KR100928483B1 - Manufacturing method of multi-domain liquid crystal display - Google Patents

Abstract

The present invention relates to a method for manufacturing a multi-domain liquid crystal display device, comprising: a first step of preparing a first substrate in which each pixel region is defined by a first region and a second region, and the first substrate of the first substrate; A second step of forming a first alignment layer in one region, and forming a second alignment layer having a different pretilt angle from the first alignment layer in the second region, and simultaneously rubbing the first and second alignment layers of the first substrate It is characterized in that it comprises a third step of the alignment process to have a different pretilt angle.

      Multi-domain, pixel, first alignment layer, second alignment layer, rubbing

Description

Method for manufacturing multi-domain liquid crystal display device {Method For Fabricating A Multi-Domain Liguid Crystal Display Device}

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

2 is a cross-sectional view of an alignment film printing apparatus according to the prior art.

3A to 3C are cross-sectional views of a multi-domain liquid crystal display device according to the prior art.

4A to 4D are cross-sectional views of a multi-domain liquid crystal display device using the ink jet printer according to the first embodiment of the present invention.

5A to 5D are cross-sectional views of a multi-domain liquid crystal display using spray according to a second embodiment of the present invention.

            * Explanation of symbols on the main parts of the drawings

200: first substrate 201: first region

202: second region 203: inkjet printer

304: spray device 303: mask

204: First alignment layer 205: Second alignment layer

206: rubbing cloth 207: rubbing roll

208: low pretilt angle 209: high pretilt angle

210: second substrate 211: liquid crystal layer

The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly, to a method for manufacturing a multi-domain liquid crystal display device.

As the information society develops, the demand for display devices is increasing in various forms.In recent years, liquid crystal display (LCD), plasma display panel (PDP), electro luminescent display (ELD), and vacuum fluorescent display (VFD) have been developed. Various flat panel display devices have been studied, and some of them are already used as display devices in various devices.

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

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

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

In a liquid crystal display having such a structure, a multi-domain liquid crystal display having one pixel having at least two different alignment directions as a method for improving the viewing angle has recently received much attention. have.

Such a liquid crystal display device may be broadly divided into a liquid crystal panel displaying an image and a driving unit for applying a driving signal to the liquid crystal panel, wherein the liquid crystal panel includes first and second glass substrates having a space and are bonded to each other; It consists of a liquid crystal layer injected between the said 1st, 2nd glass substrate.

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

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

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

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

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

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

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

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

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

Here, the thin film transistor T may include a gate electrode protruding from the gate wiring 4, a gate insulating film (not shown) formed on the front surface, an active layer formed on the gate insulating film above the gate electrode, and And a source electrode protruding from the data line 5 and a drain electrode opposed to the source electrode.

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

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

Of course, there are some differences depending on the normally white mode or the normally black mode, but depending on the data signal voltage applied to each pixel electrode through the thin film transistor T, The orientation direction of the liquid crystal molecules is changed to adjust the amount of light passing through the liquid crystal layer 3, thereby displaying an image.

A twisted nematic (TN) liquid crystal is mainly used as the liquid crystal layer. TN liquid crystal has a problem that the viewing angle is narrowed because the refractive index of the light oscillating in the long axis direction of the liquid crystal molecules and the light oscillating in the direction perpendicular to the long axis direction show different refractive index anisotropy.

Therefore, a multi-domain liquid crystal display capable of compensating viewing angles by dividing a unit pixel into at least two domains so that liquid crystals are oriented in different directions in each domain so that the direction of viewing angle of each domain is different. The device has been proposed.

Referring to the conventional multi-domain liquid crystal display as described above with reference to the accompanying drawings as follows.

In the multi-domain, an alignment direction of the alignment layer of each region divided into at least two pixel regions is different from each other, thereby describing a process of depositing and rubbing the alignment layer.

2 is an alignment film printing apparatus for forming an alignment film according to the prior art.

The alignment film printing apparatus, as shown in Figure 2, the polyimide liquid from the storage tank 16 through the storage tank 16 and the supply line 17 for storing the polyimide liquid 15 that is the alignment liquid A dispenser 14 for dropping (15) constantly and a doctor roll 13 formed in engagement with each other to spread the polyimide liquid 15 from the dispenser 14 to the surface 18 of the roll with a uniform thickness. And printing to transfer the polyimide liquid 15 formed to a uniform thickness by the anilox roll 12 and the doctor roll 13 and the anilox roll 12 to the first substrate 10. It is comprised with the roll 11 and the printing table 19 in which the said board | substrate 10 is mounted.

By using the alignment film printing apparatus, as shown in FIG. 2, the poly is deposited on the first substrate 10 and the second substrate (not shown) on which the common electrode is formed after completing the TFT array process and the pixel electrode process. An alignment film such as the mid liquid 15 is applied uniformly.

The method of manufacturing the multi-domain liquid crystal display device according to the prior art will be described with reference to FIGS. 3A to 3C with the first substrate 10 coated with the alignment layer.

3A illustrates the surface of the alignment film 101 on the first substrate using the first substrate 100 on which the alignment film 101 is formed by the alignment film printing apparatus, using the rubbing roll 103 with the rubbing cloth 102 attached thereto. It is sectional drawing which carries out a rubbing process so that it may have this 1st direction.

Here, the rubbing roll 103 to which the rubbing cloth 102 is attached is rotated in place, and the rubbing roll is moved by moving the first substrate 100 on which the alignment layer 101 is formed in the direction of the arrow indicating the substrate advancing direction. The surface of the first substrate 100 is rubbed in the first direction by being in contact with the 103.

Thereafter, as illustrated in FIG. 3B, the first substrate 100 that has completed the rubbing process cuts about one half of each pixel region for each pixel region by using the mask 105, and then emits ultraviolet (UV) light; 104 is irradiated so that the pretilt angle 105 of the alignment layer 101 of the remaining region of the region exposed from the ultraviolet (UV) 104 is smaller than the pretilt angle 106 of the alignment layer of the unexposed region.

A cleaning process for removing radicals emanating from the polyimide molecules forming the alignment layer of the first substrate 100 having the pretilt angle 105 is performed.

As described above, the second substrate 107 also performs a multi-domain process in the same process as the first substrate 100. As shown in FIG. 3C, after the first substrate 100 and the second substrate 107 are bonded together, the liquid crystal 108 is disposed between the first substrate 100 and the second substrate 107. Inject                         

Here, in the bonding process, the first substrate 100 and the second substrate 107 face differently oriented surfaces so that the directions of the average liquid crystal molecules are opposite to each other.

From this, it is possible to compensate for the viewing angle by causing the main viewing angles of the two regions to be opposite to each other when the electric field is applied.

However, the conventional method for manufacturing a multi-domain liquid crystal display device has the following problems.

First, after first rubbing the entire surface of the alignment layer of the substrate in one direction, each pixel region is partially exposed to ultraviolet rays (UV) to form a multi-domain, so that the tack time is determined by the ultraviolet (UV) irradiation time. This lengthens.

Second, since the cleaning process is required to remove radicals from the polyimide molecules constituting the alignment layer after ultraviolet (UV) irradiation, the process is complicated.

The present invention has been made to solve the above problems, and an object thereof is to provide a manufacturing method of a multi-domain liquid crystal display device which can improve productivity by shortening process time and maximizing efficiency.

According to an aspect of the present invention, there is provided a method of manufacturing a multi-domain liquid crystal display device, including: a first step of preparing a first substrate in which each pixel area is defined as a first area and a second area; And forming a first alignment layer in the first region of the first substrate, and forming a second alignment layer in the second region, the second alignment layer having a different alignment characteristic from the first alignment layer, and the first substrate of the first substrate. And a third step of rubbing the second alignment layer at the same time so as to have a different pretilt angle.

The method may further include a cleaning process of removing foreign substances and particles of the first substrate and the second substrate before forming the first alignment layer and the second alignment layer in each region of the first substrate. .

It is preferable to use an inkjet printer or a spray as the alignment film printing apparatus.

The inkjet printing method using the inkjet printer is a method of patterning printing the alignment film on the first substrate using the inkjet printer, the spray method using a spray is a method of spraying the alignment film with the compressed air in the spray through a nozzle to be.

Specifically, when the alignment film is printed using the inkjet printer as the alignment film printing apparatus, the first alignment film is formed in the first area of each pixel area of the first substrate, and the second area is It is preferable to pattern-print the second alignment film to the size and shape stored in the inkjet printer.

When the alignment layer is printed using the spray method, the second region of the first substrate is blocked with a mask, and the exposed first region of the first substrate is sprayed to print the first alignment layer. After that, the printed first area of the first substrate is blocked by the mask, and the exposed second area of the printed first substrate is preferably sprayed on the second alignment layer to print.

Preferably, the first and second alignment layers of the first substrate printed by the inkjet printing method or the spray method are subjected to baking to allow the alignment layer to be completely cured and then to be rubbed.

The rubbing process rotates the rubbing roll to which the rubbing cloth is attached and moves the first substrate in a predetermined direction by using a stage and a driving roller supporting the first substrate so that the alignment layer passes through the rubbing cloth. It is preferable to form a pattern in the.

In this way, the first substrate on which the different pretilt angles are formed and the second substrate on which the alignment layer is not formed are bonded to each other so that the alignment layer of the first substrate, the color filter array of the second substrate, and the surface on which the black matrix layer is formed face each other. It is desirable to see.

 In addition, an alignment layer may be formed to have a different pretilt angle between the second substrate and the second substrate by the same process as that of the first substrate. However, after the second alignment layer is formed in the first region of the second substrate and the first alignment layer is formed in the second region, the second alignment layer is bonded. Thus, the bonded first and second substrates face each other with a different dormant film.

Thereafter, a liquid crystal layer is formed between the bonded substrates.

Two methods of a liquid crystal injection type and a liquid crystal dropping type are used for the method of forming the said liquid crystal layer. The liquid crystal injection method is a method in which the liquid crystal is injected between the two substrates by osmotic pressure by holding the bonded first substrate and the second substrate in a vacuum state so that the liquid crystal injection hole is immersed in the liquid crystal liquid. The method is a method of printing a sealing compound without an injection hole on the substrate and dropping the liquid crystal thereon to bond the color filter substrate and the TFT substrate.

Hereinafter, a method of forming a multi-domain liquid crystal display device according to the present invention will be described in detail with reference to the accompanying drawings.

4A to 4D are cross-sectional views illustrating a method of manufacturing a multi-domain liquid crystal display device using the ink jet printer according to the first embodiment of the present invention.

As shown in FIG. 4A, each pixel area of the first substrate 200 is divided into at least two areas (the first area 201 and the second area 202), and the inkjet printer 203 is provided. A low pretilt alignment liquid is embedded in the inside) to uniformly print the alignment liquid in the first region 201 and to dry for at least 5 minutes to form the first alignment layer 204.

Subsequently, as shown in FIG. 4B, a high pretilt alignment liquid is uniformly printed on the second region 202 of the first substrate 200 by using the inkjet printer 203. It is dried for at least 5 minutes to form the second alignment layer 205.

In this case, a method of forming the first alignment layer 204 and the second alignment layer 205 using the inkjet printer 203 is a patterning printing method. The patterning printing method is a method of taking out while moving the alignment film of a certain shape.                     

In this manner, the first alignment layer 204 and the second alignment layer 205 are formed in the first and second regions of the first substrate, and the first substrate is baked to be cured.

As shown in FIG. 4C, the first and second alignment layers 204 and 205 are subjected to a rubbing process simultaneously to align the first and second alignment layers 204 and 205.

That is, the rubbing process rotates the rubbing roll 207 to which the rubbing cloth 206 is attached in place, and shows the first substrate 200 on which the first and second alignment layers 204 and 205 are formed. As described above, the first alignment layer 204 is rubbed to have a low pretilt angle 208 (θ ₂ ) by moving in the direction of the arrow in the substrate advancing direction and contacting the rubbing roll 207. The two alignment layers 205 are rubbed to have a high pretilt angle 209 (θ ₃ ).

After doing this, as described above, the second substrate 210 also forms different pretilt angles in the same process as the first substrate 200.

A second alignment layer 205 is formed in the first region 201 of the second substrate 210, and a first alignment layer 204 is formed in the second region 202, as shown in FIG. 4D. After bonding with the first substrate, the alignment layers having different pretilt angles face each other.

Thereafter, when the liquid crystal is injected between the bonded substrates, the liquid crystal layer 211 is formed. Although not shown in the drawings, a spacer is scattered to have a predetermined space between the first substrate 200 and the second substrate 210.                     

5A to 5D illustrate a method of forming a multidomain using a spray according to a second embodiment of the present invention.

As shown in FIG. 5A, each of the pixel areas of the first substrate 300 is divided into at least two areas (the first area 301 and the second area 302), and the spray device 304 is provided. ) Is sprayed through the nozzle (not shown in the figure), printed and sprayed and dried for at least 5 minutes.

That is, the second alignment layer 302 of each pixel region is blocked by the mask 303, and a first alignment liquid having a low pretilt angle is sprayed on the first region to form a first alignment layer 305. ). In this case, the mask 303 should be aligned exactly on the second region 302 so that the first alignment liquid does not invade the second region 302.

Thereafter, as shown in FIG. 5B, the first region 301 of the first substrate 300 is blocked by the mask 303, and a high pretilt angle is applied to the second region 302. Of the alignment liquid is sprayed using the spray 304 to print the second alignment layer 306 and to dry for at least 5 minutes.

In this case, the mask 303 must be exactly aligned on the first region 301 so that the second alignment liquid does not invade the first region 301.

As such, when the first alignment layer 305 and the second alignment layer 306 are formed in the first and second regions of the first substrate 300 and the first substrate is plasticized and cured, the first substrate 300 is illustrated in FIG. 5C. As described above, the first alignment layer 305 and the second alignment layer 306 are simultaneously subjected to a rubbing process to align the alignment layer.

That is, in the rubbing process, the rubbing roll 308 to which the rubbing cloth 307 is attached is rotated in place, and the first substrate 300 on which the alignment layer is printed is moved in the direction of the substrate advancing direction, so that the rubbing roll ( 308, the first alignment layer 305 is formed to have a low pretilt angle 309; θ ₂ , and the second alignment layer 306 has a high pretilt angle 310. ₃ )

After doing this, as described above, the second substrate 311 also forms different pretilt angles in the same process as the first substrate 300.

As shown in FIG. 5D, a second alignment layer 306 is formed in the first region 301 of the second substrate 311, and a first alignment layer 305 is formed in the second region 302. After bonding the first substrate 300 and the second substrate 311, the alignment layers having different pretilt angles face each other.

Thereafter, a liquid crystal is injected between the bonded substrates to form a liquid crystal layer 312.

Although not shown in the drawings, a spacer is scattered to have a predetermined space between the first substrate 300 and the second substrate 312.

As described above, the method of forming the multi-domain of the liquid crystal display according to the present invention has the following effects.

First, since the alignment layers having different pretilt angles are formed in the first region and the second region and rubbed at the same time to have different pretilt angles, the alignment control force is greatly improved to prevent light leakage. Can be.

Secondly, since it is not necessary to irradiate ultraviolet (UV) radiation, which is conventionally used for forming a multi-domain, and does not require cleaning after the ultraviolet (UV) irradiation, it is possible to greatly reduce the tact time and simplify the process. You can.

Claims (13)

A first step of preparing a first substrate in which each pixel region is defined by a first region and a second region; Forming a first alignment layer in the first region of the first substrate and forming a second alignment layer having a different pretilt angle from the first alignment layer in the second region; And, And rubbing the first and second alignment layers of the first substrate at the same time to align the first and second alignment layers to have different pretilt angles. The method of claim 1, The third step may further include firing the first and second alignment layers before rubbing the first substrate on which the first alignment layer and the second alignment layer are formed. Manufacturing method. The method of claim 1, The second step may further include drying at least five minutes after forming the first and second alignment layers of the first substrate, respectively. The method of claim 1, The second step is a method of manufacturing a multi-domain liquid crystal display device, characterized in that formed by the inkjet printing method or spray method. The method of claim 4, wherein The inkjet printing method is a method for manufacturing a multi-domain liquid crystal display device, characterized in that the first and second alignment films are formed on the first substrate by a patterned printing method. The method of claim 4, wherein In the spray method, when the first alignment layer is formed in the first region of the first substrate, blocking the second region of the first substrate with a spray mask, and removing the first alignment film in the second region of the first substrate. 2. A method of manufacturing a multi-domain liquid crystal display device, the method comprising: blocking the first region of the first substrate with the spray mask when forming the alignment layer. The method of claim 1, Preparing a second substrate in which each pixel region is defined as a first region and a second region; A fifth step of forming the first alignment layer in the first region of the second substrate and forming the second alignment layer in the second region; And, And a sixth step of rubbing the first and second alignment layers of the second substrate at the same time so as to have different pretilt angles. The method of claim 7, wherein The fifth step may further include firing the first and second alignment layers before rubbing the second substrate on which the first alignment layer and the second alignment layer are formed. Manufacturing method. The method of claim 7, wherein The fifth step may further include drying the first and second alignment layers of the second substrate, followed by drying for at least 5 minutes. The method of claim 7, wherein And after the sixth step, attaching the alignment layers having different pretilt angles of the first substrate and the second substrate to face each other. The method of claim 7, wherein The fifth step is a method of manufacturing a multi-domain liquid crystal display device, characterized in that formed by the inkjet printing method or spray method. The method of claim 11, The inkjet printing method is a method of manufacturing a multi-domain liquid crystal display device, wherein the first and second alignment films are formed on the second substrate by a patterned printing method. The method of claim 11, In the spray method, when the first alignment layer is formed in the first region of the second substrate, blocking the second region of the second substrate with a spray mask, and removing the second alignment region in the second region of the second substrate. 2. A method of manufacturing a multi-domain liquid crystal display device, further comprising: blocking the first region of the second substrate with the spray mask when forming the alignment layer.

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