US20060068083A1

US20060068083A1 - Device and method for fabricating display panel having ink-jet printing applied thereto

Info

Publication number: US20060068083A1
Application number: US11/260,173
Authority: US
Inventors: Eun Moon; Bum Bae; Young Cho; Ji Sohn; Byung Ryu
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2002-04-08
Filing date: 2005-10-28
Publication date: 2006-03-30
Also published as: US20040252153A1; KR20030080380A; KR100437799B1; US20030189606A1; US6997536B2; JP4012109B2; JP2003303544A; US6799826B2

Abstract

A device and method for fabricating a display panel having ink-jet printing applied thereto is disclosed, in which it is possible to simplify fabricating process steps and to reduce production cost, and to prevent pattern failure. The device includes a stag having a hole and supporting a substrate; one or more ink-jet heads having nozzles spraying pattern forming solution onto the substrate; and one or more cameras positioned below the stage so as to monitor the nozzles through the holes.

Description

This application is a divisional of Ser. No. 10/406,218 filed Apr. 4, 2003, which claims the benefit of the Korean Application No. P2002-13970 filed on Apr. 8, 2002, both are hereby incorporated bar 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 preventing a pattern failure.
2. Background of the Related Art
In general, cathode-ray tubes (CRT) have been mostly used as information displays. However, with digitization of information, a new concept of display is required by environmental changes. For example, compact displays obtaining thinness and lightness with low power consumption are required in an environment requiring mobility, such as cars, or airplanes, or portable computers. Meanwhile, large sized displays with high luminance and wide viewing angle 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 actively performed in that the FPDs are suitable for a variety of environments as explained above. There are the flat panel displays such as liquid crystal display (LCD), plasma display panels (PDP), field emitting displays (FED), and electroluminescent displays (ELD).
For commercialization of the displays, it is required to simplify fabricating process steps, thereby decreasing production cost. Especially, it is important to reduce cost in a panel patterning process since the panel patterning process requires expensive equipment and complicated fabricating process steps.
In a related art patterning process, photolithograph and screen-printing method are mostly used. In this related art process, though thin and even pattern is available, the photolithography has a high material cost, and complicated fabricating process steps such as deposition, masking, etching, and the like, are required. The screen-printing method has simple fabricating process steps, and fabricating equipment used in the screen-printing method is not expensive as compared to the photolithography, however, it is hard to obtain thin and even pattern in the screen-printing method.

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, in which it is possible to simplify fabricating process steps and to reduce production cost.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice or the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a device for fabricating a display panel having ink-jet printing applied thereto includes a stage including a hole and supporting a substrate; one or more ink-jet heads having nozzles spraying pattern forming solution onto the substrate; and one or more cameras positioned below the stage so as to monitor the nozzles through the holes.
Preferably, the holes of the stage are aligned to be correspondent with align marks of the substrate.
Preferably, the device further includes a head control means for controlling a rotation angle of the ink-jet heads according to intervals between the patterns, and the head control means turns the ink-jet headers at a great angle with reference to a direction perpendicular to a length direction of the patterns as the interval between the patterns becomes smaller.
Preferably, the device further includes one or more monitors monitoring the nozzles with grids having a predetermined distance according to the interval between the patterns intended to form.
In another aspect of the present invention, a device for fabricating a display panel having ink-jet printing applied thereto includes a stage supporting a substrate having align marks, and having holes for being corresponding to the align marks; a plurality of rotary ink-jet heads having nozzles spraying pattern forming solution onto the substrate; cameras being fitted below each hole of the stage for monitoring the nozzles through the holes; and monitors being connected with the cameras so as to monitor the nozzles with grids having a fixed interval according to an interval between the patterns intended to form.
In another aspect of the present invention, a method for fabricating a display panel having ink-jet printing applied thereto includes the steps or (a) setting ink-jet heads; (b) monitoring positions of the nozzles of the ink-jet heads by monitoring grids having the fixed interval according to the interval of the patterns; (c) arranging the substrate on the stage; and (d) spraying pattern forming solution into the substrate through the nozzles of the ink-jet heads in a state of moving the substrate.
Preferably, the ink-jet heads are set to be turned at a predetermined angle according to the interval between the patterns intended to form, and the ink-jet heads are turned at a great angle with reference to a direction perpendicular to a length direction of the patterns as the interval of the patterns becomes smaller.
Preferably, the holes of the stage are aligned to be correspondent with the align marks of the substrate.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and, constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. In the drawings:
FIG. 1 illustrates a (representative) view of a device for fabricating a displays panel having ink-jet printing applied thereto in accordance with a preferred embodiment of the present invention;
FIG. 2 illustrates a plan view of a stage and a substrate in FIG. 1;
FIG. 3 illustrates an arrangement view of ink-jet heads in a device for fabricating a display panel having ink-jet printing applied thereto in accordance with one preferred embodiment of the present invention;
FIG. 4 illustrates an arrangement view of ink-jet heads in a device for fabricating a display panel having ink-jet printing applied thereto in accordance with another preferred embodiment of the present invention;
FIG. 5 illustrates a flow chart showing the steps of a method for fabricating a display panel having ink-jet printing applied thereto in accordance with the preferred embodiment of the present invention; and
FIG. 6A to FIG. 6C illustrate views showing the steps of a method for fabricating a display panel having ink-jet applied thereto in accordance with the preferred embodiment of the present invention.

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. 1 illustrates a (representative) 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. FIG. 2 illustrates a plan view of a stage and a substrate in FIG. 1.
Referring to FIG. 1 and FIG. 2, a device for fabricating a display panel having ink-jet applied thereto in accordance with a preferred embodiment of the present invention includes a stage 2, a plurality of ink-jet heads 7, and one or more CCD cameras 4. The stage 2 including one or more holes supports a substrate 1, and each ink-jet head 7 has a nozzle 52 spraying pattern forming solution onto the substrate 1. Also, each CCD camera 4 is fixed below each hole 3 for monitoring positions of the nozzles 52 through the holes 3 of the stage 2.
At this time, the substrate 1 may be a transparent glass substrate or a plastic substrate coated with indium tin oxide (ITO) according to the kind of the display. The pattern forming solution may be one of solutions for forming patterns of the display panel, such as a color filter layer an alignment film, fluorescent material, electrodes, dielectric layer, and the like. The holes 3 of the stage 2 are arranged for being aligned with align marks 5 of the substrate 1. Furthermore, rails 8 are arranged on a base 6 below the stage 2 for moving the stage 2 in left/right directions. On the ink-jet heads 7, a head support means 10 is arranged so as to support the ink-jet heads 7, and a head control means 9 is arranged for rotating the ink-jet heads 7.
As shown in FIG. 3 and FIG. 4, the head control means 9 rotates the ink-set head 7 at a predetermined angle according to an interval between the patterns being intended to form on the substrate 1. The head support means 10 can move the ink-jet heads 7 in up/down directions for adjusting an interval between the ink-jet heads 7 and the substrate 1. Also, the ink-jet heads may be formed at 1 to 100 according to the pattern that the user intends to form, and the pattern can be formed by one flow of process. In order to accurately determine the positions of the nozzles 52, monitors for showing grids 12 at a predetermined distance according to a pitch B between the patterns 51 for being intended to print are respectively connected to the CCD cameras 4.
A method for fabricating the patterns of the display panel having the ink-jet applied thereto in accordance with the preferred embodiment of the present invention will be explained as follows. FIG. 5 illustrates a flow chart showing the steps of a method for fabricating a display panel having ink-jet printing applied thereto in accordance with the preferred embodiment of the present invention. FIG. 6A to FIG. 6C illustrate views showing the steps of a method for fabricating a display panel having ink-jet applied thereto in accordance with the preferred embodiment of the present invention.
As shown in FIG. 6A, the plurality of ink-jet heads 7 are set on the head support means 10 (S1), and the pattern forming solution is loaded to the ink-jet head 7 from a tube (not shown) storing the pattern forming solution. At this time, the ink-jet heads 7 of 1 to 100 may be provided, and the number of the ink-jet head 7 to be set corresponds with the number of the patterns 51 intended to form. For example, if it is intended to form 320 patterns 51 with the ink-jet head 7 having 32 nozzles by one flow of process, 10 ink-jet heads 7 have to be set.
Referring to FIG. 3, the ink-jet heads 7 are rotated at a predetermined angle θ by the head control means 200 according to the interval B between the patterns 51 intended to form, so that the ink-jet heads 7 are arranged to be oblique to a direction V perpendicular to a length direction of the patterns 51. Accordingly, even though an interval A between the nozzles 52 is wider than the interval B between the patterns 51, each nozzle 52 is positioned to be correspondent with each pattern 51.
The oblique angle θ of the ink-jet heads 7 with reference to the direction V perpendicular to the length direction of the patterns 51 is varied with the interval B between the patterns 51, resolution or the display. For example, as shown in FIG. 4, the color filter layers of PDP and LCD are composed of R, G and B patterns 61 a, 61 b, 61 c being repeatedly arranged at fixed intervals. Meanwhile, in a case of 40-inch display with a VGA (Video Graphics Array) class resolution, the intervals ‘Y’ between the same color patterns are approx. 1.2 μm. As intervals ‘X’ of the nozzles 52 of the ink-jet heads 67 a, 67 b, 67 c for spraying three kinds of solutions for forming the R, G, B patterns 61 a, 61 b, 61 c are approx. 1.4 μm, for arranging the nozzles 62 to corresponding positions of the patterns, it is required that the ink-jet heads 67 a, 67 b, 67 c are arranged oblique by approx. 32° with reference to a direction perpendicular to a length direction of the R, G, B patterns 61 a, 61 b, 61 c.
In a case of a display with a WXGA class resolution of a resolution higher than the display with a VGA class resolution, for arranging the nozzles 62 to corresponding positions of the patterns, it is required that the ink-jet heads 67 a, 67 b, 67 c are arranged for being oblique by approx. 62° with reference to a direct on perpendicular to the length direction of the R, G, B patterns 61 a, 61 b, 61 c. This is because the intervals of R, C, B patterns of the WXGA class are smaller than the intervals or 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 heads 67 a, 67 b, and 67 c.
Referring to FIG. 6B, position accuracy of the nozzles 52 of the ink-jet heads 7 is monitored with CCD cameras 4 and monitors 11 (S2). The CCD cameras 4 move with the stage 2 so as to sequentially monitor the ink-jet heads 7 through the holes 3 of the stage 2. At this time, the nozzles 52 being monitored have to be correspondent with the grids 12 of the monitor. If the positions of the nozzles 52 are not accurately correspondent with the grids 12, the nozzles 52 are correspondent with the grids 12 by rearranging the ink-jet heads 7.
Referring to FIG. 6C, after arranging positions of the nozzles 52 accurately, the substrate 1 is placed on the stage 2 (S4), and then the substrate 1 is set to a predetermined portion of the stage 2 (S5). At this time, it has to be checked whether align marks 5 of the substrate 1 are accurately aligned with each hole 3 of the stage 2 by the CCD cameras 4 and the monitors 11. In order to more accurately align the substrate 1, each align mark 5 has to be aligned for being correspondent with each nozzle 52 on the hole 3.
After that, for testing whole nozzles 52 of the ink-jet heads 7, a dummy patterning process is performed since most of abnormal signs occur, not while the nozzles 52 spray the pattern forming solution, but when the nozzles 52 start to spray the pattern forming solution. Also, the foreign matters at the entrance of the nozzles 52 made be removed by the dummy patterning.
Then, the nozzles 52 spray pattern forming solution onto the substrate 3 while the substrate 3 is moved along the rail 8 by the stage 2 (S6). Zn this instance, it is required that a viscosity of the pattern forming solution is adjusted in consideration characteristics of step coverage of the patterns intended to form. That is, when it is intended to form a pattern having good step coverage, the viscosity of the pattern forming solution is increased. In opposite case, the viscosity of the pattern forming solution is decreased. Accordingly, the device for fabricating a display panel having an ink-jet printing applied thereto according to the present invention can improve step coverage characteristics of the patterns, and can form uniform patterns.
After completing the pattern forming process, the substrate 1 is inspected (S7). Subsequently, the next process, i.e., if it assumed that it is a process for forming the R, G, B color filter, is performed for carrying out heat treatment for hardening the pattern forming solution sprayed onto the substrate 1, and then the substrate 1 is moved to a baking oven along the rail (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 the predetermined angle according to the interval between patterns, display panels having various resolutions can be fabricated, thereby decreasing a production cost.
Also, it is possible to prevent failure from generating due to a mismatching between the interval of the patterns and the interval of the nozzles.
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.
It will be apparent to those skilled in the art that various modifications and variations can be made in the device and method for fabricating a display panel having ink-jet printing applied thereto of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they, come within the scope of the appended claims and their equivalents.

Claims

1-7. (canceled)

8. A method of fabricating a display panel, comprising:

setting one or more ink-jet heads on a head supporting device;

rotating the one or more ink-jet heads with respect to the head supporting device to a predetermined angle corresponding to an interval between patterns intended to be formed onto a substrate; and

spraying patterns forming solution onto the substrate through one or more nozzles of the one or more ink-jet heads.

9. The method as claimed in claim 8, wherein rotating the one or more ink-jet heads with respect to the head supporting device comprises rotating the one or more ink-jet heads with respect to the head supporting device to a greater angle with respect to a length direction of the patterns as the interval between patterns decreases.

10. The method as claimed in claim 8, wherein a number of ink-jet heads corresponds to a number of patterns intended to be formed on the substrate.

11. The method as claimed in claim 8, wherein the pattern forming solution comprises a solution for forming a pattern corresponding to one of a color filter layer, an alignment film, fluorescent material, electrodes, or a dielectric layer.

12. The method as claimed in claim 8, wherein the substrate comprises one of a transparent glass substrate or a plastic substrate coated with indium tin oxide.

13. The method as claimed in claim 8, further comprising:

arranging the substrate on a stage.

14. The method as claimed in claim 13, further comprising:

moving the stage and thus the substrate during the spraying step.

15. The method as claimed in claim 13, further comprising:

aligning one or more marks provided on the substrate with one or more holes provided on the stage.

16. The method as claimed in claim 13, further comprising monitoring the one or more nozzles of the one or more ink-jet heads through one or more holes provided on the stage using one or more imaging devices.

17. The method as claimed in claim 8, further comprising:

monitoring positions of the one or more nozzles of the one or more ink-jet heads by monitoring grids having a predetermined interval corresponding to the interval between patterns intended to be formed onto the substrate.

18. The method as claimed in claim 8, further comprising:

performing a dummy patterning process for testing the one or more nozzles of the one or more ink-jet heads before spraying the pattern forming solution onto the substrate.

19. The method as claimed in claim 8, further comprising performing a heat treatment process for hardening the pattern forming solution after spraying the pattern forming solution onto the substrate.

20. Apparatus for fabricating a display panel, comprising:

a head supporting device;

one or more ink-jet heads configured to be supported by the head supporting device and each having one or more nozzles configured to spray pattern forming solution onto a substrate; and

a head control device interposed between each of the one or more ink-jet heads and the head support device and configured to rotate the respective ink-jet head with respect to the head supporting device.

21. The apparatus as claimed in claim 20, wherein the head control device rotates the respective ink-jet head to a predetermined angle corresponding to an interval between patterns intended to be formed onto a substrate.

22. The apparatus as claimed in claim 21, wherein the head control device rotates the respective ink-jet head to a greater angle with respect to a length direction of the patterns as the interval between patterns decreases.

23. The apparatus as claimed in claim 20, wherein the head supporting device is configured to move in an up/down direction to control a distance between the one or more ink-jet heads and a substrate.

24. The apparatus as claimed in claim 20, further comprising a stage for supporting a substrate.

25. The apparatus as claimed in claim 24, wherein the stage is configured to be movable in a left/right direction.

26. The apparatus as claimed in claim 24, wherein the stage comprises one or more holes.

27. The apparatus as claimed in claim 26, wherein the one or more holes are configured to be aligned with align marks on a substrate.

28. The apparatus as claimed in claim 26, further comprising one or more imaging devices configured to monitor the one or more nozzles through the one or more holes.

29. The apparatus as claimed in claim 28, wherein the one or more imaging devices comprise one or more cameras.

30. The apparatus as claimed in claim 28, further comprising one or more display devices in communication with the one or more imaging devices.

31. The apparatus as claimed in claim 20, wherein the pattern forming solution comprises a solution for forming a pattern corresponding to one of a color filter layer, an alignment film, fluorescent material, electrodes, or a dielectric layer.

32. The apparatus as claimed in claim 20, wherein a number of ink-jet heads corresponds to a number of patterns intended to be formed on a substrate.