KR20100088768A - Apparatus and method for printing of a flat panel display - Google Patents

Abstract

PURPOSE: A printing apparatus and a printing method for a flat panel display are provided to improve the printing uniformity by printing a color paste on the flat display panel using a paste board and a gas spraying unit. CONSTITUTION: A paste board(24) is arranged on the upper side of a flat display panel(21). A plurality of through holes for a paste(23) is formed in the paste board, and a color paste(27) fills the through holes. The through holes match the pixel pattern of the flat display panel. A gas spraying unit(26) is arranged on the upper side of the paste board and sprays gas through the through holes. The color paste is transferred to the flat display panel.

Description

Printing apparatus and method of flat panel display {Apparatus and method for printing of a flat panel display}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for manufacturing flat panel displays, and more particularly, to an apparatus and method for printing a pattern such as a fluorescent layer, a color filter layer, and an organic light emitting layer (OLED layer) on a substrate of a flat panel display.

Typical flat panel displays include a plasma display device (PDP), a liquid crystal display (LCD), an organic light emitting diode (OLED), and the like. Each flat panel display should have a pattern such as a fluorescent layer, a color filter layer, and an organic light emitting layer (OLED layer) for displaying color.

FIG. 1 is a schematic diagram showing the structure of a general plasma display device (PDP) as one type of flat panel display. The plasma display device includes an upper substrate 130 having discharge electrodes formed therein and a lower substrate 110 having partition walls 120 formed thereon. The fluorescent layer 140 is formed on the surface of the partition wall 120 formed on the lower substrate 110. When the ultraviolet rays of the plasma generated between the discharge electrodes stimulate the fluorescent layer 140, visible light of red (R), green (G), and blue (B) is generated according to the type of the fluorescent layer 140 to display an image. do.

As another flat panel display, a liquid crystal display (LCD) displays an image by converting white light of a backlight into red (R), green (G), and blue (B) light while passing through a glass substrate on which a color filter layer is patterned. . In the organic light emitting diode (OLED), when voltage is applied to the cathode and the anode, electrons and holes injected through the cathode and the anode are recombined in the organic light emitting layer (OLED layer), and the excitation state generated at this time is in the bottom state ( Returning to the ground state, visible light of red (R), green (G), and blue (B) is generated depending on the type of the organic light emitting layer (OLED layer).

As such, the plasma display device (PDP) displays an image on a fluorescent layer, the liquid crystal display (LCD) displays an image on a color filter layer, and the organic light emitting diode (OLED) displays an image on an organic light emitting layer (OLED layer). .

Color material for displaying respective R, G, and B colors is printed on the fluorescent layer, the color filter layer, and the organic light emitting layer. As an example, the color material of the fluorescent layer is a phosphor paste, the color material of the color filter layer is an ink, and the color material of the organic light emitting layer is an organic light emitting polymer.

Recently, as the size and resolution of a display increases, the size of a pixel is smaller than 200 μm. Conventional methods of printing color materials to form fluorescent layers, color filter layers, organic light emitting layers, etc. of flat panel displays include screen printing, photolithography, evaporation, and inkjet methods ( inkjet) and LITI method (Laser Induced Thermal Imaging) using a laser.

The screen printing method has the advantages of simple and high productivity, as described in Korean Patent Application No. 1999-0009554 (name of the invention: plasma display panel and its phosphor coating method), but the mask is brought into contact with the substrate and the squeegee is applied. Since the paste is used to transfer the paste, color mixing tends to occur, and the amount of the paste to be applied is nonuniform and it is difficult to apply to a pixel of 200 μm or less.

The photolithography method is a method of exposing and developing using a photosensitive material, and is mainly used to form a color filter layer of a liquid crystal display (LCD) and an organic light emitting layer (OLED layer) of a polymer. This photolithography method has high dimensional accuracy, but since most materials are etched and removed by a developing process, a lot of expensive materials are lost and the process is complicated.

The deposition method is mainly used to form a low molecular weight organic light emitting layer (OLED layer), and described in Korean Patent Application No. 2007-0013776 (Invention name: Serial organic vaporization source for belt source deposition for the deposition process of organic devices) As described above, heat is applied to evaporate the organic material, and optionally, an organic light emitting layer is formed using a metal mask. The organic light emitting layer formed by this deposition method has the advantage of long life and high reliability because it is deposited in a vacuum state, but it is disadvantageous in that a lot of expensive materials are lost and it is difficult to obtain a uniform thin film of a large area.

The inkjet method has the advantage of low material loss and relatively fine patterns as described in the paper "Ink-Jet Printing of PLED Displays" (Information Display 2005, SID 2005). However, the phosphor powder or the organic matter contained in the paste can block the fine nozzle of the inkjet head, and the equipment is expensive because it must be sprayed while precisely controlling the position of the inkjet nozzle.

The LITI method using a laser is applied to a plastic film coated with a laser absorbing layer and a color layer such as a polymer in a solid state, as described in the research paper "Laser thermal patterning of OLED materials" (Proc. Of SPIE, Vol.5519, 2004). The color filter layer or the organic light emitting layer is printed by irradiating a laser while being in contact with the substrate. This LITI method has the advantage of high printing speed and high precision because it is heated by laser. However, there are disadvantages in that plastic film is difficult to manufacture, high quality laser is required, and material loss is large.

As described above, the conventional printing methods are all uneven in the amount of paste applied and are difficult to apply to high-definition displays, a lot of expensive materials are lost, a large area of uniform film is difficult to obtain, or the equipment is expensive. Production of plastic films is difficult, high quality lasers are required and material losses are large.

SUMMARY OF THE INVENTION An object of the present invention is to provide a device and method for uniformly and rapidly printing a fluorescent layer, a color filter layer, or an organic light emitting layer of a flat panel display.

According to an aspect of the present invention, there is provided a printing apparatus for a flat panel display, comprising: a paste substrate having a paste through hole disposed on an upper portion of the display substrate and filled with color material paste; And gas injection means for injecting gas into the paste through-holes so that the color material paste is transferred to the display substrate, and alignment means for aligning the display substrate and the paste substrate.

In addition, a printing method of a flat panel display according to the present invention includes a paste coating step of filling a color material paste into a paste through hole formed in a paste substrate, an alignment step of aligning the paste through hole on the display substrate, and a paste substrate. And a gas injection step of injecting a gas into the paste through hole onto the display substrate so that the color material paste is transferred to the display substrate.

According to the present invention, the fluorescent material and the color filter layer are filled by filling color pastes such as phosphor paste, ink or organic light emitting polymer into the through-holes processed in the paste substrate, and pushing the color material paste onto the display substrate using gas pressure. Another advantage is that the organic light emitting layer can be uniformly printed at high speed.

In addition, since only the required amount of color material paste is used, loss of color material paste can be minimized, and since it is a non-contact type, color mixing can be prevented during paste application.

In addition, since the paste substrate can be reused after being cleaned, the economical efficiency can be increased, and since the gas pressure is used, there is no limitation of the color material paste that can be applied.

In addition, if the paste substrate is made to be the same size as the display substrate and the paste through-hole of the same pattern as the display substrate is formed, the color material paste can be printed through one alignment, thereby minimizing the time required for the alignment of the substrate. Productivity can be improved.

Hereinafter, a printing apparatus and method of a flat panel display according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The present invention is equally applicable to printing all kinds of flat panel displays, namely, fluorescent layers of plasma display devices (PDPs), color filter layers of liquid crystal displays (LCDs), and organic light emitting layers of organic light emitting diodes (OLEDs). In addition, it can be easily applied to the existing printing process to print.

2 is a configuration diagram of a printing apparatus for a flat panel display according to a first embodiment of the present invention. FIG. 2A illustrates a state in which the printing apparatus is driven in the contact execution mode, and FIG. 2B illustrates a state in which the printing apparatus is driven in the droplet migration mode.

The printing apparatus 20 of the present invention includes a paste substrate 24 having a plurality of paste through holes 23 aligned with pixel positions between the partition walls 22 of the display substrate 21, and a plurality of paste through holes 23. The gas substrate 26 is provided with a plurality of gas through holes 25 that are aligned and aligned in a one-to-one correspondence, and the gas is supplied to the plurality of gas through holes 25 so that the paste passes through the gas through holes 25. And a gas supply means 28 for causing the color material paste 27 filled in the 23 to be transferred to the display substrate 21.

The operation of the configuration of the first embodiment of this invention will be described with reference to FIG. The color material paste 27 is filled in the plurality of paste through holes 23 formed in the paste substrate 24, and the plurality of paste through holes 23 of the paste substrate 24 and the plurality of gas through the gas substrate 26 are filled. The paste spraying positions of the holes 25 and the display substrate 21, that is, the pixels, are aligned.

When the gas supply means 28 injects gas into the upper portion of the gas substrate 26, gas is injected through a plurality of gas through holes 25 formed in the gas substrate 26, and the injected gas is pasted to the paste substrate 24. The pressure is applied to the upper portion of the color material paste 27 filled in the plurality of paste through holes 23 formed therein) to push the color material paste 27 downward. At this time, according to the magnitude of the gas pressure applied to the upper portion of the color material paste 27 or the shape of the paste through hole 23, the color material paste may be formed to form the paste through hole 23 as shown in FIG. As a result, it may be transferred to the display substrate 21, or may be transferred to the display substrate 21 in the form of a drop 29 as shown in FIG.

That is, when the gas pressure is less than a predetermined amount, as shown in FIG. 2A, the color material paste 27 extends along the paste through-hole 23 to the bottom of the partition 22 of the display substrate 21. The remaining color material paste is transferred to the display substrate 21 by the surface tension of the color material paste 27 in contact with the bottom of the partition wall 22 of the display substrate 21. As a result, a concave fluorescent layer to an organic light emitting layer is formed in the partition wall 22.

On the other hand, when the gas pressure is a certain amount or more, as shown in FIG. 2B, the color material paste is transferred to the display substrate 21 in the form of droplets 29. In the case where the shape of the paste through hole 23 is narrowed down, the color material paste can be transferred into the droplet form even at a lower gas pressure.

After the color material paste is transferred, the gas substrate is transferred in the X direction, and then gas is blown to transfer the color material paste filled in the other paste through holes. This is sequentially applied to all the paste through holes of the paste substrate to transfer the color material pastes of all the paste through holes to the display substrate.

In the embodiment of the present invention, one gas substrate is used to inject gas, but when the color material paste is injected using a plurality of gas substrates, the printing time may be shortened to improve productivity.

As described above, according to the magnitude of the gas pressure applied to the upper portion of the paste substrate, the color material paste flows down and is transferred by the surface tension or in the form of droplets. The transition by surface tension is possible only when the distance between the paste substrate and the display substrate of the printing apparatus is within the reference value. When the distance between the paste substrate and the display substrate of the printing apparatus is greater than the reference value, the transition to the droplet form must be performed. That is, the former is a method of shifting the color material paste in the contact transition mode, and the latter is a method of shifting the color material paste in the droplet migration mode.

The height of bulkheads varies according to the type of flat panel display. According to the height of the partition, the printing apparatus is driven in the contact transfer mode or the droplet transfer mode to the display substrate.

In the embodiment of the present invention, the contact transition mode means that the distance between the paste substrate of the printing apparatus and the bottom of the partition wall of the display substrate is shorter than the maximum expansion distance of the color material paste, so that the color material paste contacts the bottom of the partition wall and thus the surface tension. It means a drive mode that can be implemented by. When the height of the partition wall of the flat panel display is low, the printing apparatus may be driven in the contact execution mode.

If the height of the partition wall of the flat panel display is high, the printing apparatus cannot be driven in the contact execution mode. In this case, the printing apparatus causes the flow rate of the gas to be large or the shape of the paste through hole to be narrowed down so that the color material paste is transferred into the droplet form. In the present invention, such a driving mode is referred to as a droplet running mode.

The gas supply means of the present invention controls the pressure of the gas in accordance with the interval between the printing device and the bottom of the partition wall of the display substrate, if the interval is narrow, the gas flow rate is reduced, and if the interval is wide, the color material paste has a droplet form To increase the gas flow rate.

3 is an operation flowchart illustrating a printing method of a flat panel display according to the present invention. First, the contact execution mode or the droplet execution mode is set according to the distance between the display substrate and the printing apparatus (S31). The color material paste is applied to the plurality of paste through holes formed in the paste substrate (S32). In step S31, a squeegee can be used. The plurality of paste through hole patterns of the paste substrate and the plurality of gas through hole patterns of the gas substrate and the paste spraying positions of the display substrate, that is, the pixel patterns, are aligned (S33). Next, the gas supply means injects and injects a predetermined amount of gas so that the color material paste applied to the plurality of paste through holes of the paste substrate is transferred to the display substrate (S34). Next, the gas substrate is moved (S35), and steps S33 to S34 are repeated, and after the color material pastes of all the paste through holes have been completed, the process is repeated from step S32. The printing is finished when the color material paste is transferred to all the paste spraying positions on the display substrate.

4 is a configuration diagram of a printing apparatus for a flat panel display according to a second embodiment of the present invention. FIG. 4A illustrates a state in which the printing apparatus is driven in the contact execution mode, and FIG. 4B illustrates a state in which the printing apparatus is driven in the droplet migration mode. The concept of the contact execution mode and the droplet execution mode is the same as in FIG.

The difference in construction between the first embodiment of FIG. 2 and the fourth embodiment of FIG. 4 is the structure of the gas substrate. That is, the first embodiment of FIG. 2 uses a gas substrate in which a plurality of gas through holes corresponding to one-to-one correspond to the paste through holes, but the second embodiment of FIG. 4 uses a plurality of paste through holes in the gas substrate at one time. The slit nozzle 41 which can be supplied is used.

In the method of printing a flat panel display according to the present invention of FIG. 3, a gas substrate having a plurality of gas through holes formed therein may be replaced by a slit nozzle. To be implemented on the display board.

In the first embodiment of FIG. 2, since the paste through hole and the gas through hole are aligned one-to-one, there is a disadvantage in that the alignment is difficult. However, the gas pressure is applied to each gas through hole so that the color material paste is cleanly transferred. On the other hand, in the second embodiment of FIG. 4, since the slit nozzle supplies gas to a plurality of paste through holes at once, alignment is easy, but the color material paste may not be transferred cleanly, and the pattern may be distorted.

FIG. 5A is a three-dimensional schematic diagram of the printing apparatus for a flat panel display according to the first embodiment of the present invention, and FIG. 5B is a three-dimensional schematic diagram of the printing apparatus for a flat panel display according to the second embodiment of the present invention.

FIG. 6 is a photograph showing a fluorescent layer pattern formed by using a printing apparatus for a flat panel display according to the present invention, showing that a good fluorescent layer pattern can be efficiently formed.

In the present invention, the gas substrate and the paste substrate may be made of metal, silicon, ceramic, and polymer. The gas through holes and paste through holes formed in the gas substrate and the paste substrate can be processed using etching, laser drilling and electroforming processes.

The paste through hole formed in the paste substrate can be processed into various shapes such as round, rectangular, and rhombus depending on the display substrate, and the paste through hole has a nozzle shape with a certain angle so that the color material paste can be stably transferred by gas pressure. It can be manufactured, and the nozzle angle is in the range of 0 to 60 degrees. In addition, surface treatment such as Teflon coating, DLC (diamond like carbon) coating, and carbon coating can be performed around the paste through hole so that the color material paste is easily sprayed onto the paste through hole without being wet.

In addition, in the exemplary embodiment of the present invention, only one gas substrate and a slit nozzle are described, but a plurality of gas substrates and slit nozzles may be used. By using a plurality of gas substrates and slit nozzles, the fluorescent layer, color filter layer, and organic light emitting layer of a large area flat panel display can be formed at high speed, thereby improving productivity.

The technical spirit of the present invention has been described above with reference to the accompanying drawings, but this is by way of example only for describing the best embodiment of the present invention and not for limiting the present invention. In addition, it is a matter of course that various modifications and variations are possible without departing from the scope of the technical idea of the present invention by anyone having ordinary skill in the art.

FIG. 1 is a schematic diagram showing the structure of a general plasma display device (PDP) as one type of flat panel display.

2 is a configuration diagram of a printing apparatus for a flat panel display according to a first embodiment of the present invention, (a) shows a state in which the printing apparatus is driven in the contact execution mode, and (b) shows a liquid drop mode in the printing apparatus. The state of driving is shown.

3 is an operation flowchart illustrating a printing method of a flat panel display according to the present invention.

4 is a configuration diagram of a printing apparatus for a flat panel display according to a second embodiment of the present invention, (a) shows a state in which the printing apparatus is driven in the contact execution mode, and (b) shows a liquid drop mode in the printing apparatus. The state of driving is shown.

FIG. 5A is a three-dimensional schematic diagram of the printing apparatus for a flat panel display according to the first embodiment of the present invention, and FIG. 5B is a three-dimensional schematic diagram of the printing apparatus for a flat panel display according to the second embodiment of the present invention.

Figure 6 is a fluorescent layer pattern photograph formed using a printing apparatus of a flat panel display according to the present invention.

Claims (17)

A paste substrate having a paste through hole disposed on the display substrate and filled with a color material paste; Gas injection means disposed on the paste substrate to inject gas into the paste through hole so that the color material paste is transferred to the display substrate; And an alignment means for aligning the display substrate and the paste substrate. The printing apparatus of claim 1, wherein the paste substrate has a plurality of paste through holes matching the pixel pattern of the display substrate. 3. The gas injection means according to claim 1 or 2, wherein the gas injection means includes a gas substrate through which a gas through hole matching one-to-one is formed in the paste through hole so that the gas is individually supplied to the paste through hole. And a gas supply means arranged at an upper portion to supply gas to the gas substrate. 3. The gas injection means according to claim 2, wherein the gas injection means comprises a slit nozzle for simultaneously supplying gas to the plurality of paste through holes, and a gas supply means disposed above the slit nozzle to supply gas to the slit nozzle. Printing apparatus of a flat panel display, characterized in that. The printing apparatus of claim 1, wherein the flow rate of the gas is controlled according to a distance between the display substrate and the paste substrate. 6. The method of claim 5, wherein the flow rate of the gas is controlled so that the color material paste can be shifted by surface tension if the distance between the display substrate and the paste substrate is shorter than the maximum expansion distance of the color material paste. Printing device for flat panel displays. The flat plate of claim 5, wherein the flow rate of the gas is controlled so that the color material paste can be transferred into droplet form when the distance between the display substrate and the paste substrate is longer than the maximum expansion distance of the color material paste. Printing device on display. The printing apparatus for a flat panel display according to claim 1 or 2, wherein a cross section of the paste through hole has a cylindrical, rectangular, or rhombic shape. The printing apparatus for a flat panel display according to claim 1 or 2, wherein the paste through hole has a nozzle shape having an angle in a range of 0 degrees to 60 degrees. The printing apparatus of claim 1 or 2, wherein the paste through hole is formed with a Teflon coating, a DLC (diamond like corbon) coating, or a carbon coating. A paste coating step of filling a color material paste into a paste through hole formed in the paste substrate; An alignment step of aligning the paste through hole on the display substrate; And a gas injection step of injecting a gas into the paste through hole on the paste substrate so that the color material paste is transferred to the display substrate. 12. The method of claim 11, wherein the paste substrate has a plurality of paste through holes matching the pixel pattern of the display substrate. The method of printing a flat panel display according to claim 11 or 12, wherein the gas injection step supplies gas to the paste through hole individually by using a gas through hole that is matched one-to-one to the paste through hole. . 13. The method of claim 12, wherein the gas spraying step supplies gas to the plurality of paste through holes simultaneously using a slit nozzle. The method of claim 11, wherein, in the gas injection step, the flow rate of the gas is controlled according to a distance between the display substrate and the paste substrate. 16. The method of claim 15, wherein if the distance between the display substrate and the paste substrate is shorter than the maximum expansion distance of the color material paste, the flow rate of the gas is controlled so that the color material paste can be shifted by surface tension. Printing method of flat panel display. The flat plate of claim 15, wherein the flow rate of the gas is controlled so that the color material paste can be transferred into droplet form when the distance between the display substrate and the paste substrate is longer than the maximum expansion distance of the color material paste. How to print the display.

Images