However, in the above-described method of marking the surface of the plate-shaped piezoelectric material to determine the direction of polarization, for example, polishing, cleaning, or the like of the surface is performed after the polarization process. In such a case, it is assumed that the marking is erased at that time, and it becomes impossible to determine the polarization direction thereafter. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to correctly determine the polarization direction even after a process such as polishing or cleaning of the surface is performed after the polarization process. It is an object of the present invention to provide a plate-shaped piezoelectric material capable of performing the same, a method of manufacturing the same, and a polarization direction discriminating device thereof.

[0005]

According to a first aspect of the present invention, there is provided a method of manufacturing a plate-like piezoelectric material including a polarization treatment in a plate thickness direction. An outer shape processing step of processing an outer shape having no corresponding left-right symmetric axis is provided as a method of manufacturing a plate-shaped piezoelectric material. As a result, even if the surface of the plate-shaped piezoelectric material is polished or cleaned after the polarization processing, the characteristics of the external shape are not lost. Therefore, the polarization direction is determined based on the external shape. Accordingly, it is possible to prevent a mistake that the polarization direction is mistaken during the subsequent processing.

Here, in the outer shape processing step, it is conceivable that a shape having no left-right symmetric axis is formed by performing notch processing around a shape having a left-right symmetric axis, such as a rectangle, a square, or a circle. Can be Further, it is possible to carry out the outer shape processing step after the polarization processing. In this case, however, the outer shape processing itself may be performed in a direction opposite to the polarization direction. It is desirable to perform the above-mentioned polarization processing.

A second aspect of the present invention is a plate-shaped piezoelectric material manufactured by the above manufacturing method and having an outer shape that does not have a left-right symmetric axis according to a polarization direction.

A third invention is a device for determining the polarization direction of a plate-shaped piezoelectric material, which determines the polarization direction of the plate-shaped piezoelectric material, wherein the polarization direction of the plate-shaped piezoelectric material is oriented in a predetermined direction. Positioning means for positioning the plate-shaped piezoelectric material at a predetermined position only in the case where the polarization direction is determined based on whether or not the plate-shaped piezoelectric material has been positioned at the predetermined position by the positioning means. This is configured as a device for determining the polarization direction of a plate-shaped piezoelectric material. This makes it possible to automatically determine whether or not the polarization direction is correct by automatically detecting whether or not the plate-shaped piezoelectric material is correctly positioned at a predetermined position.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments and examples of the present invention will be described below with reference to the accompanying drawings to facilitate understanding of the present invention. The following embodiments and examples are mere examples embodying the present invention, and do not limit the technical scope of the present invention.

(Embodiment relating to a method for manufacturing a plate-shaped piezoelectric material) A method for manufacturing a plate-shaped piezoelectric material according to this embodiment is as follows.
It is constituted by a schematic procedure as shown in FIG. The method of manufacturing a plate-shaped piezoelectric material according to the present embodiment is characterized in that the method includes a step (S1) of performing a process for discriminating the front and back of the plate-shaped piezoelectric material before performing the polarization process (S2) in the plate thickness direction. It is common to the conventional manufacturing method (FIG. 8), but differs from the above-described conventional manufacturing method in that the process is to mechanically process the outer shape of the plate-shaped piezoelectric material.

In the machining step S1 (corresponding to the outer shape processing step) in the method for manufacturing a plate-shaped piezoelectric material according to the present embodiment, for example, a notch is formed in a part of the outer shape of the plate-shaped piezoelectric material so that the left-right symmetric axis is formed. Process into a shape that does not have.
If the outer shape of the plate-like piezoelectric material is processed into a shape having no left-right symmetric axis, the outer shape determines the direction of the front and back surfaces.

Specifically, for example, if the outer shape of the plate-like piezoelectric material is rectangular (FIG. 2A), one corner thereof is cut out (FIG. 2B), so that the piezoelectric material has no left-right symmetric axis. It can be shaped. If the outer shape of the plate-like piezoelectric material is a square, one corner thereof is cut asymmetrically (FIG. 3).
By (b)), a shape having no left-right symmetric axis can be obtained. In the case of a square, unlike a rectangle, a diagonal line also has an axis of left-right symmetry. Therefore, if one corner is cut off symmetrically (FIG. 3A), a left-right symmetry axis still exists. Similarly, when the outer shape of the plate-shaped piezoelectric material is a circle, a portion on the circumference thereof is cut asymmetrically (FIG. 4A), so that a shape having no left-right symmetric axis can be obtained. In addition, for example, if the outer shape of the plate-shaped piezoelectric material is a square, a portion on the side may be cut asymmetrically as shown in FIGS. 4B and 4C. Of course, this is the same in the case of a rectangle. In addition, there are a myriad of notch forming patterns in which the outer shape of the plate-shaped piezoelectric material does not have a left-right symmetric axis, but it goes without saying that any forming pattern may be used.

In the machining step S1, the outer shape of the plate-shaped piezoelectric material is processed into a shape having no left-right symmetric axis, and polarization processing is performed in a predetermined thickness direction based on the outer shape (S1).
2) For example, the plate-shaped piezoelectric material is processed for a head (for example, a groove is formed to form a drive electrode) (S).
3). At that time, for example, even if the surface of the plate-like piezoelectric material is polished or cleaned after the polarization process (S2),
Since the features on the outer shape are not lost, if the polarization direction is recognized based on the outer shape, mistakes such as erroneous polarization direction during the processing (S3) and grooving on the opposite surface will be made beforehand. Can be prevented.

As described above, according to the method for manufacturing a plate-shaped piezoelectric material according to the present embodiment, the outer shape of the plate-shaped piezoelectric material is processed into a shape having no left-right symmetric axis, and then the shape is determined based on the outer shape. Since the polarization process is performed in the predetermined thickness direction, even if the surface of the plate-like piezoelectric material is polished or cleaned after the polarization process, the characteristics of the outer shape are not lost. By recognizing the polarization direction on the basis of this, it is possible to prevent a mistake that the polarization direction is mistaken during the subsequent processing.

Although the above-mentioned machining step (S1) can be performed after the polarization processing (S2), in this case, there is a possibility that the outer shape processing itself is performed in a direction opposite to the polarization direction. Therefore, it is more desirable to perform machining (outer shape processing) before the polarization processing as in the above example.

(Embodiment relating to polarization direction determining apparatus)
Conventionally, as a processing apparatus for performing processing such as grooving on a polarized plate-shaped piezoelectric material, for example, as shown in FIG. 9, three positioning pins 60a, 60b, and 60c are used to form the plate-shaped piezoelectric material W. There was one that performed positioning. However, in the case of using the plate-shaped piezoelectric material W1 in which a notch is formed in a part of the outer shape so as not to have a left-right symmetric axis as described above, such a processing apparatus that performs positioning by using three positioning pins as shown in FIG. As shown in the figure, the plate-shaped piezoelectric material W1 is set at a predetermined position regardless of whether it is upside down (that is, whether or not the polarization direction is oriented), with both sides of the plate-like piezoelectric material W1 distinguished by the presence or absence of hatching. Therefore, it is not possible to automatically determine whether the polarization direction of the plate-shaped piezoelectric material W1 is correct.

Therefore, for example, as shown in FIG.
In addition to the positioning pins 60a, 60b and 60c, a new positioning pin 60 is provided at a position where the plate-shaped piezoelectric material W1 comes into contact with the cutout portion when the polarization direction is correctly set.
If a processing device provided with d (an example of a positioning means) is used, when the plate-shaped piezoelectric material W1 is set so that the polarization direction is reversed, the plate-shaped piezoelectric material W1 is correctly positioned at a predetermined position. Therefore, it is possible to automatically determine whether or not the polarization direction is correct by automatically detecting whether or not the plate-shaped piezoelectric material W1 is correctly positioned at a predetermined position.

As means for automatically detecting whether or not the plate-shaped piezoelectric material W1 is correctly positioned at a predetermined position, the four positioning pins 60a, 60b, 60c,
It is conceivable that all the switches 60d are constituted by contact switches. As a result, the set plate-shaped piezoelectric material W1 is transferred to the four positioning pins 60a, 60b, 60c, and 60.
When all of d are contacted, it can be determined that the plate-shaped piezoelectric material W1 is correctly positioned at a predetermined position (that is, the polarization direction is correct). Four positioning pins 60 as described above
A processing device having a, 60b, 60c, and 60d is an example of a polarization direction determination device.

Incidentally, the four positioning pins 60 as described above are used.
Other than those having a, 60b, 60c, and 60d, the plate-like piezoelectric material is placed in a predetermined position only when the polarization direction is oriented in a predetermined direction based on the outer shape of the plate-like piezoelectric material having no left-right symmetric axis. With a polarization direction determination device configured to include a positioning means capable of positioning at a predetermined position, it is possible to easily and accurately determine the polarization direction of a plate-shaped piezoelectric material having an outer shape that does not have a left-right symmetric axis as described above. It is.

[0020]

As described above, according to the method for manufacturing a plate-shaped piezoelectric material according to the first invention and the plate-shaped piezoelectric material according to the second invention manufactured thereby, for example, after the polarization process, Even if the surface of the plate-shaped piezoelectric material is polished or cleaned, its external characteristics are not lost. By determining the polarization direction based on the external shape, the polarization direction can be changed during subsequent processing. The mistake of making a mistake can be prevented beforehand.

Here, in the above-mentioned outer shape processing step, it is conceivable to form a shape having no left-right symmetric axis by performing notch processing around a shape having a left-right symmetric axis, for example, a rectangle, square, circle or the like. Can be Further, it is possible to carry out the outer shape processing step after the polarization processing. In this case, however, the outer shape processing itself may be performed in a direction opposite to the polarization direction. It is desirable to perform the above-mentioned polarization processing.

Further, according to the polarization direction discriminating apparatus according to the third invention, whether or not the polarization direction is correct is automatically determined by automatically detecting whether or not the plate-shaped piezoelectric material is correctly positioned at a predetermined position. It is possible to make a determination.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a processing procedure according to a method for manufacturing a plate-shaped piezoelectric material according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a notch formation pattern when the outer shape of a plate-shaped piezoelectric material is rectangular.

FIG. 3 is a diagram showing an example of a notch formation pattern when the outer shape of a plate-like piezoelectric material is a square.

FIG. 4 is a diagram showing an example of another notch formation pattern.

FIG. 5 is a schematic diagram showing a schematic configuration near a positioning means of the processing apparatus (polarization direction discriminating apparatus) according to the embodiment of the present invention.

FIG. 6 is an explanatory view showing a deformed state when a drive voltage is applied to a plate-shaped piezoelectric material on which drive electrodes are formed by performing groove processing (when the polarization direction is normal).

FIG. 7 is an explanatory diagram showing a deformed state when a drive voltage is applied to a plate-shaped piezoelectric material on which a drive electrode is formed by performing groove processing (when the polarization directions are opposite).

FIG. 8 is a flowchart illustrating an example of a processing procedure according to a conventional method for manufacturing a plate-shaped piezoelectric material.

FIG. 9 is a schematic diagram showing a schematic configuration near a positioning means of a conventional processing apparatus.

FIG. 10 is an explanatory view showing a state in which the plate-shaped piezoelectric material according to the present invention is set in the positioning means of the conventional processing apparatus.

[Explanation of symbols]

 W, W1 ... Plate-shaped piezoelectric material 60a-60d ... Positioning pin S1 ... Machining process (corresponding to external machining process)

Claims (5)

[Claims] 1. A method of manufacturing a plate-shaped piezoelectric material including a polarization process in a plate thickness direction, comprising an outer shape processing step of processing the plate-shaped piezoelectric material into an outer shape having no symmetric axis in accordance with the polarization direction. A method for producing a plate-shaped piezoelectric material, comprising: 2. The method for manufacturing a plate-shaped piezoelectric material according to claim 1, wherein in the outer shape processing step, the shape having no left-right symmetry axis is formed by performing notch processing around the shape having the left-right symmetry axis. 3. The method for manufacturing a plate-like piezoelectric material according to claim 1, wherein the polarization treatment is performed after the outer shape processing step. 4. A plate-shaped piezoelectric material having an outer shape that does not have a left-right symmetric axis according to a polarization direction. 5. A polarization direction discrimination device for a plate-shaped piezoelectric material which discriminates a polarization direction of a plate-shaped piezoelectric material processed into an outer shape having no left-right symmetry axis according to the polarization direction. Positioning means for positioning the plate-shaped piezoelectric material at a predetermined position only when the plate-shaped piezoelectric material is oriented in a predetermined direction, and determining whether or not the plate-shaped piezoelectric material has been positioned at the predetermined position by the positioning means. An apparatus for determining the direction of polarization of a plate-shaped piezoelectric material, comprising determining the direction.