KR20060082095A - Manufacturing method of inner polarizer - Google Patents

Abstract

In the present invention, an internal polarizing plate is formed by coating a thin crystal film (TCF) on the inner surfaces of the thin film transistor array panel and the color filter panel and baking at a low temperature compared to the baking temperature of a subsequent process.

By forming in this way, there is no need for a polarizing plate separately, and there is no need for an attaching step for attaching the polarizing plate. In addition, by baking at a temperature lower than the baking temperature of the subsequent process to remove moisture of the internal alignment layer, cracks do not occur even if the baking temperature of the subsequent process is high, thereby improving the performance of the internal polarizing plate.

Internal Polarizer, TCF, Low Temperature Bake

Description

MANUFACTURING METHOD OF INNER POLARIZER

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 a first embodiment of the present invention.

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

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

FIG. 5 is a view illustrating a crack formed on an inner polarizer. FIG.

6 to 9 illustrate the internal polarizer in the case where the internal polarizer is formed according to the first exemplary embodiment of the present invention and in subsequent processes.

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

3: liquid crystal layer

11, 21: alignment film 12, 22: 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

This invention is the invention regarding the formation method of an internal polarizing plate.

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 upper and lower sides 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. When the upper and lower polarizers are formed on the outside, a separate polarizer must be prepared, and a separate attachment process is required.

The technical problem to be achieved by the present invention is an invention for providing a method for forming the upper and lower polarizing plate without a separate attachment process.

In order to solve this problem, in the present invention, an internal polarizer is formed by coating a thin crystal film (TCF) on the inner surfaces of the thin film transistor array panel and the color filter panel and baking at a low temperature compared to the bake temperature of a subsequent process. do.

Specifically, cleaning the portion where the internal polarizer is to be formed, performing a plasma treatment on the cleaned portion, coating a material of the internal polarizer, patterning the coated material, and patterning the patterned material It relates to a method of forming an internal polarizing plate comprising the step of stabilizing, low-temperature baking the stabilized material to a temperature lower than the baking temperature in a subsequent process,

The material of the internal polarizer is preferably a thin crystal film (TCF),

In the method of coating the material of the internal polarizing plate, it is preferable to use FAS Slot die coating method or Mayer rod coating method.

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

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

The low temperature baking may be a temperature of 60 degrees or more and 130 degrees or less, and a baking time of 3 minutes or more and 120 minutes or less,

Cleaning a portion where an internal polarizer is to be formed, performing a plasma treatment on the cleaned portion, coating a material of the internal polarizer, and baking the coated material at a temperature lower than a baking temperature in a subsequent process. It relates to a method of forming an internal polarizing plate comprising the step of: patterning the cold baked material, stabilizing the patterned material,

Cleaning the portion where the internal polarizer is to be formed, subjecting the cleaned portion to plasma treatment, coating the material of the internal polarizer, patterning the coated material, and subjecting the patterned material to subsequent processing. It relates to a method of forming an internal polarizing plate comprising the step of low temperature baking at a temperature lower than the baking temperature, and stabilizing the low temperature baked material.

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, region, 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.

Now, a method of forming an internal polarizing plate according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying 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. The lower internal polarizer 12 is formed under the alignment layer 11 of the thin film transistor array panel 100, and the upper internal polarizer 22 is formed on the alignment layer 21 of the color filter display panel 200.

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 shown. . 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 electrode 124.

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. At one end of the data line, an enlarged portion is formed 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.

A contact hole for exposing the drain electrode 175 is formed in the passivation layer 180 and the organic insulating layer 185, respectively. 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.

The internal polarizer 12 is formed on the pixel electrode. The internal polarizing plate 12 is made of a thin crystal film (TPF) or the like, and a method of forming the internal polarizing plate 12 will be described later.

The alignment film 11 is formed on the internal polarizing plate 12.

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 22 is formed on the common electrode 270, and an alignment layer 21 is formed thereon. Here, the internal polarizer 22 is made of a thin crystal film (TPF) or the like.

Hereinafter, a method of forming the internal polarizers 12 and 22 will be described as illustrated in FIGS. 2 to 4.

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

According to the exemplary embodiment of the present invention, the lower inner polarizer 12 is formed on the pixel electrode of the thin film transistor array panel 100, and the upper inner polarizer 22 is formed on the common electrode 270 of the color filter panel 200. do.

Therefore, the method of forming the internal polarizer illustrated in FIG. 2 is a process proceeding after the pixel electrode of the thin film transistor array panel 100 is formed in the case of the lower internal polarizer 12, and the upper internal polarizer 22 of the upper part is formed. ), The process proceeds after the common electrode 270 of the color filter panel 200 is formed. This is also the case in FIGS. 3 and 4.

First, in order to form the internal polarizers 12 and 22, the portions on which the internal polarizers 12 and 22 are to be formed are cleaned (S1). That is, in the case of the lower internal polarizer 12, the surface of the pixel electrode is cleaned, and in the case of the upper internal polarizer 22, the surface of the common electrode is cleaned. Thereafter, the washed portion is subjected to plasma treatment (S2). By performing the plasma treatment, the characteristics of the internal polarizing plates 12 and 22 formed later are improved.

Thereafter, the internal polarizers 12 and 22 are coated with a material for forming (S3). As a material used for the internal polarizers 12 and 22, a thin crystal film (TCF) is generally used, and methods of coating the internal polarizers 12 and 22 generally include a FAS slot die coating method and a FAS slot die coating method. Mayer rod coating etc. are used. The polarizing direction is determined according to the coating direction of the internal polarizing plate. In the case of TCF, the coating direction is the direction of the transmission axis. That is, light in the coating direction is transmitted, and light perpendicular thereto is blocked.

Then, the material (hereinafter referred to as TCF) of the inner polarizing plates 12 and 22 coated using DI water (Deionized water) from which ions are removed is patterned (S4). 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, the patterned TCF is stabilized using barium chloride (BaCl 2) or the like (S5). This provides barium chloride to the TCF to prevent it from being etched by water.

Thereafter, the stabilized TCF is baked at low temperature to complete the internal polarizing plates 12 and 22 (S6). Here, the low temperature is lower than the temperature of the bake process that occurs in the subsequent process from the formation of the internal polarizers 12 and 22 to the completion of the display panels 100 and 200. In general, the temperature of the low temperature baking process is about 60 to 130 degrees, and the baking time is about 3 to 120 minutes.                     

Thereafter, a subsequent step (in this embodiment, an alignment film forming step) is performed.

The low temperature bake process is performed because the internal polarizers 12 and 22 often contain moisture, so that cracks are generated in the internal polarizers 12 and 22 during the high temperature bake of the subsequent process. The low temperature bake treatment S6 is a step for removing moisture in the internal polarizing plates 12 and 22.

3 is a flowchart illustrating a method of forming an internal polarizer according to a second exemplary embodiment of the present invention, and FIG. 4 is a flowchart illustrating a method of forming an internal polarizer according to a third exemplary embodiment of the present invention.

The method of forming the internal polarizers 12 and 22 shown in FIGS. 3 and 4 is different from that of FIG. 2.

Referring to FIG. 3, after cleaning the portions in which the internal polarizers 12 and 22 are to be formed (S10) and performing a plasma treatment on the cleaned portions (S20), the material of the internal polarizers 12 and 22 (typically TCF) To coat (S30). Thereafter, baking is performed at a temperature lower than the baking temperature of a subsequent process (S40), and the internal polarizing plates 12 and 22 are patterned using DI water (Sion). Here, it is preferable not to contact the DI water except for a portion which is patterned and removed in the step of patterning using DI water. Thereafter, barium chloride (BaCl 2) or the like is used to stabilize the patterned internal polarizing plates 12 and 22 (S60).

On the other hand, Figure 4 is to clean the portion in which the internal polarizing plate (12, 22) is to be formed (S100), after the plasma treatment of the cleaned portion (S200), the material of the internal polarizing plate (12, 22) (typically TCF) To coat (S300). Thereafter, the internal polarizers 12 and 22 are patterned using DI water (Sion) and baked at a temperature lower than the baking temperature of a subsequent process (S500). Thereafter, the patterned internal polarizers 12 and 22 are stabilized using barium chloride (BaCl 2) (S600).

Internal polarizers 12 and 22 may be formed through the method as illustrated in FIGS. 2 to 4. Among these methods, the internal polarizers 12 and 22 formed by the method illustrated in FIG. 2 will be described below.

5 is a view showing a crack formed on the inner polarizing plate, and FIGS. 6 to 9 are views of the inner polarizing plate when the inner polarizing plate is formed according to the first embodiment of the present invention and in subsequent steps. This picture shows how it looks.

First, FIG. 5 illustrates a case in which cracks are formed in the internal polarizing plate so that performance of the internal polarizing plate is difficult to be exhibited. As shown in FIG. 5, cracking occurred when the subsequent process was performed without performing the low temperature bake treatment step S6 in the forming method shown in FIG. 2. This crack is generated as the moisture contained in the internal polarizing plate evaporates the moisture to the outside in the high temperature baking process of the subsequent process, in order to eliminate this disadvantage, in the present invention, a low temperature baking process (S6) was added.

FIG. 6 is a view illustrating an internal polarizer after performing steps S1 to S5 of FIG. 2 (before the low temperature bake process S6). As can be seen in Figure 6 it can be seen that no crack has occurred.

FIG. 7 is a view illustrating an internal polarizer after performing step S6 (low temperature bake step; bake for 3 minutes at 100 degrees) of FIG. 2. As in FIG. 6, it can be seen that no crack is generated in FIG. 7.

8 is a view illustrating an internal polarizer after baking in a subsequent process. The bake here was baked at 135 degrees for 3 minutes. As illustrated in FIG. 8, no crack was generated in the internal polarizer.

9 was baked by raising the temperature of the baking of the subsequent process. That is, after baking at 200 degrees for 3 minutes, the internal polarizer is shown. In FIG. 9, no crack was generated in the internal polarizer.

As described above, by removing the moisture contained in the internal polarizing plate in advance through a low temperature bake process, cracking does not occur even when baking at a high temperature in a subsequent process.

In the present exemplary embodiment, the internal polarizers 12 and 22 are disposed under the alignment layers 11 and 21, but the color filter display panel 200 may be formed below the planarization layer 250. That is, the position at which the internal polarizers 12 and 22 are formed may be formed differently from the layered structure of the present embodiment. Even if the positions for forming the internal polarizing plates 12 and 22 are different, the forming method shown in FIGS. 2 to 4 is equally applied.

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.

 By forming the internal alignment layer by the method as described above, the polarizer is not required separately, and also the attachment process for attaching the same does not require the cost, thereby reducing the cost. In addition, by baking at a temperature lower than the baking temperature of the subsequent process to remove moisture of the internal alignment layer, cracks do not occur even if the baking temperature of the subsequent process is high, thereby improving the performance of the internal polarizing plate.

Claims (8)

Cleaning the portion where the internal polarizer is to be formed, Performing a plasma treatment on the cleaned portion, Coating a material of the internal polarizer; Patterning the coated material, Stabilizing the patterned material, Baking the stabilized material at a temperature lower than the baking temperature in a subsequent process. In claim 1, And a material of the internal polarizer is a thin crystal film (TPF). In claim 1, The method of coating the material of the internal polarizing plate is a method of forming an internal polarizing plate using a FAS Slot die coating method or Mayr rod coating method. In claim 1, 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 2, The stabilizing of the patterned material is a method of forming an internal polarizer to stabilize the TCF using barium chloride (BaCl₂). In claim 1, The low temperature baking may include a temperature of 60 degrees or more and 130 degrees or less, and a baking time of 3 minutes or more and 120 minutes or less. Cleaning the portion where the internal polarizer is to be formed, Performing a plasma treatment on the cleaned portion, Coating a material of the internal polarizer; Low temperature baking the coated material to a temperature lower than the baking temperature in a subsequent process, Patterning the cold baked material, Stabilizing the patterned material. Cleaning the portion where the internal polarizer is to be formed, Performing a plasma treatment on the cleaned portion, Coating a material of the internal polarizer; Patterning the coated material, Low temperature baking the patterned material to a temperature lower than the baking temperature in a subsequent process, Stabilizing the low temperature baked material.

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