KR102512638B1 - Method of fabricating liquid crystal display device - Google Patents

Abstract

The present invention relates to a liquid crystal display device, and more particularly, to a manufacturing method for a liquid crystal display device having an improved contrast ratio.
A feature of the present invention is to further position the second liquid crystal panel below the first liquid crystal panel, thereby adjusting the transmittance of light supplied from the backlight through the second liquid crystal panel and supplying the light to the first liquid crystal panel, thereby realizing the first liquid crystal panel. This will improve the contrast ratio of the image.
In particular, as the coated polarizer is positioned between the first liquid crystal panel and the second liquid crystal panel, transmission and blocking of light can be realized more clearly, thereby improving overall transmission efficiency of the liquid crystal display.
In addition, process efficiency is improved by simultaneously rubbing the first alignment layer and the fifth alignment layer positioned on both sides of the first substrate through a photo alignment method.

Description

Manufacturing method of liquid crystal display device {Method of fabricating liquid crystal display device}

The present invention relates to a liquid crystal display device, and more particularly, to a manufacturing method for a liquid crystal display device having an improved contrast ratio.

The liquid crystal display device (LCD), which is advantageous for displaying moving images and has a large contrast ratio, is actively used in TVs and monitors. It shows the principle of image realization by .

Such a liquid crystal display device has as an essential component a liquid crystal panel bonded by interposing a liquid crystal layer between two parallel substrates, and realizes a difference in transmittance by changing the arrangement direction of liquid crystal molecules with an electric field in the liquid crystal panel. do.

Recently, vertical electric field liquid crystal display devices that drive liquid crystals with an electric field formed from up and down are widely used because of their excellent resolution and ability to realize moving images, but liquid crystal display devices driven by electric fields applied up and down have poor viewing angle characteristics.

Accordingly, various methods have been proposed to overcome the disadvantage of a narrow viewing angle, and among them, a method of driving a liquid crystal by a horizontal electric field in which a horizontal electric field is formed is attracting attention.

1 is a cross-sectional view of a general transversal electric field type liquid crystal display.

As shown, the lower substrate 1, which is an array substrate, and the upper substrate 3, which is a color filter substrate, are spaced apart from each other and face each other, and a liquid crystal layer 5 is interposed between the upper and lower substrates 1 and 3. there is.

On the lower substrate 1, the pixel electrode 27 and the common electrode 25 are formed on the same plane, and the liquid crystal layer 5 generates a horizontal electric field (L) by the pixel electrode 27 and the common electrode 25. is operated by

A thin film transistor (TFT) is formed in each pixel area defined by a gate wiring (not shown) and a data wiring (not shown) on the lower substrate 1 of the transverse electric field type liquid crystal display device, and the upper substrate (3), a color filter layer (not shown) and a black matrix (not shown) are formed, and the lower substrate 1 and the upper substrate 3 are bonded by a sealing material (not shown) such as epoxy resin.

And, in order to adjust the alignment of the liquid crystal layer 5, a lower alignment layer 11 and an upper alignment layer 13 are provided on the lower substrate 1 and the upper substrate 3 facing each other with the liquid crystal layer 5 interposed therebetween. do.

On the other hand, such a horizontal electric field liquid crystal display device has a problem of showing a low contrast ratio (CR) due to leakage of light when displaying a black state, despite implementing a wide viewing angle.

Normally, the vertical field type liquid crystal display has a white to black contrast ratio of 6000:1, but the horizontal field type liquid crystal display has a level of 1600:1 or 1900:1, which is very low compared to the vertical field type liquid crystal display. has a contrast ratio.

Here, the contrast of an image generally means the difference between light and dark areas in an image, that is, the size of the contrast ratio. The higher the contrast ratio, the higher the contrast of the image. An image with high contrast can be said to have excellent sharpness because the difference between light and dark areas in the image is clear.

Therefore, there is an urgent need for research to improve the contrast ratio of the current horizontal electric field type liquid crystal display device to realize a clear picture quality.

SUMMARY OF THE INVENTION The present invention is to solve the above problems, and to provide a transverse electric field type liquid crystal display having an improved contrast ratio.

In order to achieve the object as described above, the present invention comprises the steps of coating a first alignment material layer on the inner surface of a first substrate, and coating a second alignment material layer on the outer surface of the first substrate; and a photo-alignment step of irradiating UV light from an upper portion of the first substrate, and in the photo-alignment step, the first and second alignment material layers are aligned at the same time, and the first and second alignment material layers are respectively aligned on both sides of the first substrate. A method of manufacturing a liquid crystal display device having a second alignment layer is provided.

As described above, according to the present invention, by further positioning the second liquid crystal panel below the first liquid crystal panel, by adjusting the transmittance of light supplied from the backlight through the second liquid crystal panel and supplying it to the first liquid crystal panel, 1 It has an effect of improving the contrast ratio of an image implemented in a liquid crystal panel.

In particular, as the coated polarizer is positioned between the first liquid crystal panel and the second liquid crystal panel, transmission and blocking of light can be realized more clearly, thereby improving the overall transmission efficiency of the liquid crystal display.

In addition, by simultaneously rubbing the first alignment layer and the fifth alignment layer positioned on both sides of the first substrate through a photo alignment method, process efficiency is improved.

1 is a cross-sectional view of a general transversal electric field type liquid crystal display;
2 is a schematic cross-sectional view of a liquid crystal display device according to an embodiment of the present invention.
3 is an enlarged cross-sectional view of area A of FIG. 2;
4 is a process flow chart illustrating a manufacturing method of a liquid crystal display according to an embodiment of the present invention according to a process sequence;
5 is a process flow diagram embodying the cell process of FIG. 4;
Figure 6 is an experimental result of measuring the transmittance of the glass substrate according to the ultraviolet wavelength range.
7 is an experimental result of evaluating the alignment afterimage for each exposure energy of the alignment layer.

The present invention comprises the steps of coating a first alignment material layer on the inner surface of a first substrate, coating a second alignment material layer on the outer surface of the first substrate, and irradiating UV from the top of the first substrate. In the optical alignment step, the first and second alignment material layers are simultaneously aligned, and first and second alignment layers are provided on both sides of the first substrate, respectively. A manufacturing method is provided.

In this case, the first substrate is made of glass, the UV has a wavelength of 310 nm to 365 nm, and a coating type polarization layer is formed on the second alignment layer.

and positioning a second substrate including a first liquid crystal layer and a third alignment layer on top of the first alignment layer, wherein the first liquid crystal layer, the second substrate and the first liquid crystal layer Forming a panel, including forming a fifth alignment layer on top of the coated polarizing layer, and positioning a third substrate including a second liquid crystal layer and a fourth alignment layer on top of the fifth alignment layer, , the first substrate, the third substrate and the second liquid crystal layer form a second liquid crystal panel.

In this case, positioning a first polarizing plate having a polarization axis in a first direction outside the second substrate, and positioning a second polarizing plate having a polarization axis in the first direction outside the third substrate, The coating-type polarization layer has a polarization axis in a second direction perpendicular to the first direction, and positioning a backlight below the second liquid crystal panel, wherein the second liquid crystal panel receives light emitted from the backlight. is controlled and supplied to the first liquid crystal panel.

And, before forming the fifth alignment layer with the coated polarization layer, a step of providing a planarization layer on the coated polarization layer is further included.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

FIG. 2 is a schematic cross-sectional view of a liquid crystal display device according to an exemplary embodiment of the present invention, and FIG. 3 is an enlarged cross-sectional view of area A of FIG. 2 .

As shown, the liquid crystal display device 100 according to an embodiment of the present invention largely includes a first liquid crystal panel 110 displaying an image, a second liquid crystal panel 120 acting as a shutter, and light It is composed of a backlight 130 to supply.

Looking at each of these in more detail, first, the first liquid crystal panel 110 includes first and second substrates 101 and 102 and a first liquid crystal layer 103 interposed between the two substrates 101 and 102. do.

At this time, on the inner surface of the first substrate 101 facing the second substrate 102, a plurality of gate wires (not shown) arranged in parallel and spaced apart at predetermined intervals intersect with the gate wires (not shown) to form a first pixel region. A data wire (not shown) defining (1-P) is configured.

In addition, a first thin film transistor 1-DTr is formed at an intersection of a gate line (not shown) and a data line (not shown) of each first pixel region 1-P, and each first pixel region 1 -P) is connected to the first thin film transistor (1-DTr) through the first drain contact hole 109a, and a plurality of first pixel electrodes 111 made of a transparent conductive material are formed.

Here, the first thin film transistor (1-DTr) includes a first gate electrode 104, a first gate insulating layer 105, a first semiconductor layer 106, and first source and first drain electrodes 107 and 108. made up of

At this time, the first pixel electrodes 111 are separated into a plurality in a bar shape, spaced apart from each other, and are formed in each first pixel region 1-P. In addition, a common wiring (not shown) is formed on the same layer parallel to the gate wiring (not shown), electrically connected to the common wiring (not shown), and a plurality of first pixels in each first pixel region 1-P. A plurality of first common electrodes 113 alternately spaced apart from the electrodes 111 are formed.

Meanwhile, as another example, the first pixel electrode 111 may be formed in a plate shape for each first pixel region 1-P. In this case, a portion of the first pixel electrode 111 may be overlapped with a gate wiring (not shown) to form a storage capacitor.

The first liquid crystal panel 110 realizes a wide viewing angle as an electric field is formed horizontally due to the first pixel electrode 111 and the first common electrode 113 formed on the first substrate 101. .

A first black matrix 115 having openings corresponding to the first pixel regions 1-P is formed on the inner side of the second substrate 102 facing the first substrate 101, and these openings are Correspondingly, a color filter layer 116 including red, green, and blue color filters sequentially and repeatedly arranged is formed.

A first planarization layer 117 is formed on the color filter layer 116 .

In addition, the first and third alignment films 160 and 170, which determine the initial molecular alignment direction of the liquid crystal, are interposed between the two substrates 101 and 102 and the first liquid crystal layer 103, and the first substrate 101 ) and the second substrate 102, seal patterns (not shown) are formed along the edges of both substrates 101 and 102 to prevent leakage of the first liquid crystal layer 103 filled between them.

Therefore, the first liquid crystal panel 110 is selected for each gate wiring (not shown) by the on/off signal of the first thin film transistor (1-DTr) scanned and transferred to the gate wiring (not shown). When the first thin film transistor (1-DTr) is turned on, the image signal of the data line (not shown) is transferred to the corresponding first pixel electrode 111, and the first pixel electrode 111 and the second 1 The arrangement direction of the liquid crystal molecules of the first liquid crystal layer 103 is changed by the electric field between the common electrodes 113, resulting in a difference in transmittance.

That is, the first and third alignment layers 160 and 170 of the first liquid crystal panel 110 are rubbed in the vertical direction (90 degrees) when viewed from the front of the panel, and thus the first pixel electrode 111 ) and the first common electrode 113 in a state where no voltage is applied, the plurality of liquid crystal molecules of the first liquid crystal layer 103 are arranged so that their long axes are parallel to the vertical direction (90 degrees) when viewed from the front of the panel. .

At this time, the plurality of liquid crystal molecules are parallel to the ground and parallel to the bar-shaped longitudinal direction of the first pixel electrode 111 and the first common electrode 113 .

In addition, in a state in which voltage is applied to the first pixel electrode 111 and the first common electrode 113, the plurality of liquid crystal molecules of the first liquid crystal layer 103 rotate along the horizontal electric field so that the long axis is at the front of the panel. When viewed, they are rearranged so as to be parallel to the left and right direction (0 degree), parallel to the ground, and perpendicular to the longitudinal direction of the bar shape of the first pixel electrode 111 and the first common electrode 113.

Accordingly, the arrangement direction of the plurality of liquid crystal molecules changes depending on whether voltage is applied or not, and light emitted from the backlight 130 is transmitted or blocked, so that the first liquid crystal panel 110 implements an image.

A second liquid crystal panel 120 is positioned outside the first substrate 101 of the first liquid crystal panel 110, and the second liquid crystal panel 120 faces the outer surface of the first substrate 101. It includes a third substrate 121 and a second liquid crystal layer 123 interposed between the outer surface of the first substrate 101 of the first liquid crystal panel 110 and the third substrate 121 .

Here, on the third substrate 121, a plurality of gate wires (not shown) spaced apart from each other in parallel and data wires (not shown) intersecting the gate wires (not shown) to define the second pixel region 2-P. city) is composed of

At this time, the second pixel region 2-P defined by the crossing of the gate wiring (not shown) and the data wiring (not shown) in the second liquid crystal panel 120 is the first pixel region 2-P defined in the first liquid crystal panel 110. It can be formed larger than the pixel area 1-P. As the first liquid crystal panel 110 actually implements an image, the smaller the first pixel area 1-P is, the clearer the image can be realized. Therefore, it is preferable that the first pixel region 1-P of the first liquid crystal panel 110 be small and highly defined.

However, since the second liquid crystal panel 120 only serves as a shutter to control the light supplied from the backlight 130 to the first liquid crystal panel 110, the second pixel area 2 of the second liquid crystal panel 120 Since the size or number of -P) is not important, it is preferable to make the second pixel region 2-P of the second liquid crystal panel 120 large in order to form the second liquid crystal panel 120 more easily.

Also, second thin film transistors 2-DTr are formed at intersections of gate wires (not shown) and data wires (not shown) of each second pixel region 2-P of the second liquid crystal panel 120. , In each second pixel region 2-P, a plurality of second pixel electrodes 125 made of a transparent conductive material and connected to the second thin film transistor 2-DTr through the second drain contact hole 129a are formed. has been

Although not shown, the second thin film transistor 2-DTr includes a second gate electrode, a second gate insulating layer, a second semiconductor layer, a second source, and a second drain electrode.

At this time, the second pixel electrodes 125 are separated into a plurality in a bar shape and spaced apart from each other, and are formed in each second pixel region 2-P. In addition, a common wiring (not shown) is formed on the same layer parallel to the gate wiring (not shown), electrically connected to the common wiring (not shown), and a plurality of second pixels in each second pixel region 2-P. A plurality of second common electrodes 127 alternately spaced apart from the electrodes 125 are formed.

On the outer surface of the first substrate 101 of the first liquid crystal panel 110 facing the third substrate 121, a second black matrix 128 having an opening corresponding to the second pixel region 2-P is formed. is formed, and a second planarization layer (not shown) is formed on the second black matrix 128 .

In addition, at the boundary between the surfaces of the third substrate 121 and the first substrate 101 facing each other and the second liquid crystal layer 123, fourth and fifth alignment films (which determine the initial molecular alignment direction of the liquid crystal) 180 and 190) are interposed, and the second liquid crystal layer 123 filled between the third substrate 121 and the first substrate 101 is prevented from leaking by failing to turn along the edges of both substrates 121 and 101. (seal pattern: not shown) is formed.

The fourth and fifth alignment layers 180 and 190 of the second liquid crystal panel 120 are also rubbed in the vertical direction (90 degrees) when viewed from the front of the panel, and thus the second pixel electrode 125 and In a state where no voltage is applied to the second common electrode 127, the long axis (optical axis) of the plurality of liquid crystal molecules of the second liquid crystal layer 123 is the same as that of the second pixel electrode 125 and the second common electrode 127. They are arranged parallel to the longitudinal direction of the shape.

And, in a state in which voltage is applied to the second pixel electrode 125 and the second common electrode 127, a plurality of liquid crystal molecules of the second liquid crystal layer 123 rotate along the horizontal electric field so that the long axis is at the front of the panel. When viewed, they are rearranged so as to be parallel to the left and right direction (0 degrees), parallel to the ground, and perpendicular to the longitudinal direction of the bars of the second pixel electrode 125 and the second common electrode 127.

And, the first polarizer 140 is attached to the outer surface of the third substrate 121 of the second liquid crystal panel 120, and the outer surface of the second substrate 102 of the first liquid crystal panel 110 A second polarizing plate 150 is attached, and a third polarizing plate 200 is interposed between the first liquid crystal panel 110 and the second liquid crystal panel 120 .

Here, the first and second polarizers 140 and 150 have the same first polarization axis, and the third polarizer 200 interposed between the first and second liquid crystal panels 110 and 120 is the first and second polarizers. It has a second polarization axis perpendicular to the first polarization axis of (140, 150).

At this time, although not shown, the first and second polarizing plates 140 and 150 each consist of a first polarizing layer having a polarization axis in a first direction that changes the polarization characteristics of light, a first base film, and a second base film. The first polarization layer is positioned between the first and second base films and protected and supported by the first and second base films.

In addition, the first polarization layers of the first and second polarizers 140 and 150 actually play a role in determining polarization characteristics, and each is made of iodine (I) or dye-stained poly-vinyl alcohol (PVA). It may be formed by stretching.

And, as shown in FIG. 3, the third polarizing plate 200 positioned between the first and second liquid crystal panels 110 and 120 is a second alignment layer 210 formed on the outer surface of the first substrate 101. and a coated polarization layer 220 positioned above the second alignment layer 210 and including a second polarization axis in a second direction perpendicular to the first direction, and a third planarization positioned above the coated polarization layer 220. Layer 230 is included.

A fifth alignment layer 190 is positioned above the third planarization layer 230 to guide the alignment direction of liquid crystal molecules of the second liquid crystal layer 123 .

That is, the third polarizer 200 positioned between the first liquid crystal panel 110 and the second liquid crystal panel 120 is a coating type polarizer formed by a coating method, compared to the first and second polarizers 140 and 150. It can have a thin thickness, has excellent heat resistance and light resistance, and has low processing cost due to a simple coating process.

In particular, since the coated polarizer 200 implements the polarization axis through the arrangement of the liquid crystal molecules 221, the distortion of the polarization axis is minimized compared to the first and second polarizers 140 and 150 formed by stretching iodine or dye. Therefore, transmission and blocking of light can be implemented more clearly.

In the third polarizing plate 200, a coating type polarizing layer 220 including a liquid crystal material arranged along the alignment direction of the alignment layer is positioned on the second alignment layer rubbed along the second direction, so that the second polarization layer in the second direction is formed. have a polarization axis.

The liquid crystal material of the coated polarization layer 220 is obtained by mixing guest R, G, and B dyes 223a, 223b, and 223c with liquid crystal molecules 221 as a host, depending on the alignment direction of the second alignment layer 210. When the liquid crystal molecules 221 are arranged, the R, G, and B dyes 223a, 223b, and 223c are arranged together to absorb light parallel to the alignment direction (absorption direction) of the dyes and transmit light perpendicular to the alignment direction (absorption direction) of the dyes to polarize the light. will make

In addition, a backlight 130 for supplying light to the first and second liquid crystal panels 110 and 120 is provided under the third substrate 121 of the liquid crystal display device 100. The light of a light source (not shown) emitted from one side of the rear side of the substrate 121 is refracted by a light guide plate (not shown) to be incident to the first and second liquid crystal panels 110 and 120 .

The backlight 130 is divided into a side type and a direct type according to the location of a light source (not shown) emitting light. The side light type is provided on the first and second liquid crystal panels 110 and 120 For the first and second liquid crystal panels 110 and 120, the light of a light source (not shown) emitted from one side of the rear side thereof is refracted by a separate light guide plate (not shown) and emitted toward the first and second liquid crystal panels 110 and 120. And a plurality of light sources (not shown) are directly disposed on the rear surface of the second liquid crystal panels 110 and 120 to cause light to be incident.

The present invention can use either of these two.

At this time, as the light source (not shown), a fluorescent lamp such as a cold cathode fluorescent lamp or an external electrode fluorescent lamp may be used. Alternatively, a light emitting diode lamp may be used as a lamp other than the fluorescent lamp.

The liquid crystal display device 100 according to this embodiment of the present invention adjusts the transmittance of light supplied from the backlight 130 through the second liquid crystal panel 120 and supplies it to the first liquid crystal panel 110, so that the first liquid crystal The contrast ratio of an image implemented on the panel 110 is improved.

That is, when the liquid crystal display device 100 wants to display a black state, the second and third polarizers 150 and 200 positioned on both sides of the first liquid crystal panel 110 and the first liquid crystal panel ( 110) blocks the light provided from the backlight 130 through the first liquid crystal layer 103. At this time, the liquid crystal display device 100 according to the embodiment of the present invention Since the light provided from the backlight 130 is once again blocked through the polarizer 140 and the second liquid crystal layer 123, a more perfect black state is displayed.

Accordingly, the contrast ratio of an image implemented on the first liquid crystal panel 110 is improved.

In particular, as the coated polarizer 200 is positioned between the first liquid crystal panel 110 and the second liquid crystal panel 120, transmission and blocking of light can be realized more clearly, thereby reducing overall transmission of the liquid crystal display device 100. will improve efficiency.

Meanwhile, in the liquid crystal display device 100 according to an embodiment of the present invention, as the third polarizer 200 interposed between the first liquid crystal panel 110 and the second liquid crystal panel 120 is made of a coated polarizer, The first alignment layer 160 for inducing the alignment direction of the liquid crystal molecules of the first liquid crystal layer 103 is positioned on the inner side of the first substrate 101, and the third alignment layer 160 is positioned on the outer side of the first substrate 101. A second alignment layer 210 is positioned to guide the alignment direction of liquid crystal molecules of the coated polarization layer 220 of the polarizer 200 .

At this time, the liquid crystal display device 100 according to the embodiment of the present invention connects the first alignment layer 160 and the second alignment layer 210 positioned on both sides of the first substrate 101 through a photo alignment method. By simultaneously rubbing, the efficiency of the process is improved.

Accordingly, a more detailed description will be made with reference to FIG. 4 .

4 is a process flow chart illustrating a manufacturing method of a liquid crystal display according to an embodiment of the present invention according to the process sequence, and FIG. 5 is a process flow chart embodying the cell process of FIG. 4, which will be described with reference to FIG. 2. .

6 is an experimental result of measuring the transmittance of a glass substrate according to an ultraviolet wavelength range, and FIG. 7 is an experimental result of evaluating an afterimage of an alignment layer according to exposure energy.

As shown in FIG. 4, the liquid crystal display device (100 in FIG. 2) according to an embodiment of the present invention includes first and second array processes (st100 and st200), a color filter process (st300), and a cell process (st400). ), manufactured through a module process (st500).

In the first array process st100, a first thin film transistor (1 in FIG. 2) is placed on the first substrate (101 in FIG. 2) constituting the first liquid crystal panel (110 in FIG. 2) through a photolithographic process. -DTr) of the first gate electrode (104 in FIG. 2), the first gate insulating layer (105 in FIG. 2), the first semiconductor layer (106 in FIG. 2), the first source electrode (107 in FIG. 2), 1 A drain electrode (108 in FIG. 2) is formed, and a first passivation layer (109 in FIG. 2) and a first pixel electrode (111 in FIG. 2) are formed above the first thin film transistor (1-DTr in FIG. 2). 1 A common electrode (113 in FIG. 2) is formed.

In the second array process (st200), a second thin film transistor (FIG. 2) is placed on the third substrate (121 in FIG. 2) constituting the second liquid crystal panel (120 in FIG. 2) through a photolithographic process. 2-DTr) of the second gate electrode (not shown), the second gate insulating layer (not shown), the second semiconductor layer (not shown), the second source electrode (not shown), the second drain electrode (not shown) ) is formed, and a second protective layer (129 in FIG. 2), a second pixel electrode (125 in FIG. 2) and a second common electrode (127 in FIG. 2) are formed on the second thin film transistor (2-DTr in FIG. 2). ) to form

In the color filter process (st300), a black matrix (115 in FIG. 2) and a color filter layer (115 in FIG. 2) are placed on the second substrate (102 in FIG. 2) constituting the first liquid crystal panel (110 in FIG. 2) through a photolithography process. 116) of

Next, a cell process (st400) is performed. Looking at the cell process in more detail with reference to FIG. 5, the cell process (st400) includes the first to third alignment layer processes (st410, st420, st430), 2 spool turn forming steps (st440, st500), first and second liquid crystal layer forming steps (st450, st510), first and second bonding steps (st460, 520), coated polarization layer forming step (st470), A fourth planarization layer forming step (st480) and a fourth alignment layer forming step (st490) are included.

Here, the first alignment layer process (st410) is to form a first alignment layer (160 in FIG. 2) on the inner surface of the first substrate (101 in FIG. 2) on which the first thin film transistor (1-DTr in FIG. 2) is formed. , In the formation of the first alignment layer (st411), the first alignment material layer is first coated on the inner surface of the first substrate (101 in FIG. 2).

In addition, after inverting (st412) the first substrate (101 in FIG. 2), a second alignment layer (210 in FIG. 3) is formed on the outer surface of the first substrate (101 in FIG. 2), forming a second alignment layer ( st413) coats the second alignment material layer on the outer surface of the first substrate (101 in FIG. 2).

At this time, the first and second alignment material layers are made of an ultraviolet curable resin composition including photoreactive side chains.

Next, ultraviolet rays are irradiated from one surface of the first substrate (101 in FIG. 2) to proceed with a first alignment process (st414), in which the first and second alignment material layers are simultaneously oriented. is applied to form first and second alignment layers (160 in FIG. 2 and 210 in FIG. 3).

At this time, the ultraviolet rays pass through the first substrate (101 in FIG. 2), and the first and second alignment material layers positioned on the inner and outer surfaces of the first substrate (101 in FIG. 2) are simultaneously aligned.

Here, the ultraviolet rays irradiated to the first substrate (101 in FIG. 2) may impart sufficient energy to cause a photoreaction to the first and second alignment material layers located on both sides of the first substrate (101 in FIG. 2). In particular, since ultraviolet rays must pass through the first substrate (101 in FIG. 2), the transmission efficiency of the glass constituting the first substrate (101 in FIG. 2) must be considered.

Referring to the graph of FIG. 6, it can be confirmed that ultraviolet rays pass through the glass when they have a wavelength of about 280 to 365 nm. In this case, only about 80% of the glass is transmitted.

In addition, when ultraviolet rays have a wavelength of 365 nm, 100% of the glass is transmitted.

response wavelength transmittance Required UV exposure (mJ) 1st alignment material layer Second alignment material layer 365 nm 100% 1000 1000 500 500 310 nm 80% 1000 800 500 400 280 nm 50% 1000 500 500 250

Referring to [Table 1] above, considering the transmittance of the glass substrate for each reaction wavelength of ultraviolet light, the first alignment material layer and the second alignment material layer on the first substrate (101 in FIG. 2) increase the transmittance efficiency of the glass. Considering this, a difference in the amount of exposure received by ultraviolet rays occurs.

Therefore, it is possible to know the exposure amount of ultraviolet rays irradiated to the first alignment material layer and the second alignment material layer. The second alignment film (210 in FIG. 3) of the third polarizing plate (200 in FIG. Since it serves to align the liquid crystal molecules (221 of FIG. 3) of 220 of 2), the first liquid crystal panel (FIG. 2 Compared to the first alignment layer (160 in FIG. 2) of 110 of), a smaller exposure amount may be received.

Here, FIG. 7 is an experimental result obtained by evaluating an afterimage after-image for each exposure energy of a polyimide alignment layer containing cinnamate reacting at 310 nm to 365 nm as a photo-induced polymer.

Referring to FIG. 7 , the anisotropic characteristics of the alignment layer for each exposure energy can be confirmed. At exposure energies of 200 mJ and 400 mJ, light transmission is mottled, which means that the liquid crystal molecules are not evenly aligned.

Therefore, an exposure amount of at least 500 mJ or more is required for alignment treatment of the alignment layer, and considering the afterimage evaluation, the required exposure energy is 800 mJ or more.

Here, referring to [Table 1], since the required exposure energy is at least 800 mJ, the liquid crystal display (100 in FIG. 2) according to the embodiment of the present invention is provided on the outer surface of the first substrate (101 in FIG. 2). It is preferable to use ultraviolet rays of a wavelength of 310 nm to 365 nm having a transmittance of 80% capable of irradiating an exposure energy of at least 800 mJ or more as the second alignment material layer.

That is, the first alignment material layer and the second alignment material layer respectively provided on the inner and outer surfaces of the first substrate (101 in FIG. The first and second alignment layers (160 in FIG. 2 and 210 in FIG. 3) may be simultaneously formed by simultaneously arranging the alignment material layers.

At this time, the first alignment material layer and the second alignment material layer require one or more photoreactive side chains in order to secure alignment by ultraviolet rays of 310 nm to 365 nm wavelength, and are represented by [Formula 1] to [Formula 5] below. Each of the indicated cinnamates, coumarins, chalcones, maleimides, anthracenyl groups, or derivatives thereof may be included.

[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

Next, in the second alignment layer process (st420), a third alignment layer (170 in FIG. 2) is formed on the inner surface of the second substrate (102 in FIG. 2), and the third alignment layer formation (st421) is performed on the second substrate ( After forming the third alignment material layer on the inner surface of 102 in FIG. 2), a second alignment process (st422) of irradiating ultraviolet rays to the third alignment material layer formed on the inner surface of the second substrate (102 in FIG. 2). ) to form a third alignment layer ( 170 in FIG. 2 ).

The third alignment film process (st430) is a process of forming a fourth alignment film (180 in FIG. 2) on the inner surface of the third substrate (121 in FIG. 2) constituting the second liquid crystal panel (120 in FIG. 2). , Formation of the fourth alignment layer (st431) is the fourth alignment material layer formed on the inner surface of the third substrate (121 in FIG. 2), and then the fourth alignment material layer formed on the inner surface of the third substrate (121 in FIG. 2). A third alignment process (st432) of irradiating ultraviolet rays to the material layer is performed to form a fourth alignment layer (180 in FIG. 2) on the third substrate (121 in FIG. 2).

In the next first spool turn forming step (st440), a first spool turn ( not shown).

The first spool turn (not shown) is the inner surface of the first substrate (101 in FIG. 2 ) or the second substrate ( 160 in FIG. 2 ) or the second substrate ( 101 in FIG. 102) of the formed on the inner surface.

In the first liquid crystal layer forming step (st450), a liquid crystal material is dropped and dotted on one of the first and second substrates (101 and 102 in FIG. 2) on which the first failure turns (not shown) are formed. 1 liquid crystal layer (103 in Fig. 2) is formed.

In the first bonding step (st460), the first and second substrates (101 and 102 in FIG. 2) are bonded using a first spool turn (not shown) with the first liquid crystal layer (103 in FIG. 2) interposed therebetween. The first liquid crystal panel (110 in FIG. 2) is completed by bonding.

Thereafter, the cell process (st400) includes a step (st470) of forming a coated polarization layer (220 in FIG. 3) on the second alignment layer (210 in FIG. 3) of the first substrate (101 in FIG. 2), A third planarization layer forming process (st480) of forming a third planarization layer (230 in FIG. 3) on the coated polarization layer (220 in FIG. 3) is performed.

Next, a fourth alignment layer process (st490) is performed, which is a third planarization layer positioned above the coated polarization layer (220 in FIG. 3) of the first substrate (101 in FIG. 2). As a process of forming a fifth alignment layer (190 in FIG. 3) on top of (230 in FIG. 3), the fourth alignment layer process (st490) forms a fifth alignment material layer on top of the third planarization layer (230 in FIG. 3). After the 5th alignment layer formation process (st491), the 5th alignment material layer is irradiated with ultraviolet rays (st492) to form a 5th alignment layer (190 in FIG. 3).

In the next second spool turn forming step (st500), a second spool turn (not shown) is formed along the edge of the third substrate (121 in FIG. 2).

In the second liquid crystal layer forming step (st510), the liquid crystal material is dropped and dotted onto the substrate (121 in FIG. 2) on which the second spool turn (not shown) of the third substrate (121 in FIG. 2) is formed. 2 liquid crystal layers (123 in FIG. 2) are formed.

In the second bonding step (st520), the first substrate of the first liquid crystal panel (110 in FIG. 2) is formed by using a second spool turn (not shown) with the second liquid crystal layer (123 in FIG. 2) interposed therebetween. (101 in FIG. 2) and the third substrate (121 in FIG. 2) are bonded together to complete the second liquid crystal panel (120 in FIG. 2).

When the first and second liquid crystal panels (110 and 120 in FIG. 2) are completed, a module process (st600) is performed. In the module process (st600), the first liquid crystal panel (shown in FIG. 110) and the second liquid crystal panel (120 in FIG. 2) by attaching a driving circuit and disposing a backlight (130 in FIG. 2) under the second liquid crystal panel (120 in FIG. 2) to modularize the embodiment of the present invention. According to the liquid crystal display device (100 in FIG. 2) is completed.

The liquid crystal display device (100 in FIG. 2) completed through this manufacturing method adjusts the transmittance of light supplied from the backlight (130 in FIG. 2) through the second liquid crystal panel (120 in FIG. By supplying to 110 of 2), the contrast ratio of the image implemented in the first liquid crystal panel (110 of FIG. 2) is improved.

In particular, as the coated polarizer (200 in FIG. 3) is positioned between the first liquid crystal panel (110 in FIG. 2) and the second liquid crystal panel (120 in FIG. 2), transmission and blocking of light can be realized more clearly. The overall transmission efficiency of the liquid crystal display device (100 in FIG. 2) is improved.

In addition, by simultaneously rubbing the first alignment film (160 in FIG. 2 ) and the second alignment film (210 in FIG. 3 ) positioned on both sides of the first substrate (101 in FIG. 2 ) through a photo alignment method, The efficiency of the process is improved.

In addition, light leakage caused by the distortion of the polarization axis between the first alignment layer (160 in FIG. 2) and the second alignment layer (210 in FIG. 3) does not occur, thereby improving the contrast ratio of the image.

That is, the first alignment layer (160 in FIG. 2) and the second alignment layer (210 in FIG. 3) positioned on both sides of the first substrate (101 in FIG. Alignment axes of 160 in FIG. 2 ) and the second alignment layer ( 210 in FIG. 3 ) are formed identically.

Therefore, it can have an effect of improving light leakage. Table 2 below shows the luminance increase rate due to light leakage according to the distortion of the alignment axis between the first alignment layer (160 in FIG. 2) and the second alignment layer (210 in FIG. 3). This is the measured experimental result.

Optical axis misalignment (ΔΘ) Luminance increase rate (%) 1.0 2.28% 0.8 1.45% 0.6 0.81% 0.4 0.35% 0.2 0.08% 0.0 0.00%

Looking at [Table 2] above, when the alignment axes of the first alignment film (160 in FIG. 2) and the second alignment film (210 in FIG. 3) positioned on both sides of the first substrate (101 in FIG. 2) are twisted, It can be confirmed that the luminance increase due to the light leakage occurs.

However, when the first alignment layer (160 in FIG. 2 ) and the second alignment layer (210 in FIG. 3 ) are simultaneously rubbed through the optical alignment method as in the embodiment of the present invention, the liquid crystal display according to the embodiment of the present invention ( 100 in FIG. 2) indicates that the distortion of the alignment axis between the first alignment layer (160 in FIG. 2) and the second alignment layer (210 in FIG. 3) is 0, and the first alignment layer (160 in FIG. 2) and the second alignment layer (210 in FIG. 210 of ) can prevent light leakage from occurring due to the twist of the orientation axis between the .

The liquid crystal display device (100 in FIG. 2) according to an embodiment of the present invention adjusts the transmittance of light supplied from the backlight (130 in FIG. 2) through the second liquid crystal panel (120 in FIG. By supplying to 110 of 2), the contrast ratio of the image implemented in the first liquid crystal panel (110 of FIG. 2) is improved.

In particular, as the coated polarizer (200 in FIG. 3) is positioned between the first liquid crystal panel (110 in FIG. 2) and the second liquid crystal panel (120 in FIG. 2), transmission and blocking of light can be implemented more clearly. The overall transmission efficiency of the liquid crystal display device (100 in FIG. 2) is improved.

In addition, by simultaneously rubbing the first alignment film (160 in FIG. 2 ) and the second alignment film (210 in FIG. 3 ) positioned on both sides of the first substrate (101 in FIG. 2 ) through a photo alignment method, The efficiency of the process is improved.

The present invention is not limited to the above embodiments, and can be practiced with various changes without departing from the spirit of the present invention.

100: liquid crystal display
101, 102: first and second substrates
103: first liquid crystal layer
104: first gate electrode, 105: first gate insulating layer, 106: semiconductor layer, 107, 108: first source and first drain electrodes, 109: first protective layer (109a: first drain contact hole)
110: first liquid crystal panel
111: first pixel electrode, 113: first common electrode
115: first black matrix, 116: color filter layer, 117: first planarization layer
120: second liquid crystal panel
121: third substrate, 123: second liquid crystal layer, 125: second pixel electrode, 127: second common electrode, 128: second black matrix, 129: second protective layer (129a: second drain contact hole)
130: backlight
140, 150: first and second polarizers
160, 170: first and third alignment layers
180, 190: fourth and fifth alignment layers
200: third polarizer

Claims (10)

coating a first alignment material layer on the inner surface of the first substrate;
coating a second alignment material layer on an outer surface of the first substrate;
Photo-alignment step of irradiating UV from the top of the first substrate
Including,
In the optical alignment step, the first and second alignment material layers are simultaneously aligned, so that first and second alignment films are provided on both sides of the first substrate, respectively.
The first alignment material layer and the second alignment material layer are cinnamate, coumarin, and chalcone each represented by [Formula 1] to [Formula 5] below having at least one photoreactive side chain. ), maleimide, an anthracenyl group or a derivative thereof,
The first substrate is made of glass, and the UV has a wavelength of 310 nm to 365 nm and an exposure energy of 800 mJ or more.
[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

delete According to claim 1,
A method of manufacturing a liquid crystal display device comprising the step of forming a coating type polarization layer on the second alignment layer.
According to claim 3,
positioning a second substrate including a first liquid crystal layer and a third alignment layer on top of the first alignment layer;
The method of manufacturing a liquid crystal display device in which the first substrate, the second substrate, and the first liquid crystal layer form a first liquid crystal panel.
According to claim 4,
Forming a fifth alignment layer on top of the coated polarization layer;
positioning a third substrate including a second liquid crystal layer and a fourth alignment layer on top of the fifth alignment layer;
The method of manufacturing a liquid crystal display device in which the first substrate, the third substrate, and the second liquid crystal layer form a second liquid crystal panel.
According to claim 5,
positioning a first polarizing plate having a polarization axis in a first direction outside the second substrate and positioning a second polarizing plate having a polarization axis in a first direction outside the third substrate;
The coating type polarization layer has a polarization axis in a second direction perpendicular to the first direction.
According to claim 6,
and locating a backlight under the second liquid crystal panel,
The second liquid crystal panel controls the light emitted from the backlight and supplies it to the first liquid crystal panel.
According to claim 6,
Before forming the fifth alignment layer on the coated polarization layer,
The manufacturing method of the liquid crystal display device further comprising the step of providing a planarization layer on top of the coated polarization layer.
According to claim 5,
The first liquid crystal panel and the second liquid crystal panel each include a first pixel area and a second pixel area,
The second pixel area is larger than the first pixel area.
coating a first alignment material layer on the inner surface of the first substrate;
coating a second alignment material layer on an outer surface of the first substrate;
Photo-alignment step of irradiating UV from the top of the first substrate
Including,
In the optical alignment step, the first and second alignment material layers are simultaneously aligned, so that first and second alignment films are provided on both sides of the first substrate, respectively.
The first alignment material layer and the second alignment material layer are cinnamate, coumarin, and chalcone each represented by [Formula 1] to [Formula 5] below having at least one photoreactive side chain. ), maleimide, an anthracenyl group or a derivative thereof,
forming a coated polarization layer on the second alignment layer;
positioning a second substrate including a first liquid crystal layer and a third alignment layer on top of the first alignment layer;
forming a fifth alignment layer on the coated polarization layer;
positioning a third substrate including a second liquid crystal layer and a fourth alignment layer on top of the fifth alignment layer;
positioning a first polarizing plate having a polarization axis in a first direction outside the second substrate and positioning a second polarizing plate having a polarization axis in the first direction outside the third substrate;
Before forming the fifth alignment layer on the coated polarization layer, providing a planarization layer over the coated polarization layer.
Including more,
The first substrate, the second substrate and the first liquid crystal layer form a first liquid crystal panel,
The first substrate, the third substrate, and the second liquid crystal layer form a second liquid crystal panel;
The coated polarization layer has a polarization axis in a second direction perpendicular to the first direction,
The second alignment layer, the coated polarizing layer, and the planarization layer constitute a third polarizing plate;
The third polarizing plate is thinner than the first polarizing plate and the second polarizing plate.
[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

Images