KR20030047172A - Method of forming spacer - Google Patents

Abstract

PURPOSE: A method for forming a spacer is provided to form spacers using an ink jet method capable of preventing misalignment of spacers. CONSTITUTION: A spacer material having a predetermined polarity is prepared. Portions(80) of a substrate on which spacers is formed are charged to have the polarity opposite to the polarity of the spacer material. The spacer material is sprayed onto the substrate through the nozzle(78) of an ink jet head(76) to form spacers(66). The portions of the substrate have the opposite polarity in such a manner that the substrate other than the portions of the substrate on which the spacers are formed is masked to form an electric field only at the portions of the substrate where the spacers are formed.

Description

Spacer formation method {METHOD OF FORMING SPACER}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a spacer forming method capable of maintaining a cell gap uniformly.

In general, a liquid crystal display (hereinafter referred to as "LCD") displays an image by adjusting the light transmittance of the liquid crystal using an electric field. To this end, the LCD includes a liquid crystal panel in which liquid crystal cells are arranged in a matrix, and a driving circuit for driving the liquid crystal panel. The liquid crystal panel is provided with pixel electrodes and a reference electrode, that is, a common electrode, for applying an electric field to each of the liquid crystal cells. The pixel electrode is formed for each liquid crystal cell on the lower substrate, while the common electrode is integrally formed on the front surface of the upper substrate. Each of the pixel electrodes is connected to a thin film transistor (hereinafter referred to as "TFT") used as a switching element. The liquid crystal cell is driven along with the common electrode in accordance with the data signal supplied through the TFT. Such LCDs can be miniaturized compared to CRTs, and are widely used in personal computers and notebook computers, as well as office automation devices such as photocopiers, mobile phones and pagers.

Referring to FIG. 1, a conventional LCD includes a top plate composed of a black matrix 32, a color filter 30, a transparent electrode 28, and an alignment layer 34 sequentially formed on an upper substrate 11, and a lower substrate. (1) a lower plate composed of a TFT, a pixel electrode 22, and an alignment film 24, a spacer 26 formed between the upper plate and the lower plate, and an inner space provided by the upper plate, the lower plate, and the spacer 26. And liquid crystal (not shown) to be injected.

Looking at the manufacturing process of the LCD having such a configuration, the manufacturing process of the top plate is as shown in Figures 2a to 2d.

Referring to FIG. 2A, a black matrix 32 is formed on the upper substrate 11. The black matrix 32 is formed by coating or depositing and patterning an opaque metal such as opaque resin and chromium on the upper substrate 11. In this case, the black matrix 32 is formed in the form of a matrix on the upper substrate 11 to divide the surface of the upper substrate 11 into a plurality of cell regions in which the color filters 30 are to be formed, as well as light between adjacent cells. It serves to prevent interference.

As shown in FIG. 2B, color filters 30A, 30B, and 30C of red, green, and blue primary colors are sequentially formed on the upper substrate 11 on which the black matrix 32 is formed. In this case, each of the three primary color filters 30 is positioned in some of the cell regions divided by the black matrix 32, that is, in a cell region corresponding to one third of the cell region. Each of the three primary color filters 30 absorbs a white light source on the front of the upper substrate 11 on which the black matrix 32 is formed, and then applies a material that transmits only a specific wavelength (red, green, or blue) light and then patterning the color filter 30. It is formed by.

Referring to FIG. 2C, a transparent electrode 28 is formed on the upper substrate 11 on which the black matrix 32 and the color filter 30 are formed. The transparent electrode 28 is supplied with a common voltage and is formed by depositing a transparent conductive film.

After the entirety of the alignment layer 34 is coated on the upper substrate 11 thus formed as shown in FIG. 2D, the upper plate is completed by performing a rubbing process.

In the lower panel, the TFT is formed at the intersection of the gate line 2 and the data line 4 as shown in FIG. 3 and overlaps at least one of the data line 4 and the gate line 2 ( 22 are arranged in a matrix and formed on the lower substrate 1.

In detail, a gate line (not shown) and a gate electrode 6 are formed as shown in FIG. 4A by patterning and depositing a metal film on the lower substrate 1. The gate insulating film 12 is formed by entirely depositing on the lower substrate so as to cover the gate line and the gate electrode 6. By sequentially depositing and patterning the first and second semiconductor materials 14 and 16 on the gate insulating layer 12, the active layer 14 and the ohmic contact layer 16 are formed as shown in FIG. 4B. Subsequently, a metal film is deposited on the gate insulating film 12 and then patterned to form a data line (not shown), a source electrode 8, and a drain electrode 10 as shown in FIG. 4C. The ohmic contact layer 16 is etched to form the active layer 14 so that the active layer 14 is exposed. The contact hole 20 is formed to expose the drain electrode 10, as shown in FIG. 4D, by patterning and then patterning the organic passivation layer 18 on the gate insulating layer. Next, a transparent conductive material is deposited and patterned on the protective layer 18 to form a pixel electrode 22 electrically connected to the drain electrode 10 as shown in FIG. 4E. As shown in FIG. 4F, after the alignment layer 24 is coated on the entire surface of the lower substrate 1 on which the pixel electrode 22 is formed, a rubbing process is performed to complete the lower plate.

As described above, the spherical spacers 26 are scattered on the separately formed upper or lower plates by using a spray nozzle. Thereafter, the LCD is completed by bonding the upper and lower plates together and injecting liquid crystal between the bonded upper and lower plates.

The spacers 26 should be sprayed evenly to maintain a uniform cell gap of the liquid crystal cell. However, in the conventional method of dispersing the spacers 26, the spacers 26 may have non-uniform density because the spacers 26 may not be uniformly distributed on the upper and lower plates. As a result, the cell gap of the liquid crystal cell becomes nonuniform, causing unevenness in the display surface.

In order to solve this problem, a method of forming a spacer using an ink jet (Ink-Jet) has emerged as shown in FIG.

Referring to FIG. 5, the spacer 26 is spread on the upper substrate or the lower substrate through the nozzle 38 of the inkjet head 36.

When dispersing the spacer 26 using an inkjet, the nozzle 38 of the inkjet head 36 is positioned so as to correspond to the position where the spacer 26 should be formed. The spacers 26 ejected through the nozzles 38 of the inkjet head 36 are uniformly formed on the upper plate or the lower plate. However, when the inkjet head 36 ejects the spacer 26 while moving in the scan direction to form the spacer 26, the spacer 26 is not formed at the position 39 at which the actual spacer 26 should be formed. Failure occurs. This may cause a misalignment in which the inkjet head 36 may vibrate as it moves or the spacer 26 may not be formed at a desired position according to the speed of movement of the inkjet head 36.

Accordingly, an object of the present invention is to provide a spacer forming method of a liquid crystal display device which can prevent misalignment.

1 is a cross-sectional view showing a conventional liquid crystal display device.

2A to 2D are sectional views showing the manufacturing process of the upper plate shown in FIG.

3 is a plan view illustrating the liquid crystal display shown in FIG. 1.

4A to 4F are cross-sectional views illustrating a manufacturing process of a lower plate cut along the line “A-A '” shown in FIG. 3.

FIG. 5 is a view showing a method of forming the spacer shown in FIG. 1 using an inkjet. FIG.

6 is a cross-sectional view of an LCD including a spacer according to an exemplary embodiment of the present invention.

7 is a view showing a spacer forming method shown in FIG.

<Explanation of symbols for main parts of drawing>

1, 41: lower substrate 2: gate line

4: data line 6, 46: gate electrode

8, 48 source electrode 10, 50 drain electrode

12, 52: gate insulating film 14, 54: active layer

16, 56: ohmic contact layer 18, 58: protective layer

20, 60: contact hole 22, 62: pixel electrode

24, 34, 64, 74: alignment layer 26, 66: spacer

28, 68: transparent electrode 30, 70: color filter

32, 72: black matrix 36, 76: inkjet head

38, 78: nozzle

In order to achieve the above object, the spacer forming method according to the present invention comprises the steps of providing a spacer material having a predetermined polarity in the liquid crystal display device for forming a spacer using an inkjet, the position of the substrate on which the spacer is to be formed And having a polarity opposite to that of the spacer, and spraying the spacer material onto the substrate through a nozzle of the inkjet head.

Other objects and features of the present invention in addition to the above objects will be apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 6 and 7.

Referring to FIG. 6, the LCD according to the present invention has a polarity opposite to that of the spacer 66 at the formation position of the spacer 66 to be formed so that the spacer 66 is aligned exactly to a desired position.

An upper plate composed of a black matrix 72 and a color filter 70, a transparent electrode 68, and an alignment layer 74 sequentially formed on the upper substrate 51, a TFT array and a pixel formed on the lower substrate 41. Liquid crystals (not shown) injected into the inner space provided by the lower plate composed of the electrode 62 and the alignment layer 64, the spacer 66 formed between the upper plate and the lower plate, and the upper plate, the lower plate and the spacer 66 Equipped.

The color filter 70 formed on the upper plate is a color filter having one of R, G, and B colors, and a plurality of color filters 70 are formed corresponding to each pixel. The black matrix 72 is disposed between each of the R, G, and B color filters 70 to block light so that adjacent pixels do not interfere with color.

In the TFT array formed on the lower plate, the TFTs and the pixels based on pixel electrodes connected to the TFTs are vertically and horizontally arranged, and a plurality of gate lines and data lines electrically connected to the respective TFTs are formed. The gate electrode of the TFT provided near the intersection of the gate line and the data line is branched at the gate line, and the source electrode is branched at the data line. Liquid crystals (not shown) are injected and sealed between the upper substrate and the lower substrate, and a spacer 66 is provided to maintain a constant gap between the upper substrate and the lower substrate.

The spacer 66 is formed on the upper or lower plate to maintain the cell gap of the liquid crystal cell uniformly. The spacer 66 is formed by using an inkjet, and the inkjet can be used to make fine process patterns. The spacer 66 ejected through the nozzle 78 of the inkjet head 76 is exactly formed at a desired position on the upper plate or the lower plate. To this end, the spacer 66 has a predetermined polarity. The polarity opposite to the polarity of the spacer 66 is locally charged at the position 80 where the spacer 66 on the upper or lower plate is to be formed. That is, the electric field is formed only at the position 80 where the spacer 66 is to be formed by covering the mask with an area except the position where the spacer 66 is to be formed. As a result, the attraction force acts because the polarity of the spacer 66 and the polarity of the position where the spacer 66 is to be formed are different from each other. Accordingly, the spacer 66 ejected from the nozzle 78 of the inkjet head 76 may be precisely aligned at the position to be formed by the attraction force.

As described above, the spacer forming method according to the present invention makes the polarity of the spacer different from the polarity of the position where the spacer is to be formed. Accordingly, when the spacer is jetted to the position where the spacer is to be formed using the inkjet, the spacer can be accurately formed at the desired position by the attraction force of the opposite polarity. That is, the spacer forming method according to the present invention can prevent the misalignment when forming the spacer as compared to the conventional.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (2)

In a liquid crystal display device for forming a spacer using an inkjet, Providing a spacer material having the predetermined polarity; Causing the spacer to have a polarity opposite to that of the spacer at the position where the spacer is to be formed; Spraying the spacer material onto the substrate through a nozzle of an inkjet head. The method of claim 1, The polarizing step on the substrate is a spacer forming method, characterized in that to use a mask in the region except the position where the spacer is to be formed.