KR20140141411A - Liquid dispensing apparatus and substrate treating apparatus including the apparatus - Google Patents

Abstract

Disclosed is an apparatus to discharge chemicals including: a head having nozzles to discharge chemicals to a substrate in an inkjet method; a reservoir having a reservoir space to store chemicals inside to supply chemicals to the head; and a pressure controlling unit to control the pressure of the reservoir space. The pressure controlling unit includes: a pressure controller; a pneumatic line to connect the pressure controller with the reservoir; and a buffer box provided on the pneumatic line, and having a buffer space with a cross sectional area larger than a flow path inside the pneumatic line.

Description

TECHNICAL FIELD [0001] The present invention relates to a chemical liquid ejecting apparatus and a substrate processing apparatus including the liquid ejecting apparatus.

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a chemical liquid ejecting apparatus, and more particularly to an apparatus for ejecting liquid crystal on a substrate by an ink-

2. Description of the Related Art Recently, liquid crystal display devices have been widely used in display portions of electronic apparatuses such as mobile phones and portable computers. The liquid crystal display device has a structure in which a liquid crystal is injected into a space between a color filter substrate on which a black matrix, a color filter, a common electrode and an alignment film are formed, and an array substrate on which a thin film transistor (TFT) To obtain a visual effect.

In a manufacturing process of a liquid crystal display device, a chemical liquid is supplied and coated on the surface of a glass substrate in order to manufacture a color filter, an alignment film, and the like. The chemical liquid application device for applying such a chemical liquid includes an inkjet chemical liquid application device for ejecting the chemical liquid onto the surface of the substrate and applying the chemical liquid. This chemical solution applying apparatus applies a chemical solution by an inkjet printing method using a plurality of inkjet head units. The inkjet head unit includes a head having a plurality of nozzles that move in various directions with respect to a substrate to supply a chemical solution. The head receives the chemical liquid from the reservoir which temporarily stores the chemical liquid on the upper side, and discharges the chemical liquid onto the surface of the substrate by each of the nozzles.

Korean Patent Laid-Open No. 10-2012-0007378 discloses such a chemical liquid application device. The chemical liquid is supplied from the liquid crystal source to the reservoir by the gas pressure, and is discharged to the substrate surface through the nozzles of the head via the reservoir.

During the supply of the chemical liquid from the liquid crystal source to the reservoir, waves are generated in the reservoir due to the pressure change and the water level fluctuation. These pulses generate backflow of the chemical liquid through the pneumatic line, and the countercurrent chemical liquid flows into the pressure regulator and damages the pressure regulator. In order to prevent damage to the pressure regulator, a sensor for detecting the backflow of the chemical liquid and a valve for shutting off the pneumatic line when the backflow of the chemical liquid is provided are provided. However, the response speed of the valve does not reach the backflow rate of the chemical liquid, do.

The present invention provides a chemical liquid ejection apparatus capable of preventing damage to a pressure controller due to backflow of a chemical liquid.

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.

According to an embodiment of the present invention, a chemical liquid ejecting apparatus includes a head having nozzles for ejecting a chemical liquid into a substrate by an inkjet method; Wherein a reservoir space for storing a chemical solution is formed inside the reservoir, and a reservoir for supplying a chemical solution to the head; And a pressure control unit for controlling a pressure of the reservoir space, wherein the pressure control unit comprises: a pressure controller; A pneumatic line connecting the pressure controller and the reservoir; And a buffer box provided on the pneumatic line and formed with a buffer space having a larger cross-sectional area than the flow path in the pneumatic line.

In addition, the buffer space may have a larger volume per unit length than the flow path of the pneumatic line.

Further, the pressure control unit may include a backflow sensor that senses backflow of the chemical liquid to the pressure controller side; A pressure control valve installed in the pneumatic line in a section between the pressure controller and the buffer box; And a valve control unit for controlling the pressure control valve so that the chemical solution does not flow to the pressure controller when the backflow sensor detects the backflow of the chemical solution.

In addition, the backflow monitoring sensor can detect the backflow of the chemical liquid through the buffer space.

The valve control unit may block the flow path of the pneumatic line by closing the pressure control valve when the backflow of the chemical liquid is detected.

Further, the pressure control valve may be a three-way valve, and the pressure control unit may further include a bypass line connected to the pressure control valve and branched from the flow path of the pneumatic line, The pressure control valve may be controlled so that the flow of the chemical liquid is shut off to the pressure controller side and the chemical liquid is discharged to the bypass line side.

The pressure control unit further includes a bypass line connected to the buffer box and having a discharge valve. The valve control unit may open the discharge valve when the backflow of the chemical liquid is sensed.

The pressure control unit may further include a filter installed in the pneumatic line in a section between the pressure controller and the pressure control valve.

Also, the buffer box may be provided at the front end of the pneumatic line adjacent to the reservoir.

The buffer box may also be provided at the rear end of the pneumatic line adjacent to the pressure controller.

According to an embodiment of the present invention, a substrate processing apparatus includes a substrate supporting unit on which a substrate is placed; A gantry provided on a moving path of the substrate supporting unit and movable in one direction; A plurality of heads mounted on the gantry and having nozzles for ejecting a chemical liquid onto the substrate by an inkjet method; Wherein a reservoir space for storing a chemical solution is formed inside the reservoir, and a reservoir for supplying a chemical solution to the head; And a pressure control unit for maintaining the reservoir space at a negative pressure, wherein the pressure control unit comprises: a pressure controller; A pneumatic line connecting the pressure controller and the reservoir; And a buffer box provided on the pneumatic line, wherein a buffer space having a larger volume per unit length than the flow path in the pneumatic line is formed.

Further, the pressure control unit may include a backflow sensor that senses backflow of the chemical liquid to the pressure controller through the buffer space; A pressure control valve installed in the pneumatic line in a section between the pressure controller and the buffer box; And a valve control unit for controlling the pressure control valve so that the chemical solution does not flow to the pressure controller when the backflow sensor detects the backflow of the chemical solution.

Further, the pressure control valve may be a three-way valve, and the pressure control unit may further include a bypass line connected to the pressure control valve and branched from the flow path of the pneumatic line, The pressure control valve may be controlled so that the flow of the chemical liquid is shut off to the pressure controller side and the chemical liquid is discharged to the bypass line side.

The pressure control unit further includes a bypass line connected to the buffer box and having a discharge valve. The valve control unit may open the discharge valve when the backflow of the chemical liquid is sensed.

Also, the buffer box may be provided at the front end of the pneumatic line adjacent to the reservoir.

The buffer box may also be provided at the rear end of the pneumatic line adjacent to the pressure controller.

According to the embodiments of the present invention, since the time for the chemical solution to flow back to the pressure controller is increased by the provision of the buffer box, the chemical solution can be prevented from flowing into the pressure controller.

1 is a view showing a configuration of an inkjet type liquid crystal coating equipment according to an embodiment of the present invention.
2 is a perspective view of the liquid crystal discharge portion of FIG.
3 is a plan view of the liquid crystal discharge portion of FIG.
Fig. 4 is a view showing the first drive unit of Fig. 3. Fig.
FIG. 5 is a view showing the second drive unit of FIG. 3. FIG.
6 is a view showing a linear movement and a rotation process of the gantry.
Fig. 7 is a side view of the head moving unit of Figs. 2 and 3. Fig.
Figure 8 is a front view of the first mobile unit of Figure 7;
9 and 10 are views illustrating the configuration of an inkjet head unit according to an embodiment of the present invention.
11 is a view showing a liquid crystal supply unit and a pressure control unit connected to an inkjet head unit according to an embodiment of the present invention.
12 to 15 are views showing a liquid crystal supply unit and a pressure control unit connected to an inkjet head unit according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The above and other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. Each drawing has been partially or exaggerated for clarity. It should be noted that, in adding reference numerals to the constituent elements of the respective drawings, the same constituent elements are shown to have the same reference numerals as possible even if they are displayed on different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Hereinafter, an apparatus for applying a chemical liquid to an object by an inkjet method will be described.

For example, the object may be a color filter (CF) substrate or a thin film transistor (TFT) substrate of a liquid crystal display panel. The chemical liquid may be a liquid crystal, an alignment liquid, red (R) Green (G), or blue (B) ink. As the alignment liquid, polyimide may be used.

The alignment liquid can be applied to the entire surface of the color filter (CF) substrate and the thin film transistor (TFT) substrate, and the liquid crystal can be applied to the entire surface of the color filter (CF) substrate or the thin film transistor (TFT) substrate. The ink may be applied to the interior area of the black matrix arranged in a lattice pattern on a color filter (CF) substrate.

In this embodiment, a facility using liquid crystal as a chemical liquid is described as an example, but the technical idea of the present invention is not limited thereto.

1 is a view showing a configuration of an inkjet type liquid crystal coating equipment. The liquid crystal coating equipment 1 shown in Fig. 1 is a facility for applying a liquid crystal to a substrate by an inkjet method for discharging droplets.

The substrate may be a color filter (CF) substrate or a thin film transistor (TFT) substrate of a liquid crystal display panel, and the liquid crystal may be applied to an entire surface of a color filter (CF) substrate or a thin film transistor (TFT) substrate.

1, the liquid crystal coating equipment 1 includes a liquid crystal discharge unit 10, a substrate transfer unit 20, a loading unit 30, an unloading unit 40, a liquid crystal supply unit 50, and a main controller 90 ). The liquid crystal discharge portion 10 and the substrate transfer portion 20 are arranged in a line in the first direction I and can be positioned adjacent to each other. A liquid crystal supply part 50 and a main control part 90 are disposed at positions facing the substrate transfer part 20 with the liquid crystal discharge part 10 as a center. The liquid crystal supply part 50 and the main control part 90 may be arranged in a line in the second direction II. The loading unit 30 and the unloading unit 40 are disposed at positions facing the liquid crystal discharge unit 10 with the substrate transfer unit 20 as a center. The loading section 30 and the unloading section 40 may be arranged in a line in the second direction II.

Here, the first direction I is an arrangement direction of the liquid crystal discharge portion 10 and the substrate transfer portion 20, the second direction II is a direction perpendicular to the first direction I on the horizontal plane, (III) is a direction perpendicular to the first direction (I) and the second direction (II). The substrate to which the liquid crystal is to be applied is brought into the loading section 30. The substrate transferring unit 20 transfers the substrate loaded into the loading unit 30 to the liquid crystal discharging unit 10. The liquid crystal discharging portion 10 receives liquid crystal from the liquid crystal supplying portion 50 and discharges the liquid crystal onto the substrate by an ink jet method for discharging liquid droplets. When the liquid crystal discharge is completed, the substrate transfer section 20 transfers the substrate from the liquid crystal discharge section 10 to the unloading section 40. The substrate coated with the liquid crystal is taken out of the unloading portion 40. The main control unit 90 controls the overall operations of the liquid crystal discharge unit 10, the substrate transfer unit 20, the loading unit 30, the unloading unit 40, and the liquid crystal supply unit 50.

FIG. 2 is a perspective view of the liquid crystal discharge portion of FIG. 1, and FIG. 3 is a plan view of the liquid crystal discharge portion of FIG. 2 and 3, the liquid crystal discharging portion 10 includes a base B, a substrate supporting unit 100, a gantry 200, a gantry moving unit 300, inkjet head units 400, Unit 500, a liquid crystal supply unit 600, a pressure control unit 700, a liquid crystal discharge amount measurement unit 800, a nozzle inspection unit 900, and a head cleaning unit 1000.

Hereinafter, each configuration of the liquid crystal discharge portion will be described in detail.

The base (B) may be provided in a rectangular parallelepiped shape having a constant thickness. A substrate supporting unit 100 is disposed on the upper surface of the base B. The substrate supporting unit 100 has a supporting plate 110 on which the substrate S is placed. The support plate 110 may be a rectangular plate. The rotation driving member 120 is connected to the lower surface of the support plate 110. The rotation drive member 120 may be a rotary motor. The rotation driving member 120 rotates the support plate 110 around a rotation center axis perpendicular to the support plate 100. [

When the support plate 110 is rotated by the rotation drive member 120, the substrate S can be rotated by the rotation of the support plate 110. [ When the long-side direction of the cell formed on the substrate to which the liquid crystal is to be applied faces the second direction II, the rotation driving member 120 can rotate the substrate such that the long-side direction of the cell is in the first direction I.

The support plate 110 and the rotation driving member 120 may be linearly moved in the first direction I by the linear driving member 130. The linear driving member 130 includes a slider 132 and a guide member 134. The rotation driving member 120 is provided on the upper surface of the slider 132. [ The guide member 134 is elongated in the first direction I in the center of the upper surface of the base B. A linear motor (not shown) may be incorporated in the slider 132 and the slider 132 is linearly moved in the first direction I along the guide member 134 by a linear motor (not shown).

The gantry 200 is provided at an upper portion of a path through which the support plate 110 is moved. The gantry 200 is disposed upwardly away from the upper surface of the base B and the gantry 200 is arranged such that its longitudinal direction is in the second direction II. The inkjet head unit 400 is coupled to the gantry 200 by the head moving unit 500. The inkjet head unit 400 can be linearly moved by the head moving unit 500 in the longitudinal direction of the gantry, that is, in the second direction II, and linearly in the third direction III.

The gantry moving unit 300 moves the gantry 200 in a first direction I or moves the gantry 200 in such a direction that the longitudinal direction of the gantry 200 is inclined in the first direction I . By the rotation of the gantry 200, the nozzles (not shown) of the inkjet head unit 400 are aligned in an oblique direction in the first direction I.

The gantry moving unit 300 can rotate the other end of the gantry 200 with the one end of the gantry 200 as the center of rotation as will be described below. Alternatively, the gantry moving unit 300 may be configured to rotate the gantry 200 with the center of the gantry 200 as the center of rotation. The gantry drive unit 300 includes a first drive unit 310 and a second drive unit 320.

The second drive unit 320 is provided at one end of the gantry 200 serving as a rotation center, and the first drive unit 310 is provided at the other end of the gantry 200.

Fig. 4 is a view showing the first drive unit of Fig. 3. Fig. Referring to FIG. 4, the first drive unit 310 includes a slider 312, a first rotation support member 314, and a first linear drive member 318. A guide rail 210 is provided along the longitudinal direction of the gantry 200 at the lower end of the other end of the gantry 200. The slider 312 is guided by the guide rail 210 and linearly moved. The first rotation support member 314 is coupled to the lower end of the slider 312. The first rotation support member 314 may be a bearing capable of relative rotation between the upper and lower portions. A first linear driving member 318 is coupled to the lower surface of the first rotation support member 314. The first linear driving member 318 linearly moves the first rotation supporting member 314 in the first direction I.

The first linear driving member 318 includes a guide rail 315 and a slider 317. The guide rail 315 is disposed in the other side edge of the upper surface of the base B with the guide member 134 of the substrate supporting unit 100 as the center, with the longitudinal direction thereof facing the first direction I. A slider 317 is movably coupled to the guide rail 315. The first rotation support member 314 is coupled to the upper surface of the slider 317. The slider 317 may include a linear motor (not shown). The slider 317 linearly moves in the first direction I along the guide rail 315 by the driving force of a linear motor (not shown).

FIG. 5 is a view showing the second drive unit of FIG. 3. FIG. 5, the second driving unit 320 linearly moves one end of the gantry 200 in the first direction I when the gantry 200 is linearly moved. When the gantry 200 is rotated, As shown in Fig.

The second drive unit 320 includes a second rotation support member 324 and a second linear drive member 328. A connecting member 322 is coupled to a lower end of the gantry 200 and a second rotation supporting member 324 is coupled to a lower surface of the connecting member 322. The second rotation support member 324 may be a bearing capable of relative rotation between the upper and lower portions. And a second linear driving member 328 is coupled to a lower surface of the second rotation supporting member 324. [ The second linear driving member 328 linearly moves the second rotation supporting member 324 in the first direction I. The connection member 322 and the one end of the gantry 200 are linearly moved by the linear movement of the second rotation support member 324.

The second linear drive member 328 includes a guide rail 325 and a slider 327. The guide rail 325 is disposed in one side edge portion of the upper surface of the base B about the guide member 134 of the substrate supporting unit 100 with its longitudinal direction directed in the first direction I. A slider 327 is movably coupled to the guide rail 325. And the second rotation support member 324 is coupled to the upper surface of the slider 327. [ The slider 327 may include a linear motor (not shown). The slider 327 linearly moves in the first direction I along the guide rail 325 by the driving force of a linear motor (not shown).

6 is a view showing the rotation and linear movement of the gantry. In Figs. 3 and 6, the liquid crystal supply unit is omitted for convenience of illustration.

4, 5 and 6, the gantry 200 is rotated by the first drive unit 310 and the second drive unit 320 so as to be inclined in the first direction I , And can be linearly moved in the first direction (I).

When the first linear driving member 318 of the first driving unit 310 linearly moves in the first direction I in a state where the second linear driving member 328 of the second driving unit 320 is fixed, (200) is rotated. This will be described in detail as follows.

First, the slider 317 of the first linear driving member 318 moves in the first direction I along the guide rail 315 by the driving force of a linear motor (not shown). At this time, one end of the gantry 200 is rotated by the second rotation supporting member 324 in the state where there is no movement in the first direction I because the second linear driving member 328 is not driven.

As the slider 317 of the first linear driving member 318 moves in the first direction I, the first rotation supporting member 314 disposed on the upper portion thereof is moved along the guide rail 315 in the first direction I). At the same time, the slider 312 coupled to the upper end of the first rotation support member 314 is rotated by the relative rotation between the upper and lower portions of the first rotation support member 314, and the guide rail 210 To the other end side of the gantry 200. As a result, the gantry 200 rotates about the supporting position of the second driving unit 320, and the supporting position of the gantry 200 of the first driving unit 310 is shifted to the outside of the other end. Through this operation, the gantry 200 can be rotated in an oblique direction in the first direction I, so that the inkjet head unit 400 is aligned in an inclined direction in the first direction I. As such, when the ink jet head unit 400 is aligned in the oblique direction in the first direction I, the liquid crystal discharge pitch can be flexibly adjusted in accordance with the pixel pitch change of the substrate S to which the liquid crystal is to be applied, It is possible to increase the film uniformity of the liquid crystal applied to the substrate.

The gantry 200 can be rotated in the same manner as described above and the gantry 200 can be rotated in a state where the slider 317 of the first linear driving member 318 and the slider 317 of the second linear driving member 328 327 in the first direction I further. One end of the gantry 200 is linearly moved in the first direction I by the movement of the slider 327 of the second linear driving member 328 and the other end of the gantry 200 is moved in the first direction I by the first linear driving member 318, Can be linearly moved in the first direction (I) by the movement of the slider (317).

When the gantry 200 is fixed and the substrate moves in the first direction I, the substrate can be moved from one side of the gantry 200 to the other side, so that the footprint of the equipment can be increased. However, according to the present invention, since the gantry 200 can be linearly moved in the first direction I with the substrate fixed or with the linear movement of the substrate, the footprint of the facility can be reduced.

The head moving unit 500 may be provided to the inkjet head unit 400, respectively. In the case of this embodiment, since three inkjet head units 400a, 400b and 400c are provided as an example, three head moving units 500 can also be provided corresponding to the number of heads. Alternatively, one head moving unit 500 may be provided, in which case the ink jet head unit 400 can be moved integrally, not individually.

Fig. 7 is a side view of the head moving unit of Figs. 2 and 3, and Fig. 8 is a front view of the first moving unit of Fig.

Referring to FIGS. 7 and 8, the head moving unit 500 includes a first moving unit 520 and a second moving unit 540. The first moving unit 520 linearly moves the inkjet head unit 400a in the longitudinal direction of the gantry, that is, in the second direction II, and the second moving unit 540 moves the inkjet head unit 400a in the third direction (III).

The first moving unit 520 includes guide rails 522a and 522b, sliders 524a and 524b, and a moving plate 526. [ The guide rails 522a and 522b may extend in the second direction II and be spaced apart from the gantry 200 in the third direction III. Sliders 524a and 524b are movably coupled to the guide rails 522a and 522b and linear actuators such as a linear motor (not shown) may be incorporated in the sliders 524a and 524b. The moving plate 526 is coupled to the sliders 524a and 524b. The upper region of the moving plate 526 is coupled to the upper slider 524a and the lower region of the moving plate 526 is coupled to the lower slider 524b. The moving plate 526 linearly moves in the second direction II along the guide rails 522a and 522b by the driving force of a linear motor (not shown) as shown in Fig. Thus, as the inkjet head units 400a, 400b, 400c are individually moved along the second direction II, the gap between the inkjet head units 400a, 400b, 400c can be adjusted.

The second moving unit 540 includes a guide member 542, a slider 544, a detector 546, and a controller 548. The guide member 542 is engaged with the moving plate 526 of the first moving unit 520 and guides the linear movement of the slider 544 in the third direction III. The slider 544 is coupled to the guide member 542 so as to be linearly movable. A linear actuator such as a linear motor (not shown) may be incorporated in the slider 544. The inkjet head unit 400a is coupled to the slider 544 and is moved in the third direction III by the linear movement of the slider 544 in the third direction III.

The detector 546 may be installed in the gantry 200 and detects the distance between the inkjet head unit 400a and the substrate S. [ The detector 546 may be a laser sensor. The controller 548 generates a control signal corresponding to the detection signal of the detector 546 and transmits a control signal to the linear motor built in the slider 544 to control the driving of the linear motor. If it is determined that the interval between the inkjet head unit 400a and the substrate S deviates from a preset reference value in accordance with the detection result of the detector 546, the controller 548 controls the driving of the linear motor (not shown) The distance between the head unit 400a and the substrate S is adjusted.

The inkjet head unit 400 discharges droplets of liquid crystal onto the substrate. A plurality of inkjet head units 400 may be provided. In this embodiment, three inkjet head units 400a, 400b and 400c are provided, but the present invention is not limited thereto. The inkjet head units 400 may be arranged in a line in a row in the second direction II and are coupled to the gantry 200.

A plurality of nozzles (not shown) for ejecting droplets of liquid crystal are provided on the bottom surface of the inkjet head unit 400. For example, 128 or 256 nozzles (not shown) may be provided in each of the heads. The nozzles (not shown) may be arranged in a line at intervals of a predetermined pitch. The nozzles (not shown) can eject the liquid crystal in an amount of μg. In the conventional point dotting method using a syringe, since the ejection pitch of the liquid crystal is large and the amount of liquid crystal to be ejected is in the unit of mg, the liquid crystal is not spread evenly on the substrate due to the viscous flow resistance of the liquid crystal There was a problem. However, since the liquid crystal is ejected in units of micrograms through a plurality of nozzles (not shown) having a narrow pitch interval, the liquid crystal can be coated more evenly on the substrate despite the viscous flow resistance of the liquid crystal.

The number of piezoelectric elements corresponding to the nozzles (not shown) may be provided in each of the inkjet head units 400, and the amount of droplets discharged from the nozzles (not shown) may be controlled by controlling the voltage applied to the piezoelectric elements Respectively.

9 and 10 are views illustrating the configuration of an inkjet head unit according to an embodiment of the present invention. Since the ink jet head units 400a, 400b and 400c have the same configuration, the ink jet head unit 400a will be described below as an example.

9 and 10, the inkjet head unit 400a includes a body 412, a reservoir 420 for storing liquid crystal in the body 412, a reservoir 420, And a coupling member 214 for coupling the body 412 to the front surface of the moving plate 526. The head 440 has a function of receiving the liquid crystal from the liquid crystal display panel 412 and discharging the liquid chemical onto the surface of the substrate. In addition, the inkjet head unit 400a includes sensors 430 that sense the level of the liquid crystal stored in the reservoir 420. [

The body 412 has a head 440 disposed on the lower surface thereof and is coupled with the moving plate 526 so as to be movable in at least one direction. The body 412 is provided with a reservoir 420 at its inner bottom.

The head 440 has a nozzle surface 242 provided with a plurality of nozzles (not shown) for supplying liquid crystal to the substrate S on the lower surface opposite to the substrate surface resting on the support plate 110. One nozzle face 242 may be provided with, for example, 128 or 256 nozzles (not shown). The nozzles (not shown) may be arranged in a line at intervals of a predetermined pitch. The nozzles (not shown) can eject the liquid crystal in an amount of μg.

In the conventional point dotting method using a syringe, since the ejection pitch of the liquid crystal is large and the amount of liquid crystal to be ejected is in the unit of mg, the liquid crystal is not spread evenly on the substrate due to the viscous flow resistance of the liquid crystal There was a problem. However, since the liquid crystal is ejected in units of micrograms through a plurality of nozzles (not shown) having a narrow pitch interval, the liquid crystal can be coated more evenly on the substrate despite the viscous flow resistance of the liquid crystal.

The number of piezoelectric elements corresponding to the nozzles (not shown) may be provided in the head 440, and the amount of liquid droplets discharged from the nozzles (not shown) may be independently controlled by controlling the voltage applied to the piezoelectric elements Lt; / RTI >

The reservoir 420 has a reservoir space 421 in which the liquid crystal is stored therein, serving as a buffer tank for the liquid crystal. The reservoir space 421 is formed inside the body 412 to receive and store the liquid crystal from the chemical liquid supply unit 600 and supply the liquid crystal to the nozzles (not shown).

A cover 411 made of a transparent material is coupled to the front surface of the reservoir 420, and the inside can be monitored. The lower surface 417 of the reservoir 420 has first and second outlets 422 and 424 for supplying the liquid crystal to the nozzles on both sides and a second outlet 422 and 424 formed in the lower surface 417, And a flow path 428 connecting the second outlets 422 and 424. Accordingly, the nozzles are supplied with the liquid crystal from the reservoir 420 through the flow path 428. The lower surface 417 of the reservoir 420 is provided with a step so that the first and second outlets 422 and 424 have different heights. This is to easily remove bubbles contained in the liquid crystal stored in the reservoir 420 using the pressure difference between the first and second outlets 422 and 424. The reservoir 420 is provided at its rear surface with a first connection part 416 to which a pneumatic line for controlling the internal pressure is connected and a second connection part 418 to which a chemical solution supply line for supplying liquid crystal is connected. The first connection portion 416 is disposed above the reservoir 420 to stably control the pressure. The first connection portion 416 is stable in pressure and disposed at the upper portion, thereby eliminating the phenomenon that the liquid crystal flows back to the first connection portion 416 and the pneumatic line.

The reservoir 420 penetrates through the center of the upper wall 415 and senses the liquid level of the liquid crystal stored therein. The sensors 430 are provided with first and second level sensors 432 and 434. The first level sensor 432 senses the level at which the liquid crystal supply of the reservoir 420 is required, and the second level sensor 434 senses the level at which the liquid crystal supply is stopped. For example, the first and second level sensors 432 and 436 measure the liquid crystal temperature and sense the liquid crystal level inside the reservoir 420. The first and second level sensors 432 and 434 pass through the upper wall 415 of the reservoir 420 and are installed to have a level difference L corresponding to the level difference.

A pressure control unit 460 is connected to the first connection unit 416 and a liquid crystal supply unit 600 is connected to the second connection unit 418.

11 is a view showing a liquid crystal supply unit and a pressure control unit connected to an inkjet head unit according to an embodiment of the present invention.

Referring to Fig. 11, the liquid crystal supply unit 600 supplies the liquid crystal to the reservoir space 421. Fig. The liquid crystal supply unit 600 includes a liquid crystal supply source 672, a pressing member 674, and a liquid crystal supply line 675. The liquid crystal supply source 672 may be provided in a cylindrical shape, for example, and the liquid crystal supply source 672 is filled with liquid crystal. The pressing member 674 applies a gas pressure to the liquid crystal supply source 672. The liquid crystal in the liquid crystal supply source 672 is transferred to the reservoir space 421 through the liquid crystal supply line 675 by the gas pressure of the pressure member 674. One end of the liquid crystal supply line 675 is connected to the liquid crystal supply source 672 and the other end is connected to the second connection portion 418 of the reservoir 420. The liquid crystal supply line 675 is provided with a particle filter member 676 and a bubble filter member 677. The particle filter member 676 filters the particles contained in the liquid crystal, and the bubble filtering member 677 removes bubbles contained in the liquid crystal.

The pressure control unit 460 maintains the internal pressure of the reservoir 420 constant. The pressure control unit 460 includes a pressure controller 461, a pneumatic line 463, a buffer box 465, a backflow sensor 467, a pressure control valve 471, and a valve control unit 473.

The pressure controller 461 feedbacks the internal pressure condition of the reservoir 420 according to the heating in real time to control the pressure control valve 471 to compensate for the internal pressure change of the reservoir 420 according to the temperature change. The pressure controller 461 may include a meniscus pressure control (MPC) unit for regulating the pressure of the reservoir space 421. The pressure controller 461 can maintain the internal pressure of the reservoir 420 constant by controlling the positive pressure and the negative pressure.

The pneumatic line 463 connects the pressure controller 461 and the reservoir 420. A flow path is formed inside the pneumatic line 463, and the flow path communicates with the reservoir space 421.

The buffer box 465 is installed on the pneumatic line 463, and a buffer space (not shown) is formed therein. The buffer space has a larger cross-sectional area than the internal flow path of the pneumatic line 463. The buffer space is larger in volume per unit length than the flow path of the pneumatic line 463.

The backflow sensor 467 detects whether backflow of the liquid crystal occurs to the pressure controller 461 side. According to the embodiment, the backflow sensor 467 detects the backflow of the liquid crystal through the inside of the buffer box 461. The backflow sensor 467 may be a volumetric sensor or an optical sensor.

Alternatively, the backflow sensor 467 may detect the backflow of the liquid crystal through the internal flow path of the pneumatic line 463. In this case, the backflow sensor 467 senses the internal flow path of the pneumatic line 463 between the buffer box 461 and the reservoir 420.

A pressure control valve 471 is installed in the pneumatic line 463 in the interval between the pressure controller 461 and the buffer box 465. The pressure control valve 471 can open or close the flow path of the pneumatic line 463 or adjust the degree of opening. The pressure control valve 471 may be a servo valve (servo v / v).

The filter 469 is installed in the pneumatic line 463 in the interval between the pressure sensor 461 and the pressure control valve 471 and filters the liquid crystal flowing back to the pneumatic line 463.

The valve control unit 473 adjusts the pressure control valve 471 so that the liquid crystal does not flow to the pressure controller 461 side when the backflow of liquid crystal is detected. When the backflow sensor 467 detects the occurrence of the backflow of the liquid crystal, the detection signal is transmitted to the valve controller 473. The valve control unit 473 applies an electrical signal to the pressure control valve 471 to switch the pressure control valve 471 to the close state.

When the liquid crystal is supplied from the liquid crystal supply unit 600 to the reservoir space 421, a fluctuation occurs in the reservoir 420 due to a pressure change and a water level fluctuation, thereby causing liquid crystals to flow back into the pneumatic line 463 The phenomenon occurs frequently. The countercurrent liquid crystal flows into the buffer box 465 along the pneumatic line 463. After the liquid crystal sufficiently fills the buffer space, the liquid crystal flows back to the pressure controller 461 side. In this process, the liquid crystal movement time increases toward the pressure controller 461 side. While the liquid crystal fills the buffer space, the backflow sensor 467 detects the back flow of the liquid crystal. Since the buffer space is larger in volume per unit length than the flow path of the pneumatic line 463, a sufficient time is taken for the backflow sensor 467 to sense the back flow of the liquid crystal.

When the backflow of the liquid crystal is detected in the backflow sensor 467, an electrical signal is applied to the pressure control valve 471, and the pressure control valve 471 blocks the pneumatic line 463. The pneumatic line 463 is blocked before the liquid crystal that flows back due to the buffer space reaches the pressure controller 461. [ Therefore, damage of the pressure controller 461 due to backflow of the liquid crystal can be prevented.

12 is a view showing a liquid crystal supply unit and a pressure control unit connected to an inkjet head unit according to another embodiment of the present invention.

Referring to FIG. 12, the pressure control unit 460a further includes a bypass line 475. The bypass line 475 is connected to the pressure control valve 471a and branches from the flow path of the pneumatic line 463. A three-way valve is used as the pressure control valve 471a. Way valve 471a opens the flow path of the pneumatic line 463 to the pressure controller 461 side or closes the flow path of the pneumatic line 463 to the pressure controller 461 side and opens the flow path to the bypass line 475 side .

In normal operation, the pressure control valve 471a opens the flow path of the pneumatic line 463 to the pressure controller 461 side to regulate the internal pressure of the reservoir 420.

The pressure control valve 471a closes the flow path of the pneumatic line 463 to the side of the pressure controller 461 and opens the flow path to the side of the bypass line 473 when the reverse flow detection sensor 467 detects the back flow of the liquid crystal. The buffer box 465 senses the back flow of the liquid crystal and a sufficient time for controlling the pressure control valve 471a is secured. Due to this, the liquid crystal flowing backward is discharged to the outside through the bypass line 475, and does not flow toward the pressure controller 461 side.

13 is a view illustrating a liquid crystal supply unit and a pressure control unit connected to an inkjet head unit according to another embodiment of the present invention.

Referring to Fig. 13, the pressure control unit 460b further includes a bypass line 477 and a discharge valve 479. Fig. The bypass line 477 is directly connected to the buffer box 465. The discharge valve 479 is installed in the bypass line 477 and opens and closes the bypass line 477.

The valve controller 473 controls the pressure control valve 469 and the discharge valve 479, respectively. When the backflow of the liquid crystal is detected in the backflow sensor 467, the valve controller 473 switches the pressure control valve 469 to the closed state and the discharge valve 479 to the open state. It is provided to the buffer box 465 to sense the back flow of the liquid crystal and to secure enough time to control the pressure control valve 469 and the discharge valve 479. [ The liquid crystals flowing backward flow into the buffer box 465 and are simultaneously discharged to the outside through the bypass line 477. The flow of liquid crystal is blocked between the pressure controller 461 and the buffer box 465, so that the process can be restarted without cleaning the pneumatic line 463 due to the liquid crystal attraction.

FIGS. 14 and 15 are views respectively showing a liquid crystal supply unit and a pressure control unit connected to the inkjet head unit according to another embodiment of the present invention.

The buffer box 465a may be provided at the front end of the pneumatic line 463 adjacent to the reservoir 420 as shown in Fig. Alternatively, the buffer box 465b may be provided at the rear end of the pneumatic line 463 adjacent to the pressure controller 461 as shown in Fig. The positions of the buffer boxes 465a and 465b facilitate the maintenance of the pressure control units 460c and 460d.

2 and 3, the liquid crystal discharge amount measurement unit 800 measures the liquid crystal discharge amount of the inkjet head units 400a, 400b and 400c. Specifically, the liquid crystal discharge amount measurement unit 800 measures the amount of liquid crystal discharged from all of the nozzles (not shown) for each of the inkjet head units 400a, 400b and 400c. The presence or absence of abnormality in the nozzles (not shown) of the inkjet head units 400a, 400b and 400c can be confirmed macroscopically by measuring the liquid crystal discharge amount of the inkjet head units 400a, 400b and 400c. That is, when the liquid crystal discharge amount of the inkjet head units 400a, 400b, 400c is out of the reference value, it is found that at least one of the nozzles (not shown) is abnormal.

The inkjet head units 400a, 400b and 400c are moved in the first direction I and the second direction II by the gantry moving unit 300 and the head moving unit 500 to move the liquid crystal discharge amount measuring unit 800 As shown in FIG. The head moving unit 500 moves the inkjet head units 400a, 400b and 400c in the third direction III to move the inkjet head units 400a, 400b and 400c and the liquid crystal discharge volume measuring unit 800 in the vertical direction Can be adjusted.

 The nozzle inspection unit 900 confirms whether or not the individual nozzles provided to the inkjet head units 400a, 400b and 400c are abnormal through the optical inspection. When the abnormality of the macroscopic nozzle is checked by the liquid crystal discharge quantity measurement unit 800 and it is judged that there is an abnormality in the unspecified nozzle, the nozzle inspection unit 900 checks the existence of abnormality of the individual nozzle, .

The nozzle inspection unit 900 may be disposed on one side of the substrate supporting unit 100 on the base B. [ The inkjet head units 400a, 400b and 400c are moved in the first direction I and the second direction II by the gantry moving unit 300 and the head moving unit 500, Lt; / RTI > The head moving unit 500 can move the heads 410, 420 and 430 in the third direction III to adjust the vertical distance between the inkjet head units 400a, 400b and 400c and the nozzle inspection unit 900. [

The head cleaning unit 1000 performs a purging process and a suction process. The purging process is a process in which a part of the liquid crystal accommodated in the inkjet head units 400a, 400b and 400c is injected at a high pressure. The suction process is a process of sucking and removing residual liquid crystal on the nozzle surface of the inkjet head units 400a, 400b, and 400c after the purging process.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

B: Base 100: Substrate supporting unit
200: Gantry 300: Gantry moving unit
400: inkjet head unit 412: body
420: Lever 430: Sensor
440: Head 460: Pressure control unit
461: pressure controller 463: pneumatic line
465: Buffer box 467: Reverse flow sensor
471: Pressure control valve 473: Valve control part
500: inkjet mobile unit 600: liquid crystal supply unit
672: liquid crystal source 674:
675: liquid crystal supply line

Claims (16)

A head having nozzles for ejecting a chemical liquid onto a substrate by an inkjet method;
Wherein a reservoir space for storing a chemical solution is formed inside the reservoir, and a reservoir for supplying a chemical solution to the head; And
And a pressure control unit for controlling the pressure of the reservoir space,
The pressure control unit
Pressure controller;
A pneumatic line connecting the pressure controller and the reservoir; And
And a buffer box provided on the pneumatic line and having a buffer space having a cross-sectional area larger than that of the passage in the pneumatic line. The method according to claim 1,
Wherein the buffer space has a larger volume per unit length than the flow path of the pneumatic line. The method according to claim 1,
The pressure control unit
A backflow sensor for detecting the backflow of the chemical liquid to the pressure controller;
A pressure control valve installed in the pneumatic line in a section between the pressure controller and the buffer box; And
And a valve control unit for controlling the pressure control valve so that the chemical liquid does not flow to the pressure controller when the backflow sensor senses backflow of the chemical liquid. The method of claim 3,
Wherein the backflow monitoring sensor senses backflow of the chemical solution through the buffer space. The method of claim 3,
Wherein the valve control unit closes the pressure regulating valve to shut off the flow path of the pneumatic line when the backflow of the chemical liquid is sensed. The method of claim 3,
Wherein the pressure control valve is a three-way valve,
The pressure control unit
And a bypass line connected to the pressure control valve and branched from the flow path of the pneumatic line,
Wherein the valve control unit controls the pressure control valve so that the flow of the chemical liquid is shut off to the pressure controller when the backflow of the chemical liquid is detected and the chemical liquid is discharged to the bypass line side. The method of claim 3,
The pressure control unit
Further comprising a bypass line connected to the buffer box and having a discharge valve,
Wherein the valve control unit opens the discharge valve when the backflow of the chemical liquid is sensed. The method of claim 3,
The pressure control unit
And a filter installed in the pneumatic line in a section between the pressure controller and the pressure control valve. The method according to claim 1,
Wherein the buffer box is provided at a front end of the pneumatic line adjacent to the reservoir. The method according to claim 1,
Wherein the buffer box is provided at a rear end of the pneumatic line adjacent to the pressure controller. A substrate supporting unit on which a substrate is placed;
A gantry provided on a moving path of the substrate supporting unit and movable in one direction;
A plurality of heads mounted on the gantry and having nozzles for ejecting a chemical liquid onto the substrate by an inkjet method;
Wherein a reservoir space for storing a chemical solution is formed inside the reservoir, and a reservoir for supplying a chemical solution to the head; And
And a pressure control unit for maintaining the reservoir space at a negative pressure,
The pressure control unit
Pressure controller;
A pneumatic line connecting the pressure controller and the reservoir; And
And a buffer box provided on the pneumatic line and having a buffer space having a larger volume per unit length than the flow path in the pneumatic line. 12. The method of claim 11,
The pressure control unit
A backflow sensor for detecting the backflow of the chemical liquid to the pressure controller through the buffer space;
A pressure control valve installed in the pneumatic line in a section between the pressure controller and the buffer box; And
And a valve control unit for adjusting the pressure control valve so that the chemical solution does not flow to the pressure controller when the backflow sensor detects the backflow of the chemical solution. 13. The method of claim 12,
Wherein the pressure control valve is a three-way valve,
The pressure control unit
And a bypass line connected to the pressure control valve and branched from the flow path of the pneumatic line,
Wherein the valve control unit controls the pressure control valve so that the flow of the chemical liquid is blocked to the pressure controller side and the chemical liquid is discharged to the bypass line side when the backflow of the chemical liquid is detected. 13. The method of claim 12,
The pressure control unit
Further comprising a bypass line connected to the buffer box and having a discharge valve,
Wherein the valve control unit opens the discharge valve when the backflow of the chemical liquid is sensed. 12. The method of claim 11,
Wherein the buffer box is provided at a front end of the pneumatic line adjacent to the reservoir. 12. The method of claim 11,
Wherein the buffer box is provided at a rear end of the pneumatic line adjacent to the pressure controller.

Images