KR20060133379A - Apparatus for forming alignment film and forming method thereof using the same - Google Patents

Abstract

An apparatus for forming an alignment layer and a method for forming the alignment layer using the same are provided to reduce the material cost and simplify the process, thereby improving the productive efficiency, by forming the alignment layer in an inkjet type. An inkjet head part(150) is composed of at least one head(150a). The head has a plurality of holes distanced from one another at a predetermined distance. A measuring part collects a printed image of an alignment layer(175), which is formed through the holes. An alignment solution supplying part supplies an alignment solution to the inkjet head part. A connection wire part connects between the inkjet head part and the alignment solution supplying part.

Description

Alignment film forming apparatus and alignment film forming method using the same {APPARATUS FOR FORMING ALIGNMENT FILM AND FORMING METHOD THEREOF USING THE SAME}

1 is an exploded perspective view schematically illustrating a structure of a general liquid crystal display device.

FIG. 2 is a flowchart illustrating a manufacturing method of the liquid crystal display shown in FIG. 1.

3 is a view showing a method of forming an alignment film using a roll printing method.

Figure 4 is a perspective view schematically showing a method of forming an alignment film according to an embodiment of the present invention.

FIG. 5 schematically shows a head of the alignment film forming apparatus shown in FIG. 4. FIG.

6A and 6B show, for example, a coating failure of an alignment film.

7 is a flowchart sequentially illustrating a method of forming an alignment film according to an embodiment of the present invention.

** Description of symbols for the main parts of the drawing **

126: substrate 150: head portion

150a: head 155: nozzle

160: CCD 170: alignment liquid

175: alignment layer

The present invention relates to an alignment film forming apparatus and an alignment film forming method using the same, and more particularly, an alignment film forming apparatus capable of forming a uniform alignment film having a desired thickness through an inkjet method, and reducing material costs and simplifying the process and the same. It relates to the used alignment film formation method.

Recently, with increasing interest in information display and increasing demand for using a portable information carrier, a lightweight flat panel display (FPD), which replaces a conventional display device, a cathode ray tube (CRT), is used. The research and commercialization of Korea is focused on. In particular, the liquid crystal display (LCD) of the flat panel display device is an image representing the image using the optical anisotropy of the liquid crystal, is excellent in resolution, color display and image quality, and is actively applied to notebooks or desktop monitors have.

In general, a liquid crystal display device displays a desired image by individually supplying data signals according to image information to liquid crystal cells arranged in a matrix form to adjust a light transmittance of the liquid crystal cells. to be.

Hereinafter, a liquid crystal display will be described in detail with reference to FIG. 1.

1 is an exploded perspective view schematically illustrating a structure of a general liquid crystal display device.

As shown in the figure, the liquid crystal display device is largely a color filter substrate 5 as a first substrate and an array substrate 10 as a second substrate, and the color filter substrate 5 and an array substrate. It consists of a liquid crystal layer 40 formed between (10).

The color filter substrate 5 includes a color filter C composed of red (R), green (G), and blue (B) sub-color filters (7) and the sub-color filters (7). ) And a black matrix 6 for blocking light passing through the liquid crystal layer 40 and a transparent common electrode 8 for applying a voltage to the liquid crystal layer 40.

The array substrate 10 has gate lines 16 and data lines 17 arranged vertically and horizontally to define the pixel region P. FIG. In this case, a thin film transistor (TFT) T, which is a switching element, is formed in an intersection region of the gate line 16 and the data line 17, and each pixel region P includes a pixel electrode 18. ) Is formed.

The pixel region P is a sub pixel corresponding to one sub color filter 7 of the color filter substrate 5. The color image is a sub-color filter 7 of the red, green, and blue colors. It is obtained by combining. That is, three subpixels of red, green, and blue are gathered to form one pixel, and the thin film transistor T is connected to the red and green subpixels, respectively.

An alignment film (not shown) for aligning the liquid crystal molecules of the liquid crystal layer 40 is coated on the color filter substrate 5 and the array substrate 10 configured as described above.

The manufacturing process of the liquid crystal display device is largely a driving element array substrate process for forming a driving element on the lower array substrate 10 and a color filter substrate process and cell process for forming a color filter on the upper color filter substrate 5. The process of such a liquid crystal display device will be described with reference to FIG. 2 as follows.

First, a plurality of gate lines and data lines arranged on a lower substrate to define a pixel region are formed by an array process, and thin film transistors, which are driving elements connected to the gate lines and data lines, are formed in each of the pixel regions (S101). ). In addition, the pixel electrode is connected to the thin film transistor through the array process to drive the liquid crystal layer as a signal is applied through the thin film transistor.

In addition, the upper substrate is formed with a color filter layer and a common electrode composed of sub-color filters of red, green, and blue that implement color by the color filter process (S104).

Subsequently, after the alignment layer is applied to the upper and lower substrates, an alignment control force or surface fixation force (ie, a pretilt angel and an orientation direction) is applied to the liquid crystal molecules of the liquid crystal layer formed between the upper substrate and the lower substrate. The alignment layer is rubbed in order to provide it (S102, S105). Then, the spacers for maintaining a constant cell gap on the lower substrate is dispersed and a sealing material is applied to the outer portion of the upper substrate, and then the pressure is applied to the lower substrate and the upper substrate (S103, S106, S107).

On the other hand, the lower substrate and the upper substrate is composed of a large area glass substrate. In other words, a plurality of panel regions are formed on a large glass substrate, and a thin film transistor and a color filter layer, which are driving elements, are formed in each of the panel regions, so that the glass substrate must be cut and processed to produce a single liquid crystal panel. (S108). Thereafter, liquid crystal is injected into the individual liquid crystal panel processed as described above through the liquid crystal inlet, and the liquid crystal inlet is encapsulated to form a liquid crystal layer, and then the liquid crystal display is manufactured by inspecting each liquid crystal panel (S109 and S110). .

The liquid crystal display device manufactured through the above process uses the electro-optic effect of the liquid crystal. Since the electro-optic effect is determined by the anisotropy of the liquid crystal itself and the molecular arrangement state of the liquid crystal, the control of the molecular arrangement of the liquid crystal is It will greatly affect the stabilization of the display quality of the liquid crystal display device.

Therefore, the alignment film forming process for more effectively aligning the liquid crystal molecules is very important in relation to the image quality characteristics in the liquid crystal cell process.

3 is a view illustrating a method of forming an alignment film using a roll printing method. As illustrated, a general alignment film is formed using a printing method using a plurality of rolls. In other words, the annealing roll 22 supplied between the cylindrical anneal roll 22 and the doctor roll 23 is rotated as the anneal roll 22 and the doctor roll 23 rotate. Evenly spread over. At this time, the supply of the alignment liquid 24 is made by the dispenser 1 in the form of a syringe.

The anneal roll 22 is rotated in contact with the printing roll 24 having the rubber plate 25 attached to a predetermined area of the surface so that the alignment liquid 24 on the surface of the anneal roll 22 is the rubber plate 25. Is transferred to. The rubber plate 25 corresponds to the substrate 26 to which the alignment liquid 24 is to be applied, and a master pattern is formed to selectively print the alignment layer on the substrate 26.

At this time, as the printing table 27 on which the substrate 26 is mounted moves in contact with the printing roll 24, the alignment liquid 24 transferred to the rubber plate 25 is retransmitted onto the substrate 26 to form an alignment layer. Will be formed. Usually the thickness of the alignment film is 500 ~ 1000 ?? On the same board, 100 ?? Since the defects such as unevenness due to the alignment unevenness may occur on the screen of the liquid crystal display device due to the difference in thickness, the uniform coating of the alignment layer becomes an important factor that determines the characteristics of the screen.

However, in the roll printing method as described above, since the dispenser 1 supplies the alignment liquid 24 on the annex roll 22 while moving from side to side on the annex 22 roll, an alignment film having a uniform thickness is formed. There is a limit, and in particular, as the substrate 26 is enlarged, it becomes more difficult to uniformly apply the alignment film. In addition, since the alignment liquids 24 transferred to the rubber plate 25 are not all transferred to the substrate 26, the waste liquid is more discarded than the alignment liquid 26 that is substantially added to the substrate 26, resulting in severe material waste. There is a problem.

In addition, as the size of the substrate 26 is changed, the rolls (doctor roll 23, anilox roll 22, printing roll 24) must be replaced, and the process is cumbersome because the cleaning process must be performed periodically. There was a problem of low productivity.

In addition, as the substrate 26 is enlarged, the size of the roll printing equipment (anneal roll 22, print roll 24) must also increase, resulting in the enlargement of the equipment according to the enlargement of the substrate 26, the alignment film It becomes more difficult to maintain a uniform thickness of.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, by forming the alignment film by applying the necessary amount of the alignment liquid in a desired position by the inkjet method, it is possible to form an alignment film of uniform thickness over the entire substrate and to reduce material cost waste An object of the present invention is to provide an alignment film forming apparatus and an alignment film forming method using the same.

Another object of the present invention is to provide an alignment film forming apparatus and an alignment film forming method using the same, which can shorten the time required for pitch adjustment and realize a uniform thickness by realizing automation of pitch management using a CCD.

Another object of the present invention is to provide a method of manufacturing a liquid crystal display device using the alignment film forming apparatus and the alignment film forming method.

Further objects and features of the present invention will be described in the configuration and claims of the invention which will be described later.

In order to achieve the above object, the alignment film forming apparatus of the present invention is composed of at least one head, the head is an inkjet head portion having a plurality of holes spaced at regular intervals; And a measuring device for collecting a printed image of the alignment film applied through the hole.

In addition, the alignment film forming method of the present invention comprises the steps of preparing a test substrate; Test printing the alignment film on the surface of the test substrate using an alignment film forming apparatus; Collecting a print image of the alignment film through a measuring device; Analyzing the collected information and feeding it back to the alignment layer forming apparatus; Adjusting the head position of the alignment film forming apparatus based on the analyzed information; And loading the new substrate to start printing the alignment film.

In addition, another alignment film forming method of the present invention comprises the steps of printing an alignment film on the surface of the substrate using the alignment film forming apparatus; Loading a test substrate into the alignment film forming apparatus when the alignment film is printed on a predetermined number of substrates or when there is a change in the substrate model; Test printing an alignment layer on a surface of the test substrate; Collecting a print image of the alignment film through a measuring device; Analyzing the collected information and feeding it back to the alignment layer forming apparatus; Adjusting the head position of the alignment film forming apparatus based on the analyzed information; And loading the new substrate to start printing the alignment film.

In addition, the manufacturing method of the liquid crystal display device of the present invention comprises the steps of providing a first substrate and a second substrate; Forming a switching element on the first substrate through an array process, and forming a color filter on the second substrate through a color filter process; Printing an alignment film on a surface of the substrates using an alignment film forming apparatus; Loading a test substrate into the alignment film forming apparatus when the alignment film is printed on a predetermined number of substrates or when there is a change in the substrate model; Test printing an alignment layer on a surface of the test substrate; Collecting a print image of the alignment film through a measuring device; Analyzing the collected information and feeding it back to the alignment layer forming apparatus; Adjusting the head position of the alignment film forming apparatus based on the analyzed information; Loading a new substrate to perform alignment film printing; And bonding the first substrate and the second substrate on which the alignment layer is formed.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the alignment film forming apparatus and an alignment film forming method using the same according to the present invention.

4 is a view schematically showing a method of forming an alignment film according to an embodiment of the present invention.

As shown in the drawing, a mother substrate 126 on which a plurality of thin film transistor array substrates or color filter substrates are arranged is prepared.

The mother substrate 126 is subjected to a thin film transistor array process or a color filter process. In the thin film transistor array process, after preparing a transparent first substrate, a plurality of gate lines arranged vertically and horizontally on the substrate define pixel regions. And a data line, and a thin film transistor, which is a driving element connected to the gate line and the data line, is formed in each of the pixel regions, and then a passivation layer is formed over the thin film transistor and the pixel region, and a transparent pixel electrode is formed thereon. To form.

In the color filter process, a transparent second substrate is prepared, a black matrix is formed on the substrate, a color filter is formed in a region corresponding to the pixel region, and a common electrode is formed thereon.

The alignment layer 175 is formed by dropping the alignment liquid 170 on the mother substrate 126 manufactured through the above process using the alignment liquid dropping means. In this case, the alignment liquid dropping means is an ink jet system, and the ink jet head 150 dropping the alignment liquid 170 directly onto the mother substrate 126 and the alignment liquid 170 is supplied to the ink jet head 150. It is composed of a liquid supply unit (not shown) and a connection wiring unit (not shown) for mechanically connecting the inkjet head unit 150 and the alignment liquid supply unit.

The inkjet head unit 150 includes at least one head 150a, and a plurality of holes (not shown) are formed in each head 150a. By the opening and closing of the hole, the supply amount of the alignment liquid 170 applied to the mother substrate 126 and the dropping position of the alignment liquid 170 are adjusted. In addition, the process time of the alignment layer 174 may be adjusted by adjusting the number of holes.

At this time, although not shown in the drawing, when nitrogen gas (N ₂ ) is supplied to the alignment liquid supply unit in which the alignment liquid 170 is stored, the pressure of the alignment liquid supply unit is increased by the nitrogen gas, and the alignment liquid ( 170 is introduced into the inkjet head 150 through the connection wiring. In this case, the introduced alignment liquid 170 is dropped on the mother substrate 126 through the hole formed in the inkjet head 150. The alignment liquid 170 discharged through the hole is dropped on the mother substrate 126 to form an alignment layer 170 having a uniform thickness.

The alignment layer 170 is formed as the stage (not shown) or the head 150a on which the mother substrate 126 is positioned moves, and the alignment layer is selectively formed in the region of the mother substrate 126 passing through the inkjet head unit 150. 175 is formed. In this case, the inkjet head unit 150 closes a part of the hole formed in the inkjet head unit 150 during the movement of the stage while supplying the alignment liquid 170 on the mother substrate 126, thereby forming an image on the mother substrate 126. An alignment film 175 may be optionally formed on the substrate. Here, the region in which the alignment layer 175 is formed is substantially a region in which a thin film transistor array substrate or a color filter substrate is formed.

As described above, the inkjet head unit 150 includes at least one head 150a having a plurality of holes to freely adjust the dropping area of the alignment liquid 170 according to the size of the mother substrate 126. Therefore, as the mother substrate 126 is enlarged, the number of the heads 150a can be increased to easily cope with the enlargement of the mother substrate.

FIG. 5 is a view schematically showing a head of the alignment film forming apparatus shown in FIG. 4.

As shown in the drawing, the head 150a has a plurality of holes 155 spaced apart from each other by a predetermined distance d1, and the alignment liquid discharged through the holes 155 is dropped onto the substrate. Accordingly, the uniformity of the thickness of the alignment layer and the thickness of the alignment layer formed on the substrate may be adjusted by changing the size and the spacing d1 of the hole 155.

In addition, since the holes 155 can be controlled to be opened and closed for each of the alignment layers, the holes 155 are individually opened and closed in a multi model glass (MGG) in which two or more substrate models are formed. Can be formed.

As described above, the formation of the alignment layer using the inkjet system can easily cope with various substrate models and the enlargement of the substrate, and since only the required amount of the alignment liquid is directly dropped on the substrate, the consumption of the alignment liquid can be minimized, so that the liquid crystal display The manufacturing cost of the device can be significantly reduced.

On the other hand, the narrower the interval of d1 is, the more advantageous it is to form the alignment film in a uniform thickness. However, since the hole 155 has a constant size, there is a limit to narrowing d1.

In order to solve this problem, there is a method of shifting or reciprocating the head 150a when the alignment layer is formed.

Alternatively, as illustrated in the drawing, the arrangement of the holes 155 may be arranged in a zigzag form, thereby reducing the distance between the holes 155 through which the alignment liquid comes out without shifting the head 150a.

In general, a connection wiring part for mechanically connecting the head 150a and the alignment liquid supply part is located at left and right ends of the head 150a, so that the pitch dp between the heads 150a (that is, between neighboring heads 150a). Spacing interval between the holes 155 may not maintain the same spacing as the spacing interval d1.

Accordingly, in order to maintain the pitch dp between the heads 150a at the same interval as the spacing d1, neighboring heads 150a are alternately arranged so that a predetermined area overlaps.

In the inkjet type alignment film forming apparatus configured as described above, it is important to manage the pitch dp between the heads 150a in order to secure printing uniformity. The phenomenon occurs.

6A to 6B are diagrams showing, for example, application failure of the alignment film.

First, in the inkjet type alignment film forming apparatus, when the pitch between neighboring heads is smaller than a predetermined spacing interval, for example, when nozzles of neighboring heads overlap, as shown in FIG. 6A, the printed image of the alignment film ( The coating failure in which the thick line 190a is generated at 180 appears. The overlapped areas of the nozzles of the neighboring heads are overlapped with the printed image 180 of the alignment layer, and are represented by one thick line 190a.

In addition, when the pitch between neighboring heads is larger than the predetermined spacing interval, as shown in FIG. 6B, coating defects in which the thin line 190b occurs in the printed image 180 of the alignment layer may appear. In this case, two thin lines 190b appear between the printed images 180 when the distance between the nozzles of the neighboring heads is far from the predetermined distance.

As described above, the management of the pitch between the heads is very important. In this embodiment, as shown in FIG. 4, a measuring device such as a CCD (Charge Coupled Device) 160 is installed in the alignment film forming apparatus, thereby By collecting and analyzing the images, the alignment layer 175 can be uniformly printed.

Immediately after the alignment film 175 is printed on the substrate 126, the pitch is measured by scanning with the CCD 160, and the results are fed back to the printing apparatus to automatically adjust the pitch during printing of the next substrate 126. You lose. The measurement of the pitch as described above is made by a predetermined period or the operator's choice, it will be described in detail with reference to the drawings.

7 is a flowchart sequentially illustrating a method of forming an alignment layer according to an embodiment of the present invention.

When the alignment film is printed on the predetermined number of substrates or the substrate model is changed through the alignment film forming apparatus of the present embodiment, the test substrate for test printing is loaded on the table of the alignment film forming apparatus (S201).

When the alignment film is printed on a predetermined number of substrates as described above, test printing is performed to check whether the head is turned. When the substrate model is changed, the head of the alignment film printing apparatus is adjusted according to the size and shape of the changed substrate. Since this is necessary, test printing of the present embodiment is performed (S202).

After forming the alignment layer on the test substrate through the same alignment layer forming method, the printed image of the alignment layer is collected by a measuring device such as a CCD (S203).

The measuring device measures the pitch between the centers of the alignment layer applied through the nozzle of the head, and when the collected information is analyzed using an analysis device such as a computer (S204).

Thereafter, the position of the measured head is compared with the position of the set head, and the difference is fed back to the alignment layer forming apparatus to adjust the position of the head (S205).

The pitch data fed back as described above is automatically input to the alignment film forming apparatus and the printing of the alignment film is started by applying the alignment liquid to the new substrate through the adjusted head (S206).

Many details are set forth in the foregoing description but should be construed as illustrative of preferred embodiments rather than to limit the scope of the invention. Therefore, the invention should not be defined by the described embodiments, but should be defined by the claims and their equivalents.

As described above, in the alignment film forming apparatus and the alignment film forming method using the same according to the present invention, by forming the alignment film using the inkjet method, it is possible to reduce the material cost and simplify the process to improve the production efficiency.

In addition, the pitch confirmation is facilitated by realizing the automation of the pitch management immediately after the formation of the alignment layer, and the time taken to adjust the pitch can be significantly reduced compared to the conventional one.

Claims (24)

An inkjet head unit including at least one head, the head having a plurality of holes spaced at regular intervals; And And a measuring device for collecting a printed image of the alignment film applied through the hole. The alignment film forming apparatus according to claim 1, further comprising an alignment solution supply unit for supplying an alignment solution to the inkjet head unit. 3. The alignment film forming apparatus according to claim 2, further comprising a connection wiring portion for connecting the inkjet head portion and the alignment liquid supply portion. 2. The alignment film forming apparatus as claimed in claim 1, wherein the holes formed in the head are arranged in a zigzag form. The alignment film forming apparatus of claim 1, further comprising an analyzer configured to analyze the collected image to compare the measured head position with a set head position and feed back the difference to the alignment film forming apparatus. 2. An alignment film forming apparatus according to claim 1, wherein said measuring device comprises a CCD. 2. An alignment film forming apparatus according to claim 1, wherein said measuring device is provided in an alignment film forming apparatus. Preparing a test substrate; Test printing the alignment film on the surface of the test substrate using an alignment film forming apparatus; Collecting a print image of the alignment film through a measuring device; Analyzing the collected information and feeding it back to the alignment layer forming apparatus; Adjusting the head position of the alignment film forming apparatus based on the analyzed information; And Loading a new substrate to start printing the alignment film. The method of claim 8, wherein the test printing is performed when the alignment film is printed on a predetermined number of substrates or when there is a change in the substrate model. 9. The method of claim 8, wherein the measuring device comprises a CCD. 9. An alignment film forming method according to claim 8, wherein said measuring device is provided in an alignment film forming device. 10. The method of claim 8, wherein the collecting of the printed image comprises measuring a pitch between the centers of the alignment films applied through the head of the alignment film forming apparatus. 13. The method of claim 12, wherein the measured pitch is analyzed to compare the measured head position with the set head position and feed back the difference to the alignment film forming apparatus. Printing the alignment film on the surface of the substrate using the alignment film forming apparatus; Loading a test substrate into the alignment film forming apparatus when the alignment film is printed on a predetermined number of substrates or when there is a change in the substrate model; Test printing an alignment layer on a surface of the test substrate; Collecting a print image of the alignment film through a measuring device; Analyzing the collected information and feeding it back to the alignment layer forming apparatus; Adjusting the head position of the alignment film forming apparatus based on the analyzed information; And Loading a new substrate to start printing the alignment film. 15. The method of claim 14, wherein the measuring device comprises a CCD. 15. The method of claim 14, wherein the measuring device is provided in the alignment film forming apparatus. 15. The method of claim 14, wherein the collecting of the printed image comprises measuring a pitch between the centers of the alignment films applied through the head of the alignment film forming apparatus. 18. The method of claim 17, wherein the measured pitch is analyzed to compare the measured head position with the set head position and feed back the difference to the alignment film forming apparatus. Providing a first substrate and a second substrate; Forming a switching element on the first substrate through an array process, and forming a color filter on the second substrate through a color filter process; Printing an alignment film on a surface of the substrates using an alignment film forming apparatus; Loading a test substrate into the alignment film forming apparatus when the alignment film is printed on a predetermined number of substrates or when there is a change in the substrate model; Test printing an alignment layer on a surface of the test substrate; Collecting a print image of the alignment film through a measuring device; Analyzing the collected information and feeding it back to the alignment layer forming apparatus; Adjusting the head position of the alignment film forming apparatus based on the analyzed information; Loading a new substrate to perform alignment film printing; And And attaching the first substrate and the second substrate on which the alignment layer is formed. 20. The method of claim 19, further comprising forming a liquid crystal layer between the first substrate and the second substrate. 20. The manufacturing method of a liquid crystal display device according to claim 19, wherein said measuring device comprises a CCD. 20. The method of manufacturing a liquid crystal display device according to claim 19, wherein the measuring device is provided in an alignment film forming device. 20. The method of claim 19, wherein the collecting of the printed image comprises measuring a pitch between the centers of the alignment layers applied through the head of the alignment layer forming apparatus. 24. The method of claim 23, wherein the measured pitch is analyzed to compare the measured head position with the set head position and feed back the difference to the alignment layer forming apparatus.

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