KR20100086884A - Color filter and method for manufacturing the same - Google Patents

Abstract

PURPOSE: A color filter and a method for manufacturing the same are provided to prevent a color stain phenomenon and a light leakage phenomenon by standardizing the dry speed of inks on the center part and on the edge part. CONSTITUTION: A light-shielding layer pattern is formed on a substrate. Inks are filled in a pixel unit which is divided by the light-shielding layer pattern. The amount of inks filled in the edge part(b, b') of a color filter is less than that of inks filled in the center part(a) of the color filter. A soft-baking process is performed with respect to the filled inks. Inks are additionally filled in the pixel unit which is located on the edge part of the color filter. A post-baking process is performed with respect to the additionally filled inks.

Description

COLOR FILTER AND METHOD FOR MANUFACTURING THE SAME}

The present invention relates to a method for manufacturing a color filter having a uniform film thickness, a color filter manufactured by the same, and a display device including the same.

In general, a liquid crystal display (LCD) displays an image by controlling light transmittance of a liquid crystal using an electric field. To this end, the LCD includes a liquid crystal panel in which liquid crystal cells are arranged in a matrix, and a driving circuit for driving the liquid crystal panel. The liquid crystal panel includes pixel electrodes for applying an electric field to each of the liquid crystal cells and a reference electrode, that is, a common electrode. The pixel electrode is formed for each liquid crystal cell on the lower substrate, while the common electrode is integrally formed on the front surface of the upper substrate. Each of the pixel electrodes is connected to a thin film transistor (hereinafter referred to as TFT) used as a switching element. The pixel electrode drives the liquid crystal cell together with the common electrode according to the data signal supplied through the TFT. Such LCDs can be miniaturized compared to CRTs, and are widely used in personal computers and notebook computers, as well as office automation devices such as photocopiers, portable devices such as cell phones and pagers.

In the liquid crystal display device, in order to display a color image, light generated from a light source is separated into three primary colors of light, that is, red, green, and blue light. To this end, a red (hereinafter referred to as 'R') filter that transmits only red light, a green (hereinafter referred to as 'G') filter that transmits only green light, and a blue (hereinafter referred to as 'B') filter that transmits only blue light are used for each pixel. I need it. R, G, and B filters should be formed so as not to overlap each other to prevent image deterioration and color bleeding. As a method of manufacturing a color filter of the liquid crystal display, a dye method, a pigment dispersion method, an electrodeposition method, a printing method, and the like are generally used. Among them, the dyeing method or the pigment dispersion method has the advantage of forming a fine pattern, while the photolithography process for each of the R, G, B inks are complicated, so the manufacturing process is complicated and material waste is disadvantageous. The electrodeposition method also has a disadvantage in that the manufacturing process is complicated because the electrodeposition and fixing processes for the inks of the three primary colors (R, G, B) are repeated. The printing method has a problem that it is difficult to uniformly control the thickness of the color filter. In order to overcome the drawbacks of these conventional color filter manufacturing methods, an inkjet type color filter manufacturing method capable of easily producing fine patterns in a relatively simple process has been actively studied. In the inkjet color filter manufacturing method, a color filter is formed by forming a grid-shaped partition wall for forming a cell region on a transparent substrate and then spraying ink into the cell region.

According to the inkjet printing method, since the material is discharged where necessary, there is no material consumption and the process can be simplified by a direct injection method without a mask. The process of manufacturing a color filter by inkjet technology first uses a conventional photolithography process to manufacture a black matrix (BM) of a resin component, which is a light shielding film, and as a partition, R, G, and B ink on the pixel portion between the BMs. Can be applied by ink jet.

 However, the thickness jet between the pixels at the edges of the substrate and the pixels at the center portion mainly occurs during the manufacture of the color filter by the inkjet printing method. Such nonuniformity of the color filter thickness has a problem that color spots are generated between pixels at the edge of the substrate and pixels at the center of the substrate. In addition, this thickness nonuniformity is known to be caused by the difference in the drying speed of the ink at the edge portion and the central portion of the substrate.

1 is a schematic view of a color filter manufactured by a conventional inkjet printing method, and as shown in FIG. 1, the central portion a of the color filter and the edges b and b 'of the color filter have non-uniform film thicknesses. Have

SUMMARY OF THE INVENTION In view of the problems of the prior art as described above, an object of the present invention is to provide a method of manufacturing a color filter having a uniform film thickness, a color filter manufactured thereby, and a display device including the same.

In order to achieve the above object, the present invention comprises the steps of (a) forming a light shielding film pattern on the substrate; (b) filling ink in the pixel portion partitioned by the light shielding film pattern, wherein the pixel portion partitioned at the edge of the color filter fills a smaller amount of ink than the amount of ink filled in the center of the color filter; Step: (c) soft baking the filled ink; (d) additionally filling ink into the pixel portion defined by the edge portion of the color filter; And (e) post-baking the filled ink.

The present invention also provides a color filter manufactured by the method for manufacturing the color filter.

In addition, the present invention provides a display device including the color filter.

The color filter manufactured according to the method of manufacturing a color filter according to the present invention has a uniform film thickness, and the display device including the same can prevent color spots and improve light leakage.

Hereinafter, the present invention will be described in more detail.

The present invention

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

(b) filling ink in the pixel portion partitioned by the light shielding film pattern, wherein the pixel portion partitioned at the edge of the color filter fills a smaller amount of ink than the amount of ink filled in the center of the color filter; step;

(c) soft baking the filled ink;

(d) additionally filling ink into the pixel portion defined by the edge portion of the color filter; And

(e) post-baking the filled ink

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

Step (a) is a process of forming a light shielding film pattern on a substrate. The step (a) may include: applying the light shielding film material on the substrate (a1); (a2) soft baking the light shielding film material; And (a3) selectively exposing and developing the soft baked light shielding film material.

A glass substrate, a plastic substrate, or a flexible substrate may be used as the substrate, but a transparent glass substrate having high heat resistance is preferable.

The method of applying the light shielding film material on the substrate in the step (a1) may be performed by a method known in the art, such as spin coating, dip coating or doctor blading.

The light-shielding film material may be used without limitation to those known in the art, but it is preferable to have ink repellency, and the light-shielding film material is formed of a light-shielding ink-based silicone or fluorine-based surfactant to have ink repellency. It is preferable to contain 0.01-0.3 weight part with respect to 100 weight part of total compositions for.

As the light-shielding coloring material of the light-shielding film material, a hybrid color material in which carbon black, an organic pigment mixed light-shielding colorant, carbon black and an organic pigment mixed light-shielding colorant is mixed, based on 100 parts by weight of 100 parts by weight of the total solid content of the light-shielding film-forming composition. It is preferable to contain 50 weight part. In addition, the binder polymer component preferably contains 20 to 50 parts by weight and a crosslinking agent of 20 to 40 parts by weight based on 100 parts by weight of the total solids.

The light shielding film-forming composition may include a solvent for coating properties. It is preferable to contain 60-90 weight part of said solvents with respect to 100 weight part of compositions for light shielding film formation.

In the step (a2), the soft bake is preferably performed at 50 to 150 ° C. for 10 to 1000 seconds.

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, through the pattern mask, a single or mixed light source of g-line (436 nm), h-line (405 nm) or i-line (365 nm) through the pattern mask. 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 film pattern can be formed by dipping or spraying the substrate with a developer. In addition, after completion of development, the light shielding film 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.

In the step (b), the ink is filled in the pixel portion partitioned by the light shielding film pattern, and the pixel portion partitioned at the edge of the color filter is less ink than the amount of ink filled in the center of the color filter. Filling step.

The edge portion of the color filter means an area of 0.1 to 5 mm in the central direction from the outermost part of the entire area of the color filter substrate, preferably 0.1 to 2 mm, more preferably 1 to 3 pixels.

The central portion of the color filter means all regions except the edge portion.

Specifically, the pixel portion partitioned at the center of the color filter is filled with ink to satisfy the color specification, and the pixel portion partitioned at the edge of the color filter is filled with 40 to 70% of the amount of ink filled at the center. It is desirable to. If the amount of ink filled in the pixel portion partitioned at the edge of the color filter is less than 40%, the amount of ink is insufficient, and the ink cannot spread evenly within the pixel portion, and if it exceeds 70%, The additional discharge does not show any improvement in the film thickness variation.

The filling of the ink may simultaneously or successively fill two or more kinds of inks, such as three inks of R, G, and B. The ink may use a photocurable or thermosetting ink. The ink filling is preferably performed by an inkjet method. The amount of ink filled can be fluid, depending on the LCD application model.

Step (c) is a step of soft baking the filled ink. The soft baking step may remove some of the solvent component of the filled ink, and may be subjected to low temperature heat treatment.

The soft bake is preferably performed at 50 to 150 ° C. for 10 to 2000 seconds.

In the step (d), ink is additionally filled in the pixel section partitioned at the edge of the color filter.

The amount of ink additionally filled in the pixel portion partitioned at the edge of the color filter corresponds to the difference between the amount of ink filled in the pixel portion at the center and the edge of the color filter in step (b).

Specifically, the amount of ink additionally discharged to the edge of the color filter is preferably 30 to 60% of the total amount of ink discharged to the center of the color filter. If the amount of the additionally discharged ink is outside the above range, the desired color specification may not be satisfied.

The step (e) is a step of the post-baked discharged.

The post bake is preferably performed at 200 ° C. or higher and 200 to 250 ° C. for 10 to 60 minutes. It can also be cured in less than 10 minutes using an IR oven.

When the ink is a UV curable ink, a post bake process may be performed after UV exposure.

The UV irradiation is preferably performed for 1 to 20 seconds at an intensity of 10 to 100 kW / cm 2. More preferably, it is performed for 1 to 5 seconds at an intensity of 20 to 50 mW / cm 2.

In addition, the UV irradiation may be performed on the substrate surface or the surface on which the light shielding film pattern is formed.

In addition, the soft baking process of step (c) may be further performed to remove a part of the solvent component of the ink additionally discharged to the edge portion before the step (e).

The film thickness change according to each step in the manufacturing method of the color filter of the present invention is shown in FIG.

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

The color filter manufactured according to the method of manufacturing a color filter according to the present invention has a uniform film thickness, and the display device including the same can prevent color spots and improve light leakage.

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

The display device 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.

Hereinafter, the present invention will be described in detail by the following examples and comparative examples. However, the following examples are merely illustrative of the present invention, and the content of the present invention is not limited to the following examples.

Example

The light-shielding part forming composition was spin-coated on a glass substrate and subjected to heat treatment 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 a 0.04% KOH aqueous solution at a temperature of 25 ° C., washed with pure water, dried by air blowing, and post-baked for 30 minutes in a convection oven at 220 ° C. -bake) to form a light blocking film pattern having a thickness of about 1.8 μm.

Thereafter, the thermosetting ink was prepared, and two pixels from the edge of the color filter to the center part ejected 8 drops, and then 15 drops were emitted to the center part. After discharging by varying the amount of ink at the center and the edge of the color filter, soft baking was performed at 90 ° C. for 5 minutes. Thereafter, 7 drops of ink were further ejected to the edge portion. After the soft bake was performed at 90 ° C. for 5 minutes to partially remove the solvent component of the ink discharged to the edge of the color filter, the discharged ink was post-baked at 220 ° C. for 30 minutes to prepare a color filter.

The shape of the edge of the manufactured color filter was measured and shown in FIG. 3. As can be seen in Figure 3, it can be seen that the film thickness variation does not occur in the edge portion of the color filter manufactured according to the first embodiment.

Comparative Example 1

A light shielding film pattern was manufactured in the same manner as in Example 1.

Thereafter, 15 drops of thermosetting ink were discharged to all the pixel portions partitioned by the light blocking film pattern, and then soft baking was performed at 90 ° C. for 5 minutes. The discharged ink was post-baked at 220 ° C. for 30 minutes to prepare a color filter.

The shape of the edge portion of the manufactured color filter was measured and shown in FIG. 4. As can be seen in Figure 4, it can be seen that the film thickness variation occurs in the edge portion of the color filter manufactured according to Comparative Example 1.

Comparative Example 2

A light shielding film pattern was manufactured in the same manner as in Example 1.

Thereafter, the thermosetting ink was prepared, and two pixels from the color filter edge portion to the center portion discharged 5 drops, and thereafter, 15 drops were discharged to the center portion. After discharging by varying the amount of ink at the center and the edge of the color filter, soft baking was performed at 90 ° C. for 5 minutes. Thereafter, 10 drops of ink were further ejected to the edge portion. After soft baking was performed at 90 ° C. for 5 minutes to partially remove the solvent component of the ink discharged to the edge of the color filter, the discharged ink was post-baked at 220 ° C. for 30 minutes to prepare a color filter.

Fig. 5 is a photograph immediately after discharging five drops of ink to two pixels from the edge portion to the center portion of the color filter. As can be seen in FIG. 5, it can be seen that a problem occurs that ink is not evenly filled in the pixel portion of the edge of the color filter.

Comparative Example 3

A light shielding film pattern was manufactured in the same manner as in Example 1.

Thereafter, the thermosetting ink was prepared, and two pixels from the color filter edge portion to the center portion discharged 11 drops, and thereafter, 15 drops were discharged to the center portion. After discharging by varying the amount of ink at the center and the edge of the color filter, soft baking was performed at 90 ° C. for 5 minutes. Thereafter, 4 drops of ink were further ejected to the edge portion. After soft baking was performed at 90 ° C. for 5 minutes to partially remove the solvent component of the ink discharged to the edge of the color filter, the discharged ink was post-baked at 220 ° C. for 30 minutes to prepare a color filter.

The shape of the edge portion of the manufactured color filter was measured and shown in FIG. 6. As can be seen in Figure 6, it can be seen that the film thickness variation in the edge portion of the color filter manufactured according to Comparative Example 3 is not improved.

1 is a schematic diagram of a cross-sectional view of a color filter exhibiting a non-uniform film thickness manufactured according to the prior art.

2 is a schematic view showing the shape of the ink shown in accordance with the manufacturing method of the color filter of the present invention.

3 is a photograph showing the shape of the edge portion of the color filter according to the first embodiment of the present invention.

Figure 4 is a photograph showing the shape of the edge portion of the color filter according to Comparative Example 1 of the present invention.

5 is a photograph showing the shape of the edge portion of the color filter according to Comparative Example 2 of the present invention.

Figure 6 is a photograph showing the shape of the edge portion of the color filter according to Comparative Example 3 of the present invention.

<Brief Description of Drawings>

(a) Center of color filter

Edges of (b) and (b ') color filters

Claims (15)

(a) forming a light shielding film pattern on the substrate; (b) filling ink in the pixel portion partitioned by the light shielding film pattern, wherein the pixel portion partitioned at the edge of the color filter fills a smaller amount of ink than the amount of ink filled in the center of the color filter; step; (c) soft baking the filled ink; (d) additionally filling ink into the pixel portion defined by the edge portion of the color filter; And (e) post-baking the filled ink Method of manufacturing a color filter comprising a. The method according to claim 1, wherein step (a), (a1) applying a light shielding film material onto the substrate; (a2) soft baking the light shielding film material; And (a3) selectively exposing and developing the soft baked light shielding film material Method for producing a color filter comprising a. The method of claim 1, wherein the substrate is a glass substrate, a plastic substrate, or a flexible substrate. The method of claim 2, wherein the light blocking film material is ink repellent. The method of claim 2, wherein the light-shielding film material is 0.01 to 0.3 parts by weight of the silicone-based or fluorine-based surfactant based on 100 parts by weight of the total composition for forming the light-shielding film, 20 to 50 parts by weight of the coloring material, binder polymer relative to 100 parts by weight of the total solids of the composition 20 to 50 parts by weight, and 20 to 40 parts by weight of the crosslinking agent. The method of manufacturing a color filter according to claim 5, wherein the coloring material is a hybrid of carbon black, an organic pigment mixed light-shielding colorant, carbon black and an organic pigment mixed light-shielding colorant. The method of claim 1, wherein the edge portion of the color filter is a region of 0.1 to 5 mm from the outermost portion of the total area of the color filter toward the center portion. The color filter of claim 1, wherein the amount of ink filled in the pixel portion partitioned at the edge of the color filter is filled in an amount of 40 to 70% with respect to the amount of ink filled in the pixel portion partitioned at the center of the color filter. Manufacturing method. The method of claim 1, wherein the filling of the ink comprises filling two or more kinds of inks simultaneously or continuously. The method of claim 1, wherein the soft bake of step c) is heat treated at 50 to 150 ° C. for 10 to 2000 seconds. The method of claim 1, wherein the amount of ink additionally filled in the pixel portion partitioned at the edge portion of the color filter of step d) corresponds to the difference between the amount of ink filled in the pixel portion at the center portion and the edge portion of the color filter. Process for producing phosphor color filter. The method of claim 1, wherein the post-baking step of step e) is thermally cured at 200 to 250 ° C. for 10 to 60 minutes. The method of claim 1, wherein the soft bake process is further performed before the post bake step of step e). The color filter manufactured by the method of any one of Claims 1-13. A display device comprising the color filter of claim 14.

Images