JPH08297206A - Production of color filter - Google Patents

Abstract

PURPOSE: To improve the alignment accuracy by making the coating area for a liquid coating agent used for the pattern of the second and succeeding colors smaller than the area including the effective screen for the first color pattern and the alignment marks formed out of the effective screen. CONSTITUTION: Plural numbers of pigment-dispersion photoresists such as black, red, green and blue pigments are applied by a micro-rod resist coating method on a flat and transparent substrate such as a glass substrate 7, and then stripe patterns of plural colors such as black, red, green and blue colors are successively formed by a photolithographic method to obtain a color filter. In this method, the coating area 14 for pigment-dispersion photoresists 13 of the second and succeeding colors is made smaller than the area 12 including a black stripe pattern 10 as the first color and an alignment mark 11 which is formed out of the effective screen and formed at the same time when the black stripe pattern 10 is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a color filter, and more particularly to a method of manufacturing a color filter by applying a liquid coating agent on a transparent glass substrate and manufacturing the color filter by a lithographic method.

[0002]

2. Description of the Related Art A liquid crystal image display device for displaying an image using liquid crystal as an electrochemical material has a thinner structure than an image display device using a cathode ray tube, and is therefore a wristwatch, a calculator or a portable personal computer. Widely used as a display device. Further, recently, it has come to be used also as a display device for a color image.

A liquid crystal image display device that displays a color image uses a color filter for color selection. Hereinafter, a liquid crystal image display device that displays a color image will be described with reference to the drawings. There are various types of liquid crystal image display devices such as TFT and STN. For example, a plasma addressed liquid crystal display device that drives liquid crystal by using discharge plasma will be described as an example.

As shown in FIG. 6, the plasma addressed liquid crystal display device includes a first substrate 3 which is flat and optically transparent enough.
1 and a flat and transparent second substrate 32 similar to the first substrate 31, a liquid crystal layer 33 which is an electro-optical material layer is interposed, and the liquid crystal layer 33 and the second substrate 32 are provided. The space between and becomes the discharge region 34.

Between the first substrate 31 and the liquid crystal layer 33,
An electrode layer 35 including a band-shaped transparent electrode and a dummy electrode is formed. Here, the dummy electrode has the same thickness as the transparent electrode in order to keep the thickness of the liquid crystal layer 33 constant. Further, a color filter 36 for color selection is formed between the electrode layer 35 and the liquid crystal layer 33. The liquid crystal layer 33 is made of nematic liquid crystal or the like, and is sandwiched between a thin dielectric film 37 made of glass, mica, plastic, or the like and the color filter 36. The first substrate 31, the liquid crystal layer 33, Electrode layer 35, color filter 36 and dielectric film 3
A liquid crystal panel is composed of 7.

A discharge electrode group 38 is formed on the second substrate 32 as a strip electrode. Second substrate 32 and dielectric film 3
The space between 7 is the discharge region 34 for generating discharge plasma, as described above. The discharge region 34 is partitioned by a partition wall 39 formed by a printing method, and is formed as independent plasma chambers P ₁ , P ₂ , P ₃ ... P _n . Each of the plasma chambers P ₁ , P ₂ , P ₃ ... P _n is filled with an ionizable gas such as helium, neon, argon or a mixed gas thereof. Further, the liquid crystal layer 33 is sealed with the liquid crystal layer 33 side of the color filter 36 by a sealant applied to the dielectric film 37.

Here, the color filter 36 includes red (R), green (G), and blue (B) colored layers 36a, 36b,
36c are arranged in a mosaic pattern or a stripe pattern corresponding to the pixels, and each of the colored layers 36a, 36b,
36 c is partitioned by a block mask 36 d formed so as to overlap the partition wall 39. The black mask 36d prevents a decrease in contrast and color purity due to light blocking and leakage light between pixels.

In the plasma addressed liquid crystal display device thus constructed, the liquid crystal layer 33 functions as a sampling capacitor for the analog voltage applied to the transparent electrode formed on the first substrate 31, and in the discharge region 34. The generated discharge plasma functions as a sampling switch. Then, the colored layers 36a, 3 of the color filter 36
The color images color-selected by 6b and 36c are displayed.

There are several methods for forming the color filter 36, such as a photolithography method, a printing method, an electrodeposition method, and a transfer method. In a liquid crystal display for displaying a color image, the color filter is used. 36
The photolithography method is mainly used because high processing accuracy is required.

In this photolithography method, for example, a pigment-dispersed resist in which a pigment is dispersed in a photosensitive resin is applied to a glass substrate, a photomask having a pattern is opened, and then exposed, and then black, red, green, This is a method of sequentially forming blue stripe type color filters. The production of the color filter by the photolithography method will be described with reference to FIG. In order to form the color filter, first, as shown in FIG. 7A, a black mask 36d is formed in a predetermined mask pattern on, for example, the glass substrate 31 to be the first substrate 31. . Then, after the black mask 36d is formed,
As shown in FIG. 7B, a pigment-dispersed resist in which red, green, or blue pigment particles are dispersed is applied to a photosensitive resin to form a colored resist layer (first, a red resist layer 40). .) 40 is formed. The pigment-dispersed resist used in this color filter is a major factor in determining the characteristics of the panel and is required to have excellent transparency, heat resistance, and adhesion. For example, acrylic resin,
A polyimide resin is used.

Next, on the red resist layer 40, as shown in FIG.
As shown in (C) of polyvinyl alcohol (PV
The oxygen barrier film 43 is formed by applying A) or the like. Then, as shown in FIG. 7D, a photomask 44 having an opening corresponding to the formation pattern of the red resist layer 40 is covered and exposed on the oxygen blocking film 43. As a result, the red resist layer 40 is hardened except the unnecessary portion. Then, as shown in FIG. 7E, the oxygen barrier layer 4
By removing 3 and developing, a red layer 36a having a predetermined pattern is formed on the glass substrate 31.

By performing these steps in the same manner for the patterns of other colors, the colored layers 36a, 36 of R, G, B as shown in FIG.
The color filter 36 having b and 36c is formed.

By the way, in order to apply the colored resist layers 36d, 36a, 36b and 36c including the black pigment-dispersed photoresist for forming the black mask 36d to the glass substrate 31, conventionally, the thickness of the resist layer is changed. It was difficult to make the resist constant and apply the required amount of the resist.

For example, to form the black mask 36d shown in FIG. 7A, first, on the glass substrate 31,
The spin coating method was used to apply the black pigment resist uniformly with a thickness of 1 to 2 μm.

The process of forming the black mask 36d using this spin coating method will be described below. First, as shown in step S1 of FIG. 8, for example, a black pigment-dispersed photoresist is applied to the glass substrate 31 in a predetermined range with a film thickness of 1 to 2 μm by using a spin coater method.

Next, as shown in step S2, the glass substrate 31 coated with the black pigment dispersion photoresist is applied to the glass substrate 31.
Prebaking is performed at 5 to 110 ° C. for about 2 to 5 minutes to evaporate the solvent.

Next, as shown in step S3, exposure is performed through a photomask having the above-mentioned predetermined pattern.
That is, a photomask having an opening corresponding to the stripe pattern of the black mask 36d is prepared. At this time, the photomask is formed with openings corresponding to the stripe patterns and openings corresponding to the alignment marks necessary for alignment when forming the stripe patterns of the second and subsequent colors.

Next, as shown in step S4, the glass substrate 7 after exposure is immersed in an alkaline solution having a concentration of 1% for 60 seconds.
Dip while shaking to develop, then wash with water (rinse).

Next, as shown in step S5, the rinsed glass substrate 7 is heated at 200 to 230 ° C. for about 5 to 3 times.
Post bake for 0 minutes.

Then, a black mask and an alignment mark are formed on the glass substrate. Next, in order to form a red stripe pattern, the processing from step S1 to step S5 is repeated using the red pigment dispersion photoresist. Similarly, when forming the green and blue stripe patterns, the processes from step S1 to step S5 are repeated using the pigment-dispersed photoresist of each color. Finally, an overcoat film is formed to protect the stripe pattern of each color and to flatten the surface.

Here, when forming the stripe patterns of the second and subsequent colors, in the processing of step S4,
The alignment of the substrate with respect to each photomask is performed using the alignment mark. That is, in order to adjust the position of the photomask for the second color with respect to the pattern made for the first color, the alignment using the alignment mark is performed.

[0022]

By the way, in the spin coater method, the pigment-dispersed photoresist is coated on an unnecessary portion because the coating range of the pigment-dispersed photoresist is expanded by rotation, for example. This will cover the alignment mark produced when the stripe pattern of the black mask of the color is formed.

Normally, in the case of manual alignment, an alignment mark is projected on a monitor with a CCD (charge coupled device) camera, for example, and alignment is performed. At this time, if a pigment-dispersed photoresist of another color is applied in addition to the alignment mark, the image of the projected alignment mark has a very poor contrast. As a result, the image becomes difficult to see, and the alignment accuracy also deteriorates.

Further, in the case of automatic alignment, the alignment mark is binarized by image processing to determine the shape, but if the contrast is not sufficiently obtained, the shape may not be sufficiently determined. . Then, the alignment becomes impossible or the alignment accuracy is affected.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of manufacturing a color filter capable of improving alignment accuracy.

[0026]

A method of manufacturing a color filter according to the present invention comprises a step of applying a liquid coating material of a predetermined color onto a glass substrate and then repeating the process of forming a pattern of the predetermined color for a plurality of colors. When a color filter is manufactured by forming a pattern for a plurality of colors, a pattern for the second and subsequent colors is formed rather than an area including an alignment mark formed outside the effective screen of the pattern for the first color of the plurality of colors. The application area of the liquid coating agent used for is reduced.

[0027]

When the first color pattern of the plurality of colors is formed, the liquid coating agent used for pattern formation of the second and subsequent colors is more than the area including the alignment mark formed outside the effective screen of the stripe pattern. The application area can be reduced.

[0028]

EXAMPLES Examples of the color filter manufacturing method according to the present invention will be described below.

This embodiment is a method of manufacturing a color filter used for color selection in a liquid crystal image display device displaying a color image. According to this method of manufacturing a color filter, a black transparent substrate such as a glass substrate 7 is coated on a flat transparent substrate by a so-called microrod resist coating method.
Apply multiple pigment-dispersed photoresists such as red, green, and blue, and use photolithography method to print black, red, green,
A color filter is manufactured by sequentially forming stripe patterns of a plurality of colors such as blue. At this time, as shown in FIG. 1, the black stripe pattern 10 for the first color is formed outside the effective screen at the same time. Application area 1 of the pigment-dispersed photoresist 13 used for pattern formation of the second and subsequent colors, rather than the area 12 including the alignment mark 11.
Decrease 4.

The pigment-dispersed photoresist is a kind of color filter agent. The pigment-dispersed photoresist is a photoresist in which a pigment is dispersed. The pigment may be either an organic pigment or an inorganic pigment. As the organic pigment, for example, dianthraquinone is used as a red pigment, halogenated copper phthalocyanine is used as a green pigment, and copper phthalocyanine is used as a blue pigment. Other color filter agents include pigment dispersion resin, acrylic resin, polyimide resin, and the like.

In the micro rod bar resist coating method, the plurality of pigment-dispersed resists are coated on a transparent and flat glass substrate through recesses formed between stainless fine wires densely wound around a core rod. This method is applied to the microrod bar resist coating apparatus 9 shown in FIGS. The microrod bar resist coating device 9 is, for example, a rod 1 having a diameter of 12 mm shown in FIG.
For example, as shown in FIG. 3, a part of the microrod bar 3 on which the stainless thin wire 2 having a diameter of about 100 μm is closely wound is immersed in a resist liquid tank 4 in which the pigment-dispersed photoresist 6 is stored and rotated, The pigment-dispersed photoresist 6 is held in the recesses 5 between the stainless thin wires 2 and applied onto the filter forming surface 7 a of the glass substrate 7 conveyed onto the microrod bar 3. The glass substrate 7 is a roller 8
Is pressed by the micro rod bar 3 and is conveyed in the direction of arrow L by the rotation of the roller 8. After that, the transported glass substrate 7 has the filter forming surface 7a side facing upward, and the pigment dispersion resist 6 is flattened.

The microrod bar resist coating device 9 can coat the glass substrate 7 with a required amount of the pigment-dispersed resist, which facilitates liquid saving. This is because the pigment dispersion photoresist coating area 14 can be selected as shown in FIG. 5 depending on the winding range of the stainless thin wire 2 wound around the rod 1. In addition, the pigment dispersion photoresist 6
Since the thickness when applied, that is, the film thickness is determined by the diameter of the stainless thin wire 2 and the solid content concentration of the resist,
Uniform and easy to control.

Therefore, according to the method of manufacturing the color filter of this embodiment, when the color filter is manufactured, the pigment dispersion photo of the color to be formed next is formed on the alignment mark 11 formed of, for example, the black pigment dispersion resist. The pigment dispersion photoresist coating area 14 can be selected so that the resist 13 is not overcoated. Therefore, the alignment mark 11 remains in a state of being formed only in black on the transparent glass substrate 7, the contrast is improved, and it is easy to recognize even when performing image processing.
Therefore, the alignment accuracy can be improved.

That is, according to the method of manufacturing the color filter of this embodiment, the alignment mark 1 formed in advance is used.
Since the pigment-dispersed photoresist of another color is not applied on the image 1, the image becomes easy to recognize due to the high contrast when the image of the alignment mark 11 is captured. As a result, the alignment accuracy is improved. Also, by selecting the pigment dispersion photoresist coating area 14,
Since unnecessary resist coating is eliminated, liquid saving can be realized.

The method of manufacturing a color filter according to the present invention is not limited to the above-described embodiment, and for example, a conventional resist is used in place of the above-mentioned pigment-dispersed photoresist, and a well-known lithography method is used. You may form a stripe pattern and an alignment mark.
Further, when using the pigment dispersion photoresist, a plurality of pigments dispersed in the photosensitive resin are black, red, green,
It is not limited to the blue pigment.

[0036]

As described above, according to the method of manufacturing a color filter of the present invention, when the pattern of the first color of the plurality of colors is formed, the alignment mark formed outside the effective screen of the stripe pattern is included. Since the application area of the liquid coating agent used for pattern formation of the second and subsequent colors can be made smaller than the area, it is easy to recognize the image due to the high contrast when capturing the image of the alignment mark, and as a result, the alignment accuracy is improved. improves. Further, by selecting the pigment-dispersed photoresist coating area, unnecessary resist coating is eliminated and liquid saving can be realized.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining an example of a method for manufacturing a color filter according to the present invention.

FIG. 2 is an external perspective view of a microrod bar resist coating apparatus to which a microrod bar coating method using the color filter manufacturing method according to the present invention is applied.

FIG. 3 is a side view of the microrod bar resist coating apparatus.

FIG. 4 is a partially enlarged view of a micro rod bar of the micro rod bar resist coating apparatus.

FIG. 5 is a schematic diagram for explaining selection of a pigment dispersion photoresist coating area by the microrod bar resist coating device.

FIG. 6 is a cross-sectional view of a plasma addressed liquid crystal display device using a color filter.

FIG. 7 is a process drawing showing a manufacturing process of a color filter by a conventional photolithography method.

FIG. 8 is a flowchart for explaining a conventional process of forming a stripe pattern of a black mask.

[Explanation of symbols]

 3 Micro Rod Bar 7 Glass Substrate 10 Black Mask Stripe Pattern 11 Alignment Mark 12 Area Containing Alignment Mark 13 Pigment Dispersion Photoresist for Second and Later Colors 14 Pigment Dispersion Photoresist Coating Area for Second and Later Colors

Claims (5)

[Claims] 1. A color filter is manufactured by applying a liquid coating agent of a predetermined color onto a glass substrate and then repeating the process of forming the pattern of the predetermined color for a plurality of colors to form a pattern for a plurality of colors. In the method of manufacturing a color filter, when forming a pattern of the first color of the plurality of colors, the liquid used for pattern formation of the second color and later than the area including an alignment mark formed outside the effective screen of the pattern. A method for manufacturing a color filter, characterized in that a coating area of a coating agent is reduced. 2. The liquid coating agent of the predetermined color is applied to the glass substrate after being temporarily held in a recess formed between fine wires closely wound on a rod-shaped body. The method for manufacturing a color filter according to claim 1. 3. The method for producing a color filter according to claim 1, wherein the liquid coating agent is a pigment-dispersed resist having photosensitivity and a pigment dispersed therein. 4. The method for manufacturing a color filter according to claim 3, wherein the pigments of a plurality of colors are black, red, green and blue pigments. 5. The method of manufacturing a color filter according to claim 1, wherein the liquid coating agent is a color filter agent such as a pigment dispersion resin, an acrylic resin, or a polyimide resin.