KR20070120745A - Printer head unit of apparatus for manufacturing display substrate - Google Patents

Abstract

A print head unit of an apparatus for manufacturing a display panel is provided to minimize the generation of bubbles by forming an ink supply path in a triangular shape and cutting edges of the ink supply path. A print head unit of an apparatus for manufacturing a display panel comprises a common path for providing ink to a pressure chamber, a piezoelectric device, a nozzle and an ink supply part(100). The nozzle sprays the ink discharged from the pressure chamber to the outside. The ink supply part includes an ink supply tube for feeding ink and an ink supply path(120) for moving the ink into an ink discharging hole(130) such that the ink is discharged into the common path. The ink supply path includes a bottom surface(126) having the ink discharging hole and a side wall having an edge which is connected with the ink supply tube and has a triangular shape.

Description

Print head unit of display board manufacturing apparatus {PRINTER HEAD UNIT OF APPARATUS FOR MANUFACTURING DISPLAY SUBSTRATE}

1 is a view showing a print head unit according to an embodiment of the present invention.

FIG. 2 is a front view of the ink supply unit shown in FIG. 1.

FIG. 3 is a side view of the ink supply unit shown in FIG. 1.

4 to 7 are conceptual views illustrating an initial supply process of ink to an ink supply unit according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

500: print head unit 100: ink supply unit

110: ink supply tube 120: ink supply flow path

130: ink outlet 140: solvent supply pipe

150: air piping 160: three-way control valve

240: piezoelectric element 251: insertion hole

252: common euro

The present invention relates to a print head unit of a display substrate manufacturing apparatus, and more particularly, to a print head unit for improving the quality of a color filter.

In general, an inkjet print head generates a bubble in ink by using a heat source according to an ink ejection method, and a permanent copper method in which ink is ejected by the expansion force of the bubble, and a deformation of the piezoelectric element using a piezoelectric element. Therefore, there is a piezoelectric method for discharging ink by the pressure applied to the ink. The piezoelectric inkjet print head includes piezoelectric elements, pressure chambers, a common flow path, a restrictor, nozzles, and an ink supply unit.

Meanwhile, in manufacturing a color filter using inkjet printing, color filters are formed by spraying ink on a pixel portion formed in a black matrix pattern. In order for the color filters to be uniform and have excellent color characteristics, the color filters between pixels must be uniformly formed.

For this purpose, the same amount of ink must be injected without clogging the nozzles of the print head, but in reality, the amount of ink to be sprayed is different for each nozzle, and the nozzles are clogged, causing problems in forming the color filters uniformly. have.

Therefore, the technical problem of the present invention has been conceived in this regard, the object of the present invention is to minimize the amount of bubbles generated inside the ink supply flow path, and to discharge the uniform amount of ink to improve the quality of the color filter To provide a unit.

The print head unit according to the embodiment for realizing the object of the present invention is a common flow path for supplying ink to the pressure chamber, piezoelectric elements for providing pressure to the pressure chamber, the ink discharged from the pressure chamber An ink supply unit having an injection nozzle for jetting to the ink and an ink supply tube into which ink is injected, and an ink supply flow path for discharging the injected ink to an ink discharge port and discharging the ink to the common flow path, wherein the ink supply flow path is the ink supply path. And a bottom surface facing the tube, the bottom surface of which the ink discharge port is formed, and triangular sidewalls having rounded edges connecting the bottom surface and the ink supply tube.

The print head unit may prevent bubbles from being generated inside the ink supply flow path, and improve reliability of the print head by uniformly supplying the ink to the common flow path. Furthermore, the display quality may be improved by improving the quality and color reproducibility of the color filters formed by jetting using the print head unit.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention.

1 is a view showing a print head unit according to an embodiment of the present invention.

Referring to FIG. 1, the print head unit 500 includes a plurality of substrates, piezoelectric elements 240, and an ink supply unit 100. The plurality of substrates include a first substrate 210, a second substrate 220, and a third substrate 230 sequentially stacked, and include first, second, and third substrates 210, 220, and 230. The ink passage is formed in the field. Piezoelectric elements 240 generating a driving force for ejecting ink are formed on the third substrate 230.

The plurality of substrates are made of, for example, a single crystal silicon wafer. The plurality of substrates precisely form the ink flow path in minute sizes on each of the first, second, and third substrates 210, 220, and 230 by using photolithography and etching techniques. The ink flow path includes a common flow path 252, a restrictor 253, a pressure chamber 254, and an injection nozzle 256.

The common flow path 252 is filled with ink supplied from the outside, and supplies the ink to the plurality of pressure chambers 254. The common flow path 252 is formed long in one direction on the second substrate 220 and is formed to a predetermined depth from an upper surface of the second substrate 220.

An insertion hole 251 is formed in the third substrate 230 corresponding to the common flow path 252 to vertically penetrate the third substrate 230 in a shape similar to that of the common flow path 252. A portion of the ink supply unit 100 is inserted into the insertion hole 251 to supply external ink to the common flow path 252.

The restrictor 253 is a separate flow path for supplying the ink from the common flow path 252 to each pressure chamber 254. The restrictor 253 may be formed to have a predetermined depth from an upper surface of the second substrate 220, or may be formed by vertically penetrating the second substrate 220.

The pressure chamber 254 generates a pressure change for ejecting the ink to the outside through the spray nozzle 256. When the external ink is filled in the common flow path 252, the ink is filled in the pressure chamber 254 through the list 253.

The pressure chambers 254 are formed at a predetermined depth on the lower surface of the third substrate 230, and are arranged in a line perpendicular to the common flow path 252 on both sides of the common flow path 252, respectively. Alternatively, only one side of the common flow path 252 may be arranged in a line.

A spray nozzle 256 ejects the ink filled in the pressure chamber 254 to the outside. The spray nozzle 256 is formed to vertically penetrate the first substrate 210. Between the pressure chamber 254 and the spray nozzle 256, a damper 255 for concentrating energy generated in the pressure chamber 254 by the piezoelectric element 240 toward the spray nozzle and buffering a sudden pressure change may be further formed. Can be.

The piezoelectric element 240 is formed on the third substrate 230 corresponding to the pressure chamber 254 to provide a driving force for ejecting the ink to the pressure chamber 254. The piezoelectric element 240 includes a lower electrode 241 that is a common electrode, a piezoelectric film 242 that is deformed by application of a voltage, and an upper electrode 243 that is a driving electrode.

The piezoelectric element 240 has a structure in which the lower electrode 241, the piezoelectric layer 242, and the upper electrode 243 are sequentially stacked on the third substrate 230. In detail, the lower electrode 241 is formed on the entire surface of the third substrate 230 and is formed of one or two or more conductive metal materials.

The piezoelectric film 242 is formed on the lower electrode 241 and is disposed at a position corresponding to the pressure chamber 254. The piezoelectric film 242 is deformed by the application of a voltage to change the volume of the pressure chamber 254. The piezoelectric film 242 is formed of a piezoelectric material, for example, a lead zirconate titanate (PZT) ceramic material. The upper electrode 243 serves as a driving electrode for applying a voltage to the piezoelectric film 242 and is formed on the piezoelectric film 242.

The ink supply unit 100 inserts the lower end of the ink supply unit 100 into the insertion hole 251 to supply external ink to the common flow path 252. The shape and size of the lower end of the ink supply unit 100 is preferably formed to be the same as the shape and size of the insertion hole 251.

FIG. 2 is a front view of the ink supply unit shown in FIG. 1.

FIG. 3 is a side view of the ink supply unit shown in FIG. 1.

1, 2, and 3, the ink supply unit 100 will be described in detail. The ink supply unit 100 includes an ink supply tube 110 and an ink supply tube 110 to which the solvent supply pipe 140 is connected. Connected ink supply flow path 120 and ink discharge port 130.

The ink supply tube 110 includes a first side end 112 into which ink INK is injected from the outside, and a second side end 114 formed in a direction opposite to the first side end 112. The ink supply tube 110 has a pipe shape connecting the first and second side ends 112 and 114.

The external ink INK injected into the first side end 112 moves to the ink supply flow path 120 through the second side end 114 of the ink supply tube 110. The second side end 114 of the ink supply tube 110 is connected with the ink supply flow path 120.

The solvent supply pipe 140 is connected between the first side end 112 and the second side end 114 of the ink supply tube 110. The solvent supply pipe 140 extends perpendicularly to the ink supply tube 110. The solvent is supplied to the ink supply passage 120 through the solvent supply pipe 140 to wash the ink supply passage 120. By supplying a solvent (SOLVENT) to the ink supply flow path 120 through the solvent supply pipe 140 may serve as a guide of the ink during the initial supply of the ink. The solvent supply pipe 140 further includes a solvent control valve 142 that can control whether or not the solvent SOLVENT is supplied from the outside.

The air pipe 150 is connected to extend perpendicular to the solvent supply pipe 140. The air pipe 150 preferably extends in parallel with the ink supply tube 110. When the inks are initially supplied, the air pipe 150 serves to discharge air bubbles generated by the inks by buoyancy. The air pipe 150 further includes an air control valve 160 to control whether the air passing through the air pipe 150 is moved.

The ink supply unit 100 includes a three-way control valve 160 formed at a portion where the ink supply tube 110 and the solvent supply pipe 140 are connected to each other. The three-way regulating valve 160 includes a first valve 162, a second valve 164, and a third valve 166 and regulates the first, second and third valves 162, 164, 166. Thereby opening or blocking the movement path of the ink, the bubble and the solvent.

The first valve 162 is formed between the first and second side ends 112 and 114 of the ink supply tube 110 and moves from the first side end 112 to the second side end 114. The movement of the ink can be adjusted. The second valve 164 is disposed to face the first valve 162. The third valve 166 is located in the solvent supply pipe 140 corresponding to the portion where the ink supply tube 110 and the solvent supply pipe 140 are connected, and the third valve 166 is connected to the solvent control valve 142. Is disposed towards.

The movement path controlled by the three-way control valve 160 is a first movement path, which is a path through which the ink moves in the ink supply tube 110, through the ink supply tube 110 to the air pipe 150 through the bubble. And a third moving path through which the solvent moves to the ink supply tube 110 through the moving second moving path and the solvent supply pipe 140.

Specifically, the first movement path of the ink is in the direction from the first side end 112 to the second side end 114 and uses the first and second valves 162 and 164 to direct the first movement path. By adjusting the ink can be controlled whether the ink flows into the ink supply passage (120).

The second movement path is a path through which the bubble moves from the second side end 114 to the air pipe 150 through the connection portion of the ink supply tube 110 and the solvent supply pipe 140, and the air control valve 152. ) And the solvent control valve 142 may be closed and the first valve 162 may be closed to control whether the air bubbles are discharged.

The third movement path is a path through which the solvent moves from the solvent supply pipe 140 to the ink supply flow path 120 through the ink supply pipe 110, and the first valve 162 and the air regulating valve 152. By closing, the solvent may control whether the solvent flows into the ink supply passage 120.

The ink supply flow path 120 has the second side end 112 of the ink supply tube 110 as an upper end to a lower end which is the bottom surface 126 of the ink supply flow path 120 facing the second side end 112. Is extended. The external ink moves from the upper end to the lower end, that is, from the ink supply tube 110 along the ink supply passage 120 to the bottom surface 126.

The ink supply passage 120 includes a rectangular bottom surface 126 and a plurality of sidewalls connected to the bottom surface 126. The plurality of sidewalls may include a first sidewall 122, a second sidewall facing the first sidewall 122, a third sidewall 122 and a third sidewall 124 connecting the second sidewall; And a fourth sidewall facing the three sidewalls 124.

The first to fourth sidewalls have a triangular shape with rounded edges. The first sidewall 122 and the second sidewall are joint, and the third sidewall 124 and the fourth sidewall are joint.

The height x of the ink supply passage 120 is preferably formed to be 2 mm or less. The height x of the ink supply passage 120 is defined as the vertical distance between the second side end 114 of the ink supply tube 110 and the bottom surface 126. As the height x of the ink supply passage 120 is lower, generation of bubbles in the ink supply passage 120 may be minimized.

As the sidewall of the ink supply passage 120 of the present invention is formed in a triangular shape, and the triangular edge is rounded, the ink flowing into the ink supply unit 100 from the ink supply tube 110 is bottomed. Instead of reaching 126 directly, it can move along the ink supply flow path 120 to the bottom surface 126.

Since the ink moves to the bottom surface 126 along the ink supply passage 120, bubbles may be prevented from occurring in the ink supply unit 100. As the height (x) of the ink supply passage 120 is formed to be 2 mm or less, the effect of preventing bubbles from occurring in the ink supply unit 100 is further improved.

On the other hand, the distance from the ink supply tube 100 to each ink discharge port 130 is equally formed. By forming the same distance, the amount of ink discharged from each ink outlet 130 is equal. The first sidewall 122 of the ink supply passage 120 is formed in an isosceles triangular shape with rounded vertices.

An ink outlet 130 for supplying the ink to the common channel 252 is formed on the bottom surface 126, and the ink outlet 130 is formed at both ends of the bottom surface 126, respectively. In detail, the ink outlet 130 is formed at both end portions of the bottom surface 126 connected to the third side wall 126 and the fourth side wall.

Referring to FIG. 3, the shape of the side surface of the ink supply passage 120 is also formed in a triangular shape. The width of the upper end of the side is narrower than the width of the lower end of the side, and the width gradually increases from the upper end of the side to the lower end of the side. Since the side surface is formed in a triangular shape, the ink can smoothly move from the upper end of the ink supply flow path 120 to the bottom surface 126 along the ink supply flow path 120.

4 to 7 are conceptual views illustrating an initial supply process of ink to an ink supply unit according to an embodiment of the present invention.

Referring to FIG. 4, before supplying ink, the air regulating valve 152 and the first valve 162 of the air pipe 150 are closed. Closing the first valve 162 blocks the first travel path of the ink. The solvent control valve 142, the second valve 164 and the third valve 166 of the three-way control valve 160 are opened to open the third movement path of the solvent.

Subsequently, a solvent (SOLVENT) is injected into the solvent supply pipe 140 so that the solvent moves from the solvent supply pipe 140 into the ink supply flow path 120 along the third movement path, so that the solvent of the ink supply flow path 1320 is removed. The solvent (SOLVENT) is filled inside. The solvent SOLVENT is, for example, a solvent containing a small amount of surfactant.

Referring to FIG. 5, the solvent control valve 142, the air control valve 152, and the third valve 166 are closed. Closing the third valve 166 blocks the third travel path of the solvent. The first valve 162 and the second valve 164 are opened to open the first movement path of the ink, and the external ink INK introduced from the ink supply tube 110 is moved to the ink supply flow path 120. .

The external ink INK is introduced into the ink supply passage 120 which is already filled with the solvent SOLVENT, and the external ink INK and the solvent SOLVENT are not mixed. The external ink INK is filled on the solvent SOLVENT of the ink supply passage 120 in which the solvent SOLVENT is already filled.

The solvent SOLVENT is introduced into the external ink INK and is discharged to the outside of the ink supply unit 100 through the ink outlet 130. The ink INK is discharged to the outside of the ink supply unit 100 through the ink discharge port 130 along the path of the solvent SOLVENT discharged to the outside of the ink supply unit 100. The solvent SOLVENT serves as a guide of the ink INK when the ink is initially supplied.

Referring to FIG. 6, the ink moves to the ink supply flow path 120 through the ink supply tube 110, and the ink flows from the bottom surface 126 to the ink supply part 100 along the ink supply flow path 120. Is filled. The first valve 162 and the second valve 164 are opened to fill the ink supply flow path 120 along the first movement path of the ink. At the same time, the third valve 166 and the air control valve 152 are opened to form the second moving path of the bubble.

Bubbles generated when the ink is initially supplied are floated to the surface of the ink by buoyancy. Bubbles that rise to the surface of the ink are discharged to the outside of the ink supply unit 100 along the second movement path. Bubbles rising to the surface of the ink can be moved smoothly on the inclined wall surface by the ink supply flow path 120 is formed in the triangular shape.

In the piezoelectric printhead of the conventional general structure, the generation of bubbles plays a critical role in the normal ejection of ink. The bubbles may occur while passing through various seams while the ink is supplied from the ink supply portion to the print head, and may occur naturally when the ink undergoes various pressure differences when various kinds of gases are dissolved in the ink.

As such, when bubbles are generated in the ink, normal ink injection is prevented due to a change in volume in the pressure chamber, and further, an ink flow path such as a restrictor is blocked to hinder the flow of the ink. The generation of bubbles causes severe performance degradation of the entire print head unit and difference in ink ejection performance at a plurality of ejection nozzles. Since the bubbles are very small in units of tens of micrometers, there is a problem in that surface tension is large and difficult to remove.

Although there is a method of filtering by installing a filter inside the ink supply unit to remove the bubbles, the method of filtering the bubbles by the filter may filter the bubbles to a certain level, but bubbles are accumulated on one side of the filter. As a result, clogging of the spray nozzle of the print head cannot be fundamentally solved. In addition, there was a need to periodically replace the filter.

However, the ink supply unit 100 of the present invention changes the shape of the ink supply flow path 120, and further includes a solvent supply pipe 140 and an air pipe 150 to minimize the generation of the bubbles and to eliminate the bubbles already generated. Since it can be removed, the reliability of the ink supply unit 100 can be improved. As a result, the ink supplied from the ink supply unit 100 may be uniformly moved to the injection nozzle 256 to improve the reliability of the print head 500.

Referring to FIG. 7, the third valve 166, the solvent control valve 142, and the air control valve 152 of the three-way control valve 160 are closed, and the first valve 162 and the second valve 164 are closed. Open the bay Accordingly, the ink discharge port 130 uniformly discharges the ink into the common flow path 251, and the spray nozzle 256 uniformly ejects the ink.

According to such a print head, the ink supply flow path of the ink supply part is formed in a triangular shape, and the edges of the triangular shape are rounded to smooth the movement of the ink, thereby minimizing bubbles in the ink supply part.

The ink supply tube is located at the center of the ink outlets so that each ink outlet can supply the same amount of ink to the ink flow path. By further adding a solvent supply pipe connected to the ink supply tube, an air pipe, and a three-way control valve, bubbles generated in the ink supply unit can be removed.

Accordingly, the reliability of the print head can be improved, and the quality and display quality of the color filter formed by using the print head can be improved.

Although described with reference to the embodiments above, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

Claims (5)

A common flow path for supplying ink to the pressure chamber; Piezoelectric elements for providing pressure to the pressure chamber; An injection nozzle for injecting the ink discharged from the pressure chamber to the outside; And An ink supply tube having an ink supply tube into which ink is injected, and an ink supply flow path which moves the injected ink to an ink discharge port and discharges the ink to the common flow path, The ink supply passage includes a bottom surface facing the ink supply tube and having a bottom surface on which the ink discharge port is formed, and triangular sidewalls having rounded edges connecting the bottom surface and the ink supply tube. unit. The ink supply apparatus of claim 1, wherein the ink supply unit A solvent supply pipe connected to the ink supply tube to supply a solvent to the ink supply flow path; And And an air pipe connected to the solvent supply pipe to discharge bubbles from the ink supply flow path to the outside. The ink supply apparatus of claim 2, wherein the ink supply unit And a three-way control valve connected to the ink supply tube, the solvent supply pipe, and the air pipe. The valve of claim 3, wherein the three-way valve A first movement path through which the ink moves to the ink supply passage through the ink supply tube, a second movement path through which the bubble moves through the ink supply tube to the air piping, and the solvent supply piping And a third movement path moving to the ink supply tube through the print head unit. The print head unit according to claim 1, wherein the vertical distance from the bottom surface to the ink supply tube is greater than 0 mm and less than or equal to 2 mm.

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