KR20030047022A - A method for fabricating color filter substrate for LCD - Google Patents

Abstract

PURPOSE: A method for fabricating a color filter substrate for a liquid crystal display is provided to simplify a color filter substrate fabrication process to improve product yield. CONSTITUTION: A black matrix(106) and color filters(108a,108b,108c) are formed on a substrate(100). An overcoat layer(126) is formed on the overall surface of the substrate. A transparent common electrode(118) is formed on the color filter. An alignment film(120) is formed on the common electrode. A plurality of photosensitive organic layer patterns are formed on the alignment film using ink jet. Light is irradiated onto the bottom of the substrate on which the plurality of photosensitive organic layer patterns are formed. The photosensitive organic layer patterns exposed to the light are developed, to form spacers(124) on the black matrix.

Description

A method for fabricating color filter substrate for LCD}

The present invention relates to a liquid crystal display device, and to a manufacturing method of a color filter substrate for a liquid crystal display device.

Hereinafter, a structure and operation characteristics thereof according to the liquid crystal panel of the liquid crystal display will be described with reference to FIG. 1.

1 is a view schematically showing a general liquid crystal panel.

As shown, the liquid crystal panel includes a color filter 7 including a black matrix 6 and a sub-color filter (red, green, blue) 8 and a common electrode 18 transparent on the color filter 7. The upper substrate 5 formed thereon, the lower substrate 22 on which the pixel region P and the array wiring including the switching electrode T and the pixel electrode 17 formed on the pixel region are formed. The liquid crystal 14 is filled between 5) and the lower substrate 22.

The lower substrate 22 is also referred to as an array substrate, and the thin film transistor T, which is a switching element, is positioned in a matrix type, and the gate wiring 13 and the data wiring 15 passing through the plurality of thin film transistors cross each other. Is formed.

The pixel area P is an area defined by the gate line 13 and the data line 15 intersecting each other. The pixel electrode 17 formed on the pixel region P uses a transparent conductive metal having relatively high light transmittance, such as indium-tin-oxide (ITO).

A liquid crystal panel manufactured with the above-described configuration will be briefly described below with reference to flowchart 2.

2 is a flowchart illustrating a manufacturing process of a liquid crystal cell that is generally applied. In the st1 step, a lower substrate is prepared first. A plurality of thin film transistors (TFTs) are arranged on the lower substrate as switching elements, and pixel electrodes are formed in one-to-one correspondence with the TFTs.

The st2 step is to form an alignment layer on the lower substrate.

The alignment layer formation includes a coating and rubbing process of the polymer thin film. The polymer thin film is generally referred to as an alignment layer, and must be deposited with a uniform thickness over the entire lower substrate, and rubbing should be uniform.

The rubbing is a main process of determining the initial alignment direction of the liquid crystal. The rubbing of the alignment layer enables the normal liquid crystal to be driven and has a uniform display characteristic.

In general, a polyimide series, which is an organic organic alignment layer, is mainly used for the alignment layer.

The rubbing process refers to rubbing the alignment layer in a predetermined direction using a cloth, and the liquid crystal molecules are aligned according to the rubbing direction.

The st3 step represents a process of printing a seal pattern.

The seal pattern in the liquid crystal cell has two functions of forming a gap for injecting the liquid crystal and preventing leaking of the injected liquid crystal. The seal pattern is a step of uniformly forming a thermosetting resin into a desired pattern, and screen printing has become mainstream.

st4 step is to remove spacer It shows the process of spreading.

In the manufacturing process of the liquid crystal cell, a spacer having a constant size is used to maintain a precise and uniform gap between the upper substrate and the lower substrate. Therefore, the spacer should be dispersed at a uniform density with respect to the lower substrate, and the dispersion method can be broadly divided into a wet dispersion method in which a spacer is mixed by spraying alcohol and the like and a dry dispersion method in which only the spacer is dispersed.

In addition, dry dispersion is divided into electrostatic spraying using static electricity and antistatic spraying using gas pressure. In the liquid crystal cell having a structure susceptible to static electricity, the electrostatic spraying method is frequently used.

After the spacer spreading process is completed, the process proceeds to the bonding process of the upper substrate as the color filter substrate and the lower substrate as the thin film transistor array substrate (st5).

The joining arrangement of the upper substrate and the lower substrate is determined by the margin given in the design of each substrate, and usually a precision of several μm is required. If the two substrates are out of the bonding error range, light leaks out, so that the desired image quality characteristics cannot be expected when the liquid crystal cell is driven.

The st6 step is a step of cutting the liquid crystal cell prepared in the st1 to st5 step into a unit cell. In general, a liquid crystal cell undergoes a process of forming a plurality of liquid crystal cells on a large area glass substrate and then separating them into a single liquid crystal cell, which is a cell cutting process.

In the initial manufacturing process of the liquid crystal display device, a process of cutting several cells at the same time and then cutting them into cell units is performed. However, as cell sizes increase, the cells are cut into unit cells and then a liquid crystal is injected.

The cell cutting process is composed of a diamond pen having a hardness higher than that of a glass substrate, and a scribe process for forming a cutting line on the surface of the substrate and a break process for applying force.

The st7 step is a step of injecting liquid crystal into the liquid crystal cell cut into each unit cell.

The unit liquid crystal cell has a gap of several μm in an area of several hundred cm ² . Therefore, the vacuum injection method using the pressure difference between the inside and outside of the cell is most widely used as a method of effectively injecting the liquid crystal into the cell of such a structure.

In the above-described process, the spacer mainly uses a separate standardized spacer as described, but this method has many limitations in the method of dispersing the spacer.

Therefore, many methods of patterning and forming spacers during the manufacturing process of the substrate have been studied.

The spacer directly patterned on the substrate may be formed on the lower substrate or the upper substrate (color filter substrate). When the spacer is formed on the lower substrate, the spacer is generally formed on the array wiring of the lower substrate.

As an example of forming the spacer, a method of forming a spacer using a photosensitive material on an upper substrate will be described.

Hereinafter, a conventional patterned spacer forming method will be described with reference to the processes of FIGS. 3A to 3F.

First, as shown in FIG. 3A, a black matrix is formed on the transparent insulating substrate 5.

In general, the black matrix 6 is positioned between red / green / blue patterns, which are sub color filters, and shields light passing through a reverse tilt domain formed around the pixel electrode 17 of FIG. 1. It forms for the purpose of doing it.

In general, as the material of the black matrix 6, a metal thin film such as chromium (Cr) having an optical density of 3.5 or more, or a carbon-based organic material is mainly used, and chromium (Cr) / chromium oxide ( Black matrices of two-layer films such as CrO _X ) may be used for the purpose of low reflection.

Thus, according to the purpose, any of the above-mentioned materials is used to form the black matrix 6.

In this case, the portion 17a on which the color filter corresponding to the pixel electrode (17 of FIG. 1) formed on the array substrate 22 of FIG. 1 is to be formed is etched by an area smaller than the pixel electrode.

3B is a view illustrating a color filter forming process using color resins having red / green / blue colors.

The main component of the color resin is composed of a photopolymerizable photosensitive composition such as a photopolymerization initiator, a monomer, a binder, and an organic pigment having a red / green / blue or similar color.

First, a red, green or blue color resin having a red color is applied to the entire surface of the substrate 5 on which the black matrix 6 is formed, and then selectively exposed to a desired area. The red sub-color filter 8a is formed in this. (The order of coloring Randomly The color order of red (R), green (G) and blue (B) will be explained.

Next, a green color resin is coated on the entire surface of the substrate 5 on which the red color filter 8a is formed and then selectively exposed to form a green color filter 8b.

Subsequently, a blue color resin is coated on the entire surface of the substrate 5 on which the red and green color filters 8a and 8b are formed and then selectively exposed to form a blue color filter 8c.

3C is a step of planarizing the surface of the substrate on which the color filter is formed. In order to planarize the substrate 5 on which the color filters 8a, 8b, and 8c are formed, a transparent resin having an insulating property is coated on the substrate 5 to form an overcoat layer 26. .

3D is a step of forming an electrode on the color filter.

In general, when the color filter substrate 5 is used as the upper substrate of the liquid crystal panel, the upper layer of the color filter substrate 5 forms the transparent electrode 18.

In this case, a common voltage flows through the transparent electrode 18, and serves to drive the liquid crystal 14 together with the pixel voltage flowing through the pixel electrode 17 of FIG. 1.

Therefore, a selected one of a transparent conductive metal group consisting of indium tin oxide (ITO) and indium zinc oxide (IZO) having excellent transmittance is deposited on the entire surface of the substrate 5 on which the overcoat layer 26 is formed, and the pattern is deposited. Thus, a common electrode 18 is formed.

Next, FIG. 3E illustrates a process of forming a spacer, and forms a photosensitive organic layer 28 by coating a photosensitive organic material on the entire surface of the substrate 5 on which the common electrode 18 is formed. In this case, the photosensitive organic material generally uses a negative type.

The mask 30 including the transmission part E and the blocking part F is positioned on the substrate 5 on which the photosensitive organic film 28 is formed. The transmission part E may be positioned to correspond to a portion where a spacer pattern is to be formed on the substrate 5.

Next, after irradiating light from the upper portion of the mask 30, the photosensitive organic layer 28 is developed.

As a result of the above, as shown in FIG. 3F, a spacer 40 patterned into a predetermined shape is formed.

Spacers can be fabricated directly on the substrate by the process described above.

However, the conventional method for forming a spacer uses a method of coating a material forming the spacer on the entire surface of the substrate and then developing it.

At this time, 90% of the spacer forming material coated on the substrate is removed during the developing process. As a result, the remaining 90% of the spacer forming material is wasted in order to form as much as 10% of the spacer forming material in a predetermined pattern, resulting in an increase in material cost.

The present invention has been proposed for the purpose of solving the above-described problems, and when the spacer material is coated, the spacer material is coated only on a desired area by using an inkjet method and patterned through back exposure.

In this way, the mask process can be omitted together with the effect of reducing the loss of material costs, thereby increasing the price competitiveness of the product and improving the yield of the product through the process simplification.

1 is a view schematically showing a liquid crystal panel,

2 is a flowchart illustrating a procedure of manufacturing a liquid crystal panel;

3A to 3F are cross-sectional views illustrating a process sequence of the prior art by cutting along II-II of FIG. 1, which is an upper substrate of a liquid crystal panel.

4A to 4F are cross-sectional views illustrating a process sequence of the present invention by cutting along II-II of FIG. 1, which is an upper substrate of a liquid crystal panel.

5 is a cross-sectional view taken along the line VV of FIG. 1, which is a lower substrate of the liquid crystal panel.

<Short description of the symbols in the drawings>

100: substrate 108a, b, c: red / green / blue sub color filter

118: common electrode 120: alignment layer

122 spacer film 126 planarization film

130: inkjet head

In the spacer forming method according to the present invention for achieving the above object, in the liquid crystal display spacer forming method formed on the first substrate or the second substrate to maintain a gap between the first substrate and the second substrate, Forming a spacer pattern film in an inkjet method only on any spacer forming region defined in the substrate; Irradiating light from a lower portion of the substrate on which the spacer pattern layer is formed; Developing the spacer pattern layer to form a spacer.

The spacer forming material uses a positive photosensitive organic material.

The color filter forming method according to the present invention includes the steps of forming a color filter composed of a black matrix and a sub color on a substrate; Forming a transparent common electrode on the color filter; Forming an alignment layer on the common electrode; Forming a plurality of photosensitive organic layer patterns on the alignment layer on the black matrix by using inkjet; Irradiating light from a lower portion of the substrate on which the plurality of photosensitive organic layer patterns are formed; Developing the photosensitive organic film pattern irradiated with light to form a spacer on the black matrix.

According to an aspect of the present invention, there is provided a method of forming an array substrate, the method comprising: forming a plurality of gate interconnections and data interconnections defining a pixel region by crossing each other on a substrate; Forming a thin film transistor including a gate electrode, an active layer, a source electrode, and a drain electrode in a region where the gate wiring and the data wiring cross each other; Forming a transparent pixel electrode in the pixel region while being in contact with the drain electrode of the thin film transistor; Forming an alignment layer on the entire surface of the substrate on which the pixel electrode is formed; Forming a plurality of organic layer patterns on the alignment layer on the gate line and the data line by using inkjet;

Irradiating light from a lower portion of the substrate on which the plurality of photosensitive organic layer patterns are formed; Developing the photosensitive organic film pattern to which the light is irradiated, and forming a spacer having a predetermined shape on the gate line and the data line.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

Example

The present invention is characterized in that when forming a patterned spacer on a color filter substrate for a liquid crystal display, the organic material is coated only on a desired area by an ink jet method, and the organic material is exposed to the back surface to pattern the spacer. .

4A to 4F are cross-sectional views sequentially illustrating a manufacturing process of a color filter substrate for a liquid crystal display device according to the present invention.

First, as shown in FIG. 4A, the black matrix 106 and the red / green / blue sub color filters 108a, 108b, and 108c are formed on the transparent insulating substrate 100.

The method of forming the sub color filter has been described in the related art.

4B is a step of planarizing the surface of the substrate on which the color filter is formed. In order to planarize the substrate 100 on which the color filters 108a, 108b and 108c are formed, an overcoat layer 126 is formed by applying a transparent resin having an insulating property on the substrate 100. .

4C is a step of forming an electrode on the color filter.

In general, when the color filter substrate 100 is used as the upper substrate of the liquid crystal panel, the upper layer of the color filter substrate 100 forms the transparent electrode 118.

In this case, a common voltage flows through the transparent electrode 118, and serves to drive the liquid crystal 14 together with the pixel voltage flowing through the pixel electrode 17 of FIG. 1.

Therefore, a selected one of a transparent conductive metal group composed of indium tin oxide (ITO) and indium zinc oxide (IZO) having excellent transmittance is deposited on the entire surface of the substrate 100 on which the overcoat layer 126 is formed, and the pattern is deposited. Thus, a common electrode 118 is formed.

In the above configuration, the planarization film is not an essential component and may be omitted depending on conditions.

Next, as shown in FIG. 4D, an alignment layer 120 is formed on the common electrode 118 to align the liquid crystal.

Next, as illustrated in FIG. 4E, a positive photosensitive spacer forming material 122 is coated on the alignment layer 120 on the black matrix 106 by an ink jet method.

In detail, the inkjet head 130 is positioned on the black matrix 106 and the spacer forming material is dropped by an amount necessary for a desired area to coat a plurality of spacer layers 122 having a predetermined area.

Next, light L2 is exposed to the lower portion of the substrate 100 coated with the space film 122 to expose the light.

Next, as shown in FIG. 4F, when the exposed spacer layer 122 is developed, only a portion located above the black matrix 106 remains.

Finally, the spacer 124 having a predetermined height is formed.

The color filter substrate for the liquid crystal display device according to the present invention can be manufactured by the method as described above.

The spacer forming method may be applied to the lower substrate as well as the upper substrate of the liquid crystal panel as described above.

Hereinafter, a process of forming a spacer patterned on a lower substrate will be described with reference to FIG. 5.

5 is a cross-sectional view taken along the line VV of FIG. 1.

As shown, a conductive metal is deposited and patterned on the substrate 200 to form a gate electrode 202 and a gate wiring (not shown).

A gate insulating layer 204, which is a first insulating layer, is formed on an entire surface of the substrate 200 on which the gate wiring (not shown) and the gate electrode 202 are formed.

An island-like active layer 206 and an ohmic contact layer 208 are stacked on the gate insulating layer 204 on the gate electrode 202.

Next, a conductive metal is deposited and patterned on the entire surface of the substrate 200 on which the active layer 206 and the ohmic contact layer 208 are formed, thereby contacting the ohmic contact layer 208 with the source electrode 210 and the drain. An electrode 212 is formed.

In this case, the source electrode 210 intersects the gate wiring (not shown) and protrudes from the data wiring 214 defining the pixel region P.

One selected from the group of transparent organic insulating materials including benzocyclobutene (BCB) and acrylic resin (resin) on the front surface of the substrate 200 on which the data line 214 and the source and drain electrodes 210 and 212 are formed. Is applied to form a protective film 216 which is a second insulating film.

The passivation layer 216 is subsequently patterned to form a drain contact hole 218 exposing a portion of the drain electrode 212.

Next, the transparent pixel electrode 220 formed in the pixel region P is formed while contacting the exposed drain electrode 212.

The transparent pixel electrode 220 is formed of one selected from a group of transparent conductive metal materials including indium tin oxide (ITO) and indium zinc oxide (IZO).

Next, an alignment layer 222 is formed by coating a transparent resin such as polyimide (PI) on the entire surface of the substrate 200 on which the pixel electrode 220 is formed.

Subsequently, the spacer 224 having a predetermined shape is formed in the same manner as described above on the gate wiring (not shown) or the data wiring 214 in the same manner as described above.

In the array substrate, the gate line and the data line serve as a mask to block light.

As described above, a patterned spacer may be formed on a first substrate (upper substrate) or a second substrate (lower substrate) constituting the liquid crystal panel of the present invention.

Therefore, the manufacturing of the liquid crystal panel according to the present invention has the following effects.

First, in the process of forming the spacer, the material cost is reduced because the spacer forming material is coated only on the spacer forming region, not the method of coating the spacer forming material on the entire surface of the substrate.

Second, since the coated spacer film is patterned by a back exposure process, a separate mask process is not required.

Therefore, the mask process can be reduced, so that the yield of the product can be improved.

Claims (5)

In the method of forming a spacer for a liquid crystal display device formed on the first substrate or the second substrate to maintain the gap between the first substrate and the second substrate, Forming a spacer pattern film in an inkjet method only on any spacer forming region defined in the substrate; Irradiating light from a lower portion of the substrate on which the spacer pattern layer is formed; Developing the spacer pattern layer to form a spacer. Method for forming a spacer for a liquid crystal display device comprising. The method of claim 1, The spacer forming material is a positive photosensitive organic material spacer forming method for a liquid crystal display device. Forming a color filter comprising a black matrix and a subcolor on the substrate; Forming a transparent common electrode on the color filter; Forming an alignment layer on the common electrode; Forming a plurality of photosensitive organic layer patterns on the alignment layer on the black matrix by using inkjet; Irradiating light from a lower portion of the substrate on which the plurality of photosensitive organic layer patterns are formed; Developing a photosensitive organic film pattern irradiated with light to form a spacer on the black matrix; Color filter substrate manufacturing method for a liquid crystal display device comprising a. The method of claim 3, wherein The photosensitive organic layer pattern is a color filter substrate manufacturing method for a liquid crystal display device formed of a positive photosensitive material. Forming a plurality of gate wirings and data wirings crossing each other on the substrate to define pixel regions; Forming a thin film transistor including a gate electrode, an active layer, a source electrode, and a drain electrode in a region where the gate wiring and the data wiring cross each other; Forming a transparent pixel electrode in the pixel region while being in contact with the drain electrode of the thin film transistor; Forming an alignment layer on the entire surface of the substrate on which the pixel electrode is formed; Forming a plurality of organic layer patterns on the alignment layer on the gate line and the data line by using inkjet; Irradiating light from a lower portion of the substrate on which the plurality of photosensitive organic layer patterns are formed; Developing a photosensitive organic film pattern irradiated with light to form a spacer having a predetermined shape on the gate wiring and the data wiring; Array substrate forming method of the liquid crystal panel comprising a.