KR20120007378A - Chemical coating apparatus - Google Patents

Abstract

PURPOSE: A chemical liquid coating device is provided to control the inner pressure of a reservoir and rheological features of chemical liquid. CONSTITUTION: A head(240) has a nozzle surface(242). A body(212) moves in at least one direction. A reservoir(220) receives chemical liquid from a chemical liquid supply source. The reservoir supplies the chemical liquid to nozzles. A heater(250) heats the chemical liquid. A pressure adjusting valve is installed in an air pressure line. A pressure controller receives a temperature value from a temperature sensor(252) in real time. The pressure controller compensates for a change of inner pressure based on a temperature by control of the pressure controller.

Description

Chemical liquid coating device {CHEMICAL COATING APPARATUS}

The present invention relates to a chemical liquid applying apparatus, and more particularly, to a chemical liquid applying apparatus having a reservoir for storing a chemical liquid and having a nozzle for discharging the chemical liquid by an inkjet printing method.

In general, liquid crystal displays display full color, for example, by passing light modulated by the liquid crystal layer through a color filter. The color filter is formed by, for example, arranging filter elements of each color on the R (red), G (green), and B (blue) dots on the surface of the glass substrate in a stripe arrangement, a delta arrangement, or a mosaic arrangement. do.

In the manufacturing process of a liquid crystal display device, in order to manufacture a color filter, an oriented film, etc., a chemical | medical solution is supplied and apply | coated to the surface of a glass substrate. As a chemical liquid applying device for applying such a chemical liquid, there is an ink jet type chemical liquid applying device for discharging and applying the chemical liquid to the surface of a substrate. The chemical liquid applying apparatus applies the chemical liquid by ink jet printing using a plurality of ink jet head units. The inkjet head unit includes a head having a plurality of nozzles which move in various directions with respect to a substrate to supply a chemical liquid. The head receives the chemical liquid from the reservoir for temporarily storing the chemical liquid on the top and discharges the chemical liquid to the surface of the substrate by each of the nozzles.

The reservoir is a chemical solution of R, G or B color, and contains a strong solvent component and stores a highly viscous chemical liquid. The reservoir controls the temperature of the chemical liquid and supplies the chemical liquid to the respective nozzles. For example, an inkjet head discharges a chemical liquid using a piezoelectric piezoelectric element, at which time the reservoir heats the chemical liquid to supply the liquid with low viscosity. To this end, a highly viscous chemical should be applied with a higher piezoelectric element voltage than a less viscous chemical.

In the chemical liquid applying apparatus, the rheological characteristics of the chemical liquid are controlled by varying the characteristics of the material such as a capping agent, the polymer electrolyte type and the amount of addition, so that the rheological characteristics are controlled. Difficult to manage uniformity of discharge.

An object of the present invention is to provide an inkjet head unit capable of precisely controlling the internal pressure of a reservoir and maintaining it constant.

Another object of the present invention is to provide an inkjet head unit capable of controlling the internal pressure of the reservoir and the rheological properties of the chemical liquid according to the temperature change of the chemical liquid.

Another object of the present invention is to provide an inkjet head unit which can improve the discharge uniformity by analyzing the rheological characteristics such as viscosity according to the temperature of the chemical liquid and applying it to the discharge waveform control.

The objects of the present invention are not limited thereto, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

In order to achieve the above objects, the inkjet head unit of the present invention includes a head having a nozzle surface provided with a plurality of nozzles for ejecting a chemical liquid on the upper surface of the object; A body coupled to one side and movable in at least one direction; A reservoir formed in the body to receive and store the chemical liquid from a chemical liquid supply source and to supply the chemical liquid to the nozzles; A heater installed in the reservoir and heating the chemical liquid; A temperature sensor measuring a temperature of the chemical liquid stored in the reservoir; A pneumatic line connected to the reservoir and provided with a pressure control valve; And a pressure regulator that receives the temperature value from the temperature sensor in real time and controls the pressure regulating valve to compensate for the internal pressure change according to the temperature.

The inkjet head unit of the present invention according to this aspect, further comprises a head control unit for adjusting the discharge amount of the nozzles of the head; The head control unit receives the temperature value from the pressure regulator and analyzes the viscosity change of the chemical liquid according to the temperature to control the discharge amount.

As described above, the present invention can precisely control the internal pressure of the reservoir and can be kept constant, and can control the internal pressure of the reservoir and the rheological characteristics of the chemical liquid according to the temperature change of the chemical liquid, and also according to the temperature of the chemical liquid. Discharge uniformity can be improved by analyzing rheological properties such as viscosity and applying them to discharge waveform control.

The drawings described below are for illustrative purposes only and are not intended to limit the scope of the invention.
1 is a view showing a schematic configuration of a chemical liquid applying apparatus according to the present invention;
FIG. 2 is a perspective view showing the configuration of the inkjet printing unit shown in FIG. 1; FIG.
3 is a plan view of the inkjet printing unit shown in FIG. 2;
4 is a perspective view showing the configuration of the inkjet head unit shown in FIG. 1;
5A and 5B are views showing the front and rear configurations of the inkjet head unit shown in Fig. 4;
6 is a block diagram showing a pressure regulator and a liquid crystal supply unit connected to the inkjet head unit.
7A is a graph showing a change in viscosity and pressure with a temperature change of a liquid crystal.
7B is a graph showing a change in volume of the discharge drop by controlling the viscosity of the liquid crystal due to the temperature change of the liquid crystal.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention. The problem, the problem solving means, and effects to be solved by the present invention described above will be easily understood through embodiments related to the accompanying drawings. Each drawing is partly or exaggerated for clarity. In adding reference numerals to the components of each drawing, it should be noted that the same components are shown with the same reference numerals as much as possible, even if displayed on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 7B.

1 is a view showing a schematic configuration of a chemical liquid applying apparatus according to the present invention.

Referring to FIG. 1, a chemical liquid applying apparatus 100 is a facility for applying a chemical liquid to an upper surface of an object by an inkjet method, and includes an inkjet printing unit 110 according to the present invention. The object may be a rectangular flat plate, for example, a glass substrate for manufacturing a color filter, an alignment film, or the like of a liquid crystal display panel, a printed circuit board for forming a metal thin film on a circuit pattern, and And a plate for printing the chemical liquid by an inkjet method. In the embodiment of the present invention will be described in detail using a glass substrate (S) for producing a color filter as an object.

The chemical liquid applying apparatus 100 draws a substrate from an inkjet printing unit 110 that prints a substrate surface by an inkjet method, a loader 102 on which a plurality of substrates are loaded, and the loader 102 and inkjet printing. An index 106 for supplying the unit 110, a baker and oven 108 for receiving and baking a substrate coated with a chemical liquid from the index 106, and an unloader for loading the baked substrate. (unloader) 104. The index 106 is equipped with a transfer robot (not shown) for transferring a substrate between the loader 102, the inkjet printing unit 110, the baking unit 108, and the unloader 104.

The chemical liquid applying apparatus 100 includes a chemical liquid supply unit 105 for supplying a chemical liquid to the inkjet printing unit 110. Moreover, the chemical | medical agent application apparatus 100 is a full-length control part, and is equipped with the main control part 101 which controls the general operation | movement of the chemical | medical solution application apparatus 100. As shown in FIG.

The chemical liquid applying apparatus 100 of the present invention discharges the chemical liquid to the surface of the substrate using a plurality of inkjet head units 210 of FIG. 2. The inkjet head unit 210 is provided as an inkjet head provided with a buffer space therein.

Specifically, FIGS. 2 and 3 are diagrams showing the configuration of the inkjet printing unit.

2 and 3, the inkjet printing unit 110 is an apparatus for applying a chemical liquid to the surface of the substrate S by an inkjet method, and includes a steel base 116 and a stage disposed on the base 116. And a head assembly 200 having a plurality of inkjet head units 210 (210a to 210c) disposed on the stage 112 and applying a chemical to a surface of the substrate S mounted on the stage 112. And a gantry 114 supporting the head assembly 200. In addition, the inkjet printing unit 110 includes a plurality of dustproof members 113 for blocking vibration between the base 116 and the stage 112.

The head assambly 200 is provided as a multi head array (MHA) unit. The head assembly 200 is coupled to a plurality of inkjet head units 210 (210a to 210c) for discharging a chemical liquid by an inkjet method, a bracket 202 on which the inkjet head units 210 are installed, and a bracket 202. And a drive unit 204 for moving the head assembly 200 in at least one direction.

For example, a plurality of inkjet head units 210 are installed in two rows on the front and rear surfaces of the bracket 202. That is, a plurality of inkjet head units 210 are arranged side by side on both front and rear sides of the bracket 202 in the Y-axis direction. Each of the inkjet head units 210 is connected to a chemical supply unit 105 of FIG. 1 to receive chemicals. Each of the inkjet head units 210 may be supplied with the same or different chemicals.

The inkjet head unit 210 is a device for discharging the chemical liquid to the surface of the substrate (S), each of the inkjet head unit 210 has a head (240 in FIG. 4).

When the object is the substrate S for the color filter, the inkjet head units 210 supply one of the R, G, and B color chemicals, respectively. At this time, the chemical liquids are inks of R color, G color, and B color. The inkjet head units 210 for supplying the R, G, and B color chemicals, respectively, are disposed adjacent to each other. The inkjet head units 210 are installed at regular intervals on the bracket 202. The inkjet head units 210 are provided to be adjustable in the bracket 202. In this case, at least three inkjet head units 210 are provided. The inkjet head units 210 are provided in one group of three to supply different chemical liquids, respectively, and are provided in a plurality of groups. A detailed configuration of the inkjet head unit 210 will be described in detail with reference to FIGS. 4 to 5B.

The driving unit 204 is coupled to the bracket 202 on which the inkjet head units 210 are installed, and the first guide members 150 and 152 and the head assembly 200 to move the head assembly 200 in the first direction. It includes a second guide member 206 and a driving unit (not shown) for moving the in the second direction. The drive unit 204 is moved along the gantry 114 in a first direction (ie, Y axis) or in a second direction (ie, X axis). The drive unit 204 also moves the head assembly 204 in a third direction (ie, Z axis). In addition, the driving unit 204 rotates about the central axis of each of the inkjet head units 210.

The stage 112 is provided as a stone plate, the chucking unit 120 is disposed on the upper side and chucking the substrate S, and the cleaning unit 130 is disposed on the other side to clean the head assembly 200. , 140). The chucking unit 120 linearly moves toward the index 106 to receive the substrate S. When the substrate S is seated, the chucking unit 120 chucks to move to the opposite side of the index 106, that is, to a position to apply the chemical to the substrate S. It includes a chuck 124, a chuck driver 126 for moving or rotating the chuck 124 in at least one linear direction, and a third guide member 122 for guiding the chuck 124 in a linear movement. The chuck 124 has a lower portion coupled to the chuck driver 126 and linearly moved along the third guide member 122 in the Y axis direction.

In addition, the stage 112 is provided with first guide members 150 and 152 corresponding to both ends of the gantry 114. The first guide members 150 and 152 extend along the Y axis direction to have the same width as the stage 112. The first guide members 150 and 152 are elongated at the upper ends of the stage 112 along the Y axis direction to linearly move the gantry 114 in the Y axis direction.

The gantry 114 is coupled to the driving unit 204 on one side and the slider 154 is coupled to both lower sides to move the head assembly 200 in the Y-axis or X-axis direction. To this end, the gantry 114 drives the second guide member 206 and the driving unit 204 to move along the second guide member 206 so that the head assembly 200 is linearly moved in the X axis direction. (Not shown) (for example, a motor, a gear, a pulley, a belt, a ball screw, a linear motor) and the like. An upper side of the gantry 114 is provided with a head control unit 118 for controlling the operation of the inkjet printing unit 110, for example, the overall operation, such as chemical liquid discharge. The gantry 114 has the same width as the stage 112 in the X axis direction. That is, the gantry 114 is coupled to the slider 154 at both ends thereof, and the slider 154 is provided to be movable in the Y axis direction along the first guide members 150 and 152. In addition, the gantry 114 linearly moves the driving unit 204 in the X axis direction to move the head assembly 200 in the X axis direction.

The chemical liquid applying apparatus 100 moves the head assembly 200 to a position 200a corresponding to the cleaning units 130 to 140 in order to clean the inkjet head unit 210.

That is, the maintenance zones 130 to 140 may include a first cleaning unit 130 for first cleaning the plurality of inkjet head units 210, and a nozzle surface through which chemical liquids of the inkjet head units 210 are discharged. And a second cleaning unit 140 for secondary cleaning 242.

The first cleaning unit 130 collects a plurality of blades (132 of FIG. 3) for removing the chemical liquid remaining on the nozzle surface 242 in a non-contact manner, and the chemical liquid removed by the blades 132. It includes a purge tank (134). In addition, the purge tank 134 is located in the upper portion of the first cleaning unit 130, the inkjet head unit 210, in order to prevent the nozzles are clogged by the chemical liquid, and pressurized the internal pressure of the inkjet head unit 210 When the remaining chemical liquids are discharged therein, the discharged chemical liquids are collected. The blades 132 are installed on top of the purge tank 134. The blades 132 are provided in plural in correspondence with the inkjet head unit 210. The blade 132 removes the chemical liquid in a non-contact manner with the nozzle surface 242 in order to remove the chemical liquid formed on the nozzle surface 242 of the inkjet head unit 210.

The second cleaning unit 140 cleans the nozzle surface 242 from which the chemical liquid is removed from the first cleaning unit 130 by using a roll type wiper 142. In cleaning, the wiper 142 is in contact with the nozzle face 242. To this end, the second cleaning unit 140 includes a plurality of rollers for rotating the wiper 142 and the contact portion of the wiper 142 in the direction of the nozzle surface 242 when the wiper 142 contacts the nozzle surface 242. Lifting sponges (not shown) and drive devices (not shown) for driving wipers, sponges, and the like (eg, motors, cylinders, etc.).

When the head assembly 200 is moved in the X-axis direction by the driving unit 204 and moved to the other side of the stage 112, the cleaning units 130 to 140 firstly inkjet the upper portion of the first cleaning unit 130. The head unit 210 moves in the Y axis direction to be positioned. The inkjet head unit 210 removes the chemical liquid on the nozzle surface 242 by the blade 132 by linearly moving while maintaining a predetermined interval on the blade 132. At this time, the chemical liquid removed from the nozzle surface 242 is collected in the purge tank 134. Subsequently, the inkjet head unit 210 is moved in the Y axis direction and positioned above the second cleaning unit 140. The wiper 142 of the second cleaning unit 140 is brought into contact with the nozzle face 242 of the inkjet head unit 210, and the wiper 142 is rotated to clean the nozzle face 242.

In addition, the head controller 118 controls a plurality of piezoelectric elements (not shown) to supply the chemical liquid evenly from each nozzle when the chemical liquid is supplied. That is, the head control unit 118 adjusts the applied voltage to the piezo piezoelectric elements corresponding to the nozzles, and evenly controls the discharge amount of each nozzle.

4 to 5B are diagrams showing the configuration of the inkjet head unit according to the embodiment of the present invention.

Referring to FIG. 4, the inkjet head unit 210 includes a body 212, a reservoir (reservoir or buffer tank) 220 storing chemicals in the body 212, and a chemical solution from the reservoir 220. Head 240 for dispensing the chemical solution on the substrate surface, the coupling member 214 for coupling the body 212 to one side of the bracket (202 of Figure 1), the reservoir 220 is installed to heat the chemical liquid A heater 250. In addition, the inkjet head unit 210 includes at least one sensor 230 for detecting the level of the chemical liquid stored in the reservoir 220 and a temperature sensor 252 for measuring the temperature of the chemical liquid.

Body 212 is a head 240 is disposed on the lower surface, is coupled to the bracket 202 to be movable in at least one direction. Body 212 is provided with a reservoir 220 at the bottom inside.

The head 240 has a nozzle surface 242 provided with a plurality of nozzles (not shown) for supplying a chemical liquid to the substrate S on a lower surface opposite the substrate surface seated on the chuck 124. One nozzle surface 242 may be provided with, for example, 128 or 256 nozzles (not shown). The nozzles (not shown) may be arranged in a row at intervals of a predetermined pitch. The nozzles (not shown) may discharge the liquid crystal in an amount of μg.

In the case of the point dotting method using a conventional syringe, since the discharge pitch of the liquid crystal is large and the amount of the liquid crystal discharged is in mg unit, the liquid crystal does not spread evenly on the substrate due to the viscous flow resistance of the liquid crystal. There was a problem. However, in the present invention, since the liquid crystal is discharged in μg units through a plurality of nozzles (not shown) having a narrow pitch interval, the liquid crystal may be more evenly applied onto the substrate despite the viscous flow resistance of the liquid crystal.

Each head 240 may be provided with a number of piezoelectric elements corresponding to nozzles (not shown), and the droplet discharge amount of the nozzles (not shown) may be controlled by controlling the voltage applied to the piezoelectric elements. Each can be adjusted independently.

The reservoir 220 serves as a buffer tank of the chemical liquid. That is, the reservoir 220 is formed in the body 212 to receive and store the chemical liquid from the chemical liquid supply unit 105 and supply the chemical liquid to the nozzles. The reservoir 220 penetrates the sensors 230: 232 ˜ 236 in the center of the upper wall 215 to sense the level of the chemical liquid stored therein.

5A and 5B, a cover 211 made of a transparent material may be coupled to and sealed on the front surface of the reservoir 220 to monitor the inside thereof. In addition, a plurality of piezoelectric elements (not shown) for adjusting the flow rate of the chemical liquid discharged from the nozzles of the head 240 and an interface unit 213 for interfacing with the nozzles are coupled to the rear surface of the reservoir 220. do. The interface unit 213 is electrically connected to the head control unit 118 installed at the upper end of the gantry 114.

Referring to FIG. 6, the head control unit 118 is electrically connected to the inkjet head unit, and applies a control signal to the inkjet head unit. The inkjet head unit is provided with a number of piezoelectric elements corresponding to the nozzles, and the head control unit 118 controls the liquid discharge amount of the nozzles by controlling the voltage applied to the piezoelectric elements.

The lower surface 217 of the reservoir 220 has first and second outlets 222 and 224 for supplying chemical liquids to the nozzles on both sides thereof, and are formed in the lower surface 217 to form the nozzles and the first and second nozzles. And a flow path 228 connecting the second outlets 222 and 224. Therefore, the nozzles are supplied with the chemical liquid from the reservoir 220 through the flow path 228. In addition, the lower surface 217 of the reservoir 220 is provided with a step so that the first and second outlets 222 and 224 have different heights. This is to easily remove bubbles contained in the chemical liquid stored in the reservoir 220 by using the pressure difference between the first and second outlets 222 and 224.

In addition, the rear surface of the reservoir 220 is provided with a first connection portion 216 for adjusting the internal pressure, and a second connection portion 218 for supplying a chemical solution. The first connector 216 is disposed above the reservoir 220 to stably control the pressure. Since the pressure is stabilized and disposed at the upper portion of the first connection portion 216, the phenomenon in which the chemical liquid flows back to the first connection portion 216 and the pneumatic line 262 may be eliminated.

The pressure regulator 260 is connected to the first connector 216, and the liquid crystal supply 270 is connected to the second connector 218.

6 is a block diagram showing a pressure regulator and a liquid crystal supply unit connected to the inkjet head unit.

Referring to FIG. 6, the pressure regulating unit 260 is a pneumatic line 262 provided with a pressure regulating valve 264 which is a servo valve (servo v / v) to control the internal pressure of the reservoir 220 to be kept constant. And a pressure regulator 266 for controlling the pressure regulating valve 264 by receiving feedback of the internal pressure condition of the reservoir 220 according to the heating in real time with an analog signal. The pressure regulator 266 receives the temperature value measured by the temperature sensor 252 in real time and controls the pressure regulating valve 264 to compensate for the internal pressure of the reservoir 220 according to the temperature change. do. Figure 7a shows the viscosity and pressure change with the temperature change of the liquid crystal. The pressure regulator may include a Meniscus Pressure Control (MPC) unit to regulate the internal pressure.

That is, the pressure regulator 260 controls the pressure regulating valve 264 by reflecting the internal pressure increase (change) caused by the temperature rise of the liquid crystal (chemical liquid) stored in the reservoir 220. The pneumatic line 262 is connected to the first connection portion 216 of the reservoir 220.

Meanwhile, the head controller 118 receives the temperature change signal of the liquid crystal from the pressure regulator 266 of the pressure regulator 260, and controls the voltage applied to the piezoelectric elements in consideration of the viscosity change of the liquid crystal according to the temperature change. To adjust the droplet discharge amount of the nozzles. Referring to FIG. 7B, the change in the volume of the liquid crystal is confirmed by controlling the viscosity of the liquid crystal according to the temperature change of the liquid crystal, and the drop volume of the pl unit discharged by linearly changing is applied at the time of setting the waveform condition. Waveform control is possible by the tendency of.

As such, since the temperature is changed by a heater installed in the reservoir 220, the injection pressure of the head can be improved because the waveform can be controlled by changing the discharge volume by controlling the internal pressure of the reservoir and the rheological characteristics of the liquid crystal.

The liquid crystal supply unit 170 includes a liquid crystal supply source 272, a pressing member 274, and a liquid crystal supply line 275. The liquid crystal source 272 may be provided in a cylindrical shape, for example, and the liquid crystal source 272 is filled with a liquid crystal. The pressurizing member 274 exerts a gas pressure on the liquid crystal source 272. The liquid crystal in the liquid crystal source 272 is transmitted to the reservoir 220 through the liquid crystal supply line 275 by the gas pressure of the pressing member 274. The particle filtration member 276 and the bubble filtration member 277 are provided in the liquid crystal supply line 275. One end of the liquid crystal supply line 275 is connected to the liquid crystal supply source 272, and the other end of the liquid crystal supply line 275 is connected to the second connector 218 of the reservoir 220.

The sensors 230 detect the level of the chemical liquid stored in the reservoir 220. The sensors 230 are provided with first and second level sensors 232, 234. The first level sensor 232 detects the water level for supplying the chemical liquid of the reservoir 220, and the second level sensor 234 detects the water level for stopping supply of the chemical liquid. For example, the first and second level sensors 232 and 236 measure the temperature of the chemical liquid to detect the level of the chemical liquid inside the reservoir 220.

The first and second level sensors 232 and 234 penetrate the upper wall 215 of the reservoir 220 to have a step L corresponding to the water level difference. Each of the first and second level sensors 232 and 234 is provided with a terminal 236 outside the upper wall 215 of the reservoir 220, thereby electrically connecting the head control unit 118.

In the above, the configuration and operation of the inkjet head unit and the chemical liquid applying apparatus having the same according to the present invention have been shown in accordance with the detailed description and the drawings, which are merely described by way of example, and do not depart from the spirit of the present invention. Various changes and modifications are possible within the scope.

Explanation of symbols on the main parts of the drawings
100: chemical liquid applying apparatus 110: inkjet printing unit
112: stage 114: gantry
120: chucking unit 130: first cleaning unit
140 second cleaning unit 200 head assembly
210: inkjet head unit 220: reservoir
230: sensor 240: head

Claims (2)

In the inkjet head unit:
A head having a nozzle surface provided with a plurality of nozzles for discharging the chemical liquid on the upper surface of the object;
A body coupled to one side and movable in at least one direction;
A reservoir formed in the body to receive and store the chemical liquid from a chemical liquid supply source and to supply the chemical liquid to the nozzles;
A heater installed in the reservoir and heating the chemical liquid;
A temperature sensor measuring a temperature of the chemical liquid stored in the reservoir;
A pneumatic line connected to the reservoir and provided with a pressure control valve;
And a pressure regulator configured to receive the temperature value from the temperature sensor in real time and control the pressure regulating valve to compensate for the internal pressure change according to the temperature. The method of claim 1,
Further comprising a head control unit for adjusting the liquid discharge amount of the nozzles of the head;
The head control unit receives the temperature value from the pressure regulator, the inkjet head unit, characterized in that for controlling the discharge amount by analyzing the viscosity change of the chemical liquid according to the temperature.

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