KR20070097733A - Method for manufacturing liquid crystal display device - Google Patents

Abstract

A method for manufacturing an LCD(Liquid Crystal Display) is provided to prevent generation of defect previously by performing a bad coating check during a process and to improve productivity by performing re-process. A method for manufacturing an LCD(Liquid Crystal Display) includes the steps of: coating a material layer on a substrate(11S); calculating a local thickness difference by measuring a thickness of the coated material layer(13S); removing the coated material layer and performing a re-coating process if the calculated local thickness difference is bigger than a reference value(14S,15S); and proceeding the next process if the calculated local thickness difference is smaller than the reference value(18S).

Description

Method for manufacturing liquid crystal display device

1 is a flow chart of a liquid crystal display device of a conventional liquid crystal dropping method

2 is a plan view illustrating a process of coating a photosensitive film using a nozzle apparatus to form a column spacer according to the present invention.

3 is a process flowchart of the liquid crystal display according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display device, and in particular, to manufacture a liquid crystal display device by coating a material layer for forming a column spacer and measuring a thickness of the coated material layer so as to perform a reprocessing process in case of coating failure. It is about a method.

As the information society develops, the demand for display devices is increasing in various forms, and in recent years, the LCD (Lipuid Crystal Display Device), PDP (Plasma Display Panel), ELD (Electro Luminescent Display), and VFD (Vacuum Fluorescent) Various flat panel display devices such as displays have been studied, and some of them are already used as display devices in various devices.

Among them, LCD is the most widely used, replacing the CRT (Cathode Ray Tube) for mobile image display because of its excellent image quality, light weight, thinness, and low power consumption. 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 is often arranged with the above advantages. Therefore, in order to use a liquid crystal display device in various parts as a general screen display device, the key to development is how much high definition images such as high definition, high brightness, and large area can be realized while maintaining the characteristics of light weight, thinness, and low power consumption. It can be said.

Such a liquid crystal display may be largely 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 has a predetermined space and is bonded to the first and second glass substrates. And a liquid crystal layer injected between the first and second glass substrates.

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 Transistors are 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 and B color filter layer for expressing color colors, and a common electrode for implementing an image. Is formed.

The first and second substrates are bonded to each other by a seal material having a predetermined space by a spacer and having a liquid crystal injection hole, so that the liquid crystal is injected between the two substrates.

At this time, 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 liquid by maintaining the vacuum state between the two substrates bonded by the real material. When the liquid crystal is injected as described above, the liquid crystal injection hole is sealed with a sealing material.

However, the liquid crystal display device manufacturing method according to the conventional liquid crystal injection method takes a long time to inject the liquid crystal, so the productivity is lowered, especially when manufacturing a large-area liquid crystal display device for about 30 hours or more If the liquid crystal is not injected completely, defects may occur.

Therefore, in recent years, a method of manufacturing a liquid crystal display device of a liquid crystal dropping method in which an appropriate amount of liquid crystal is dropped on one of two substrates and then bonded to two substrates before bonding two substrates together.

As described above, in order to manufacture a liquid crystal display using a liquid crystal dropping method, a column spacer in which a spacer for securing a space between two substrates is fixed to the substrate should be formed on one of the two substrates.

A conventional method for manufacturing a liquid crystal display device of a liquid crystal dropping method is as follows.

1 is a process flowchart of a liquid crystal display device according to a conventional liquid crystal dropping method.

A plurality of panels are designed on the first glass disc to form a thin film transistor array having the above-described gate and data wirings, thin film transistors and pixel electrodes in each panel region (1S), and the plurality of panels on the second glass disc. Is designed to form a color filter array including the black matrix layer, the color filter layer, the common electrode and the like as described above in each panel region (2S).

In this case, a column spacer (Colunm spacer) is formed in each panel region of the second glass original plate to secure a constant space between the two substrates, and the first glass original plate and / or the color in which the thin film transistor array is formed. An alignment film is formed on each of the second glass original plates on which the filter array is formed, so that rubbing or photo alignment is performed.

The first and second glass original plates configured as described above are respectively washed (3S and 4S).

The washed at least one first and second glass discs are loaded into a liquid crystal dispenser (LC Dispenser) to drop an appropriate amount of liquid crystal onto each panel area, or loaded into an Ag dispenser and a sealant dispenser to each panel area. Ag dots are formed on the common voltage supply line of P, and seal materials for bonding the two substrates to the periphery of each panel region are applied (5S and 6S). That is, in the IPS mode liquid crystal display, since the common electrode is formed on the thin film transistor array substrate, it is not necessary to form Ag dots, but in the liquid crystal display device such as TN mode in which the common electrode is formed on the color filter array substrate, Ag dots are formed. shall. At this time, the sealing material uses a light and thermosetting resin and does not need to make a liquid crystal injection hole.

Here, although the liquid crystal was dropped on the first glass disc and the sealing material and Ag were coated on the second glass disc, the real and Ag dots were applied to the first glass disc on which the thin film transistor array was formed. The liquid crystal may be dropped into the second glass original plate on which the filter array is formed.

The first and second glass original plates are loaded into a vacuum bonding machine, and the first and second glass original plates are aligned and bonded so that the dropped liquid crystal is uniformly filled in each panel region (7S).

And the sealing material of the bonded 1st and 2nd glass disc is hardened (8S).

When the hardening of the sealing material is completed, the bonded first and second glass original plates are cut for each panel (9S).

Finally, the edge portion of each cut panel is polished (10S), and each panel is inspected for quality such as stains and streaks by an auto probe process to complete the liquid crystal display panel (11S).

However, such a conventional method for manufacturing a liquid crystal display device has the following problems.

In other words, it is impossible to recover the defective panel because the panel is cut by each panel and finally inspected for quality and judges whether the product is good or not good. Done.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a manufacturing method of a liquid crystal display device which can improve productivity by performing coating defect inspection during a process to prevent defects in advance and to perform reprocessing. The purpose is to provide.

According to an aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, including: coating a material layer on a substrate; Calculating a thickness of the coated material layer to produce a local thickness difference; If the calculated local thickness difference is greater than or equal to a reference value, removing all the coated material layers and performing a recoating process; And if the calculated local thickness difference is less than the reference value is characterized in that it comprises the step of proceeding to the next process.

In this case, the material layer is characterized in that the color filter layer for the liquid crystal display device, the overcoat layer production or column spacer production.

Hereinafter, a method of manufacturing a liquid crystal display device according to the present invention having the above characteristics will be described in detail with reference to the accompanying drawings.

First, as a result of analyzing the cause of streaks in the completed liquid crystal display panel, it was found that the biggest cause is the local height difference of the column spacer. In other words, it was found that the stripe defect occurs when the local height difference of the column spacer is more than a predetermined value.

The column spacer is deposited on the thin film transistor array substrate or the color filter array substrate, and the photoresist is patterned by an exposure and development process to form a region corresponding to a portion where the black matrix layer is formed.

By the way, as the liquid crystal panel size and the glass original plate are enlarged in recent years, the photosensitive film coating process for forming a column spacer is performed by the spray method using a nozzle.

That is, when the size of the liquid crystal panel and the glass plate is small, the photoresist film is coated by the spin coating method, so that the thickness of the photoresist film can be uniformly formed. The photosensitive film is coated by spraying using a nozzle.

Therefore, since the thickness of the photoresist film is not uniformly coated, the height difference of the column spacers is locally generated when the photoresist is patterned to form a column spacer by an exposure and development process.

2 is an explanatory diagram analyzing the cause when stripes are generated in the horizontal and vertical directions due to the height difference of the column spacer according to the present invention.

FIG. 2 illustrates a process of coating a photosensitive film on a large glass substrate by using a nozzle apparatus 1 having a plurality of nozzles in a scanning manner to form a column spacer or by moving the substrate 2. It shows the case where streaks are generated in the longitudinal direction (the direction of travel of the nozzle) 4 and the case where the streaks are generated in the horizontal direction (the direction perpendicular to the direction of travel of the nozzle) 3.

When streaks are generated in the longitudinal direction (the direction in which the nozzle proceeds) 4, the most likely occurrence occurs when a difference occurs in the injection amount of each nozzle constituting the nozzle device 1 during coating of the photosensitive film. I figured out.

In addition, when the stripe defect occurs in the horizontal direction (direction perpendicular to the traveling direction of the nozzle) 4, the probability that occurs when the scanning speed of the nozzle device 1 is not constant at the time of coating the photosensitive film It was large. That is, when the scanning speed of the nozzle device 1 is relatively fast, the photosensitive film is thinly coated. When the scanning speed of the nozzle device 1 is relatively slow, the photosensitive film is thickly coated.

Therefore, in the present invention, the photoresist is coated to form a column spacer, and before the exposure and development processes, the thickness of the coated photoresist is measured to determine whether the thickness difference is within a predetermined range, and to proceed with the subsequent process.

3 is a flowchart illustrating a column spacer of a liquid crystal display according to an exemplary embodiment of the present invention.

First, a photosensitive film is coated on a substrate to form a column spacer (11S).

Here, the substrate is one of a thin film transistor array substrate or a color filter array substrate.

That is, in the case of the thin film transistor array substrate, a plurality of gate lines and data lines formed in directions perpendicular to each other to define a pixel region, and a plurality of thin film transistors formed at intersections of the gate lines and the data lines; And a plurality of pixel electrodes formed in the pixel areas.

 In addition, in the case of a color filter array substrate, a black matrix layer formed to block light in portions other than the pixel areas, the R, G, and B color filter layers formed in the pixel areas, the black matrix layer and the color A common electrode or overcoat layer formed on the front surface of the substrate including the filter layer is provided.

Then, the thickness of the coated photoresist film is measured (12S), and the local thickness difference of the photoresist film is calculated (13S).

There may be various methods for measuring the thickness of the coated photoresist film. For example, a plurality of cameras may be provided to select a measurement area according to the resolution of each camera to arrange cameras in a row, and the plurality of cameras. It is provided with a driving means to move the X axis and the Y axis in a scan method, or to move the stage on which the substrate to be measured is located on the X axis and the Y axis.

Then, the image data photographed by the plurality of cameras is converted into an electrical signal, and the thickness of the coated photoresist film is measured with a main computer for implementing a 3D stereoscopic image. Then, the thickness difference is calculated locally by comparing the measured thicknesses.

The local thickness difference calculated by this method is compared with the reference value (14S). As a result of the comparison, if the calculated thickness difference is greater than the reference value K, the process proceeds to the reprocessing step 15S to remove all the coated photoresist (16S), and then proceeds to the photoresist coating process 11S.

At this time, the nozzle of the photosensitive film coating apparatus is inspected based on the calculated thickness difference, or the photosensitive film coating apparatus is adjusted so that the thickness difference does not occur by adjusting the arrangement of the nozzle and the coating speed.

As a result of the comparison in the step 14S, if the calculated thickness difference is less than the reference value, a mask is placed on the coated photoresist film to expose the column spacers, and the exposed photoresist is developed to form a color spacer pattern (17S). ).

After the column spacer pattern is formed, the next process is performed, such as depositing an alignment layer (18S).

Thereafter, although not shown in the drawings, the thin film transistor array substrate or the color filter array substrate on which the column spacer pattern is formed is washed, and a liquid crystal dropping process, a sealing material applying process, a process of bonding the two substrates, and the bonding The process of hardening the sealing material of the obtained board | substrate, the process of cutting the said bonded board | substrate for each unit panel, the process of grinding | polishing and quality inspection of each panel, etc. are performed.

In the above, when the thickness of the photoresist film deposited before the column spacer pattern is formed and the local thickness difference is greater than or equal to the reference value, the reprocessing is described. However, the present invention is not limited thereto, and the color filter layer forming process or the overcoat layer forming process is not limited thereto. Applicable to

That is, if a thickness difference is locally generated during the color filter layer formation, a defect occurs in color reproducibility, and if a thickness difference is locally generated during the overcoat layer formation, the height of the column spacer pattern is high even if the height of the column spacer pattern is uniform. Stripes can occur as if a difference occurred.

Therefore, after coating the color filter layer or the overcoat layer, as described in FIG. 3, the thickness of the color filter layer or the overcoat layer is measured to calculate a local thickness difference, and if the calculated thickness difference is greater than the reference value, the reprocessing step Proceed to remove all of the coated color filter layer or overcoat layer and proceed to the color filter layer or overcoat layer coating process again.

Of course, in this case as well, the conditions of the color filter layer or the overcoat layer coating apparatus are adjusted based on the calculated local thickness difference.

The manufacturing method of the liquid crystal display device according to the present invention as described above has the following effects.

First, the material for the color filter layer, the overcoat layer or the column spacer is coated, and the thickness of the coated material layer is measured to calculate the local thickness difference. If the calculated local thickness difference is equal to or greater than the reference value, the process is repeated. Since defects such as streaks and color reproducibility can be prevented in advance, productivity can be improved.

Second, before the liquid crystal panel of the liquid crystal display device is completed, re-working is performed according to a local thickness difference in each unit process, thereby improving defect recovery rate and lowering manufacturing cost.

Claims (4)

Coating a layer of material on the substrate; Calculating a thickness of the coated material layer to produce a local thickness difference; Removing the coated material layer and performing a recoating process if the calculated local thickness difference is equal to or greater than a reference value; And And if the calculated local thickness difference is less than or equal to the reference value, proceeding to the next step. The method of claim 1, The material layer is a manufacturing method of a liquid crystal display device, characterized in that for producing a color filter layer of the liquid crystal display device, for the overcoat layer production or column spacer production. The method of claim 1, The calculating of the local thickness difference by measuring the thickness of the coated material layer may include measuring the thickness of the material layer using a plurality of cameras, and converting the measured thickness into a 3D stereoscopic image to locally convert the thickness difference. The manufacturing method of the liquid crystal display device characterized by the above-mentioned. Coating a photosensitive film on the substrate; Calculating a thickness of the coated photoresist to calculate a local thickness difference; If the calculated local thickness difference is equal to or greater than a reference value, removing the coated photoresist and performing a photoresist coating process again; And And forming a column spacer pattern by exposing and developing the coated photoresist when the calculated local thickness difference is equal to or less than a reference value.

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