JP4857673B2 - Roll coater and color filter manufacturing method - Google Patents

Description

  The present invention relates to a roll coater using a rubber applicator roll having a body surface, and in particular, when a photoresist is applied, a coating film having a uniform film thickness over the entire surface of a glass substrate over a long period of time. It is related with the roll coater which can form.

FIG. 3 is a plan view schematically showing an example of a color filter used in the liquid crystal display device. 4 is a cross-sectional view of the color filter shown in FIG. 3 taken along line XX ′.
As shown in FIGS. 3 and 4, the color filter used in the liquid crystal display device has a black matrix (51) and colored pixels (52) sequentially formed on a glass substrate (50).
3 and 4 schematically show a color filter, and 12 colored pixels (52) are shown. In an actual color filter, for example, several hundreds of pixels are displayed on a 17-inch diagonal screen. A large number of colored pixels of about μm are arranged.

The black matrix (51) is a matrix having light shielding properties, and the colored pixels (52) have, for example, red, green, and blue filter functions.
The black matrix determines the position of the colored pixels of the color filter, makes the size uniform, and shields unwanted light when used in a display device, making the image of the display device uniform and uniform. In addition, it has a function of making an image with improved contrast.

This black matrix (51) is an example in which a resin is used as a black matrix material on a glass substrate (50).
The black matrix (51) is formed on the glass substrate (50) by, for example, a photolithography method using a black photoresist for forming a black matrix. It is called the resin black matrix (51).

The peripheral edge of the color filter is a part called a picture frame. The color filter shown in FIGS. 3 and 4 is an example in which the resin black matrix is formed up to the frame portion, that is, the edge of the peripheral edge of the color filter.
The direct light from the backlight is shielded to the edge of the peripheral edge of the color filter, and the function of reducing the stray light incident from the end face of the color filter and improving the contrast of the image is provided.

  The colored pixel (52) is a photolithography method using a negative colored photoresist in which a pigment such as a pigment is dispersed on the glass substrate (50) on which the resin black matrix (51) is formed. That is, it is formed as a colored pixel by exposure through a photomask to the coating film of the colored photoresist and development processing. Red, green, and blue colored pixels are sequentially formed.

The resin black matrix, for example, causes internal reflection in a liquid crystal display device that occurs when a metal such as chromium is used as a black matrix (not shown) when using a high-brightness backlight such as a television. In order to suppress a low-reflection resin black matrix, or in order to suppress an electric field disturbance in a liquid crystal display device when used in, for example, an IPS (In Plane Switching) system, a high insulation is required. It has been adopted when a functional resin black matrix is required. However, the black matrix is gradually shifting from a black matrix using a metal such as chromium to a resin black matrix.

When a large number of color filters are manufactured, a color filter corresponding to a single liquid crystal display device is manufactured in a state where it is applied to a large glass substrate. For example, a 17-inch diagonal color filter is manufactured by attaching four faces to a large glass substrate of about 650 mm × 850 mm.
As the size of the glass substrate increases, the resin black matrix formed by photolithography using a black photoresist rather than the black matrix using a metal such as chromium as the black matrix material and forming a thin film with a vacuum device. The price is more advantageous, and the transition to resin black matrix is gradually progressing.
This transition is likely to become significant as the glass substrate becomes larger. Moreover, it tends to avoid using metals such as chromium in consideration of the environment.

Conventionally, in a manufacturing process of a liquid crystal display device, as a coating device such as a photoresist, a spin coater that rotates a glass substrate and spreads the coating solution after dropping the coating solution from a nozzle to the center of the glass substrate has been often used. It was.
This spin coater has the advantage of high film thickness accuracy, but if the glass substrate becomes large, it is difficult to implement it due to mechanical restrictions such as a motor, and more than 95% of the coating solution is wasted. There is a disadvantage that it is wasted.

For this reason, for example, in a glass substrate having a size of about 550 mm × 650 mm, a slit & spin coater (also called a coat & spin coater) has started to be used. This is a method of increasing the uniformity of the film thickness by applying the coating liquid to the glass substrate from the slit nozzle and then rotating the glass substrate.
In this method, although the utilization rate of the coating solution is greatly improved to 30 to 40%, the mechanical constraints such as the motor are the same, so it is difficult to further increase the size of the apparatus.

Instead of these coaters, the development and practical use of highly accurate slit coaters are progressing. The slit coater is a method of applying a coating solution to a glass substrate from a slit nozzle while horizontally moving a surface plate on which a glass substrate is placed or an application head, and is 1 m × 1.3 m or 1.5 m × 1. A glass substrate having a size of about 8 m can be accommodated.
However, even if the glass substrate is further increased in size, a highly accurate roll coater has been developed as a coating apparatus that can efficiently and inexpensively apply.

FIG. 1 is a cross-sectional view schematically showing an outline of an example of a roll coater. As shown in FIG. 1, the roll coater (10) schematically shown includes a metering roll (1), a knife roll (2), and an applicator roll (3).
The metalling roll (1) is a metal flat roll using, for example, SUS. The knife roll (2) is, for example, a metal flat roll using SUS or the like, and the knife roll (2) is fixed without rotating. The knife roll (2) is also referred to as a comma roll, and has a notch on the body surface. On the roll coater, the supplied coating liquid is separated to the applicator roll (3) side at the intersection of the cylinder surface and the upper portion of the side wall of the notch.

The applicator roll (3) is, for example, a flat roll in which a rubber layer is provided on the body surface of a metal core roll. As the rubber, for example, EPDM (Ethrene / propylene / diene) is used.
The coating liquid supplied between the metering roll (1) and the knife roll (2) has a film thickness due to the gap between the body surface of the metalling roll (1) and the intersection of the knife roll (2). Adjusted to form a film on the metering roll (1).
This coating is transferred from the metering roll (1) to the applicator roll (3) and subsequently transferred from the applicator roll (3) onto the glass substrate (50) for application onto the glass substrate (50). The liquid is applied.
In addition, in FIG. 1, the arrow represents the rotation direction of a roll, and the advancing direction, respectively.

However, for example, when the black photoresist is applied using such a roll coater, it is difficult to form a coating film having a uniform film thickness on the entire surface of the glass substrate over a long period of time.
Table 1 shows, as an example, the film thickness of the coating film when a black photoresist is applied onto a glass substrate having a width (a) of 400 mm × length (b) of 320 mm, using the roll coater having a roll width of about 410 mm. The distribution is shown. Table 1 shows the measured values when 0.5 hours have elapsed after the start of coating.

図２は、塗膜の膜厚の測定ポイントの説明図である。図２において、幅（ａ）４００ｍｍのガラス基板の進行方向は白太矢印で示す方向である。符号（Ａ）は、ガラス基板の進行方向の先端部、（Ｂ）は中央部、（Ｃ）は後端部を表している。数値（０）は、幅（ａ）４００ｍｍのガラス基板の幅方向の中央部、数値（−１９５）は中央部（０）から１９５ｍｍ離れた図２中、左端部、数値（１９５）は中央部（０）から１９５ｍｍ離れた図２中、右端部を表している。
表１に示すように、ガラス基板の左端部及び右端部において、塗膜の膜厚が著しく厚い状態である。
尚、図５は、表１に示すデータをグラフに表したものである。

FIG. 2 is an explanatory diagram of measurement points of the film thickness of the coating film. In FIG. 2, the traveling direction of the glass substrate having a width (a) of 400 mm is a direction indicated by a white arrow. Symbol (A) represents the front end portion in the traveling direction of the glass substrate, (B) represents the center portion, and (C) represents the rear end portion. The numerical value (0) is the central part in the width direction of the glass substrate having a width (a) of 400 mm, the numerical value (-195) is 195 mm away from the central part (0) in FIG. 2, and the numerical value (195) is the central part. The right end part in FIG. 2 which is 195 mm away from (0) is shown.
As shown in Table 1, the film thickness of the coating film is remarkably thick at the left end and the right end of the glass substrate.
FIG. 5 is a graph showing the data shown in Table 1.

The present inventor has scrutinized the cause of the phenomenon as described above, and as a result, the rubber layer of the applicator roll (3) is gradually swollen by the solvent in the black photoresist, and the body surface of the applicator roll (3). Has been found to be due to so-called barrel-shaped deformation in the axial direction.
FIG. 6 is an explanatory diagram showing swelling of the rubber layer after an applicator roll using EPDM as a material for the rubber layer is immersed in a black photoresist for 24 hours. The vertical axis represents the amount of swelling of the rubber layer, which is the amount of increase in diameter in an applicator roll having a diameter of 150 mm. It is shown that there is little swelling at both ends of the applicator roll having a width (a) of 410 mm, and that swelling is large in regions other than both ends.
JP-A-6-265715

The present invention has been made to solve the above problems, and even when a photoresist is applied by using a roll coater using a rubber applicator roll on its body surface, it remains on the glass substrate for a long time. It is an object of the present invention to provide a roll coater capable of forming a coating film having a uniform film thickness on the entire surface.
It is another object of the present invention to provide a color filter manufacturing method in which a photoresist is applied using the roll coater to form a uniform pattern on the entire surface of a glass substrate.

The present invention provides a roll coater for a glass substrate having an applicator roll whose body surface is EPDM (Ethrene / propylene / diene) .
1) The constant width diameter (D1) of the central portion (W1) in the axial direction of the applicator roll is smaller than the diameter (D2) of the left end portion (W2-L) in the axial direction and the right end portion (W2-R) in the axial direction. ,
2) The diameter (D3) of the left intermediate portion (W3-L) between the left end (E1) of the axial center portion (W1) and the right inner end (E2) of the axial left end portion (W2-L) is Gradually increasing from the left end (E1) to the right inner end (E2),
3) The diameter (D3) of the right intermediate portion (W3-R) between the right end (F1) of the axial center portion (W1) and the left inner end (F2) of the axial right end portion (W2-R) is The roll coater is characterized by gradually increasing from the right end (F1) toward the left inner end (F2).

The present invention also provides a roll coater characterized in that the coating solution used in the roll coater according to claim 1 is a photoresist.

The present invention is the roll coater according to claim 2 , wherein the photoresist is a photoresist used for forming a pattern constituting a color filter.

Moreover, this invention uses the roll coater of any one of Claims 1-3 , apply | coats a photoresist on a glass substrate, and manufactures a color filter, The manufacturing method of the color filter characterized by the above-mentioned. It is.

  In the present invention, the diameter (D1) of the center part in the axial direction of the applicator roll whose rubber surface is rubber is smaller than the diameter (D2) of the left end part in the axial direction and the right end part in the axial direction. The diameter (D3) of the left middle portion with the right inner end of the left end portion gradually increases from the left end toward the right inner end, and the right middle between the right end of the axial center and the left inner end of the axial right end Since the diameter of the portion (D3) is a roll coater that gradually increases from the right end toward the left inner end, even if a photoresist is applied, a coating having a uniform film thickness over the entire surface over a long period of time. A roll coater capable of forming a film is obtained.

  In addition, the present invention is a color filter manufacturing method in which a color filter is manufactured by applying a photoresist on a glass substrate using the roll coater, so that a resin black matrix, colored pixels, and the like are uniformly distributed over the entire surface of the glass substrate. It becomes a manufacturing method of the color filter which can form a simple pattern.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 7 is a cross-sectional view schematically showing an example of an applicator roll in the roll coater according to the present invention. The applicator roll shown in FIG. 7 has a barrel surface made of rubber.

As shown in FIG. 7, the diameter (D1) of the central portion (W1) in the axial direction of the applicator roll is larger than the diameter (D2) of the left end portion (W2-L) in the axial direction and the right end portion (W2-R) in the axial direction. small. The diameter (D3) of the left intermediate portion (W3-L) between the left end (E1) of the axial center portion (W1) and the right inner end (E2) of the axial left end portion (W2-L) is: It gradually increases from the left end (E1) toward the right inner end (E2). The diameter (D3) of the right middle portion (W3-R) between the right end (F1) of the axial center portion (W1) and the left inner end (F2) of the axial right end portion (W2-R).
3) gradually increases from the right end (F1) toward the left inner end (F2).
That is, the cross section of the body of the applicator roll in the present invention has a so-called pincushion type.

  Thus, in order to make the diameter (D1) of the central portion in the axial direction smaller than the diameter (D2) of the left end portion in the axial direction and the right end portion in the axial direction, when the photoresist is applied for a long time, This is because even if the rubber is swollen by the solvent, the influence on the film thickness of the coating film is reduced. Thereby, it becomes a roll coater which can form the coating film which has a uniform film thickness on the whole surface on a glass substrate over a long time.

  The difference between the diameter (D1) at the central portion in the axial direction and the diameter (D2) at the left and right axial ends is the type and thickness of the rubber used, the type of solvent in the photoresist, and the applicator roll. Since it differs depending on the body width and diameter, it is set appropriately. Specifically, for example, when the width (W) of the applicator roll is 420 mm and the diameter (D2) of the axial left end and the axial right end is 150.0 mm, the diameter ( D1) is about 149.9 mm, the central portion in the axial direction is about 388 mm, the left end portion in the axial direction and the right end portion in the axial direction are about 11 mm each, and the middle left portion and the right middle portion are about 5 mm each.

  Table 2 uses a roll coater provided with the applicator roll in the present invention having a roll width of about 420 mm, and on a glass substrate having a width (a) of 400 mm × length (b) of 320 mm as in Table 1 above. It shows the film thickness distribution of the coating film when a black photoresist is applied. Table 2 shows measured values when 0.5 hours have elapsed after the start of coating.

The measurement points for the film thickness of the coating film are the same as those in FIG. As shown in Table 2, the film thickness of the coating film from the left end portion to the right end portion of the glass substrate in any of the front end portion (A), the central portion (B), and the rear end portion (C) in the traveling direction of the glass substrate. Is uniform. That is, it is shown that the film thickness is uniform over the entire surface of the glass substrate.
FIG. 8 is a graph showing the data shown in Table 2.

また、本発明は、ロールコータで使用するフォトレジストがカラーフィルタを構成するパターンの形成に用いるフォトレジストであることを特徴としている。
フォトレジストは、例えば、フォトエッチング用のレジストパターンを形成するためにフォトレジストを用いた際には、エッチング後にはそのレジストパターンは剥離除去される。しかし、カラーフィルタにおいては、前記のように、黒色フォトレジストを用いてパターンに形成した樹脂ブラックマトリックスや、着色フォトレジストを用いてパターンに形成した着色画素は、カラーフィルタを構成する部位であり、各々のパターンの性能が集約されカラーフィルタの品質が成り立つものである。

The present invention is also characterized in that the photoresist used in the roll coater is a photoresist used for forming a pattern constituting a color filter.
For example, when a photoresist is used to form a resist pattern for photoetching, the resist pattern is peeled off after etching. However, in the color filter, as described above, the resin black matrix formed in a pattern using a black photoresist and the colored pixels formed in a pattern using a colored photoresist are parts constituting the color filter, The performance of each pattern is integrated and the quality of the color filter is established.

  That is, it is more important that the film thickness of the photoresist formed on the glass substrate is uniform over the entire surface, and the roll coater according to the present invention is applied to the formation of a highly accurate coating film.

It is sectional drawing which shows the outline of an example of a roll coater typically. It is explanatory drawing of the measurement point of the film thickness of a coating film. It is the top view which showed typically an example of the color filter used for a liquid crystal display device. It is sectional drawing in the X-X 'line | wire of the color filter shown in FIG. The data shown in Table 1 are represented in a graph. It is explanatory drawing which showed swelling of the rubber layer after immersing an applicator roll in a black photoresist for 24 hours. It is sectional drawing which shows typically an example of the applicator roll in the roll coater by this invention. The data shown in Table 2 are represented on a graph.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Meta ring roll 2 ... Knife roll 3 ... Applicator roll 10 ... Roll coater 50 ... Glass substrate 51 ... Black matrix 52 ... Colored pixel A ... Glass substrate Tip portion B in the traveling direction of the glass substrate C in the traveling direction of the glass substrate C rear end portion D1 in the traveling direction of the glass substrate diameter D2 in the central portion in the axial direction D Diameter D3 at the right end in the axial direction ... Diameter E1 at the left intermediate portion in the axial direction and the diameter at the right intermediate portion E1 ... Left end E2 at the central portion in the axial direction ... Right inner end F1 at the left end in the axial direction ... Axis Right end F2 at the center in the direction ... Left inner end W at the right end in the axial direction ... Horizontal width W1 of the applicator roll cylinder ... Central portion W2-L in the axial direction of the applicator roll ... Left end W2 in the axial direction -R ... Right axial end W3-L ... Axis left middle W -R ··· axis direction right intermediate section

Claims (4)

In a roll coater for a glass substrate, whose body surface has an applicator roll of EPDM (Ethrene / propylene / diene) ,
1) The constant width diameter (D1) of the central portion (W1) in the axial direction of the applicator roll is smaller than the diameter (D2) of the left end portion (W2-L) in the axial direction and the right end portion (W2-R) in the axial direction. ,
2) The diameter (D3) of the left intermediate portion (W3-L) between the left end (E1) of the axial center portion (W1) and the right inner end (E2) of the axial left end portion (W2-L) is Gradually increasing from the left end (E1) to the right inner end (E2),
3) The diameter (D3) of the right intermediate portion (W3-R) between the right end (F1) of the axial center portion (W1) and the left inner end (F2) of the axial right end portion (W2-R) is A roll coater characterized by gradually increasing from the right end (F1) toward the left inner end (F2). The roll coater according to claim 1, wherein the coating solution used in the roll coater is a photoresist. The roll coater according to claim 2, wherein the photoresist is a photoresist used for forming a pattern constituting a color filter. A method for producing a color filter, wherein the roll coater according to any one of claims 1 to 3 is used to produce a color filter by applying a photoresist on a glass substrate.

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