KR100801681B1 - Method for fabricating an alignment film of a liquid crystal display device - Google Patents

Abstract

The present invention relates to a method for forming an alignment film of a liquid crystal display device.

Conventionally, the mask pattern which prints the said oriented film on a board | substrate was comprised differently according to the model of a liquid crystal display device.

Accordingly, a problem arises in that the ratio of the time required to clean the printing equipment to the time required to replace the mask pattern according to each model during the process of forming (printing) the alignment film increases, resulting in a decrease in productivity.

The present invention for solving the above problem relates to a method of forming an alignment layer using the mask pattern using only a beta mask (mask without a pattern) irrespective of the model of the liquid crystal display device.

Forming the alignment layer according to the present invention can reduce the additional cost for manufacturing a mask of a complex pattern, and can save the process time by eliminating the replacement time and cleaning time of the mask for each model resulting in improved productivity Can be obtained.

Description

Method for fabricating an alignment film of a liquid crystal display device             

1 is a flowchart schematically illustrating an alignment film forming process;

2 is a cross-sectional view showing a conventional alignment film forming method using an alignment film coating apparatus,

3 is a cross-sectional view illustrating the shape of an alignment layer for each model of the liquid crystal display device;

4 is a cross-sectional view showing an alignment film forming method according to the present invention using an alignment film coating apparatus,

5A to 5B are plan views and cross-sectional views illustrating transparent insulating substrates used as an array substrate for a liquid crystal display according to the present invention;

6A to 6C are cross-sectional views sequentially illustrating an alignment film forming process according to the present invention.

<Description of the symbols for the main parts of the drawings>

110: transparent insulating substrate 112: embossed pattern on the surface of the insulating substrate

115: roller 117: mask

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display (LCD), and more particularly, to a method of forming an alignment film, which is one of elements formed on opposite surfaces of upper and lower substrates of a liquid crystal display.

In general, the liquid crystal display device is a device using the optical anisotropy of the liquid crystal.

That is, when a voltage is applied, the molecular arrangement of the liquid crystal changes according to the intensity of the electric field, and the image is expressed by using a property that can control light according to the molecular arrangement of the liquid crystal. It consists of a liquid crystal filled between a substrate and it.

The manufacturing process of the liquid crystal display device as described above will be briefly described as follows.

First, a lower substrate of the two substrates forms a plurality of switching elements such as thin film transistors through a plurality of deposition, photo-lithography, and etching processes. Pixels corresponding to each switching device are configured in a matrix form, and an array pattern is formed in which wiring is crossed around the switching device, and a pad part is formed at one end of each of the wirings.

In addition, a common electrode is formed on a surface of the upper substrate facing the lower substrate, and a color filter is further attached when a color image is to be expressed.                         

Next, an alignment film is formed on the upper and lower substrates according to the alignment characteristics of the liquid crystal filled between the upper substrate and the lower substrate.

Next, after attaching the upper substrate and the lower substrate with a predetermined sealant, a liquid crystal panel is completed by filling an arbitrary liquid crystal in the space between the two substrates attached thereto.

The process of forming the alignment film on the substrate is essential for the following reasons.

The liquid crystal display device uses the electro-optic effect of the liquid crystal, and this electro-optic effect is determined by the anisotropy of the liquid crystal itself and the molecular arrangement state of the liquid crystal.

In addition, the control of the molecular arrangement of the liquid crystal has a great influence on stabilizing the display quality of the liquid crystal display device.

Therefore, it is the role of the alignment film to impart a single crystal order to the liquid crystal and to allow a regular response in literally one liquid crystal molecule.

Such an alignment film is divided into an inorganic alignment film and an organic alignment film, and in particular, many polyimide alignment films are used among organic alignment films.

The organic alignment film is subjected to a rubbing process after forming and curing the organic polymer film on the substrate by a rotary coating method or a printing coating method.

The rubbing process serves to give an alignment direction to the liquid crystal molecules by defining an alignment angle on the surface of the alignment layer.

1 is a flowchart summarizing the formation process of the alignment film.                         

As shown, the alignment film forming process can be largely divided into three steps.

First, an alignment layer is formed by applying an alignment material to a substrate (ST1). Second, curing is performed at a predetermined temperature to give strength to the alignment layer (ST2).

Third, by performing a rubbing treatment on the surface of the cured alignment film, the alignment film on which the micro grooves are formed can be completed (ST3).

Hereinafter, a conventional method of forming an alignment layer will be described with reference to the drawings.

FIG. 2 is a conventional method of coating an alignment layer on a glass substrate 10 using a plurality of rolls engaged with each other, including a doctor roll 11, anilox roll 13, Printing equipment consisting of a printing roll 15 and a rubber sheet 17 is used.

Of the plurality of rolls, the doctor roll 11 is engaged with the anilox roll 13 and the printing roll 15 is configured to engage with the anilox roll 13.

As shown in the figure, a fine groove 13a is formed on the side surface of the anilox roll 13.

In addition, a rubber plate (print mask) 17 having an arbitrary pattern is attached to one surface of the printing roll 15.

The pattern of the rubber plate 17 is an embossed pattern, so that an alignment layer may be printed on a portion of the surface of the array substrate except for a portion to which an adhesive is applied and a portion to form a pad.                         

Looking at the method of forming the alignment layer on the glass substrate using a printing equipment having the configuration as described above are as follows.

First, the glass substrate 10 is fixed to an arbitrary fixing means 12.

Next, any alignment material is sprayed onto the anilox roll 13 in the above-described configuration.

As described above, when a printing apparatus composed of a plurality of rolls is operated, the doctor roll 11 rotates to engage with the anilox roll 13 and receives the alignment material sprayed on the anilox roll 13. It is deposited in the fine groove (13a) of the anilox roll 13, and the alignment material deposited in the anilox roll 13 continuously is the anilox roll 13 and the printing roll 15 It is transferred again to the rubber plate 17 of the said printing roll 15 by engaging.

Next, as the alignment material transferred to the rubber plate, the alignment roll 21 is formed on the substrate 10 in accordance with the embossed pattern of the rubber plate 17 as the printing roll 15 rotates.

In this case, the embossed pattern varies in size depending on the model (size of the liquid crystal panel) of the liquid crystal display device to be manufactured. Accordingly, as illustrated in FIGS. 3A to 3C, the alignment layer 21 may be formed on the substrate 10 in various forms.

Next, a step of curing the alignment film 21 formed on the substrate 10 at a predetermined temperature is performed, and a step of rubbing the surface of the cured alignment film 21 using a rubbing roll (23 in FIG. 2). This is going on.                         

An alignment layer may be formed on the glass substrate by the method described above.

However, in the conventional alignment film forming method as described above, since the rubber plate varies depending on the model of the liquid crystal display device during the printing defense, the rubber plate should be replaced when forming the alignment film according to the desired model. In addition, the printing equipment should be cleaned thoroughly after each replacement.

If the cleaning is not cleaned, the substrate coated with the alignment layer due to contamination is very likely to be stained or pin holes during the curing process.

As a result, in the conventional method, the time for replacing the rubber plate and the cleaning time not only slow down the process time for forming the alignment film, but also cause an alignment film failure.

Therefore, the present invention for solving the above-described problem is prepared a substrate consisting of a rectangular embossed pattern to fit the size of the panel for each model.

When the substrate is used, the alignment film is printed only on the surface of the embossed pattern even when the alignment film is printed using a simple rubber plate. Thus, even when a single mask is used, an array substrate is formed according to a desired model. This is possible.

Therefore, the object of the present invention is to improve the productivity through the process time reduction and cost reduction in manufacturing the liquid crystal panel by proposing the alignment film printing method of the present invention.

According to an aspect of the present invention, there is provided a method of forming an alignment layer, comprising: preparing a substrate having a plurality of rectangular embossed patterns formed on a surface thereof; Winding a print mask without a pattern on a printing roll configured in the alignment film printing equipment; Coating an alignment material on the rubber plate; Rotating the printing roll so that the surface of the relief pattern and the surface of the printing mask coated with the alignment film are in contact with each other to print the alignment film on the rectangular surface; And performing a rubbing process on the surface of the printed alignment layer.

The substrate is characterized in that the transparent glass or plastic.

The rectangular shape may be configured differently according to the model of the liquid crystal panel for each insulating substrate.

Example

The present invention is characterized in that an alignment film is formed using a mask pattern composed of a single shape regardless of the model (size) of the liquid crystal display.

4 is a cross-sectional view showing an alignment film printing method according to the present invention using an alignment film printing apparatus.

As shown, the alignment film printing apparatus is a method of coating the alignment film on the glass substrate 110 by using a plurality of rolls interlocking, doctor roll (111), anilox roll (anilox roll) 113, a printing roll 115 and a rubber plate (mask) 117.

The rubber plate is used as a mask, which does not form a pattern (β printing mask) in the present invention unlike the conventional art.

The configuration and operation of the rolls are the same as in the above-described conventional description, and thus description thereof is omitted.

A feature of the present invention is that instead of using a simple printed mask (rubber plate) without a pattern, a substrate having an embossed pattern having the same size as the model size of the liquid crystal display device is used, so that the alignment layer is printed only on the surface of the embossed pattern. will be.

5A and 5B are a plan view and a cross-sectional view, respectively, of a substrate shaped according to the present invention.

As shown, a plurality of rectangular embossed patterns 112 are formed on the large-area substrate 110 to suit the size of the desired model.

The plurality of rectangular embossed patterns 112 are defined by a method of forming grooves 114 around the rectangular shape.

In this case, when the height of the substrate 110 is t, the groove 114 has a value of a. Therefore, the height of the relief pattern 112 is t-a.

As described above, the substrate having a shape as described above may be manufactured by molding the shape as described above from the beginning using transparent glass or plastic.                     

A method of forming an alignment layer using the substrate configured as described above will be described in detail with reference to FIGS. 6A to 6C.

6A to 6C are cross sectional views sequentially showing the alignment film forming process according to the present invention.

First, as shown in FIG. 6A, a large area transparent insulating substrate including a plurality of embossed patterns having a rectangular planar shape is prepared.

Next, the printing roll 115 on which the mask (β-mask) 117 without a pattern is wound on the substrate 110 is turned.

An alignment material (not shown) is coated on the surface of the mask 117, and the mask 117 contacts the surface of each embossed pattern 112 while rolling the upper portion of the substrate 110.

In this case, the planar area of the embossed pattern 112 may be variously defined according to a desired model.

Accordingly, unlike the related art, since a single mask having a single shape can be used to form alignment films according to various models, alignment films can be continuously formed on array substrates of various models without changing the mask for each model.

 As shown in FIG. 6B, the alignment material printed on the mask 117 is coated on the surfaces of the plurality of embossed patterns 112 formed on the substrate 110 to form the alignment layer 116.

Next, FIG. 6C is a cross-sectional view of the substrate 110 subjected to the rubbing process as described above. After the alignment layer is formed on the surface of the relief pattern 112, the alignment layer is formed using a predetermined means. Rubbing processing to make a fine groove 118 in the surface of the (116) is to proceed.

The alignment layer may be formed on the substrate through the alignment layer forming method according to the present invention as described above.

Use of the alignment film forming method according to the present invention has the following effects.

That is, a method of forming an alignment layer by defining a plurality of rectangular patterns having a desired shape by embossing the surface of the substrate instead of forming a mask pattern, and passing through the surfaces of the embossed pattern by using a single mask. Because of,

First, there is no need to manufacture a mask pattern for each model, thereby reducing the manufacturing cost.

Second, since a single mask pattern is used, it is not necessary to change the mask for each model during the alignment layer forming process, and thus the time required to replace the mask and the cleaning process during the replacement can be omitted, thereby saving time.

Therefore, there is an effect that productivity is improved.

Claims (5)

Preparing a substrate having a plurality of embossed patterns formed on a surface thereof; Winding a print mask without a pattern on a printing roll configured in the alignment film printing equipment; Coating an orientation material on the print mask; Printing the alignment layer on the surface of the relief pattern by rotating the printing roll to bring the surface of the print mask into contact with the relief pattern; Performing a rubbing process on the surface of the printed alignment layer; An alignment film forming method comprising a. The method of claim 1, And the substrate is a transparent glass or plastic. The method of claim 1, The embossed pattern has a rectangular planar shape and the rectangular area may be configured differently according to the model of the liquid crystal panel. delete delete

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