KR20050049657A - Method of fabricating color filter substrate using less mask - Google Patents

Abstract

The color filter substrate manufacturing method of the present invention is to simplify the manufacturing process by overlapping each sub-color pigment and forming a black matrix using a chemical reaction at the interface between the pigments. Providing a substrate divided into three subpixel regions and a black matrix region; And forming first, second, and third organic layers in the first, second, and third subpixel regions, respectively, using the first, second, and third subcolor pigments that are discolored by chemical reaction at the boundary surface, and in the black matrix region. Stacking the first, second, and third subcolor pigments to simultaneously form a black matrix and a color filter layer.

Description

Manufacturing method of color filter substrate with reduced number of masks {METHOD OF FABRICATING COLOR FILTER SUBSTRATE USING LESS MASK}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a color filter substrate, and more particularly, to a method of manufacturing a liquid crystal display panel color filter substrate having a reduced number of masks and an improved optical density of a black matrix.

In today's information society, display is more important as a visual information transmission medium, and in order to gain a major position in the future, it is necessary to satisfy requirements such as low power consumption, thinness, light weight, and high definition. Liquid Crystal Display (LCD), the flagship product of Flat Panel Display (FPD), has not only the ability to satisfy these conditions of the display but also mass production. It has been established as a core parts industry that can gradually replace the existing cathode ray tube (CRT).

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.

To this end, the liquid crystal display device includes a liquid crystal display panel including a driving circuit unit to output an image, a backlight unit installed under the liquid crystal display panel to emit light to the liquid crystal display panel, and the backlight. It consists of a case (case) for supporting the unit and the liquid crystal display panel combined.

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

1 is a plan view schematically illustrating a structure of a general liquid crystal display panel.

As shown in the figure, the liquid crystal display panel is largely a liquid crystal formed between a color filter substrate 5 and an array substrate 10 and between the color filter substrate 5 and the array substrate 10. It consists of a liquid crystal layer 50.

The color filter substrate 5 distinguishes between the color filter 7 including a sub color filter (red, green, blue) and the sub color filter to implement color, and blocks light transmitted through the liquid crystal layer 50. A black matrix 6 and a transparent common electrode 8 that applies a voltage to the liquid crystal layer 50.

In addition, the array substrate 10 includes a plurality of gate lines 16, data lines 17, and gate lines 16 arranged vertically and horizontally on the substrate 10 to define a plurality of pixel regions 19. A thin film transistor (TFT) 20, which is a switching element formed at an intersection region of the data line 17, and a pixel electrode 18 formed on the pixel region 19 are formed.

Although not shown in the drawings, an alignment layer for initial alignment of the liquid crystal 50 is provided on the common electrode 8 and the pixel electrode 18 formed on the color filter substrate 5 and the array substrate 10, respectively. It is formed in the front surface of the board | substrate 5,10. The alignment layer is mainly coated using a polyimide-based organic material, and then an initial orientation is determined through a rubbing process in which the alignment layer is rubbed with a cloth or the like.

The color filter substrate 5 and the array substrate 10 configured as described above are joined to face each other by sealants (not shown) formed on the outer side of the image display area to form a liquid crystal display panel. It is made through a bonding key (not shown) formed on the color filter substrate 5 or the array substrate 10.

Meanwhile, the structure of the color filter substrate will be described in detail as follows.

FIG. 2 is a cross-sectional view illustrating a structure of a color filter substrate of the liquid crystal display panel illustrated in FIG. 1.

As shown in the figure, the black matrix 6 is formed at regular intervals on the color filter substrate 5 made of a transparent insulating material such as glass. The black matrix 6 is made of an opaque metal material or resin that blocks unnecessary light from the light from the array substrate 10, which is a lower substrate of the liquid crystal display panel.

In this case, the black matrix 6 is arranged in a matrix form so as to correspond to the gate line 16 and the data line 17 arranged vertically and horizontally on the array substrate 10.

On the other hand, red (7a), green (7b), and blue (7c) for expressing an image in color in the pixel region 19 defined by the black matrix 6, that is, the black matrix 6 is not formed. Filled with colored resin).

At this time, a transparent overcoat layer 9 is formed on the color filter layers 7a to 7c made of the color resin to compensate for the steps of the color filters 7a to 7c and to prevent pigment ion elution. In addition, a common electrode 8 made of a transparent metal material for applying an electric field to the liquid crystal molecules 50 is formed on the passivation layer 9.

Next, a manufacturing process of the color filter substrate of the liquid crystal display panel configured as described above will be described in detail with reference to FIGS. 3A to 3C.

3A to 3C are flowcharts illustrating a manufacturing process of the color filter substrate illustrated in FIG. 2.

First, as shown in FIG. 3A, a black matrix 6 made of a resin or metal material for blocking unnecessary light is formed on a substrate 5 made of a transparent insulating material such as glass.

In general, the black matrix 6 is formed between red, green, and blue sub-color filters, and blocks light passing through a reverse tilt domain formed at the periphery of the pixel electrode 18 of the lower array substrate 10. It aims to do it.

In general, as the material of the black matrix 6, a metal film such as chromium (Cr) having an optical density of 3.5 or more is used, or an organic material such as carbon is mainly used, and for the purpose of low reflection A bilayer film such as chromium / chromium oxide (Cr / CrOx) may be used.

Thereafter, as shown in FIG. 3B, color filters 7a to 7c formed of sub color filters of red 7a, green 7b, and blue 7c are formed in the image display area between the black matrices 6. do.

In this case, there are various color filter manufacturing processes such as dyeing, electrodeposition, pigment dispersion, and printing. Here, as an example, a color filter manufacturing process by pigment dispersion is described.

First, any one of red, green, and blue color resins is applied to the entire surface of the substrate 5 on which the black matrix 6 is formed (described here based on application in the order of red, green, and blue). It exposes and forms the red sub color filter 7a in a desired area | region.

Next, a green color resin is applied onto a substrate on which the red subcolor filter 7a is formed, and the green subcolor filter 7b through selective exposure is patterned in a corresponding region.

In addition, the blue sub color filter 7c is formed by repeating the above process for blue.

When the sub-color filter layers of red (7a), green (7b), and blue (7c) formed when forming the color filter (7a to 7c) layer form a predetermined pattern, each sub-color filter (7a to 7c) ) Are formed in the same pattern, the respective sub-color filter (7a ~ 7c) layer can be formed by shifting the mask having a predetermined pattern by a predetermined distance to proceed the mask process.

Next, as shown in FIG. 3C, after forming the protective film 9 for preventing pigment ion elution on the entire surface of the substrate 5 including the color filters 7a to 7c, the liquid crystal molecules may be applied to the liquid crystal molecules. A common electrode 8 made of a transparent metal material is formed.

As described above, the manufacturing of the color filter substrate basically requires a mask process (that is, a photolithography process) to manufacture the black matrix and the color filter, and thus a method of simplifying the mask process in terms of productivity is required. . That is, since one mask process requires a series of complex processes such as deposition, exposure, development, and cleaning of the photoresist film, reducing one mask process contributes to the reduction in production volume and manufacturing cost of the liquid crystal display device.

In particular, the mask designed to form the pattern is very expensive, there is a problem that the manufacturing cost of the liquid crystal display device increases in proportion to the increase in the number of masks applied to the process.

SUMMARY OF THE INVENTION 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 color filter substrate by simplifying a process by reducing the number of masks used by overlapping each subcolor pigment to form a black matrix.

Another object of the present invention is to provide a method for manufacturing a color filter substrate having a black matrix having an improved optical density by forming a black matrix using a chemical reaction at the interface between the pigments.

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

In order to achieve the above object, the method of manufacturing a color filter substrate of the present invention comprises the steps of providing a substrate divided into first, second and third sub-pixel regions and black matrix regions composed of sub-color filters and chemical reaction at the boundary surface. First, second and third organic films are formed in the first, second and third subpixel regions by using the first, second and third sub-color pigments that are black, and the first, second and third subs are formed in the black matrix region. Stacking color pigments to simultaneously form a black matrix and a color filter layer.

In this case, simultaneously forming the black matrix and the color filter layer may include forming a first organic layer using a first sub-color pigment in the first subpixel region and the black matrix region of the substrate, and the second subpixel region of the substrate. And forming a second organic film with a second subcolor pigment in the black matrix region and forming a third organic film with a third subcolor pigment in the third subpixel region and the black matrix region of the substrate. .

In addition, the subcolor pigments may be composed of red, green or blue subcolor pigments.

In addition, the organic layer may be formed through a process of applying, exposing and developing a color resist photosensitive and photosensitive with a sub color pigment, and the color resist may be of a negative type.

On the other hand, the first, second, and third sub-color pigments laminated on the black matrix region may be blackly discolored by chemical reaction at the boundary surface to increase the optical density of the region.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the manufacturing method of the color filter substrate according to the present invention.

First, FIG. 4 is a cross-sectional view showing the structure of the color filter substrate of the present invention, and shows a color filter substrate in which the number of masks is reduced by overlapping each sub-color pigment to form a black matrix.

As shown in the figure, the sub-color filters 107a to 107c of red 107a, green 107b, and blue 107c colors are maintained on a substrate 105 made of a transparent insulating material such as glass. The black matrix 106 is formed between the sub color filters 107a to 107c by stacking red 107a, green 107b, and blue 107c sub color filters 107a to 107c. It is.

At this time, although not shown in the drawing, the substrate 105 has a protective film made of a transparent insulating material on the front surface of the substrate 105 to compensate for the step difference between the sub-color filters 107a to 107c and the black matrix 106 to prevent pigment ion elution. On the passivation layer, a common electrode for applying an electric field to the liquid crystal molecules and an alignment layer for initial alignment of the liquid crystal molecules are formed.

As such, the black matrix 106 is formed by stacking the sub-color pigments 107a to 107c without a separate process for manufacturing the black matrix 106 (that is, a series of processes including a mask process). There is an advantage that the manufacturing process of the filter substrate is simplified.

However, the higher the transmittance of the pigments 107a to 107c in the area of the color filters 107a to 107c composed of the subcolor pigments 107a to 107c, the higher the luminance of the display panel is. The subcolor pigments 107a to 107c are used. The higher the transmittance, the lower the contrast ratio and the sharpness of the panel.

That is, the color filters 107a to 107c and the black matrix 106 are required to have optically different characteristics, and when the black matrix 106 is formed of the sub-color pigments 107a to 107c as described above. Since the optical density of the black matrix 106 is not high enough to serve as the black matrix 106, light leakage occurs in the black mattress 106 region.

For reference, the optical density refers to the amount of light at a certain intensity after the light passes through the solution layer with a certain intensity and is also called absorbance. That is, if a light with an intensity I ₀ passes through the solution layer and then the luminous intensity becomes I, the amount is defined as log ₁₀ (I ₀ / I).

Light leakage of the black matrix region can be solved by using a chemical reaction between the sub-color pigments at the boundary surface of each sub-color filter constituting the black matrix. That is, when each sub-color filter is composed of sub-color pigments that are discolored by a chemical reaction, the black matrix area, that is, the boundary surface of each sub-color filter constituting the black matrix, becomes black to effectively prevent light leakage. do.

Accordingly, the manufacturing process of the color filter substrate of the present invention having the improved optical density of the black matrix will be described in detail with reference to FIGS. 5A to 5D.

First, as shown in FIG. 5A, a transparent insulating substrate divided into a subpixel region composed of red, green, and blue subcolor filters and a black matrix region that distinguishes between the subcolor filters and blocks light passing through the liquid crystal layer. Prepare (205).

Meanwhile, FIGS. 5B to 5D illustrate a manufacturing process of simultaneously forming a black matrix and a color filter using the pigment stack according to the present embodiment.

In general, a method of forming a color filter includes a dye method and a pigment method according to the material of the organic filter used to manufacture the color filter, and there are dyeing methods, electrodeposition methods, printing methods, etc., depending on the manufacturing method. The most common method used in the manufacture of color filters is pigment dispersion.

The said pigment dispersion method is a method of forming a color filter by repeating the process of apply | coating, exposing, and developing the resist which was prepared and photosensitive with the pigment prepared previously.

First, as shown in FIG. 5B, a photosensitive first organic layer 207a is formed on the substrate 205. The first organic layer 207a is composed of a sub-color pigment exposed to ultraviolet rays. In the present embodiment, the sub-color filter is formed of red, green, and blue color resists in the order of red, green, and blue. The color resist having the description) was applied to the entire surface of the substrate and then selectively exposed to form a red subcolor filter 207a in a desired region.

In this case, the red, green, and blue sub-color filters are formed by using a photolithography process, except that color resists are used as photoresists.

In general, the color resist has the characteristics of a negative photoresist so that the unexposed portions are removed. At this time, a positive photoresist from which the exposed portion is removed may be used.

Meanwhile, the color resist used in the pigment dispersion method is composed of photopolymerizable photosensitive compositions such as photopolymerization initiators, monomers, and binders and organic pigments that realize color as main components.

In the photopolymerization type photosensitive composition, the photopolymerization initiator is a generic term for three kinds of six-membered cyclic compounds represented by a molecular formula of C ₃ H ₃ N ₃ containing high-sensitivity and stable triazine (nitrogen triatoms) that generate radicals by receiving light. ) -Based compound is used, the monomer is changed to the polymer form by the radical after the start of the polymerization reaction is insoluble in the solvent. The binder serves to maintain the liquid monomer in the form of a film at room temperature to withstand the developer, stabilize the pigment dispersion, and maintain the reliability of heat resistance, light resistance, chemical resistance, etc. of the color filter pattern.

Pigments use organic materials with excellent light resistance and heat resistance. Pigment particles are generally opaque by scattering light, but when the particle size is smaller than the wavelength of light, the pigment is transparent by transmitting light. Indicates.

Next, as shown in FIG. 5C, a green color resist is coated on the entire surface of the substrate 205 on which the red subcolor filter 207a is formed, and then selectively exposed to expose the green subcolor filter 207b as the second organic layer. Form.

At this time, the green subcolor filter 207b is stacked on the red subcolor filter 207a formed in the black matrix 206 to serve as the black matrix 206, and in particular, the subcolor filters 207a and 207b. The red and green sub-color pigments constituting) are chemically reacted and discolored at the boundary surface to provide an effect of increasing the optical density of the black matrix 206.

Subsequently, as shown in FIG. 5D, a blue color resist is coated on the entire surface of the substrate 205 on which the red and green subcolor filters 207a and 207b are formed, and then selectively exposed to the blue subcolor filter 207c as a third photosensitive film. ), The color filter is completed.

At this time, the blue sub-color filter 207c is stacked on the red and green sub-color filters 207a and 207b that are already formed in the black matrix 206 region, and the green and blue sub-color filters 207b and 207c are stacked. The green and blue sub-color pigments constituting the chromium are also chemically reacted and discolored, thereby being able to sufficiently serve as the black matrix 206 to block unnecessary light.

That is, as shown in part A of the drawing, first, second and third organic films (i.e., sub-color filters) 207a to 207c are stacked in the region where the black matrix 206 is formed to form a triple layer. It can be seen that the interface between the first, second and third organic films 207a to 207c is discolored black by the chemical reaction between the pigments.

In particular, the optical density of the black matrix 206 can be improved by discoloration at the interface of the sub color filters 207a to 207c, and the black matrix 206 can be improved without depending on the transmittance of the subcolor filters 207a to 207c. The optical density of can be improved.

On the other hand, when the sub-color filter layers of red (207a), green (207b), and blue (207c) colors formed when the color filter (207a to 207c) layers are formed, each of the sub-color filters (207a) Since ˜207c are formed in the same pattern, each of the sub-color filter 207a to 207c layers may be formed by moving the mask on which a predetermined pattern is formed by a predetermined distance to perform a mask process.

Although not shown in the drawings, an indium tin oxide (ITO) or an indium zinc oxide (ITO) for forming an transparent protective film on the substrate 205 and then applying an electric field to the liquid crystal molecules on the protective film. A common electrode composed of a transparent electrode such as Indium Zinc Oxide (IZO) is formed.

At this time, the protective film is formed of a transparent resin having insulating properties to planarize the substrate 205 on which the color filters 207a to 207c are formed and to prevent the elution of the pigment ions. The protective film may be formed of an acrylic resin or an epoxy resin.

In addition, the common electrode is necessary in a twisted nematic (TN) mode in which an electric field is vertically applied between the color filter substrate and the array substrate, but the common electrode is formed on the array substrate together with the pixel electrode. This is not necessary in In Plane Switching (IPS) mode.

Meanwhile, an organic layer may be patterned on the common electrode or the protective layer to form a column spacer for maintaining a cell gap between the substrates.

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, the method for manufacturing a color filter substrate according to the present invention shortens a series of processes for forming the black matrix by forming a black matrix by laminating sub-color pigments when forming the color filter layer, and as a result, color. Simplifying the filter process provides the effect of increasing production.

In addition, the discoloration of the sub-color pigment at the sub-color filter interface can improve the optical density of the black matrix without depending on the transmittance of the sub-color filter.

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

FIG. 2 is a cross-sectional view illustrating a structure of a color filter substrate of the liquid crystal display panel illustrated in FIG. 1.

3A to 3C are flowcharts illustrating a manufacturing process of the color filter substrate illustrated in FIG. 2.

4 is a cross-sectional view showing the structure of a color filter substrate of the present invention.

5A to 5D are flowcharts illustrating a manufacturing process of a color filter substrate according to an exemplary embodiment of the present invention.

** Explanation of symbols for main parts of drawings **

105,205: color filter substrate 106,206: black matrix

107a ~ 107c, 207a ~ 207c: sub color filter

Claims (8)

Providing a substrate divided into first, second, and third subpixel regions and a black matrix region composed of subcolor filters; And First, second and third organic films are formed in the first, second and third subpixel regions by using first, second and third sub-color pigments which are discolored by a chemical reaction at the boundary surface, respectively. A method of manufacturing a color filter substrate comprising the step of laminating 1, 2, 3 sub-color pigments to simultaneously form a black matrix and a color filter layer. The method of claim 1, further comprising forming a protective film on the entire surface of the substrate. The method of claim 2, further comprising forming a common electrode on the passivation layer. The method of claim 1, wherein forming the black matrix and the color filter layer simultaneously Forming a first organic film with a first subcolor pigment in a first subpixel region and a black matrix region of the substrate; Forming a second organic film with a second subcolor pigment in the second subpixel region and the black matrix region of the substrate; And Forming a third organic film with a third sub-color pigment in the third subpixel region and the black matrix region of the substrate. The method of claim 1, wherein the subcolor pigment is composed of red, green, or blue subcolor pigments. The method of manufacturing a color filter substrate according to claim 1, wherein the organic film is formed through a process of applying, exposing and developing a color resist photosensitive and photosensitive with a sub-color pigment. 7. The method of claim 6, wherein the color resist is of a negative type. The method of claim 1, wherein the first, second, and third sub-color pigments laminated on the black matrix region are blackly discolored by chemical reaction at the boundary surface to increase the optical density of the black matrix region. Way.