KR20150046800A - Method of fabricating liquid crystal display device - Google Patents

Abstract

The purpose of liquid crystal display device according to the present invention is to improve hardness and adhesive property of a diaphragm by curbing the phenomenon of liquid crystal molecules being trapped inside the diaphragm during its formation through UV-light irradiation. The invention process includes: combining first and second substrates with liquid crystal layer, which has complex photoinitiator, including first and second photoinitiators having different liquid crystal molecules, monomers, wavelength ranges for response, and a dispersant interpolated; irradiating a first UV-light, having a first intensity of illumination, for one hour on a first part with a wavelength filter interpolated to the liquid crystal later and a second part with no wavelength filter; leaving the liquid crystal later for two hours; and forming a diaphragm composed of the monomers on the second part by irradiating a second UV-light, having a second intensity of illumination, the front of the liquid crystal layer for three hours.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of fabricating a liquid crystal display device,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device manufacturing method capable of forming a barrier by curing a monomer of a liquid crystal layer by UV irradiation, minimizing residual monomers, .

Generally, the driving principle of a liquid crystal display device utilizes the optical anisotropy and polarization properties of a liquid crystal. Since the liquid crystal has a long structure, it has a directionality in the arrangement of molecules, and the direction of the molecular arrangement can be controlled by artificially applying an electric field to the liquid crystal.

Therefore, when the molecular alignment direction of the liquid crystal is arbitrarily adjusted, the molecular arrangement of the liquid crystal is changed, and light is refracted in the molecular alignment direction of the liquid crystal by optical anisotropy, so that image information can be expressed.

At present, an active matrix liquid crystal display (AM-LCD: hereinafter referred to as liquid crystal display) in which a thin film transistor and pixel electrodes connected to the thin film transistor are arranged in a matrix manner has excellent resolution and video realization capability, It is attracting attention.

1 is a cross-sectional view of a general liquid crystal display device.

As shown in the figure, a typical liquid crystal display device 1 includes a first substrate 10, a second substrate 80 facing the first substrate 10, a first substrate 10 and a second substrate 80 And a spacer 90 for maintaining a distance between the first and second substrates 10 and 80, that is, a cell gap.

Gate interconnections (not shown) and data interconnections 30 are formed on the first substrate 10 with gate insulating films 16 interposed therebetween and intersecting with each other to define pixel regions. (Not shown), which is connected to the gate and data lines (not shown) and is a switching element, is provided in each of the pixel regions.

Each of the pixel regions is provided with a pixel electrode 50 connected to a drain electrode (not shown) of the thin film transistor (not shown).

On the inner surface of the second substrate 80, a color filter layer 84 composed of red, green, and blue color filter patterns 84a, 84b, and 84c is formed.

A common electrode 86 is formed on the color filter layer 84.

Although not shown, the second substrate 80 is provided with a plurality of pixel electrodes (not shown) formed on the first substrate 10, such as a gate line alehtl, a data line 30, a thin film transistor (not shown) A matrix (not shown) is further formed.

The first and second substrates 10 and 80 having such a configuration face each other so that the pixel electrode 50 and the common electrode 86 face each other. The liquid crystal layer 92 is interposed.

The spacers 90 are in contact with the uppermost layers provided on the first and second substrates 10 and 80 to maintain the distance between the first and second substrates 10 and 80, .

The spacer 90 may be formed on the protective layer 40 or the common electrode 86 by further performing a mask process once during the manufacture of the first substrate 10 or the second substrate 80 to be.

However, a single mask process is required to form the spacer 90, and even if the mask process is performed precisely, an error is generated to cause a height difference of the spacer 90, There arises a problem that the uniformity is lowered.

Therefore, in order to prevent such a problem, the monomer and the photoinitiator are mixed together with the liquid crystal molecules in the liquid crystal layer 92 separately from the spacer 90, and the first and second substrates 140 and 80 are bonded together, A technique of forming the barrier ribs 90 by irradiating light has been proposed.

That is, after the mask process is performed to form the spacers 90 on the first substrate 10 or the second substrate 80 to maintain the initial cell gap, the first substrate 10 and the second substrate 80 (Not shown) in the liquid crystal layer 92 are gathered at specific positions by irradiation of UV light in a state where the first and second substrates 10 and 80 are bonded to each other with the liquid crystal layer 92 interposed therebetween The problem of cell gap nonuniformity can be suppressed by forming the partition wall 90 having a uniform height by being hardened.

However, when the barrier ribs 90 are formed by the irradiation of the monomers (not shown) and the UV light as described above, the adhesion between the barrier ribs 90 and the first and second substrates 10 and 80 is poor, And the liquid crystal molecules are trapped in the barrier ribs 90 because the liquid crystal molecules and the monomers (not shown) are not completely phase-separated from each other, There is a problem that the cell gap can not be maintained due to the weakness of the stiffness of the electrode 90.

On the other hand, when the rigidity of the partition wall 90 is weakened or the adhesive force between the partition wall 90 and the first and second substrates 10 and 80 is weak, defective seal breakage due to liquid crystal sticking occurs.

Particularly, in a flexible liquid crystal display device using a flexible substrate such as a plastic for imparting a bending characteristic to an insulating substrate constituting the base of the first and second substrates 10 and 80 without using a glass substrate, do.

Further, in order to form the partition wall 92 by collecting the monomer (not shown) at a specific position, the UV light must be continuously irradiated for 30 minutes or more, so that the productivity is lowered due to the load of the UV light irradiation device And the monomer (not shown) contained in the liquid crystal layer 92 remains in a portion of the liquid crystal layer 92 corresponding to the display region, and the display quality is degraded.

An object of the present invention is to provide a liquid crystal display device capable of suppressing the phenomenon that liquid crystal molecules are trapped in a barrier rib in the formation of barrier ribs by UV light irradiation to improve rigidity and adhesion of barrier ribs, And it is an object of the present invention to provide a method of manufacturing a liquid crystal display device capable of reducing UV light irradiation time and improving productivity per unit time.

According to an aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device including a liquid crystal molecule, a monomer, a composite photoinitiator including first and second photoinitiating materials having different reaction wavelength bands, The first and second substrates are bonded together with a liquid crystal layer containing a dispersant interposed therebetween; Irradiating the liquid crystal layer with a first portion through a wavelength filter and a first UV light with a first roughness for a second portion without the wavelength filter for a first time; Leaving the liquid crystal layer for a second time; And irradiating the entire surface of the liquid crystal layer left for the second time with a second UV light having a second illuminance for a third time so as to form a partition made of the monomer in the second part.

Wherein the liquid crystal molecule has 80 to 95 wt%, the monomer has 5 to 20 wt%, each of the composite photoinitiator and the dispersant has 1 to 3 wt% based on the monomer, And the second photoinitiator is in the range of 40:60 to 60:40.

The monomer is selected from at least one of a urethane acrylate-based material, a polyester acrylate material, and an epoxy acrylate-based material.

Also, the first photo-initiating material may be at least one selected from the group consisting of 2-Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 1-Hydroxy-cyclohexyl-phenyl-ketone, oxy-phenyl-acetic acid 2- [2-oxo-2- phenyl-acetoxy-ethoxy] -ethyl ester and oxy-phenyl-acetic 2- [2-hydroxy-ethoxy] -ethyl ester ',' 2,4,6-trimethylbenzoyldiphenylphosphine oxide ' Bis (2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H) -pyrimidine -pyrrol-1-yl) -phenyl) titanium, 2-Dimethylamino-2- (4-methylbenzyl) -1- (4-morpholin- Ethanone was prepared from 1- [9-ethyl-6- (2-methylbenzoyl) -9Hcarbazol-3-yl] -, 1- (O- acetyloxime) 2-methyl-1-phenylpropan-1-one, 2,2-dimethoxy-1,2-diphenylethan-1-one, Or the like.

On the other hand, the wavelength filter selectively transmits only UV light of any one of the wavelength ranges of 340 nm to 360 nm.

The first and third times are 3 to 5 minutes each, the second time is 60 to 180 minutes, the first light intensity is 5 to 10 mW / m 2, and the second light intensity is 1000 to 1500 mW / .

The primary and secondary UV light is UV light using a mercury lamp. When the secondary UV light is irradiated, the liquid crystal layer maintains a temperature of 60 ° C or lower.

The liquid crystal molecule has a hydrophilic property, and the monomer has a hydrophobic property.

In addition, it is preferable that, prior to the step of bonding the first and second substrates, a gate and a data line crossing each other on the first substrate and defining a pixel region, a thin film transistor connected to the gate and the data line, Forming a pixel electrode connected to the drain electrode of the thin film transistor; Forming a black matrix on the second substrate corresponding to the boundaries of the pixel regions, and forming a color filter layer in an area surrounded by the black matrix.

At this time, a common electrode alternating with the pixel electrode is formed on the same substrate where the pixel electrode is formed on the first substrate, a common electrode is formed with an insulating layer interposed therebetween above or below the pixel electrode, Or forming an opening for an electrode located above the insulating layer among the common electrodes or forming a common electrode over the color filter layer on the second substrate.

The first and second substrates are each formed by coating a polymer material on the first and second carrier substrates, respectively, having transparent insulating properties, and thus have flexible characteristics. After forming the barrier ribs in the liquid crystal layer, And separating the first and second carrier substrates from the first and second substrates, respectively.

The method of manufacturing a liquid crystal display according to an embodiment of the present invention is a method of forming a barrier rib by irradiating UV light continuously for 30 minutes using one photoinitiator to reduce the UV light irradiation time And the productivity per unit time of the liquid crystal display device is improved.

In the liquid crystal display according to the embodiment of the present invention, sufficient phase separation between the liquid crystal molecules and the monomers is promoted by the phase separation of monomers and the hardening of the monomers, so that the amount of residual monomers in the liquid crystal layer is minimized to 1% The display quality can be improved. Furthermore, since the phenomenon that the liquid crystal molecules are trapped inside the barrier rib by sufficient phase separation can be suppressed, the rigidity of the barrier rib itself is improved.

Further, the phase separation between the liquid crystal molecules and the monomer is smoothly performed, and the hardening of the monomer gathered at a specific part is rapidly performed by the secondary UV light irradiation, thereby increasing the density of the barrier ribs and further improving the patternability of the resulting barrier ribs themselves.

1 is a sectional view of a general liquid crystal display device.
FIGS. 2A to 2J are cross-sectional views illustrating steps of manufacturing a liquid crystal display according to an exemplary embodiment of the present invention.
FIGS. 3A to 3C are cross-sectional views illustrating a method of fabricating a liquid crystal display device according to an embodiment of the present invention (using a composite photoinitiator and a wavelength filter having different reaction wavelength bands) Picture.
4A to 4C are cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to a second comparative example (using a photoinitiator made of a single material, irradiating first and second UV rays without a wavelength filter) Photograph taken in flat form.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

The liquid crystal display device has various driving modes such as a vertical electric field type, a transverse electric field type, and a fringe field switching mode depending on the type of an electric field applied to the liquid crystal layer.

Among these various modes, a fringe field switching mode LCD (FFS-LCD), which has excellent viewing angle characteristics and has a relatively high aperture ratio and transmittance relative to other driving modes, It will be apparent that the present invention can be applied not only to such a fringe field switching mode liquid crystal display device but also to a vertical electric field type and a transverse electric field type liquid crystal display device.

The liquid crystal display device according to the embodiment of the present invention shows a manufacturing method of a liquid crystal display device having a bending characteristic by using a flexible plastic substrate as a base substrate. However, the method may be manufactured using a glass substrate as a base substrate, In this case, in the manufacturing step of the liquid crystal display device according to the embodiment of the present invention to be described later, the first and second plastic substrates are respectively formed on the first and second carrier substrates, and the step of removing and attaching the first and second carrier substrates Except for the step, it will be the same.

2A to 2J are cross-sectional views illustrating one pixel region of a liquid crystal display according to an exemplary embodiment of the present invention. At this time, for convenience of description, a region in which the thin film transistor Tr in the pixel region is formed is defined as an element region TrA.

As shown in FIG. 2A, a first flexible substrate 104 having flexible characteristics is formed by applying a polymeric material, for example, polyimide onto the first carrier substrate 102 and curing it.

At this time, the first carrier substrate 102 may be a glass substrate having a transparent and insulating characteristic, which is used as a base substrate of a general liquid crystal display device.

On the other hand, the first flexible substrate 104 made of polyimide or the like is used for forming a display device capable of bending, but unlike a general glass substrate, itself can not be applied to a manufacturing process of a liquid crystal display device.

In other words, since the first flexible substrate 104 has a flexible characteristic, a large deflection occurs during transportation through a robot arm or the like as a unit process unit for progressing each unit process, It is necessary to align the substrates using alignment pins or the like in order to suppress manufacturing errors in each of the unit processing apparatuses. The first flexible substrate 104, when aligned through the alignment pins, And warping occurs, so that alignment can not be performed.

Therefore, the first flexible substrate 104 is attached to one surface of the first carrier substrate 102 made of glass and is made to be able to be transported and aligned. Then, a general display device manufacturing process is performed, Thereby completing the display device.

Next, as shown in FIG. 2B, a gate and a data line (not shown) 130 for performing a plurality of unit processes on the first flexible substrate 104 and intersecting each other to define a pixel region P, A thin film transistor Tr connected to the gate and the data line (not shown) is formed in the element region TrA in each pixel region P and further the thin film transistor Tr is formed in each pixel region P, A pixel electrode 170 connected to the drain electrode 136 of the pixel electrode 170 and a common electrode 160 positioned between the pixel electrode 170 and the insulating layer 163 are formed.

At this time, for the electrodes located above the pixel electrode 170 and the common electrode 160, a plurality of bar-shaped openings op are provided for each pixel region.

In the drawing, the common electrode 160, the insulating layer 163 and the pixel electrode 170 are sequentially stacked on the protective layer 150, and a plurality of openings op are formed in the pixel electrode 170 As an example.

The thin film transistor Tr provided in each pixel region P is formed of a gate electrode 105, a gate insulating film 110, an active layer 120a of pure amorphous silicon, and an impurity amorphous silicon A semiconductor layer 120 having ohmic contact layers 120b spaced apart from each other and source and drain electrodes 133 and 136 spaced apart from each other.

However, the thin film transistor Tr may have various other configurations.

That is, the thin film transistor Tr is formed of amorphous silicon to form the semiconductor layer 120 having the dual layer structure of the active layer 120a and the ohmic contact layer 120b. However, although not shown in the drawing, An oxide semiconductor layer having a single layer structure may be formed. In this case, an oxide stopper may be further provided on the oxide semiconductor layer and the source and drain electrodes may be spaced apart from the upper portion of the etch stopper.

The thin film transistor (Tr) includes a semiconductor layer formed of a single layer of polysilicon, a gate insulating layer, a gate electrode, and a contact hole exposing the semiconductor layer. And a source electrode and a drain electrode which are in contact with the semiconductor layer of the polysilicon and are spaced apart from each other through the contact hole.

Although the pixel electrode 170 and the common electrode 160 are formed on the first flexible substrate 104 with the insulating layer 163 interposed therebetween, the pixel electrode 170 And the common electrode 170 may have a bar shape in the same layer and alternate with each other or only the pixel electrode 170 may be formed on the first flexible substrate 104, The common electrode 170 may be formed on the second flexible substrate 181 in a subsequent process.

When the liquid crystal display device to be manufactured has a color filter on TFT (COT) structure, although not shown in the drawing, between the thin film transistor Tr and the common electrode (or the pixel electrode 170) A color filter layer may be further formed in which the red, green, and blue color filter patterns are sequentially repeated for each pixel region P before the color filter layer is formed. In this case, A black matrix may also be further formed.

Next, as shown in FIG. 2C, a second flexible substrate 181 having a flexible characteristic is formed by applying a polymeric material, for example, polyimide onto the second carrier substrate 179 and curing it.

Next, as shown in FIG. 2D, a unit process is performed on the second flexible substrate 181 to sequentially form red, green, and blue color filter patterns 184a, 184b, and 184c for each pixel region A color filter layer 184 is formed. At this time, a black matrix (not shown) may be further formed on the second flexible substrate 181 so as to capture the pixel regions corresponding to the boundaries of the pixel regions before the color filter layer 184 is formed.

The color filter layer 184 and the black matrix (not shown) may be omitted in the second flexible substrate 181 if they are formed on the first flexible substrate 104, as described above.

Subsequently, an organic insulating material, for example, photoacrylic, which is transparent, is applied onto the color filter layer 184 to form an overcoat layer 187 over the entire display area.

When the common electrode 160 is omitted on the first flexible substrate 104, a common electrode made of a transparent conductive material is formed in place of the overcoat layer 187 in the second flexible substrate 181 It is possible.

Although not shown in the drawing, before forming the first and second flexible substrates 104 and 181 on the first and second carrier substrates 102 and 179, the first and second carrier substrates A buffer layer (not shown) may be further formed in order to smoothly perform the attachment and detachment of the semiconductor layers 102 and 179.

Detachment of the first and second carrier substrates 102 and 179 from the first and second flexible substrates 104 and 181 may be performed physically. However, in this case, the first and second flexible substrates 104 and 181, 181 may be generated. In order to prevent this, a buffer layer (not shown) for relieving the adhesive force between the carrier substrate 102, 179 and the flexible substrate 104, 181 by generating a gas such as hydrogen at the time of laser beam irradiation And detachment is carried out.

Therefore, in the case where the carrier substrate 102 or 179 is desorbed through the laser beam irradiation, a buffer layer (not shown) is preferentially formed on each of the carrier substrates 102 and 179, and then the buffer layer (not shown) Thereby forming an array element or a color filter layer.

On the other hand, the buffer layer (not shown) is formed by depositing amorphous silicon, for example.

Next, as shown in FIG. 2E, the first flexible substrate 104 formed on the first carrier substrate 102 and the second flexible substrate 181 formed on the first carrier substrate 102 face each other .

Thereafter, a seal pattern (not shown) is formed by dispensing a sealant having an adhesive property along the rim of any one of the first and second flexible substrates 104 and 181, and the seal pattern (not shown) The liquid crystal layer 192 is interposed between the first and second flexible substrates 104 and 181, and then the first and second flexible substrates are joined together.

The liquid crystal layer 140 includes a liquid crystal molecule 242 and a composite photoinitiator (not shown) and a dispersant (not shown) made of the first and second photo initiating materials having different reacting wavelength bands with the monomer 244 do.

The monomer 244 forms a partition wall (290 in FIG. 2J), and it is preferable that the monomer 244 has a hydrophilic property so that phase separation with the liquid crystal molecule 242 is easily generated.

The liquid crystal molecules 242 preferably have a hydrophobic property to facilitate phase separation with the monomer 244.

At this time, the monomer 144 is an acrylate-based material that is a mixture of one or more of urethane acrylate-based materials, polyester acrylate materials, and epoxy acrylate-based materials.

The composite photoinitiator (not shown), which is one of the most characteristic structures in the method of manufacturing a liquid crystal display device according to an embodiment of the present invention, can act as a photo- A first photo-initiating material (not shown) for allowing the cross-linking reaction to progress slowly with respect to the UV light transmitted through the wavelength filter of the 360 nm wavelength band (193 in FIG. 2F) And a second photo-initiating material (not shown) having a characteristic that the curing proceeds rapidly with respect to UV light having an illuminance of about 2 m < 2 >.

The first photo-initiating material (not shown) may be at least one selected from the group consisting of 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide , '2-Hydroxy-1- [4- (2-hydroxyethoxy) phenyl] -2-methyl-1-propanone'

2-hydroxy-ethoxy] -ethyl ester and oxy-phenyl acetic acid 2- [2-hydroxy-ethoxy] Trimethylbenzoyldiphenylphosphine oxide '.

And the second photoinitiating material (not shown)

Bis (2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole) -1-yl) -phenyl) titanium, 2-Dimethylamino-2- (4-methyl-benzyl) -1- (4-morpholin-

'Ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9Hcarbazol-3- yl] -, 1- (O-

2-Methyl-1- [4- (methylthio) phenyl] -2- (4-morpholinyl) -1-propanone,

'2-Hydroxy-2-methyl-1-phenyl-propan-1-

'2,2-Dimethoxy-1,2-diphenylethan-1-one'.

The dispersant (not shown) acts as a binding agent for mixing the liquid crystal molecules 242 and the monomer 244, and may be at least one of BYK187, BYK348, and BYK349, which are water dispersants.

The liquid crystal layer 140 may include 80 to 95% by weight of the liquid crystal molecules 242 and 5 to 20% by weight of the monomer 244, and the composite photoinitiator (not shown) and the dispersant (not shown) Is added in an amount of 1 to 3% by weight relative to the monomer (244).

The first and second photo initiating materials (not shown) constituting the composite photoinitiator (not shown) have a ratio of about 60:40 to 40:60.

In a state where the liquid crystal layer 192 having such a composition ratio is provided, primary UV light is irradiated as shown in FIG. 2F.

At this time, the primary UV light irradiation is performed such that the UV light is directly irradiated to the region where the partition wall (190 of FIG. 2J) is to be formed without the wavelength filter 193, and the wavelength filter 193 So that only UV light having a specific wavelength band is irradiated.

At this time, it is preferable that the wavelength filter 193 pass only UV light having a wavelength range of 340 nm to 360 nm.

The irradiating time of the primary UV light using the wavelength filter 193 for transmitting only the UV light of a specific wavelength range is about 3 to 5 minutes .

The reason why the illuminance is set to about 5 to 10 mW / m 2 when the primary UV light is irradiated is that the phase separation between the liquid crystal molecules 242 and the monomer 244 is slowly and smoothly generated at a later stage.

When the illuminance is higher than 10 mW / m < 2 > at the time of the primary UV light irradiation, the monomer 244 is cured before phase separation occurs, so that a barrier rib having a desired pattern shape is not formed at a desired portion. Therefore, UV light.

On the other hand, when the illuminance of the primary UV light is lower than 5 mW / m 2, since the activation of the first photochromic material is not performed well, phase separation between the liquid crystal molecules 242 and the monomer 244 does not proceed smoothly. Could know.

It is experimentally found that the mercury lamp is preferably used for the irradiation of the primary UV light and that the hardening of the monomer 244 tends not to be performed later when the metal halide lamp is used.

 When the primary UV light using the wavelength filter 193 of this specific wavelength is irradiated on the liquid crystal layer 192, the first photoinitiator (not shown) of the composite photoinitiator (not shown) constituting the liquid crystal layer 192 Is activated.

In addition, the portion where the wavelength filter 193 is not formed is irradiated with UV light having a wavelength range of 340 nm to 360 nm or less, whereby a first photo-initiating material (not shown) and a second photo-initiating material (not shown) The curing process of the monomer 244 proceeds, although it is very slow, by a certain amount of activation.

The second photoinitiator (not shown) reacts rapidly with UV light having an illuminance of about 1000 mW / m < 2 >, and the primary UV light has an illuminance of about 5 to 10 mW / And proceeds very weakly.

On the other hand, after the primary UV light is thus superposed, the liquid crystal panel 101 is allowed to stand at room temperature for 60 to 180 minutes, as shown in Fig. 2G.

Only the first photo initiating material (not shown) is activated in the liquid crystal layer 192 overlapping with the wavelength filter 193 during the primary UV light irradiation to cause phase separation between the liquid crystal molecules 242 of the monomer 244 In the portion irradiated with the primary UV light without the wavelength filter 193, the monomer 244 hardly progresses in cure with phase separation between the liquid crystal molecules 242 of the monomer 244.

Therefore, in the process of being left for 60 to 180 minutes after the irradiation of the primary UV light, the monomer 244 which is cured very slowly with respect to the portion irradiated with the primary UV light without the wavelength filter 193 serves as a seed Thus, the monomer 244 phase-separated from the liquid crystal molecules 242 is gathered around the monomer where curing starts, which is located at a portion where the partition wall (190 in FIG. 2J) is to be formed.

At this time, when the left time of the liquid crystal panel 101 is less than 60 minutes, sufficient phase separation of the liquid crystal molecules 242 and the monomer 244 is not performed, and the phase separated monomer 244 is completely As a result, when the hardening of the monomer 244 proceeds rapidly due to the irradiation of the secondary UV light, there arises a problem that the shape and the rigidity of the partition wall (190 in FIG. 2J) are weakened. (190 in Fig. 2J), it is found that there is almost no difference from the result of the formation of the partition wall (190 in Fig. 2J) for about 180 minutes.

2J). In addition, since the waiting time between the progress of the unit process is utilized, the liquid crystal display device (see FIG. 2J) Of 100). ≪ / RTI >

2H, after the liquid crystal panel 101 is left at room temperature for smooth phase separation between the monomer 244 and the liquid crystal molecules 242, And the second UV light is irradiated without a filter.

At this time, the secondary UV light has an illuminance of 1000 mW to 1500 mW / m < 2 > and is preferably irradiated for 3 to 5 minutes.

The second photoinitiator (not shown) in the composite photoinitiator (not shown) is activated by the second UV light irradiation having such a relatively high roughness, and the activation of the second photoinitiator (not shown) The cross linking between the monomers 244 gathered at the position is generated very quickly, so that the curing by the bond between the monomers 244 progresses rapidly.

At this time, it is preferable that the secondary UV light is also UV light generated by a mercury lamp, and furthermore, the temperature of the liquid crystal layer 192 during the second UV light irradiation having an illuminance of 1000 mW to 1500 mW / So that the temperature is not exceeded.

This is because the characteristics of the liquid crystal molecules 242 are changed when the liquid crystal layer 192 is higher than 60 ° C, which may cause a problem in driving the liquid crystal display device 100 (see FIG. 2J 100).

On the other hand, as described above, the irradiation through the wavelength filter (193 in Fig. 2F) of the primary UV light having a relatively small illuminance, the step of frontal irradiation of the secondary UV light having the predetermined time and the relatively large illuminance The barrier ribs 190 are bonded to the first and second flexible substrates 111 and 181 by the bonding of the liquid crystal molecules 242 and the phase-separated monomers 244 through the liquid crystal layer 192, .

More specifically, the barrier ribs 190 are constituent elements provided on the uppermost layer or the uppermost layer of each of the first and second flexible substrates 111 and 181. For example, on the first flexible substrate 111, 163, and the overcoat layer 187 is formed on the second flexible substrate 181.

The partition wall 190 formed by this method contains a photoinitiator having a single photoinitiator and irradiates the liquid crystal layer including such photoinitiator with UV light continuously for 30 minutes or more only for a specific region, The amount of the remaining monomer in the display region of the liquid crystal layer 192 can be remarkably reduced compared to the method of forming the barrier according to the first comparative example as mentioned in the prior art which simultaneously induces the curing of the monomer, It is possible to suppress the deterioration of the display quality caused by the lowering of the driving of the liquid crystal molecules 242 caused.

Furthermore, as in the first comparative example, when the barrier ribs are formed by continuously irradiating UV light selectively with only one photoinitiator, liquid crystal molecules are trapped inside the barrier ribs due to insufficient phase separation between the liquid crystal molecules and the monomers, There is a problem that the rigidity of the partition wall is deteriorated.

However, according to the method of forming the barrier ribs according to the method of manufacturing a liquid crystal display device according to the embodiment of the present invention, the steps of low-illuminance primary UV light irradiation using the wavelength filter, secondary UV light irradiation at the normal temperature, The phase separation between the monomer 244 and the liquid crystal molecules 242 occurs sufficiently to prevent the liquid crystal molecules 242 from being trapped inside the barrier walls to weaken the rigidity.

The method of forming the barrier ribs 190 in the liquid crystal layer 192 used in the method of manufacturing a liquid crystal display device according to the present invention is a method of forming barrier ribs 190 having two different roughnesses using a composite photoinitiator in which two photo- It is possible to shorten the formation time of the partition 190 by irradiation with UV light to improve the productivity per unit time of the liquid crystal display of the final product and further improve the productivity of the liquid crystal display 192 of the liquid crystal display device 100 It can be reduced compared to the method of manufacturing a liquid crystal display device according to the first comparative example.

On the other hand, in the initial stage of the UV light irradiation characteristic for forming the barrier ribs 190, the reaction proceeds slowly to sufficiently phase-separate the liquid crystal molecules 242 and the monomer 244, The density of the chain at the rate must be increased so that the physical properties of the final formed barrier, that is, the stiffness, can be satisfied.

On the other hand, when the barrier ribs 190 are formed, hardening is required to cause a fast and strong reaction to shorten the time for forming the barrier ribs 190 and increase the rigidity of the barrier ribs 190.

 Therefore, in the production of the liquid crystal display device 100 of FIG. 2J according to the present invention, by using a composite photoinitiator (not shown) made of at least two photo-initiating materials having different reaction wavelength ranges and a wavelength filter (193 in FIG. 2F) At the time of the primary UV light irradiation, only one photo-initiating material is reacted by using the wavelength filter (193 in FIG. 2F) to cause phase separation to occur slowly. At the same time, A portion of the monomer 244 gathered in the region of the liquid crystal layer 192 irradiated on the entire surface of the liquid crystal layer 192 is irradiated with a light without a wavelength filter and a composite photoinitiator ) Are simultaneously reacted, so that the partition 190 can be completely cured quickly.

The barrier ribs 190 formed in the liquid crystal layer 192 do not have problems such as trapping of the liquid crystal molecules 242 in the barrier ribs 190. The barrier ribs 190 are excellent in rigidity, The amount of the monomer 244 to be supplied to the liquid crystal molecules 242 is very fine and thus the driving of the liquid crystal molecules 242 is not affected.

2I, a laser beam is irradiated from the outside of each of the first and second carrier substrates 102 and 179 after the partition 190 is formed in the liquid crystal layer 192, The first and second carrier substrates 102 and 179 are detached from the first and second flexible substrates 104 and 181.

(Not shown) interposed between the first carrier substrate 102 and the first flexible substrate 104 upon irradiation of the laser beam, hydrogen gas is generated from the first carrier substrate 102 and the first flexible substrate 104, The first carrier substrate 102 is well separated from the first carrier substrate 102 without any problem such as peeling off and the second carrier substrate 179 or the full- The second flexible substrate 181 is easily separated from the second flexible substrate 181 by the same operation of the second flexible substrate 181.

Next, by separating the first and second carrier substrates 102 and 179 from the first and second flexible substrates 104 and 181, respectively, as shown in FIG. 2J, the liquid crystal display according to the embodiment of the present invention The device 100 can be completed.

In the method of manufacturing the liquid crystal display device 100 according to the embodiment of the present invention, the liquid crystal display device 110 having the banding characteristics using the flexible substrates 104 and 181 has been described as an example, It will be apparent that the present invention can be similarly applied to the manufacture of a liquid crystal display device using a general glass substrate instead of the second flexible substrate 104 or 181.

That is, in the case of a manufacturing method of a liquid crystal display device using a glass substrate, the steps of forming the first and second flexible substrates on the carrier substrate by forming the barrier ribs by using the same method and omitting the use of only the carrier substrate , And finally omitting the step of detaching the carrier substrate.

3A to 3C and 4A to 4C are cross-sectional views illustrating a method of manufacturing a liquid crystal display device (using a composite photoinitiator and a wavelength filter 193 having different reaction wavelength ranges) according to an embodiment of the present invention and a liquid crystal display device 3A and 4A are photographs showing plan views of barrier ribs according to a step in which barrier ribs are formed in a liquid crystal layer by a manufacturing method (using a photoinitiator made of a single material, irradiation with first and second UV rays without using a wavelength filter) 3B and 4B show the state of the barrier ribs after the irradiation with the primary UV light (illuminance of 8 mW / m 2) for 5 minutes in the present invention and the second comparative example. 3C and 4C show the state of the barrier ribs after irradiation of the secondary UV light (illuminance 1000 mW) for 3 minutes in the present invention and the second comparative example, respectively .

 3A and 4A, it can be seen that the barrier ribs are formed in a lattice form having an aperture of the same rectangular shape as that of the second comparative example (see FIG. 3A) according to the present invention, There is no phenomenon that molecules are trapped.

However, in the case of the second comparative example (see Fig. 4A), it can be seen that the shape of each opening of the lattice does not form a shooting shape, but is a distorted square or circular shape. In the case of forming such an opening, it can be seen that the width of the partition wall is different according to the formation position of the partition wall.

In the second comparative example, the phase separation between the liquid crystal molecules and the monomer is not smoothly performed at this stage, so that liquid crystal molecules are trapped in the respective barrier ribs.

Meanwhile, referring to FIGS. 3B and 4B, after standing for 180 minutes at room temperature, sufficient phase separation is performed between the liquid crystal molecules and the monomer, and thus it can be seen that a lattice-shaped partition wall is formed more clearly.

At this time, it can be seen that the barrier ribs according to the present invention have a uniform width irrespective of the position of the barrier ribs in a lattice form.

However, in the barrier rib according to the second comparative example, the liquid crystal molecules trapped in the barrier rib are largely eliminated at this stage, but the liquid crystal molecules are still trapped at the portion where the barrier rib is crossed, And the shape of the barrier rib according to the present invention is not uniform.

Referring to FIGS. 3C and 4C, after the secondary UV light irradiation, the barrier ribs (see FIG. 3C) manufactured according to the present invention have openings of the same shape over the entire surface and have a width of a relatively constant size have.

On the other hand, it can be seen that the shape of the opening differs according to the formation position of the partition wall according to the second comparative example (see FIG. 4C), and the width also varies according to the position.

It can be seen that a portion where the liquid crystal molecules are trapped in the partition wall is generated.

 On the other hand, when the amount of residual monomers is measured with respect to the liquid crystal layer located at the opening of each partition after the secondary UV light irradiation, the liquid crystal display according to the embodiment of the present invention has an average residual monomer content of 0.56% However, in the case of the liquid crystal display according to the second comparative example, about 1.5% was measured.

As a result of measuring the average molecular weight of the barrier ribs, the average molecular weight of the liquid crystal display device according to the present invention was 20260, but the average molecular weight of the liquid crystal display device according to Comparative Example 2 was 18770.

The average molecular weight of the barrier ribs is closely related to the density and rigidity of the barrier ribs. The high average molecular weight means that the monomers are stably phase-separated from the liquid crystal molecules and are well gathered at specific positions. .

Therefore, in consideration of all these points, it is characterized by irradiating primary UV light through a composite photoinitiator including two or more photoinitiating materials reacting to different wavelength bands according to an embodiment of the present invention and a wavelength filter 193 The manufacturing method of the liquid crystal display device according to the second comparative example is far superior to the liquid crystal display device according to the second comparative example in consideration of the stiffness of the barrier rib, the difference level of the barrier rib width per position, and the residual monomer amount.

Meanwhile, in the method of manufacturing a liquid crystal display device according to an embodiment of the present invention, a method of manufacturing a liquid crystal display device according to a first comparative example, that is, forming a barrier rib by continuously irradiating UV light for 30 minutes using one photoinitiator It is expected to have an effect of improving the productivity per unit time by shortening the UV light irradiation time compared to the method.

The present invention is not limited to the above-described embodiments and modifications, and various modifications may be made without departing from the spirit of the present invention.

102, 179: first and second carrier substrates
104 and 181: first and second flexible substrates
105: gate electrode
110: gate insulating film
120: semiconductor layer
120a, 120b: an active layer and an ohmic contact layer
130: Data wiring
133: source electrode
136: drain electrode
140: Protective layer
160: common electrode
163: Insulation layer
170: pixel electrode
184: Color filter layer
184a, 184b and 184c: red, green and blue color filter patterns
187: Overcoat layer
192: liquid crystal layer
193: Wavelength filter
op: aperture
P: pixel area
Tr: thin film transistor
TrA: device region

Claims (12)

A method of manufacturing a liquid crystal display device, comprising: attaching a first and a second substrate with a liquid crystal layer containing a liquid crystal molecule, a monomer, a composite photoinitiator comprising first and second photoinitiating materials different in reaction wavelength band, and a dispersing agent;
Irradiating the liquid crystal layer with a first portion through a wavelength filter and a first UV light with a first roughness for a second portion without the wavelength filter for a first time;
Leaving the liquid crystal layer for a second time;
Forming a partition made of the monomer in the second portion by irradiating the entire surface for a third time of a second UV light having a second illuminance on the liquid crystal layer left for the second time;
And the second electrode is electrically connected to the second electrode.
The method according to claim 1,
The liquid crystal molecule has 80 to 95% by weight,
The monomer has from 5 to 20% by weight,
Wherein each of the composite photoinitiator and the dispersant has 1 to 3% by weight relative to the monomer,
Wherein the ratio of the first photoinitiator to the second photoinitiator is 40:60 to 60:40.
The method according to claim 1,
Wherein the monomer is selected from at least one of a urethane acrylate-based material, a polyester acrylate material, and an epoxy acrylate-based material.
The method according to claim 1,
The first photoinitiating material may comprise a photoinitiator,
2-Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1'-bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, hydroxyethoxy) phenyl] -2-methyl-1-propanone, 1 -hydroxy-cyclohexyl-
2-hydroxy-ethoxy] -ethyl ester and oxy-phenyl acetic acid 2- [2-hydroxy-ethoxy] Trimethylbenzoyldiphenylphosphine oxide ", and "
The second photoinitiating material may comprise a photo-
Bis (2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole) -1-yl) -phenyl) titanium, 2-Dimethylamino-2- (4-methyl-benzyl) -1- (4-morpholin-
'Ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9Hcarbazol-3- yl] -, 1- (O-
2-Methyl-1- [4- (methylthio) phenyl] -2- (4-morpholinyl) -1-propanone,
'2-Hydroxy-2-methyl-1-phenyl-propan-1-
2,2-dimethoxy-1,2-diphenylethan-1-one '.
The method according to claim 1,
Wherein the wavelength filter selectively transmits only UV light in any one of the wavelength ranges of 340 nm to 360 nm.
The method according to claim 1,
The first and third times are each 3 to 5 minutes,
The second time is from 60 minutes to 180 minutes,
The first roughness is 5 to 10 mW / m < 2 &
And the second illuminance is 1000 to 1500 mW / m < 2 >.
The method according to claim 1,
Wherein the primary and secondary UV light is UV light using a mercury lamp.
The method according to claim 1,
Wherein the liquid crystal layer is maintained at a temperature of 60 占 폚 or less during the secondary UV light irradiation.
The method according to claim 1,
Wherein the liquid crystal molecule has a hydrophilic property and the monomer has a hydrophobic property.
The method according to claim 1,
Before the step of bonding the first and second substrates,
A gate electrode and a data line crossing each other on the first substrate to define a pixel region, a thin film transistor connected to the gate and the data line in the pixel region, and a pixel electrode connected to the drain electrode of the thin film transistor; ;
Forming a black matrix on the second substrate corresponding to a boundary of each pixel region, and forming a color filter layer in an area surrounded by the black matrix.
11. The method of claim 10,
A common electrode alternating with the pixel electrode is formed on the same substrate on which the pixel electrode is formed on the first substrate or a common electrode is formed over or under the pixel electrode with an insulating layer interposed therebetween, Further comprising forming an opening in an electrode of the electrode located above the insulating layer,
Or forming a common electrode over the color filter layer on the second substrate.
The method according to claim 1,
The first and second substrates are each formed by coating a polymer material on first and second carrier substrates, respectively, having transparent insulating properties,
And separating the first and second carrier substrates from each of the first and second substrates after the step of forming the partition walls in the liquid crystal layer.

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