KR101097128B1 - Method of fabricating the liquid crystal display device - Google Patents

Abstract

BACKGROUND ART In a liquid crystal display device, a substrate which is a matrix of an array substrate and a color filter substrate has traditionally used a glass substrate having excellent heat resistance and chemical resistance. However, the glass substrate is expensive, there is a problem that the breakage or breakage easily occurs during the manufacturing process, there is a problem such as easily broken by the impact from the outside even after commercialization.

According to an embodiment of the present invention, an alignment layer is formed at a low temperature by forming a transparent electrode on a lower substrate and a plastic substrate using a glass substrate and a switching element requiring a high temperature process and a color filter layer. And a process of forming a seal pattern using a UV-curable sealant, and improving liquid crystal alignment characteristics by irradiating the entire surface of UV light having a specific energy density and wavelength to produce a liquid crystal display device having excellent display quality. to provide.

Orientation, COT, plastic, rubbing, liquid crystal alignment, UV light

Description

Method of fabricating the liquid crystal display device             

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

2A to 2H are cross-sectional views of a manufacturing process of a first substrate for a liquid crystal display device according to the present invention;

3A to 3B are sectional views of the manufacturing process of the first substrate for a liquid crystal display device according to the present invention;

4 is a process flowchart illustrating manufacturing a liquid crystal panel by bonding a first substrate and a second substrate for a liquid crystal display according to the present invention.

5a to 5g is a liquid crystal panel manufacturing process diagram for manufacturing a liquid crystal display device according to the present invention.

6A and 6B are simplified enlarged views of the surface of the alignment film before rubbing and after rubbing.

FIG. 7 is a diagram illustrating irradiating UV light onto the entire liquid crystal panel. FIG.

8A and 8B are views showing a state in which liquid crystals are aligned after rubbing and before UV light irradiation.                 

9A and 9B illustrate alignment states of liquid crystals after irradiation with UV light having a specific wavelength and energy density.

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

210: first substrate (glass material) 215: (UV curable) seal pattern

220: liquid crystal 230: liquid crystal panel

240: second substrate (plastic material)

290: vacuum bonding machine 291: chamber

292 stage 294 UV lamp

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device using a plastic substrate and a manufacturing method thereof.

In recent years, as the society enters the information age, the display field that processes and displays a large amount of information has been rapidly developed, and recently, the thin film transistor (Thin) having excellent performance of thinning, light weight, and low power consumption has recently been developed. Film Transistor (TFT) type liquid crystal display (TFT-LCD) has been developed to replace the existing cathode ray tube (CRT).                         

The image realization principle of the liquid crystal display device uses the optical anisotropy and polarization property of the liquid crystal. As is well known, the liquid crystal has a thin and long molecular structure and optical anisotropy having an orientation in an array, and when placed in an electric field, the liquid crystal has an orientation of molecular arrangement depending on its size. This change is polarized. The liquid crystal display is an essential component of a liquid crystal panel formed by bonding an array substrate and a color filter substrate formed with pixel electrodes and common electrodes facing each other with the liquid crystal layer interposed therebetween. In addition, it is a non-light emitting device which artificially adjusts the arrangement direction of liquid crystal molecules through the electric field change between these electrodes and displays various images by using the light transmittance which is changed at this time.

Recently, the active matrix type, in which pixels, which are the basic units of image expression, are arranged in a matrix manner, and switching elements are arranged in each pixel, is independently noticed for its excellent resolution and video performance. In addition, thin film transistors (TFTs) are well known as TFT-LCDs (Thin Firm Transistor Liquid Crystal Display Devices).

As shown in FIG. 1, which is an exploded perspective view of a general liquid crystal display, the array substrate 10 and the color filter substrate 20 face to face with the liquid crystal layer 30 interposed therebetween. ) Includes a plurality of gate wires 14 and the data wires 16 arranged vertically and horizontally across the first transparent substrate 12 and its upper surface to define a plurality of pixel regions P. The two wires 14 And the thin film transistor T is provided at an intersection point of the pair 16 and is connected one-to-one with the pixel electrode 18 provided in each pixel region P. FIG.

In addition, the upper color filter substrate 20 facing the second transparent substrate 22 and its rear surface cover the non-display area of the gate line 14, the data line 16, the thin film transistor T, and the like. A grid-like black matrix 25 is formed that borders each pixel region P, and red, green, and red are sequentially arranged to correspond to each pixel region P in the grid of the black matrix 25. A blue color filter layer 26 is formed, and a transparent common electrode 28 is provided over the entirety of the black matrix 25 and the red, green, and blue color filter layers 26.

Meanwhile, in the liquid crystal display device, glass substrates are traditionally used for the first and second transparent substrates 12 and 22, which are the mother substrates of the array substrate 10 and the color filter substrate 20. This is because the glass substrate is excellent in heat resistance and chemical resistance, and also excellent in transparency, so that the substrate itself is not deformed or discolored even by a high temperature process and chemical treatment.

However, the glass substrate having such characteristics is expensive, there is a problem that the breakage or breakage easily occurs during the manufacturing process, there is a problem such as easily broken by the impact from the outside even after commercialization.

In addition, recently, as portable portable devices such as laptops and PDAs are widely used, the emphasis on portability has become a trend of light weight and thinness.

Therefore, as a substitute for the glass substrate, a plastic substrate having a lower cost and flexibility than the glass substrate has been proposed. However, due to the manufacturing characteristics of the liquid crystal display, there are many processes requiring a high temperature of 150 ° C. or higher. There are a lot of difficulties in commercialization.

In the manufacture of the liquid crystal display device, an array process of forming pixels on a large transparent substrate and forming a switching transistor in each pixel, and red, green, and sequential repetitions corresponding to the pixels on another transparent substrate. Complete the liquid crystal display by performing a color filter process for forming a blue color filter and a cell process for forming one liquid crystal panel between liquid crystals between the two substrates by using each of the two substrates. do.

In the above-described process, the array process is performed by using a vacuum device or a device having a chamber in the process of depositing and patterning a metal material, a semiconductor material, an inorganic insulating material, etc., such equipment is a high temperature atmosphere of more than 150 ℃ Since it is necessary to manufacture using a plastic substrate is somewhat unreasonable.

In another example, in the cell process, when the two substrates are bonded to each other, a sealant is printed or dispensed on the edge of one of the two substrates to form a seal pattern, and the two substrates are predetermined. The liquid crystal panel is formed by hardening the seal pattern after all the contact with the seal pattern in the spaced apart state, the hardening of the seal pattern is mainly made by applying a heat of 150 ℃ or more to the substrate.

Therefore, when the liquid crystal display device is manufactured using a plastic substrate having low heat resistance, deformation or discoloration of the plastic substrate may occur during the hardening process of the seal pattern exposed to the cell process, particularly at a high temperature atmosphere, as described above. There is.

In order to solve the above-mentioned problems, the present invention aims to prevent deformation and discoloration of the plastic substrate by omitting a high temperature process by using a sealant used to bond a substrate to form a liquid crystal panel by curing with ultraviolet (UV) light. do.

In addition, it is another object to improve the display quality of the liquid crystal display device by improving the alignment characteristics of the liquid crystal by irradiating the front surface of the substrate with ultraviolet (UV) having a specific energy density for curing the seal pattern.

A method of manufacturing a liquid crystal display device according to an exemplary embodiment of the present invention for achieving the above object is a method of manufacturing a liquid crystal display device having an active area including a plurality of pixel areas, each pixel area on a glass substrate Forming a switching element in the; Forming red, green, and blue color filter patterns which are sequentially repeated on the switching element in each pixel region; Forming a pixel electrode connected to the switching element for each pixel region on the red, green, and blue color filter patterns; Forming a transparent electrode on the front surface of the plastic substrate; Forming first and second alignment layers on the pixel electrode and the transparent electrode, respectively; Performing rubbing on the first and second alignment layers; Forming a UV-curable seal pattern bordering the active region on the rubbed alignment layer of any one of the glass substrate and the plastic substrate; Dropping liquid crystal into an active region inside the seal pattern; Applying silver (Ag) to a substrate other than the substrate on which the seal pattern is formed; Bonding the substrate onto which the liquid crystal is dropped and the substrate on which silver (Ag) is applied to form an appropriate cell gap; Irradiating UV light on the entire surface of the bonded glass substrate or plastic substrate; And cutting the glass substrate and the plastic substrate in the bonded state into active area units.

At this time, the wavelength of the UV light is 250nm to 450nm, the energy density of the UV light is preferably 1J / ㎠ to 2J / ㎠.

The UV light is characterized in that the polarized UV light is irradiated through the polarizing plate.

The forming of the first and second alignment layers may include printing the first and second alignment layers on a plastic substrate and a glass substrate, respectively; And curing the first and second alignment layers formed on the glass substrate and the plastic substrate, respectively, wherein curing of the alignment layer formed on the plastic substrate has a curing temperature of 150 ° C. or less.

The forming of the switching element may include forming a thin film transistor including a semiconductor layer including a gate electrode, a gate insulating layer, and a channel portion, and a source and a drain electrode in each pixel region; Forming a protective layer including the thin film transistor and having a drain contact hole exposing each drain electrode on a front surface thereof; Forming a drain auxiliary electrode contacting the drain electrode through the drain contact hole on the passivation layer. In this case, the pixel electrode is formed in contact with the drain auxiliary electrode.

The method may further include forming a patterned spacer spaced apart from each other on the red, green, and blue color filters exposed to the outside of the pixel electrode.

The method may further include forming a barrier layer by depositing an inorganic insulating material on the top, bottom, or both surfaces of the plastic substrate before forming the transparent electrode.

In addition, the dropping of the liquid crystal is preferably carried out in a vacuum atmosphere.

In addition, the step of bonding the substrate on which the liquid crystal is dropped and the substrate on which silver is applied is performed so that an appropriate cell gap is formed may include forming the substrate on which the liquid crystal is dropped and the coating of silver on the pixel electrode in a vacuum atmosphere. Positioning the transparent electrode so as to face each other; Contacting the two opposing substrates so that the seal pattern contacts both substrates; Changing the atmosphere of vacuum to an atmosphere of atmospheric pressure while the two substrates are in close contact with each other so that the dropped liquid crystal spreads inside the seal pattern.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

The most characteristic feature of the present invention is an array process for forming a thin film transistor, which is a switching element including a large number of high temperature processes of 150 ° C. or more, by using a glass substrate, and adding red, green, and blue color filter patterns to the glass substrate. Further, the substrate corresponding to the substrate on which the switching thin film transistor and the color filter pattern are formed constitutes a liquid crystal display using a plastic substrate. In this case, the common electrode may be formed or omitted on the plastic substrate according to the mode of the liquid crystal display.

Therefore, since the high temperature process does not need to be performed by not forming the switching element or the color filter pattern on the plastic substrate, deformation and discoloration due to the high temperature process does not occur.

However, a process of forming an alignment layer and curing the glass substrate (hereinafter referred to as a first substrate) on which the switching element and the color filter pattern are formed and a plastic substrate (hereinafter referred to as a second substrate) on which the common electrode is formed are commonly performed. In general, the curing process of the alignment film is proceeding to more than 200 ℃, even if the curing time less than 150 ℃ by increasing the curing time relatively experimentally confirmed that there is no problem in performing the role of the alignment film, The first substrate is cured at a high temperature of 200 ° C. or more after the formation of the alignment film, and the second substrate is a plastic substrate material by performing a curing process for a longer time than the time of curing the alignment film on the first substrate below 150 ° C. The second substrate was not exposed to high temperatures.

Hereinafter, a method of manufacturing a liquid crystal display using a plastic substrate according to the present invention will be described in detail with reference to the drawings.

2A to 2H are cross-sectional views illustrating a process of manufacturing a first substrate for a liquid crystal display according to the present invention.

First, as shown in FIG. 2A, a gate wiring in one direction and a gate electrode 112 branched from the gate wiring (not shown) are formed on the transparent glass substrate 110. The gate line and the gate electrode 112 are formed by depositing a metal material on the entire surface of the glass substrate 110 to form a single layer or by forming a double layer by successively depositing different metal materials. After the photoresist is coated on the entire surface of the bilayer, the photoresist is exposed to light using a mask (not shown) having a light transmission region and a blocking region, and the exposed photoresist is developed to develop a specific photoresist pattern ( (Not shown), and simultaneously or continuously etching a single or double layer metal material exposed to the outside of the photoresist pattern (not shown) and remaining on the metal layer of the single layer or double layer structure after the etching. It is formed by striping or ashing the pattern (not shown).

Thereafter, a gate insulating layer 117 is formed on the entire surface of the glass substrate 110 including the gate wiring (not shown) and the gate electrode 112 of the single layer or double layer structure.

Next, as shown in FIG. 2B, pure amorphous silicon (a-Si) and impurity amorphous silicon (n + a-Si) are successively deposited on the gate insulating layer 117, and the photoresist is coated and exposed. The semiconductor layer 120 including the active layer 120a and the ohmic contact layer 120b may be formed to correspond to the gate electrode 112 by performing a mask process including development, etching, and the like.

Next, as shown in FIG. 2C, source and drain electrodes 122 and 124 spaced apart from the upper portion of the semiconductor layer 120 by depositing a metal material on the entire surface of the semiconductor layer 120 and performing a mask process; A data line (not shown) connected to the source electrode 122 and crossing the gate line (not shown) to define the pixel area P is formed.                     

In this case, although the figure shows a single layer, the data line (not shown) and the source and drain electrodes 122 and 124 also have a double layer structure like the gate line (not shown) and the gate electrode 112. You may.

Thereafter, the ohmic contact layer 120b of impurity amorphous silicon is removed by etching the semiconductor layer 120 exposed to the spaced apart region between the source and drain electrodes 122 and 124 to form a channel portion ch.

Next, as shown in FIG. 2D, a protective layer 126 is formed on the entire surface of the glass substrate 110 including the source and drain electrodes 122 and 124, and a mask process is performed to form a lower drain electrode 124. A drain contact hole 127 is formed to partially expose the drain.

Next, as shown in FIG. 2E, a channel material between the source and drain electrodes 122 and 124 is a metal material having excellent shielding power over the passivation layer 126 having the drain contact hole 127. ) And a drain auxiliary electrode 129 contacting the drain electrode 124 through the drain contact hole 127 with the same material as the light blocking film 128.

Next, as shown in FIG. 2F, a red resist is coated on the passivation layer 126, the light blocking film 128, and the drain auxiliary electrode 129, exposed using a mask (not shown), and the red resist is exposed. By developing, the red color filter pattern 130a is repeated at regular intervals, and the green and blue color filter patterns 130b and 130c are formed according to the method of forming the red color filter pattern 130a. The color filter patterns 130a, 130b, and 130c are formed.                     

In this case, each of the red, green, and blue color filter patterns 130a, 130b, and 130c is sequentially repeated for each pixel region P defined by the gate line (not shown) and the data line (not shown) intersecting each other. In some areas corresponding to the drain auxiliary electrode 129, a resist of each color is developed to form a drain auxiliary contact hole 132 to expose the drain auxiliary electrode 129. .

Next, as illustrated in FIG. 2G, a transparent conductive material is deposited on the red, green, and blue color filter patterns 130a, 130b, and 130c on the entire surface, and patterned by performing a mask process to form a lower drain auxiliary electrode 129. The first substrate 109 for an organic material liquid crystal display device is completed by forming a pixel electrode 134 in contact with each other and in each pixel area P.

In this case, as shown in FIG. 2H, a transparent organic insulating material is coated on the pixel electrode 134 on the first substrate 109 and patterned to form a gap between the pixel electrode 134 and the pixel electrode 134. Patterned pattern having a predetermined height and having a predetermined interval corresponding to an area where a gate line (not shown) or a data line (not shown) is formed on the exposed red, green, and blue color filter patterns 130a, 130b, and 130c. The spacer 140 may be further formed.

3A to 3B are cross-sectional views illustrating a manufacturing process of the second substrate for a liquid crystal display according to the present invention.

First, as shown in FIG. 3A, the barrier layer 144 is formed by depositing silicon oxide (SiO ₂ ) or silicon nitride (SiNx), which is an inorganic insulating material, on the top, bottom, or both surfaces of the transparent plastic substrate 140. Form. This is because the plastic substrate 140 has a greater degree of warpage than the glass substrate, thereby forming a barrier layer (not shown) to compensate for the warpage.

Next, as illustrated in FIG. 3B, a transparent conductive material such as indium tin oxide (ITO) is deposited on the entire surface of the plastic substrate 140 on which the barrier layer 144 is formed to form the transparent electrode 147. By forming, the second substrate 139 is completed.

In the manufacturing of the second substrate 139 described above, instead of forming the barrier layer 144, a groove portion for accommodating the plastic substrate is provided to prevent the warpage from occurring, The plastic substrate is attached to a rigid substrate having a warpage of at least about a glass substrate, and conveying is performed in a state in which the plastic substrate is attached to the rigid substrate, without forming the barrier layer for preventing warpage. The transparent electrode may be directly formed on the plastic substrate. At this time, the rigid substrate is removed after bonding the first and second substrates.

Next, FIG. 4 and a part of a cell process flowchart of a cell process for attaching a first glass substrate and a plastic second substrate manufactured as described above through a liquid crystal and then attaching one to complete a liquid crystal display device. A cell process will be described with reference to FIGS. 5A-5D. At this time, for convenience of description, reference numerals have been renumbered 200 times.

First, as shown in FIGS. 4 and 5A, as a first step, a polymer material having a main chain and a side chain on the pixel electrode of the first substrate 210 and the transparent electrode of the second substrate, for example, poly The polyimide is printed using an alignment film coating apparatus 250 including a stage 252, a pan 254, an anilox roll 256, a doctor roll 258, and a dispenser 260, As a second step, the first and second substrates 200 (not shown) on which the alignment layer 212 is printed are exposed to a high temperature for a proper time in a curing apparatus (not shown), so that the first and second substrates 200 (not shown) are exposed. The alignment film 212 of the phase is cured.

In this case, since the first substrate 210 using the glass substrate is not a problem even when exposed to a high temperature of 200 ° C. or more, the alignment film 212 is cured in a high temperature atmosphere of 200 ° C. or more, and a second substrate (not illustrated) of plastic material is used. C) is deformed and deteriorated when the high temperature process is performed at 150 ° C. or higher, thereby curing the alignment layer in an atmosphere of 150 ° C. or less. In this case, the curing time may be longer than the curing time of the alignment film 212 in the first substrate 210, and the curing time of the alignment film (not shown) in the second substrate (not shown).

Next, as shown in FIGS. 4 and 5B, the stages 264 and the rubbing rolls 266 may be formed by the first and second substrates 210 (not shown) on which the alignment layer 212 (not shown) is formed, respectively, as a third step. It moves to a rubbing device 262 comprising a, and one direction rubbing with a rubbing roll 266 wound around a rubbing cloth 268 that rotates the surface of the cured alignment layer 212 (not shown) at a high speed. By advancing to the side chain side of the alignment film 212 (not shown) is aligned in one direction.

6A and 6B which briefly enlarge the alignment film surface before rubbing and after rubbing, before rubbing (see FIG. 6A), branches from the main chain 212a of the alignment film surface before rubbing (see FIG. 6A). Although a plurality of side chains 212b are in an irregular state, it can be seen that the irregularly arranged side chains 212b are arranged in one direction after rubbing (see FIG. 6B).

Next, as shown in FIGS. 4 and 5C, the seal pattern 215 surrounding the active area AA displaying an image using the seal dispensing device 270 on the first substrate 210 as the fourth step. ) And at the same time, a conductive pattern (Ag) coating process for conducting the first and second substrates 210 (not shown) is performed on the second substrate (not shown) to form a conduction pattern (not shown). In this case, the seal pattern 215 formed around the active area AA may be formed as a UV-curable sealant having a property of being cured by UV light irradiation.

In FIG. 4 and FIG. 5C, although the seal pattern is formed on the first substrate and the conduction pattern is formed on the second substrate, the seal pattern is formed on the second substrate and the seal pattern is formed on the first substrate. It is also possible to form a conductive pattern by silver coating.

Next, as illustrated in FIGS. 4 and 5D, the first liquid crystal dropper is formed into a first liquid crystal substrate including a vacuum chamber (not shown), a stage 286, and a liquid crystal dispenser 284 as a fifth step. An active area AA positioned above the stage 286 in a vacuum chamber (not shown) of the device 280 and surrounded by the seal pattern 215 on the first substrate 210 in a vacuum atmosphere. ) Is added dropwise.

Next, as shown in FIGS. 4 and 5E, as a sixth step, the vacuum bonding apparatus 290 including the vacuum chamber 291, the upper and lower stages 292 and 293, and the UV lamp 294 is formed. The first substrate 210 having the appropriate amount of the liquid crystals 220 dropped on the lower stage 292 in the vacuum chamber 291 maintaining the vacuum atmosphere, and the silver (Ag) coating is applied to the upper stage 293. After adsorbing and positioning the second substrate 240, the first and second substrates 210 and 240 are aligned, and then moving the upper stage 293 to the lower stage 292 to the second substrate 240. ) Is in contact with the first substrate 210. In this case, when liquid crystal is dripped on a 2nd board | substrate, the said 2nd board | substrate may be located in a lower stage, and a 1st board | substrate may be located in an upper stage.

Next, as shown in FIGS. 4 and 5F, when the first and second substrates 210 and 240 are brought into contact with each other, the atmosphere in the vacuum chamber 291 in the vacuum state is changed to an atmospheric pressure atmosphere. The inside of the seal pattern 215 between the two substrates 210 and 240 is in a vacuum state, and an atmospheric pressure is formed outside the first and second substrates 210 and 240, that is, inside the chamber, so that the first, 2 The substrates 210 and 240 are brought into close contact with each other. At this time, the liquid crystal 220 dropped into the seal pattern 215 gradually spreads and fills the inside of the seal pattern 215, and at the same time, the seal pattern 215 is also pressed by atmospheric pressure to spread with a predetermined width.

After a certain period of time, the two substrates 210 and 240 are brought into close contact with each other, and more precisely, the patterned spacers (not shown) formed on the seal pattern 215 and the first substrate 210. The two substrates 210 and 240 are supported to maintain an appropriate cell gap.                     

When the seal pattern 215 is spread and the adhesion of the two substrates 210 and 240 is no longer performed and a proper cell gap is formed, as a seventh step, the lower portion of the first substrate 210 or the second substrate 240 is formed. The UV curable seal pattern 215 is cured by irradiating UV light having a suitable energy density on the entire surface of the upper portion or upper / lower portion through the UV lamp 294 at the same time, while simultaneously stabilizing the liquid crystal.

In FIG. 5F, the UV lamp 294 is irradiated from the lower surface of the first substrate 210. However, the UV lamp 294 may be located on the upper surface side of the second substrate, in which case the UV lamp is located. The stage of is made of a transparent material, for example quartz, and passes through the stage to irradiate UV light onto the substrate.

In addition, the irradiation of the UV light is not made in the vacuum chamber (291 of FIG. 5F) of the vacuum bonding apparatus (290 of FIG. 5F), and as shown in FIG. 7, the UV lamp 310 is provided on the upper portion. The liquid crystal panel may be irradiated with the first and second substrates 210 and 240 bonded together without forming a chamber (not shown) and passing through the stage 315.

At this time, the UV light irradiated on the entire surface of the first substrate 210 or the second substrate 240 in the bonded state has a wavelength of 250nm to 450nm, preferably having an energy density of 1 to 2 J / ㎠. In addition, when the UV light is irradiated it may be irradiated with polarized UV light using a polarizing plate (not shown).

Here, the orientation of the liquid crystal will be described for a while.

It is common to align the side chains in the alignment film in one direction by rubbing the alignment film using a polymer material and the alignment film, and to initially align the liquid crystals by the aligned side chains. However, the alignment of the side chains in the alignment layer due to rubbing may cause some of the alignment layer side chains to be misaligned due to the uniformity of the rubbing cloth and the steps of the wirings or the electrodes formed on the substrate. In this case, the degree of alignment of the liquid crystal is dispersed in the aligned direction of the side chains, and the area in which the degree of dispersion of the liquid crystal alignment increases is displayed as spots when displaying an image image.

Therefore, in order to solve the problem of liquid crystal alignment by rubbing, the present invention provides UV light having a specific wavelength and energy density to the entire surface of the substrate including the seal pattern forming region when curing the UV curable seal pattern. Alignment is improving.

8A and 8B are diagrams showing a state in which liquid crystals are aligned before UV light irradiation after rubbing, and FIGS. 9A and 9B are diagrams showing alignment states of liquid crystals after irradiation with UV light having a specific wavelength and energy density.

As shown in FIGS. 8A and 8B, before the UV light irradiation, the liquid crystals are aligned along the rubbing direction, that is, along the direction in which the side chains of the alignment layer are aligned, but the direction of the liquid crystal director is slightly different based on the rubbing direction. It can be seen that the inclination angle formed between the surface of the alignment film of the liquid crystal and the liquid crystal director is also irregularly aligned. When an image is displayed by applying a voltage to the liquid crystal display having such a state, unevenness occurs due to uneven alignment of liquid crystals.

On the other hand, referring to Figures 9a and 9b showing the alignment state of the liquid crystal after the UV light irradiation, by irradiating the UV light having a specific energy density and wavelength to the substrate containing the liquid crystal including the alignment film by the irradiated UV light The side chains in the alignment film react to increase the arrangement, and the alignment regulating force is also increased, whereby the alignment of the liquid crystal can be improved as a whole.

Thus, as shown in the figure, the direction of the liquid crystal director is substantially coincident with the rubbing direction, and the inclination angle between the alignment film surface and the liquid crystal director also induces a constant alignment of the liquid crystal, as described above. The excellent liquid crystal display device having improved uniformity has excellent display quality without spots due to misalignment when voltage is applied.

The process after the seal pattern will be described again for the cell process for forming the liquid crystal display.

As shown in FIG. 4 and FIG. 5G, as the eighth step, the seal pattern is cured by curing the seal pattern 215, thereby forming the first and second substrates 210 and 240 forming one liquid crystal panel. By cutting using a cutting wheel or the like along the outer side of 215, the liquid crystal panel in a disc state is separated into a unit liquid crystal panel having one active pattern AA.

When the disc liquid crystal panel 230 including a plurality of active patterns is cut in this way, since the cut surface is very sharp, the unit liquid crystal panel is completed by processing it so as not to be sharp.

Subsequently, the completed unit panel performs a module process of attaching a PCB and a backlight unit to complete a liquid crystal display device.

The liquid crystal display and the manufacturing method of the COT structure according to the present invention comprise an array and a color filter forming process requiring a high temperature of 150 ° C. or higher on a lower substrate using a glass substrate, and the upper substrate has a weaker heat resistance and chemical resistance than a glass substrate. It is possible to reduce the manufacturing cost by forming only a transparent electrode and an alignment layer that can be formed by a low temperature process using a plastic substrate and combining the two substrates together to form a liquid crystal panel, and using a light plastic substrate instead of a heavy glass substrate. It is effective to realize the product.

In addition, by forming a seal pattern as a UV-curable sealant, and irradiated with UV light on the entire surface during curing of the seal pattern, there is an effect of finally improving the display quality by improving the alignment of the liquid crystal.

Claims (12)

In the method of manufacturing a liquid crystal display device in which an active region including a plurality of pixel regions is defined, Forming a switching element in each pixel region on the glass substrate; Forming red, green, and blue color filter patterns which are sequentially repeated on the switching element in each pixel region; Forming a pixel electrode connected to the switching element for each pixel region on the red, green, and blue color filter patterns; Forming a transparent electrode on the front surface of the plastic substrate; Forming first and second alignment layers on the pixel electrode and the transparent electrode, respectively; Performing rubbing on the first and second alignment layers; Forming a UV-curable seal pattern bordering the active region on the rubbed alignment layer of any one of the glass substrate and the plastic substrate; Dropping liquid crystal into an active region inside the seal pattern; Applying silver (Ag) to a substrate other than the substrate on which the seal pattern is formed; Bonding the substrate onto which the liquid crystal is dropped and the substrate on which silver (Ag) is applied to form an appropriate cell gap; Irradiating UV light on the entire surface of the bonded glass substrate or plastic substrate; Cutting the bonded glass and plastic substrates into active area units And forming a barrier layer by depositing an inorganic insulating material on the top, bottom, or both surfaces of the plastic substrate before forming the transparent electrode. The method of claim 1, The wavelength of the UV light is 250nm to 450nm manufacturing method of the liquid crystal display device. The method of claim 1, The energy density of the UV light is a manufacturing method of the liquid crystal display device 1J / ㎠ to 2J / ㎠. The method according to any one of claims 1 to 3, The irradiation of the UV light is a manufacturing method of the liquid crystal display device characterized in that the polarized UV light is irradiated through the polarizing plate. The method of claim 1, Forming the first and second alignment layers Printing the first and second alignment layers on the plastic substrate and the glass substrate, respectively; Curing the first and second alignment layers formed on the glass substrate and the plastic substrate, respectively; Method of manufacturing a liquid crystal display device comprising a. The method of claim 5, The hardening of the alignment film formed on the said plastic substrate is a manufacturing method of the liquid crystal display device whose hardening temperature is 150 degrees C or less. The method of claim 1, Forming the switching element Forming a thin film transistor including a semiconductor layer including a gate electrode, a gate insulating film, and a channel portion in each pixel area, and a source and a drain electrode; Forming a protective layer including the thin film transistor and having a drain contact hole exposing each drain electrode on a front surface thereof; Forming a drain auxiliary electrode on the protective layer and in contact with the drain electrode through the drain contact hole; Method of manufacturing a liquid crystal display device comprising a. The method of claim 7, wherein And the pixel electrode is in contact with the drain auxiliary electrode. The method of claim 1, And forming a patterned spacer spaced apart from each other on the red, green, and blue color filters exposed to the outside of the pixel electrode. delete The method of claim 1, The dropping of the liquid crystal may be performed in a vacuum atmosphere. The method of claim 1, Bonding the substrate onto which the liquid crystal is dropped and the substrate on which silver (Ag) is applied to form an appropriate cell gap; Positioning a substrate on which the liquid crystal is dropped and a substrate on which silver (Ag) is applied in a vacuum atmosphere such that the pixel electrode and the transparent electrode face each other; Contacting the two opposing substrates so that the seal pattern contacts both substrates; Changing the atmosphere of vacuum to atmospheric pressure while the two substrates are in close contact with each other so that the dropped liquid crystal spreads inside the seal pattern; Method of manufacturing a liquid crystal display device comprising a.

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