JPH04256463A - Rigid substrate coating apparatus - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a thick coated portion in the vicinity of the end of the rigid substrate when a coating liquid is applied by a coating device and to improve the yield of the product by providing a coating liquid blow-off means blowing off a thick coated portion being formed at the edge of the coating surface of the rigid substrate in the outer line direction of the rigid substrate. CONSTITUTION:By inserting and conveying the rigid substrate 10 between a microrod bar being dipped the lower part in a coating liquid tank and nip rollers being arranged to face each other above the microrod bar, the coating liquid is applied on the rear of the rigid substrate 10. In this time, the thick coated portion P formed at the edge of the coating surface of the rigid substrate 10 is blown off in the outer edge directions of the rigid substrate 10 by the coating liquid blow-off means 50 consisting of air ejecting nozzles 52a, 52b. Thus, when the coating liquid is applied by the coating deice, the occurrence of a thick coated portion in the vicinity of the end of the rigid base plate is prevented and the yield of the product is improved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard substrate coating apparatus for thinly and uniformly coating a hard substrate with a coating liquid such as photoresist.

0002

2. Description of the Related Art There is a process of coating a hard substrate such as a glass substrate with a coating liquid such as photoresist to a thin and uniform thickness. For example, in the production of color liquid crystal panels, a red color mosaic liquid with a photoresist function is uniformly applied to a glass substrate on which transparent electrodes have been formed in advance, and then exposed to light to harden the color mosaic corresponding to red. A red color mosaic is formed by removing the excess liquid. The same process is then repeated for other colors such as green and blue. When applying a coating liquid to serve as a photoresist in this manner, it is necessary to strictly control and apply the liquid thinly to a uniform thickness. This is because if the thickness of this coating is non-uniform, uneven light transmittance will occur, leading to a decrease in quality.

Conventionally, a spin coater has been used for this coating. This spin coater applies a coating liquid by dropping a coating liquid onto a rotated substrate near the center of rotation and scattering the liquid using centrifugal force. However, in this method using a spin coater, the amount of the liquid that is scattered and thrown away is much larger than the amount of the applied liquid, which is a problem, especially in the case of large substrates. . This has caused a problem of increased costs.

[0004] Therefore, it has been considered to use an apparatus that applies the coating by sandwiching the substrate between a pair of upper and lower rollers disposed horizontally. This device immerses the lower part of the microrod bar, which serves as the lower roller, in the coating liquid, and while feeding the substrate by sandwiching it between the microrod bar and the nip roller located above, the microrod bar coats the bottom surface of the substrate. It is applied.

However, in this case, the coating liquid tends to be applied thickly near the left and right edges of the microrod bar, resulting in thickly coated areas. The reason for this is that near the contact area between the micro rod bar and both edges of the hard substrate, a portion of the coating liquid is pushed outward from both edges of the hard substrate, and this extruded excess coating liquid is transferred to both edges of the hard substrate. This is because it adheres to nearby areas.

Furthermore, when the terminal end of the substrate leaves the microrod bar, the coating solution tends to remain thick on the substrate due to the surface tension and viscosity of the coating solution, resulting in thick coating even near the terminal end of the substrate.

[0007] These thickly coated areas cannot be properly treated by various processing steps such as exposure and cleaning that are set for the regular coating thickness, and some of them remain untreated and this thickness Residues such as debris and debris generated by untreated coated areas get mixed into the coating solution in subsequent steps, causing defective products. For this reason, there was a problem in that the yield of the product decreased.

[0008]

[Problems to be Solved by the Invention] Therefore, the problem to be solved by the present invention is that when applying a coating liquid using a coating device using a roller, it is necessary to apply a coating solution to both sides and the end of the hard substrate in the width direction. The objective is to prevent thick coating from occurring near the edges and improve product yield.

[0009]

According to the present invention, this object is to feed a hard substrate by sandwiching it between a micro rod bar whose lower part is immersed in a coating liquid tank and a nip roller placed oppositely above the micro rod bar. Accordingly, the hard substrate coating apparatus for applying a coating liquid to the lower surface of the hard substrate includes a coating liquid blowing means for blowing away a thickly coated portion formed at the edge of the coating surface of the hard substrate toward the outer edge of the hard substrate. This is achieved by a hard substrate coating apparatus characterized by the following.

The coating liquid blowing means includes a pair of air jet nozzles that jet air outward from both left and right edges in the width direction of the substrate, and a pair of air jet nozzles that jet air outward from the rear edge of the substrate. It can be formed with other air jetting nozzles. It is possible to fix these air jet nozzles and move only the substrate, to fix the substrate and move only the nozzles, or to move both at the same time. The ejection port of the nozzle may be formed long along the side edge or rear edge of the substrate, and the substrate and nozzle may be fixed together.

[0011]

[Operation] When the coating liquid is applied to the lower surface of the hard substrate by the micro rod bar of the coating device, the coating liquid on the left and right edges of the hard substrate becomes thicker, and when the substrate is separated from the micro rod bar, the coating liquid becomes thicker. A thick layer remains on the trailing edge of the board. These thickly coated areas are hit by air ejected from the air ejection nozzle,
Excess coating liquid in thickly coated areas is diffused to both sides of the substrate or to the rear, or is scattered with air. As a result, excess coating liquid from thickly coated areas is removed.

0012

[Embodiment] Fig. 1 is an overall layout diagram of an embodiment of the present invention, Fig. 2
3 is a perspective view of the vicinity of the coating liquid blowing means viewed from below, FIG. 4A is a cross-sectional view of the substrate in the width direction showing the coating liquid being blown off, and FIG. 4B is a view after the coating liquid is blown off. show.

In FIG. 1, reference numeral 10 indicates a glass substrate;
is a roller conveyor, and the glass substrate 10 is conveyed from left to right in the figure with the left and right edges of its lower surface placed on the rollers of the conveyor 12. A coating device 1 is placed in the middle of the conveyor 12.
4 are arranged. This coating device 14 has a microrod bar 16 with a small diameter and a circular cross section, a nip roller 18 with a large diameter facing above the microrod bar 16, and a coating liquid tank 20 into which almost the entire microrod bar 16 except the upper part is contained.

[0014] The micro rod bar 16 is a rod having a circular cross section and a thin metal wire tightly wound around the surface of the rod, and a coating liquid is applied by utilizing the capillary phenomenon caused by the grooves between the metal wires. It is.

As shown in FIG. 2, the coating liquid tank 20 has a long and shallow liquid reservoir 22 in a direction perpendicular to the feeding direction of the substrate 10.
New liquid is supplied to this liquid reservoir 22 from a liquid supply pipe 24, while the coating liquid is discharged from a liquid drain port 26. The liquid supply pipe 24 faces near one end of the liquid reservoir 22, and the liquid drain port 26 opens at the bottom near the other end. The depth of this coating liquid is monitored by a liquid level sensor (not shown) and is always managed to be constant.

The microrod bar 16 is held horizontally so that its upper part is exposed from the liquid. That is, bearing parts 30 and 32 having recesses that open upward in a semicircular arc shape are provided at both ends of the liquid reservoir part 22, and these bearing parts 30 and 32
The micro rod bar 16 is rotatably held between the micro rod bar 16 and caps 34 and 36 that are covered from above. Further, the intermediate portion of the micro rod bar 16 is supported from below by a pedestal member 38. This pedestal member 38 is made of hard synthetic resin with excellent sliding properties, and has a semicircular groove formed along the longitudinal direction on its upper surface that abuts the micro rod bar 16 from below. 16 is prevented from deflecting. Note that the height of this backup member 38 is determined by the number of adjustment screws 4 arranged below.
0 allows fine adjustment from the bottom surface of the coating liquid tank 20.

One end (the end on the back side in FIG. 1) of the micro rod bar 16 projects rearward from the coating liquid tank 20, and this projecting end is connected to an electric motor 44 by a detachable joint 42. This electric motor 44 is connected to the glass substrate 10
The rotation is controlled so that the feed speed of the conveyor 12 is the same as that of the conveyor 12. The surface of the nip roller 18 is made of conductive rubber, and is held with the glass substrate 10 sandwiched between it and the microrod bar 16 so as to apply a predetermined clamping force to the glass substrate 10.

As shown in FIG. 2, the left and right edges of the substrate 10 protrude laterally beyond the coated surface of the microrod bar 16, leaving uncoated portions on both sides. The rollers of the conveyor 12 come into contact with this non-applied portion (see FIG. 3).

50 is a coating liquid blowing means. This means 50 is provided with a pair of air jetting nozzles 52 (52a, 52b) located behind the micro rod bar 16 and jetting air outward from both widthwise edges of the substrate 10 (FIGS. 3, 4A, 4B). Air is sent to these nozzles 52 by an air pump 54.

Next, the operation of this embodiment will be explained. The glass substrate 10 that is sent from the left side to the right side in FIG.
Enter between 8 and 8. Since the coating liquid in the liquid reservoir 22 is attached to the surface of the microrod bar 16 due to its rotation, the coating liquid is applied to the lower surface of the glass substrate 10 as the microrod bar 16 rotates.

Here, since the left and right edges of the substrate 10 protrude outward from the application area of the micro rod bar 16 (
(See FIG. 2), some of the coating liquid pushed out laterally from between the microrod bar 16 and the substrate 10 remains near the left and right side edges of the substrate 10. Therefore, as shown in FIG. 4A, thickly coated portions P, P of the coating liquid are formed on the left and right side edges.

Furthermore, when the substrate 10 is removed from the coating device 14, a portion of the coating liquid that has accumulated between the substrate 10 and the microrod bar 16 adheres to the substrate 10 due to surface tension or viscosity of the liquid. , this is the thickly painted part Q (Fig. 3
).

When the substrate 10 is further fed, the thickly coated portion P of the substrate 10 moves above the pair of left and right air jet nozzles 52. Therefore, as the substrate 10 moves, the nozzle 52
The ejected air blows the coating liquid on the thickly coated portion P outward as shown in FIG. 4A. As a result, some of the excess coating liquid is scattered with the air, and some of it spreads to the lower surface of the substrate 10, and the thickly coated portion P disappears as shown in FIG. 4B.

FIG. 5 is a perspective view showing another embodiment. In this embodiment, another air jet nozzle 60 for removing the thickly coated portion Q on the trailing edge of the substrate 10 is added to the above embodiment.

In this embodiment, the thickly painted portions P on the left and right side edges
After removing the substrate 10, the substrate 10 is rotated by 90 degrees. Then, the thickly coated portion Q at the trailing edge is moved along the upper part of the nozzle 60, and the thickly coated portion Q is blown away.

FIG. 6 is a perspective view showing still another embodiment, and FIG. 7 is a sectional view taken along the line VII-VII. In this embodiment, a long air jet nozzle 52A along thick coating parts P and Q is used.
, 60A are provided. The cross-sectional shape of the nozzle 52A is shown in FIG. The nozzle 60A also has a similar shape. In this case, the substrate 10 first stops above the nozzle 52A, and is sprayed by the nozzle 52A into the thickly coated parts P and P on the side edges (Fig.
, 7). Thereafter, the rear edge of the substrate 10 is moved above the nozzle 60A and stopped, and the thickly coated portion Q (see FIG. 5) is removed.

FIG. 8 is a perspective view showing still another embodiment. In this embodiment, the substrate 10 is stopped and the air jet nozzle 6 is
2, the thick coating portion Q (see FIGS. 3 and 5) on the trailing edge of the substrate 10 is removed. That is, the nozzle 62 is movable on a guide rail 64 held in the width direction of the substrate 10, and is connected to a wire 68 that is driven by a servo motor 66. and nozzle 6
2 moves along the lower surface of the trailing edge of the stopped substrate 10 and scatters the thickly coated portion Q.

Note that the nozzles 52, 52A, 60, 60A,
It is undesirable for the coating liquid blown off by 62 or the like to float nearby. Therefore, as shown in FIG. 4A, it is desirable to provide suction nozzles 70, 70 that suck this floating coating liquid together with the air ejected from the nozzles.

[0029]

Effects of the Invention As described above, the present invention can improve the yield of products because the thickly coated portion of the coating liquid applied by the coating device is blown away by the coating liquid blowing means. 1).

Here, the coating liquid blowing means is a pair of left and right air jet nozzles (Claim 2) for blowing away the thickly coated portion (P) in the width direction of the hard substrate, or the thickly coated portion formed on the trailing edge of the hard substrate. It can be configured with other air jet nozzles (claim 3) for blowing off (Q), and can also be provided with all of these nozzles.

[0031] Also, the nozzle and the substrate have thickly coated parts (P,
Q) may be relatively moved so as to blow it away, or one of them (for example, the substrate) may be stopped and only the other (the nozzle) may be moved (Claim 4). Furthermore, a long nozzle corresponding to the length of the thickly coated portion may be used.

[Brief explanation of the drawing]

FIG. 1: Overall layout of an embodiment of the present invention

[Figure 2] Cross-sectional view of the coating device

[Figure 3] Perspective view of the vicinity of the coating liquid blowing means

[Figure 4A]
A cross-section of the board in the width direction showing the coating liquid being blown away.

[Figure 4B] Diagram also showing after blowing off

[Fig. 5] Perspective view showing another embodiment

[Fig. 6] A perspective view showing another embodiment.

[Fig. 7] Cross-sectional view taken along line VII-VII in Fig. 6

[Fig. 8] A perspective view showing still another embodiment.

[Explanation of symbols]

10 Glass substrate 14 Coating device 16 Micro rod bar 18 Nip roller

Claims (4)

[Claims] 1. A hard substrate is sandwiched between a micro rod bar whose lower part is immersed in a coating liquid tank and a nip roller disposed oppositely above the micro rod bar, and the hard substrate is conveyed to the bottom surface of the hard substrate. A hard substrate coating apparatus for applying a coating liquid, comprising a coating liquid blowing means for blowing away a thickly coated portion formed at the edge of the coating surface of the hard substrate toward the outer edge of the hard substrate. . 2. The hard substrate coating apparatus according to claim 1, wherein the coating liquid blowing means includes a pair of air jet nozzles that jet air outward from both widthwise edges of the hard substrate. 3. The hard substrate coating apparatus according to claim 2, further comprising another air jet nozzle for jetting air backward from the trailing edge of the hard substrate. 4. The hard substrate coating apparatus according to claim 3, wherein the other air jet nozzle is movable along the trailing edge of the stopped hard substrate.