Device and method for fabricating display panel having ink-jet printing applied thereto

Device and method for fabricating a display panel having ink-jet printing applied thereto, the device including a stage for supporting a substrate, a base having one or more than one rail for transporting the stage, and one or more than one ink-jet head rotatable by an angel for spraying a pattern forming solution to the substrate, thereby reducing a fabrication cost and simplifying a fabrication process.

This application claims the benefit of the Korean Application No. P2002-18968 filed on Apr. 8, 2002, which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to device and method for fabricating a display panel, more particularly, to device and method for fabricating a display panel having ink-jet printing applied thereto for reducing a production cost and simplifying a fabrication process of a panel.

2. Background of the Related Art

In general, cathode-ray tubes (CRT) have been used mostly as displays. However, following digitization of information, a new concept of displays is required. For an example, compact displays with low power consumption are required in an environment requiring mobility, such as cars, or airplanes, or portable computers, and large sized displays with high luminance, and width angle of view are required in an environment in which delivery of information to the mass of people is required.

Recently, researches and development for flat panel displays (FPD) are in progress actively as displays suitable for a variety of environments as explained above. As the flat panel displays, there are liquid crystal display (LCD), plasma display panels (PDP), field emitter displays (FED), and electroluminescent displays (ELD).

However, for putting the displays into practical use, it is required that the fabrication processes of the displays are simplified for dropping a fabrication cost. Particularly, cost reduction of the panel pattern fabrication process which requires expensive equipment and complicate fabrication steps is very keen.

In a related art patterning, photolithography and screen printing are used mostly. Though thin and even pattern is available, the photolithography has a high material cost, and complicated fabrication process, as many fabrication steps, such as deposition, masking, etching, and the like, are required. Though the fabrication process is simple, and fabrication equipment is not expensive compared to the photolithography, the thin and even pattern is available from the screen print.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to device and method for fabricating a display panel having ink-jet printing applied thereto that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide device and method for fabricating a display panel having ink-jet printing applied thereto, which can reduce fabrication cost and simplify process steps.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the device for fabricating a display panel having ink-jet printing applied thereto includes a stage for supporting a substrate, a base having one or more than one rail for transporting the stage, and one or more than one ink-jet head rotatable by an angel for spraying a pattern forming solution to the substrate.

The angle of rotation of the ink-jet head are controlled by head controlling means according to intervals of patterns intended to form.

The head control means includes head holders each for holding the ink-jet heads, and two support plates for supporting the head holders.

The head control means includes head holders each for holding the ink-jet heads, and gears each connected to a center shaft of one of the head holders and engaged with each other for rotating the head holders.

The device for fabricating a display panel having ink-jet printing applied thereto further includes cleaning means for cleaning and capping the ink-jet heads, a plurality of CCD cameras and monitors for monitoring positions of the substrate and the ink-jet heads and spraying action (state) of the ink-jet heads, and a head support having rails for transporting the ink-jet heads.

In another aspect of the present invention, there is provided a device for fabricating a display panel having ink-jet printing applied thereto including a stage for supporting a substrate, a base having one or more than one rail for transporting the stage, and ink-jet heads each having a plurality of nozzles for spraying a pattern forming solution to the substrate, head controlling means for turning the ink-jet heads by a preset angle according to intervals of patterns intended to form, cleaning means for cleaning the ink-jet heads, and one or more than one camera for monitoring the substrate and the nozzles.

The stage includes an upper plate, a lower plate, and rails between the upper and lower plate running perpendicular to rails on the base.

The head controlling means turns the ink-jet heads by a preset angle with reference to a direction perpendicular to a length direction of the patterns intended to form, and the head controlling means turns the ink-jet heads the greater as the intervals between the patterns the smaller.

The head controlling means includes head holders for holding the ink-jet heads, two support plates for supporting the head holders.

The head control means includes head holders each for holding the ink-jet heads, and gears each connected to a center shaft of one of the head holders and engaged with each other for rotating the head holders.

The ink-jet head is movable in up/down directions.

The cleaning means is movable along the rails on the base for capping the nozzles when the ink-jet heads are not in use.

In further aspect of the present invention, there is provided a method for fabricating a display panel having an ink-jet printing applied thereto, including the steps of setting ink-jet heads with the ink-jet heads turned by a preset angle with reference to a direction perpendicular to a length direction of the patterns according to intervals of patterns intended to form, monitoring positions of the nozzles of the ink-jet heads, aligning a substrate on a stage, and spraying a pattern forming solution onto the substrate through nozzles in the ink-jet heads while moving the substrate.

The setting step includes the step of setting a number of the ink-jet heads according to a number of the patterns intended to form, and the setting step includes the step of setting the angle the greater as the intervals between the patterns intended to form are the smaller.

The step of monitoring includes the step of CCD cameras monitoring positions of a first nozzle and a last nozzle of each of the ink-jet heads.

The method for fabricating a display panel having an ink-jet printing applied thereto further includes the step of cleaning the nozzles after the step of setting, the step of patterning a dummy for testing nozzles before the step of spraying, and the step of heat treatment for hardening the pattern forming solution after the step of spraying.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.FIG. 1illustrates a side view of a device for fabricating a display panel having ink-jet printing applied thereto in accordance with a preferred embodiment of the present invention.

Referring toFIG. 1, the device for fabricating a display panel having ink-jet printing applied thereto includes a stage2for supporting a substrate3, a base1having one or more than one rail4afor transporting the stage2, one or more than one ink-jet heads7each rotatable and movable in up/down direction and having a plurality of nozzles for spraying solution for forming a pattern on the substrate3, head control means200for controlling a rotation angle of the ink-jet head7according to an interval of patterns intended to form, and cleaning means6for wiping and capping the nozzles.

The substrate3may be a plastic substrate having a coat of ITO (Indium Tin Oxide), and the solution of forming the pattern may be one of solutions for forming patterns of a display panel, such as a color filter layer, an alignment film, fluorescent material, electrodes, dielectric layer, and the like.

The stage2includes an upper plate2a, and a lower plate2b, and rails4brunning perpendicular to rails4aon the base1between the upper and lower plates2aand2b. Since the rails4aand4bare running in perpendicular to each other, the upper plate2acan be moved in left/right directions one the rails4aand4b. Therefore, the substrate3and the ink-jet heads7can be aligned, accurately.

The ink-jet head7is movable along a rail4cattached to a head support5during patterning, as well as in up/down directions for adjusting a gap between the ink-jet head7and the substrate3according to the up/down movement of the head support5. 1˜100 ink-jet heads may be fitted according to the pattern the user intends to form, and the pattern can be formed by one flow of process.

FIG. 2illustrates head control means in a device for fabricating a display panel -having ink-jet printing applied thereto in accordance with a first preferred embodiment of the present invention, andFIG. 3illustrates head control means in a device for fabricating a display panel having ink-jet printing applied thereto in accordance with a second preferred embodiment of the present invention.

Referring toFIG. 2, the first embodiment head control means200includes head holders21each for holding an ink-jet head7, and two support plates22each connected to a shaft23of the head holder21for supporting the head holder21. When the two support plates22move in opposite directions, the ink-jet heads7turn at an angle with reference to a direction perpendicular to a length direction of the pattern intended to form.

Also, referring toFIG. 3, the second embodiment head control means200includes head holders31each for holding an ink-jet head7, gears34engaged with each other each connected to a central shaft33of the head holder31for turning the head holders31, and a support plate32between the head holders31and the gears34.

The first, or second embodiment head control means200can turn the ink-jet heads7at the same angle.

Also, referring toFIGS. 7,8, and9, a device for fabricating a display panel having an ink-jet printing applied thereto of the present invention may further includes CCD cameras71a, and71band monitors72aand72bfor monitoring positions of the nozzles at the ink-jet heads7, CCD cameras81a, and81band monitors82a, and82bfor monitoring a position of the substrate3, and a CCD camera91cand monitor (not shown) for monitoring a spray state the nozzles of the ink-jet head7spraya pattern solution.

A method for fabricating a pattern of a display panel by using the foregoing device for fabricating a display panel having an ink-jet printing applied thereto will be explained.FIG. 4illustrates a flow chart showing the step of a method for fabricating a pattern of a display panel having ink-jet printing applied thereto in accordance with a preferred embodiment of the present invention.

At first, a plurality of ink-jet heads7are set, and a solution for forming a pattern is loaded on ink-jet heads7from a tube (not shown) for storing the solution (S1). 1˜100 ink-jet heads7may be fitted according to a number of patterns51to be formed. For an example, if it is intended to form 320 patterns51by using ink-jet heads7each having 32 nozzles by one pass of flow, 10 ink-jet heads7are required.

Referring toFIG. 5, the ink-jet heads7are turned by a required angle θ according to intervals of the patterns51intended to form, such that the ink-jet heads7are arranged oblique with reference to a direction V perpendicular to a length direction of the patterns51. The ink-jet heads7are arranged oblique for bringing the nozzles52to positions of the patterns51, when intervals ‘A’ of the nozzles52are greater than intervals ‘B’ of the patterns51.

The oblique angle θ of the ink-jet heads7with reference to the direction ‘V’ perpendicular to a length direction of the patterns51intended to form is varied with the intervals ‘B’ of the patterns, i.e., a resolution of the display.

For an example, referring toFIG. 6, a color filter layer of a PDP, or LCD has R, G, B patterns61a,61b,61crepeatedly arranged at fixed intervals. In a case of 40″ display with a VGA (Video Graphics Array) class resolution, the intervals ‘Y’ between the same color patterns are approx. 1.2 μm. Therefore, as intervals ‘X’ of the nozzles62of the ink-jet heads67a,67b,67cfor spraying three kinds of solutions for forming the R, G, B patterns61a,61b,61care approx. 1.4 μm, for bringing the nozzles62to relevant positions of the patterns, it is required that the ink-jet heads67a,67b,67care arranged oblique by approx. 32° with reference to a direction perpendicular to a length direction of the R, G, B patterns61a,61b,61c.

In a case of a display with a WXGA class resolution of a resolution higher than the display with a VGA class resolution, for bringing the nozzles62to relevant positions of the patterns, it is required that the ink-jet heads67a,67b,67care arranged oblique by approx. 62° with reference to a direction perpendicular to a length direction of the R, G, B patterns61a,61b,61c. This is because the intervals of R, G, B patterns of the WXGA class are smaller than the intervals of the R, G, B patterns of the VGA class. That is, the higher the resolution of a display, the greater the oblique angle of the ink-jet heads67a,67b, and67c.

Then, nozzles of the ink-jet heads7are cleaned S2, by bringing the cleaning means6under the ink-jet heads7along the rail, and wiping nozzle surfaces, for removing foreign matters stuck to the nozzles and improving meniscus of the nozzles52.

In the cleaning, if the cleaning means6does not move, and, instead, the ink-jet heads7move, defective spraying of the ink-jet heads7may be caused by washing of the pattern forming solution in the ink-jet heads7. Therefore, it is preferably that the cleaning means6is brought under the ink-jet head7.

Then, referring toFIG. 7, when the cleaning process is finished, position accuracy of the nozzles52of the ink-jet heads7are monitored by using CCD cameras71aand71band monitors72aand72b(S3). If the positions of the nozzles52are not accurate, the nozzles52are re-arranged. Since the CCD camera71aand71bare movable along the rails4aand4bin left/right directions, the nozzles52can be monitored in succession. In order to reduce a fabrication time period, the CCD cameras71aand71bmay monitor positions of a first and last nozzles of each of the ink-jet heads7. Moreover, since the ink-jet heads7are movable in up/down directions, a distance between the nozzles52and the substrate3may be adjusted.

Then, referring toFIG. 8, after arranging positions of the nozzles52accurately, the substrate3is placed on an upper plate2a, an X-Y stage (S4), the substrate3is brought to a set position on the upper plate2a(S5). In this instance, positions of marks83on the substrate3of being at the set positions on the upper plate2aare verified by using the CCD cameras81aand81band the monitors82aand82b.

Then, referring toFIG. 9, for testing whole nozzles52of the ink-jet heads7, dummy pattern is formed, because most of abnormal signs occur, not while the nozzles52spray the pattern forming solution, but when the nozzles52start to spray the pattern forming solution. The foreign matters at the entrance of the nozzles32may be removed by the dummy patterning.

Then, the nozzles52spray pattern forming solution onto the substrate3while the substrate3is moved along the rail4aby the stage2(S6). In this instance, it is required that a viscosity of the pattern forming solution is adjusted taking step coverage of the patterns intended to form into account. That is, when it is intended to form a pattern having a good step coverage, the viscosity of the pattern forming solution is increased, and vice versa. Thus, the device for fabricating a display panel having an ink-jet printing applied thereto of the present invention can improve a pattern step coverage and can form uniform patterns.

Referring toFIG. 10, a state in which the nozzles52spray the pattern forming solution is monitored in real time by using the CCD camera94. The CCD camera94is also movable in left/right directions along the rail4c, and4f.

Referring toFIG. 11, after formation of the patter51is finished, the substrate3is inspected (S7). Then, the process proceeds to the next process, i.e., if it is assumed that it is a process for forming the R, G, B filter, for carrying out heat treatment for hardening the pattern forming solution sprayed onto the substrate3, the substrate3are moved to a baking oven along a rail in line (S8).

As has been explained, the device and method for fabricating a display panel having ink-jet printing applied thereto of the present invention have the following advantages.

By turning the ink-jet heads by an angle according to intervals of patterns, display panels with different resolutions can be fabricated. Therefore, a fabrication cost can be saved.

The once through formation of the pattern by spraying the pattern forming solution, a fabrication time period can be reduced, and fabrication process can be simplified.

The spray of solution for forming a pattern permits to improve step coverage, to form uniform patterns.

The present invention is applicable, not only to the color filter process of a display panel, but to all processes, such as fluorescent material coating, formation of electrode and spacer, and the like.