KR20010003847A - A micro actuator of inkjet printhead and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A micro actuator of an ink-jet print head and a method for manufacturing the same are provided to maximize utilization efficiency of electrodes in a piezo-electric substances, thereby improving driving characteristic of the actuator. CONSTITUTION: A method for manufacturing a micro actuator of an ink-jet print head includes the steps of forming chambers(11) downwardly opened in a vibration plate(10) at regular gaps, accumulating piezo-electric substances(20) in the top surface of the vibration plate at a predetermined thickness, applying a photo-register to the top of the piezo-electric substances at a regular thickness, exposing and developing the photo-register by using a mask and removing unnecessary part of the photo-register by using washing solution, patterning to form piezo-electric substances having sectional area larger in the lower part than the upper part on the upper part of the chambers by contacting etching material with the part removed photo-register, removing the photo-register remaining on the top of the piezo-electric substances by using washing solution, and evaporating the upper electrodes not to contact with the vibration plate with completely covering the upper surface and the side surface of the piezo-electric substances.

Description

A micro actuator of inkjet printhead and manufacturing method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microactuator of an inkjet printer head for increasing driving force by increasing the amount of deformation of a piezoelectric body, and a method of manufacturing the same. Particularly, the electrode utilization efficiency in a piezoelectric body is increased by depositing the piezoelectric body to be covered with the upper electrode as much as possible. And it relates to a micro actuator of the inkjet printhead and the manufacturing method thereof so that the deformation amount of the diaphragm can be enhanced.

In general, inkjet printheads are mainly used in a thermal / bubble jet type and a piezoelectric type.

In the dual thermal bubble jet method, the chamber is electrically heated to allow ink in the chamber to be injected through the nozzle by thermal expansion, and the piezoelectric method drives the diaphragm by deformation of the piezoelectric body, and the ink in the chamber is driven by the vibration force. To be sprayed through.

Ink sprayed in the above manner has a size of several tens of micrometers (about 40 micrometers), and a very large number of particles are simultaneously sprayed at the same time, and therefore, precise operability is required above all.

1 illustrates an embodiment of a piezoelectric method which is the most commonly used among the above-described injection methods, and the piezoelectric material used is PZT.

The inkjet printhead of the piezoelectric injection method has a structure in which a plurality of thin plates are laminated, and the laminated thin plates have a nozzle (1, nozzle), a reservoir (2), and a restrictor (3, restrictor) for discharging ink. The chamber 4 and the chamber 5 are formed, and ink is ejected by the action of driving the piezoelectric body 8 and the vibration plate 6 on the upper chamber 4.

In other words, when power is supplied to the electrodes 7 and 9 formed on the upper and lower portions of the piezoelectric element 8, the piezoelectric element 8 contracts and expands, and the diaphragm 6 deforms when the piezoelectric element 8 is deformed. The bending deformation causes the volume in the chamber 4 to change.

Accordingly, when the diaphragm 6 is deflected by the contraction action of the piezoelectric body 8 while power is supplied to the electrodes 7 and 9, the volume of the ink in the chamber 4 is reduced while the volume in the chamber 4 is reduced. It discharges through the nozzle 1 via the flow path 5.

When the power supply is cut off, the contracted piezoelectric body 8 expands to the original state and expands the volume in the chamber 4 again. At this time, suction force is generated by the volume expansion in the chamber 4, and the reservoir ( 2) and the restrictor 3 allow a certain amount of ink to be filled in the chamber 4.

In this way, printing is performed by a continuous operation of filling or discharging ink into the chamber 4 by driving the piezoelectric body 8 and the diaphragm 6. The diaphragm 6, which is formed thereon, the piezoelectric body 8 and the electrodes 7 and 9 on the upper side thereof are generally referred to as a micro actuator.

On the other hand, it is no exaggeration to say that the driving force of the micro actuator is determined by the amount of deformation of the piezoelectric material 8 which is eventually deformed by a constant power supply.

In addition, the deformation of the piezoelectric body 8 is determined by the amount of electricity between the lower electrode 7 and the upper electrode 9 formed at the upper and lower portions thereof. The micro actuators currently used are as shown in FIG. It is manufactured in a configuration.

That is, the lower electrode 7 is deposited on the upper surface of the diaphragm 6 in which the chamber 4 is formed to have a fine thickness by screen printing, electroforming, bonding, etc., and patterning is performed as necessary. The upper portion of 7) allows the piezoelectric body 8 to be deposited to a thickness thicker than that of the lower electrode 7.

At this time, the piezoelectric material 8 may be formed by depositing by screen printing and patterning as shown in FIG. 2, or may be formed by etching as shown in FIG. 3.

On the other hand, in the configuration of such a micro actuator, in particular, the method of patterning the piezoelectric body 8 by etching as shown in FIG. 3 has already been proposed by the present applicant, and the piezoelectric body 8 in this case has a shape in which the lower part has a wider cross-sectional area than the upper part. It was a feature.

However, when the piezoelectric material 8 is patterned by etching, the upper electrode 9 formed on the upper portion of the piezoelectric material 8 is generally formed to have a structure covering only the top surface of the piezoelectric material 8, as shown in FIG.

If the upper electrode 9 is formed only above the piezoelectric body 8, the utilization efficiency of the electrode area which comes into contact with the piezoelectric body 8 eventually decreases, and this configuration reduces the current conduction rate between the electrodes 7 and 9. This causes the deformation of the piezoelectric body 8 to be reduced.

In other words, the amount of deformation of the piezoelectric body 8 is determined by the current carrying ratio between the electrodes 7 and 9, but in the past, in particular, the upper surface of the piezoelectric body 8 in which the upper electrode 9 has the narrowest cross-sectional area simply by patterning. Since it is formed in a structure that is deposited on, there is a problem in that the driving efficiency decreases while the current conduction rate between the electrodes 7 and 9 becomes small.

The present invention is to compensate for the above problems, the present invention is to ensure that the upper electrode is widely deposited over the upper surface and side of the piezoelectric body to maximize the utilization efficiency of the electrode so that the driving characteristics of the micro actuator can be more easily improved There is a main purpose.

In addition, the present invention has another object to greatly improve the workability of forming the upper electrode by simply depositing the upper electrode on the piezoelectric by evaporation or sputtering.

1 is a cross-sectional view showing an inkjet printhead of a conventional piezoelectric injection method;

Figure 2 is a cross-sectional view showing an embodiment of a conventional micro actuator,

3 is a cross-sectional view showing another embodiment of the conventional micro actuator,

4 is a cross-sectional view showing the structure of one embodiment of a micro actuator according to the present invention;

5 is a cross-sectional view showing the structure of another embodiment of a micro actuator according to the present invention;

6 to 10 show a first embodiment of manufacturing the micro actuator of the present invention,

11 to 12 show a second embodiment of manufacturing the micro actuator of the present invention,

13 to 14 show a third embodiment of manufacturing the micro actuator of the present invention.

<Description of the code | symbol about the principal part of drawing>

10: diaphragm 11: chamber

20: piezoelectric 30: upper electrode

40: lower electrode 50: photo-register

In order to achieve the above object, the present invention covers the upper and side surfaces of the piezoelectric body while simultaneously covering the upper and side surfaces of the piezoelectric body so as to be short-circuited with the diaphragm or the lower electrode formed at the bottom of the piezoelectric body to maximize electrode utilization efficiency in the piezoelectric body. The most striking feature is that

Preferred embodiments according to this will be described in detail with reference to the accompanying drawings.

Figure 4 shows an embodiment of a micro actuator according to the present invention, the reference numeral 10 is a diaphragm, the diaphragm 10 is formed with a chamber 11 to open downward at regular intervals.

At this time, the diaphragm 10 is most preferably made of a conductive metal material so that the diaphragm 10 can be used as a common electrode without having a separate lower electrode.

The piezoelectric body 20 is formed on the diaphragm 10 at the upper surface of which the chamber 11 is formed. In this case, the piezoelectric body 20 is formed in such a manner that the lower portion thereof has a wider cross-sectional area than the upper portion.

An upper electrode 30 is deposited on the piezoelectric body 20 formed in the diaphragm 10 together with the chamber 11 at regular intervals so as to simultaneously cover the upper and side surfaces except for the bottom contacting the diaphragm 10.

In this case, the upper electrode 30 deposited on the piezoelectric body 20 has a configuration in which a lower end of a portion covering the side surface of the piezoelectric body 20 is short-circuited with the diaphragm 10.

5 shows another embodiment of the micro actuator according to the present invention, in which the diaphragm 10 is configured such that the chamber 11 is formed to be opened downward at regular intervals on the plate surface in the same manner as in the above-described embodiment.

The diaphragm 10 at this time is made of a non-conductive material.

The lower electrode 40 is stacked on the upper surface of the diaphragm 10 so that the lower electrode 40 can be used as a common electrode, and the piezoelectric body 20 is formed in the lower electrode 40 at a position directly above the chamber 11.

At this time, the piezoelectric body 20 is also formed so that the lower portion is formed in a wider cross-sectional area than the upper portion by etching as in the foregoing embodiment, and the upper electrode 30 is deposited on the upper and side surfaces of the piezoelectric body 20. do.

The upper electrode 30 deposited on the piezoelectric body 20 is such that the lower end of the portion covering the side surface of the piezoelectric body 20 is necessarily shorted with the diaphragm 10.

The micro actuator as described above can be manufactured by the following process.

6 to 10 illustrate a first embodiment of manufacturing the micro actuator according to the present invention, and first, the chamber 11 is formed at regular intervals so as to open downward to the diaphragm 10, and the diaphragm 10 6, the piezoelectric body 20 is laminated with a predetermined thickness as shown in FIG.

The photoresist 60 is applied to the upper surface of the piezoelectric body 20 at a constant thickness as shown in FIG. 7, exposed and developed using a mask, and then, as shown in FIG. 8, using a cleaning solution. Eliminate unnecessary parts.

If the piezoelectric body 20 is etched by contacting the etching material to the portion where the photoresist 60 is removed, the piezoelectric body 20 having a lower cross-sectional area larger than the upper portion of the chamber 11 remains as shown in FIG. 9. do.

In this state, the photoresist 60 remaining on the top of the piezoelectric body 20 is completely removed by using a cleaning liquid, and the upper electrode 30 is deposited from the top of the piezoelectric body 20 as shown in FIG. 10.

In this case, the deposition method of the upper electrode 30 is to be deposited by evaporation or sputtering, and the deposited upper electrode 30 completely covers the upper and side surfaces of the piezoelectric body 20, but the diaphragm and Should be short-circuited without contact.

Unlike the portion deposited on the piezoelectric body 20 when the upper electrode 30 is deposited, a part of the electrode is also formed in the diaphragm 10 between the piezoelectric bodies 20, which may be left as it is or may be removed.

By such a process, a micro actuator as shown in FIG. 4 is manufactured.

11 to 12 illustrate a second embodiment of manufacturing the micro actuator according to the present invention, the first embodiment of the present invention is provided with the diaphragm 10 so that the chamber 11 is formed at a predetermined interval. Same as in the example.

The lower electrode 40 is stacked on the diaphragm 10 provided as shown in FIG. 11, and the piezoelectric body 20 is stacked on the upper surface of the lower electrode 40 at a predetermined thickness as shown in FIG. 12.

As the upper surface of the piezoelectric body 20, the photoresist 60 is applied to a predetermined thickness as in the first embodiment of FIGS. 7 to 10, and the cleaning solution is used after performing exposure and development using a mask. Thus, unnecessary portions of the photoresist are removed, and the piezoelectric material 20 is etched by contacting an etching material to a portion where the photoresist 60 is removed.

Subsequently, the photoresist 60 remaining on the upper portion of the piezoelectric body 20 is completely removed using a cleaning liquid, and then the upper electrode 30 is deposited from the upper portion of the piezoelectric body 20.

At this time, the piezoelectric body 20 is formed such that the lower portion has a larger cross-sectional area than the upper portion, and the upper electrode 30 is deposited by evaporation or sputtering, but the upper electrode 30 is deposited. The upper and side surfaces of the piezoelectric body 20 are completely covered while being in a shorted state not in contact with the diaphragm.

In particular, a portion of the electrode is also deposited on the diaphragm 10 between the piezoelectric body 20, unlike a portion deposited on the piezoelectric body 20 when the upper electrode 30 is deposited, but it may be left as it is and may be removed. have.

By such a process, the micro actuator which has a structure as shown in FIG. 5 is manufactured.

Meanwhile, FIGS. 13 to 3 show a third embodiment for manufacturing the micro actuator of the present invention. In the present embodiment, the chamber 11 is formed at regular intervals so that the diaphragm 10 is provided. The same as in the first embodiment and the second embodiment.

The lower electrode 40 is stacked on the diaphragm 10, and the piezoelectric body 20 is patterned and deposited on the lower electrode 40 by screen printing as shown in FIG. 13.

At this time, the piezoelectric body 20 has a shape in which the upper and lower cross-sectional areas are substantially the same as those of the foregoing embodiment, so that the side surfaces are almost vertical.

When the upper electrode 30 is deposited on the piezoelectric body 20 formed as described above in the first and second embodiments by evaporation or sputtering, a micro actuator as shown in FIG. 14 is formed.

By forming the micro actuator according to the above-described configuration and manufacturing method, the electrode utilization area in the piezoelectric body 20 can be expanded to maximize the utilization efficiency of the electrode.

In addition, when the upper electrode 30 is deposited, the ends of the upper electrode 30 are finely spaced apart from the diaphragm 10 or the lower electrode 40 so that the contact is disconnected from each other, thereby maintaining a stable energized state. .

In particular, the formation of the upper electrode 30 is finally performed in the manufacturing step of the micro actuator to enable safe and accurate deposition without affecting other processes at all.

Therefore, the upper electrode deposited on the piezoelectric body can be more easily formed by the configuration and manufacturing method of the micro actuator as described above, and the upper electrode can be widely distributed on the piezoelectric body to maximize the utilization efficiency of the electrode.

In addition, the use efficiency of the electrode increases the deformation of the piezoelectric body and the diaphragm, thereby increasing the driving force in the micro actuator, thereby providing an inkjet printhead having more powerful injection force.

Claims (13)

A diaphragm for allowing chambers to be formed at regular intervals; A piezoelectric body laminated on the upper surface of the diaphragm where the chamber is formed such that a lower portion thereof has a larger cross-sectional area than the upper portion thereof; And An upper electrode deposited to cover the upper and side surfaces of the piezoelectric body and to be disconnected from the diaphragm; Micro actuator of inkjet printhead in this combined configuration. The diaphragm of claim 1, wherein the diaphragm Micro actuator of inkjet printhead made of conductive metal. A diaphragm for allowing chambers to be formed at regular intervals; A lower electrode stacked on an upper surface of the diaphragm; A piezoelectric body laminated on the upper surface of the lower electrode where the chamber is formed so that a lower portion thereof has a wider cross-sectional area than an upper portion thereof; And An upper electrode deposited to cover the upper and side surfaces of the piezoelectric body and to be disconnected from the diaphragm; Micro actuator of inkjet printhead in this combined configuration. The diaphragm of claim 2, wherein the diaphragm Micro-actuator for non-conductive inkjet printheads. Allowing the chamber to be opened downward to the diaphragm at regular intervals; Stacking a piezoelectric body with a predetermined thickness on an upper surface of the diaphragm; Coating a photoresist with a constant thickness on an upper surface of the piezoelectric body; Exposing and developing the photoresist using a mask, and removing unnecessary portions of the photoresist using a cleaning liquid; Patterning the etching material to be in contact with the portion where the photoresist is removed to form a piezoelectric body having a lower cross-sectional area than an upper portion directly above the chamber; Removing the photoresist remaining on the upper portion of the piezoelectric body using a washing liquid, and Depositing an upper electrode so as not to be in contact with the diaphragm while completely covering an upper surface and a side surface of the piezoelectric body from an upper portion of the piezoelectric body, A microactuator manufacturing method of an inkjet printhead performed as a. The method of claim 5, wherein the upper electrode A method for manufacturing a micro actuator of an ink jet print head which is vacuum deposited by evaporation. The method of claim 5, wherein the upper electrode A microactuator manufacturing method of an inkjet printhead deposited by sputtering. Allowing the chamber to be opened downward to the diaphragm at regular intervals; Stacking a lower electrode on an upper surface of the diaphragm; Stacking a piezoelectric body on the lower electrode at a predetermined thickness; Coating a photoresist with a constant thickness on an upper surface of the piezoelectric body; Exposing and developing the photoresist using a mask, and removing unnecessary portions of the photoresist using a cleaning liquid; Patterning the etching material to be in contact with the portion where the photoresist is removed to form a piezoelectric body having a lower cross-sectional area than an upper portion directly above the chamber; Removing the photoresist remaining on the upper portion of the piezoelectric body using a washing liquid, and Depositing an upper electrode so as not to contact the lower electrode while completely covering an upper surface and a side surface of the piezoelectric body from an upper portion of the piezoelectric body, A microactuator manufacturing method of an inkjet printhead performed as a. The method of claim 8, wherein the upper electrode A method for manufacturing a micro actuator of an ink jet print head which is vacuum deposited by evaporation. The method of claim 8, wherein the upper electrode A microactuator manufacturing method of an inkjet printhead deposited by sputtering. Allowing the chamber to be opened downward to the diaphragm at regular intervals; Stacking a lower electrode on an upper surface of the diaphragm; Patterning and depositing a piezoelectric body on the lower electrode by screen printing; Depositing an upper electrode so as not to contact the lower electrode while completely covering an upper surface and a side surface of the piezoelectric body from an upper portion of the piezoelectric body, A microactuator manufacturing method of an inkjet printhead performed as a. The method of claim 11, wherein the upper electrode A method for manufacturing a micro actuator of an ink jet print head which is vacuum deposited by evaporation. The method of claim 11, wherein the upper electrode A microactuator manufacturing method of an inkjet printhead deposited by sputtering.