KR20150027474A - Liquid crystal display device and fabricating method thereof - Google Patents

Abstract

The present invention relates to a liquid crystal display device and a manufacturing method thereof. The liquid crystal display device includes a first substrate which includes a spacer formed on an active region, a hydrophobic spacer formed on a margin region, and a first alignment layer, a second substrate which includes hydrophobic patterns on the margin region and a second alignment layer, a liquid crystal layer which is formed on the active region and the margin region between the first and second substrates, and a sealing agent which is formed on the margin region and bonds the first and second substrates.

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal display (LCD)

The present invention relates to a liquid crystal display device having a narrow bezel and a method of manufacturing the same.

A liquid crystal display device of an active matrix driving type displays a moving picture by using a thin film transistor (hereinafter referred to as "TFT") as a switching element. This liquid crystal display device can be downsized as compared with a cathode ray tube (CRT), and is applied to a display device in a portable information device, an office machine, a computer, etc., and is rapidly applied to a television, thereby rapidly replacing a cathode ray tube.

1 shows a part of a pixel array in an active matrix liquid crystal display device.

Referring to FIG. 1, a TFT (Thin Film Transistor) array is formed on a lower substrate GLSL of a liquid crystal display, and a color filter array is formed on an upper substrate GLSU. The TFT array of the lower substrate GLSL includes data lines DL and gate lines GL intersecting with each other, TFTs formed at intersections of data lines and gate lines, and pixel electrodes connected to TFTs respectively . The color filter array of the upper substrate GLSU includes a black matrix BM, a color filter CF and a common electrode COM. The common electrode COM is formed on the upper plate in a vertical electric field driving method such as a TN (Twisted Nematic) mode and a VA (Vertical Alignment) mode. The common electrode COM is formed on the lower substrate GLSL together with the pixel electrode PXL in a horizontal electric field driving method such as IPS (In Plane Switching) mode and FFS (Fringe Field Switching) mode as shown in FIG.

A lower polarizer is attached to the light incident surface of the lower substrate GLSL and an upper polarizer having a light absorption axis orthogonal to the light absorption axis of the lower polarizer is attached on the light exit surface of the upper substrate GLSU. An alignment film is formed on a surface of the lower substrate GLSL and the upper substrate GLSU that is in contact with the liquid crystal layer LC.

An alignment film for setting a pre-tilt angle of liquid crystal molecules is essentially formed in a liquid crystal display device because liquid crystal molecules can not be aligned uniformly by simply injecting liquid crystal material between the substrates .

As the alignment film printing process, a roll type printing apparatus as shown in Fig. 2 is used. In recent years, studies have been made on techniques for applying low-viscosity alignment films by ink-jet, but until now, it has been difficult to develop materials for equipment and low viscosity alignment films. In particular, in the inkjet coating technique, since the low-viscosity alignment layer solution spreads widely, the liquid crystal margin of the display panel is widened, making narrow bezel difficult to implement. For this reason, alignment film printing apparatuses as shown in Figs. 2 and 3 are applied to most liquid crystal module manufacturers.

2 and 3, the alignment film printing apparatus includes a printing roller 21 on which a printing plate (or a resin plate) 20 is wound, an anilox roller 22, a doctor blade 24, a dispenser, 25), and a doctor roller (26).

An alignment film solution (23) is applied to the anilox roller (22). The alignment film solution 23 applied to the anilox roller 22 is transferred to the printing roller 21 while the anilox roller 22 and the printing roller 21 are rotated in opposite directions.

The doctor blade 24 constantly adjusts the thickness of the alignment film solution 23 supplied to the anilox roller 22 by the dispenser 25. In order to make the thickness of the alignment film solution applied to the anilox roller 22 more uniform, a doctor roller 26 is required in the alignment film printing apparatus as shown in Fig. The doctor roller 26 rotates in the direction opposite to the anilox roller 22 to press the alignment film solution 23 applied on the anilox roller 22.

The printing roller 21 contacts the anilox roller 22 and receives the alignment film solution 23 from the anilox roller 22. The alignment film solution 23 generally includes a polyimide. A pattern 20a is formed on the printing plate 20 to be in contact with the glass substrate GLS. In the pattern 20a, fine grooves filled with the alignment film solution are formed. When the printing roller 21 rotates and the substrate GLS placed on the stage STG passes under the printing roller 21 at a constant speed as indicated by an arrow, The applied alignment film solution 23 is transferred onto the substrate GLS.

When the alignment film is printed on the substrate GLS by using the alignment film printing apparatus as shown in Fig. 2, there is a problem that the alignment film solution 23 is gathered at the pattern end 20b of the printing plate 20 and its thickness becomes thick. This will be described in detail with reference to FIGS. 4 to 7. FIG.

4 to 7, when the pattern 20a of the printing plate 20 transfers the alignment film solution to the substrate GLS while the printing roller 21 rotates, the pattern 20a presses the alignment film solution 23 And the alignment film solution 23 is pushed out of the pattern 20a. As a result, the alignment film solution 23 is gathered at the end 20b of the pattern 20a to form a mount 30 (hereinafter referred to as PI "mount"). In Fig. 7, the x-axis represents the distance (μm) in the vicinity of the boundary between the alignment film printing section and the alignment film non-printing section, and the y-axis represents the alignment film thickness (Å).

The PI mount 30 may be damaged by the rotating rubbing cloth after the orientation film is cured and may contaminate the rubbing cloth or may remain as foreign matter in the pieces or the liquid crystal layer LC by the fine particles, In addition, the PI mount 30 widens the liquid crystal margin area MAR shown in Fig. This is because the width of the PI mount 30 increases when the PI mount 30 is increased. The alignment film solution 23 has a low ability to assemble with the sealant (SL). Therefore, the prior art has widened the margin area MAR so that the alignment film solution 23 does not overlap with the sealant SL. However, the method of widening the marginal area (MAR) increases the bezel area by that much, which makes it difficult to implement the narrow bezel.

6, the bezel region includes a margin region MAR and a pad region PAD. The active area A / A includes a pixel array in which an input image is displayed. The pad region PAD includes data pads connected to the data lines of the active region A / A. In addition, the pad region PAD may further include gate pads connected to the gate lines of the active region A / A. Output terminals of an FPC (Flexible Printed Circuit) mounted with a data drive IC (Integrated Circuit) for outputting a data voltage are connected to the data pads through an anisotropic conductive film (ACF). In Fig. 6, "OC" is an overcoat layer covering the color filter CF and the black matrix BM and flattening the surface thereof.

The margin region MAR includes an alignment film and a sealant SL. The margin region MAR is ensured in consideration of the spreading of the alignment film solution 23 at the time of printing the alignment film. Since the viscosity of the alignment film solution 23 is low, the alignment film printing method using an inkjet spreads the alignment film solution more widely, making it difficult to implement a narrow bezel. On the other hand, a method of removing a part of the alignment layer by irradiating a laser to the alignment layer formed on the margin region (MAR) may be considered. However, additional processes and equipment development are required to implement this method.

In the prior art, the margin area MAR is generally secured at 600 mu m or more from the active area A / A. This is because it is difficult to precisely define the alignment film coating area due to the spreading of the alignment film solution 23 in the alignment film printing process. When the margin area MAR is narrowed, unevenness such as frame-like unevenness or liquid-dirt unevenness can be seen in the display area.

When the alignment film and the sealant SL are overlapped, the combined force of the upper plate and the lower plate of the display panel is lowered. Therefore, in the prior art, a predetermined distance or more is secured between the alignment film and the sealant SL so that they do not overlap with each other. The distance between the sealant SL and the scribe line of the upper substrate GLSU is spaced at an appropriate distance such that the sealant SL is not damaged in the scribing process. The scribing line is the end of the upper substrate (GLSU) in Fig.

The present invention provides a liquid crystal display device and a method of manufacturing the same that minimize the spread of an alignment layer in a narrow bezel.

A liquid crystal display device of the present invention includes: a first substrate including a spacer formed in an active region and a hydrophobic spacer formed in a margin region, the first substrate having a first alignment layer; A second substrate including hydrophobic patterns formed in the margin region and having a second alignment layer formed thereon; A liquid crystal layer formed between the first and second substrates in the active region and the margin region; And a sealant formed in the margin region to bond the first and second substrates together.

The method includes forming spacers and a first alignment layer on a first substrate; Forming hydrophobic patterns and a second alignment layer on a second substrate; Forming an encapsulant in a margin region of one of the first and second substrates and forming a liquid crystal layer between the first and second substrates; And bonding the first and second substrates together with the sealant.

The present invention can minimize the spread of the orientation film in the narrow bezel by forming a hydrophobic surface in the margin region. As a result, the present invention can minimize the overlap between the orientation film and the sealant in the narrow bezel, thereby improving the adhesion between the substrates.

1 is a perspective view showing a partial structure of a pixel array in an active matrix liquid crystal display device.
2 is a sectional view showing an alignment film printing apparatus.
3 is a view showing in detail the alignment film solution applied to the pattern of the printing plate.
FIGS. 4 and 5 are views showing alignment film mounts generated by the jumping of the alignment film solution. FIG.
6 is a cross-sectional view showing an active region, a margin region, and a pad region in the display panel.
7 is a view showing the alignment film step difference between the alignment film printing section and the alignment film non-printing section.
8 is a cross-sectional view illustrating a liquid crystal display device according to an embodiment of the present invention.
9 is a cross-sectional view illustrating a method of manufacturing a hydrophobic column spacer.
FIGS. 10 and 11 are views showing examples of nanostructures for realizing a super water-repellent surface.
12 is a view showing the contact angle of the hydrophobic surface using the nanostructure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

The manufacturing process of a liquid crystal display device according to an embodiment of the present invention includes a substrate cleaning process, a substrate patterning process, an orientation film printing process and a rubbing process, a substrate adhering process and a liquid dropping process, a mounting process, an inspection process, a repair process, . The substrate cleaning process removes contaminants on the surface of the substrate of the liquid crystal display element with a cleaning liquid.

The substrate patterning process includes a step of patterning the thin films formed on the upper substrate (GLSU), and a step of patterning the thin films formed on the lower substrate (GLSL).

The alignment film printing and rubbing process includes a step of printing the alignment film solution by surface-treating the surface of the substrate in a margin region by hydrophobic treatment, and a step of rubbing or orienting the alignment film with a rubbing cloth or the like.

The substrate bonding and liquid crystal dropping process draws an encapsulant (SL) on one of the upper and lower substrates (GLSU and GLSL) and drops liquid crystal on another substrate. The case where the sealing agent is applied to the upper substrate GLSU and the liquid crystal LC is dropped on the lower substrate GLSL will be described by fixing the upper substrate GLSU on which the sealing material is formed to the upper stage, The lower substrate GLSL to which the liquid crystal layer LC is dropped is fixed to the lower stage. The sealant may be selected from a thermosetting sealant or a photo-curable sealant. After the upper substrate GLSU and the lower substrate GLSL are aligned, a vacuum pump is driven to apply pressure to at least one of the stages in a vacuum state to bond the upper substrate GLSU and the lower substrate GLSL. The ultraviolet light source is then turned on to cure the sealant when the sealant is selected as a photo-curable sealant.

In the mounting process, a driving integrated circuit is mounted on a lower substrate (GLSL) by a TAB (Tape Automated Bonding) process, a COG (Chip on Glass) process, or the like. The gate drive IC may be formed directly on the lower substrate together with the TFT array. The inspection process includes an inspection for an integrated circuit (IC), a signal wiring inspection of a data line and a gate line formed in a lower substrate (GLSL), an inspection performed after a pixel electrode is formed, a substrate bonding and a liquid crystal dropping process . In the repair process, a repair process for defective signal wiring and TFT defects determined to be repairable by the inspection process is performed.

The module assembly process is a process of assembling the liquid crystal display panel and the backlight unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Referring to FIG. 8, in the liquid crystal display of the present invention, the display panel includes substrates 10 and 19 having a hydrophobic surface in the margin region MAR, and a liquid crystal layer 16 formed between the substrates.

Each of the first and second substrates 10 and 19 is made of a substrate of a transparent material. A polarizing plate (not shown) is bonded to each of the substrates 10 and 19. On the surfaces of the substrates 10 and 19 which are in contact with the liquid crystal layer 16, an alignment film PI for setting the pretilt angle of the liquid crystal molecules is formed. On the upper substrate 10, an upper alignment layer PI which is not overlapped with the encapsulant 50 is formed. A lower alignment film PI is formed on the lower substrate 19 so as not to overlap with the encapsulant 50. The alignment film PI is hardly formed in the margin region MAR due to the hydrophobic surface of the margin region MAR.

The display panel is divided into an active area A / A in which an image is displayed and a bezel area outside the active area A / A. The bezel region is divided into a margin region MAR where the substrates 10 and 19 are bonded together using a sealant 50 and a pad region (not shown) (Fig. 6, PAD).

The active area A / A includes a pixel array. The pixel array includes a TFT array formed on the lower substrate 19 and a color filter array formed on the upper substrate 10. [ The TFT array includes data lines, gate lines intersecting with data lines, data lines and gate lines, TFTs formed at intersections of data lines and gate lines, pixel electrodes connected to TFTs, and storage capacitors Storage Capacitor, Cst) and the like. The color filter array includes red, green, and blue color filters 12 for color implementation, and a black matrix 11. In the COT (Color Filter On TFT) process, the color filter 12 and the black matrix 11 may be formed on the lower substrate 19. The common electrode may be formed on the upper substrate 10 or the lower substrate 19.

Spacers are formed on the display panel. The spacers include a first spacer 15 formed in the active array region A / D, spacers 14a and 14b formed in the margin region MAR and having a hydrophobic surface (hereinafter referred to as "hydrophobic spacer & The spacers 15 of the region A / A are formed at a height that maintains the cell gap of the liquid crystal layer 16.

The hydrophobic spacers 14a and 14b include a first hydrophobic spacer 14a formed between the active area A / A and the encapsulant 50 and a second hydrophobic spacer 14b superimposed on the encapsulant 50 do. The first hydrophobic spacer 14a may be formed at substantially the same height as the first spacer 15. The first hydrophobic spacer 14a does not overlap with the encapsulant 50. The first hydrophobic spacer 14a has a hydrophobic surface on which the alignment film solution is not well coated and serves as a dam preventing the diffusion of the alignment film solution. The second hydrophobic spacer 14b is formed at a lower height than the second spacer 14a so that the sealant 50 can be applied to a sufficient thickness. The second hydrophobic spacer 14b has a hydrophobic surface on which the alignment film solution is not well coated.

The spacers 15, 14a and 14b are formed by forming a photosensitive resin on the overcoat layer 13 used as a planarizing film, aligning a halftone mask on the photosensitive resin, May be simultaneously formed by a photolithography process for exposing and developing the photosensitive resin. The photosensitive resin may be photo-acryl. The overcoat layer 13 may be formed of acrylic.

In the margin region MAR, the hydrophobic patterns 17a and 17b are formed on the lower substrate 19. The hydrophobic patterns 17a and 17b are formed by a first hydrophobic pattern 17a formed between the active area A / A and the encapsulant 50 and a second hydrophobic pattern 17b overlapped with the encapsulant 50 . The first hydrophobic pattern 17a has a hydrophobic surface on which the alignment film solution is not well coated and serves as a dam preventing diffusion of the alignment film solution. The second hydrophobic patterns 17b have a hydrophobic surface on which the alignment film solution is not well coated. The sealant 50 adheres to the second hydrophobic patterns 17b so as to be adhered to the substrate 19 and also directly to the substrate 19 between the second hydrophobic patterns 17b.

The surface treatment methods of the hydrophobic spacers 14a and 14b and the hydrophobic patterns 17a and 17b are as shown in FIGS. The hydrophobic polymer is uniformly dispersed in the photosensitive resin and applied to the substrate or the overcoat layer as shown in Fig. 9 (A), and then the photosensitive resin is heated at a soft-baking temperature of a predetermined temperature at which the photosensitive resin is not completely cured. At the soft baking temperature, the hydrophobic polymer moves to the surface of the photosensitive resin as shown in Fig. 9 (B). Next, the present invention carries out a photolithography process. Then, hydrophobic spacers 14a and 14b and hydrophobic patterns 17a and 17b of a desired shape are formed on the substrates 10 and 19 as shown in Fig. 9 (C). The hydrophobic polymer is cross-linked with the photosensitive resin molecules. The hydrophobic polymer may be any of a fluorine-based polymer and a silicone-based polymer or a known hydrophobic polymer material.

10 to 12 show a method of forming the hydrophobic spacers 14a and 14b and the hydrophobic patterns 17a and 17b using the irregular surface of the nanostructure.

10 to 12, the present invention forms a micro concave / convex surface on a substrate 60. A number of fine holes 60a are formed on the surface of the micro concavo-convex portion.

The micro concavo-convex surface has a hydrophobic property by increasing the contact angle? In Fig. 12. A hydrophobic substance may be formed on the micro concavo-convex surface. The micro concavo-convex surface can be formed on the substrate 60 by a laser processing method or a photolithography method. The substrate 60 may be the substrate 10, 19 shown in FIG. 8 or may be adhered to the surface of the substrate 10, 19. Since the micro-irregular surface can realize a super water-repellent surface, there is no need to necessarily form a hydrophobic material on the surface.

Regarding the super water-repellent surface characteristics of the micro concavo-convex surface, KIC News, Vol. 10 and 11, the micro-irregularity structure can be formed in various forms such as a honeycomb, a stripe, and a lattice, as shown in Figs. 10 and 11. [ As shown in FIG.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

20: printing plate 21: printing roller
22: Anilox roller 23: Orientation film solution
24: Dr. Blade 25: Dispenser
26: Doctor roller 30: PI mount

Claims (11)

1. A liquid crystal display comprising an active region and a margin region,
A first substrate including a spacer formed in the active region and a hydrophobic spacer formed in the margin region and having a first alignment layer;
A second substrate including hydrophobic patterns formed in the margin region and having a second alignment layer formed thereon;
A liquid crystal layer formed between the first and second substrates in the active region and the margin region; And
And a sealant formed on the margin region to bond the first and second substrates together. The method according to claim 1,
The hydrophobic spacer comprises:
A first hydrophobic spacer formed between the active region and the sealant; And
And a second hydrophobic spacer overlapped with the sealant. 3. The method of claim 2,
Wherein the second hydrophobic spacer has a lower height than the first hydrophobic spacer. 4. The method according to any one of claims 1 to 3,
Wherein the hydrophobic spacer and the surface of the hydrophobic patterns include a hydrophobic polymer. 4. The method according to any one of claims 1 to 3,
And the surface of the hydrophobic spacer and the hydrophobic patterns include micro-irregularities. 4. The method according to any one of claims 1 to 3,
Wherein the sealant and the alignment layer do not overlap each other. 1. A liquid crystal display comprising an active region and a margin region,
Forming spacers and a first alignment layer on a first substrate;
Forming hydrophobic patterns and a second alignment layer on a second substrate;
Forming an encapsulant in a margin region of one of the first and second substrates and forming a liquid crystal layer between the first and second substrates; And
And bonding the first and second substrates with the encapsulant,
The spacers,
A spacer formed in the active region,
And hydrophobic spacers formed in the margin region,
Wherein the hydrophobic patterns are formed in the margin region. 8. The method of claim 7,
The hydrophobic spacers,
A first hydrophobic spacer formed between the active region and the sealant; And
And a second hydrophobic spacer overlapped with the sealant,
Wherein the second hydrophobic spacer has a lower height than the first hydrophobic spacer,
Wherein the first and second hydrophobic spacers are formed at the same time. 9. The method according to claim 7 or 8,
Wherein the hydrophobic spacer and the surface of the hydrophobic patterns include a hydrophobic polymer. 9. The method according to claim 7 or 8,
Wherein the hydrophobic spacer and the surface of the hydrophobic patterns include micro-irregularities. 9. The method according to claim 7 or 8,
4. The method according to any one of claims 1 to 3,
Wherein the sealant and the alignment layer do not overlap each other.

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