JP3963329B2 - Curtain flow coater, coating method using the same and method for producing coating film for color filter - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a curtain flow coater suitably used for forming a color filter coating film used in a color display or a solid-state imaging device using a liquid crystal, a coating method using the same, and production of a coating film for a color filter. It is about the method.
[0002]
[Prior art]
In general, a color filter used for a display using a liquid crystal or the like is arranged on a transparent substrate such as a glass substrate while maintaining a certain positional relationship with three primary color patterns of red, green, and blue. One of the thin film coating methods on the transparent substrate is a curtain flow coater.
[0003]
As this coating method, for example, disclosed in Japanese Patent Application Laid-Open No. 5-11105, a system in which paint is discharged in a curtain form from a lip tip of a die called a die head, a T die, or a slit die, and applied to a substrate in a non-contact manner. belongs to. This method is characterized in that since the coating material supply path until it is discharged is sealed, there is little mixing of foreign matter and the viscosity change of the coating material is small.
[0004]
However, thin film coating by a curtain flow coater tends to be thin because the film thickness accuracy is poor for several meters at the coating start portion. For this reason, it has been difficult to apply a thin film to a small flat plate. However, in the case of a color filter, it is an indispensable problem in terms of quality to obtain a product having a uniform film thickness from the coating start part in coating on a flat plate.
[0005]
As a means for improving the film thickness uniformity at the coating start part, optimization of the die shape can be mentioned. A T-die is generally used as the current die shape. The T-die has a large liquid pool at the lip tip, and it takes time to become a stable liquid pool. For this reason, there are problems such as poor film thickness stability at the start of application and easy occurrence of application defects such as vertical stripes.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to make it possible to make the coating start portion uniform in film thickness, which is a conventional problem of curtain flow coaters.
[0007]
[Means for Solving the Problems]
The present invention has the following configuration.
[0009]
( 1 ) In the method of forming a puddle at the tip of the lip using a curtain flow coater and applying a paint on a flat plate, the angle of the tip of the doctor lip of the base as the curtain flow coater is less than 90 degrees, And a curtain flow coater in which the angle of the tip of the backup lip is 90 degrees .
[0010]
( 2 ) The manufacturing method of the coating film for color filters using the coating method of the coating material of said (1) .
[0011]
The curtain flow coater in the present invention will be described.
[0012]
Mouthpiece curtain flow coater according to the present invention, Ri least one tip 90 degrees less than Der doctor lip and backup lip, and angle of the tip of the backup lip portion and wherein the 90 ° der Rukoto . This is because when the tips of both lip portions are 90 degrees, the film thickness at the coating start portion is not stable. For greater stability of the film thickness of the coating start portion is a tip angle less than 90 degrees of the doctor lip, the angle of the tip of the backup lip is Ru 90 degrees der. The angle of the tip of the doctor lip is more preferably 30 to 80 degrees, and still more preferably 40 to 70 degrees. If it is less than 30 degrees, the amount of liquid pool at the tip of the lip portion increases, and the film thickness at the coating start portion becomes thin. Further, when the angle exceeds 80 degrees, the shape is almost the same as that of the T-die, and the film thickness uniformity at the coating start portion is lacking. On the other hand, the angle of the tip of the backup lip Ri substantially 90 degrees der, can be applied by a flat plate parallel to applying the paint. If there is no portion parallel to the substrate, the liquid pool at the tip of the lip becomes unstable during coating, and uneven coating in the width direction is likely to occur. The length of the portion parallel to the flat plate is preferably in the range of 0.5 to 20 mm, more preferably in the range of 1 to 5 mm. If the thickness is less than 0.5 mm, uneven coating in the width direction is likely to occur. If the thickness exceeds 20 mm, the die becomes heavier and the die is bent, and the clearance with the substrate cannot be kept constant. Lack of sex.
[0013]
FIG. 2 is a schematic view showing an example of a base of a curtain flow coater in the present invention. That is, the tip of the base 6 is composed of a doctor lip 12 and a backup lip 13, and the angle of the tip of the doctor lip 12 is about 50 degrees, and the angle of the tip of the backup lip 13 is substantially 90 degrees. Yes. In addition, 7 represents a push-pull bolt and 11 represents a film.
[0014]
Next, the coating method of the present invention will be described.
[0015]
The coating method according to the present invention is a method in which a liquid pool is formed at the tip of the lip using the curtain flow coater as described above, and the coating is applied on a flat plate.
[0016]
FIG. 1 is a schematic view showing an example of application by a curtain flow coater (slit die coater) in the present invention. That is, the paint 10 is supplied from the pipe 8 to the inside of the base 6 by the pump 9, and is composed of the lip 5 (the doctor lip 12 and the backup lip 13) that is the tip of the base 6 according to the conveyance of the flat plate 1 (in the direction of arrow A). ) Is applied onto the flat plate 1 adsorbed and fixed on the adsorption stage 2 in a curtain state to form a coating film 3. The uniformity of the coating film in the width direction is controlled by adjusting the distance between the lip 5 at the tip of the die and the distance between the flat plate 1 and the lip, that is, the clearance 4 for the paint discharged in the form of a curtain.
[0017]
The application of the paint by the curtain flow coater of the present invention is not limited to the method using a slit die coater, and may be a method using a die head, a T die, or the like. Further, the coating material supply means is not limited to a pump, and may be a system such as compressed air.
[0018]
When the paint is a paint for forming a coating film for a color filter, it is particularly required that the appearance of the paint film is good, and therefore the coating method of the paint by the curtain flow coater of the present invention is particularly preferably used.
[0019]
Hereinafter, the case where the coating method of the present invention is applied to the color filter coating film formation will be described.
[0020]
In the case of forming a color filter coating film, a transparent flat plate is used as the flat plate. Although it does not specifically limit as a transparent flat plate, The transparent flat plate of 70% or more of total light transmittances, such as plastic flat plates, such as a polycarbonate and a polymethylmethacrylate, a plastic film, and a glass plate, is used preferably. Of these, a glass plate is more preferably used.
[0021]
The type of paint 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 these photosensitive resins are preferable. Used. In addition, coloring materials such as dyes or pigments may be dispersed and mixed in these resins.
[0022]
Although the film thickness after application | coating to a transparent flat plate is not specifically limited, In the state of a dry coating film, the range of 0.1-5.0 micrometers is preferable, More preferably, it is 0.2-3.0 micrometers. The range of is preferably used. If the coating film after drying is less than 0.1 μm, vertical stripes are generated in the drying coating film, which is a problem in quality. On the other hand, when it exceeds 5.0 μm, the smoothness of the dried coating film is inferior. In addition, the amount of paint used is increased, which is not economical.
[0023]
Examples of the method for producing the color filter include the following methods, but are not limited thereto. First, a light shielding layer having a fine pattern is formed on a transparent flat plate. A thermosetting paint to which an adhesive is added is applied on 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 onto the thermosetting coating, mask exposure is performed using an ultrahigh pressure mercury lamp or the like, and then the thermosetting coating is etched using the relief pattern as a mask. Subsequently, the positive photoresist is peeled off, and then heated and fired at 200 to 350 ° C. to thermally cure the coating film. The above process is repeated for red, green, and blue to form predetermined red, green, and blue fine patterns to obtain color filters.
[0024]
The drying temperature of the paint is preferably in the range of 50 to 160 ° C, more preferably in the range of 80 to 130 ° C. If it is less than 50 degreeC, drying time is long and production efficiency will worsen. On the other hand, at 160 ° C. or higher, thermosetting proceeds and insolubilizes in the developer.
[0025]
On the other hand, in the case of a photosensitive paint to which a colorant is added, a light-shielding layer having a fine pattern is formed on a transparent flat plate, and a photosensitive paint to which a colorant is added is applied on the light-shielding layer. Dry at temperature to form a photosensitive coating. Subsequently, mask exposure is performed using an ultra-high pressure mercury lamp or the like, and the photosensitive paint is photocured. Thereafter, the uncured photosensitive coating on the light shielding layer is developed and etched. The above process is repeated for red, green, and blue to form predetermined red, green, and blue fine patterns to obtain color filters.
[0026]
If necessary, a paint that does not contain a colorant may be applied to the red, green, and blue fine patterns for the purpose of improving the protective film and smoothness, thereby forming a color filter.
[0027]
The coating method according to the present invention is effective for coating various coating materials for forming a color filter coating film in the color filter manufacturing process described above. That is, red, green and blue fine pattern forming paints, light shielding layer forming paints, protective layer forming paints and the like.
[0028]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto.
[0029]
Example 1 and Comparative Example 1
Coating was carried out on a glass substrate using the coating apparatus and the base shown in FIG. 1 and FIG. A glass substrate having a size of 300 × 400 mm and a thickness of 1.1 mm was used. In addition, N-methylpyrrolidone solvent, salt brominated phthalocyanine green (CI Pigment Green 36) and disazo yellow HR (CI PI Pigment Yellow 83) pigment are added and dispersed as a paint. The coating was carried out at a coating speed of 2 m / min in a state of 8 wt% and a viscosity of 100 cp, and dried at 120 ° C. for 10 minutes.
[0030]
On the other hand, using the conventional curtain flow coater shown in FIG. 3 (the tips of the doctor lip and the backup lip are 90 degrees, and both the tips are parallel to the flat plate), the coating is performed in the same manner as in Example 1. (Comparative Example 1).
[0031]
In FIG. 4, the film thickness distribution results of the coated substrate obtained in Example 1 and the coated substrate obtained in Comparative Example 1 are compared and shown.
[0032]
In Comparative Example 1, the film thickness is thin from the coating start part to 200 mm with respect to the central part of the coating substrate, and the film thickness is nonuniform. On the other hand, in Example 1, the film thickness distribution is not as in Comparative Example 1, and the film thickness is already stable at 10 mm from the coating start portion. Furthermore, there was no coating unevenness during coating, and a good coating film was obtained.
[0033]
【The invention's effect】
By applying the curtain flow coater and the coating method according to the present invention, the film thickness uniformity from the coating start part can be remarkably improved, so that the vertical stripes at the time of coating that have conventionally occurred can hardly occur. Therefore, a good quality coating film can be obtained. Therefore, when forming a coating film for a color filter that is required to have a good appearance, it is particularly preferably used in the case of single-wafer coating that requires stability of the film thickness from the coating start part. Can do.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example of application by a curtain flow coater according to the present invention.
FIG. 2 is a schematic view showing an example of a base of a curtain flow coater according to the present invention.
FIG. 3 is a schematic view showing an example of a base of a conventional curtain flow coater.
4 is a film thickness distribution diagram of the coated substrate obtained in Example 1 and the coated substrate obtained in Comparative Example 1. FIG.
[Explanation of symbols]
1: Flat plate 2: Adsorption stage 3: Coating film 4: Clearance 5: Lip 6: Base 7: Push-pull bolt 8: Pipe 9: Pump 10: Paint 11: Film 12: Doctor lip 13: Backup lip

Claims (4)

In a method of forming a liquid pool at the tip of a lip portion using a curtain flow coater and applying paint on a flat plate, the angle of the tip of the doctor lip portion of the base as the curtain flow coater is less than 90 degrees, and a backup lip A method of applying a paint, comprising using a curtain flow coater having a tip angle of 90 degrees . In the method in which a liquid pool is formed at the tip of the lip using a curtain flow coater and the paint is applied onto a flat plate, the angle of the tip of the doctor lip of the base as the curtain flow coater is 30 to 80 degrees, and backup A method of applying a paint, characterized by using a curtain flow coater in which the angle of the tip of the lip portion is 90 degrees. The coating method according to claim 1 or 2 , wherein the coating is a coating for forming a coating film for a color filter. The manufacturing method of the coating film for color filters which uses the coating method of the coating material of Claim 3 .

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