JPH078894A - Formation of coating film - Google Patents

Abstract

(57) [Summary] The present invention is a method of forming a coating film on a flat plate by applying a paint on a flat plate and drying the same, leaving a portion not coated with the paint on the peripheral portion of the flat plate. A method for forming a coating film and a coating film for a color filter, characterized in that the coating material is applied by a curtain flow. According to the present invention, since the edge portion and the back surface of the transparent flat plate are not contaminated with the paint, the productivity of the color filter is remarkably improved. Furthermore, since a thin film is applied uniformly only on the surface of the transparent flat plate, the loss of the paint is very small, and a high quality and low cost color filter can be produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a coating film which is particularly preferably used as a coating film for a color filter used in a color display using a liquid crystal or a solid-state image pickup device.

[0002]

2. Description of the Related Art In general, a color filter used for a display using liquid crystal is arranged on a transparent substrate such as a glass substrate with a pattern of three primary colors of red, green and blue arranged in a fixed positional relationship. There is. As a thin film coating method on the transparent substrate, there are a conventional spin coater, roll coater, bar coater and the like.

The spin coater is a method widely used for photoresist coating of semiconductor wafers. In the manufacture of a color filter, for example, it is disclosed in JP-A-63-107769, and a paint is added to the center of the surface of a rotating glass substrate to form a coating film. This coating method has a problem that the thickness of the coating film is uniform, but the amount of the coating material used is large in order to obtain a predetermined film thickness, and the economical efficiency is poor. Further, since the coating material adheres to the edge portion and the back surface of the glass substrate, not only an extra step for cleaning the edge portion and the back surface is required, but also the quality is easily deteriorated. Further, since the paint is scattered inside the device, there is a problem that the paint attached inside the device is solidified and is generated as a foreign substance.

The roll coater is of a type in which the coating material is transferred onto a glass substrate via a rubber roll, and is suitable for coating a large size substrate. Therefore, a photoresist is used for patterning a thermal head, an image sensor, a photomask or the like. It is used for coating. However, since a rubber roll is basically used, there is a problem that the coating film lacks smoothness and durability.

The bar coater is a method for applying a coating material on a substrate by using a bar in which a thin wire is wound around a rod, and is disclosed in, for example, Japanese Patent Laid-Open No. 02-258081. This method has a drawback in that the wire wound around the rod comes into contact with the glass substrate, so that streaks easily form in the coating film.

[0006] On the other hand, the curtain flow coater is a system in which paint is discharged in a curtain shape from the lip tip of a die called a die head, a T die, and a slit die, and is applied to a substrate in a non-contact manner. In this method, the paint supply path until it is discharged is sealed, so there is no mixing of foreign matter,
Furthermore, it has the feature that the viscosity of the paint does not change significantly.

However, in the thin film coating on a long substrate by a curtain flow coater, the film thickness accuracy is poor for several meters at the coating start portion, which makes it difficult to apply the thin film on a small flat plate. Further, as a coating on a flat plate by a curtain flow coater, it is a thick film coating of 20 μm or more for plywood, slate, etc. When a thin film coating of less than 10 μm is performed like a spin coater or a roll coater,
There is a problem of lacking in-plane film thickness uniformity.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a transparent flat plate which is a subject up to now while keeping the characteristics of the conventional curtain flow coating, such as less contamination of foreign substances and less change in paint viscosity. It is to be able to apply a thin film to. Furthermore, the edge of the transparent plate and the back surface are not contaminated with the paint discharged from the die, and the in-plane film thickness uniformity is improved,
An object of the present invention is to provide a method for forming a coating film for a color filter, which is excellent in economic efficiency.

[0009]

The present invention has the following configuration.

(1) In a method of forming a coating film on a flat plate by applying the paint on a flat plate and drying the same, the paint is applied by a curtain flow, leaving a non-application portion on the peripheral edge of the flat plate. A method for forming a coating film, comprising:

(2) In a method of applying a coating material on a transparent flat plate and drying it to form a coating film for a color filter on the transparent flat plate, leaving a portion not coated with the coating material on the peripheral edge of the transparent flat plate, A method for forming a coating film for a color filter, which comprises applying a paint by curtain flow.

Next, a method for forming a coating film according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view showing an example of coating (slit die coater) of a coating material according to the present invention by curtain flow. That is, the paint 10 is supplied from the pipe 8 to the inside of the die 6 by the pump 9, and is adsorbed and fixed on the adsorption stage 2 in a curtain state from the lip 5 which is the tip of the die 6 as the flat plate 1 is conveyed (in the direction of arrow A). Flat plate 1
Applied over. The uniformity of the coating film depends on the distance between the lips 5 at the tip of the die and the flat plate
It is controlled by adjusting the distance between the lip 5 and the clearance 5, that is, the clearance 4.

Lip 5 at the tip of the base used in the present invention
Is not particularly limited, but is 20 to 400 μ
The range of m is preferable, and more preferably 50 to 250 μm.
Is the range. If the distance between the lips 5 is less than 20 μm or exceeds 400 μm, the shape of the paint discharged from the lips 5 becomes unstable, and vertical stripes are likely to appear in the coating film.

The clearance 4 has an interval of 10 to 500 μm.
The range of m is preferable, and more preferably 50 to 250 μm.
Is the range. When the thickness is less than 10 μm, the flatness of the transparent flat plate 1 is inferior, so that the tip of the lip 5 comes into contact with the transparent flat plate 1 and vertical streaks are easily formed in the coating film. On the other hand, when the clearance 4 exceeds 500 μm, the film-like cracks are likely to occur on the curtain-shaped coating film at the time of ejection.

The coating by the curtain flow according to the present invention is not limited to the method using a slit die coater, but may be a method using a die head, a T-die or the like. Further, the paint supply means is not limited to the pump, and may be a system such as compressed air.

The coating can be applied, for example, by the following method, while leaving a portion of the flat plate on which the coating is not applied.

First, in the width direction of the flat plate 1, as shown in FIG. 2, the width of the film 11 incorporated in the die 6 can be made equal to the coating film width or a few mm shorter. By such a method, both side edges 12 of the flat plate 1 in the width direction and the back surface 13 of the flat plate 1 can be prevented from being soiled. FIG. 3 shows an example of a transparent flat plate on which a coating film is formed by applying a coating material and drying it.

On the other hand, the coating start portion and the coating end portion can be achieved by adjusting the sequence as shown in FIGS. 4 and 5.

As for the coating start portion, as shown in FIG. 4, the flat plate 1 is conveyed immediately below the lip 5 which is the tip of the die 6 and stopped. Then, after starting the discharge of the coating material from the tip of the lip 5 inside the edge portion on the flat plate, the transport of the flat plate 1 is started and the coating is performed. The stop position of the flat plate 1 is not particularly limited, but normally, the discharge start position is preferably in the range of 1 to 20 mm at the end of the edge portion 12 of the flat plate 1, and more preferably in the range of 2 to 10 mm. Is. If this distance is less than 1 mm, the edge portion 12 of the flat plate 1 is likely to be contaminated with the coating material and becomes a source of foreign matter. When it exceeds 20 mm, it is uneconomical because the loss of the flat plate 1 is large.

Regarding the coating end portion, after the discharge from the tip of the lip 5 is completed inside the edge portion on the flat plate, as shown in FIG. 4, at the same position as the coating start portion from the edge portion 12 of the flat plate 1. The conveyance of the flat plate 1 is completed.

By adjusting the sequence as described above, the edge portion 12 and the back surface 13 on both sides of the flat plate 1 in the conveying direction are not contaminated with the paint, but only within the surface (the peripheral portion is left uncoated). ) Can be applied.

The stop time of the flat plate 1 (from the start of discharge to the start of flat plate transfer, and from the end of discharge to the end of flat plate transfer)
Is preferably in the range of 0.2 to 10 seconds, and more preferably in the range of 0.3 to 3 seconds. If it is less than 0.2 seconds, the coating thickness at the coating start portion and the coating end portion is small, and if it exceeds 10 seconds, the film thickness at the coating start portion and the coating end portion is too large. Be uniform.

The case where the coating film forming method of the present invention is applied to a coating film for a color filter will be described below.

In the case of a color filter coating film, a transparent flat plate is used. The transparent flat plate is not particularly limited, but a transparent flat plate having a total light transmittance of 70% or more, such as a plastic flat plate of polycarbonate, polymethylmethacrylate or the like, a plastic film or a glass plate is preferably used. Of these, a glass plate is more preferably used.

The type of coating material is not particularly limited, but one or a mixture of two or more of acrylic resin, polyester resin, polyvinyl alcohol resin, polyamic acid resin, polyimide resin and the like, and photosensitive resins thereof, etc. Is preferably used. A colorant such as a dye or a pigment may be dispersed and mixed with these resins before use.

The film thickness after coating on the transparent flat plate is not particularly limited, but is 0.1 to 5.0 μm in the dried state.
Is preferable, and more preferably 0.2 to 3 μm. If the coating film after drying is less than 0.1 μm, vertical streaks are generated in the dried coating film, which is a quality problem. On the other hand, 5 μm
If it exceeds the range, the amount of paint used will be large and the economy will be poor.

As described above, by forming the color filter coating film according to the present invention, it is possible to uniformly coat the thin film only on the inside surface without contaminating the edge portion and the back surface of the transparent plate with the coating material, and to obtain high quality. Therefore, it is possible to provide a color filter having excellent economical efficiency.

Examples of the method for manufacturing the color filter include, but are not limited to, the following methods. First, a light shielding layer having a fine pattern is formed on a transparent flat plate. A thermosetting paint containing a colorant is applied onto the light shielding layer and dried at a temperature of 50 to 150 ° C. to form a thermosetting coating film. Subsequently, a positive photoresist is applied on the thermosetting coating film, mask exposure is performed using an ultra-high pressure mercury lamp or the like, and then the positive photoresist is developed.
After etching to form a relief pattern, the thermosetting coating film is etched using the relief pattern as a mask. Then, after peeling off the positive photoresist, the coating film is heat-baked at about 200 to 350 ° C. to thermally cure the coating film. The above steps are repeated for red, green, and blue to form predetermined red, green, and blue fine patterns to form a color filter.

The drying temperature of the paint is preferably 50 to 150 ° C, more preferably 80 to 125 ° C. If the temperature is lower than 50 ° C, the drying time will be long and the production efficiency will be poor. On the other hand, when the temperature exceeds 150 ° C., thermosetting progresses and becomes insoluble in the developing solution.

On the other hand, in the case of a photosensitive coating containing a colorant, a light-shielding layer consisting of a fine pattern is formed on a transparent flat plate, and the photosensitive coating containing a colorant is applied onto the light-shielding layer, and then 50 to 50 Dry at a temperature of 150 ° C. to form a photosensitive coating film. Subsequently, mask exposure is performed using an ultra-high pressure mercury lamp or the like to photo-cur the photosensitive coating film. Then, the uncured photosensitive coating film on the light shielding layer is developed and etched. The above steps are repeated for red, green, and blue to form predetermined red, green, and blue fine patterns to form a color filter.

If necessary, a paint containing no colorant may be applied on the red, green and blue fine patterns to form a protective film and a smoothness to form a color filter.

The method of forming a coating film by curtain flow according to the present invention is effective for coating various coating materials in the above color filter manufacturing process.

[0034]

[Function] As described above, a paint having a width equal to the width of the coating film or a width of a few millimeters shorter than the width of the coating film is used between the lips of the base to coat the paint from the surface closer to one edge of the transparent flat plate. Discharge in a flow state, and after a predetermined time has passed, a transparent flat plate is conveyed and applied.

At the end of coating, the conveyance of the transparent flat plate and the discharge of the coating material are stopped at the position where the lip portion at the tip of the die comes closer to the other edge of the transparent flat plate. With such a coating method, a uniform thin film can be coated only on the surface of the transparent flat plate.

[0036]

The present invention will be described in detail below with reference to examples, but the invention is not limited thereto.

Example 1 Using the die 6 shown in FIG. 1 and the in-plane coating method of the transparent flat plate shown in FIGS. 4 and 5, a size of 300 mm × 40.
On a glass substrate 1 having a thickness of 0 mm and a thickness of 1.1 mm, an N-methylpyrrolidone solvent and chlorobrominated phthalcyanine green (C.
I. Pigment Green 36) and Disazo Yellow HR
(C. I. Pigment Yellow 83) Polyamic acid paint containing a pigment added and dispersed therein has a solid content of 8 wt% and a viscosity of 150 c.
The coating was carried out with p and dried at 110 ° C. for 10 minutes.

A thickness of 100 μ is provided between the lips 5 of the base 6.
Set a polyester film 11 with a width of 290 mm with and press the space between the lip 5 of the mouthpiece 6 with the pulling bolt 7.
Finely adjusted to 00 μm. The die 6 in this state was set at a position 5 mm from the edge end of the glass substrate 1 so that the clearance 4 was 100 μm. After that, the coating material 10 is discharged by the pump 9 for 0.5 seconds to form a curtain-shaped film between the glass substrate 1 and the lip 5, and then the glass substrate 1 is moved to 1 m / m.
The application was started by transporting at a speed of 3 m / min and 5 m / min. At the end of coating, the discharge of the coating material 10 is stopped at a position 5 mm from the edge of the glass substrate 1, and 0.3 seconds later,
The conveyance of the glass substrate 1 was stopped and the coating was completed. As a result, there was no vertical stripe at any coating speed, and a good coating film was obtained.

There was no stain on the back surface and the edge portion of the glass substrate due to the paint, and a uniform coating film was formed within 4 mm from the edge ends of the four sides.

Example 2 In the same manner as in Example 1, an acrylic resin (Cotax, manufactured by Toray) in which a cellosolve acetate solvent and a dianthraquinone nil red (CI Pigment Red 177) pigment were added and dispersed was used as a solid content. It was applied at 30 wt% and a viscosity of 25 cp and dried at 130 ° C. for 15 minutes. Further, phthalcyanine blue (CI Pigment Blue 154) was applied in the same solvent and resin at a solid content of 30 wt% and a viscosity of 18 cp, and dried at 130 ° C. for 15 minutes. As a result, a good coating film was obtained as in Example 1. It should be noted that there was no stain on the back surface and the edge portion of the glass substrate, and uniform coating was possible within the surface.

Example 3 In the same manner as in Example 1, the size was 300 mm × 350 m.
m, 1.1 mm thick, soda lime glass substrate 1 with SiO ₂ coated with a photoresist having a viscosity of 30 cp, 1
It was dried at 00 ° C for 10 minutes.

There is a thickness of 50 μm between the lips 5 of the base 6.
Set a polyester film 11 with a width of 290 mm with and press the space between the lip 5 of the mouthpiece 6 with the pulling bolt 7.
Fine-tuned to 0μ. Place the die 6 in this state on the position 5 mm from the edge end of the glass substrate 1 so that the clearance 4 is 50
It was set so as to be μm. Then paint 1 with pump 9.
0 is discharged for 0.7 seconds to form a curtain-like film between the soda lime glass substrate 1 with SiO ₂ and the lip 5, and then S
The soda lime glass substrate 1 with iO ₂ was conveyed at a speed of 3 m / min to start coating. At the end of coating, the discharge of the coating material 10 was stopped at a position 5 mm from the edge of the glass substrate 1, and 0.2 seconds later, the transportation of the soda lime glass substrate 1 with SiO ₂ was stopped and the coating was finished. . As a result, the coating film width was slightly widened to 296 mm, but uniform coating was possible only within the surface. A good coating film was obtained without vertical streaks.

[0043]

EFFECTS OF THE INVENTION According to the present invention, foreign matter is less mixed,
While maintaining the characteristic of the conventional curtain flow coat that the change in paint viscosity is small, the edge portion and the back surface of the transparent flat plate are not contaminated with the paint, so that the productivity of the color filter is significantly improved. Furthermore, since a thin film is applied uniformly only on the surface of the transparent flat plate, the loss of the paint is very small, and a high quality and low cost color filter can be produced.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of coating (slit die coater) by a curtain flow according to the present invention.

2 is a schematic diagram showing a right side view of coating by the curtain flow shown in FIG. 1. FIG.

FIG. 3 is a schematic view of a flat plate on which a coating film is formed by applying and drying a paint.

FIG. 4 is a schematic view of a coating material application starting portion of a flat plate.

FIG. 5 is a schematic view of a coating application completion portion of a flat plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flat plate 2 Adsorption stage 3 Coating film 4 Clearance 5 Lip 6 Base 7 Push / pull bolt 8 Piping 9 Pump 10 Paint 11 Film 12 Edge of flat plate 13 Back side of flat plate

Claims (7)

[Claims] 1. A method of applying a coating material on a flat plate and drying it to form a coating film on the flat plate, wherein the coating material is applied by curtain flow, leaving a non-application portion on the peripheral portion of the flat plate. A method for forming a coating film characterized by the above. 2. The conveyance of the flat plate is started after the discharge of the paint is started inside the edge portion of the flat plate.
The method for forming a coating film as described above. 3. The conveyance of the flat plate is terminated after the paint is discharged inside the edge portion of the flat plate.
Or the method for forming a coating film according to 2. 4. A method for forming a color filter coating film on a transparent flat plate by applying the paint on the transparent flat plate and drying the paint, leaving a portion of the transparent flat plate to which no paint is applied, leaving the paint. A method for forming a coating film for a color filter, characterized in that the composition is applied by curtain flow. 5. The method for forming a coating film for a color filter according to claim 4, wherein the coating of the transparent flat plate is started after the discharge of the paint is started inside the edge portion of the transparent flat plate. 6. The method for forming a coating film for a color filter according to claim 4, wherein the transport of the transparent plate is finished after the coating material is discharged inside the edge portion of the transparent plate. 7. The color filter according to claim 4, wherein the thickness of the color filter coating film formed on the transparent flat plate is in the range of 0.1 to 5.0 μm after drying. For forming coating film for automobile.