KR20050043491A - Method for forming a liquid crystal display device - Google Patents

Abstract

The present invention relates to a method of manufacturing a liquid crystal display device through a printing method, comprising: preparing a first substrate on which a thin film transistor array is formed; Preparing a second substrate on which a color filter is formed; Printing a patterned spacer and a sealant on the first or second substrate; And forming a liquid crystal layer between the first and second substrates.

Description

Manufacturing method of liquid crystal display device {METHOD FOR FORMING A LIQUID CRYSTAL DISPLAY DEVICE}

The present invention relates to a method of manufacturing a liquid crystal display device, and more particularly, to a method of forming a spacer and a sealant of a liquid crystal display device by a printing method.

Recently, with the development of various portable electronic devices such as mobile phones, PDAs, and notebook computers, there is a growing demand for flat panel display devices for light and thin applications. Such flat panel displays are being actively researched, such as LCD (Liquid Crystal Display), PDP (Plasma Display Panel), FED (Field Emission Display), VFD (Vacuum Fluorescent Display), but mass production technology, ease of driving means, Liquid crystal display devices (LCDs) are in the spotlight for reasons of implementation.

1 schematically illustrates a cross section of a general liquid crystal display device. As shown in the figure, the liquid crystal display device 1 is composed of a lower substrate 5 and an upper substrate 3 and a liquid crystal layer 7 formed between the lower substrate 5 and the upper substrate 3. . Although the lower substrate 5 is a driving element array substrate, although not shown in the drawing, a plurality of pixels are formed on the lower substrate 5, and each pixel is driven such as a thin film transistor. An element is formed, and the upper substrate 3 is a color filter substrate, and a color filter layer for realizing color is formed. In addition, a pixel electrode and a common electrode are formed on the lower substrate 5 and the upper substrate 3, respectively, and an alignment film for aligning liquid crystal molecules of the liquid crystal layer 7 is coated.

The lower substrate 5 and the upper substrate 3 are bonded by a sealant 8 formed on the outer periphery of the substrate, and have a constant cell gap by a spacer 9 formed between them (the upper substrate and the lower substrate). Keep it. In addition, the liquid crystal layer 7 formed between the substrates 3 and 5 drives the liquid crystal molecules by a driving element formed on the lower substrate 5 to display information by controlling the amount of light passing through the liquid crystal layer. .

The liquid crystal display device configured as described above is formed by a drive element array substrate process of forming a drive element on the lower substrate 5, and the upper substrate 3 is formed by a color filter substrate process of forming a color filter. Thereafter, the liquid crystal display device is completed through a spacer and a sealant forming process.

In the driving device array substrate process, a plurality of gate lines and data lines are formed on the lower substrate 5 to define pixel regions, and the gate lines and the data lines are respectively formed in the pixel regions. After forming the thin film transistor which is the driving element to be connected, the pixel electrode is connected to the thin film transistor to form a pixel electrode for driving the liquid crystal layer as a signal is applied through the thin film transistor.

In addition, the color filter substrate process is performed by forming a black matrix on the upper substrate 3, forming a color filter 2 on the upper substrate, and then forming a common electrode 4.

The spacer may be formed as a ball or a column, and the ball spacer is formed by a scattering method, and the column spacer is formed by depositing or coating an organic polymer material on a substrate, and then selectively It is formed by a photolithography process to remove. However, the scattering method interferes with the alignment of the liquid crystal and lowers the aperture ratio because spacers exist in the pixel region through which light passes. Therefore, in order to improve this, a column spacer for forming a spacer patterned at a desired position has been proposed, but the photolithography process is performed through the application, exposure and development of the photoresist, and the process is complicated because a separate mask is required. There is a problem that the manufacturing cost increases.

In addition, the sealant is to form a gap for liquid crystal injection and to prevent leakage of the injected liquid crystal. A screen printing method of applying a sealant to the entire surface of the screen on which a pattern is formed and printing by pushing with a rubber stick is mainly used. Since the sealant must be applied to the front surface, the production cost due to the waste of the sealant increases.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to provide a method of manufacturing a liquid crystal display device that can simplify the process and reduce the manufacturing cost by forming a spacer and a sealant through a printing method. .

Another object of the present invention is to provide a method of manufacturing a liquid crystal display device which can simplify the process and improve the productivity by forming the spacer and the sealant through one process.

Other objects and features of the present invention will be described in detail in the configuration and claims of the following invention.

The present invention for achieving the above object comprises the steps of preparing a first substrate formed with a thin film transistor array; Preparing a second substrate on which a color filter is formed; Printing a patterned spacer and a sealant on the first or second substrate; And forming a liquid crystal layer between the first and second substrates, wherein forming the spacers and the sealant comprises preparing a printing plate having a plurality of grooves, and forming a spacer and a sealant in the grooves. And filling the ink with the ink and transferring the ink filled in the groove to the substrate.

The preparing of the printing plate may include preparing a first printing plate having a plurality of first grooves; And preparing a second printing plate having a second groove, and filling the spacer and the sealant forming ink into the groove includes applying the spacer and sealant forming ink on the printing plate on which the groove is formed. ; The doctor blade is brought into contact with the surface of the printing plate and then pushed flat to remove the ink remaining in the remaining area except the groove.

In this case, the first and second printing plates may be integrally formed.

In addition, the step of transferring the ink filled in the groove on the substrate transfers the printing roll to the surface of the printing plate filled with ink in the groove and then rotates, thereby transferring the ink filled in the groove to the surface of the printing roll Making a step; The ink transferred on the surface of the printing roll is contacted with the substrate and then rotated, thereby re-transferring the ink formed on the surface of the printing roll onto the substrate.

In addition, the present invention includes the steps of preparing a first substrate having a pixel defined by a plurality of gate lines and data lines, each thin film transistor is formed for each pixel; Preparing a second substrate on which a color filter is formed; Preparing a first printing plate on which a plurality of first grooves are formed; Preparing a preparation 2 printing plate on which a plurality of second grooves are formed; Filling spacer forming ink into the first groove; Filling the sealant forming ink into the second groove; Transferring the spacer and sealant forming ink filled in the first and second grooves onto the first or second substrate; And forming a liquid crystal layer between the first and second substrates.

Transferring the spacer and the ink for forming the sealant filled in the first groove and the second groove on the first or second substrate may be performed by transferring the spacer forming ink filled in the first groove to the first printing roll. Transferring the first printing roll on which the spacer forming ink is formed on the substrate, and then rotating the first printing roll to form the spacer; and filling the second printing roll with the sealant forming ink filled in the second groove. Transferring; And forming a sealant by contacting the second printing roll having the sealant forming ink formed thereon on the substrate and rotating the sealant. In this case, the spacer may be formed on the gate line or the data line of the first substrate.

In the present invention, a printing method is used to form the spacer and sealant of the liquid crystal display device. In particular, gravure offset printing is a printing method in which ink is applied to a concave plate to scrape off excess ink, and printing is known as a printing method in various fields such as publishing, packaging, cellophane, vinyl, polyethylene, and the like. In the present invention, the spacer and the sealant of the liquid crystal display device are fabricated using this printing method.

Since gravure offset printing transfers ink onto a substrate using a printing roll, it is possible to form a pattern by one transfer even in the case of a large display element by using a printing roll corresponding to the area of a desired display element. do.

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

2A to 2D illustrate a method of manufacturing a liquid crystal display device by a printing method, and in particular, are cross-sectional views illustrating a method of manufacturing a spacer and a sealant.

First, as shown in FIG. 2A, a printing plate 100 having a plurality of grooves 102 is prepared, and then ink 104 is filled in the grooves 102. At this time. The ink 104 is a spacer forming ink or a sealant forming ink, and a ball type spacer is mixed with the ink in the spacer forming ink, and a glass fiber capable of maintaining a constant gap in the sealant forming ink. fibers) are mixed. Filling of the ink 104 into the grooves 102 of the printing plate 100 is a state in which the doctor blade 108 is in contact with the substrate 120 after applying the ink 104 to the upper portion of the printing plate 100. By pushing on the Therefore, the ink 104 is filled in the groove 102 by the progress of the doctor blade 108 and the ink 104 remaining on the surface of the printing plate 100 is removed.

As shown in FIG. 2B, the ink 104 filled in the groove 102 of the printing plate 100 is transferred to the surface of the printing roll 120 which rotates in contact with the surface of the printing plate 100. The printing roll 120 is formed in the same width as the width of the substrate to be produced, and has a circumference of the same length as the length of the panel. Therefore, the ink 104 filled in the groove 102 of the printing plate 100 is transferred to the circumferential surface of the printing roll 120 by one rotation.

Thereafter, as illustrated in FIG. 2C, the ink transferred to the printing roll 120 is rotated by rotating the ink 104 transferred to the printing roll 120 in contact with the surface of the substrate 121. 104 is transferred onto the substrate 121, and a desired pattern 125, such as a spacer or sealant, may be formed by applying UV irradiation or heat to the ink 104 transferred to the substrate 121 and drying the same.

When the pattern is formed using the printing method as described above, since the desired pattern can be formed without using the photomask, the photomask process consisting of a series of steps such as mask alignment, exposure and development is omitted. The process time can also be shortened.

3 and 4 illustrate a spacer 125a and a sealant 125b formed on the color filter substrate and the thin film transistor substrate through the printing method as described above.

As shown in FIG. 3, R (red), G (green), and B (blue) color filters 117 are formed on the transparent first substrate 115 on the color filter substrate 121a. A black matrix 118 is formed in the boundary region of the 117 to prevent color mixing between the color filters 117 and to block light leakage. In addition, an overcoat layer 119 for planarization is formed on the color filter 117, and a spacer 125a is formed on the overcoat layer 119. In this case, the spacer 125a is formed in a region corresponding to the black matrix 118. The sealant 126 is formed on the outer side of the substrate 121a to form a gap for injecting liquid crystal and not leak the injected liquid crystal.

Meanwhile, as shown in FIG. 4, the spacers and sealants 125a and 125b may be formed on the thin film transistor substrate 121b. A gate line 131 and a data line 133 are vertically and horizontally arranged on the thin film transistor substrate 121b, and a thin film transistor for driving each pixel is formed at an intersection of the gate line 131 and the data line 133. A TFT is disposed, and gate and data pad portions 131 'and 133' are provided at ends of the gate line 131 and the data line 133 to supply signals thereto. In addition, the pixel P that substantially implements the image is defined by the gate line 131 and the data line 133. The spacer 125a is formed on the gate line 131 and the data line 133 as shown in an enlarged view, and is formed only on the gate line 131 or the data line 133. It may be formed only at the top.

As such, forming the spacer 125a on the black matrix 118 of the color filter substrate 121a or the gate line 131 and the data line 133 of the thin film transistor substrate 121b may affect the image quality of the spacer. To not give.

On the other hand, the sealant 125b is formed on the outer side of the substrate, a liquid crystal inlet for injecting liquid crystal is formed on one side, it can be formed anywhere in the color filter or the thin film transistor substrate (121a, 121b).

As described above, when the spacer 125a and the sealant 125b are formed through the printing method, the printing plate 100 and the printing roll 120 may be manufactured according to the size of the desired display element, and by one transfer Since the pattern can be formed on the substrate 121, the pattern of the large-area display device can also be formed by one process.

Figure 5 shows the printing equipment used for forming the spacer and the sealant of the present invention, it will be described in more detail with respect to the spacer and the sealant manufacturing method through the printing equipment.

As shown in the figure, the printing equipment 250 includes a plurality of printing plates 200 provided to form a spacer and a sealant pattern; A plurality of printing rolls 220 for transferring the spacer and sealant forming ink filled in the printing plate 200 to the substrate 221 and a plurality of ink supply rolls 230 for supplying ink to the printing plate 200. The ink container 240 is provided to fill the ink to provide ink to the ink supply roll 230.

The printing plate 200 is provided with grooves having the same pattern as the spacer and sealant patterns to be formed on the substrate, and the ink supply roll 230 supplies the spacer or sealant forming ink to the printing plate 200, and the printing plate. After the ink is supplied to the 200, a doctor blade (not shown) for removing ink remaining on the surface of the printing plate 200 is further configured.

The printing equipment configured as described above forms a spacer and a sealant on a color filter or a thin film transistor substrate through the following process.

First, after the ink is filled in the ink supply container 240, the ink supply roll 230 is immersed in the ink supply container 240, and then rotated so as to form a spacer ink on the front surface of the ink supply roll 230. Fill it. Subsequently, ink is applied onto the printing plate 200 by rotating the ink supply roll 230 in contact with the printing plate 200 having the same groove 204 as the spacer pattern. Then, by pushing the surface of the printing plate 200 flat using a doctor blade (not shown), the ink is filled in the grooves 204 of the printing plate 200 and all the remaining ink is removed from the surface. do.

At this time, the first ink supply container 240a is filled with a spacer forming ink, the first ink supply roll 230a is supplied with a spacer forming ink, and the spacer forming ink is supplied with a first ink supply roll ( The 230a may contact and rotate the first printing plate 200a to fill the spacer forming ink in the first groove 204a of the first printing plate 200a. In this case, the first groove 204a formed in the first printing plate 200a has the same shape as the spacer pattern.

Similarly, the sealant forming ink is filled in the second ink supply container 240b, and the sealant forming ink is supplied to the second ink supply roll 230b, and the second ink supply roll 230b is formed on the second printing plate (b). By contacting and rotating on 200b, the sealant forming ink is filled in the second groove 204b of the second printing plate 200b. In this case, the second groove 204b has the same shape as the sealant pattern.

In this case, a ball-shaped spacer is mixed with the ink in the spacer forming ink, and a glass fiber having a predetermined height is mixed with the ink in the sealant forming ink.

As described above, the spacer and the sealant ink are filled in the groove of the printing plate 200 by the ink supply roll 230. Thereafter, the first printing roll 220a is rotated in contact with the surface of the first printing plate 200a, so that the ink for forming a spacer is transferred to the surface of the first printing roll 220a, and the first printing roll 220a is transferred. The spacer forming ink transferred to the printing roll 220a is transferred onto the substrate 221 to form a spacer. In this case, as the spacer forming ink transferred to the surface of the first printing roll 220a is brought into contact with the substrate 221 and rotated, a spacer is formed on the substrate 221. Subsequently, the second printing roll 220b is rotated in contact with the surface of the second printing plate 220b so that the sealant forming ink is transferred to the surface of the second printing roll 220b, and the second printing roll ( The sealant forming ink transferred to 220b is applied on the substrate 221 to form a sealant. Subsequently, UV or heat is provided to the substrate 221 to cure the ink.

On the other hand, the printing plate 200 may be formed integrally without being divided into the first and second printing plates (200a, 200b). That is, as shown in FIG. 6, the first groove 204a and the second groove 204b that are identical to the patterns of the spacer and the sealant may be formed in the single printing plate 200, and in this case, the spacer and the sealant are the same. The material must be used, and only one ink supply roll and one printing roll are used. When the spacer and the sealant are formed on the thin film transistor substrate, a planarization film must be further formed on the entire surface of the thin film transistor substrate in order to make the cell gap between the pad portion of the thin film transistor substrate and the pixel region the same.

Therefore, since the spacer and the sealant can be formed simultaneously by one rotation of the printing roll, the process time can be shortened.

As described above, the present invention provides a method of manufacturing a liquid crystal display device, in particular, a method of manufacturing a spacer and a sealant. The manufacturing method of the spacer and the sealant according to the present invention is formed through the printing method, and can simultaneously form the spacer and the sealant in one printing process, simplifying the process and reducing the production cost. That is, in the related art, not only the spacer and the sealant are formed by different processes, but also the photolithography process is required to form the spacer, and the sealant process has to be performed separately. there was. On the other hand, in the present invention, since a desired pattern (spacer pattern, sealant pattern) can be formed in one printing process, production efficiency can be improved through process simplicity and production cost reduction.

In addition, in the above detailed description of the present invention, a method of manufacturing a spacer and a sealant by a gravure offset printing method is illustrated, but the right of the present invention is not limited to the gravure offset printing method. For example, spacers and sealants may be formed using screen printing, inkjet printing, and flexography methods. In addition, the present invention is to form a spacer using a printing method, other examples or modifications of the present invention using this concept should be included in the scope of the present invention.

As described above, the present invention has the effect of improving the productivity by forming a spacer and a sealant through a printing method, simplifying the process and reducing the manufacturing cost.

1 is a cross-sectional view of a general liquid crystal display device.

2a to 2c are process cross-sectional views showing a spacer and a sealant printing method according to the present invention.

3 is a view showing a spacer and a sealant pattern printed on a color filter substrate.

4 is a view showing a spacer and a sealant pattern printed on a thin film transistor substrate.

5 is a view showing the printing equipment according to the present invention.

6 is a view showing that a spacer forming groove and a sealant forming groove are formed in a single printing plate.

*** Explanation of symbols for main parts of drawing ***

100,200,200a, 200b: printing plate

120,200.220a, 220b: printing roll

117: color filter: 118: black matrix

119: overcoat film 121a: color filter substrate

121b: thin film transistor substrate 125a: spacer

125b: sealant 204a: first groove

204b: second groove 230: ink supply roll

Claims (11)

Preparing a first substrate on which a thin film transistor array is formed; Preparing a second substrate on which a color filter is formed; Printing a patterned spacer and a sealant on the first or second substrate; And Forming a liquid crystal layer between the first and second substrates. The method of claim 1, The printing of the spacer and the sealant may include: Preparing a printing plate on which a plurality of grooves are formed; Filling spacers and a sealant forming ink into the grooves; And And transferring the ink filled in the groove to the substrate. The method of claim 2, Preparing the printing plate, Preparing a first printing plate having a plurality of first grooves; And A method of forming a spacer of a liquid crystal display device, comprising the step of preparing a second printing plate having a plurality of second grooves. The method of claim 3, The method of forming a spacer of a liquid crystal display device, characterized in that the first and second printing plate is formed integrally. The method of claim 2, Filling the spacer and the sealant forming ink into the groove, Applying a spacer and a sealant forming ink to an upper portion of the printing plate on which the groove is formed; And removing the ink remaining in the remaining areas except the grooves by contacting the doctor blade with the surface of the printing plate and pushing it flat. The method of claim 2, Transferring the ink filled in the groove on the substrate, Transferring the ink filled in the grooves to the surface of the printing roll by contacting and rotating the printing roll on the surface of the printing plate filled with ink in the grooves; And And rotating the ink transferred on the surface of the printing roll to the substrate and rotating the ink, thereby re-transferring the ink formed on the surface of the printing roll onto the substrate. Preparing a pixel defined by a plurality of gate lines and data lines and a first substrate on which a thin film transistor is formed in each pixel; Preparing a second substrate on which a color filter is formed; Preparing a first printing plate on which a plurality of first grooves are formed; Preparing a second printing plate on which a plurality of second grooves are formed; Filling spacer forming ink into the first groove; Filling the sealant forming ink into the second groove; Transferring the spacer and sealant forming ink filled in the first and second grooves onto the first or second substrate; And And forming a liquid crystal layer between the first and second substrates. The method of claim 7, wherein The transferring of the spacer and the sealant forming ink filled in the first and second grooves onto the first or second substrate may include: Transferring the spacer forming ink filled in the first groove to a first printing roll; Contacting the first printing roll on which the ink for forming spacers is formed on a substrate, and then rotating the first printing roll to form a spacer; Transferring the sealant forming ink filled in the second groove to a second printing roll; And And forming a sealant by contacting the second printing roll having the sealant forming ink formed thereon on the substrate and rotating the sealant. 8. The method of claim 7, further comprising the step of fixing the first and second ink formed on the substrate. The method of claim 7, wherein the spacer is formed on a gate line of the first substrate. The method of claim 7, wherein the spacer is formed on a data line of the first substrate.