KR20070071539A - Flat plate display device and the fabrication method - Google Patents

Abstract

A flat display device and a method for manufacturing the same are provided to produce a uniformly polymerized high-quality polymer thin film, by using a polymer precursor material containing a photo-initiator. A flat display device comprises a first substrate(132), a second substrate(102), and a liquid crystal layer between the first substrate and the second substrate. Driving elements are formed above the first substrate. A planarization layer(107) and a spacer(113) are formed above the first substrate or the second substrate. The planarization layer is formed of a polymer precursor material containing at least one photo-initiator.

Description

Flat plate display device and the fabrication method

1 is a cross-sectional view showing a liquid crystal display panel of the conventional IPS mode.

2A to 2F are cross-sectional views illustrating a method of manufacturing an upper array substrate of a conventional liquid crystal display panel in steps.

3 is a cross-sectional view showing a liquid crystal display panel in IPS mode according to the present invention.

4A to 4C are flowcharts illustrating a process of manufacturing an upper substrate of a liquid crystal display panel according to the present invention.

5 is a graph showing the calorific value according to the roughness of the liquid polymer precursor material using the dual photoinitiator according to the present invention.

6 is a DSC graph of a liquid polymer precursor using a dual photoinitiator and a liquid polymer precursor using a mono photoinitiator as a control.

<Description of Signs of Major Parts of Drawings>

102: upper substrate 104: black matrix

118: common electrode 132: lower substrate

106: color filter 107: flattening layer

134: Soft mold 113: spacer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display, and more particularly, to a flat panel display and a method of manufacturing the same, wherein the thin film pattern uniformly polymerized is formed by a non-exposure method.

In general, a liquid crystal display (LCD) displays an image corresponding to a video signal on a liquid crystal display panel in which liquid crystal cells are arranged in a matrix form by adjusting light transmittance of liquid crystal cells according to a video signal. To this end, the liquid crystal display includes a liquid crystal display panel in which liquid crystal cells are arranged in an active matrix, and driving circuits for driving the liquid crystal display panel.

Such liquid crystal displays are roughly classified into twisted nematic (TN) mode and in plan switch (IPS) mode using a vertical electric field according to the electric field driving the liquid crystal.

The TN mode is a mode in which a liquid crystal is driven by a vertical electric field between a pixel electrode and a common electrode arranged to face the upper substrate. The TN mode has an advantage that the aperture ratio is large while the viewing angle is folded. The IPS mode is a mode in which a liquid crystal is driven by a horizontal electric field between a pixel electrode and a common electrode disposed side by side on a lower substrate, and has a large viewing angle, but a small aperture ratio.

1 is a cross-sectional view showing a liquid crystal display panel of a conventional IPS mode.

Referring to FIG. 1, the liquid crystal display panel of the IPS mode has a black matrix 4, a color filter 6, and a planarization sequentially formed on an upper substrate 2 having a transparent electrode layer 3 thereon to prevent static electricity and the like on the back side. An upper array substrate (or color filter array substrate) composed of a layer 7, a spacer 13, and an upper alignment layer 8, and a thin film transistor (hereinafter referred to as “TFT”) formed on the lower substrate 32 in common. Liquid crystal (not shown) injected into an inner space between the lower array substrate (or thin film transistor array substrate) composed of the electrode 18, the pixel electrode 16 and the lower alignment layer 38, and the upper array substrate and the lower array substrate. ).

In the upper array substrate, the black matrix 4 is formed to overlap the TFT region of the lower substrate 2 with the gate line and data line regions (not shown) and partitions the cell region where the color filter 6 is to be formed. . The black matrix 4 serves to prevent light leakage and to increase contrast by absorbing external light. The color filter 6 is formed in the cell region separated by the black matrix 4. The color filter 6 is formed for each of R, G, and B to implement R, G, and B colors. The planarization layer 7 is formed to cover the color filter to planarize the upper substrate 2. The column spacer 13 maintains a cell gap between the upper substrate 2 and the lower substrate 32.

In the lower array substrate, the TFT overlaps the gate electrode 9 formed on the lower substrate 32 with the gate line (not shown), and the gate electrode 9 and the gate insulating film 44 interposed therebetween. The semiconductor layers 14 and 47 and the source / drain electrodes 40 and 42 formed together with the data lines (not shown) with the semiconductor layers 14 and 47 interposed therebetween. This TFT supplies a pixel signal from the data line to the pixel electrode 16 in response to a scan signal from the gate line. The pixel electrode 16 is a transparent conductive material having high light transmittance and is in contact with the drain electrode 42 of the TFT with the protective film 50 therebetween. The common electrode 18 is formed in a stripe shape so as to alternate with the pixel electrode 16. The common electrode 18 supplies a common voltage which is a reference when driving the liquid crystal. The liquid crystal rotates with respect to the horizontal direction by the horizontal electric field between the common voltage and the pixel voltage supplied to the pixel electrode 16.

The upper and lower alignment layers 8 and 38 for liquid crystal alignment are formed by applying an alignment material such as polyimide and then performing a rubbing process.

2A through 2F are cross-sectional views illustrating a method of manufacturing an upper array substrate of a conventional liquid crystal display panel.

First, the transparent conductive layer 3 is formed on the back surface of the upper substrate 2 by a deposition method such as sputtering. Subsequently, after the opaque resin is applied to the entire surface of the upper substrate 2, the black matrix 4 is formed as shown in FIG. 2A by patterning the photolithography process and the etching process using the first mask. Here, chromium (Cr) or the like may be used as the black matrix 4 material.

After the red resin is deposited on the upper substrate 2 on which the black matrix 4 is formed, the red resin R is patterned by a photolithography process and an etching process using a second mask, thereby providing red color as shown in FIG. 2B. The color filter R is formed.

After the green resin is deposited on the upper substrate 2 on which the red color filter R is formed, the green resin is patterned by a photolithography process and an etching process using a third mask, thereby displaying the green color filter as shown in FIG. 2C. (G) is formed. After the blue resin is deposited on the upper substrate 2 on which the green color filter G is formed, the blue resin is patterned by a photolithography process and an etching process using a fourth mask, so that the blue color filter as shown in FIG. 2D. By forming (B), the red, green and blue color filters 6 are formed.

The organic material is entirely deposited on the upper substrate 2 on which the red, green, and blue color filters 6 are formed, thereby forming the planarization layer 7 as shown in FIG. 2E. The planarization layer 7 prevents the phenomenon of disclination due to the step generated by the black matrix 2 formed of the opaque resin.

After the spacer material is deposited on the upper substrate 2 on which the planarization layer 7 is formed, the spacer material is patterned by a photolithography process and an etching process using a fifth mask, so that the column spacer 13 is shown in FIG. 2F. ) Is formed.

As described above, in order to form the upper array substrate of the conventional liquid crystal display panel, at least five or more mask processes are required. Each mask process includes a photolithography process and the photolithography process is a series of photographic processes including application of photoresist, mask alignment, exposure and development. The photolithography process requires a long process time, a large waste of photoresist and a developer for developing a photoresist pattern, and requires expensive equipment such as an exposure apparatus. As a result, the manufacturing process is complicated and there is a problem of increasing the manufacturing cost of the liquid crystal display panel.

The present invention provides a flat display capable of obtaining a high-quality polymer thin film uniformly polymerized using a photocurable polymer precursor including a dual photoinitiator having a wide range of illuminance having an optimized degree of polymerization and having a large UV cure margin. It is an object to provide an apparatus and a method of manufacturing the same.

In order to achieve the above object, a flat panel display device according to the present invention, the first substrate and the second substrate; A drive element formed on the first substrate; And a planarization layer and a spacer formed of a polymer precursor material including at least one photoinitiator on the first substrate or the second substrate.

A lower portion of the planarization layer and the spacer may include a black matrix and a color filter formed in a region partitioned by the black matrix.

The planarization layer and the spacer is characterized in that formed by pressing the soft mold.

According to an aspect of the present invention, there is provided a method of manufacturing a flat panel display, including: forming a liquid polymer precursor including a resin, a binder, and at least two kinds of photoinitiators on a substrate; Pressing the liquid polymer precursor with a soft mold to transfer the soft mold pattern to the liquid polymer precursor to form the soft mold pattern; Photocuring the molded liquid polymer precursor to form a polymer thin film; And separating the soft mold from the polymer thin film.

Forming a black matrix on the substrate; The method may further include forming a color filter in a region partitioned by the black matrix.

The polymer thin film is formed of a planarization layer and a spacer on the substrate.

In the step of photocuring the molded liquid polymer precursor to form a polymer thin film, the liquid polymer precursor is characterized in that the polymer polymerization degree is the same in a predetermined light intensity range.

The photoinitiator is characterized by using a mixture of a ketone-based photoinitiator and a phosphine oxide-based photoinitiator.

The ketone-based photoinitiator is characterized in that it comprises Irgacure 184, Irgacure 651, Irgacure 369, Irgacure 907.

The phosphine oxide-based photoinitiator is characterized in that it comprises Irgacure 819.

Hereinafter, a liquid crystal display device manufactured by a process including at least one process of patterning the non-exposure method according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a cross-sectional view illustrating a liquid crystal display panel in an IPS mode according to the present invention.

The liquid crystal display panel of the IPS mode shown in FIG. 3 is a black matrix 104, a color filter 106, and a planarization layer sequentially formed on the upper substrate 102 having the transparent electrode layer 103 on the back side to prevent static electricity. 107, an upper array substrate (or color filter array substrate) composed of a spacer 113 and an upper alignment layer 108, a thin film transistor (hereinafter referred to as "TFT") formed on the lower substrate 132, and a common electrode 118, a lower array substrate (or a thin film transistor array substrate) including a pixel electrode 116 and a lower alignment layer 138, and a liquid crystal (not shown) injected into an internal space between the upper array substrate and the lower array substrate. It is provided.

In the upper array substrate, the black matrix 104 is formed to overlap the TFT region of the lower substrate 132 and the gate line and data line regions (not shown) and partitions a cell region in which the color filter 106 is to be formed. . The black matrix 104 prevents light leakage and absorbs external light to increase contrast. The color filter 106 is formed in the cell region separated by the black matrix 104. The color filter 106 is formed for each of R, G, and B to implement various colors when driving the liquid crystal.

The planarization layer 107 is formed to cover the color filter 106 to planarize the upper substrate 102. The column spacer 113 serves to maintain a cell gap between the upper substrate 102 and the lower substrate 132.

The planarization layer 107 and the column spacer 113 are simultaneously formed by a press molding method using a soft mold (not shown). Here, as the planarization layer 107 and the column spacer 113, a liquid pre-polymer curable by light (UV) is used.

The soft mold is made of relatively high elastic polydimethylsiloxane (PDMS), polyurethane (Polyurethane), cross-linked Novolac Resin (Cross-linked Novolac Resin).

The liquid polymer precursor (liquid pre-polymer) basically consists of a composition containing a basic resin, a binder, and a photo-initiator.

The base resin is poly ethylene glycol (Poly Ethylene Glycol (PEG)) is used as a material that can generate a repulsive force in contact with the soft mold. This polyethylene glycol (PEG) has good transparency as the coloration degree (APHA) is 20 or less. Accordingly, even when used as the planarization layer material, the transmittance is not lowered as compared with the prior art.

As the binder, a styrene-acrylic comonomer having styrene co-monomer added to an acrylic monomer may be used.

The liquid polymer precursor (liquid pre-polymer), such as by pressing the soft mold to form a spacer and a planarization layer at the same time. Accordingly, the manufacturing process is simplified and the manufacturing cost is reduced as compared with the related art.

In addition, the photoinitiator uses a dual photoinitiator to secure a transmittance and to enable photopolymerization exhibiting uniform thin film properties. When the photoinitiator is photocured in the soft mold contact state, a thin film having the same polymer polymerization degree can be obtained.

The dual photoinitiator is used by mixing a ketone-based photoinitiator and a phosphine oxide-based photoinitiator.

The ketone-based photoinitiators include Irgacure 184, Irgacure 651, Irgacure 369, Irgacure 907, and the like, and phosphine oxide-based photoinitiators include Irgacure 819.

A process of manufacturing the color filter substrate according to the present invention will be described in detail with reference to FIGS. 4A to 4C as follows.

First, a liquid pre-polymer material 107a is coated on the upper substrate 102 on which the color filter 106 is formed by a coating method such as a nozzle or spin coating as shown in FIG. 4A. .

The liquid polymer precursor material 107a includes a dual photoinitiator in which a ketone-based photoinitiator and a phosphine oxide-based photoinitiator are mixed, a basic resin, and a binder material.

Here, the liquid polymer precursor is applied to have a predetermined thickness in consideration of the height of the planarization layer and the spacer. For example, when designing a spacer having a height of about 4 μm and a planarization layer of about 2 μm, the liquid polymer precursor 107a material is applied to have a thickness of about 6 μm.

In addition, the soft mold 134 having the groove 134a and the protrusion 134b is aligned with the liquid polymer precursor material 107a as illustrated in FIG. 4B. The groove 134a of the soft mold 134 corresponds to the region where the spacer is to be formed. The soft mold 134 may be made of a highly elastic rubber material such as poly dimethyl siloxane (PDMS), polyurethane, cross-linked Novolac Resin, or the like. .

The soft mold 134 has a weight of its own weight for a predetermined time on the liquid polymer precursor material 107a so as to contact the surface of the protrusion 134b of the soft mold 134, the color filter 106, and the black matrix 104. While pressurized.

At the same time, 350 nm to 370 nm ultraviolet (UV) light is transmitted through the soft mold 134 to the liquid polymer precursor material 107a by the exposure apparatus, or transmitted through the upper substrate 31 and the thin films. 107a) is investigated. Then, the liquid polymer precursor material 107a is caused by capillary force generated by the pressure between the soft mold 134 and the upper substrate 102 and the repulsive force between the soft mold 134 and the liquid polymer precursor material 107a. ) Moves into the intaglio pattern 134a of the soft mold 134 as shown in FIG. 4C. At the same time, as the polymer network is formed in the liquid polymer precursor material 107a by the photopolymerization reaction of the liquid polymer precursor material 107a, the liquid polymer precursor material 107a isolated in the intaglio pattern 134a of the soft mold 134 is solidified. do.

As a result, the planarization layer 107 and the spacer 113 are simultaneously formed on the upper substrate 102.

As described above, the liquid crystal display panel and the method of manufacturing the same according to the present invention form the liquid polymer precursor material on the substrate on which the color filter is formed, and then press-molded with the soft mold 134 to form the spacer 113 and the planarization layer 107. To form.

Here, the polymer precursor material is made of a composition containing a basic resin, a binder, and a photo-initiator.

The base resin is poly ethylene glycol (Poly Ethylene Glycol (PEG)) is used as a material that can generate a repulsive force in contact with the soft mold. This polyethylene glycol (PEG) has good transparency as the coloration degree (APHA) is 20 or less.

As the binder, a styrene-acrylic comonomer to which an styrene co-monomer is added to an acrylic monomer may be used.

In addition, the photoinitiator uses a dual photoinitiator to secure a transmittance and to enable photopolymerization exhibiting uniform thin film properties. When the photoinitiator is photocured in the soft mold contact state, a thin film having the same polymer polymerization degree can be obtained.

The dual photoinitiator is used by mixing a ketone-based photoinitiator and a phosphine oxide-based photoinitiator.

The ketone-based photoinitiators include Irgacure 184, Irgacure 651, Irgacure 369, Irgacure 907, and the like, and phosphine oxide-based photoinitiators include Irgacure 819.

Hereinafter, the characteristics of the dual photoinitiator according to the present invention will be described in detail.

5 is a graph showing the calorific value according to the roughness of the liquid polymer precursor material using the dual photoinitiator according to the present invention.

The liquid polymer precursor material is a first region in which the calorific value (unit; J / g) gradually increases according to the illuminance (unit; mW / cm 2), the second region having a constant calorific value in the illuminances a to b, and inversely above the constant illuminance b. There is a third region in which the calorific value gradually decreases.

Here, the first region refers to a state in which the curing of the liquid polymer is less performed at low roughness, and the properties of the polymer-polymerized thin film are not uniform.

In addition, the second region has a uniform calorific value at roughness having a range of a to b, which indicates that the polymer polymerization degree of the liquid polymer precursor material is the same even if the light intensity is increased within the range, and that the properties of the polymer-polymerized thin film are uniform. Able to know.

In addition, the third region is in an over-cured state exceeding the limit of roughness for the liquid polymer precursor material, and the polymer polymerization of the thin film is broken, thereby degrading the polymer properties.

Therefore, the wider the range of the second region can form a thin film having a uniform characteristic with the same degree of polymerization at any roughness in the region, and the light treatment margin can be widened to ensure the ease of the process.

The dual photoinitiator used in the present invention has a large area of the second region having a constant calorific value with respect to a predetermined illuminance range, and refer to [Table 1] and [Table 2] below.

[Table 1] shows the calorific value according to the illuminance using the dual photoinitiator, [Table 2] shows the calorific value according to the illuminance using the mono photoinitiator.

Therefore, as shown in Table 1, in the case of the dual photoinitiator according to the present invention, when the illuminance is 5 mW / ㎠, 11 mW / ㎠, 20 mW / ㎠, each of the calorific value is 482 J / g, 483 J / It can be seen that the calorific value is constant as g, 486 J / g.

In this case, the dual photoinitiator is used by mixing a ketone-based photoinitiator and a phosphine oxide-based photoinitiator, the ketone-based photoinitiator includes Irgacure 184, Irgacure 651, Irgacure 369, Irgacure 907, The phosphine oxide-based photoinitiator is selected from Irgacure 819.

And, as shown in Table 2, when the mono photoinitiator was used as a control of the present invention, when the illuminance is 5 mW / ㎠, 11 mW / ㎠, 20 mW / ㎠, each calorific value is 133 J / g, 190 It turns out that a calorific value rises rapidly as J / g and 360 J / g.

That is, the liquid polymer precursor material using the mono photoinitiator as a control should be photopolymerized in a state in which the soft mold is in contact with the coated state. Although it is difficult to form a polymer thin film having a degree of polymerization, the liquid polymer precursor material using the dual photoinitiator according to the present invention has a margin for obtaining a uniform degree of polymerization upon light curing by pressing with a soft mold in a coated state. Kerr to form a polymer thin film having a uniform degree of polymerization over the entire surface of the liquid polymer precursor material.

6 is a DSC graph of the liquid polymer precursor using the dual photoinitiator according to the present invention and the liquid polymer precursor using the mono photoinitiator as a control, and [Table 3] is a measurement result table based on the graph of FIG. 6.

Referring to Figure 6, it shows the calorific value of the polymer polymerization of the liquid polymer precursor according to the roughness, measured using a first dual photoinitiator, a second dual photoinitiator, a first mono photoinitiator, a second mono photoinitiator [ Table 3].

Accordingly, in the case of the dual photoinitiator, it is possible to obtain a polymer thin film having the same characteristics between 3 mW / cm 2 and 50 mW / cm 2, so that the light intensity margin section having the same polymer polymerization degree is large.

As a result, the present invention has an advantage in that the light intensity margin having a uniform polymer thin film characteristic has a large width even though a small amount of a photoinitiator is used in the process of pressing and curing the liquid polymer precursor material with a soft mold.

As described above, a flat panel display device in which a spacer and a planarization layer are simultaneously formed by a soft mold using a liquid polymer precursor material using a dual photoinitiator having a large light intensity margin according to the present invention is a liquid crystal display panel and a TN mode in IPS mode. In addition to the liquid crystal display panel of the present invention, it can be easily applied to the liquid crystal display panel of ECB (Electrical Controlled Birefringence), and also VA (Vertical Alignment) mode.

Although the present invention has been described in detail through specific embodiments, this is for describing the present invention in detail, and the flat panel display device and the manufacturing method thereof according to the present invention are not limited thereto. It is apparent that modifications and improvements are possible to those skilled in the art.

In the process of non-exposure patterning in a liquid crystal display device, the light illuminance having uniform polymer thin film characteristics even with a small amount of photoinitiator in the process of pressing and curing the liquid polymer precursor material by soft mold patterning Large margin width for easy process

Claims (13)

A first substrate and a second substrate; A drive element formed on the first substrate; And a planarization layer and a spacer formed of a polymer precursor material including at least one photoinitiator on the first substrate or the second substrate. The method of claim 1, And a black matrix and a color filter formed in a region partitioned by the black matrix below the planarization layer and the spacer. The method of claim 1, And the planarization layer and the spacer are formed by pressing by a soft mold. The method of claim 1, The photoinitiator is a flat panel display, characterized in that used by mixing a ketone-based photoinitiator and a phosphine oxide-based photoinitiator. The method of claim 1, The ketone-based photoinitiator includes Irgacure 184, Irgacure 651, Irgacure 369, Irgacure 907. The method of claim 1, And the phosphine oxide-based photoinitiator includes Irgacure 819. Forming a liquid polymer precursor comprising a resin, a binder, and at least two kinds of photoinitiators on a substrate; Pressing the liquid polymer precursor with a soft mold to transfer the soft mold pattern to the liquid polymer precursor to form the soft mold pattern; Photocuring the molded liquid polymer precursor to form a polymer thin film; And separating the soft mold from the polymer thin film. The method of claim 7, wherein Forming a black matrix on the substrate; And forming a color filter in a region partitioned by the black matrix. The method of claim 7, wherein The polymer thin film is a flat panel display manufacturing method, characterized in that formed on the substrate and a spacer. The method of claim 7, wherein In the step of photocuring the molded liquid polymer precursor to form a polymer thin film, And the liquid polymer precursor has the same polymer polymerization degree in a predetermined light intensity range. The method of claim 7, wherein The photoinitiator is a method of manufacturing a flat panel display device, characterized in that a ketone-based photoinitiator and a phosphine oxide-based photoinitiator is mixed and used. The method of claim 7, wherein The ketone-based photoinitiator comprises Irgacure 184, Irgacure 651, Irgacure 369, Irgacure 907, the manufacturing method of the flat panel display device. The method of claim 7, wherein The phosphine oxide-based photoinitiator manufacturing method of a flat panel display device comprising Irgacure 819.

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