KR101050138B1 - Color filter and manufacturing method of color filter - Google Patents

Abstract

The present invention relates to a method for manufacturing a color filter and a color filter manufactured by the method, specifically, (a) forming a light shielding pattern on a substrate; (b) plasma-processing the substrate on which the light blocking portion pattern is formed; (c) coating a solvent on the substrate on which the light shielding pattern is formed; And (d) filling ink into the pixel portion partitioned by the light shielding portion pattern, and a color filter manufactured by the method.

Color filter, inkjet, plasma, solvent coating

Description

COLOR FILTERS AND METHOD OF MANUFACTURING COLOR FILTERS}

1 is a process of manufacturing a color filter using an inkjet method.

2 is a cross-sectional view illustrating a state in which ink is discharged after applying a solvent onto a substrate on which a light shielding portion pattern is formed.

3 is a photograph of a charge-coupled device (CCD) camera coated with a solvent by a spin coating method.

4 is a photograph of a CCD camera according to Embodiment 1 of the present invention.

5 is a photograph of a CCD camera according to Comparative Example 1 of the present invention.

6 is a photograph of a CCD camera according to Comparative Example 2 of the present invention.

Fig. 7A is a CCD camera photograph showing the diameter of the ink droplets inside the pixel portion after plasma treatment.

FIG. 7B is a CCD camera photograph showing the diameter of the ink droplets inside the pixel portion after coating the solvent on the plasma treated light shielding portion.

8 is a photograph of a CCD camera according to Comparative Example 3 of the present invention.

9 (a) is a photograph of a CCD camera according to Comparative Example 4 of the present invention.

FIG. 9B is a photograph of a CCD camera showing a state in which a solvent is coated only in a pixel portion after plasma treatment.

<Description of Major Symbols in Drawing>

1: Shading part 2: Substrate

3: solvent 4: red ink film

5: green ink film 6: blue ink film

The present invention relates to a method for producing a color filter and a color filter produced by the method. More specifically, in the method of manufacturing a color filter, after forming the light shielding part pattern, plasma treatment of the light shielding part pattern and coating a solvent having a low volatility to prepare an excellent color filter without unfilled color stains inside the pixel part during ink ejection A method and a color filter produced thereby.

In general, micropatterns used in display devices, such as semiconductor circuit devices and LCDs, are formed by photolithography using photoresist, and are generally manufactured through coating, exposure, development, cleaning, and curing. . However, although photolithography has the advantage of obtaining precisely the desired pattern, it has to go through many stages of processing, many kinds of materials are used to maximize the effect of photoresist, and in coating processes. The disadvantage is that a large amount of photoresist is consumed. Recently, in order to overcome such disadvantages of photolithography, a technique of obtaining a fine pattern by an inkjet printing method has been proposed.

In the manufacture of color filters by inkjet printing, a black matrix (BM) is formed by a conventional photolithography method, and R, G, and B are formed on the pixel portion between the light blocking part patterns using the light blocking part pattern as a partition wall. It is possible by spraying the ink of. A schematic diagram of a process of manufacturing a color filter using the inkjet printing method is shown in FIG. 1. At this time, if the light shielding part pattern used as the partition wall does not have ink repellency against the ink, the ink sprayed on the pixel part between the light shielding part patterns flows over the light shielding part pattern and flows into the adjacent pixel part, so that the mixed color of the same or different colors is generated. It may occur. Therefore, the light shielding material, which serves as a partition wall in inkjet printing, must have a large ink repellency for ink.

On the contrary, the substrate surface of the pixel portion must have low ink repellency only for ink, so that the ejected ink can be uniformly well spread in the pixel portion, and the light leakage phenomenon due to unfilling in the pixel portion can be eliminated and the step in the pixel portion or between pixels can be reduced. However, in general, when the light blocking part pattern is formed, a light blocking part component or a surfactant component having a low molecular weight flows into the surface of the glass substrate of the pixel portion partitioned by the light blocking part pattern during the post-baking process. As a result, during the plasma treatment for increasing the ink repellency of the light shielding portion, the surface of the pixel portion is also modified to have ink repellency by the plasma treatment. As a result, unfilling occurs because ink does not spread well inside the pixel portion even when jetting ink. As a result, the level difference between the pixel portion and the pixel portion is severely generated.

In order to solve such a problem, Japanese Patent Laid-Open No. 2004-00200557 forms a partition having liquid repellency, and applies a lyophilic liquid that expresses lyophilic on a substrate on which the partition is formed to form a lyophilic layer on the pixel portion, The method of apply | coating the ink droplet of a coloring agent to the pixel part in which the lyophilic layer was formed is proposed. At this time, the lyophilic layer component used is characterized in that it contains oxide fine particles such as titanium oxide (transparent at room temperature), zinc oxide, tin oxide, strontium titanate, tungsten oxide, bismuth oxide and iron oxide in water or alcohol. However, these oxides may not only be colored at room temperature, but may also be discolored during the post-treatment process such as post-baking of the ink film. The heat treatment process such as the post bake is performed at a high temperature of 200 ° C. or higher, which causes a problem that the color of the final color film is changed. In addition, in the case of using specific oxide fine particles, a manufacturing method is complicated, such as plasma treatment to express lyophilic, or an ultraviolet filter is installed so that a photocatalytic reaction does not occur.

Further, Japanese Laid-Open Patent Publication No. 2004-00200557 describes a configuration in which ink is ejected after a lyophilic material is introduced into a pixel and immediately evaporated to dry to form a film with a transparent layer. However, when the ink is discharged after drying the lyophilic material as described above, the diameter of the ink droplets increases in the pixel portion, but there is a problem that it is difficult to completely solve the ink dispersal.

In the present invention, by using a solvent contained in the ink as a lyophilic material, it does not change the color of the final color film, and the solvent is a material removed during the process, it has a feature that does not affect the color thickness. And by using the substance contained in ink, the problem of the dispersion stability being reduced can be prevented.

Accordingly, an object of the present invention is to improve the spreadability of ink in a pixel portion partitioned by the light shielding portion while maintaining the ink repellency of the light shielding portion serving as a partition wall in the method of manufacturing a color filter, thereby improving the spreadability of ink in the pixel portion or the pixel portion. The present invention provides a method for manufacturing a color filter having no mixed color of the inside, no color dropping due to unfilling, and having a uniform surface and a small step in the pixel portion or between the pixel portions, and a color filter manufactured by the method.

The present invention,

(a) forming a light shielding pattern on the substrate;

(b) plasma-processing the substrate on which the light blocking portion pattern is formed;

(c) coating a solvent on the substrate on which the light shielding pattern is formed; And

(d) filling ink into a pixel portion partitioned by the light blocking portion pattern

It provides a method of manufacturing a color filter comprising a.

The present invention provides a color filter manufactured by the above method and a liquid crystal display including the color filter.

Hereinafter, the present invention will be described in detail.

Method for manufacturing a color filter according to the present invention comprises the steps of (a) forming a light shielding pattern on the substrate; (b) plasma-processing the substrate on which the light blocking portion pattern is formed; (c) coating a solvent on the substrate on which the light shielding pattern is formed; And (d) filling ink into the pixel portion partitioned by the light blocking portion pattern.

The (a) forming the light shielding part pattern on the substrate may include: (a1) coating the light shielding part forming composition on the substrate; (a2) pre-baking the coated light shielding composition to form a light shielding film; (a3) selectively exposing, developing, and drying the light shielding film.

Although the material of the said board | substrate is not specifically limited, A glass substrate, a plastic substrate, another flexible substrate, etc. can be used, A transparent glass substrate with strong heat resistance is preferable.

In the step (a1), the method of coating the light shielding composition on the substrate may be performed by a method known in the art, for example, spin coating, slit coating, dip coating, or doctor blading.

The composition for forming a light shielding part may include a carbon black, an organic pigment mixed light shielding colorant, or a hybrid color material in which carbon black and an organic pigment mixed light shielding colorant are mixed as the light shielding color material, from 20 to 20 solids in the total solid content of the composition for light shielding part formation. It is preferable to contain 50 weight%.

In the step (a2), the prebaking is preferably performed at 80 to 120 ° C. for 1 to 5 minutes.

Selective exposure, development and drying in the step (a3) can be carried out using a method known in the art. The exposure is performed by using an exposure apparatus such as a mask aligner, a stepper or a scanner, and the g-ray (436 nm), h-ray (405 nm) or i-ray (365 nm) alone or mixed light source through the pattern mask on the light shielding film. It exposes. The exposure energy is determined according to the sensitivity of the light shielding film, and usually 20 to 200 mJ / cm ² can be used. After the exposure is completed, a desired light shielding part pattern can be formed by dipping or spraying the substrate with a developer. In addition, after the development is completed, the light shielding part pattern may be post-baked to enhance adhesion to the lower substrate. It is preferable to perform the said post-baking conditions for 10 to 200 minutes at 200-250 degreeC.

It is preferable that the thickness of the light shielding part pattern manufactured in step (a) is 1.1 to 5 μm, and the optical density (OD) is 2 to 6 in the thickness range.

In the step (b), plasma treatment is performed on the substrate on which the light blocking part pattern is formed.

The substrate on which the light shielding portion pattern is formed is subjected to a plasma treatment under conditions using CF ₄ gas to perform hydrophobization surface treatment. Before plasma treatment under the condition using CF ₄ gas, some components introduced from the light blocking part to the inner surface of the pixel part may be removed by plasma treatment under the condition using O ₂ gas. In general, a plasma is generated by increasing a voltage between two electrodes having different potential differences in a vacuum state, and may be applied to areas such as surface cleaning, surface modification, surface etching, or surface deposition depending on the type of gas used for plasma formation. Can be. In the present invention, the light shielding portion pattern may be hydrophobized by CF ₄ as an active gas through plasma surface etching and surface deposition of a hydrophobic layer so that the light shielding portion pattern may have ink repellency. This makes it possible to coat the solvent only on the pixel portion without the solvent discharged during the subsequent solvent coating remaining on the light shielding pattern. The light shielding part pattern may preferably have a contact angle of 20 ° or more with respect to the ink after the plasma treatment. When the contact angle is less than 20 °, the solvent may not be selectively coated only inside the pixel portion.

The diameter of the ink droplet inside the pixel portion after the plasma treatment is shown in Fig. 7A .

Step (c) is a step of coating a solvent on the substrate on which the light blocking part pattern is formed.

The solvent to be coated on the substrate on which the light blocking part pattern is formed is preferably a solvent constituting the ink composition jetted to the pixel part, but has good compatibility with a binder without impairing the dispersibility of the pigment in the ink. A solvent with a low boiling point of 150 degreeC or more can be used. Specific examples of the solvent include butyl carbitol acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, methoxy ethanol, ethoxy ethanol, butoxy ethanol, ethoxy ethyl acetate, butoxy ethyl acetate, and the like. It may be used, but is not limited thereto, and preferably butyl carbitol acetate may be used. The solvent may be used alone, but may include 0.1 to 3 parts by weight of a silicone-based surfactant or a fluorine-based surfactant based on 100 parts by weight of the coating solvent in order to control the spreadability in the pixel portion.

As a method of coating the solvent, spin coating, slit coating, dip coating, spray coating, flow coating, or the like may be used, but is not limited thereto. Among the coating methods, spin coating is preferred, which is easy to process and can be processed within a short period of time. 3 is a photograph of a solvent coated by a spin coating method.

When the solvent is coated on the entire surface of the substrate on which the light shielding part pattern is formed by the coating method, since the light shielding part pattern has ink repellency by plasma treatment, the solvent may be coated only inside the pixel part. The coated solvent is preferably coated with a solvent component up to the tapered portion of the light blocking portion as shown in FIG. 2 (b). However, the solvent may be coated only on the glass inside the pixel as shown in FIG. 2 (b ').

The solvent may be filled in an amount required by the inkjet method in order to fill an accurate amount inside the pixel portion during the ink coating. Since the viscosity of the ink used in the inkjet has a value of 5 to 60 cP at room temperature, the fluidity is not large in the pixel portion. Thus, unfilled ink may be generated at the corners of the pixel portion region. However, in general, since the viscosity of the solvent constituting the color ink by the inkjet method is less than 5 cP, when the solvent is filled by the inkjet method, the ejected ink may be uniformly filled in the pixel portion.

In the step (d), the ink is filled in the pixel portion partitioned by the light blocking portion pattern, and two or more kinds of inks, for example, three kinds of inks, such as R, G, and B, may be simultaneously or continuously filled. The ink may use a photocurable or thermosetting ink. The ink filling is preferably performed by an inkjet method. In addition, the ink is preferably discharged in a state in which the solvent is coated inside the pixel portion and is not dried. When the ink is ejected while the solvent is dried, the diameter of the ejected ink droplets tends to increase, but it is difficult to completely solve the dispersion of the ink inside the pixel portion. The diameter of the ink droplet inside the pixel portion after coating the solvent on the plasma treated light shielding portion is shown in Fig . 7B .

FIG. 2 (c) shows a picture after curing by discharging ink into a pixel portion filled with a solvent. The solvent used as the lyophilic liquid is a material constituting the ink or a solvent which does not inhibit the dispersibility of the pigment in the ink and is compatible with the binder so that the solvent cannot be separated.

When each ink is discharged to the pixel portion by the inkjet method, the light-shielding portion pattern formed according to the method of the present invention has ink repellency and the pixel portion has an ink repellency, so that the ejected ink spreads uniformly in the pixel portion. It may be applied higher and convex than the light shielding pattern.

Since the ink discharged in this process does not cross the ink-blocking shading pattern, three ink can be continuously discharged without a separate post-treatment process for each ink. Photocuring or thermosetting may be performed.

In the case of the photocurable ink, pre-bake is performed for 10 to 2000 seconds after each ink discharge or after all ink discharges at a temperature of 50 to 150 ° C., and exposure is performed at an exposure dose of 40 to 300 mJ / cm ² . After the high temperature thermal curing may be carried out for 10 to 200 minutes at a temperature of 200 to 250 ℃. In the case of thermosetting ink, after pre-bake for 10 to 2000 seconds at 50 to 150 ° C. after each ink discharge or after all the ink is discharged, the temperature is 200 to 250 ° C. without a separate exposure process. High temperature thermosetting can be carried out for 10 to 200 minutes.

The present invention provides a color filter manufactured by the above method.

The color filter manufactured as described above maintains the inking properties of the pixel portion without the process of forming a separate inking layer and without complicated surface treatment, so that no color mixture, color dropout, unfilled, uneven color and uniform surface are filled during ink filling. Can be manufactured and the cost can be reduced by simplifying the process.

The present invention provides a liquid crystal display device including the color filter.

The liquid crystal display according to the present invention may have a configuration known in the art except for including the color filter according to the present invention described above.

Example  One

The light shielding part-forming composition was spin-coated on a glass substrate and prebaked at about 100 ° C. for 2 minutes. Then, after cooling at room temperature, it was exposed with an energy of 100 mJ / cm 2 under a high pressure mercury lamp using a photomask. The exposed substrate was developed by spraying with 0.04% aqueous KOH solution at a temperature of 25 ° C., washed with pure water, dried by air blowing, and post-baked in a convection oven at 220 ° C. for 30 minutes. -bake) to form a light shielding part pattern having a thickness of about 2.4 μm. Thereafter, hydrophobized surface treatment by plasma was performed under CF ₄ gas conditions. The size of the pixel portion partitioned by the formed light shielding portion pattern was 200 μm × 600 μm.

The butyl carbitol acetate used as the solvent in the ink composition of the present invention was spin coated at 1000 rpm for 10 seconds to coat the light-shielding pattern. Before the coated solvent was dried, 10 drops, 20 drops, 30 drops, and 40 drops of ink were discharged into the solvent-filled pixel. The results are shown in FIGS. 4 (a) to 4 (d), respectively.

Comparative example  One

A light shielding part pattern was formed in the same manner as in Example 1, except that the solvent was coated.

10 drops, 20 drops, 30 drops, and 40 drops of ink were discharged into the formed pixel portion. The results are shown in Figs. 5 (a) to 5 (d), respectively.

Comparative example  2

A light shielding portion pattern was formed in the same manner as in Example 1. The butyl carbitol acetate used as the solvent in the ink composition of the present invention was coated on a substrate on which the light shielding pattern was formed by spin coating at 1000 rpm for 10 seconds, and then dried in air.

Into the solvent-filled pixel, 30 drops and 40 drops of ink were discharged. The results are shown in FIGS. 6 (a) to 6 (b), respectively.

Comparative example  3

A light shielding portion pattern was formed in the same manner as in Example 1 except that the hydrophobized surface treatment by plasma was not performed. Thereafter, 20 drops of ink were discharged to the pixel portion without filling the solvent. The results are shown in FIG. 8. As can be seen in FIG. 8, it can be seen that the light-shielding portion pattern does not have ink repellency, so that ink flows through the light-shielding portion pattern.

Comparative example  4

A light shielding portion pattern was formed in the same manner as in Example 1 except that the hydrophobized surface treatment by plasma was not performed. The butyl carbitol acetate used as the solvent in the ink composition of the present invention was spin coated at 1000 rpm for 10 seconds to coat the light-shielding pattern. As shown in FIG. 9 (a), when the plasma surface treatment is not performed, the light shielding portion is not hydrophobized, and thus the solvent is coated on the entire substrate, thereby preventing ink jetting. On the contrary, FIG. 9B shows a state in which the light shielding portion is hydrophobized after the plasma surface treatment, and the solvent is filled only in the pixel portion to enable ink jetting.

In the present invention, in manufacturing a color filter, while maintaining the ink repellency of the light shielding portion pattern serving as a partition wall, while maintaining the hydrophilicity of the pixel portion between the light shielding portion pattern to improve the spreading of the ink in the pixel portion between the pixel portion or between pixel portions It is possible to manufacture a color filter that does not have mixed color, no color dropping due to unfilling, and the surface is uniform and the level difference between the pixel portion and the pixel portion is small.

Claims (16)

(a) forming a light shielding pattern on the substrate; (b) plasma-processing the substrate on which the light blocking portion pattern is formed; (c) coating a solvent on the substrate on which the light shielding pattern is formed; And (d) filling ink into a pixel portion partitioned by the light blocking portion pattern Including; The solvent in the step (c) is a manufacturing method of the color filter, characterized in that the solvent constituting the ink composition. The method of claim 1, wherein the forming of the light blocking part pattern comprises: (a1) coating a light shielding part composition on a substrate; (a2) pre-baking the coated light shielding composition to form a light shielding film; (a3) A method of manufacturing a color filter comprising the step of selectively exposing, developing and drying the light shielding film. The composition for forming a light shielding portion according to claim 2, wherein the composition for forming a light shielding portion comprises a hybrid color material obtained by mixing carbon black, an organic pigment mixed light shielding colorant, carbon black and an organic pigment mixed light shielding colorant as a light shielding color material. Method for producing a color filter, characterized in that it comprises 20 to 50% by weight of the total solids. The method of claim 1, wherein the thickness of the light blocking portion pattern in the step (a) is 1.1 to 5 ㎛. The method according to claim 1, wherein the optical density of the light shielding pattern in the step (a) is 2 to 6, characterized in that the manufacturing method of the color filter. The method of manufacturing a color filter according to claim 1, wherein the light blocking pattern after the plasma treatment in the step (b) has a contact angle of 20 ° or more with respect to the ink. The method according to claim 1, wherein the plasma treatment in step (b) is CF ₄ Method for producing a color filter is carried out under the conditions using a gas. The method according to claim 1, wherein the solvent in the step (c) comprises a 0.1 to 3 parts by weight of the silicone-based surfactant or fluorine-based surfactant based on 100 parts by weight of the coating solvent. delete The method of claim 1, wherein the solvent in the step (c) is butyl carbitol acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, methoxy ethanol, ethoxy ethanol, butoxy ethanol, ethoxy ethyl Method for producing a color filter, characterized in that any one selected from the group consisting of acetate and butoxy ethyl acetate. The method of claim 1, wherein the ejecting of the ink in the step (c) is performed in a state in which the solvent is not dried. The method of claim 1, wherein the step (d) is to fill two or more kinds of inks simultaneously or continuously. The method of claim 1, wherein the ink filling in the step (d) is performed by an inkjet method. The method according to claim 1, wherein the ink in the step (d) is a photocurable or thermosetting ink. The color filter manufactured by the manufacturing method of any one of Claims 1-8 and 10-14. A liquid crystal display device comprising the color filter of claim 15.

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