KR20060079705A - Liquid crystal display apparatus, inner polarizer and manufacturing method thereof - Google Patents

Abstract

In the present invention, an alignment layer is formed on inner surfaces of the thin film transistor array panel and the color filter panel, and a thin crystal film (TCF) is coated thereon to form an internal polarizer.

By forming an internal polarizing plate having a double-layer structure of the alignment layer for the internal polarizing plate and the internal polarizing plate body, it is not necessary to separately prepare a polarizing plate and form it on the outside of the panel, thereby reducing the cost and the number of processes. Moreover, the orientation film for internal polarizing plates is formed, and the polarization characteristic which the liquid crystal in an internal polarizing plate main body has is improved.

Internal polarizer, alignment film, liquid crystal display device

Description

Liquid crystal display device, internal polarizer and its formation method {LIQUID CRYSTAL DISPLAY APPARATUS, INNER POLARIZER AND MANUFACTURING METHOD THEREOF}

1 is a cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.

2 is a flowchart illustrating a method of forming an internal polarizer according to an exemplary embodiment of the present invention.

3 is a flowchart illustrating a method of forming a main body of an internal polarizing plate.

<Explanation of symbols for the main parts of the drawings>

3: liquid crystal layer

11, 21: alignment film 12, 22: internal polarizing plate body

13, 23: alignment film for internal polarizing plate

100: thin film transistor array panel 110: lower insulating substrate

124: gate electrode 140: gate insulating film

154: semiconductor layer 163, 165: ohmic contact layer

173: source electrode 175: drain electrode

180: protective film 185: organic insulating film

190: pixel electrode 195: reflective electrode

200: color filter display plate 210: upper insulating substrate

220: black matrix 230: color filter

250: planarization film 270: common electrode

The present invention relates to a liquid crystal display device, an internal polarizer and a method of forming the same.

Liquid crystal displays (LCDs) are one of the most widely used flat panel display devices. The liquid crystal display (LCD) is composed of two substrates having electrodes and a liquid crystal layer interposed therebetween. The display device adjusts the transmittance of light passing through the liquid crystal layer by rearranging the liquid crystal molecules of the liquid crystal layer. In this case, the light transmittance is determined by phase retardation caused by the optical properties of the liquid crystal material when passing through the liquid crystal layer, and the phase retardation is controlled by adjusting the refractive index anisotropy of the liquid crystal material and the distance between the two substrates. Decide

Among the liquid crystal display devices, a liquid crystal display device having a thin film transistor (TFT) that has electrodes on each of two substrates and switches a voltage applied to the electrodes is one of the two liquid crystal display devices. It is generally formed in.

Such a liquid crystal display displays an image by transmitting light emitted by a backlight, which is a specific light source, to the liquid crystal layer to display an image, and external light such as natural light reflected by the reflective electrode of the liquid crystal display to the liquid crystal layer. It can be divided into a reflective type, and recently, a semi-transmissive mode that operates in both a reflection mode and a transmission mode has been developed.

On the other hand, a general liquid crystal display device is provided with a color filter of red, green, and blue to display a color image. The color image is obtained by adjusting the transmittance of light passing through each of the color filters of red, green, and blue.

Polarizers are formed on the upper and lower parts of the liquid crystal display. The upper and lower polarizers are formed parallel to each other or perpendicular to each other to display white or black light incident from the backlight. If the upper and lower polarizers are formed on the outside, the polarizers must be prepared separately, and a separate attachment process is required.

The technical problem to be achieved by the present invention is an invention for forming a polarizing plate is improved polarization performance without a separate attachment process.

In order to solve this problem, in the present invention, an alignment layer is formed on the inner surfaces of the thin film transistor array panel and the color filter panel, and an internal polarizing plate is formed by coating a thin crystal film (TPF) thereon.

Specifically, a thin film transistor array panel on which a thin film transistor and a pixel electrode are formed, an upper panel facing the thin film transistor array panel, on which a common electrode is formed, a liquid crystal formed between the thin film transistor array panel and the upper display panel, A first internal polarizer plate formed on the pixel electrode, a second internal polarizer plate formed under the common electrode, a first internal polarizer plate formed on the first internal polarizer plate, and a second inside It relates to a liquid crystal display device comprising a second internal polarizing plate body formed under the alignment film for polarizing plates,

It is preferable that the said oriented film for 1st and 2nd internal polarizing plates is formed with the polyimide,

Preferably, the first and second internal polarizer bodies are formed of a thin crystal film (TPF).

The liquid crystal alignment direction of the TCF of the first internal polarizing plate body and the direction in which the alignment film for the first internal polarizing plate aligns the liquid crystal of the TCF are the same, and the liquid crystal alignment direction of the TCF of the second internal polarizing plate body It is preferable that the direction in which the said oriented film for internal polarizing plates orientates the liquid crystal of said TCF is the same,

The present invention relates to an internal polarizing plate including an internal polarizing plate body formed of a material containing a liquid crystal, and an alignment layer formed under the internal polarizing plate body and capable of controlling the liquid crystal of the internal polarizing plate body.

It is preferable that the orientation direction of the liquid crystal which the said internal polarizing plate main body has and the direction in which the said orientation film orientates a liquid crystal,

Uniformly applying a polyimide to a region to form an inner polarizing plate, rubbing the surface of the polyimide, cleaning the surface of the rubbed polyimide, performing a plasma treatment on the cleaned surface, A method of forming an internal polarizer comprising coating a material having liquid crystallinity, patterning the coated material, and stabilizing the patterned material.

Preferably, the material having liquid crystallinity is TCF (thin crystal film),

Preferably, the coating is formed such that the direction in which the liquid crystal in the TCF is aligned and the direction in which the rubbed polyimide orients the liquid crystal are the same.

In the method for coating the liquid crystal material, it is preferable to use a FAS Slot die coating method or a Mayer rod coating method.

The step of patterning the coated material is preferably patterned using deionized water (Dionized water),

In the stabilizing of the patterned material, it is preferable to stabilize the TCF by using barium chloride (BaCl 2).

DETAILED DESCRIPTION Embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a part of a layer, film, area, plate, etc. is said to be "on" another part, this includes not only the other part being "right over" but also another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle.

A liquid crystal display, an internal polarizing plate, and a manufacturing method thereof according to an embodiment of the present invention will now be described in detail with reference to the drawings.

1 is a cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.

Although the transflective liquid crystal display device is illustrated in FIG. 1, the internal polarizer of the present invention may be formed in any liquid crystal display device such as a transflective type, a transmissive type, or a reflective type. Hereinafter, a description will be given of the transflective liquid crystal display.

The transflective liquid crystal display according to the exemplary embodiment of the present invention includes a thin film transistor array panel 100 and a color filter panel 200 facing each other and a liquid crystal layer 3 injected between the two display panels 100 and 200. do.

In the thin film transistor array panel 100 and the color filter panel 200, alignment layers 11 and 21 for controlling the liquid crystal layer are formed. Lower internal polarizers 12 and 13 are formed under the alignment layer 11 of the thin film transistor array panel 100, and upper internal polarizers 22 and 23 are formed on the alignment layer 21 of the color filter display panel 200. have. The upper and lower inner polarizing plates 12, 13, 22, and 23 are made up of the alignment films 13 and 23 for the inner polarizing plate and the inner polarizing plate bodies 12 and 22.

In the thin film transistor array panel 100, gate lines and data lines are formed to cross each other to define a unit pixel area of a matrix array. Each pixel area includes a thin film transistor TFT connected to a gate line and a data line, and a pixel electrode electrically connected to the thin film transistor TFT. The pixel electrode includes a transparent electrode 190 made of a transparent conductive film and a reflective electrode 195 formed of a conductive film having a reflectance. The surface of the reflective electrode 195 is generally embossed. Hereinafter, the region where the reflective electrode 195 is formed is referred to as the "reflection region R", and the region where only the transparent electrode 190 is formed is referred to as the "transmission region T".

In the color filter panel 200 facing the thin film transistor array panel 100, a black matrix 220 having an opening corresponding to the pixel region is formed, and the red, green, and blue color filters 230 are formed in each pixel region. Each of the color filters 230 of red, green, and blue may be formed to have different thicknesses according to the display areas R and T. In the present embodiment, an embodiment having the same thickness is illustrated. . The color filter 230 is covered with a planarization film 250 made of an organic insulating material, and a common electrode 270 is formed on the planarization film 250.

The reflective region R is used to display an image using light reflected from the reflective electrode 195, and the transparent region T is used to display an image using light from a backlight, that is, its own light source.

Next, the structure of the thin film transistor array panel in the transflective liquid crystal display according to the exemplary embodiment of the present invention will be described in more detail.

The thin film transistor array panel 100 includes an insulating substrate 110. A plurality of gate lines extending mainly in the horizontal direction are formed on the insulating substrate 110. The gate line may comprise a single layer of low resistivity material, for example silver or silver alloy or aluminum or aluminum alloy. Alternatively, the gate line may be formed of a multilayer film including at least one film containing the above-described material and at least one film for pads having excellent contact properties with other materials. An example of the multilayer film is a double layer of aluminum and molybdenum alloy. The portion located near one end of the gate line transmits a gate signal from the outside to the gate line, and a plurality of branches of each gate line form the gate electrode 124 of the thin film transistor.

A gate insulating layer 140 made of silicon nitride (SiNx) covers the gate line.

An island-like semiconductor 154 made of hydrogenated amorphous silicon or the like is formed on the gate insulating layer 140 on the gate electrode 124, and n + hydrogenation in which silicide or n-type impurities are heavily doped is formed on the semiconductor 154. A plurality of pairs of ohmic contacts 163 and 165 made of amorphous silicon are formed. Each pair of ohmic contacts 163 and 165 are separated from each other with respect to the corresponding gate line.

A plurality of data lines and a plurality of drain electrodes 175 are formed on the ohmic contacts 163 and 165 and the gate insulating layer 140. The data line and the drain electrode 175 include a conductive film made of a low resistance conductive material such as aluminum or silver. The data line mainly extends in the vertical direction and crosses the gate line. The plurality of branches 173 of the data line extends to an upper portion of one of the pair of ohmic contacts 163 and 165 to form the source electrode 173 of the thin film transistor. One end of the data line is enlarged in order to transfer an image signal from the outside to the data line. The drain electrode 175 of the thin film transistor is separated from the data line and positioned above the ohmic contact layer 165 opposite to the source electrode 173 with respect to the gate electrode 124.

A passivation layer 180 formed of silicon nitride or the like and an organic insulating layer 185 made of an organic material having excellent planarization characteristics are formed on the data line and drain electrode 175 and the semiconductor 154 that does not cover the semiconductor line 154.

In the passivation layer 180 and the organic insulating layer 185, contact holes exposing the drain electrode 175 are formed. The transparent electrode 190 is electrically connected to the drain electrode 175 through the contact hole 185. Here, the transparent electrode 190 is made of indium tin oxide (ITO) or indium zinc oxide (IZO), which are transparent conductive materials.

The reflective electrode 195 is formed in a portion of the upper portion of the transparent electrode 190. The reflective electrode 195 is made of a conductive film having a high reflectance such as aluminum or an aluminum alloy, silver or silver alloy, molybdenum or molybdenum alloy. Unevenness may be formed on the surface of the reflective electrode 195. The reflective electrode 195 and the transparent electrode 190 are paired to form a pixel electrode.

On the pixel electrode, the alignment film 13 for internal polarizing plates is formed. The internal polarizing plate main body 12 is formed on the internal alignment film 13 for internal polarizing plates. Here, the alignment layer 13 for the internal polarizing plate is made of polyimide, and the internal polarizing plate body 12 is made of a thin crystal film (TCF) or the like, and a method of forming the lower internal polarizing plates 12 and 13 is described. It will be described later.

An alignment layer 11 is formed on the lower internal polarizers 12 and 13.

Meanwhile, a black matrix 220 is formed on the color filter display panel 200 facing the thin film transistor array panel 100 to prevent light leakage from the pixel edge on the upper insulating substrate 210. The black matrix 220 formed on the color filter display panel 200 is formed not only at each pixel edge but also at an edge of the display area including a plurality of pixels.

Red, green, and blue color filters 230 are formed in regions where the black matrix 220 is not formed. The planarization layer 250 is formed on the sal filter 230 and the black matrix 220, and a common electrode 270 is formed on the sal filter 230 and the black matrix 220. The common electrode 270 is formed of a transparent conductor such as ITO or IZO.

An internal polarizer alignment layer 23 is formed on the common electrode 270, and an internal polarizer main body 22 is formed thereon. The alignment layer 21 is formed on the upper internal polarizers 22 and 23. Here, the alignment layer 23 for the internal polarizing plate is made of polyimide (PI), and the internal polarizing plate body 22 is made of a thin crystal film (TCF) or the like. The upper inner polarizers 22 and 23 are formed by the same forming method as the lower inner polarizers 12 and 13, and will be described below with reference to the lower polarizers 12 and 13. The method of forming an internal polarizing plate is as follows.

2 is a flowchart illustrating a method of forming an internal polarizer according to an exemplary embodiment of the present invention, and FIG. 3 is a flowchart illustrating a method of forming a main body of the internal polarizer.

As shown in FIG. 1, the internal polarizer includes an internal polarizer alignment layer 13 and an internal polarizer main body 12 formed thereon. Therefore, the alignment film 13 for the inner polarizer must be formed first. To this end, polyimide (PI) is uniformly applied (S1), and then the surface of the polyimide (PI) is rubbed (S2). The direction in which the liquid crystal is aligned above the alignment layer 13 through rubbing is referred to as a first direction below. By rubbing the polyimide (PI), the alignment film 13 for the internal polarizing plate is completed, and the internal polarizing plate main body 12 is formed thereon (S3).

The method of forming the internal polarizer body 12 in accordance with an embodiment of the present invention is described in detail in FIG.

First, in order to form the internal polarizing plate body 12, the portion where the internal polarizing plate body 12 is to be formed is cleaned (S3-1). That is, the surface of the internal polarizing plate oriented film 13 is washed and processed cleanly. Thereafter, plasma processing is performed on the cleaned surface of the alignment film 13 for the internal polarizing plate (S3-2). Due to the plasma treatment, the characteristics of the internal polarizing plate body 12 formed later are improved.

Thereafter, the internal polarizing plate main body 12 is coated with a material (S3-3). A material used as the inner polarizing plate body 12 is generally used as a thin crystal film (TCF), hereinafter referred to as TCF on behalf of the material forming the inner polarizing plate body 12. As a method of coating the internal polarizers 12 and 22, a FAS slot die coating method and a mayr rod coating method are generally used. TCF, which is a material used for the internal polarizing plate body 12, is also a dichroic dye having liquid crystallinity (including a liquid crystal). Therefore, when coating the TCF to give a direction by coating in a constant direction. This coating direction generally becomes the transmission axis direction of an internal polarizing plate.

In this embodiment, the alignment layer 13 for the internal polarizing plate 13 is formed so as to coincide with the direction in which the liquid crystal is aligned through the rubbing (first direction) and the direction in which the liquid crystal is aligned by coating the TCF.

Thereafter, the coated TCF is patterned using DI water (Deionized water) from which ions are removed (S3-4). TCF is soluble in water, so pattern it using DI water. The material to be patterned also changes depending on the material forming the internal polarizers 12 and 22.

Thereafter, barium chloride (BaCl 2) is used to stabilize the patterned TCF (S3-5). This provides barium chloride to the TCF to prevent it from being etched by water.

Through this process, the internal polarizer main body 12 is formed, and the internal polarizer main body 12 itself serves as a polarizing plate, but in order to improve the polarization characteristics of the internal polarizer main body 12, an internal alignment film for internal polarizer ( 13) to help the alignment of the liquid crystals well in the first direction.

In the present exemplary embodiment, the lower inner polarizers 12 and 13 and the upper inner polarizers 22 and 23 are disposed under the alignment layers 11 and 21, respectively, but the layered structure may be different. For example, the upper internal polarizers 22 and 23 may be formed below the planarization layer 250 in the color filter panel 200.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

As described above, by forming the internal polarizing plate having a two-layer structure of the alignment layer for the internal polarizing plate and the internal polarizing plate main body, there is no need to prepare a polarizing plate separately and form the outside of the panel, thereby reducing the cost and the number of processes. Moreover, the orientation film for internal polarizing plates is formed, and the polarization characteristic which the liquid crystal in an internal polarizing plate main body has is improved.

Claims (12)

A thin film transistor array panel on which a thin film transistor and a pixel electrode are formed, An upper panel facing the thin film transistor array panel and having a common electrode formed thereon; A liquid crystal formed between the thin film transistor array panel and the upper panel; An alignment film for a first internal polarizing plate formed on the pixel electrode, An alignment film for a second internal polarizing plate formed under the common electrode; A first inner polarizing plate body formed on the alignment layer for the first inner polarizing plate, And a second internal polarizer main body formed under the second internal polarizer alignment film. In claim 1, And the alignment layers for the first and second internal polarizing plates are formed of polyimide. In claim 1, The first and second internal polarizer bodies are formed of a thin crystal film (TPF). In claim 3, The liquid crystal alignment direction of the TCF of the first internal polarizing plate body and the direction in which the alignment film for the first internal polarizing plate orients the liquid crystal of the TCF are the same, The liquid crystal display device of the said TCF which the said 2nd internal polarizing plate main body has, and the direction in which the alignment film for 2nd internal polarizing plates orientate the liquid crystal of said TCF are the same. An internal polarizing plate body formed of a material containing a liquid crystal, An inner polarizing plate formed under the inner polarizing plate body and including an alignment layer capable of controlling liquid crystal of the inner polarizing plate body. In claim 5, The internal polarizing plate of the same orientation direction of the liquid crystal which the said internal polarizing plate body has, and the direction in which the said alignment film orientates a liquid crystal. Uniformly applying a polyimide to a region where an internal polarizer is to be formed, Rubbing the surface of the polyimide, Cleaning the surface of the rubbed polyimide, Performing a plasma treatment on the cleaned surface; Coating the material having the liquid crystallinity, Patterning the coated material, Stabilizing the patterned material. In claim 7, And the liquid crystal material is a thin crystal film (TPF). In claim 8, And a direction in which the direction in which the liquid crystal in the TCF is aligned and the direction in which the rubbed polyimide orients the liquid crystal through the coating are the same. In claim 7, The method of coating the liquid crystal material is a method of forming an internal polarizing plate using a FAS Slot die coating method or a Mayer rod coating method. In claim 7, The patterning of the coated material is a method of forming an internal polarizer using patterned deionized water using DI water (Deionized water). In claim 7, The stabilizing of the patterned material is a method of forming an internal polarizer to stabilize the TCF using barium chloride (BaCl₂).

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