KR100945348B1 - Method for forming liquid crystal layer of liquid crystal display device - Google Patents

Abstract

The present invention relates to a liquid crystal layer forming method of a liquid crystal display device, the liquid crystal forming method comprising the steps of preparing a container containing a liquid crystal and a printing roll formed with a concave pattern; Dipping a portion of the printing roll into a liquid crystal container; Filling the inside of the concave pattern of the printing roll with the liquid crystal contained in the container while rotating the printing roll; And transferring the liquid crystal filled in the printing roll to the substrate.

Description

Liquid crystal layer formation method of a liquid crystal display element {METHOD FOR FORMING LIQUID CRYSTAL LAYER OF LIQUID CRYSTAL DISPLAY DEVICE}

1 is a view showing a liquid crystal injection device by a vacuum injection method.

2A to 2B illustrate a liquid crystal forming process using gravure printing according to a first embodiment of the present invention.

3 is a diagram illustrating a mother substrate on which a plurality of unit panels are formed.

4A to 4C illustrate a liquid crystal forming process using an offset printing method as a second embodiment according to the present invention.

5A to 5C illustrate a liquid crystal forming process using a gravure offset printing method according to a third embodiment of the present invention.

6A to 6C illustrate a liquid crystal forming process using a flexo printing method according to a fourth embodiment of the present invention.

*** Explanation of symbols for main parts of drawing ***

150, 250, 350, 450: printing roll

280, 380, 480: Cliché

130, 230, 330, 430: liquid crystal layer

The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly, to a method for forming a liquid crystal layer through a printing method.

Generally, a liquid crystal display (Liquid Crystal Display) is a liquid crystal composed of a plurality of liquid crystal cells arranged in a matrix form and a plurality of control switches for switching the video signal to be supplied to each of these liquid crystal cells The amount of light beam supplied from the backlight unit is adjusted to the panel to display a desired image on the screen.

The liquid crystal display device includes a liquid crystal panel in which a liquid crystal is formed between the thin film transistor substrate and the color filter substrate; A driving circuit unit including a printed circuit board (PCB) to which various circuit elements for driving the liquid crystal panel are attached; It is arranged in the lower part of the liquid crystal panel and consists of a backlight unit for supplying a light source, and can be miniaturized compared to the CRT, so that personal computers, notebook computers (NoTebook Personal Computer; NTPC), as well as office automation such as copy machines, etc. It is widely used to carry devices, mobile phones and pagers.

In the liquid crystal display device configured as described above, a brief manufacturing process and operation of the liquid crystal panel will be described.

First, a thin film transistor substrate on which a plurality of TFTs and pixel electrodes are formed, and a color filter substrate on which a color filter and a common electrode are formed are prepared.

Thereafter, an alignment layer forming process, a cell gap forming process, and a cutting process for alignment of the liquid crystal molecules are performed.

The alignment layer forming process includes a coating and rubbing process of a polymer thin film, and the polymer thin film is generally referred to as an alignment film, and a polyimide series is mainly used. The alignment layer is to be coated with a uniform thickness throughout the substrate, rubbing refers to rubbing the alignment layer in a predetermined direction using a cloth, the main process to determine the initial alignment direction of the liquid crystal, by rubbing of the alignment layer Since it is possible to drive and has a uniform display characteristic, it should be made uniformly in a certain direction.

After the alignment film forming process is completed, a failure turn is formed around the active region. The fail-turn formation is a process of forming a thermosetting resin in a desired pattern constantly. In the liquid crystal panel, the fail-turn has two functions of forming gaps for injecting liquid crystals and not leaking the injected liquid crystals.

 After the fail turn forming process is completed, a spacer is disposed on the upper portion of the substrate to uniformly maintain the cell gap, and then the process of bonding the upper substrate, which is the color filter substrate, and the lower substrate, which is the thin film transistor array substrate, are performed through the fail turns. . In this case, the spacer scattering step may be omitted, and the spacer pattern may be previously formed on the color filter substrate. The bonding arrangement of the upper substrate and the lower substrate is determined by the margin given in the design of each substrate, and usually a precision of several micrometers is required. If the two substrates are out of the bonding error range, light leaks out, so that the desired image quality characteristics cannot be expected when the liquid crystal cell is driven.

After the bonding process as described above, the liquid crystal panel produced through the above process is cut for each unit panel. The substrate cutting process consists of a scribe process that forms a vertical crack on the surface of the substrate using a diamond wheel that is harder than a glass substrate, and a break process that applies a force to the substrate on which the crack is formed. .

Finally, after completing the scribe / break process as described above, the liquid crystal is injected into each liquid crystal injection hole cut into each unit panel to complete the panel.

As a method of injecting a liquid crystal, a vacuum injection method of vacuuming an inside of a cell formed by a failure turn and then injecting a liquid crystal using a pressure difference from the outside of the cell is most widely used.

1 shows a liquid crystal injection device by a vacuum injection method. Here, in order to improve productivity, several liquid crystal panels are comprised so that liquid crystal injection may be carried out simultaneously.

The liquid crystal injection process by the vacuum injection method is carried out through the following steps. 40) is used to lower the pressure in the chamber 10 to several mTorr and maintain for a sufficiently long time to complete the defoaming step to remove the fine air contained in the liquid crystal. Thereafter, the liquid crystal injection hole 45 of the liquid crystal panel 30 touches the liquid crystal 20a, releases the vacuum inside the chamber, and makes the atmospheric pressure. At this time, the vacuum release method is made by injecting nitrogen gas (N2) through a tube connected to the outside of the chamber.

When the inside of the chamber 10 is changed to the atmospheric pressure as described above, the liquid crystal 20a contained in the container 20 is injected into the cell of the liquid crystal panel 30 by the pressure difference and the capillary phenomenon. At this time, the method of injecting the liquid crystal is divided into a dipping method of dipping the entire side surface of the liquid crystal inlet of the panel in the liquid crystal and a touch method of contacting only the liquid crystal inlet portion of the panel to the liquid crystal. The dipping method has a disadvantage in that a large amount of liquid crystal is required and the liquid crystal is easily contaminated, but the touch method requires a small amount of liquid crystal as compared to the dipping method, and thus, has been widely used in recent years. In addition, since the liquid crystal injection takes several tens of hours or more to complete the liquid crystal injection through the above method, the liquid crystal injection process may be divided into two-stage chambers in which the liquid crystal injection process is continuously performed in order to increase productivity.

However, in the vacuum injection method as described above, as the size of the substrate increases, the liquid crystal injection time also becomes longer, which is not suitable for large area.

Accordingly, the present invention has been made to solve the above problems, and to provide a liquid crystal layer forming method that can shorten the liquid crystal forming process time due to the large area by forming the liquid crystal on the substrate through a printing method.

Other objects and features of the present invention will be described in detail in the configuration and claims of the following invention.

Liquid crystal forming method of the present invention for achieving the above object comprises the steps of preparing a container containing a liquid crystal and a printing roll formed with a concave pattern; Dipping a portion of the printing roll into a liquid crystal container; Filling the inside of the concave pattern of the printing roll with the liquid crystal contained in the container while rotating the printing roll; And transferring the liquid crystal filled in the printing roll to the substrate.

Alternatively, the present invention comprises the steps of applying a liquid crystal to the convex portion of the cliché formed with a convex pattern; Transferring the liquid crystal applied to the convex portion onto a printing roll; Transferring the liquid crystal transferred to the printing roll to the substrate, it is possible to contact the substrate without the printing roll, the liquid crystal is applied directly to the substrate, and then a method for separating. Instead of the convex pattern in the cliché, a concave pattern may be formed to fill the recess with a liquid crystal.

Alternatively, the liquid crystal layer may be formed by filling a liquid crystal into the cliché groove without using a printing roll, then contacting the substrate with the cliché, and then separating it again.

Hereinafter, the liquid crystal forming process of the present invention will be described in detail with reference to the accompanying drawings.

2A to 2B illustrate a liquid crystal layer forming process using a gravure printing method as a first embodiment according to the present invention.

First, as shown in FIG. 2A, a printing roll 150 in which a container 120 containing liquid crystals 120a and concave grooves 160 are formed for each unit panel is prepared, and then the printing roll 150 is formed into a liquid crystal 120a. Soak in). At this time, since the liquid crystal may be contaminated when the printing roll 150 is immersed in a large amount, only the groove 160 is completely immersed. Next, while rotating the printing roll 150 while the printing roll 150 is immersed in the liquid crystal, the liquid crystal 120b filled in the groove is uniformly pushed by the doctor blade 170 so as to have a flat surface. give.

When all of the liquid crystal is filled in the grooves of the printing roll through the above process, as shown in FIG. 2B, the liquid crystal layer 120b filled in the printing roll 150 is transferred to the substrate 100, thereby forming a liquid crystal layer ( 130). In this case, the substrate 100 may be a thin film transistor substrate in which the thin film transistor is arranged in a matrix form or a color filter substrate in which a color filter that substantially implements color is formed. As shown in FIG. 3, a plurality of unit panels 100a are formed on the substrate 100. Conventionally, after the thin film transistor and the color filter substrate are bonded, the liquid crystal is injected to each panel by cutting each unit panel. However, in the present invention, the liquid crystal is formed on a mother substrate on which the unit panels are formed before bonding. The layer formation time can be further shortened.

4A to 4C illustrate a liquid crystal forming process using an offset printing method as a second embodiment according to the present invention.

First, as shown in FIG. 4A, the surface of the offset plate 280 is coated so that the liquid crystal can be adhered well. At this time, the surface treatment is performed by applying a plasma treatment or a primer material. The region where surface treatment is performed on the offset plate 280 is a region where liquid crystal will be formed later.

Next, as shown in FIG. 4B, the liquid crystal 285 is applied only to a region where the surface treatment of the offset plate 280 is performed. The method of applying the liquid crystal to the offset plate 280 proceeds using a plurality of rolls, when the liquid crystal supplied from the liquid crystal supply portion passes between the rotating doctor roll and the enilox roll, the liquid crystal by the doctor roll Uniform liquid crystal is formed on the eniloxol. The liquid crystal is again transferred to the first printing roll which rotates in engagement with the eniloxroll. A convex pattern corresponding to the surface treatment area of the offset plate is formed on the first printing roll, so that the liquid crystal is transferred only to the convex pattern, and when the offset plate passes under the first printing roll, the liquid crystal is offset. Transition to the plate.

Next, as shown in FIG. 4C, the liquid crystal 285 applied to the offset plate 280 is transferred to the second printing roll 250, and then, as shown in FIG. 4D, a plurality of unit panels are provided. The liquid crystal layer 230 is formed by transferring the formed mother substrate 200.

The offset printing method as described above can form a lower liquid crystal thickness than other printing methods, and therefore is easy for FLC (ferroelectric liquid crystal) having a low cell gap. The cell gap of a typical liquid crystal panel is about 4.5 μm when using a ball spacer, and has a thickness of about 2 μm when the FLC is manufactured using a spacer previously patterned on a substrate as described above. At this time, the thickness of the liquid crystal may be increased by performing the offset printing process as described above at least twice.

5A to 5C illustrate a liquid crystal layer forming process using a gravure offset printing method as a third embodiment according to the present invention.

First, as shown in FIG. 5A, the liquid crystal is applied onto the cliché 280 on which the concave groove 385 is formed, and then on the cliché 280 to which the liquid crystal is applied using a doctor blade 310. By flattening, the liquid crystal 320a remains only in the region where the groove 385 is formed, and the liquid crystal buried elsewhere is completely removed.

Then, as shown in FIG. 5B, the printing roll 350 is brought into contact with the cliché 380, and then rotated to print the liquid crystal 320a filled in the groove 385 of the cliché 380. Transition to 350.

Next, as shown in FIG. 5C, the printing roll 350 in which the liquid crystal 320b is deposited is transferred onto the substrate 300 to form the liquid crystal layer 330.

The gravure offset printing method as described above uses liquid crystals only in necessary amounts, thereby preventing waste of liquid crystals.

6A to 6C illustrate a liquid crystal forming process using a flexo printing method as a fourth embodiment according to the present invention. The flexographic printing method is a method of forming a convex pattern on the cliché, applying a liquid crystal to the convex part, and then transferring the liquid crystal onto the substrate through a printing roll. (gravure offset) Same as printing method. Therefore, only the differences will be described here, and the description thereof will be omitted for the same process as the gravure offset printing process.

First, as illustrated in FIG. 6A, a cliché 480 having a convex pattern 485 formed in a region where liquid crystal is to be applied is prepared. Then, as shown in FIGS. 6B to 6C, the liquid crystal 420a is applied to a region where the convex pattern 485 is formed, and then transferred to the printing roll 450, and then transferred to the substrate 400. The liquid crystal layer 430 is formed.

Although not shown in the drawings in addition to the above-described method, a direct contact printing method is also possible in which a substrate is directly contacted with a cliché, and then separated, without using a printing roll.

When the liquid crystal layer is formed on the substrate through the printing method as described above, the liquid crystal layer may be simultaneously formed on the plurality of unit panels formed on the mother substrate by one rotation of the printing roll, thereby reducing the process time. As the size of the panel increases, if only the size of the roller is increased, the liquid crystal layer can be formed within a short time regardless of the size of the panel.

As described above, according to the present invention, by forming the liquid crystal of the liquid crystal display element through the printing method, compared to the conventional vacuum injection method, it is possible to reduce the process time and cost for forming the liquid crystal, in particular, productivity in a large area Can be further improved.

Claims (9)

delete delete delete Preparing an offset plate; Surface treatment such as plasma treatment or coating of primer material so that the liquid crystal can adhere to the surface of the offset plate; Supplying a liquid crystal between the doctor roll and the eniloxol which rotates at intervals to form a liquid crystal in the eniloxol; Transferring a liquid crystal of eniloxol to a first printing roll rotating at intervals from the eniloxol; Applying a liquid crystal transferred to the first printing roll to a region where surface treatment is performed in the offset plate; Transferring the liquid crystal applied to the offset plate to a second printing roll; Preparing a mother substrate on which a plurality of unit panels are formed; And Transferring the liquid crystal transferred to the second printing roll onto a mother substrate to form a liquid crystal layer on each unit panel; The liquid crystal layer forming method of the liquid crystal display element characterized by including the. delete delete delete delete delete

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