KR20050000572A - The method for fabricating retardation film and the method for fabricating liquid crystal display device using the same - Google Patents

Abstract

PURPOSE: A method for fabricating a phase retardation film and a method for manufacturing an LCD(Liquid Crystal Display) using the method are provided to rub an alignment film in the first direction and irradiate UV rays on the alignment film using a mask such that an exposed portion of the alignment film aligned in the first direction is aligned in the second direction, to thereby reduce the number of processing steps and form a multi-domain. CONSTITUTION: An alignment film(402) is formed on a substrate(400) and rubbed to align the alignment film in the first direction. A mask is placed above the alignment film and light is irradiated on the alignment film to align exposed portions of the alignment film in the second direction. A phase retardation film(403) is formed on the alignment film aligned in the first and second directions.

Description

The method for fabricating retardation film and the method for fabricating liquid crystal display device using the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a method of manufacturing a phase difference film capable of manufacturing a phase difference film having a plurality of optical axes and a method of manufacturing a liquid crystal display device using the same.

As the information society develops, the demand for display devices is increasing in various forms, and in recent years, liquid crystal displays (LCDs), plasma display panels (PDPs), electro luminescent displays (ELDs), and vacuum fluorescent displays (VFDs) have been developed. Various flat panel display devices have been studied, and some of them are already used as display devices in various devices.

Among them, LCD is the most widely used as a substitute for CRT (Cathode Ray Tube) for the use of mobile image display device because of the excellent image quality, light weight, thinness, and low power consumption, and mobile type such as monitor of notebook computer. In addition, it is being developed in various ways, such as a television for receiving and displaying broadcast signals, and a monitor of a computer.

As described above, although various technical advances have been made in order for the liquid crystal display device to serve as a screen display device in various fields, the task of improving the image quality as the screen display device has many advantages and disadvantages.

Therefore, in order to use a liquid crystal display device in various parts as a general screen display device, the key to development is how much high definition images such as high definition, high brightness, and large area can be realized while maintaining the characteristics of light weight, thinness, and low power consumption. It can be said.

Such a liquid crystal display device may be broadly divided into a liquid crystal display panel displaying an image and a driving unit for applying a driving signal to the liquid crystal panel, wherein the liquid crystal display panel includes a first substrate and a second substrate bonded to each other with a space. And a liquid crystal layer injected between the first and second substrates.

The first substrate (TFT array substrate) may include a plurality of gate lines arranged in one direction at a predetermined interval, a plurality of data lines arranged at regular intervals in a direction perpendicular to the gate lines, and the respective gates. A plurality of thin film transistors which are switched by signals of the gate line and a plurality of pixel electrodes formed in a matrix form in each pixel region defined by crossing a line and a data line, transmit a signal of the data line to each pixel electrode. Formed.

The second substrate (color filter substrate) includes a black matrix layer for blocking light in portions other than the pixel region, R, G, and B color filter layers for expressing color colors, and a common electrode for implementing an image. Is formed.

The first and second substrates have a predetermined space by spacers and are bonded by a sealant to form a liquid crystal between the two substrates.

Hereinafter, a structure of a general liquid crystal display device will be described with reference to the accompanying drawings.

1 is an exploded perspective view illustrating a general liquid crystal display device.

As shown in FIG. 1, a general liquid crystal display device includes a first substrate 1 and a second substrate 2 bonded to each other with the predetermined space, and between the first substrate 1 and the second substrate 2. It consists of the liquid crystal layer 3 injected into it.

More specifically, the first substrate 1 has a plurality of gate lines 4 arranged in one direction at regular intervals to define the pixel region P, and the direction perpendicular to the gate lines 4. A plurality of data lines 5 are arranged at regular intervals, and pixel electrodes 6 are formed in the pixel regions P, and portions where the gate lines 4 and the data lines 5 cross each other. A plurality of thin film transistors T are formed on and off according to the driving signal of the gate line 4 to apply the image signal of the data line 5 to each pixel electrode 6.

In addition, the second substrate 2 has a black matrix layer 7 for blocking light except portions of the pixel region P, and R and G for expressing color colors corresponding to the pixel regions P. FIG. , The B color filter layer 8 and the common electrode 9 for implementing the image are formed.

An alignment film (not shown) is formed on the surfaces of the first and second substrates 1 and 2 facing each other as described above, respectively, and rubbed to align the liquid crystal layer 3.

The thin film transistor T may include a gate electrode protruding from the gate line 4, a gate insulating film (not shown) formed on the front surface, an active layer formed on the gate insulating film above the gate electrode, and the data. The source electrode which protrudes from the wiring 5 and the drain electrode which oppose the said source electrode are comprised.

The pixel electrode 6 uses a transparent conductive metal having a relatively high light transmittance, such as indium-tin-oxide (ITO).

In the general liquid crystal display device configured as described above, since the alignment films formed on the first substrate 1 and the second substrate 2 are rubbed in one direction, between the first substrate 1 and the second substrate 2. All liquid crystal molecules of the formed liquid crystal layer 3 are oriented in the same direction.

However, in such a general liquid crystal display device, when voltage is applied, liquid crystal molecules near the surface of the alignment layer do not align vertically even when voltage is applied by the alignment regulating force of the alignment layer, and the polarized light has an optical anisotropy. When passing through (3), the retardation value is different when the liquid crystal layer 3 passes vertically and when it passes at an angle, and thus, a phase difference occurs, and thus the characteristic of transmitted light according to the viewing angle is different, thereby providing a clear image. none.

In order to compensate for optical anisotropy of such liquid crystal molecules, a liquid crystal display using a retardation film has been proposed.

2 is a cross-sectional view of a liquid crystal display device using a conventional retardation film.

As shown in FIG. 2, a liquid crystal display device using a conventional retardation film includes a first alignment layer 24a formed inside the first substrate 23a, the first substrate 23a, and the first substrate ( The second retardation film 22a and the first polarizing plate 21a formed outside the 23a and the second substrate 23b opposed to the first substrate 23a and bonded to the first substrate 23a with a space therebetween. ), A second alignment film 24b formed inside the second substrate 23b, a second retardation film 22b and a second polarizing plate 21b formed outside the second substrate 23b, and It consists of the liquid crystal layer 25 formed between the 1st board | substrate 23a and the 2nd board | substrate 23b.

The polarization axis directions of the first polarizing plate 21a and the second polarizing plate 21b are orthogonal to each other, and the alignment directions of the liquid crystal molecules formed on the liquid crystal layer 25 are -45 ° and + 45 °, respectively.

The liquid crystal molecules of the liquid crystal layer 25 use liquid crystals having a dielectric anisotropy of (+), and form pretilt angles in the vicinity of the first and second alignment layers 24a and 24b. When the voltage is applied, the liquid crystal molecules form almost 90 ° in the middle of the liquid crystal layer 25 according to the electric field formed perpendicular to the first and second substrates 23a and 23b.

Therefore, the white background mode is operated in the voltage-free state (V = 0), and the normal white mode is displayed in the black background mode in the voltage application state (V = Vmax).

The first and second retardation films 22a and 22b compensate for a phase difference felt by a user in a direction perpendicular to the substrates 23a and 23b and a change in viewing angle. It has a vertical optical axis.

And, as shown in Figure 2, by adjusting the retardation (retardation) of the retardation film can be optimized the black background mode when the voltage is applied.

Here, an alignment film (not shown) is formed between the substrates 23a and 23b and the retardation films 22a and 22b, respectively.

The alignment layer has a role different from that of the first and second alignment layers 24a and 24b, and the first and second alignment layers 24a and 24b serve to orient liquid crystal molecules of the liquid crystal layer 25. Meanwhile, each alignment layer formed between the substrates 23a and 23b and the retardation films 22a and 22b serves to form optical axes of the retardation films 22a and 22b.

Hereinafter, the manufacturing method of the retardation film with reference to the drawings in detail as follows.

3A to 3C are process cross-sectional views showing a conventional method for manufacturing a retardation film.

First, as shown in FIG. 3A, a substrate 300 is prepared, and an alignment layer 301 is formed and cured on the entire surface of the substrate 300.

Next, as shown in FIG. 3B, the alignment layer 302 is rubbed and oriented in one direction.

Subsequently, when the retardation film 303 is coated on the entire surface of the alignment film 302 oriented in one direction, as shown in FIG. 3C, the retardation film having an optical axis in the same direction as the alignment direction of the alignment film 301 ( 303) can be obtained.

However, such a conventional method of manufacturing a retardation film has the following problems.

The retardation film manufactured by the conventional retardation film manufacturing method has only one optical axis in the same pixel, and thus cannot form a multi-domain.

Meanwhile, in order to implement one or more optical axis directions of the retardation film, the alignment layer may be first rubbed in one direction to be aligned, and a predetermined area of the first rubbed alignment layer may be covered and the exposed region of the alignment layer may be in a different direction from the one direction. Multi-domains can be realized by secondary rubbing, but this method has a disadvantage in that the number of processes increases as the number of multi-domains to be formed increases.

The present invention has been made to solve such a problem, and rubbing the alignment film in the first direction, and the exposed area of the alignment film oriented in the first direction using a mask is oriented in the second alignment direction It is an object of the present invention to provide a method for manufacturing a retardation film capable of reducing the number of steps and forming a multi-domain by UV irradiation and a liquid crystal display device using the same.

1 is an exploded perspective view of a general liquid crystal display device

2 is a cross-sectional view of a liquid crystal display device using a conventional retardation film

Figure 3a to 3c is a process perspective view showing a conventional method for producing a retardation film

4a to 4d is a process perspective view showing a method of manufacturing a retardation film according to the present invention

5 is a plan view of a retardation film according to the present invention

6A to 6C are process perspective views of a liquid crystal display according to a first embodiment of the present invention.

7A to 7C are process perspective views of a liquid crystal display according to a second exemplary embodiment of the present invention.

* Explanation of symbols on the main parts of the drawings

400 substrate 402 alignment film

403: retardation film

According to an aspect of the present invention, there is provided a method of manufacturing a retardation film, the method including: forming an alignment layer on a front surface of a substrate and rubbing the alignment layer in a first direction; Arranging a mask on top of the alignment layer oriented in the first direction and irradiating light to align the exposed region of the alignment layer in a second direction; And forming a phase difference film on the entire surface of the alignment film oriented in the first direction and the second direction.

Here, the light is characterized by using linearly polarized light, non-polarized light, partial polarized light, unpolarized light and ultraviolet light.

It is characterized by further comprising a step of curing the alignment film before the alignment treatment in the first direction.

The retardation film is characterized by using any one of a uniaxial film and a biaxial film.

The first direction and the second direction are characterized in that the direction perpendicular to each other.

In addition, a method of manufacturing a liquid crystal display device using such a phase difference film includes the steps of: forming a first and a second alignment film inside the first substrate and the second substrate and rubbing them, respectively, to perform alignment treatment in the first direction; Arranging a mask on top of the first and second alignment layers oriented in the first direction and irradiating light to align the exposed regions of the first and second alignment layers in a second direction, respectively; Forming first and second retardation films on front surfaces of the first and second alignment layers oriented in the first direction and the second direction, respectively; Forming and aligning third and fourth alignment layers on the entire surface of the first and second retardation films, respectively; Bonding the first substrate to the second substrate such that the third alignment layer and the fourth alignment layer face each other; And forming a liquid crystal layer between the bonded first substrate and the second substrate.

Here, the first and second retardation film is characterized by using any one of a uniaxial film and a biaxial film.

The liquid crystal layer is formed by a liquid crystal dropping method or a liquid crystal injection method.

The first and second alignment films are formed outside the first and second substrates, respectively, and the third and fourth alignment films are formed inside the first and second substrates.

Hereinafter, a method of manufacturing a retardation film according to the present invention will be described in detail with reference to the accompanying drawings.

4A to 4D are process perspective views illustrating a method of manufacturing a retardation film according to the present invention, and FIG. 5 is a plan view of the retardation film according to the present invention.

First, the substrate 400 is prepared, and the substrate 400 is cleaned to remove foreign matters and particles.

Next, as shown in FIG. 4A, the alignment layer 402 is formed on the entire surface of the substrate 400 that has been cleaned.

Here, there are various methods of forming the alignment layer 402, such as spin, spray, dip, and printing. In the present invention, the alignment layer 402 is formed by a printing method that is commonly used.

The alignment layer 402 may be formed of a material such as polyamide, a polyimide compound, polyvinyl alchol (PVA), or polyamic acid to form the alignment layer 402. It may be formed, and may be used a photoreactive material such as polyvinyl cinnamate (PVC), poly siloxane cinnamate (PSCN) or cellulose cinnamate (CelCN) -based compounds.

The alignment film of the aforementioned material is oriented through the rubbing process, and the alignment film of the photoreactive material described later is oriented through the photo alignment process.

In the printing method, the alignment film 402 is formed using an alignment film printing apparatus, and as shown in FIG. 4A, the polyimide solution 405 which is an alignment film raw material solution stored in the raw material supply container 406 of the alignment film printing apparatus. ) Is conveyed through the raw material supply pipe 407, the polyimide liquid 405 is supplied dropwise to the contact surface of the doctor roll 409 and the anilox roll 410 which are mutually rotated through the dispenser 408.

Subsequently, the polyimide liquid 405 supplied dropwise to the contact surface between the doctor roll 409 and the anilox roll 410 is uniformly opened between the doctor roll 409 and the anilox roll 410, and as a result, The polyimide liquid 405 is apply | coated uniformly to the surface of the printing roll 411.

Then, the polyimide liquid 405 uniformly applied to the printing roll 411 is printed on the entire surface of the substrate 400 placed on the printing table 404, and the printed polyimide liquid 405 is predetermined. The alignment film 402 is formed by curing at a temperature.

Next, as shown in FIG. 4B, the substrate 400 on which the alignment film 402 is formed is mounted on the upper surface of the stage 415 by the alignment film printing apparatus, and the rubbing roll 412 is advanced in the arrow direction. .

At this time, the rubbing cloth 414 of the rubbing roll 412 connected to the support 414 is in contact with the alignment layer 402 of the substrate 400 seated on the bottom thereof, and then the rubbing roll 412 rotates. The rubbing cloth 414 formed on the rubbing roll 412 leaves a groove in the alignment layer 402 to be oriented in the first direction.

Subsequently, as shown in FIG. 4C, the mask 417 is aligned on the alignment layer 402 oriented in the first direction, and the light 418 is irradiated.

As the light 418 used in the light irradiation, light such as linearly polarized light, non-polarized light, partial polarized light, unpolarized light, and ultraviolet (UV) light may be used.

In the light irradiation, it is preferable to irradiate such that the alignment layer 402 oriented in the first direction is oriented in a second direction perpendicular to the first direction.

The mask 417 is composed of a light transmitting portion 416a for transmitting the light 418 and a light shielding portion 416b for blocking the light 418, thereby blocking the light transmitting portion 416a of the mask 417. Passed light 418 is irradiated on the alignment layer 402 oriented in the first direction, the light 418 irradiated to the light shielding portion 416b of the mask 417 is blocked.

Accordingly, light 418 is selectively irradiated to only part of the exposed area on the alignment layer 402 oriented in the first direction, so that the area to which the light 418 is irradiated is oriented in the second direction, and the remaining area is The state oriented in the first direction is maintained.

In this way, regions oriented in the first direction and regions oriented in the second direction are formed on the alignment layer 402.

Thereafter, as shown in FIG. 4D, the retardation film 403 is formed on the alignment film 402 oriented in the first and second directions, whereby the first and second directions of the alignment film 402 are formed. A retardation film 403 having an optical axis in the same direction as is formed.

Here, the retardation film 403 may use any one of a uniaxial film or a biaxial film.

In the embodiment of the present invention, a method of manufacturing the retardation film 403 having four regions has been described as an example, but by applying the method of manufacturing the retardation film 403 of the present invention, as shown in FIG. A retardation film having three regions can be produced.

Here, reference numeral 501, which has not been described, is an area having a first direction by rubbing, and 500 is an area having a second direction by light irradiation.

The manufacturing method of the liquid crystal display device according to the first exemplary embodiment of the present invention using such a retardation film will be described in detail with reference to the accompanying drawings.

6A through 6C are cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to a first embodiment of the present invention.

First, a color having a first substrate 600a, a black matrix layer, a common electrode, and a color filter layer on which a thin film transistor array including a gate line and a data line, a thin film transistor, and a pixel electrode arranged in a direction perpendicular to each other is formed. The second substrate 600b on which the filter array is formed is prepared.

In addition, the first and second substrates 600a and 600b are cleaned to remove foreign substances and particles.

Thereafter, as described above, the processes of FIGS. 4A to 4D are performed, and as shown in FIG. 6A, the first alignment layer 602a oriented in the first and second directions inside the first substrate 600a. ) And a first retardation film 603a having optical axes in the first and second directions.

Of course, a second retardation film 602b oriented in the first and second directions and a second retardation film 603b having optical axes in the first and second directions are sequentially formed inside the second substrate 600b.

Subsequently, as illustrated in FIG. 6B, a third alignment layer 604a for forming liquid crystal molecules of the liquid crystal layer is formed on the first retardation film 603a and subjected to alignment treatment.

Of course, a fourth alignment layer 604b is formed on the second retardation film 603b of the second substrate 600b.

Here, as the alignment layer material for forming each of the alignment layers 602a, 602b, 604a, and 604b, as described above, polyamide, polyimide compound, polyvinyl alchol (PVA), polyamic acid (Polyamic) An alignment layer may be formed using a material such as acid, and a photoreactive material such as polyvinyl cinnamate (PVC), poly siloxane cinnamate (PSCN), or cellulose cinnamate (CelCN) -based compound may be used.

The alignment film of the aforementioned material is oriented through the rubbing process, and the alignment film of the photoreactive material described later is oriented through the photo alignment process.

Next, as shown in FIG. 6C, the first and second substrates 600a and 600b have a sealant having a predetermined space by a spacer (not shown) and having a liquid crystal injection hole (not shown). And the liquid crystal layer 601 is injected between the two substrates 600a and 600b.

In this case, the liquid crystal layer 601 maintains a vacuum state between the first substrate 600a and the second substrate 600b bonded by the sealing material so that the inlet is immersed in the liquid crystal liquid so that the liquid crystal is formed by osmotic pressure. It forms by the liquid crystal injection method to inject.

In addition, after the appropriate amount of liquid crystal is dropped into the first substrate 600a or the second substrate 600b, a liquid crystal dropping method may be used in which the first substrate 600a and the second substrate 600b are bonded together.

On the other hand, such a retardation film may be formed on the outside of each substrate.

7A to 7C are cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to a second embodiment of the present invention.

First, a color having a first substrate 700a, a black matrix layer, a common electrode, and a color filter layer on which a thin film transistor array including a gate line and a data line, a thin film transistor, and a pixel electrode are arranged. The second substrate 700b on which the filter array is formed is prepared.

In addition, the first and second substrates 700a and 700b) are cleaned in order to remove foreign substances and particles.

Thereafter, as described above, the processes of FIGS. 4A to 4D are performed, and as shown in FIG. 7A, the first alignment layer 702a is oriented in the first and second directions outside the first substrate 700a. ) And a first retardation film 703a having optical axes in the first and second directions.

Of course, a second retardation film 702b oriented in the first and second directions and a second retardation film 603b having optical axes in the first and second directions are sequentially formed on the outer side of the second substrate 700b.

Subsequently, as shown in FIG. 7B, a third alignment layer 704a for forming the liquid crystal molecules of the liquid crystal layer 701 is formed inside the first substrate 700a and subjected to alignment treatment.

Of course, the fourth alignment layer 704b is also formed inside the second substrate 700b and subjected to alignment treatment.

Here, as the alignment layer material for forming each of the alignment layers 602a, 602b, 604a, and 604b, as described above, polyamide, polyimide compound, polyvinyl alchol (PVA), polyamic acid (Polyamic) The alignment layers 602a, 602b, 604a, and 604b may be formed using a material such as acid, and photoreactive materials such as polyvinyl cinnamate (PVC), poly siloxane cinnamate (PSCN), or cellulose cinnamate (CelCN) -based compounds. Can be used.

The alignment film of the aforementioned material is oriented through the rubbing process, and the alignment film of the photoreactive material described later is oriented through the photo alignment process.

Next, as shown in FIG. 7C, the first and second substrates 700a and 700b have a sealant having a predetermined space by a spacer (not shown) and having a liquid crystal injection hole (not shown). And the liquid crystal layer 701 is injected between the two substrates 700a and 700b.

Here, as a method for forming the liquid crystal layer 701 by injecting the liquid crystal, as described above, a liquid crystal injection method or a liquid crystal drop method may be used.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

As described above, the method of manufacturing the retardation film and the method of manufacturing the liquid crystal display using the same according to the present invention have the following effects.

First, since a retardation film having a plurality of optical axes can be manufactured in the same pixel, it is possible to compensate for viewing angles in various directions.

Second, since a retardation film having a plurality of optical axes can be manufactured at the same time using a rubbing process and a selective light alignment process using a mask, the number of processes and time can be shortened.

Claims (10)

Forming an alignment layer on the entire surface of the substrate and rubbing the alignment layer in a first direction; Arranging a mask on top of the alignment layer oriented in the first direction and irradiating light to align the exposed region of the alignment layer in a second direction; And forming a retardation film on the entire surface of the alignment film oriented in the first direction and the second direction. The method of claim 1, The light is linearly polarized light, non-polarized light, partial polarized light, non-polarized light and ultraviolet light manufacturing method of the phase difference film characterized in that it uses. The method of claim 1, A method for producing a phase difference film, further comprising the step of curing the alignment film before the alignment treatment in the first direction. The method of claim 1, The retardation film is a method for producing a retardation film, characterized in that any one of a uniaxial film and a biaxial film. The method of claim 1, The first direction and the second direction is a method for producing a phase difference film, characterized in that the direction perpendicular to each other. Forming a first alignment layer and a second alignment layer on the first substrate and the second substrate and rubbing them, respectively, to perform alignment in the first direction; Arranging a mask on top of the first and second alignment layers oriented in the first direction and irradiating light to align the exposed regions of the first and second alignment layers in a second direction; Forming first and second retardation films on front surfaces of the first and second alignment layers oriented in the first direction and the second direction, respectively; Forming third and fourth alignment layers on the entire surface of the first and second retardation films, respectively, and performing alignment treatment; Bonding the first substrate to the second substrate such that the third alignment layer and the fourth alignment layer face each other; And forming a liquid crystal layer between the bonded first and second substrates. The method of claim 6, The first and second retardation film is a manufacturing method of the liquid crystal display device, characterized in that using any one of a uniaxial film and a biaxial film. The method of claim 6, And the liquid crystal layer is formed by a liquid crystal dropping method or a liquid crystal injection method. The method of claim 6, And the first and second alignment layers are formed on any one of an outer side and an inner side of the first and second substrates. The method of claim 6, Wherein when the first and second alignment layers are formed outside the first and second substrates, the third and fourth alignment layers are formed inside the substrate.