KR20060029408A - Transverse electric field type liquid crystal display device and manufacturing method thereof - Google Patents

Abstract

To provide a liquid crystal display device having a transverse electric field system (IPS) suitable for securing excellent optical density (OD) and contrast ratio (CR) characteristics, and a manufacturing method thereof. A liquid crystal display device of a transverse electric field method (IPS) for achieving the object includes a lower substrate having a pixel region defined therein and including a common electrode and a pixel electrode to drive the transverse electric field; A black matrix layer formed of a metallic material on an upper portion except the portion corresponding to the pixel region, a color filter layer formed on a portion corresponding to the pixel region, and an insulating film on the entire surface including the black matrix layer and the color filter layer; An upper substrate bonded to the lower substrate and having a predetermined space; The liquid crystal layer is injected between the upper and lower substrates.

Black matrix, metal, insulating film

Description

Transverse electric field type liquid crystal display device and its manufacturing method {LIQUID CRYSTAL DISPLAY DEVICE OF IN-PLANE SWITCHING AND METHOD FOR FABRICATING THE SAME}

1 is an exploded perspective view showing a part of a typical TN liquid crystal display device

2 is a structural cross-sectional view taken along line II ′ of FIG. 1;

3 is a schematic structural cross-sectional view of a liquid crystal display device of a transverse electric field method (IPS) according to an embodiment of the present invention

4A to 4F are cross-sectional views illustrating a method of manufacturing an upper substrate of a transverse electric field type liquid crystal display device according to the present invention.

Explanation of symbols on the main parts of the drawings

70: lower substrate 71: common electrode

72: gate insulating film 73: data line

74: protective film 75: pixel electrode

80: upper substrate 81: metal material

81a: black matrix layer 82: photosensitive film

83a, 83b, 83c: R, G, B color filter layer 84: insulating film

100: transparent conductive film

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a transverse electric field type liquid crystal display device and a method of manufacturing the same, which are suitable for securing optical density (OD) and contrast ratio (CR) characteristics.

As the information society develops, the demand for display devices is increasing in various forms, and in recent years, liquid crystal displays (LCDs), plasma display panels (PDPs), electro luminescent displays (ELDs), and vacuum fluorescent displays (VFDs) 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, development of high quality images such as high definition, high brightness, and large area is maintained while maintaining the characteristics of light weight, thinness, and low power consumption. It can be said.

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 lines arranged in one direction at a predetermined interval, a plurality of data lines arranged at regular intervals in a direction perpendicular to the gate lines, and A plurality of pixel electrodes formed in a matrix form in each pixel region defined by crossing each gate line and data line, and a plurality of thin films that transmit signals of the data line to each pixel electrode by being switched by signals of the gate line The transistor 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, B color filter layer for expressing color colors, and a common electrode for implementing an image. Is formed. Of course, the common electrode is formed on the first glass substrate in the transverse electric field type liquid crystal display device.

The first and second glass substrates are bonded by a sealing material having a predetermined space by a spacer and having a liquid crystal injection hole, and a liquid crystal is injected between the two substrates.

In this case, in the liquid crystal injection method, the liquid crystal is injected between the two substrates by osmotic pressure when the liquid crystal injection hole is immersed in the liquid crystal container by maintaining the vacuum state between the two substrates bonded by the seal material. When the liquid crystal is injected as described above, the liquid crystal injection hole is sealed with a sealing material.

On the other hand, the driving principle of the liquid crystal display device as described above uses the optical anisotropy and polarization of the liquid crystal.

Since the liquid crystal is thin and long in structure, the liquid crystal has a direction in the arrangement of molecules, and the liquid crystal may be artificially applied to control the direction of the molecular arrangement.

Accordingly, when the molecular arrangement direction of the liquid crystal is arbitrarily adjusted, the molecular arrangement of the liquid crystal is changed, and light polarized by optical anisotropy may be arbitrarily modulated to express image information.

Such liquid crystals may be classified into positive liquid crystals having a positive dielectric anisotropy and negative liquid crystals having a negative dielectric anisotropy according to an electrical specific classification, and liquid crystal molecules having a positive dielectric anisotropy are long axes of liquid crystal molecules in a direction in which an electric field is applied. The liquid crystal molecules arranged in parallel and having negative dielectric anisotropy are arranged perpendicularly to the direction in which the electric field is applied and the major axis of the liquid crystal molecules.

1 is an exploded perspective view showing a part of a general TN liquid crystal display device, and FIG. 2 is a structural cross-sectional view taken along line II ′ of FIG. 1.

1 and 2, the lower substrate 1 and the upper substrate 2 bonded to each other with a predetermined space, and the liquid crystal layer 3 injected between the lower substrate 1 and the upper substrate 2. )

More specifically, the lower substrate 1 has a plurality of gate lines 4 arranged in one direction at regular intervals to define the pixel region P, and the gate electrode 4 is disposed on one side of the gate line 4. 4a) is formed to protrude, and a gate insulating film 10 is formed on the entire lower substrate 1 including the gate line 4. The active pattern 11 is formed on the gate insulating film 10 including the gate electrode 4a. A plurality of data lines 5 are arranged at regular intervals in a direction perpendicular to the gate line 4, and a source electrode 5a is formed to overlap one side of the gate electrode 4a. A drain electrode 5b is formed to be spaced apart from the source electrode 5a so as to overlap the upper portion of the gate electrode 4a. In this case, an ohmic contact layer 11a may be further formed between the active pattern 11 and the source electrode 5a and between the active pattern 11 and the drain electrode 5b. An insulating layer 13 is formed on the entire surface of the lower substrate 1 including the data line 5 to have the contact hole 12 in one region of the drain electrode 5b. The gate line 4 and the data line The pixel electrode 6 is formed in each pixel region P where (5) intersects with the drain electrode 5b through the contact hole 12. The thin film transistor T is formed at a portion where the gate lines 4 and the data lines 5 cross each other.

The upper substrate 2 includes a black matrix layer 7 for blocking light in portions other than the pixel region P, an R, G, and B color filter layer 8 for expressing color colors, and an image. The common electrode 9 is formed to implement the.

The thin film transistor T is formed on the gate electrode 4a protruding from the gate line 4, the gate insulating film 10 formed on the front surface, and the gate insulating film 10 on the gate electrode 4a. The active pattern 11 includes a source electrode 5a protruding from the data line 5, and a drain electrode 5b spaced apart from the source electrode 5a.

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

In the liquid crystal display device configured as described above, the liquid crystal layer 3 positioned on the pixel electrode 6 is aligned by a signal applied from the thin film transistor T, and the liquid crystal layer 3 is aligned with the alignment degree of the liquid crystal layer 3. Accordingly, the image can be expressed by controlling the amount of light passing through the liquid crystal layer 3.

The TN liquid crystal display device as described above has a disadvantage in that the viewing angle characteristic is not excellent in a manner of driving the liquid crystal by an electric field applied up and down.

The present invention has been made to solve the above problems, an object of the present invention is excellent transverse angle field, and is suitable for securing the optical density (OD) and contrast ratio (CR) characteristics of the transverse electric field The present invention provides a liquid crystal display (IPS) and a method of manufacturing the same.

According to an aspect of the present invention, there is provided a liquid crystal display (IPS) of a transverse electric field system (IPS), the lower substrate including a common electrode and a pixel electrode to define a pixel area and to drive the transverse electric field; A black matrix layer formed of a metallic material on an upper portion except the portion corresponding to the pixel region, a color filter layer formed on a portion corresponding to the pixel region, and an insulating film on the entire surface including the black matrix layer and the color filter layer; An upper substrate bonded to the lower substrate and having a predetermined space; The liquid crystal layer is injected between the upper and lower substrates.

The black matrix layer is characterized by being composed of a metal material of Fe, Fe + FeOx, Cr, Cr + CrOx or CrOx + Cr + CrOx.

The insulating film is formed of an organic film or an inorganic film having a dielectric constant <3, transmittance> 95%, flatness> 90%, and hardness> 3H.

The insulating film is characterized in that it is formed to have a thickness of about 2㎛ or more.

The insulating film may further include an inorganic film of Al 2 O 3, O 2, SiN x, or SiO 2.

A plurality of gate lines and data lines intersecting and arranged in the lower substrate to define the pixel region, the common electrode and the pixel electrode alternately formed in each pixel region where the gate line and the data line cross each other, And a thin film transistor formed at a portion where the gate line and the data line cross each other.

In the method of manufacturing a transverse electric field type (IPS) liquid crystal display device of the present invention having the above configuration, a method of manufacturing a transverse electric field type liquid crystal display device including upper and lower substrates bonded to each other with a predetermined space having a pixel area defined therein. Forming a black matrix layer on the upper substrate except for the pixel region; Forming a color filter layer on an upper substrate corresponding to the pixel region; And forming an insulating film on the entire surface of the upper substrate.

A transparent conductive film is further formed on the rear surface of the upper substrate.

The black matrix layer may be formed by depositing a metal material on the entire surface of the upper substrate, applying a photoresist film on the metal material, and selectively patterning the photoresist film so that only one region remains in an exposure and development process. Etching the metal material with a mask, and removing the photoresist.

The metal material is formed of Fe, Fe + FeOx, Cr, Cr + CrOx or CrOx + Cr + CrOx.

The insulating film is characterized by using an inorganic film or an organic film having a dielectric constant &lt; 3, transmittance &gt; 95%, flatness &gt; 90%, and hardness &gt;

The insulating film is formed to have a thickness of 2㎛ or more.

The color filter layer may include forming R, G, and B color filter layers in each pixel region through a process of coating, exposing, and developing a color sensing material of R, G, and B on the upper substrate, respectively. It features.

Hereinafter, a liquid crystal display (IPS) of a transverse electric field system (IPS) according to a preferred embodiment of the present invention and a manufacturing method thereof will be described with reference to the accompanying drawings.

3 is a schematic cross-sectional view of a liquid crystal display device of a transverse electric field method (IPS) according to an embodiment of the present invention, Figures 4a to 4f is a manufacturing method of the upper substrate of the liquid crystal display device of a transverse electric field method according to the present invention The process cross section shown.

First, as shown in FIG. 3, a liquid crystal display (IPS) of a transverse electric field (IPS) according to an embodiment of the present invention includes a lower substrate 70 and an upper substrate 80 bonded to each other with a predetermined space and the lower substrate. It consists of a liquid crystal layer 90 injected between the substrate 70 and the upper substrate 80. A transparent conductive film 100 is formed on the rear surface of the upper substrate 80 to prevent static electricity.

More specifically, in the lower substrate 70, a plurality of gate lines are arranged in one direction with a predetermined interval to define the pixel region P, and a plurality of gate lines are arranged in a direction perpendicular to the gate line. The data line 73 is arranged, and in each pixel region P where the gate line and the data line 73 intersect, the common electrode 71 and the pixel electrode 75 are alternately formed. The thin film transistor is formed at the portion where the data lines 73 intersect.

In FIG. 3, the common electrode 71 is formed on the same layer as the gate line, and the pixel electrode 75 is formed on the passivation layer 74.

In addition to the configuration examples of the above-described IPS liquid crystal display device, it is possible to apply all the configurations of various IPS liquid crystal display devices for driving the transverse electric field.

The upper substrate 80 may include a black matrix layer 81a for blocking light except for the pixel region, R, G, and B color filter layers 83a, 83b, and 83c for expressing color colors; An insulating film 84 is formed over the entire upper substrate 80 including the black matrix layer 81a and the R, G, and B color filter layers 83a, 83b, and 83c.

The black matrix layer 81a is formed of a metal material, and the metal material may be Fe, Fe + FeOx, Cr, Cr + CrOx, or CrOx + Cr + CrOx.

Since the common electrode and the pixel electrode are formed on the lower substrate 70 and the transverse electric field is formed therebetween, the black matrix layer is formed on the upper substrate 80. Formation of material may interfere with transverse electric field driving. Therefore, typically, the black matrix layer is not formed of the metal material on the upper substrate 80.

However, when the black matrix layer is formed of a metal material, the optical density can be increased even though the deposition thickness is thin, thereby effectively blocking light.

In order to achieve the above effect, when the black matrix layer 81a is formed of a metal material on the upper substrate 80, the black matrix is formed so that a vertical electric field is not formed between the common electrode and the pixel electrode of the lower substrate 70. It is necessary to form an insulating film on the top including the layer 81a.

For the reason as described above, in the present invention, the insulating film 84 is formed on the R, G, B color filter layers 83a, 83b, 83c including the black matrix layer 81a.

At this time, the insulating film 84 is formed to have a dielectric constant <3, transmittance> 95%, flatness> 90%, hardness> 3H, and have a thickness of at least 2 μm.

If the insulating film 84 has the above characteristics, the insulating film 84 may use either an organic film or an inorganic film. In the case of forming the inorganic film, for example, Al2O3, O2, SiNx or SiO2 may be formed.

As a result, when the insulating film 84 having the above characteristics is formed on the upper substrate 80, even if the black matrix layer 81a of the upper substrate 80 is formed of a metal material, the transverse electric field of the lower substrate 70 is affected. It is possible to improve the light density and the flatness characteristics without giving.

Next, a method of manufacturing a liquid crystal display device of a transverse electric field system (IPS) according to an embodiment of the present invention having the above configuration will be described.

Hereinafter, a method of manufacturing an upper substrate among upper and lower substrates filled with liquid crystal will be described.

In the method of manufacturing a transverse electric field type liquid crystal display device according to an exemplary embodiment of the present invention, as shown in FIG. 4A, the transparent conductive film 100 is formed on the back surface of the upper substrate 80 by a sputtering process. In this case, the transparent conductive film 100 is formed to prevent static electricity and may be composed of ITO, ITZO, or IZO.

As shown in FIG. 4B, a metal material 81 is deposited on the upper substrate 80 by a sputtering process.

The metal material 81 may be composed of Fe, Fe + FeOx, Cr, Cr + CrOx or CrOx + Cr + CrOx.

Subsequently, as shown in FIG. 4C, the photoresist film 82 is coated on the metal material 81, and the photoresist film 82 is selectively patterned so that only one region remains in the exposure and development processes.

Next, as shown in FIG. 4D, the metal material 81 is etched using the selectively patterned photoresist layer 82 to form a black matrix layer 81a in one region, and the photoresist layer 82 is removed. In this case, the black matrix layer 81a is formed in an area except the pixel area of the lower substrate.

Subsequently, as shown in FIG. 4E, R, G, and B color filter layers 83a, 83b, and 83c are coated on the upper substrate 80 corresponding to each pixel region of the lower substrate through a coating process, an exposure process, and a development process. ) In turn.

For example, the R color filter material is coated on the upper substrate 80, and an R color filter layer 83a is formed in a predetermined pixel region through an exposure and development process, and then a G color sensor is coated and an exposure and development process is performed. Then, the G color filter layer 83b is formed in the predetermined pixel region, and then the B color sensor is coated, and the B color filter layer 83c is formed in the predetermined pixel region by an exposure and development process.

As described above, the R, G, and B color filter layers 83a, 83b, and 83c are formed through a coating process, an exposure process, and a developing process, respectively, and the R, G, and B color filter layers 83a, 83b, and 83c are formed. The method has been described using a color sensing material method of the pigment spraying method, for example, but may be formed using any one of a photo or printing process using a dye, a printing method using a pigment, an electrodeposition method or a transfer method.

Next, as shown in FIG. 4F, an insulating film 84 is deposited on the entire surface of the upper substrate 80.

The insulating film 84 is formed to have a dielectric constant <3, transmittance> 95%, flatness> 90%, hardness> 3H, and have a thickness of at least 2 μm. At this time, the insulating film 84 may be either an inorganic film or an organic film as long as it has the above characteristics, but preferably an organic film having insulating properties is used.

When the insulating film 84 having the above characteristics is deposited, the black matrix layer may be formed of a metal material on the upper substrate without affecting the transverse electric field of the lower substrate.

When the black matrix layer is formed of a metal material as described above, the flatness and liquid crystal alignment property of the color filter layer may be improved, and the unevenness of the thickness of the liquid crystal layer may be eliminated to prevent staining on the screen.

In addition, when the black matrix layer is formed of a metal material, the vertical pattern is possible, thereby improving the uniformity of the critical dimension (CD), and thus it is easy to secure the bonding margin when the upper and lower substrates are bonded. In this case, the CD target of the black matrix layer pattern may be within ± 1.0 μm.

In addition, since the fine pattern can be formed, the aperture ratio can be improved by approximately 5%.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the above embodiments, but should be defined by the claims.

The liquid crystal display of the transverse electric field method (IPS) of the present invention as described above and a manufacturing method thereof have the following effects.

First, by forming a black matrix layer made of a metal material having a high optical density (OD), high contrast ratio (CR) characteristics can be obtained.

Second, by forming the black matrix layer with a metal material, it is possible to improve the flatness and liquid crystal alignment of the color filter layer, and to eliminate the unevenness of the thickness of the liquid crystal layer to prevent the occurrence of stains on the screen.

Third, since the black matrix layer is formed of a metal material, vertical patterns are possible, thereby improving uniformity of the critical dimension (CD), thereby securing a bonding margin when the upper and lower substrates are bonded.

Fourth, since the black matrix layer may be formed of a metal material to form a fine pattern, the yield may be improved by forming a relatively stable pattern.

Fifth, the TN mode process line can be used as it is, so it is economical because unnecessary facility investment is unnecessary.

Claims (13)

A lower substrate having a pixel region defined therein, the lower substrate including a common electrode and a pixel electrode to drive the transverse electric field; A black matrix layer formed of a metallic material on an upper portion except the portion corresponding to the pixel region, a color filter layer formed on a portion corresponding to the pixel region, and an insulating film on the entire surface including the black matrix layer and the color filter layer; An upper substrate bonded to the lower substrate and having a predetermined space; A transverse electric field liquid crystal display device comprising a liquid crystal layer injected between the upper and lower substrates. The method of claim 1, And the black matrix layer is formed of a metallic material of Fe, Fe + FeOx, Cr, Cr + CrOx, or CrOx + Cr + CrOx. The method of claim 1, And the insulating film is formed of an organic film or an inorganic film having a dielectric constant &lt; 3, transmittance &gt; 95%, flatness &gt; 90%, and hardness &gt; 3H. The method of claim 1, And the insulating film is formed to have a thickness of approximately 2 μm or more. The method of claim 3, wherein And the insulating film Al2O3, O2, SiNx or SiO2 is formed of an inorganic film. The method of claim 1, A plurality of gate lines and data lines arranged on the lower substrate so as to cross each other to define the pixel area; The common electrode and the pixel electrode alternately formed in the pixel areas where the gate line and the data line cross each other; And a thin film transistor formed at a portion where the gate lines and the data lines cross each other. In the method of manufacturing a transverse electric field type liquid crystal display device composed of upper and lower substrates bonded to each other with a predetermined space having a defined pixel area, Forming a black matrix layer formed of a metal material on the upper substrate except for the pixel region; Forming a color filter layer on an upper substrate corresponding to the pixel region; And forming an insulating film on the entire surface of the upper substrate. The method of claim 7, wherein And forming a transparent conductive film on the rear surface of the upper substrate. The method of claim 7, wherein Depositing a metal material on the entire front surface of the black matrix layer; Applying a photoresist film on the metal material and selectively patterning the photoresist film so as to remain in only one region in an exposure and development process; Etching the metal material using the patterned photoresist as a mask; And removing the photosensitive film. The method of claim 7, wherein The metal material is Fe, Fe + FeOx, Cr, Cr + CrOx or CrOx + Cr + CrOx manufacturing method of a transverse electric field type liquid crystal display device characterized in that formed. The method of claim 7, wherein And said insulating film uses an inorganic film or an organic film having a dielectric constant &lt; 3, transmittance &gt; 95%, flatness &gt; 90%, and hardness &gt; 3H. The method of claim 7, wherein The insulating film is formed to have a thickness of 2㎛ or more method of the liquid crystal display device of the transverse electric field method. The method of claim 7, wherein The color filter layer may include forming R, G, and B color filter layers in each pixel region through a process of coating, exposing, and developing a color sensing material of R, G, and B on the upper substrate, respectively. A method of manufacturing a transverse electric field type liquid crystal display device.

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