KR100233072B1 - Method of manufacturing color filter - Google Patents

Abstract

Provided is a color filter in which the step difference between the overlapping portion of the light blocking layer and the color layer is minimized.

In the state where the color layer is blocked with a mask smaller than the distance between the adjacent black matrices, ultraviolet rays are exposed to the color layer in front of the color layer, and the color layer can be obtained to a desired thickness by exposing the periphery of the black matrix by diffuse reflection on the substrate surface.

The step difference between the overlapping portion of the light blocking layer and the color layer is minimized and does not require a separate planarization process.

Description

Color filter manufacturing method

The present invention relates to a method for manufacturing a color filter of a liquid crystal display device, and in particular, to minimize the step of the color layer to prevent the leakage of light, and to reduce the number of steps by not using the back exposure technique and the overcoat coating technique. The present invention relates to a method for manufacturing a color filter.

In general, a method of manufacturing a color filter widely used in a liquid crystal display device includes a dyeing method and a dispersion method, which is divided into a method of dyeing and dispersing a dye as a dye and a method of dispersing a pigment as a dye.

Among these, the dye dyeing method is a method of dyeing with a dyeing solution after exposing and developing the saltable and photosensitive resin on a transparent substrate, and the dye dispersion method is a method of etching a polyimide film in which a dye is dispersed using a photoresist. In addition, the pigment dispersion method is classified into a method of applying a photosensitive material in which a pigment is dispersed in a photosensitive resin, followed by exposure and development, and a method of etching a non-photosensitive material in which a pigment is dispersed in a polyimide by using a photoresist. Can be.

In such a conventional color filter manufacturing method, a back exposure technique and an overcoat coating technique have been used to minimize the step difference between the overlapping portion of the light blocking layer and the color layer.

Hereinafter, the manufacturing method of the color filter which concerns on a prior art is demonstrated with reference to drawings. Here, the same reference numerals have the same function.

1A to 1G show a method of manufacturing a color filter by a conventional back exposure technique.

First, as shown in FIG. 1A, color filter elements R, G, and B are formed on the transparent glass substrate 1 at regular intervals. Thereafter, as shown in FIG. 1B, the black resin 2 is applied over the entire substrate (may be laminated using a metal such as Cr). Subsequently, as shown in FIG. 1C, ultraviolet rays are exposed (backside exposure) from the lower side of the substrate to form a black matrix 4 that serves as a light blocking layer. At this time, since the light transmittance of the black resin 2 is remarkably low, it is very difficult to accurately match the thickness with the color filter elements R, G, and B. For that reason, sufficient exposure is required to form the black matrix 4 to a desired thickness, but even in this case, black resin may remain on the upper surface of the color filter element due to excessive exposure. Thus, as shown in Fig. 1D, after the back exposure is performed, front exposure is further performed using a mask 3 from the top of the color filter. In this case, the portion not exposed by the first back exposure is changed to the exposed portion by the front exposure added. In the same figure, the stripe part in the black resin 2 is the black resin part changed by the back exposure. As a result so far, as shown in Fig. 1E, a black matrix 4 which serves as a color filter element for realizing color and a light blocking film is formed on the substrate. Subsequently, indium tin oxide (ITO) and a transparent electrode material are applied to form a transparent conductive film 5, as shown in FIG. 1F, and then a color filter for a liquid crystal display device is applied by applying the protective film 6 as shown in FIG. 1G. Is completed.

However, according to the above method, since not only the back exposure but also the front exposure must be performed, there is a disadvantage that the process becomes complicated and the production cost increases.

2A to 2H show a method of eliminating the step difference between the overlapping portion between the light blocking layer and the color layer by the overcoat coating technique of the conventional dyeing method.

First, as shown in FIG. 2A, the black matrix 4 is formed on the glass substrate 1, and then, as shown in FIG. 2B, the soluble photosensitive film 7 is applied, and as shown in FIG. 2C, the mask 3 is used. Front exposure. In addition, as shown in Fig. 2D, the dye layer 8 pattern is formed, and as shown in Fig. 2E, the desired colors (R, G, B) are dyed and fixed. Subsequently, the process of FIGS. 2B to 2E is repeated to form the color filter elements R, G, and B on the substrate as shown in FIG. 2F. However, the color filter elements R, G, and B formed in this way are very difficult to maintain uniform thickness because each element is formed separately. Thus, as shown in Fig. 2G, the overcoat layer 9 is applied for the purpose of planarization, which also serves to protect the color filter layer. Finally, as shown in FIG. 2H, the color filter element is completed by forming a transparent conductive film 5 by applying a transparent electrode material such as ITO on the overcoat layer 9.

FIG. 3 is a diagram illustrating a method of removing a step between a light blocking layer and a color layer overlapping portion in a color filter by a general off focusing method. As shown in the same drawing, first, a black matrix for blocking light on the transparent substrate 1 is shown. After forming (4), a photosensitive film is applied thereon to form a color layer, and the step between the light blocking layer and the overlapped portion of the color layer is exposed by exposing ultraviolet rays using a mask 3 larger than the distance between adjacent black matrices. Remove S That is, the off-focusing method means that when manufacturing a color filter, the gap between the light blocking layer and the overlapping layer of the color layer is increased by increasing the gap between the substrate and the mask and reducing the exposure amount to reduce the exposure amount at the end of the mask. Say how to minimize it.

However, in such an off focusing method, since the color layer is directly exposed by a large amount of ultraviolet light, it is very difficult to accurately remove the stepped portion, and the step of overlapping the light-blocking layer and the overlapped portion of the color layer by applying the overcoat layer described above is also difficult. The removal method was very disadvantageous in terms of production cost because it additionally required a step of applying the overcoat layer.

In other words, the method of eliminating the step difference between the overlapping portion of the light blocking layer and the color layer by using the back exposure and the front exposure technique is expensive because of the complicated process, and similarly, the light blocking layer and the color layer using the overcoat technology. The method of eliminating the stepped portion of the overlapping portion of Hs also has disadvantageous manufacturing requirements for the above reasons.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the prior art, and the light blocking layer and the color are increased by increasing the distance between the substrate and the mask, making the size of the mask smaller than the distance between adjacent black matrices, and increasing the exposure dose. An object of the present invention is to provide a color filter for a liquid crystal display device in which the step difference of the overlapped portion of the layer is minimized.

Another object of the present invention is to provide a liquid crystal display device of high quality using a color filter in which the step difference between the overlapping portion of the light blocking layer and the color layer is minimized.

In order to achieve the above object, the present invention adopts a modified off focusing method to manufacture a color filter.

The present invention is a modification of the general off focusing method described above, and first forms a black matrix for light blocking by applying and patterning black resins such as casein, gelatin and acrylic on a transparent substrate (metals such as chromium or chromium oxide are formed). Can also be formed by lamination and patterning). Subsequently, a photosensitive film is applied over the entire substrate to form a color layer. Subsequently, ultraviolet rays are front-exposed into the color layer in a state in which the color layer is blocked with a mask having a size smaller than the distance between adjacent black matrices. Ultraviolet light transmitted through the color layer causes diffuse reflection at the substrate surface, whereby the exposure effect due to the first front exposure and the diffuse reflection effect are generated from the lower portion of the color layer (the contact surface between the color layer and the substrate). Since the exposure amount due to diffuse reflection is gradually increased, the color layer can be obtained by a desired thickness by appropriately adjusting the exposure time.

According to the present invention, it is possible to produce a color filter having a minimum step difference between the overlapping portion of the light blocking layer and the color layer by a simple process compared to the conventional technology, it is possible to implement a high-quality liquid crystal display device at a low production cost.

1A to 1G are views showing a conventional method for manufacturing a color filter.

2A to 2H show a method of eliminating the step difference between the overlapped portion of the light blocking layer and the color layer using a conventional over coat technique.

FIG. 3 is a diagram showing a method of eliminating the step difference between overlapping portions of the light blocking layer and the color layer by a general off-focusing method. FIG.

4A to 4D are views showing a method of eliminating the step difference between the overlapping portion between the light blocking layer and the color layer according to the preferred embodiment of the present invention.

-Explanation of symbols for the main parts of the drawing-

(1) ----------------------------------- PCB,

(2) ------------------------------- black resin,

(3) --------------------------------- mask,

(4) --------------------------- Black Matrix,

(5) ----------------------------- Transparent conductive film,

(6) --------------------------------- Shield,

(7) --------------------------------- photoresist,

(8) --------------------------------- dyed layer,

(9) ---------------------------- Overcoat layer.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Here, the same reference numerals in the prior art apply.

4A-4D illustrate a method of manufacturing a color filter in accordance with a modified off focusing method of the present invention.

First, as shown in FIG. 4A, black resin is applied (or stacked on a metal film) (not shown) on a substrate (upper or lower plate) and patterned to form a light blocking black matrix 4 at regular intervals. As shown in the figure, the photosensitive film 8 is applied to form a color layer (not shown). Subsequently, as shown in FIG. 4C, ultraviolet rays are exposed to the front face in a state in which the color layer is blocked using the mask 3, wherein the size of the mask 3 is between the adjacent black matrices as shown in the same drawing. Make it smaller than the interval. This increases the amount of exposure of ultraviolet light diffused from the substrate 1 over a long time in the region between the end of the mask 3 and the end of the black matrix 4 (conventionally; 200 to 300 mJ, the present invention; 600 to 900 mJ). This is for minimizing the level difference generated at the boundary between the color layer and the black matrix 4. Although there is no direct transmission of ultraviolet rays due to front exposure in the region, diffuse reflection of the ultraviolet rays reflected by the substrate exists, so that the level difference between the overlapping portion between the light blocking layer and the color layer is controlled by appropriately adjusting the exposure amount and the exposure time. Is minimized. As a result, the overlapping portion of the light blocking layer and the color layer exists in an extremely fine area, and even if overlapping, the step exists in an extremely fine size of about 2000 to 3000 mW. This is very effective in preventing the leakage of light due to rubbing for the purpose of later alignment of the liquid crystal. Through the above process, as shown in Fig. 4D, a color filter for a liquid crystal display device of high quality can be obtained in which the step difference between the color filter elements R, G, and B and the light blocking black matrix is minimized.

According to the modified off focusing method of the present invention, a color filter in which the step difference between the light blocking layer and the overlapping portion of the color layer is minimized can be minimized, and light leakage can be prevented during processing such as rubbing.

In addition, the present invention uses a modified off focusing method, and thus does not require an overcoat layer for planarization. That is, the production cost can be reduced due to the reduction in the number of processes.

As a result, a high quality liquid crystal display device is made possible by a color filter made through a simple process and composed of a light blocking layer and a color layer having a uniform thickness.

Claims (13)

Forming a plurality of light blocking layers that block light on the substrate; Forming a color layer on upper surfaces of the light blocking layers; And irradiating light onto a surface of a color layer of a region smaller than an interval between two adjacent light shielding layers of the plurality of light shielding layers to etch light. The method of manufacturing a color filter of a liquid crystal display device according to claim 1, wherein the light is irradiated from the front side of the substrate. The method of claim 1, wherein the light is ultraviolet light. The method of manufacturing a color filter of a liquid crystal display device according to claim 1, wherein a region between the portion exposed by light and the light shielding layer is exposed by diffuse reflection. The method of manufacturing a color filter of a liquid crystal display device according to claim 1, wherein the light shielding layer is made of a resin. The method of manufacturing a color filter of a liquid crystal display device according to claim 1, wherein the light shielding layer is made of metal. The color filter manufacturing method of claim 5, wherein the resin is a black resin. The method of manufacturing a color filter of a liquid crystal display device according to claim 6, wherein the metal is an opaque metal. The method of manufacturing a color filter of a liquid crystal display device according to claim 1, wherein the color layer is formed by dyeing a dye. The method of claim 1, wherein the color layer is formed by dispersing a dye. The method of claim 1, wherein the forming of the light blocking layer comprises applying a black resin and then patterning the black resin. The method of claim 1, wherein the forming of the light blocking layer comprises stacking an opaque metal and then patterning the light blocking layer. The method of claim 1, wherein the forming of the color layer comprises applying a photosensitive film and then patterning the color layer.

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