KR100469390B1 - Color filter manufacturing method for lcd - Google Patents

Abstract

The present invention relates to a method of manufacturing a color filter of a liquid crystal display device. In the conventional method of manufacturing a liquid crystal display device, when the inkjet printing method is used, neighboring color layers are mixed, yield is lowered, and process reliability is lowered. There was this. In view of the above problems, the present invention includes the steps of applying a resin on the upper portion of the glass substrate; Patterning the resin by a photolithography process to form a black matrix having a rounded top surface by adjusting an exposure amount of the photolithography process or an etching time of the resin; When the color layer is formed by the inkjet printing method by manufacturing a color filter through a manufacturing process comprising the step of printing a color layer representing red, green, and blue on the glass substrate exposed between the black matrix, respectively, It is possible to prevent bleeding, to increase the stability and yield of the process, and to form a more uniform color layer by forming a slanted side of the black matrix, thereby improving light transmittance and color purity. There is.

Description

Color filter manufacturing method of liquid crystal display device {COLOR FILTER MANUFACTURING METHOD FOR LCD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a color filter of a liquid crystal display, and in particular, to change the structure of the black matrix of the color filter so as to prevent color mixing between neighboring color layers when forming the color layer of the color filter. A method of manufacturing a color filter of an apparatus.

In general, a liquid crystal display device displays a screen by diffracting light of a backlight using a liquid crystal driven according to a voltage difference between upper and lower electrodes, so that light is transmitted or blocked through upper and lower polarizing plates.

The above-described structure cannot display colors, and is provided with a color filter for filtering red, green, and blue light at positions opposite to each pixel in a lattice structure on the upper side for displaying colors. Implemented the color of.

The black matrix of the liquid crystal display is positioned at each boundary of the color filter color layer representing red, green, and blue, respectively, and serves to improve contrast of the entire liquid crystal display by blocking light in an area not controlled by the pixel electrode. Will be

Conventional methods used to produce the color filter including the black matrix use a method of depositing and patterning chromium or chromium oxide or applying and patterning a resin.

The method of forming the black matrix using the chromium or chromium oxide has a relatively low height of the black matrix, which is applied when forming the color layer by the pigment dispersion method.

In addition, the method of forming a black matrix using the resin may form a black matrix having a relatively high height, which is applied when forming a color layer by an inkjet printing method.

As mentioned above, the pigment dispersion method and the inkjet method are mainly used to form the color layer located between the black matrices. Such a conventional color filter and its manufacturing method will be described in detail with reference to the accompanying drawings. Same as

FIG. 1 is a conceptual view illustrating an operation of a general liquid crystal display. As shown in FIG. 1, a gate voltage is applied to a gate electrode 3 of a transistor, and an operating voltage applied through a data line is applied to the pixel electrode 4. The directionality of the liquid crystal 6 is changed by the voltage difference with the transparent electrode on the upper plate side, and the light transmittance of the backlight 27 is determined for each pixel.

Accordingly, the color of the light transmitted is expressed by the color filter 10.

In the color filter 10, a color layer 12 representing red, green, and blue colors is disposed between the black matrices 11 having a lattice structure.

Hereinafter, a method of manufacturing the conventional color filter 10 having the above structure will be described in more detail.

A method widely used as a conventional method for forming a color filter is a pigment dispersion method, which will be described in detail with reference to the accompanying drawings of a conventional color filter manufacturing method by the pigment dispersion method.

FIG. 2A to FIG. 2E are cross-sectional views of a process for manufacturing a conventional color filter using the pigment dispersion method, as shown in the steps of depositing chromium (Cr) on the glass substrate 21 (FIG. 2A); Coating and developing photoresist (PR) on top of the chromium (Cr) to form a pattern that exposes a portion of the deposited chromium (Cr) at uniform intervals (FIG. 2B); The chromium (Cr) is etched by the etching process using the photoresist (PR) pattern as an etch mask, and the photoresist (PR) pattern is removed to form the black matrix 22 on the glass substrate 21. Step (FIG. 2C); Sequentially forming color layers 23, R, G, and B having different colors between the black matrices 22 using a pigment dispersion method (FIG. 2D); The transparent electrode 24 is deposited on the upper surface of the color layer 23 (FIG. 2E).

Figure 3 is a flow chart of a conventional color filter manufacturing process using the pigment dispersion method.

Such a pigment dispersion method has a large amount of material consumption compared to other methods, but is most often used because of excellent thickness uniformity.

However, the photoresist coating, exposure, development, and post-baking processes must be performed for each of the three colors of R, G, and B, thereby making the manufacturing process complicated.

In addition, since the process of applying the photoresist by spin coating and the removal of most of the photoresist applied in the developing process, the manufacturing cost of the color filter is increased due to an expensive process with a large material loss. do.

In addition, since the liquid crystal display device has a large area, it is not easy to secure the uniformity of the photoresist applied by spin coating, and thus it is not applicable to manufacturing a large area color filter.

The inkjet printing method, which is a color layer forming method different from the pigment dispersion method, forms a relatively thick black matrix 22 using a resin, and is formed of a color layer component and an organic binder between the black matrix 22. The ink layer is pressurized, sprayed from a nozzle, dried, and the organic binder is removed to attach the color layer 23 to the glass substrate 21.

Such an inkjet printing method can reduce the production cost of the color filter since the amount of material used is smaller than other methods.

4A to 4E are cross-sectional views of a conventional color filter manufacturing process for forming the color layer 23 by the inkjet printing method. As shown in FIG. 4A to 4E, a resin is coated on the glass substrate 21 and a pattern is applied. Forming a resin black matrix 22 having a height higher than that of the chromium black matrix (FIG. 4A); Spraying the ink liquid R having a specific color by the inkjet method between the resin black matrices 22 (Fig. 4B); Drying the ejected ink liquid R to form color layers 23 and R (FIG. 4C); Spraying an ink liquid G having a different color from the color layers 23 and R between the black matrices 22 positioned on the side of the formed color layers 23 and R (Fig. 4D); And drying the ejected ink liquid G to form the color layers 23 and G (FIG. 4E).

However, the method of forming a color filter using the conventional inkjet printing method as described above requires printing a color layer 23 thicker than the black matrix 22 in order to obtain a color layer 23 having a desired thickness. As a result, the sprayed ink liquid may spread to other color layer areas before drying, thereby causing a decrease in yield.

In addition, the solvent contained in the ink liquid may penetrate the resin black matrix 22 to lose the repulsive force of the black matrix with respect to the ink liquid, which may cause a very difficult problem of forming a desired pattern.

In the process of forming the color layers 23 and R shown in FIG. 4C, the solvent contained in the ink solution can penetrate into the resin black matrix 22, thereby repulsing the black matrix 22 against the ink solution. Loss

In this state, when the ink liquid G of another color of FIG. 4D is jetted, the ink liquid G jetted through the black matrix 22 whose repulsive force is lost is exceeded, and when it is dried, the color layer 23 is dried. By mixing, the desired color filter cannot be obtained.

As described above, the manufacturing method of the color filter of the conventional liquid crystal display increases the manufacturing cost when the pigment dispersion method is used, and there is a problem that cannot be applied because a uniform pattern cannot be obtained in a large area.

In the case of using the inkjet printing method, the black matrix of the resin component is formed, and in the process of forming the color layer of the first color between the black matrix, the resin black matrix of the side of the color layer of the first color is formed. The component is changed and can spread to the upper side of the color layer of the first color before the color layer of the second color is dried in the process of forming the color layer of the second color in the adjacent area of the color layer of the first color. Thereby, there was a problem that the yield is lowered, thereby reducing the reliability of the process.

In view of the above problems, the present invention provides a method of manufacturing a color filter of a liquid crystal display device which can prevent color mixing of color layer patterns while forming a color layer by inkjet printing by forming a black matrix having a rounded top surface. There is a purpose.

1 is a conceptual view of the operation of a general liquid crystal display.

2A to 2E are cross-sectional views of a manufacturing process of a color filter using a conventional pigment dispersion method.

3 is a manufacturing process flowchart of the color filter to which the pigment dispersion method is applied.

4A to 4E are cross-sectional views of a color filter manufacturing process using a conventional inkjet printing method.

5A to 5E are cross-sectional views of a color filter manufacturing process using the inkjet printing method of the present invention.

6 is a configuration diagram of an ink jet head used in the ink jet printing method.

7A to 7C are schematic cross-sectional views showing the overflow of ink according to the conventional black matrix shape.

8A to 8C are schematic cross-sectional views showing the overflow of ink according to the black matrix shape of the present invention.

Figure 9 is a schematic diagram showing the force of gravity and the direction of progress of the conventional ink.

Figure 10 is a schematic diagram showing the force of gravity and the traveling direction of the ink of the present invention.

Figure 11 is a detailed view showing a cross section of a conventional color layer.

Figure 12 is a detailed view showing a cross section of the color layer of the present invention.

* Description of the symbols for the main parts of the drawings *

21: glass substrate 22: black matrix

23: Color layer

The above object is the step of applying a resin on top of the glass substrate; Patterning the resin by a photolithography process to form a black matrix having a rounded top surface by adjusting an exposure amount of the photolithography process or an etching time of the resin; It is achieved by manufacturing a color filter through a manufacturing process comprising the steps of printing a color layer showing red, green, and blue color on the glass substrate exposed between the black matrix, the accompanying drawings of the present invention Detailed description with reference to the following.

5A through 5E are cross-sectional views of a manufacturing process of a color filter of a liquid crystal display according to an embodiment of the present invention. As shown in FIG. 5A to 5E, resin is deposited on the glass substrate 21 and patterned by a wet etching process using a photoresist as a mask. Forming a resin black matrix 22 having a rounded top surface (FIG. 5A); Spraying an ink liquid of a specific color R on the glass substrate 21 exposed between the resin black matrices 22 by an inkjet printing method (Fig. 5B); Drying the ink liquid to form a color layer (23, R) of the specific color (R) (Fig. 5C); Spraying the ink liquid of a color (G) different from the color of the color layer (23, R) on the glass substrate 21 exposed adjacent to one side of the region where the color layer (32, R) is formed Step (Fig. 5D); Drying the ink solution G to form the color layers 23 and G (FIG. 5E).

Hereinafter, a method of manufacturing a color filter of the liquid crystal display of the present invention as described above will be described in more detail.

First, as shown in FIG. 5A, a resin is applied to the entire upper surface of the glass substrate 21.

Next, a photoresist (not shown) is coated on the deposited resin, and exposed and developed to form a plurality of patterns positioned at predetermined areas on the upper portion of the resin so as to be spaced apart from each other by a predetermined distance.

Next, a resin black matrix 22, which is a resin pattern positioned in a lattice structure, is formed on the glass substrate 21 by an etching process using the photoresist pattern as an etching mask.

At this time, the upper surface of the resin black matrix 22 is rounded by adjusting the exposure amount or the time for etching the resin.

An exposure process using a semi-transmissive mask in the photoresist for controlling the exposure amount allows a relatively small amount of exposure to be performed on the photoresist corresponding to the upper portion of the side surface of the resin black matrix 22, thereby patterning the resin. At the time, the upper side of the resin black matrix 22 can be etched.

Unlike the pattern formation by controlling the exposure amount, when patterning the resin, the patterning time is longer so that the upper side surface portion of the resin black matrix 22 is etched, so that the resin black matrix 22 having a rounded top surface is etched. Can be obtained.

When the top surface of the resin black matrix 22 is rounded in this manner, the volume ratio of the color layer region defined by the resin black matrix 22 increases as compared with when the top of the resin black matrix is formed in parallel.

Then, as shown in Fig. 5B, the red (R) ink liquid is printed in the pixel region defined by the resin black matrix 22 by the inkjet printing method.

At this time, the red (R) ink liquid to be applied is not easily overflowed as the volume ratio of the pixel region defined by the resin black matrix 22 becomes larger than in the prior art.

Fig. 6 is a configuration diagram of the inkjet head for printing the ink liquid, and as shown therein, a piezoelectric body 61 which expands and contracts with application of voltage; An ink chamber 62 for storing ink; A diaphragm (DIAPHRAGM) 63 for applying pressure from the piezoelectric element 61 to the ink chamber 62 and an outer side of the ink chamber 62 and having a funnel-shaped structure, and the diaphragm 63 And a nozzle 64 for ejecting the ink in the ink chamber 62 to the outside by driving.

Such an inkjet head is provided with pixels of three colors in one unit by the number of pixels, which is related to the size of the liquid crystal display.

Then, as shown in FIG. 5C, the ink liquid of red R is dried to form color layers 23 and R representing red R. As shown in FIG.

Next, as shown in FIG. 5D, green (G) ink is printed on the glass substrate 21 adjacent to the color layers 23 and R of the red (R) color.

At this time, the green G ink also does not overflow to the upper side of the red color layers 23 and R as the volume ratio increases.

Then, as shown in FIG. 5E, the green G ink is dried to form green color layers 23 and G. As shown in FIG.

Hereinafter, the reduction of the ink overflow phenomenon according to the black matrix shape of the present invention as described above will be described in more detail in comparison with the shape of the conventional black matrix.

First, FIGS. 7A to 7C are schematic diagrams illustrating a process of applying ink and overflowing ink, and a black matrix 22 having a flat top surface is positioned on the glass substrate 21 as shown in FIG. Ink R is applied to the pixel region defined by (22).

As shown in FIG. 7A, when the ink R is located on the upper side of the black matrix 22, that is, in the area A, overflow of the ink to other pixel areas does not occur.

However, as shown in Fig. 7B, the force acts in the direction of the joint of gravity and the advancing direction of the ink while exceeding the region A, thereby spreading the ink R easily along the upper surface of the black matrix 22, which is a horizontal plane. Will occur.

As the above spreads, the ink R overflows to neighboring pixel regions as shown in Fig. 7C.

However, in the present invention, as shown in Figs. 8A to 8C, the occurrence of overflow occurs past the B region, which is the center portion of the resin black matrix 22, rather than the A region, which is the side portion of the black matrix 22.

9 and 10 are schematic diagrams showing the force according to the ink moving direction and the direction of gravity. As shown in the drawing, when the upper surface of the conventional resin black matrix 22 is flat, the ink moving direction C is shown. And the direction of gravity (G) are perpendicular to each other, so that the force is 45 degrees, the magnitude of the force is also relatively large.

However, as in the present invention, the joint force of the resin black matrix 22 is greater than 90 degrees between the advancing direction (C) and the gravity (G) of the ink, so that the joint force is relatively small compared to the prior art. As a result, the ink R may be prevented from overflowing to the other neighboring pixel area beyond the black matrix 22.

11 and 12 are cross-sectional views showing the shapes of the color layers of the conventional color filter and the color filter of the present invention, respectively. As shown in the drawing, the shape of the black matrix 22 is parallel to the top surface of the conventional color filter. In one case, since the side surface portion of the black matrix 22 is perpendicular to the glass substrate 21, the thickness of the color layer formed on the side surface portion of the black matrix 22 is relatively thick.

On the contrary, in the present invention, the angle formed between the side surface of the black matrix 22 and the upper surface of the glass substrate 21 is not perpendicular, so that the thickness of the color layer 23 formed on the side of the black matrix 22 is It becomes relatively thin, making the distribution of color layers more uniform.

By improving the uniformity of the color layer 23 as described above, the light transmittance is further improved, and the color purity can be improved by not generating the color difference.

As described above, the present invention has the effect of increasing the stability and yield of the process by forming the upper part of the black matrix round, preventing the bleeding of the ink when forming the color layer by the inkjet printing method.

In addition, by forming the side of the black matrix in a gentle inclined shape it is possible to form a more uniform color layer has the effect of improving the light transmittance and color purity.

Claims (4)

delete delete Applying a resin on top of the glass substrate; Patterning the resin by a photolithography process to form a black matrix having a rounded top surface by adjusting an exposure amount of the photolithography process or an etching time of the resin; And printing a color layer representing red, green, and blue on the glass substrate exposed between the black matrices, respectively. delete